MS05.04 Innate Immune Mediators in Lung Cancer

Non-small-cell lung cancer (NSCLC) accounts for about 85% of total lung cancer cases. The major types of NSCLC—squamous cell carcinoma and adenocarcinoma—harbor distinct histopathologies, biomarker expression, genomic alterations, and response to therapy [1,2]. Recent studies have shown that there are also differences in their tumor immune microenvironments [3–6]. Specifically, adenocarcinomas have increased infiltration of tumor-associated macrophages, while squamous lung tumors exhibit an enrichment in tumor-associated neutrophils (TANs) in both mouse and human lung tumors. The two major subtypes of NSCLC are also associated with distinct lineage-specific master regulators: SOX2 is commonly amplified and up-regulated in the vast majority of squamous tumors anddrives the squamous fate, whereas NKX2-1 is highly expressed in adenocarcinoma and governs adenocarcinoma fate [2]. We developed novel genetically engineered mouse models (GEMMs) of squamous lung cancer on the basis of overexpression of the transcription factor Sox2 and loss of the tumor suppressor Lkb1 (SL mice) (Mukhopadhyay et al, Cell Rep, 2014 [7]). SL tumors recapitulated gene expression and immune infiltrate features of human squamous NSCLC, including an enrichment of TANs and a decrease in expression of NKX2-1. Deletion of Nkx2-1in SL mice (SNL) revealed that NKX2-1 suppresses SOX2-driven squamous tumorigenesis by repressing adeno-to-squamous transdifferentiation. We further employed multiple GEMMs to elucidate the role of SOX2 and NKX2-1 in tumor cell fate and TAN recruitment. In Kras-driven adenocarcinomas,mis-expression of Sox2 or loss of Nkx2-1 led to TANrecruitment. SOX2 recruits, whereas NKX2-1 suppresses, TANs at least partly through inverse regulation of the chemokineCxcl5. Tumor-derived CXCL5 is sufficient to recruit TANs. Single cell RNA sequencing (scRNA-seq) revealed that TANs exhibit tumor-promoting features, including production of reactive oxygen species (ROS), and distinct gene expression profiles compared to blood neutrophils (Mollaoglu et al, Immunity, 2018 [8]). Depletion of TANs through LY6G blocking antibodies or CXCR2 inhibitors in SNL mice reduced squamous tumors, suggesting that TANs foster squamous cell fate. Furthermore, TAN depletion coupled with scRNA-seq suggests that TANs regulate distinct aspects of tumor cell fate. Together, these data suggest that lineage-defining transcription factors determine the tumor immune microenvironment, which in turn can impact the nature of the tumor. References 1 Langer, C.J. et al. (2016) Incremental Innovation and Progress in Advanced Squamous Cell Lung Cancer: Current Status and Future Impact of Treatment. J. Thorac. Oncol.11, 2066–2081. 2 Campbell, J.D.et al. (2016) Distinct patterns of somatic genome alterations in lung adenocarcinomas and squamous cell carcinomas. Nat. Genet.48, 607–616. 3 Kargl, J. et al. (2017) Neutrophils dominate the immune cell composition in non-small cell lung cancer. Nat. Commun.8, 14381 4 Nagaraj, A.S. et al. (2017) Cell of Origin Links Histotype Spectrum to Immune Microenvironment Diversity in Non-small-Cell Lung Cancer Driven by Mutant Kras and Loss of Lkb1. Cell Reports 18, 673–684. 5 Xu, C. et al. (2014) Loss of Lkb1 and Pten Leads to Lung Squamous Cell Carcinoma with Elevated PD-L1 Expression. Cancer Cell 25, 590–604. 6 Ferone G., et al. SOX2 Is the Determining Oncogenic Switch in Promoting Lung Squamous Cell Carcinoma from Different Cells of Origin. Cancer Cell. 2016;30(4):519-532. https://doi.org/10.1016/J.CCELL.2016.09.001. 7 Mukhopadhyay, A. et al. (2014) Sox2 Cooperates with Lkb1 Loss in a Mouse Model of Squamous Cell Lung Cancer. Cell Reports 8, 40–49. 8 Mollaoglu, G. et al. (2018) The Lineage-Defining Transcription Factors SOX2 and NKX2-1 Determine Lung Cancer Cell Fate and Shape the Tumor Immune Microenvironment. Immunity 49, 764-779.e9. squamous, neutrophil, SOX2