Mechanisms of cell death in cutaneous melanoma

项目摘要 皮肤黑色素瘤的发病率正在上升。虽然小分子靶向抑制剂和免疫 检查点抗体增加了晚期皮肤黑色素瘤的长期生存率， 患者仍然没有受益，并且治疗方案与高毒性相关。我们在研究 治疗反应和耐药机制的研究。从我们的研究中，我们的目标是产生前- 延迟/预防获得性耐药性发作同时最大限度减少患者 毒性，以提高患者的生存率和生活质量。多项临床试验来自我们的 工作（NCT 03580382、NCT 02012231、NCT 02683395）。肿瘤免疫原性，定义为免疫原性的能力。 肿瘤本身引发抗肿瘤适应性免疫反应，是肿瘤发生的最重要决定因素之一。 成功的抗癌疗法。肿瘤的免疫原性取决于它的抗原性，由neo- 抗原，以及由损伤相关分子模式（DAMP）释放引发的佐剂效应 在免疫原性细胞死亡（ICD）过程中受到压力或死亡的肿瘤细胞。我们最近 发现了一种信号通路，通过切换凋亡，使DAMP从垂死细胞中有效释放 转化为一种潜在的免疫原性细胞死亡形式，称为细胞凋亡。从机制上讲，半胱天冬酶-3的激活 在细胞凋亡过程中，GSDME-N导致Gasdermin E（GSDME）裂解，产生孔形成GSDME-N片段。 GSDME-N孔允许释放细胞内DAMP，如HMGB 1，DNA和ATP。这种能力 一种将细胞凋亡转变为细胞凋亡的新途径表明，GSDME诱导的细胞凋亡可能是一个关键因素， 癌细胞免疫原性的效应子，并可决定它们对各种抗癌药物的成功应答 治疗支持这一假设，我们的初步数据显示，有效的BRAFi + MEKi诱导的抗- 黑色素瘤细胞中的肿瘤免疫应答至少部分依赖于 GSDME。本申请的目标是定义BRAFi + MEKi调节的潜在机制， GSDME和色素瘤细胞凋亡，并研究GSDME诱导的色素瘤细胞凋亡如何改变GSDME的作用。 免疫检查点抑制剂。黑色素瘤的标准治疗是免疫检查点抑制，特别是 抗PD-1（派姆单抗和纳武单抗）和抗CTLA-4（伊匹单抗）。免疫检查点抑制剂 在一些黑色素瘤患者中有效;然而，许多人没有反应。其他最初有反应的病人， 最终取得进展。该提案旨在利用靶向治疗来优化前期免疫治疗。 检查点抑制剂以及增强抵抗肿瘤的免疫系统。因此，我们的目标是发展 新的治疗策略，将解决在黑色素瘤领域的临床未满足的需求。

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.