Li Ling, Zhao Manzhi, Kiernan Caoimhe H, Castro Eiro Melisa D, van Meurs Marjan, Brouwers-Haspels Inge, Wilmsen Merel E P, Grashof Dwin G B, van de Werken Harmen J G, Hendriks Rudi W, Mueller Yvonne M, Katsikis Peter D
Department of Immunology, Erasmus University Medical Center, Rotterdam, Netherlands.
Cancer Computational Biology Center, Erasmus Medical Center (MC) Cancer Institute, Erasmus University Medical Center, Rotterdam, Netherlands.
Front Immunol. 2023 Sep 12;14:1201415. doi: 10.3389/fimmu.2023.1201415. eCollection 2023.
Cytotoxic CD8+ T cell (CTL) exhaustion is a dysfunctional state of T cells triggered by persistent antigen stimulation, with the characteristics of increased inhibitory receptors, impaired cytokine production and a distinct transcriptional profile. Evidence from immune checkpoint blockade therapy supports that reversing T cell exhaustion is a promising strategy in cancer treatment. Ibrutinib, is a potent inhibitor of BTK, which has been approved for the treatment of chronic lymphocytic leukemia. Previous studies have reported improved function of T cells in ibrutinib long-term treated patients but the mechanism remains unclear. We investigated whether ibrutinib directly acts on CD8+ T cells and reinvigorates exhausted CTLs.
We used an established CTL exhaustion system to examine whether ibrutinib can directly ameliorate T cell exhaustion. Changes in inhibitory receptors, transcription factors, cytokine production and killing capacity of ibrutinib-treated exhausted CTLs were detected by flow cytometry. RNA-seq was performed to study transcriptional changes in these cells. Btk deficient mice were used to confirm that the effect of ibrutinib was independent of BTK expression.
We found that ibrutinib reduced exhaustion-related features of CTLs in an CTL exhaustion system. These changes included decreased inhibitory receptor expression, enhanced cytokine production, and downregulation of the transcription factor TOX with upregulation of TCF1. RNA-seq further confirmed that ibrutinib directly reduced the exhaustion-related transcriptional profile of these cells. Importantly, using btk deficient mice we showed the effect of ibrutinib was independent of BTK expression, and therefore mediated by one of its other targets.
Our study demonstrates that ibrutinib directly ameliorates CTL exhaustion, and provides evidence for its synergistic use with cancer immunotherapy.
细胞毒性CD8 + T细胞（CTL）耗竭是由持续抗原刺激引发的T细胞功能失调状态，其特征为抑制性受体增加、细胞因子产生受损以及独特的转录谱。免疫检查点阻断疗法的证据支持逆转T细胞耗竭是癌症治疗中一种有前景的策略。依鲁替尼是一种有效的BTK抑制剂，已被批准用于治疗慢性淋巴细胞白血病。先前的研究报道了依鲁替尼长期治疗患者中T细胞功能有所改善，但机制尚不清楚。我们研究了依鲁替尼是否直接作用于CD8 + T细胞并恢复耗竭的CTL活力。
我们使用已建立的CTL耗竭系统来检查依鲁替尼是否能直接改善T细胞耗竭。通过流式细胞术检测依鲁替尼处理的耗竭CTL中抑制性受体、转录因子、细胞因子产生和杀伤能力的变化。进行RNA测序以研究这些细胞中的转录变化。使用Btk缺陷小鼠来确认依鲁替尼的作用独立于BTK表达。
我们发现在CTL耗竭系统中依鲁替尼减少了CTL的耗竭相关特征。这些变化包括抑制性受体表达降低、细胞因子产生增强以及转录因子TOX下调和TCF1上调。RNA测序进一步证实依鲁替尼直接降低了这些细胞的耗竭相关转录谱。重要的是，使用Btk缺陷小鼠我们表明依鲁替尼的作用独立于BTK表达，因此是由其其他靶点之一介导的。
我们的研究表明依鲁替尼直接改善CTL耗竭，并为其与癌症免疫疗法联合使用提供了证据。
