Role of FGF Receptors and Their Pathways in Adrenocortical Tumors and Possible Therapeutic Implications.

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy and treatment of advanced disease is challenging. Clinical trials with multi-tyrosine kinase inhibitors in the past have yielded disappointing results. Here, we investigated fibroblast growth factor (FGF) receptors and their pathways in adrenocortical tumors as potential treatment targets. We performed real-time RT-PCR of 93 FGF pathway related genes in a cohort of 39 fresh frozen benign and malignant adrenocortical, 9 non-adrenal tissues and 4 cell lines. The expression of FGF receptors was validated in 166 formalin-fixed paraffin embedded (FFPE) tissues using RNA in situ hybridization (RNAscope) and correlated with clinical data. In malignant compared to benign adrenal tumors, we found significant differences in the expression of 16/94 FGF receptor pathway related genes. Genes involved in tissue differentiation and metastatic spread through epithelial to mesechymal transition were most strongly altered. The therapeutically targetable FGF receptors 1 and 4 were upregulated 4.6- and 6-fold, respectively, in malignant compared to benign adrenocortical tumors, which was confirmed by RNAscope in FFPE samples. High expression of FGFR1 and 4 was significantly associated with worse patient prognosis in univariate analysis. After multivariate adjustment for the known prognostic factors Ki-67 and ENSAT tumor stage, FGFR1 remained significantly associated with recurrence-free survival (HR=6.10, 95%CI: 1.78 - 20.86, p=0.004) and FGFR4 with overall survival (HR=3.23, 95%CI: 1.52 - 6.88, p=0.002). Collectively, our study supports a role of FGF pathways in malignant adrenocortical tumors. Quantification of FGF receptors may enable a stratification of ACC for the use of FGFR inhibitors in future clinical trials.

Expression and localization of FGFR1, FGFR2 and CTGF during normal human lung development.

Aim of our study was to provide insight into the temporal and spatial expression of FGFR1, FGFR2 and CTGF during normal human lung development which may have an important impact on understanding occurrence of developmental lung anomalies. Morphological parameters were analysed using double immunofluorescence on human embryonal (6th and 7th developmental week-dw) and foetal (8th, 9th and 16th developmental week) human lung samples. FGFR1 and FGFR2 was positive during all the dw in both the epithelium and mesenchyme. The highest number of FGFR1 positive cells was observed during the 6th dw (112/mm2) and 9th dw (87/mm2) in the epithelium compared to the 7th, 8th and 16th dw (Kruskal-Wallis test, p < 0.001, p < 0.0001). The highest number of FGFR1 positive cells in the mesenchyme was observed during the 8th dw (19/mm2) and 16th dw (13/mm2) compared to the 6th, 7th, and 9th dw (Kruskal-Wallis test, p < 0.001, p < 0.0001). The number of FGFR1 positive cells in the epithelium was higher for FGFR2 compared to number of positive cells (Mann-Whitney test, p < 0.0001). FGFR2 showed the highest number in the epithelium during the 7th dw (111/mm2) and 9th dw (87/mm2) compared to 6th, 8th and 16th dw (Kruskal-Wallis test, p < 0.001, p < 0.0001, p < 0.01 respectively). The highest number of FGFR2 positive cells in the mesenchyme was observed during the 9th dw (26/mm2), compared to the 6th, 7th,8th and 16th dw (Kruskal-Wallis test, p < 0.0001), while the number of FGFR2 positive cells in the epithelium was significantly higher than in the mesenchyme (Mann-Whitney test, p < 0.0001). CTGF was negative in both epithelium and mesenchyme during all except the 16th dw in the mesenchyme where it co-localized with FGFR2. FGFR1 and FGFR2 might be essential for epithelial-mesenchymal interactions that determine epithelial branching and mesenchymal growth during early lung development. Sudden increase in FGF1 in the epithelium and FGF2 in the mesenchyme in the foetus at 9th dw could be associated with the onset of foetal breathing movements. CTGF first appear during the foetal lung development.

circITGA7 Functions as an Oncogene by Sponging miR-198 and Upregulating FGFR1 Expression in Thyroid Cancer.

BACKGROUND: Emerging evidence has indicated that circular RNAs (circRNAs), recognized as functional noncoding transcripts in eukaryotic cells, may be involved in regulating many physiological or pathological processes. However, the regulation and function of circular RNA circITGA7 in thyroid cancer (TC) remains unknown. METHODS: In this study, we found that circITGA7 is upregulated in TC cell lines. We then performed functional analyses in the cell lines to support clinical findings. Mechanistically, we demonstrated that circITGA7 can directly bind to miR-198 and reduce the inhibition effect of miR-198 on target FGFR1 expression. RESULTS: We reported an upregulation of circITGA7 in patients with TC. Silencing of circITGA7 inhibits metastasis and proliferation of TC cell lines in vitro. In addition, in the TC cell lines, the knockdown of circITGA7 or overexpression of miR-198 significantly suppressed FGFR1 levels. Mechanistically, we found that circITGA7 acts as miR-198 competitive endogenous RNA (ceRNA) to regulate FGFR1 expression. CONCLUSIONS: In summary, circRNA circITGA7 may play a regulatory role in TC and may be a potential marker for TC diagnosis or progression.

Critical individual roles of the BCR and FGFR1 kinase domains in BCR-FGFR1-driven stem cell leukemia/lymphoma syndrome.

Constitutive activation of FGFR1, as a result of diverse chromosome translocations, is the hallmark of stem cell leukemia/lymphoma syndrome. The BCR-FGFR1 variant is unique in that the BCR component contributes a serine-threonine kinase (STK) to the N-terminal end of the chimeric FGFR1 kinase. We have deleted the STK domain and mutated the critical Y177 residue and demonstrate that the transforming activity of these mutated genes is reduced compared to the BCR-FGFR1 parental kinase. In addition, we demonstrate that deletion of the FGFR1 tyrosine kinase domain abrogates transforming ability, which is not compensated for by BCR STK activity. Unbiased screening for proteins that are inactivated as a result of loss of the BCR STK identified activated S6 kinase and SHP2 kinase. Genetic and pharmacological inhibition of SHP2 function in SCLL cells expressing BCR-FGFR1 in vitro leads to reduced viability and increased apoptosis. In vivo treatment of SCLL in mice with SHP099 leads to suppression of leukemogenesis, supporting an important role for SHP2 in FGFR1-driven leukemogenesis. In combination with the BGJ398 FGFR1 inhibitor, cell viability in vitro is further suppressed and acts synergistically with SHP099 in vivo suggesting a potential combined targeted therapy option in this subtype of SCLL disease.

Polarizing receptor activation dissociates fibroblast growth factor 2 mediated inhibition of myelination from its neuroprotective potential.

Fibroblast growth factor (FGF) signaling contributes to failure of remyelination in multiple sclerosis, but targeting this therapeutically is complicated by its functional pleiotropy. We now identify FGF2 as a factor up-regulated by astrocytes in active inflammatory lesions that disrupts myelination via FGF receptor 2 (FGFR2) mediated activation of Wingless (Wnt) signaling; pharmacological inhibition of Wnt being sufficient to abrogate inhibition of myelination by FGF2 in tissue culture. Using a novel FGFR1-selective agonist (F2 V2) generated by deleting the N-terminal 26 amino acids of FGF2 we demonstrate polarizing signal transduction to favor FGFR1 abrogates FGF mediated inhibition of myelination but retains its ability to induce expression of pro-myelinating and immunomodulatory factors that include Cd93, Lif, Il11, Hbegf, Cxcl1 and Timp1. Our data provide new insights into the mechanistic basis of remyelination failure in MS and identify selective activation of FGFR1 as a novel strategy to induce a neuroprotective signaling environment in multiple sclerosis and other neurological diseases.

DNA methyltransferase 1-mediated CpG methylation of the miR-150-5p promoter contributes to fibroblast growth factor receptor 1-driven leukemogenesis.

MicroRNA-150-5p (miR-150-5p) plays a complex role in normal early hematopoietic development and is also implicated in the development of various different leukemias. We have reported previously that, in myeloid and lymphoid malignancies associated with dysregulated fibroblast growth factor receptor 1 (FGFR1) activities, miR-150-5p is down-regulated compared with healthy cells. Here, using murine cells, we found that this down-regulation is accompanied by CpG methylation of the miR-150-5p promoter region. Of note, analysis of human acute lymphoblastic leukemia (ALL) cohorts also revealed an inverse relationship between miR-150-5p expression and disease progression. We also found that the DNA methyltransferase 1 (DNMT1) enzyme is highly up-regulated in FGFR1-driven leukemias and lymphomas and that FGFR1 inhibition reduces DNMT1 expression. DNMT1 knockdown in stem cell leukemia/lymphoma (SCLL) cells increased miR-150-5p levels and reduced levels of the MYB proto-oncogene transcription factor, a key regulator of leukemogenesis. FGFR1 directly activates the MYC proto-oncogene basic helix-loop-helix transcription factor, which, as we show here, binds and activates the DNMT1 promoter. MYC knockdown decreased DNMT1 expression, which, in turn, increased miR-150-5p expression. One of the known targets of miR-150-5p is MYB, and treatment of leukemic cells with the MYB inhibitor mebendazole dose-dependently increased apoptosis and reduced cell viability. Moreover, mebendazole treatment of murine xenografts models of FGFR1-driven leukemias enhanced survival. These findings provide evidence that MYC activates MYB by up-regulating DNMT1, which silences miR-150-5p and promotes SCLL progression. We propose that inclusion of mebendazole in a combination therapy with FGFR1 inhibitors may be a valuable option to manage SCLL.

Inhibition of FGF Receptor-1 Suppresses Alcohol Consumption: Role of PI3 Kinase Signaling in Dorsomedial Striatum.

Excessive alcohol intake leads to mesostriatal neuroadaptations, and to addiction phenotypes. We recently found in rodents that alcohol increases fibroblast growth factor 2 (FGF2) expression in the dorsomedial striatum (DMS), which promotes alcohol consumption. Here, we show that systemic or intra-DMS blockade of the FGF2 receptor, FGF receptor-1 (FGFR1), suppresses alcohol consumption, and that the effects of FGF2-FGFR1 on alcohol drinking are mediated via the phosphoinositide 3 kinase (PI3K) signaling pathway. Specifically, we found that sub-chronic alcohol treatment (7 d × 2.5 g/kg, i.p.) increased Fgfr1 mRNA expression in the dorsal hippocampus and dorsal striatum. However, prolonged and excessive voluntary alcohol consumption in a two-bottle choice procedure increased Fgfr1 expression selectively in DMS. Importantly, systemic administration of the FGFR1 inhibitor PD173074 to mice, as well as its infusion into the DMS of rats, decreased alcohol consumption and preference, with no effects on natural reward consumption. Finally, inhibition of the PI3K, but not of the mitogen-activated protein kinase (MAPK) signaling pathway, blocked the effects of FGF2 on alcohol intake and preference. Our results suggest that activation of FGFR1 by FGF2 in the DMS leads to activation of the PI3K signaling pathway, which promotes excessive alcohol consumption, and that inhibition of FGFR1 may provide a novel therapeutic target for alcohol use disorder.SIGNIFICANCE STATEMENT Long-term alcohol consumption causes neuroadaptations in the mesostriatal reward system, leading to addiction-related behaviors. We recently showed that alcohol upregulates the expression of fibroblast growth factor 2 (FGF2) in dorsomedial striatum (DMS) or rats and mice, and in turn, FGF2 increases alcohol consumption. Here, we show that long-term alcohol intake also increases the expression of the FGF2 receptor, FGFR1 in the DMS. Importantly, inhibition of FGFR1 activity by a selective receptor antagonist reduces alcohol drinking, when given systemically or directly into the DMS. We further show that the effects of FGF2-FGFR1 on alcohol drinking are mediated via activation of the PI3K intracellular signaling pathway, providing an insight on the mechanism for this effect.

Immunohistochemical expression pattern of RIP5, FGFR1, FGFR2 and HIP2 in the normal human kidney development.

AIM: Present study analyses the co-localisation of RIP5 with FGFR1, FGFR2 and HIP2 in the developing kidney, as RIP5 is a major determinant of urinary tract development, downstream of FGF-signaling. METHODS: Paraffin embedded human kidney tissues of 16 conceptuses between the 6th-22th developmental week were analysed using double-immunofluorescence method with RIP5/FGFR1/FGFR2 and HIP2 markers. Quantification of positive cells were performed using Kruskal-Wallis test. RESULTS: In the 6th week of kidney development RIP5 (89.6%) and HIP2 (39.6%) are strongly expressed in the metanephric mesenchyme. FGFR1 shows moderate/strong expression in the developing nephrons (87.3%) and collecting ducts (70.5%) (p < 0.05). RIP5/FGFR1 co-localized at the marginal zone and the ureteric bud with predominant FGFR1 expression. FGFR2 (26.1%) shows similar expression pattern as FGFR1 (70.5%) in the same kidney structures. RIP5/FGFR2 co-localized at the marginal zone and the collecting ducts (predominant expression of FGFR2). HIP2 is strongly expressed in collecting ducts (96.7%), and co-localized with RIP5. In 10th week, RIP5 expression decrease (74.2%), while the pattern of expression of RIP5 and FGFR1 in collecting ducts (33.4% and 91.9%) and developing nephrons (21.9% and 32.4%) (p < 0.05) is similar to that in the 6th developmental week. Ureter is moderately expressing RIP5 while FGFR1 is strongly expressed in the ureteric wall. FGFR2 is strongly expressed in the collecting ducts (84.3%) and ureter. HIP2 have 81.1% positive cells in the collecting duct. RIP5/FGFR1 co-localize in collecting ducts and Henley's loop. CONCLUSIONS: The expression pattern of RIP5, FGFR1, FGFR2 and HIP2 in the human kidney development might indicate their important roles in metanephric development and ureteric muscle layer differentiation through FGF signaling pathways.

Constitutive activation of Notch2 signalling confers chemoresistance to neural stem cells via transactivation of fibroblast growth factor receptor-1.

Notch signalling regulates neural stem cell (NSC) proliferation, differentiation and survival for the correct development and functioning of the central nervous system. Overactive Notch2 signalling has been associated with poor prognosis of aggressive brain tumours, such as glioblastoma multiforme (GBM). We recently reported that constitutive expression of the Notch2 intracellular domain (N2ICD) enhances proliferation and gliogenesis in NSCs. Here, we investigated the mechanism by which Notch2 promotes resistance to apoptosis of NSCs to cytotoxic insults. We performed ex vivo studies using NSC cultures from transgenic mice constitutively expressing N2ICD. These NSCs expressed increased levels of pro-survival factors and lack an apoptotic response to the topoisomerase inhibitor etoposide, not showing neither mitochondrial damage nor caspase activation. Interestingly, Notch2 signalling also regulated chemoresistance of human GBM cells to etoposide. We also identified a signalling crosstalk with FGF signalling pathway involved in this resistance to apoptosis of NSCs. Aberrant Notch2 expression enhances fibroblast growth factor receptor-1 (FGFR1) activity to specifically target the AKT-GSK3 signalling pathway to block apoptosis. These results have implications for understanding molecular changes involved in both tumorigenesis and therapy resistance.

FGFR1 Cooperates with EGFR in Lung Cancer Oncogenesis, and Their Combined Inhibition Shows Improved Efficacy.

INTRODUCTION: There is substantial evidence for the oncogenic effects of fibroblast growth factor receptor 1 (FGFR1) in many types of cancer, including lung cancer, but the role of this receptor has not been addressed specifically in lung adenocarcinoma. METHODS: We performed FGFR1 and EGFR overexpression and co-overexpression assays in adenocarcinoma and in inmortalized lung cell lines, and we also carried out surrogate and interaction assays. We performed monotherapy and combination EGFR/FGFR inhibitor sensitivity assays in vitro and in vivo in cell line- and patient-derived xenografts. We determined FGFR1 mRNA expression in a cohort of patients with anti-EGFR therapy-treated adenocarcinoma. RESULTS: We have reported a cooperative interaction between FGFR1 and EGFR in this context, resulting in increased EGFR activation and oncogenic signaling. We have provided in vitro and in vivo evidence indicating that FGFR1 expression increases tumorigenicity in cells with high EGFR activation in EGFR-mutated and EGFR wild-type models. At the clinical level, we have shown that high FGFR1 expression levels predict higher resistance to erlotinib or gefitinib in a cohort of patients with tyrosine kinase inhibitor-treated EGFR-mutated and EGFR wild-type lung adenocarcinoma. Dual EGFR and FGFR inhibition in FGFR1-overexpressing, EGFR-activated models shows synergistic effects on tumor growth in vitro and in cell line- and patient-derived xenografts, suggesting that patients with tumors bearing these characteristics may benefit from combined EGFR/FGFR inhibition. CONCLUSION: These results support the extended the use of EGFR inhibitors beyond monotherapy in the EGFR-mutated adenocarcinoma setting in combination with FGFR inhibitors for selected patients with increased FGFR1 overexpression and EGFR activation.

VEGF-A/VEGFR-2 and FGF-2/FGFR-1 but not PDGF-BB/PDGFR-ß play important roles in promoting immature and inflammatory intraplaque angiogenesis.

Various angiogenic factors have been shown to play important roles in intraplaque angiogenesis, while little is known about the dynamic expression change and interplay between various angiogenic factors and intraplaque angiogenesis under high cholesterol conditions. New Zealand rabbits underwent balloon injury of the abdominal artery and then were assigned to a control group (n = 15, normal chow) or high cholesterol group (n = 25, 1% high cholesterol diet). At weeks 4, 6, 8, 10, and 12 after acclimation, rabbits (high cholesterol group, n = 5; control group, n = 3) were euthanized. No lesions were observed in the control group. From week 4 to week 12, the expression of vascular endothelial growth factor A (VEGF-A), VEGF receptor 2 (VEGFR-2), fibroblast growth factor 2 (FGF-2), FGF receptor 1 (FGFR-1), platelet-derived growth factor-BB (PDGF-BB), and tumor necrosis factor alpha (TNF-α), the vulnerability index (VI) and the microvessel density (MVD) were significantly elevated in the high cholesterol group; however, PDGF receptor ß (PDGFR-ß) expression showed little change. Analysis by double-label immunofluorescence (CD31 and Ng2) and FITC-dextran indicated that the neovessels within the plaque were leaky due to a lack of pericytes. As indicated by Pearson's correlation analysis, there was a highly positive correlation between the VI, MVD, macrophage content, and TNF-α level, and the levels of VEGF-A/VEGFR-2 and FGF-2/FGFR-1. However, no correlations were observed between PDGFR-ß levels and the VI or MVD. High expression of VEGF-A/VEGFR-2 and FGF-2/FGFR-1 but not of PDGF-BB/PDGFR-ß may contribute to immature and inflammatory intraplaque angiogenesis and plaque instability in a rabbit model of atherosclerosis.

Effects of FGFR1 Gene Polymorphisms on the Risk of Breast Cancer and FGFR1 Protein Expression.

BACKGROUND/AIMS: Fibroblast growth factor receptor 1 (FGFR1) is widely considered to play an important role in mammary carcinogenesis. Some common variants in FGFR1 might be associated with its expression, and further affect breast cancer risk. The aim of this study was to investigate effects of single-nucleotide polymorphisms (SNPs) in FGFR1 on breast cancer susceptibility and FGFR1 protein expression. METHODS: SNPs rs17182023, rs17175624 and rs10958704 in FGFR1 were genotyped in 747 breast cancer cases and 716 healthy controls by SNaPshot method. The associations between SNPs and breast cancer were examined by logistic regression. Immunohistochemistry(IHC) was used to detect FGFR1 protein expression, and the association of FGFR1 polymorphisms with its protein expression was analyzed by Pearson's chi-square test. Additionally, Cox regression and Kaplan-Meier analysis was used to evaluate the association between FGFR1 protein expression and breast cancer prognosis. RESULTS: The minor allele of rs17182023 in FGFR1 was significantly associated with reduced breast cancer risk, with an odds ratio of 0.800 (95%CI = 0.684-0.935). No significant associations were detected between other SNPs and breast cancer. Moreover, rs17182023 was correlated to FGFR1 protein expression (P = 0.006), and patients with high FGFR1 protein expression tended to have poor outcomes. CONCLUSIONS: SNP rs17182023 was correlated to reduced breast cancer risk, and was associated with FGFR1 protein expression. High FGFR1 protein expression was an independent risk factor of breast cancer, and resulted in poor prognosis.

The therapeutic targeting of the FGFR1/Src/NF-κB signaling axis inhibits pancreatic ductal adenocarcinoma stemness and oncogenicity.

The aberrant activation of the FGFR signaling is detected in many solid tumors, including pancreatic ductal adenocarcinoma (PDAC), suggesting it as a potential therapeutic target. In this study, we investigated the antitumor and anti-metastasis efficacy of the selective FGFR1 inhibitor, PD173074 in PDAC. We used immunohistochemical and in situ hybridization analyses to demonstrate a strong correlation between FGFR1 amplification and/or expression and disease progression in PDAC patients. We showed that ALDHhigh (ALDH+) pancreatic cancer cells exhibited stem cell-like phenotype and expressed higher levels of FGFR1, Src, NF-κB, alongside stemness markers like Oct4 and Sox2, compared to their ALDHlow/null (ALDH-) counterparts, suggesting the preferential activation of the FGFR1/Src/NF-κB signaling axis in pancreatic cancer stem cells (panCSCs). Furthermore, treatment of the ALDHhigh/ FGFR1-rich pancreatic cancer cell lines with PD173074, a selective FGFR1 inhibitor, revealed that PD173074 inhibited the proliferation and self-renewal of the panCSCs, and induced their apoptosis by activating caspase-3 and cleaving Poly-ADP ribose Polymerase (PARP). The anti-CSCs effect of PD173074 was associated with decreased expression of Oct4, Sox-2, Nanog, and c-Myc, as well as suppression of XIAP, Bcl2, and survivin expression, dose-dependently. Additionally, activation of cMet, Src, ERK 1/2 and NFκB (p65) was also inhibited by PD173074. Also, of clinical relevance, the disruption of the FGFR1/Src/NF-κB signaling axis positively correlated with poor clinical prognosis among the PDAC patients. We concluded that PD173074 suppresses the tumorigenesis and CSCs-like phenotype of PDAC cells, highlighting its therapeutic efficacy and providing support for its potential use as a therapeutic option for the 'difficult-to-treat', 'quick-to-relapse' PDAC patients. Schematic abstract showing how PD173074 inhibits PDAC growth through selective targeting of FGFR1, suppression of cancer stemness, disruption of the FGFR1/Src/NF-κB signaling axis and activation of the cell death signaling pathway.

Relationship and Predictive Role of the Dual Expression of FGFR and IL-8 in Metastatic Renal Cell Carcinoma Treated with Targeted Agents.

BACKGROUND/AIM: The expression of IL-8 and FGFR has been related to prognosis and pathological features in renal cell carcinoma. We investigated the relationship between IL-8 and FGFR and the outcome in metastatic renal cell carcinoma (mRCC) patients. MATERIALS AND METHODS: Clinical data and histological samples of patients affected by mRCC and treated with targeted agents were reviewed. The expression of proteins was assessed using immunohistochemistry. RESULTS: FGFR1, FGFR2, and IL-8 were found to be expressed in 16%, 30%, and 50% of cases, respectively. Significant correlations were found between selected proteins. A lack of expression of FGFR2 and IL8 was found to be correlated with increased progression-free survival (PFS). The survival rate at 24 months was 44%, 38%, and 79% of those expressing both, one, or none of the evaluated proteins, respectively (p=0.047). CONCLUSION: This analysis found a relationship between the expression of IL-8 and FGFR2 in mRCC patients treated with targeted agents.

FGF21 Protects the Blood-Brain Barrier by Upregulating PPARγ via FGFR1/ß-klotho after Traumatic Brain Injury.

Blood-brain barrier (BBB) disruption and dysfunction result in brain edema, which is responsible for more than half of all deaths after severe traumatic brain injury (TBI). Fibroblast growth factor 21 (FGF21) has a potential neuroprotective function in the brain. However, the effects and underlying possible mechanism of action on BBB integrity following TBI remain unknown. The purpose of the current study was to determine the effects of FGF21 on BBB protection and TBI treatment. The effects of recombinant human FGF21 (rhFGF21) on BBB integrity and on tight junction (TJ) and adhesion junction (AJ) proteins were investigated both in a TBI mouse model and an in vitro BBB disruption model established with tumor necrosis factor alpha (TNF-α)-induced human brain microvascular endothelial cells (HBMECs). The ability of rhFGF21 to form an FGF21/FGFR1/ß-klotho complex was confirmed by in vitro ß-klotho small interfering RNA (siRNA) transfection and FGFR1 co-immunoprecipitation. In addition, the specific FGFR1 and peroxisome proliferator-activated receptor gamma (PPARγ) inhibitors PD173074 and GW9662, respectively, were applied to further explore the possible mechanism of rhFGF21 in BBB maintenance after TBI. rhFGF21 markedly reduced neurofunctional behavior deficits and cerebral edema degree, preserved BBB integrity, and recued brain tissue loss and neuron apoptosis in the mouse model after TBI. Both in vivo and in vitro, rhFGF21 upregulated TJ and AJ proteins, thereby preserving the BBB. Moreover, rhFGF21 activated PPARγ in TNF-α-induced HBMECs through formation of an FGF21/FGFR1/ß-klotho complex. rhFGF21 protected the BBB through FGF21/FGFR1/ß-klotho complex formation and PPARγ activation, which upregulated TJ and AJ proteins.

Prognostic importance of FGF2 and FGFR1 expression for patients affected by ameloblastoma.

BACKGROUND: Fibroblast growth factor 2 (FGF2) and FGF receptor 1 (FGFR1) have been investigated in different human neoplasms and were shown to play important roles in the pathogenesis of these diseases; however, very few are known regarding their prognostic importance in the context of ameloblastoma. Therefore, the aim of this study was to investigate whether the expression of FGF2 and FGFR1 is associated with ameloblastoma clinical behavior. METHODS: Fifty-eight cases of ameloblastoma arranged in tissue microarray were submitted to immunohistochemistry against FGF2 and FGFR1. Clinicopathological parameters regarding sex, age, tumor size, duration and location, treatment, recurrences, radiographic features, cortical disruptions, and follow-up data were obtained from patients' medical records and correlated with the molecules expression. Univariate and multivariate Cox regression analyses were used to investigate the prognostic potential of the biomarkers. RESULTS: Forty-four cases (75.9%) exhibited cytoplasmic positivity for FGF2 in central and peripheral epithelial cells, 46 of 58 (79.3%) showed FGFR1 cytoplasmic positivity predominantly in the columnar peripheral cells, and 43 cases (74.1%) were positive for both. Expression of FGF2 and FGF2 + FGFR1 was associated with tumor recurrences (P = .05). However, univariate and multivariate analyses did not demonstrate a significant influence of FGF2, FGFR1, or FGF2 + FGFR1 in the 5-year disease-free survival (DFS) rate (P = .27, P = .33, and P = .25, respectively). CONCLUSION: Cytoplasmic expression of FGF2 and FGF2 + FGFR1 is associated with ameloblastoma recurrence, but FGF2 and FGFR1 are not determinants of a lower DFS.

Assessment of FGFR1 Over-Expression and Over-Activity in Lung Cancer Cells: A Toolkit for Anti-FGFR1 Drug Screening.

Lung cancer, caused mainly by smoking, is one of the most prevalent diseases in China, resulting in high mortality rates. The increasing incidence of chronic disease due to lung cancer places a huge burden on the welfare and cost to the Chinese society. Amplification of the fibroblast growth factor receptor 1 (FGFR1) is associated with high incidence and mortality in lung cancer patients. FGFR1 signaling is implicated in oncogenic traits such as proliferation, cell survival, angiogenesis, and migration. Targeting FGFR1 and its ligand basic FGF (bFGF) is a key step forward in developing new therapies for this crippling disease. Lung adenocarcinoma is the most common subtype of non-small-cell lung cancer. In this study, A549, a lung adenocarcinoma cell line widely used in vitro as a model for drug metabolism and as a transfection host, was used to study FGFR1. A stable lentiviral FGFR1 over-expression system in lung cancer cells is described for the study of anti-lung cancer drug candidates targeting FGFR1. Ligand binding to FGFR1 activates the PI3K/Akt/mTOR signaling pathway and increases adhesion, invasion, and migration in this model. Using a unique FGF monoclonal antibody developed in the laboratory, the overactive PI3K pathway was effectively blocked, abrogating the negative metastatic signaling pathways in lung cancer cells. Importantly, this model provides an effective and simple screening kit for anti-FGF1 drug compounds for lung cancer treatment and a tool for understanding the molecular mechanisms of the FGFR1 signaling pathway in lung cancer. Furthermore, this toolkit based on a FGFR1 lentiviral construct model is transferrable to study FGFR1 signaling in any type of cancer cell.

Prevalence of fibroblast growth factor receptor 1 (FGFR1) amplification in squamous cell carcinomas of the head and neck.

BACKGROUND: FGFR1 is a receptor tyrosine kinases involved in tumor growth signaling, survival, and differentiation in many solid cancer types. There is growing evidence that FGFR1 amplification might predict therapy response to FGFR1 inhibitors in squamous cell lung cancers. To estimate the potential applicability of anti FGFR1 therapies in squamous cell carcinomas of the head and neck, we studied patterns of FGFR1 amplification using fluorescence in situ hybridization (FISH). MATERIALS AND METHODS: A tissue microarray was constructed from 453 primary treatment-naive squamous cell carcinomas of the head and neck regions with histopathological and clinical follow-up data [including oral cavity (n = 222), oropharynx (n = 126), and larynx (n = 105)]. FGFR1 and centromere 8 copy numbers were assessed by dual-color FISH. FGFR1 amplification was defined as a copy number ratio FGFR1: centromere 8 ≥ 2.0. HPV sequencing and p16 immunohistochemistry (IHC) were applied to FGFR1-amplified cancers. RESULTS: FISH analysis was successful in 297 (66%) of the 453 cancers. FGFR1 amplification was found in 6% of analyzable tumors, and was more frequent in tumors of the oral cavity (13/133 amplified, 10%), than cancers of other localizations (1/79 oropharynx, 4/85 larynx; p = 0.007 and 0.159, respectively). One out of 18 FGFR1 amplified cancers was HPV positive. No associations were found between FGFR1 amplification and tumor phenotype or p16 IHC. CONCLUSIONS: Head and neck cancers are recurrently affected by FGFR1 amplification, with a predominance in cancers of the oral cavity. Finding only one HPV positive and FGFR1 amplified cancer argues against a causal relationship between HPV and FGFR1 amplifications.

Molecular characterization reveals NF1 deletions and FGFR1-activating mutations in a pediatric spinal oligodendroglioma.

Pediatric spinal oligodendrogliomas are rare and aggressive tumors. They do not share the same molecular features of adult oligodendroglioma, and no previous reports have examined the molecular features of pediatric spinal oligodendroglioma. We present the case of a child with a recurrent spinal anaplastic oligodendroglioma. We performed whole exome (paired tumor and germline DNA) and transcriptome (tumor RNA) sequencing, which revealed somatic mutations in NF1 and FGFR1. These data allowed us to explore potential personalized therapies for this patient and expose molecular drivers that may be involved in similar cases.

SOX2 Is the Determining Oncogenic Switch in Promoting Lung Squamous Cell Carcinoma from Different Cells of Origin.

Lung squamous cell carcinoma (LSCC) is a devastating malignancy with no effective treatments, due to its complex genomic profile. Therefore, preclinical models mimicking its salient features are urgently needed. Here we describe mouse models bearing various combinations of genetic lesions predominantly found in human LSCC. We show that SOX2 but not FGFR1 overexpression in tracheobronchial basal cells combined with Cdkn2ab and Pten loss results in LSCC closely resembling the human counterpart. Interestingly, Sox2;Pten;Cdkn2ab mice develop LSCC with a more peripheral location when Club or Alveolar type 2 (AT2) cells are targeted. Our model highlights the essential role of SOX2 in commanding the squamous cell fate from different cells of origin and represents an invaluable tool for developing better intervention strategies.