Lkb1 通过促进 Treg 细胞功能和免疫逃逸加重弥漫性大 B 细胞淋巴瘤。

Lkb1 aggravates diffuse large B-cell lymphoma by promoting the function of Treg cells and immune escape.

机构信息

Department of Hematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, People's Republic of China.

School of Medicine, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China.

出版信息

J Transl Med. 2022 Aug 19;20(1):378. doi: 10.1186/s12967-022-03588-0.

DOI:10.1186/s12967-022-03588-0

PMID:35986288

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9392310/

Abstract

BACKGROUND

Regulatory T cells (Tregs) induce immune responses and may contribute to immune escape in tumors. Accumulation of Tregs in tumors represents a critical barrier to anti-tumor immunity and immunotherapy. However, conflicting results describing the role of Tregs in lymphoma warrant further investigation. The precise features and mechanisms underlying the alteration in Tregs in diffuse large B-cell lymphoma (DLBCL) are not well understood yet. In this study, we analyzed the mechanism underlying the observed alterations in Tregs in DLBCL and examined the effect of Lkb1 expression on the immunosuppressive function of human Tregs.

METHODS

Flow cytometry and immunofluorescence were used to analyze the proportion of Tregs and effector Tregs in the peripheral blood and lymph nodes of patients with DLBCL and control group. In vitro culture assays were used to analyze the immunosuppressive function of Tregs in the two groups. Transcriptome sequencing was performed to analyze the differentially expressed genes in the two groups, and the transcription level and protein expression of Lkb1 in the two groups were detected using RT-PCR and WES microprotein technology. Lentiviral vectors were constructed to explore the functional changes of Tregs with stable upregulation and downregulation of Lkb1. Finally, a humanized murine lymphoma model was established to study the function of Lkb1 in Tregs in the pathogenesis of DLBCL.

RESULTS

The number of Tregs was found to be dramatically increased in peripheral blood and tumor tissue in DLBCL patients compared with that in healthy controls, and decreased after treatment. Tregs from DLBCL patients exhibited multiple enhanced functions, including increased inhibition of CD8cytotoxic T cells (CTL) against tumor cells, enhanced suppression of CD8CTL secretion of granular enzyme, and suppression of CD8CTL degranulation. Lkb1 was found to be upregulated in Tregs of DLBCL patients. Furthermore, Lkb1 contributes to Treg immunosuppressive function in DLBCL by regulating the mevalonate pathway. Finally, deletion of Lkb1 in Tregs suppressed tumor growth and promoted anti-tumor immunity in a DLBCL murine model.

CONCLUSIONS

These findings confirmed that Lkb1-regulated Tregs are critical for immune escape in DLBCL, which emphasizes that Lkb1 is a potential target for the immunotherapy of DLBCL.

摘要

背景

调节性 T 细胞（Tregs）可诱导免疫应答，并可能有助于肿瘤中的免疫逃逸。Tregs 在肿瘤中的积累是抗肿瘤免疫和免疫治疗的一个关键障碍。然而，描述 Tregs 在淋巴瘤中的作用的结果相互矛盾，需要进一步研究。Tregs 在弥漫性大 B 细胞淋巴瘤（DLBCL）中变化的确切特征和机制尚不清楚。在这项研究中，我们分析了观察到的 DLBCL 中 Tregs 变化的机制，并研究了 Lkb1 表达对人 Tregs 免疫抑制功能的影响。

方法

流式细胞术和免疫荧光法用于分析 DLBCL 患者和对照组外周血和淋巴结中 Tregs 和效应 Tregs 的比例。体外培养实验用于分析两组 Tregs 的免疫抑制功能。进行转录组测序以分析两组中差异表达的基因，并使用 RT-PCR 和 WES 微蛋白技术检测两组中 Lkb1 的转录水平和蛋白表达。构建慢病毒载体，探索 Lkb1 稳定上调和下调对 Tregs 功能变化的影响。最后，建立人源化淋巴瘤模型，研究 Lkb1 在 Tregs 中对 DLBCL 发病机制的作用。

结果

与健康对照组相比，DLBCL 患者外周血和肿瘤组织中的 Tregs 数量明显增加，治疗后减少。来自 DLBCL 患者的 Tregs 表现出多种增强的功能，包括增加抑制 CD8 细胞毒性 T 细胞（CTL）对肿瘤细胞的作用、增强抑制 CD8CTL 分泌颗粒酶以及抑制 CD8CTL 脱颗粒。Lkb1 在 DLBCL 患者的 Tregs 中上调。此外，Lkb1 通过调节甲羟戊酸途径促进 DLBCL 中 Treg 的免疫抑制功能。最后，在 DLBCL 小鼠模型中删除 Tregs 中的 Lkb1 可抑制肿瘤生长并促进抗肿瘤免疫。