Background: Doxorubicin (DOXO) is currently administered as the first-choice therapy for a variety of malignancies. Cancer cells exhibit enhanced glycolysis and lactate production. This metabolite affects gene expression and can play a role in chemoresistance.
Aim of this study: We investigated whether the enhanced lactate levels that characterize neoplastic tissues can modify the response of cancer cells to DOXO.
Methods: After exposing cancer cells to increased lactate levels, we examined whether this metabolite could interfere with the principal mechanisms responsible for the DOXO antineoplastic effect.
Results: Increased lactate levels did not affect DOXO-induced topoisomerase poisoning but offered protection against the oxidative damage caused by the drug. This protection was related to changes in gene expression caused by the combined action of DOXO and lactate. Oxidative damage significantly contributed to the heavy cardiotoxicity following DOXO treatment. In cultured cardiomyocytes, we confirmed that DOXO-induced DNA damage and oxidative stress can be significantly mitigated by exposing the cells to increased lactate levels.
Conclusions: In addition to contributing to elucidating the effects of the combined action of DOXO and lactate, our results suggest a possible method to reduce the heavy drug cardiotoxicity, a major side effect leading to therapy discontinuation.
Keywords: cancer cell metabolism; doxorubicin; lactate; oxidative stress.