Presence Of Fibroblast Growth Factor Receptor Research Articles

Abstract A039: FGF/PTX3 crosstalk in bladder cancer: novel prognostic and therapeutic implications

Abstract Bladder cancer is one of the most common cancers in the world. Although most of urothelial carcinomas (UCs) are low-grade papillary tumors, their propensity to recur and to progress to become invasive with a poor survival rate represents a major challenge. Different members of the Fibroblast growth factor (FGF) family are expressed by human bladder cancer cells, and aberrant expression of FGF receptors (FGFRs) is a typical feature of bladder cancer compared to normal urothelium. High expression levels of FGFR1 are associated with poor survival and FGFR3 is frequently dysregulated in UC. Thus, the FGF/FGFR system may represent a promising therapeutic target in invasive and noninvasive bladder cancer. Long-pentraxin 3 (PTX3) acts as a natural FGF trap by binding FGFs and hampering their biologic activity in various tumor models. Preliminary observations have shown that low-grade UCs express PTX3 while high-grade/invasive UCs lose PTX3 expression. Accordingly, bladder cancer cell lines share an overall presence of FGFRs and FGFs but express different levels of PTX3 in vitro and in vivo. Of note, high-grade/invasive cells express very low or undetectable levels of PTX3, whereas low-grade, papilloma-like cells express high levels of PTX3. Indeed, invasive bladder cancer cell xenografts grow faster in nude mice and express much lower levels of PTX3 than low grade-derived lesions, thus confirming an inverse correlation between UC grade and PTX3 expression. This hypothesis is reinforced by a preliminary case study performed on a small cohort of biopsies from UC patients confirming that the presence of PTX3 is a common feature of low-grade samples while PTX3 is poorly expressed or absent in aggressive/invasive cases. These data point to PTX3 as a natural FGF trap that could play a role in modulating bladder cancer progression and invasiveness and indicate that inhibition of the FGF/FGFR system by natural and synthetic FGF traps may represent a promising target for the therapy of UCs. Citation Format: Sara Matarazzo, Federica Maccarinelli, Gaia Cristina Ghedini, Laura Melocchi, Mattia Bugatti, William Vermi, Marco Presta, Roberto Ronca. FGF/PTX3 crosstalk in bladder cancer: novel prognostic and therapeutic implications [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A039.

117 FIBROBLAST GROWTH FACTOR RECEPTOR-1c, -2c, -3c, and -4 mRNA ABUNDANCE IN GRANULOSA CELLS DURING FOLLICULAR GROWTH IN CATTLE

Fibroblast growth factors (FGF) regulate folliculogenesis of several species, including cattle. The cellular responses to a particular FGF are influenced by the diversity of high affinity fibroblast growth factor receptors (FGFR). There are 4 distinct genes encoding FGFR in vertebrates and the occurrence of mRNA splicing in the immunoglobulin-like domain III generates a diversity of sequences, and results in various isoforms of FGFR1, FGFR2, and FGFR3 (but not of FGFR4). Because FGFR have different ligand specificities, the presence of FGFR in bovine antral follicles is of fundamental importance for the FGF to exert their effects in the ovary. Hence, the objective of this study was to determine if FGFR1c, FGFR2c, FGFR3c, and FGFR4 mRNA abundance in granulosa cells (GC) change according to follicular size, steroidogenic status, and days post-ovulation during growth of first-wave dominant follicles in cattle. Oestrous cycles of non-lactating dairy cattle were synchronized and ovaries were collected on either Day 3–4 (n = 8) or Day 5–6 (n = 8) post-ovulation (as assessed by rectal ultrasonography). Follicular fluid (FFL) was aspirated from small (1–5 mm), medium (5.1–8 mm), or large (8.1–18 mm) follicles for measurement of oestradiol (E2) and progesterone (P4) levels by radioimmunoassay, and GC were collected for mRNA extraction. Relative quantity of target gene mRNA was expressed as 2−ΔΔCt using the comparative threshold cycle (Ct) method. Data were transformed to natural log (x + 1), to correct for heterogeneity of variance, and analysed via factorial ANOVA with the general linear model procedure of SAS and are reported as least squares means ± s.e.M. Follicle group (based on steroidogenic status and size of follicles), but not days post-ovulation or their interaction, significantly affected FGFR1c, FGFR2c, and FGFR3c mRNA abundance, whereas FGFR4 mRNA abundance was not affected by follicle group or days post-ovulation. FGFR1c mRNA abundance was greater (P < 0.01) in large (44.8 ± 11.3; n = 29), medium (63.8 ± 7.6; n = 64), and small (44.6 ± 11.2; n = 29) E2-inactive (FFL E2/P4 ratio < 1) than in large E2-active (FFL E2/P4 ratio > 1) follicles (10.5 ± 15.5; n = 16) and greater (P < 0.05) in medium E2-inactive than in large and small E2-inactive follicles. FGFR2c mRNA abundance was greater (P < 0.01) in large (423.9 ± 131.9), medium (585.8 ± 97.0), and small (273.6 ± 143.2) E2-inactive than in large E2-active (56.2 ± 195.6) follicles. The FGFR3c mRNA abundance was greater (P < 0.05) in large (143.4 ± 40.2) and medium (160.2 ± 29.3) E2-inactive than in large E2-active (43.2 ± 58.6) follicles and tended to be greater (P = 0.06) in small E2-inactive (101.9 ± 42.9) than in large E2-active follicles. Taken together, the findings that FGFR1c, FGFR2c, and FGFR3c mRNA abundance is lower in GC of E2-active follicles during growth of the first dominant follicle support an anti-differentiation role for these FGFR as well as support the idea that some FGF may regulate the selection of dominant follicles in cattle.

Expression of Fibroblast Growth Factor Receptors 1–4 in Human Chronic Tympanic Membrane Perforation

Objective: To locate fibroblast growth factor receptor (FGFRs) 1–4 in human chronic tympanic membrane (TM) perforation. Methods: A sample of human chronic TM perforation was harvested during myringoplasty. The sample was immediately fixed in 4% paraformaldehyde and embedded in OCT compound. Immunohistochemistry was performed with FGFR 1–4 polyclonal antibodies. Results: FGFRs 1–4 were strongly and weakly expressed in the epidermal and mucosal layer of the TM perforation, respectively. Conclusions: As it is impossible to perform quantitative analysis based on the fluorescence intensity of each immunoreactivity, the presence of FGFRs 1–4 in the human chronic TM perforation is shown. The expressions of FGFRs 1–4 indicated that the clinical use of bFGF agent is useful for myringoplasty.

Pertussis toxin-sensitive G-proteins inhibit fibroblast growth factor-induced signaling in pancreatic acini.

Signal transduction of fibroblast growth factor (FGF) receptors is known to involve tyrosine phosphorylation of several substrates, including Grb2, phospholipase C-gamma, and phosphatidylinositol 3-kinase, whereas the role of G-proteins in FGF receptor signaling is controversial. In the present study we investigated the role of G-proteins in FGF receptor signaling in rat pancreatic acini. Immunological analysis revealed the presence of FGF receptor and phospholipase C-gamma1 in rat pancreatic acini. Both basic fibroblast growth factor (FGF-2) and guanosine 5'-(gamma-O-thio)triphosphate (GTPgammaS) caused an increase in inositol 1,4,5-trisphosphate (1,4,5-IP3) production and amylase release. Combined stimulation of the acini with GTPgammaS and FGF-2 led to a decrease of these responses as compared to the effect of the single substances. When pancreatic acini were preincubated with FGF-2 (1 nM) or vehicle (water) ADP-ribosylation of the alpha-subunit of Gi-type G-proteins by pertussis toxin was reduced in membranes prepared from FGF-2 pretreated acini as compared to control acini, suggesting functional interaction of FGF receptors with Gi-proteins. Pretreatment of acini with pertussis toxin which inhibits Gi-type G-proteins abolished the inhibitory effect of GTPgammaS on FGF-induced 1,4,5-IP3 production and amylase release, whereas the stimulatory effects of FGF-2 and GTPgammaS on these parameters remained unchanged. In conclusion, these results show communication of FGF receptors and Gi-type G-proteins and that Gi-type G-proteins exert an inhibitory influence on FGF-induced activation of phosphoinositide-specific phospholipase C in pancreatic acinar cells.