Tyrosine kinase pathways modulate tumor susceptibility to natural killer cells
Roberto Bellucci, Hong-Nam Nguyen, Allison Martin, Stefan Heinrichs, Anna C. Schinzel, William C. Hahn, Jerome Ritz
Roberto Bellucci, Hong-Nam Nguyen, Allison Martin, Stefan Heinrichs, Anna C. Schinzel, William C. Hahn, Jerome Ritz
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Research Article Oncology

Tyrosine kinase pathways modulate tumor susceptibility to natural killer cells

Abstract

Natural killer (NK) cells are primary effectors of innate immunity directed against transformed tumor cells. In response, tumor cells have developed mechanisms to evade NK cell–mediated lysis through molecular mechanisms that are not well understood. In the present study, we used a lentiviral shRNA library targeting more than 1,000 human genes to identify 83 genes that promote target cell resistance to human NK cell–mediated killing. Many of the genes identified in this genetic screen belong to common signaling pathways; however, none of them have previously been known to modulate susceptibility of human tumor cells to immunologic destruction. Gene silencing of two members of the JAK family (JAK1 and JAK2) increased the susceptibility of a variety of tumor cell types to NK-mediated lysis and induced increased secretion of IFN-γ by NK cells. Treatment of tumor cells with JAK inhibitors also increased susceptibility to NK cell activity. These findings may have important clinical implications and suggest that small molecule inhibitors of tyrosine kinases being developed as therapeutic antitumor agents may also have significant immunologic effects in vivo.

Authors

Roberto Bellucci, Hong-Nam Nguyen, Allison Martin, Stefan Heinrichs, Anna C. Schinzel, William C. Hahn, Jerome Ritz

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Figure 4

Analysis of IM-9 cells expressing shRNAs targeting JAK1.

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Analysis of IM-9 cells expressing shRNAs targeting JAK1. (A) Western blo...
(A) Western blot analysis of IM-9 target cells with stable incorporation of different sh­RNAs targeting JAK1 (Jak1-1, Jak1-2, and Jak1-3), irrelevant shRNAs (shCTRL-2 and shCTRL-3), and parental IM-9. (B) RNAs from parental IM-9 and each IM-9 with stable expression of JAK1, JAK2, and control shRNAs were also evaluated for JAK1 gene expression. Data represent the relative expression of JAK1 in parental IM-9 cells, 2 controls (shCTRL-2 and shCTRL-3), IM-9 cells expressing 3 shRNAs targeting JAK1 (Jak1-1, Jak1-2, and Jak1-3), and IM-9 cells expressing 2 shRNAs targeting JAK2 (Jak2-3 and Jak2-4). (C) IFN-γ secretion by NKL or NK-92 effector cells incubated with stable IM-9-JAK1-kockdown cells at a 1:1 E/T ratio for 12 hours. Data represent the median of 6 independent experiments with each target cell tested in duplicate. (D) Specific lysis of stable IM-9-JAK1-knockdown target cells incubated with NKL or NK-92 effector cells. Percent lysis was determined in a 4-hour chromium release assay for samples incubated at different E/T ratios. Data represent percent killing in 3 different experiments tested in triplicate. (E) Percent apoptosis induced by NKL or NK-92 effector cells incubated at a 1:1 E/T ratio for 12 hours with stable IM-9-JAK1-knockdown cells. Cells were stained with a PE-conjugated NKG2A antibody, and the analysis of apoptotic cells was performed on the gated target cells (NKG2A negative). Data represent the mean percent apoptosis induction in 4 independent experiments tested in duplicate. The level of spontaneous apoptosis in IM-9-JAK1-knockdown was subtracted in every experiment.