Patent Application
20200157543
The present invention relates to a biomolecule imaging method using aptamer, and more particularly, to a method for obtaining images by using aptamer labeled with isotope and binding the same to a human epidermal growth factor receptor 2 (HER2) expressing cell line.
The etymology of aptamer was derived from the Latin meaning of “aptus (exactly right)” and the Greek meaning “meros (partial).” The aptamer is a single-stranded nucleic acid having a DNA sequence consisting of about 20 to 90 bases. Usually, aptamer highly specific to a target molecule and having a high affinity thereto is screened through an artificial evolution method such as in vitro SELEX (Systematic Evolution of Ligands by Exponential Enrichment) as an aptamer excavation technology. Therefore, the aptamer is regarded as a very suitable reagent to determine or find a degree of expression of specific molecules to be targeted by the aptamer. In several aspects such as reduced production costs, easy synthesis, low toxicity, no occurrence of immune response, and no production of the aptamer in an animal system unlike an antibody, etc., the aptamer has advantages as compared to the antibody. The aptamer is a reagent relatively newly developed in diagnosis fields. A number of aptamers for a wide variety of targets including thrombin, nucleolin, PSMA, TNC and virus origin proteins have been developed. In therapeutic fields, VEFG target aptamer was developed and approved as elderly macular degeneration therapeutic agents by the FDA in 2004. Recently, so many types of aptamers are under development in pre-clinical and clinical phases and a number of experiments relevant to diagnosis and treatment are in the process.
HER2 is a cancer gene very well known in the art, which is increased or over-expressed in about 15 to 30% of breast cancer. Further, this is a factor associated with high recurrence and poor prognosis of different cancers. There are two signaling systems activated by HER2, including a MAPK route promoting cell proliferation and a PI3K-AKT route increasing survival of cancer cells. Therefore, the above factor is a highly preferred target for application in treatment of cancer. In this regard, transtuzumab and pertuzummab for targeting HER2 currently exist as therapeutic monoclonal antibodies well known and available in the art, and have been found to be effective in clinical applications. Before then, several HER2 targeting DNA/RNA aptamers were disclosed through traditional SELEX methods and cell-based SELEX. Moreover, examples of pharmaceutically utilizing cancer inhibitory properties of the HER2 aptamers have been recently reported.
Meanwhile, molecule images may be a non-invasive method that enables real-time visualization of biochemical events in a cellular molecular level in regard to living cells or tissues or objects without damage. The aptamer modified into a magnetic nano-material or fluorescent material may be provided as a preferred substance for targeted fluorescence imaging or magnetic resonance imaging (MRI). Some in vivo MRI studies demonstrated efficiently targeted cancer in mice having cancer. However, due to metabolic changes occurring before anatomic changes, PET is distinctly more advantageous in a diagnostic aspect than anatomical techniques such as computed tomography (CT) and MRI. In clinical applications, PET is broadly used in basic research and preclinical fields. For instance, the PET may be used to verify or validate analysis of new radio-therapeutics, therapeutic efficacy of novel therapeutic agents and in vivo distribution of drugs. Merits of PET may include probe depth, superior sensitivity, quantitative data and convertibleness (i.e., phase progress) from pre-clinical trials to clinical trials. That is, the PET is a representative molecule imaging device that can detect biochemical changes in a target level of living biomolecules and is highly sensitive, thereby being used in a wide range of applications including basic science and pre-clinical area. Cancer targeting using aptamer is a biomolecule imaging technique proposed in recent years, and for example, many researchers including Hicke et. al. have adopted aptamer in molecule imaging. They have bound 99mTC to an aptamer called TTA1 bound to tenascin-C as an extracellular protein through a covalent bond, and then imaged cancer using a gamma-camera in vivo. Since then, PET imaging has also been implemented by other researcher teams.
However, implementation of PET imaging using HER2-specific ERBB2 aptamer has not been disclosed.
Aptamer is one of nucleic acids and a material with high specificity and affinity to a target molecule. It is an object of the present invention to provide molecular images in vivo using radioactive isotope or fluorescent dye-labeled aptamer.
According to the present invention, HER2 aptamer labeled with a radioactive isotope or fluorescent dye is used for in vivo imaging.
In flow cytometric analysis, ERBB2 aptamer is almost not bound to MDA-MB231 cell line without expression of HER2, but may have very high affinity to BT474 as a HER2 expressing cell line. Similarly, it is observed from images obtained by a confocal microscope that the aptamer is bound to HER2 expressed breast cancer cell line, while showing only minimum binding to HER2 non-expressing cells. Molecular images of positron emission tomography for a mouse transplanted in vivo with BT474 cancer cell line have demonstrated a significant increase in intake of 18F-labeled HER2-specific ERBB2 aptamer. ERBB2 aptamer may be preferentially bound to HER2 expressed breast cancer cell line both in vitro and in vivo, and the reason is that HER2 structure is possibly recognized on the surface of the cells.
ERBB2 aptamer labeled with a radioactive isotope such as 18F or a fluorescent dye may recognize HER2 expression in human breast cancer cells and enable adequate visualization. These results suggest a target treatment application using such an isotope or fluorescent dye-labeled ERBB2 aptamer to HER2-positive breast cancer cells or a potential application method how to treat the same.
In this regard, Table 3 shows a hybridization structure of R-[ERBB2 aptamer]-ODN-X (R═H, cholesterol or PEG, and X═H or idT) and cODN-L-F18 (L=linker), which is represented by R-[ERBB2 aptamer]-X-hy(bp)-L-F18.
ERBB2 aptamer specifically bound to HER2 receptor in relevant to breast cancers, which is used in the present invention, has a DNA sequence of 5′-TCAGCCGCCAGCCAGTTC-[core sequence]-GACCAGAGCACCACAGAG-3′ wherein the number ‘6’ in the core sequence or ‘n’ in the attached DNA sequence listing represents NaptyldU.
6=NapdU [5-(N-Naphthylcarboxyamide)-[0070] 2′-deoxyuridine]. In the present invention, HER2 aptamer labeled with a radioactive isotope (‘radioisotope’), for example, 18F, 32P, 123I, 89Zr, 67Ga, 201Tl and 111In-111, or a fluorescent dye, for example, a cyanine fluorescent dye such as Cy3, Cy5, Cy7, etc. was utilized for in vivo imaging. In embodiments of the present invention, evaluation of target specificity for in vivo molecule imaging and potential clinical application have been performed using ERBB2 aptamer labeled with the radioisotope or fluorescent dye.
ERBB2 aptamer for a human epidermal growth factor receptor 2 (HER2) was labeled with 18F-fluoride isotope. In order to confirm that the aptamer entered HER2 expressed cancer cell line, the aptamer was compared with a control aptamer by flow cytometry and confocal microscope. The 18F-labeled HER2-specific ERBB2 aptamer was subjected to positron tomography thus to obtain biomolecular images of the mice transplanted with BT474 or KPL4 cells over time.
Hereinafter, the present invention will be described in detail.
Cell Culture
HER2 expressed human breast cancer cell lines, e.g., BT474, KPL4, N89 and SK-BR-3 were used for in vitro and in vivo experiments. Further, a human breast cancer cell line MDA-MB231 was used as a control group. All cell lines were purchased from ATCC and incubated and maintained in MEM medium containing 10% FBS.
Cell Lysis, Western Blot
In order to extract intracellular protein, a cell lysate including a protease inhibitor was incubated on ice for 30 minutes. The resulting cell lysate was purified by centrifugation at 4° C. for 20 minutes. For protein quantification, the cell lysate was quantified by Bradford method, followed by separation of 30 μg protein extract from the respective samples through electrophoresis using 10% SDS-PAGE. Then, the resulting product was transferred to a nitrocellulose membrane and subjected to photosensitization on x-ray film with ECL, using HER2 antibody and the control group, that is, a beta-action antibody as a probe.
ERBB2 Aptamer Synthesis
DNA sequences of HER2-(+) targeting ERBB2 aptamers are shown in Table 2 below.
The RBB2 aptamers, in particular, AP001-24 has a binding affinity (Kd) of 3.1 nM to a target and AP001-25 has a binding affinity of 0.9 nM.
Herein, 6 denotes NapdU [5-(N-naphthylcarboxamide)-2′-deoxyuridine] represented by the following formula, A=2′-deoxyadenosine, G=2′-deoxyguanosine and C=2′-deoxycytidine.
For aptamer hybridization, synthesis including a fully matching sequence, that is, ODN (5′-CAGCCACACCACCAG-3′) (SEQ ID NO: 36) at 3′ in each of the ERBB2 aptamers {[AP001-24] and [AP001-25]} was performed.
[AP001-24]-ODN Synthesis
5′-[6CC 6GG CA6 G66 CGA 6GG AGG CC6 66G A66 ACA GCC CAG A]-CAG CCA CAC CAC CAG-3′ {[AP001-24]-ODN} was synthesized as follows.
Aptamer synthesis was performed by a solid phase synthesis process through phosphoramidite coupling reaction, and after the synthesis, the product was reacted in a t-butylamine:methanol:water (1:1:2 v/v/v) solution at 70° C. for 5 hours, thus to obtain a complete aptamer through cleavage and deprotection processes, followed by drying the same. The synthesized aptamer was isolated by HPLC [C18 column (Waters, Xbridge OST C18 10×50 mm, 260 nm] and then was subjected to measurement of a molecular weight by means of ESI MS mass spectrometer (Qtrap2000, ABI).
11th aptamer in Table 1 (SEQ ID NO: 11) corresponds to AP001-24.
[AP001-25]-ODN Synthesis:
5′-[A6G 66A GAG 666 GCC 6GA G6G CC6 CGC AAG GGC G6A ACA A]-CAG CCA CAC CAC CAG-3′ {[AP001-25]-ODN} was synthesized by the same synthesis procedures as described in the above section for {[AP001-24]-ODN} synthesis.
12th aptamer in Table 1 (SEQ ID NO: 7) corresponds to AP001-25.
In the same manner, each of aptamers, that is, CAG-3′ {each of aptamers (SEQ ID NOs: 1-35) in Table 1-ODN} was synthesized by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
[AP001-24]-ODN-idT Synthesis:
5′-[6CC 6GG CA6 G66 CGA 6GG AGG CC6 66G A66 ACA GCC CAG A]-CAG CCA CAC CAC CAG-idT-3′ {[AP001-24]-ODN-idT} was synthesized using idT (invert dT) CPG (Glen, 20-0302-10) by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
[AP001-25]-ODN-idT Synthesis:
5′-[A6G 66A GAG 666 GCC 6GA G6G CC6 CGC AAG GGC G6A ACA A]-CAG CCA CAC CAC CAG-idT-3′ {[AP001-25]-ODN-idT} was synthesized using idT CPG (Glen, 20-0302-10) by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
Cholesteryl-[AP001-24]-ODN Synthesis:
5′-cholesteryl-[6CC 6GG CA6 G66 CGA 6GG AGG CC6 66G A66 ACA GCC CAG A]-CAG CCA CAC CAC CAG-3′ {cholesteryl-[AP001-24]-ODN} was synthesized using cholesterol-PA (Glen, 10-1976-90) by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
Cholesteryl-[AP001-25]-ODN Synthesis:
5′-cholesteryl-[A6G 66A GAG 666 GCC 6GA G6G CC6 CGC AAG GGC G6A ACA A]-CAG CCA CAC CAC CAG-3′ {cholesteryl-[AP001-25]-ODN} was synthesized using cholesterol-PA (Glen, 10-1976-90) by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
Cholesteryl-[AP001-24]-ODN-idT Synthesis:
5′-cholesteryl-[6CC 6GG CA6 G66 CGA 6GG AGG CC6 66G A66 ACA GCC CAG A]-CAG CCA CAC CAC CAG-idT-3′ {cholesteryl-[AP001-24]-ODN-idT} was synthesized using idT CPG (Glen, 20-0302-10) and cholesterol-PA (Glen, 10-1976-90) by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
Cholesteryl-[AP001-25]-ODN-idT Synthesis:
5′-cholesteryl [A6G 66A GAG 666 GCC 6GA G6G CC6 CGC AAG GGC G6A ACA A]-CAG CCA CAC CAC CAG-idT-3′ {cholesteryl-[AP001-25]-ODN-idT} was synthesized using idT CPG (Glen, 20-0302-10) and cholesterol-PA (Glen, 10-1976-90) by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
PEGylated-[AP001-24]-ODN Synthesis:
5′-PEGylated-[6CC 6GG CA6 G66 CGA 6GG AGG CC6 66G A66 ACA GCC CAG A]-CAG CCA CAC CAC CAG′ {PEGylated-[AP001-24]-ODN} was synthesized using polyethyleneglycol 2000 CED PA (ChemGenes, CLP-2119) by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
PEGylated-[AP001-25]-ODN Synthesis:
5′-PEGylated-[A6G 66A GAG 666 GCC 6GA G6G CC6 CGC AAG GGC G6A ACA A]-CAG CCA CAC CAC CAG-3′ {PEGylated-[AP001-25]-ODN} was synthesized using polyethyleneglycol 2000 CED PA (ChemGenes, CLP-2119) by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
PEGylated-[AP001-24]-ODN-idT Synthesis:
5′-PEGylated-[6CC 6GG CA6 G66 CGA 6GG AGG CC6 66G A66 ACA GCC CAG A]-CAG CCA CAC CAC CAG-idT-3′ {PEGylated-[AP001-24]-ODN-idT} was synthesized using idT CPG (Glen, 20-0302-10) and polyethyleneglycol 2000 CED PA (ChemGenes, CLP-2119) by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
PEGylated-[AP001-25]-ODN-idT Synthesis:
5′-PEGylated-[A6G 66A GAG 666 GCC 6GA G6G CC6 CGC AAG GGC G6A ACA A]-CAG CCA CAC CAC CAG-3′ {PEGylated-[AP001-25]-ODN-idT} was synthesized using idT CPG (Glen, 20-0302-10) and polyethyleneglycol 2000 CED PA (ChemGenes, CLP-2119) by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
Cy5 Conjugated cODN (Complementary Oligonucleotide)[cODN-Cy5] Synthesis:
The following figure represents structures of cODN-Cy5 and cODN-L-F18 (L=linker) and synthesis thereof.
5′-Cy5-[CTGGTGGTGTGGCTG]-3′ (SEQ ID NO: 37) [cODN-Cy5] was synthesized using Cy5-PA (Glen, 10-5915-10) by the same procedures as described in the above section for {[AP001-24]-ODN} synthesis.
Formation of Cy5-Labeled ERBB2 Aptamer
Table 3 below shows a hybridization structure of R-[ERBB2 aptamer]-ODN-X (R═H, cholesterol or PEG, and X═H or idT) and cODN-Cy5, which is represented by [ERBB2 aptamer]-X-hy(bp)-Cy5.
The Cy5-labeled ERBB2 aptamer, that is, {R-[ERBB2 aptamer]-X-hy(bp)-Cy5} was prepared in the following manner.
First, cODN-Cy5 and [ERBB2 aptamer]-ODN in equal moles were put in an annealing buffer (PBS). Herein, a concentration of MgCl2 was controlled to reach a final concentration of 10 mM. This reaction product was left at 95° C. for 5 minutes, and then slowly cooled at room temperature. Hybridization efficiency of cODN-Cy5 and [ERBB2 aptamer]-ODN was assessed by electrophoresis (Typhoon FLA 7000 3% agarose gel analysis) and HPLC (XBridge OST analytical column (2.5 μm, 4.6×50 mm, Waters, 254 nm, 0.1M TEAA/acetonitrile).
Complementary base pairing between a synthetic oligonucleotide labeled with a fluorescent dye, that is, Cy5 (cODN-Cy5), and [ERBB2 aptamer]-ODN, was assessed. After mixing cholesteryl-[AP001-24]-ODN-idT or cholesteryl-[AP001-24]-ODN and cODN-Cy5 in 1:1 ratio, a temperature was maintained so that these components are bound together at 55, 60 and 65° C. In order to confirm the binding, electrophoresis was conducted in 3% agarose gel, followed by fluorescent imaging Cy5 through FLA 5000. Then, the entire aptamer was stained with EtBr and was subjected to UV imaging. The results are shown in
Formation of F18 Radioisotope-Labeled cODN (Complementary Oligonucleotide) [cODN-L-F18]
Synthesis of 18F-labeled cODN was performed on the basis of the process already reported in the art (see reference 24). After generating no-carrier-added 18F-fluoride ions in a synthesis device (Tracerlab FXFN, GE Healthcare, Milwaukee, Wis., USA) and reacting the same with mesylate (at 100° C. for 10 minutes), 18F-fluoro-PEG-azide (18F-FPA) was purified by using HPLC. After adding 1M N,N-disopropyl ethylamine in acetonitrile (10 mL) and 100 mM copper iodide (I) in acetonitrile (20 mL) to 5′-hexynyl complementary oligonucleotide (5′-hex-cODN; 200 mg), 18F-FPA (750e 1100 MBq) was further added thereto, followed by click chemistry reaction (at 70° C. for 20 minutes). The synthesized 18F-labeled cODN (cODN-L-F18) was purified by using HPLC H (Xbridge OST C18 10×50 mm, an eluent of acetonitrile/0.1M TEAA in 5:95 to 95:5 over 20 minutes, flow rate: 5 mL/min, and UV (254 nm)).
Formation of F18 Radioisotope-Labeled ERBB2 Aptamer {R-[ERBB2 Aptamer]-X-hy(bp)-L-F18]
Table 4 below shows a hybridization structure of R-[ERBB2 aptamer]-ODN-X (R═H, cholesterol or PEG, and X═OH or idT) and cODN-L-F18 (L=lnker), which is represented by [ERBB2 aptamer]-X-hy(bp)-L-F18.
F18 radioisotope-labeled ERBB2 aptamer, {R-[ERBB2 aptamer]-X-hy(bp)-L-F18} was prepared in the following manner.
First, cODN-L-F18 and [ERBB2 aptamer]-ODN in equal moles were put in an annealing buffer (PBS). Herein, a concentration of MgCl2 was controlled to reach a final concentration of 10 mM. This reaction product was left at 95° C. for 5 minutes, and then slowly cooled at room temperature. Hybridization efficiency of cODN-L-F18 and [ERBB2 aptamer]-ODN was assessed by using HPLC (XBridge OST analytical column (2.5 μm, 4.6×50 mm, Waters, 254 nm, 0.1M TEAA/acetonitrile). These products were combined at a hybridization rate of 98% or more.
Confocal Microscope
BT474, KPL4, N87, SK-BR-3 and MDA-MB231 cell lines were dispensed on a coverslip and incubated overnight. When about 80% of the cell lines were grown, the grown cells were carefully washed and incubated by treatment using fluorescence-labeled ERBB2 aptamer {R-[ERBB2 aptamer]-hy(bp)-Cy5} at a concentration of 250 mM. After culture, the product was carefully washed, followed by loading a culture medium containing DAPI on a slide. Then, florescence thereof was observed by an LSM 700 confocal microscope. Microscope setting was performed as follows: a 488 laser was used for FITC observation; excitation and emission were observed using BP490-555; a 639 laser was used for Texas red; and emission was observed using an LP640 filter.
In the same manner as the previous experiments, ERBB2 over-expressing breast cancer cell lines, e.g., KPL4, N87 and SK-BR-3 were dispensed on a coverslip and incubated overnight. When about 80% of the cell lines were grown, the grown cells were carefully washed and incubated by treatment using a sample prepared of Cy5 fluorescence-labeled ODN bound to ERBB2 aptamer using complementary base pairing. After culture, the product was carefully washed, followed by loading a culture medium containing DAPI on a slide. Then, florescence was observed by an LSM 700 confocal microscope.
The observed results are shown in
Flow Cytometry
Specificity of ERBB2 aptamer was verified by a fluorescence activated cell separation method using a flow cytometry system (BD Biosciences). Appropriate numbers of BT474, KPL4, N87, SK-BR-3 or MDA-MB231 cancer cell lines were sub-cultured on a Petri-dish to grow the same to about 80%. The grown cells were treated with trypsin and washed with PBS, followed by binding fluorescence-labeled ODN to ERBB2 aptamer through a complementary base generated according to a temperature. The cells were treated with the binding-completed sample. Both of the ERBB2 aptamer {R-[ERBB2 aptamer]-hy(bp)-Cy5} and the control group, that is, 1% FES containing antibody were treated at 4° C. for 30 minutes, respectively. The completely treated sample was washed, followed by measurement and analysis of the bound ERBB2 aptamer by a fluorescence activated cell separation method.
Results of the above measurement and analysis are shown in
In Vivo Experiments
17ββ-estradiol pellets were subcutaneously implanted into a side region of the neck of a 4 week-old Balb/c nude mouse so that estrogen is released in a sufficient amount to potentially induce a cancer. A few days later, BT474 or KPL4 human breast cancer cell line was subcutaneously implanted in 7×106 cells per mouse. After allowing the cancer to develop for 3 weeks, cancer growth was measured using a caliper.
Into the right shoulder of Balb/C nude mouse, KPL4 cells as the human breast cancer cell line were subcutaneously implanted in 1×105 cells per mouse. Thereafter, occurrence of cancer was induced.
PET Imaging of Fn Radioisotope-Labeled ERBB2 Aptamer
F 18 radioisotope-labeled ERBB2 aptamer was injected to a mouse, and after 60 minutes, static images were obtained by Inveron microPET scanner (Siemens, Knoxville, Tenn., USA) for 10 minutes. For F18 radioisotope-labeled ERBB2 aptamer injection, the mouse was breathing anesthetized with 2% Isoflurane, followed by 7.4 MBq of F18 radioisotope-labeled ERBB2 aptamer injection into a tail vein. The obtained listmode data is converted into synogram and re-configured by 3D Ordered Subset Expectation Maximization (OSEM) algorithm, followed by assessment using ASIpro (Concord Microsystems Inc., Knoxville, Tenn.).
After intravenous injection of F18 radioisotope-labeled ERBB2 aptamer to a mouse having tumor grown by injection of human breast tumor cells, PET was executed using inveon PET of Siemens (Knoxville, Tenn.). The injected amount was 13.7±1.1 MBq (370±30 uCi), and dynamic PET study was implemented for 30 minutes according to ten 1-minute image and four 5-minute image protocols. These two stationary studies were conducted for 10, 60, 90 and 120 minutes, respectively, after the injection. Partial quantification of PET signals was executed by AMIDE software. Images were practically gained by false-color-scale in proportional to the tissue concentration (% ID/g) of a positron labeling probe. Red represents the highest concentration, while yellow, green and blue correspond to gradually lower concentrations.
PET images are shown in
Result
Verification of HER2 Expression and Affinity of Aptamer to Target Tumor Cell
Western blot and flow cytometry were performed to investigate HER2 expression in a breast cancer cell line, BT474. Through western blot analysis, over-expression in BT474 as well as SKBR3 cell line known to over-express HER2 due to gene amplification was confirmed. Further, it was found that no signal is detected at the corresponding site in a negative control cell line, MDA-MB231 (
As shown in
Confocal Microscope Analysis
Binding of ERBB2 aptamer to cells was further assessed by a confocal microscope (
In Vivo PET Imaging, In Vivo Distribution, Immuno-Histochemistry
In vivo bio-molecular images of mice having BT474 or KPL4 cancer were given over time according to animal micro-PET. Referring to
In vivo distribution was verified in the mice having cancer, 1 hour after injection of 18F-labeled ERBB2 aptamer. After sacrificing the animal, radiation levels in separate tissues including the cancer were measured by a gamma counter, and then expressed in % ID/g (
The intake of 18F-labeled ERBB2 aptamer in the cancer was 0.62±0.04 per hour. Study on in vivo distribution demonstrated that the kidney and the intestine are two major discharge routes of 18F-labeled ERBB2 aptamer.
According to the present invention, HER2 targeting ERBB2 aptamer was successfully PET-imaged in vivo. The present invention is the first case to execute HER2 target PET imaging using ERBB2-specific aptamer. In mice with BT474 cancer, PET images demonstrated that ERBB2 aptamer may recognize HER2 in vivo and relatively distinctively show the cancer. Based on these results, the radiolabeled ERBB2 aptamer may be applied to targeted treatment of HER2-positive breast cancer cell line or potentially applied to determination of appropriate therapeutic methods for the same.
As identified in the above embodiments, when R-[ERBB2 aptamer]-ODN-X/cODN-L-F18 (represented by R-[ERBB2 aptamer]-X-hy(bp)-L-F18 in the above description) is prepared by combining R-[ERBB2 aptamer]-ODN-X with cODN-L-F18, the aptamer chemically modified (i.e., protected) at 5′ terminal or 3′ terminal position, or both of these terminal positions, for example, from R═H (No protecting) and X═H (No protecting) to R═cholesterol or PEG (polyethyleneglycol) and X═idT (inverted deoxythymidine), LNA (locked nucleic acid), 2′-methoxy nucleotide, 2′-amino nucleotide, 2′F-nucleotide, etc., may assure better images.
Since the modification due to the above compounds may improve effects of increasing t1/2 (half-life) blood clearance, that is, increase in vivo half-life in blood, ERBB2 aptamer having a radioisotope bound thereto is increasingly bound to a tumor thus to improve imaging efficiency [as compared to t1/2=10 minutes when R═H and X═H, t1/2 increases to 1 hour if R and X are protected and modified, thereby demonstrating better images].
Discovery and development of therapeutic aptamers. Annual review of pharmacology and toxicology. 2010; 50: 237-57.
A sequence listing electronically submitted with the present application on Oct. 25, 2019 (filing date) as an ASCII text file named 20191025_Q16819LC39_TU_SEQ, created on Oct. 24, 2019 (saved date) and having a size of 13312 bytes, is incorporated herein by reference in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2017-0053456 | Apr 2017 | KR | national |
| 10-2018-0046550 | Apr 2018 | KR | national |
This application claims benefit under 35 U.S.C. 119(e), 120, 121, or 365(c), and is a National Stage entry from International Application No. PCT/KR2018/004770, filed on Apr. 25, 2018, which claims priority to the benefit of Korean Patent Application No. 10-2017-0053456 filed on Apr. 26, 2017 and 10-2018-0046550 filed on Apr. 23, 2018 in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2018/004770 | 4/25/2018 | WO | 00 |
