Investigating concurrent Ras-pathway inhibition to optimize response to anti-PD-1 therapy in NRAS-mutant melanoma

项目摘要/摘要 黑色素瘤是美国最致命的皮肤癌，约有10万名新皮肤癌患者 每年诊断的病例。被诊断为转移性黑色素瘤的患者以前曾经历过 糟糕的5年存活率，但一种名为免疫检查点抑制剂的新疗法 (ICI)已经改变了黑色素瘤治疗的格局。ICI疗法对高达50%的 转移性黑色素瘤患者，无论驱动程序突变，但需要工作来改善结果 对病人来说。一种这样的策略是结合靶向治疗，比如在BRAF突变中使用的那些 黑色素瘤，接受ICI治疗。然而，这种策略受到braf突变体的显著毒性的限制。 在20%的肿瘤患者中存在NRAS驱动程序突变的患者中无效。 初步结果表明，目前正在进行临床试验的新型RAS途径抑制剂rigosertib 恶性血液病，可增强抗肿瘤免疫。我们的初步数据显示，治疗 使用rigosertib的小鼠黑色素瘤诱导炎性肿瘤微环境， 富含总树突状细胞和CD8+树突状细胞以及CD45-MHCII+细胞，提高了CD4+和CD8+的水平 T细胞、B细胞和NK细胞，但PD-1+CD4+T细胞水平下降和肿瘤侵袭 巨噬细胞。经Rigosertib治疗的黑色素瘤患者的CD4+细胞频率和密度增加 和CD8+T细胞，但在肿瘤微环境中T细胞的激活水平很低。然而，CD8+ 与Rigosertib治疗的肿瘤相比，在肿瘤引流的淋巴结中T细胞被强烈激活 在载体治疗下被激活，提示肿瘤介导的强大的免疫抑制效应 微环境。这些初步数据为免疫的使用提供了强有力的治疗基础。 检查点抑制剂(如抗PD-1)与rigosertib联合增强抗肿瘤免疫 并优化黑色素瘤的治疗。这一假设将通过以下方式解决：1)开发一种 用于人NRAS突变型黑色素瘤有机物与患者共培养的微生物反应器系统 匹配白细胞以评估NRAS突变黑色素瘤细胞对 Rigosertib联合α-PD-1治疗与α-PD-1单独治疗相比，2)产生 人源化患者来源的异种移植小鼠模型确定NRAS-1的治疗反应 Rigosertib联合α-PD-1治疗突变黑色素瘤细胞与 单独治疗。这些研究将评估一种前景看好的新治疗策略，具有高度的转化性 与黑色素瘤患者的相关性，同时也为进一步的临床前研究建立关键模型 免疫疗法。

Project Summary/Abstract Melanoma is the most deadly form of skin cancer in the United States, with approximately 100,000 new cases diagnosed annually. Patients diagnosed with metastatic melanoma have previously suffered an abysmal 5-year survival rate, but a novel class of therapeutics termed immune checkpoint inhibitors (ICI) have changed the landscape of melanoma treatment. ICI therapy is effective in up to 50% of metastatic melanoma patients regardless of driver mutation, but work is needed to improve outcomes for patients. One such strategy is to combine targeted therapies, such as those used in BRAF-mutant melanoma, with ICI therapy. However, this strategy is limited by significant toxicity in BRAF-mutant patients and is ineffective in the 20% of patients whose tumors harbor NRAS driver mutations. Preliminary results suggest that rigosertib, a novel Ras-pathway inhibitor currently in clinical trials in hematologic malignancy, may enhance anti-tumor immunity. Our preliminary data show that treatment of melanoma tumors in mice with rigosertib induces an inflammatory tumor microenvironment, with enriched total and CD8+ dendritic cells and CD45-MHCII+ cells, elevated levels of both CD4+ and CD8+ T cells, B cells and NK cells, but decreased levels of PD-1+ CD4+ T cells and tumor-infiltrating macrophages. Rigosertib-treated melanoma tumors exhibit increased frequency and density of CD4+ and CD8+ T cells but very low levels of T cell activation in the tumor microenvironment. However, CD8+ T cells are strongly activated in the tumor-draining lymph nodes of rigosertib-treated tumors compared to activation under vehicle treatment, suggesting a potent immunosuppressive effect mediated by tumor microenvironment. These preliminary data provide a strong therapeutic basis for the use of immune checkpoint inhibitors (e.g., anti-PD-1) in combination with rigosertib to enhance anti-tumor immunity and optimize the treatment of melanoma. This hypothesis will be addressed by: 1) developing a microbioreactor system for the co-culture of human NRAS-mutant melanoma organoids with patient- matched leukocytes to evaluate the treatment response of NRAS-mutant melanoma cells to the combination of rigosertib plus α-PD-1 therapy as compared to α-PD1 alone, and 2) generating humanized patient-derived xenograft mouse models to determine the treatment response of NRAS- mutant melanoma cells to the combination of rigosertib plus α-PD-1 therapy as compared to either therapy alone. These studies will evaluate a promising novel treatment strategy with highly translational relevance to melanoma patients while also establishing critical models for further preclinical studies of immunotherapy.