Jie Bao1, Yun Xu1, Qunying Wang1, Jinping Zhang1, Zhenjie Li1, Dongying Li1, Jiansheng Li2. 1. Department of Gastroenterology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, China. 2. Department of Gastroenterology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, China. Electronic address: jianshengli12@163.com.
Abstract
BACKGROUND: Chemoresistance remains a main clinical obstacle in the treatment of gastric cancer (GC). microRNAs have been revealed to participate in the regulation of drug resistance in a variety of cancers. However, little is known about the function and detailed molecular mechanism of miR-101 in GC chemoresistance. METHODS: The expressions of miR-101 and Annexin A2 (ANXA2) in GC tissues and cells were detected by qRT-PCR and western blot. The effects of miR-101 overexpression on P-glycoprotein (P-gp) at mRNA and protein levels, cell viability, and apoptosis in drug-resistant GC cells were examined by qRT-PCR, western blot, MTT and flow cytometry analysis, respectively. Luciferase reporter assay, RNA immunoprecipitation (RIP) and qRT-PCR were applied to confirm whether miR-101 could target ANXA2 and regulate its expression. Rescue experiment was performed to verify the mechanism by which miR-101 involved in chemoresistance. RESULTS: miR-101 was downregulated in GC tissues and drug-resistant GC cells. A negative correlation between miR-101 and ANXA2 expression was observed in GC tissues. Forced expression of miR-101 significantly reduced P-gp expression at mRNA and protein levels in drug-resistant GC cells. Overexpression of miR-101 enhanced sensitivity to cisplatin (DDP) or vincristine (VCR) via viability inhibition and apoptosis promotion. ANXA2 was identified as a direct target of miR-101 and miR-101 negatively regulated ANXA2 expression. Moreover, ectopic expression of ANXA2 reversed the effect of miR-101 on P-gp expression, cell viability and apoptosis. CONCLUSION: miR-101 alleviated chemoresistance of gastric cancer cells by targeting ANXA2. Therefore, targeting miR-101 may be a potential therapeutic approach for drug-resistant GC.
BACKGROUND: Chemoresistance remains a main clinical obstacle in the treatment of gastric cancer (GC). microRNAs have been revealed to participate in the regulation of drug resistance in a variety of cancers. However, little is known about the function and detailed molecular mechanism of miR-101 in GC chemoresistance. METHODS: The expressions of miR-101 and Annexin A2 (ANXA2) in GC tissues and cells were detected by qRT-PCR and western blot. The effects of miR-101 overexpression on P-glycoprotein (P-gp) at mRNA and protein levels, cell viability, and apoptosis in drug-resistant GC cells were examined by qRT-PCR, western blot, MTT and flow cytometry analysis, respectively. Luciferase reporter assay, RNA immunoprecipitation (RIP) and qRT-PCR were applied to confirm whether miR-101 could target ANXA2 and regulate its expression. Rescue experiment was performed to verify the mechanism by which miR-101 involved in chemoresistance. RESULTS:miR-101 was downregulated in GC tissues and drug-resistant GC cells. A negative correlation between miR-101 and ANXA2 expression was observed in GC tissues. Forced expression of miR-101 significantly reduced P-gp expression at mRNA and protein levels in drug-resistant GC cells. Overexpression of miR-101 enhanced sensitivity to cisplatin (DDP) or vincristine (VCR) via viability inhibition and apoptosis promotion. ANXA2 was identified as a direct target of miR-101 and miR-101 negatively regulated ANXA2 expression. Moreover, ectopic expression of ANXA2 reversed the effect of miR-101 on P-gp expression, cell viability and apoptosis. CONCLUSION:miR-101 alleviated chemoresistance of gastric cancer cells by targeting ANXA2. Therefore, targeting miR-101 may be a potential therapeutic approach for drug-resistant GC.