DNMT3a通过STAT3及RAD51影响胰腺癌细胞对奥沙利铂敏感性的研究

DNMT3a modulates chemosensitivity to oxaliplatin via STAT3 and RAD51 in pancreatic cancer cells

目的:检测DNMT3a在胰腺癌细胞中的表达及对奥沙利铂(oxaliplatin,OXA)敏感性的影响,探讨DNMT3a对胰腺癌细胞奥沙利铂敏感性影响的机制。方法:MTT法检测奥沙利铂对人胰腺癌Panc-1细胞的增殖影响,及下调DNMT3a对Panc-1细胞奥沙利铂敏感性的影响。Western blot检测siD NMT3a对DNMT3a蛋白表达的影响,检测奥沙利铂及下调DNMT3a对γ-H2AX、RAD51、p-STAT3和STAT3蛋白表达的影响。流式细胞仪检测奥沙利铂及联合下调DNMT3a对Panc-1细胞凋亡的影响。结果:奥沙利铂能够以浓度依赖方式抑制胰腺癌Panc-1细胞的增殖。奥沙利铂能够引起DNA损伤、γ-H2AX上调及RAD51增高,同时引起STAT3通路的一过性活化。下调DNMT3a表达能够明显增加Panc-1细胞对奥沙利铂的敏感性,抑制STAT3一过性活化,并抑制RAD51表达,促进DNA损伤,进而增加奥沙利铂诱导Panc-1细胞的凋亡。结论:下调DNMT3a表达能够通过抑制STAT3活化及增加DNA损伤增加胰腺癌细胞对奥沙利铂的敏感性,DNMT3a有望成为胰腺癌新的治疗靶点。

Objective：To detect the expression of DNMT3a in pancreatic cancer cells and its effect on the chemosensitivity to oxaliplatin （OXA），and to explore the mechanism of DNMT3a on the chemosensitivity of pancreatic cancer cells to OXA.Methods：MTT assay was used to detect the effect of OXA on the proliferation of Panc-1 cells，and the effect of down-regulation of DNMT3a on the inhibition of proliferation in Panc-1 cells induced by OXA.Western blot detected the expression of DNMT3a protein in Panc-1 cells which were transfected by siDNMT3a，and the expression of γ-H2AX，RAD51，p-STAT3 and STAT3 proteins.The flow cytometry was used to detecte apoptosis in Panc-1 cells after treatment of OXA and down-regulation of DNMT3a.Results：The treatment of OXA induced proliferation inhibition，enhanced DNA damage and elevated the expression of p-STAT3 and RAD51 in Panc-1 cells.Down-regulation of DNMT3a significantly increased the chemosensitivity of Panc-1 cells to OXA，inhibited STAT3 transient activation，inhibited RAD51 expression，promoted DNA damage，and further increased OXA induced apoptosis of Panc-1 cells.Conclusion：Down-regulation of DNMT3a increased the chemosensitivity of pancreatic cancer cells to OXA by inhibiting STAT3 activation and increasing DNA damage.DNMT3a is expected to be a new therapeutic target for pancreatic cancer.