Dataset Information

Activation of PPAR? in Myeloid Cells Promotes Progression of Epithelial Lung Tumors through TGF?1.

ABSTRACT: Lung cancer is a heterogeneous disease in which patient-specific treatments are desirable and the development of targeted therapies has been effective. Although mutations in KRAS are frequent in lung adenocarcinoma, there are currently no targeted agents against KRAS. Using a mouse lung adenocarcinoma cell line with a Kras mutation (CMT167), we previously showed that PPAR? activation in lung cancer cells inhibits cell growth in vitro yet promotes tumor progression when activated in myeloid cells of the tumor microenvironment. Here, we report that PPAR? activation in myeloid cells promotes the production of TGF?1, which, in turn, acts on CMT167 cancer cells to increase migration and induce an epithelial-mesenchymal transition (EMT). Targeting TGF?1 signaling in CMT167 cells prevented their growth and metastasis in vivo. Similarly, another mouse lung adenocarcinoma cell line with a Kras mutation, LLC, induced TGF?1 in myeloid cells through PPAR? activation. However, LLC cells are more mesenchymal and did not undergo EMT in response to TGF?1, nor did LLC require TGF?1 signaling for metastasis in vivo. Converting CMT167 cells to a mesenchymal phenotype through overexpression of ZEB1 made them unresponsive to TGF?1 receptor inhibition. The ability of TGF?1 to induce EMT in lung tumors may represent a critical process in cancer progression. We propose that TGF? receptor inhibition could provide an additional treatment option for KRAS-mutant epithelial lung tumors.Implications: This study suggests that TGF? receptor inhibitors may be an effective therapy in a subset of KRAS-mutant patients with non-small cell lung cancer, which show an epithelial phenotype.

SUBMITTER: Sippel TR

PROVIDER: S-EPMC7439607 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Activation of PPARγ in Myeloid Cells Promotes Progression of Epithelial Lung Tumors through TGFβ1.

Sippel Trisha R TR Johnson Amber M AM Li Howard Y HY Hanson Dwight D Nguyen Teresa T TT Bullock Bonnie L BL Poczobutt Joanna M JM Kwak Jeff W JW Kleczko Emily K EK Weiser-Evans Mary C MC Nemenoff Raphael A RA

Molecular cancer research : MCR 20190514 8

Lung cancer is a heterogeneous disease in which patient-specific treatments are desirable and the development of targeted therapies has been effective. Although mutations in KRAS are frequent in lung adenocarcinoma, there are currently no targeted agents against KRAS. Using a mouse lung adenocarcinoma cell line with a Kras mutation (CMT167), we previously showed that PPARγ activation in lung cancer cells inhibits cell growth in vitro yet promotes tumor progression when activ ...[more]

PMID: 31088909

Similar Datasets

Project description:Emerging evidence shows that signal transducer and activator of transcription 6 (STAT6) plays critical roles in tumor development. We previously found high-level expression of STAT6 in human lung adenocarcinoma and squamous cell carcinoma, specifically in infiltrated immune cells located in the lung interstitium. Nevertheless, the role of STAT6 signaling in lung carcinogenesis and lung cancer proliferation and its underlying mechanisms remain unclear. This study aimed to investigate the role of STAT6 and the interaction between STAT6 and the tumor microenvironment in pulmonary tumorigenesis. We established a murine model of primary lung carcinogenesis in STAT6-deficient (STAT6-/-) and STAT6 wild-type (WT) BALB/c mice using the carcinogen urethane. Two-month-old male mice were intraperitoneally injected with urethane (1 g/kg) dissolved in phosphate buffered saline (PBS). Primary tumors were monitored in vivo by positron emission tomography scanning. At 4, 6, and 9 months after urethane injection, lung tumors were harvested from the STAT6-/- and WT mice for analysis. Small interfering RNA was used to downregulate the expression of STAT6 in tumor cells. Fluorescence activated cell sorting analysis was used to analyze fluorescence-conjugated cell markers. Transwell assays were used in coculturing experiments. STAT6 protein expression was detected by Western blotting, immunohistochemistry, and immunofluorescence. STAT6 mRNA expression was detected by quantitative real time-polymerase chain reaction. Cell Counting Kit-8 and colony formation assays were performed to evaluate cell proliferation. We detected high expression of STAT6 in CD11b+ cells of lung carcinoma. Our results indicate that STAT6 deficiency inhibits carcinogen-induced tumor growth and improves prognosis. STAT6 deficiency also decreased the mobilization and differentiation of CD11b+ cells. STAT6 deficiency in CD11b+ cells but not tumor cells decreased interleukin (IL)-4 secretion and the differentiation of CD11b+ cells into M2 macrophage cells. In conclusion, our findings indicate that IL-4/STAT6 signaling in CD11b+ cells promotes lung cancer progression by triggering an IL-4 positive feedback loop and increasing M2 myeloid cells. STAT6 may be a new therapeutic target for the prevention and treatment of lung cancer.

Project description:Respiratory distress in severe malaria is associated with high mortality, but its pathogenesis remains unclear. The malaria pigment hemozoin (HZ) is abundant in target organs of severe malaria, including the lungs, and is known to be a potent innate immune activator of phagocytes. We hypothesized that HZ might also stimulate lung epithelial activation and thereby potentiate lung inflammation. We show here that airway epithelium stimulated with HZ undergoes global transcriptional reprogramming and changes in cell surface protein expression that comprise an epithelial activation phenotype. Proinflammatory signaling is induced, and key cytoadherence molecules are upregulated, including several associated with severe malaria, such as CD36 and ICAM1. Epithelial and extracellular matrix remodeling pathways are transformed, including induction of key metalloproteases and modulation of epithelial junctions. The overall program induced by HZ serves to promote inflammation and neutrophil transmigration, and is recapitulated in a murine model of HZ-induced acute pneumonitis. Together, our data demonstrate a direct role for hemozoin in stimulating epithelial activation that could potentiate lung inflammation in malaria.IMPORTANCE Respiratory distress (RD) is a complication of severe malaria associated with a particularly high risk for death in African children infected with the parasite Plasmodium falciparum The pathophysiology underlying RD remains poorly understood, and the condition is managed supportively. The parasite-derived factor HZ accumulates in target organs of severe malaria, including the lungs, and is a potent stimulator of immune cells. Our findings demonstrate that HZ causes global activation of lung epithelial cells, a response that directly promotes lung inflammation. HZ stimulates expression of key proinflammatory and cell surface molecules, alters signaling pathways involved in epithelial-matrix remodeling, and promotes neutrophil transmigration and airway inflammation. The lung epithelial activation induced by HZ mimics patterns seen in malarial lung injury and provides new insights into the molecular pathogenesis of RD.

Project description:BackgroundRadiotherapy is the main treatment modality for thoracic tumours, but it may induce pulmonary fibrosis. Currently, the pathogenesis of radiation-induced pulmonary fibrosis (RIPF) is unclear, and effective treatments are lacking. Transforming growth factor beta 1 (TGFβ1) plays a central role in RIPF. We found that activated TGFβ1 had better performance for radiation pneumonitis (RP) risk prediction by detecting activated and total TGFβ1 levels in patient serum. αv integrin plays key roles in TGFβ1 activation, but the role of αv integrin-mediated TGFβ1 activation in RIPF is unclear. Here, we investigated the role of αv integrin-mediated TGFβ1 activation in RIPF and the application of the integrin antagonist cilengitide to prevent RIPF.MethodsItgavloxP/loxP ;Pdgfrb-Cre mice were generated by conditionally knocking out Itgav in myofibroblasts, and wild-type mice were treated with cilengitide or placebo. All mice received 16 Gy of radiation or underwent a sham radiation procedure. Lung fibrosis was measured by a modified Ashcroft score and microcomputed tomography (CT). An enzyme-linked immunosorbent assay (ELISA) was used to measure the serum TGFβ1 concentration, and total Smad2/3 and p-Smad2/3 levels were determined via Western blotting.ResultsConditional Itgav knockout significantly attenuated RIPF (p < .01). Hounsfield units (HUs) in the lungs were reduced in the knockout mice compared with the control mice (p < .001). Conditional Itgav knockout decreased active TGFβ1 secretion and inhibited fibroblast p-Smad2/3 expression. Exogenous active TGFβ1, but not latent TGFβ1, reversed these reductions. Furthermore, cilengitide treatment elicited similar results and prevented RIPF.ConclusionsThe present study revealed that conditional Itgav knockout and cilengitide treatment both significantly attenuated RIPF in mice by inhibiting αv integrin-mediated TGFβ1 activation.HighlightsActivated TGFβ1 has a superior capacity in predicting radiation pneumonitis (RP) risk and plays a vital role in the development of radiation-induced pulmonary fibrosis (RIPF). Conditional knock out Itgav in myofibroblasts prevented mice from developing RIPF. Cilengitide alleviated the development of RIPF by inhibiting αv integrin-mediated TGFβ1 activation and may be used in targeted approaches for preventing RIPF.

Dataset Information

Activation of PPAR? in Myeloid Cells Promotes Progression of Epithelial Lung Tumors through TGF?1.

Publications

Activation of PPARγ in Myeloid Cells Promotes Progression of Epithelial Lung Tumors through TGFβ1.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets