title: Bronchioalveolar morphogenesis of human bronchial epithelial cells depending upon hepatocyte growth factor.
abstract: Lung alveolar regeneration occurs in adult human lungs as a result of proliferation, differentiation and alveolar morphogenesis of stem cells. It is increasingly being believed that bronchial epithelial cells (BECs) have a potential as stem cells, because they are potent to differentiate into multiple central and peripheral lung cell types in three-dimensional (3D) cultures, and they develop multiple foci with well-differentiated histogenesis after transformed into neoplastic cells. In this study, we investigated morphogenic abilities of HBE135 human BECs immortalized by E6/E7 oncogene in 3D cultures. When HBE135 cells were cultured alone or co-cultured with endothelial cells, the cells formed spherical colonies without branching. However, in co-culture with lung fibroblast MRC-9 cells, HBE135 cells formed colonies with bronchioalveolar-like complex branching, suggesting that MRC-9-derived soluble factor(s) are responsible for the branching formation. MRC-9 cells, not endothelial cells, were found to highly express hepatocyte growth factor (HGF), a soluble molecule involved in liver and kidney regeneration. An anti-HGF neutralizing antibody severely suppressed the complex branching formation, but addition of HGF could not sufficiently compensate the morphogenic effects of MRC-9 cells, suggesting that MCR-9-derived HGF was necessary but insufficient for the bronchioalveolar structure formation. Immunohistochemistry revealed that Met, a cognate receptor for HGF, was highly expressed and phosphorylated in neoplastic BECs from lung adenocarcinomas with well-differentiated, not poorly differentiated, histogenesis. These results are consistent with the notion that BECs have an aspect of stem cells. This aspect appears to become manifest through HGF-Met signalling pathway activation.
authors.affiliation: Department of Pathology, Faculty of Medicine, Kinki University, Osaka-Sayama, Osaka, Japan.|Department of Pharmacology, Faculty of Medicine, Kinki University, Osaka-Sayama, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kato
authors.affiliation: Research & Development, Neurogen Inc., Ibaraki, Osaka, Japan.
authors.forename: Kiyomasa
authors.initials: K
authors.lastname: Oka
authors.affiliation: Research & Development, Neurogen Inc., Ibaraki, Osaka, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Department of Pathology, Faculty of Medicine, Kinki University, Osaka-Sayama, Osaka, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ito
mesh_terms: D015153:Blotting, Western; D001980:Bronchi / Q000166:cytology; D055745:Bronchioles / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D018929:Cell Culture Techniques / Q000379:methods; D002460:Cell Line; D002461:Cell Line, Transformed; D018920:Coculture Techniques; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects / Q000502:physiology; D004847:Epithelial Cells / Q000187:drug effects* / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic; D017228:Hepatocyte Growth Factor / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D018613:Microscopy, Confocal; D009024:Morphogenesis / Q000187:drug effects* / Q000502:physiology; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018874:Spheroids, Cellular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
chemical_list: D016207:Cytokines; D017228:Hepatocyte Growth Factor; D019859:Proto-Oncogene Proteins c-met
keywords: alveolar regeneration; bronchial cell; hepatocyte growth factor; lung adenocarcinoma histogenesis; three-dimensional culture