ANTHRACYCLINE CARDIOTOXICITY: AN IN VITRO MODEL

虽然蒽环类药物，特别是阿霉素(ADM)， 已被证明对治疗广谱的人类 肿瘤，心脏毒性，经常导致致命的充血性心脏 失败，仍然是一个严重的剂量限制副作用。为了 研究阿霉素性心肌病的发病机制 开发了一种心肌细胞模型，在该模型中， 体内描述的ADM可以在体外模拟。使用这个 模型中，我们发现心肌细胞堆积 显著增加了ADM的数量，并经历了 与心脏来源的成纤维细胞相比，细胞损伤。这 观察与我们的发现相结合，心肌和 多种癌细胞类型与Friend白血病细胞 优先积累线粒体定位染料， 罗丹明123号。ADM和罗丹明123的共同之处是 它们在生理pH下都带正电荷。我们的工作 假说是心肌、癌细胞数量众多 类型和朋友白血病细胞具有类似的机制 增强了正电荷的积累和灵敏度 蒽环类和罗丹明类药物。 我们的具体目标是确定(1)为什么心肌，一个 癌细胞系和Friend白血病细胞的数量 积累大量带正电荷的亲脂性 以及(2)是否增加。 膜电位有助于增加药物蓄积 以及对这些细胞类型的敏感性。最终目标是 找出导致差异敏感性的机制 在预防或减少心脏毒性的同时，使用蒽环类药物 提高已知或迄今已知的抗肿瘤药物的有效性 未发现的蒽环类药物和罗丹明类药物。使用荧光法 显微镜、激光流式细胞术、高压液体 高效液相色谱、克隆分析和我们的计算机化 视频心脏细胞功能分析仪，我们计划调查 不同类型药物的细胞蓄积和细胞毒性差异 蒽环类、罗丹明和其他相关化合物。vbl.使用 多种抗性调节剂(钙通道和 钙调蛋白抑制剂)，我们计划找出那些效果最差的 论变时性和变力性心肌细胞的功能和最大 克服对蒽环类药物和罗丹明类药物耐药性的效果 在癌细胞中。通过膜片钳技术，我们将测量 心肌、肿瘤和ADM的膜电位 敏感和耐药的Friend白血病细胞并评估其 与药物积累和药物敏感性相关的重要性。

Although the anthracyclines, particularly Adriamycin (ADM), have been shown to be useful in treating a broad spectrum of human tumors, cardiotoxicity, often leading to fatal congestive heart failure, remains a serious dose limiting side effect. In order to study the mechanism of ADM-induced cardiomyopathy, we developed a cardiac cell model in which several of the effect of ADM described in vivo can be simulated in vitro. Using this model we found that cardiac-muscle cells accumulate significantly greater amounts of ADM and undergo increased cellular damage as compared to cardiac-derived fibroblasts. This observation was coupled with our findings that cardiac-muscle and a number of carcinoma cell types and Friend leukemia cells preferentially accumulate the mitochondrial localizing dye, rhodamine 123. ADM and rhodamine 123 share in common that they are both positively-charged at physiologic pH. Our working hypothesis is that cardiac-muscle, a number of carcinoma cell types and Friend leukemia cells have similar mechanisms for enhanced accumulation of and sensitivity of positively-charged anthracyclines and rhodamines. Our specific aims are to determine (1) why cardiac-muscle, a number of carcinoma cell lines and Friend leukemia cells accumulate high amounts of positively-charged lipophilic anthracyclines and rhodamines and (2) whether increased membrane potentials contribute to increased drug accumulation and sensitivity in these cell types. The ultimate goal is to identify mechanisms responsible for differential sensitivity to anthracyclines in order to prevent or reduce cardiotoxicity while improving the antitumor effectiveness of known or heretofore undiscovered anthracyclines and rhodamines. Using fluorescence microscopy, laser flow cytometry, high pressure liquid chromatography (HPLC), clonogenic assays and our computerized video cardiac cell function analyzer, we plan to investigate differential cellular accumulation and cytotoxicity of a variety of anthracyclines, rhodamines, and other related compounds. Using a number of modulators of resistance (calcium channel and calmodulin inhibitors), we plan to identify those with least effect on chronotropic and inotropic cardiac cell function and maximum effect on overcoming resistance to anthracyclines and rhodamines in cancer cells. By patch clamp technique, we will measure membrane potentials in cardiac-muscle, carcinoma and ADM- sensitive and resistant Friend leukemia cells and assess its importance relative to drug accumulation and chemosensitivity.