Chemotherapy is one of the most important methods in the treatment of cancer. However, development of drug resistance during chemotherapy is the leading cause of treatment failure and decreased survival in cancer patients. Multidrug resistance (MDR) is one of the extensively studied forms of drug resistance for more than 30 years. The members of ATP‐binding cassette protein family are responsible for multidrug resistance with P‐glycoprotein as most representative transporter. To overcome multidrug resistance, pharmacological modulation of the transporters by efflux pump inhibitors seem to be the first choice, but preclinical studies did not lead to clinical applications. Therefore, a systematical research for pharmacophor structures is a promising strategy to increase the efficacy of those drugs still influencing multidrug resistance. In this study a range of phenothiazine derivatives was synthesizied with systematical variation of three molecule domains. The biochemical determination of multidrug resistance reversal activity was achieved with the crystalviolet assay on LLC‐PK1/MDR1 cells. The results will be discussed considering of hypotheses in the literature directed to new structure‐acitivity relationships to overcome drug resistance in the future.

中文翻译：

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作为 MDR 逆转剂的新型吩噻嗪和相关药物的合成和生化表征

化疗是治疗癌症最重要的方法之一。然而，化疗期间耐药性的发展是癌症患者治疗失败和生存率下降的主要原因。多药耐药 (MDR) 是 30 多年来广泛研究的耐药形式之一。ATP 结合盒蛋白家族的成员负责以 P-糖蛋白作为最具代表性的转运蛋白的多药耐药性。为了克服多药耐药性，外排泵抑制剂对转运蛋白的药理学调节似乎是首选，但临床前研究并未导致临床应用。因此，对药效基团结构进行系统研究是提高那些仍影响多药耐药性的药物疗效的有前途的策略。在这项研究中，一系列吩噻嗪衍生物合成了三个分子结构域的系统变异。多药耐药逆转活性的生化测定是通过对 LLC-PK1/MDR1 细胞的结晶紫测定实现的。将考虑文献中关于新的结构-活性关系以克服未来耐药性的假设来讨论结果。