m6A modification suppresses ocular melanoma through modulating HINT2 mRNA translation

Abstract

Background: Dynamic N 6-methyladenosine (m 6 A) RNA modification generated and erased by N 6methyltransferases and demethylases regulates gene expression, alternative splicing and cell fate. Ocular melanoma, comprising uveal melanoma (UM) and conjunctival melanoma (CM), is the most common primary eye tumor in adults and the 2nd most common melanoma. However, the functional role of m 6 A modification in ocular melanoma remains unclear. Methods: m 6 A assays and survival analysis were used to explore decreased global m 6 A levels, indicating a late stage of ocular melanoma and a poor prognosis. Multiomic analysis of miCLIP-seq, RNA-seq and Labelfree MS data revealed that m 6 A RNA modification posttranscriptionally promoted HINT2 expression. RNA immunoprecipitation (RIP)-qPCR and dual luciferase assays revealed that HINT2 mRNA specifically interacted with YTHDF1. Furthermore, polysome profiling analysis indicated a greater amount of HINT2 mRNA in the translation pool in ocular melanoma cells with higher m 6 A methylation. Results: Here, we show that RNA methylation significantly inhibits the progression of UM and CM. Ocular melanoma samples showed decreased m 6 A levels, indicating a poor prognosis. Changes in global m 6 A modification were highly associated with tumor progression in vitro and in vivo. Mechanistically, YTHDF1 promoted the translation of methylated HINT2 mRNA, a tumor suppressor in ocular melanoma. Conclusions: Our work uncovers a critical function for m 6 A methylation in ocular melanoma and provides additional insight into the understanding of m 6 A modification.

m6A-binding proteins: the emerging crucial performers in epigenetics

“…In melanoma, depletion of YTHDF2 accelerated cell proliferation and migration by strikingly upregulating the mRNA levels of three key intrinsic pro-tumorigenic factors, including PD-1 (PDCD1), CXCR4, and SOX10, which was dependent on a reduced m 6 A-mediated mRNA decay [64]. Furthermore, YTHDF1 promoted the translation of tumor suppressor HINT2 mRNA which was methylated by m 6 A, thus playing a repressive role in ocular melanoma [65].…”

“…Downregulating the mRNA and protein levels of three key intrinsic pro-tumorigenic factors, including PD-1 (PDCD1), CXCR4 and SOX10 [64] YTHDF1 HINT2 Promoting the translation of HINT2 mRNA [65] Breast cancer YTHDF2 BNIP3 Facilitating the degradation of BNIP3 mRNA [66] Pancreatic cancer IGF2BP2 DANCR Enhancing the DANCR expression [67] Acute myeloid leukemia…”

N6-Methyladenosine: A Novel RNA Imprint in Human Cancer

“…On the other hand, in ocular melanoma, YTHDF1 promotes the translation of m 6 A-containing HINT2 mRNA, a tumor suppressor (65). Scientists reported decreased m 6 A levels in these tumor samples, which was significantly correlated with tumor progression both in vitro and in vivo.…”

Novel insight into the regulatory roles of diverse RNA modifications: Re-defining the bridge between transcription and translation

“…With the help of YTHDF1, the translation of methylated HINT2 mRNA, a tumour suppressor of ocular melanoma, was significantly accelerated, meaning m 6 A modification obviously inhibits the progression of ocular melanoma. Moreover, investigation of ocular melanoma samples indicated that decreased m 6 A levels were highly associated with poor prognosis [140].…”