Evidence for a role of FGF-2 and FGF receptors in the proliferation of non-small cell lung cancer cells

Integrated analysis reveals a novel 5-fluorouracil resistance-based prognostic signature with promising implications for predicting the efficacy of chemotherapy and immunotherapy in patients with colorectal cancer

BACKGROUND

5-Fluorouracil (5-FU) has been used as a standard first-line treatment for colorectal cancer (CRC) patients. Although 5-FU-based chemotherapy and immune checkpoint blockade (ICB) have achieved success in treating CRC, drug resistance and low response rates remain substantial limitations. Thus, it is necessary to construct a 5-FU resistance-related signature (5-FRSig) to predict patient prognosis and identify ideal patients for chemotherapy and immunotherapy.

METHODS

Using bulk and single-cell RNA sequencing data, we established and validated a novel 5-FRSig model using stepwise regression and multiple CRC cohorts and evaluated its associations with the prognosis, clinical features, immune status, immunotherapy, neoadjuvant therapy, and drug sensitivity of CRC patients through various bioinformatics algorithms. Unsupervised consensus clustering was performed to categorize the 5-FU resistance-related molecular subtypes of CRC. The expression levels of 5-FRSig, immune checkpoints, and immunoregulators were determined using quantitative real-time polymerase chain reaction (RT‒qPCR). Potential small-molecule agents were identified via Connectivity Map (CMap) and molecular docking.

RESULTS

The 5-FRSig and cluster were confirmed as independent prognostic factors in CRC, as patients in the low-risk group and Cluster 1 had a better prognosis. Notably, 5-FRSig was significantly associated with 5-FU sensitivity, chemotherapy response, immune cell infiltration, immunoreactivity phenotype, immunotherapy efficiency, and drug selection. We predicted 10 potential compounds that bind to the core targets of 5-FRSig with the highest affinity.

CONCLUSION

We developed a valid 5-FRSig to predict the prognosis, chemotherapeutic response, and immune status of CRC patients, thus optimizing the therapeutic benefits of chemotherapy combined with immunotherapy, which can facilitate the development of personalized treatments and novel molecular targeted therapies for patients with CRC.

Co-Expression Network Analysis Unveiled lncRNA-mRNA Links Correlated to Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor Resistance and/or Intermediate Epithelial-to-Mesenchymal Transition Phenotypes in a Human Non-Small Cell Lung Cancer Cellular Model System

We investigated mRNA-lncRNA co-expression patterns in a cellular model system of non-small cell lung cancer (NSCLC) sensitive and resistant to the epithelial growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) erlotinib/gefitinib. The aim of this study was to unveil insights into the complex mechanisms of NSCLC targeted therapy resistance and epithelial-to-mesenchymal transition (EMT). Genome-wide RNA expression was quantified for weighted gene co-expression network analysis (WGCNA) to correlate the expression levels of mRNAs and lncRNAs. Functional enrichment analysis and identification of lncRNAs were conducted on modules associated with the EGFR-TKI response and/or intermediate EMT phenotypes. We constructed lncRNA-mRNA co-expression networks and identified key modules and their enriched biological functions. Processes enriched in the selected modules included RHO (A, B, C) GTPase and regulatory signaling pathways, apoptosis, inflammatory and interleukin signaling pathways, cell adhesion, cell migration, cell and extracellular matrix organization, metabolism, and lipid metabolism. Interestingly, several lncRNAs, already shown to be dysregulated in cancer, are connected to a small number of mRNAs, and several lncRNAs are interlinked with each other in the co-expression network.

Identification of a novel extracellular inhibitor of FGF2/FGFR signaling axis by combined virtual screening and NMR spectroscopy approach

The aberrant activation of the fibroblast growth factor 2 (FGF2)/fibroblast growth factor receptor (FGFR) signalling pathway drives severe pathologies, including cancer development and angiogenesis-driven pathologies. The perturbation of the FGF2/FGFR axis via extracellular allosteric small inhibitors is a promising strategy for developing FGFR inhibitors with improved safety and efficacy for cancer treatment. We have previously investigated the role of new extracellular inhibitors, such as rosmarinic acid (RA), which bind the FGFR-D2 domain and directly compete with FGF2 for the same binding site, enabling the disruption of the functional FGF2/FGFR interaction. To select ligands for the previously identified FGF2/FGFR RA binding site, NMR data-driven virtual screening has been performed on an in-house library of non-commercial small molecules and metabolites. A novel drug-like compound, a resorcinol derivative named RBA4 has been identified. NMR interaction studies demonstrate that RBA4 binds the FGF2/FGFR complex, in agreement with docking prediction. Residue-level NMR perturbations analysis highlights that the mode of action of RBA4 is similar to RA in terms of its ability to target the FGF2/FGFR-D2 complex, inducing perturbations on both proteins and triggering complex dissociation. Biological assays proved that RBA4 inhibited FGF2 proliferative activity at a level comparable to the previously reported natural product, RA. Identification of RBA4 chemical groups involved in direct interactions represents a starting point for further optimization of drug-like extracellular inhibitors with improved activity.

Circulating microRNAs as molecular biomarkers for lung adenocarcinoma

BACKGROUND: The potential of microRNAs (miRNAs) as molecular tumor biomarkers for early diagnosis and prognosis in lung cancer is still unclear. OBJECTIVE: To analyze expression of miRNAs in A549 lung adenocarcinoma (LUAD) cells and in primary, non-malignant bronchial epithelial (BE) cells from healthy donors. To analyze the most prominently deregulated miRNAs in plasma samples of LUAD patients and healthy donors. MATERIALS AND METHODS: The expression of 752 miRNAs in LUAD and BE cells was assessed by RT-qPCR with mean-centering restricted normalization. The relative plasma levels of 18 miRNAs in LUAD patients and healthy donors were analyzed using RT-qPCR and normalized to miR-191-5p and miR-16-3p. Putative interactions between miRNAs and their target genes were investigated in silico. RESULTS: Out of 752 miRNAs, 37 miRNAs were significantly deregulated in A549 cells compared to BE cells. MiR-15b-3p, miR-148a-3p, miR-193b-3p, and miR-195-5p were significantly deregulated in plasma samples of LUAD patients compared to donors. The target genes of those four miRNAs are involved in essential mechanisms in cancer development and progression. CONCLUSIONS: There are substantial differences between cancer and control miRNA expression in vitro and in plasma samples of LUAD patients compared to healthy donors. Four deregulated miRNAs are promising as a diagnostic biomarker for adenocarcinoma of the lung.

DYRK1A is required for maintenance of cancer stemness, contributing to tumorigenic potential in oral/oropharyngeal squamous cell carcinoma

DYRK1A, one of the dual-specificity tyrosine phosphorylation-regulated kinases (DYRKs), plays an important role in various biological processes by regulating downstream targets via kinase-dependent and independent mechanisms. Here, we report a novel role of DYRK1A in maintaining tumor growth and stemness of oral/oropharyngeal squamous cell carcinoma (OSCC) cells. Deletion of DYRK1A from OSCC cells abrogated their in vivo tumorigenicity and self-renewal capacity, the key features of cancer stem-like cells (CSCs; also referred to as tumor-initiating cells). The DYRK1A deletion also induced the suppression of CSC populations and properties, such as migration ability and chemoresistance. Conversely, ectopic expression of DYRK1A in OSCC cells augmented their CSC phenotype. Among five DYRK members (DYRK1A, 1B, 2, 3, and 4), DYRK1A is the most dominantly expressed kinase, and its expression is upregulated in OSCC compared to normal oral epithelial cells. More importantly, DYRK1A was highly enriched in various CSC-enriched OSCC populations compared to their corresponding non-CSC populations, indicating its pivotal role in cancer progression and stemness. Further, our study revealed that fibroblast growth factor 2 (FGF2) is a key regulator in the DYRK1A-mediated CSC regulation. Functional studies demonstrated that the loss of DYRK1A inhibits CSC phenotype via reduction of FGF2. Overexpression of DYRK1A promotes CSC phenotype via upregulation of FGF2. Our study delineates a novel mechanism of cancer stemness regulation by DYRK1A-FGF2 axis in OSCC. Thus, inhibition of DYRK1A would lead to a potential novel therapeutic option for targeting CSCs in OSCC.

Long non-coding RNA small nucleolar RNA host gene 1 knockdown suppresses the proliferation, migration and invasion of osteosarcoma cells by regulating microRNA-424-5p/FGF2 in vitro

The aim of the present study was to clarify the effect of long non-coding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) on the proliferation, migration and invasion of osteosarcoma (OS) cells and to explore the potential underlying mechanisms. The expression levels of SNHG1, microRNA (miR)-424-5p and fibroblast growth factor 2 (FGF2) in OS tissues and cells were detected using reverse transcription-quantitative polymerase chain reaction. OS cell proliferation, migration and invasion were analysed by MTT, wound healing and Transwell invasion assays, respectively. The targeting relationships between SNHG1 and miR-424-5p, as well as between miR-424-5p and FGF2, were confirmed using RNA-binding protein immunoprecipitation and/or dual-luciferase reporter gene assays. The results demonstrated that the expression levels of SNHG1 and FGF2 were upregulated, whereas the expression of miR-424-5p was downregulated in OS tissues and cells. The silencing of SNHG1 significantly inhibited the proliferation, migration and invasion of OS cells. Additionally, FGF2 was shown to be a target of miR-424-5p, which in turn, was a target of SNHG1. miR-424-5p silencing and FGF2 overexpression both reversed the suppressive effects of SNHG1 knockdown on the proliferation, migration and invasion of OS cells. Thus, the silencing of SNHG1 may inhibit the proliferation, migration and invasion of OS cells by regulating the miR-424-5p/FGF2 axis.

Internalized FGF-2-Loaded Nanoparticles Increase Nuclear ERK1/2 Content and Result in Lung Cancer Cell Death

Innovative cancer treatments, which improve adjuvant therapy and reduce adverse events, are desperately needed. Nanoparticles provide controlled intracellular biomolecule delivery in the absence of activating external cell surface receptors. Prior reports suggest that intracrine signaling, following overexpression of basic fibroblast growth factor (FGF-2) after viral transduction, has a toxic effect on diseased cells. Herein, the research goals were to (1) encapsulate recombinant FGF-2 within stable, alginate-based nanoparticles (ABNs) for non-specific cellular uptake, and (2) determine the effects of ABN-mediated intracellular delivery of FGF-2 on cancer cell proliferation/survival. In culture, human alveolar adenocarcinoma basal epithelial cell line (A549s) and immortalized human bronchial epithelial cell line (HBE1s) internalized ABNs through non-selective endocytosis. Compared to A549s exposed to empty (i.e., blank) ABNs, the intracellular delivery of FGF-2 via ABNs significantly increased the levels of lactate dehydrogenase, indicating that FGF-2-ABN treatment decreased the transformed cell integrity. Noticeably, the nontransformed cells were not significantly affected by FGF-2-loaded ABN treatment. Furthermore, FGF-2-loaded ABNs significantly increased nuclear levels of activated-extracellular signal-regulated kinase ½ (ERK1/2) in A549s but had no significant effect on HBE1 nuclear ERK1/2 expression. Our novel intracellular delivery method of FGF-2 via nanoparticles resulted in increased cancer cell death via increased nuclear ERK1/2 activation.

Molecular mechanism of acquired drug resistance in the EGFR-TKI resistant cell line HCC827-TR

Background

The first‐line standard treatment of non‐small cell lung cancer (NSCLC) with EGFR mutation is EGFR‐tyrosine kinase inhibitors (TKIs). However, most patients will develop acquired resistance after 9–13 months. This study investigated novel molecular mechanisms of acquired resistance to EGFR‐TKIs to identify a potential new treatment for EGFR‐TKI resistant NSCLC patients.

Methods

We established an EGFR‐TKI resistant cell line (HCC827‐TR) by culturing the HCC827‐P cell line through continuous erlotinib culture. We used Sanger sequencing, RT‐PCR, and western blot to rule out known resistance mechanisms in HCC827‐TR cells, including EGFR‐T790M and MET, PTEN, or EGFR expression changes. Next‐generation sequencing was performed and identified differentially expressed genes between two cell lines and examined the genes with GO and KEGG pathway database analyses. We also examined the molecular alterations in COSMIC and GDSC databases and performed hazard predictions using SIFT, PolyPhen‐2, Mutation Taster, and CADD.

Results

Our results identified FGF2 as a differentially expressed gene with a G101T point mutation in HCC827‐TR cells that showed high mutation frequency and hazard score. HCC827‐TR cells showed elevated FGF2 compared to parental cells. It is noteworthy that treatment with the FGFR inhibitor AZD4547 could restore the sensitivity of HCC872‐TR cells to erlotinib.

Conclusions

An erlotinib‐resistant cell line HCC827‐TR was successfully constructed and we identified the EGFR‐TKI resistance mechanism involving the FGF2 gene mutation. Targeted inhibition of the FGF2/FGFR signaling pathway may effectively restore the sensitivity of the resistant cells to erlotinib. These results suggest a novel treatment strategy for EGFR‐TKI resistant NSCLC patients.

Key points

Significant findings of the study: Identifies a novel molecular mechanism for EGFR‐TKI acquired resistance.

What this study adds: A potential novel strategy for the treatment of EGFR‐TKI resistant NSCLC patients.

The association between fibroblast growth factor receptor 1 gene amplification and lung cancer: a meta-analysis

INTRODUCTION

Identifying target oncogenic alterations in lung cancer represents a major development in disease management. We examined the association of fibroblast growth factor receptor 1 (FGFR1) gene amplification with pathological characteristics and geographic region.

MATERIAL AND METHODS

We conducted a meta-analysis of studies published between January 2010 and October 2016. Relative risks (RR) and corresponding 95% confidence intervals (CI) were calculated regarding the rate of FGFR1 amplification in different lung cancer types and geographic region.

RESULTS

Twenty-three studies (5252 patients) were included. There was heterogeneity between studies. However, in subgroup analyses for squamous cell carcinoma (SCC), small cell lung cancer (SCLC), studies using the same definition of FGFR1 amplification, and those from Australia, no significant heterogeneity was detected. The prevalence of FGFR1 amplification in these studies ranged from 4.9% to 49.2% in non-small cell lung cancer (NSCLC), 5.1% to 41.5% in SCC, 0% to 14.7% in adenocarcinoma, and 0% to 7.8% in SCLC. The prevalence of FGFR1 amplification was significantly higher in SCC than in adenocarcinoma (RR = 5.2) and SCLC (RR = 4.2). The prevalence of FGFR1 amplification ranged from 5.6% to 22.2% in Europe, 4.1% to 18.2% in the United States, 7.8% to 49.2% in Asia, and 14.2% to 18.6% in Australia. The rate of FGFR1 amplification was higher in Asians than in non-Asians (RR = 1.9) in NSCLC.

CONCLUSIONS

These results suggest that FGFR1 amplification occurs more frequently in SCC and in Asians. FGFR1 amplification may be a potential new therapeutic target for specific patients and lung cancer subtypes.

Comparing progression molecular mechanisms between lung adenocarcinoma and lung squamous cell carcinoma based on genetic and epigenetic networks: big data mining and genome-wide systems identification

Non-small-cell lung cancer (NSCLC) is the predominant type of lung cancer in the world. Lung adenocarcinoma (LADC) and lung squamous cell carcinoma (LSCC) are subtypes of NSCLC. We usually regard them as different disease due to their unique molecular characteristics, distinct cells of origin and dissimilar clinical response. However, the differences of genetic and epigenetic progression mechanism between LADC and LSCC are complicated to analyze. Therefore, we applied systems biology approaches and big databases mining to construct genetic and epigenetic networks (GENs) with next-generation sequencing data of LADC and LSCC. In order to obtain the real GENs, system identification and system order detection are conducted on gene regulatory networks (GRNs) and protein-protein interaction networks (PPINs) for each stage of LADC and LSCC. The core GENs were extracted via principal network projection (PNP). Based on the ranking of projection values, we got the core pathways in respect of KEGG pathway. Compared with the core pathways, we found significant differences between microenvironments, dysregulations of miRNAs, epigenetic modifications on certain signaling transduction proteins and target genes in each stage of LADC and LSCC. Finally, we proposed six genetic and epigenetic multiple-molecule drugs to target essential biomarkers in each progression stage of LADC and LSCC, respectively.

FGF2-FGFR1 pathway activation together with thymidylate synthase upregulation is induced in pemetrexed-resistant lung cancer cells

Pemetrexed (MTA) is a folate antimetabolite used for treating non-small cell lung cancer. To elucidate the mechanisms of pemetrexed resistance in lung cancer, we established pemetrexed-resistant sublines in PC9 (mutant EGFR) and H1993 (wild-type EGFR) lung adenocarcinoma cell lines (PC9-MTA, H1993-MTA). Gene expression profile comparison by microarray analyses revealed enhanced fibroblast growth factor 2 (FGF2) and FGF receptor 1 (FGFR1) expression, confirmed by Western blotting, enzyme-linked immunosorbent assay, and reverse transcription-polymerase chain reaction. ERK phosphorylation was increased in PC9-MTA but decreased in H1993-MTA along with decreased downstream signaling molecule phosphorylation. Cellular morphological change from epithelial to spindle-shape together with increased mesenchymal marker protein expression was observed in H1993-MTA. SiRNA-mediated FGF2 knockdown partially restored pemetrexed sensitivity in both lines, whereas anti-FGFR1 inhibitor PD173074 restored pemetrexed sensitivity in PC9-MTA. FGF2 or FGFR1 inhibition decreased pERK levels in PC9-MTA but increased pEGFR levels together with downstream signaling molecule activation and reversed epithelial-mesenchymal transition marker protein expression in H1993-MTA. Although thymidylate synthase strongly facilitates the development of pemetrexed resistance, our results reveal involvement of the FGF2-FGFR1 pathway in pemetrexed resistance in lung cancer cells and suggest that cellular function alterations induced by FGF2-FGFR1 pathway activation depend on the innate feature of cancer cells.

Lysosomal Sequestration Impairs the Activity of the Preclinical FGFR Inhibitor PD173074

Knowledge of intracellular pharmacokinetics of anticancer agents is imperative for understanding drug efficacy as well as intrinsic and acquired cellular resistance mechanisms. However, the factors driving subcellular drug distribution are complex and poorly understood. Here, we describe for the first time the intrinsic fluorescence properties of the fibroblast growth factor receptor inhibitor PD1703074 as well as utilization of this physicochemical feature to investigate intracellular accumulation and compartmentalization of this compound in human lung cancer cells. Cell-free PD173074 fluorescence, intracellular accumulation and distribution were investigated using analytical chemistry and molecular biology approaches. Analyses on a subcellular scale revealed selective drug accumulation in lysosomes. Coincubation with inhibitors of lysosomal acidification strongly enhanced PD173074-mediated fibroblast growth factor receptor (FGFR) inhibition and cytotoxicity. In conclusion, intrinsic fluorescence enables analysis of molecular factors influencing intracellular pharmacokinetics of PD173074. Lysosome-alkalinizing agents might represent candidates for rational combination treatment, preventing cancer cell-intrinsic PD173074 resistance based on lysosomal trapping.

The FGF2 aptamer inhibits the growth of FGF2-FGFR pathway driven lung cancer cells

Cancers, including lung cancer, are a leading cause of death worldwide. To overcome this deadly disease, multiple modality inhibitors have been developed. These include cytotoxic agents, molecular targeted small molecules, such as tyrosine kinase inhibitors, and neutralizing antibodies. An aptamer is a short single-stranded nucleic acid molecule that is selected in vitro from a large random sequence library based on its high and specific affinity to a target molecule. Aptamers can be applied to therapeutics of various types of diseases, including cancer, due to their strong and specific neutralizing activities. However, the efficacy of aptamer-based therapy for cancer cells is not well characterized. In this study, we aimed to show that the FGF2 aptamer is effective for the treatment of FGF2 dependent lung cancer cells. We previously developed PC9GR lung cancer cells, whose proliferation is dependent on EGFR and FGF2-FGFR pathways in a cell autonomous manner. Using PC9GR cells, we demonstrate that the addition of the FGF2 aptamer induces more significant inhibition of PC9GR cell proliferation than does the addition of EGFR inhibitor alone. Furthermore, the addition of the FGF2 aptamer more significantly inhibits the downstream signals and induces apoptosis to a higher extent than does the addition of EGFR inhibitor alone. Our results show that the FGF2 aptamer inhibits the growth of FGF2-FGFR pathway-dependent lung cancer cells. The findings provide preclinical evidence that aptamers can be useful for cancer treatment.

Acquired nintedanib resistance in FGFR1-driven small cell lung cancer: role of endothelin-A receptor-activated ABCB1 expression

Genomically amplified fibroblast growth factor receptor 1 (FGFR1) is an oncogenic driver in defined lung cancer subgroups and predicts sensibility against FGFR1 inhibitors in this patient cohort. The FGFR inhibitor nintedanib has recently been approved for treatment of lung adenocarcinoma and is currently evaluated for small cell lung cancer (SCLC). However, tumor recurrence due to development of nintedanib resistance might occur. Hence, we aimed at characterizing the molecular mechanisms underlying acquired nintedanib resistance in FGFR1-driven lung cancer. Chronic nintedanib exposure of the FGFR1-driven SCLC cell line DMS114 (DMS114/NIN) but not of two NSCLC cell lines induced massive overexpression of the multidrug-resistance transporter ABCB1. Indeed, we proved nintedanib to be both substrate and modulator of ABCB1-mediated efflux. Importantly, the oncogenic FGFR1 signaling axis remained active in DMS114/NIN cells while bioinformatic analyses suggested hyperactivation of the endothelin-A receptor (ET_AR) signaling axis. Indeed, ET_AR inhibition resensitized DMS114/NIN cells against nintedanib by downregulation of ABCB1 expression. PKC and downstream NFκB were identified as major downstream players in ET_AR-mediated ABCB1 hyperactivation. Summarizing, ABCB1 needs to be considered as a factor underlying nintedanib resistance. Combination approaches with ET_AR antagonists or switching to non-ABCB1 substrate FGFR inhibitors represent innovative strategies to manage nintedanib resistance in lung cancer.

Therapeutic and pathological roles of fibroblast growth factors in pulmonary diseases

Fibroblast growth factors (FGFs) constitute a large family of polypeptides that are involved in many biological processes, ranging from prenatal cell-fate specification and organogenesis to hormonal and metabolic regulation in postnatal life. During embryonic development, these growth factors are important mediators of the crosstalk among ectoderm-, mesoderm-, and endoderm-derived cells, and they instruct the spatial and temporal growth of organs and tissues such as the brain, bone, lung, gut, and others. The involvement of FGFs in postnatal lung homeostasis is a growing field, and there is emerging literature about their roles in lung pathophysiology. In this review, the involvement of FGF signaling in a wide array of lung diseases will be summarized. Developmental Dynamics 246:235-244, 2017. © 2016 Wiley Periodicals, Inc.

Anti-cancer activities of Brassica juncea leaves in vitro

Mustard (Brassica juncea) leaves are commonly consumed in different Asian and African countries. Cancer is a major burden of disease worldwide, and the colorectal and lung cancers are the leading cause of morbidity and mortality among cancers. In the current study, we aimed to investigate the effects of ethanol extract of mustard leaf (MLE) on the growth, angiogenic, and metastatic potentials of HCT116 colorectal carcinoma and H1299 non-small cell lung carcinoma cells in vitro. Treatment of HCT116 and H1299 cells with MLE inhibited cell growth in a dose-dependent manner (in the range of 175-700 µg/ml, by 39-86 %) and anchorage-independent colonization (at 700 µg/ml, by 56-86 %). Induction of apoptosis by MLE was evidenced by heterogeneous and condensed nucleus morphology, increased 4′,6-diamidino-2-phenylindole dihydrochloride staining intensity, and elevated sub-G1 cell population. In both HCT116 and H1299 cells, treatment with MLE markedly suppressed the secretion of key pro-angiogenic factors, such as vascular endothelial cell growth factor (by >92 %) and basic fibroblast growth factor (by 73-94 %). MLE was also effective in inhibiting critical events during metastasis, such as invasion (by 18-33 % in HCT116 and H1299), migration (45-82 % in H1299), and adhesion (by 17-45 % in HCT116 and H1299). These results indicate that MLE possesses in vitro anti-cancer activities against colon and lung cancers. It needs to be verified whether similar effects are reproduced in vivo.

FGFR1, 2 and 3 protein overexpression and molecular aberrations of FGFR3 in early stage non-small cell lung cancer

This study aimed to determine protein expression levels of fibroblast growth factor receptors (FGFR) 1, 2 and 3 in early stage non‐small cell lung cancer (NSCLC). Additionally, a screen to define the frequency of FGFR3‐TACC3 translocation and FGFR3 amplification was performed. Archived tissues from 653 NSCLC samples (adenocarcinoma (AC), squamous cell carcinoma (SCC) and large cell carcinoma (LCC)) were analysed with immunohistochemistry (IHC) for expression of FGFR1, 2 and 3. Expression levels of FGFR1, 2 and 3 were correlated with clinicopathological features. The presence of FGFR3‐TACC3 translocation was detected by RT‐PCR and FGFR3 amplification was detected by fluorescence in situ hybridization. FGFR1, 2 and 3 proteins were highly expressed in 64 (10.6%), 76 (12.9%) and 20 (3.3%) NSCLC tumour samples, respectively. Protein expression of FGFR1 was significantly related to worse overall survival in NSCLC. Furthermore, FGFR1 protein expression was associated with light smoking and histological subtype (AC), FGFR2 protein expression with female gender, younger age, histological subtype (AC) and lower tumour stage, and FGFR3 protein was significantly overexpressed in tumours of older patients and SCC histology. The FGFR3‐TACC3 fusion was detected in 3.0% (6/200) of NSCLC samples and the FGFR3 gene was amplified in 4.7% of IHC positive NSCLC samples (2/43). FGFR1, 2 and 3 proteins are expressed in a high number of early stage NSCLC and FGFR1 protein expression may serve as a prognostic biomarker. Recurrent translocations and amplifications in FGFR3 can be found in NSCLC. This study shows that FGFR family members are frequently aberrant in NSCLC and could be interesting therapeutic targets for the treatment of NSCLC.

Characterization of FGFR signaling pathway as therapeutic targets for sarcoma patients

The fibroblast growth factor receptor (FGFR) family plays important roles in regulating cell growth, proliferation, survival, differentiation and angiogenesis. Deregulation of the FGF/FGFR signaling pathway has been associated with multiple development syndromes and cancers, and thus therapeutic strategies targeting FGFs and FGFR in human cancer are currently being explored. However, few studies on the FGF/FGFR pathway have been conducted in sarcoma, which has a poor outcome with traditional treatments such as surgery, chemotherapy, and radiotherapy. Hence, in the present review, we provide an overview of the role of the FGF/FGFR pathway signal in sarcoma and FGFR inhibitors, which might be new targets for the treatment of sarcomas according to recent research.

Amplification of FGFR1 gene and expression of FGFR1 protein is found in different histological types of lung carcinoma

Although lung cancer continues to be the leading cause of cancer-related death, accurate diagnosis followed by personalized treatment is expected to raise the 5-year survival rate. Targeted therapies are now in routine clinical use, in particular for lung adenocarcinoma (ADC). Fibroblast growth factor receptor 1 (FGFR1) has recently emerged as a molecular target, especially in squamous cell/epidermoid carcinoma (SQC) of the lung. This paper evaluates FGFR1 expression and gene copy number in adenocarcinomas, squamous cell carcinomas, pleomorphic carcinomas (PLEOMC) and adenosquamous carcinomas (ADSQC) of the lung and also explores the epithelial-mesenchymal transition (EMT) pathway. We studied 76 lung carcinomas: 34 ADC, 24 SQC, 10 PLEOMC and 8 ADSQC. FGFR1 expression was evaluated by immunohistochemistry and gene amplification by fluorescence in situ hybridization (FISH). Higher FGFR1 protein expression was observed in all tumour types compared to non-tumour tissue. FGFR1 expression was higher in ADC and PLEOMC than in SQC. We found a tendency to higher expression in ADC than in SQC and significantly higher expression in PLEOMC than in other histological subtypes. FISH-based amplification of FGFR1 was identified in 15 (20 %) lung carcinomas: 5 (15 %) ADC, 5 (21 %) SQC, 3 (30 %) PLEOMC and 2 (25 %) ADSQC. Amplification was more frequent in SQC without significant differences. FGFR1 protein is expressed in the majority of lung carcinomas, though it is higher in ADC and PLEOMC (the latter may reflect the importance of FGFR1 control of the EMT pathway). FGFR1 amplification was identified in all types of lung carcinoma. Although FGFR1 is most frequently amplified in SQC, other histological types merit assessment of FGFR1 amplification, in order to select patients that might benefit from targeted therapy.

Endothelial Rictor is crucial for midgestational development and sustained and extensive FGF2-induced neovascularization in the adult

To explore the general requirement of endothelial mTORC2 during embryonic and adolescent development, we knocked out the essential mTORC2 component Rictor in the mouse endothelium in the embryo, during adolescence and in endothelial cells in vitro. During embryonic development, Rictor knockout resulted in growth retardation and lethality around embryonic day 12. We detected reduced peripheral vascularization and delayed ossification of developing fingers, toes and vertebrae during this confined midgestational period. Rictor knockout did not affect viability, weight gain, and vascular development during further adolescence. However during this period, Rictor knockout prevented skin capillaries to gain larger and heterogeneously sized diameters and remodeling into tortuous vessels in response to FGF2. Rictor knockout strongly reduced extensive FGF2-induced neovascularization and prevented hemorrhage in FGF2-loaded matrigel plugs. Rictor knockout also disabled the formation of capillary-like networks by FGF2-stimulated mouse aortic endothelial cells in vitro. Low RICTOR expression was detected in quiescent, confluent mouse aortic endothelial cells, whereas high doses of FGF2 induced high RICTOR expression that was associated with strong mTORC2-specific protein kinase Cα and AKT phosphorylation. We demonstrate that the endothelial FGF-RICTOR axis is not required during endothelial quiescence, but crucial for midgestational development and sustained and extensive neovascularization in the adult.

Direct Melanoma Cell Contact Induces Stromal Cell Autocrine Prostaglandin E2-EP4 Receptor Signaling That Drives Tumor Growth, Angiogenesis, and Metastasis

The stromal cells associated with tumors such as melanoma are significant determinants of tumor growth and metastasis. Using membrane-bound prostaglandin E synthase 1 (mPges1(-/-)) mice, we show that prostaglandin E2 (PGE2) production by host tissues is critical for B16 melanoma growth, angiogenesis, and metastasis to both bone and soft tissues. Concomitant studies in vitro showed that PGE2 production by fibroblasts is regulated by direct interaction with B16 cells. Autocrine activity of PGE2 further regulates the production of angiogenic factors by fibroblasts, which are key to the vascularization of both primary and metastatic tumor growth. Similarly, cell-cell interactions between B16 cells and host osteoblasts modulate mPGES-1 activity and PGE2 production by the osteoblasts. PGE2, in turn, acts to stimulate receptor activator of NF-κB ligand expression, leading to osteoclast differentiation and bone erosion. Using eicosanoid receptor antagonists, we show that PGE2 acts on osteoblasts and fibroblasts in the tumor microenvironment through the EP4 receptor. Metastatic tumor growth and vascularization in soft tissues was abrogated by an EP4 receptor antagonist. EP4-null Ptger4(-/-) mice do not support B16 melanoma growth. In vitro, an EP4 receptor antagonist modulated PGE2 effects on fibroblast production of angiogenic factors. Our data show that B16 melanoma cells directly influence host stromal cells to generate PGE2 signals governing neoangiogenesis and metastatic growth in bone via osteoclast erosive activity as well as angiogenesis in soft tissue tumors.

The potential of fibroblast growth factor/fibroblast growth factor receptor signaling as a therapeutic target in tumor angiogenesis

INTRODUCTION

Fibroblast growth factors (FGFs) are endowed with a potent pro-angiogenic activity. Activation of the FGF/FGF receptor (FGFR) system occurs in a variety of human tumors. This may lead to neovascularization, supporting tumor progression and metastatic dissemination. Thus, a compelling biologic rationale exists for the development of anti-FGF/FGFR agents for the inhibition of tumor angiogenesis in cancer therapy.

AREAS COVERED

A comprehensive search on PubMed was performed to identify studies on the role of the FGF/FGFR system in angiogenesis. Endothelial FGFR signaling, the pro-angiogenic function of canonical FGFs, and their role in human tumors are described. In addition, experimental approaches aimed at the identification and characterization of nonselective and selective FGF/FGFR inhibitors and their evaluation in clinical trials are summarized.

EXPERT OPINION

Different approaches can be envisaged to inhibit the FGF/FGFR system, a target for the development of 'two-compartment' anti-angiogenic/anti-tumor agents, including FGFR selective and nonselective small-molecule tyrosine kinase inhibitors, anti-FGFR antibodies, and FGF ligand traps. Further studies are required to define the correlation between tumor vascularization and activation of the FGF/FGFR system and for the identification of cancer patients more likely to benefit from anti-FGF/FGFR treatments. In addition, advantages and disadvantages about the use of selective versus non-selective FGF inhibitors remain to be elucidated.

Nintedanib: from discovery to the clinic

Nintedanib (BIBF1120) is a potent, oral, small-molecule tyrosine kinase inhibitor, also known as a triple angiokinase inhibitor, inhibiting three major signaling pathways involved in angiogenesis. Nintedanib targets proangiogenic and pro-fibrotic pathways mediated by the VEGFR family, the fibroblast growth factor receptor (FGFR) family, the platelet-derived growth factor receptor (PDGFR) family, as well as Src and Flt-3 kinases. The compound was identified during a lead optimization program for small-molecule inhibitors of angiogenesis and has since undergone extensive clinical investigation for the treatment of various solid tumors, and in patients with the debilitating lung disease idiopathic pulmonary fibrosis (IPF). Recent clinical evidence from phase III studies has shown that nintedanib has significant efficacy in the treatment of NSCLC, ovarian cancer, and IPF. This review article provides a comprehensive summary of the preclinical and clinical research and development of nintedanib from the initial drug discovery process to the latest available clinical trial data.

MiR-152 suppresses the proliferation and invasion of NSCLC cells by inhibiting FGF2

MicroRNAs (miRNAs) regulate the proliferation and metastasis of cancer cells. Here, we showed that miR-152 was downregulated in non-small-cell lung cancer (NSCLC) tissues and cell lines. Overexpression of miR-152 suppressed cell proliferation and colony formation and also limited migration and invasion. Fibroblast growth factor 2 (FGF2) was confirmed as a direct target of miR-152. FGF2 knockdown suppressed cell proliferation, colony formation, migration and invasion, whereas FGF2 overexpression partially reversed the suppressive effect of miR-152. Furthermore, the presence of miR-152 was inversely correlated with FGF2 in NSCLC tissues. Overall, this study demonstrated that miR-152 suppressed the proliferation and invasion of NSCLC cells by downregulating FGF2. These findings provide novel insights with potential therapeutic applications for the treatment of NSCLC.

[Advanced research of fibroblast growth factor receptor in non-small cell lung cancer]

Lung cancer is severely threatening human health. In recent years, the treatment for lung adenocarcinoma has made a great progress, targeted therapy has been widely applied in clinic, and benefits amount of patients. However, in squamous cell lung cancer, the incidence of epidermal growth factor receptor (EGFR) gene mutant and ALK fusion gene are low,and targeted therapy like Tarceva and crizotinib, can hardly work. Since the fibroblast growth factors (fibroblast growth factor, FGF) pathway is considered to be related to tumor cell proliferation, metastasis and angiogenesis, more and more researches proved the amplification of fibroblast growth factor receptor (FGFR) in squamous cell lung cancer. Experiments in vivo and in vitro found that blocking FGF pathway could reduce the proliferation of tumor cells and inhibit metastasis. The FGF pathway might be a new target for treatment of squamous cell lung cancer. This article reviews the effect of FGFR in tumorigenesis,as well as the prospect as a therapeutic target in non-small cell lung cancer.

Fibroblast growth factor 2 is of prognostic value for patients with locally advanced squamous cell carcinoma of the head and neck

BACKGROUND AND PURPOSE

Patients with locally advanced SCCHN have a poor prognosis. This study investigated the prognostic value of the tumor cell expression of the fibroblast growth factor 2 (FGF-2) in patients treated with surgery followed by radiotherapy.

PATIENTS AND METHODS

The impact of FGF-2-expression and 11 additional potential prognostic factors on loco-regional control (LRC), metastases-free survival (MFS), and overall survival (OS) was retrospectively evaluated in 146 patients. Additional factors included age, gender, performance status, pre-radiotherapy hemoglobin levels, tumor site, histologic grade, T-category, N-category, human papilloma virus (HPV) status, extent of resection, and chemotherapy. Univariate analyses were performed with the Kaplan-Meier method and the log-rank test, multivariate analyses with the Cox proportional hazard model.

RESULTS

On multivariate analysis, improved LRC was significantly associated with FGF-2-negativity [risk ratio (RR): 7.33; 95%-confidence interval (CI): 2.88-19.05; p<0.001], lower T-category (RR: 2.42; 95%-CI: 1.47-4.33; p<0.001), lower N-category (RR: 12.36; 95%-CI: 3.48-78.91; p<0.001), and pre-radiotherapy hemoglobin levels ≥ 12 g/dl (RR: 4.18; 95%-CI: 1.73-10.53; p=0.002). No factor was significantly associated with improved MFS. Lower T-category showed a trend (RR: 1.59; 95%-CI: 0.97-2.82; p=0.069). Better OS was significantly associated with FGF-2-negativity (RR: 5.10; 2.22-11.80; p<0.001), lower T-category (RR: 2.17; 95%-CI: 1.38-3.68; p < 0.001), lower N-category (RR: 3.86; 95%-CI: 1.60-10.85; p=0.002), and pre-radiotherapy hemoglobin levels ≥ 12 g/dl (RR: 3.20; 95%-CI: 1.46-7.30; p=0.004). HPV-positivity showed a trend (RR: 2.36; 95%-CI: n.a.; p=0.054).

CONCLUSIONS

Tumor cell expression of FGF-2 proved to be an independent prognostic factor for LRC and OS. This factor can help personalize treatment and stratify patients in future trials.

Activation of the FGF2-FGFR1 autocrine pathway: a novel mechanism of acquired resistance to gefitinib in NSCLC

Patients with non-small cell lung cancer (NSCLC) that harbors epidermal growth factor receptor (EGFR) mutations initially respond to EGFR-tyrosine kinase inhibitors (TKI) but eventually experience relapse. Acquired resistance to EGFR-TKIs is strongly associated with patient mortality. Thus, elucidation of the mechanism of acquired resistance to EGFR-TKIs is of great importance. In this study, gefitinib-resistant cell line models were established by long-term exposure to gefitinib using the gefitinib-sensitive lung cancer cell lines, PC9 and HCC827. Expression analyses indicated that both FGFR1 and FGF2 were increased in PC9 gefitinib-resistant (PC9 GR) cells as compared with PC9 naïve (PC9 na) cells. Importantly, proliferation of gefitinib-resistant cells was dependent on the FGF2 -FGFR1 pathway. Mechanistically, inhibition of either FGF2 or FGFR1 by siRNA or FGFR inhibitor (PD173074) restored gefitinib sensitivity in PC9 GR cells. These data suggest that FGF2 -FGFR1 activation through an autocrine loop is a novel mechanism of acquired resistance to EGFR-TKIs.

Protein arginine methyltransferase 5 is essential for growth of lung cancer cells

PRMT5 (protein arginine methyltransferase 5) is an enzyme that catalyses transfer of methyl groups from S-adenosyl methionine to the arginine residues of histones or non-histone proteins and is involved in a variety of cellular processes. Although it is highly expressed in some tumours, its direct role in cancer growth has not been fully investigated. In the present study, in human lung tissue samples we found that PRMT5 was highly expressed in lung cancer cells, whereas its expression was not detectable in benign lung tissues. Silencing PRMT5 expression strongly inhibited proliferation of lung adenocarcinoma A549 cells in tissue culture, and silencing PRMT5 expression in A549 cells also abolished growth of lung A549 xenografts in mice. In vitro and in vivo studies showed that the cell growth arrest induced by loss of PRMT5 expression was partially attributable to down-regulation of fibroblast growth factor receptor signalling. These results suggest that PRMT5 and its methyltransferase activity is essential for proliferation of lung cancer cells and may serve as a novel target for the treatment of lung cancer.

Increased expression of fibroblastic growth factor receptor 2 is correlated with poor prognosis in patients with breast cancer

BACKGROUND AND OBJECTIVES

Although there is growing evidence supporting the hypothesis that fibroblast growth factor receptor 2 (FGFR2) is one of the few candidate genes linked with breast cancer susceptibility, the precise role of FGFR2 protein expression in breast cancer is still unknown. Our study examines FGFR2 protein expression in breast cancer and determines its associations with clinicopathological features and survival.

METHODS

Specimens from 125 invasive ductal carcinoma grade 2 (IDC2) breast cancer patients were investigated by immunohistochemistry for FGFR2 protein expression. Associations between the expression of FGFR2 and various clinicopathological features as well as survival status were studied.

RESULT

Cytoplasmic and nuclear FGFR2 were expressed in 64.8% and 56.8% of breast cancer patients, respectively. Cytoplasmic FGFR2 expression was significantly associated with tumor size and TNM stage. Furthermore, patients with high expression levels of cytoplasmic and nuclear FGFR2 showed much lower overall survival (OS) and disease-free survival (DFS) rates than those patients with low FGFR2 expression. Cytoplasmic FGFR2 expression and lymph node metastasis were independent prognostic factors for both DFS and OS by multivariate analysis.

CONCLUSIONS

High FGFR2 expression is correlated with poor OS and DFS in breast cancer patients. It could be a biomarker for poor prognosis.

Upregulated FGFR1 expression is associated with the transition of hormone-naive to castrate-resistant prostate cancer

BACKGROUND

Prostate cancer (PC) represents a global health issue. Treatment for locally advanced and metastatic PC remains unsatisfactory. The androgen receptor (AR) has been validated in having a key role in both naïve and castrate-resistant PC (CRPC). However, the significance of other signalling pathways in CRPC is less well validated.

METHODS

To gain a better insight into the molecular signalling cascades involved in clinical CRPC, we performed gene expression profiling using the Illumina DASL assay and studied matched hormone-naive (HN) and CR prostate tumours (n=10 pairs). Ingenuity Pathways Analysis (IPA) was used to identify potential networks involved, and further validation was performed in in vitro cell models and clinical tumours.

RESULTS

Expression of 50 genes was significantly different between HN and CRPC. IPA revealed two networks of particular interest, including AR and FGFR1, respectively. FGFR1 expression was confirmed to be significantly upregulated in CRPC (P ≤ 0.005), and abnormal FGFR1 expression was associated with shorter time to biochemical relapse in HNPC (P=0.006) and less favourable disease-specific survival in CRPC (P=0.018).

CONCLUSION

For the first time, our gene expression profiling experiment on archival tumour materials has identified upregulated FGFR1 expression to be associated with PC progression to the CR state.

Beyond VEGF: inhibition of the fibroblast growth factor pathway and antiangiogenesis

Fibroblast growth factor (FGF) signaling regulates cell proliferation, differentiation, survival, angiogenesis, and wound healing. Compelling evidence for deregulated FGF signaling in tumorigenesis continues to emerge, and a growing body of research suggests that FGF may also play an integral role in the resistance to anti-VEGF therapy. Although agents targeting FGF signaling are early in development, the potential to target both the VEGF and FGF pathways may translate into improvements in the clinical care of cancer patients.

Fibroblast growth factor receptors as therapeutic targets in human melanoma: synergism with BRAF inhibition

Cutaneous melanoma is a tumor with rising incidence and a very poor prognosis at the disseminated stage. Melanomas are characterized by frequent mutations in BRAF and also by overexpression of fibroblast growth factor 2 (FGF2), offering opportunities for therapeutic intervention. We investigated inhibition of FGF signaling and its combination with dacarbazine or BRAF inhibitors as an antitumor strategy in melanoma. The majority of melanoma cell lines displayed overexpression of FGF2 but also FGF5 and FGF18 together with different isoforms of FGF receptors (FGFRs) 1-4. Blockade of FGF signals with dominant-negative receptor constructs (dnFGFR1, 3, or 4) or small-molecule inhibitors (SU5402 and PD166866) reduced melanoma cell proliferation, colony formation, as well as anchorage-independent growth, and increased apoptosis. DnFGFR constructs also significantly inhibited tumor growth in vivo. Combination of FGF inhibitors with dacarbazine showed additive or antagonistic effects, whereas synergistic drug interaction was observed when combining FGFR inhibition with the multikinase/BRAF inhibitor sorafenib or the V600E mutant-specific BRAF inhibitor RG7204. In conclusion, FGFR inhibition has antitumor effects against melanoma cells in vitro and in vivo. Combination with BRAF inhibition offers a potential for synergistic antimelanoma effects and represents a promising therapeutic strategy against advanced melanoma.

Comparison of angiotensin converting enzyme inhibitors and angiotensin II type 1 receptor blockade for the prevention of premalignant changes in the liver

AIM

We investigate and compare the possible antitumor activity of clinically used angiotensin converting enzyme (ACE) inhibitors; captopril, perindopril and angiotensin II type 1 receptor (AT1R) blocker, losartan against hepatocarcinogenesis initiated by diethylnitrosoamines (DENA) and promoted by carbon tetrachloride (CCl(4)).

MAIN METHODS

Diethylnitrosamine (DENA) (200mg/kgi.p.) initiated and carbon tetrachloride (CCl(4)) (2ml/kgi.p.) promoted hepatocarcinogenesis in male Wistar rats after 8weeks.

RESULTS

Hepatocarcinogenesis was manifested biochemically by elevation of serum hepatic tumor markers tested; α-feto protein (AFP) and carcinoembryonic antigen (CEA). In addition, hepatic carcinogenesis was further confirmed by a significant increase in hepatic tissue growth factors; vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF). Moreover a marked increase in matrix metalloproteinase-2 and hydroxyproline content were also observed. Hepatocarcinogenesis was further confirmed by a significant decrease in hepatic endostatin and metallothonein level.

KEY FINDINGS

Long-term administration of the selected drugs for 2weeks before and throughout the experimental period produced a significant protection against hepatic carcinogenesis. The present results claimed that different doses of the selected drugs succeeded in normalization of serum tumor markers. Furthermore, the drugs reduced the elevated level in the hepatic growth factors, matrix metalloproteinase-2 and hydroxyproline induced by the hepatocarcinogen. Moreover, the amelioration was also accompanied by augmentation of hepatic content of metallothionein and endostatin. Histopathological examination of liver tissues of rats treated with DENA-CCl(4) correlated with the biochemical observations.

SIGNIFICANCE

These findings suggest a similar protective effect of ACE inhibitors; captopril; perindopril and AT1R blocker, losartan against premalignant stages of liver cancer in the DENA initiated and CCl(4) promoted hepatocarcinogenesis model in rats. Therefore, RAS especially angiotensin II (Ang II) and AT1R interaction plays a pivotal role hepatocarcinogenesis development.

Tailoring tyrosine kinase inhibitors to fit the lung cancer genome

Tyrosine kinase inhibitors (TKIs) have been in use as cancer therapeutics for nearly a decade, and their utility in targeting specific malignancies with defined genetic lesions has proven to be remarkably effective. Recent efforts to characterize the spectrum of genetic lesions found in non-small cell lung carcinoma (NSCLC) have provided important insights into the molecular basis of this disease and have also revealed a wide array of tyrosine kinases that might be effectively targeted for rationally designed therapies. The findings of these studies, however, also provide a cautionary tale about the limitations of single-agent therapies, which fail to account for the genetic heterogeneity and pathway redundancy that characterize advanced NSCLC. Emergence of drug resistance mechanisms to specific TKIs, such as gefitinib and erlotinib, suggests that more sophisticated chemotherapeutic paradigms that target multiple pathways at the same time will be required to effectively treat this disease.

Targeting fibroblast-growth-factor-receptor-dependent signaling for cancer therapy

INTRODUCTION

Fibroblast growth factors (FGF) exert a combination of biological effects that contribute to four of the six essential hallmarks of cancer. It is no surprise that FGF-dependent signaling has increasingly moved to the center of cancer therapy research during the past decade. This is illustrated by the large number of publications focusing on various aspects of this theme that have been published in the past 5 years.

AREAS COVERED

Information from these sources as well as ongoing work from the authors' groups is used to outline the physiological functions of FGF signaling and to highlight how the high oncogenic effects of deregulated FGFs and FGFRs derive from their physiological functions. The biological effect of deregulated FGFR signaling in malignant diseases is described and the current state of therapeutic targeting of FGFR is summarized.

EXPERT OPINION

Strategies for targeting FGFR-signaling for cancer therapy are very promising, but need to be carefully developed based on the physiological roles of FGF signaling. Preventive measures may be necessary for protection from FGF-related side effects. Combined targeting of several receptor tyrosine kinases or combination with other therapies may be a useful way of avoiding or ameliorating side effects. FGF-related markers of prognosis and therapy response still need to be investigated.

Rapidly acquired resistance to EGFR tyrosine kinase inhibitors in NSCLC cell lines through de-repression of FGFR2 and FGFR3 expression

Despite initial and sometimes dramatic responses of specific NSCLC tumors to EGFR TKIs, nearly all will develop resistance and relapse. Gene expression analysis of NSCLC cell lines treated with the EGFR TKI, gefitinib, revealed increased levels of FGFR2 and FGFR3 mRNA. Analysis of gefitinib action on a larger panel of NSCLC cell lines verified that FGFR2 and FGFR3 expression is increased at the mRNA and protein level in NSCLC cell lines in which the EGFR is dominant for growth signaling, but not in cell lines where EGFR signaling is absent. A luciferase reporter containing 2.5 kilobases of fgfr2 5′ flanking sequence was activated after gefitinib treatment, indicating transcriptional regulation as a contributing mechanism controlling increased FGFR2 expression. Induction of FGFR2 and FGFR3 protein as well as fgfr2-luc activity was also observed with Erbitux, an EGFR-specific monoclonal antibody. Moreover, inhibitors of c-Src and MEK stimulated fgfr2-luc activity to a similar degree as gefitinib, suggesting that these pathways may mediate EGFR-dependent repression of FGFR2 and FGFR3. Importantly, our studies demonstrate that EGFR TKI-induced FGFR2 and FGFR3 are capable of mediating FGF2 and FGF7 stimulated ERK activation as well as FGF-stimulated transformed growth in the setting of EGFR TKIs. In conclusion, this study highlights EGFR TKI-induced FGFR2 and FGFR3 signaling as a novel and rapid mechanism of acquired resistance to EGFR TKIs and suggests that treatment of NSCLC patients with combinations of EGFR and FGFR specific TKIs may be a strategy to enhance efficacy of single EGFR inhibitors.

Ginger ingredients inhibit the development of diethylnitrosoamine induced premalignant phenotype in rat chemical hepatocarcinogenesis model

To investigate the possible antitumor activity of ginger extract against hepatic carcinogenesis initiated by diethylnitrosoamines (DEN) and promoted by carbon tetrachloride (CCl(4) ). A total of 60 male Wistar albino rats were divided into four groups with 15 animals in each group. Rats in group 1 (control group) received a single intraperitoneal (i.p.) injection of normal saline. Animals in group 2 were given ginger (50 mg/kg/day) in drinking water for 8 weeks. Rats in group 3 (DEN group) were injected with a single dose of DEN (200 mg/kg, i.p.), 2 weeks later received a single dose of CCl(4) (2 mL/kg i.g) by gavage as 1:1 dilution in corn oil. Animals in group 4 (DEN-ginger group) received the same carcinogenesis induction protocol as in group 3 plus ginger (50 mg/kg/day) in drinking water for 2 weeks before induction of hepatocarcinogenesis and continued throughout the experimental period. DEN-initiated and CCl(4) -promoted hepatocarcinogenesis in male Wistar rats was manifested biochemically by elevation of serum hepatic tumor markers tested; α-fetoprotein and carcinoembryonic antigen. In addition, hepatocarcinogenesis was further confirmed by a significant increase in hepatic tissue growth factors; vascular endothelial growth factor, basic fibroblast growth factor, and hydroxyproline content. A marked decrease in endostatin and metallothonein were also observed. Long-term ginger extract administration 2 weeks before induction of hepatocarcinogenesis and throughout the experimental period prevented the decrease of the hepatic content of metallothionein and endostatin and the increase in the growth factors induced by the carcinogen. Moreover, ginger extract normalize serum hepatic tumor markers. Histopathological examination of liver tissue also correlated with the biochemical observations. These findings suggest a protective effect of ginger extract against premalignant stages of liver cancer in the DEN-initiated and CCl(4) -promoted hepatocarcinogenesis model in rats.

Fibroblast growth factor 2--a predictor of outcome for patients irradiated for stage II-III non-small-cell lung cancer

PURPOSE

The prognostic value of the tumor cell expression of the fibroblast growth factor 2 (FGF-2) in patients with non-small-cell lung cancer (NSCLC) is unclear. The present study investigated the effect of tumor cell expression of FGF-2 on the outcome of 60 patients irradiated for Stage II-III NSCLC.

METHODS AND MATERIALS

The effect of FGF-2 expression and 13 additional factors on locoregional control (LRC), metastasis-free survival (MFS), and overall survival (OS) were retrospectively evaluated. These additional factors included age, gender, Karnofsky performance status, histologic type, histologic grade, T and N category, American Joint Committee on Cancer stage, surgery, chemotherapy, pack-years, smoking during radiotherapy, and hemoglobin during radiotherapy. Locoregional failure was identified by endoscopy or computed tomography. Univariate analyses were performed with the Kaplan-Meier method and the Wilcoxon test and multivariate analyses with the Cox proportional hazard model.

RESULTS

On univariate analysis, improved LRC was associated with surgery (p = .017), greater hemoglobin levels (p = .036), and FGF-2 negativity (p <.001). On multivariate analysis of LRC, surgery (relative risk [RR], 2.44; p = .037), and FGF-2 expression (RR, 5.06; p <.001) maintained significance. On univariate analysis, improved MFS was associated with squamous cell carcinoma (p = .020), greater hemoglobin levels (p = .007), and FGF-2 negativity (p = .001). On multivariate analysis of MFS, the hemoglobin levels (RR, 2.65; p = .019) and FGF-2 expression (RR, 3.05; p = .004) were significant. On univariate analysis, improved OS was associated with a lower N category (p = .048), greater hemoglobin levels (p <.001), and FGF-2 negativity (p <.001). On multivariate analysis of OS, greater hemoglobin levels (RR, 4.62; p = .002) and FGF-2 expression (RR, 3.25; p = .002) maintained significance.

CONCLUSIONS

Tumor cell expression of FGF-2 appeared to be an independent negative predictor of LRC, MFS, and OS.

Angiogenesis inhibitors: current strategies and future prospects

Angiogenesis has become an attractive target for drug therapy because of its key role in tumor growth. An extensive array of compounds is currently in preclinical development, with many now entering the clinic and/or achieving approval from the US Food and Drug Administration. Several regulatory and signaling molecules governing angiogenesis are of interest, including growth factors (eg, vascular endothelial growth factor, platelet-derived growth factor, fibroblast growth factor, and epidermal growth factor), receptor tyrosine kinases, and transcription factors such as hypoxia inducible factor, as well as molecules involved in mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) signaling. Pharmacologic agents have been identified that target these pathways, yet for some agents (notably thalidomide), an understanding of the specific mechanisms of antitumor action has proved elusive. The following review describes key molecular mechanisms and novel therapies that are on the horizon for antiangiogenic tumor therapy.

Fibroblast growth factor receptor 3-IIIc mediates colorectal cancer growth and migration

Background:

Deregulation of fibroblast growth factor receptor 3 (FGFR3) is involved in several malignancies. Its role in colorectal cancer has not been assessed before.

Methods:

Expression of FGFR3 in human colorectal tumour specimens was analysed using splice variant-specific real-time reverse transcriptase PCR assays. To analyse the impact of FGFR3-IIIc expression on tumour cell biology, colon cancer cell models overexpressing wild-type (WT-3b and WT3c) or dominant-negative FGFR3 variants (KD3c and KD3b) were generated by either plasmid transfection or adenoviral transduction.

Results:

Although FGFR3 mRNA expression is downregulated in colorectal cancer, alterations mainly affected the FGFR3-IIIb splice variant, resulting in an increased IIIc/IIIb ratio predominantly in a subgroup of advanced tumours. Overexpression of WT3c increased proliferation, survival and colony formation in all colon cancer cell models tested, whereas WT3b had little activity. In addition, it conferred sensitivity to autocrine FGF18-mediated growth and migration signals in SW480 cells with low endogenous FGFR3-IIIc expression. Disruption of FGFR3-IIIc-dependent signalling by dominant-negative FGFR3-IIIc or small interfering RNA-mediated FGFR3-IIIc knockdown resulted in inhibition of cell growth and induction of apoptosis, which could not be observed when FGFR3-IIIb was blocked. In addition, KD3c expression blocked colony formation and migration and distinctly attenuated tumour growth in SCID mouse xenograft models.

Conclusion:

Our data show that FGFR3-IIIc exerts oncogenic functions by mediating FGF18 effects in colorectal cancer and may constitute a promising new target for therapeutic interventions.

Expression of basic fibroblast growth factor, its receptors and syndecans in bladder cancer

Basic fibroblast growth factor (bFGF) is a heparin-binding cationic protein involved in a variety of pathological conditions including angiogenesis and solid tumour growth. The basic fibroblast growth factor receptor (FGFR) family comprises at least 4 high affinity tyrosine kinase receptors that require syndecans for their function. Mounting evidence indicates that syndecans, that bind both bFGF and their FGFRs, will act as stimulators, whereas syndecans that only bind bFGF will act as inhibitors of signaling by sequestering the growth factor. Recent findings have highlighted the importance of syndecans in urological cancers. The aim of this study is to investigate the expression of bFGF, its receptors (R1 and R2) and syndecans (1-4) in invasive urothelial carcinoma and normal-looking urothelium by Western blotting, RT-PCR, and immunohistochemistry analyses. Interestingly, bFGF, FGFR1 and FGFR2 protein levels statistically increased in bladder cancer tissues. mRNA of FGFR1 and syndecans (1-4), showed a statistically significant increase while an mRNA increase in the other molecules analysed was not significant. bFGF, its receptors and syndecan immunostaining were mainly present in the urothelium both in normal-looking tissues and urothelial neoplastic cells. In conclusion, our data report that the bFGF, FGFR and syndecan expressions are altered in bladder tumours.

The role of fibroblast growth factors in tumor growth

Biological processes that drive cell growth are exciting targets for cancer therapy. The fibroblast growth factor (FGF) signaling network plays a ubiquitous role in normal cell growth, survival, differentiation, and angiogenesis, but has also been implicated in tumor development. Elucidation of the roles and relationships within the diverse FGF family and of their links to tumor growth and progression will be critical in designing new drug therapies to target FGF receptor (FGFR) pathways. Recent studies have shown that FGF can act synergistically with vascular endothelial growth factor (VEGF) to amplify tumor angiogenesis, highlighting that targeting of both the FGF and VEGF pathways may be more efficient in suppressing tumor growth and angiogenesis than targeting either factor alone. In addition, through inducing tumor cell survival, FGF has the potential to overcome chemotherapy resistance highlighting that chemotherapy may be more effective when used in combination with FGF inhibitor therapy. Furthermore, FGFRs have variable activity in promoting angiogenesis, with the FGFR-1 subgroup being associated with tumor progression and the FGFR-2 subgroup being associated with either early tumor development or decreased tumor progression. This review highlights the growing knowledge of FGFs in tumor cell growth and survival, including an overview of FGF intracellular signaling pathways, the role of FGFs in angiogenesis, patterns of FGF and FGFR expression in various tumor types, and the role of FGFs in tumor progression.

Prognostic impact of fibroblast growth factor 2 in non-small cell lung cancer: coexpression with VEGFR-3 and PDGF-B predicts poor survival

PURPOSE

Fibroblast growth factor 2 (FGF2; basic fibroblast growth factor, b-FGF) and its main receptor FGFR-1 are important in both hemangiogenesis and lymphangiogenesis. Murine studies have indicated a close interplay between both FGF2 and platelet-derived growth factor-B (PDGF-B) as well as FGF2 and vascular endothelial growth factor-3 (VEGFR-3). This study investigates the prognostic impact of FGF2 and FGFR-1 in tumor cells and tumor stroma of resected non-small cell lung carcinomas (NSCLC) and explores the importance of their coexpression with VEGFR-3 or PDGF-B.

METHODS

Tumor tissue samples from 335 resected patients with stage I to IIIA NSCLC were obtained and tissue microarrays were constructed from duplicate cores of tumor cells and tumor-related stroma from each specimen. Immunohistochemistry was used to evaluate the expression of the molecular markers FGF2, FGFR-1, VEGFR-3, and PDGF-B.

RESULTS

In univariate analyses, high tumor cell FGF2 expression (p = 0.015) was a negative prognostic indicator for disease-specific survival. In tumor stroma, high FGF2 (p = 0.024) expression correlated with good prognosis. In multivariate analyses, high expression of FGF2 in tumor cells (p = 0.038) was an independent negative prognostic factor whereas increased FGF2 in stroma (p = 0.015) was a positive prognosticator. Tumor cell coexpressions of FGF2/VEGFR-3 (p < 0.001) and FGFR-1/PDGF-B (p = 0.002) were significant indicators of poor prognosis.

CONCLUSIONS

Expression of FGF2 in tumor cells is an independent negative prognostic factor, and the coexpressions of FGF2/VEGFR-3 and FGFR-1/PDGF-B are strongly associated with poor survival in NSCLC patients.

The fibroblast growth factor receptor signaling pathway as a mediator of intrinsic resistance to EGFR-specific tyrosine kinase inhibitors in non-small cell lung cancer

The EGFR has been targeted through the development of selective tyrosine kinase inhibitors (TKIs) that have proven effective in a subset of non-small cell lung cancer (NSCLC) patients, many bearing gain-of-function EGFR mutations or egfr gene amplification. However, the majority ( approximately 80-90%) of NSCLC patients do not respond to EGFR-specific TKIs and a high rate of acquired resistance to these therapeutics is observed in those that do respond. Thus, EGFR-specific TKIs will not, as single agents, make a high impact on overall lung cancer survival. A number of studies support the activities of other receptor tyrosine kinase pathways including cMet, IGF-1R and FGFRs as mechanisms for both intrinsic and acquired resistance to EGFR TKIs. While the role of cMet and IGF-1R signaling systems as mechanisms of resistance to EGFR TKIs has been widely reviewed in recent years, the potential role of FGFR-dependent signaling as a mechanism for EGFR TKI resistance has more recently emerged and will be highlighted herein. Due to the high degree of homology of FGFRs with VEGFRs and PDGFRs, FGFR-active TKIs already exist via development of VEGFR-targeted TKIs as angiogenesis inhibitors. Thus, these agents could be rapidly advanced into clinical investigations as FGFR inhibitors, either alone or in combination with TKIs selective for EGFR, cMet or IGF-1R as a means to expand the spectrum of NSCLC patients that can be effectively targeted with TKI-directed therapies.