GATA2 Regulates Constitutive PD-L1 and PD-L2 Expression in Brain Tumors

• Published in: Scientific reports Vol. 10; no. 1; p. 9027
• Main Authors: Fu, Yujie, Liu, Connor J., Kobayashi, Dale K., Johanns, Tanner M., Bowman-Kirigin, Jay A., Schaettler, Maximilian O., Mao, Diane D., Bender, Diane, Kelley, Diane G., Uppaluri, Ravindra, Bi, Wenya Linda, Dunn, Ian F., Tao, Yu, Luo, Jingqin, Kim, Albert H., Dunn, Gavin P.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03.06.2020; Nature Publishing Group
• Subjects: 13/106; 13/109; 13/31; 14/1; 14/5; 38; 45; 45/77; 59; 631/67/1922; 64; 692/4028/67/580; 96; 96/21; Animals; B7-H1 Antigen - biosynthesis; B7-H1 Antigen - genetics; B7-H1 Antigen - immunology; B7-H1 Antigen - metabolism; Brain cancer; Brain Neoplasms - genetics; Brain Neoplasms - immunology; Brain Neoplasms - metabolism; Brain tumors; CD8-Positive T-Lymphocytes - immunology; Cell Line, Tumor; Clinical trials; Enzyme-linked immunosorbent assay; Flow cytometry; GATA2 Transcription Factor - genetics; GATA2 Transcription Factor - metabolism; Genomics; Glioma; Glioma - genetics; Glioma - immunology; Glioma - metabolism; Humanities and Social Sciences; Humans; Immune checkpoint; Lymphocytes T; Mice; Molecular modelling; multidisciplinary; Neoantigens; PD-1 protein; PD-L1 protein; Programmed Cell Death 1 Ligand 2 Protein - biosynthesis; Programmed Cell Death 1 Ligand 2 Protein - genetics; Programmed Cell Death 1 Ligand 2 Protein - immunology; Programmed Cell Death 1 Ligand 2 Protein - metabolism; Regulatory sequences; Science; Science (multidisciplinary); Tumor cell lines; Tumor Microenvironment; Tumors; γ-Interferon
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-65915-z

Encouraging clinical results using immune checkpoint therapies to target the PD-1 axis in a variety of cancer types have paved the way for new immune therapy trials in brain tumor patients. However, the molecular mechanisms that regulate expression of the PD-1 pathway ligands, PD-L1 and PD-L2, remain poorly understood. To address this, we explored the cell-intrinsic mechanisms of constitutive PD-L1 and PD-L2 expression in brain tumors. PD-L1 and PD-L2 expression was assessed by flow cytometry and qRT-PCR in brain tumor cell lines and patient tumor-derived brain tumor-initiating cells (BTICs). Immunologic effects of PD-L2 overexpression were evaluated by IFN-γ ELISPOT. CD274 and PDCD1LG2 cis -regulatory regions were cloned from genomic DNA and assessed in full or by mutating and/or deleting regulatory elements by luciferase assays. Correlations between clinical responses and PD-L1 and PD-L2 expression status were evaluated in TCGA datasets in LGG and GBM patients. We found that a subset of brain tumor cell lines and BTICs expressed high constitutive levels of PD-L1 and PD-L2 and that PD-L2 overexpression inhibited neoantigen specific T cell IFN-γ production. Characterization of novel cis-regulatory regions in CD274 and PDCD1LG2 lead us to identify that GATA2 is sufficient to drive PD-L1 and PD-L2 expression and is necessary for PD-L2 expression. Importantly, in TCGA datasets, PD-L2 correlated with worse clinical outcomes in glioma patients.. By perturbing GATA2 biology, targeted therapies may be useful to decrease inhibitory effects of PD-L2 in the microenvironment.