ALKBH5 suppresses malignancy of hepatocellular carcinoma via m6A-guided epigenetic inhibition of LYPD1

Abstract

Background: N6-methyladenosine (m 6 A) modification is an emerging layer of epigenetic regulation which is widely implicated in the tumorigenicity of hepatocellular carcinoma (HCC), offering a novel perspective for investigating molecular pathogenesis of this disease. The role of AlkB homolog 5 (ALKBH5), one of the m 6 A demethylases, has not been fully explored in HCC. Here we clarify the biological profile and potential mechanisms of ALKBH5 in HCC. Methods: Expression of ALKBH5 and its correlation with clinicopathological characteristics of HCC were evaluated using tissue microarrays and online datasets. And biological effects of ALKBH5 in HCC were determined in vitro and in vivo. Subsequently, methylated RNA immunoprecipitation sequencing (MeRIP-seq) combined with RNA sequencing (RNA-seq), and following m 6 A dot blot, MeRIP-qPCR, RIP-qPCR or dual luciferase reporter assays were employed to screen and validate the candidate targets of ALKBH5. Results: We demonstrated that ALKBH5 was down-regulated in HCC, and decreased ALKBH5 expression was an independent prognostic factor of worse survival in HCC patients. Functionally, ALKBH5 suppressed the proliferation and invasion capabilities of HCC cells in vitro and in vivo. Mechanistically, ALKBH5-mediated m 6 A demethylation led to a post-transcriptional inhibition of LY6/PLAUR Domain Containing 1 (LYPD1), which could be recognized and stabilized by the m 6 A effector IGF2BP1. In addition, we identified that LYPD1 induced oncogenic behaviors of tumors in contrast to ALKBH5. Dysregulation of ALKBH5/LYPD1 axis impelled the progression of HCC. Conclusion: Our study reveals that ALKBH5, characterized as a tumor suppressor, attenuates the expression of LYPD1 via an m 6 A-dependent manner in HCC cells. Our findings enrich the landscape of m 6 A-modulated tumor malignancy, and provide new insights into potential biomarkers and therapeutic targets of HCC treatment.

m6A regulator-based methylation modification patterns characterized by distinct tumor microenvironment immune profiles in colon cancer

“…Subsequent correlation analysis also revealed that the two m 6 A-writers were inversely associated with immune cell infiltration. Inversely, the m 6 A RNA demethylase ALKBH5 exhibited an obvious enhancement in T lymphocyte infiltration and significant up-regulation in normal samples, indicating that the multiple types of post-transcriptional regulation underlay anti-tumor effects 76 , 77 . Together, these results suggest a diverse heterogeneity of m 6 A modification, demonstrating the importance of a comprehensive assessment of the m 6 A modification patterns and enhancing our understanding of epigenetic regulation on diverse physiological processes.…”

The m6A RNA Demethylase ALKBH5 Promotes Radioresistance and Invasion Capability of Glioma Stem Cells

“…In breast, lung, and gastric carcinomas, the overexpression of ALKBH5 or FTO have been shown to promote cell invasion [ 18 , 19 , 20 , 21 , 22 ]. On the contrary, m6A RNA methylation could facilitate cell migration in other cancers, including, prostate, pancreas, colon, or hepatic cancers [ 23 , 24 , 25 , 26 ].…”

ALKBH5 Gene Polymorphisms and Hepatoblastoma Susceptibility in Chinese Children

“…A lower ALKBH5 level was detected in hepatocellular carcinoma (HCC), indicating its prognostic factor of worse survival in HCC patients. Mechanistically, ALKBH5 acts as a tumor suppressor by inhibiting LY6/PLAUR Domain Containing 1 (LYPD1) via a m6A-dependent manner in HCC cells [ 36 ]. ALKBH5 also acts as a tumor suppressor in non-small cell lung cancer (NSCLC) [ 37 ].…”