Polydatin inhibits cell proliferation, invasion and migration, and induces cell apoptosis in hepatocellular carcinoma

Polydatin, a small molecule from Polygonum cuspidatum, has many biological functions, particularly anti-cancer effects. However, the anti-cancer effects of polydatin in hepatocellular carcinoma (HCC) have not been examined yet. In the present study, MTT assay, BrdU assay, transwell invasion assay, and wound healing assay were performed to determine cell proliferation, invasion and migration. Flow cytometry and TUNEL assay were used to measure cell apoptosis. Quantitative real-time PCR and western blotting assays were used to determine mRNA and protein expression levels. Xenograft experiment was performed to determine the in vivo anti-tumor effect of polydatin. Immunostaining was performed to analyze the expression of caspase-3 and Ki-67. Our results showed that polydatin inhibited cell proliferation in a concentration-dependent and time-dependent manner in the HCC cell lines. Polydatin also induced cell apoptosis in a concentration-dependent manner possibly via increasing the caspase-3 activity, and up-regulating the protein expression of caspase-3, caspase-9, Bax, and down-regulating the protein expression of Bcl-2. In addition, polydatin treatment had an inhibitory effect on cell proliferation, invasion and migration in HCC cell lines. Polydatin treatment also suppressed the Wnt/beta-catenin signaling activities in HCC cells. Polydatin treatment significantly reduced tumor growth in nude mice inoculated with HepG2 cells, suppressed the expression of Ki-67, and increased caspase-3 expression and TUNEL activity. Our data indicated the important role of polydatin for the suppression of HCC progression.

虎杖苷（Polydatin）是从虎杖（Polygonum cuspidatum）中提取的小分子化合物，具备多种生物学活性，尤以抗肿瘤效应见长。但目前尚无研究探究虎杖苷在肝细胞癌（hepatocellular carcinoma, HCC）中的抗肿瘤作用。本研究通过MTT实验、BrdU实验、Transwell侵袭实验及划痕愈合实验，评估细胞增殖、侵袭及迁移能力；借助流式细胞术与TUNEL染色法检测细胞凋亡情况；采用实时定量PCR与蛋白质印迹（western blotting）实验检测mRNA与蛋白的表达水平；开展异种移植瘤实验以明确虎杖苷的体内抗肿瘤活性；采用免疫染色法分析胱天蛋白酶-3（caspase-3）与Ki-67的表达情况。研究结果显示，虎杖苷可呈浓度与时间依赖性抑制肝癌细胞系的增殖；虎杖苷还可通过浓度依赖性方式诱导细胞凋亡，其潜在机制可能为提升胱天蛋白酶-3活性，上调胱天蛋白酶-3、胱天蛋白酶-9及Bax的蛋白表达，同时下调Bcl-2的蛋白表达。此外，虎杖苷处理可显著抑制肝癌细胞系的增殖、侵袭与迁移能力；虎杖苷处理还可抑制肝癌细胞中Wnt/β-连环蛋白（Wnt/beta-catenin）信号通路的活性。在接种HepG2细胞的裸鼠体内，虎杖苷处理可显著抑制肿瘤生长，下调Ki-67的表达，上调胱天蛋白酶-3的表达并提升TUNEL染色阳性率。本研究数据表明，虎杖苷在抑制肝细胞癌进展中发挥关键作用。