Department of Molecular Biology, Rutgers University, Piscataway, New Jersey.
Program of Surgical Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, New Jersey.
Mol Cancer Ther. 2019 Aug;18(8):1355-1365. doi: 10.1158/1535-7163.MCT-18-1080. Epub 2019 Jun 13.
Chemotherapy and radiation are more effective in wild-type (WT) p53 tumors due to p53 activation. This is one rationale for developing drugs that reactivate mutant p53 to synergize with chemotherapy and radiation. Zinc metallochaperones (ZMC) are a new class of mutant p53 reactivators that restore WT structure and function to zinc-deficient p53 mutants. We hypothesized that the thiosemicarbazone, ZMC1, would synergize with chemotherapy and radiation. Surprisingly, this was not found. We explored the mechanism of this and found the reactive oxygen species (ROS) activity of ZMC1 negates the signal on p53 that is generated with chemotherapy and radiation. We hypothesized that a zinc scaffold generating less ROS would synergize with chemotherapy and radiation. The ROS effect of ZMC1 is generated by its chelation of redox active copper. ZMC1 copper binding ( ) studies reveal its affinity for copper is approximately 10 greater than Zn We identified an alternative zinc scaffold (nitrilotriacetic acid) and synthesized derivatives to improve cell permeability. These compounds bind zinc in the same range as ZMC1 but bound copper much less avidly (10- to 10-fold lower) and induced less ROS. These compounds were synergistic with chemotherapy and radiation by inducing p53 signaling events on mutant p53. We explored other combinations with ZMC1 based on its mechanism of action and demonstrate that ZMC1 is synergistic with MDM2 antagonists, BCL2 antagonists, and molecules that deplete cellular reducing agents. We have identified an optimal Cu:Zn binding ratio to facilitate development of ZMCs as chemotherapy and radiation sensitizers. Although ZMC1 is not synergistic with chemotherapy and radiation, it is synergistic with a number of other targeted agents.
化疗和放疗在野生型（WT）p53 肿瘤中更有效，这是因为 p53 的激活。这是开发重新激活突变 p53 以与化疗和放疗协同作用的药物的一个基本原理。锌金属载体（ZMC）是一类新的突变 p53 再激活剂，可将锌缺乏的 p53 突变体恢复为 WT 结构和功能。我们假设硫代半卡巴嗪 ZMC1 将与化疗和放疗协同作用。令人惊讶的是，事实并非如此。我们探讨了这种现象的机制，发现 ZMC1 的活性氧（ROS）活性否定了化疗和放疗产生的 p53 信号。我们假设生成较少 ROS 的锌支架将与化疗和放疗协同作用。ZMC1 的 ROS 效应是由其对氧化还原活性铜的螯合产生的。ZMC1 铜结合（ ）研究表明，其对铜的亲和力大约比 Zn 高 10 倍。我们确定了另一种锌支架（氮三乙酸），并合成了衍生物以提高细胞通透性。这些化合物在与 ZMC1 相同的范围内结合锌，但结合铜的亲和力要低得多（低 10 至 10 倍），并产生较少的 ROS。这些化合物通过诱导突变型 p53 的 p53 信号事件与化疗和放疗协同作用。我们根据其作用机制探索了与 ZMC1 的其他组合，并证明 ZMC1 与 MDM2 拮抗剂、BCL2 拮抗剂和消耗细胞还原剂的分子协同作用。我们已经确定了最佳的 Cu:Zn 结合比，以促进 ZMC 作为化疗和放疗增敏剂的开发。尽管 ZMC1 与化疗和放疗不协同，但它与许多其他靶向药物协同作用。
