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Objectives: The ADAMs (a disintegrin and metalloproteinase) enzymes compose a family of membrane-bound proteins characterized by their multi-domain structure and ADAM-12 expression is elevated in human non-small cell lung cancers. The aim of this study was to investigate the roles played by ADAM-12 in critical steps of bronchial cell transformation during carcinogenesis. Materials and methods: To assess the role of ADAM-12 in tumorigenicity, BEAS-2B cells were transfected with a plasmid encoding human full-length ADAM-12 cDNA, and then the effects of ADAM-12 overexpression on cell behaviour were explored. Treatment of clones with heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) neutralizing antibodies as well as an EGFR inhibitor allowed the dissection of mechanisms regulating cell proliferation and apoptosis. Results: Overexpression of ADAM-12 in BEAS-2B cells promoted cell proliferation. ADAM-12 overexpressing clones produced higher quantities of HB-EGF in their culture medium which may rely on membrane-bound HB-EGF shedding by ADAM-12. Targeting HB-EGF activity with a neutralizing antibody abrogated enhanced cell proliferation in the ADAM-12 overexpressing clones. In sharp contrast, targeting of amphiregulin, EGF or transforming growth factor-α failed to influence cell proliferation; moreover, ADAM-12 transfectants were resistant to etoposide-induced apoptosis and the use of a neutralizing antibody against HB-EGF activity restored rates of apoptosis to be similar to controls. Conclusions: ADAM-12 contributes to enhancing HB-EGF shedding from plasma membranes leading to increased cell proliferation and reduced apoptosis in this bronchial epithelial cell line. [ABSTRACT FROM AUTHOR]

Lungs are exposed to the outside environment and therefore to toxic and infectious agents or allergens. This may lead to permanent activation of innate immune response elements. A Disintegrin And Metalloproteinases (ADAMs) and ADAMs with Thrombospondin motifs (ADAMTS) are proteinases closely related to Matrix Metalloproteinases (MMPs). These multifaceted molecules bear metalloproteinase and disintegrin domains endowing them with features of both proteinases and adhesion molecules. Proteinases of the ADAM family are associated to various physiological and pathological processes and display a wide spectrum of biological effects encompassing cell fusion, cell adhesion, "shedding process", cleavage of various substrates from the extracellular matrix, growth factors or cytokines... This review will focus on the putative roles of ADAM/ADAMTS proteinases in airway diseases such as asthma and COPD. [ABSTRACT FROM AUTHOR]