Knockdown of m6A Reader IGF2BP3 Inhibited Hypoxia-Induced Cell Migration and Angiogenesis by Regulating Hypoxia Inducible Factor-1α in Stomach Cancer.

Libin Jiang,Lvyin Yan,Yixin He,Yingxia Li,Dapeng Wei,Hongtao Wen

doi:10.3389/fonc.2021.711207

Abstract

Hypoxia is a common feature of solid tumors including stomach cancer (SC) and is closely associated with cancer malignant progression. N6-methyladenosine (m6A), a common modification on RNA, is involved in the regulation of RNA fate and hypoxic responses in cancers. However, the interaction between m6A reader insulin-like growth factor-II mRNA-binding protein 3 (IGF2BP3) and SC hypoxic microenvironment is poorly defined. In the present study, expression levels of IGF2BP3 and hypoxia inducible factor-1α (HIF1A) were examined by bioinformatics analysis and RT-qPCR and western blot assays. Cell migratory ability was assessed through Transwell and wound healing assays. The angiogenic potential was evaluated by VEGF secretion, tube formation, and chick embryo chorioallantoic membrane (CAM) assays. The interaction between IGF2BP3 and HIF1A was explored using bioinformatics analysis and RIP and luciferase reporter assays. The results showed that IGF2BP3 and HIF1A were highly expressed in SC tissues and hypoxia-treated SC cells. IGF2BP3 knockdown inhibited hypoxia-induced cell migration and angiogenesis in SC. IGF2BP3 positively regulated HIF1A expression by directly binding to a specific m6A site in the coding region of HIF1A mRNA in SC cells. HIF1A overexpression abrogated the effects of IGF2BP3 knockdown on hypoxia-induced cell migration and angiogenesis in SC. In conclusion, IGF2BP3 knockdown inhibited hypoxia-induced cell migration and angiogenesis by down-regulating HIF1A in SC.

Highlights

Stomach cancer (SC) is the fifth commonest cancer and the third most deadly cancer globally [1, 2]
We demonstrated that the global m6A level in total RNA was markedly increased in stomach cancer (SC) tumor tissues (n=20) than that in adjacent normal tissues (n=20) (Figure 1A), suggesting that the alteration of RNA m6A modification level was closely linked with the tumorigenesis and progression of SC
Western blot assay showed that IGF2BP3 protein expression level was notably increased in 6 SC tumor tissues compared to matched adjacent normal tissues (Figure 1E)

Summary

Introduction

Stomach cancer (SC) is the fifth commonest cancer and the third most deadly cancer globally [1, 2]. Stomach adenocarcinoma (STAD), the most common SC type, is highly treatable when it is diagnosed at early stages [3, 4]. Many SC cases are diagnosed at advanced stages and the prognosis of SC patients with advanced disease is poor with a median survival of approximately 1 year [3,4,5]. Role of IGF2BP3 in SC cancers can be largely attributed to the metastasis of tumor cells, which involves multiple biological processes such as cell growth, migration, invasion, and angiogenesis [6]. Hypoxic tumor cells undergo multiple alterations at the molecular, cellular, and phenotypic levels (e.g. increased migration, invasion, and angiogenesis) that can help them to survive in primary and secondary sites or escape from the unfavorable tumor environment [8, 9]. It is imperative to investigate the pathogenesis of SC in a hypoxic microenvironment

Methods

Results

Conclusion