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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined possible roles of keratinocyte growth factor (KGF) and hepatocyte growth factor (HGF) in lung morphogenesis. By polymerase chain reaction, transcripts for both KGF and its receptor were detected early (rat gestational days 16 and 14, respectively) and their abundance increased during lung morphogenesis. To evaluate possible role of KGF in lung morphogenesis, day 14 lung explants were cultured in Dulbecco's modified Eagle medium + 10% fetal calf serum for 1 to 4 days in the presence (5-50 ng/ml) or absence of KGF (control). KGF (at 25 and 50 ng/ml) induced a marked reduction in the number of terminal branches and destination of the distal epithelium into cyst-like structures. These effects of exogenous KGF were progressively diminished by increasing concentrations of anti-KGF (2-16 micrograms/ml). Electron microscopic examination revealed that the epithelial cells of the cystic structures contained lamellar bodies, and were therefore type II cells and/or their progenitors. Northern blot analysis showed higher expression of surfactant protein C (SP-C) mRNA (a marker for alveolar epithelial type II cells) in KGF-treated fetal lungs. In situ hybridization of the KGF-treated lungs revealed that the SP-C mRNA-expressing cells were arranged distally in the form of linear arrays, a pattern distinctly different from that in control lungs. Acidic fibroblast growth factor, which also binds KGF receptors, in the presence of heparin mimicked the effect of KGF on branching. Transforming growth factor-beta(1) (TGF-beta 1) inhibited branching of fetal lungs in culture, and this effect dominated over that induced by KGF. Blocking of endogenous HGF with antibodies or addition of HGF to cultures of fetal lung explants had no significant effect on branching or growth. In conclusion, KGF markedly influences branching, and epithelial growth, differentiation, and patterning during lung morphogenesis.
Am J Respir Cell Mol Biol 1996 Sep
PMID:Keratinocyte growth factor and embryonic rat lung morphogenesis. 881 Jun 36

Hepatocyte growth factor (HGF) has different effects on different cell types. Recently, it has been reported that HGF has an anti-proliferative effect against tumor cells including hepatocellular carcinoma (HCC) cells. To clarify whether HGF inhibits the metastasis of HCC cells in vivo, we examined the metastatic potential of HCC cells into liver where HGF was highly expressed in transgenic animals. Three HCC cell lines including HuH7, Hep3B and FaO cells were transplanted into liver through the portal vein in chimeric mice or HGF transgenic mice and athymic nude mice (HGF/nude). The incidence of liver metastasis and number of metastatic tumors were significantly lower in mice expressing HGF (HGF/nude), compared with their siblings expressing no HGF (+/nude) (p < 0.05 and p = 0.002, respectively). These data suggest that HGF really inhibits metastasis of HCC cells in vivo.
Res Commun Mol Pathol Pharmacol 1996 Jan
PMID:Inhibitory effect of hepatocyte growth factor on metastasis of hepatocellular carcinoma in transgenic mice. 882 29

Hepatocyte growth factor/scatter factor (HGF/SF) is a pleiotropic effector of cells expressing the Met tyrosine kinase receptor. While HGF/SF-Met signaling clearly plays a role in a variety of normal cellular process, this signaling pathway has also been implicated in the generation and metastatic spread of tumors. This review discusses in detail several model systems that have been developed to investigate the role of HGF/SF-Met signaling in malignancy and describes additional data regarding the expression of these molecules in human tumors. Collectively the findings support a role for this receptor-ligand pair in human malignancy.
J Mol Med (Berl) 1996 Sep
PMID:Hepatocyte growth factor/scatter factor-Met signaling in tumorigenicity and invasion/metastasis. 889 55

Alveolar epithelial injury occurs universally in common respiratory illnesses associated with diffuse lung damage. After alveolar injury, type II cells proliferate and reestablish epithelial integrity, thereby restoring normal lung structure and function. However, the regulation of type II cell proliferation and alveolar epithelial repair is poorly understood. Hepatocyte growth factor/scatter factor (HGF/SF) is a heparin-binding growth factor that has been shown to be mitogenic for cultured alveolar type II cells. In this study, we determined the effect of intratracheal instillation of rhHGF/SF on type II cell proliferation in vivo. To quantify the alveolar type II cell proliferative response, we developed a double-label immunohistochemical technique to detect replicating alveolar type II cells in formalin-fixed lung sections that utilized the identification of proliferating cells by bromodeoxyuridine (BrdUrd) incorporation into DNA and alveolar type II cells by 3F9 immunoreactivity. BrdUrd detection was optimized by enzymatic antigen recovery and silver intensification of the horseradish peroxidase reaction product. Intratracheal instillation of rhHGF/SF induced a time- and dose-dependent increase in type II cell proliferation. The type II cell labeling index increased to 12.3 +/- 6.0% 48 h after 1.0 mg/kg rhHGF/SF administration, compared with 2.6 +/- 0.9% after PBS instillation. To compare the normal type II cell reparative response with the level of proliferation after exogenous rhHGF/SF administration, we measured the specific alveolar type II cell labeling index in rat lung sections obtained from animals exposed to hyperoxia for 50 h and then allowed to recover in room air. After 1 day of recovery, the alveolar type II cell labeling index was 0.45 +/- 0.2%. The specific labeling index increased to 5.4 +/- 1.3% at 2 days and then declined to 0.31 +/- 0.16% 5 days after hyperoxia exposure. In animals not exposed to hyperoxia, the alveolar type II cell labeling index was 0.6 +/- 0.14%. These studies demonstrated that intratracheal instillation of rhHGF/SF promoted alveolar type II cell proliferation in vivo. The maximal level of type II cell proliferation after rhHGF/SF administration was more than twice that reached during recovery from hyperoxia exposure. Thus, intratracheal instillation of HGF/SF may provide a potential strategy to promote type II cell proliferation and augment alveolar epithelial repair after lung injury.
Am J Respir Cell Mol Biol 1996 Nov
PMID:Intratracheal administration of hepatocyte growth factor/scatter factor stimulates rat alveolar type II cell proliferation in vivo. 891 64

Gomisin A (Go), a lignan component of shizandra fruits, protects the liver from injury by acetaminophen (AAP). One of its possible mechanisms is supposed to be related to the suppression of lipid peroxidation. Since hepatocyte growth factor (HGF) was reported to prevent hepatotoxin-induced liver damage, we tested HGF as the intermediary of Go effects. Simultaneous analyses of HGF mRNA expression and liver histology in rats were performed at 6 and 24 hr after treatment with AAP, Go or both. HGF mRNA rapidly expressed at 6 hr after Go treatment, while no HGF mRNA was observed at 6 hr after AAP treatment. Induction of HGF mRNA at 24 hr was observed after treatment with AAP or AAP plus Go. Histological findings indicate that massive necrosis and vacuolization in the liver of rats treated with both AAP and Go were reduced in comparison with rats treated with AAP only. These data suggest that Go rapidly induces HGF mRNA through different mechanisms from AAP-induced liver injury.
Res Commun Mol Pathol Pharmacol 1996 Nov
PMID:Rapid induction of hepatocyte growth factor mRNA after administration of gomisin A, a lignan component of shizandra fruits. 898 11

The Met tyrosine kinase receptor is a widely expressed molecule which mediates pleiotropic cellular responses following activation by its ligand, hepatocyte growth factor/scatter factor (HGF/SF). In this communication we demonstrate that significant Met degradation is induced by HGF/SF and that this degradation can be blocked by lactacystin, an inhibitor of proteasome activity. We also show that Met is rapidly polyubiquitinated in response to ligand and that polyubiquitinated Met molecules, which are normally unstable, are stabilized by lactacystin. Both HGF/SF-induced degradation and polyubiquitination of Met were shown to be dependent on the receptor possessing intact tyrosine kinase activity. Finally, we found that a normally highly labile 55-kDa fragment of the Met receptor is stabilized by lactacystin and demonstrate that it represents a cell-associated remnant that is generated following the ligand-independent proteolytic cleavage of the Met receptor in its extracellular domain. This truncated Met molecule encompasses the kinase domain of the receptor and is itself tyrosine phosphorylated. We conclude that the ubiquitin-proteasome pathway plays a significant role in the degradation of the Met tyrosine kinase receptor as directed by ligand-dependent and -independent signals. We propose that this proteolytic pathway may be important for averting cellular transformation by desensitizing Met signaling following ligand stimulation and by eliminating potentially oncogenic fragments generated via extracellular cleavage of the Met receptor.
Mol Cell Biol 1997 Feb
PMID:Degradation of the Met tyrosine kinase receptor by the ubiquitin-proteasome pathway. 900 Dec 34

Pulmonary fibrosis is a chronic inflammatory disorder characterized by diffuse fibrous remodeling of alveolar spaces. Although much interest is focused on mechanisms of the inflammatory process in pulmonary fibrosis, little is known about the repair and regenerative process. Hepatocyte growth factor (HGF), originally discovered as a mitogen for hepatocyte regeneration, is now recognized as a multifunctional mesenchymal factor for epithelial regeneration, including the regeneration of alveolar type II epithelial cells. Involvement of HGF and its receptor (c-met) is evident in animal models of acute lung injury produced by hydrochloride inhalation. We studied the role of HGF in patients with idiopathic pulmonary fibrosis (IPF) (25 cases), lung fibrosis associated with rheumatoid arthritis (22 cases), and sarcoidosis (39 cases). Immunohistochemical evaluation demonstrated that hyperplastic alveolar type II epithelial cells, as well as alveolar macrophages, were strongly stained with anti-HGF antibody in tissues of patients with IPF. The concentration of HGF in bronchoalveolar lavage fluid (BALF) was significantly higher than in normal controls (0.23 +/- 0.09 pg/microg) in patients with IPF (0.77 +/- 0.88 pg of HGF/microg of albumin, P < 0.001), lung fibrosis associated with rheumatoid arthritis (0.50 +/- 0.64 pg/microg, P < 0.01), and sarcoidosis (0.41 +/- 0.61 pg/microg, P < 0.05). In situ hybridization revealed mRNA for HGF in alveolar macrophages (especially small monocytelike macrophages). These results indicate that the increase in HGF concentration in patients' peripheral air spaces is due to augmented HGF production by alveolar epithelial cells and alveolar macrophages. HGF, through a paracrine mechanism, may play an important role in the repair and healing of the inflammatory lung damage in pulmonary fibrosis.
Am J Respir Cell Mol Biol 1997 Apr
PMID:Hepatocyte growth factor in bronchoalveolar lavage fluids and cells in patients with inflammatory chest diseases of the lower respiratory tract: detection by RIA and in situ hybridization. 911 49

Liver regeneration is significantly impaired in rats with both alpha-adrenergic hepatic denervation and hereditary vasopressin deficiency. This may implicate a direct role for these agonists in the process of compensatory hyperplasia. The mitogenic capacities of norepinephrine, vasopressin and hepatocyte growth factor (HGF), either alone or in combination were investigated by [3H]thymidine incorporation into hepatocyte cultures prepared from normal and regenerating rat livers. The results show that normal hepatocytes incorporate less [3H]thymidine in response to HGF than do regenerating hepatocytes. In addition, physiological concentrations of vasopressin cause a synergistic stimulation of [3H]thymidine uptake in rat liver cells in the presence of HGF.
J Mol Endocrinol 1997 Apr
PMID:Vasopressin synergistically stimulates DNA synthesis in normal and regenerating rat liver cell cultures in the presence of hepatocyte growth factor. 913 2

We have previously shown that rat liver epithelial cells (RLEC) transfected with and constitutively expressing transforming growth factor-alpha (TGF-alpha) have an enhanced mitogenic response to hepatocyte growth factor (HGF). In the study reported here, we examined tumor clones derived from the TGF-alpha transfectants with respect to mitogenic response to HGF. Tumor cell lines that expressed TGF-alpha responded to HGF with a greater increase in DNA synthesis than did the nontransfected parental RLEC (pRLEC). The tumor clones had also acquired a lower threshold for HGF response, which enabled them to undergo significant DNA synthesis at a low concentration of HGF that did not evoke a response in the pRLEC or TGF-alpha transfectants. We investigated the mechanisms by which TGF-alpha expression may influence the HGF/c-met pathway. We showed that most TGF-alpha transfectants and tumor cells displayed increases in c-met mRNA and protein, indicating that the enhanced HGF response may be due in part to an increase in the amount of receptor present. However, in all transfectants and tumor clones that constitutively expressed TGF-alpha, c-met was tyrosine phosphorylated in the absence of ligand (HGF) or other exogenous growth factors. These data suggest that induction of c-met mRNA and transactivation of c-met may be a sequela of the constitutive expression of TGF-alpha and that constitutive activation of the epidermal growth factor receptor pathway leads to phosphorylation and activation of c-met. These studies provide evidence for a novel mechanism of communication between epidermal growth factor receptor and c-met pathways that may partially explain the synergistic effects reported between TGF-alpha and HGF.
Mol Carcinog 1997 Apr
PMID:Modifications of the hepatocyte growth factor/c-met pathway by constitutive expression of transforming growth factor-alpha in rat liver epithelial cells. 914 19

Anchorage-independent growth is a property of malignant cells. Extracellular matrix proteins are present in tumor spheroids but their function is not clearly defined. In this paper we show that a murine mammary carcinoma cell line, SP1, which expresses the fibronectin receptor alpha 5 beta 1 requires fibronectin for anchorage-independent growth in soft agar. Growth factors (hepatocyte growth factor and transforming growth factor-beta) also promote SP1 colony growth. In contrast, collagen types I and IV have an inhibitory effect on SP1 colony growth. A clone isolated from SP1 cells which expresses the collagen/laminin receptor alpha 2 beta 1 as well as the fibronectin receptor alpha 5 beta 1, demonstrates increased colony formation in the presence of fibronectin and collagen. These data suggest a role for both the alpha 5 beta 1 and alpha 2 beta 1 integrin receptors in the regulation of anchorage-independent growth of mammary carcinoma cells.
Cell Mol Biol (Noisy-le-grand) 1997 May
PMID:The role of integrins and extracellular matrix in anchorage-independent growth of a mammary carcinoma cell line. 919 1


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