Genetic defects of the IRF1-mediated major histocompatibility complex class I antigen presentation pathway occur prevalently in the JAK2 gene in non-small cell lung cancer
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Tao Shen1,2, Zhengming Chen1,3, Zhizhuang Joe Zhao4 and Jie Wu1,2,4
1Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, USA
2Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
3Division of Biostatistics and Epidemiology, Department of Healthcare Policy and Research, Weill Cornell Medicine, New York, New York, USA
4Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
Jie Wu, email: email@example.com
Keywords: NSCLC, JAK2, IRF1, Interferon-γ, antigen presentation
Received: December 20, 2016 Accepted: April 06, 2017 Published: May 08, 2017
Recognition of major histocompatibility complex (MHC) class I antigens on tumor cells by cytotoxic T cells is involved in T cell-mediated tumor immune surveillance and immune checkpoint therapy. The interferon-γ (IFNγ)-IRF1 signaling pathway regulates MHC class I antigen presentation. To examine genetic defects of the IFNγ-IRF1 pathway in non-small cell lung cancer (NSCLC), we analyzed The Cancer Genome Atlas (TCGA) lung adenocarcinoma (LuAd) and lung squamous cell carcinoma (LuSc) data. Loss-of-function (LOF) genetic alterations of the IFNγ-IRF1 pathway genes (IFNGR1, IFNGR2, JAK1, JAK2, STAT1, IRF1) were found in 64 (6.3%) of 1,016 patients. These genetic defects occur prevalently in JAK2 (33 cases) and often through deletions (29 cases) of chromosome 9p24.1. JAK2 deletions were frequently, but not always, associated with deletions of PD-L1 gene (CD274), PD-L2 gene (PDCD1LG2), PTPRD, and CDKN2A/CDKN2B at the chromosome 9p24.1-9p21.3 region. IRF1 expression was correlated with immune cytolytic activity markers GZMA and PRF1 in NSCLC. IFNγ induced IRF1 expression and cell surface HLA-A/HLA-B/HLA-C (HLA-ABC) in A549, H661, H292, and H2172 cells that contained the wildtype JAK2, but not in H1573 and H1623 cells that were JAK2 defective. Deletion of JAK2 or inhibition of the JAK2 kinase activity resulted in loss of IFNγ-induced IRF1 and cell surface HLA-ABC in JAK2 wildtype NSCLC cells, whereas expression of exogenous JAK2 in H1573 cells restored the IFNγ responses. These findings show that JAK2 deficiency is the major mechanism of genetic defects of the IFNγ-IRF1 pathway in NSCLC and reveal a previously unrecognized significance of chromosome 9p deletion in NSCLC.
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