目的:探讨组蛋白去乙酰化酶（histone deacetylase，HDAC）抑制剂丙戊酸（valproic acid，VPA）对结肠癌细胞上皮-间质转化（epithelial-mesenchymal transition，EMT）的作用。方法：以结肠癌细胞系DLD-1、HCT116、SW480 和HT29 为研究对象，用MTT法检测不同浓度（0.5、5 mmol/L) VPA对结肠癌细胞增殖的影响，用Western blotting 检测细胞EMT相关蛋白上皮钙黏蛋白（E-cadherin）和波形蛋白（vimentin）的表达水平，免疫荧光染色法检测上皮钙黏蛋白和波形蛋白表型的变化，划痕愈合与Transwell侵袭实验检测结肠癌细胞的迁移与侵袭能力。结果：不同浓度VPA作用4 种结肠癌细胞48 h，低浓度VPA（0.5 mmol/L）对4 种结肠癌细胞增殖几乎无影响，取0.5 mmol/L为实验浓度。0.5 mmol/L VPA作用后，结肠癌细胞上皮钙黏蛋白表达水平显著下降（P<0.05）但波形蛋白表达水平显著升高（P<0.05）；0.5 mmol/L VPA处理组细胞的上皮钙黏蛋白出现膜衰减和核移位，以及波形蛋白含量显著增加，上述反应在6 h 后开始且可维持24 h；0.05 mmol/L的VPA处理可增强结肠癌细胞的迁移和侵袭能力。结论：低浓度VPA可通过上皮钙黏蛋白的核移位诱导结肠癌细胞EMT的发生且明显增强细胞的迁移侵袭能力，因此在结肠癌中选择HDAC抑制剂作为一个新型抗癌药物之前应谨慎。

Objective: To explore the effect of histone deacetylase (HDAC) inhibitor valproic acid (VPA) on the epithelial-mesenchymal transition (EMT) of colon cancer. Methods: With four colon carcinoma cell lines (DLD-1, HCT116, SW480 and HT29) as study subjects, the effect of different concentrations of VPA (0.5，5 mmol/L) on cell proliferation was detected by MTT assay. The expression level of EMT-related proteins (E-cadherin and vimentin) was detected by Western blotting; Phenotypic changes of E-cadherin and vimentin were detected by immunofluorescence staining; Cell migration and invasion ability was detected by wound healing and Transwell invasion assay, respectively. Results: After treated with different concentrations of VPA for 48 h, low concentration of VPA merely exerted any effect on the cell proliferation rate of four colon cancer cell lines, and thus was chosen as the experiment concentration;The results of Western blotting showed that the expression of E-cadherin was reduced (P<0.05) and vimentin was increased (P<0.05) in colon carcinoma cells by VPA treatment (0.5 mmol/L); Immunofluorescence staining revealed membranous attenuation or nuclear translocation of E-cadherin and enhanced expression of vimentin after VPA treatment (0.5 mmol/L), and these responses occurred after 6 h and sustained until 24 h; Wound healing and Transwell invasion assay showed increased migration and invasion ability following VPA treatment (0.5 mmol/L). Conclusion: Low concentration VPA could induce the development of EMT in colon cancer cells by nuclear translocation of E-cadherin, and obviously enhance the migration and invasion ability of colon cancer cells; Thus, HDAC inhibitors, as a new type anti-cancer option, shall be carefully considered before their application in colon cancer.

国家自然科学基金资助项目（No. 413010173）