Expression regulation and function of PD-1 and PD-L1 in T lymphoma cells

• Published in: Cellular immunology Vol. 366; p. 104397
• Main Authors: Liu, Maria Y., Klement, John D., Langan, Candace J., van Riggelen, Jan, Liu, Kebin
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01-08-2021
• Subjects: Animals; Apoptosis; B7-H1 Antigen - genetics; B7-H1 Antigen - metabolism; Cell Line, Tumor; Cell Proliferation; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Lymphoma, T-Cell - immunology; Mice; Mice, Inbred C57BL; Neoplasms, Experimental; PD-1; PD-L1; Programmed Cell Death 1 Receptor - genetics; Programmed Cell Death 1 Receptor - metabolism; Receptors, Antigen, T-Cell - metabolism; Signal Transduction; T cell receptor; T lymphoma; Tumor Escape; PD-L1; T cell receptor; T lymphoma; PD-1
• ISSN: 0008-8749; 1090-2163
• DOI: 10.1016/j.cellimm.2021.104397

•Human T lymphoma cells express both PD-1 and PD-L1.•TCR signaling activates PD-1 but represses PD-L1 expression in T lymphoma.•PD-L1 promotes T lymphoma growth in vivo.•PD-1 signaling pathways is impaired in vitro but promotes tumor growth in vivo.
T lymphoma cells may constitutively express PD-1 and PD-L1. The relative role of PD-1 and PD-L1 in T lymphoma is incompletely understood. We report here that PD-1+ PDL-1+ human T lymphoma cells exhibit constitutive hyperactivation of the TCR signaling and do not respond to PD-L1-mediated suppression in vitro. Knocking out PD-1 or PD-L1 has no effects on T lymphoma cell apoptosis and proliferation in vitro, but significantly increased tumor-bearing mouse survival. Our findings determine that the constitutively active TCR signaling pathway maintain T lymphoma cell growth in vitro and that both PD-1 and PD-L1 promote T lymphoma growth in vivo.