본 연구는 녹차폴리페놀이 시스플라틴의 항암작용과 신장독성에 미치는 영향을 유방암 세포(EMT6)와 암세포 이식 마우스를 이용하여 in vitro와 in vivo 실험으로 관찰하였다. 배양한 EMT6 세포에서 녹차폴리페놀은 시스플라틴에 의한 세포 독성을 증가시켰다. 마우스에 EMT6 세포를 주사하여 유발된 종양의 크기가 시스플라틴군(CP)보다 시스플라틴+녹차폴리페놀군(CP+GTP)에서 유의하게 작았고, 종양조직 p53와 caspase-3 활성화가 시스플라틴군(CP)보다 시스플라틴+녹차폴리페놀군(CP+GTP)에서 유의하게 높았으며, 신장 GGT와 AP 활성은 시스플라틴군(CP)보다 시스플라틴+녹차폴리페놀군(CP+GTP)에서 유의하게 높았고, 신장 조직학적 소견에서 신세뇨관 확장과 괴사가 시스플라틴군(CP)보다 시스플라틴+녹차폴리페놀군(CP+GTP)에서 유의하게 낮았다. 이상의 결과 녹차폴리페놀은 EMT6 유방암 세포를 이용한 in vitro 및 in vivo 실험에서 시스플라틴의 항암작용을 증강시키면서 신장에 대한 독성 부작용은 감소시키는 효과가 있는 것으로 추측된다. 녹차폴리페놀의 시스플라틴 항암작용 증강과 신장 독성 억제 및 감소 효과는 시스플라틴에 의한 암 치료 시 화학요법제의 보조제로서 이용가치가 있는 것으로 생각되며, 항암화학요법제에 대한 보조제로의 개발을 위해서는 대규모 동물실험을 통한 효과 입증 및 부작용에 대한 실험과 임상연구가 뒷받침되어야 할 것으로 사료된다.
The aim of this study is to evaluate the effects of green tea polyphenol (GTP) on anticancer treatment with cisplatin (CP), using both an in vitro cell culture model and an in vivo mouse model of established breast tumor. Mouse breast cancer cells (EMT6) were treated with or without GTP and CP followed by determination of the cell viability using an MTT assay. The relative cell viability of CP treated EMT6 cells was 96% at a 20 μg/mL concentration of cisplatin; however, in combination with GTP (50 μg/mL), the cell viability decreased to 20% at the same concentration of CP (20 μg/mL). For the in vivo study, EMT6 cells were inoculated into Balb/c mice for the establishment of a tumor-bearing mice model. The tumor-bearing mice were treated with CP (5 mg/kg. i.p.) with or without dietary GTP (0.2% drinking water). Tumor growth was monitored by a measurement of tumor size using a digital caliper, and nephrotoxicity was determined by enzymatic and histological examinations. The levels of p53 and caspase-3 in tumor tissues were examined by a Western blot. In tumor-bearing mice treated with GTP plus CP, the increment of tumor volume showed a significant reduction, compared with CP or GTP alone. The levels of p53 and cleaved caspase-3 (caspase-3/p17) in tumor tissues of tumor-bearing mice were increased by CP and GTP compared to CP alone. In CP treated tumor-bearing mice, γ-glutamyltranspeptidase (GGT) and alkaline phosphatase (AP) activities were decreased, and marked tubular necrosis and dilatation were observed in the kidney. CP-induced enzymatic and histopathological changes in the kidney of tumor-bearing mice were reduced by combinations of GTP with CP. The results of these experiments demonstrated that dietary GTP has a potentiating effect on CP anti-tumor activity and a protective effect against CP-induced renal dysfunction. Therefore, GTP may be used as a modulator in anticancer treatment with CP.