Author of

• 20156

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  P1.07 - Immunology and Immunotherapy (ID 693)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Immunology and Immunotherapy
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/16/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 22675

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    P1.07-007 - Interleukin-17A Promotes Lung Tumor Progression Through Neutrophil Attraction to Tumor Sites and Mediating Resistance to PD-1 Blockade.   (ID 8342)

    09:30 - 09:30  |  Author(s): S. Koyama
    • Abstract

    Background:
    Proinflammatory cytokine Interleukin (IL)-17A (IL-17A) is the prototypical member of the IL-17 family of pro-inflammatory cytokines. It is produced by Th17 cells, CD8 T cells, γδT cells, and Natural Killer (NK) cells in the tumor microenvironment. The inflammatory milieu can contribute to lung cancer growth by further production of tumor promoting cytokines, reduction in cytotoxic T cells, and development of myeloid derived suppressor cells. IL-17A and its receptors are expressed across different tumor types; however, their exact role in tumor development, progression, and response to therapeutic regimens is unclear. IL-17A is overexpressed in a subset of patients with lung cancer. We hypothesized that IL-17A promotes a pro-tumorigenic inflammatory phenotype, and inhibits anti-tumor immune responses.
    
    Method:
    IL-17A is expressed at high levels in a subset of lung cancers. Interestingly, we observed that IL-17A could not be detected in Bronchoalveolar lavage fluids (BALFs) from immunocompetent mouse lung cancer models. To characterize the role of IL-17A in Kras mutant lung tumors, we developed a mouse model of chronic inflammation that more closely resembles human KRAS mutant lung cancer through expressing IL-17A constitutively in the lung epithelium and then introducing this allele into lox-stop-lox Kras G12D mutant mice. We performed immune phenotyping of mouse lungs, survival analysis, and treatment studies with antibodies either blocking PD-1 or IL6, or depleting neutrophils. To support preclinical findings, we analyzed human gene expression datasets and immune profiled patient lung tumors.
    
    Result:
    Tumors in IL-17:Kras G12D[]mice grew more rapidly, resulting in a significantly shorter survival as compared to Kras G12D. IL-6, G-CSF, MFG-E8, and CXCL1 were increased in the lungs of IL17:Kras mice. Time course analysis revealed that tumor-associated neutrophils were significantly elevated, and lymphocyte recruitment was significantly reduced in IL17:Kras G12D mice as compared to Kras G12D. In therapeutic studies PD-1 blockade was not effective in treating IL-17:Kras G12D tumors. In contrast, blocking IL-6 or depleting neutrophils with an anti-Ly-6G antibody in the IL17:Kras G12D tumors resulted in a clinical response associated with T cell activation. In tumors from lung cancer patients with KRAS mutation we found a correlation among higher levels of IL-17A and the colony stimulating factor (CSF3), and a significant correlation among high neutrophil and lower T cell numbers.
    
    Conclusion:
    Here we show that an increase in a single cytokine, IL-17A, without additional mutations, can promote lung cancer growth by promoting inflammation, which contributes to resistance to PD-1 blockade and sensitizes tumors to cytokine/neutrophil depletion.