GATA1-induced upregulation of LINC01503 promotes carboplatin resistance in ovarian carcinoma by upregulating PD-L1 via sponging miR-766-5p

BACKGROUND: Ovarian Carcinoma (OCa) is a high-mortality malignancy derived from female reproductive system. Increasing evidence has identified long non-coding RNAs (lncRNAs) as important regulators in OCa chemoresistance. In this study, we intended to explore the role of LINC01503 in OCa resistance to carboplatin (CBP). METHODS: Gene expression was measured by reverse transcription-quantitative PCR (RT-qPCR) in OCa cells. Western blot was adopted to detect protein levels of GATA1, PD-L1, E-cadherin, N-cadherin, Vimentin, Bcl-2, Bax, cleaved caspase-3. To assess the effects of LINC01503 on the resistance of OCa cells to CBP, Cell Counting Kit-8 (CCK-8), colony formation, Transwell, and flow cytometry experiments were performed to evaluate half-maximal inhibitory concentration (IC(50)), cell viability, migrative and invasive ability, as well as cell apoptosis. Dual-luciferase reporter assay was employed to assess the associations between the genes. RESULTS: LINC01503 was upregulated in CBP-resistant OCa cells. LINC01503 knockdown reduced CBP resistance in OCa cells. Besides, GATA-binding protein 1 (GATA1) activated LINC01503 transcription in CBP-resistant OCa cells. MiR-766-5p was lowly expressed in CBP-resistant cells and confirmed as a target for LINC01503. In addition, miR-766-5p overexpression increased CBP sensitivity in OCa cells. PD-L1 was verified as the target of miR-766-5p. Besides, LINC01503 upregulated PD-L1 level by regulating miR-766-5p. Furthermore, rescue experiments showed that PD-L1 overexpression abrogated the inhibited impacts of blocking LINC01503 on CBP resistance in OCa cells. CONCLUSION: GATA1-induced LINC01503 expedited CBP resistance in OCa cells via the miR-766-5p/PD-L1 axis, providing a new target for improving the efficacy of OCa chemotherapy. GRAPHICAL ABSTRACT: [Image: see text]