Long noncoding RNA ASH1L-AS1 promotes glycolysis and cisplatin resistance in ovarian cancer cells via its regulation on EZH2-mediated CNRIP1 methylation

Abstract

Background As one of the commonest female malignant tumors, ovarian cancer (OC) is regarded as a serious public burden in the world. In this work, we hypothesized that long noncoding RNA ASH1L-AS1 could regulate the glycolytic pathway to affect the sensitivity of OC cells to cisplatin. The present study aims at proving this hypothesis and the possible mechanism. Methods The differential expression of the genes in GSE38666 dataset was analyzed, and the results were verified by RT-qPCR method in the OC tumor tissues and cell lines. Then, the expressions of ASH1L-AS1 and CNRIP1 were altered in A2780 OC cell lines by plasmid transfection, followed by 10 µmol/mL of cisplatin treatment. After the cell treatment, the extracellular acidification rate (ECAR) and lactate production were quantified, while the cell functions of proliferation, colony formation, migration, and apoptosis were evaluated. Also, the expression levels of the key genes related to glycolytic pathway (GAPDH, ALDOA, and PKM2) were identified. Finally, the in vitro results were verified in vivo by subcutaneous tumor formation experiment. Results ASH1L-AS1 was verified to be highly-expressed in OC. LncMAP database prediction indicated that ASH1L-AS1 may be involved in the regulation of CNRIP1. Moreover, ASH1L-AS1 overexpression or EZH2 overexpression was found to promote the glycolysis and cisplatin resistance of OC cells, which also increased the cancerous cell growth in vitro and tumor growth in vivo. Also, the relationship analysis results revealed that ASH1L-AS1 could increase the methylation of CNRIP1 promoter region through the recruitment of EZH2. Conclusions ASH1L-AS1 may increase the promoter methylation of CNRIP1 by recruiting EZH2, which promotes the glycolysis and chemoresistance to cisplatin of OC cells, highlighting a novel therapy target for OC.