HSPA6, a novel prognostic and therapeutic biomarker, associated with Ming classification in gastric cancer

OBJECTIVE: This study aimed to explore the clinical relevance of heat shock protein family A member 6 (HSPA6) in gastric cancer (GC) and its effect on GC cell proliferation. METHODS: HSPA6 mRNA and protein levels were analyzed by bioinformatics, RT‐qPCR, western blot and immunohistochemistry. HSPA6 was correlated with clinicopathological variables by the Chi‐square test. Kaplan–Meier survival analysis and the univariate and multivariate Cox models were used to assess the prognostic value of HSPA6. Nomogram was used to predict overall survival in patients with GC. Knockdown or over‐expression of HSPA6 in GC cell lines was constructed by lentiviral transduction. EdU and CCK‐8 assay were used to detect cell proliferation. In vivo mouse tumor models were performed to evaluate the effects of HSPA6 on GC growth. RESULTS: HSPA6 were significantly upregulated in the GC tissues compared to the normal stomach epithelium and were associated with Ming classification (p < 0.001) and tumor size (p = 0.002). Patients with high expression of HSPA6 showed worse survival compared to the low expression group. HSPA6 was identified to be an independent prognostic biomarker for GC. HSPA6 was functionally annotated with the cell cycle, G2M checkpoint and Hippo pathway. Knockdown of HSPA6 suppressed XGC‐1 cell proliferation both in vitro and in vivo. Overexpression of HSPA6 in AGS cells increased proliferation rates, increased the levels of cyclinB1 and YAP and decreased that of phosphorylated YAP. HSPA6 knockdown in the NUGC2 cells had the opposite effect. CONCLUSIONS: HSPA6 promotes GC proliferation by the Hippo pathway, as a novel prognostic biomarker and potential therapeutic target.