Table 1 shows the comparison of the PT-262 and a variety of cytoskeleton inhibitors.
Appendix: the photographs of
The present invention will be more clear from the following description when viewed together with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the present invention.
The cell culture of PT-262, the experimental procedures, and the experiment results are described in conjunction with the accompanying drawings.
Cell Culture
The A549 cell line was derived from lung carcinoma of a 58-year-old male. The H1299 cell line has a homozygous deletion of the P53 gene that was derived from a non-small cell lung adenocarcinoma tumor. MCF-7 cell line was derived from breast adenocarcinoma of a 69-year-old Caucasian female. Hela cell line was derived from cervical carcinoma of a 31-year-old female. These cell lines are cultured in RPMI-1640 medium supplemented with 10% fetal bovine serum, 100 units/ml penicillin, 100 ug/ml streptomycin, and L-glutamine (0.03%, w/v), and cells were incubated at 37° C. and 5% CO2.
MTT Assay
Briefly, the cells were plated in 96-well plates at a density of 1×104 cells/well for 16-20 hours. Then the cells were treated with pt-262 for 24 hours in serum-free RPMI-1640 medium. After drug treatment, the cells were washed with phosphate-buffered saline (PBS), and were re-cultured in complete RPMI-1640 medium for 48 hours. Subsequently, the medium was replaced and the cells were incubated with 500 ug/ml MTT in complete RPMI-1640 medium for 4 hours. The surviving cells were dissolved in DMSO after removing the MTT medium, the molar absorptivity was measured at 565 nm using a ELISA reader.
Cell Growth Assay
The cells were plated at a density of 5×105 cells per p100 Petri dish for 16-20 hours. Then the cells were treated with PT-262 of different concentrations for 24 hours. After drug treatment, the cells were washed with PBS and re-treated with trypsin, the cells were suspended and were counted by a hemocytometer.
Cell Cycle Analysis
The cells were plated at a density of 1×106 cells per p60 dish for 16-20 hours. Then the cells were treated with PT-262 for 24 hours. After drug treatment, the cells were washed with PBS and re-treated with trypsin, the cells were suspended and collected in a 15 ml centrifuge tube. After centrifugation at 1500 rpm for 5 minutes, the cells were fixed with 70% ethanol and stored at −20° C. for at least 2 hours. After being re-centrifuged at 1500 rpm for 5 minutes, the cell pellets were incubated with 4 ug/ml propidium iodine solution containing 1% Triton X-100 and 100 ug/ml RNase A for 30 minutes. The cell cycle was then analyzed by flow cytometer, and the percentage of cell cycle was quantified by ModFit Lt software (Ver. 2.0).
Mitochondrial Membrane Potential
The cells were cultured in 60-mm Petri dish at a density of 5×105 cells. Then the cells were treated with PT-262 of different concentrations for 24 hours. After drug treatment, the cells were washed with PBS and were trypsinized, the cells were suspended and were counted by a hemocytometer. The cells were collected by centrifugation, and the pellets were resuspended in 70% ethanol and stored at −20° C. for at least 2 hours. After centrifugation, the pelts were incubated with 0.5 uM DiOC6 for 30 minutes. Then cell pellets were collected by centrifugation and resuspended in 0.5 ml ice-cold PBS. Finally, fluorescence intensities of DiOC6 were analyzed on a flow cytometer.
Western Blot
At the end of treatment, the cells were lysed in the cell extract buffer containing the protease inhibitators. Amounts of proteins in samples were subjected to electrophoresis using 10-12 sodium dodecyl sulfate-polyacrylamide gels. After electrophoretic transfer of proteins onto polyvinylidene difluoride (PVDF) membranes, the membranes were dipped in 5% degreased milk containing first antibody for 24 hours at 4° C. After being washed three times with TTBS buffer solution for 5-15 minutes at room temperature, the PVDF membranes are dipped in 5% degreased milk containing second antibody for 1-2 hours at room temperature. And then the membranes were re-washed three times with TTBS buffer solution for 5-15 minutes at room temperature. Finally, the protein bands were visualized using the enhanced chemiluminescence detection system.
Cytoskeleton Staining and Confocal Microscope
The cells were cultured on coverslips kept in a p60 Petri dish, and the coverslips were kept in a CO2 incubator for 16-20 hours. After being treated with or without PT-262, the cells were fixed in 4% parafomaldehyde solution for 60 minutes at 37° C. Then the coverslips were washed three times with PBS. The F-actin and β-tubulin were stained with 20 U/mi BODIPY FL phallacidin and anti-β-tubulin Cy3 for 30 minutes at 37° C., respectively. Finally, the nuclei were stained with 2.5 ug/ml Hoechst 33258 for 30 minutes. And the cells were added with 80% Glycerin and sealed with nail varnish. The samples were examined under a Leica confocal laser scanning mircroscope.
Statistical Analysis
All results were obtained at least from three separate experiments. Data were analyzed using Student's t test, and significant differences between values obtained from the population of cells treated with different conditions were compared. A p value of <0.05 was considered as statistically significant.
Results
The results of Cytotoxicity were analyzed by the MTT assay and were obtained from 3-14 experiments. * means p<0.05, ** means p<0.01, in comparison with treatments with and without PT-262. Treatment with 1-10 uM PT-262 for 24 hours, the cell survival ratio of the human A549 lung carcinoma cells (
For a better understanding of the present invention, please refer to
Reference is made to the following descriptions taken in conjunction with
To determine the mechanism of cell elongation induced by PT-262, the A549 cells were compared with a variety of cytoskeleton inhibitors including paclitaxel, colchichine, phalloidin, and cytochalasin B.
In comparison with various actions of cytoskeleton inhibitors (as shown in Table 1), we found that paclitaxel stabilized microtubules and induced microtublin polymerization to block the mitosis progression. Colchicines induced the mitotic arrest by inhibiting microtubule polymerization and destroying the mitotic spindle. Cytochalasins bound to the plus end of F-actin and prevented actin polymerization.
Paclitaxel, coichicines, and cytochalasin didn't induce the cell elongation. However, the phalloidin can bind and stabilize the side of F-actin, and inhibit the actin deploymerization. Like the phalloidin, PT-262 also increased the cell elongation by induction of the actin polymerization in lung carcinoma cells.
Therefore, the compound and the synthesis process of the present invention not only induced the elongation of the cancer cell, but also stabilized the side of F-actin, inhibited the actin deploymerization, affected the structure of the cytoskeleton and the extracellular matrix, prevented platelet aggregation, and produced an anti-coagulation effect. Other special functions of the present invention are described as follows:
1. PT-262 can increase the cell elongation by stabilization of the F-actin and induction of the actin polymerization in carcinoma cells, meanwhile, inhibit the small GTPase proteins, including Ras, Rac, Rho and cdc42, and their downstream proteins.
2. As an inhibitor of the cdc2 activating kinase and the cdc 25, PT-262 can also inhibit the corresponding proteins downstream of the cdc2 and cdc 25.
3. PT-262 inhibited the Ras-ERK survival signal pathway, including all the corresponding upstream and downstream proteins, and prevented the survival, proliferation, and transformation of the cancer cells.
4. Pt-262 increased the cell elongation, decreased the mitochondrial membrane potential, and induced the caspase-3 activation and its upstream and downstream proteins.
5. PT-262 stabilized the side of F-actin, inhibited the actin deploymerization of the cancer cells, affected the structure of the cytoskeleton and the extracellular matrix, prevented platelet aggregation, and produced an anti-coagulation effect.
6. PT-262 can stabilize the side of F-actin, inhibit the actin deploymerization of the other cells, promote the neurotransmission and induce angiogenesis.
In addition, other derivatives of 7-chloro-6-piperidin-1-yl-quinoline-5,8-dione are also within the scope of the present invention and possess the aforementioned functions and effects.
While we have shown and described various embodiments in accordance with the present invention, it is clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.
Number | Date | Country | Kind |
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095125884 | Jul 2006 | TW | national |