大腸癌 細胞에서 시스플라틴의 細胞毒性에 미치는 카테킨의 影響

Abstract

ABSTRACT

The effect of catechin on cisplatin-induced cytotoxicity in colon cancer cells

Jeong Seung-Wook Advisor : Prof. Lee Byoung-Rai, M.D., Ph.D. Department of Medicine, Graduate School of Chosun University

Objective: Cisplatin used as a effective chemotherapeutic agents for treatment solid tumor, but clinical use of this agent limited to it's toxicity. In this study, I evaluated catechin as a biochemical modulator on the tumor suppressive effects of cisplatin in treatment of colon cancer. Methods: The human colon cancer cell(HCT116) and mouse colon cancer cell(CT26.WT) lines were used. HCT116 and CT26.WT cells(ATCC) were grown in RPMI-1640 medium supplemented with 10% (v/v) heat-inactivated fetal bovine serum and antibiotics: 100 units/mL penicillin and 100 μg/mL streptomycin. Two types of catechin, epigallocatechin galate(EGCG) and polyphenon(mixture of catechin) were used for these experiment. Cells were seeded at 1×104 cells/well in RPMI1640 media in triplicate wells on a Nunc Lab ware 96 well flat bottom microculture plate, with or without catechin(50ug/mL) and at different concentrations of cisplatin(0-100ug/mL). The 1 day after incubation at 37°C in 5% CO2, the cells viability were determined using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay. Western blot method were employed to detect the influence of EGCG and polyphenon on the expressions of p53, and caspase 8 genes in CT26.WT cells. Influence of catechin on therapeutic efficacy of cisplatin was evaluated in Balb/c mice with CT26.WT cell inoculation. The cisplatin(5mg/kg) and polyphenon(50mg/kg) were injected intraperitoneally to CT26.WT cell-inoculated mice and tumor size measured by caliper. Results: HCT116 cells viability were decreased to 62% at a 4 ug/mL concentration of cisplatin, and to 25 % above 6 ug/mL as measured by the MTT assay. However, in the co-treatment with EGCG(50ug/mL) or polyphenon(50ug/mL) the cell viability decreased to 31% at 2 ug/mL of cisplatin and to 11 % at 4 ug/mL of cisplatin in HCT116 cells. CT26.WT cells viability were decreased to 73% at a 4 ug/mL concentration of cisplatin, but cell viability decreased to 20% and 21% at 4 ug/mL of cisplatin in EGCG(50ug/mL) or polyphenon(50ug/mL) co-treated CT26.WT cells as measured by the MTT assay. There is no apparent changes in cisplatin-induced cytotoxicity in between EGCG and polyphenon administration. The levels of p53 and caspase-8 in HCT116 cells were not changed by EGCG treatment. Tumor size of Balb/C mice was significantly decreased in cisplatin+polyphenon treatment compared with cisplatin or polyphenon treatment groups. Conclusion: These experiments showed that catechin has a potentiating effect on cisplatin-induced cytotoxicity of colon cancer cells. Therefore, the catechin may be candidate for modulator for anticancer treatments with cisplatin.

Key words: Catechin, cisplatin, CT26.WT cell, HCT116 cell.