ANTHRACYCLINE CARDIOTOXICITY: AN IN VITRO MODEL

虽然蒽环类药物，特别是阿霉素（ADM）， 已经显示出可用于治疗广谱的人类 肿瘤、心脏毒性，往往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 为探讨阿霉素诱导心肌病的机制， 开发了一个心脏细胞模型，其中几个影响， 体内描述的ADM可以在体外模拟。 使用此 我们发现心肌细胞会积累 ADM的量显著增加， 与心脏来源的成纤维细胞相比， 这 观察结果与我们的发现相结合， 一些癌细胞类型和Friend白血病细胞 优先积累线粒体定位染料， 罗丹明123。 ADM和罗丹明123有一个共同点， 它们在生理pH值下都带正电荷。我们的工作 假设是心肌中有许多癌细胞 类型和朋友白血病细胞有类似的机制， 增强的正电荷的积累和灵敏度 蒽环类和罗丹明类。 我们的具体目标是确定（1）为什么心肌， 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 蒽环类和罗丹明类，以及（2）是否增加 膜电位有助于增加药物蓄积 和敏感性。 最终目标是 确定对下列问题敏感性不同的机制 蒽环类药物，以防止或减少心脏毒性， 提高已知的或迄今为止的抗肿瘤效果 未被发现的蒽环类和罗丹明类药物。 使用荧光 显微镜，激光流式细胞术，高压液相 高效液相色谱法（HPLC），克隆形成试验和我们的计算机 视频心脏细胞功能分析仪，我们计划调查 不同的细胞积累和细胞毒性的各种 蒽环类、罗丹明类和其他相关化合物。 使用 许多抵抗调节剂（钙通道和 钙调素抑制剂），我们计划找出那些影响最小的 对变时性和变力性心肌细胞功能和最大 对克服蒽环类和罗丹明类耐药性的作用 在癌细胞中。 采用膜片钳技术， 心肌细胞膜电位、癌细胞膜电位、ADM膜电位 敏感和耐药的Friend白血病细胞，并评估其 相对于药物积累和化学敏感性的重要性。

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.