Role of exosomal SPHK1 in ovarian cancer progression

项目摘要 免疫疗法，包括涉及针对程序性死亡配体的免疫检查点抑制剂的疗法 1（PD-L1）和程序性死亡-1（PD-1），彻底改变了癌症治疗。然而，与之形成鲜明对比的是， 其它恶性肿瘤如黑色素瘤或肾细胞癌、针对卵巢癌的免疫疗法已经被 大部分无效。鞘氨醇激酶1（SPHK 1）似乎对抗肿瘤重要的关键途径失调 卵巢癌的免疫反应性和几条证据可以解释免疫治疗的最小成功率。 免疫疗法。卵巢癌血液样本中鞘氨醇-1-磷酸（S1 P）水平升高， 与正常受试者相比，以前已经观察到。我们还意外地发现SPHK 1 在卵巢癌细胞中与细胞外囊泡（EV）蛋白共定位和相关。此外，我们还 有数据表明细胞外S1 P信号激活PD-L1表达并抑制细胞毒性T细胞作用。 鼓励免疫细胞识别和攻击癌细胞对于开发免疫疗法至关重要 需要详细了解SPHK 1包装的EV如何失调 肿瘤微环境中的免疫反应，对此知之甚少。 该提议试图测试肿瘤细胞利用EV将SPHK 1递送至肿瘤的中心假设 微环境，促进细胞外S1 P成熟。随后的S1 P信号传导促进 E2 F1介导的PD-L1转录，导致免疫抑制和肿瘤增殖。我们将对此进行评估 通过以下三个具体的目标：（1）剖析SPHK 1的分子机制 包装到细胞外囊泡中以及它们对细胞外S1 P成熟的影响。(2)划定 S1 P信号转导促进卵巢癌免疫细胞失活的机制。(3)定义的作用 卵巢癌进展中SPHK 1包装的细胞外囊泡。 我们希望该项目将阐明S1 P和SPHK 1通过以下途径促进免疫逃避的新机制： 高级别浆液性卵巢癌细胞我们还预计，这些研究将确定SPHK 1或 S1 P可以作为免疫治疗靶向PD-L1/PD-1蛋白的预测性生物标志物。而且我们 预期SPHK 1抑制将降低PD-L1水平，并协同PD-1阻断用于免疫治疗 可能是卵巢癌

PROJECT SUMMARY Immunotherapies, including those that involve immune checkpoint inhibitors against programmed death-ligand 1 (PD-L1) and programmed death-1 (PD-1), have revolutionized cancer treatment. However, in stark contrast to other malignancies such as melanoma or renal cell cancer, immunotherapies against ovarian cancer have been largely ineffective. Sphingosine kinase 1 (SPHK1) appears to dysregulate key pathways important for anti-tumor immune responsiveness in ovarian cancer and several lines of evidence may explain the minimal success of an immunotherapy approach. Elevated levels of sphingosine-1-phosphate (S1P) in ovarian cancer blood samples, compared to normal subjects, have been previously observed. We also unexpectedly found that SPHK1 co-localized and associated with extracellular vesicle (EV) proteins in ovarian cancer cells. Furthermore, we also have data suggesting extracellular S1P signaling activates PD-L1 expression and inhibits cytotoxic T cell action. Encouraging immune cells to recognize and attack cancer cells is essential to develop an immunotherapy against ovarian cancer and requires a detailed understanding of how SPHK1-packaged EV dysregulates immune response in the tumor microenvironment, for which little is known. This proposal seeks to test the central hypothesis that tumor cells employ EVs to deliver SPHK1 to the tumor microenvironment, facilitating extracellular S1P maturation. Subsequent S1P signaling promotes E2F1-mediated transcription of PD-L1, causing immune suppression and tumor proliferation. We will assess this model by performing the following three specific aims: (1) Dissect the molecular mechanisms underlying SPHK1 packaging into extracellular vesicles and their effect on extracellular S1P maturation. (2) Delineate the mechanism whereby S1P signaling promotes immune cell inactivation in ovarian cancer. (3) Define the role of SPHK1-packaged extracellular vesicles in ovarian cancer progression. We expect this project will elucidate a novel mechanism by which S1P and SPHK1 promote immune evasion by high-grade serous ovarian cancer cells. We also anticipate that these studies will determine whether SPHK1 or S1P can serve as predictive biomarkers for immunotherapy targets PD-L1/PD-1 proteins. Furthermore, we expect SPHK1 inhibition will lower PD-L1 levels and synergize PD-1 blockade for making immunotherapy possible for ovarian cancer.