Dampening HOTAIR sensitizes the gastric cancer cells to oxaliplatin through miR‐195‐5p and ABCG2 pathway

Abstract Long non‐coding RNAs (lncRNA) have an extensive role in the progression and chemoresistance of gastric cancer (GC). Deeply study the regulatory role of lncRNAs could provide potential therapeutic targets. The aim of this study is to explore the regulatory role of HOTAIR in the progression and oxaliplatin resistance of GC. The expression of HOTAIR in GC and cell lines were detected by using qRT‐PCR. Cell proliferation and apoptosis were analysed by CCK‐8, EdU incorporation and flow cytometry. Luciferase reporter assay was used to identify the interaction between HOTAIR and ABCG2 (ATP‐binding cassette (ABC) superfamily G member 2, ABCG2) via miR‐195‐5p. The regulatory functions were verified by using molecular biology experiments. HOTAIR was significantly overexpressed in GC and associated with poor prognosis. Knock‐down of HOTAIR inhibited the GC cells proliferation and oxaliplatin resistance, while overexpression of HOTAIR showed opposite functions. Further studies found that HOTAIR acted as a competing endogenous RNA (ceRNA) to absorb miR‐195‐5p and elevated the expression of ABCG2, which leads to resistance of GC cells to oxaliplatin. Taken together, our findings demonstrated that HOTAIR regulates ABCG2 induced resistance of GC to oxaliplatin through miR‐195‐5p signalling and illustrate the great potential of developing new therapeutic targets for GC patients.