CP2C-TARGETING PEPTIDE-BASED ANTICANCER AGENT
20220160888 · 2022-05-26
Assignee
- INDUSTRY-UNIVERSITY COOPERATION FOUNDATION HANYANG UNIVERSITY (Seoul, KR)
- Konkuk University Glocal Industry-Academic Collaboration Foundation (Chungju-si, Chungcheongbuk-do, KR)
- Korea National University of Education Industry-Academy Cooperation Foundation (Cheongwon-gun, Chungcheongbuk-do, KR)
Inventors
- Chul Geun KIM (Seoul, KR)
- Min Young Kim (Seoul, KR)
- Chan Gil KIM (Chungju-si, KR)
- Seung Han SON (Incheon, KR)
- Ji Sook KIM (Uijeongbu-si, KR)
- Sung Woo CHOI (Gimpo-si, KR)
- Seol Eui LEE (Seoul, KR)
- Min Sung CHUNG (Seoul, KR)
- Dong Sun PARK (Cheongju-si, KR)
- Sang Won Lee (Seoul, KR)
- Jae Min JEONG (Seoul, KR)
- Dong Ho CHOI (Seoul, KR)
- Ki Seok JANG (Seoul, KR)
Cpc classification
A61K47/65
HUMAN NECESSITIES
C07K2319/10
CHEMISTRY; METALLURGY
A61K47/64
HUMAN NECESSITIES
C07K2319/035
CHEMISTRY; METALLURGY
A61K47/542
HUMAN NECESSITIES
A61P35/00
HUMAN NECESSITIES
International classification
A61K47/64
HUMAN NECESSITIES
A61K47/65
HUMAN NECESSITIES
Abstract
The presented invention relates to a CP2c-targeting peptide-based anticancer agent. A CP2c-targeting peptide according to the presented invention binds to transcription factor CP2c to inhibit the formation of transcription factor CP2c complexes (CP2c homotetramer and CP2c/CP2b/PIAS1 heterohexamer), thereby inducing cancer cell-specific cell death. A fatty acid is bound to the peptide to ensure stability enabling long-term sustenance in vivo.
Claims
1. A CP2c-targeting peptide-fatty acid conjugate, comprising: a transcription factor CP2c-targeting peptide consisting of 4 to 20 amino acids; a linker peptide bonded to an N- or C-terminal of the CP2c-targeting peptide; a cell-penetrating peptide (CPP) bonded to the C-terminal of the CP2c-targeting peptide, or a C-terminal of the linker peptide bonded to the C-terminal of the CP2c-targeting peptide; and a fatty acid conjugated with the linker peptide, wherein the transcription factor CP2c-targeting peptide comprises an amino acid sequence represented by SEQ ID NO: 1.
2. The CP2c-targeting peptide-fatty acid conjugate according to claim 1, wherein the transcription factor CP2c-targeting peptide comprises an amino acid sequence represented by SEQ ID NO: 2.
3. The CP2c-targeting peptide-fatty acid conjugate according to claim 1, wherein an N- and/or C-terminal of the peptide of the CP2c-targeting peptide-fatty acid conjugate is modified to increase stability.
4. The CP2c-targeting peptide-fatty acid conjugate according to claim 3, wherein an N-terminal of the peptide of the CP2c-targeting peptide-fatty acid conjugate is modified with an acetyl group, and a C-terminal of the peptide is modified with an amide group.
5. The CP2c-targeting peptide-fatty acid conjugate according to claim 1, wherein the linker peptide consists of an amino acid sequence represented by G.sub.nKG.sub.m, wherein n and m are each independently an integer of 0 to 6.
6. The CP2c-targeting peptide-fatty acid conjugate according to claim 1, wherein the fatty acid is one of C.sub.12 to C.sub.20 fatty acid.
7. The CP2c-targeting peptide-fatty acid conjugate according to claim 5, wherein the fatty acid is a modified fatty acid peptide-bonded to glutamic acid (Glu, E), or a modified fatty acid peptide-bonded to glycine (Gly, G) of an amino acid sequence represented by EGLFG, wherein the glutamic acid or glutamic acid of the amino acid sequence represented by EGLFG, bonded to the fatty acid, is bonded to lysine (Lys, K) of an amino acid sequence represented by G.sub.nKG.sub.m.
8. The CP2c-targeting peptide-fatty acid conjugate according to claim 7, wherein the fatty acid is a C.sub.16 palmitoyl acid, and a functional group of lysine (Lys, K) of the amino acid sequence represented by G.sub.nKG.sub.m is bonded to a gamma carbon carboxyl group of the glutamic acid.
9. A pharmaceutical composition for preventing or treating cancer, comprising the CP2c-targeting peptide-fatty acid conjugate according to claim 1 as an active ingredient.
10. A health functional food composition for preventing or alleviating cancer, comprising the CP2c-targeting peptide-fatty acid conjugate according to claim 1 as an active ingredient.
Description
BRIEF DESCRIPTION OF DRAWINGS
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BEST MODE
[0071] Hereinafter, the presented invention will be described in more detail with reference to the following examples. It should be understood that the examples are included merely to concretely explain the spirit of the invention, and do not serve as any sort of limits of the presented invention.
[Preparation Example 1] Preparation of CP2c-Targeting Peptide Conjugated with Cell-Penetrating Peptide
[0072] The transcription factor CP2c is known to be overexpressed in various cancers. According to a study by a US research team, it was reported that inhibition of CP2c expression in liver cancer cell lines inhibited cell growth, whereas overexpression of CP2c caused cancer malignancy and metastasis [Grant et al., Antiproliferative small-molecule inhibitors of transcription factor LSF reveal oncogene addiction to LSF in hepatocellular carcinoma, Proc. Natl. Acad. Sci. 2012; 109 (12): 4503-4508].
[0073] The present inventors identified peptides binding to transcription factor CP2c (also known as Tfcp2, LSF, LBP1, UBP1, etc.) by a phage display method [Kang et al., Identification and characterization of four novel peptide motifs that recognize distinct regions of the transcription factor CP2, FEBS Journal 2005; 272:1265-1277], selected one type of peptide (CP2c-targeting peptide, SEQ ID NO: 2) that was derived from one peptide interfering with DNA binding of CP2c among the identified peptides, and synthesized an ACP52C lead material by binding the internalizing RGD (iRGD) peptide consisting of 9 amino acids (9 aa) ‘CRGDKGPDC’ (Cys-Arg-Gly-Asp-Lys-Gly-Pro-Asp-Cys, SEQ ID NO: 3) as a cell-penetrating peptide (CPP) to the CP2c-targeting peptide so as to improve cell permeability (
[Example 1] Confirmation of Anti-Cancer Effect of ACP52C
[0074] The selected peptide binds to CP2c and inhibits the formation of a transcription factor complex including CP2c (CP2c homotetramer and CP2c/CP2b/PIAS1 heterohexamer), thereby indirectly interfering with DNA binding of CP2c. As a result of analyzing the anticancer effect in various carcinomas targeting the synthesized ACP52C, it was confirmed that it exhibits cancer cell-specific growth inhibition and cell death efficacy (
[0075] The growth inhibitory and cell death-inducing efficacy of ACP52C was confirmed by FACS analysis by treating cells with ACP52C after synchronizing the cell cycle to the G1/S phase through a double thymidine block method. As a result, it was confirmed that a polyploid was formed while with cell cycle arrest at the G2/M phase. On the other hand, it was confirmed that, when ACP52C was applied to the cell line synchronized to the G2/M phase with thymidine/nocodazole treatment, the cell cycle was arrested at the subG1 phase and cell death was induced (
[0076] It was confirmed that the ACP52C-induced G2/M phase arrest was caused by the increased expression of CHK1/2 protein and the decreased expression of CDCl.sub.25c, CDK1, and cyclin B proteins, whereas the cell death induction was caused by the increased expression of pro-apoptotic proteins along with the decreased expression of anti-apoptotic marker proteins, and the apoptosis via activation of caspases (
[0077] The subcellular movement, localization, and stability of ACP52C in the cells treated with the Cy5-labeled peptide (Cy5-ACP52C) for 30 minutes were analyzed by confocal microscopy over time. The most peptide passed through the cytoplasm, located in the nucleus from 4 hours, moved back to the cytoplasm at 8 hours, and degraded in the cytoplasm at 16 hours. It was confirmed that the Cy5-ACP52C peptide was co-located with CP2c in the nucleus from 1 hour after treatment, and CP2c also tends to be distributed in the cytoplasm at 8 hours after treatment along with Cy5-ACP52C (
[0078] The ACP52C half-life in the solution containing serum was analyzed by HPLC (model: UHPLC DIONEX Ultimate 3000; Flow=1.000 ml/min) after incubation of ACP52C in the solution containing 10% serum for various times and then removing serum proteins with Centricon (Mw10,000) before HPLC analysis. As a result of the experiment, ACP52C was not degraded at all until 24 hours. Meanwhile, after injecting ACP52C into the mouse via tail vein, blood samples were extracted over time and the degree of ACP52C degradation in the blood samples was analyzed by HPLC. As a result, EC50 (time retaining 50% of the intact ACP52C) was about 2 hours. Additionally, when the remained intensity of fluorescence in the mouse body was measured by live imaging process over time in the Cy5-labeled peptide (Cy5-ACP52C)-injected mouse via tail vein, ACP52C was observed in cancer tissues even 5 days after injection although the total fluorescence intensity in the mouse body was halved at 7.95 hours after treatment (
[Preparation Example 2] Synthesis of CP2c-Targeting Peptide-Fatty Acid Conjugates
[0079] Our data suggest that ACP52C might be unstable in vivo although ACP52C showed a good anticancer activity. As an effort to improve in vivo stability of ACP52C, 4 types of albumin-affinity C.sub.16 fatty acid (palmitoyl acid)-conjugated peptides were synthesized (
[Example 2] Confirmation of In Vitro Anticancer Effect of CP2c-Targeting Peptide-Fatty Acid Conjugate
[0080] The anticancer effect of the CP2c-targeting peptide-fatty acid conjugate synthesized in Preparation Example 2 was analyzed in various cancer cells. As a result, all three types of C.sub.16 fatty acid-binding peptides {ACP52CG (=ACP52CG-E), ACP52CK (=ACP52CG-GFLGE), and ACP52CGK} induced cancer cell-specific cell death similarly to the control group (ACP52C), and the GI.sub.50 values calculated at 48 hours after treatment were like or more efficient than that of the control (
[Example 3] Confirmation of Tumor Growth Inhibitory Effect and General Physiological Toxicity Dependent Upon Treatment with CP2c-Targeting Peptide-Fatty Acid Conjugates in Mouse Models Transplanted with Various Cancer Cell Lines
[0081] [3-1] Confirmation of Tumor Growth Inhibitory Effect and General Physiological Toxicity of ACP52CG (=ACP52CG-E), ACP52CK (=ACP52CG-GFLGE), and ACP52GK (=C16-ACP52cm) in Mouse Models Transplanted with Liver and Breast Cancer Cell Lines
[0082] To analyze the anticancer efficacy of the CP2c target peptide-fatty acid conjugates synthesized in Preparation Example 2 in animal models, ACP52CG and ACP52CK were injected into the Hep3B xenograft mice via tail vein 5 times at 3-day intervals. As a result, both ACP52CG and ACP52CK showed similar efficacy to sorafenib, but their efficacy was inferior to that of ACP52C. However, no specific abnormalities were found in normal tissues and blood levels, and no toxicity was observed (
[0083] In addition, the mice that passed 22 weeks after DEN treatment were classified into 3 groups (7 to 8 mice/group), such as a control group (mock) treated with only a vehicle, a sorafenib group (an approved drug for liver cancer treatment), and an ACP52CG-GFLGE (ACP52CK) group. The drug was injected through the tail vein a total of 12 times at a concentration of 5 mg/kg at 3-day intervals. As a result of the analysis, the sorafenib treatment group showed a significant anticancer effect (p=0.04) compared to the control group, and the ACP52CG-GFLGE (ACP52CK) treatment group showed a similar anticancer effect (p=0.001) to the sorafenib treatment group (
[0084] When ACP52CG and ACP52CK were injected into MDA-MB-231 (LM1) xenograft mice via tail vein 5 times at 3-day intervals, both ACP52CG and ACP52CK showed tumor regression efficacy, but the anticancer effect was not significant. No specific abnormalities were found in blood levels, so toxicity was not observed (
[0085] When ACP52GK (=C16-ACP52 cm) was injected into Hep3B xenograft mice via tail vein 5 times at 3-day intervals, and then the efficacy was analyzed, it was confirmed that the ACP52GK efficacy was lower than that of ACP52C, but the effect was superior to that of the control FQI1 group.
[0086] [3-2] Confirmation of Tumor Growth Inhibitory Effect, Metastasis Inhibition Effect, and General Physiological Toxicity of ACP52CGK in Mouse Models Transplanted with Liver and Breast Cancer Cell Lines
[0087] ACP52CGK was injected into the Hep3B xenograft mice via tail vein at 3 different concentrations (1.39, 2.77, or 5.54 mg/kg) 5 times at 3-day intervals. The tumor volume was measured at every three days after drug injection. The tumor and major tissues were excised from the mice sacrificed on the 24th day after the tumor cell injection. The tumor was weighed and fixed with 4% formaldehyde together with major organs. After making tissue slides through paraffin sections, hematoxylin/eosin staining was performed. The collected blood samples were subjected to basic CBC analysis using a Coulter LH 750 hematology analyzer. The acquired data were statistically processed using an Excel program.
[0088] As a result, ACP52CGK exhibited a tumor suppressive effect similar to that of ACP52C, and no abnormalities were found in normal tissues and blood levels (
[0089] ACP52CGK was injected into Hep3B xenograft mice via tail vein 5 times at intervals of 5 days at 3 different concentrations (1.39, 2.77, 5.54 mg/kg), and the anticancer effect was evaluated in the same manner as described above. As a result, all three concentrations of ACP52CGK showed tumor inhibition and metastasis inhibition effects superior to the sorafenib and ACP52C treatment groups, and the inhibition effects were concentration-dependent (
[0090] The anticancer effect of ACP52CGK was analyzed in MDA-MB-231 (LM1) xenograft mice in the same manner as in the Hep3B xenograft mouse model experiments. Similarly, tumor suppression and metastasis inhibition effects were superior to those of the sorafenib and ACP52C-treated groups at all three concentrations (1.39, 2.77, or 5.54 mg/kg) of ACP52CGK (
[Example 4] Stability and Safety Evaluation of CP2c-Targeting Peptide-Fatty Acid Conjugates
[0091] To analyze the in vivo half-life of ACP52CGK, Cy5-labeled ACP52CGK was injected into the tail vein of the mouse, and then the fluorescence intensity remaining in the mouse body was measured over time by live imaging process. As a result, the half-life was about 20.2 hours (
[0092] To analyze the subcellular movement, localization, and stability of ACP52CGK in cultured cells, Cy5-labeled ACP52CGK was treated in cell culture media for 30 minutes, and then the subcellular movement of the peptide was traced over time. In addition, subcellular movement was analyzed by confocal microscope whether Cy5-labeled ACP52CGK also migrated into mitochondria (Hsp60) and lysosomes (LC3). As a result, ACP52CGK passed through the cytoplasm and was located mostly in the nucleus from 4 hours, and came out of the cytoplasm after 8 hours; some thereof was in the mitochondria, but eventually migrated to the lysosome and degraded at 16 hours. These subcellular movement, localization, and stability phenomena of ACP52CGK were not different from those in ACP52C (
[0093] Meanwhile, it was speculated that the ACP52C would not exhibit immunogenicity since it is consisting of 15 amino acids. To verify this, immunogenicity of ACP52CG and ACP52CK was directly tested in the process of deriving the final new drug candidate. Since the final candidate material might be a C-16 palmitoyl acid-conjugated ACP52C peptide, which is not different with ACP52CG and ACP52CK in terms of chemical composition, it was decided to analyze whether antibodies were formed on ACP52CG and ACP52CK. As a result of performing ELISA analysis on sera isolated from rabbits injected with ACP52CG and ACP52CK three times, both rabbit sera did not induce immune responses in ACP52CG, ACP52CK, and ACP52CGK, including ACP52C. Therefore, it was concluded that the final candidate material (ACP52CGK) would also not show immunogenicity in the human body (
[0094] A repeated toxicity test for the in vivo administration of ACP52CGK was conducted using female and male mice. As a preliminary experiment, when 100 mg/kg and 1000 mg/kg of ACP52C were repeatedly administered twice, all the mice survived, and any liver toxicity or adverse effect on major organs was not observed. As a full-scale experiment, after intravenous infusion of ACP52CGK for 28 days at 3-day intervals into the solvent group and high-dose group (100 mg/Kg) of 6 males and females each, the weight change, drinking water intake, and main histological analysis of organs, organ weight, hematological tests and blood biochemical tests were analyzed. Overall, no abnormal findings were detected (
TABLE-US-00002 TABLE 1 Absolute organ weights (g) of mice treated or non-treated with ACP52CGK Female (ACP52Cm, 100 Male (ACP52Cm, Female (vehicle) mg/kg) Male (vehicle) 100 mg/kg) Liver 0.8000 ± 0.0353 0.8049 ± 0.0350 0.9050 ± 0.0732 0.9011 ± 0.0916 Kidney 0.2305 ± 0.0124 0.2417 ± 0.0184 0.3188 ± 0.0174 0.3055 ± 0.0220 Adrenal Gland 0.0045 ± 0.0014 0.0059 ± 0.0009 0.0046 ± 0.0014 0.0040 ± 0.0013 Spleen 0.0625 ± 0.0070 0.0620 ± 0.0051 0.0604 ± 0.0076 0.0573 ± 0.0084 Ovary (Testis) 0.0046 ± 0.0016 0.0059 ± 0.0012 0.1863 ± 0.0083 0.1693 ± 0.0169 Uterus 0.0503 ± 0.0188 0.0638 ± 0.0227 0.0518 ± 0.0052 0.0482 ± 0.0127 (Epididymis) Lung 0.1423 ± 0.0182 0.1432 ± 0.0075 0.1411 ± 0.0186 0.1476 ± 0.0105 Thymus 0.0394 ± 0.0055 0.0338 ± 0.0022 0.0402 ± 0.0127 0.0408 ± 0.0144 Heart 0.0919 ± 0.0097 0.0950 ± 0.0072 0.1072 ± 0.0066 0.1078 ± 0.0087 Brain 0.4077 ± 0 0196 0.4034 ± 0.0291 0.4013 ± 0.0157 0.3943 ± 0.0168
TABLE-US-00003 TABLE 2 Relative organ weights (%) of mice treated or non-treated with ACP52CGK Female (ACP52Cm, 100 Male (ACP52Cm, Female (vehicle) mg/kg) Male (vehicle) 100 mg/kg) Liver 4.45 ± 0.17 4.47 ± 0.14 4.17 ± 0.25 4.41 ± 0.41 Kidney 1.28 ± 0.06 1.34 ± 0.06 1.47 ± 0.09 1.50 ± 0.08 Adrenal Gland 0.0250 ± 0.0076 0.0324 ± 0.0047 0.02 ± 0.01 0.02 ± 0.01 Spleen 0.35 ± 0.04 0.35 ± 0.03 0.28 ± 0.03 0.28 ± 0.04 Ovary (Testis) 0.0255 ± 0.0087 0.0326 ± 0.0054 0.86 ± 0.05 0.83 ± 0.08 Uterus 0.28 ± 0.10 0.35 ± 0.12 0.24 ± 0.02 0.24 ± 0.07 (Epididymis) Lung 0.79 ± 0.10 0.79 ± 0.03 0.65 ± 0.07 0.72* ± 0.05 Thymus 0.22 ± 0.03 0.19 ± 0.02 0.19 ± 0.06 0.20 ± 0.06 Heart 0.51 ± 0.04 0.53 ± 0.03 0.49 ± 0.03 0.53 ± 0.04 Brain 2.27 ± 0.12 2.24 ± 0.18 1.85 ± 0.05 1.93 ± 0.12
TABLE-US-00004 TABLE 3 Hematology of mice treated or non-treated with ACP52CGK Female (ACP52Cm, 100 Male (ACP52Cm, Female (vehicle) mg/kg) Male (vehicle) 100 mg/kg) WBC (10.sup.3/ul) 2.26 ± 0.15 2.34 ± 0.62 2.42 ± 0.98 2.83 ± 1.04 Neutrophils (%) 16.33 ± 5.14 17.77 ± 0.91 18.17 ± 2.59 25.83 ± 12.58 Eosinophils (%) 14.47 ± 5.42 14.83 ± 1.7 3.83 ± 1.76 6.70 ± 2.17 Basophils (%) 0.97 ± 0.31 1.20 ± 0.66 1.30 ± 0.90 0.73 ± 0.38 Lymphocytes (%) 66.57 ± 1.92 65.23 ± 0.91 75.10 ± 5.12 65.53 ± 13.98 Monocytes (%) 1.27 ± 0.32 1.07 ± 0.06 0.93 ± 0.71 0.77 ± 0.67 RBC (10.sup.6/ul) 9.66 ± 0.45 9.91 ± 0.08 10.59 ± 0.29 10.39 ± 1.39 Hematocrit (%) 54.80 ± 4.30 54.50 ± 1.47 57.50 ± 1.71 58.30 ± 9.33 Hemoglobin (g/dl) 14.67 ± 0.32 14.93 ± 0.50 16.07 ± 0.45 15.53 ± 2.18 MCV (fl) 56.53 ± 0.32 55.00 ± 1.64 54.33 ± 1.47 56.00 ± 2.30 MCH (pg) 17.03 ± 1.70 15.07 ± 0.49 15.17 ± 0.12 14.97 ± 0.15 MCHC (g/dl) 28.60 ± 2.12 27.43 ± 0.32 27.97 ± 0.61 26.70 ± 0.80 Platelets (10.sup.3/ul) 892.67 ± 111.54 906.33 ± 145.82 964.33 ± 125.51 1038 ± 30.51
TABLE-US-00005 TABLE 4 Serum biochemistry of mice treated or non-treated with ACP52CGK Female (ACP52Cm, 100 Male (ACP52Cm, Female (vehicle) mg/kg) Male (vehicle) 100 mg/kg) ALT (U/l) 11.53 ± 1.68 13.93 ± 3.23 45.40 ± 10.18 23.20 ± 5.94 AST (U/l) 66.67 ± 9.28 68.37 ± 5.46 96.00 ± 7.06 93.30 ± 19.39 T-proteins (g/dl) 4.50 ± 0.10 4.63 ± 0.55 4.77 ± 0.32 4.43 ± 0.35 Albumin (g/dl) 3.33 ± 0.06 3.20 ± 0.17 2.93 ± 0.12 2.73 ± 0.25 Cholesterol 82.73 ± 4.53 79.60 ± 8.56 99.13 ± 11.12 90.63 ± 2.97 (mg/dl) Triglycerides 23.43 ± 6.55 18.90 ± 12.34 22.25 ± 25.39 23.67 ± 6.43 (mg/dl) HDL (mg/dl) 40.03 ± 2.30 39.47 ± 4.97 77.50 ± 23.19 72.85 ± 7.42 LDL (mg/dl) 4.77 ± 0.90 4.43 ± 0.91 4.10 ± 0.35 3.57 ± 0.23 BUN (mg/dl) 27.70 ± 4.19 26.50 ± 3.32 31.83 ± 17.33 23.53 ± 4.76 Creatinine 0.35 ± 0.01 0.36 ± 0.02 0.37 ± 0.03 0.37 ± 0.03 (mg/dl) LDH (U/l) 147.70 ± 17.08 141.10 ± 44.08 308.33 ± 73.74 357.73 ± 91.87
[0095] To investigate whether the efficacy of ACP52CGK tested on cancer cell lines and xenograft mouse models can be equally applied in actual clinical practice, the efficacy of ACP52CGK was evaluated in cells cultured from the tumor tissue of breast cancer patients in a fresh state. As a preliminary result, it was confirmed that ACP52CGK induces cell death at GI.sub.50: ˜2 μM, similar to those in the cancer cell line experiments (
[Example 5] Analysis of Resistance Causation of Cells Exhibiting Resistance to CP2c-Target Peptide-Fatty Acid Conjugate
[0096] As a result of analyzing the efficacy of ACP52CGK in cells primary cultured from PDX (patient derived xenograft) tumor tissue for each generation, it was confirmed that the sensitivity to ACP52CGK was not significantly different in cells derived from the same origin (
[0097] The cells exhibiting resistance to ACP52CGK (mainly lung cancer cell lines) tended to show a low expression level of MDM2p90 and a relatively high expression of MDM2p60. In fact, it was confirmed by immunoblot that the expression of YY1 was decreased in the three lung cancer cell lines (A549, PC9, KCL22) treated with ACP52C, but the expression of p53, p63 and p73 did not show any change. There was no decrease in the expression of MDM2 (p90 and p60) in these cell lines. Since MDM2p60 is known to be a protein in which the C-terminal region of MDM2p90 comprising sites (S386, S395, and S407) phosphorylated by ATM is deleted, it was speculated that the MDM2 degradation would not be properly regulated by ACP52C treatment (
[0098] Two models have been proposed that the generation of MDM2p60 is due to caspase2 cleavage of MDM2p90 or alternative splicing. When we performed RT-PCR using a primer set capable of detecting an alternative splicing form of MDM2 in various cancer cell lines, a lung cancer cell-specific splice form was not found. In addition, when we tested the nucleotide sequence analysis of genomic DNA after PCR cloning to determine whether MDM2p60 is generated from the truncated mRNA due to the presence of SNPs in the MDM2 gene specifically for lung cancer cell lines, lung cancer cell-specific SNPs were not observed (
[0099] Meanwhile, when a caspase2 inhibitor (AC-VDVAD-CHO) was treated to identify a phenomenon that occurs due to the high activity of caspase2 specifically in lung cancer cells, it was found by immunoblot that the protein amount of MDM2p90 increased, while the protein amount of MDM2p60 decreased according to the treatment with the Caspase2 inhibitor. Therefore, we concluded that the MDM2p60 form, which is overexpressed in lung cancer cells, is the result of cleavage of MDM2p90 by caspase2. Based on these results, the cell death-inducing effect was analyzed by treating cells (A549 and PDX cells; Breast FO-JOS), which showed resistance to ACP52C, with a combination of caspase 2 inhibitor and ACP52C. As a result, efficacy was observed around GI.sub.50˜1 μM in the group treated with the combination of the caspase 2 inhibitor and ACP52C (
[0100] Therefore, the ACP52CGK peptide improved in vivo stability compared to the existing ACP52C peptide and showed growth inhibition/cell death in all carcinoma cells as in ACP52C, but had no significant effect on normal cells. In addition, it was confirmed that cancer cells exhibiting resistance to ACP52C could be killed by the combined treatment of ACP52C with a caspase 2 inhibitor.