Hepatocyte growth factor(HGF): a new biochemical marker for acute myocardial infarction

The purpose of this study was to investigate the use of hepatocyte growth factor as a biochemical marker for acute myocardial infarction. Several biochemical markers are used for noninvasive detection of acute myocardial infarction. However, hepatocyte growth factor has not been used previously for this purpose. We measured hepatocyte growth factor, creatine phosphokinase, and MB isoenzyme (CK-MB) levels in 6 patients with stable effort angina after diagnostic catheterization (controls) and in 12 patients with acute myocardial infarction (AMI). The measurements in the AMI patients were recorded twice a day for the first 3 days after onset of chest pain and once a day for the next 4 days. Furthermore, in each patient we evaluated the time to reach the maximum level and the time for the level to decline to less than half the maximum. Hepatocyte growth factor levels (ng/ml) were 0.3+/-0.1 for angina pectoris patients, and 15.7+/-9.1 within 6h and 12.5+/-4.6 within 12h after the onset for AMI patients, respectively. The correlation coefficients between hepatocyte growth factor and creatine phosphokinase and between hepatocyte growth factor and CK-MB were 0.68 and 0.74, respectively. The time to reach the maximum (h) and the time to decline to less than half of the maximum level (days) were 6.6+/-2.6 and 1.2 +/-0.2 for hepatocyte growth factor, 19.4+/-8.7 and 2.5+/-1.4 for creatine phosphokinase, and 16.6+/-7.7 and 1.5+/-0.4 for CK-MB, respectively. Hepatocyte growth factor is useful as a prognostic indicator and reflects the clinical course in patients with acute myocardial infarction.     

Hepatocyte growth factor (HGF/SF) is a muscle-derived survival factor for a subpopulation of embryonic motoneurons

Muscle-derived factors are known to be important for the survival of developing spinal motoneurons, but the molecules involved have not been characterized. Hepatocyte growth factor/scatter factor (HGF/SF) plays an important role in muscle development and motoneuron axon outgrowth. We show that HGF/SF has potent neurotrophic activity (EC50=2 pM) for a subpopulation (40%) of purified embryonic rat motoneurons. Moreover, HGF/SF is an essential component of muscle-derived support for motoneurons, since blocking antibodies to HGF/SF specifically inhibited 65% of the trophic activity of media conditioned by C2/C7 skeletal myotubes, but did not inhibit the trophic activity secreted by Schwann cell lines. High levels of expression of the HGF/SF receptor c-Met in the spinal cord are restricted to subsets of motoneurons, mainly in limb-innervating segments. Consistent with this distribution, cultured motoneurons from limb-innervating brachial and lumbar segments showed a more potent response to HGF/SF than did thoracic motoneurons. By the end of the period of motoneuron cell death, levels of c-Met mRNA in motoneurons were markedly reduced, suggesting that the effects of HGF/SF may be limited to the period of motoneuron cell death. HGF/SF may play an important role during motoneuron development as a muscle-derived survival factor for a subpopulation of limb-innervating motoneurons.     

Hepatocyte growth factor (HGF) in fluid from operation fields of breast surgery

Surfactant protein-A (SP-A) levels are increased in Pneumocystis carinii pneumonia, but the role of SP-A in the pathogenesis of P. carinii pneumonia is not completely understood. This study investigated the effect of SP-A on the in vitro binding and phagocytosis of P. carinii by normal human alveolar macrophages (AM). Determination of binding and phagocytosis was done with a fluorescence-based assay, utilizing fluorescein isothiocyanate (FITC)-labeled P. carinii. Binding and phagocytosis of P. carinii to AM correlated inversely with the levels of SP-A present on the surface of the organisms (r = -0.6323, P = 0.0086; and r = -0.9827, P < 0.0001, respectively). The addition of exogenous SP-A to organisms with low surface-associated SP-A reduced P. carinii binding by 30% (P < 0.05) and reduced phagocytosis by 20% (P < 0.05), whereas this effect was reversed with ethylenediamine tetraacetic acid (EDTA) or anti-SP-A antibody. Furthermore, binding and phagocytosis were enhanced after enzymatic removal of P. carinii surface-associated SP-A, and this effect was reversed with the addition of exogenous SP-A. The observed inhibitory effect of SP-A on P. carinii binding and phagocytosis reflected binding of SP-A to the organisms rather than a direct effect of SP-A on the macrophages. These data suggest that increased levels of SP-A may contribute to the pathogenesis of P. carinii pneumonia through binding to the surface of the organism and interfering with AM recognition of this opportunistic pulmonary pathogen.     

Hepatocyte growth factor may act as a pulmotrophic factor on lung regeneration after acute lung injury

Hepatocyte growth factor (HGF) has been shown to have hepatotrophic and renotropic functions for regeneration of the liver and kidney through its mitogenic, motogenic, and morphogenic properties. To examine the involvement of HGF in lung regeneration after acute injury, we analyzed changes of HGF mRNA, HGF activity, and HGF receptors in the rat lung after lung insult and measured HGF concentration in sera of patients with various lung diseases. Following the onset of acute lung injury induced by intratracheal hydrochloride injection, a compensatory DNA synthesis occurred in the bronchial epithelium with a peak at 24 h and in the alveolar epithelium with a peak at 48 h. Expression of HGF mRNA in the rat lung remarkably increased only 3 h after the treatment and HGF activity in the lung also increased to about 3-fold at 6 h later. HGF receptors in the lung but not in the other noninjured organs were down-regulated 12 h later. These marked increases in HGF mRNA and HGF activity and the concomitant down-regulation of HGF receptor occurred before the marked compensatory DNA synthesis in bronchial and alveolar epithelial cells. HGF concentration in sera of patients with various lung diseases, as measured by radioimmunoassay, was much higher than that in healthy donors. These results suggest that HGF is newly produced in the lung after acute lung injury and may have a role in regeneration of the lung.     

Hepatocyte growth factor activator: a possible regulator of morphogenesis during fetal development of the rat gastrointestinal tract

PURPOSE: Cryosurgical ablation of the prostate is a novel therapeutic modality that induces cell lysis in the prostate by direct application of low temperatures. We have been conducting an ongoing prospective pilot study of the use of cryosurgical prostate ablation in treating patients with nonmetastatic prostate adenocarcinoma since January 1993. Results in 145 consecutive patients with mean 36 months and minimum 12 months of followup are presented. MATERIALS AND METHODS: Accrual was open to patients with clinical stages T1a to T3c prostate adenocarcinoma. Pelvic lymph node dissections were recommended but not required for patients with prostate specific antigen (PSA) greater than 15 ng./ml. before study entry. PSA changes, random prostate biopsy findings and morbidities after cryosurgical prostate ablation were recorded for each patient. RESULTS: Overall actuarial rates at 42 months for maintaining PSA less than 0.3 and less than 1.0 were 59% and 66%, respectively. The overall actuarial progression-free rate at 60 months was 56%. Among 160 biopsies performed 16% showed some evidence of residual carcinoma. Overall crude rates of maintaining either a negative biopsy or PSA less than 0.3 at 6 and 24 months after cryosurgical prostate ablation were 87% and 73%, respectively. Significantly higher morbidities were seen in previously radiated patients undergoing cryosurgical prostate ablation compared to those with no prior radiation. Among nonradiated patients 85% experienced no significant morbidity after cryosurgical prostate ablation. CONCLUSIONS: Although preliminary, short-term outcomes after cryosurgical prostate ablation appear to be comparable to identical outcomes reported for external beam radiotherapy. Based on these results cryosurgical prostate ablation appears to be an effective therapeutic alternative for treating patients with localized prostate adenocarcinoma.     

Androgen regulation of epidermal growth factor receptor binding activity during fetal rabbit lung development

The luteolytic response to a prostaglandin F2 alpha analogue, cloprostenol, was investigated in vivo and in vitro at defined stages of the luteal phase. In vivo administration of cloprostenol to female marmoset monkeys on day 3 after ovulation had no effect on plasma progesterone concentrations, whereas administration on day 14 after ovulation reduced plasma progesterone to preovulatory concentrations within 4 h. To identify the cellular basis for this luteolytic action, marmoset luteal tissue obtained on days 3, 6 and 14 after ovulation was incubated in vitro and progesterone production, cAMP accumulation and phosphoinositide (PI) turnover measured in response to cloprostenol, human chorionic gonadotrophin (hCG) with or without cloprostenol, or dibutyryl-cAMP with or without cloprostenol. Progesterone production was stimulated by both hCG and dbcAMP at all stages of the luteal phase. Although neither hCG nor dbcAMP had any significant effects on PI turnover, hCG also increased cAMP accumulation. In marmoset luteal tissue obtained on day 3 after ovulation, cloprostenol had no significant effect on basal or hCG/dbcAMP-stimulated progesterone production but significantly stimulated PI turnover. In contrast, on days 6 and 14 after ovulation, cloprostenol significantly inhibited hCG- and dbcAMP-stimulated progesterone production and the cAMP response to hCG, but had no significant effect on PI turnover. Since progesterone production by the marmoset corpus luteum depends on the luteotrophic support of luteinizing hormone (LH), these observations suggest that the luteolytic action of cloprostenol in vivo involves the inhibition of LH/hCG action at sites both prior and subsequent to cAMP accumulation. However, such luteolytic effects do not appear to require the generation of inositol phosphates by increased PI turnover.     

Hepatocyte growth factor (HGF) produced by peritoneal fibroblasts may affect mesothelial cell morphology and promote peritoneal dissemination

Mesothelial cell monolayers have been reported to prevent infiltration of cancer cells into the peritoneum. We have previously reported that peritoneal fibrosis induced by gastric cancer cells prior to metastatization may provide a congenial environment for peritoneal metastases. In this study, we investigated the effects of peritoneal fibroblasts on peritoneal mesothelial cell morphology. Human gastric cancer (OCUM-2MD3), peritoneal fibroblast (NF-2P) and mesothelial (MS-1) cell lines were established in our laboratory. Histology of the peritoneum was investigated following intraperitoneal inoculation of serum-free conditioned media (SF-CM) from OCUM-2MD3 cells into nude mice. SF-CM from peritoneal fibroblasts was added to monolayer-cultured mesothelial cells, and their morphology was examined by phase-contrast microscopy. This experiment was conducted in the presence and absence of neutralizing antibodies against various factors. Mesothelial cells exposed to fibroblasts proliferation became hemispherical and separated from each other, while unexposed mesothelium remained as a flat monolayer. Cultured-mesothelial cells rounded up or exhibited a fibroblast-like shape following the addition of peritoneal fibroblast SF-CM. Anti-hepatocyte growth factor (HGF) neutralizing antibody partly inhibited this effect. We suggest that soluble factors, such as HGF, produced by peritoneal fibroblasts affect the morphology of mesothelial cells in monolayers so that the resulting environment may become prone to the peritoneal dissemination of cancer cells.     

Human hepatocyte growth factor (HGF) in the aqueous humor

Previous studies have demonstrated that individuals with cystinosis, an inherited metabolic disorder, have difficulty processing visual information, and may be selectively impaired in the ability to mentally rotate figures, despite having normal IQs and normal primary sensory function. In our novel task-the 'Black Box'-subjects identified objects solely by feeling the contours. Twenty-three subjects with cystinosis, aged 4 to 34 years, were individually matched with controls on age, sex, handedness, and test form. Subjects with cystinosis performed significantly worse in identifying objects than did controls. In addition, when only subjects over 7 years of age were included, those with cystinosis took significantly longer to correctly identify objects than did controls. Our findings suggest that individuals with cystinosis have difficulty with tactile recognition of common objects. These results support the hypothesis that a genetic disorder may have specific behavioral correlates.     

Inhibition of tumor growth and invasion by a four-kringle antagonist (HGF/NK4) for hepatocyte growth factor

Invasion of various carcinoma cells follows their interaction with stromal cells. Hepatocyte growth factor (HGF), four-kringle-containing growth factor, is a mesenchymal or stromal-derived mediator which affects the growth and the invasiveness of carcinoma cells. We now have evidence that a four-kringle-containing antagonist for HGF, HGF/NK4 inhibits invasion of tumors in vivo, as well as in vitro. HGF/NK4 competitively inhibited the binding of HGF to Met/ HGF receptors on GB-d1 human gallbladder carcinoma cells. HGF induced invasion of the cells through Matrigel basement membrane components and into collagen gels, but HGF-induced invasion was inhibited by HGF/NK4. Invasion of GB-d1 cells was induced by co-cultivation with stromal fibroblasts, which mimics tumor-stromal interaction, but it was almost completely suppressed by HGF/NK4. Likewise, invasive growth induced by HGF in collagen gels in GB-dl cells, HuCC-T1 human cholangiocarcinoma cells, and ME-180 human uterus cervical carcinoma cells was also strongly inhibited by HGF/NK4. When GB-d1 cells were implanted subcutaneously into nude mouse, tumor cells invaded muscular tissue, but the infusion of HGF/NK4 inhibited this invasion. Furthermore, HGF/NK4 increased apoptotic cell death of GB-d1 cells and inhibited tumor growth in vivo. These results indicate that HGF/ NK4 may inhibit growth and invasion of carcinoma cells, as mediated by HGF during tumor-stromal interactions. We propose that there is a unique therapeutic potential for HGF/NK4 to prevent tumor invasion and perhaps even metastasis.     

Glycine-extended gastrin acts as an autocrine growth factor in a nontransformed colon cell line

BACKGROUND & AIMS: The hypothesis that progastrin-derived peptides act as autocrine growth factors for colorectal carcinomas has generated considerable interest. However, the influence of autocrine gastrins on nontumorigenic colonic cells has not been investigated. This study tested the above hypothesis in the nontumorigenic, conditionally immortalized mouse colon cell line YAMC. METHODS: The effects of expression of antisense or sense gastrin messenger RNA, treatment with antibodies against progastrin-derived peptides, or treatment with gastrin receptor antagonists on YAMC cell proliferation were measured. RESULTS: YAMC clones expressing antisense gastrin messenger RNA had reduced levels of immunoreactive progastrin-derived peptides and a reduced rate of proliferation, relative to vector only-transfected cells. Glycine-extended gastrin17, but not amidated gastrin17, reversed the antisense-induced inhibition of proliferation and stimulated the proliferation of sense- or vector only-transfected cells. YAMC cells bound 125I-glycine-extended gastrin17 (Kd, 0.36 nmol/L, 1810 sites/cell), but not 125I-amidated gastrin17, and binding was unaffected by gastrin receptor antagonists including benzotript. Proliferation of all YAMC clones was partially inhibited either by an antibody selective for glycine-extended gastrin or by preincubation with benzotript, and the inhibitory effects were additive. CONCLUSIONS: YAMC cells use nonamidated progastrin-derived peptides as autocrine growth factors, partly through binding to an extracellular receptor selective for glycine-extended gastrin, and partly through an intracellular mechanism.     

Interleukin 6 acts as a paracrine growth factor in human mammary carcinoma cell lines

The effect of interleukin 6 (IL-6) on normal and human mammary carcinoma epithelial cells was studied. IL-6 inhibited the growth of estrogen receptor-positive [ER(+)] breast cancer cell lines, which underwent apoptosis with prolonged treatment. In contrast, ER(-) breast cancer cell lines were resistant to IL-6-mediated growth inhibition. By examining the components of the IL-6 receptor (IL-6R) system, we found that ER(+) breast cancer cells expressed predominantly soluble IL-6Ralpha, whereas the ER(-) breast cancer cells expressed primarily the transmembrane form of the IL-6R, gp130. In addition, detectable levels of IL-6 were secreted into the medium by ER(-) but not ER(+) breast cancer cells. Furthermore, the supernatant obtained from IL-6-secreting, ER(-) cells suppressed the growth of IL-6-sensitive, ER(+) breast cancer cells in a paracrine fashion. Although IL-6 is secreted by ER(-) breast cancer cells, this cytokine does not seem to stimulate the proliferation of these cells in an autocrine fashion. These studies indicate that IL-6 can regulate the growth of normal and transformed human mammary epithelial cells differentially, and that IL-6 secretion by some ER(-) breast cancer cells can function as a paracrine growth factor, suppressing the growth of ER(+) breast cancer cells in vitro.     

Hepatocyte growth factor is a coupling factor for osteoclasts and osteoblasts in vitro

Hepatocyte growth factor (HGF), also known as scatter factor, is a powerful motogen, mitogen, and morphogen produced by cells of mesodermal origin, acting on epithelial and endothelial cells. Its receptor is the tyrosine kinase encoded by the c-MET protooncogene. We show that the HGF receptor is expressed by human primary osteoclasts, by osteoclast-like cell lines, and by osteoblasts. In both cell lineages, HGF stimulation triggers the receptor kinase activity and autophosphorylation. In osteoclasts, HGF receptor activation is followed by increase in intracellular Ca2+ concentration and by activation of the pp60c-Src kinase. HGF induces changes in osteoclast shape and stimulates chemotactic migration and DNA replication. Osteoblasts respond to HGF by entering the cell cycle, as indicated by stimulation of DNA synthesis. Interestingly, osteoclasts were found to synthesize and secrete biologically active HGF. These data strongly suggest the possibility of an autocrine regulation of the osteoclast by HGF and a paracrine regulation of the osteoblast by the HGF produced by the osteoclast.     

Hepatocyte growth factor/scatter factor overexpression induces growth, abnormal development, and tumor formation in transgenic mouse livers

To investigate the in vivo role of hepatocyte growth factor/scatter factor (HGF/SF) in liver function, we generated transgenic mice using a mouse HGF/SF cDNA under the control of the mouse metallothionein gene promoter and 5'/3' flanking sequences. In adult HGF/SF transgenic mice, liver weight as a percentage of total body weight was at least twice that of wild-type mice. Comparison of transgenic and control liver morphology revealed dramatic heterogeneity in the size and appearance of hepatocytes as a distinctive feature of HGF/SF overexpression. Transgenic livers exhibited a significant increase in the number of small hepatocytes with a 2N DNA content, accounting for the observed increase in liver mass. The DNA labeling index of hepatocytes increased 11-fold at 4 weeks of age, when liver enlargement first became apparent, and was still elevated about 5-fold in adult HGF/SF transgenic mice. Moreover, hepatocytes isolated by perfusion of transgenic livers doubled every 2 days in culture, whereas little or no growth was observed with isolated control hepatocytes. The mechanistic basis of hepatocyte proliferation was elucidated as the chronic activation of the c-met proto-oncogene product. Met and substrates such as phosphatidylinositol 3-kinase, Src homology and collagen-like, pp60c-src, focal adhesion kinase p125FAK, and paxillin were associated with tyrosine-phosphorylated complexes in a hepatocyte cell line established from the transgenic liver. This proliferative stimulus triggered the formation of hepatocellular adenomas and/or carcinomas in most transgenic mice > or = 1.5 years of age. Finally, the rate of transgenic mouse liver regeneration was increased 3-fold over control livers following partial hepatectomy.     

Hepatocyte growth factor/scatter factor (HGF/SF) is produced by human bone marrow stromal cells and promotes proliferation, adhesion and survival of human hematopoietic progenitor cells (CD34+)

The fate of hematopoietic progenitor cells (HPCs) in the bone marrow (BM) microenvironment is determined by two different interactions: 1) they adhere (via integrins) to both extracellular matrix molecules and BM stromal cells; and 2) stromal cells produce cytokines that influence their survival, proliferation, differentiation, and mobilization. The ligands for the protein tyrosine kinase receptors c-KIT and FLT3/FLK2, stem cell factor (SCF), and FL are produced by BM stromal cells and are known to affect several facets of hematopoiesis. We studied another protein tyrosine kinase receptor, c-MET, and its ligand hepatocyte growth factor (HGF), also known as scatter factor (SF), which play a similar role in hematopoiesis. c-MET mRNA is expressed in immature human BM HPCs (CD34+CD33- or CD34+CD38-), but not in more mature HPCs (CD34+CD33+ or CD34+CD38+). The ligand HGF/SF is predominantly produced by BM stromal cells at both the mRNA and protein levels. We confirmed functionally that HGF/SF alone has no effect on proliferation of HPCs, but that when combined with granulocyte/macrophage colony-stimulating factor (GM-CSF) or interleukin-3 it acts as a synergistic proliferative factor, although not as potently as kit-ligand or FLT-3/FLK-2 ligand. Furthermore, HGF/SF promotes adhesion of HPCs to immobilized fibronectin. HGF/SF-induced adhesion to fibronectin is probably caused by activation of the integrins alpha4beta1 and alpha5beta1, insofar as we were able to block this interaction by using monoclonal blocking antibodies directed against these integrin subunits. Addition of the tyrosine-phosphorylation inhibitor genistein inhibited HGF/SF-induced adhesion, supporting the idea that HGF/SF-induced effects are the result of signaling via the receptor c-MET after ligand binding. The enhanced adhesion of HGF/SF to fibronectin proved to be beneficial for the maintenance of the colony-forming potential of HPCs. HGF/SF alone and especially in combination with fibronectin prolongs survival of GM colony-forming cells in liquid culture. Our data indicate that HGF/SF is a polyfunctional cytokine in the BM microenvironment. It is produced by human BM stromal cells and directly or indirectly promotes proliferation, adhesion, and survival of human HPCs.     

Insulin-like growth factor-1 acts as a chemoattractant factor for 5T2 multiple myeloma cells

The chemotactic and growth-stimulatory effect of insulin-like growth factor 1 (IGF-1) was investigated in the experimental mouse 5T2 multiple myeloma (MM) model. Chemotaxis was analyzed by classical checkerboard analysis. Bone marrow fibroblasts-conditioned medium exhibited a chemotactic effect on 5T2 MM cells that could be neutralized by adding a blocking antibody to IGF-1. On the other hand, exogenously added IGF-1 also had a chemotactic effect on the 5T2 MM cells. Moreover, in vitro analysis demonstrated that transmigrated 5T2 MM cells have a higher expression of IGF-1 receptor, both in bone marrow-conditioned medium and in IGF-1-induced chemotaxis, in comparison to cells before migration. When analyzed in vivo, 18 hours after injection of the heterogeneous 5T2 MM population, 5T2 MM cells present in the bone marrow show a higher expression of the IGF-1 receptor than their counterparts before injection. When the proliferative effect of IGF-1 was analyzed, no stimulation was observed, which is in contrast to the influence of bone marrow-conditioned medium and interleukin-6. Our results suggest a causal relationship between the presence of IGF-1 in the bone marrow and the chemotaxis of MM cells to and their subsequent presence in the bone marrow.