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

ABSTRACT: 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.

SUBMITTER: Houghton AM

PROVIDER: S-EPMC2821801 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature

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

Houghton A McGarry AM Rzymkiewicz Danuta M DM Ji Hongbin H Gregory Alyssa D AD Egea Eduardo E EE Metz Heather E HE Stolz Donna B DB Land Stephanie R SR Marconcini Luiz A LA Kliment Corrine R CR Jenkins Kimberly M KM Beaulieu Keith A KA Mouded Majd M Frank Stuart J SJ Wong Kwok K KK Shapiro Steven D SD

Nature medicine 20100117 2

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 express ...[more]

PMID: 20081861

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Project description:BACKGROUND:In acutely injured lungs, massively recruited polymorphonuclear neutrophils (PMNs) secrete abnormally neutrophil elastase (NE). Active NE creates a localized proteolytic environment where various host molecules are degraded leading to impairment of tissue homeostasis. Among the hallmarks of neutrophil-rich pathologies is a disrupted epithelium characterized by the loss of cell-cell adhesion and integrity. Epithelial-cadherin (E-cad) represents one of the most important intercellular junction proteins. E-cad exhibits various functions including its role in maintenance of tissue integrity. While much interest has focused on the expression and role of E-cad in different physio- and physiopathological states, proteolytic degradation of this structural molecule and ensuing potential consequences on host lung tissue injury are not completely understood. METHODS:NE capacity to cleave E-cad was determined in cell-free and lung epithelial cell culture systems. The impact of such cleavage on epithelial monolayer integrity was then investigated. Using mice deficient in NE in a clinically relevant experimental model of acute pneumonia, we examined whether degraded E-cad is associated with lung inflammation and injury and whether NE contributes to E-cad cleavage. Finally, we checked for the presence of both degraded E-cad and NE in bronchoalveolar lavage samples obtained from patients with exacerbated COPD, a clinical manifestation characterised by a neutrophilic inflammatory response. RESULTS:We show that NE is capable of degrading E-cad in vitro and in cultured cells. NE-mediated degradation of E-cad was accompanied with loss of epithelial monolayer integrity. Our in vivo findings provide evidence that NE contributes to E-cad cleavage that is concomitant with lung inflammation and injury. Importantly, we observed that the presence of degraded E-cad coincided with the detection of NE in diseased human lungs. CONCLUSIONS:Active NE has the capacity to cleave E-cad and interfere with its cell-cell adhesion function. These data suggest a mechanism by which unchecked NE participates potentially to the pathogenesis of neutrophil-rich lung inflammatory and tissue-destructive diseases.

Dataset Information

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

Publications

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

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