RBM15 Contributes to Bladder Carcinoma Progression via m6A-dependent Stabilization of IFI6 mRNA.

Abstract

Bladder carcinoma (BLCA) is a prevalent urological malignancy with limited therapeutic options. Interferon α inducible protein 6 (IFI6) is implicated in various cancers, but its role in BLCA remains unexplored. qRT-PCR and western blot were used for expression analysis. Functional assays (cell counting kit 8, 5-ethynyl-2'-deoxyuridine staining, flow cytometry, wound healing, transwell, and 2', 7'-dichlorodihydrofluorescein diacetate fluorescent probe) and xenograft mouse models were used to assess the effects of IFI6 and RNA binding motif protein 15 (RBM15) on BLCA. The N6-methyladenosine (m6A) modification sites on IFI6 were predicted by the sequence-based RNA adenosine methylation site predictor website and the combination of RBM15 was validated via RNA-binding proteins site prediction websites, methylated RNA immunoprecipitation, Actinomycin D, dual-luciferase reporter assay, and RNA binding protein immunoprecipitation assays. IFI6 was elevated in BLCA tissues and cells. IFI6 knockdown could inhibit proliferation, migration, and invasion, while enhancing apoptosis and oxidative stress of BLCA cells. Besides, silencing of IFI6 blocked BLCA tumor growth. RBM15, an m6A writer, directly bound IFI6 to stabilize its mRNA through m6A modification. Rescue experiments confirmed that IFI6 overexpression reversed RBM15 knockdown-mediated the suppression effect on BLCA cell proliferation and metastasis. Our study identifies that RBM15/IFI6 axis is a novel m6A-dependent pathway driving BLCA progression, offering a potential therapeutic target for BLCA.