Oxamate, an LDHA Inhibitor, Inhibits Stemness, Including EMT and High DNA Repair Ability, Induces Senescence, and Exhibits Radiosensitizing Effects in Glioblastoma Cells

Abstract

Enhancement of glycolysis has been reported in tumor cells, and it is believed that this enhancement is important for maintaining the stemness of tumor cells and contributes to malignant phenotypes. Here, we investigated the effects of Oxamate, which inhibits glycolysis by blocking the conversion of pyruvate to lactate, on radiosensitivity and its molecular mechanisms in T98G glioblastoma cells. Oxamate significantly enhanced radiosensitivity by delaying DNA repair, as indicated by the persistence of γ-H2AX foci up to four days post-irradiation. Mechanistically, Oxamate suppressed the expression and phosphorylation of key DNA repair factors. Furthermore, Oxamate induced apoptosis and promoted cellular senescence, as evidenced by the accumulation of SA-β-gal and the upregulation of pS15-p53 and p21. In addition, Oxamate downregulated EGFR expression, reduced the levels of stem cell markers, and modulated epithelial–mesenchymal transition (EMT) markers, suggesting a potential suppression of EMT-related pathways. Together, these results demonstrate that Oxamate enhances radiosensitivity in glioblastoma cells through multiple mechanisms, including the inhibition of DNA repair, induction of apoptosis and senescence, and suppression of cancer stem cell properties and EMT. Our findings provide new insights into the potential use of Oxamate as a radiosensitizer and warrant further investigation of its clinical application in glioblastoma therapy.