Fibroblast Growth Factor Gene Expression Research Articles

Basic fibroblast growth factor messenger ribonucleic acid levels in human placentas from normal and pathological pregnancies

This study was designed to determine whether basic fibroblast growth factor (bFGF) gene expression in human placenta varies as a function of gestational age and to evaluate whether bFGF synthesis might be altered in pathological pregnancies. Moreover, we also investigated whether human placental cells express the bFGF receptor gene. The presence of mRNA for bFGF and its receptor was demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR) performed on total RNA derived from human placental cells at different times of culture. Levels of bFGF mRNA were determined by competitive RT-PCR in human placental tissues collected at the beginning and at the end of pregnancy. Competitive RT-PCR was also employed to evaluate bFGF synthesis in term placentas derived from pregnancies complicated by diabetes. mRNA for both bFGF and its receptor were demonstrated in human placenta starting as early as 8 weeks of pregnancy. Values of bFGF mRNA were significantly higher in first trimester compared with term placentas. Term placentas derived from pregnancies associated with type I diabetes expressed levels of bFGF mRNA higher than those present in normal term placentas. These data demonstrate that bFGF and its receptor are synthesized in human placental cells throughout gestation. Moreover, bFGF gene expression is developmentally regulated. Finally, bFGF might also be partially responsible for the placental alterations observed in pregnancies complicated by diabetes.

Fibroblast growth factor-2 expression is up-regulated after denervation in rat lung tissue

To understand the role of fibroblast growth factor-2 (FGF-2) during the denervation–reinnervation processes which occur after lung transplantation, we studied FGF-2 gene expression in a rat lung denervation model. The temporal profile of FGF-2 mRNA in denervated rat lungs was quantitatively assessed by competitive reverse transcription polymerase chain reaction (RT-PCR) method. The level of FGF-2 mRNA was consistently higher in denervated lungs, showing a peak value on the 5th post-operative day. Immunohistochemical analysis with an anti-FGF-2 monoclonal antibody disclosed immunoreactivity in Schwann cells at the distal severed end of the nerve fascicle located at the lung hilus, 1 week post-surgery. This study indicates that FGF-2 gene expression is up-regulated following denervation and suggests possible roles of FGF-2 in the reinnervation process of lung tissue.

Oncostatin M induces basic fibroblast growth factor expression in endothelial cells and promotes endothelial cell proliferation, migration and spindle morphology.

Oncostatin M (OSM), a pleiotropic cytokine originally isolated from supernatants of the U937 histiocytic lymphoma cell line, has been shown to have regulatory effects on a wide variety of cultured and tumor cells. We investigated the effects of OSM on basic fibroblast growth factor (bFGF) gene expression in bovine arterial endothelial (BAE) cells. Levels of bFGF mRNA transcripts were low in uninduced BAE cells, were maximal at 8 hours of exposure to OSM, and returned to control levels by 24 hours. Induction of bFGF mRNA transcripts by OSM was dose-dependent. Nuclear transcriptional run-on analysis demonstrated that exposure of BAE cells to OSM stimulated bFGF gene transcription. OSM treatment of BAE cells enhanced the synthesis of bFGF protein as determined by ELISA assays. Immunocytochemistry studies demonstrated the presence of low levels of bFGF protein within the cytoplasm in uninduced cells. After stimulation for 8 hours with OSM there was significant staining for bFGF in the cytoplasm. However, 24 hours after exposure to OSM, bFGF antigen was located only within the nuclei. Western blot analysis demonstrated that OSM stimulated predominantly the synthesis of a 22 kDa form of bFGF. In addition, OSM stimulated endothelial cell proliferation and migration as well as acquisition of a spindle shape. Phosphorothioate antisense oligonucleotide directed against bFGF inhibited OSM induced BAE cell proliferation and spindle shape formation but had only a minimal effect on migration. The levels of the 22 kDa form of bFGF were reduced by antisense treatment indicating that OSM induced proliferation and morphology change is likely to be regulated by intracellular bFGF. Our studies suggest that OSM released at sites of vascular injury could stimulate angiogenesis by inducing bFGF synthesis, endothelial cell proliferation and migration.

In vitro amplification of human basic fibroblast growth factor mRNA by RNA-specific exon-junction primers.

Highly sensitive and RNA-specific primers for the determination of human basic fibroblast growth factor (bFGF) gene expression by RT-PCR were identified. The RNA-specific primers could amplify bFGF mRNA from 10 pg to 1 ng of total cellular RNA without interfering with the presence of genomic DNA of the cell. The feasible temperatures of the primers annealed to the template were 55 degrees C, 60 degrees C and 65 degrees C. In addition, different locations of primers on the bFGF mRNA molecule yielded distinct amounts of RT-PCR products from the same concentration of RNA, suggesting that the mRNA secondary structure of bFGF affected the RT-PCR. Owing to high sensitivity and specificity of the primers to bFGF RNA, the RNA-specific primers may be potentially utilized for the determination of human bFGF gene expression by in situ RT-PCR.

Basic fibroblast growth factor expression and tenascin C immunoreactivity after partial unilateral hemitransection of the rat brain

Basic fibroblast growth factor (bFGF) gene expression as well as its immunoreactivity were studied after partial unilateral hemitransection of the rat brain during a time course of 24 h, 72 h, 7 and 14 days. The mechanical injury resulted in a global increase of bFGF gene expression at the 24-h time interval. This global increase was seen at the ipsilateral site at the level of the lesion as well as rostral to the lesion in the ipsilateral hemisphere. The upregulation in bFGF gene expression was in most of the areas investigated due to an upregulation in glial cells as seen by means of nonradioactive in situ hybridization compared with immunocytochemistry for glial fibrillary acidic protein (GFAP). Basic FGF immunoreactivity (IR) was increased around the lesion in glial cell nuclei 7 days after the injury. This increase was also detected in GFAP positive glial cells surrounding small vessels in the lesioned area. Moreover, in the present paper we demonstrate increased tenascin immunoreactivity in the lesioned area 7 days after injury. The tenascin IR was increased at the edges of the lesion as well as in vessel like structures. The tenascin IR was partially codistributed with GFAP IR in the lesioned area. The lesion was also characterized by an increase in vimentin IR as well as in laminin IR. It is suggested that the observed changes in the expression of bFGF, matrix proteins (laminin, tenascin) and intermediate filaments (vimentin) are involved in (a) tissue repair, (b) protection of neuronal cells from excitotoxic influences and (c) formation of new vessels in the lesioned area.

Promoter regions involved in density-dependent regulation of basic fibroblast growth factor gene expression in human astrocytic cells.

Expression of mitogenic basic fibroblast growth factor (bFGF) in the central nervous system is inhibited by direct cell contact and is implicated in reactive and neoplastic transformation of astrocytes. The molecular mechanisms controlling expression of bFGF were examined in cultures of human astrocytes. Cell-density-dependent depletion of bFGF mRNA levels parallels changes in bFGF gene protein. Regulation of transcription of a bFGF luciferase reporter gene containing an upstream region (bp -1800 to +314) of the bFGF gene promoter mimicks the density-dependent regulation of the endogenous bFGF gene in transfected astrocytes. Deletion analysis has identified a fragment (bp -650 to -513) and sequences further downstream (bp -274 to +314) as the regions required for the regulation of bFGF gene activity by cell density. Unlike in astrocytes, changing the cell density of glioma cell cultures does not affect the levels of bFGF protein and mRNA. bFGF luciferase constructs were expressed at the same level in high- or low-density cultures of glioma cells, indicating altered regulation of the bFGF gene promoter. Electrophoretic mobility shift assays showed binding of nuclear proteins to a fragment of bFGF gene promoter from bp -650 to -453. This binding was abolished by a deletion of the upstream cell-density-responsive region (bp -650 to -512). Binding was observed with nuclear extracts from subconfluent astrocytes but was reduced in extracts from confluent astrocytes. Our results indicate that induction of bFGF in astrocytes upon reduction of cell density is mediated transcriptionally by positive trans-acting factors interacting with bFGF promoter. In contrast, nuclear proteins from glioma cells bind to the promoter region from bp -650 to -453 independent of cell density. Thus, the constitutive binding of trans-acting factor(s) to the region of the bFGF promoter from bp -650 to -453 may be responsible for the continuous expression of bFGF that leads to the uncontrolled growth of glioma cells.

Clinical significance of vascular endothelial growth factor and basic fibroblast growth factor gene expression in liver tumor

Hepatocellular carcinoma (HCC) is a typical hypervascular tumor. However, the relationship between the vascularity of HCC and the expression of angiogenic factors has not been investigated. In addition, no detailed studies have examined the possible involvement of angiogenic factors in the grade of malignancy of HCC. The aim of this study was to determine which angiogenic factors regulate tumor angiogenesis and contribute to the invasive ability of liver tumors, especially of HCC. Northern blot analysis was used to examine the transcriptional expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), and acidic FGF in resected surgical specimens (20 HCC and 9 metastatic liver tumors). Correlations between messenger RNA (mRNA) expression and arteriographic findings, as well as histopathological findings, were evaluated. Immunohistochemistry was performed to identify the localization of cells expressing VEGF in HCC. Higher levels of VEGF mRNA were observed in 12 of 20 HCC and 2 of 9 metastatic liver tumors than in corresponding nontumorous tissues. The degree of VEGF mRNA expression was significantly correlated with the intensity of tumor staining in angiograms (P <.01). On immunohistochemical observation, VEGF protein was intensely detected in HCC cells. Furthermore, basic FGF mRNA was detected in 9 of 20 HCC and was related to the capsular infiltration of cancer cells (P <.05). In contrast, no significant difference was observed in the very low levels of acidic FGF mRNA found in the tumorous and nontumorous portions of the liver. In conclusion, these results suggest that VEGF contributes to angiogenesis of liver tumors, whereas basic FGF may be involved in the invasion of HCC into the surrounding tissues.

Clinical significance of vascular endothelial growth factor and basic fibroblast growth factor gene expression in liver tumor

Hepatocellular carcinoma (HCC) is a typical hypervascular tumor. However, the relationship between the vascularity of HCC and the expression of angiogenic factors has not been investigated. In addition, no detailed studies have examined the possible involvement of angiogenic factors in the grade of malignancy of HCC. The aim of this study was to determine which angiogenic factors regulate tumor angiogenesis and contribute to the invasive ability of liver tumors, especially of HCC. Northern blot analysis was used to examine the transcriptional expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), and acidic FGF in resected surgical specimens (20 HCC and 9 metastatic liver tumors). Correlations between messenger RNA (mRNA) expression and arteriographic findings, as well as histopathological findings, were evaluated. Immunohistochemistry was performed to identify the localization of cells expressing VEGF in HCC. Higher levels of VEGF mRNA were observed in 12 of 20 HCC and 2 of 9 metastatic liver tumors than in corresponding nontumorous tissues. The degree of VEGF mRNA expression was significantly correlated with the intensity of tumor staining in angiograms (P <.01). On immunohistochemical observation, VEGF protein was intensely detected in HCC cells. Furthermore, basic FGF mRNA was detected in 9 of 20 HCC and was related to the capsular infiltration of cancer cells (P <.05). In contrast, no significant difference was observed in the very low levels of acidic FGF mRNA found in the tumorous and nontumorous portions of the liver. In conclusion, these results suggest that VEGF contributes to angiogenesis of liver tumors, whereas basic FGF may be involved in the invasion of HCC into the surrounding tissues.

Clinical significance of vascular endothelial growth factor and basic fibroblast growth factor gene expression in liver tumor

Hepatocellular carcinoma (HCC) is a typical hypervascular tumor. However, the relationship between the vascularity of HCC and the expression of angiogenic factors has not been investigated. In addition, no detailed studies have examined the possible involvement of angiogenic factors in the grade of malignancy of HCC. The aim of this study was to determine which angiogenic factors regulate tumor angiogenesis and contribute to the invasive ability of liver tumors, especially of HCC. Northern blot analysis was used to examine the transcriptional expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), and acidic FGF in resected surgical specimens (20 HCC and 9 metastatic liver tumors). Correlations between messenger RNA (mRNA) expression and arteriographic findings, as well as histopathological findings, were evaluated. Immunohistochemistry was performed to identify the localization of cells expressing VEGF in HCC. Higher levels of VEGF mRNA were observed in 12 of 20 HCC and 2 of 9 metastatic liver tumors than in corresponding nontumorous tissues. The degree of VEGF mRNA expression was significantly correlated with the intensity of tumor staining in angiograms (P <.01). On immunohistochemical observation, VEGF protein was intensely detected in HCC cells. Furthermore, basic FGF mRNA was detected in 9 of 20 HCC and was related to the capsular infiltration of cancer cells (P <.05). In contrast, no significant difference was observed in the very low levels of acidic FGF mRNA found in the tumorous and nontumorous portions of the liver. In conclusion, these results suggest that VEGF contributes to angiogenesis of liver tumors, whereas basic FGF may be involved in the invasion of HCC into the surrounding tissues. (Hepatology 1996 Mar;23(3):455-64)

Hypoglycemia-induced AP-1 transcription factor and basic fibroblast growth factor gene expression in multidrug resistant human breast carcinoma MCF-7/ADR cells.

We investigated the effect of hypoglycemic treatment on the activation of the AP-1 transcription factors and the regulation of basic fibroblast growth factor (bFGF) gene expression in multidrug resistant human breast carcinoma MCF-7/ADR cells. Northern blot and gel mobility shift assays showed that hypoglycemic treatment induced c-jun and c-fos gene expression, AP-1 binding activity, as well as bFGF gene expression. Moreover, transfected cells expressing high levels of abnormal c-Jun protein exhibited a reduction in the bFGF protein levels compared to parental cells. A potent protein kinase C (PKC) inhibitor, H-7 (60 micrograms/ml) suppressed the stress-induced bFGF gene expression. Our study also demonstrated that H-7 did not facilitate the decay of bFGF mRNA. Thus, the suppression of bFGF gene expression by treatment with H-7 was due to the effect of the drug on the synthesis of bFGF mRNA rather than the stability of bFGF mRNA. Our data suggest that hypoglycemia-induced bFGF gene expression is mediated through the activation of PKC and the AP-1 transcription factors.

Effect of Ionizing Radiation on AP-1 Binding Activity and Basic Fibroblast Growth Factor Gene Expression in Drug-sensitive Human Breast Carcinoma MCF-7 and Multidrug-resistant MCF-7/ADR Cells

We studied the effect of ionizing radiation on the activation of the AP-1 transcription factors and the regulation of basic fibroblast growth factor (bFGF) gene expression in drug-sensitive human breast carcinoma (MCF-7) cells and its drug-resistant variant (MCF-7/ADR) cells. Northern blot and gel mobility shift assays showed that 135 cGy of ionizing radiation induced c-jun and c-fos gene expression, AP-1 binding activity, as well as bFGF gene expression in MCF-7/ADR cells. In MCF-7 cells, however, we observed little/no induction of bFGF gene expression and AP-1 binding activity after the stress. Nevertheless, MCF-7 cells transfected with plasmids containing c-jun gene contain high levels of bFGF protein. H-7 (60 micrograms/ml), a potent protein kinase C (PKC) inhibitor, inhibited the stress-induced AP-1 binding activity and bFGF gene expression in MCF-7/ADR cells. Corroborating this observation, overexpression of PKC alpha induced bFGF gene expression in MCF-7 cells. Taken together, these results suggest that stress-induced bFGF gene expression is mediated through the activation of PKC and AP-1 transcription factors. Differences in the levels of PKC activity and AP-1 binding factors may be responsible for differential expression of bFGF among breast cancer cell lines. Although there are large differences in response to ionizing radiation between MCF-7 and MCF-7/ADR cell lines, we observed no significant differences in radiocytotoxicity between them.

Regulation of basic fibroblast growth factor (bFGF) gene and protein expression following its release from sublethally injured endothelial cells.

Basic fibroblast growth factor (bFGF; FGF-2) lacks a signal sequence and thus is not secreted by classical pathways. It has been speculated that one mode of bFGF release may be injury, either sublethal or lethal; and, transient disruption of the plasma membrane has been shown to release bFGF [Muthukrihnan et al. (1991): J Cell Physiol 148:1-16]. This observation has led to the concept of bFGF as a "wound hormone," involved in tissue integrity and repair. Findings of elevated bFGF following injury in vivo support this concept. Using an in vitro model, we have examined the regulation of bFGF gene expression following its release by sublethal injury. Analysis of bFGF protein by ELISA revealed that scraping subconfluent bovine aortic EC (BAE) released up to 80% of their bFGF. Following scraping, there was a 4- to 10-fold increase in the steady state level of bFGF mRNA, which reached a maximum at 2-3 h. There was a parallel increase in protein so that by 6 h after the scrape-induced release, bFGF levels were restored to those measured prior to scraping. Since bFGF has been reported to induce its own expression, we hypothesized that the released bFGF might be responsible for the increase in bFGF mRNA. However, inclusion of neutralizing antibodies against bFGF had a negligible effect on the scrape-induced increase in bFGF mRNA levels. Because of the important role of transforming growth factor type-beta 1 (TGF-beta 1), the plasminogen/plasminogen activator system, and thrombin in wound healing, we investigated their potential contributions to the increase in bFGF expression. Addition of anti-TGF-beta 1 antibodies, plasminogen activator inhibitor-1 (PAI-1), or the thrombin inhibitory combination of heparin and anti-thrombin III (AT III) to the cells at the time of scraping blocked about 50% of the increase in bFGF mRNA; the effects of these agents were not additive. The suppression of bFGF mRNA was associated with a proportional reduction in bFGF protein. Inclusion of the antagonists for 2 h at the time of scraping led to reduced cell proliferation, suggesting that cell-associated bFGF may be required for recovery and growth. Finally, studies to characterize the molecular mechanisms underlying the increased bFGF mRNA following sublethal injury revealed an increase in the transcriptional activation of bFGF gene. These results indicate that in spite of the fact that bFGF is not a secreted protein, levels of bFGF in the cell are tightly regulated. Furthermore, these findings suggest a role for bFGF in recovery from cell injury.

Opposite Regulation of Basic Fibroblast Growth Factor and Nerve Growth Factor Gene Expression in Rat Cortical Astrocytes Following Dexamethasone Treatment

Growth factors are peptides that exert different activities in the CNS, supporting the survival of different cell populations and playing an important role in the maintenance of cell homeostasis. Much evidence has suggested that these molecules can protect neurons from degeneration induced by mechanical injury or excitotoxic stimuli. Different factors can contribute to the regulation of neurotrophic factor expression in the brain. Such mechanisms may therefore be important in the manipulation of the levels of these peptides in specific brain areas as a therapeutic intervention in acute and chronic neurodegenerative diseases. We have used a primary culture of rat cortical astrocytes to investigate the regulation of basic fibroblast growth factor (bFGF) gene expression in comparison with other neurotrophic molecules. Our results indicate that the glucocorticoid analogue dexamethasone markedly elevates bFGF mRNA levels but reduces the expression of nerve growth factor. The induction of bFGF was transient, as it peaked after 6 h and returned to basal levels within 24 h and was not blocked by coincubation of cycloheximide, thus indicating that it did not require de novo protein synthesis. This effect was also observed in vivo, as systemic injection of dexamethasone (1 or 10 mg/kg) produced a significant increase in the amount of bFGF mRNA in cerebral cortex and hippocampus. The effect we describe can contribute to the regulation of bFGF expression in the brain and may be important in relation to the protective effect exerted by this growth factor in different models of neuronal injury.

Basic fibroblast growth factor and growth factor receptor gene expression in 85% O2-exposed rat lung.

Lungs exposed to elevated O2 concentrations suffer an initial loss of type I pneumocytes, followed by a reparative type II pneumocyte hyperplasia. We hypothesized that type II pneumocyte hyperplasia after exposure of young adult rats to 85% O2 in vivo would be temporally related to 1) an increased concentration of intrapulmonary basic fibroblast growth factor (bFGF), a potent stimulator of type II pneumocyte DNA synthesis in vitro, and 2) an upregulation of pneumocyte receptors for bFGF (FGF-R). Increased rat lung bFGF mRNA, relative to air-exposed control animals, was observed at 4 days of exposure, with no increase at days 6 and 14 of exposure. Parallel changes were observed with bFGF receptor (flg) mRNA. Nuclear runoff assays confirmed increased transcription of both bFGF and flg genes in response to 85% O2, whereas increased translation at 6 days of exposure was confirmed by protein immunoanalysis. Immunohistochemistry demonstrated a broad distribution of bFGF throughout the lung, including the alveolar epithelium, which increased after 6 and 14 days of exposure to 85% O2. Our findings are compatible with a role for bFGF in O2-mediated pneumocyte hyperplasia.

Perinatal asphyxia increases bFGF mRNA levels and DA cell body number in the mesencephalon of rats.

The present investigation was undertaken in order to study the long-term effects of perinatal asphyxia on basic fibroblast growth factor (bFGF) gene expression and the number of dopamine nerve cell bodies in the mesencephalon of the rat. Asphyxia was induced during birth for 19-20 min. A 30% increase in the number of tyrosine-hydroxylase immunoreactive (TH-IR) nerve cell bodies (i.e. dopamine-containing neurones) as well as a 50% increase in bFGF gene expression following asphyxia was found in the substantia nigra/ventral tegmental area 4 weeks after birth. The increase in bFGF mRNA levels may underlie the increase found in the number of dopamine cell bodies. The present results indicate that asphyxia during birth can prime the long-term development of the central nervous system.

Differential regulation of acidic and basic fibroblast growth factor gene expression in fibroblast growth factor-treated rat aortic smooth muscle cells.

The acidic fibroblast growth factor (aFGF) and basic fibroblast growth factor (bFGF) proteins are potent vascular smooth muscle cell (SMC) mitogens that are expressed by endothelial cells and SMCs in vivo. Overexpression of these proteins in transfected cell lines can result in autocrine transformation; therefore, the precise control of fibroblast growth factor gene expression in the vessel wall may be an important mechanism regulating vascular cell growth. In the present study, we demonstrate that bFGF can induce bFGF mRNA expression, but not aFGF mRNA expression, in serum-starved rat aortic SMCs. bFGF autoinduction is maximal at 4 hours, requires de novo RNA and protein synthesis, and is mediated predominantly by a protein kinase C-dependent signaling pathway. Furthermore, aFGF treatment of rat SMCs also increases bFGF mRNA and protein expression; however, aFGF mRNA levels are only slightly modulated. These results suggest that the local release of aFGF or bFGF within the vessel wall could promote a prolonged period of elevated bFGF synthesis. This, in turn, could be of importance in the SMC hyperplasia that occurs in response to vascular injury and during atherosclerotic plaque formation.

Short- and long-term induction of basic fibroblast growth factor gene expression in rat central nervous system following kainate injection

Both RNase protection assay and in situ hybridization were used to investigate the effect of intraperitoneal injection of kainate on the messenger RNA levels for basic fibroblast growth factor in the rat central nervous system. Limbic motor seizures were produced by kainate injection and this event was followed by a significant elevation of basic fibroblast growth factor gene expression in rat hippocampus and striatum 6 h after the convulsant injection. The increase in hippocampus was maximal at 24 h and it was delayed with respect to nerve growth factor induction, which peaked 3 h after kainate injection. Animals that suffered prolonged seizure activity also showed a significant elevation of basic fibroblast growth factor gene expression four and 14 days after kainate, when no changes in nerve growth factor gene expression were observed. We show that, within the hippocampus, the increase of basic fibroblast growth factor messenger RNA was localized in dentate gyrus and the CA1 layer 6 and 24 h after kainate injection. Long-term effects on its gene expression were measurable only in the CA1 hippocampal subfield, where major cell damage and astrocytosis have been reported to occur following kainate-induced seizure activity [Ben-Ari Y. et al. (1981) Neuroscience 7, 1361–1391; Lothman E. W. and Collins R. C. (1981) Brain Res. 218, 299–318; Schwob J. E. et al. (1980) Neuroscience 5, 991–1014]. Indeed, the animals which displayed elevated messenger RNA levels for basic fibroblast growth factor four and 14 days after kainate injection showed a marked induction of messenger RNA expression for the astroglial marker glial fibrillary acidic protein. These results indicate that the glutamate analogue kainate produces short- and long-term increases of basic fibroblast growth factor messenger RNA expression with a specific anatomical pattern. Therefore, the gene expression for this neurotrophic factor is probably regulated by neuronal activity at early points in time, whereas the induction observed at later time points is related to adaptive mechanisms taking place following kainate-induced neuronal degeneration.

The observation of angiogenin and basic fibroblast growth factor gene expression in human colonic adenocarcinomas, gastric adenocarcinomas, and hepatocellular carcinomas.

Using digoxigenin-labelled, synthetic oligonucleotide probe cocktails of angiogenin and bFGF genes, the expression of the two genes was observed by in situ hybridization in ten colonic adenocarcinomas, seven gastric adenocarcinomas, and four hepatocellular carcinomas. The angiogenin gene was expressed in eight of the ten cases of colonic adenocarcinoma and in all of the four cases where dysplastic glands were found. Angiogenin expression was evident in four of the seven cases of gastric adenocarcinoma. bFGF expression was detected in only five of the seven gastric carcinoma cases. The mRNAs for angiogenin and bFGF were mainly cytoplasmic in distribution and were only occasionally seen in the nuclei of the positive cells. Neither the angiogenin gene mRNA nor the bFGF mRNA was expressed in the four cases of hepatocellular carcinoma. It is postulated that the angiogenin gene may play an important role in angiogenesis in colonic adenocarcinomas; in gastric cancers, both angiogenin and bFGF were involved in this process. For hepatocellular carcinomas, neither angiogenin nor bFGF production appeared to be related to angiogenesis.

Localization of mRNA for basic fibroblast growth factor in human placenta.

The site of basic fibroblast growth factor (bFGF) gene expression in human placenta is not known. In situ hybridization using [35S]-labelled riboprobe was employed to localize the sites of expression of bFGF mRNA in placental sections from early and late gestation. Autoradiographic hybridization signal was present in all placental tissue examined, with no significant hybridization with sense control. Basic FGF expression was seen in the syncytiotrophoblast surrounding the placental villi and in or around cytotrophoblast cells in first trimester placenta. At term, the bFGF gene expression was detected in the syncytiotrophoblast and fetal membranes. Strong expression of bFGF mRNA was localized in the smooth muscle cells around the mid and large sized placental vessels. The detection of bFGF mRNA in the placenta during early pregnancy suggests a role for bFGF in angiogenesis, whereas, its expression at term suggests that bFGF may be associated with differentiated functions of the trophoblast.

Effect of methylprednisolone on transforming growth factor-beta, insulin-like growth factor-I, and basic fibroblast growth factor gene expression in the kidneys of NZB/W F1 mice.

The present study was carried out to determine whether transforming growth factor-beta, insulin-like growth factor-I and basic fibroblast growth factor mRNA levels were correlated with disease activity in NZB/W F1 mice, an animal model of systemic lupus erythematosus. Levels of mRNA for these three growth factors increased significantly as nephritis progressed in these mice. At 48 weeks of age, transforming growth factor-beta, insulin-like growth factor-I, and basic fibroblast growth factor mRNA levels showed a 11- (p < 0.001), 10- (p < 0.001), and 8-fold (p < 0.001) increase, respectively, in the renal cortex of NZB/W F1 mice when compared with NZW control mice. In NZW kidneys, these mRNA levels showed little change throughout the study period. At 24 weeks of age, NZB/W F1 mice were divided in 2 groups that received either methylprednisolone or saline injections for 24 weeks. The development of histological lesions and the increase in these growth factor mRNA levels in the kidneys of NZB/W F1 mice were both suppressed by methylprednisolone. These results indicate that the transforming growth factor-beta, insulin-like growth factor and basic fibroblast growth factor may play a role in the progression of murine lupus nephritis and that methylprednisolone may be an effective treatment at the transcription level of these growth factor genes for this type of nephritis.