Department of Lymphoma, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, the Sino-US Center for Lymphoma and Leukemia Research, Tianjin, China.
Panovue Biological Technology Co., Ltd, Beijing, China.
J Immunother Cancer. 2022 Apr;10(4). doi: 10.1136/jitc-2021-004114.
Targeting the PD-1/PD-L1/L2 (programmed cell death protein 1/programmed cell death ligand 1/ligand 2) pathway combined with other immunosuppressive signalings, such as CD73/A2aR (A2a adenosine receptor) adenosine signaling, has emerged as a promising strategy for cancer treatment. The genetic characteristics of these immune checkpoints need to be further investigated in diffuse large B-cell lymphoma (DLBCL).
We performed whole-exome sequencing/targeted deep sequencing to investigate the genetic characteristics of PD-1/PD-L1/L2 and CD73/A2aR. The immunosuppressive effect of these two pathways on the tumor microenvironment was evaluated via RNA sequencing. Single-cell RNA sequencing was further applied to investigate the dysfunctional CD8+ T cells. In addition, multiplex immunofluorescence staining was used to quantitatively assess the expression of dysfunctional CD8 T cells in DLBCL.
SP140 was identified as a novel translocation partner for PD-L1, and a new inversion was detected between PD-L1 and PD-L2, both leading to the upregulation of PD-L1 expression. CD73 genetic mutations did not increase mRNA and protein expression. Patients with genetically altered CD73 tended to have a better overall survival than patients with wild-type CD73. Both PD-1/PD-L1 and CD73/A2aR signaling mediated the immunosuppressive microenvironment in DLBCL. The numbers of CD8 T cells with PD-1 and A2aR expression were positively correlated with the number of dysfunctional CD8 T cells (R=0.974, p0.013). According to the grades of dysfunctional CD8 T cells we defined, 1 dysfunctional CD8 T cells, with either PD-1 or A2aR, were significantly associated with poorer survival than 0 dysfunctional CD8 T cells, with both PD-1 and A2aR; and patients with 2 dysfunctional CD8 T cells showed the worst clinical outcomes.
This study describes the additional genetic basis of PD-L1 overexpression and characterizes certain genetic alterations of CD73/A2aR in DLBCL. The degree of T-cell dysfunction is correlated with clinical outcomes. Strategies that reverse T-cell dysfunction by inhibiting PD-1/PD-L1/L2, particularly in combination with CD73/A2aR, may show potential as effective therapeutic options for DLBCL.
靶向 PD-1/PD-L1/L2（程序性死亡蛋白 1/程序性死亡配体 1/配体 2）通路与其他免疫抑制信号通路（如 CD73/A2aR[A2a 腺苷受体]腺苷信号通路）相结合，已成为癌症治疗的一种有前途的策略。这些免疫检查点的遗传特征需要在弥漫性大 B 细胞淋巴瘤（DLBCL）中进一步研究。
我们进行了全外显子组测序/靶向深度测序，以研究 PD-1/PD-L1/L2 和 CD73/A2aR 的遗传特征。通过 RNA 测序评估了这两条通路对肿瘤微环境的免疫抑制作用。进一步应用单细胞 RNA 测序研究功能失调的 CD8+T 细胞。此外，还使用多重免疫荧光染色定量评估了 DLBCL 中功能失调的 CD8 T 细胞的表达。
鉴定出 SP140 是 PD-L1 的新型易位伙伴，并且在 PD-L1 和 PD-L2 之间检测到新的倒位，这都导致 PD-L1 表达上调。CD73 基因突变并未增加 mRNA 和蛋白表达。具有遗传改变的 CD73 的患者总生存时间长于野生型 CD73 的患者。PD-1/PD-L1 和 CD73/A2aR 信号均介导了 DLBCL 的免疫抑制微环境。表达 PD-1 和 A2aR 的 CD8 T 细胞数量与功能失调的 CD8 T 细胞数量呈正相关（R=0.974，p<0.013）。根据我们定义的功能失调的 CD8 T 细胞的分级，与 0 个具有 PD-1 和 A2aR 的功能失调的 CD8 T 细胞相比，1 个具有 PD-1 或 A2aR 的功能失调的 CD8 T 细胞与更差的生存相关；而具有 2 个功能失调的 CD8 T 细胞的患者则表现出最差的临床结局。
本研究描述了 PD-L1 过表达的额外遗传基础，并描述了 DLBCL 中 CD73/A2aR 的某些遗传改变。T 细胞功能障碍的程度与临床结局相关。通过抑制 PD-1/PD-L1/L2，特别是与 CD73/A2aR 联合抑制 T 细胞功能障碍的策略可能成为 DLBCL 的有效治疗选择。
