DataSheet_1_Altered distribution and function of NK-cell subsets lead to impaired tumor surveillance in JAK2V617F myeloproliferative neoplasms.pdf

In cancer, tumor cells and their neoplastic microenvironment can sculpt the immunogenic phenotype of a developing tumor. In this context, natural killer (NK) cells are subtypes of lymphocytes of the innate immune system recognized for their potential to eliminate neoplastic cells, not only through direct cytolytic activity but also by favoring the development of an adaptive antitumor immune response. Even though the protective effect against leukemia due to NK-cell alloreactivity mediated by the absence of the KIR-ligand has already been shown, and some data on the role of NK cells in myeloproliferative neoplasms (MPN) has been explored, their mechanisms of immune escape have not been fully investigated. It is still unclear whether NK cells can affect the biology of BCR-ABL1-negative MPN and which mechanisms are involved in the control of leukemic stem cell expansion. Aiming to investigate the potential contribution of NK cells to the pathogenesis of MPN, we characterized the frequency, receptor expression, maturation profile, and function of NK cells from a conditional Jak2V617F murine transgenic model, which faithfully resembles the main clinical and laboratory characteristics of human polycythemia vera, and MPN patients. Immunophenotypic analysis was performed to characterize NK frequency, their subtypes, and receptor expression in both mutated and wild-type samples. We observed a higher frequency of total NK cells in JAK2V617F mutated MPN and a maturation arrest that resulted in low-numbered mature CD11b+ NK cells and increased immature secretory CD27+ cells in both human and murine mutated samples. In agreement, inhibitory receptors were more expressed in MPN. NK cells from Jak2V617F mice presented a lower potential for proliferation and activation than wild-type NK cells. Colonies generated by murine hematopoietic stem cells (HSC) after mutated or wild-type NK co-culture exposure demonstrated that NK cells from Jak2V617F mice were deficient in regulating differentiation and clonogenic capacity. In conclusion, our findings suggest that NK cells have an immature profile with deficient cytotoxicity that may lead to impaired tumor surveillance in MPN. These data provide a new perspective on the behavior of NK cells in the context of myeloid malignancies and can contribute to the development of new therapeutic strategies, targeting onco-inflammatory pathways that can potentially control transformed HSCs.

在癌症领域，肿瘤细胞及其肿瘤性微环境能够塑造正在发育肿瘤的免疫原性表型。在此背景下，自然杀伤细胞（NK细胞）作为先天免疫系统中的一种淋巴细胞亚型，因其能够消除肿瘤细胞的能力而备受关注，这种能力不仅体现在直接的细胞毒性活性上，还体现在促进适应性抗肿瘤免疫反应的发展上。尽管由于KIR-配体缺失介导的NK细胞同种反应性，已证实其对抗白血病的保护作用，并且已有关于NK细胞在髓增殖性肿瘤（MPN）中作用的某些数据被探索，但它们免疫逃逸的机制尚未得到全面研究。目前尚不清楚NK细胞是否能够影响BCR-ABL1阴性MPN的生物学特性，以及哪些机制参与了白血病干细胞的控制。为了研究NK细胞对MPN发病机制的潜在贡献，我们特征化了来自条件Jak2V617F小鼠转基因模型的NK细胞的频率、受体表达、成熟谱和功能，该模型忠实地反映了人类真性红细胞增多症和MPN患者的主要临床和实验室特征。通过免疫表型分析，对突变型和野生型样本中的NK细胞频率、亚型和受体表达进行了表征。我们观察到在JAK2V617F突变型MPN中总NK细胞的频率较高，并且在人类和小鼠突变型样本中均出现了成熟停滞，导致成熟CD11b+ NK细胞数量减少和未成熟分泌CD27+细胞增加。与此一致，抑制性受体在MPN中表达更为明显。Jak2V617F小鼠来源的NK细胞与野生型NK细胞相比，其增殖和激活潜力较低。经过突变型或野生型NK共培养暴露后，小鼠造血干细胞（HSC）产生的集落表明，Jak2V617F小鼠来源的NK细胞在调节分化和克隆形成能力方面存在缺陷。总之，我们的研究结果提示NK细胞具有不成熟的特征和缺陷的细胞毒性，这可能导致MPN中肿瘤监测功能受损。这些数据为髓系恶性肿瘤中NK细胞的行为提供了新的视角，并有助于开发针对肿瘤炎症途径的新治疗策略，这些策略有可能控制转化型HSC。