Long non‐coding RNA FTH1P3 activates paclitaxel resistance in breast cancer through miR‐206/ABCB1

Emerging evidence has indicated the important function of long non‐coding RNAs (lncRNAs) in tumour chemotherapy resistance. However, the underlying mechanism is still ambiguous. In this study, we investigate the physiopathologic role of lncRNA ferritin heavy chain 1 pseudogene 3 (FTH1P3) on the paclitaxel (PTX) resistance in breast cancer. Results showed that lncRNA FTH1P3 was up‐regulated in paclitaxel‐resistant breast cancer tissue and cells (MCF‐7/PTX and MDA‐MB‐231/PTX cells) compared with paclitaxel‐sensitive tissue and parental cell lines (MCF‐7, MDA‐MB‐231). Gain‐ and loss‐of‐function experiments revealed that FTH1P3 silencing decreased the 50% inhibitory concentration (IC50) value of paclitaxel and induced cell cycle arrest at G2/M phase, while FTH1P3‐enhanced expression exerted the opposite effects. In vivo, xenograft mice assay showed that FTH1P3 silencing suppressed the tumour growth of paclitaxel‐resistant breast cancer cells and ABCB1 protein expression. Bioinformatics tools and luciferase reporter assay validated that FTH1P3 promoted ABCB1 protein expression through targeting miR‐206, acting as a miRNA “sponge.” In summary, our results reveal the potential regulatory mechanism of FTH1P3 on breast cancer paclitaxel resistance through miR‐206/ABCB1, providing a novel insight for the breast cancer chemoresistance.