Glutaredoxin, Glutathione Metabolism and Lung Cancer

项目总结 谷胱甘肽(GSH)是一种小的硫醇抗氧化剂，对维持氧化还原动态平衡至关重要，并增加 谷胱甘肽存在于KRAS突变的肺腺癌中。谷胱甘肽也可导致S-谷胱甘肽基化 (PSSG)，谷胱甘肽与蛋白质中反应性半胱氨酸的结合，这种结合可以被蛋白质中的脱氢酶逆转。 谷胱甘肽还原酶(GLRX)。虽然谷氧还蛋白/PSSG系统已经成为 氧化还原信号，对其在肺腺癌(LUAD)中的破坏作用知之甚少。我们已经制作了令人兴奋的 发现GLRX在LUAD中表达降低，KrasG12D诱导的肺肿瘤发生 在缺乏Glrx的小鼠中增强。在氧化还原蛋白质组学筛查中，我们发现S-谷胱甘肽基化增加 卵巢肿瘤去泛素酶，OTUB1，最近被发现是XC-系统的调节因子。系统XC-IS 一种半胱氨酸/谷氨酸逆向转运体，输出谷氨酸和进口半胱氨酸，而半胱氨酸又被细胞内还原。 对于半胱氨酸，谷胱甘肽合成中的限速氨基酸。系统XC-由SLC7A11和 SLC3A2。OTUB1与SLC7A11结合，防止其泛素化和蛋白酶体降解。我们已经做出了 令人兴奋的发现，OTUB1的S-谷胱甘肽基化在SLC7A11的稳定中起重要作用，导致 谷胱甘肽升高。与邻近对照组织相比，OTUB1和SLC7A11的表达增加 路德。这些令人兴奋的发现引导我们假设，在突变体中谷氧还蛋白的表达减少 KRAS诱导的肺腺癌通过S诱导XC系统活性增加 卵巢肿瘤脱泛素酶1(OTUB1)谷胱甘肽基化，增强谷胱甘肽，促进 肺癌细胞的存活率。此外，我们假设增加谷氧还蛋白的途径将会减少。 GSH水平导致顺铂诱导的肺癌细胞杀伤力增强。在具体目标1中，我们 将决定GLRX状态是否控制KrasG12D诱导的肿瘤形成。具体目标2建议 阐明OTUB1 S-谷胱甘肽基化和XC-系统在KrasG12D-GSH增强中的重要性- 诱导肿瘤，而在特定的目标3，我们的目标是解决AAV介导的GLRX转导对 顺铂诱导原代LUAD肿瘤器官和KrasG12D驱动的小鼠肿瘤杀伤。完成 这一建议的提出将为了解GLRX-蛋白S-谷胱甘肽氧化还原系统在 LUAD的发病机制，并为在肺部肿瘤中增加GLRX以促进杀伤提供了理论基础。 GLRX的药物开发有可能为对抗LUAD提供新的治疗策略， 结合标准护理治疗。

PROJECT SUMMARY Glutathione (GSH) is a small thiol antioxidant that is critical in maintaining redox homeostasis, and increases in glutathione occur in KRAS-mutant lung adenocarcinoma. Glutathione can also lead to S-glutathionylation (PSSG), the conjugation of GSH to reactive cysteines in proteins, which can be reversed by the de- glutathionylase, glutaredoxin (GLRX). While the glutaredoxin/PSSG system has emerged as a key regulator of redox signaling, little is known about its disruption in lung adenocarcinoma (LUAD). We have made the exciting discovery that GLRX expression is decreased in human LUAD and that KrasG12D-induced lung tumorigenesis is enhanced in mice lacking Glrx. In a redox proteomics screen we revealed increases in S-glutathionylation of ovarian tumor deubiquitinase, OTUB1, which was recently identified as a regulator of System XC-. System XC- is a cystine/glutamate antiporter that exports glutamate and imports cystine, which is in turn reduced intracellularly to cysteine, the rate limiting amino acid in glutathione synthesis. System XC- is composed of SLC7A11 and SLC3A2. OTUB1 binds to SLC7A11 to prevent its ubiquitination and proteasomal degradation. We have made the exciting discovery that S-glutathionylation of OTUB1 is important in the stabilization of SLC7A11, leading to increases in GSH. Compared to adjacent control tissue, expression of OTUB1 and SLC7A11 are increased in LUAD. These exciting findings led us to hypothesize that decreases in glutaredoxin expression in mutant KRAS-driven lung adenocarcinoma cause increases in system XC- activity through the S- glutathionylation of ovarian tumor deubiquitinase 1 (OTUB1), augmenting glutathione and promoting survival of lung cancer cells. Furthermore, we hypothesize that avenues to augment glutaredoxin will diminish GSH levels leading to increased potency of cisplatin-induced killing of lung cancer cells. In Specific Aim 1 we will determine whether GLRX status controls KrasG12D-induced tumorigenesis. Specific Aim 2 proposes to address the importance of OTUB1 S-glutathionylation and System XC- in the augmentation of GSH in KrasG12D- induced tumors while in Specific Aim 3 we aim to address the impact of AAV-mediated transduction of GLRX on cisplatin-induced tumor killing in primary LUAD tumor organoids and KrasG12D-driven tumors in mice. Completion of this proposal will provide new insights into the role of the GLRX-protein S-glutathionylation redox system in the pathogenesis of LUAD and offers a rationale for augmenting GLRX in lung tumors in order to promote killing. The pharmaceutical development of GLRX has the potential to offer new therapeutic strategies to combat LUAD, in combination with standard of care therapy.