Fibroblast growth factor-2 induces hepatocyte growth factor/scatter factor expression in osteoblasts

Proteomic identification of serum proteins to induce osteoconductivity of hydroxyapatite

We performed proteomic analysis of rat serum proteins adsorbed on hydroxyapatite (HAp) and α-alumina (α-Al₂O₃) in order to identify proteins that specifically adsorb onto HAp and control cellular responses. Proteins with either or both molecular weight of 22-32 kDa and computed isoelectric point of 5.0-5.5 were preferentially adsorbed on HAp. In total, 182 proteins were adsorbed on both HAp and α-Al₂O₃, of which 14 were highly enriched on HAp, whereas 68 were adsorbed only on HAp. Therefore, 82 (14+68) proteins were further evaluated by bioinformatics and literature-based analyses. We predicted that hepatocyte growth factor and angiopoietin-like protein 3 (ANGPTL3) are candidate proteins responsible for the osteoconductivity of HAp. Although ANGPTL3 promoted the attachment and spreading of MC3T3-E1 cells, it did not promote their proliferation and differentiation. Our results suggest that specific adsorption of ANGPTL3 on HAp induced osteoconductivity by enhancing the attachment and spreading of osteoblasts.

Elevated serum level of hepatocyte growth factor predicts development of new syndesmophytes in men with ankylosing spondylitis

Objectives

To study baseline serum hepatocyte growth factor (s-HGF) as a predictor of spinal radiographic progression overall and by sex and to analyse factors correlated to changes in s-HGF in patients with AS.

Methods

At baseline and the 5-year follow-up, s-HGF was analysed with ELISA. Spinal radiographs were graded according to modified Stoke Ankylosing Spondylitis Spinal Score. Radiographic progression was defined as ≥2 modified Stoke Ankylosing Spondylitis Spinal Score units/5 years or development of ≥1 syndesmophyte. Logistic regression analyses were used.

Results

Of 204 baseline participants, 163 (80%) completed all examinations at the 5-year follow-up (54% men). Baseline s-HGF was significantly higher in men who developed ≥1 syndesmophyte compared with non-progressors, median (interquartile range) baseline s-HGF 1551 (1449–1898) vs 1436 (1200–1569) pg/ml, P = 0.003. The calculated optimal cut-off point for baseline s-HGF ≥1520 pg/ml showed a sensitivity of 70%, a specificity of 69% and univariate odds radio (95% CI) of 5.25 (1.69, 14.10) as predictor of development of ≥1 new syndesmophyte in men. Baseline s-HGF ≥1520 pg/ml remained significantly associated with development of ≥1 new syndesmophyte in men in an analysis adjusted for the baseline variables age, smoking, presence of syndesmophytes and CRP, odds radio 3.97 (1.36, 11.60). In women, no association with HGF and radiographic progression was found. Changes in s-HGF were positively correlated with changes in ESR and CRP.

Conclusion

In this prospective cohort study elevated s-HGF was shown to be associated with development of new syndesmophytes in men with AS.

Hepatocyte growth factor is a potential biomarker for osteoproliferation and osteoporosis in ankylosing spondylitis

We explored relations between serum hepatocyte growth factor (HGF), disease activity, osteoproliferation, and bone mineral density (BMD) in ankylosing spondylitis (AS), in comparison with healthy controls. HGF was increased especially in male AS patients and smokers and associated with both lower BMD and more chronic radiographic changes in the spine.

INTRODUCTION

Ankylosing spondylitis (AS) is characterized by both osteoproliferation and increased bone loss. Biomarkers are requested to predict the processes. The aims of this study were to compare serum levels of hepatocyte growth factor (HGF), matrix metalloproteinase-3 (MMP-3), and vascular endothelial growth factor (VEGF) in AS patients with healthy controls (HC) and to explore the associations with disease activity, osteoproliferation, and bone mineral density (BMD).

METHODS

Serum from AS patients (modified NY-criteria) and HC was analyzed for HGF, MMP-3, and VEGF with ELISA. Disease activity parameters were collected. Osteoproliferation was assessed with modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) and BMD was measured in femoral neck.

RESULTS

Totally, 204 AS patients and 80 sex and age matched HC were included. Serum HGF was higher in the AS patients compared with the HC, whereas serum MMP-3 and VEGF were not. Serum HGF was also higher in smokers and in the male AS patients positively correlated with age, BASMI, and mSASSS, and negatively correlated with BMD. The biomarkers were all positively associated with ESR, CRP, and WBC. In multiple linear regression analysis serum HGF remained associated with higher mSASSS and lower BMD, after adjusting for age, sex, CRP, smoking, and body mass index.

CONCLUSIONS

Serum HGF was increased in male AS patients and associated with higher mSASSS and lower BMD. In addition, serum HGF was positively associated with risk factors for osteoproliferation such as age, CRP and smoking. HGF could be a potential biomarker of importance for the bone metabolism in AS.

TRIAL REGISTRATION

NCT00858819.

Fibroblast growth factor-2 drives and maintains progressive corneal neovascularization following HSV-1 infection

Herpes simplex virus type 1 (HSV-1) infection of the cornea induces vascular endothelial growth factor A (VEGF-A)-dependent lymphangiogenesis that continues to develop well beyond the resolution of infection. Inflammatory leukocytes infiltrate the cornea and have been implicated to be essential for corneal neovascularization, an important clinically relevant manifestation of stromal keratitis. Here we report that cornea infiltrating leukocytes including neutrophils and T cells do not have a significant role in corneal neovascularization past virus clearance. Antibody-mediated depletion of these cells did not impact lymphatic or blood vessel genesis. Multiple pro-angiogenic factors including IL-6, angiopoietin-2, hepatocyte growth factor, fibroblast growth factor-2 (FGF-2), VEGF-A, and matrix metalloproteinase-9 were expressed within the cornea following virus clearance. A single bolus of dexamethasone at day 10 post infection (pi) resulted in suppression of blood vessel genesis and regression of lymphatic vessels at day 21 pi compared to control-treated mice. Whereas IL-6 neutralization had a modest impact on hemangiogenesis (days 14-21 pi) and lymphangiogenesis (day 21 pi) in a time-dependent fashion, neutralization of FGF-2 had a more pronounced effect on the suppression of neovascularization (blood and lymphatic vessels) in a time-dependent, leukocyte-independent manner. Furthermore, FGF-2 neutralization suppressed the expression of all pro-angiogenic factors measured and preserved visual acuity.

Phosphoproteome Profiling Reveals Molecular Mechanisms of Growth-Factor-Mediated Kinase Inhibitor Resistance in EGFR-Overexpressing Cancer Cells

Although substantial progress has been made regarding the use of molecularly targeted cancer therapies, resistance almost invariably develops and presents a major clinical challenge. The tumor microenvironment can rescue cancer cells from kinase inhibitors by growth-factor-mediated induction of pro-survival pathways. Here we show that epidermal growth factor receptor (EGFR) inhibition by Gefitinib is counteracted by growth factors, notably FGF2, and we assessed the global molecular consequences of this resistance at the proteome and phosphoproteome level in A431 cells. Tandem mass tag peptide labeling and quantitative mass spectrometry allowed the identification and quantification of 22 000 phosphopeptides and 8800 proteins in biological triplicates without missing values. The data show that FGF2 protects the cells from the antiproliferative effect of Gefitinib and largely prevents reprogramming of the proteome and phosphoproteome. Simultaneous EGFR/FGFR or EGFR/GSG2 (Haspin) inhibition overcomes this resistance, and the phosphoproteomic experiments further prioritized the RAS/MEK/ERK as well as the PI3K/mTOR axis for combination treatment. Consequently, the MEK inhibitor Trametinib prevented FGF2-mediated survival of EGFR inhibitor-resistant cells when used in combination with Gefitinib. Surprisingly, the PI3K/mTOR inhibitor Omipalisib reversed resistance mediated by all four growth factors tested, making it an interesting candidate for mitigating the effects of the tumor microenvironment.

Conditional genetic elimination of hepatocyte growth factor in mice compromises liver regeneration after partial hepatectomy

Hepatocyte growth factor (HGF) has been shown to be indispensable for liver regeneration because it serves as a main mitogenic stimulus driving hepatocytes toward proliferation. We hypothesized that ablating HGF in adult mice would have a negative effect on the ability of hepatocytes to regenerate. Deletion of the HGF gene was achieved by inducing systemic recombination in mice lacking exon 5 of HGF and carrying the Mx1-cre or Cre-ER(T) transgene. Analysis of liver genomic DNA from animals 10 days after treatment showed that a majority (70-80%) of alleles underwent cre-induced genetic recombination. Intriguingly, however, analysis by RT-PCR showed the continued presence of both unrecombined and recombined forms of HGF mRNA after treatment. Separation of liver cell populations into hepatocytes and non-parenchymal cells showed equal recombination of genomic HGF in both cell types. The presence of the unrecombined form of HGF mRNA persisted in the liver in significant amounts even after partial hepatectomy (PH), which correlated with insignificant changes in HGF protein and hepatocyte proliferation. The amount of HGF produced by stellate cells in culture was indirectly proportional to the concentration of HGF, suggesting that a decrease in HGF may induce de novo synthesis of HGF from cells with residual unrecombined alleles. Carbon tetrachloride (CCl4)-induced regeneration resulted in a substantial decrease in preexisting HGF mRNA and protein, and subsequent PH led to a delayed regenerative response. Thus, HGF mRNA persists in the liver even after genetic recombination affecting most cells; however, PH subsequent to CCl4 treatment is associated with a decrease in both HGF mRNA and protein and results in compromised liver regeneration, validating an important role of this mitogen in hepatic growth.

Hepatocyte growth factor (HGF) and 1,25-dihydroxyvitamin D together stimulate human bone marrow-derived stem cells toward the osteogenic phenotype by HGF-induced up-regulation of VDR

Bone formation and remodeling require generation of osteoprogenitors from bone marrow stem cells (MSC), which are regulated by growth factors and hormones, with putative roles in mesenchymal cell differentiation. Hepatocyte growth factor (HGF) is a pleiotropic growth factor, and together with its high affinity receptor cMet are widely expressed in normal tissues. 1,25-dihydroxyvitamin D (1,25OHD) is the most active metabolite of vitamin D; produced mainly in the kidney, but also by osteoblasts. We previously reported that HGF and 1,25OHD act together to increase osteogenic differentiation of human MSC (hMSC) potentially through increasing p53. Although p53 does not induce the vitamin D receptor (VDR), p63, a member of the p53 family of transcription factors has been reported to up-regulate VDR expression in some tumor cell lines, and thus might play a part in HGF-regulated VDR expression. Our hypothesis is that the combination of HGF and 1,25OHD can induce hMSC differentiation by up-regulation of 1,25OHD and/or VDR expression to increase cell response(s) to 1,25OHD. Using real-time RT-qPCR, Western blots, luciferase reporter assays, and siRNAs, as well as antibodies to specific signaling molecules we showed that HGF induced VDR gene expression, as well as up-regulated p63 gene expression. p63 gene knockdown by siRNA eliminated the effects of HGF on VDR gene expression as measured by RT-qPCR, Western blots and luciferase reporter assay, and downstream on osteogenic differentiation markers, including alkaline phosphatase staining. Differentiation is a coordinated process of cell cycle exit and tissue-specific gene expression. These results suggest HGF might be a good candidate to coordinate the regulation of these two processes during hMSC osteogenic differentiation. p63 could be a key connecting molecule on the pathway of HGF-induced VDR expression. Understanding the role of these factors and their actions could have important clinical implications for the use of hMSC in the development of novel stem cell therapies.

Human bone marrow-derived stem cell proliferation is inhibited by hepatocyte growth factor via increasing the cell cycle inhibitors p53, p21 and p27

Human bone marrow-derived stem cells (hMSCs) are a major source of osteoprogenitors. Hepatocyte growth factor (HGF), a glycoprotein constitutively produced by hMSCs, is reported to act on differentiated osteoblasts and also osteoclasts. Moreover, HGF has been shown by us and others to enhance osteoblastic differentiation from hMSCs. Typically, the pro-differentiation effects of HGF have required cooperative action with regulatory factors such as vitamin D or bone matrix material. Here, we have pursued the molecular mechanisms underlying the osteogenic effect of HGF on hMSCs, the principal precursors to bone forming cells. HGF treatment of hMSCs reduced the cell number over time and increased G1/S cell-cycle arrest compared to control (non-treated) cells. RT-qPCR showed treatment with HGF increased gene expression of the cell-cycle inhibitors p53, p21, and p27, possibly explaining the cell growth inhibition and G1 arrest, a step critical to phenotypic differentiation. Transfection of siRNA specific for cMet, the HGF receptor, eliminated the HGF anti-proliferation effect on hMSCs and the HGF-mediated increase in p53, p21, and p27, strongly supporting a role for these cell-cycle inhibitors in HGF's regulation of hMSCs. HGF in combination with a known inducer of osteogenic differentiation, 1,25-dihydroxyvitamin D, significantly increased cell maturation/differentiation as indicated by an increase in several osteoblast markers. Taken together these results demonstrate that HGF significantly enhances hMSC osteoblast differentiation by 1,25-dihydroxyvitamin D.

Hepatocyte growth factor--a new marker for prognosis in acute coronary syndrome

This study was designed to check the properties of hepatocyte growth factor (HGF) as a new marker of myocardial necrosis.

MATERIALS AND METHOD

In one hundred and four patients with acute coronary syndrome (ACS), plasma human HGF (hHGF) concentrations were assessed twice, i.e. just after admission to hospital and 24 h afterwards. The primary composite endpoint was assessed at three-month follow-up.

RESULTS

The maximal concentration of hHGF (1902 pg/ml) was reached at the time of admission to hospital due to ACS with significant decrease 24 h after the first measurement (705 pg/ml p < 0.0001). hHGF levels in ST segment elevation myocardial infarction (STEMI) were higher than in non-ST segment elevation myocardial infarction (NSTEMI) and in patients who reached composite primary endpoint (33 patients-4211 pg/ml) vs. event-free 71 patients (1013 pg/ml p < 0.01). The correlation between values of hHGF and N-terminal prohormone B-type natriuretic peptide and cardiac troponin I was revealed.

CONCLUSION

HGF is a very early, good marker of myocardial necrosis and a sensitive short- and long-term prognostic factor in ACS.

IFATS collection: Fibroblast growth factor-2-induced hepatocyte growth factor secretion by adipose-derived stromal cells inhibits postinjury fibrogenesis through a c-Jun N-terminal kinase-dependent mechanism

Adipose-derived stem/stromal cells (ASCs) not only function as tissue-specific progenitor cells but also are multipotent and secrete angiogenic growth factors, such as hepatocyte growth factor (HGF), under certain circumstances. However, the biological role and regulatory mechanism of this secretion have not been well studied. We focused on the role of ASCs in the process of adipose tissue injury and repair and found that among injury-associated growth factors, fibroblast growth factor-2 (FGF-2) strongly promoted ASC proliferation and HGF secretion through a c-Jun N-terminal kinase (JNK) signaling pathway. In a mouse model of ischemia-reperfusion injury of adipose tissue, regenerative changes following necrotic and apoptotic changes were seen for 2 weeks. Acute release of FGF-2 by injured adipose tissue was followed by upregulation of HGF. During the adipose tissue remodeling process, adipose-derived 5-bromo-2-deoxyuridine-positive cells were shown to be ASCs (CD31-CD34+). Inhibition of JNK signaling inhibited the activation of ASCs and delayed the remodeling process. In addition, inhibition of FGF-2 or JNK signaling prevented postinjury upregulation of HGF and led to increased fibrogenesis in the injured adipose tissue. Increased fibrogenesis also followed the administration of a neutralizing antibody against HGF. FGF-2 released from injured tissue acts through a JNK signaling pathway to stimulate ASCs to proliferate and secrete HGF, contributing to the regeneration of adipose tissue and suppression of fibrogenesis after injury. This study revealed a functional role for ASCs in the response to injury and provides new insight into the therapeutic potential of ASCs.

Percutaneous nonviral delivery of hepatocyte growth factor in an osteotomy gap promotes bone repair in rabbits: a preliminary study

Hepatocyte growth factor (HGF) was initially identified in cultured hepatocytes and subsequently reported to induce angiogenic, morphogenic, and antiapoptotic activity in various tissues. These properties suggest a potential influence of HGF on bone healing. We asked if gene transfer of human HGF (hHGF) into an osteotomy gap with a hemagglutinating virus of Japan-envelope (HVJ-E) vector promotes bone healing in rabbits. HVJ-E that contained either hHGF or control plasmid was percutaneously injected into the osteotomy gap of rabbit tibias on Day 14. The osteotomy gap was evaluated by radiography, pQCT, mechanical tests, and histology at Week 8. The expression of hHGF was evaluated by reverse transcriptase-polymerase chain reaction and immunohistochemistry at Week 3. Radiography, pQCT, and histology suggested the hHGF group had faster fracture healing. Mechanical tests demonstrated the hHGF group had greater mechanical strength. The injected tissues at 3 weeks expressed hHGF mRNA by reverse transcriptase-polymerase chain reaction. hHGF-positive immunohistochemical staining was observed in various cells at the osteotomy gap at Week 3. The data suggest delivery of hHGF plasmid into the osteotomy gap promotes fracture repair, and HGF could become a novel agent for fracture treatment.

Involvement of MET/TWIST/APC combination or the potential role of ossification factors in pediatric high-grade osteosarcoma oncogenesis

Dysregulated cell growth or differentiation due to misexpression of developmental critical factors seems to be a decisive event in oncogenesis. As osteosarcomas are histologically defined by malignant osteoblasts producing an osteoid component, we prospected in pediatric osteosarcomas treated with OS94 protocol the genomic status of several genes implied in ossification processes. In 91 osteosarcoma cases, we focused on the analysis of the fibroblast growth factor receptors (FGFRs) TWIST, APC, and MET by allelotyping, real-time quantitative polymerase chain reaction, gene sequencing, and protein polymorphism study. Our study supports the frequent role of TWIST, APC, and MET as osteosarcoma markers (50%, 62%, and 50%, respectively). TWIST and MET were mainly found to be deleted, and no additional APC mutation was identified. Surprisingly, FGFRs are abnormal in only < 30%. Most of these factors and their abnormalities seem to be linked more or less to one clinical subgroup, but the most significant correlation is the link of MET, TWIST, and APC abnormalities to a worse outcome and their combination within abnormal tumors. A wider cohort is mandatory to define more robust molecular conclusions, but these results are to be considered as the beginning of a more accurate basis for diagnosis, in search of targeted therapies, and to further characterize prognostic markers.

Combined administration of naked DNA vectors encoding VEGF and bFGF enhances tissue perfusion and arteriogenesis in ischemic hindlimb

Few studies have examined in detail the combined effects of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) gene delivery on collateral development. Here, we evaluated the potential synergism of naked DNA vectors encoding VEGF and bFGF using a skeletal-muscle based ex vivo angiogenesis assay and compared tissue perfusion and limb loss in a murine model of hindlimb ischemia. In the ex vivo angiogenesis assay, the VEGF+bFGF combination group had a larger capillary sprouting area than those of the LacZ, VEGF, and bFGF groups. Consistent with these results, regional blood flow recovery on day 14 was also highest in the VEGF+bFGF combination group, followed by the bFGF, VEGF, and LacZ groups. The limb loss frequency was 0% in the combination group, whereas the limb loss frequencies of the other groups were 7-29%. The ischemic muscles of the combination group revealed evidence of increased angiogenesis and arteriogenesis and the upregulated expression of genes that may be associated with arteriogenesis, such as those for cardiac ankyrin repeat protein, early growth response factor-1, and transforming growth factor-beta1. Our study has implications for the development of a combined gene therapy for the vascular occlusive diseases.

Hepatocyte growth factor (HGF) adsorption kinetics and enhancement of osteoblast differentiation on hydroxyapatite surfaces

Hepatocyte growth factor (HGF) is a growth factor that promotes angiogenesis (tissue vascularization), cell motility, and cell differentiation, making it a potentially beneficial coating for bone implants. However, very little is known about maximizing HGF attachment to surfaces of tissue-engineered scaffolds. Here, we examine methods and kinetics of HGF adsorption onto a dense hydroxyapatite (HA) surface (used in bone implants) and determine the influence of HGF coating on osteoblast phenotype/differentiation. We demonstrate that incubating HA with HGF in solution (and not allowing the solution to dry) resulted in maximal surface adsorption that was not enhanced by extending incubation time beyond 2 days. Daily shaking of the coated HA surface did not remove adsorbed HGF. To further examine the effect of HA on osteoblast phenotype, MC3T3-E1 preosteoblasts were seeded onto HA or HGF-HA surfaces. Gene expression analyses indicate that HGF coating enhanced osteoblast differentiation as demonstrated by increased runx2 (a transcription factor important for osteoblast lineage and differentiation), alkaline phosphatase (marker of mid stage differentiation) and osteocalcin (marker of late stage differentiation) mRNA levels. Taken together, our results demonstrate that HGF can serve as an excellent bone implant coating based on its ability to readily adsorb to HA surfaces, maintain integrity over time, and enhance osteoblast differentiation.

c-Met tyrosine kinase receptor expression and function in human and canine osteosarcoma cells

To further characterize the role of hepatocyte growth factor-scatter factor (HGF-SF) and its receptor (c-Met) in osteosarcoma (OS), human OS cell lines with low (SAOS-2) and high (SAOS-LM2) metastatic potential, and cell lines derived from spontaneous canine OS were studied. All cell lines were evaluated for c-Met and HGF-SF expression and receptor activation using Northern, RT-PCR, and Western blot analyses, respectively. Functional activity of receptor-ligand interaction was measured using c-Met phosphorylation status, proliferation assays (anchorage-dependent and -independent), Matrigel invasion, modulation of urokinase plasminogen activator (uPA) expression, and cell dispersion (scattering). All cell lines exhibited steady-state mRNA expression of c-Met. The canine OS cell lines also expressed HGF-SF mRNA as determined by RT-PCR analysis. Western analysis showed c-Met protein expression and HGF-stimulated (human) or constitutive (canine) receptor autophosphorylation. Treatment with recombinant human HGF resulted in enhanced proliferation in 3 of 5 OS cell lines and enhanced colony formation in 2 of 5 OS cell lines. Matrigel invasion was significantly enhanced in 3 of the cell lines and uPA levels were significantly increased in the SAOS-2 cells following HGF treatment. Scattering was enhanced in both the SAOS-2 and SAOS-LM2 cells. These data support the involvement of c-Met and HGF-SF in the growth and progression of human and canine OS, and may offer new targets for the development of therapeutic strategies for OS.

Hepatocyte growth factor: from diagnosis to clinical applications

Hepatocyte growth factor (HGF), initially identified and molecularly cloned as a potent mitogen of primary cultured hepatocytes, has multiple activities in a variety of tissues during the course of development and also in various disease states. HGF plays key roles in the attenuation of disease progression as an intrinsic repair factor. It is also evident that HGF levels are regulated under different conditions, for example, during the course of pregnancy, aging, and disease. This review focuses on the levels of HGF in normal and pathophysiological situations and examines the relationships between HGF levels and disease, disease stage, and disease prognosis. The clinical potential of HGF as a treatment for subjects with various diseases is also given attention.

1alpha,25(OH)2-vitamin D3 inhibits HGF synthesis and secretion from MG-63 human osteosarcoma cells

Several mesenchymally derived cells, including osteoblasts, secrete hepatocyte growth factor (HGF). 1alpha,25(OH)(2)-vitamin D(3) [1,25(OH)(2)D(3)] inhibits proliferation and induces differentiation of MG-63 osteoblastic cells. Here we show that MG-63 cells secrete copious amounts of HGF and that 1,25(OH)(2)D(3) inhibits HGF production. MG-63 cells also express HGF receptor (c-Met) mRNA, suggesting an autocrine action of HGF. Indeed, although exogenous HGF failed to stimulate cellular proliferation, neutralizing endogenous HGF with a neutralizing antibody inhibited MG-63 cell proliferation; moreover, inhibiting HGF synthesis with 1,25(OH)(2)D(3) followed by addition of HGF rescued hormone-induced inhibition of proliferation. Nonneutralized cells displayed constitutive phosphorylation of c-Met and the mitogen-activated protein kinases mitogen/extracellular signal-regulated kinase (MEK) 1 and extracellular signal-regulated kinase (Erk) 1/2, which were inhibited by anti-HGF antibody. Constitutive phosphorylation of Erk1/2 was also abolished by 1,25(OH)(2)D(3). Addition of HGF to MG-63 cells treated with neutralizing HGF antibody induced rapid phosphorylation of c-Met, MEK1, and Erk1/2. Thus endogenous HGF induces a constitutively active, autocrine mitogenic loop in MG-63 cells. The known antiproliferative effect of 1,25(OH)(2)D(3) on MG-63 cells can be accounted for by the concomitant 1,25(OH)(2)D(3)-induced inhibition of HGF production.

Fibroblast growth factor-2 gene transfer can stimulate hepatocyte growth factor expression irrespective of hypoxia-mediated downregulation in ischemic limbs

Hepatocyte growth factor (HGF) is a potent angiogenic polypeptide that stimulates angiogenesis. Transcriptional regulation of HGF, however, has not been fully defined, with the exception of the hypoxia-mediated downregulation in cultured cells. In the present study, we report that angiogenic growth factors, including HGF, were upregulated in a murine model of critical limb ischemia in vivo, a finding that was in conflict with previous in vitro data. Mice deficient in basic fibroblast growth factor-2 (FGF-2) showed reduced induction of HGF protein in ischemic muscles, and overexpression of FGF-2 via gene transfer stimulated endogenous HGF, irrespective of the presence of ischemia. In culture, FGF-2 rapidly stimulated HGF mRNA, and a sustained expression was evident in the time course in vascular smooth muscle cells and fibroblasts. FGF-2-mediated induction of HGF was fully dependent on the mitogen-activated protein kinase pathway yet was not affected by either hypoxia or a protein kinase A inhibitor. In the early expression, FGF-2 directly stimulated HGF mRNA without the requirement of new protein synthesis, whereas sustained induction of HGF in the later phase was partly mediated by platelet-derived growth factor-AA. Furthermore, in vivo overexpression of FGF-2 significantly improved the blood perfusion, and the effect was abolished by systemic blockade of HGF in ischemic limbs. This is the first demonstration of a regulational mechanism of HGF expression via FGF-2 that was independent of the presence of hypoxia. The harmonized therapeutic effects of FGF-2, accompanied with the activity of endogenous HGF, may provide a beneficial effect for the treatment of limb ischemia.

SF/HGF-c-Met autocrine and paracrine promote metastasis of hepatocellular carcinoma

AIM: To explore the role of SF/HGF-Met autocrine and paracrine in met astasis of hepatocellular carcinoma (HCC).

METHODS: SF/HGF and c-met transcri ption and protein expression in HCC were examined by RT-PCR and Western Blot in 4 HCC cell lines, including HepG2, Hep3B, SMMC7721 and MHCC-1, the last cell line had a higher potential of metastasis. sf/hgf cDNA was transfected by the method of Lipofectin into SMMC7721. SF/HGF and c-met antibody were used to stimulate and block SF/HGF-c-met signal transduction. Cell morphology, mobility, and proliferation were respectively compared by microscopic observation, wound healing assay and cell growth curve.

RESULTS: HCC malignancy appeared to be relative to its met-SF/HGF expression. In MHCC-1, c-met expression was much stronger than that in other cell lines with lower potential of metastasis and only SF/HG F autocrine existed in MHCC-1. After sf/hgf cDNA transfection or conditioned medium of MHCC-1 stimulation, SMMC7721 changed into elongated morphology, and the abilities of proliferation (P < 0.05) and mobility increased. Such bio-activity could be blocked by c-met antibody (P < 0.05).

CONCLUSION: The system of SF/HGF-c- met autocrine and paracrine played an important role in development and metastas is potential of HCC. Inhibition of SF/HGF-c-met signal transduction system may reduce the growth and metastasis of HCC.

The hepatocyte growth factor/Met pathway in development, tumorigenesis, and B-cell differentiation

This article summarizes the structure, signal transduction and physiologic functions of the HGF/Met pathway, as well as its role in tumor growth, invasion, and metastasis. Moreover, it highlights recent studies indicating a role for the HGF/Met pathway in antigen-specific B-cell development and B-cell neoplasia.

Cortisol inhibits hepatocyte growth factor/scatter factor expression and induces c-met transcripts in osteoblasts

Hepatocyte growth factor/scatter factor (HGF/SF) is expressed by osteoblasts and has important effects on repair and bone remodeling. Because glucocorticoids regulate these two functions, we tested the effects of cortisol on the expression of HGF/SF and c-met, the protooncogene encoding the HGF/SF receptor, in cultures of osteoblast-enriched cells from 22-day fetal rat calvariae (Ob cells). Cortisol decreased HGF/SF mRNA levels and diminished the induction of HGF/SF transcripts by fibroblast growth factor-2 (FGF-2) and platelet-derived growth factor BB (PDGF BB). Cortisol also decreased FGF-2 and PDGF BB-induced HGF/SF mRNA and polypeptide levels in MC3T3 cells. In contrast, cortisol enhanced the expression of c-met transcripts in Ob cells. Cortisol did not modify the half-life of HGF/SF or of c-met mRNA in transcriptionally arrested cells, and it increased the rate of transcription of c-met. In conclusion, cortisol decreases HGF/SF transcripts in Ob cells and enhances c-met expression transcriptionally. The effects of cortisol on HGF/SF could be relevant to its inhibitory actions on bone formation and repair.