Li Xiang, Dong Liang, Liu Jiejie, Wang Chunmeng, Zhang Yan, Mei Qian, Han Weidong, Xie Ping, Nie Jing
Department of Cell Biology, The Municipal Key Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, China.
Department of Bio-therapeutic, The First Medical Center, Chinese PLA General Hospital, Beijing, China.
Front Cell Dev Biol. 2021 Mar 15;9:647713. doi: 10.3389/fcell.2021.647713. eCollection 2021.
CD4 T cells play multiple roles in controlling tumor growth and increasing IFN-γ T-helper 1 cell population could promote cell-mediated anti-tumor immune response. We have previously showed that low-dose DNA demethylating agent decitabine therapy promotes CD3 T-cell proliferation and cytotoxicity; however, direct regulation of purified CD4 T cells and the underlying mechanisms remain unclear.
The effects of low-dose decitabine on sorted CD4 T cells were detected both and . The activation, proliferation, intracellular cytokine production and cytolysis activity of CD4 T cells were analyzed by FACS and DELFIA time-resolved fluorescence assays. ubiquitination assay was performed to assess protein degradation. Moreover, phosphor-p65 and IκBα levels were detected in sorted CD4 T cells from solid tumor patients with decitabine-based therapy.
Low-dose decitabine treatment promoted the proliferation and activation of sorted CD4 T cells, with increased frequency of IFN-γ Th1 subset and enhanced cytolytic activity and . NF-κB inhibitor, BAY 11-7082, suppressed decitabine-induced CD4 T cell proliferation and IFN-γ production. In terms of mechanism, low-dose decitabine augmented the expression of E3 ligase β-TrCP, promoted the ubiquitination and degradation of IκBα and resulted in NF-κB activation. Notably, we observed that low-dose decitabine treatment induced NF-κB activation in CD4 T cells from patients with a response to decitabine-primed chemotherapy rather than those without a response.
These data suggest that low-dose decitabine potentiates CD4 T cell anti-tumor immunity through enhancing IκBα degradation and therefore NF-κB activation and IFN-γ production.
CD4 T细胞在控制肿瘤生长中发挥多种作用，增加干扰素-γ辅助性T1细胞群体可促进细胞介导的抗肿瘤免疫反应。我们之前已表明，低剂量DNA去甲基化药物地西他滨治疗可促进CD3 T细胞增殖和细胞毒性；然而，纯化CD4 T细胞的直接调控及其潜在机制仍不清楚。
检测低剂量地西他滨对分选的CD4 T细胞的影响。通过流式细胞术和时间分辨荧光免疫分析（DELFIA）分析CD4 T细胞的激活、增殖、细胞内细胞因子产生和细胞溶解活性。进行泛素化分析以评估蛋白质降解。此外，在接受基于地西他滨治疗的实体瘤患者分选的CD4 T细胞中检测磷酸化p65和IκBα水平。
低剂量地西他滨治疗促进了分选的CD4 T细胞的增殖和激活，增加了干扰素-γ Th1亚群的频率并增强了细胞溶解活性。NF-κB抑制剂BAY 11-7082抑制了地西他滨诱导的CD4 T细胞增殖和干扰素-γ产生。在机制方面，低剂量地西他滨增加了E3连接酶β-TrCP的表达，促进了IκBα的泛素化和降解并导致NF-κB激活。值得注意的是，我们观察到低剂量地西他滨治疗在对基于地西他滨的化疗有反应的患者的CD4 T细胞中诱导NF-κB激活，而在无反应的患者中则未诱导。
这些数据表明，低剂量地西他滨通过增强IκBα降解从而激活NF-κB和产生干扰素-γ来增强CD4 T细胞抗肿瘤免疫力。
