c-Met mRNA Expression Research Articles

Pulmonary expression of the hepatocyte growth factor receptor c-Met shifts from medial to intimal layer after cavopulmonary anastomosis

Objective Pulmonary arteriovenous malformations occur in up to 60% of patients after cavopulmonary anastomosis. We compared the effects of cavopulmonary anastomosis and pulmonary artery banding on lung gene expression in an ovine model to study the abnormal pulmonary vascular remodeling after the exclusion of inferior vena caval blood independent of reduced pulmonary blood flow. We previously demonstrated by contrast echocardiography that pulmonary arteriovenous malformations develop by 8 weeks after cavopulmonary anastomosis but not after pulmonary artery banding. Hepatocyte growth factor, a pleiotropic factor with morphogenic, mitogenic, and angiogenic activities, signals via its specific receptor c-Met to induce the antiapoptotic factor Bcl-2. In this study, we examined pulmonary artery expression of these factors and their potential role in pulmonary artery remodeling after cavopulmonary anastomosis and pulmonary artery banding. Methods Eighteen lambs aged 35 to 45 days were placed into 3 groups: cavopulmonary anastomosis, pulmonary artery banding, and control (n = 6/group). In the cavopulmonary anastomosis group, the superior vena cava was anastomosed to the right pulmonary artery in an end-to-end fashion. In the pulmonary artery banding group, the left pulmonary artery was banded to reduce blood flow to 20% of control. The control group had a simple right pulmonary artery clamp for 30 minutes. Lung was harvested for Western blot, reverse transcriptase–polymerase chain reaction, and immunostaining at 2 weeks (n = 3/group) and 5 weeks (n = 3/group) after surgery. Results The expression of c-Met mRNA after cavopulmonary anastomosis was increased by twofold compared with the control or pulmonary artery banding group. The total lung expression of c-Met by Western blot was also up regulated at 2 weeks ( P < .05). However, total lung expression of hepatocyte growth factor and Bcl-2 by Western and reverse transcriptase–polymerase chain reaction was not different from the control and pulmonary artery banding groups at both 2 and 5 weeks after surgery. Immunohistochemical analysis revealed that c-Met expression was localized to the intimal layer of the pulmonary artery in the cavopulmonary anastomosis, while its expression in the control and pulmonary artery banding lungs was localized to the medial layer. Localization of Bcl-2 on the intimal layer in lambs with cavopulmonary anastomosis followed the same pattern as c-Met. Conclusions After cavopulmonary anastomosis, pulmonary artery expression of the hepatocyte growth factor receptor c-Met and one of its downstream effectors, Bcl-2, had increased in the intimal layer and decreased in the medial layer. Because the hepatocyte growth factor signaling promotes increased endothelial cell survival, it may have a role in pulmonary artery remodeling following cavopulmonary anastomosis. In addition, the change of c-Met expression in the medial layer after cavopulmonary anastomosis suggests a possible mechanism for the smooth muscle cell alteration related to abnormal angiogenesis.

Suppression of HGF receptor gene expression by oxidative stress is mediated through the interplay between Sp1 and Egr-1

Hepatocyte growth factor (HGF) receptor, the product of the c-met protooncogene, is transcriptionally regulated by a wide variety of cytokines as well as extracellular environmental cues. In this report, we demonstrate that c-met expression was significantly suppressed by oxidative stress. Treatment of mouse renal inner medullary collecting duct epithelial cells with 0.5 mM H(2)O(2) inhibited c-met mRNA and protein expression, which was concomitant with induction of Egr-1 transcription factor. Ectopic expression of Egr-1 in renal epithelial cells markedly inhibited endogenous c-met expression in a dose-dependent fashion, suggesting a causative effect of Egr-1 in mediating c-met suppression. The cis-acting element responsible for H(2)O(2)-induced c-met inhibition was localized at nucleotide position -223 to -68 of c-met promoter, in which reside an imperfect Egr-1 and three Sp1-binding sites. Egr-1 markedly suppressed c-met promoter activity but did not directly bind to its cis-acting element in the c-met gene. Induction of Egr-1 by oxidative stress attenuated the binding of Sp1 to its cognate sites, but it did not affect Sp1 abundance in renal epithelial cells. Immunoprecipitation uncovered that Egr-1 physically interacted with Sp1 by forming the Sp1/Egr-1 complex, which presumably resulted in a decreased availability of unbound Sp1 as a transcriptional activator for the c-met gene. Thus it appears that inhibition of c-met expression by oxidative stress is mediated by the interplay between Sp1 and Egr-1 transcription factors. Our findings reveal a novel transcriptional regulatory mechanism by which Egr-1 sequesters Sp1 as a transcriptional activator of c-met via physical interaction.

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.

Establishment of a new human synovial sarcoma cell line, FU-SY-1, that expresses c-Met receptor and its ligand hepatocyte growth factor

Only a small number of human synovial sarcoma cell lines have been reported, and of those, not all have been fully characterized, especially at the molecular level. We describe here the establishment and characterization of a new human cell line, FU-SY-1, which originated from a monophasic fibrous synovial sarcoma arising in the supinator muscle of a 31-year-old woman. This cell line propagated continuously in vitro for 73 serial passages for more than 36 months. FU-SY-1 cells in vitro were rather small, exhibited a spindle or polygonal shape without conspicuous pleomorphism, and expressed c-Met and hepatocyte growth factor (HGF) as determined by immunocytochemistry. Cytogenetically, FU-SY-1 cells maintained a consistent karyotype: 47, X, +7, t(X;18)(p11.2;q11.2), the same as that of the original tumor specimen. Reverse transcriptase-polymerase chain reaction (RT-PCR) demonstrated a SYT-SSX fusion transcript and expression of c-Met and HGF mRNA in FU-SY-1 cells. A subsequent sequence analysis using the PCR products confirmed that the detected messages were derived from the SYT-SSX1 fusion gene. This cell line, FU-SY-1, established from a monophasic fibrous synovial sarcoma, may therefore be a useful tool for investigation of the mechanisms of tumorigenesis and progression in human synovial sarcomas.

Detection of cancer cells in peripheral blood of stomach cancer patients using RT-PCR amplification of tumour-specific mRNAs.

RT-PCR amplification of tumour-specific mRNA has been used for the detection of cancer cells in peripheral blood. To evaluate the characteristics of the tumour specific mRNA species in peripheral blood of stomach cancer patients. We analysed CEA, GalNAc-T, MUC-1, c-MET and hTERT mRNA expression in the stomach cancer cell lines and tissues, lymph nodes and peripheral blood of stomach cancer patients using RT-PCR. In RT-PCR analysis of the peripheral blood, 4%, 8%, 21%, 46%, and 100% of stomach cancer patients were positive for CEA, GalNAc-T, c-MET, hTERT and MUC-1 mRNA, respectively, but MUC-1 mRNA was also positive in all normal blood samples. The detection of hTERT mRNA was correlated with poor differentiation (P = 0.01) and lymph node metastasis (P = 0.009). The presence of c-MET mRNA was correlated with T stage (P = 0.025), lymph node metastasis (P = 0.036), distant metastasis (P = 0.031), and stage of the stomach cancer (P = 0.023). Our study suggest that hTERT mRNA in peripheral blood can be a molecular marker for gastric cancer. We also showed that each molecular marker can be correlated with the clinicopathological features of the patients.

Overexpression of c-met as a Prognostic Indicator for Transitional Cell Carcinoma of the Urinary Bladder: A Comparison With p53 Nuclear Accumulation

PURPOSE: The c-met proto-oncogene encodes a receptor tyrosine kinase (Met) and has been shown to play a role in oncogenesis. Given that high titers of hepatocyte growth factor, the specific ligand for Met, are excreted in the urine and tend to reflect disease activity of bladder cancer, we performed this study to examine the clinical significance of Met in human bladder cancer. MATERIALS AND METHODS: We studied the mRNA expression and genomic alteration of c-met in five bladder cancer cell lines. Significance of Met overexpression was then compared with p53 nuclear accumulation (TP53) in primary bladder cancer (n = 142 patients). RESULTS: Expression of c-met mRNA tended to positively correlate with differentiation of cancer cell lines in the absence of point mutation. High expression of Met was found in seven cases (4.9%), low expression in 32 cases (22.5%), and negative expression in 103 cases (72.5%). Expression of Met was positively associated with histologic grade, stage classification, tumor size, an...

Selective Cyclooxygenase-2 Blocker Delays Healing of Esophageal Ulcers in Rats and Inhibits Ulceration-Triggered c-Met/Hepatocyte Growth Factor Receptor Induction and Extracellular Signal-Regulated Kinase 2 Activation

Nonsteroidal anti-inflammatory drugs, both nonselective and cyclooxygenase-2 (COX-2) selective, delay gastric ulcer healing. Whether they affect esophageal ulcer healing remains unexplored. We studied the effects of the COX-2 selective inhibitor, celecoxib, on esophageal ulcer healing as well as on the cellular and molecular events involved in the healing process. Esophageal ulcers were induced in rats by focal application of acetic acid. Rats with esophageal ulcers were treated intragastrically with either celecoxib (10 mg/kg, once daily) or vehicle for 2 or 4 days. Esophageal ulceration triggered increases in: esophageal epithelial cell proliferation; expression of COX-2 (but not COX-1); hepatocyte growth factor (HGF) and its receptor, c-Met; and activation of extracellular signal-regulated kinase 2 (ERK2). Treatment with celecoxib significantly delayed esophageal ulcer healing and suppressed ulceration-triggered increases in esophageal epithelial cell proliferation, c-Met mRNA and protein expression, and ERK2 activity. In an ex vivo organ-culture system, exogenous HGF significantly increased ERK2 phosphorylation levels in esophageal mucosa. A structural analog of celecoxib, SC-236, completely prevented this effect. These findings indicate that celecoxib delays esophageal ulcer healing by reducing ulceration-induced esophageal epithelial cell proliferation. These actions are associated with, and likely mediated by, down-regulation of the HGF/c-Met-ERK2 signaling pathway.

Expression and action of hepatocyte growth factor in bovine endometrial stromal and epithelial cells in vitro.

Hepatocyte growth factor (HGF) is a pleiotropic growth factor that acts on various epithelial cells. The objectives of this study were to determine whether HGF altered the proliferation and prostaglandin (PG) secretion of bovine endometrial stromal and epithelial cells in vitro. We also observed HGF and HGF receptor (c-met) mRNA expression in cultured bovine endometrial stromal and epithelial cells by RT-PCR. Stromal and epithelial cells obtained from cows in early stage of the estrous cycle (days 2-5) were cultured in DMEM/Ham's F-12 supplemented with 10% calf serum. The cells were exposed to HGF (0-10 ng/ml) for 2, 4, or 6 days. HGF significantly increased the total DNA in epithelial (P < 0.05), but not stromal cells. In another experiment, when the cells reached confluence, the culture medium was replaced with fresh medium with 0.1% BSA containing HGF 0-100 ng/ml and the cells were cultured for 24 hr. The HGF stimulated PGF2alpha secretion in epithelial, but not stromal cells. RT-PCR revealed that mRNA of HGF is expressed only in stromal cells, and that c-met mRNA is expressed in both stromal and epithelial cells. These results suggest that HGF plays roles in the proliferation and the regulation of secretory function of bovine endometrial epithelial cells in a paracrine fashion.

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

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

Absence of tpr-met and expression of c-met in human gastric mucosa and carcinoma.

The c-met proto-oncogene, encoding the hepatocyte growth factor receptor, can be activated by various mechanisms. These include, among others, gene amplification with concomitant overexpression and the tpr-met oncogenic rearrangement. In the case of gastric cancer, contradictory results on the presence of the tpr-met oncogenic rearrangement have been published. The current study aimed therefore to assess the prevalence of tpr-met expression in Caucasian gastric adenocarcinomas, to evaluate the importance of this oncogene in their carcinogenesis. In addition, the level of c-met expression was determined, to evaluate the role of this alternative mode of activation of the proto-oncogene. A series of Caucasian gastric adenocarcinomas (n=43) and normal gastric mucosal samples (n=14) was analysed for tpr-met and c-met expression. Expression of tpr-met mRNA in the samples was performed by two reverse transcriptase polymerase chain reaction (RT-PCR) assays, with excellent correlation. The specificity of both methods was confirmed by direct sequencing of the PCR products of the MNNG-HOS cell line, which is known to contain the rearrangement. The level of c-met expression was assessed using semi-quantitative RT-PCR assays and immunohistochemistry (IHC). None of the normal gastric mucosal or gastric adenocarcinoma samples expressed tpr-met mRNA, as determined by both RT-PCR assays. Seventy per cent of the adenocarcinomas showed overexpression of c-met, according to elevated c-met mRNA levels, compared with the expression level of normal gastric mucosa. A significant correlation was found between the level of c-met mRNA and protein expression. In conclusion, these results strongly suggest that tpr-met activation does not play a role in Caucasian gastric carcinogenesis, while overexpression of the c-met gene occurs in the majority of Caucasian gastric adenocarcinomas.

Difference in patterns of Met expression in papillary thyroid carcinomas and nonneoplastic thyroid tissue.

Met protein is a tyrosine kinase receptor for hepatocyte growth factor (HGF). c-Met has morphogenic, mitogenic, and motogenic properties and is overexpressed in many solid tumors. We studied c-met mRNA and protein expression in papillary thyroid carcinomas and nonneoplastic thyroid tissue. The c-met mRNA was detected in all biopsies by reverse transcriptase-polymerase chain reaction and by hybridization of complex cDNA probes to a c-met-specific DNA fragment in a dot blot array. Immunohistochemistry on fresh frozen biopsies showed Met protein localized along the basal cell membrane of normal thyrocytes in 32 of 35 nonneoplastic thyroid tissue specimens, sometimes associated with weak cytoplasmic reactivity but without apical cell membrane staining. In papillary carcinomas an increased Met protein expression was seen, comprising a cytoplasmic (33 of 49) and apical cell membrane (24 of 49) immunoreactivity, whereas only 1 of 49 biopsies showed basal cell membrane staining. A 145-kDa Met-specific band was detected by Western immunoblotting on protein extracts from papillary carcinomas. The tight junction protein zona occludens-1 (ZO-1), studied by immunohistochemistry, was weakly expressed along the apical cell membrane in 10 nonneoplastic biopsies. In contrast, increased and cytoplasmic/apical membranous ZO-1 immunostaining was seen in 11 of 15 papillary carcinomas. Nuclear ZO-1 staining was present in a few papillary carcinomas with partial dedifferentiation. The concomitant overexpression and subcellular redistribution of Met and ZO-1 proteins indicate a change in cell polarity in papillary carcinomas compared to nonneoplastic thyroid tissue. These observations may reflect an important feature of the tumorigenesis of papillary thyroid carcinomas. No significant association was found between semiquantitative immunohistochemical assessment of Met protein and clinical parameters in papillary carcinoma patients.

Overexpression of the c-met Protooncogene in Human Gastric Carcinoma - Correlation to Clinical Features

Overexpression of hepatocyte growth factor receptor (c-met) has been detected in many human tumors. To investigate the possible involvement of c-met in human gastric carcinogenesis, we examined c-met expression in 45 patients with gastric carcinoma using Northern blot analysis, reverse transcription-polymerase chain reaction (RT-PCR), and immunohistochemical staining. The c-met mRNA expression was increased twofold and sevenfold in gastric carcinoma tissues compared to the adjacent normal tissues by Northern blot analysis and RT-PCR, respectively. In the immunohistochemical study, c-met protein was detected in 32 of 45 (71.1%) patients, with marked overexpression in gastric carcinoma compared with matched normal gastric tissues. The c-met-positive immunoreactivities were more frequently encountered in serosa-exposed and serosa-infiltrating gastric cancer (p = 0.003). In addition, tumor stage was another statistically significant parameter that was observed between the two groups (p = 0.02). Multivariate analyses revealed that the tumor stage (p = 0.014) and c-met overexpression (p = 0.031) were independently correlated with survival. These data suggest that overexpression of c-met may play a part in gastric carcinogenesis and may represent a prognostic factor for gastric cancer.

Role of HGF/c-met system in invasion and metastasis of oral squamous cell carcinoma cells in vitro and its clinical significance.

We examined the role of the hepatocyte growth factor (HGF)/c-met system on invasion and metastasis of oral squamous cell carcinoma (SCC) cells. In monolayer culture, exogenous HGF marginally affected the growth of oral SCC cells (BHY, HN, IH) and human gingival epithelial cells (GE). In type I collagen matrix, however, HGF significantly enhanced the invasive growth of the cancer cells (p < 0.05). We detected the expression of c-met (HGF receptor) mRNA in all of the cancer cells, but not in human gingival fibroblasts (GF). Oral SCC cells did not secret HGF protein into the medium, but GF secreted a large amount of HGF protein (15 ng/ml). Furthermore, HGF markedly enhanced the migration of cancer cells in a Transwell invasion chamber. Then, we examined the serum levels of HGF in oral SCC patients, or HGF concentrations in oral cancer tissues. Serum levels of HGF in the patients were significantly higher than those in healthy volunteers (p < 0.05). After initial treatment, all of the tumor-free survivors showed a marked decline in the serum HGF levels. Furthermore, HGF concentrations in metastatic cancer tissues were significantly higher than those of non-metastatic cancer tissues and normal gingiva (p < 0.01). These results suggest that HGF plays an important role in invasion and metastasis of oral SCC cells as a paracrine factor, and an elevated HGF level in the cancer tissue can be a predictive marker for metastasis formation in patients with oral SCC.

Hepatocyte Growth Factor Concentration in Maternal and Umbilical Cord Blood Samples and Expression in Fetal Liver

To determine whether human placenta secretes hepatocyte growth factor (HGF) and could influence fetal liver development. Expression of HGF and c-met mRNA in paired samples of first- and second-trimester fetal liver and placenta was compared using a quantitative ribonuclease protection assay. Serum HGF concentration in 30 samples of paired umbilical and maternal blood from term pregnancies was evaluated using an enzyme-linked immunosorbent assay. HGF and c-met mRNA were expressed at similar levels in liver and placenta, with expression increasing from 9 to 16 weeks' gestation. Median serum HGF values were 1.4 ng/mL (maternal venous), 1.2 ng/mL (cord venous), and 1.3 ng/mL (cord arterial). The maternal venous HGF levels were significantly higher than fetal venous levels (P =.02). This study does not support the hypothesis that the placenta secretes HGF, because maternal serum levels were higher than fetal and there was no significant difference between umbilical arterial and venous samples. Fetal liver expresses abundant HGF mRNA during the first and second trimester and expression increases in line with receptor (c-met) expression, suggesting that hepatic growth and development are independent of placental HGF.

Expression of Constitutively Active c-MET Receptor in Human Choriocarcinoma

Objective: The c-MET oncogene encodes the transmembrane tyrosine kinase receptor for hepatocyte growth factor (HGF). Recently, either HGF or c-MET has been knocked out in the mouse, and the mutation is associated with defects in the development of the placenta by means of the reduction of trophoblast cells. We examined the role of c-MET in malignant transformation of trophoblast cells. Methods: In four human choriocarcinoma cell lines, GCH-1, GCH-1m, NUC-1 and SCH, the expression of HGF and c-MET was analyzed by RT-PCR and Western blotting using anti-c-MET antibody and antiphosphotyrosine antibody. Results: RT-PCR analysis showed that no cell lines expressed HGF, however all the cell lines revealed the expression of c-MET mRNA. c-MET receptor was expressed and also tyrosine-phosphorylated constitutively in these cell lines by Western blotting. Conclusion: These results suggest that c-MET may be involved in the growth and behavior of human choriocarcinoma although an autocrine fashion of HGF is unlikely.

U‐PA and c‐MET mRNA expression is co‐ordinately enhanced while hepatocyte growth factor mRNA is down‐regulated in human hepatocellular carcinoma

Hepatocyte growth factor/scatter factor (HGF/SF) is one of the most important humoral mediators of liver regeneration. It is potentially related to molecular mechanisms of hepatocarcinogenesis via a paracrine system involving its cellular receptor, c-met. In this study, the expression patterns of HGF and c-met were evidenced by multiplex RT-PCR in different specimens of human hepatic tissues (n = 71). A significant increase of c-met mRNA expression was detected in hepatitis (P = 0.001), cirrhosis (P = 0.006), and hepatocellular carcinoma (HCC) tissue (P = 0.003) compared with normal parenchyma and steatosis. HGF mRNA expression was significantly higher only in hepatitis (P = 0.01). Over-expression of c-met mRNA and under-expression of HGF mRNA were detected in the HCCs compared with the corresponding peri-tumoral tissues. Neither HGF nor c-met expression was related to age, sex, tumor size, grading, presence of pseudocapsula, and proliferative activity of the malignant hepatocytes. A significant inverse correlation was found between c-met mRNA expression level and survival (in months) of patients (P = 0.007), as previously shown for urokinase-type plasminogen activator (u-PA) mRNA (P = 0.027). In addition, c-met mRNA expression was strictly associated with u-PA mRNA level in HCC samples (P = 0.001). These data show that a loss of balance concerning HGF, c-met, and u-PA mRNA expression occurs during hepatocarcinogenesis. Particularly, up-regulation of c-met and u-PA mRNA transcription appears to be coordinately regulated, and their levels of expression are inversely correlated with survival; they must therefore play an important role in the development and progression of human HCC and may also be relevant prognostic markers. Int. J. Cancer 87:644–649, 2000. © 2000 Wiley-Liss, Inc.

Mechanisms regulating norgestomet inhibition of endometrial gland morphogenesis in the neonatal ovine uterus

In many species, endometrial gland adenogenesis occurs neonatally in an ovary- and steroid-independent manner. Chronic exposure of the developing neonatal ovine uterus to norgestomet (NOR) from birth permanently ablates endometrial gland morphogenesis or adenogenesis, creating an adult ovine uterine gland knockout (UGKO) phenotype. This study was conducted to determine the mechanism(s) whereby NOR inhibits adenogenesis in the neonatal ewe. Ewe lambs received no implant or a NOR implant at birth and on postnatal day (PND) 14, and they were necropsied on PND28. Histological analyses of the tracts indicated NOR exposure specifically inhibited endometrial adenogenesis, but no histoarchitectural differences were observed in the oviduct, cervix, or vagina. No effect of NOR treatment was detected on proliferating cell nuclear antigen (PCNA) expression in the endometrial luminal epithelium (LE), stroma, or myometrium. In control (CX) ewes, estrogen receptor α (ER-α) and progesterone receptor (PR) mRNA and protein were expressed strongly in nascent and proliferating glandular epithelium (GE) but were undetected in epithelium of NOR uteri. Expression of c-met and fibroblast growth factor receptor 2IIIb (FGFR2IIIb) mRNA was detected in the LE and GE of CX uteri. In NOR uteri, c-met was expressed in the LE similar to CX uteri, but FGFR2IIIb mRNA levels were lower than in the LE of CX uteri. Uterine hepatocyte growth factor (HGF), the ligand for c-met, and FGFR2IIIb mRNA expression was substantially lower in NOR ewes, but expression of FGF-7 and FGF-10 mRNAs, ligands for FGFR2IIIb, was unaffected. These results indicate that NOR disrupts endometrial adenogenesis by ablating epithelial ER-α expression and altering expression of paracrine growth factors and/or receptors involved in epitheliomesenchymal interactions. Likewise, these mechanisms are proposed to be important regulators of normal uterine gland morphogenesis in the neonate. Mol. Reprod. Dev. 57:67–78, 2000. © 2000 Wiley-Liss, Inc.

Modulation of estrogen production and 17beta-hydroxysteroid dehydrogenase-type 1, cytochrome P450 aromatase, c-met, and protein kinase Balpha messenger ribonucleic acid content in rat ovarian granulosa cells by hepatocyte growth factor and follicle-stimulating hormone.

Hepatocyte growth factor (HGF) suppresses FSH-dependent estradiol-17beta (E(2)) production in ovarian granulosa cells (GC). The mechanisms of action for HGF in GC are unknown; however, activation of the HGF receptor, c-Met, can induce c-Akt/protein kinase B (PKB)-mediated signal transduction in nonovarian cells. Using immature rat GC, the present study investigated the effects of HGF within the estrogen biosynthetic pathway, concomitant with changes in c-Met and PKBalpha mRNA expression. Granulosa cells were incubated with androstenedione and FSH, HGF, and/or dibutyryl-cAMP (Bu(2)-cAMP). Follicle-stimulating hormone and Bu(2)-cAMP each stimulated estrone (E(1)) and E(2) synthesis at 48 h. Hepatocyte growth factor suppressed FSH-dependent E(2), but not E(1), synthesis. Semiquantitative reverse transcription-polymerase chain reaction showed that HGF impaired FSH-supported 17beta-hydroxysteroid dehydrogenase type-1 (17beta-HSD) and cytochrome P450 aromatase (P450arom) mRNA levels. Hepatocyte growth factor did not reduce E(2) synthesis or 17beta-HSD and P450arom mRNA expression in the presence of Bu(2)-cAMP at 48 h. The FSH and HGF each down-modulated c-Met mRNA accumulation, whereas Bu(2)-cAMP increased c-Met mRNA content. Between 0 and 48 h a biphasic change in PKBalpha mRNA content occurred with either FSH or HGF; however, PKBalpha mRNA accumulation was augmented by HGF. Collectively, results suggest that HGF can suppress E(2) production in GC by disrupting cAMP-dependent 17beta-HSD and P450arom. Changes in c-Met and PKBalpha mRNA content provide a potential link between HGF signaling and the FSH-dependent mechanisms that control the steroidogenic differentiation of GC.

U-PA and c-MET mRNA expression is co-ordinately enhanced while hepatocyte growth factor mRNA is down-regulated in human hepatocellular carcinoma

Hepatocyte growth factor/scatter factor (HGF/SF) is one of the most important humoral mediators of liver regeneration. It is potentially related to molecular mechanisms of hepatocarcinogenesis via a paracrine system involving its cellular receptor, c-met. In this study, the expression patterns of HGF and c-met were evidenced by multiplex RT-PCR in different specimens of human hepatic tissues (n = 71). A significant increase of c-met mRNA expression was detected in hepatitis (P = 0.001), cirrhosis (P = 0.006), and hepatocellular carcinoma (HCC) tissue (P = 0.003) compared with normal parenchyma and steatosis. HGF mRNA expression was significantly higher only in hepatitis (P = 0.01). Over-expression of c-met mRNA and under-expression of HGF mRNA were detected in the HCCs compared with the corresponding peri-tumoral tissues. Neither HGF nor c-met expression was related to age, sex, tumor size, grading, presence of pseudocapsula, and proliferative activity of the malignant hepatocytes. A significant inverse correlation was found between c-met mRNA expression level and survival (in months) of patients (P = 0.007), as previously shown for urokinase-type plasminogen activator (u-PA) mRNA (P = 0.027). In addition, c-met mRNA expression was strictly associated with u-PA mRNA level in HCC samples (P = 0.001). These data show that a loss of balance concerning HGF, c-met, and u-PA mRNA expression occurs during hepatocarcinogenesis. Particularly, up-regulation of c-met and u-PA mRNA transcription appears to be coordinately regulated, and their levels of expression are inversely correlated with survival; they must therefore play an important role in the development and progression of human HCC and may also be relevant prognostic markers.

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.