Chronic Obstructive Pulmonary Disease Alters Immune Cell Composition and Immune Checkpoint Inhibitor Efficacy in Non-Small Cell Lung Cancer.

RATIONALE: Chronic obstructive pulmonary disease (COPD) and non-small cell lung cancer (NSCLC) are interrelated diseases with substantial mortality, and the pathogenesis of both involves aberrant immune functioning. OBJECTIVES: To profile immune cell composition and function in patients with NSCLC and describe the effects of COPD on lung and tumor microenvironments. METHODS: We profiled resected lung and tumor tissue using flow cytometry and T-cell receptor sequencing in patients with and without COPD from a prospective cohort of patients undergoing resection of NSCLC. A murine cigarette smoke exposure model was used to evaluate the effect on pulmonary immune populations. A separate retrospective cohort of patients who received immune checkpoint inhibitors (ICIs) was analyzed, and their survival was quantified. MEASUREMENTS AND MAIN RESULTS: We observed an increased number of IFN-γ-producing CD8+ and CD4+ (T-helper cell type 1 [Th1]) lymphocytes in the lungs of patients with COPD. In both humans and mice, increased Th17 content was seen with smoke exposure, but was not associated with the development or severity of COPD. COPD-affected lung tissue displayed increased Th1 differentiation that was recapitulated in the matching tumor sample. PD-1 (programmed cell death protein 1) expression was increased in tumors of patients with COPD, and the presence of COPD was associated with progression-free survival in patients treated with ICIs. CONCLUSIONS: In patients with COPD, Th1 cell populations were expanded in both lung and tumor microenvironments, and the presence of COPD was associated with longer progression-free intervals in patients treated with ICIs. This has implications for understanding the immune mediators of COPD and developing novel therapies for NSCLC.

Insulin receptor substrate-1 deficiency drives a proinflammatory phenotype in KRAS mutant lung adenocarcinoma.

Insulin receptor substrate-1 (IRS-1) is a signaling adaptor protein that interfaces with many pathways activated in lung cancer. It has been assumed that IRS-1 promotes tumor growth through its ability to activate PI3K signaling downstream of the insulin-like growth factor receptor. Surprisingly, tumors with reduced IRS-1 staining in a human lung adenocarcinoma tissue microarray displayed a significant survival disadvantage, especially within the Kirsten rat sarcoma viral oncogene homolog (KRAS) mutant subgroup. Accordingly, adenoviral Cre recombinase (AdCre)-treated LSL-Kras/Irs-1(fl/fl) (Kras/Irs-1(-/-)) mice displayed increased tumor burden and mortality compared with controls. Mechanistically, IRS-1 deficiency promotes Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling via the IL-22 receptor, resulting in enhanced tumor-promoting inflammation. Treatment of Kras/Irs-1(+/+) and Kras/Irs-1(-/-) mice with JAK inhibitors significantly reduced tumor burden, most notably in the IRS-1-deficient group.

Lung Cancer Subtypes Generate Unique Immune Responses.

Lung cancer, the leading cause of cancer-related deaths worldwide, is a heterogeneous disease comprising multiple histologic subtypes that harbor disparate mutational profiles. Immune-based therapies have shown initial promise in the treatment of lung cancer patients but are limited by low overall response rates. We sought to determine whether the host immune response to lung cancer is dictated, at least in part, by histologic and genetic differences, because such correlations would have important clinical ramifications. Using mouse models of lung cancer, we show that small cell lung cancer (SCLC) and lung adenocarcinoma (ADCA) exhibit unique immune cell composition of the tumor microenvironment. The total leukocyte content was markedly reduced in SCLC compared with lung ADCA, which was validated in human lung cancer specimens. We further identified key differences in immune cell content using three models of lung ADCA driven by mutations in Kras, p53, and Egfr Although Egfr-mutant cancers displayed robust myeloid cell recruitment, they failed to mount a CD8+ immune response. In contrast, Kras-mutant tumors displayed significant expansion of multiple immune cell types, including CD8+ cells, regulatory T cells, IL-17A-producing lymphocytes, and myeloid cells. A human tissue microarray annotated for KRAS and EGFR mutations validated the finding of reduced CD8+ content in human lung ADCA. Taken together, these findings establish a strong foundational knowledge of the immune cell contexture of lung ADCA and SCLC and suggest that molecular and histological traits shape the host immune response to cancer.

Neutrophils dominate the immune cell composition in non-small cell lung cancer.

The response rate to immune checkpoint inhibitor therapy for non-small-cell lung cancer (NSCLC) is just 20%. To improve this figure, several early phase clinical trials combining novel immunotherapeutics with immune checkpoint blockade have been initiated. Unfortunately, these trials have been designed without a strong foundational knowledge of the immune landscape present in NSCLC. Here, we use a flow cytometry panel capable of measuring 51 immune cell populations to comprehensively identify the immune cell composition and function in NSCLC. The results show that the immune cell composition is fundamentally different in lung adenocarcinoma as compared with lung squamous cell carcinoma, and that neutrophils are the most prevalent immune cell type. Using T-cell receptor-ß sequencing and tumour reactivity assays, we predict that tumour reactive T cells are frequently present in NSCLC. These results should help to guide the design of clinical trials and the direction of future research in this area.

Neutrophil elastase promotes myofibroblast differentiation in lung fibrosis.

IPF is a progressive lung disorder characterized by fibroblast proliferation and myofibroblast differentiation. Although neutrophil accumulation within IPF lungs has been negatively correlated with outcomes, the role played by neutrophils in lung fibrosis remains poorly understood. We have demonstrated previously that NE promotes lung cancer cell proliferation and hypothesized that it may have a similar effect on fibroblasts. In the current study, we show that NE(-/-) mice are protected from asbestos-induced lung fibrosis. NE(-/-) mice displayed reduced fibroblast and myofibroblast content when compared with controls. NE directly both lung fibroblast proliferation and myofibroblast differentiation in vitro, as evidenced by proliferation assays, collagen gel contractility assays, and αSMA induction. Furthermore, αSMA induction occurs in a TGF-ß-independent fashion. Treatment of asbestos-recipient mice with ONO-5046, a synthetic NE antagonist, reduced hydroxyproline content. Thus, the current study points to a key role for neutrophils and NE in the progression of lung fibrosis. Lastly, the study lends rationale to use of NE-inhibitory approaches as a novel therapeutic strategy for patients with lung fibrosis.

Insulin receptor substrate regulation of phosphoinositide 3-kinase.

Insulin receptor substrates (IRS) serve as downstream messengers from activated cell surface receptors to numerous signaling pathway cascades. One of these pathways, phosphoinositide 3-kinase (PI3K), frequently displays aberrant function in the setting of cancer. IRS proteins are capable of both regulating and activating PI3K, depending on the cell of origin. As such, both prohost and protumor functions have been described for IRS proteins in human cancers. IRS proteins may eventually serve as biomarkers of PI3K activity, and serve a much-needed role as a guide to using targeted pathway therapy. Additionally, IRS-1 could be indirectly targeted in lung cancer, by inhibiting neutrophil elastase, which functions to degrade IRS-1 in lung tumor cells, thereby generating PI3K hyperactivity.

Neutrophil elastase-mediated degradation of IRS-1 accelerates lung tumor growth.

Lung cancer is the leading cause of cancer death worldwide. Recent data suggest that tumor-associated inflammatory cells may modify lung tumor growth and invasiveness. To determine the role of neutrophil elastase (encoded by Elane) on tumor progression, we used the loxP-Stop-loxP K-ras(G12D) (LSL-K-ras) model of mouse lung adenocarcinoma to generate LSL-K-ras-Elane(-/-) mice. Tumor burden was markedly reduced in LSL-K-ras-Elane(-/-) mice at all time points after induction of mutant K-ras expression. Kaplan-Meier survival analysis showed that whereas all LSL-K-ras-Elane(+/+) mice died, none of the mice lacking neutrophil elastase died. Neutrophil elastase directly induced tumor cell proliferation in both human and mouse lung adenocarcinomas by gaining access to an endosomal compartment within tumor cells, where it degraded insulin receptor substrate-1 (IRS-1). Immunoprecipitation studies showed that, as neutrophil elastase degraded IRS-1, there was increased interaction between phosphatidylinositol 3-kinase (PI3K) and the potent mitogen platelet-derived growth factor receptor (PDGFR), thereby skewing the PI3K axis toward tumor cell proliferation. The inverse relationship identified between neutrophil elastase and IRS-1 in LSL-K-ras mice was also identified in human lung adenocarcinomas, thus translating these findings to human disease. This study identifies IRS-1 as a key regulator of PI3K within malignant cells. Additionally, to our knowledge, this is the first description of a secreted proteinase gaining access to the inside of a cell and altering intracellular signaling.