Long non-coding RNAs (lncRNAs) play a vital regulatory role in many human cancers. However, their underlying effect and molecular mechanism in chemoresistance need to be fully researched. This study found that lncRNA CYTOR expression was significantly up-regulated in colon carcinoma tissue and cells. Silencing lncRNA CYTOR in vitro facilitated L-OHP sensitivity of colon carcinoma cells and restrained epithelial-mesenchymal transition (EMT). Furthermore, lncRNA CYTOR could inhibit miR-378a-5p expression, while suppressing miR-378a-5p could attenuate the inhibition of lncRNA CYTOR silencing on L-OHP resistance and EMT. The downstream target mRNA of miR-378a-5p was further explored, and it was discovered that miR-378a-5p restrained SERPINE1 expression. Rescue assay indicated that overexpressing miR-378a-5p or silencing SERPINE1 expression counteracted the promotion of lncRNA CYTOR overexpression on L-OHP resistance and EMT of colon carcinoma cells. In vivo experiment exhibited that silencing lncRNA CYTOR repressed colon carcinoma growth, while miR-378a-5p inhibition diminished the suppression of silencing lncRNA CYTOR on colon carcinoma. These results testified that lncRNA CYTOR enhanced L-OHP drug resistance and induced EMT in colon carcinoma. It was also suggested that lncRNA CYTOR/miR-378a-5p/SERPINE1 axis was a regulatory pathway of L-OHP resistance in colon carcinoma. They could be potential therapeutic targets and prognostic biomarkers.Abbreviations: ATG: autophagy related; EPG: ectopic PGL granules; GFP: green fluorescent protein; LGG-1: LC3, GABARAP and GATE-16 family; LPLA-2: lysosomal phospholipase A2; PGL: P granule abnormality protein; PLA2: phospholipase A2; SD: standard deviation; SEPA-1: suppressor of ectopic P granules in autophagy mutant; SQST-1: sequestosome related.
Keywords: L-OHP; SERPINE1; colon carcinoma; drug resistance; epithelial–mesenchymal transition; lncRNA CYTOR; miR-378a-5p.