Mechanisms of cell death in cutaneous melanoma

项目总结 皮肤黑色素瘤的发病率正在上升。而小分子靶向抑制物和免疫 检查点抗体增加了晚期皮肤黑色素瘤的长期存活率 患者仍然没有受益，而且治疗方案具有很高的毒性。我们正在研究决定因素 黑色素瘤的治疗反应和耐药机制。从我们的研究中，我们的目标是产生预 延缓/预防获得性耐药性的新组合的临床数据，同时将患者降至最低 毒副作用，以提高患者的生存和生活质量。多项临床试验是从我们的 工作(NCT03580382、NCT02012231、NCT02683395)。肿瘤免疫原性，定义为肿瘤细胞的免疫原性 肿瘤本身能够触发抗肿瘤的获得性免疫反应，是最重要的决定因素之一 成功的抗癌治疗。肿瘤的免疫原性取决于它的抗原性，这种抗原性是由neo- 抗原，以及由损伤相关分子模式(DAMP)释放所触发的佐剂效应 在一种称为免疫原性细胞死亡(ICD)的过程中，肿瘤细胞受到应激或死亡。我们最近 发现了一种信号通路，可以通过切换细胞凋亡来有效地释放濒死细胞中的湿气 转化为一种潜在的免疫原性细胞死亡形式，称为下垂。从机制上讲，caspase-3的激活 在细胞凋亡过程中导致Gasdermin E(GSDME)的裂解，产生一个成孔的GSDME-N片段。 GSDME-N孔允许释放细胞内的潮湿物质，如HMGB1、DNA和ATP。这样做的能力 细胞凋亡转化为下垂的新途径提示GSDME诱导的下垂可能是一个关键 肿瘤细胞免疫原性的效应因子，并可能决定其对多种抗癌药物的成功反应 治疗。支持这一假设，我们的初步数据显示，高效的BRAFi Meki诱导的抗- 黑色素瘤细胞的肿瘤免疫反应至少部分依赖于 天哪。此应用程序的目标是定义BRAFi Meki监管的潜在机制 目的：探讨GSDME与黑色素瘤上睑下垂的关系，以及GSDME诱导的上睑下垂是如何改变的。 免疫检查点抑制剂。治疗黑色素瘤的标准是免疫检查点抑制，特别是 抗PD-1(pembrolizumab和nivolumab)和抗CTLA-4(Ipilimumab)。免疫检查点抑制剂是 对一些黑色素瘤患者有效；然而，许多人没有反应。其他最初有反应的患者， 最终取得进步。这项建议旨在利用靶向治疗来优化前期免疫。 检查点抑制剂以及激活耐药肿瘤的免疫系统。因此，我们的目标是发展 新的治疗策略将解决黑色素瘤领域临床上未得到满足的需求。

PROJECT SUMMARY The incidence of cutaneous melanoma is rising. While small molecule targeted inhibitors and immune checkpoint antibodies have increased long-term survival in advanced-stage cutaneous melanoma, many patients still do not benefit and regimens are associated with high toxicity. We are studying the determinants of treatment response and mechanisms of resistance in melanoma. From our studies, we aim to generate pre- clinical data for new combinations that delay/prevent the onset of acquired resistance while minimizing patient toxicities in order to improve patient survival and quality of life. Multiple clinical trials have emanated from our work (NCT03580382, NCT02012231, NCT02683395). Tumor immunogenicity, defined as the ability of the tumor itself to trigger an anti-tumor adaptive immune response, is one of the most important determinants of successful anti-cancer therapy. The immunogenicity of a tumor depends on its antigenicity, conferred by neo- antigens, and also by adjuvant effects triggered by damage-associated molecular patterns (DAMPs) released from stressed or dying tumor cells during a process called immunogenic cell death (ICD). We recently discovered a signaling pathway that allows efficient release of DAMPs from dying cells by switching apoptosis into a potentially immunogenic form of cell death called pyroptosis. Mechanistically, activation of caspase-3 during apoptosis leads to cleavage of gasdermin E (GSDME), generating a pore-forming GSDME-N fragment. GSDME-N pores allow release of intracellular DAMPs such as HMGB1, DNA, and ATP. The ability of this novel pathway to switch apoptosis into pyroptosis suggests that GSDME-induced pyroptosis is likely a key effector of cancer cell immunogenicity and may determine their successful response to various anti-cancer therapies. Supporting this hypothesis, our preliminary data revealed that efficient BRAFi + MEKi-induced anti- tumor immune responses in melanoma cells are dependent, at least in part, on the pyroptotic activity of GSDME. The goals of this application are to define mechanisms underlying BRAFi + MEKi regulation of GSDME and pyroptosis in melanoma and to investigate how GSDME-induced pyroptosis alters the effects of immune checkpoint inhibitors. The standard of care for melanomas is immune checkpoint inhibition, specifically anti-PD-1 (pembrolizumab and nivolumab) and anti-CTLA-4 (ipilimumab). Immune checkpoint inhibitors are efficacious in some melanoma patients; however, many do not respond. Other patients who initially respond, ultimately progress. This proposal is designed to utilize targeted therapies to optimize up-front immune checkpoint inhibitors as well as invigorating the immune system in resistant tumors. Thus, we aim to develop new therapeutic strategies that will address clinical unmet needs in the melanoma field.