Role of sirtuin 6 in melanoma development and progression

黑色素瘤的发病率正在迅速上升，预计2020年美国将有100,350例黑色素瘤病例。此外， 黑色素瘤是退伍军人中的一个重要问题，也是最常被诊断出的五种癌症之一 在退伍军人事务部癌症患者中。恶性黑色素瘤是最致命的癌症之一，现有的 治疗方法，包括最近批准的BRAF抑制剂，对黑色素瘤并不完全有效 管理层由于后天的抵触。因此，需要新的基于目标的方法来实现 这种肿瘤的治疗。我们有一个正在进行的研究计划，以确定sirtuins在 黑色素瘤。哺乳动物的sirtuin家族由七个成员组成(SIRT1-SIRT7)，它们起着至关重要的作用 在重要的细胞过程中发挥作用，并参与包括癌症在内的各种疾病。的作用 癌症中的SIRT是复杂的，它们似乎有两种功能，取决于细胞环境。近期 研究表明，sirtuin 6(SIRT6)是一种主要的核蛋白，参与调节参与 基因转录、葡萄糖稳态、DNA修复和端粒完整性。SIRT6已被发现 抑制肠道和肝脏的肿瘤形成。然而，SIRT6在皮肤和皮肤中也具有促增殖作用 前列腺癌，这表明它的功能可能与组织和上下文有关。有趣的是，SIRT6有 也被证明调节上皮-间充质转化(EMT)，并促进某些肿瘤的转移 癌症类型。在最近的一项研究中，我们证明了SIRT6在人类黑色素瘤细胞中过表达 和组织，通过shRNA介导的RNA干扰抑制SIRT6导致显著的抗增殖 反应(生长抑制、细胞周期改变、抑制细胞迁移、衰老和自噬 在黑色素瘤细胞中)。我们的初步数据和已发表的研究与其他已发表的 研究为我们研究其作用和潜在的治疗方法提供了强有力的科学前提 SIRT6在黑色素瘤中的意义，并支持我们提出的SIRT6在黑色素瘤中发挥关键作用的假设 黑素细胞转化和黑色素瘤进展以及与其他驱动途径一起，可以 用于治疗黑色素瘤的药物。提出了以下具体目标：1)明确 SIRT6在黑色素瘤发生发展中的作用及其与关键黑色素瘤驱动因素的关系 使用组织微阵列(TMA)的途径，这些组织微阵列是从退伍军人的回溯性黑色素瘤组织创建的 病人。在这一目标中，我们将确定SIRT6在黑色素瘤中的作用以及它与关键的 黑色素瘤驱动通路(RAS/RAF/MEK/ERK-和p16/Cyclin D-CDK4/6-Rb-通路)；2)确定 SIRT6在黑色素瘤中的功能和机制意义在这一目标中，我们将确定 CRISPR/Cas9介导SIRT6缺失对黑色素瘤细胞体内外生长和进展的影响 3)确定SIRT6抑制剂单独及与其他有希望的药物联合应用的治疗意义 体内靶向抗黑色素瘤方法。我们将使用Small来确定SIRT6抑制的效果 分子SIRT6抑制剂单独以及与其他临床相关黑色素瘤治疗(BRAF)联合使用 抑制剂维莫拉非尼和MEK抑制剂曲美替尼)对黑色素瘤的发展、生长和转移的影响 BRAF-PTEN小鼠模型和2)患者来源的异种移植(PDX)。我们预计，我们的研究将确定这一角色， SIRT6在黑色素瘤中的作用机制和相互作用，以及临床前环境中的新组合， 这可能对未来的临床研究有用。这可能最终导致小说的发展 黑色素瘤的诊断、预后和治疗方法。因此，我们建议的研究是相关的， 这对退伍军人的保健具有重要意义，符合退伍军人事务部的使命。

Melanoma incidences are increasing rapidly with 100,350 cases predicted in 2020 in the US. Further, melanoma is a significant problem in Veterans, and it is among the five most frequently diagnosed cancers among VA cancer patients. Malignant melanoma is one of the deadliest forms of cancer, and the existing therapeutics, including recently approved BRAF inhibitors, have not been fully effective in melanoma management due to acquired resistance. Therefore, novel target-based approaches are needed for the management of this neoplasm. We have an ongoing research program to define the role of sirtuins in melanoma. The mammalian sirtuins constitute a family of seven members (SIRT1 – SIRT7), which play critical roles in important cellular processes, and are involved in a variety of diseases, including cancer. The role of SIRTs in cancer is complex, and they appear to have dichotomous functions depending on cell context. Recent studies have implicated sirtuin 6 (SIRT6), a predominantly nuclear protein, in regulating pathways involved in gene transcription, glucose homeostasis, DNA repair and telomere integrity. SIRT6 has been found to suppress tumorigenesis in the intestine and liver. However, SIRT6 also has a pro-proliferative role in skin and prostate cancer, suggesting that its function may be tissue- and context- dependent. Interestingly, SIRT6 has also been shown to modulate epithelial-mesenchymal transition (EMT) and promote metastasis in certain cancer types. In a recent study, we have demonstrated that SIRT6 is overexpressed in human melanoma cells and tissues, and SIRT6 inhibition via shRNA-mediated RNA interference resulted in a marked antiproliferative response (growth inhibition, cell cycle alternation, inhibition of cell migration, senescence and autophagy dysregulation) in melanoma cells. Our preliminary data and published study together with other published research provide a strong scientific premise to our investigation into the role and potential therapeutic significance of SIRT6 in melanoma and supports our proposed hypothesis that SIRT6 plays a critical role in melanocytic transformation and melanoma progression and together with other driver pathways, can be therapeutically exploited for melanoma management. The following specific aims are proposed: 1) To define the role of SIRT6 in melanoma development and progression and its association with critical melanoma driver pathways employing a tissue microarray (TMA) created from retrospective melanoma tissues from Veteran patients. In this aim, we will determine the role of SIRT6 in melanoma as well as its association with critical melanoma driver pathways (RAS/RAF/MEK/ERK-, and p16/cyclin D-CDK4/6-RB- pathways); 2) To determine the functional and mechanistic significance of SIRT6 in melanoma. In this aim, we will determine the effect of CRISPR/Cas9 mediated SIRT6 deletion on growth and progression of melanoma cells in vitro and in vivo; and 3) To determine the therapeutic significance of SIRT6 inhibition alone and in combination with other promising target-based anti-melanoma modalities in vivo. We will determine the effects of SIRT6 inhibition using small molecule SIRT6 inhibitor alone and in combination with other clinically relevant melanoma therapies (BRAF inhibitor, Vemurafenib; and MEK inhibitor, Trametinib) on melanoma development, growth and metastasis in 1) Braf-Pten mouse model, and 2) patient-derived xenografts (PDX). We expect that our study will define the role, mechanism, and interactions of SIRT6 in melanoma as well as novel combinations in pre-clinical settings, which could be useful for future clinical investigations. This may ultimately lead to the development of novel diagnostic, prognostic, and therapeutic approaches for melanoma. Hence, our proposed study is relevant and significant to the health care of Veterans and is in line with the mission of the Department of Veteran Affairs.