IGF2BP3 mediates the mRNA degradation of NF1 to promote triple‐negative breast cancer progression via an m6A‐dependent manner

BACKGROUND: N6‐methyladenosine (m6A) is an abundant reversible modification in eukaryotic mRNAs. Emerging evidences indicate that m6A modification plays a vital role in tumourigenesis. As a crucial reader of m6A, IGF2BP3 usually mediates the stabilisation of mRNAs via an m6A‐dependent manner. But the underlying mechanism of IGF2BP3 in the tumourigenesis of triple‐negative breast cancer (TNBC) is unclear. METHODS: TCGA cohorts were analysed for IGF2BP3 expression and IGF2BP3 promoter methylation levels in different breast cancer subtypes. Colony formation, flow cytometry assays and subcutaneous xenograft were performed to identify the phenotype of IGF2BP3 in TNBC. RNA/RNA immunoprecipitation (RIP)/methylated RNA immunoprecipitation (MeRIP) sequencing and luciferase assays were used to certify the target of IGF2BP3 in TNBC cells. RESULTS: IGF2BP3 was highly expressed in TNBC cell lines and tissues. TET3‐mediated IGF2BP3 promoter hypomethylation led to the upregulation of IGF2BP3. Knocking down IGF2BP3 markedly reduced the proliferation of TNBC in vitro and in vivo. Intersection co‐assays revealed that IGF2BP3 decreased neurofibromin 1 (NF1) stabilisation via an m6A‐dependent manner. NF1 knockdown could rescue the phenotypes of IGF2BP3 knockdown cells partially. CONCLUSION: TET3‐mediated IGF2BP3 accelerated the proliferation of TNBC by destabilising NF1 mRNA via an m6A‐dependent manner. This suggests that IGF2BP3 could be a potential therapeutic target for TNBC.