Fibroblast Growth Factor/fibroblast Growth Factor Receptor Research Articles

FGFR Inhibitors in Cholangiocarcinoma—A Novel Yet Primary Approach: Where Do We Stand Now and Where to Head Next in Targeting This Axis?

Cholangiocarcinomas (CCAs) are rare but aggressive tumours with poor diagnosis and limited treatment options. Molecular targeted therapies became a promising proposal for patients after progression under first-line chemical treatment. In light of an escalating prevalence of CCA, it is crucial to fully comprehend its pathophysiology, aetiology, and possible targets in therapy. Such knowledge would play a pivotal role in searching for new therapeutic approaches concerning diseases' symptoms and their underlying causes. Growing evidence showed that fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) pathway dysregulation is involved in a variety of processes during embryonic development and homeostasis as well as tumorigenesis. CCA is known for its close correlation with the FGF/FGFR pathway and targeting this axis has been proposed in treatment guidelines. Bearing in mind the significance of molecular targeted therapies in different neoplasms, it seems most reasonable to move towards intensive research and testing on these in the case of CCA. However, there is still a need for more data covering this topic. Although positive results of many pre-clinical and clinical studies are discussed in this review, many difficulties lie ahead. Furthermore, this review presents up-to-date literature regarding the outcomes of the latest clinical data and discussion over future directions of FGFR-directed therapies in patients with CCA.

FGF-FGFR signaling promotes the development of invasive cervical cancer.

Cervical cancer is one of the most frequently diagnosed gynecological malignancies among women worldwide. The main cause of cervical cancer is the human papilloma virus (HPV). Mahmood et al. investigated in detail the role of the fibroblast growth factor (FGF)-FGF receptor (FGFR) signaling axis in the development of the invasive form of the disease. The presented work clearly indicates the FGFR signaling as an additional but important factor for the development of a highly malignant tumor. Comment on https://doi.org/10.1111/febs.16331.

Halting the FGF/FGFR axis leads to antitumor activity in Waldenström macroglobulinemia by silencing MYD88

The human fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) axis deregulation is largely involved in supporting the pathogenesis of hematologic malignancies, including Waldenström macroglobulinemia (WM). WM is still an incurable disease, and patients succumb because of disease progression. Therefore, novel therapeutics designed to specifically target deregulated signaling pathways in WM are required. We aimed to investigate the role of FGF/FGFR system blockade in WM by using a pan-FGF trap molecule (NSC12). Wide-transcriptome profiling confirmed inhibition of FGFR signaling in NSC12-treated WM cells; unveiling a significant inhibition of MYD88 was also confirmed at the protein level. Importantly, the NSC12-dependent silencing of MYD88 was functionally active, as it led to inhibition of MYD88-driven pathways, such as BTK and SYK, as well as the MYD88-downstream target HCK. Of note, both canonical and noncanonical NF-κB cascades were downregulated in WM cells upon NSC12 treatment. Functional sequelae exerted by NSC12 in WM cells were studied, demonstrating significant inhibition of WM cell growth, induction of WM cell apoptosis, halting MAPK, JAK/STAT3, and PI3K-Akt pathways. Importantly, NSC12 exerted an anti-WM effect even in the presence of bone marrow microenvironment, both in vitro and in vivo. Our studies provide the evidence for using NSC12 as a specific FGF/FGFR system inhibitor, thus representing a novel therapeutic strategy in WM.

FGF/FGFR Axis-Blockade Leads to Anti-Tumor Activity in Waldenstrom's Macroglobulinemia By Silencing MYD88

The human fibroblast growth factor/fibroblast growth factor-receptor (FGF/FGFR) axis deregulation is largely involved in supporting the pathogenesis of hematologic malignancies, including Waldenstrom's Macroglobulinemia (WM). Therefore, novel therapeutics designed to specifically target deregulated signaling pathways in WM are required. We investigated the role of FGF/FGFR system blockade in WM by using a pan-FGF trap molecule, NSC12, a small molecule identified using pharmacophore modeling of the interaction of a minimal PTX3-derived FGF-binding pentapeptide with FGF2. By interrogating the transcriptome signature of patients' BM-derived CD19-positive cells (GEO9656, GEO6691), we found a significant enrichment of FGF/FGFR-driven signaling cascades, including PI3K-AKT, MAPK and STAT3 pathways (FDR<0.25; P<0.05); coupled with higher expression of FGFs (FGF2, FGF7, FGF12, FGF18; P<0.05) in WM cells as compared to their normal cellular counterpart. FGFRs are also shown to be overexpressed in WM. We performed transcriptome profiling of NSC12-treated WM cells, confirming the blockade of the FGFR-signaling blockade; and, importantly, we discovered the efficacious silencing of MYD88 and MYD88-dopwnstream target HCK in WM cells. These findings were confirmed at protein level, showing inhibition of MYD88-driven pathways, such as BTK-, and SYK-phosphorylation. As a further demonstration of the functional impact of NSC12-dependent targeting of MYD88, we could confirm the inhibition of both canonical and non-canonical NF-kB in NSC12-treated WM cells, as assessed at nuclear protein level by WB and by using the NFkB activity assay. In addition, the NSC12-dependent inhibition of MYD88 resulted in silencing of the MAPK-ERK signaling cascade, thus leading to NSC12-induced Myc-silencing in WM cells. We next confirmed the efficacy of NSC12 in silencing bone marrow stromal cell (BMSC)-induced FGFR3 phosphorylation; paralleled by inhibition of of pro-survival pathways, including pAKT, the AKT-downstream pGSK3β; p-ERK; and p-STAT3. Functional sequelae of the FGF/FGFR blockade in WM cells were studied, demonstrating inhibition of WM cell growth, induction of apoptosis, enhanced ER stress and initiation of UPR. Of note, anti-WM activity of NSC12 was also documented using primary bone marrow-derived CD19+ cells isolated from patients with WM. In contrast, NSC12 did not show cytotoxicity on PBMC-derived CD19+ cells isolated from healthy donors. The anti-WM activity exerted by NSC12 was confirmed also within the context of the supportive bone marrow milieu, as shown both in vitro and in vivo. BCWM.1, MWCL1 cells were cultured with NSC12 in the presence or absence of primary WM BMSCs: adherence of WM cells to BMSCs triggered a significant increase in the proliferation, which was inhibited by NSC12in a dose-dependent manner (P<0.05). Using a disseminated humanized WM model, BCWM.1 M-Cherry-Luc tumor-bearing mice were treated with either NSC12 or vehicle control. NSC12-treated mice presented with a significant inhibition of WM tumor growth as demonstrated by bioluminescence imaging analysis. NSC12-dependent reduction of WM tumor cell BM infiltration was confirmed by IHC performed on harvested femurs, in comparison to vehicle-treated mice. Importantly, we assessed MYD88-mRNA expression using harvested bone marrow femurs; and found a significant reduction of MYD88- and MYD88-downstream target HCK in NSC12-treated mice was confirmed ex vivo (P<0.05). Overall, our studies are reporting on the use of NSC12, as a novel potential therapeutic strategy to specifically halt the FGF/FGFR axis in WM; and demonstrate how the observed anti-WM activity exerted by NSC12 may be driven, at least in part, by inhibition of MYD88. Disclosures Motta: Roche: Honoraria; Janssen: Honoraria. Rossi:Alexion: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: Advisory board; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Honoraria; Amgen: Honoraria; Sanofi: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees. Roccaro:Amgen: Other; AstraZeneca: Research Funding; Celgene: Other; Janssen: Other; Italian Association for Cancer Research (AIRC): Research Funding; Transcan2-ERANET: Research Funding; European Hematology Association: Research Funding.

The FGF/FGFR System in Breast Cancer: Oncogenic Features and Therapeutic Perspectives.

Simple SummaryThe fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) system represents an emerging therapeutic target in breast cancer. Here, we discussed previous studies dealing with FGFR molecular aberrations, the alterations in the FGF/FGFR signaling across the different subtypes of breast cancer, the functional interplay between the FGF/FGFR axis and important components of the breast microenvironment, the therapeutic usefulness of FGF/FGFR inhibitors for the treatment of breast cancer.One of the major challenges in the treatment of breast cancer is the heterogeneous nature of the disease. With multiple subtypes of breast cancer identified, there is an unmet clinical need for the development of therapies particularly for the less tractable subtypes. Several transduction mechanisms are involved in the progression of breast cancer, therefore making the assessment of the molecular landscape that characterizes each patient intricate. Over the last decade, numerous studies have focused on the development of tyrosine kinase inhibitors (TKIs) to target the main pathways dysregulated in breast cancer, however their effectiveness is often limited either by resistance to treatments or the appearance of adverse effects. In this context, the fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) system represents an emerging transduction pathway and therapeutic target to be fully investigated among the diverse anti-cancer settings in breast cancer. Here, we have recapitulated previous studies dealing with FGFR molecular aberrations, such as the gene amplification, point mutations, and chromosomal translocations that occur in breast cancer. Furthermore, alterations in the FGF/FGFR signaling across the different subtypes of breast cancer have been described. Next, we discussed the functional interplay between the FGF/FGFR axis and important components of the breast tumor microenvironment. Lastly, we pointed out the therapeutic usefulness of FGF/FGFR inhibitors, as revealed by preclinical and clinical models of breast cancer.

Genomic landscape of FGF/FGFR pathway alternations across 12,372 pan-cancer patients.

e13503 Background: The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling pathway is involved in diverse biological processes and plays a crucial role in carcinogenesis. FGFR targeted therapies have shown great promise in the treatment of a multitude of malignancies. This study aimed to assess the alternations of FGF/FGFR pathway and explore the potential relationships between the genetic alternations in a pan-cancer setting. Methods: Next-generation sequencing was conducted with formalin-fixed, paraffin-embedded tumor specimens from 12,372 Chinese cancer patients with over 21 tumor types, including lung cancer (n = 3557), liver cancer (n = 1433), colorectal cancer (n = 1310), biliary tract cancer (n = 960), gastric cancer (n = 758), etc. Somatic mutations including single nucleotide variations (SNVs), amplifications, and fusions were analyzed, and microsatellite instability status was also assayed. Results: Of all patients, the frequency of genomic alterations in FGF/FGFR pathway (FGF3/4/6/10/14/19/23 and FGFR1-4) ranged from 54.1% (86/159) in esophagus cancer, 40.7% (112/275) in bladder/urinary tract cancer, 28.4% (73/257) in head and neck cancer to 5.3% (5/95) in prostate cancer and 4.0% (22/548) in kidney cancer. Amongst all, the highest mutational prevalence fell in FGFR SNV (5.13%) and FGF amplification (5.08%), followed by FGF SNV (3.90%), FGFR amplification (2.89%), FGFR fusion (0.88%), and FGF fusion (0.06%). Partial co-occurrence was observed between alternations of FGFR1 and 11q13 (FGF3/4/19) and between FGF6 and FGF23. On the other side, alternations of FGFR1, FGFR2, FGFR3, and FGFR4 were found to be mutually exclusive ( p< 0.001). In addition, microsatellite instability was found to be positively correlated with FGF/FGFR pathway mutation ( p< 0.001), while was negatively correlated with pathway amplifications ( p= 0.002). Conclusions: Our study investigated the molecular landscape of FGF/FGFR pathway alternations and the interplay between co-occurrence and mutual exclusivity between pathway genes in a large pan-cancer cohort. FGF/FGFR pathway mutations occurs in a variety of solid tumors, indicating that these patients may benefit from FGFR inhibitors.

Targeting the FGFR signaling pathway in cholangiocarcinoma: promise or delusion?

Cholangiocarcinoma (CCA) is a refractory cancer with limited treatment options and poorly understood molecular mechanisms underlying tumor development. The most effective treatment is surgical resection; however, patients are highly prone to recurrence. Moreover, considering that most patients are diagnosed in advanced stages, treatment options are restricted to palliative care, which results in poor prognosis. Due to the limited effect of chemotherapy and radiotherapy, targeted therapy is becoming a hot topic in the field of biliary cancer treatment. The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling pathway involves a variety of key biological processes for cell survival, differentiation, and metabolism. Next-generation sequencing data mining has shown that high levels of FGF/FGFR expression are associated with reduced overall survival (OS) in CAA, which indicates that the FGF/FGFR pathway may be an effective target for CAA treatment. This paper reviews the effect of FGF/FGFR signaling on CCA from onset to treatment and highlights the promise of FGF/FGFR signaling pathway inhibitors for targeting CCA.

Long Pentraxin-3 Follows and Modulates Bladder Cancer Progression.

Bladder tumors are a diffuse type of cancer. Long pentraxin-3 (PTX3) is a component of the innate immunity with pleiotropic functions in the regulation of immune response, tissue remodeling, and cancer progression. PTX3 may act as an oncosuppressor in different contexts, functioning as an antagonist of the fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) system, rewiring the immune microenvironment, or acting through mechanisms not yet fully clarified. In this study we used biopsies and data mining to assess that PTX3 is differentially expressed during the different stages of bladder cancer (BC) progression. BC cell lines, representative of different tumor grades, and transgenic/carcinogen-induced models were used to demonstrate in vitro and in vivo that PTX3 production by tumor cells decreases along the progression from low-grade to high-grade advanced muscle invasive forms (MIBC). In vitro and in vivo data revealed for the first time that PTX3 modulation and the consequent impairment of FGF/FGR systems in BC cells have a significant impact on different biological features of BC growth, including cell proliferation, motility, metabolism, stemness, and drug resistance. PTX3 exerts an oncosuppressive effect on BC progression and may represent a potential functional biomarker in BC evolution. Moreover, FGF/FGFR blockade has an impact on drug resistance and stemness features in BC.

Fibroblast growth factor modulates mast cell recruitment in a murine model of prostate cancer.

Mast cells are important modifiers of prostate tumor microenvironment. The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) system plays a non-redundant autocrine/paracrine role in the growth, vascularization and progression of prostate tumors. Accordingly, the FGF antagonist long pentraxin-3 (PTX3) and the PTX3-derived small molecule FGF-trap NSC12 have been shown to inhibit the growth and vascularization of different FGF-dependent tumor types, including prostate cancer. In this study, we show that recombinant FGF2 is able to cause mast cell recruitment in vivo in the Matrigel plug assay. Conversely, PTX3 overexpression in transgenic mice or treatment with the FGF inhibitor NSC12 result in a significant inhibition of the growth and vascularization of TRAMP-C2 tumor grafts, a murine model of prostate cancer, that were paralleled by a decrease of mast cell infiltrate into the lesion. These data confirm and extend previous observations about the capacity of mast cells to respond chemotactically to FGF2 stimulation and provide evidence about a relationship among mast cell recruitment, angiogenesis, and tumor growth in human prostate adenocarcinoma.

Sp3 controls fibroblast growth factor receptor 4 gene activity during myogenic differentiation

Fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling is a critical component in the regulation of myoblast proliferation and differentiation. The transient FGFR4 gene expression during the transition from proliferating myoblasts to differentiated myotubes indicates that FGFR4 regulates this critical phase of myogenesis. The Specificity Protein (SP) family of transcription factors controls FGFR family member gene activity. We sought to determine if members of the Sp family regulate mouse FGFR4 gene activity during myogenic differentiation. RT-PCR and western blot analysis of FGFR4 mRNA and protein revealed transient expression over 72h, with peak expression between 24 and 36h after addition of differentiation medium to C2C12 myogenic cultures. Sp3 also displayed a transient expression pattern with peak expression occurring after 6h of differentiation. We cloned a 1527bp fragment of the mouse FGFR4 promoter into a luciferase reporter. This FGFR4 promoter contains eight putative Sp binding sites and directed luciferase gene activity comparable to native FGFR4 expression. Overexpression of Sp1 and Sp3 showed that Sp1 repressed FGFR4 gene activity, and Sp3 activated FGFR4 gene activity during myogenic differentiation. Mutational analyses of multiple Sp binding sites within the FGFR4 promoter revealed that three of these sites were transcriptionally active. Electromobility shift assays and chromatin immunoprecipitation of the area containing the activator sites showed that Sp3 bound to this promoter location.

Inhibition of the fibroblast growth factor receptor (FGFR) pathway: the current landscape and barriers to clinical application.

The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) is a tyrosine kinase signaling pathway that has a fundamental role in many biologic processes including embryonic development, tissue regeneration, and angiogenesis. Increasing evidence indicates that this pathway plays a critical role in oncogenesis via gene amplification, activating mutations, or translocation in tumors of various histologies. With multiplex sequencing technology, the detection of FGFR aberrations has become more common and is tied to cancer cell proliferation, resistance to anticancer therapies, and neoangiogenesis. Inhibition of FGFR signaling appears promising in preclinical studies, suggesting a pathway of clinical interest in the development of targeted therapy. Phase I trials have demonstrated a manageable toxicity profile. Currently, there are multiple FGFR inhibitors under study with many non-selective (multi-kinase) inhibitors demonstrating limited clinical responses. As we progress from the first generation of non-selective drugs to the second generation of selective FGFR inhibitors, it is clear that FGFR aberrations do not behave uniformly across cancer types; thus, a deeper understanding of biomarker strategies is undoubtedly warranted. This review aims to consolidate data from recent clinical trials with a focus on selective FGFR inhibitors. As Phase II clinical trials emerge, concentration on patient selection as it pertains to predicting response to therapy, feasible methods for overcoming toxicity, and the likelihood of combination therapies should be utilized. We will also discuss qualities that may be desirable in future generations of FGFR inhibitors, with the hope that overcoming these current barriers will expedite the availability of this novel class of medications.

Combinatorial Pharmacophore-Based 3D-QSAR Analysis and Virtual Screening of FGFR1 Inhibitors.

The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling pathway plays crucial roles in cell proliferation, angiogenesis, migration, and survival. Aberration in FGFRs correlates with several malignancies and disorders. FGFRs have proved to be attractive targets for therapeutic intervention in cancer, and it is of high interest to find FGFR inhibitors with novel scaffolds. In this study, a combinatorial three-dimensional quantitative structure-activity relationship (3D-QSAR) model was developed based on previously reported FGFR1 inhibitors with diverse structural skeletons. This model was evaluated for its prediction performance on a diverse test set containing 232 FGFR inhibitors, and it yielded a SD value of 0.75 pIC50 units from measured inhibition affinities and a Pearson’s correlation coefficient R2 of 0.53. This result suggests that the combinatorial 3D-QSAR model could be used to search for new FGFR1 hit structures and predict their potential activity. To further evaluate the performance of the model, a decoy set validation was used to measure the efficiency of the model by calculating EF (enrichment factor). Based on the combinatorial pharmacophore model, a virtual screening against SPECS database was performed. Nineteen novel active compounds were successfully identified, which provide new chemical starting points for further structural optimization of FGFR1 inhibitors.

Careless talk costs lives: fibroblast growth factor receptor signalling and the consequences of pathway malfunction.

Since its discovery 40 years ago, fibroblast growth factor (FGF) receptor (FGFR) signalling has been found to regulate fundamental cellular behaviours in a wide range of cell types. FGFRs regulate development, homeostasis, and repair and are implicated in many disorders and diseases; and indeed, there is extensive potential for severe consequences, be they developmental, homeostatic, or oncogenic, should FGF-FGFR signalling go awry, so careful control of the pathway is critically important. In this review, we discuss the recent developments in the FGF field, highlighting how FGFR signalling works in normal cells, how it can go wrong, how frequently it is compromised, and how it is being targeted therapeutically.

Abstract 2839: Antitumor activities of FGFR inhibitors in FGFR1-overexpressing hepatocellular carcinoma patient-derived xenograft tumor models

Abstract Hepatocellular carcinoma (HCC) is intrinsically resistant to conventional chemotherapies. Developing effective therapeutics becomes critical to tackle the unmet medical need. The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling axis plays an important role in liver development and homeostasis in adults. Deregulation of the FGF/FGFR signaling pathway through genetic modification or overexpression of the receptors (or their ligands) has been increasingly recognized in HCC. Accordingly, therapeutic intervention of the pathway has been extensively explored. In this study, analysis of a panel of patient-derived xenograft (PDX) HCC models by Affymetrix human gene expression arrays revealed overexpression of FGFR1 in 13 out of 43 (30%) models. Antitumor activities of FGFR inhibitors, including lenvatinib, dovitinib, ENMD-2076, and LY2874455, were then tested in five models. Lenvatinib exhibited the most potent activity in all models, whereas LY2874455 failed to show the effect in one of models. IC50s for FGFR1 inhibition of ENMD-2076, lenvatinib, dovitinib and LY2874455 were 145 nM, 134.5 nM, 53.5 nM and 0.6 nM, respectively. In SNU-16 and NCI-H520 cell lines, IC50s of dovitinib, lenvatinib, ENMD-2076, and LY2874455 were 76/1355 nM, 94/4770 nM, 306/2280 nM, and 0.3/664 nM, respectively. Furthermore, analyses of PDX tissues by Affymetrix SNP Array 6.0 arrays revealed no amplification of FGFR1/2 genes in four models except for amplifications of FGFR3 gene in two models. Whole exome sequencing did not detect nonsynonymous genetic alterations, including SNPs and indels, in FGFR1/2 genes in these xenografts except for a few genetic variations in FGFR3/4 genes. Overall, due to the multi-targeting mechanisms of these inhibitors, in vitro inhibitory effects of the compounds on FGFR1 enzyme and cell proliferation may not correlate with the in vivo anti-tumor activities. Overexpression of FGFR1 gene may serve as a predictive biomarker for therapeutic intervention of the FGF/FGFR pathway in HCC by using lenvatinib, dovitinib and ENMD-2076. Further studies are required to define additional biomarkers for LY2874455. Thus, our findings provide the rationale for the clinical development of FGFR inhibitors in a subset of HCC patients expressing a high level of FGFR1 gene. Citation Format: Douglas D. Fang, Bin Zhang, Weiguo Xu, Kang Yan, Qingyang Gu, Qiang Xu, Yexiong Tan, Hongye Sun, Qin Luo, Weifeng Mao, Chiho Li, Jiangpeng Liao, Guibai Liang, Shu-Hui Chen, Chi-Chung Chan. Antitumor activities of FGFR inhibitors in FGFR1-overexpressing hepatocellular carcinoma patient-derived xenograft tumor models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2839. doi:10.1158/1538-7445.AM2014-2839

Genetic Variants in the Fibroblast Growth Factor Pathway as Potential Markers of Ovarian Cancer Risk, Therapeutic Response, and Clinical Outcome

The fibroblast growth factor (FGF) and FGF receptor (FGFR) axis plays a critical role in tumorigenesis, but little is known of its influence in ovarian cancer. We sought to determine the association of genetic variants in the FGF pathway with risk, therapeutic response, and survival of patients with ovarian cancer. We matched 339 non-Hispanic white ovarian cancer cases with 349 healthy controls and genotyped them for 183 single-nucleotide polymorphisms (SNPs) from 24 FGF (fibroblast growth factor) and FGFR (fibroblast growth factor receptor) genes. Genetic associations for the main effect, gene-gene interactions, and the cumulative effect were determined. Multiple SNPs in the FGF-FGFR axis were associated with an increased risk of ovarian cancer. In particular, FGF1 [fibroblast growth factor 1 (acidic)] SNP rs7727832 showed the most significant association with ovarian cancer (odds ratio, 2.27; 95% CI, 1.31-3.95). Ten SNPs were associated with a reduced risk of ovarian cancer. FGF18 (fibroblast growth factor 18) SNP rs3806929, FGF7 (fibroblast growth factor 7) SNP rs9920722, FGF23 (fibroblast growth factor 23) SNP rs12812339, and FGF5 (fibroblast growth factor 5) SNP rs3733336 were significantly associated with a favorable treatment response, with a reduction of risk of nonresponse of 40% to 60%. Eleven SNPs were significantly associated with overall survival. Of these SNPs, FGF23 rs7961824 was the most significantly associated with improved prognosis (hazard ratio, 0.55; 95% CI, 0.39-0.78) and was associated with significantly longer survival durations, compared with individuals with the common genotype at this locus (58.1 months vs. 38.0 months, P = 0.005). Survival tree analysis revealed FGF2 rs167428 as the primary factor contributing to overall survival. Significant associations of genetic variants in the FGF pathway were associated with ovarian cancer risk, therapeutic response, and survival. The discovery of multiple SNPs in the FGF-FGFR pathway provides a molecular approach for risk assessment, monitoring therapeutic response, and prognosis.

FGF–FGFR Signaling Mediated through Glycosaminoglycans in Microtiter Plate and Cell-Based Microarray Platforms

Fibroblast growth factor (FGF) signals cell growth through its interaction with a fibroblast growth factor receptor (FGFR) and a glycosaminoglycn (GAG) coreceptor. Here, we examine the signaling of five different FGFs (1, 2, 6, 8, and 8b) through FGFR3c. A small library of GAG and GAG-derivative coreceptors are screened to understand better the structure-activity relationship of these coreceptors on signaling. Initially, data were collected in a microtiter plate well-based cell proliferation assay. In an effort to reduce reagent requirements and improve assay throughput, a cell-based microarray platform was developed. In this cell-based microarray, FGFR3c-expressing cells were printed in alginate hydrogel droplets of ∼30 nL and incubated with FGF and GAG. Heparin was the most effective GAG coreceptor for all FGFs studied. Other GAGs, such as 2-O-desulfated heparin and chondroitin sulfate B, were also effective coreceptors. Signaling by FGF 8 and FGF 8b showed the widest tolerance for coreceptor structure. Finally, this on-chip cell-based microarray provides comparable data to a microtiter plate well-based assay, demonstrating that the coreceptor assay can be converted into a high-throughput assay.

Fibroblast Growth Factor Receptor Inhibitors as a Cancer Treatment: From a Biologic Rationale to Medical Perspectives

The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling pathway plays a fundamental role in many physiologic processes, including embryogenesis, adult tissue homeostasis, and wound healing, by orchestrating angiogenesis. Ligand-independent and ligand-dependent activation have been implicated in a broad range of human malignancies and promote cancer progression in tumors driven by FGF/FGFR oncogenic mutations or amplifications, tumor neoangiogenesis, and targeted treatment resistance, thereby supporting a strong rationale for anti-FGF/FGFR agent development. Efforts are being pursued to develop selective approaches for use against this pathway by optimizing the management of emerging, class-specific toxicity profiles and correctly designing clinical trials to address these different issues.

Abstract 854: Patient stratification strategies for NVP-BGJ398, a selective pan-FGFR inhibitor in phase I clinical trials

Abstract The mammalian fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) family comprises 22 FGF ligands, which exert their action through 4 highly conserved transmembrane tyrosine kinase receptors (FGFR1, FGFR2, FGFR3 and FGFR4). This highly complex signaling network regulates fundamental developmental pathways and physiological processes in the adult organism. A growing body of evidence linking deregulation of the FGF/FGFR system, as a consequence of genetic alterations, to the pathogenesis of cancer makes these receptors attractive targets for therapeutic intervention. To this purpose we have developed NVP-BGJ398, an orally bioavailable, selective pan-FGFR kinase inhibitor which is currently in clinical Phase I dose escalation trial. In order to preclinically identify and validate patient stratification biomarkers that accurately predict for response to NVP-BGJ398 in the clinic, we have utilized the Cancer Cell Line Encyclopedia (CCLE). The CCLE is a collection of almost 1000 cancer cell lines representing multiple tumor types that, in a collaborative effort between The Novartis Institutes for BioMedical Research and the Broad Institute, has been comprehensively annotated in terms of genome-scale mRNA expression, gene copy number alterations and gene mutations (http:/www.broadinstitute.org/ccle). In addition, over half of these cell lines were subjected to high-throughput cell viability assays in the presence NVP-BGJ398, with the aim of generating cell line sensitivity data. Here we show the validation of predictive biomarkers of response in primary human tumor xenografts, revealed through the analysis of the CCLE, as well as the identification of potentially new indications for NVP-BGJ398. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 854. doi:1538-7445.AM2012-854

Molecular Pathways: Fibroblast Growth Factor Signaling: A New Therapeutic Opportunity in Cancer

The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling axis plays an important role in normal organ, vascular, and skeletal development. Deregulation of FGFR signaling through genetic modification or overexpression of the receptors (or their ligands) has been observed in numerous tumor settings, whereas the FGF/FGFR axis also plays a key role in driving tumor angiogenesis. A growing body of preclinical data shows that inhibition of FGFR signaling can result in antiproliferative and/or proapoptotic effects, both in vitro and in vivo, thus confirming the validity of the FGF/FGFR axis as a potential therapeutic target. In the past, development of therapeutic approaches to target this axis has been hampered by our inability to develop FGFR-selective agents. With the advent of a number of new modalities for selectively inhibiting FGF/FGFR signaling, we are now in a unique position to test and validate clinically the many hypotheses that have been generated preclinically.

Abstract B246: NVP-BGJ398: A potent and selective inhibitor of the fibroblast growth factor receptor family.

Abstract The mammalian fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) family comprises 22 FGF ligands, 18 of which exert their action through 4 highly conserved transmembrane tyrosine kinase receptors (FGFR1, FGFR2, FGFR3 and FGFR4). This highly complex signaling network regulates fundamental developmental pathways, physiological processes in the adult organism and a variety of cellular functions including proliferation, differentiation, and survival. Owing to such prominent roles, it is not surprising that different types of FGF/FGFR alterations, such as abnormal expression, mutations, and amplifications, have been found in diverse tumor types. A growing body of evidence linking deregulation of the FGF/FGFR system to the pathogenesis of cancer makes these receptors attractive targets for therapeutic intervention by a small molecular weight inhibitor approach. We have established a new and non-conventional strategy to mimic documented lead compounds which consists in the replacement of real rings by stable pseudo six-membered rings resulting from the formation of an intramolecular hydrogen bond in a planar conjugated system. More recently, we have reported an example of the application of such strategy to the design of a new class of protein kinase inhibitors featuring a N-pyrimidin-4-yl-urea motif as an alternative to the pyrido[2,3-d]pyrimidin-7-one core structure of a well-known class of protein kinase inhibitors. In this context, we have described a prototype compound displaying submicromolar activity against several tyrosine kinases including FGFR1. In this communication we illustrate the process, guided by the use of molecular modeling and biochemical and cellular assays, that led to the identification of NVP-BGJ398, a potent and selective FGFR antagonist currently in phase I clinical trial. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B246.