Inhibition of LDHB triggers DNA damage and increases cisplatin sensitivity in pleural mesothelioma.

Pleural mesothelioma (PM) is an aggressive, asbestos-linked cancer with limited treatment options and a poor prognosis. Lactate dehydrogenase B (LDHB) converts lactate to pyruvate, and its silencing reduces mitochondrial metabolism, particularly nucleotide synthesis. However, whether and a role of LDHB in PM is unclear. This study aimed to investigate the effects of silencing LDHB in PM cells and their response to chemotherapy. LDHB was silenced using siRNA transfection and inducible shRNA constructs. Proliferation, colony formation, and cell viability were assessed, while DNA damage was analyzed through ɣH2AX levels. Compared to normal mesothelial cells, LDHB was highly expressed in PM cell lines. LDHB inhibition significantly reduced proliferation, cell viability, and colony formation, indicating its crucial role in PM cells. Additionally, LDHB silencing significantly increased nuclear DNA damage accumulation as indicated by elevated ɣH2AX levels, which was reversed by nucleotide supplementation. In vivo, LDHB inhibition reduced tumor growth and enhanced cisplatin's therapeutic efficacy. LDHB silencing increased ɣH2AX levels, which were further elevated with cisplatin treatment. Our results highlight LDHB as a novel therapeutic target in PM, where its inhibition induces DNA damage and improves the efficacy of cisplatin therapy.