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

项目总结/摘要 黑色素瘤是美国最致命的皮肤癌，每年约有10万例新发黑色素瘤。 每年确诊的病例。被诊断患有转移性黑色素瘤的患者以前曾患有 极低的5年生存率，但一种称为免疫检查点抑制剂的新型疗法 (ICI)改变了黑色素瘤治疗的前景。ICI疗法在高达50%的 转移性黑色素瘤患者，无论驱动突变如何，但需要努力改善结果 对患者一种这样的策略是将联合收割机靶向治疗，例如在BRAF突变体中使用的那些。 黑色素瘤，用ICI疗法。然而，这种策略受到BRAF突变体中显著毒性的限制。 在20%的肿瘤携带NRAS驱动突变的患者中无效。 初步结果表明，rigosertib，一种新的Ras通路抑制剂，目前在临床试验中， 血液系统恶性肿瘤，可增强抗肿瘤免疫力。我们的初步数据显示， 小鼠黑色素瘤中的rigosertib诱导炎性肿瘤微环境， 富集的总树突状细胞和CD 8+树突状细胞以及CD 45-MHCII+细胞，升高的CD 4+和CD 8+水平 T细胞、B细胞和NK细胞，但PD-1+ CD 4 + T细胞和肿瘤浸润性T细胞的水平降低。 巨噬细胞Rigosertib治疗的黑色素瘤肿瘤表现出CD 4+的频率和密度增加 和CD 8 + T细胞，但在肿瘤微环境中T细胞活化水平非常低。CD8+ 与对照组相比，rigosertib治疗的肿瘤引流淋巴结中的T细胞被强烈激活。 在媒介物处理下活化，表明由肿瘤介导的有效免疫抑制作用。 微环境这些初步数据为使用免疫治疗提供了强有力的治疗基础。 检查点抑制剂（例如，抗PD-1）与rigosertib联合，以增强抗肿瘤免疫力 优化黑色素瘤的治疗这一假设将通过以下方式解决：1）制定一个 微生物反应器系统，用于人NRAS突变型黑素瘤类器官与患者 匹配的白细胞，以评估NRAS突变型黑色素瘤细胞对 与α-PD 1单独治疗相比，rigosertib + α-PD-1联合治疗，以及2）产生 人源化患者来源的异种移植物小鼠模型，以确定NRAS的治疗反应。 突变型黑色素瘤细胞与rigosertib + α-PD-1联合治疗相比， 单独治疗。这些研究将评估一种有前途的新型治疗策略， 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了关键模型， 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.