Inducible HSP70 antagonizes cisplatin-induced cell apoptosis through inhibition of the MAPK signaling pathway in HGC-27 cells

Inducible heat shock protein 70 (HSP70; also known as HSPA1 or HSP72) is implicated in cancer. As a stress-inducible heat shock protein, HSP70 is highly expressed in a variety of cancers and correlates with metastasis, chemotherapy resistance and tumor prognosis. The present study demonstrated that suppression of HSP70 through the specific inhibitor pifithrin-mu or by HSP70 knockdown enhanced cisplatin-induced apoptosis in HGC-27 gastric cancer cells. By contrast, upregulation of HSP70 through transfection of a HSP70 overexpressing plasmid decreased cisplatin-induced HGC-27 cell apoptosis. In exploring the underlying molecular mechanisms, the present results revealed that HSP70 antagonized cisplatin-induced HGC-27 cell apoptosis by regulating the mitogen-activated protein kinase (MAPK) signaling pathway. In addition, suppressing the MAPK pathway enhanced cisplatin-induced HGC-27 cell apoptosis. Collectively, the present findings suggest that inhibition of HSP70 expression enhanced the sensitivity of HGC-27 cells to cisplatin via the MAPK signaling pathway, and that HSP70 may serve as a potential therapeutic target in gastric cancer.