Role of exosomal SPHK1 in ovarian cancer progression

项目总结 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免疫疗法 1(PD-L1)和程序性死亡-1(PD-1)，使癌症治疗发生了革命性的变化。然而，与之形成鲜明对比的是 其他恶性肿瘤，如黑色素瘤或肾细胞癌，针对卵巢癌的免疫疗法已经 很大程度上无效。鞘氨醇激酶1(SPHK1)似乎失调了重要的抗肿瘤关键通路 卵巢癌的免疫反应性和几条证据可以解释卵巢癌最小的成功 免疫治疗方法。卵巢癌血液样本中鞘氨醇-1-磷酸(S1P)水平升高， 与正常受试者相比，以前都观察到过。我们还意外地发现SPHK1 卵巢癌细胞中细胞外小泡(EV)蛋白共定位并与之相关。此外，我们还 有数据表明细胞外S1P信号激活PD-L1的表达并抑制细胞毒性T细胞的作用。 鼓励免疫细胞识别和攻击癌细胞是开发免疫疗法的关键 抗卵巢癌，需要详细了解SPHK1包装的EV是如何调节失调的 肿瘤微环境中的免疫反应，对此知之甚少。 这项建议旨在验证中心假设，即肿瘤细胞使用EVS将SPHK1运送到肿瘤 微环境，促进细胞外S1P成熟。后续S1P信令提升 E2F1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 模型通过实现以下三个具体目标：(1)剖析SPHK1的分子机制 胞外囊泡包装及其对胞外S1P成熟的影响。(2)划定 S1P信号促进卵巢癌免疫细胞失活的机制。(三)明确角色定位 SPHK1包装的胞外囊泡在卵巢癌进展中的作用。 我们希望这个项目将阐明S1P和SPHK1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SPHK1或 S1P可作为免疫治疗靶点PD-L1/PD-1蛋白的预测生物标志物。此外，我们 预期SPHK1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.