Modeling Susceptibility to Chemotherapy-Induced Cardiotoxicity Using Human iPSCs

描述（由申请人提供）：多柔比星是一种公认的高效化疗药物，常用于治疗多种癌症，如淋巴瘤、白血病、卵巢癌、肺癌和乳腺癌，但其使用受到心脏毒性的限制。心脏毒性的范围可以从无症状的左心室射血分数降低到高度症状性心力衰竭（III至IV级）。急性阿霉素诱导的心脏毒性（DIC）发生在约11%的患者和长期的心脏毒性副作用，可以表现为长达10年的治疗后，观察到高达36%的患者。目前，我们无法预测哪些患者会发生心脏毒性。填补我们对DIC机制以及如何最好地预防DIC的知识中的重大空白的主要障碍是缺乏良好的人类模型，这是由于无法获得患者特异性的人类心肌细胞样品，以及难以在体外分离和维持人类心肌细胞。动物模型受到动物和人类心肌细胞之间显著功能差异的限制。这一障碍现在已经被人类诱导多能干细胞（iPSC）产生的最新进展所克服，其中患者的体细胞可以被重新编程为多能性并在体外无限期地维持。然后，这些iPSC可以有效地分化为iPSC衍生的心肌细胞（iPSC-CM），并进一步详细研究。在我们的初步研究中，我们已经开发并验证了一套用于评估人iPSC-CM中DIC的工具。我们已经确定，iPSC-CM，来自已发展DIC的患者，准确地概括了体外易感性表型。单核苷酸多态性（SNP）研究已经确定了几个SNP，预计与DIC高度相关（P=10-9至10-5）。因此，在目标1中，我们将从100名用阿霉素治疗的癌症患者中产生iPSC系，其中50名经历了心脏毒性，50名没有。在目标2中，我们将使用在我们的试点研究中建立的检测方法来评估DIC的易感性，并进行RNA-seq和eQTL定位以发现新的SNP。在目标3中，我们将使用转录激活因子样效应物核酸酶（TALEN）将非常完善的DIC相关SNP引入五个对照iPSC系中，并评估对DIC易感性的影响。因此，R 01提案的总体目标是使用患者特异性iPSC-CM来帮助阐明DIC的分子机制。

DESCRIPTION (provided by applicant): Doxorubicin is a well-established and highly effective chemotherapy drug commonly used to treat multiple cancers such as lymphoma, leukemia, ovary, lung, and breast cancer, but its use is limited by cardiotoxicity. Cardiotoxicity can range from asymptomatic reduction in left ventricular ejection fraction to highly symptomatic heart failure (Class III to IV). Acute doxorubicin-induced cardiotoxicity (DIC) 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. A major hurdle in filling the significant gaps in our knowledge about the mechanisms of DIC and how best to prevent it is the lack of good human models, due to the inaccessibility of patient-specific human cardiomyocyte samples, and the difficulty in isolating and maintaining human cardiomyocytes in vitro. Animal models are limited by significant functional disparities between animal and human cardiomyocytes. This hurdle has now been overcome by the recent advances in the generation of human induced pluripotent stem cells (iPSCs), in which a patient's somatic cells can be reprogrammed to pluripotency and maintained indefinitely in vitro. These iPSCs can then be efficiently differentiated into iPSC-derived cardiomyocytes (iPSC-CMs) and further studied in detail. In our preliminary studies, we have developed and validated a set of tools for assessing DIC in human iPSC-CMs. We have established that iPSC-CMs, derived from patients who have developed DIC, accurately recapitulate the susceptibility phenotype in vitro. Single nucleotide polymorphism (SNP) studies have identified several SNPs that are predicted to be highly associated with DIC (P=10-9 to 10-5). Hence in Aim 1, we will generate iPSC lines from 100 cancer patients treated with doxorubicin, 50 of whom experienced cardiotoxicity and 50 did not. In Aim 2, we will use the assays established in our pilot studies to assess the susceptibility to DIC and perform RNA-seq and eQTL mapping to discover novel SNPs. In Aim 3, we will introduce a very well established DIC-related SNP into five control iPSC lines using transcription activator-like effector nucleases (TALENs) and assess the effect on DIC susceptibility. Hence the overall aim of this R01 proposal is to use patient-specific iPSC-CMs to help elucidate the molecular mechanisms of DIC.