Cancer specific N-alkylaminoferrocene-based prodrugs

基于N-烷基氨基二茂铁(NAAF)的前体药物在活性氧物种(ROS)浓度升高时被激活，形成剧毒物种。这些情况是癌细胞的特征，而正常细胞的体内稳态ROS水平较低。因此，正如我们在体外和体内实验中所证实的那样，NaAF-前体药物比正常细胞更好地杀死癌细胞。在之前DFG资助的项目框架下，我们通过将这些前体药物重定向到溶酶体来增强其疗效，溶酶体中的ROS浓度高于癌细胞胞浆中的ROS浓度。此外，我们证实了这些前药对癌细胞和原代细胞的疗效都不是P53依赖的。最好的NaAF-前体药物在体内的抗癌活性比基于体外数据预测的剂量高20倍。我们观察到，至少一个可能的原因是血液中前体药物的细胞非特异性氧化导致它们失活。在这个项目中，我们将通过氧化还原调节前体药物的二茂铁核心来解决这个问题，而不影响由B-C键断裂启动的所需的癌症特异性ROS触发的激活反应。下一步，我们将通过使用比以前使用的(过氧化氢)反应更活跃的触发剂(过氧亚硝酸盐)来进一步提高前药的疗效，直到nMolar范围。前药将被设计/优化，以实现原位生成的ONOO-a与芳基硼酸触发剂的有效反应，从而避免ONOO-泄漏到环境中，从而可能导致潜在的副作用。所得到的前药的性质将在体外细胞培养实验和体内药物在肿瘤中分布和积累的研究中进行评估，并在NK/淋巴瘤小鼠模型中评估前药的抗肿瘤效果。

N-alkylaminoferrocene-based (NAAF) prodrugs are activated in the presence of elevated concentrations of reactive oxygen species (ROS) with formation of highly toxic species. These conditions are characteristic for cancer cells, whereas normal cells have low homeostatic ROS levels. Therefore, NAAF-prodrugs kill cancer cells preferably over normal ones as we have established in both in vitro and in vivo experiments. In the framework of the previously DFG-funded previous project we enhanced the efficacy of these prodrugs by their redirection to lysosomes, where the ROS concentration is higher than that in cytoplasm of cancer cells. Moreover, we confirmed that the efficacy of the prodrugs towards both cancer cell lines and primary cells is not p53-dependent. The best NAAF-prodrugs exhibit in vivo anticancer activity at >20-fold higher doses than those predicted based on in vitro data. We observed that at least one of the possible reasons for that is a cell-unspecific oxidation of prodrugs in blood leading to their deactivation. In this project we will approach this problem by redox-tuning of the ferrocene core of the prodrugs without affecting the desirable, cancer specific ROS-triggered activation reaction initiated by cleavage of the B-C bond. Next, we will further enhance the efficacy of the prodrugs down to the nMolar range by making use of a substantially more reactive trigger (peroxynitrite) than that previously used (hydrogen peroxide). The prodrug will be designed / optimized to achieve the efficient reaction of in situ generated ONOO-a with the arylboronic acid trigger thereby avoiding the leakage of ONOO- to the environment that could cause potential side effects. Properties of the resulting prodrug will be evaluated both in vitro in experiments with cell cultures and in vivo in studies of drug distribution and accumulation in tumors and antitumor efficacy of the prodrug in an NK/lymphoma mouse model.