RNA methylation at position N6 in adenosine (m6A) and its associated methyltransferase complex (MTC) are involved in tumorigenesis. We aimed to explore m6A biological function for long non-coding RNAs (lncRNAs) in prostate cancer (PCa) and its clinical significance. m6A and MTC levels in PCa cells were characterized by ELISA and western blot. Putative m6A-regulated lncRNAs were identified and validated by lncRNA profiler qPCR array and bioinformatics analysis, followed by m6A/RNA co-immunoprecipitation. Impact of m6A depletion on RNA stability was assessed by Actinomycin D assay. The association of m6A-levels with PCa prognosis was examined in clinical samples. Higher m6A-levels and VIRMA overexpression were detected in metastatic castration-resistant PCa (mCRPC) cells (p < 0.05). VIRMA knockdown in PC-3 cells significantly decreased m6A-levels (p = 0.0317), attenuated malignant phenotype and suppressed the expression of oncogenic lncRNAs CCAT1 and CCAT2 (p < 0.00001). VIRMA depletion and m6A reduction decreased the stability and abundance of CCAT1/2 transcripts. Higher expression of VIRMA, CCAT1, and CCAT2 as a group variable was an independent predictor of poor prognosis (HR = 9.083, CI95% 1.911–43.183, p = 0.006). VIRMA is a critical factor sustaining m6A-levels in PCa cells. VIRMA downregulation attenuates the aggressive phenotype of PCa by overall reduction of m6A-levels decreasing stability and abundance of oncogenic lncRNAs.

Epitranscriptome, Long non-coding RNAs, N6-Methyladenosine, Prostate cancer, VIRMA
dx.doi.org/10.3390/cancers12040771, hdl.handle.net/1765/126331
Department of Urology

Barros-Silva, D. (Daniela), Lobo, J. (João), Guimarães-Teixeira, C. (Catarina), Carneiro, I. (Isa), Oliveira, J. (Jorge), Martens-Uzunova, E.S, … Jerónimo, C. (Carmen). (2020). VIRMA-dependent N6-methyladenosine modifications regulate the expression of long non-coding RNAs CCAT1 and CCAT2 in prostate cancer. Cancers, 12(4). doi:10.3390/cancers12040771