Molecular Toxicology, Global Safety Assessment UK, Innovative Medicines, AstraZeneca R&D, Macclesfield, SK10 4TG, UK.
Toxicol Sci. 2013 Apr;132(2):317-26. doi: 10.1093/toxsci/kft005. Epub 2013 Jan 12.
Morphological damage to cardiomyocytes or loss of viability (structural cardiotoxicity) is a common cause of attrition in preclinical and clinical drug development. Currently, no predictive in vitro approaches are available to detect this liability early in drug discovery, and knowledge of the mechanisms involved is limited. Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) and the rat myoblastic H9c2 cell lines were used to phenotypically profile a panel of structural cardiotoxins by live-cell fluorescent imaging of mitochondrial membrane potential, endoplasmic reticulum integrity, Ca(2+) mobilization, and membrane permeability combined with an assessment of cell viability (ATP depletion). Assay results were normalized to known therapeutically relevant concentrations. By comparing the outcome of each assay to the known in vivo effects, hESC-CMs offered an improved model over H9c2 cells for the detection of structural cardiotoxicity at therapeutically relevant concentrations. Inhibition of the spontaneously beating phenotype, a feature of stem cell-derived cardiomyocytes, revealed some degree of cardioprotection following 10 out of 13 structural cardiotoxins, illustrating the intricate relationship between the function and structure of cardiomyocytes. Classification of structural cardiotoxins into mechanistic themes revealed mitochondria and calcium mobilization to be major distal targets, with only 4 out of 15 compounds affecting contractile function in freshly isolated canine cardiomyocytes at therapeutically relevant concentrations. Our data demonstrate the utility of hESC-CMs during drug development to support structural cardiotoxicity hazard identification and to gain insight into the intricate mechanisms implicated in structural cardiotoxicity.
心肌细胞的形态损伤或活力丧失（结构心脏毒性）是临床前和临床药物开发中淘汰的常见原因。目前，在药物发现的早期阶段，还没有可预测的体外方法来检测这种毒性，而且对涉及的机制的了解也有限。使用人胚胎干细胞衍生的心肌细胞（hESC-CMs）和大鼠成肌细胞 H9c2 细胞系，通过活细胞荧光成像检测线粒体膜电位、内质网完整性、Ca(2+)动员和膜通透性，并结合细胞活力（ATP 耗竭）评估，对一组结构心脏毒素进行表型分析。将测定结果归一化为已知的治疗相关浓度。通过将每种测定的结果与已知的体内效应进行比较，hESC-CMs 为在治疗相关浓度下检测结构心脏毒性提供了优于 H9c2 细胞的模型。自发搏动表型的抑制，这是干细胞衍生的心肌细胞的一个特征，表明在 13 种结构心脏毒素中有 10 种在治疗相关浓度下具有一定程度的心脏保护作用，这说明了心肌细胞的功能和结构之间存在复杂的关系。将结构心脏毒素分类为机制主题表明线粒体和钙动员是主要的远端靶标，只有 4 种化合物在治疗相关浓度下影响新鲜分离的犬心肌细胞的收缩功能。我们的数据表明，在药物开发过程中，hESC-CMs 可用于支持结构心脏毒性的危害识别，并深入了解结构心脏毒性所涉及的复杂机制。
