ALKBH5-mediated m6A modification of lincRNA LINC02551 enhances the stability of DDX24 to promote hepatocellular carcinoma growth and metastasis

Abstract As the most important RNA epigenetic regulation in eukaryotic cells, N6-metheyladenosine (m 6 A) modification has been demonstrated to play significant roles in cancer progression. However, this modification in long intergenic non-coding RNAs (lincRNAs) and the corresponding functions remain elusive. Here, we showed a lincRNA LINC02551 was downregulated by AlkB Homolog 5 (ALKBH5) overexpression in a m 6 A-dependent manner in hepatocellular carcinoma (HCC). Functionally, LINC02551 was required for the growth and metastasis of HCC. Mechanistically, LINC02551 , a bona fide m 6 A target of ALKBH5, acted as a molecular adaptor that blocked the combination between DDX24 and a E3 ligase TRIM27 to decrease the ubiquitination and subsequent degradation of DDX24, ultimately facilitating HCC growth and metastasis. Thus, ALKBH5-mediated LINC02551 m 6 A methylation was required for HCC growth and metastasis.