Long non-coding RNA NEAT1 promotes bone metastasis of prostate cancer through N6-methyladenosine.

Background: N6-methyladenosine (m6A) is the most prevalent messenger RNA modification in mammalian cells. However, the disease relevant function of m6A on specific oncogenic long non-coding RNAs (ncRNAs) is not well understood.

Methods: We analyzed the m6A status using patients samples and bone metastatic PDXs. Through m6A high-throughput sequencing, we identified the m6A sites on NEAT1-1 in prostate bone metastatic PDXs. Mass spec assay showed interaction among NEAT1-1, CYCLINL1 and CDK19. RNA EMSA, RNA pull-down, mutagenesis, CLIP, western blot, ChIP and ChIRP assays were used to investigate the molecular mechanisms underlying the functions of m6A on NEAT1-1. Loss-of function and rescued experiments were executed to detect the biological roles of m6A on NEAT1-1 in the PDX cell phenotypes in vivo.

Results: In this study, we identified 4 credible m6A sites on long ncRNA NEAT1-1. High m6A level of NEAT1-1 was related to bone metastasis of prostate cancer and m6A level of NEAT1-1 was a powerful predictor of eventual death. Transcribed NEAT1-1 served as a bridge to facility the binding between CYCLINL1 and CDK19 and promoted the Pol II ser2 phosphorylation. Importantly, depletion of NEAT1-1or decreased m6A of NEAT1-1 impaired Pol II Ser-2p level in the promoter of RUNX2. Overexpression of NEAT1-1 induced cancer cell metastasis to lung and bone; xenograft growth and shortened the survival of mice, but NEAT1-1 with m6A site mutation failed to do these.

Conclusion: Collectively, the findings indicate that m6A on ncRNA NEAT1-1 takes critical role in regulating Pol II ser2 phosphorylation and may be novel specific target for bone metastasis cancer therapy and diagnosis. New complex CYCLINL1/CDK19/NEAT1-1 might provide new insight into the potential mechanism of the pathogenesis and development of bone metastatic prostate cancer.