Up-regulation of hepatocyte growth factor gene expression by interleukin-1 in human skin fibroblasts

Hepatocyte growth factor/scatter factor inhibits UVB-induced apoptosis of human keratinocytes but not of keratinocyte-derived cell lines via the phosphatidylinositol 3-kinase/AKT pathway

Acute irreparable UV-induced DNA damage leads to apoptosis of epidermal keratinocytes (KC) and the formation of sunburn cells, whereas less severely damaged cells survive but harbor the potential of tumor formation. Here we report that hepatocyte growth factor/scatter factor (HGF/SF) prevents UVB-induced apoptosis in primary KC cultured in vitro. When we analyzed the signaling pathways initiated by the HGF/SF receptor c-met, we found that the phosphatidylinositol (PI) 3-kinase and its downstream-element AKT and the mitogen-activated protein (MAP) kinase were activated. Inhibition of PI 3-kinase led to a complete abrogation of the anti-apoptotic effect of HGF/SF, whereas blockade of the MAP kinase pathway had no effect. In contrast to the observation with primary KC, HGF/SF could not enhance survival after UVB irradiation of HaCaT and A431 cell lines, despite the fact that in these cells the PI 3-kinase and MAP kinase pathways were also activated by HGF/SF. Cell cycle analysis of KC revealed a G(2)/M arrest after UVB irradiation and a complete loss of proliferating cells. Because HGF/SF in the skin is produced by dermal fibroblasts, our findings suggest that the HGF/SF-mediated rescue of KC from apoptosis represents an important paracrine loop by which UVB-damaged KC can be kept alive to maintain the epidermal barrier function but cannot further proliferate, thereby preventing the induction of epithelial skin tumors.

Hepatocyte growth factor production may be related to the inflammatory response in patients with acute myocardial infarction

Hepatocyte growth factor (HGF) is a well-known powerful proliferative factor of vascular endothelial cells and it has been reported that plasma HGF concentrations are increased in acute myocardial infarction (AMI), although the mechanisms are not yet well delineated. Serum HGF levels and C-reactive protein (CRP) were measured in 22 patients with unstable angina pectoris (UAP) (15 males, 7 females; class IIb or IIIb of the Braunwald classification), 60 patients with AMI (37 males, 23 females; average time from the onset of symptoms to admission 4.6+/-0.7h, range, 0.5-12h), and 20 normal subjects. Immediate angioplasties were performed in 51 patients with AMI, and the time course of the HGF levels were measured in 31 patients among them. Heparin dramatically increased the HGF level and it declined to the normal range 18h after heparin injection. Blood samples were taken before heparin treatment, or at least 24h after. Serum HGF levels on admission was significantly increased in UAP (mean+/-SE: 0.30+/-0.03ng/ml, p<0.01), and AMI (0.27+/-0.02ng/ml, p<0.01) compared with the normal subjects (0.19+/-0.01 ng/ml). Even in the early stage (within 3 h of onset of symptoms to admission, average time was 1.8+/-0.1 h), serum HGF levels were already elevated (0.25+/-0.02 ng/ml, p<0.05). There was no significant difference between the HGF levels in UAP and AMI. Fifty-one of the 60 patients with AMI underwent immediate percutaneous transluminal coronary angioplasty and blood samples were obtained from 31 of them on days 7, 14, and 21 after MI. Serum HGF levels peaked on day 7 (0.34+/-0.04ng/ml, p<0.01) and there was a weak relationship between peak creatine kinase and serum HGF levels at that time. A statistically significant correlation was found between peak CRP and serum HGF levels on day 7 (r=0.62: p<0.001). Serum HGF levels decreased to nearly normal by day 21 (0.22+/-0.01 ng/ml). The study shows that serum HGF levels during the early stage of AMI increased significantly and peaked by day 7 after the onset, at which time there was a strong correlation with peak CRP levels. These data suggest that HGF production may be related to the inflammatory response in AMI.

Hormone/growth factor interactions mediating epithelial/stromal communication in mammary gland development and carcinogenesis

Epithelial/mesenchymal interactions begin during embryonic development of the mammary gland and continue throughout mammary gland development into adult life. Stromal and epithelial growth factors that may mediate interactions between these compartments of the mammary gland are reviewed. Since mammogenic hormones are the primary regulators of mammary gland development, special consideration is given to hormonal regulation of growth factors in order to explore the integration of hormones and growth factors in the regulation of mammary gland growth and neoplasia. Examination of hormonal regulation of the fibroblast growth factor (FGF)-7/FGFR2-IIIb receptor system in the mammary gland reveals that mammogenic hormones differentially regulate the synthesis of stromal growth factors and their epithelial receptors. These effects serve to optimize the action of estrogen and progesterone on mammary gland development and illustrate that the ratio of these two hormones is critical in regulating this growth factor axis. The role of stromal/epithelial mitogenic microenvironments in modulating the genotype and phenotype of preneoplastic and neoplastic lesions by chemical carcinogens is discussed. Finally, changes in growth factor expression during mammary tumor progression are described to illustrate the relative roles that stromally-derived and epithelial-derived growth factors may play during progression to hormone independent tumor growth.

Expression of hepatocyte growth factor, keratinocyte growth factor and their receptors in experimental chronic pancreatitis

BACKGROUND

Hepatocyte (HGF) and Keratinocyte growth factors (KGF) are key factors of tissue organization and regeneration. These peptide growth factors and their receptors c-met and keratinocyte growth factor receptor (KGFR) are overexpressed in pancreatic cancer.

AIM

Expression and localization of ligands and receptors were investigated during the development of experimental chronic pancreatitis.

METHODS

Chronic pancreatitis was induced in rats by intravenous injection of dibutyltin dichloride. One to 60 days after treatment, the expression of growth factors and receptors was analysed by competitive polymerase chain reaction, Western blot analysis and immunohistochemistry.

RESULTS

HGF mRNA expression increased (10-fold) until days 7-14 followed by a decrease to control level. Expression of c-met mRNA constantly increased (15-fold). KGF and KGFR mRNA expression were increased after 14-28 days (5-fold) and then returned to control levels. mRNA expression patterns correlated with changes in the protein expression, whereas protein levels of KGF remained unchanged. Ligands were localized in mesenchymal cells and their receptors on epithelial cells.

CONCLUSIONS

The significant increase of HGF and c-met expression suggests an essential role of this growth factor in the morphological changes during the development of chronic pancreatitis. Changes in the expression of KGF and KGFR are less pronounced.

Peroxisome proliferator-activated receptor gamma-mediated transcriptional up-regulation of the hepatocyte growth factor gene promoter via a novel composite cis-acting element

Hepatocyte growth factor (HGF) is a pleotropic polypeptide that can function as a morphogen, motogen, mitogen, angiogen, carcinogen, and tumor suppressor, depending on the target cell and tissue. Previous studies from our laboratory using transgenic mice have shown that HGF gene expression is tightly regulated at the transcriptional level and that the upstream regulatory elements are crucial for the control of HGF gene transcription. In the present study, we have identified and characterized one of these elements as a peroxisome proliferator-activated receptor gamma (PPARgamma)-responsive element. This regulatory element was localized at -246 to -233 base pairs upstream from the transcription start site of the HGF gene promoter having the sequence GGGCCAGGTGACCT. Gel mobility shift and supershift assays demonstrated that this cis-acting element strongly binds to the PPARgamma isoforms as well as to chicken ovalbumin upstream promoter-transcription factor, a member of the orphan nuclear receptor subfamily. Mutational analysis and gel mobility band shift assays indicated that the binding site is an inverted repeat of the AGGTCA motif with two spacers (inverted repeat 2 configuration) and that the two spacers are important for PPARgamma binding. This binding site overlaps with functional binding sites for activating protein-2, nuclear factor 1, and upstream stimulatory factor, and together, they constitute a multifunctional composite binding site through which these different transcription factors exert their regulatory effects on HGF promoter activity. Functional assays revealed that PPARgamma, with its ligand, 15-deoxy-prostaglandin J2, strongly stimulates HGF promoter activity. On the other hand, nuclear factor 1, activating protein-2, and chicken ovalbumin upstream promoter-transcription factor transcription factors repress the stimulatory action of PPARgamma by competing with PPARgamma for their overlapping binding sites. Furthermore, for the first time, our studies demonstrate that the PPARgamma ligand, 15-deoxy-prostaglandin J2, induces endogenous HGF mRNA and protein expression in fibroblasts in culture.

Hepatocyte growth factor: renotropic role and potential therapeutics for renal diseases

Hepatocyte growth factor (HGF), a ligand for the c-Met receptor tyrosine kinase, has mitogenic, motogenic, anti-apoptotic, and morphogenic (for example, induction of branching tubulogenesis) activities for renal tubular cells, while it has angiogenic and angioprotective actions for endothelial cells. Stromal cells such as mesangial cells, endothelial cells, and macrophages are sources of renal HGF; thus, HGF mediates epithelial-stromal and endothelial-mesangial interactions in the kidney. In response to acute renal injury, the expression of HGF increases in the injured kidney and in distant intact organs such as the lung and spleen. Locally and systemically increased HGF supports renal regeneration, possibly not only by enhancing cell growth but also by promoting morphogenesis of renal tissue. During progression of chronic renal failure/renal fibrosis, the expression of HGF decreases in a manner reciprocal to the increase in expression of transforming growth factor-beta (TGF-beta), a key player in tissue fibrosis. A decrease in endogenous HGF, as well as increase in TGF-beta, augments susceptibility to the onset of chronic renal failure/renal fibrosis. On the other hand, supplements of exogenous HGF have preventive and therapeutic effects in cases of acute and chronic renal failure/renal fibrosis in laboratory animals. HGF prevents epithelial cell death and enhances regeneration and remodeling of renal tissue with injury or fibrosis. A renotropic system underlies the vital potential of the kidney to regenerate, while an impaired renotropic system may confer susceptibility to the onset of renal diseases. Thus, HGF supplementation may be one therapeutic strategy to treat subjects with renal diseases, as it enhances the intrinsic ability of the kidney to regenerate.

Theories of endometriosis

Endometriosis is characterised by the presence of abnormally located tissue resembling the endometrium with glands and stroma. Several hypotheses have attempted to explain the development of such tissue. The oldest theory, that of metaplasia, suggests that under diverse influences coelomic tissue could be transformed into endometrium. The most often cited theory, that of implantation, proposes that the physiological phenomenon of endometrial reflux in the fallopian tubes during menstruation may, in certain conditions, overcome local defense mechanisms, implant, and proliferate. The peritoneal fluid in unaffected women possesses the capacity to prevent endometriotic tissue from becoming established. The reasons for the occurrence of endometriosis and its consequences (pain, sterility, adhesions) are probably numerous and involve the endometrium, the immune system (macrophages, natural killer cells), the peritoneum, and fallopian tubes. The failure to clear the peritoneal cavity of fragments of endometrium could cause a state of local inflammation with hyperactivation of macrophages secreting a variety of different compounds. Some of these compounds may bring about metaplasia of the peritoneum or the development of Mullerian residues.

Alveolar Macrophages that Phagocytose Apoptotic Neutrophils Produce Hepatocyte Growth Factor during Bacterial Pneumonia in Mice

Hepatocyte growth factor (HGF) is postulated to play an important role in the repair of pulmonary epithelium in acute lung injury. To evaluate the role of HGF in bacterial pneumonia, the kinetics of HGF production and the cellular sources of HGF have been examined in the lungs of mice that had been intratracheally challenged with Pseudomonas aeruginosa. Neutrophil accumulation in the airway occurred immediately, reached a peak at 36 h, and then progressively declined by 14 d after infection. We found a biphasic pattern of HGF messenger RNA expression and protein synthesis in the lung after bacterial infection. The first peak for HGF production was found at 6 h after infection, and the primary source of HGF was shown to be bronchial epithelial cells. Interestingly, the second peak for HGF production, which was found around 48 to 72 h after infection, was closely associated with the increase in the percentage of alveolar macrophages (AMs) that became positive for myeloperoxidase, indicating phagocytosis of apoptotic neutrophils. The cellular source of the second peak was found to be AMs. Further, murine AMs which phagocytosed apoptotic neutrophils induced higher levels of HGF production in vitro. These results strongly indicate a novel mechanism of HGF production by AMs, which are phagocytosing apoptotic neutrophils, and the pivotal role of AMs in the healing and repair of damaged pulmonary epithelium through the production of HGF.

Hepatocyte growth factor is secreted by osteoblasts and cooperatively permits the survival of haematopoietic progenitors

Human osteoblasts (HOBs) support the growth of human haematopoietic progenitor cells, and support the survival and limited expansion of long-term culture-initiating cells. Using human CD34+ cells and the murine myelomonocytic cell line NFS-60 as targets, we previously found that one component of HOB-derived haematopoietic activity is cell-associated granulocyte colony-stimulating factor (G-CSF). However, antibody failed to neutralize all the activity, suggesting that more than one factor supports haematopoietic cells. In the present investigations, we asked whether the HOB-derived, non-G-CSF secreted activity was as a result of other known growth factors. We found that, among the cytokines expressed by HOBs, only hepatocyte growth factor (HGF) and G-CSF stimulated NFS-60 cell proliferation. HOB cells and osteosarcoma cells secreted biologically active HGF, although the levels varied considerably. Moreover, addition of neutralizing HGF antibody to CD34+ cell/HOB co-cultures resulted in a significant reduction ( approximately 50%) in the ability of the HOBs to support haematopoietic progenitor cells. These results suggest that a major component of osteoblast-derived haematopoietic activity is HGF. Secretion of HGF, in concert with cell-associated cytokines such as G-CSF, may account for the stem cell-stimulating activities of osteogenic cells and, thereby, the unique stem cell-supporting role of the osteoblasts within the bone marrow microenvironment.

Stimulation of hepatocyte growth factor production in human fibroblasts by the protein phosphatase inhibitor okadaic acid

In this study, we examined whether the production of hepatocyte growth factor (HGF) in fibroblasts is regulated by protein phosphatase(s). Inhibitors of the enzymes okadaic acid and calyculin A were used for this purpose. Both inhibitors markedly stimulated HGF production in human skin fibroblasts in a dose-dependent manner. The effects of okadaic acid and calyculin A were maximal at 25-37.5 and 1.25 nM, respectively. Highly active HGF production in MRC-5 human embryonic lung fibroblasts was also promoted by both inhibitors. The effect of okadaic acid was accompanied by an up-regulation of HGF gene expression. The stimulating effect of okadaic acid on HGF production was synergistic with that of phorbol 12-myristate 13-acetate (PMA) and epidermal growth factor (EGF), whereas it was additive to the effect of cholera toxin. The protein kinase C (PKC) inhibitor GF 109203X inhibited the effect of PMA, but not of okadaic acid and EGF. The effect of okadaic acid as well as EGF was not inhibited, but rather enhanced in human skin fibroblasts pretreated for 24 hr with a high dose of PMA to deplete PKC, as compared with its effect in untreated cells. PD 98059, an inhibitor of mitogen-activated protein (MAP) kinase kinase, suppressed the effects of okadaic acid and EGF, but not those of cholera toxin and 8-bromo-adenosine 3',5'-cyclic monophosphate (cAMP). These results suggest that HGF production in human skin fibroblasts is down-regulated by protein phosphatase(s) and that HGF production stimulated by okadaic acid is, at least in part, dependent on the activation of the MAP kinase cascade.

Induction of hepatocyte growth factor (HGF) in rat microglial cells by prostaglandin E(2)

Hepatocyte growth factor (HGF) is a multifunctional protein that exerts trophic effects on neural cells. HGF is expressed in normal brains and increased after brain injury. Recent studies suggest that neurons and astrocytes are the main producers of HGF in the brain. Here we report that microglia also produce HGF both in vitro and in vivo. Treatment of cultured microglia with prostaglandin E(2) (PGE(2)), one of the major inflammatory mediators in the brain, induced significant production of HGF, and this induction was suppressed by pretreatment with the adenylate cyclase inhibitor SQ22536, suggesting that the induction of HGF by PGE(2) in microglia proceeds via a cAMP-mediated pathway. We further investigated whether microglia also produce HGF in vivo under the pathological condition of cerebral ischemia. We found that HGF expression was increased after permanent occlusion of the middle cerebral artery (MCA), and double immunohistochemical staining revealed that the most of HGF-positive cells were microglia. PGE(2) level was increased 8 hr after start of MCA occlusion, and this enhancement is in parallel with the increase in HGF expression, suggesting that PGE(2) not only may induce HGF production in microglia in vitro but may also be an inducer in vivo.

Secretory leukoprotease inhibitor augments hepatocyte growth factor production in human lung fibroblasts

Secretory leukoprotease inhibitor (SLPI), an 11.7-kD nonglycosylated serine protease inhibitor, is produced and released into the fluids of mucosal surfaces including human lung. It comprises two domains with homologous amino acid sequences: the N-terminal domain possessing antibacterial activity, and the C-terminal domain with antiprotease activity. Here we report the positive regulation of hepatocyte growth factor (HGF) production in human lung fibroblasts exerted by SLPI or its C-terminal domain under physiologic concentrations (1 to 10 microM). This HGF production by SLPI was unaffected by the addition of interleukin (IL)-1 receptor antagonist. In contrast, human skin fibroblasts exerted no SLPI-stimulated increase in HGF production, despite the fact that IL-1beta increased HGF production with an intensity similar to that of human lung fibroblasts. Both the time-course and dose-response studies in human lung fibroblasts revealed that the induction of HGF messenger RNA (mRNA) and protein occurred in parallel, indicating that the mechanism existed at the steady-state mRNA level. A synthetic elastase inhibitor failed to induce HGF, but alpha(1)-antitrypsin also stimulated HGF production in lung fibroblasts. Inactivation of the antiprotease activity of SLPI or its C-terminal domain by an oxidizing agent (N-chlorosuccinimide) abolished their stimulatory effect on HGF production. These findings demonstrate that SLPI exerts a novel HGF induction and functions as an anti-inflammatory and regenerative factor in addition to its role in protease inhibition.

Is endometriosis an endometrial disease?

Endometriosis is characterised by the presence of abnormally located tissue resembling the endometrium with glands and stroma. Several hypotheses have attempted to explain the development of such tissue. The most often cited theory, that of implantation, proposes that the physiological phenomenon of endometrial reflux in the fallopian tubes during menstruation may, in certain conditions, overcome local defense mechanisms, implant, and proliferate. The implantation theory does not explain why endometriosis will develop only in approximately 10-15% of women, while the reflux of endometrial tissue via the fallopian tubes during menstruation is a quasi-universal phenomenon. The endometrium of women affected by endometriosis could be abnormal compared with endometrium of healthy women. The abnormal endometrium could be able to protect itself from harmful effects of immune cells by expressing specific antigens, by harbouring a different immune cell population and by synthetizing and secreting immunosuppressive factors. Several others characteristic features of endometrium have been described in women with endometriosis: (1) production of its own estrogens in too heavy amount; (2) aptitude for setting up on peritoneum; (3) tendencies to proliferate and to invade tissue; (4) aggressiveness for the peritoneum; (5) auto-protection from physiological apoptosis; (6) abnormal expression of heat shock proteins; and (7) excessive angiogenesis.

Enhanced expression of hepatocyte growth factor by pulmonary ischemia-reperfusion injury in the rat

Hepatocyte growth factor (HGF) has recently been noted to function as a pulmotrophic factor for lung regeneration. The present study was conducted to determine if HGF would be induced in a rat model of pulmonary ischemia-reperfusion (IR) injury, which was established by occlusion of the left lung, and to examine the significance of HGF in subsequent lung repair. The sham-operated rats underwent simple thoracotomy in which the lung was not clamped. We measured the plasma and the tissue levels of HGF by enzyme-linked immunosorbent assays, and the expression of HGF mRNA by Northern blotting. The plasma HGF level was markedly elevated after pulmonary ischemia and reached the peak value on the third postoperative day, being 5-fold higher than that of the sham-operated rats. HGF mRNA expression and the tissue HGF levels were augmented twofold in the ischemic reperfused lung. Immunohistochemical analysis revealed that the infiltrating alveolar macrophages were intensely stained for HGF. DNA synthesis of alveolar epithelial cells, as identified by proliferating cell nuclear antigen (PCNA) staining, was 3-fold higher in the reperfused lung than in the sham-operated lung. Notably, HGF-neutralizing treatment with an anti-HGF antibody reduced DNA synthesis of alveolar epithelial cells in the reperfused lung and aggravated lung injury. This study shows that HGF was induced in the ischemic reperfused lung and may play an important role in regeneration of an injured lung after pulmonary IR.

The repressive function of AP2 transcription factor on the hepatocyte growth factor gene promoter

Hepatocyte growth factor is an important multifunctional growth factor whose gene expression is tightly regulated at the transcriptional level. Previous studies from our laboratory have shown that several cis-acting elements are present in the promoter and proximal promoter region of the HGF gene. In this study, we have uncovered that AP2 transcription factor specifically binds to a regulatory site located at -230 to -260 in the upstream region of the HGF gene promoter. Gelshift and supershift assays confirmed that AP2 has high binding affinity to this region. Functional studies which introduced a mutation in the AP2 core binding region as well as cotransfection experiments using an AP2 expression vector revealed that AP2 exerts a repressive role on the HGF gene promoter activity. The AP2 binding site overlaps with those of NF1 and USF/E-box binding sites which we have recently shown to constitute a composite multifunctional docking site for the members of the NF1 and USF transcription factor families. An inverse correlation was noted between AP2 binding activity to this composite site and HGF gene expression in different cell lines. Therefore, AP2-mediated repression of the HGF gene promoter may be part of the molecular mechanism responsible for regulating HGF expression.

Differential expression of hepatocyte growth factor and its receptor (c-Met) in a rat artificial anus model

Hepatocyte growth factor is a multifunctional polypeptide that has been implicated in cancer growth, tissue development and wound repair. It is mainly synthesized in mesenchymal cells and acts on epithelial cells, where its actions are dependent on binding to a specific cell-surface hepatocyte growth factor receptor (c-Met). In an artificial anus, two different types of epithelial cells (ductal cells of the colon and squamous cells of the skin) intermingle with each other. In the present study, we examined the localization of hepatocyte growth factor and c-Met during the process of repair in a rat artificial anus model, and attempted to clarify the cell types that express hepatocyte growth factor or c-Met messenger RNA by in situ hybridization. Western blot analysis revealed abundant localization of the mature form of hepatocyte growth factor in artificial anal tissues. Moderate hepatocyte growth factor immunoreactivity was noted in regenerated squamous cells in the skin and colonic ductal cells, and strong expression in macrophages and fibroblasts. Moderate c-Met immunoreactivity was present in regenerated epithelial cells in the skin and colon. Throughout the repair process, hepatocyte growth factor and c-Met immunoreactivities were more prominently localized in the squamous cells of the skin than in colonic ductal cells. Competitive reverse transcription-polymerase chain reaction analysis revealed that hepatocyte growth factor mRNA was maximal on day 14 after the operation; however, c-Met mRNA expression had two peaks, on day 1 and day 7. Hepatocyte growth factor mRNA was expressed more in the stromal fibroblasts, macrophages and endothelial cells, and c-Met mRNA was predominant in regenerated squamous cells of the skin. These findings suggest the possibility that hepatocyte growth factor may act in a paracrine manner to mainly enhance the growth of squamous cells of the skin and to a lesser extent the ductal cells of the colon in the artificial anus.

Plasma human hepatocyte growth factor concentrations in patients with biliary obstruction

BACKGROUND

It has been suggested that human hepatocyte growth factor (hHGF) maintains the growth and viability of hepatocytes and biliary epithelial cells. The purpose of this study was to determine plasma hHGF concentrations in patients with obstructive jaundice and to correlate these findings with clinical outcome.

METHODS

The study included 22 patients who had biliary obstruction and underwent percutaneous transhepatic biliary drainage. The plasma concentrations of hHGF, standard liver function tests, daily bile flow and the half-life of serum total bilirubin were measured following the drainage.

RESULTS

Plasma hHGF concentrations were significantly higher in patients with biliary obstruction compared with a control group (P<0.01). The plasma hHGF concentrations correlated with white cell count, prothrombin time and bilirubin half-life (P<0.05), but not with the values from other liver function tests. Seven patients who died within 3 months after biliary drainage had significantly higher concentrations of plasma hHGF than the 15 patients who survived for at least 3 months (P<0.05). The patients who experienced a poor outcome also had lower bile flows and prolonged bilirubin half-lives compared with the survivors (P<0.05). The plasma hHGF concentrations decreased significantly after biliary drainage in the survivors (P<0.01), but not in the patients with a poor outcome.

CONCLUSIONS

These results suggest that systemic inflammation and the hepatic dysfunction caused by obstructive jaundice cause an increase in the plasma concentrations of hHGF. In addition, the plasma concentrations of hHGF may be a predictor of poor outcome in jaundiced patients.

Hepatocyte growth factor and invasion-stimulatory activity are induced in pleural fluid by surgery in lung cancer patients

Hepatocyte growth factor (HGF) is a stromal cell-derived cytokine that can stimulate matrix invasion by carcinoma cells. We analysed the concentrations of HGF and invasion-stimulatory activity in pleural fluid after lung surgery. The concentration of HGF in pleural fluids was measured by enzyme-linked immunosorbent assay in seven patients who underwent pulmonary resection for primary or metastatic lung cancer. The effect of the pleural fluid on cancer cell invasion across reconstituted basement membrane (Matrigel) was assessed with a Boyden chamber assay using a lung adenocarcinoma cell line, A549. HGF levels in the pleural fluid after lung surgery ranged from 6.0 to 23.0 ng ml(-1) (average: 10.2 +/- 4.3 ng ml(-1)). The matrix invasion of lung carcinoma cells in the presence of the pleural fluid was significantly higher than that in the presence of culture medium alone or sera from normal subjects (P < 0.01). The invasion-stimulatory activity of the pleural fluid was strongly inhibited by HGF-neutralizing antibody. Positive correlation was found between the HGF level and invasion-stimulatory activity in the pleural fluids and normal sera (P = 0.0073). This is the first report demonstrating that the lung surgery induces a considerable amount of HGF, which is closely correlated with the invasion-stimulatory activity of the pleural fluid.

Adrenergic stimulation of hepatocyte growth factor expression

Hepatocyte growth factor (HGF), a potent mitogen, is released into plasma at increased levels following injury to certain tissues, including the liver. Early increases in plasma HGF are not due to a release from the injured liver, but rather from distal organs, particularly the lung. We have investigated the ability of norepinephrine (NE), which rises rapidly in plasma after liver resection, to trigger elevated production of HGF in MRC-5 human embryonic lung fibroblasts. Levels of HGF released to culture media and of HGF mRNA increased when cultures were exposed to NE, or to other adrenergic agonists. While stimulation of either beta- or alpha(1)-adrenergic receptors increased HGF expression, responses to NE appear to be mediated primarily via beta receptors. Since NE has already been shown to act as a comitogen with HGF, our findings suggest that adrenergic hormones may act both to induce production of HGF at distal sites, and to enhance the response to HGF at target tissues.

Expression of hepatocyte growth factor in cultured human endometrial stromal cells is induced through a protein kinase C-dependent pathway

To examine the production of hepatocyte growth factor (HGF) by human endometrial stromal cells (ESC) in vitro, concentrations of HGF in the culture media of ESC were measured after the addition of various amounts of 12-O-tetradecanoylphorbol 13-acetate (TPA), forskolin, lipopolysaccharide (LPS), interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor alpha (TNFalpha), interferon-gamma (IFNgamma), or ethynylestradiol-17alpha using an ELISA. The expression of HGF mRNA was also assayed by a reverse transcription-polymerase chain reaction. The concentration of HGF in the culture media of unstimulated ESC was below the detection level of the assay. TPA stimulated the secretion of HGF by ESC in a dose-dependent manner. TPA also induced the transcription of HGF mRNA by ESC. Forskolin, LPS, IL-1beta, IL-6, IL-8, TNFalpha, IFNgamma, or ethynylestradiol-17alpha did not alter HGF mRNA or protein levels. TPA-stimulated production of HGF was partially inhibited by the addition of 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine or sphingosine. These results suggest that a protein kinase C-dependent pathway may play an important role in the regulation of HGF production by ESC. HGF secreted by ESC may be involved in the regeneration of the endometrium during the normal menstrual cycle.

Nonsteroidal anti-inflammatory drugs may prevent colon cancer through suppression of hepatocyte growth factor expression

Nonsteroidal anti-inflammatory drugs which inhibit cyclooxygenase have been reported to suppress colon carcinogenesis. However the mechanism has not yet been elucidated. Growth factors such as hepatocyte growth factor, which are produced by fibroblasts, have been shown to be important in carcinogenesis and the progression of various human cancers. In the present study, we tested the hypothesis that nonsteroidal anti-inflammatory drugs inhibit hepatocyte growth factor expression through an endogenous prostaglandin-mediated pathway in cultured human colonic fibroblasts. Human colonic fibroblasts were obtained from a resected colon and cultured. Hepatocyte growth factor and prostaglandin E2 were measured by enzyme-linked immunosorbent assay. Induction of cyclooxygenase-1 and cyclooxygenase-2 protein was estimated by immunoblotting. Prostaglandins increased hepatocyte growth factor production significantly in a dose- and time-dependent manner. Cholera toxin and 8-bromo cAMP also stimulated hepatocyte growth factor production. Further, prostaglandin E1 significantly increased cellular cAMP. The prostaglandin EP2 and EP4 receptors were detected by reverse transcription-polymerase chain reaction. Interleukin-1beta dramatically increased prostaglandin E2 production and significantly stimulated hepatocyte growth factor synthesis. Interleukin-1beta induced cyclooxygenase-2 but not cyclooxygenase-1 protein. Indomethacin significantly reduced interleukin-1beta-induced prostaglandin E2 release and hepatocyte growth factor production. These results suggest that prostaglandin is a factor for the production of hepatocyte growth factor by human colonic fibroblasts. Nonsteroidal anti-inflammatory drugs may suppress colon carcinogenesis, in part, through the suppression of hepatocyte growth factor expression by inhibiting endogenous prostaglandin production.

Hepatocyte growth factor and the kidney: it is not just for the liver

Mesenchymal-epithelial interactions are important for many biological processes in epithelial organs such as the kidney. Hepatocyte growth factor (HGF) is a mesenchymally derived polypeptide cytokine that acts through its tyrosine kinase c-met receptor and is an important mediator of these interactions. This article reviews data showing the in vitro actions of HGF on renal epithelial cells that result in such diverse responses as mitogenesis, motogenesis, and morphogenesis. It also examines the in vivo evidence linking HGF and the c-met receptor to kidney development, regeneration following injury, and renal disease. Elucidating cellular mechanisms underlying the coordinated control of diverse HGF-induced phenotypic changes in renal epithelia in vitro should contribute to a clearer understanding of complex biological processes such as organogenesis, regeneration, and carcinogenesis in epithelial organs such as the kidney.

Stimulation of hepatocyte growth factor production by ascorbic acid and its stable 2-glucoside

Hepatocyte growth factor (HGF), a cytokine which is generally produced by mesenchymal cells, has mitogenic, motogenic and morphogenic activities in epithelial cells and it also has tumor-suppressing activities. Induction of HGF production may be involved in organ regeneration, wound healing and embryogenesis. We examined the effects of ascorbic acid (AsA), which stimulates the proliferation of fibroblasts, and its stable derivative, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G), on HGF production by human skin fibroblasts. Basal HGF secretion was significantly stimulated by more than 0.1 mM AsA or AA-2G. Both vitamins synergistically enhanced HGF secretion stimulated by growth factors such as epidermal growth factor (EGF), platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF), cholera toxin and other inducers. Induction by EGF or bFGF was most markedly potentiated by the vitamins. HGF production by the KG-1 human leukemia cell line was also augmented by AsA or AA-2G. Another stable AsA derivative, ascorbic acid 2-phosphate (AA-2P) effectively promoted basal and EGF-induced HGF secretion by the fibroblasts, but ascorbic acid 2-sulfate (AA-2S) was much less effective. Intracellular AsA levels increased after the addition of AA-2G and AA-2P as well as AsA, but not after AA-2S. The effect of AA-2G was completely abrogated by the simultaneous addition of castanospermine, an alpha-glucosidase inhibitor, suggesting that the active form of AA-2G is AsA. Constitutive and EGF-induced HGF gene expression was also up-regulated after adding AsA or AA-2G to the cells. These results indicated that AsA acts alone or in synergy with several inducers to stimulate the production and gene expression of HGF in human skin fibroblasts and that the stable AsA derivative AA-2G is as effective as AsA in promoting HGF production.

Developmental and hormonal regulation of hepatocyte growth factor expression and action in the bovine ovarian follicle

Ovarian hormones (i.e., estrogen and LH) may promote folliculogenesis by regulating the local production of mesenchymal "inducer proteins" that mediate theca cell-granulosa cell interactions. Theca cells produce hepatocyte growth factor (HGF) that can stimulate granulosa cell growth. In order to investigate the physiological role of HGF in the ovarian follicle, the developmental and hormonal regulation of HGF was examined during follicular development in the bovine ovary. Reverse transcription-polymerase chain reaction (RT-PCR) analysis was used to examine HGF expression in theca cells and the HGF receptor (HGFR or c-met) in granulosa cells. Both HGF and HGFR were detected throughout follicular development in small (< 5 mm)-, medium (5-10 mm)-, and large (> 10 mm)-sized follicles. Steady-state levels of HGF and HGFR mRNAs were determined using sensitive quantitative RT-PCR assays. Developmental regulation of HGF in theca cells and HGFR in granulosa cells was analyzed in freshly isolated small-, medium-, and large-sized follicles. Observations demonstrate that expression of HGF (in theca cells) and HGFR (in granulosa cells) was highest in large-sized follicles. Hormonal regulation of HGF was analyzed in hormone-treated theca cell cultures. Steady-state levels of HGF mRNA in theca cells were increased by treatment with hCG (an LH agonist), but estradiol had no effect. These results suggest that LH may promote ovarian follicular growth (i.e., granulosa cell proliferation) in part by stimulating the local production of HGF by theca cells. Effects of HGF on granulosa cell differentiated functions were examined. Treatment with HGF reduced basal and FSH-stimulated levels of aromatase activity in bovine and rat granulosa cells. In addition, HGF inhibited the ability of hCG to stimulate progesterone production by granulosa cells. The inhibition of granulosa cell steroid production by HGF is proposed to be the indirect effect of promoting cellular proliferation. Therefore, HGF directly stimulates granulosa cell proliferation and indirectly inhibits granulosa cell differentiated functions. The developmental and hormonal regulation of HGF and HGFR during folliculogenesis provides evidence that HGF may be important for hormone-induced granulosa cell proliferation. As a result, HGF may be essential for establishing the granulosa cell population and microenvironment required for oocyte maturation in the female.

Transforming growth factor alpha levels in liver and blood correlate better than hepatocyte growth factor with hepatocyte proliferation during liver regeneration

Transforming growth factor alpha (TGFalpha) and hepatocyte growth factor (HGF) are mitogens for hepatocytes in vitro and in vivo, produced by hepatocytes or nonparenchymal cells such as stellate cells in the liver. It is still uncertain whether TGFalpha and HGF are essential for liver regeneration. To assess the role of these growth factors in liver regeneration, their circulating and hepatic levels were studied in various rat models of liver regeneration. Hepatic and plasma HGF levels were increased with increased number of mitotic hepatocytes in rats after partial hepatectomy or carbon tetrachloride intoxication. However, hepatic HGF levels were decreased despite an increased number of mitotic hepatocytes and increased or unchanged plasma HGF levels in rats given phenobarbital and in rats after dimethylnitrosamine intoxication, which can induce hepatic necrosis after apoptosis of hepatic stellate cells. In contrast, hepatic and serum TGFalpha levels were increased in all of the models. In sham-operated rats with no increased number of mitotic hepatocytes, hepatic and circulating levels of HGF were increased, whereas those levels of TGFalpha were unchanged. The results indicate that TGFalpha levels in liver and blood more closely correlate with hepatocyte mitogenesis than HGF levels.

Hepatocyte growth factor in human breast milk

PROBLEM

The purposes of this study were to investigate the presence of hepatocyte growth factor (HGF) in human milk, to identify the cells that produce HGF in human milk, and to determine the contribution of HGF to the growth of neonates.

METHOD OF STUDY

The HGF concentrations in serum and whey were determined with an enzyme-linked immunosorbent assay kit. The presence of HGF in whey was also examined by Western blot analysis. To determine which cells in human milk produce HGF, an immunohistochemical examination was conducted. The expression of HGF mRNA in the mononuclear cells in human milk was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). The effects of whey and of recombinant HGF (rHGF) on DNA synthesis by a rat small intestinal cell line, IEC-6, were examined by [3H]thymidine uptake.

RESULTS

Human colostrum whey contained 2.22 +/- 1.02 ng of HGF/ml. Milk whey collected 1 month later contained 1.83 +/- 1.03 ng of HGF/ml. The presence of the heterodimeric form of HGF in colostrum whey was demonstrated by Western blot analysis. HGF was detected in the cytoplasm of human milk macrophages by an immunohistochemical examination, and the RT-PCR also revealed that HGF mRNA is expressed in the mononuclear cells of human milk. DNA synthesis by IEC-6 cells was increased by rHGF treatment and by whey treatment. The effect of whey on DNA synthesis by IEC-6 cells was partially, but significantly, decreased by anti-human HGF-neutralizing antibody treatment.

CONCLUSIONS

Human milk contains a large amount of the active form of HGF, produced by macrophages, and HGF in human milk induces the growth of intestinal cells. Our data suggest that HGF in human milk is one of the important factors regulating the growth of intestinal cells in neonates after birth.

Effect of sofalcone on the expression of hepatocyte growth factor (HGF) and a brief review of HGF in the stomach

Previous studies of hepatocyte growth factor (HGF) in the stomach are briefly reviewed. Exogenous HGF has a strong effect on proliferation and migration of gastric epithelial cells. These effects of HGF are mediated by the specific receptor c-MET. Our previous immunohistochemical study revealed that the main source of endogenous HGF in human gastric ulcer is gastric fibroblasts. These findings suggest that HGF may play an important role in the repair of gastric ulcers through a paracrine mechanism. Therefore, regulation of HGF expression by gastric fibroblasts may be important. We have demonstrated that prostaglandins (PGs) E1 and E2 strongly stimulate HGF expression by gastric fibroblasts, indicating that the clinical efficacy of PGs is mediated by HGF, PGE1 actually facilitates restitution in an in vitro gastric mucosal model consisting of gastric epithelial cells and fibroblasts, which was completely inhibited by anti-HGF antibody. In this study we investigated the effect of an anti-ulcer drug, sofalcone, on PGE2 release and HGF expression by human gastric fibroblasts in primary culture. Sofalcone induced PGE2 release by human gastric fibroblasts in a dose-dependent manner. It also stimulated HGF expression by gastric fibroblasts, indicating that PGs induced by sofalcone increased HGF expression. These findings suggest that clinical efficacy of PGs and sofalcone might be mediated, at least in part, by HGF.

Induction of hepatocyte growth factor/scatter factor by interferon-gamma in human leukemia cells

Induction of hepatocyte growth factor/scatter factor (HGF/SF) may be one of the critical steps in organ regeneration, wound healing, and embryogenesis. We previously reported the production of HGF/SF from various human leukemia cell lines and a high level of the growth factor in blood and bone marrow plasma from patients with various types of leukemia. We determined here the effects of hematopoietic cytokines on HGF/SF production in human leukemia cell lines, KG-1, a myeloid cell line, and RPMI-8226, a B cell line. Interferon (IFN)-gamma remarkably stimulated HGF/SF production in both cell lines at concentrations of more than 0.1 or 1 IU/ml. IFN-alpha and IFN-beta were as effective as IFN-gamma in RPMI-8226 cells, but less than IFN-gamma in KG-1 cells. HGF/SF gene expression in KG-1 cells was also up-regulated by IFN-gamma. Granulocyte colony-stimulating factor (G-CSF), granulocyte/macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-5 and IL-6 had no effect on HGF/SF production in the 2 leukemia cell lines. We also determined the effects of HGF/SF inducers known for human fibroblasts on the growth factor production in leukemia cells. Out of phorbol 12-myristate 13-acetate (PMA), cholera toxin, IL-1 beta, and tumor necrosis factor (TNF)-alpha, the former three were as effective as IFN-gamma in KG-1 cells, but only TNF-alpha stimulated HGF/SF production in RPMI-8226 cells, whose effect was less than those of IFN-alpha, IFN-beta, and IFN-gamma. The effect of IFN-gamma in KG-1 cells was synergistic with that of PMA. In contrast with the effect in leukemia cells, HGF/SF induction by IFN-gamma in human skin fibroblasts was much less than that by PMA or cholera toxin. These results indicated that IFN-gamma is a potent inducer of HGF/SF in human leukemia cells. This finding suggests the presence of a homeostatic control mechanism in liver regeneration and repair: hepatic injury, DNA synthesis inhibition, or apoptosis caused by IFN-gamma is subsequently overcome by cytokine-induced HGF/SF, a potent promoter of liver DNA synthesis.

Differential regulation of keratinocyte growth factor and hepatocyte growth factor/scatter factor by different cytokines in human corneal and limbal fibroblasts

Corneal epithelial stem cells and transient amplifying cells are located in the limbal and corneal regions, respectively. In a serum-free medium with or without different cytokines, limbal fibroblasts consistently produced greater levels of keratinocyte growth factor (KGF) transcript and protein than corneal fibroblasts, whereas corneal fibroblasts produced greater levels of hepatocyte growth factor/ scatter factor (HGF/SF) transcript and protein than limbal fibroblasts. Expression of HGF/SF transcript and protein was up-regulated mildly by epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), or platelet-derived growth factor B (PDGF-BB) but markedly by interleukin-1 beta (IL-1 beta) and was more pronounced in limbal than in corneal fibroblasts. Expression of KGF transcript was down-regulated by EGF, TGF-alpha, and PDGF-BB, was markedly up-regulated by IL-1 beta, and was more pronounced in limbal than in corneal fibroblasts. Expression of KGF protein was up-regulated markedly by IL-1 beta and moderately by PDGF-BB, especially in limbal fibroblasts. TGF-beta 1 uniquely turned off transcript and protein expression of HGF/SF and KGF in corneal fibroblasts. Although its transcript levels were similarly down-regulated in limbal fibroblasts, KGF protein levels were paradoxically up-regulated by TGF-beta 1 when added alone or with TGF-alpha or IL-1 beta. These data indicate that KGF and HGF/SF, two fibroblast-derived epithelial mitogens, are expressed differentially by limbal and corneal fibroblasts and are modulated by cytokines activated during epithelial-mesenchymal interactions, suggesting that they may play a different role in modulating corneal epithelial stem cells and transient amplifying cells.

Increased secretion of hepatocyte growth factor by eutopic endometrial stromal cells in women with endometriosis

OBJECTIVE

We evaluated the secretion of hepatocyte growth factor by eutopic endometrial stromal cells in vitro.

DESIGN

Eutopic endometrial stromal cells were isolated and the culture supernatants were collected after 48 hours of incubation. The secretion of hepatocyte growth factor was analyzed by ELISA.

SETTING

Department of Obstetrics and Gynecology of Tohoku University Hospital.

PATIENT(S)

Specimens of endometrium in the proliferative phase were excised from 11 patients who were undergoing laparoscopy for infertility. Six of the patients had endometriosis and five did not. None of the patients had received hormonal treatment before surgery.

RESULT(S)

Hepatocyte growth factor secretion was found to be increased significantly in cultured endometrial stromal cells from the infertile patients with endometriosis compared with those without endometriosis.

CONCLUSION(S)

The secretion of hepatocyte growth factor was up-regulated in eutopic endometrial stromal cells from patients with endometriosis. An increase in hepatocyte growth factor production may be characteristic of endometriosis and may be involved in the pathophysiology of this disease.

Enhanced expression of hepatocyte growth factor/c-Met by myocardial ischemia and reperfusion in a rat model

BACKGROUND

Hepatocyte growth factor (HGF) is a multifunctional factor implicated in tissue regeneration, wound healing, and angiogenesis. Circulating HGF is reportedly elevated during the early stage of myocardial infarction. However, its precise effect on the heart is unknown. To evaluate the regulation of HGF in ischemically damaged myocardium, the production of HGF and its high-affinity receptor, c-Met, was studied in a rat model of myocardial ischemia and reperfusion.

METHODS AND RESULTS

The plasma concentration of HGF began to increase within 1 hour of reperfusion after 1 hour of ischemia. The peak level was reached at 3 hours after reperfusion. Northern blotting revealed that HGF mRNA expression in the heart was augmented threefold at 24 and 48 hours and remained elevated by twofold at 120 hours after the myocardium was reperfused. The signal for c-met, high-affinity HGF receptor mRNA, was also upregulated parallel to upregulation for HGF. In the kidney, liver, lung, and spleen, HGF mRNA was also maximally increased at 12 hours after reperfusion. However, c-met was not upregulated in these organs. Immunohistochemical studies disclosed that capillary endothelial and interstitial cells, including infiltrating macrophages, were intensely stained for HGF, whereas capillary endothelial cells in the reperfused myocardium were positive for c-Met.

CONCLUSIONS

This study is the first to show that myocardial ischemia and reperfusion induced HGF expression in various organs in vivo. These results indicate that HGF/c-Met plays a role in capillary endothelial cell regeneration in the ischemically injured heart.

Costimulation with ultraviolet B and interleukin-1 alpha dramatically increase tumor necrosis factor-alpha production in human dermal fibroblasts

Ultraviolet light, particularly in wavelengths of 290-320 nm (UVB), is known to induce cytokine synthesis in the skin. Cytokines act in a cascade fashion and can have synergistic or antagonistic actions on regulation of other cytokines. In this study, we sought to determine whether cotreatment with UVB and interleukin-1 alpha (IL-1 alpha) induces tumor necrosis factor-alpha (TNF-alpha) production synergistically by human dermal fibroblasts. UVB irradiation (200 J/m2) or IL-1 alpha (10 ng/ml) independently induced small amount of TNF-alpha (< 25 pg/ml) from human dermal fibroblasts. However, combined treatments with UBV and IL-1 alpha induced 30-40-fold higher levels of TNF-alpha (750 pg/ml) than with either UVB of IL-1 alpha treatment alone. This synergy was also seen with mRNA expression. Maximum synergistic effect was observed when IL-1 alpha was added immediately after irradiation. Considering the fact that UVB is capable of causing release of IL-1 alpha from human keratinocytes and approximately 10% of incident UVB penetrates to the level of dermal fibroblasts, our results suggest that UVB may act in a cascade fashion to induce inflammation by initial release of keratinocyte IL-1 alpha, which then synergizes with UVB on human dermal fibroblasts to significantly increase TNF-alpha production.

Hepatocyte Growth Factor Is Constitutively Produced by Human Bone Marrow Stromal Cells and Indirectly Promotes Hematopoiesis

Bone marrow (BM) stromal cells are required for normal hematopoiesis. A number of soluble factors secreted by these cells that mediate hematopoiesis have been characterized. However, the mechanism of hematopoiesis cannot be explained solely by these known factors, and the existence of other, still unknown stromal factors has been postulated. We showed that hepatocyte growth factor (HGF ) is one such cytokine produced by human BM stromal cells. BM stromal cells were shown to constitutively produce HGF and also to express the c-MET/HGF receptor. The production of HGF was enhanced by addition of heparin and phorbol ester. Dexamethasone and tumor growth factor-β (TGF-β) inhibited the production of HGF. Interleukin-1α (IL-1α) tumor necrosis factor-α (TNF-α), and N6,2′-o-dibutyryl-adenosine-3′:5′-cyclic monophosphate (dbc-AMP) showed no obvious influence on HGF production. Western blot analysis of HGF derived from BM stromal cells showed two bands at 85 and 28 kD corresponding to native and variant HGF, respectively. Addition of recombinant HGF significantly promoted the formation of burst-forming unit-erythroid (BFU-E) and colony-forming unit-granulocyte erythroid macrophage (CFU-GEM) by BM mononuclear cells in the presence of erythropoietin and granulocyte-macrophage colony-stimulating factor (GM-CSF ), but the formation of CFU-GM was not modified. However, HGF had no effects on colony formation by purified CD34+ cells. Within BM mononuclear cells, c-MET was expressed on a proportion of cells (CD34−, CD33+, CD13+, CD14+, and CD15+), but was not found on CD34+ cells. We conclude that HGF is constitutively produced by BM stromal cells and that it enhances hematopoiesis. In addition, expression of c-MET on the stromal cells suggests the presence of an autocrine mechanism, operating through HGF, among stromal cells.

Hepatocyte Growth Factor Is Constitutively Produced by Human Bone Marrow Stromal Cells and Indirectly Promotes Hematopoiesis

Bone marrow (BM) stromal cells are required for normal hematopoiesis. A number of soluble factors secreted by these cells that mediate hematopoiesis have been characterized. However, the mechanism of hematopoiesis cannot be explained solely by these known factors, and the existence of other, still unknown stromal factors has been postulated. We showed that hepatocyte growth factor (HGF ) is one such cytokine produced by human BM stromal cells. BM stromal cells were shown to constitutively produce HGF and also to express the c-MET/HGF receptor. The production of HGF was enhanced by addition of heparin and phorbol ester. Dexamethasone and tumor growth factor-β (TGF-β) inhibited the production of HGF. Interleukin-1α (IL-1α) tumor necrosis factor-α (TNF-α), and N6,2′-o-dibutyryl-adenosine-3′:5′-cyclic monophosphate (dbc-AMP) showed no obvious influence on HGF production. Western blot analysis of HGF derived from BM stromal cells showed two bands at 85 and 28 kD corresponding to native and variant HGF, respectively. Addition of recombinant HGF significantly promoted the formation of burst-forming unit-erythroid (BFU-E) and colony-forming unit-granulocyte erythroid macrophage (CFU-GEM) by BM mononuclear cells in the presence of erythropoietin and granulocyte-macrophage colony-stimulating factor (GM-CSF ), but the formation of CFU-GM was not modified. However, HGF had no effects on colony formation by purified CD34+ cells. Within BM mononuclear cells, c-MET was expressed on a proportion of cells (CD34−, CD33+, CD13+, CD14+, and CD15+), but was not found on CD34+ cells. We conclude that HGF is constitutively produced by BM stromal cells and that it enhances hematopoiesis. In addition, expression of c-MET on the stromal cells suggests the presence of an autocrine mechanism, operating through HGF, among stromal cells.

The differential expression of hepatocyte growth factor and met in human placenta

Met is the tyrosine kinase receptor for the ligand hepatocyte growth factor (HGF). Met/HGF plays an important role in epithelial cell proliferation, migration, and morphogenesis. HGF also plays a crucial role in placental development in the mouse. To determine whether HGF potentially has a similar role in human placental development, the production and localization of Met and HGF were determined in early second trimester and term placentas. Reverse transcription-PCR using specific primers demonstrated the expression of Met and HGF messenger ribonucleic acid in placental villi. HGF production was determined by enzyme-linked immunosorbent assay. HGF production over 48 h by second trimester placental villous explants in culture (810 pg/mg total protein x h) was 2.1-fold greater than that in term placental villous explants (380 pg/mg total protein x h; P < 0.01). Isolated trophoblast did not produce HGF, whereas isolated villous core tissues and villous core mesenchymal cells did produce HGF. Interleukin-1 beta treatment of placental villi or coculture of villous core mesenchymal cells with isolated trophoblast cells did not stimulate HGF production. Using immunohistochemistry, HGF localized to the villous core compartment with no localization to the trophoblast. In contrast, Met localized mainly to cytotrophoblast. These findings suggest that HGF produced by the villous core may act in a paracrine fashion to regulate trophoblast development or function through the HGF receptor, Met.

Wild-type but not mutant p53 activates the hepatocyte growth factor/scatter factor promoter

p53 transactivates the expression of a variety of genes by binding to specific DNA sequences within the promoter. We have investigated the ability of wild-type p53 and a non-DNA binding p53 mutant to activate the hepatocyte growth factor/scatter factor (HGF/SF) promoter using chloramphenicol acetyltransferase reporter constructs. We also used deletion sequences of the HGF/SF promoter to identify which regions, if any, were responsible for p53 binding. Our results show that wild-type but not mutant p53 activates the HGF/SF promoter when using -3000 and -755 bp upstream of the HGF/SF gene. This activation is lost when promoter sequences covering -365 and -239 bp are used. Analysis of the DNA sequence between -365 and -755 bp shows one putative p53 half-site with 80% homology to the consensus sequence and another half-site 3 bases downstream of this with 100% homology to the consensus sequence. In contrast to previously identified p53 binding DNA sequences, the downstream half-site is inverted. We propose that the HGF/SF promoter can be activated by wild-type p53 in vivo and that this could be as a result of a novel form of sequence-specific DNA binding.

Hepatocyte growth factor in assessment of acute pancreatitis: comparison with C-reactive protein and interleukin-6

Serum levels of hepatocyte growth factor (HGF), C-reactive protein (CRP), and interleukin-6 (IL-6) were determined at the time of admission in 38 patients with acute pancreatitis. The clinical utility of HGF for the detection of severe pancreatitis and for predicting prognosis, bacterial infection (infected pancreatic necrosis or sepsis), and organ dysfunction (liver, kidney, and lung) during the clinical course of acute pancreatitis was compared with the clinical utility of CRP and IL-6 by analysis of receiver operator characteristic (ROC) curves. The optimum cutoff levels of HGF for severity, prognosis, infection, hepatic dysfunction, renal dysfunction, and respiratory dysfunction were 0.9, 1.1, 1.0, 1.1, 1.1, and 1.0 ng/ml, respectively. HGF was as useful as CRP and more useful than IL-6 for detection of severe pancreatitis and for predicting hepatic dysfunction. Moreover, HGF was more useful than CRP or IL-6 for predicting prognosis, renal dysfunction, and respiratory dysfunction. However, for predicting infection, CRP was more useful than HGF. These results suggest that serum HGF levels on admission may be a useful new clinical parameter for determining the prognosis of acute pancreatitis and that HGF may be closely related to the organ dysfunction of acute pancreatitis.

Involvement of hepatocyte growth factor in increased integrin expression on HepG2 cells triggered by adhesion to endothelial cells

Adhesion of cancer cells to vascular endothelium is an important step in haematogenous metastasis of cancer. A human hepatocellular carcinoma cell line, HepG2, strongly adheres to human umbilical vein endothelial cells (HUVECs) through the interaction of E-selectin and its carbohydrate ligand sialyl Lewis X. In this study, we investigated alteration in integrin expression on HepG2 cells, which follows the selectin-mediated initial adhesion of HepG2 cells to HUVECs. Expression of alpha2beta1 integrin was markedly increased when the HepG2 cells adhered to HUVECs. Among the tested cytokines that are known to be produced by endothelial cells, recombinant hepatocyte growth factor (rHGF) could replace the effect of HUVECs, and a similar increase in integrin expression was observed by the addition of 20 ng ml-1 rHGF to HepG2. The increment of alpha2beta1 integrin expression was significantly inhibited by anti-HGF neutralizing antibody treatment. HepG2 cells expressed alpha2, alpha6, beta1, and beta4 integrin subunits, but expression of integrins other than alpha2beta1 was not affected by the rHGF treatment. The rHGF treatment of HepG2 cells resulted in augmented adhesion to immobilized collagen. This augmentation in adhesion to collagen was completely blocked by the addition of anti-alpha2- or anti-beta1-integrin antibody. In double-chamber chemoinvasion experiments, transmigration of the HepG2 cells through extracellular matrix (ECM) gel was significantly accelerated by co-cultivation with HUVECs. A similar level of enhancement in transmigration activity of the cancer cells was observed by the addition of rHGF. Our interpretation of the results described above is that the cancer cells received stimulation from cytokines, such as HGF, presented by vascular endothelial cells, following the initial adhesion of cancer cells via selectins. This resulted in the secondary increment in the expression of cell adhesion molecules, such as the alpha2beta1 integrin, and led to the augmented adhesive activities of cancer cells towards extracellular matrices at vascular walls. We suggest that this sequence of events is involved in the facilitated migration of some cancer cells to extravascular tissues.

Increased production of interleukin 1 beta and hepatocyte growth factor may contribute to foveolar hyperplasia in enlarged fold gastritis

BACKGROUND AND AIMS

It has been reported that eradication of Helicobacter pylori improves fold width in H pylori associated enlarged fold gastritis. The aim of this study was to clarify the mechanism of fold thickening in this condition.

PATIENTS AND METHODS

In eight patients with enlarged fold gastritis and 13 patients without enlarged folds, the presence of H pylori infection, inflammatory infiltrates, mucosal plasia, and epithelial cell proliferation in the body mucosa were investigated, and production of transforming growth factor alpha (TGF alpha), hepatocyte growth factor (HGF), and interleukin 1 beta (IL 1 beta) was determined by a competitive reverse transcription/polymerase chain reaction method and in vitro short-term culture of biopsy specimens.

RESULTS

In the patients with enlarged fold gastritis, inflammatory infiltrates including macrophages increased with H pylori colonisation in the body. Foveolar thickness and proliferating cell nuclear antigen (PCNA) labelling index were increased. Messenger RNA levels of HGF, but not TGF alpha, were increased, and release of HGF and IL 1 beta was increased. HGF release, which was positively correlated with IL 1 beta release and foveolar thickness, decreased in the presence of IL 1 receptor antagonist. After eradication of H pylori, inflammatory infiltrates, IL 1 beta and HGF release decreased with concomitant decreases in PCNA labelling index, foveolar thickness and fold width.

CONCLUSIONS

Increased IL 1 beta and HGF production caused by H pylori infection may contribute to fold thickening of the stomach by stimulating epithelial cell proliferation and foveolar hyperplasia in patients with enlarged fold gastritis.

Hepatocyte growth factor as a key to modulate anti-ulcer action of prostaglandins in stomach

Although the clinical efficacy of prostaglandins (PGs), especially on gastric mucosal injuries induced by nonsteroidal antiinflammatory drugs, is widely appreciated, their mechanism of action, apart from acid suppression, is quite unclear. In this study, we have established a primary culture system of human gastric fibroblasts and clearly demonstrated that PGs strongly induce the expression of hepatocyte growth factor (HGF) in the fibroblasts, which is mediated by PGE specific receptor, EP2 or EP4. Since HGF facilitates repair and protection of gastric epithelial cells in a paracrine manner, it is assumed that some of the beneficial effects of PGs may be mediated by HGF. To confirm this assumption, we established a simplified in vitro culture gastric mucosal model which consists of gastric epithelial cells and gastric fibroblasts. Using the model, we performed a round wound restitution assay. PGE1 remarkably accelerated restitution which was completely inhibited by anti-HGF antibody, indicating that the action was mediated by HGF. To confirm these in vitro data, we further demonstrated that HGF mRNA expression is downregulated at the edges of nonsteroidal antiinflammatory drug-induced gastric ulcers where PGs should be depleted. In summary, we proposed that gastric fibroblasts are newly recognized targets of PGs, and HGF produced by human gastric fibroblasts may be a key factor for anti-ulcer action of PGs in the stomach.

Interleukin-1-induced growth factor expression in postmitotic and resting fibroblasts

Tissue homeostasis in skin is regulated by epithelial-mesenchymal interactions, mostly operating via diffusible factors. To study the underlying regulatory mechanisms, in vitro systems have been established to mimic the in vivo situation in skin. In co-cultures, keratinocytes grow either adjacent to irradiated fibroblasts on plastic or on top of collagen gels containing fibroblasts, thus forming 3-dimensional organotypic structures. Keratinocyte growth is supported in part by fibroblast-produced factors induced by keratinocyte mediators such as interleukin-1 (IL-1). To better understand this cellular interaction and its modulation by fibroblast proliferation and extracellular matrix (ECM), we examined the effect of IL-1 on growth factor expression in proliferating and growth-arrested x-irradiated human dermal fibroblasts on plastic and in resting cells embedded in collagen gels. By semiquantitative reverse transcriptase PCR, we demonstrated that IL-1alpha and IL-1beta stimulated the expression of KGF, HGF, IL-1alpha, IL-1beta, IL-1RI, and IL-8 in fibroblasts regardless of their physiologic condition, whereas that of TGF-beta remained unaffected. The constitutive mRNA levels were usually lower in irradiated postmitotic and ECM-embedded cells than in proliferating fibroblasts. Cells responded to stimulation with IL-1 under all three culture conditions, although to different degrees depending on the growth factor. As demonstrated for HGF, IL-8, and IL-1beta, the IL-1alpha-induced mRNA expression was followed by production and secretion of protein in irradiated fibroblasts. Thus, our findings show that resting and growth-inhibited fibroblasts, reflecting more closely the situation in dermis, exhibit lower constitutive growth factor expression levels but characteristically respond to IL-1 stimulation.

Interleukin-6 induces proliferation of rat hepatocytes in vivo

BACKGROUND/AIMS

The aim of this study was to assess the effect of interleukin-6 (IL-6) on the proliferation of hepatocytes and to study the interaction between IL-6 and hepatocyte growth factor (HGF) in vivo.

METHODS

IL-6 was injected at a dose of 200 micrograms/mg subcutaneously into rats every day for 14 days. Liver and blood samples were obtained at 1, 3, 7 and 14 days during IL-6 administration. Hepatocyte proliferative activity of sera was measured using 3H-thymidine incorporation into cultured rat hepatocytes. To evaluate the proliferative activity of the hepatocytes in tissue sections, hepatic DNA content and immunostaining of the liver tissue sections for proliferating cell nuclear antigen (PCNA) were performed. Plasma HGF levels were measured using specific EIA. In addition, total RNA was extracted from the liver and expression of HGF mRNA was detected by RT-PCR.

RESULTS

The DNA contents of liver taken from IL-6-treated rats were increased during IL-6 administration compared with untreated rats. Sera taken from IL-6-treated rats at various intervals during administration also significantly increased 3H-thymidine incorporation by cultured rat hepatocytes compared with sera from untreated rats, suppressing 3H-thymidine incorporation at day 1 and 3 by anti-HGF antibody. IL-6 itself did not increase 3H-thymidine incorporation. Increased expression of PCNA in these hepatocytes was noted from 1 day after IL-6 administration, and at 14 days, the number of PCNA-positive cells was sevenfold greater than in the livers of untreated rats. However, plasma HGF levels showed a peak at day 1, decreased gradually from day 3, and became undetectable by day 14. HGF mRNA expression in livers of IL-6-treated rats was suppressed from day 3 to day 14 of IL-6 administration.

CONCLUSIONS

These data show that IL-6 induces an early phase of liver cell growth in vivo and suggest that an increase level of HGF mediates this effect.

Mechanisms of hepatocyte growth factor stimulation of keratinocyte metalloproteinase production

Matrix metalloproteinases participate in normal physiologic processes; however, their overproduction has been associated with connective tissue destruction in a variety of pathological states. Migrating basal keratinocytes transiently express collagenase-1 during normal cutaneous reepithelialization. However, the overexpression of both collagenase-1 and stromelysin-1 has been associated with the pathogenesis of chronic nonhealing ulcers. Aberrant expression of metalloproteinases in inflammation is mediated, at least in part, by soluble factors. Since hepatocyte growth factor/scatter factor (HGF/SF) has been reported to promote keratinocyte migration and proliferation, key events in wound repair, and since HGF/SF is produced by dermal fibroblasts and its c-Met receptor is expressed by basal keratinocytes in wounded skin, we have studied the effects of HGF/SF upon keratinocyte metalloproteinase expression. We have found that HGF/SF can stimulate keratinocyte collagenase-1 and stromelysin-1 production in a dose-dependent and matrix-dependent manner. Expression of 92-kDa gelatinase was not affected by HGF/SF. We determined that HGF/SF regulation of collagenase-1 expression is transcriptionally mediated and requires tyrosine kinase and protein kinase C activaties. HGF/NK1, a naturally occurring, truncated form of HGF/SF, also stimulates collagenase-1 production, but much less efficiently than does the parent molecule. However, HGF/NK2, another HGF/SF splice variant, as well as heparin, potently inhibit HGF/SF-induced collagenase-1 synthesis. These results indicate that HGF/SF and its naturally occurring splice variants have diverse biological effects on keratinocytes and suggest an additional mechanism whereby HGF/SF may regulate keratinocyte function during wound repair.

Interleukin 4 inhibits hepatocyte growth factor-induced invasion and migration of colon carcinomas

Hepatocyte growth factor (HGF) is known to have a number of biological properties including promoting tumor progression of human carcinomas. Metastasis involves a number of events that are attributed to induction by paracrine factors such as HGF. Identification of natural inhibitors of these events would allow better control of tumor progression. Recently we demonstrated that interleukin 4 (IL-4) can regulate proliferation of various human carcinoma cell lines. In the present study, we used established human colon carcinoma cell lines and primary colon carcinoma cell cultures to determine if IL-4 could regulate HGF-induced cell proliferation and other events of tumor progression such as MMP (matrix metalloproteinases)-1, -2, and -9 production, cell migration and cell-matrix invasive activity. All colon carcinoma cell lines expressed HGF and IL-4 receptors. IL-4 significantly inhibited HGF-induced proliferation of one cell line. Cell-matrix invasion was significantly enhanced by HGF (0.1-10 ng/ml); IL-4 (1-10 U/ml) significantly inhibited HGF-induced invasion in a dose-dependent manner. IL-4 also inhibited HGF-induced cell-matrix invasion of metastatic colon carcinoma cells and HGF-induced cell migration. HGF enhanced MMP-1, -2, and -9 production by cell lines. This effect could be inhibited by IL-4. These findings indicate that IL-4 is a potent inhibitor of HGF-induced invasion and metastasis-related functions of human colon carcinoma cells.

Increase in histamine synthesis by liver macrophages in CCl4-injured mast cell-deficient W/Wv mice

This study set out to examine the possible role of liver macrophages in histamine synthesis in the injured liver. The effects of the hepatotoxins Escherichia coli lipopolysaccharide (LPS) and CCl4 on histamine synthesis in the liver of mice were evaluated. C3H/HeJ mice were resistant to LPS in including histidine decarboxylase (HDC) in the liver compared with C3H/HeN mice and mast cell-deficient W/Wv mice. However, C3H/HeJ mice did respond strongly to another hepatotoxin, CCl4, leading to a significant increase in HDC activity. CCl4 also caused a marked increase in HDC activity and histamine levels in the liver of W/Wv mice. In addition, injection of CCl4 produced a large increase in the activity of HDC in the spleen and lung of W/Wv mice. HDC activity was confined to the nonparenchymal cells, with parenchymal cells expressing essentially no HDC activity. The CCl4-induced increase in HDC activity was confined, at least in part, to the liver macrophages. These results indicate that the macrophages are responsible for the increase in HDC-dependent histamine production in the liver caused by the injection of hepatotoxins. The possible role of histamine in liver regeneration after injury is discussed.

Acquisition of invasive phenotype in gallbladder cancer cells via mutual interaction of stromal fibroblasts and cancer cells as mediated by hepatocyte growth factor

Growth and motility of carcinoma cells are regulated through their interactions with host stromal cells, i.e., tumor-stromal interactions. Hepatocyte growth factor (HGF), a ligand for c-Met tyrosine kinase, is a stromal-derived regulator of growth, motility, and morphogenesis. HGF stimulated proliferation and motility of GB-d1 gallbladder carcinoma cells from a patient with gallbladder cancer. HGF induced in vitro invasion of GB-d1 cells into a collagen gel matrix, and this potent, invasive effect was not seen with epidermal growth factor, transforming growth factor-beta 1, basic fibroblast growth factor, or platelet-derived growth factor. Although GB-d1 did not produce HGF, the cells did produce a factor which enhances HGF production in human skin fibroblasts, and this factor proved to be interleukin-1 beta (IL-1 beta). When GB-d1 cells were co-cultured with fibroblasts such that a collagen gel matrix was layered between the GB-d1 cells and fibroblasts, GB-d1 cells invaded the gel, but invasion of the cells in the co-culture system was inhibited by antibodies against HGF and partially inhibited by antibodies against IL-1 beta. Thus, GB-d1 cell-derived IL-1 beta stimulates HGF production in stromal fibroblasts and HGF up-regulated in the fibroblasts induces invasion of GB-d1 cells. The looped interaction of carcinoma cells and stromal fibroblasts mediated by HGF and a HGF-inducer such as IL-1 beta may be one mechanism which would explain the acquisition of malignant phenotype through tumor-stromal interactions.