Hypoxia induces chemoresistance of esophageal cancer cells to cisplatin through regulating the lncRNA-EMS/miR-758-3p/WTAP axis
Zijiang Zhu, Yao Pang, Gang Jin, Hongyi Zhang, Wenhao Wang, Jiawei Liu, Guangxin Tuo, Peng Wu, Yi Yang, Zequan Wang, Kui Wang
Abstract
Hypoxia contributes significantly to the development of chemoresistance of many malignancies including esophageal cancer (EC). Accumulating studies have indicated that long non-coding RNAs play important roles in chemotherapy resistance. Here, we identified a novel lncRNA-EMS/miR-758-3p/WTAP axis that was involved in hypoxia-mediated chemoresistance to cisplatin in human EC. Hypoxia induced the expressions of lncRNA EMS and WTAP, and reduced the expression of miR-758-3p in EC cell line ECA-109. In addition, the expressions of EMS and WTAP were required for the hypoxia-induced drug resistance to cisplatin in EC cells, while overexpression of miR-758-3p reversed such chemoresistance. The targeting relationships between EMS and miR-758-3p, as well as miR-758-3p and WTAP, were verified by luciferase-based reporter assays and multiple quantitative assays after gene overexpression/knockdown. Moreover, we found significant correlations between tumor expressions of these molecules. Notably, higher levels of EMS/WTAP, or lower levels of miR-758-3p in tumors predicted worse survivals of EC patients. Furthermore, in a xenograft mouse model, targeted knockdown of EMS and WTAP in ECA-109 cells markedly attenuated the resistance of tumors to cisplatin treatments. Our study uncovers a critical lncRNA-EMS/miR-758-3p/WTAP axis in regulating hypoxia-mediated drug resistance to cisplatin in EC.