In Vitro and In Vivo Analyses of 14-O-Acylanthracyclines

性状（由申请方提供）：以N-苄基阿霉素-14-戊酸酯（AD 198）和N-苄基阿霉素-14-新戊酸酯（AD 445）为代表的14-O-酰基蒽环类药物在功能上不同于多柔比星（DOX）和其他DNA结合蒽环类药物。AD 198和AD 445定位于细胞质中，特异性结合蛋白激酶C（PKC）的C1调节结构域，并以快速触发增殖细胞凋亡的方式激活PKC。正如我们所示，AD 198和AD 445激活线粒体相关的PKC-d全酶，以触发32D.3常规骨髓细胞中的线粒体膜去极化和细胞色素c释放。与非PKC结合的蒽环类药物如DOX、AD 198和AD 445不同，在多种细胞类型中，细胞毒性不受Bcl-2或Bcl-XL抗凋亡蛋白表达或p53蛋白功能障碍的影响。AD 198和AD 445还规避了由多药物转运蛋白和改变的拓扑异构酶II活性赋予的抗性。在体内，AD 198显示出大于DOX的杀肿瘤活性，具有降低的骨髓抑制和无显著的器官毒性，包括缺乏心脏毒性。该提案描述了AD 198和AD 445分析的下一阶段，导致临床试验。本研究的总体目标是首先分析AD 198和AD 445激活PKC导致快速凋亡的机制。我们将开始与32 D.3细胞，以确定药物诱导的PKC-d激活如何导致线粒体去极化和细胞色素c释放的方式，不受Bcl-2或Bcl-XL状态。其次，鉴于迄今为止这些药物在体外和体内的明显优势， 在体内，我们将通过评估AD 198和AD 445对表达多种抗性机制（Bcl-21 P-gplMRPI p53 -1-）的植入的HL 60人白血病细胞的体内功效来继续这些研究。这些研究的完成将更详细地建立AD 198和AD 445诱导细胞凋亡的机制，并确定这些新型药物是否可以规避体内多种临床相关的耐药性机制。

DESCRIPTION (provided by applicant): The 14-O-acyl anthracyclines, represented by N-benzyladriamycin-14-valerate (AD 198) and N-benzyladriamycin-14-pivalate (AD 445), are functionally distinct from doxorubicin (DOX) and other DNA-binding anthracyclines. AD 198 and AD 445 localize in the cytoplasm, specifically bind to the C1 regulatory domain of protein kinase C (PKC) and activate PKC in a manner that rapidly triggers apoptosis in proliferating cells. As we have shown, AD 198 and AD 445 activate mitochondrial-associated PKC-d holoenzyme to trigger mitochondrial membrane depolarization and cytochrome c release in 32D.3 routine myeloid cells. Unlike non-PKC binding anthracyclines, such as DOX, AD 198 and AD 445 cytotoxicity is unaffected by Bcl-2 or Bcl-XL anti-apoptotic protein expression or p53 protein dysfunction in a variety of cell types. AD 198 and AD 445 also circumvent resistance conferred by multidrug transport proteins and altered topoisomerase II activity, In vivo, AD 198 demonstrates tumoricidal activity greater than DOX, with reduced myelosuppression and no significant organ toxicity, including a lack of cardiotoxicity. This proposal describes the next stages of analysis of AD 198 and AD 445 leading to clinical trials. The overall goals of this study are first, to analyze the mechanism by which PKC activation by AD 198 and AD 445 leads to rapid apoptosis. We will begin with 32D.3 cells to determine how drug-induced PKC-d activation leads to mitochondrial depolarization and cytochrome c release in a manner that is unaffected by Bcl-2 or Bcl-XL status. Second, given the clear advantage of these agents over DOX thus far in vitro and in vivo, we will continue these studies by assessing the in vivo efficacy of AD 198 an d AD 445 against implanted HL60 human leukemia cells expressing a variety of resistance mechanisms (Bcl-21P-gplMRPIp53-1-). Completion of these studies will establish in greater detail a mechanism of AD 198 and AD 445 induction of apoptosis and determine whether these novel agents can circumvent multiple, clinically relevant mechanisms of drug resistance in vivo.