EGR2-mediated regulation of m6A reader IGF2BP proteins drive RCC tumorigenesis and metastasis via enhancing S1PR3 mRNA stabilization

Abstract

Emerging discoveries of dynamic and reversible N6-methyladenosine (m6A) modification on RNA in mammals have revealed the key roles of the modification in human tumorigenesis. As known m6A readers, insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs) are upregulated in most cancers and mediates the enhancement of m6A-modified mRNAs stability. However, the mechanisms of IGF2BPs in renal cell cancer (RCC) still remain unclear. Bioinformatic analysis and RT-qPCR were performed to evaluate the expression of IGF2BPs and m6A writer Wilms tumor 1-associating protein (WTAP) in RCC samples and its correlation with patient prognosis. In vitro, in vivo biological assays were performed to investigate the functions of IGF2BPs and WTAP in RCC. Chromatin immunoprecipitation-qPCR (ChIP-qPCR) combined with bioinformatics analysis and following western blot assay, dual-luciferase reporter assays were performed to validate the regulatory relationships between transcription factor (TF) early growth response 2 (EGR2) and potential target genes IGF2BPs. RNA sequencing (RNA-seq), methylated RNA immunoprecipitation-qPCR (MERIP-qPCR), RIP-qPCR, m6A dot blot, and dual-luciferase reporter assays combined with bioinformatics analysis were employed to screen and validate the direct targets of IGF2BPs and WTAP. Here, we showed that early growth response 2 (EGR2) transcription factor could increase IGF2BPs expression in RCC. IGF2BPs in turn regulated sphingosine-1-phosphate receptor 3 (S1PR3) expression in an m6A-dependent manner by enhancing the stability of S1PR3 mRNA. They also promoted kidney tumorigenesis via PI3K/AKT pathway. Furthermore, IGF2BPs and WTAP upregulation predicted poor overall survival in RCC. Our studies showed that the EGR2/IGF2BPs regulatory axis and m6A-dependent regulation of S1PR3-driven RCC tumorigenesis, which enrich the m6A-modulated regulatory network in renal cell cancer. Together, our findings provide new evidence for the role of N6-methyladenosine modification in RCC.

The role of Insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs) as m6A readers in cancer

“…IGF2BPs promote the stability and storage of c-MYC, and the oncogenic role of IGF2BPs depends on their function as m 6 A readers 11 . In renal cell cancer, transcription factor early growth response 2 (EGR2) increases the expressions of IGF2BPs, and IGF2BPs enhance the stability of sphingosine-1-phosphate receptor 3 (S1PR3) mRNA in m 6 A-dependent manner, and S1PR3 drives tumorigenesis and metastasis 190 . In acute myeloid leukemia (AML), RNA-binding protein YBX1 is required for survival of AML, and mechanistically, YBX1 can cooperate with IGF2BP1 and IGF2BP3 to increase the stability of c-MYC and BCL2 mRNA in an m 6 A dependent manner 191 .…”

METTL14-mediated N6-methyladenosine modification of ITGB4 mRNA inhibits metastasis of clear cell renal cell carcinoma

“…It’s acknowledged that the integrin family can be one of the regulators of the PI3K/AKT pathway [ 36 ], one of the most important signals that has been reported to be associated with m6A modification in cancers by recent articles [ 37 , 38 ]. In our study, stably suppressing ITGB4’s expression not only could weaken the phosphorylation of the PI3K and AKT proteins but also could restore it from being upregulated by METTL14 knockdown (Fig.…”

FTO promotes clear cell renal cell carcinoma progression via upregulation of PDK1 through an m6A dependent pathway

“…From January to October 2013, we obtained 24 paired specimens of tumor and adjacent normal tissues from RCC patients treated with radical nephrectomy in our hospital [ 56 ]. Written informed consents of patients were acquired.…”