泮托拉唑通过抑制自噬提高人胃腺癌细胞对顺铂的敏感性

背景：肿瘤细胞对化疗药物不敏感／耐药是肿瘤治疗的主要障碍之一．应用高效低毒性化疗增敏剂可优化化疗方案，提高疗效。前期研究显示质子泵抑制剂泮托拉唑（PPZ）预处理可抑制空泡型质子泵V-H＋-ATP酶，逆转细胞内外pH梯度．提高人胃腺癌细胞的化疗敏感性。目的：探讨PPZ能否通过抑制自噬提高人胃腺癌细胞对顺铂（DDP）的敏感性及其可能机制。方法：以免疫荧光法和（或）蛋白质印迹法观察经PPZ或DDP处理或ATG7siRNA干扰，或先予PPZ预处理或ATG7siRNA干扰再予DDP处理的人胃腺癌细胞株SGC7901的自噬体以及自噬特异性标记物LC3、p62、自噬相关蛋白ATG7、自噬调节关键分子mTOR表达，以CCK-8实验检测各组SGC7901细胞增殖率的变化。结果：DDP能诱导SGC7901细胞自噬，PPZ能抑制SGC7901细胞自噬。PPZ预处理能增强DDP对SGC7901细胞的生长抑制作用．并上调mTOR蛋白表达．其作用与ATG7基因干扰一致。结论：PPZ预处理可通过抑制自噬提高人胃腺癌细胞对DDP的敏感性．其机制可能与激活mTOR有关。

Pantoprazole Augments Sensitivity of Human Gastric Adenocarcinoma Cells to Cisplatin by Inhibition of Autophagy

Background: Insensitivity or resistance of cancer cells to chemotherapy is becoming a major obstacle for successful cancer therapy.Use of high efficient and low toxic chemotherapy sensitizers may improve the effect of chemotherapy.Previous study indicated that pretreatment with proton pump inhibitor pantoprazole(PPZ) could inhibit vacuolar-H+-ATPase,reversing the internal and external pH gradient,and augmenting the sensitivity of human gastric adenocarcinoma cells to chemotherapy.Aims: To investigate whether PPZ can augment the sensitivity of human gastric adenocarcinoma cells to cisplatin(DDP) by inhibition of autophagy and to elucidate its possible mechanism.Methods: Immunofluorescence and/or Western blotting were used to assess the autophagosome and expressions of LC3 and p62(autophagy specific markers),ATG7(an autophagy-related protein) and mTOR(a key regulator of autophagy) in human gastric adenocarcinoma cell line SGC7901 treated with PPZ or DDP or interfered with ATG7 siRNA,or pretreated with PPZ or interfered with ATG7 siRNA followed by DDP treatment,respectively.Changes in cell proliferation rate of SGC7901 cells in different treatment groups were detected by CCK-8 assay.Results: DDP could induce autophagy and PPZ could inhibit autophagy in SGC7901 cells.Pretreatment with PPZ enhanced the growth inhibition effect of DDP on SGC7901 cells,and up-regulated mTOR protein expression.Efficiency of PPZ pretreatment was consistent with ATG7 gene interference.Conclusions: PPZ pretreatment can inhibit autophagy and augment the sensitivity of human gastric adenocarcinoma cells to DDP,the mechanism might be related to activation of mTOR.