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）是提取自虎杖（Polygonum cuspidatum）的小分子化合物，具备多种生物学活性，其中抗肿瘤作用尤为突出。然而，目前尚未有研究探讨虎杖苷在肝细胞癌（hepatocellular carcinoma, HCC）中的抗肿瘤活性。本研究通过MTT比色法（MTT assay）、溴脱氧尿苷掺入实验（BrdU assay）、Transwell侵袭实验（transwell invasion assay）以及划痕愈合实验（wound healing assay），检测肝细胞癌细胞的增殖、侵袭与迁移能力；采用流式细胞术（Flow cytometry）与TUNEL染色法（TUNEL assay）检测细胞凋亡情况；利用实时荧光定量PCR（quantitative real-time PCR）与蛋白质免疫印迹实验（western blotting）检测mRNA与蛋白质的表达水平；通过异种移植瘤实验（xenograft experiment）探究虎杖苷的体内抗肿瘤效果；并采用免疫组化染色（immunostaining）分析半胱氨酸天冬氨酸蛋白酶3（caspase-3）与Ki-67的表达情况。实验结果显示，虎杖苷可呈浓度与时间依赖性抑制肝细胞癌细胞系的细胞增殖。虎杖苷还可呈浓度依赖性诱导细胞凋亡，其机制可能与提升半胱氨酸天冬氨酸蛋白酶3（caspase-3）活性、上调半胱氨酸天冬氨酸蛋白酶9（caspase-9）与Bax（Bcl-2相关X蛋白）的蛋白表达，同时下调Bcl-2（B细胞淋巴瘤/白血病-2）的蛋白表达有关。此外，虎杖苷处理可抑制肝细胞癌细胞系的细胞增殖、侵袭与迁移能力。虎杖苷处理还可抑制肝细胞癌细胞内的Wnt/β-连环蛋白（Wnt/beta-catenin）信号通路活性。虎杖苷处理可显著降低接种HepG2细胞的裸鼠体内的肿瘤生长速度，抑制Ki-67的表达，同时提升caspase-3的表达与TUNEL活性。本研究数据表明，虎杖苷在抑制肝细胞癌进展过程中发挥重要作用。