UBIQUITIN-LIGASE INHIBITORS FOR THE TREATMENT OF CANCER

Abstract

The present invention relates to a novel class of compounds and to compositions comprising the same as well as their used as medicaments in the treatment of cancer.

Description

FIELD OF THE INVENTION

The present invention relates to a novel class of compounds and to compositions comprising the same as well as their used as medicaments in the treatment of cancer.

BACKGROUND ART

Carcinoma, the most common type of cancer, arises from epithelial cells. The transition from adenoma to carcinoma is associated with the loss of E-cadherin and, in consequence, the disruption of cell-cell contacts. E-cadherin is a tumor suppressor, and it is down-regulated during epithelial-to-mesenchymal transition (EMT); indeed, its loss is a predictor of poor prognosis. Hakai is an E3 ubiquitin-ligase protein that mediates E-cadherin ubiquitination, endocytosis and finally degradation, leading the alterations of cell-cell contacts. Although E-cadherin is the most established substrate for Hakai activity, other regulated molecular targets for Hakai may be involved in cancer cell plasticity during tumor progression. In other works, the authors of the present invention have employed an iTRAQ approach to explore novel molecular pathways involved in Hakai-driven EMT during tumor progression. Their results show that Hakai may have an important influence on cytoskeleton-related proteins, extracellular exosome-associated proteins, RNA-related proteins and proteins involved in metabolism. Moreover, a profound decreased expression in several proteasome subunits during Hakai-driven EMT was highlighted. Since proteasome inhibitors are becoming increasingly used in cancer treatment, these findings suggest that the E3 ubiquitin-ligase, such as Hakai, may be a better target than proteasome for using novel specific inhibitors in tumor subtypes that follow EMT, such as carcinomas, tumors with mesenchymal phenotype or tumors where enhanced Hakai expression is detected respect to normal tissues. However, until now, compounds capable of effectively inhibiting Hakai-mediated ubiquitination that are especially suitable as therapeutic tools for the treatment of carcinomas have not been disclosed.

The present invention provides for such class of compounds, which includes enantiomers and pharmaceutically acceptable salts thereof, that selectively and effectively inhibit Hakai-mediated ubiquitination, preferably without affecting Hakai protein levels, and that at the same time represent excellent anti-cancer drugs useful in the treatment of a variety of cancers, such as carcinomas

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1. In silico and in vitro screen for E3 ubiquitin-ligase Hakai inhibitors (A) Chemical structure of Hakin-1 and Hakin-5. (B) Predicted binding poses for Hakin-1 (left panel) and Hakin-5 (right panel) molecules docked within Hakai dimers, as determined by the CRDOCK docking program. (C) In vivo Hakai-dependent ubiquitination assay in 293T cells transfected with Flag-Hakai, v-Src and HA-ubiquitin in presence of either DMSO or compound Hakin-1. (D) In vivo Hakai-dependent ubiquitination assay in 293T cells transfected with Flag-Hakai, v-Src and HA-ubiquitin in the presence of DMSO or compound Hakin-5. (E) In vivo ubiquitination assay in 293T cells transfected with v-Src and HA-ubiquitin in the presence of DMSO or compound Hakin-1. (F) Effect of Hakin-1 on the Hakai-dependent ubiquitination of the E-cadherin complex. pcDNA-Flag-Hakai, pcDNA-myc-E-cadherin, pSG-v-Src and pBSSR-HA-ubiquitin were transiently transfected into 293T cells. Immunoprecipitation was performed with the anti-E-cadherin antibody before western blotting using the indicated antibodies.

FIG. 2. Hakin-1 induces cytotoxicity and an epithelial phenotype on epithelial tumour cell lines. (A) HT29 and LoVo cells were treated an increasing range of concentrations of Hakin-1 or Hakin-5 and cell viability was measured by MTT assay. Assay was performed in 6 replicates and represented as mean±SD of three independent experiments. (B) Cell viability was measured as indicated in (A) for MDCK, Hakai-MDCK cell lines (clone 4 and clone 11) using Hakin-1 (upper panel) or Hakin-5 (bottom panel). (C-D) Phase-contrast images of HT29 and LoVo cell lines (C) and MDCK, Hakai-MDCK cell lines, clone 4 and clone 11 (D) under Hakin-1 or Hakin-5 treatment. Images were obtained using a 20× objective.

FIG. 3. Hakin-1 induces mesenchymal-to-epithelial transition in epithelial tumour cell lines. (A) Western blotting analyses of EMT markers upon Hakin-1 treatment in HT-29 cell line (left panel), and quantification by densitometry is shown (right panel). (B) Western blotting analyses of EMT markers upon Hakin-1 treatment in LoVo cells (left panel), and quantification by densitometry is shown (right panel). GAPDH was used as loading control. Quantifications were performed as indicated in Materials and Methods and the western blotting data are representative of three experiments. Data shows the average of three independent experiments and are represented as mean±SD (*p<0.05; **p<0.01; ***p<0.001). (C) Immunofluorescence of E cadherin in HT-29 and LoVo cell lines in presence of DMSO or Hakin-1 treatment after 48 h. Images were obtained with a 40× objective. Quantification was performed with Image J programme and results are expressed as mean±SD of three independent different experiments (**p<0.01; *** p<0.001). Scale bar, 250 μM for HT29 cells and 175 μμM for LoVo cells.

FIG. 4. Antiproliferative and antioncogenic effect of Hakin-1 in tumour epithelial cells. (A) HT29 and LoVo cells were treated with Hakin-1 for 48 h and proliferation was measured by a BrdU assay as indicated in Material and Methods. Results are expressed as mean±SD of eight replicates and experiments were repeated three times (*p<0.05; ** p<0.01; *** p<0.001). (B) HT29 and LoVo cells were treated with Hakin-5 for 48 h and proliferation was measured as indicated in A (C) MDCK and Hakai-MDCK cells were treated with increasing concentrations of Hakin-1 for 48 h and proliferation was measured as indicated in A. (D) Soft agar assay in HT29 (left panel) and Hakai-MDCK (right panel) cell lines. Colonies grew for 28 days (HT29) or 21 days (Hakai-MDCK) and were counted as indicated in Materials and Methods. Quantification of the colonies was performed in triplicates and represented as mean±SD of three independent experiments (**p<0.01; *** p<0.001).

FIG. 5. Hakin-1 reduces cell invasion and cell migration of epithelial tumour cells. (A) Invasion assay in LoVo cell line was performed as described in Materials and Methods. Cells were treated in presence of DMSO or Hakin-1 for 48 h before being seeded into an invasion chamber. Representative images were taken using the 20× objective (upper panel) and quantification of the photographed invasive cells are shown (bottom panel). (B) Invasion assay was performed as indicated in A by using MDCK and Hakai-MDCK cells. (C) Migration assay in HT29 cells was analysed after treatment with DMS or Hakin-1 during 48 h. Cells were seeded in a migration chamber as described in Materials and Methods. Representative images are shown (upper panel) and quantification of migrating cells is shown (bottom panel). Results are represented as mean±SD of triplicates of three independent experiments (***p<0.001).

FIG. 6. Hakin-1 inhibits tumour growth in xenografted mice. (A) Effects of Hakin-1 on tumour growth in nude mice inoculated into the flank with Hakai-MDCK cells (n=6 tumours). Tumour growth curve is shown in upper panel. Error bars represented the mean±SEM (*p<0.05). A schematic representation of the experiment design is shown in the bottom panel. (B) H&E staining of Hakai-MDCK tumours at the end point treated with DMSO (left panel) or Hakin-1 (right panel). Images were obtained with a 20× objective. Scale bar, 300 μM. (C) H&E staining showing the infiltration of a blood vessel by tumour cells. Images were obtained with a 20× objective. Scale bar, 500 μM. (D) Immunohistochemistry of Ki67 marker in Hakai-MDCK tumours treated with DMSO (left panel) or Hakin-1 (right panel). Representative images were obtained with 40× objective. Scale bar, 500 μM. Quantification of the percentage of positive cells is shown in the bottom panel. (E) Representative image of Hakai-MDCK tumour in nude mice stained with H&E is shown. Pictures were obtained with a 40× objective (upper panel). Quantification of the number of mitosis in high magnification field is shown (bottom panel). Scale bar, 500 μM. (F) Immunohistochemistry of CD31 marker in Hakai-MDCK tumour of injected nude mice treated with DMSO (left panel) or Hakin-1 (right panel). Images were obtained with a 20× objective. Scale bar, 500 μM. Quantification of the number of fields is shown in the bottom panel and is expressed as mean±SEM (***p<0.001).

FIG. 7. Hakin-1 treatment reduces mesenchymal markers of tumours xenograft and micrometastasis formation in lung of nude mice. (A-C) Immunohistochemical staining for Hakai (A), E-cadherin (B) and N-cadherin (C). Representative images were obtained with a 20× objective (upper panel). Quantification of significantly protein expression intensity is shown in bottom panel. (D) Immunohistochemical staining for Cortactin antibody and protein expression quantification is shown (upper and lower panels, respectively). Images were obtained with 40× objective. (E) H&E staining of mice lungs. Representative images were obtained with a 10× objective. (F) Real-time quantitative PCR using primers for HA epitope and Hakai to detect the presence of DNA of Hakai-MDCK cells into the mice lung. Results are expressed as mean±SEM (***p<0.001). Scale bar, 500 μM.

FIG. 8. Hakin-5 does not affect the EMT markers expression. (A) Western blotting of E-Cadherin, Cortactin and Hakai in HT29 cells after Hakin-5 treatment for 48 h with. (B) Immunofluorescence of E-Cadherin in HT29 cells treated with Hakin-5 for 48 h. Images were taken with the 40× objective. Scale bar, 250 μM.

FIG. 9. Effect of Hakin-1 in human cancer cells. Breast cancer MCF7 cell, prostate cancer PC-3 cells, bladder cancer 5637 cells liver, renal cancer ACHN and cancer liver cancer HepG2 cells were treated with Hakin-1 for 48 h and proliferation was measured by a BrdU assay as indicated in Material and Methods. Results are expressed as mean±SD of eight replicates and experiments were repeated three times (*p<0.05; **p<0.01; ***p<0.001).

FIG. 10. Hakin-1 does not affect cell apoptosis in vivo in xenograft mouse models. Tunel assay was performed as indicated in Materials and Methods. A representative image is shown (left panel) and quantification of the number of positive cells is also represented (right panel) as mean±SEM. Images were taken with 20× objective. Scale bar, 125 μM.

FIG. 11. Intact cell morphology and tissue structure of liver and kidney in vivo in xenograft mouse models treated with Hakin-1. H&E staining of liver (upper panel) and kidney (bottom panel) of nude mice treated with 5 mg/kg of DMSO or Hakin-1. Images were taken with a 10× objective. Scale bar, 500 μM.

FIG. 12. Effect of selected analogues on the cytotoxicity in HT29 epithelial tumour cell lines. Cells were treated with increasing range of concentrations (50 μM, 100 μM, 250 μM and 500 μM) of (A) Ketophenyls A-1, A-7, A-8 and A-9 (B) ketoheteroaryls: A-23 and A-25 (C) Cyclic amides: A-10 and A-16 and (D) Bencylamide A-6.1. Cell viability was measured by MTT assay. Assays were performed using six replicates and represented as mean±SD of two independent experiments.

FIG. 13. Effect of analogues inhibitors on Hakai-dependent ubiquitination. In vivo Hakai-dependent ubiquitination assay in 293T cells transfected with Flag-Hakai, v-Src and HA-ubiquitin in the presence of DMSO or selected analogues. (A) Ketophenyls A-7 and A-9 (B) Ketophenyls A-9 and Cyclic amides: A-10 and A-16 and (C) ketoheteroaryls: A-23.

FIG. 14. Compound 1 (Hakin-1), chemical structure, phys-chem. parameters and binding mode (docking).

FIG. 15. Summed XIC of all the metabolites found in 0 minute mouse samples.

FIG. 16. Summed XIC of all the metabolites found in 10 minute mouse samples.

FIG. 17. Summed XIC of all the metabolites found in 20 minute mouse samples.

FIG. 18. Metabolite profiling analytical data for parent compound, Hakin-1.

FIG. 19. Metabolite profiling analytical data for metabolite MKH1, Reduction.

FIG. 20. Synthesis route for MKH1. Synthesis was carried out following the scheme given.

FIG. 21. Summary of the structures of K1, K2, K8 and K33.

FIG. 22. Immunofluorescence images and quantification of E-cadherin expression at cell-cell contacts in human colon cancer cells treated with K1 and K2 compounds. The colorectal adenocarcinoma cell line HT-29 was exposed to 100 μM or 20 μM of the indicated compounds or DMSO vehicle control, for 48 hours (A) Representative image of E-cadherin expression at cell-cell junctions was taken. Scale bar: 100 μm. (B) Quantification of E-cadherin expression at cell-cell contacts. Each mean is an average of 12, 6 or 3 wells, ns, not significant; *P<0.05; **P<0.01; ***P<0.001; P<0.0001 for difference from control by ANOVA followed by Dunnett's procedure or unpaired t-test.

FIG. 23. Immunofluorescence images and quantification of E-cadherin expression at cell-cell contacts in human colon cancer cells treated with Nocodazol. (A) Immunofluorescence images of E-cadherin of HT-29 cell line treated with Nocodazole and DMSO vehicle controls at the indicated concentrations and times. Scale bar: 100 μm. (B) Quantification of E-cadherin expression at cell-cell contacts in HT-29 cell line treated with Nocodazole and DMSO vehicle controls at the indicated concentrations and times. Each mean is an average of 12, 6 or 3 wells, ns, not significant; *P<0.05; **P<0.01; ***P<0.001; P<0.0001 for difference from control by ANOVA followed by Dunnett's procedure or unpaired t-test.

FIG. 24. Cell cycle analysis of human colon cancer cells exposed to indicated compounds or DMSO. CyteSeer software can measure relative DNA content by quantifying Total Integrated Intensity (TII) of the Nuclear Image (Ni) on the Nuclear Mask (Nm). HT-29 cells treated with K1, K2 compounds, or 0.1% DMSO vehicle control, for 48 hours. NOTE: The ploidy histogram for 48 hour or DMSO vehicle control contains cell numbers from 12 wells respectively.

FIG. 25. Cell cycle analysis of human colon cancer cells exposed to Nocodazol or DMSO. CyteSeer software can measure relative DNA content by quantifying Total Integrated Intensity (TII) of the Nuclear Image (Ni) on the Nuclear Mask (Nm). HT-29 cells treated with Nocodazol at indicated times and concentration, or DMSO as vehicle control, for 24 hours. NOTE: The ploidy histogram for 48 hour or 24 hours DMSO vehicle control contains cell numbers from 12 or 6 wells respectively, and therefore has a different y-axis compared to the ploidy histograms for the test compounds, which only contains data from 3 replicate wells.

FIG. 26. Immunofluorescence images of E-cadherin expression at cell-cell contacts in human colon cancer cells treated with MKH1. The colorectal adenocarcinoma cell line HT-29 was exposed to 5 μM, 20 μM and 100 μM of MKH1 or DMSO vehicle control, for 48 hours and representative image of E-cadherin expression at cell-cell junctions was taken (upper image). Quantification (lower image) was performed with Image J programme and results are expressed as mean±SD of three independent different experiments (**p<0.01; *** p<0.001).

FIG. 27. Immunofluorescence images of E-cadherin expression at cell-cell contacts in human colon cancer cells treated with K8. The colorectal adenocarcinoma cell line HT-29 was exposed to 5 μM, 20 μM, 50 μM and 100 μM of K8 or DMSO vehicle control, for 48 hours and representative image of E-cadherin expression at cell-cell junctions was taken (upper image). Quantification (lower image) was performed with Image J programme and results are expressed as mean±SD of three independent different experiments (**p<0.01; *** p<0.001) and K1 was used as positive control.

FIG. 28. Immunofluorescence images of E-cadherin expression at cell-cell contacts in human colon cancer cells treated with K33. The colorectal adenocarcinoma cell line HT-29 was exposed to 20 μM, and 100 μM of K8 or DMSO vehicle control, for 48 hours and representative image of E-cadherin expression at cell-cell junctions was taken (upper image). Quantification (lower image) was performed with Image J programme and results are expressed as mean±SEM of three independent different experiments (**p<0.01; *** p<0.001) and K1 was used as positive control.

FIG. 29. Effect of MKH1 and K8 on cell proliferation in human colon cancer cells. Colon cancer HCT116 cells were treated with indicated compounds for 48 h and proliferation was measured by a BrdU assay as indicated in Material and Methods. Results are expressed as mean±SD of eight replicates and experiments were repeated three times (*p<0.05; **p<0.01; ***p<0.0001).

FIG. 30. Hakin-1, K1, MKH1 and K8 inhibitors reduce cell invasion of human epithelial tumour cells. Invasion assay was performed in HT29 cell line as described in Materials and Methods. Dose/response experiments were performed by treating cells for 48 h in the presence of the inhibitors Hakin-1, MKH1, K1, and K8 or DMSO as control, before being seeded into an invasion chamber. Quantification of the photographed invasive cells are shown. Results are represented as mean±SD of triplicates of three independent experiments (*p<0.05; **p<0.01; ***p<0.001).

FIG. 31. Analysis of cytotoxicity of K1, MKH1 and K8 at the tested concentrations. (A) HCT116 colon cancer cells and non-cancerous HEK293T cells were treated with increasing range of concentrations of K1 (A), MKH1 (B) and K8 (C) and cell viability was measured by MTT assay as described in material and methods. Assay was performed in 6 replicates and represented as mean±SD of three independent experiments.

FIG. 32. Effect of K1, MKH1 and K8 inhibitors on Hakai-induced ubiquitination. In vivo Hakai-dependent ubiquitination assay in 293T cells transfected with Flag-Hakai and HA-ubiquitin in presence of either DMSO or compounds K1, MKH1 and K8.

DESCRIPTION OF THE INVENTION

The present invention is based on our previous identification of 4-Tetrazolylbenzoic acids Hakin-1, Hakin-2 and Hakin-6 (from hereinafter compounds #1, 2 and 6)

as inhibitors of Hakai capable of competing for the HYB binding site that is only present in the Hakai dimer. As already discussed in previous patent application from the inventors PCT/EP2019/081522, Hakai has been reported to be involved in tumor progression; therefore inhibitors of the interaction between Hakai and E-cadherin might be useful for the treatment of cancer. In this sense and as shown in the examples of PCT/EP2019/081522 (which are fully reproduced herein), inhibition of tumor progression was demonstrated in vitro and in vivo utilizing compound #1.

Therefore, in PCT/EP2019/081522 they solved the technical problem of providing compounds having excellent anti-oncogenic effects and low toxicity. These compounds could advantageously be used as a medicament and, particularly, in the treatment of a variety of cancers, such as carcinomas, in particular the gastrointestinal track cancer including month (oral cancer), esophagus, stomach, and small and large intestines (such as rectal or colon cancer). It also included skin cancer, mammary gland (breast cancer), pancreas cancer, lung cancer, head and neck cancer, liver cancer, ovary cancer, cervix cancer, uterus cancer, gallbladder cancer, penile cancer, and urinary bladder cancer (such as renal, prostate or bladder cancer). Indeed, collectively, said data, as illustrated in the examples of PCT/EP2019/081522, showed that Hakin-1 was a specific inhibitor for Hakai-mediated ubiquitination, without affecting Hakai protein levels (Example 1). In addition, Hakin-1 was able to suppress proliferation in Hakai-MDCK cell while no effect was detected in MDCK cells (FIG. 4c). Hakin-1 also inhibited cell proliferation in other epithelial cells lines such as breast cancer MCF7 cell, prostate cancer PC-3 cells, bladder cancer 5637 cells, liver cancer HepG2 cells and renal cancer ACHN cells. All these findings supported an antitumor effect of Hakin-1 by acting on cell proliferation, oncogenic potential, cell motility and invasion. In addition, PCT/EP2019/081522 further showed that Hakin-1 treatment inhibited tumor growth in nude mice apparently without systemic toxicity (FIG. 11). Furthermore, Hakin-1 caused a significant reduction of micrometastasis detected in lung of the Hakai-MDCK xenograft mice compared to the control DMSO treated mice, while no detection was found in lung of non-transformed MDCK-injected mice (FIG. 7f). This result underscore that Hakin-1 inhibited the metastasis to lung in vivo.

Compound #1 (as already stated, also referred to as Hakin-1) was a 1,5-disubstituted tetrazole, a chemically and metabolically stable pharmacophore fragment frequently used in drug development (Tetrazole Derivatives as Promising Anticancer Agents, E. A. Popova et al., Anticancer Agents Med Chem. 2017 Mar. 27. doi: 10.2174/1871520617666170327143148, Epub ahead of print). The tetrazole ring was substituted with a 4-carboxyphenyl group in position 1. In position 5, it was connected via a mercaptomethylcarbonyl linker with another phenyl ring.

Important physico-chemical parameters like molecular weight, calculated lipophilicity log P and polar surface area were in the desired range for orally absorbed drugs that are unlikely to pass the blood-brain barrier. According to a snapshot from a docking study with compound 1 in the Hakai HYB site, the carboxyphenyl moiety makes 3 important hydrogen bond interactions with the protein and is likely to mimick the binding mode of the phosphotyrosine subtrates. Further hydrogen bonds are formed by two of the tetrazole nitrogen atoms which provide additional stability and hold the tetrazole-carboxyphenyl unit on both ends in a defined binding mode. Based on the above, in PCT/EP2019/081522 the following subunit were described as essential and were considered as the core structure for identifying derivatives of compound #1:

Common Structural Feature of Compounds #1, 2 and 6.

Departing from such common structural core, a number of modifications in order to optimize the activity (and other properties) of these compounds and provide analogs of these compounds, could be made. In this sense, in PCT/EP2019/081522 it was therein indicated that there were several opportunities of introducing modifications in different parts of the molecule that represent an important objective in the optimization process and in the provision of analogs of compounds #1, 2 and 6. In this regard, a medicinal chemistry program would start focusing on the chemical space around compound #1 and with less priority around compounds #2 and #6. With this in mind, they provided a group of different analogs of compounds #1, #2 and #6, useful in the invention described in PCT/EP2019/081522. Notably, useful as medicaments and, particularly, in the treatment of a variety of cancers, such as carcinomas, in particular tumors arising from the epithelial layers of the gastrointestinal track including month (oral cancer), esophagus, stomach, and small and large intestines (such as rectal or colon cancer). It also included skin cancer, mammary gland (breast cancer), pancreas cancer, lung cancer, head and neck cancer, liver cancer, ovary cancer, cervix cancer, uterus cancer, gallbladder cancer, penile cancer, and urinary bladder cancer (such as renal, prostate or bladder cancer).

A first class of analogs which was provided by connecting the core structure to a ring structure (Cy=any cycle) in order to find those analogs that were similar to compounds #1 and #2 was described as:

These types of compounds were grouped as shown below in PCT/EP2019/081522, according to the following structural subclasses a) to c).

a) Ketophenyls (Including Compound #1):

It is noted that these structures could comprise a substituent on the phenyl ring or in another part of the molecule, e.g. on the carboxyphenyl ring or on the carbon atom between the sulfur and the carbonyl group. The latter case was exemplified as follows:

Moreover, the following examples, illustrated the introduction of modifications such as a cyclopropyl bridge or the addition of substituents on the carboxyphenyl ring:

Particular examples of Ketophenyl compounds useful to practice the present invention were illustrated as follows:

4-(5-((2-(4-nitrophenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-acetylphenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-(methylsulfonyl)phenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(2-((1-(4-carboxyphenyl)-1H-tetrazol-5-yl)thio)acetyl)benzoic acid

4-(5-((2-(4-carbamoylphenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-oxo-2-(4-sulfamoylphenyl)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-(methylsulfonamido)phenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-(cyclopropanecarboxamido)phenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-bromophenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-cyanophenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-oxo-2-(4-(trifluoromethyl)phenyl)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-cyclopropylphenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-(cyclopropylamino)phenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-morpholinophenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-(4-methylpiperazin-1-yl)phenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-methoxyphenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-(5-fluoropyridin-3-yl)phenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

b) Ketoheteroaryls:

Further substructures provided by PCT/EP2019/081522 connecting the core structure to a ring structure (Cy=any cycle), were listed as Ketoheteroaryls. In this sense, it was therein indicated that a typical exploration in medicinal chemistry would be to replace the phenyl group present in compound #1 by a heteroaryl group which represents a similar aromatic ring with additional heteroatoms. PCT/EP2019/081522 provided 6 examples of analogs that fell into this category:

6-membered heteroaryls (like pyridines, pyrimidines, pyridazines) that were structurally closer to phenyl as illustrated below, also formed part of PCT/EP2019/081522:

Moreover, particular examples of ketoheteroaryls compounds useful to practice the invention identified in PCT/EP2019/081522, were the following:

4-(5-((2-oxo-2-(pyridin-4-yl)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(6-aminopyridin-3-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(6-hydroxypyridin-3-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(6-morpholinopyridin-3-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(5-cyanopyridin-2-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-oxo-2-(pyrimidin-4-yl)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-oxo-2-(pyridazin-4-yl)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-oxo-2-(pyrazin-2-yl)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

c) Cyclic Amides (Including Compound #2):

Still further substructures provided by PCT/EP2019/081522 connecting the core structure to a ring structure (Cy=any cycle), were listed as Cyclic amides, as depicted below:

In particular, substituted indoline (and indole) analogs as illustrated below:

More particularly, any of the compounds substituted on the phenyl ring shown herein below:

4-(5-((2-(5-bromoindolin-1-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(5-cyanoindolin-1-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(5-cyclopropylindolin-1-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(5-morpholinoindolin-1-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-oxo-2-(5-(pyridin-3-yl)indolin-1-yl)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(5-fluoroindolin-1-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

1-(2-((1-(4-carboxyphenyl)-1H-tetrazol-5-yl)thio)acetyl)indoline-5-carboxylic acid

4-(5-((2-(5-carbamoylindolin-1-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

With modifications in other parts of the molecule:

4-(5-((1-(5-cyanoindoline-1-carbonyl)cyclopropyl)thio)-1H-tetrazol-1-yl)benzoic acid

2-fluoro-4-(5-((1-(5-morpholinoindoline-1-carbonyl)cyclopropyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((1-(5-carbamoylindoline-1-carbonyl)cyclopropyl)thio)-1H-tetrazol-1-yl)benzoic acid

3-cyclopropyl-4-(5-((2-(5-fluoroindolin-1-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

3-cyano-4-(5-((2-(5-cyclopropylindolin-1-yl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid.

In addition, PCT/EP2019/081522 further taught that the different substructures a) to c) above provided by connecting the core structure to a ring structure (Cy=any cycle) could be further substituted as follows:

1. Examples of structures having a substitution on the mercaptoacetyl linker

4-(5-((2-methyl-1-(4-nitrophenyl)-1-oxopropan-2-yl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((1-(4-carbamoylphenyl)-2-methyl-1-oxopropan-2-yl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-methyl-1-(4-(methylsulfonamido)phenyl)-1-oxopropan-2-yl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((1-(4-cyanophenyl)-2-methyl-1-oxopropan-2-yl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((1-(4-nitrobenzoyl)cyclopropyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((1-(4-carbamoylbenzoyl)cyclopropyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((1-(4-(methylsulfonamido)benzoyl)cyclopropyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((1-(4-cyanobenzoyl)cyclopropyl)thio)-1H-tetrazol-1-yl)benzoic acid 2. Examples of structures having a substitution on the carboxyphenyl moiety

2-cyano-4-(5-((2-(4-nitrophenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(4-carbamoylphenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)-2-fluorobenzoic acid

2-cyclopropyl-4-(5-((2-(4-(methylsulfonamido)phenyl)-2-oxoethyl)thio)-1H-tetrazol yl)benzoic acid

4-(5-((2-(4-cyanophenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)-3-fluorobenzoic acid

3-cyano-4-(5-((2-(4-nitrophenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

3-cyclopropyl-4-(5-((2-(4-(methylsulfonamido)phenyl)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

On the other hand, an entirely new group or class of compounds that derived from extending the core structure with a nitrogen atom, a carbon atom and a cyclic group to provide compounds resembling compound #6, was provided in PCT/EP2019/081522 under the subclass benzylamides:

Compounds falling within this category are herein indicated below:

Other compounds pertaining to this class of compounds are:

4-(5-((2-((3-cyanobenzyl)amino)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-((3-cyclopropylbenzy)amino)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-((3-morpholinobenzy)amino)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-oxo-2-((3-(pyridin-3-yl)benzyl)amino)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-((3-carbamoylbenzyl)amino)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-((3-fluorobenzyl)amino)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

With modifications in other parts of the molecule:

4-(5-((1-((3-cyanobenzyl)carbamoyl)cyclopropyl)thio)-1H-tetrazol-1-yl)benzoic acid

3-cyano-4-(5-((2-((3-cyclopropylbenzyl)amino)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((1-((3-morpholinobenzyl)carbamoyl)cyclopropyl)thio)-1H-tetrazol-1-yl)benzoic acid

2-fluoro-4-(5-((2-oxo-2-((3-(pyridin-3-yl)benzyl)amino)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-((3-carbamoylbenzyl)amino)-2-oxoethyl)thio)-1H-tetrazol-1-yl)-3-cyclopropylbenzoic acid

4-(5-((1-((3-fluorobenzyl)amino)-2-methyl-1-oxopropan-2-yl)thio)-1H-tetrazol-1-yl)benzoic acid

With heteroaryls:

4-(5-((2-oxo-2-((pyridin-4-ylmethyl)amino)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-oxo-2-((pyrimidin-4-ylmethyl)amino)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-oxo-2-((pyridazin-4-ylmethyl)amino)ethyl)thio)-1H-tetrazol-1-yl)benzoic acid

4-(5-((2-(((5-cyanopyridin-2-yl)methyl)amino)-2-oxoethyl)thio)-1H-tetrazol-1-yl)benzoic acid

It is herein noted that all compounds indicated in PCT/EP2019/081522 were encompass by the following general formula:

wherein:

• • A represented a group selected from aryl, heteroaryl and cyclic amides optionally substituted by 1 or 2 groups that were independently selected from:
  •  a) halogen atom, NO₂, —CN, —N(R^a)R^b, —OR^a, —C(═O)R^a, —C(═O)OR^a, —C(═O)N(R^a)R^b, —OC(═O)—R^a, —N(R^c)C(═O)R^b, —NR^cSO₂R^a, —SO₂N(R^a)R^b, —SR^a, —S(O)R^a, —S(O)₂R^a;
  •  b) linear or branched C₁-C₆ alkyl, optionally substituted by 1, 2 or 3 halogen atoms;
  •  c) C₃-C₆ cycloalkyl which optionally contains 1 or 2 heteroatoms selected from 0, S and N, and which ring is optionally substituted by C₁-C₃ alkyl;
  •  d) phenyl or C₅-C₆ heteroaryl each optionally substituted by halogen atom, cyano group, C₁-C₃ alkyl or cyclopropyl;
  • each R^a, R^b and R_c independently represented:
  •  a) hydrogen atom,
  •  b) linear or branched C₁-C₁₂ alkyl, C₃-C₆ cycloalkyl and C₄-C₆ heterocycloalkyl, which were optionally substituted by 1, 2 or 3 substituents selected from a carbonyl group, halogen atom, hydroxy, phenyl, C₃-C₆ cycloalkyl, linear or branched C₁-C₆ alkoxy, amino, alkylamino, dialkylamino, linear or branched C₁-C₆ alkylcarbonyl,
  •  c) phenyl or C₅-C₆ heteroaryl group, which were optionally substituted by 1, 2 or 3 substituents selected from halogen atom, cyano group, linear or branched C₁-C₆ alkyl, linear or branched C₁-C₆ haloalkyl, hydroxy, linear or branched C1-C6 alkoxy, amino, alkylamino, dialkylamino;
  •  d) R^a and R^b form together with the nitrogen atom to which they were attached, a 3- to 8 membered ring which optionally contained a further heteroatom selected from O, N and S, and which ring was optionally substituted by 1, 2 or 3 substituents selected from carbonyl group, linear or branched C₁-C₆ alkyl, linear or branched C₁-C₆ haloalkyl, linear or branched C₁-C₆ alkylcarbonyl;
  • x and y were integers independently selected from 0 and 1;
  • R¹ represented a group selected from hydrogen, cyclopropyl or linear or branched C₁-C₆ alkyl, wherein said alkyl was optionally substituted by 1, 2 or 3 halogen atoms;
  • when y was 0, then 2 or 3 carbon atoms of R¹ can form a 5- or 6-membered ring together with the neighboring nitrogen atom and the 2 adjacent carbon atoms of the aromatic ring to which the nitrogen is attached;
  • each R² and R³ independently represented a group selected from hydrogen, cyclopropyl or linear or branched C₁-C₆ alkyl; optionally R² and R³ can form a 3- or 4-membered spiro ring together with the carbon atom to which they are both attached;
  • z was an integer selected from 0, 1, 2 or 3;
  • R⁴ represented a group selected from —CN, cyclopropyl or linear or branched C₁-C₆ alkyl, said alkyl was optionally substituted by 1, 2 or 3 halogen atoms; wherein the group R⁴, if present, replaces the hydrogen atom of one of the groups CH present in the phenyl ring to which R⁴ is attached;

as well as any pharmaceutically acceptable salts thereof.

However, the same inventors of PCT/EP2019/081522 have now realized that further analogs of compounds #1, #2 and #6, useful in the invention described in PCT/EP2019/081522, fail to be encompass by the above general chemical formula. Notably, these new compounds shall also be useful as medicaments and, particularly, in the treatment of a variety of cancers, such as carcinomas, in particular tumors arising from the epithelial layers of the gastrointestinal track including month (oral cancer), esophagus, stomach, and small and large intestines (such as rectal or colon cancer). Such medical use shall also include skin cancer, mammary gland (breast cancer), pancreas cancer, lung cancer, head and neck cancer, liver cancer, ovary cancer, cervix cancer, uterus cancer, gallbladder cancer, penile cancer, and urinary bladder cancer (such as renal, prostate or bladder cancer).

In this sense, as already indicated above, those compounds described as useful in PCT/EP2019/081522, made the interactions with the protein as indicated in FIG. 14, wherein the main interactions originated from the right-hand side of the molecule since the acid interacts with a tyrosine and histidine residue and the tetrazole interacts with a backbone NH in the protein sequence. Yet, importantly, group A of the general structure of formula (I) and the linkage structure occupy a large pocket to the left of the molecule and the carbonyl function appears to make no interaction with the protein, therefore suggesting that it is not essential for activity. Additionally, although the nitro group in compound 1 might interact with the protein, screening suggests that even if this is the case this interaction might not be strictly essential. For these reasons, having an amide/ketone can in some circumstances be an advantage even if no interaction with the protein is made since it provides conformational rigidity, and lowers the lipophilicity of the formula (I) compounds.

For these reasons, in the present invention we herein provide the following further analogs of compounds #1, #2 and #6, useful in the invention described in PCT/EP2019/081522, but which fail to be encompassed by the above general chemical formula (I):

Compound (1) above is also referred to herein as compound K1.

Based on the data available it is clearly plausible that these group of compounds (from hereinafter refer to as “Group 1A”) would be active, as they maintain the key pharmacophoric groups in the right-hand phenyl tetrazole/carboxylic acid and have a size that fits into the pocket. In addition, since the pocket has a hydrophobic nature, the lipophilic larger groups of each of the above compounds will easily interact with the protein. On the other hand, the smaller groups have polar hydrophilic groups present in most cases (6, 7)—which could be accommodated without interacting with the protein surface—these polar groups may offer advantage in terms of solubility and lower lipophilicity to reduce metabolism/interaction with key metabolic enzyme such as cytochrome P450s.

In addition, we herein provide the following further analogs (from hereinafter refer to as “Group 3A”) of compounds #1, #2 and #6, useful in the invention described in PCT/EP2019/081522, but which fail to be encompassed by the above general chemical formula (I):

As can be notice, in the original Markush formula (I), (A) could be selected from an aryl, heteroaryl or cycloalkyl, these groups occupy a large pocket which has the potential to accommodate a wider variety of other groups. It is therefore perfectly plausible that non-cyclic amides such as those of compounds 14, 15, 16, 17, 19, 20, 21, 22, or 23 above, can be accommodated as these fit into the pocket and are capable of making a hydrophobic interaction with the protein. On the other hand, substitution on the group (Y) would also be predicted to be tolerated from the protein structure (compound 24).

Furthermore, we herein provide the following further analogs (from hereinafter refer to as “Group 2A”) of compounds #1, #2 and #6, useful in the invention described in PCT/EP2019/081522, but which fail to be encompassed by the above general chemical formula (I):

Compound (27) is also referred to herein as K2.

These compounds lie outside the existing Markush formula (I) as they contain an acid group in the meta position of the benzene ring, and only para derivatives are covered in the original application. The proposed binding mode (see FIG. 14) indicates that the acid interacts with a histidine in the protein. In this sense, it is perfectly plausible that if there is movement in the protein or flexibility in the binding mode or in the protein then a small adjustment will allow the meta acid to interact in the same way as the para acid without effecting the other key interactions as these groups are very close together.

In this sense, please compare the acids (a—para) and (b—meta) which show the close proximity.

In addition, even If there is no flexibility then the meta acid can still make a partial interaction—see figs (d) and (e) which demonstrate that one of the oxygens can always occupy the same region of space when comparing the para and meta isomers. It is also worth noting that an acid can make both H-bond donor and acceptor interactions as the bonds can flip between forms (tautomerism) either mode of interaction is possible in each case (please compare (b) and (c), and (d) and (e)). Moreover, In 2 cases (compounds 29 and 31 above) a chlorine atom is present in the para position next to the acid in the meta position. In these 2 cases it is possible that the complete H-bonding network of the acid can be maintained as chlorine has also been demonstrated to behave like a H-bond donor and interact with carbonyl groups (J Med Chem. 2010, 53(14): 5061-5084).

Furthermore, we herein provide the following further analog/metabolite (from hereinafter refer to as the derivative of compound #1) useful in the invention described in PCT/EP2019/081522:

Isomers of the above compounds are also encompass by the present invention as illustrated below:

Compounds (34) and (35) above are also referred to herein as MKH1. The chemical synthesis of MKH1 is illustrate herein in FIG. 20.

The derivative of compound #1 is a novel metabolite of compound #1. The metabolite was identified after incubating compound #1 with mouse hepatocytes. Mass spectrometry indicated that the metabolite had molecular weight two mass units higher than the parent, suggesting a reduction had taken place. Using a combination of High-performance Liquid Chromatography and mass spectrometry (LCMS), this metabolite was shown to be more polar than the parent indicating that reduction of the ketone had occurred which was subsequently confirmed by investigating the fragments present in the mass spectrometry study. This metabolite is more polar than the parent and therefore has reduced lipophilicity, additionally this metabolite contains an additional atom with three-dimensional geometry (a carbonyl group present in the parent is planar in nature, whereas the alcohol is not planar). A combination of reduced lipophilicity and also reduced planarity is associated with increased aqueous solubility which is an advantage for an oral drug molecule. Additionally, reducing lipophilicity is frequently associated with other superior developability properties for drug molecules including reduced potential to cause drug-drug interactions and reduced potential for toxicity.

Therefore, based on the above, it is herein noted that all compounds of Groups 1A are encompass by the following general formula:

wherein:

• • A represents a group selected from a C₁-C₄ alkyl (preferably a C₁-C₂ alkyl), an aryl such as a phenyl group, a heteroaryl and cyclic amides; wherein optionally any of these groups is substituted by 1, 2 or 3 groups that are independently selected from:
  •  a) halogen atom such as a chloride or a bromide atom, a hydroxyl, NO₂, —CN, —N(R^a)R^b, —OR′, —C(═O)R^a, —C(═O)OR^a, —C(═O)N(R^a)R^b, —OC(═O)—R^a, —N(R^c)C(═O)R^b, —NR^cSO₂R^a, —SO₂N(R^a)R^b, —SR^a, —S(O)R^a, —S(O)₂R^a;
  •  b) linear or branched C₁-C₆ alkyl, preferably a methyl group, optionally substituted by 1, 2 or 3 halogen atoms;
  •  c) C₃-C₆ cycloalkyl which optionally contains 1 or 2 heteroatoms selected from 0, S and N, and which ring is optionally substituted by C₁-C₃ alkyl;
  •  d) phenyl or C₅-C₆ heteroaryl each optionally substituted by halogen atom, cyano group, C₁-C₃ alkyl or cyclopropyl;
  • each R^a, R^b and R^c independently represented:
  •  a) hydrogen atom,
  •  b) linear or branched C₁-C₁₂ alkyl preferably a methyl group, C₃-C₆ cycloalkyl and C₄-C₆ heterocycloalkyl, which were optionally substituted by 1, 2 or 3 substituents selected from a carbonyl group, halogen atom, hydroxy, phenyl, C₃-C₆ cycloalkyl, linear or branched C₁-C₆ alkoxy, amino, alkylamino, dialkylamino, linear or branched C₁-C₆ alkylcarbonyl,
  •  c) phenyl or C₅-C₆ heteroaryl group, which were optionally substituted by 1, 2 or 3 substituents selected from halogen atom, cyano group, linear or branched C₁-C₆ alkyl, linear or branched C₁-C₆ haloalkyl, hydroxy, linear or branched C1-C6 alkoxy, amino, alkylamino, dialkylamino;
  •  d) R^a and R^b form together with the nitrogen atom to which they were attached, a 3- to 8 membered ring which optionally contained a further heteroatom selected from O, N and S, and which ring was optionally substituted by 1, 2 or 3 substituents selected from carbonyl group, linear or branched C₁-C₆ alkyl, linear or branched C₁-C₆ haloalkyl, linear or branched C₁-C₆ alkylcarbonyl;
  • x and y were integers independently selected from 0 and 1;
  • each R¹ and R² independently represented a group selected from hydrogen, aryl such as a phenyl group, cyclopropyl or linear or branched C₁-C₆ alkyl;
  • z was an integer selected from 0, 1, 2 or 3;
  • R³ represented a group selected from a halogen atom such as a chloride atom, —CN, cyclopropyl, —OR^a, or linear or branched C₁-C₆ alkyl, said alkyl can optionally be substituted by 1, 2 or 3 halogen atoms; wherein the group R³, if present, replaces the hydrogen atom of one of the groups CH present in the phenyl ring to which R³ is attached;

as well as any solvates, isomers or pharmaceutically acceptable salts thereof.

Thus, a first aspect of the present invention refers to compounds of formula II. Preferred compounds are selected from the following list consisting of:

or a solvate, an isomer or a pharmaceutically acceptable salt thereof.

In addition, it is herein noted that all compounds of Groups 3A are encompass by the following general formula:

wherein:

• • A represented a group selected from Hydrogen and C₁-C₄ Alkyl optionally substituted by 1, 2 or 3 groups that were independently selected from:
  •  a) halogen atom, NO₂, —CN, —N(R^a)R^b, —OR^a, —C(═O)R^a, —C(═O)OR^a, —C(═O)N(R^a)R^b, —OC(═O)—R^a, —N(R^c)C(═O)R^b, —NR^cSO₂R^a, —SO₂N(R^a)R^b, —SR^a, —S(O)R^a, —S(O)₂R^a;
  •  b) linear or branched C₁-C₆ alkyl preferably a methyl group, optionally substituted by 1, 2 or 3 halogen atoms;
  •  c) C₃-C₆ cycloalkyl which optionally contains 1 or 2 heteroatoms selected from 0, S and N, and which ring is optionally substituted by C₁-C₃ alkyl;
  •  d) phenyl or C₅-C₆ heteroaryl each optionally substituted by halogen atom, cyano group, C₁-C₃ alkyl or cyclopropyl;
  • each R^a, R^b and R^c independently represented:
  •  a) hydrogen atom,
  •  b) linear or branched C₁-C₁₂ alkyl preferably a methyl group, C₃-C₆ cycloalkyl and C₄-C₆ heterocycloalkyl, which were optionally substituted by 1, 2 or 3 substituents selected from a carbonyl group, halogen atom, hydroxy, phenyl, C₃-C₆ cycloalkyl, linear or branched C₁-C₆ alkoxy, amino, alkylamino, dialkylamino, linear or branched C₁-C₆ alkylcarbonyl,
  •  c) phenyl or C₅-C₆ heteroaryl group, which were optionally substituted by 1, 2 or 3 substituents selected from halogen atom, cyano group, linear or branched C₁-C₆ alkyl, linear or branched C₁-C₆ haloalkyl, hydroxy, linear or branched C₁-C₆ alkoxy, amino, alkylamino, dialkylamino;
  •  d) R^a and R^b form together with the nitrogen atom to which they were attached, a 3- to 8 membered ring which optionally contained a further heteroatom selected from O, N and S, and which ring was optionally substituted by 1, 2 or 3 substituents selected from carbonyl group, linear or branched C₁-C₆ alkyl, linear or branched C₁-C₆ haloalkyl, linear or branched C₁-C₆ alkylcarbonyl;
  • y is 0 or 1;
  • B is a nitrogen or oxygen atom
  • R¹ is only present when B is a nitrogen atom and is represented by a group selected from hydrogen, cyclopropyl or linear or branched C₁-C₆ alkyl, wherein said alkyl was optionally substituted by 1, 2 or 3 halogen atoms;
  • when y was 0, then 2 or 3 carbon atoms of R¹ can form a 5- or 6-membered ring together with the neighboring nitrogen atom and the 2 adjacent carbon atoms of the aromatic ring to which the nitrogen is attached;
  • each R² and R³ independently represented a group selected from hydrogen, cyclopropyl or linear or branched C₁-C₆ alkyl; optionally R² and R³ can form a 3- or 4-membered spiro ring together with the carbon atom to which they are both attached;
  • z was an integer selected from 0, 1, 2 or 3;
  • R⁴ represented a group selected from —CN, cyclopropyl or linear or branched C₁-C₆ alkyl, said alkyl was optionally substituted by 1, 2 or 3 halogen atoms; wherein the group R⁴, if present, replaces the hydrogen atom of one of the groups CH presents in the phenyl ring to which R⁴ is attached;

as well as any solvates, isomers or pharmaceutically acceptable salts thereof.

Thus, a second aspect of the present invention refers to compounds of formula III. Preferred compounds are selected from the following list consisting of:

or a solvate, an isomer or a pharmaceutically acceptable salt thereof.

It is further noted that additional compounds, with a structure similar to those falling within formula III, may also be encompass by such general formula:

if a 6 or 7 carbon atoms ring is created or formed between A or R1 and either R2 or R3. A compound illustrating such modification is illustrated below as compound K33:

In addition, it is herein noted that all compounds of Groups 2A are encompass by the following general formula:

wherein:

• • A represented a group selected from hydrogen, C₁-C₄ Alkyl, aryl, heteroaryl and cyclic amides, wherein the C₁-C₄ Alkyl preferably a C₁ alkyl, aryl, heteroaryl and cyclic amides are optionally substituted by 1 or 2 groups that were independently selected from:
  •  a) halogen atom, NO₂, —CN, —N(R^a)R^b, —OR^a, —C(═O)R^a, —C(═O)OR^a, —C(═O)N(R^a)R^b, —OC(═O)—R^a, — N(R^c)C(═O)R^b, —NR^cSO₂R^a, —SO₂N(R^a)R^b, —SR^a, —S(O)R^a, —S(O)₂R^a;
  •  b) linear or branched C₁-C₆ alkyl preferably a methyl group, optionally substituted by 1, 2 or 3 halogen atoms;
  •  c) C₃-C₆ cycloalkyl which optionally contains 1 or 2 heteroatoms selected from 0, S and N, and which ring is optionally substituted by C₁-C₃ alkyl;
  •  d) phenyl or C₅-C₆ heteroaryl each optionally substituted by 1 halogen atom, cyano group, C₁-C₃ alkyl or cyclopropyl;
  • each R^a, R^b and R^c independently represented:
  •  a) hydrogen atom,
  •  b) linear or branched C₁-C₁₂ alkyl, C₃-C₆ cycloalkyl and C₄-C₆ heterocycloalkyl, which were optionally substituted by 1, 2 or 3 substituents selected from a carbonyl group, halogen atom, hydroxy, phenyl, C₃-C₆ cycloalkyl, linear or branched C₁-C₆ alkoxy, amino, alkylamino, dialkylamino, linear or branched C₁-C₆ alkylcarbonyl,
  •  c) phenyl or C₅-C₆ heteroaryl group, which were optionally substituted by 1, 2 or 3 substituents selected from halogen atom, cyano group, linear or branched C₁-C₆ alkyl, linear or branched C₁-C₆ haloalkyl, hydroxy, linear or branched C₁-C₆ alkoxy, amino, alkylamino, dialkylamino;
  •  d) R^a and R^b form together with the nitrogen atom to which they were attached, a 3- to 8 membered ring which optionally contained a further heteroatom selected from O, N and S, and which ring was optionally substituted by 1, 2 or 3 substituents selected from carbonyl group, linear or branched C₁-C₆ alkyl, linear or branched C₁-C₆ haloalkyl, linear or branched C₁-C₆ alkylcarbonyl;
  • x and y were integers independently selected from 0 and 1;
  • R¹ represented a group selected from hydrogen, cyclopropyl or linear or branched C₁-C₆ alkyl, wherein said alkyl was optionally substituted by 1, 2 or 3 halogen atoms;
  • when y was 0, then 2 or 3 carbon atoms of R¹ can form a 5- or 6-membered ring together with the neighboring nitrogen atom and the 2 adjacent carbon atoms of the aromatic ring to which the nitrogen is attached;
  • each R² and R³ independently represented a group selected from hydrogen, cyclopropyl or linear or branched C₁-C₆ alkyl; optionally R² and R³ can form a 3- or 4-membered spiro ring together with the carbon atom to which they are both attached;
  • z was an integer selected from 0, 1, 2 or 3;
  • R⁴ represented a group selected from —CN, cyclopropyl, a halogen such as chloride atom or linear or branched C₁-C₆ alkyl, said alkyl was optionally substituted by 1, 2 or 3 halogen atoms; wherein the group R⁴, if present, replaces the hydrogen atom of one of the groups CH present in the phenyl ring to which R⁴ is attached;

as well as any solvates, isomers or pharmaceutically acceptable salts thereof.

Thus, a third aspect of the present invention refers to compounds of formula IV. Preferred compounds are selected from the following list consisting of:

or a solvate, an isomer or a pharmaceutically acceptable salt thereof.

Lastly, we herein provide still further analog/metabolite useful in the invention described in PCT/EP2019/081522. These analogs fall within the following general structure (V):

wherein n is an integer selected from 0 to 4, and A represents an aryl, preferably a phenyl, or heteroaryl optionally substituted by 1 or 2 groups that were independently selected from:

• •  a) halogen atom, NO₂, —CN, —N(R^a)R^b, —OR′, —C(═O)R^a, —C(═O)OR^a, —C(═O)N(R^a)R^b, —OC(═O)—R^a, —N(R′)C(═O)R^b, —NR^cSO₂R^a, —SO₂N(R^a)R^b, —SR^c, —S(O)R^a, —S(O)₂R^a;
  •  b) linear or branched C₁-C₆ alkyl preferably a methyl group, optionally substituted by 1, 2 or 3 halogen atoms;
  •  c) C₃-C₆ cycloalkyl which optionally contains 1 or 2 heteroatoms selected from 0, S and N, and which ring is optionally substituted by C₁-C₃ alkyl;
  •  d) phenyl or C₅-C₆ heteroaryl each optionally substituted by 1 halogen atom, cyano group, C₁-C₃ alkyl or cyclopropyl;
  • each R^a, R^b and R^c independently represents:
  •  a) hydrogen atom,
  •  b) linear or branched C₁-C₁₂ alkyl, C₃-C₆ cycloalkyl and C₄-C₆ heterocycloalkyl, which were optionally substituted by 1, 2 or 3 substituents selected from a carbonyl group, halogen atom, hydroxy, phenyl, C₃-C₆ cycloalkyl, linear or branched C₁-C₆ alkoxy, amino, alkylamino, dialkylamino, linear or branched C₁-C₆ alkylcarbonyl,
  •  c) phenyl or C₅-C₆ heteroaryl group, which were optionally substituted by 1, 2 or 3 substituents selected from halogen atom, cyano group, linear or branched C₁-C₆ alkyl, linear or branched C₁-C₆ haloalkyl, hydroxy, linear or branched C₁-C₆ alkoxy, amino, alkylamino, dialkylamino;
  •  d) R^a and R^b form together with the nitrogen atom to which they were attached, a 3- to 8 membered ring which optionally contained a further heteroatom selected from O, N and S, and which ring was optionally substituted by 1, 2 or 3 substituents selected from carbonyl group, linear or branched C₁-C₆ alkyl, linear or branched C₁-C₆ haloalkyl, linear or branched C₁-C₆ alkylcarbonyl;

A preferred compound is illustrated herein below as K8:

Compound K8 can be synthesized as illustrated below.

Synthesis of K8

In a preferred embodiment, the “compounds of the invention” useful to work the present invention are selected from those encompassed by any of formulae II, III, IV, or V above, or from the list of compounds explicitly indicated above (with their chemical structures) as structures pertaining to group 1A, 2A, 3A or the derivative of compound #1 (MKH1) or any further analogs thereof described throughout the present invention.

Most of the compounds of the invention can be easily synthesized as indicated in example 1.

The compounds of the invention can be in a free form or in the form of a pharmaceutically acceptable salt. Examples of pharmaceutically acceptable salts include inorganic acid salts such as hydrochloride, sulfate, nitrate, phosphate or hydrobromide, etc., organic acid salt such as acetate, fumarate, oxalate, citrate, methanesulfonate, benzenesulfonate, p-toluenesulfonate or maleate, etc. Also, when the compound has a substituent such as carboxyl group, there may be mentioned a salt with a base (for example, alkali metal salt such as sodium salt, potassium salt, etc. or alkaline earth metal salt such as calcium salt, etc.).

The compounds of the invention or their isomers, preferably enantiomers, or pharmaceutically acceptable salts can be in any of its intramolecular salt or adduct, or its solvates or hydrates.

The compounds of the invention can be, as taught by the present invention, use in therapy. In this sense, when the compounds of the invention or a pharmaceutically acceptable salt thereof is used as an effective ingredient for medical use, it can be used with a pharmaceutically acceptable carrier. A pharmaceutically acceptable carrier is an inert carrier suitable for each administration method and can be formulated into conventional pharmaceutical preparation (tablets, granules, capsules, powder, solution, suspension, emulsion, injection, infusion, etc.). As such a carrier, there may be mentioned, for example, a binder (such as gum arabic, gelatin, sorbitol and polyvinylpyrrolidone), an excipient (such as lactose, sugar, corn starch and sorbitol), a lubricant (such as magnesium stearate, talc and polyethylene glycol), a disintegrator (such as potato starch) and the like, which are pharmaceutically acceptable. When they are used as an injection solution or an infusion solution, they can be formulated by using distilled water for injection, physiological saline, an aqueous glucose solution.

The administration method of the compounds of the present invention and/or a pharmaceutically acceptable salts thereof of the present invention is not particularly limited, and a usual oral or parenteral administration method (intravenous, intramuscular, subcutaneous, percutaneous, intranasal, and as others, transmucosal, enteral, etc.) can be applied.

The dosage of the compounds of the present invention or a pharmaceutically acceptable salts thereof of the present invention may be optionally set in a range of an effective amount sufficient for showing a pharmacological effect, in accordance with the potency or characteristics of the compound to be used as an effective ingredient. The dosage may vary depending on administration method, age, body weight or conditions of a patient.

Lastly, a fourth aspect of the invention refers to a compound of any of formula (II), (Ill), (IV), or (V) or any further derivative of compound #1 (such as MKH1) described herein, or any pharmaceutically acceptable salts thereof; for use in the treatment of cancer. Preferably, for use in the treatment of a carcinoma. More preferably, wherein the cancer is a carcinoma selected from the list consisting of tumors arising from epithelial layers of the gastrointestinal track including month (oral cancer), esophagus, stomach, and small and large intestines (such as rectal or colon cancer), skin cancer, mammary gland (breast cancer), pancreas cancer, lung cancer, head and neck cancer, liver cancer, ovary cancer, cervix cancer, uterus cancer, gallbladder cancer, penile cancer, and urinary bladder cancer (such as renal, prostate or bladder cancer).

The following examples are merely illustrative of the present invention and do not limit the same.

EXAMPLES

Example 1. Synthesis

The of compounds of any of formula (II), (Ill), or (IV), or the derivative of compound #1, listed through-out the present specification can be prepared following the general synthetic route below, which is a modification of the general method described by V. V. Zarubaev et al./Bioorg. Med. Chem. 18 (2010) 839-848:

Example 2

2.1. Materials and Methods

Protein and ligands models. The X-ray crystal structure of the phosphotyrosine-binding domain of Hakai (PDB 3VK6) was downloaded from the Protein Data Bank and the dimer modelled using the proper symmetry operations. Amino acid protonation was carried out using the pdb2pqr server at a pH of 7.2. 3D models for the ligands were built using the Virtual Screening and Data Management Integrated Platform (VSDMIP), as described elsewhere. Briefly, the initial 3D coordinates for each ligand were generated with CORINA [Sadowski, J.; Gasteiger, J.; Klebe, G. Comparison of Automatic Three-Dimensional Model Builders Using 639 X-Ray Structures. J. Chem. Inf. Cornput. Sci. 1994, 34, 1000-1008 (DOI: 10.1021/ci00020a039)]. Thereafter, ALFA [4] was used to generate a large variety of conformers for each of which MOPAC-calculated atomic partial charges were assigned by employing the AM1 semiempirical model and the ESP method. All ligand models were stored in the VSDMIP database to be used in the different virtual screening campaigns.

Virtual Screening. Ligands in the eMolecules catalogue [https://www.emolecules.com/info/products-screening-compounds.html] were downloaded and processed as described in the preceding section. Only molecules presenting a carboxylic acid moiety and/or a phosphate group capable of mimicking a phosphotyrosine residue were considered. Next, CRDOCK was used to lodge the selected molecules inside the binding pocket of Hakai by using the CRScore scoring function and the BFGS energy minimizer. The ligands were then ranked according to the predicted score and the top 350 molecules were re-evaluated by using an in-house implementation of the HYDE scoring function. Finally, the best 20 molecules were visually inspected to select a final set of 6 molecules.

Binding pocket analysis. To better analyse the results of the virtual screening campaign, we used our in-house cGRILL software [6] to produce affinity maps within the binding pocket of Hakai's phosphotyrosine-binding domain based on the van der Waals, Coulombic and hydrogen bonding interactions of hypothetical atomic probes. The negatively charged acceptor probe (═O) was used to map possible locations for the molecular recognition of the phosphotyrosine residue to help filtering the docking solutions during the visual inspection of the poses.

Plasmids, inhibitors and antibodies pcDNA-Flag-Hakai, pBSSR-HA-ubiquitin, pSG-v-Src and pcDNA-myc-E-Cadherin plasmids were previously described. Compounds Hakin-1 [4-(5-[2-(4-nitrophenyl)-2-oxoethyl]thiol-1H-tetrazol-1-yl)benzoic acid] and Hakin-5 [(2E,4E,8E)-7,13-Dihydroxy-4,8,12-trimethyl-2,4,8-tetradecatrienoic acid] were obtained from ChemBridge Corporation and TimTec or Analyticon Discovery, respectively. The rest of the analogues tested (Ketophenyls A-1, A-7, A-8, A-9; ketoheteroaryls: A-23, A-25; Cyclic amides: A-10, A-16 and Bencylamide: A-6.1) were obtained from Vitasmlab. Compounds were re-suspended in DMSO (Sigma) at 100 mM for in vitro assays, and Hakin-1 was at 100 mM for in vivo assays. The highest concentration of DMSO was used as the vehicle control for the experiments. Note that Hakin-5 chemical structure is in FIG. 1.

Cell Culture

MDCK, HEK293T, HepG2, MCF7 and ACHN cells were cultured in Dulbecco's Modified Eagles Medium (DMEM). MDCK stably expressing Hakai cells (Hakai-MDCK) were previously reported and were growth in DMEM with G418 (800 μg/ml). Different clones of Hakai-MDCK cells shown comparable phenotypes and characteristics as demonstrated previously. LoVo and PC-3 cells were cultured in F-12K Medium (Kaighn's Modification of Ham's F-12 Medium) and HT-29 and HCT116 cells in McCoy's 5a Medium Modified. 5637 cells were cultured in RPMI medium. All culture media were supplemented with 1% penicillin/streptomycin and 10% of heat-inactivated fetal bovine serum (FBS) at 37° C. in a humidified incubator with 5% CO2. Cells were monthly tested for mycoplasma contamination and used only for 1-3 months after defrosted. LoVo and HT29 cells were authenticated with the StemElite ID system (Promega). For phase-contrast images, culture cells were photographed with a Nikon Eclipse-TI microscope.

Ubiquitination Assays

For ubiquitination assays, 750.000 HEK293T cells were seeded in 6-well cell culture plates and after 24 h were transfected with 0.25 μg Src, 0.75 μg Flag-Hakai, and 0.5 μg HA-ubiquitin with Lipofectamin 2000 (Invitrogen, UK). Six hours after transfection cells were treated with indicated concentrations of Hakin-1, Hakin-5 or the rest of the compounds tested for 36 h. Whole cell extracts were obtained in lysis buffer (20 mM Tris-HCl pH 7.5, 150 mM NaCl and 1% Triton X-100) containing 10 μg/ml leupeptin, 10 μg/ml aprotinin and 1 mM phenylmethanesulphonyl fluoride (PMSF), supplemented with 10 mM N-ethylmaleimide. Cells were harvested and subjected to western blotting using anti-HA antibody to detect ubiquitination.

Immunoprecipitation

For immunoprecipitation experiments, 293 cells were transfected with 3 μg Src, 4 μg Flag-Hakai, and 2 μg HA-ubiquitin and 3 μg E-cadherin with Lipofectamin 2000 (Invitrogen, UK). 24 h after transfection, cells were lysed for 20 min in 1 ml of 1% Triton X-100 lysis buffer (20 mM Tris-HCl pH 7.5, 150 mM NaCl and 1% Triton X-100) containing 10 μg/ml leupeptin, 10 μg/ml aprotinin and 1 mM phenylmethanesulphonyl fluoride (PMSF), supplemented with 10 mM N-ethylmaleimide and 2.5 mM sodium orthovanadate. After centrifugation at 18.000 g for 10 min, the supernatants were immunoprecipitated for 2 h with 2 μg of anti-E-cadherin antibody bound to 60 μl of protein G PLUS-Agarose beads, followed by SDS-polyacrylamide gel electrophoresis (PAGE) and western blotting with the indicated antibodies as previously reported.

Viability Assays

For cytotoxicity assays, 1×10⁴ cells were seeded per well into a 96-well plate. After 24 h cells were treated with the indicated inhibitors for 72 h and a MTT colorimetric cell viability assay was performed following manufacturer's instructions (Sigma Aldrich, St Louis, Mo.). Absorbance was measured at 570 and 630 nm using a Multiskan Plus Reader (Nanoquant Infinite M200 Tecan Trading AG, Switzerland). Dose-response curves were designed with Graph Pad Prism Software and the half-maximal inhibitory concentration (IC₅₀) values were calculated. Represented data are the mean±SEM of at least three independent experiments with six replicates per condition.

Western Blotting and Immunofluorescence

For western blot analysis, cells were treated with the indicated inhibitors for 48 h and the whole cell extracts were obtained as described previously. Twenty micrograms of lysates were resolved on a 10% polyacrilamide SDS-PAGE followed by western blot analysis performed as previously described. For immunofluorescence assays cells were grown for 24 h on glass coverslips and treated with the indicated inhibitors for 48 h. Cells were fixed with 4% PFA for 15 min, permeabilized with 0.5% Triton X-10 and incubated with E-cadherin antibody for 2 h. Coverslips were incubated with fluorescein-tagged secondary antibody (Dakopatts, Sweden) for 1. Finally coverslips were mounted with ProLong Gold antifade reagent (LifeTech, UK) and images were taken in epifluorescence microscope (Olympus) using 40× objective. Immunofluorescence of E-cadherin and DNA content analysis for FIGS. 22-23 were performed culturing of HT-29 human colorectal adenocarcinoma cell line in 384-well plates with densities of 3,000 cells per well in a total volume of 25 μl. After the completion of the staining, four images (2×2 array) of each well were taken with Vala Sciences' SIM™ with a 20× objective. Each image was acquired as a SIM Synthetic Focus with a z-stack range of 6 μm with 1 μm steps. The SIM Synthetic Focus feature will compile a “best focus” images from multiple images. One set of SIM Synthetic Focus images were taken in the DAPI channel for Hoechst 33342 staining, and another set of images were taken in the FITC channel for anti-E-cadherin-AlexaFluor488 labeling and analysed by Structured Illumination Microscopy (SIM™) platform to image the cells and Vala's CyteSeer® Cell-Cell Junction Algorithm to quantify the degree of expression and intracellular location of E-cadherin Vala's CyteSeer® Software can also measure relative DNA content by analyzing Total Integrated Intensity (TII) of the Nuclear Image (Ni) on the Nuclear Mask (Nm). This analysis was performed by Vala Science. Twenty compounds from were assayed in a “blinded” manner, at 2 test concentrations in 6 replicate wells for first assay and 3 replicate for second assay.

Proliferation Assays

For BrdU assays, 1×10⁴ of indicated cells were plated per well into a 96-well plate. After 24 h, cells were treated with the indicated inhibitors for 48 h. Three independent experiments were plated with six replicates per each condition. Cells were treated with 10 mM BrdU for 2 h. BrdU incorporation into newly synthesized DNA was measured using a cell proliferation colorimetric immunoassay kit according to the manufacturer's instructions (Roche, Switzerland). Results are expressed as mean±S.D. Results are represented as percentage of positive cells (mean±S.D) of three independent experiments.

Soft Agar-Colony Formation Assay

Soft agar-colony formation assay was performed on 12-well plates in triplicates at a density of 5×10³ MDCK and MDCK-Hakai cells/well, or 12×10³ HT29 cells/well. Cells were seeded in medium with 0.5% low-melting agarose over a layer with 0.75% low-melting agarose (Lonza Rockland, Me., USA). Cells were treated with the indicated inhibitors and DMSO was used as vehicle. Treatment was refreshed every 3 days and, after 21 days for MDCK and MDCK-Hakai cells or 28 days for HT29 cells, number of colonies were quantified. Quantification of five randomly-selected fields of each condition was photographed with a Nikon Eclipse-TI microscope (objective 4×). Experiments were conducted with three triplicates and were repeated three times. Data are represented as mean±SD.

Migration and Invasion Assay

For invasion assays, cells were treated with Hakin-1 or DMSO as vehicle for 48 h using 1% FBS during the last 24 hours. 3×10⁵ MDCK, MDCK-Hakai or LoVo cells were seeded in a cell invasion chamber (Cell invasion assay kit, Chemicon International) containing medium with 2% FBS. After 72 hours for MDCK and MDCK-Hakai Invasive and 16 h for LoVo cells, invasive cells invaded that reach the lower chamber containing 30% FBS were fixed and stained with crystal violet (Sigma Aldrich, St Louis, Mo.) following the manufacturer's specifications. For migration assays, HT29 cells were cultured with Hakin-1 or DMSO as vehicle for 48 h, using medium without serum the last 24 h. In the cell migration chamber were seeded 3×10⁵ HT29 cells (Cell migration kit, Millipore, Bedford, Mass.) containing medium without serum. After 16 h, migrated cells in the lower chamber containing serum with 30% FBS were stained with crystal violet and counted following the manufacturer's specifications. For both invasion and migration assays cells were counted in five fields photographed with an Olympus microscope using a 20× objective, experiments were performed in triplicates for each condition and the assays were repeated at least three times. Results are expressed as mean±SD.

Tumour Xenograft Model

Xenografts experiments were performed in Experimental Surgery Unit—Technological Training Center from INIBIC in compliance with the European Community Law (86/609/EEC) and the Spanish law (R.D. 53/2013). The experiment was approved by the Ethics Committee for Animal Experimentation of Xerencia de Xestion Integrada da Coruna (XXIAC). Mice were in a 12/12 hours light/dark cycle with water and food available ad libitum. Six weeks old athymic nu/nu mice were randomly distributed in groups. One million of MDCK cells, resuspended in DMEM without serum and antibiotic, were subcutaneously inoculated in both flanks in two groups of 3 animals. The same number of Hakai-MDCK cells were injected in two groups of 4 animals. Twenty days after inoculation tumours in Hakai-MDCK were palpable. Then, half of the animals were treated with Hakin-1 (5 mg/kg) and the other half with the same concentration of DMSO every 3 days. Tumour outgrowth was monitored twice a week taking measurements of tumour length (L) and width (W) with an electronic calipter. Tumour volume was calculated as pLW2/6. Forty days after inoculation, animals were sacrificed. Tumours, lungs, kidneys and livers were collected and fixed in 4% PFA and embedded in paraffin blocks for histology and/or immunohistochemistry (IHC) analyses.

Histology and Immunohistochemistry

Tumours and tissues were deparaffinised, rehydrated and stained with haematoxylin and eosin (H&E) as previously described. Tumour sections (4 μm) were also deparaffinised and hydrated for immunohistochemistry. Antigen retrieval was carried by heating the samples (2100 Retriever; PickCell Laboratories) in citrate buffer (Dako REAL, Denmark) or in EDTA buffer. Then, endogenous peroxidase activity was blocked with peroxidase blocking (DakoCytomation, Denmark). Samples were blocked and permeabilized with 0.2% BSA and 0.1% Tx-100 for 1 hour and incubated with the indicated primary antibodies overnight at 4° C. in a wet chamber. Slides were incubated for 1 hour at room temperature with the secondary antibody and detection was carried our using DAB (DakoReal Envision kit) according to manufacturer instructions. Finally, nuclei were counterstained with Gill's Hematoxylin and mounted with DePeX. Pictures were taken with an Olympus microscope. Quantification of images was performed taken 5 photographs of each animal with Image J programme and the represented results are shown as mean±SEM. The number of mitosis was counted in sections stained with H&E. In this case, ten pictures of each tumour were taken with an Olympus BX50 microscope (objective 40×) and the number of mitosis was counted manually. Results are represented as mean±SEM and a representative photograph is shown for each condition.

Quantification of Lung Metastasis from In Vivo Mouse Model

Real-time PCR was used to study the presence of metastasis in the lung mice. Primers for HA epitope and Hakai present in ectopic HA-tagged Hakai expressed in MDCK-Hakai cells (5′-TCTGGGACGTCGTATGGGTA-3′; 5″-TTCTTCATCACCTTGCGGG-3′) were used for the quantification. Primers for mouse apolipoprotein B (apob) (5′-CGTGGGCTCCAGCATTCTA-3′; 5′-TCACCAGTCATTTCTGCCTTTG-3′) were used as endogenous control. MDCK cell line was used as negative control. Lung DNA was extracted from 10-15 sections of paraffin blocks (4 μm) using with QIAamp DNA Mini Kit (Qiagen). The amplification and quantification of DNA was carried by quantitative PCR in technical triplicates by using a LightCycler 480 real-time lightcycler (Roche). Relative DNA levels were calculated by 2^−ΔΔCt method.

In Vivo TUNEL Assay

Tissue sections from tumours were deparaffinised and rehydrated using standard protocols. The slides were rinsed twice with PBS and treated with citrate buffer buffer (Dako REAL, Denmark) in microwave at 350 W for 5 min. The tissue sections were then analysed with an in situ Cell Death Detection Kit, Fluorescein (Roche) following the manufacturer's instructions. Then, slides were incubated with Hoechst for 5 min in darkness. The reaction was visualized under an epifluorescence Olympus microscope using 20× objective. Five representative pictures of each section were taken. The percentage of positive cells was calculated and results are represented as mean±SEM.

Hepatocyte Stability

Test compound (final substrate concentration 3 μM; final DMSO concentration 0.25%) were pre-incubated at 37° C., prior to the addition of a suspension of cryopreserved hepatocytes (final cell density 0.5×106 viable cells/mL in Williams E media supplemented with 2 mM L glutamine and 25 mM HEPES) to initiate the reaction. The reactions were stopped with acetonitrile containing internal standard at the appropriate time points (0, 10, 20, 40, 60 and 120 min). The termination plates were centrifuged at 2500 rpm at 4° C. for 30 minute to precipitate the protein. Following the hepatocyte stability assays, the samples were utilized for metabolite profiling. Hepatocyte stability in mouse and human was performed by using the incubation of tested compound (3 μM) with cryopreserved hepatocytes in suspension. Samples were removed at 6 time points over the course of a 60 min experiment and remaining test compound at each time point was analysed by using LC-MS/MS. Then, data was analysed and an intrinsic clearance (CLint) with standard error and half-life (t½) reported.

Metabolite Profiling

The samples from the hepatocyte stability assay were utilized for metabolite profiling. The 10 and 20 minute samples were compared to the 0 minute control sample to identified the metabolites formed. The metabolites have been displayed as extracted ion chromatograms (XIC) and the representative mass spectra. The areas and percentages reported for the parent and metabolites have been calculated using the XIC data; it has been assumed that each metabolite has the same ionization efficiency and that the sensitivity of the metabolite has not been affected by the biotransformation. The m/z found for each metabolite in each species, and its associated ppm error, have been displayed for each species from the time point showing the largest peak area. For accuracy, a ppm error of less than 5 is desirable; when the response for a metabolite observed is low the ppm error maybe greater than 5. Where a metabolite has been referred to as a potential oxidation it can refer to a potential hydroxylation, epoxidation or oxide formation. Representative collision induced dissociation (CID) mass spectra were obtained for the metabolites found. Structural elucidation was then performed on the metabolite observed. The data are processed using Metabolynx XS (Waters Ltd). When the compound structure has been provided, the data is processed using mass defect filtering1 with the dealkylation tool2; if the structure is not provided then mass defect, filtering alone is used. Mass defect filtering uses the chemical feature that when compounds are metabolized, the mass defect (i.e. the fractional-part of the observed m/z) for the metabolite does not change significantly and hence drug related material can be differentiated from the endogenous material. The de-alkylation tool is used in addition to the mass defect filtering to take into account that when the molecule cleaves metabolically e.g. at an amine group, the mass defect may change. Following this initial processing, the data is compared to the control sample to determine whether a series of expected metabolites are observed. Finally, the same data set is processed, using 1 a.m.u. windows across the whole data acquisition range to look for non-predicted or unexpected metabolites. After the automated Metabolynx XS processing, the data are reviewed to confirm the validity of the detected metabolites and to ensure correct assignment of the metabolite observed. The elemental formula for the observed ion and compound is reported, along with the error in parts per million (ppm) for the measured ion compared to the theoretical mass of the ion. When structural elucidation has been performed, it is common that collision induced dissociation data do not give the exact position of a biotransformation. Therefore, structures are depicted in Markush format3 with the shaded area showing potential sites of modification. Hepatocyte stability, metabolic profiling and test compound analysis was performed by Cyprotex Discovery.

Statistical Analysis

Shapiro-Wilk test was used to check a normal distribution and Levene test to assess the equality of variances. Statistical significance of data was determined with ANOVA with Bonferroni test or Kruskal-Wallis with Tukey correction test. Significance among the experimental groups indicated in the figures is shown as * p<0.05, **p<0.01 and ***p<0.001. Results obtained are expressed as mean±SD or mean±SEM as indicated. Survival graphic in xenograft assay was analysed with GraphPad Prism software and the test of Breslow was used to calculate p values. Results are represented as fold induction of treated cells over the values obtained in the untreated cells. The data produced by CyteSeer's algorithm were analyzed in GraphPad Prism 5 using ANOVA, followed by Dunnett's post-hoc multiple comparisons test for statistical significance of each dose vs. the vehicle control. Abbreviations/notations: n.s., not significant; *, p<0.05; **, p<0.01; ***, p<0.001. In bar graphs, the bars represent means of 6 samples, while the error bars represent the standard deviation of the mean.

List of Antibodies Used to Carry Out the Present Invention.

Antibody	Dilution	Use	Catalog n°/provider
Hakai	1:1000	Western	Invitrogen 36-2800
	1:250	IHQ(P)	Invitrogen 36-2800
E-Cadherin	1:1000	Western	BDTrans Lab
			610182
	2 ug	IP	BD Trans Lab
			610182
	1:200	IF	BD Trans Lab
			610182
	1:400	IHQ(P)	Cell signaling
			243E10
Cortactin	1:1000	Western	Millipore 05-180
	1:50	IHQ(P)	Millipore 05-180
N-Cadherin	1:1000	Western	Abeam ab18203
	1:100	IHQ(P)	Abeam ab18203
Vimentin	1:1000	Western	Cell signalling
			D21H3
Ki67	1:150	IHQ(P)	Dako M7240
CD31	1:100	IHQ(P)	Abeam ab 28364
HA	1:1000	Western	Roche 12CA5
FLAG	1:4000	Western	Sigma Aldrich,
			Clone M (F1316S)
GAPDH	1:5000	Western	Invitrogen 39-8600
Vinculin	1:2000	Western	Cell Signaling
			E1E9V
HRP rabbit	1:5000	Western	GE healthcare
			NA934
HRP mouse	1:5000	Western	GE healthcare
			NA931
Mouse IgG	2 kg	IP	Santa Cruz
			Biotechnology
			sc-2025

2.2. Results

Identification of Putative Selective Hakai Inhibitors

With the aim of finding candidate molecules with the required potential to inhibit Hakai, we designed a virtual screening workflow based on the structural information available and the nature of the phosphotyrosine-binding pocket, which was explored with the aid of affinity probes. As a first step, we considered only molecules in our chemical library that display a negatively charged carboxylate or phosphate group that would be complementary to the highly positive molecular electrostatic potential of the binding pocket. The selected molecules were then docked into the Hakai dimer to evaluate all possible binding poses and then ranked using the HYDE postprocessing scoring function to estimate the interaction energy of the hypothetical Hakai-inhibitor complexes. The first 20 top-ranking molecules were visually inspected and two of them were selected for subsequent experimental validation, namely Hakin-1 and Hakin-5 (FIG. 1a). According to our binding mode model, the benzoate moiety present in Hakin-1 would be a surrogate of phosphotyrosine (FIG. 1b, upper panel). The carboxylate group is placed in an extremely favourable region for a negatively charged probe, as estimated by our affinity maps. This region is lined by residues Lys-126, Tyr-176, His-185 and Arg-189, while the phenyl ring would be sandwiched between the guanidinium, side-chains of Arg-174 and Arg-189. The rest of the molecule would be able to establish hydrogen bonds with the side chains of Arg-174 residues from both monomers and also the Gln-170 backbone while maintaining the required shape. Hakin-5 (FIG. 1b, lower panel), despite bearing a carboxylate group and presenting an equivalent number of potential groups for hydrogen bonding interactions, lacks a phenyl ring that could mimic a phosphotyrosine.

Effect of Hakin-1 Inhibitor on Hakai-Induced Ubiquitination

We first investigated the effect of Hakin-1 inhibitor on the ubiquitination induced by the E3 ubiquitin-ligase Hakai by using culture tumour cells. 293T cells were transfected with Src, Hakai and ubiquitin in presence of Hakin-1 inhibitor or DMSO as control. Hakin-1 strongly reduces the ubiquitination mediated by Hakai in a doses dependent-manner (FIG. 1c) and no effect was seen in Hakai protein levels. However, Hakin-1 did not affect ubiquitination when Hakai was not overexpressed, confirming that Hakin-1 reduces the ubiquitination in a Hakai-dependent manner (FIG. 1d). Moreover, no effect was detected on Hakai-mediated ubiquitination when cells where treated in presence of another identified Hakai inhibitor by virtual screening, Hakin-5, (FIG. 1e), further supporting the specific effect of Hakin-1 on Hakai-induced ubiquitination. Finally, we observed a reduction of Hakai-dependent ubiquitination of E-cadherin complex when cells were treated with Hakin-1 (FIG. 1g. Collectively, our data show that Hakin-1 inhibits Hakai-mediated ubiquitination without affecting Hakai protein levels.

Hakai Inhibition by Hakin-1 Activates Epithelial Differentiation on Tumour Cells

Next, we studied the effect of Hakai inhibition on the cell viability of cancer cells. For this objective, we generated a dose-response curve by using Hakin inhibitors in several epithelial cells as we previously reported. First, we analysed the cytotoxicity effect on Hakin-1 on HT-29 and LoVo colon tumour cell lines showing an important inhibitory response (FIG. 2a). We extended our studies by using a normal epithelial MDCK cell line that has been extensively used as an in vitro model system to study EMT. As previously showed, Hakai overexpression in MDCK cells (Hakai-MDCK) induced a fibroblastic-like phenotype and a disappearance of E-cadherin-based cell-cell contacts. When treating these cell lines with Hakin-1 or Hakin-5 inhibitor, both clones tested of Hakai-MDCK cell lines were more sensitive to Hakin-1 and Hakin-5 treatment compared to normal epithelial MDCK that were more resistant (FIG. 2b). These results further suggest that Hakin-1 may be particularly effective against cancer cells on which Hakai is overexpressed, as it is seen in human colon cancer, where Hakai is highly increased in colon carcinoma compared to adjacent normal tissues. Given the previously reported role of Hakai on the epithelial-to-mesenchymal transition, we next analysed the effect of Hakin-1 on tumour cell phenotype. By phase contrast, we observed that both Hakin modestly induce an epithelial phenotype on HT-29 and LoVo cells, however, it is important to note that both cell lines already show an epithelial morphology (FIG. 2c). Moreover, we tested the effect of Hakin-1 and Hakin-5 inhibitors on the mesenchymal phenotype of Hakai-transformed MDCK cells. We observed an induction of an epithelial phenotype, increasing cell-cell contacts, accompanied with a reduction of protrusions formation. On the contrary, no effect was observed when treating epithelial MDCK cells with the specific inhibitors (FIG. 2d). Given the reported action of Hakai during EMT, by it molecular action on the E-cadherin ubiquitination, endocytosis and degradation, leading the alteration of cell-cell contacts, we further study the effect of Hakin-1 inhibitor on the reversion of EMT. As shown in FIG. 3a, by western-blotting we observed that Hakin-1 was able to increase E-cadherin levels in HT-29 cells, while the mesenchymal Vimentin marker was reduced. We also analysed the effect of Hakin-1 on Cortactin, another reported substrate for Hakai, confirming its effect on the increase expression levels. We also confirmed these results by using another epithelial tumour cells, LoVo cells (FIG. 3b). Moreover, as E-cadherin loss at cell-cell contacts is considered a hallmark of the EMT, we studied the expression of E-cadherin by immunofluorescence showing a significant increase E-cadherin levels at cell-cell contacts in HT-29 and LoVo cells (FIG. 3c). However, no effect by western-blotting or immunofluorescence was detected on E-cadherin protein levels when using Hakin-5 (FIG. 8). Finally, to test the effect of Hakin-1, mesenchymal Hakai-MDCK cells were also used. Hakai-MDCK cells did not express basal protein levels of E-cadherin, therefore no recovery was detected under Hakin-1 treatment. Taken together, these results show that Hakin-1 induces epithelial differentiation in different tumour epithelial cells, which is accompanied by a reduction of mesenchymal marker in vivo.

Hakin-1 Inhibits Proliferation, Oncogenic Potential and Invasion in Tumour Culture Cells

We next characterized the effect of Hakin-1 in tumour cell lines using standard proliferation and soft agar colony-forming assays. Given that Hakai affects not only cell-cell contacts but also proliferation in fibroblast and epithelial cells, we decided to determine the possible effect of Hakin-1 in cell proliferation. Hakin-1 reduced cell proliferation in HT29 and LoVo cell lines (FIG. 4a), although no effect was seen using Hakin-5 inhibitor (FIG. 4b), further supporting Hakin-1 antitumor action by its control on cell proliferation. We extended our analysis by using Hakai-MDCK cells compared to normal epithelial MDCK cells. As previously reported, we confirmed that Hakai-transformed MDCK cells strongly increased cell proliferation compared to normal MDCK cell (FIG. 4c). Interestingly, Hakin-1 was able to suppress proliferation in Hakai-MDCK cell while no effect was detected in non-transformed epithelial MDCK cells (FIG. 4c). Hakin-1 also inhibits cell proliferation in other epithelial cells lines such as breast cancer MCF7 cell, prostate cancer PC-3 cells, bladder cancer 5637 cells, liver cancer HepG2 cells and renal cancer ACHN cells (FIG. 9). These results suggest that Hakin-1 may function as antiproliferative agent when high levels of Hakai are expressed, such as it occurs in human adenocarcinoma. By using soft agar colony formation assays, we evaluated the effect of Hakin-1 in HT-29 and Hakai-MDCK tumour cell lines, showing a robust inhibition of colony formation in both cell lines (FIG. 4d). As we previously published, no colony formation was detected while treating MDCK non-transformed cells by Hakin-1. EMT process is characterized by the acquisition of migratory and invasive capabilities. We demonstrated that Hakin-1 strongly reduced cell invasion in LoVo cells (FIG. 5a). Moreover, while no cell invasion was detected in MDCK cells, Hakai overexpression induce the ability to invade in normal epithelial MDCK cells, and in these Hakai-MDCK cells Hakin-1 also decreased cell invasion (FIG. 5b). Finally, given that HT-29 cells were unable to invade under these experimental conditions, we tested Hakin-1 effect in cell motility, showing an important reduction of cell migration under Hakin-1 treatment (FIG. 5c). All these findings support an antitumor effect of Hakin-1 by acting on cell proliferation, oncogenic potential, cell motility and invasion.

In Vivo Antitumor Effect of Hakin-1 in Tumour Xenografts

The acquisition of migratory and invasive abilities during EMT are crucial events in the formation of distant metastasis, therefore targeting these events is therefore an ideal approach for cancer treatment. Since we have shown that Hakin-1 effectively inhibits cell proliferation, oncogenic potential and cellular invasion and motility in cell cultures, we decided to study the efficacy of Hakin-1 on this suppression of pre-existing tumours in vivo. For this purpose, MDCK and Hakai-MDCK cell were subcutaneously injected into the flank of nude mice. As previously reported, Hakai-MDCK cells formed primary tumours whereas parental MDCK cells were unable to do so. Hakin-1 displayed a potent effect on inhibiting xenograft tumour growth in vivo (FIG. 6a). Morphologically xenograft tumour cells exhibits undifferentiated and spindle-shape phenotype, large nucleus and a reduction of the cytoplasm size. This morphology was strongly altered by Hakin-1 treatment, showing an induction of tumour differentiation and an increase in cytoplasm size (FIG. 6b). Moreover, we found tumour-cell infiltration in blood vessels, whereas no infiltration was detected in Hakin-1 treated xenografts tumours (FIG. 6c). Furthermore, by analysing two proliferative markers, Ki67 and the mitotic index, it was shown that Hakin-1 markedly reduce the number of Ki67-positive cells and the mitotic-index (FIG. 6d-e), while no effect on apoptosis was detected (FIG. 10), further underscoring Hakin-1 effect on the inhibition of cell proliferation in vivo. We also visualized blood vessels in tumour sections by immunohistochemistry using CD31 angiogenic marker. A strong reduction on the number of blood vessels in Hakin-1 treated xenograft tumours compared to non-treated tumours was quantified indicating its inhibitory effect on angiogenesis (FIG. 6f). Interestingly, no damage was observed in lung and kidney tissues in Hakin-1 treated nude mice, showing a normal morphological structure, supporting that Hakin-1 treatment inhibits tumour growth in nude mice apparently without systemic toxicity (FIG. 11).

Hakin-1 Treatment Reduces N-Cadherin Mesenchymal Markers of Tumours Xenograft and Micrometastasis Formation in Lung In Vivo

We further evaluated the in vivo effect of Hakin-1 on the reversion of the EMT, as crucial process in tumour progression and cell invasion. First, we confirmed that Hakai protein expression levels were not affected by Hakin-1 action in xenograft tumours of nude mice (FIG. 7a), further supporting previous in vitro results where it was shown that Hakin-1 inhibited Hakai activity by its action on its ubiquitin-ligase activity without altering Hakai protein expression (FIG. 1). Given that that E-cadherin was completely disappeared in Hakai-MDCK cells, as expected, E-cadherin was not detected in Hakai-MDCK xenografts tumours in nude mice in presence or absence of Hakin-1 (FIG. 7b). However, when we studied the expression levels of the N-cadherin mesenchymal marker, another hallmark of the EMT, we found that N-cadherin expression was strongly reduced in tumour xenografts treated with Hakin-1 compared to DMSO treated mice (FIG. 7c). These data further support that Hakin-1 inhibits mesenchymal-type tumour cells, by a reduction of N-cadherin mesenchymal marker. Given that the best described target E-cadherin for Hakai was completely absent in Hakai-MDCK mesenchymal tumours, we also extended our study by analysing another described target for Hakai, Cortactin. Cortactin is a cytoskeleton protein and one of the major substrates for Src kinase. Interestingly, Cortactin expression was only detected in the cytoplasm of Hakai-MDCK xenograft tumours and its expression was recovered by Hakin-1 treatment (FIG. 7d), further supporting that Hakin-1 may inhibit the induction of the ubiquitination and degradation of Cortactin by Hakai. To determine whether Hakin-1 may impact on cancer metastasis, lung tissues from nude mice were analysed by H&E staining, however, distant metastasis was not detected under the experimental conditions (FIG. 7e). Therefore, in order to detect the possible presence of micrometastasis, we performed a quantitative PCR by analysing the presence of DNA of Hakai-MDCK in lung. For this purpose, HA-tagged Hakai present in Hakai-MDCK cells was measured by using two different specific primers: one designed for HA epitope and the second primer for Hakai. Hakin-1 caused a significant reduction of micrometastasis detected in lung of the Hakai-MDCK xenograft mice compared to the control DMSO treated mice, while no detection was found in lung of MDCK-injected mice (FIG. 7f). This result underscore that Hakin-1 inhibits the metastasis to lung in vivo.

Effect of Hakin-1 Analogues on Cytotoxicity and on Hakai-Induced Ubiquitination

Next, we studied the effect of the selected analogues on HT29 colon cancer cells. First, we analysed cytotoxicity effect of the following analogues: Ketophenyls A-1, A-7, A-8 and A-9; ketoheteroaryls: A-23 and A-25; Cyclic amides: A-10 and A-16 and Bencylamide A-6.1 on HT-29 colon tumour cell lines. It is shown an important inhibitory response of the Ketophenyls A-7, A-8, A-9 and ketoheteroaryls: A-23, A-25, however no cytotoxic effect was detected by the action of Ketophenyls A-1, Cyclic amides: A-10 and A-16 and Bencylamide A-6.1 (FIG. 12). Then, we investigated the effect of specific selected analogues on the ubiquitination induced by the E3 ubiquitin-ligase Hakai by using culture tumour cells. 293T cells were transfected with Src, Hakai and ubiquitin in presence of the specific analogue inhibitors or DMSO as control. An important reduction of the ubiquitination mediated by Hakai in a doses dependent-manner was observed by using Ketophenyls A-7 analogue (FIG. 13), showing an effect on the reduction of Hakai activity without affecting Hakai protein levels. On the other hand, analogue Ketophenyls A-9 reduced Hakai-mediated ubiquitination but reducing Hakai protein levels at the concentration tested. Moreover, cyclic amides: A-10 and A-16 modestly reduced the ubiquitination mediated by Hakai, without affecting protein levels. Finally, it was also detected an inhibitory effect of Hakai activity by the action ketoheteroaryls A-23, at a low concentration.

2.3. Further Results

Metabolite Profiling Report for Hakin-1 in Cryopreserved Hepatocytes

In the in vivo model, we observed a strong antitumor effect by using low concentration of Hakin-1 (5 mg/kg/three days per week), while the in vitro antitumor effect was observed using very high concentration (100-200 μM). Therefore, we decided to analyse whether an intermediate metabolite from Hakin-1 could be identified and be involved in the antitumor effect. In order to address this point, we carried out a metabolite profiling on the Hakin-1 in mouse-cryopreserved hepatocytes to determine whether any metabolite could be formed. Metabolite profiling for Hakin-1 was performed in mouse cryopreserved hepatocytes using 10 and 20-minute samples compared to 0 minute control sample. Identification of the metabolite of Hakin-1, named MKH1, can be found in Table 1 with expanded data in Table 2 to Table 3. Representative chromatograms and spectra for Hakin-1 and reported metabolites along with the proposed assignments for parent (Hakin-1) and metabolite (named as MKH1) can be found in (FIG. 15-19). Our results show that only one metabolite was identified in mouse hepatocyte sample and the structural elucidation and synthesis route has been provided for this metabolite (Table 1 and FIG. 20, respectively). Interestingly, only 5.99% of Hakin-1 remains in the mouse cryopreserved hepatocytes samples after 20 minutes compared to 0 minutes control sample (97.2%), while 94% of MKH1 appeared at 20 minutes compared to 0 minute control sample (2.72%). Then, we decided to determine the stability of Hakin-1 and the MKH1 in human and mouse-cryopreserved hepatocytes in order to compare their stability. The results indicate that half-life (T½) of Hakin-1 is 5.92 min in mouse, and 77.3% of this compound remains after 60 min in human (estimated half-life is 140 min). In the case of the metabolite (MKH1), the compound is stable after 60 min, indeed, around 95%-100% is still present in mouse and human species. These data indicate that the identified metabolite MKH1 was more stable than the Hakin-1 parental compound suggesting that MKH1 can be implicated in the antitumor effect observed in vivo.

Effect of New Selected Compounds on E-Cadherin Expression and Cell Cycle Analysis

Given the antitumor effect observed in vitro and in vivo of Hakin-1, we decided to select analogs with the aim to improve Hakin-1 potency and/or the efficacy. To do so, in collaboration with a medicinal chemist, several compounds were chosen according to the potential to form the same molecular interactions with the target protein but have novel structure (FIG. 21) and the effect on E-cadherin expression was analysed by immunofluorescence and quantified after 48 h treatment with each compound.

We firstly used HT-29 colon cancer line and analysed the effect of K1 and K2 on E-cadherin expression by Vala's Structured Illumination Microscopy platform to image the cells using Vala's CyteSeer® Cell-Cell Junction Algorithm to quantify the expression of E-cadherin at cell-cell contacts. As shown in FIG. 22A, a significant increased E-cadherin levels was seen by immunofluorescence for compounds K1 and K2. Quantification of the immunofluorescence images is included in FIG. 22B. The results indicate that K1 compound at 100 μM treatment significantly increased E-cadherin levels at cell-cell contacts compared to the DMSO vehicle control. Significant differences were also detected for K2 compound. As positive control we used nocodazole, a microtubule polymerization inhibitor, at 250, 500, or 1000 ng/ml for 24 hours that significantly increased E-cadherin expression levels by 32%, 42% and 47% (p<0.0001 for all three conditions (FIG. 23). Moreover, the effect of the compounds on cell cycle analyses was also analysed (FIG. 24). K1 and K2 compounds at 100 μM treatment at 48 hours arrested the cells in G0/G1 phase and therefore reduced the cell numbers (FIG. 24). As positive control nocodazole was used, showing a dramatic shift towards G2/M phase arrest, compared to DMSO vehicle control (FIG. 25). In summary, K1 and K2 are novel analogs that increase E-cadherin levels at cell-cell contacts and arrested the cells in G0/G1 phase compared to the DMSO control.

Then, the effect on E-cadherin expression of the identified metabolite of Hakin-1 (MKH1) was also studied by immunofluorescence showing a significantly increase expression of E-cadherin, even at a low concentrations (50 μM, 20 μM) (FIG. 26). Moreover, K8 and K33 were also tested by immunofluorescence (FIG. 27-28). Our results indicate that K8 and K33 increase E-cadherin levels at cell-cell contacts compared to the DMSO vehicle control (FIG. 27-28, respectively). K1 was included as positive control. In FIG. 29, we show that MKH1 and K8 compounds inhibit cell proliferation in human colon cancer cell lines, as we already showed for Hakin-1 (FIG. 4) and K1 (FIG. 24).

Effect of Selected Compounds on Invasion and Cell Viability in Tumour Culture Cells

Next, we studied the effect of the selected compounds K1, MKH1 and K8 compared to Hakin-1 on cell invasion. We tested the effect using the following concentrations 1 μM, 10 μM, 50 μM, and DMSO as control. A potent inhibitory effect using these inhibitors was detected on cell invasion (FIG. 30). Interestingly, Hakin-1 and K1 show a significantly decrease in the invasion assay between 1-10 μM, while 50% inhibition for MKH1 and K8 was achieved at approximately 1 μM highlighting their higher potency compared with Hakin 1 and K1. Moreover, cytotoxicity effect in HCT116 human colon cancer cells and in HEK293T non-cancerous cells was studied for these compounds. We used the concentrations tested in the previous assays. Interestingly, as observed in FIG. 31, no cytotoxic effect for K1, MKH1 was detected at the tested concentrations in human colon cancer cells neither in non-cancerous human cells. On the contrary, K8 shows an inhibitory response in cancer cells while no effect was detected in non-tumour cells. These results further underscore that K1, K8 and MKH1 increase E-cadherin expression, reduce cell proliferation and cell invasion without cytotoxic effect in non-tumour cells.

Effect of K1, MKH1 and K8 Inhibitors on Hakai-Induced Ubiquitination

Finally, we investigated the effect K1, MKH1 and K8 inhibitors on the ubiquitination induced by the E3 ubiquitin-ligase Hakai. As described in material and methods, HEK293T cells were transfected with Hakai and ubiquitin in presence of the selected inhibitors or DMSO as control. As sown in FIG. 32, K1 and MKH1 reduced ubiquitination at 20 μM and 100 μM while K8 reduce ubiquitination at 20 μM.

Collectively, our data demonstrate that the tested compounds show ant antitumor activity by inhibiting Hakai-mediated ubiquitination, increase E-cadherin expression at cell-cell contacts, reduces cell invasion, without cytotoxic effect in non-tumour epithelial cells.

TABLE 1
Summary of metabolites of Hakin-1 in hepatocyte
stability assay samples
Proposed Assignment Mouse
Hakin-1             ✓
MKH1                ✓

TABLE 2
Summary of Hakin-1 and the MKH1 metabolite areas and compound
percentage at 0 minutes (control) and 10 and 20 minutes in mouse
hepatocyte samples.
	Absolute area in sample	Area percentage in sample
	0 minute	10 minute	20 minute	0 minute	10 minute	20 minute
Peak ID	control	sample	sample	control	sample	sample
Hakin-1	43574	14090	2877	97.2%	26.2%	5.99%
MKH1	1235	39618	45169	2.76%	73.8%	94.0%

TABLE 3
Summary of metabolites observed at 20 minutes in mouse hepatocyte samples
						Retention
Peak ID	Mass	Biotransformation	Formula	m/z found	ppm error	time (min)
Hakin-1	385.0481	Parent	C16H11N5O5S	386.0556	−0.8	6.28
MKH1	387.0637	Reduction	C16H13N5O5S	388.0715	−0.1	6.09

Claims

1. A compound selected from any of the following list consisting of: a. A compound with the following chemical structure:

2. The compound for use according to claim 1, wherein the compound is the compound of list a).

3. The compound for use according to claim 1, wherein the compound is the compound of formula (II) of list b).

4. The compound for use according to claim 1, wherein the compound is the compound of formula (III) of list c).

5. The compound for use according to claim 1, wherein the compound is the compound of formula (IV) of list d).

6. The compound for use according to claim 3, wherein the compound is selected from the following list:

7. The compound for use according to claim 4, wherein the compound is selected from the following list:

8. The compound for use according to claim 5, wherein the compound is selected from the list consisting of:

9. The compound for use according to claim 2, wherein the cancer is a carcinoma.

10. The compound for use according to claim 2, wherein the cancer is a carcinoma selected from the list consisting of tumors arising from epithelial layers of the gastrointestinal track including month (oral cancer), esophagus, stomach, and small and large intestines (such as rectal or colon cancer), skin cancer, mammary gland (breast cancer), pancreas cancer, lung cancer, head and neck cancer, liver cancer, ovary cancer, cervix cancer, uterus cancer, gallbladder cancer, penile cancer, and urinary bladder cancer (such as renal, prostate or bladder cancer).

11. The compound for use according to any of claims 3 to 5, wherein the cancer is a carcinoma.

12. The compound for use according to any of claims 6 to 8, wherein the cancer is a carcinoma.

13. A compound as defined in claim 2 or a pharmaceutically acceptable salt thereof.

14. A pharmaceutical composition comprising the compound as defined in claim 2 or a pharmaceutically acceptable salt thereof.