Tetrathiomolybdate as an old drug in a new use: As a chemotherapeutic sensitizer for non-small cell lung cancer

Cisplatin-based chemotherapy is the standard treatment for non-small cell lung cancer (NSCLC). However, cisplatin resistance is a major obstacle to successful therapeutic efficacy. Novel therapeutic strategies are urgently needed to reverse chemotherapy resistance and improve prognosis. In the present study, we aimed to investigate whether copper chelator Tetrathiomolybdate (TM) can enhance the anticancer effect of cisplatin, and elucidate the underlying mechanisms. Cell viability, wounding healing, and colony formation assays were performed on H1299 and A549 cells. The combination indices (CI) were determined by the Chou-Talalay method. Flow cytometry was used to detect cell apoptosis and ROS generation. GSH levels were measured in a microplate reader. RNA-seq and bioinformatics analyses were used to analyze the differentially expressed genes (DEGs) and enriched biology processes. The concentrations of Pt and Cu were determined by ICP-MS. Animal xenograft tumor model was established to evaluate the synergistic anticancer effect of TM and cisplatin. Combination treatment with TM and cisplatin decreased cell viability and migration of H1299 and A549 cells compared with cisplatin alone. Mechanistically, combination treatment could significantly increase ROS and reduce GSH content, leading to a notable increase in DNA-bound Pt and cell apoptosis. Moreover, in animal xenograft tumor model, TM enhanced cisplatin-elicited antitumor effect, but did not increase cisplatin-induced side effects. Our study suggests that TM may be a promising chemotherapeutic sensitizer for non-small cell lung cancer.