Regulation of NK cells through extracellular vesicles and microbiota released metabolites in PDAC

NK细胞在肿瘤免疫监视中的关键作用已被广泛接受，但肿瘤依赖性抑制PDAC中NK细胞活性以及由此产生的基于NK细胞的免疫治疗的研究相对较少。在第一个资助期内，我们研究了肿瘤细胞释放的细胞外囊泡的生物发生及其对NK细胞功能的影响。我们确定EV的生物发生依赖于伴侣/NK细胞配体NKp30通过CBP/p300/p53轴的活性。由于P53突变导致该通路频繁功能障碍，导致ev释放具有特定载货量的ev，这些载货量与PDAC （MIF, glypican-1）和因子（肌动蛋白结合蛋白，MyHII）的促肿瘤活性相关，这些活性迄今尚未在PDAC- ev中描述。这些ev抑制NK细胞的细胞毒性，反而促进来自健康供体的NK细胞的衰竭表型。基于这些数据，我们将剖析ev介导的体内机制，该机制使用pan02 -移植模型在免疫抑制和肿瘤促进pdac微环境（TME）中对NK细胞进行重编程。将详细分析肿瘤相关NK细胞（TANK）的表型和活性，并分析已鉴定的ev相关因子作为生物标志物的潜力。预期结果将在人体样本中得到验证。近年来，肠道和肿瘤内细菌在PDAC抗肿瘤免疫应答中的重要作用被报道。初步数据表明，微生物群释放的短链脂肪酸（SCFAs）和细菌囊泡损害NK细胞活性。因此，我们将分析SCFAs和ev在调节NK细胞中的串扰。从长远来看，获得的数据将用于设计能够克服NK细胞抑制并刺激NK细胞活性的治疗性ev，以改善基于NK细胞的PDAC免疫疗法。

The critical role of NK cells in tumor immunosurveillance is widely accepted, but the tumor-dependent suppression of NK cell activity in PDAC and consequently NK cell-based immunotherapies are relatively underexplored. Within the first funding period we investigated the biogenesis of extracellular vesicles released by tumor cells and their impact on NK cell functions. We established that EV biogenesis depends on the activity of the chaperone/NK cell-ligand NKp30 via the CBP/p300/p53 axis. Frequent dysfunction of this pathway due to P53 mutations leads to the release of EVs with specific cargo loading associated with reported pro-tumorigenic activity in PDAC (MIF, glypican-1) and factors (actin-binding proteins, MyHII) that were so far not described in PDAC-EVs. These EVs inhibited NK cell cytotoxicity and instead promoted an exhaustion phenotype in NK cells from healthy donors. Based on this data we will dissect EV-mediated in vivo mechanisms, which reprogram NK cells within the immune suppressive and tumor-promoting PDAC-microenvironment (TME) using a Pan02-transplantation model. The phenotype and the activity of tumor associated NK cells (TANK) will be analyzed in detail and the potential of identified EV-associated factors as biomarkers will be analyzed. Expected results will be validated in human samples. Recently, the crucial role of intestinal and intratumoral bacteria for the anti-tumor immune responses in PDAC was reported. Preliminary own data suggest that short chain fatty acids (SCFAs) and bacterial vesicles released by the microbiota impair NK cell activity. Thus the cross-talk of SCFAs and EVs in regulating NK cells will be analyzed. Perpectively, the data obtained will be used to design therapeutic EVs which are able to overcome NK cell-inhibition and instead stimulate NK cell activity to improve NK cell-based immunotherapies for PDAC.