探討薑黃素結合臨床抗癌藥物在人類膀胱癌細胞中之效果及機轉

Abstract

膀胱癌是泌尿系統中最常見的腫瘤疾病，可能與環境中砷暴露量較高而導致Aurora A過度表現有關。膀胱癌中發現Aurora A及表皮生長因子（EGF）有過度活化的情形，跟細胞增生有關。FDA核准的臨床藥物以Gemcitabine搭配Cisplatin/Carboplatin是目前傾向使用的化療藥物。希望將臨床藥物搭配薑黃素，藉由抑制Aurora A基因及相關蛋白表現，延緩癌細胞生長。以MTT assay決定各臨床藥物作用在膀胱癌T24細胞的濃度為0.05~0.1 μM Gemcitabine加0.5 μM Cisplatin/ 5 μM Carboplatin。結合薑黃素15 μM計算出CI值皆呈現協同作用。以流式細胞儀分析細胞週期，臨床用藥結合薑黃素增加代表細胞凋亡比例sub-G1 phase，增加代表可能跟抑制Aurora A相關G2/M phase停滯的比例，而且同時會引起細胞自噬作用。以西方墨點法發現薑黃素合併使用臨床藥物，抑制phospho-Aurora A、p62、Beclin-1、phospho-PI3K、phospho-p70s6k、Atg12-Atg5等蛋白表現，增加LC3-II、phospho-mTOR、phospho-AKT、phospho-MEK、phospho-ERK等蛋白表現。綜合以上結果，薑黃素合併臨床用藥能增加膀胱癌T24細胞毒殺效果及增加sub-G1期凋亡比例，增加化療敏感性，且抑制T24細胞Aurora A的活性，經由活化MEK/ERK路徑而促進自噬作用。

Bladder cancer is the ninth most common cancer worldwide and the fourteenth most diagnosed malignancy in Taiwan (2013). Gemcitabine plus cisplatin (GC) treatment is prefered for nowadays treatment. For patients with impaired renal function, gemcitabine plus carboplatin (GCa) treatment is recommended. Overexpressions of Aurora A kinase and epidermal growth factor (EGF) were observed in bladder cancer cells. Our previously data demonstrate that curcumin significantly inhibited Aurora A gene expression, in part caused failure of various mitotic events and G2/M arrest of human bladder cancer cells. In this study, human bladder cancer T24 cells were treated with the existing chemotherapy (GC or GCa) in the presence and absence of curcumin. Addition of curcumin not only produced synergism using combination index analysis, but also raised the percentages of phases in sub-G1 (apoptosis rate) and G2/M using flow cytometry. Combinatio of cucurmin induced autophagy. Decreasing of phospho-Aurora A, p62, Beclin-1, phospho-PI3K, phospho-p70s6k, Atg12-Atg5 and increasing of LC3-II, phospho-mTOR, phospho-AKT, phospho-MEK, phospho-ERK were observed. Taken together, clinical drugs combined with curcumin not only inhibited activity of aurora a, but also promoted apoptosis and autophagy in T24 cells.