Effect mono-ADP-ribosylation on lipid metabolism of colorectal cancer by regulating IGFBP1 methylation

Abstract In the global health community, colon cancer (CRC) is a major concern, with a high rate of incidence. Epigenetics is recognized as one of the causes of CRC development and progression. Mono-ADP-ribosylation (MARylation) is a type of epigenetics, although the modification level and the target protein in CRC remain unclear. We previously reported that the MARylation of arginine-117 of histone 3 (H3R117) promotes the proliferation, upregulates methylation of tumor suppressor gene, and is tightly associated with the metabolic processes in LoVo cells. Lipid metabolism disorder is involved in the development of CRC at the early stage. Our study revealed that MARylation of H3R117 of the LoVo cells modulated lipid metabolism, increased cholesterol synthesis, promoted lipid raft (LR) protein IGF-1R distribution, and inhibited cell apoptosis through IGFBP1. In addition, bioinformatics analyses revealed that the IGFBP1 promoter was hypermethylated in CRC when compared to that in normal tissues. Moreover, H3R117 MARylation upregulated the methylation of IGFBP1 promoter through histone H3 citrullination (H3cit) by increasing the H3K9me2, heterochromatin protein1 (HP1), and DNA methyltransferase 1 (DNMT1) enrichment of IGFBP1 promoter. Accordingly, IGFBP1 may function as a tumor suppressor gene, while H3R117 MARylation may promote CRC development. Our study findings enrich the available data on epigenetics of CRC and provide a new idea and experimental basis for H3R117 MARylation as a target in CRC treatment.