DRUG SELECTIVITY IN CARDIAC AND MDR TUMOR CELLS

阿霉素是一种临床上广泛使用的抗肿瘤药物，被认为是 大多数其他癌症化疗药物通过影响复制 积极分裂肿瘤和正常细胞的机制。可惜这 药物还影响心脏的非分裂细胞。此外，本发明还提供了一种方法， 阿霉素是由一个特定的细胞机制，称为多- 耐药（MDR）。我们已经开发了体外系统， 实验室中，心脏毒性以及杀肿瘤和MDR 可以在细胞和亚细胞水平上研究药物的机制。 我们发现了负电膜的根本区别 这些细胞的潜力，可能部分解释了差异细胞 阿霉素的吸引力和敏感性，这是积极的- 充电。我们建议研究阿霉素的电荷和亲脂性 和相关的类似物影响它们在体内的选择性积累和毒性， 心肌细胞（MDR-）和MDR-和MDR+肿瘤细胞系。 然而，这些蒽环类药物结构复杂，使得它们的 难以用于结构/功能研究 心脏毒性和MDR。因此，我们计划使用一系列简单的 亲脂阳离子化合物（胍和吡啶）作为模型， 探索MDR-和MDR+细胞中的药物选择性机制。最近， 利用该策略，我们发现（Cancer Research 52：6385-6389，1992）， 需要芳族部分和一定程度的亲脂性， 这些简单的阳离子化合物被MDR +细胞识别。这 信息将用于进一步表征物理/化学性质 MDR识别和MDR诱导的要求， 调变本提案的具体目的是澄清 化学电荷和亲脂性影响这些简单的化合物， 以及蒽环类抗生素，以解释其差异积累， MDR-和MDR+细胞中的细胞毒性。这些活动的总体目标 研究的目的是增加对相关机制的理解 在ADM诱导的心脏毒性和多药耐药性中， 最终可以转化为新的临床方案设计， 对MDR +肿瘤细胞具有最大活性且对MDR+肿瘤细胞具有最小活性的蒽环类药物 对心肌细胞的有害影响。 我们的视频计算机化系统将被用来分析药物对 敏感（非MDR）的心脏细胞功能和活力。 荧光显微镜、高压液相色谱和 放射性探针将用于测量细胞内药物蓄积 和跨膜电位。

Adriamycin, a clinical widely used anti-tumor agent, is thought to work as most other cancer chemotherapeutic drugs by affecting the replicating machinery of actively dividing tumor and normal cells. Unfortunately, this agent also affects the non-dividing cells of the heart. In addition, Adriamycin is recognized by a specific cellular mechanism, termed multi- drug resistance (MDR). In vitro systems have been developed in our laboratories in which cardiotoxic as well as tumoricidal and MDR mechanisms of drugs can be studied, at the cellular and subcellular level. We have uncovered fundamental differences in the electronegative membrane potentials of these cells that may in part explain differential cellular attraction of, and sensitivity to, Adriamycin, which is positively- charged. We propose to study how charge and lipophilicity of Adriamycin and related analogs affect their selective accumulation and toxicity in cardiac-muscle cells (MDR-) and in MDR- and MDR+ tumor cell lines. These anthracyclines however, are complex in structure which makes their use difficult for investigational structure/function studies of cardiotoxicity and MDR. We therefore plan to use a series of simple lipophilic-cationic compounds (guanidiniums and pyridiniums) as a model to explore mechanisms of drug selectivity in MDR- and MDR+ cells. Recently, utilizing this strategy we found (Cancer Research 52:6385-6389, 1992) that an aromatic moiety and a certain degree of lipophilicity are required for these simple cationic compounds to be recognized by MDR + cells. This information will be used to further characterize the physical/chemical requirements for MDR recognition as well as for MDR induction and modulation. The specific aims of this proposal are to clarify the effects that chemical charge and lipophilicity impact on these simple compounds as well as on anthracyclines, to explain their differential accumulation and consequent cytotoxicity in MDR- and MDR+ cells. The overall goal of these studies is to increase understanding of the underlying mechanisms involved in both ADM-induced cardiotoxicity and multiple drug resistance, which could eventually translate into new designs of clinical protocols using anthracyclines with maximal activity toward MDR + tumor cells and minimal detrimental effects on cardiac cells. Our video-computerized system will be used to assay effects of drugs on sensitive (non-MDR) cardiac cell function and viability in vitro. Fluorescence microscopy, high pressure liquid chromatography and radioactive probes will be used to measure intracellular drug accumulation and transmembrane potentials.