Department of Life Sciences, University of Siena, Siena, Italy.
Stem Cell Transplant and Cellular Therapy Unit, University Hospital, Siena, Italy.
Cell Death Dis. 2024 Feb 15;15(2):144. doi: 10.1038/s41419-024-06528-6.
The tumor microenvironment (TME) plays a central role in the pathogenesis of chronic lymphocytic leukemia (CLL), contributing to disease progression and chemoresistance. Leukemic cells shape the TME into a pro-survival and immunosuppressive niche through contact-dependent and contact-independent interactions with the cellular components of the TME. Immune synapse (IS) formation is defective in CLL. Here we asked whether soluble factors released by CLL cells contribute to their protection from cytotoxic T cell (CTL)-mediated killing by interfering with this process. We found that healthy CTLs cultured in media conditioned by leukemic cells from CLL patients or Eμ-TCL1 mice upregulate the exhaustion marker PD-1 and become unable to form functional ISs and kill target cells. These defects were more pronounced when media were conditioned by leukemic cells lacking p66Shc, a proapoptotic adapter whose deficiency has been implicated in disease aggressiveness both in CLL and in the Eμ-TCL1 mouse model. Multiplex ELISA assays showed that leukemic cells from Eμ-TCL1 mice secrete abnormally elevated amounts of CCL22, CCL24, IL-9 and IL-10, which are further upregulated in the absence of p66Shc. Among these, IL-9 and IL-10 were also overexpressed in leukemic cells from CLL patients, where they inversely correlated with residual p66Shc. Using neutralizing antibodies or the recombinant cytokines we show that IL-9, but not IL-10, mediates both the enhancement in PD-1 expression and the suppression of effector functions in healthy CTLs. Our results demonstrate that IL-9 secreted by leukemic cells negatively modulates the anti-tumor immune abilities of CTLs, highlighting a new suppressive mechanism and a novel potential therapeutical target in CLL.
肿瘤微环境 (TME) 在慢性淋巴细胞白血病 (CLL) 的发病机制中起着核心作用，促进疾病进展和化疗耐药。白血病细胞通过与 TME 的细胞成分的接触依赖性和非接触依赖性相互作用，将 TME 塑造成一个有利于生存和免疫抑制的小生境。免疫突触 (IS) 的形成在 CLL 中存在缺陷。在这里，我们询问 CLL 细胞释放的可溶性因子是否通过干扰这一过程来促进其免受细胞毒性 T 细胞 (CTL) 介导的杀伤。我们发现，在来自 CLL 患者或 Eμ-TCL1 小鼠的白血病细胞条件培养基中培养的健康 CTL 上调了衰竭标志物 PD-1，并变得无法形成功能性 IS 并杀伤靶细胞。当缺乏促凋亡接头蛋白 p66Shc 的白血病细胞条件培养基时，这些缺陷更为明显，p66Shc 的缺乏与 CLL 和 Eμ-TCL1 小鼠模型中的疾病侵袭性有关。多重 ELISA 检测显示，Eμ-TCL1 小鼠的白血病细胞异常分泌大量的 CCL22、CCL24、IL-9 和 IL-10，而在缺乏 p66Shc 的情况下，这些细胞因子的分泌进一步上调。其中，IL-9 和 IL-10 也在 CLL 患者的白血病细胞中过度表达，并且与残留的 p66Shc 呈负相关。使用中和抗体或重组细胞因子，我们表明 IL-9 而非 IL-10 介导了健康 CTL 中 PD-1 表达的增强和效应功能的抑制。我们的结果表明，白血病细胞分泌的 IL-9 负调控 CTL 的抗肿瘤免疫能力，突出了一种新的抑制机制和 CLL 中的一个新的潜在治疗靶点。
