Redox modulation - Impact on Tumor Growth and Therapeutic Anticancer Efficacy

尽管癌症生物学取得了进展，但耐药性仍然是患者和临床医生面临的主要障碍。多流 癌症治疗的部分作用是通过增加活性氧物种(ROS)的产生来发挥作用，这通常会导致肿瘤 消退后肿瘤复发和治疗耐药。此前，凯尔卡和他的同事们 在含有NOX2蛋白ROS缺陷的巨噬细胞的小鼠肿瘤进展中(Kelkka等人，2013年)。 他们的结论是，当ROS出现时，免疫细胞对肿瘤的转移和进展更有效 巨噬细胞的产生受到抑制。另一方面，其他人已经证明了 致癌和我们固有的抗氧化系统，如硫氧还蛋白还原酶(TrxR)系统和 谷胱甘肽还原酶系统(Gorrini等人，2013年)。随着癌变的进展，细胞产生的水平越来越高 关于Ros的。肿瘤细胞通过硫氧还蛋白等适应性抗氧化反应应对高水平的ROS 还原酶系统。然而，当这个系统在肿瘤细胞内受损时，体内的肿瘤进展和 转移可能被显著抑制(Yoo等人，2006年)。 鉴于这些发现，我们认为，肿瘤细胞对目前的治疗方法产生抵抗力的部分原因是全身 ROS的产生增加，这1)不足以促进肿瘤细胞的死亡，因为它们具有适应性 抗氧化反应，以及2)ROS水平升高会损害免疫细胞有效地对抗肿瘤细胞。 因此，我们建议，有效的抗癌治疗需要一种综合的方法。我们假设 抗氧化系统失调的肿瘤细胞会显著退化，宿主的免疫 在低ROS条件下，反应将被准备好根除剩余的恶性肿瘤。 这个被提议的PHD项目的重点是研究这一假设，并表征最优的氧化还原 肿瘤消退的条件。我们计划使用两个成熟的小鼠肿瘤模型来实现这一点：1) 转移性B16F10黑色素瘤和2)转移性Lewis肺癌LLC1。我们将在 体外检测这些肿瘤模型中的基线氧化还原系统，使用siRNA或CRISPR进行改变。我们还将 看看活着的宿主体内的肿瘤进展。我们将使用六个小鼠品系来帮助我们了解 宿主氧化还原生物学，在免疫细胞和系统中，对癌症的反应。具体地说，我们将使用 关键表型：B6.129P2-Txnrd1tm1Marc，B6.129P2-Txnrd1Cond，BQ.Ncf1m1J(Ncf1突变体 BQ.Ncf4(Ncf4突变小鼠)、BQMN(仅在巨噬细胞中表达Ncf1)和BQ.Tn3 有条件的敲入小鼠。最后，我们将研究用Auranofin和其他药物挑战肿瘤氧化还原系统 TrxR1抑制剂。

Despite advances in cancer biology, drug resistance is a major obstacle to patients and clinicians. Many current cancer therapeutics work in part by elevating reactive oxygen species (ROS) production, often leading to tumor regression followed by tumor reoccurrence and therapeutic resistance. Previously, Kelkka and coworkers looked at tumor progression in mice with macrophages deficient in ROS from the protein NOX2 (Kelkka et al., 2013). They concluded that immune cells are more efficacious against metastasis and tumor progression when ROS production in macrophages is inhibited. On the other hand, others have demonstrated the relationship between carcinogenesis and our innate antioxidant systems such as the thioredoxin reductase (TrxR) system and the glutathione reductase system (Gorrini et al., 2013). As carcinogenesis progress, cells produce increasing levels of ROS. Tumor cells cope with high levels ROS via an adaptive antioxidant response such as the thioredoxin reductase system. However, when this system is impaired within tumor cells, in vivo tumor progression and metastasis may be significantly inhibited (Yoo et al., 2006). Given these findings, we believe that tumor cells become resistant to current therapies in part by the systemic increase of ROS production, which 1) is insufficient to promote cell death in tumor cells because of their adaptive antioxidant response, and 2) elevated levels of ROS impairs immune cells from effectively combating tumor cells. Therefore we propose that a combined approach is required for effective anticancer therapy. We hypothesize that tumor cells with dysfunctional antioxidant systems will significantly regress and that the host’s immune response, under low ROS conditions, will be primed to eradicate the remaining malignancy. The focus of this proposed PhD project is to investigate this hypothesis and characterize the optimal Redox conditions for tumor regression. We plan to accomplish this using two well-established murine tumor models: 1) the metastatic B16F10 melanoma and 2) the metastatic Lewis Lung Carcinoma, LLC1. We will characterize in vitro the baseline Redox systems in these tumor models, make alterations using siRNA or CRISPR. We will also look at tumor progression in living hosts. We will use six mouse strains to help us understand the significance of host Redox biology, in both the immune cells and systemically, in response to cancer. Specifically, we will use mouse models with key phenotypes: B6.129P2-Txnrd1tm1Marc, B6.129P2-Txnrd1Cond, BQ.Ncf1m1J (Ncf1 mutant mice), BQ.Ncf4 (Ncf4 mutant mice), BQMN (expressing Ncf1 in macrophages only) and BQ.TN3 conditional knock-in mice. Finally, we will study tumor redox systems challenged with Auranofin and other TrxR1 inhibitors.