Fibroblast Growth Factor-2 Upregulation Research Articles

MiR-709 exerts an angiogenic effect through a FGF2 upregulation induced by a GSK3B downregulation

The aim of this study was to identify angiogenic microRNAs (miRNAs) that could be used in the treatment of hindlimb ischemic tissues. miRNAs contained in extracellular vesicles (EVs) deriving from the plasma were analyzed in C57BL/6 mice, which have ischemia tolerance, and in BALB/c mice without ischemia tolerance as part of a hindlimb ischemia model; as a result 43 angiogenic miRNA candidates were identified. An aortic ring assay was employed by using femoral arteries isolated from BALC/c mice and EVs containing miRNA; as a result, the angiogenic miRNA candidates were limited to 14. The blood flow recovery was assessed after injecting EVs containing miRNA into BALB/c mice with hindlimb ischemia, and miR-709 was identified as a promising angiogenic miRNA. miR-709-encapsulating EVs were found to increase the expression levels of the fibroblast growth factor 2 (FGF2) mRNA in the thigh tissues of hindlimb ischemia model BALB/c mice. miR-709 was also found to bind to the 3′UTR of glycogen synthase kinase 3 beta (GSK3B) in three places. GSK3B-knockdown human artery-derived endothelial cells were found to express high levels of FGF2, and were characterized by increased cell proliferation. These findings indicate that miR-709 induces an upregulation of FGF2 through the downregulation of GSK3B.

Fibroblast Growth Factor-2 (FGF-2) Expression in Pterygia Using Cell Spot Arrays.

Fibroblast growth factor (FGF) is a main regulator of cell differentiation, cell migration and angiogenesis in normal and abnormal conjunctiva epithelia, but specific mechanisms of its aberrant expression are yet to be investigated. In the present study, we investigated FGF-2 protein expression within several pterygia. Using a liquid-based cytology assay, we obtained cell specimens from pterygia and healthy tissues directly from patients. A combination of immunocytochemistry followed by digital image analysis showed significant overexpression of FGF-2 in all the examined pterygia. In 30/60 (50%) cases there were high levels of staining intensity, whereas in the remaining 30/60 (50%) cases there were moderate levels of expression. FGF-2 levels of the control group were significantly lower in comparison with the pterygia group. There was no significant correlation between FGF-2 levels and either sex or location of the pterygium. FGF-2 levels had a significant correlation with morphological characteristics of the pterygia. More specifically, FGF-2 levels were significantly higher in the pterygia with a fleshy morphology. Interestingly, recurrent lesions demonstrated high expression levels. An overexpression of FGF-2 has been observed frequently in pterygia, where it may play a crucial role in determining the lesion’s progression. FGF-2 upregulation correlates with the morphology of pterygia and its tendency to recur. Cell spot analysis based on liquid-based cytology is a simple, yet effective, method for detecting a broad spectrum of protein markers and could be useful in analyzing potential pterygia patient samples.

CircPDE7B/miR-661 axis accelerates the progression of human keloid fibroblasts by upregulating fibroblast growth factor 2 (FGF2).

Circular RNAs (circRNAs) are implicated in keloidogenesis and development. We aimed to investigate the role of a new identified phosphodiesterase 7B-derived circRNA (hsa_circ_0002198; henceforth named as PDE7B) in human keloid fibroblasts (HKFs) and to further confirm its mechanism via competing endogenous RNA (ceRNA) network. Transcriptional and translational levels of circPDE7B, microRNA (miR)-661, fibroblast growth factor 2 (FGF2), cleaved caspase3, B-cell lymphoma (bcl)-2, and bcl-2-associated X protein (bax) were detected by real-time quantitative PCR and western blotting. Relationship among circPDE7B, miR-661, and FGF2 was confirmed by bioinformatics algorithm, dual-luciferase reporter assay, RNA immunoprecipitation, RNA pull-down assay, and Spearman's rank correlation analysis. Cell progression was measured by cell counting kit-8 assay, 5-ethynyl-2-deoxyuridine assay, transwell assays, and flow cytometry. Expression of circPDE7B was upregulated in human keloid tissues and HKFs, accompanied with miR-661 downregulation and FGF2 upregulation. High circPDE7B accelerated proliferation, migration, and invasion, and inhibited apoptosis. These effects were paralleled with increased bcl-2 and decreased cleaved caspase3 and bax. Moreover, low circPDE7B played opposite effects to high circPDE7B. Restoring miR-661 could suppress HKFs progression, while blocking miR-661 could facilitate that. Notably, miR-661 was directly sponged by circPDE7B and then directly governed FGF2 gene expression. Deleting miR-661 and re-expressing FGF2 both abrogated the suppression of circPDE7B knockdown in HKFs progression. In conclusion, circPDE7B might contribute to HKFs progression via functioning as ceRNA for miR-661, suggesting a novel circPDE7B/miR-661/FGF2 pathway underlying keloid formation and treatment.

Upregulation of fibroblast growth factor 2 contributes to endometriosis through SPRYs/DUSP6/ERK signaling pathway

Previous studies report that fibroblast growth factor 2 (FGF2) modulates Sproutys (SPRYs)/dual specificity phosphatase 6 (DUSP6)/extracellular signal-regulated kinase (ERK) signaling pathway in endometrial glandular epithelial cells. However, its role in endometriosis remains unclear. The expression patterns and localization of related proteins in endometrium patients’ samples were determined using quantitative reverse transcription PCR, Western blotting, and immunohistochemistry, respectively. Human endometrial stromal cells (HESCs) were isolated and transfected with small interfering RNA (siRNA) targeting FGF2 (FGF2-siRNA). Cell viability was determined using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. It was found that FGF2 mRNA and protein levels were increased in the ectopic endometrium, whilst the mRNA and protein levels of SPRYs/DUSP6/ERK signaling pathway related-genes were dysregulated. Spearman’s rank correlation analysis revealed a negative correlation between FGF2 and SPRYs/DUSP6 signaling pathway-related proteins. In vitro study demonstrated that FGF2 silencing suppressed cell proliferation. Our results suggest that FGF2 upregulation might contribute to endometriosis via the regulation of the SPRYs/DUSP6/ERK signaling pathway.

The HPA/SDC1 axis promotes invasion and metastasis of pancreatic cancer cells by activating EMT via FGF2 upregulation.

Pancreatic cancer is characterized by the absence of early specific clinical symptoms, accompanied with rapid metastasis and invasion. It is one of the most prevalent types of cancer and more importantly, one of the most common types of malignant cancer with the highest mortality rate of all cancer types. The heparanase (HPA)/syndecan-1 (SDC1) axis has been reported to promote tumor growth, invasion, metastasis and angiogenesis in a variety of cancer types; however, studies into the role and mechanism of the HPA/SDC1 axis in pancreatic cancer are limited. The present study aimed to investigate the biological function and clinical significance of the HPA/SDC1 axis in pancreatic cancer. The results demonstrated that HPA is elevated in pancreatic cancer tissues and cell lines, and that its high expression was associated with poor prognosis. HPA was revealed to mediate an increase in fibroblast growth factor 2 (FGF2) expression by upregulating the expression of SDC1. Conversely, silencing HPA mediated the suppression of FGF2 expression. Furthermore, upregulated FGF2 was observed to increase the expression of downstream Palladin proteins by activating the PI3K/Akt signaling pathway and also lead to the activation of epithelial-mesenchymal transition (EMT). Subsequently, EMT was found to promote the migration and invasion of pancreatic cancer cells. In summary, the HPA/SDC1 axis was revealed to serve an important role in the regulation of FGF2, and was found to promote the invasion and metastasis of pancreatic cancer cells. These findings indicated that the HPA/SDC1 axis may be used as an effective therapeutic target for pancreatic cancer.

Bradykinin B2 Receptor Contributes to Inflammatory Responses in Human Endothelial Cells by the Transactivation of the Fibroblast Growth Factor Receptor FGFR-1.

Elevated levels of bradykinin (BK) and fibroblast growth factor-2 (FGF-2) have been implicated in the pathogenesis of inflammatory and angiogenic disorders. In angiogenesis, both stimuli induce a pro-inflammatory signature in endothelial cells, activating an autocrine/paracrine amplification loop that sustains the neovascularization process. Here we investigated the contribution of the FGF-2 pathway in the BK-mediated human endothelial cell permeability and migration, and the role of the B2 receptor (B2R) of BK in this cross-talk. BK (1 µM) upregulated the FGF-2 expression and promoted the FGF-2 signaling, both in human umbilical vein endothelial cells (HUVEC) and in retinal capillary endothelial cells (HREC) by the activation of Fibroblast growth factor receptor-1 (FGFR-1) and its downstream signaling (fibroblast growth factor receptor substrate: FRSα, extracellular signal–regulated kinases1/2: ERK1/2, and signal transducer and activator of transcription 3: STAT3 phosphorylation). FGFR-1 phosphorylation triggered by BK was c-Src mediated and independent from FGF-2 upregulation. Either HUVEC and HREC exposed to BK showed increased permeability, disassembly of adherens and tight-junction, and increased cell migration. B2R blockade by the selective antagonist, fasitibant, significantly inhibited FGF-2/FGFR-1 signaling, and in turn, BK-mediated endothelial cell permeability and migration. Similarly, the FGFR-1 inhibitor, SU5402, and the knock-down of the receptor prevented the BK/B2R inflammatory response in endothelial cells. In conclusion, this work demonstrates the existence of a BK/B2R/FGFR-1/FGF-2 axis in endothelial cells that might be implicated in propagation of angiogenic/inflammatory responses. A B2R blockade, by abolishing the initial BK stimulus, strongly attenuated FGFR-1-driven cell permeability and migration.

Locally produced estrogen through aromatization might enhance tissue expression of pituitary tumor transforming gene and fibroblast growth factor 2 in growth hormone-secreting adenomas.

Aromatase, a key enzyme in local estrogen synthesis, is expressed in different pituitary tumors including growth hormone (GH)-secreting adenomas. We aimed to evaluate aromatase, estrogen receptor α (ERα), estrogen receptor β (ERβ), pituitary tumor transforming gene (PTTG), and fibroblast growth factor 2 (FGF2) expressions in GH-secreting adenomas, and investigate their correlation with clinical, pathologic, and radiologic parameters. This cross-sectional study was conducted in a tertiary center in Turkey. Protein expressions were determined via immunohistochemical staining in ex vivo tumor samples of 62 patients with acromegaly and ten normal pituitary tissues. Concordantly increased aromatase, PTTG, and FGF2 expressions were detected in the tumor samples as compared with controls (p<0.001 for all). None of the tumors expressed ERα while ERβ was detected only in mixed somatotroph adenomas. Aromatase, ERβ, PTTG expressions were not significantly different between patients with and without remission (p>0.05 for all). FGF2 expression was significantly higher in patients without postoperative and late remission (p=0.002 and p=0.012, respectively), with sphenoid bone invasion, optic chiasm compression, and somatostatin analog resistance (p=0.005, p=0.033, and p=0.013, respectively). Aromatase, PTTG and FGF2 expressions were positively correlated with each other (r=0,311, p=0.008 for aromatase, FGF2; r=0.380, p=0.001 for aromatase, PTTG; r=0.400, p=0.001 for FGF2, PTTG). PTTG-mediated FGF2 upregulation is associated with more aggressive tumor features in patients with acromegaly. Also, locally produced estrogen through aromatization might have a role in this phenomenon.

Differential cellular FGF-2 upregulation in the rat facial nucleus following axotomy, functional electrical stimulation and corticosterone: a possible therapeutic target to Bell's palsy.

BackgroundThe etiology of Bell's palsy can vary but anterograde axonal degeneration may delay spontaneous functional recovery leading the necessity of therapeutic interventions. Corticotherapy and/or complementary rehabilitation interventions have been employed. Thus the natural history of the disease reports to a neurotrophic resistance of adult facial motoneurons leading a favorable evolution however the related molecular mechanisms that might be therapeutically addressed in the resistant cases are not known. Fibroblast growth factor-2 (FGF-2) pathway signaling is a potential candidate for therapeutic development because its role on wound repair and autocrine/paracrine trophic mechanisms in the lesioned nervous system.MethodsAdult rats received unilateral facial nerve crush, transection with amputation of nerve branches, or sham operation. Other group of unlesioned rats received a daily functional electrical stimulation in the levator labii superioris muscle (1 mA, 30 Hz, square wave) or systemic corticosterone (10 mgkg-1). Animals were sacrificed seven days later.ResultsCrush and transection lesions promoted no changes in the number of neurons but increased the neurofilament in the neuronal neuropil of axotomized facial nuclei. Axotomy also elevated the number of GFAP astrocytes (143% after crush; 277% after transection) and nuclear FGF-2 (57% after transection) in astrocytes (confirmed by two-color immunoperoxidase) in the ipsilateral facial nucleus. Image analysis reveled that a seven days functional electrical stimulation or corticosterone led to elevations of FGF-2 in the cytoplasm of neurons and in the nucleus of reactive astrocytes, respectively, without astrocytic reaction.ConclusionFGF-2 may exert paracrine/autocrine trophic actions in the facial nucleus and may be relevant as a therapeutic target to Bell's palsy.

Amnion-Derived Mesenchymal Stromal Cells Show Angiogenic Properties but Resist Differentiation into Mature Endothelial Cells

Mesenchymal stromal cells derived from the human amnion (hAMSC) currently play an important role in stem cell research, as they are multipotent cells that can be isolated using noninvasive methods and are immunologically tolerated in vivo. The objective of this study was to evaluate their endothelial differentiation potential with regard to a possible therapeutic use in vascular diseases. hAMSC were isolated from human term placentas and cultured in Dulbecco's modified Eagle's medium (DMEM) (non-induced hAMSC) or endothelial growth medium (EGM-2) (induced hAMSC). Induced hAMSC changed their fibroblast-like toward an endothelial-like morphology, and were able to take up acetylated low-density lipoprotein and form endothelial-like networks in the Matrigel assay. However, they did not express the mature endothelial cell markers von Willebrand factor and vascular endothelial-cadherin. Gene expression analysis revealed that induced hAMSC significantly downregulated pro-angiogenic genes such as tenascin C, Tie-2, vascular endothelial growth factor A (VEGF-A), CD146, and fibroblast growth factor 2 (FGF-2), whereas they significantly upregulated anti-angiogenic genes such as serpinF1, sprouty1, and angioarrestin. Analysis of protein expression confirmed the downregulation of FGF-2 and Tie-2 (27%±8% and 13%±1% of non-induced cells, respectively) and upregulation of the anti-angiogenic protein endostatin (226%±4%). Conditioned media collected from hAMSC enhanced viability of endothelial cells and had a stabilizing effect on endothelial network formation as shown by lactate dehydrogenase and Matrigel assay, respectively. In summary, endothelial induced hAMSC acquired some angiogenic properties but resisted undergoing a complete differentiation into mature endothelial cells by upregulation of anti-angiogenic factors. Nevertheless, they had a survival-enhancing effect on endothelial cells that might be useful in a variety of cell therapy or tissue-engineering approaches.

Immunohistochemical expression of fibroblast growth factor-2 in developing human cerebrum and epilepsy-associated malformations of cortical development

To elucidate the biological significance of fibroblast growth factor-2 (FGF-2) expression in epilepsy-associated malformations of cortical development, immunohistochemical expression of FGF-2 was investigated in the developing human cerebral mantles obtained from 30 autopsy cases of fetuses, stillborn infants and children ranging from 12 weeks gestation to 15 years old, and 70 surgically-resected corticectomy specimens from patients with medically intractable epilepsy, including: group I, 12 tubers of tuberous sclerosis; group II, 24 cases of focal cortical dysplasia (FCD) with balloon cells (BC); group III, 11 FCD without BC; group IV, 23 histologically normal-appearing neocortices from patients with Rasmussen encephalitis, cystic-gliotic encephalopathy, temporal lobe epilepsy; and group V, 14 normal-appearing neocortices adjacent to dysplastic lesions from groups I and II. FGF-2 expression was detected in a population of matrix cells and/or neuroblasts within the ventricular zone in fetuses younger than 19 weeks gestation. Nuclei of glioblasts and immature astrocytes were also positive for FGF-2 in cases older than 18 weeks gestation. FGF-2 expression was not detected in immature cortical plate neurons. Astrocytes and ependymal cells were positive for FGF-2 in the postnatal brains. Choroid plexus epithelium was strongly positive for FGF-2 in all cases examined. Among the corticectomy specimens, the cytoplasms and/or nuclei of dysmorphic neurons (DNs) and BCs in groups I and II were variably positive for FGF-2. The proportions of FGF-2 immunoreactive cells (FGF-2-IR%) was significantly higher in groups I (36.9 ± 9.6) and II (45.1 ± 7.0) than in groups III (21.0 ± 5.7), IV (14.4 ± 4.7) and V (24.3 ± 10.3), and that in group V was higher than in group IV (P<0.01). These results indicate that FGF-2 upregulation in DNs and BCs is an important feature common to groups I and II, and suggest that BCs and DNs in these groups represent disturbed gliogenesis from matrix cells and disturbed maturation of cortical neurons from migrating neuroblasts, respectively.

Notch1 mediates visfatin-induced FGF-2 up-regulation and endothelial angiogenesis

Our aims were to determine the role of Notch1 in mediating visfatin-induced angiogenesis and to explore potential target genes involved. Inhibition of Notch signalling attenuated visfatin-induced angiogenesis in vitro, ex vivo, and in vivo. Visfatin increased γ-secretase activity, Notch1 cleavage and activation, and Hes1 gene induction. Visfatin also stimulated fibroblast growth factor-2 (FGF-2) gene expression in a Notch1-dependent manner. Enforced expression of active Notch1 intracellular domain increased FGF-2 protein levels and stimulated endothelial tube formation, whereas blocking Notch1 signalling or knockdown of Notch1 by small interfering RNA suppressed visfatin-induced FGF-2 up-regulation and angiogenesis. Reporter analysis of FGF-2 promoter revealed the presence of CSL (CBF-1, suppressor of hairless, LAG-1)-binding site, and chromatin immunoprecipitation analysis demonstrated the binding of Notch1-CSL complex to this site in response to visfatin. Our data provide the first example of Notch1-dependent endothelial FGF-2 induction by visfatin and of Notch1 activation in visfatin-stimulated endothelial angiogenesis, suggesting that the signalling axis of visfatin/Notch1/angiogenic factors like FGF-2 might be a valuable target for pathological angiogenesis.

Nanoscale Tissue Scaffold Investigations to Optimize Central Nervous System Prosthetic

The introduction of scaffolding materials with appropriate biochemical cues and physical properties into damaged sites within the central nervous system can encourage endogenous or exogenous cellular re-colonization. The scaffolding material currently under investigation is a synthetic electrospun polyamide nanofibrillar matrix that has demonstrated promise in tissue engineering approaches for the repair of the injured spinal cord and is architecturally mimetic for the capillary basement membrane at the blood brain barrier. We will present quantitative investigations of the nanofibrillar matrix, which are achieved through use of a dynamic new mode of atomic force microscopy, Scanning Probe Recognition Microscopy (SPRM). SPRM uniquely allows auto-tracking along individual nanofibers, which are then compiled into a statistical representation of the nanofibrillar matrix as a whole. Complementary transmission electron microscopy (TEM) and nuclear magnetic resonance (NMR) investigations are performed to assess nanofiber internal structures that contribute to elasticity, and growth factor binding site information, respectively. Results of investigations of unmodified nanofibers and nanofibers covalently modified with fibroblast growth factor-2 (FGF-2), a prevailing cytokine involved in regulation of the growth of astrocytes, neurons, and other neural cells, will be presented.Astrocytes are neural cells that can be considered to be the cellular bridge between the capillary basement membrane and neurons. They are therefore directly responsive to the biochemical cues and physical properties of the native or prosthetic basement membrane. We will present results achieved through SPRM, immunocytochemistry, and Western blot techniques that indicate that there are significant differences in the astrocyte response to 2D planar substrates versus 3D nanofibrillar substrates versus 3D nanofibrillar substrates that are covalently modified with FGF-2, mimicking the sequestration of growth factors on the basement membrane. Differences in astrocyte physiology, substrate probing through lamellipodia and filopodia extension and FGF-2 up-regulation will be discussed.

Fibroblast growth factor 2: A new key player in osteoarthritis

Vincent, Saklatvala, and colleagues have taken an interesting approach over the last 5 years by defining molecules that may be of importance in osteoarthritis (OA) through the investigation of proteins that are modulated following damage to articular cartilage. This approach has now paid off in a major way with the discovery that fibroblast growth factor 2 (FGF-2) is a key chondroprotective factor in an OA model, as reported by Chia et al (1) in this issue of Arthritis & Rheumatism. The authors made their original observations regarding FGF-2 through the investigation of ERK activation following explantation or explantation and subsequent cutting of cartilage (2). They showed that as rapidly as 30 minutes after damage, FGF-2 was liberated into the culture medium of cartilage, from which it could be purified. Later studies revealed that FGF-2 is found in a pericellular perlecan-bound pool in normal articular cartilage. Some FGF-2 was hypothesized to be liberated from this pool following mechanical loading, allowing it to stimulate ERK signaling as well as induction of certain matrix metalloproteinase (MMP) genes and tissue inhibitor of metalloproteinases 1 (TIMP-1) (3,4). Chia et al have now pursued these observations in an in vivo model of OA. Suppression of aggrecan degradation is regarded as a major goal in the prevention of cartilage destruction and loss of function in OA (for review, see ref. 5). Elegant studies in mouse models of arthritis have revealed that ADAMTS-5 is the key enzyme in aggrecan breakdown in this context (6,7). Moreover, biochemical analysis has revealed that human ADAMTS-5 has 1,000fold greater activity on aggrecan than does ADAMTS-4 (8). Studies of the regulation of aggrecanases have shown that the cytokine interleukin-1 (IL-1) induces ADAMTS-5 to a lesser degree than ADAMTS-4, but given the disparity in aggrecanase activity, this may not reflect a lesser importance for ADAMTS-5 (5). Although metalloproteinase expression levels in end-stage OA showed that ADAMTS-5 was among the proteinases that are repressed at this time point (9), recent genome-wide microarray studies of a surgically induced OA in the rat have revealed that Adamts5 is upregulated 4 weeks after surgery (10). These data suggest that ADAMTS-5 is likely to be important in early aggrecan cleavage during the development of OA, but may be repressed, perhaps through a feedback mechanism, during late stages of OA. Following their previous observations regarding FGF-2 up-regulation in damaged cartilage, Chia et al explored the effect of Fgf2 gene deletion on cartilage structure and on the development of OA-like characteristics in a surgically induced model of OA. They showed first that Fgf2 mice had increased development of OA with age as compared with wild-type (WT) mice, with marked effects at ages 6 and 9 months. At age 3 months, no differences were observed between genotypes in terms of cartilage breakdown or expression levels of several key genes, including aggrecan, type II collagen, and Adamts5. The authors did not examine the levels of these genes at ages 6 or 9 months, when one might expect to see an up-regulation of Adamts5 expression and function. Surgical destabilization of the knee was performed at age 10–12 weeks in both WT and Fgf2 mice, and the authors demonstrated that Fgf2 mice developed a more severe OA phenotype that was detectable 2, 4, and 8 weeks after surgery. Both cartilage thickness and proteoglycan content (estimated by Safranin O staining) were assessed. Of interest is the fact that Jelena Gavrilovic, PhD: University of East Anglia, Norwich, UK. Address correspondence and reprint requests to Jelena Gavrilovic, PhD, Cellular Protease Group, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK. E-mail: J.Gavrilovic@uea.ac.uk. Submitted for publication March 6, 2009; accepted in revised form April 7, 2009. Arthritis & Rheumatism

FGF2 transcript levels are positively correlated with EGF and IGF-1 in the malignant endometrium

Background. Epidermal and insulin-like growth factors (EGF, IGFs) act as mitogens promoting endothelial cell proliferation and differentiation. Accumulating evidence for interactions between EGF and IGF signaling pathways has been reported. Fibroblast Growth Factor-2 (FGF2) is also mitogenic for various cell types and is associated with regulation of tumor angiogenesis and metastasis. However EGF, IGF-1 and FGF2 transcript levels have been scarcely investigated in endometrial carcinoma. Methods. In the present study, we evaluated the mRNA expression pattern of EGF, IGF-1 and FGF2 by using Comparative Quantitative real-time RT-PCR assay in 30 endometrial cancer specimens and an equal number of adjacent normal tissues. Results. Both overexpression and down-regulation of EGF, IGF-1 and FGF2 was demonstrated in endometrial cancer compared to the adjacent normal specimens; however the main features of cancer were IGF-1 and EGF down-regulation and FGF2 up-regulation. Different co-expression patterns of all three factors were displayed in normal and malignant endometrium. Interestingly, FGF2 mRNA was positively correlated with EGF and IGF-1 transcript levels in endometrial cancer ( P = 0.024 and P = 0.006, respectively), while no co-expression was observed in the adjacent normal specimens. Furthermore, endometrial tissue-pair analysis revealed a significant positive correlation between EGF and IGF-1 ( P = 0.010), supporting the hypothesis of a cross-talk between IGF- and EGF-mediated signaling pathways in endometrial cancer. EGF transcript levels were marginally higher in endometrioid than non-endometrioid tumors ( P = 0.050), and in grade I compared to grade II tumors ( P = 0.053). Conclusions. Up-regulation as well as down-regulation of EGF, IGF-1 and FGF2 transcript levels is observed in endometrial cancer; however IGF-1 and EGF down-regulation and FGF2 up-regulation seem to comprise the main features of endometrial carcinogenesis. The disruption of their mRNA co-expression pattern observed supports the hypothesis of a cross-talk between IGF- and EGF-mediated signaling pathways in promoting endothelial cell proliferation and differentiation in endometrial cancer.

Changes in fibroblast growth factor 2 and its receptors in bovine follicles before and after GnRH application and after ovulation

The aim of this study was to evaluate the expression pattern of fibroblast growth factor 2 (FGF2), its receptor variants (FGFR1IIIc, FGFR2IIIc) and nucleolin in time-defined follicle classes before and after GnRH application and after ovulation in the cow. Ovaries containing preovulatory follicles or new corpora lutea (CL) were collected at approximately 0, 4, 10, 20 and 25 h (follicles) and 60 h (new CL) relative to injection of GnRH to induce an LH surge (n = 5 animals per group). The expressions of FGF2 and FGFR1IIIc mRNA were significantly up-regulated only in the follicle group 4 h after GnRH (during the LH surge) with a significant down-regulation immediately afterwards. Western blot analyses showed two protein bands with at 22 and 18 kDa with apparent up-regulation beginning with the LH surge (4 h) and maximum levels 20 h after GnRH. FGF2 protein in follicles collected at 0 h (before LH surge) was localised in theca tissue (endothelial and pericytes of blood vessels) but not in granulosa cells (GCs). The FGF2 staining (by immunohistochemistry) pattern changed dramatically after the LH surge for a short period (about 2 days) and FGF2 protein was localised dominantly in the nucleus of many GCs, while most capillary endothelial cells were FGF2 immunonegative. In conclusion, the novel observation of FGF2 up-regulation and the distinct change in FGF2 localisation from theca (cytoplasm of endothelial cells) to the nucleus of GCs after the LH surge may be important for survival of GCs or for the transition of the GCs to luteal cells.

Dynamic regulation of fibroblast growth factor 2 (FGF‐2) gene expression in the rat brain following single and repeated cocaine administration

Administration of drugs of abuse can produce long-lasting effects on brain function, which involve modifications at neurotransmitter level as well as changes in proteins important for structural alterations of selected brain regions. The contribution of trophic factors in these events has so far been underestimated. Here, we demonstrate that a single cocaine injection selectively up-regulated fibroblast growth factor 2 (FGF-2) mRNA levels in the striatum and prefrontal cortex within 2 h, an effect that vanished by 24 h. However, prolonged exposure (5 or 14 days) to cocaine treatment produced an enduring elevation of FGF-2 mRNA levels that was evident 72 h after the last injection in the prefrontal cortex and could even persist for 14 days in the striatum, raising the possibility that cocaine treatment primes the brain, resulting in longer-lasting FGF-2 up-regulation in regions that are highly innervated by dopaminergic projections. The expression of FGF-2 was also significantly increased in the midbrain following acute or 5-day injection, suggesting that modulation of FGF-2 biosynthesis in dopamine-producing cells occurs only during early stages of cocaine exposure. Our results point to important mechanistic conclusions as to how cocaine alters FGF-2 expression. Whereas cocaine-induced changes in FGF-2 gene expression following a single injection could be ascribed to increased release of transmitters (mainly dopamine), enhanced FGF-2 gene expression following repeated administration identifies the trophic factor as part of the adaptive changes set in motion by cocaine.

FGF-2 Up-regulation and Proliferation of Neural Progenitors in the Regenerating Amphibian Spinal Cord in Vivo

Regeneration of the spinal cord occurs spontaneously in adult urodele amphibians. The key cells in this regenerative process appear to be the ependymal cells that following injury migrate and proliferate to form the ependymal tube from which the spinal cord regenerates. Very little is known about the signal(s) that initiates and maintains the proliferative response of these cells. Fibroblast growth factor 2 (FGF-2) has been shown to play a role in maintaining neural progenitor cell cycling in vitro and may be important for neuronal survival and axonal growth after injury. We have investigated its role in regeneration of the spinal cord in vivo following tail amputation in the adult salamander, Pleurodeles waltl. We show that only the low-molecular-weight form of FGF-2 is found in Pleurodeles and that in the normal cord it is expressed in a subset of neurons, but is hardly detectable in ependymal cells. Tail amputation results in induction of FGF-2 in the ependymal cells of the regenerating structure, and later in regeneration FGF-2 is up-regulated in some newborn neurons. FGF-2 pattern of expression in the ependymal tube parallels that of proliferation. Furthermore, exogenous FGF-2 significantly increases ependymal cell proliferation in vivo. Overall our results strongly support the view that one important role of FGF-2 during spinal cord regeneration in Pleurodeles is to induce proliferation of neural progenitor cells.