Modeling the role of the genome in chemotherapy induced cardiotoxicity using iPSC

Doxorubicin is a well-established and highly effective chemotherapy drug commonly used to treat multiple cancers, but its use is limited by a serious side effect: doxorubicin causes toxicity in cardiomyocytes, causing damage to the heart. Acute doxorubicin-induced cardiotoxicity occurs in ~11% of patients and long-term cardiotoxic side effects, which can manifest up to 10 years after treatment, are observed in up to 36% of patients. Currently we cannot predict which patients will develop cardiotoxicity and, at present, oncologists do not assess patient-specific genomic data before deciding on doxorubicin dose. In initial studies, we developed and validated a set of tools for assessing DIC in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). We established that hiPSC-CMs, derived from patients who have developed DIC, accurately recapitulate the susceptibility phenotype in vitro. We have identified SNPs in three genes that are predicted to be highly associated with DIC (P=10^-9 or 10^-5). However, before any SNP can be utilized in clinical practice, its validity must be confirmed through studies linking that SNP to a mechanism for DIC. In this funded grant we intend to use the hiPSC-CM model to perform detailed characterization of the function of these genes identified through SNP studies in DIC. For Aim 1 of this funded grant we proposed to generate hiPSC lines from patients with the highest probability candidate SNPs. In Aim 2 we proposed to use the assays established in the pilot study to assess the effect of these SNPs on susceptibility to DIC and also isogenic hiPSC lines genetically modified to over-express or knock-down the whole genes identified to confirm the mechanism of each gene variant. In Aim 3 we intended to continue to expand this work to validate 15 additional high-risk SNP hits to ultimately develop a high-throughput platform for screening cardiotoxicity of novel anthracycline analogues and cardioprotective agents in a patient-specific manner (Aim 4). The overall aim of this proposal is to use patient-specific hiPSC-CMs to help elucidate the mechanisms through which these SNPs affect cardiotoxicity.