SLC7A11 negatively associates with mismatch repair gene expression and endows glioblastoma cells sensitive to radiation under low glucose conditions

The cystine/glutamate antiporter xCT (SLC7A11) is frequently upregulated in many cancers, including glioblastoma (GBM). SLC7A11-mediated cystine taken up is reduced to cysteine, a precursor amino acid for glutathione synthesis and antioxidant cellular defense. However, little is known about the biological functions of SLC7A11 and its effect on therapeutic response in GBM. Here, we report that the expression of SLC7A11 is higher in GBM compared with normal brain tissue, but is negatively associated with tumor grades and positively impacts survival in the bioinformatic analysis of TCGA and CGGA database. Additionally, a negative association between SLC7A11 and mismatch repair (MMR) gene expression was identified by Pearson correlation analysis. In the GBM cells with glucose-limited culture conditions, overexpression of SLC7A11 significantly decreased MMR gene expression, including MLH1, MSH6, and EXO1. SLC7A11-overexpressed GBM cells demonstrated elevated double-strand break (DSB) levels and increased sensitivity to radiation treatment. Taken together, our work indicates that SLC7A11 might be a potential biomarker for predicting a better response to radiotherapy in GBM.