Wang Wei, Li Youran, Chen Yiqi, Chen Hongjin, Zhu Ping, Xu Minmin, Wang Hao, Wu Minna, Yang Zhijian, Hoffman Robert M, Gu Yunfei
Nanjing University of Chinese Medicine, Nanjing, P.R. China.
Department of Colorectal Surgery, Jiangsu Province Hospital of TCM, Nanjing, P.R. China.
Anticancer Res. 2018 Apr;38(4):1917-1925. doi: 10.21873/anticanres.12429.
BACKGROUND/AIM: The aim of the present study was to investigate the efficacy of an ethanolic extract of gamboge (EEG), a traditional Chinese medicine (TCM), both in vitro on colon cancer cells and in vivo in an orthotopic mouse model of human colon cancer.
The in vitro cytotoxicity of EEG on colon cancer cells was determined with the CCK8 proliferation assay and the Annexin V-PE/7-AAD apoptosis assay. Efficacy of EEG in vivo was evaluated in an orthotopic mouse model of human colon cancer implated with the green fluorescent protein-expressing human colon cancer cell line SW480-GFP. The tumor-bearing mice were treated with vehicle (0.2 ml/dose normal saline, po, daily), irinotecan (50 mg/kg/dose, ip, twice a week), 5-FU (15 mg/kg/dose, ip, every other day) as positive controls or EEG at doses of 12.5, 25 and 50 mg/kg/dose, po, daily. Real-time fluorescence imaging was performed to determine tumor inhibition in each treated group compared to the untreated controls. The protein expression of β-catenin, MMP-7, cyclin D1 and E-cadherin in the tumors was analyzed by immunohistochemistry.
EEG significantly induced proliferation inhibition and apoptosis of SW480 colon cancer cells in vitro in a dose-dependent manner. Tumor growth in the colon-cancer orthotopic model was significantly inhibited by irinotecan, 5-FU and all three doses of EEG. The efficacy of EEG was comparable to irinotecan and 5-FU. Irinotecan, 5-FU and 50 mg/kg EEG significantly decreased the protein expression of β-catenin and MMP-7. Cyclin D1 expression was decreased and E-cadherin expression was increased by irinotecan, 5-FU and all three doses of EEG.
The present study demonstrates anti-tumor efficacy of EEG on colon cancer both in vitro and in vivo through inducing proliferation inhibition and apoptosis of SW480 colon cancer cells and inhibiting tumor growth, respectively. EEG exerts anti-tumor activity at least partly via down-regulation of the Wnt/β-catenin signaling pathway.
背景/目的：本研究旨在探讨中药藤黄乙醇提取物（EEG）在体外对结肠癌细胞以及在人结肠癌原位小鼠模型中的体内疗效。
采用CCK8增殖试验和Annexin V-PE/7-AAD凋亡试验测定EEG对结肠癌细胞的体外细胞毒性。在接种表达绿色荧光蛋白的人结肠癌细胞系SW480-GFP的人结肠癌原位小鼠模型中评估EEG的体内疗效。荷瘤小鼠分别接受溶剂（0.2 ml/剂量生理盐水，口服，每日）、伊立替康（50 mg/kg/剂量，腹腔注射，每周两次）、5-氟尿嘧啶（15 mg/kg/剂量，腹腔注射，隔日一次）作为阳性对照，或EEG 12.5、25和50 mg/kg/剂量，口服，每日。与未处理的对照组相比，进行实时荧光成像以确定各治疗组的肿瘤抑制情况。通过免疫组织化学分析肿瘤中β-连环蛋白、基质金属蛋白酶-7、细胞周期蛋白D1和E-钙黏蛋白的蛋白表达。
EEG在体外显著诱导SW480结肠癌细胞增殖抑制和凋亡，呈剂量依赖性。伊立替康、5-氟尿嘧啶和所有三个剂量的EEG均显著抑制结肠癌原位模型中的肿瘤生长。EEG的疗效与伊立替康和5-氟尿嘧啶相当。伊立替康、5-氟尿嘧啶和50 mg/kg EEG显著降低β-连环蛋白和基质金属蛋白酶-7的蛋白表达。伊立替康、5-氟尿嘧啶和所有三个剂量的EEG均使细胞周期蛋白D1表达降低，E-钙黏蛋白表达增加。
本研究表明，EEG通过分别诱导SW480结肠癌细胞增殖抑制和凋亡以及抑制肿瘤生长，在体外和体内均对结肠癌具有抗肿瘤疗效。EEG至少部分通过下调Wnt/β-连环蛋白信号通路发挥抗肿瘤活性。
