Carbonic Anhydrase as a Cardioprotective Target in Anthracycline-induced Cardiotoxicity - PROJECT SUMMARY Heart disease is a leading cause of mortality among cancer survivors, significantly impacting over 9% of the 16.9 million adult survivors in the United States. These survivors develop heart conditions post-treatment due to the cardiotoxic effects of chemotherapy agents like anthracyclines. Anthracyclines, such as doxorubicin, are potent chemotherapeutic agents used extensively in cancer treatments. They are administered in approximately 60% of breast cancer and 70% of childhood cancer cases. However, they cause acute cardiotoxicity in about 11% of patients, with detrimental cardiac effects persisting for up to 40 years in childhood cancer survivors. Current cardioprotective therapies, including dexrazoxane, have demonstrated limited long-term efficacy and raise concerns about potential interference with doxorubicin's antitumor effect. This highlights a significant gap in effective cardioprotective therapies due to an insufficient understanding of the molecular mechanisms underlying anthracycline-induced cardiotoxicity (AIC). Recent advancements in human induced pluripotent stem cell- derived cardiomyocytes (iCMs) offer unprecedented opportunities to model human cardiac diseases at an individual level, providing a novel avenue to explore the mechanisms of AIC. Leveraging the iCM model, combined with CRISPR interference/activation (CRISPRi/a) genetic screens, our preliminary studies have identified that inhibition of Carbonic Anhydrase XII (CA12) mitigates AIC in iCMs and in mice treated with doxorubicin. CA12 is involved in regulating intracellular pH and metabolism, potentially enhancing lactate production through glycolysis. Our findings suggest that doxorubicin upregulates glycolysis in iCMs via CA12 activation, leading to increased lactate production and subsequent histone lactylation, specifically at H3K18la - a newly characterized epigenetic modification influencing gene expression and potentially contributing to cardiomyocyte dysfunction. We hypothesize that cardiac-specific knockout of CA12 will reduce doxorubicin- induced glycolysis and lactate production, thereby protecting cardiac function by preventing the activation of cardiac dysfunction genes via histone lactylation. In Aim 1, we will investigate the role of CA12-mediated glycolysis in AIC by assessing whether inhibition of CA12 can protect against AIC in iCMs derived from patients who have experienced doxorubicin-induced cardiotoxicity (DoxTox patients) and in cardiomyocyte-specific CA12 knockout (Car12 cKO) mice. In Aim 2, we will explore the role of glycolysis-mediated histone lactylation in AIC and its relationship with CA12 by examining how increased lactate production leads to histone lactylation at H3K18la, epigenetically activating cardiomyocyte dysfunction genes. Ultimately, these findings have the potential to improve the long-term cardiovascular health of cancer survivors by informing the development of safer chemotherapy regimens and adjunctive therapies that protect cardiac function, thereby addressing a critical unmet need in cardio-oncology.
