Tumor suppressive function of IGF2BP1 in gastric cancer through decreasing MYC

Gastric cancer is one of the most common causes of cancer-related death worldwide. The N6-methyladenosine (m6A) reader IGF2BP1 (insulin-like growth factor-2 mRNA binding protein 1) has been reported to promote cancer progression by stabilizing oncogenic mRNAs through its m6A-binding activity in some tumors. However, the role of IGF2BP1 in gastric carcinogenesis remains unclear. In this study, we find that IGF2BP1 is significantly downregulated in tumor tissues from patients with gastric cancer. Lower expression of IGF2BP1 is associated with poor prognosis. IGF2BP1 suppresses gastric cancer cell proliferation in an m6A-dependent manner. Additionally, IGF2BP1 is able to significantly attenuate tumor growth of gastric cancer cells. Further m6A sequencing and m6A-RIP (RNA immunoprecipitation) assays show that MYC (c-myc proto-oncogene) mRNA is a target transcript of IGF2BP1 in gastric cancer cells. IGF2BP1 inhibits gastric cancer cell proliferation by reducing the mRNA and protein expression of MYC. Mechanistically, IGF2BP1 promotes the degradation of MYC mRNA and inhibits its translation efficiency. Taken together, these data suggest that IGF2BP1 plays a tumor-suppressive role in gastric carcinogenesis by downregulating MYC in an m6A-dependent manner, thereby making the IGF2BP1-MYC axis a potential target for gastric cancer treatment. Overall design: To explore the potential target transcript mediating the role of IGF2BP1 in gastric cancer, we performed m6A-RIP seq and RNA-seq in IGF2BP1-depleted MKN45 cells.