Circ_0039569 contributes to the paclitaxel resistance of endometrial cancer via targeting miR-1271-5p/PHF6 pathway

Circular RNA (circRNA) has been confirmed to be involved in the chemoresistance process of cancers. However, whether circ_0039569 mediates the chemoresistance of endometrial cancer (EC) remains unclear. Quantitative real-time PCR was performed to analyze circ_0039569, microRNA (miR)-1271-5p and PHD finger protein 6 (PHF6) expression. Cell counting kit-8 assay was used to assess the paclitaxel (PTX) resistance of cells. Cell proliferation, apoptosis and invasion were determined using EdU assay, colony formation assay, flow cytometry and transwell assay. Protein expression was examined by western blot analysis. RNA interaction was verified by dual-luciferase reporter assay and RNA pull-down assay. Xenograft tumor models were constructed to explore the effect of circ_0039569 knockdown on the PTX sensitivity of EC tumors. Circ_0039569 was upregulated in PTX-resistant EC tissues and cells. Knockdown of circ_0039569 enhanced the PTX sensitivity of EC cells by inhibiting cell growth and invasion. MiR-1271-5p could be sponged by circ_0039569, and its inhibitor abolished the regulation of circ_0039569 knockdown on the PTX sensitivity of EC cells. PHF6 was targeted by miR-1271-5p, and its overexpression eliminated the promotion effect of miR-1271-5p on the PTX sensitivity of EC cells. Also, interference of circ_0036569 enhanced the PTX sensitivity of EC tumors by regulating the miR-1271-5p/PHF6 pathway. Collectively, circ_0039569 might contribute to the PTX resistance of EC through the regulation of the miR-1271-5p/PHF6 axis.