Introduction and Objective: Cisplatin is an important chemotherapeutic agent against metastatic bladder cancer, but resistance often limits its usage. With the recent recognition of lipid metabolic alterations in bladder cancers, we studied the metabolic implications of cisplatin resistance using cisplatin-sensitive (T24S) and resistant (T24R) bladder cancer cells.
Methods: To test whether there should be differences in metabolism and metabolism-associated pathways between cisplatin-sensitive and resistant bladder cancer cells, we applied the live metabolomics approach that we recently developed to isogenic bladder cancer cell lines T24S (cisplatin sensitive) and T24R (cisplatin resistant). The metabolites generated from 13C-glucose tracer were monitored with 2D 1H-13C HSQC NMR in real time.
Results: Real-time live metabolomics revealed that T24R cells consume more glucose, leading to higher production of glucose-derived acetate and fatty acids. Along with the activation of general metabolic regulators, enzymes involved in acetate usage (ACSS2) and fatty acid synthesis (ACC) and a precursor for fatty acid synthesis (acetyl-CoA) were elevated in T24R cells. Consistently, metabolic analysis with 13C isotope revealed that T24R cells preferred glucose to acetate as the exogenous carbon source for the increased fatty acid synthesis, contrary to T24S cells. In addition, ACSS2, rather than the well-established ACLY, was the key enzyme that supplies acetyl-CoA in T24R cells through glucose-derived endogenous acetate. The relevance of ACSS2 in cisplatin resistance was further confirmed by the abrogation of resistance by an ACSS2 inhibitor and, finally, by the higher expression of ACSS2 in the patient tissues with cisplatin resistance.
Conclusions: Our results may help improve the treatment options for chemoresistant bladder cancer patients and provide possible vulnerability targets to overcome the resistance.
Citation Format: Jayoung Kim. Altered acetate metabolism in cisplatin resistant bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4355.