Hypoxia‐Inducible Factor HIF1α Regulates the Expression of SLC7A1 to Mediate Erastin‐Induced Ferroptosis in Cervical Cancer Cells
ABSTRACT
Objective
This study aims to investigate the regulation of hypoxia‐inducible factor 1α (HIF1α) on cationic amino acid transporter 1 (SLC7A1) expression and its potential mechanism YTH N6‐methyladenosine RNA binding protein 1 (YTHDF1) in Erastin‐induced ferroptosis in human cervical cancer (CaCx) cells.
Methods
Human CaCx cell lines (HeLa and SiHa) were cultured in vitro under normoxic or hypoxic conditions and treated with Erastin (30 μM, a stimulator of ferroptosis) before cell transfection with small interfering RNAs against HIF1α, YTHDF1, or SLC7A1 (si‐HIF1α, si‐YTHDF1 or si‐SLC7A1). Cell viability and the levels of malondialdehyde (MDA), reactive oxygen species (ROS), glutathione (GSH), and Fe2+ were measured, followed by transmission electron microscopy for ferroptosis‐associated mitochondrial morphological changes in CaCx cells. The interaction of HIF1α in YTHDF1 was determined by JASPAR database and dual‐luciferase reporter assay. Chromatin immunoprecipitation (ChIP) was performed to determine the enrichment of HIF1α at YTHDF1 promoter. The N6‐methyladenosine (m6A) methylation level of SLC7A1 was detected using Methylated RNA Immunoprecipitation (MeRIP) assay. In vivo experiments were conducted on nude mice via injection of HeLa or SiHa cells.
Results
Erastin repressed cell growth and induced ferroptosis in CaCx cells, while hypoxia pretreatment partly reversed the Erastin‐induced cytotoxicity and ferroptosis in CaCx cells. Erastin caused low HIF1α levels in CaCx cells, while hypoxia pretreatment partially counteracted this downregulation. Knockdown of HIF1α and YTHDF1 downregulated SLC7A1 expression and promoted Erastin‐induced ferroptosis in hypoxic CaCx cells. Additionally, HIF1α regulated YTHDF1 expression, leading to increased m6A methylation and activation of SLC7A1. The in vivo xenograft model further validated that Erastin inhibited tumor growth in CaCx, while the antitumor effect of Erastin was partially reversed by HIF1α overexpression.
Conclusions
HIF1α regulates the expression of YTHDF1, thereby enhancing the m6A modification level of SLC7A1, promoting its expression, and ultimately inhibiting Erastin‐induced ferroptosis in CaCx cells.