The fibroblast growth factor receptor-4 Arg388 allele is associated with prostate cancer initiation and progression

Potential role of genetic polymorphisms in neoadjuvant chemotherapy response in breast cancer

Chemoresistance leads to treatment failure, which can arise through different mechanisms including patients' characteristics. Searching for genetic profiles as a predictor for drug response and toxicity has been extensively studied in pharmacogenomics, thus contributing to personalized medicine and providing alternative treatments. Numerous studies have demonstrated significant evidence of association between genetic polymorphisms and response to neoadjuvant chemotherapy (NAC) in breast cancer. In this review, we explored the potential impact of genetic polymorphisms in NAC primary resistance through selecting a specific clinical profile. The genetic variability within pharmacokinetics, pharmacodynamics, DNA synthesis and repair, and oncogenic signaling pathways genes could be predictive or prognostic markers for NAC resistance. The clinical implication of these results can help provide individualized treatment plans in the early stages of breast cancer treatment. Further studies are needed to determine the genetic hosts of primary chemoresistance mechanisms in order to further emphasize the implementation of genotypic approaches in personalized medicine.

Single Nucleotide Polymorphisms Associated with Prostate Cancer Progression: A Systematic Review

BACKGROUND

New biomarkers of progression in patients with prostate cancer (PCa) are needed to improve their classification and clinical management. This systematic review investigated the relationship between single nucleotide polymorphisms (SNPs) and PCa progression.

METHODS

A keyword search was performed in Pubmed, EMBASE, Scopus, Web of Science, and Cochrane for publications between 2007 and 2022. We included articles with adjusted and significant associations, a median follow-up greater than or equal to 24 months, patients taken to radical prostatectomy (RP) as a first therapeutic option, and results presented based on biochemical recurrence (BCR).

RESULTS

In the 27 articles selected, 73 SNPs were identified in 39 genes, organized in seven functional groups. Of these, 50 and 23 SNPs were significantly associated with a higher and lower risk of PCa progression, respectively. Likewise, four haplotypes were found to have a significant association with PCa progression.

CONCLUSION

This article highlights the importance of SNPs as potential markers of PCa progression and their possible functional relationship with some genes relevant to its development and progression. However, most variants were identified only in cohorts from two countries; no additional studies reproduce these findings.

Receptor tyrosine kinases: biological functions and anticancer targeted therapy

Receptor tyrosine kinases (RTKs) are a class of protein kinases that play crucial roles in various cellular processes, including cell migration, morphological differentiation, cell growth, and angiogenesis. In humans, 58 RTKs have been identified and categorized into 20 distinct families based on the composition of their extracellular regions. RTKs are primarily activated by specific ligands that bind to their extracellular region. They not only regulate tumor transformation, proliferation, metastasis, drug resistance, and angiogenesis, but also initiate and maintain the self-renewal and cloning ability of cancer stem cells. Accurate diagnosis and grading of tumors with dysregulated RTKs are essential in clinical practice. There is a growing body of evidence supporting the benefits of RTKs-targeted therapies for cancer patients, and researchers are actively exploring new targets and developing targeted agents. However, further optimization of RTK inhibitors is necessary to effectively target the diverse RTK alterations observed in human cancers. This review provides insights into the classification, structure, activation mechanisms, and expression of RTKs in tumors. It also highlights the research advances in RTKs targeted anticancer therapy and emphasizes their significance in optimizing cancer diagnosis and treatment strategies.

Engineered Phage-Based Cancer Vaccines: Current Advances and Future Directions

Bacteriophages have emerged as versatile tools in the field of bioengineering, with enormous potential in tissue engineering, vaccine development, and immunotherapy. The genetic makeup of phages can be harnessed for the development of novel DNA vaccines and antigen display systems, as they can provide a highly organized and repetitive presentation of antigens to immune cells. Bacteriophages have opened new possibilities for the targeting of specific molecular determinants of cancer cells. Phages can be used as anticancer agents and carriers of imaging molecules and therapeutics. In this review, we explored the role of bacteriophages and bacteriophage engineering in targeted cancer therapy. The question of how the engineered bacteriophages can interact with the biological and immunological systems is emphasized to comprehend the underlying mechanism of phage use in cancer immunotherapy. The effectiveness of phage display technology in identifying high-affinity ligands for substrates, such as cancer cells and tumor-associated molecules, and the emerging field of phage engineering and its potential in the development of effective cancer treatments are discussed. We also highlight phage usage in clinical trials as well as the related patents. This review provides a new insight into engineered phage-based cancer vaccines.

Mutational landscape of primary breast angiosarcoma with repeated resection and recurrence over a 15-year period: A case report

Angiosarcoma is a rare malignant tumor derived from vascular endothelial cells and has a poor prognosis. We have experienced a case of multiple breast angiosarcoma for which multiple resections had been performed during the course of its progression over a period of more than 15 years, allowing comprehensive genetic mutation analysis. Somatic mutations in several cancer-related genes were detected, but no previously reported driver gene mutations of angiosarcoma were evident. Several germline mutations associated with malignancy, such as single nucleotide polymorphisms in Fibroblast Growth Factor Receptor 4 (FGFR4) (p.Gly388Arg, rs351855), Kinase Insert Domain Receptor (KDR) (Gln472His, rs1870377) and tumor protein p53 (TP53) (p.Pro72Arg, rs1042522) were detected. Common signatures and genetic mutations were scarce in the tumor samples subjected to genetic mutational analysis. These findings suggested that this case was very probably a multiprimary angiosarcoma.

FGFR4 Gly388Arg Polymorphism Reveals a Poor Prognosis, Especially in Asian Cancer Patients: A Meta-Analysis

The fibroblast growth factor-4 receptor (FGFR4) is a member of receptor tyrosine kinase. The FGFR4 Gly388Arg polymorphism in the transmembrane domain of the receptor has been shown to increase genetic susceptibility to cancers. However, its prognostic impact in cancer patients still remains controversial. Herein, we performed this meta-analysis to evaluate the clinicopathological and prognostic impacts of the FGFR4 Gly388Arg polymorphism in patients with cancer. We carried out a computerized extensive search using PubMed, Medline, and Ovid Medline databases up to July 2021. From 44 studies, 11,574 patients were included in the current meta-analysis. Regardless of the genetic models, there was no significant correlation of the FGFR4 Gly388Arg polymorphism with disease stage 3/4. In the homozygous model (Arg/Arg vs. Gly/Gly), the Arg/Arg genotype tended to show higher rate of lymph node metastasis compared with the Gly/Gly genotype (odds ratio = 1.21, 95% confidence interval (CI): 0.99-1.49, p = 0.06). Compared to patients with the Arg/Gly or Arg/Arg genotype, those with the Gly/Gly genotype had significantly better overall survival (hazard ratios (HR) = 1.19, 95% CI: 1.05-1.35, p = 0.006) and disease-free survival (HR = 1.25, 95% CI: 1.03-1.53, p = 0.02). In conclusion, this meta-analysis showed that the FGFR4 Gly388Arg polymorphism was significantly associated with worse prognosis in cancer patients. Our results suggest that this polymorphism may be a valuable genetic marker to identify patients at higher risk of recurrence or mortality.

Impact of FGFR4 Gene Polymorphism on the Progression of Colorectal Cancer

Colorectal cancer (CRC) is a multifactorial malignancy, and its high incidence and mortality rate remain a global public health burden. Fibroblast growth factor receptor 4 (FGFR4) is a receptor tyrosine kinase that has been shown to play a key role in cancer development and prognosis via the activation of its downstream oncogenic signaling pathways. The present study aimed to explore the impact of FGFR4 gene polymorphisms on the risk and progression of CRC. Three FGFR4 single-nucleotide polymorphisms (SNPs), including rs1966265, rs351855, and rs7708357, were evaluated in 413 CRC cases and 413 gender- and age-matched cancer-free controls. We did not observe any significant association of three individual SNPs with the risk of CRC between the case and control group. However, while assessing the clinicopathological parameters, patients of rectal cancer possessing at least one minor allele of rs1966265 (AG and GG; AOR, 0.236; p = 0.046) or rs351855 (GA and AA; AOR, 0.191; p = 0.022) were found to develop less metastasis as compared to those who are homozygous for the major allele. Further analyses using the datasets from the Genotype-Tissue Expression (GTEx) Portal and The Cancer Genome Atlas (TCGA) revealed that rs351855 regulated FGFR4 expression in many human tissues, and increased FGFR4 levels were associated with the occurrence, advanced stage, and distal metastasis of colon adenocarcinoma. These data suggest that the amino acid change in combination with altered expression levels of FGFR4 due to genetic polymorphisms may affect CRC progression.

Phage-Displayed Peptides for Targeting Tyrosine Kinase Membrane Receptors in Cancer Therapy

Receptor tyrosine kinases (RTKs) regulate critical physiological processes, such as cell growth, survival, motility, and metabolism. Abnormal activation of RTKs and relative downstream signaling is implicated in cancer pathogenesis. Phage display allows the rapid selection of peptide ligands of membrane receptors. These peptides can target in vitro and in vivo tumor cells and represent a novel therapeutic approach for cancer therapy. Further, they are more convenient compared to antibodies, being less expensive and non-immunogenic. In this review, we describe the state-of-the-art of phage display for development of peptide ligands of tyrosine kinase membrane receptors and discuss their potential applications for tumor-targeted therapy.

An updated meta-analysis of the association between fibroblast growth factor receptor 4 polymorphisms and susceptibility to cancer

Fibroblast growth factor receptor 4 (FGFR4) is a cell surface receptor tyrosine kinases (RTKs) for FGFs.

Several studies have focused on the association between FGFR4 polymorphisms and cancer development. This meta-analysis aimed to estimate the association between FGFR4 rs351855 (Gly³⁸⁸Arg), rs1966265 (Val¹⁰Ile), rs7708357, rs2011077, and rs376618 polymorphisms and cancer risk. Eligible studies were identified from electronic databases. All statistical analyses were achieved with the STATA 14.0 software. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to quantitatively estimate the association. Overall, no significant association was found among rs351855, rs2011077, and rs376618 polymorphisms with the risk of overall cancer. The rs1966265 polymorphism significantly decreased the risk of cancer in recessive (OR = 0.87, 95% CI = 0.78–0.97, P=0.009, TT vs CT+CC) genetic model. Whereas the rs7708357 polymorphism was positively associated with cancer risk in dominant (OR = 1.17, 95% CI = 1.02–1.36, P=0.028) genetic model. Stratified analysis revealed that rs351855 variant significantly increased the risk of prostate cancer in heterozygous (OR = 1.16, 95% CI = 1.02–1.32, P=0.025 AG vs GG), dominant (OR = 1.20, 95% CI = 1.06–1.35, P=0.004, AG+AA vs GG), and allele (OR = 1.22, 95% CI = 1.06–1.41, P=0.005, A vs G) genetic models.

In summary, the findings of this meta-analysis indicate that rs1966265, rs7708357, and rs351855 polymorphisms are correlated to cancer development. Further well-designed studies are necessary to draw more precise conclusions.

FGFR4 regulates tumor subtype differentiation in luminal breast cancer and metastatic disease

Mechanisms driving tumor progression from less aggressive subtypes to more aggressive states represent key targets for therapy. We identified a subset of luminal A primary breast tumors that give rise to HER2-enriched (HER2E) subtype metastases, but remain clinically HER2 negative (cHER2-). By testing the unique genetic and transcriptomic features of these cases, we developed the hypothesis that FGFR4 likely participates in this subtype switching. To evaluate this, we developed 2 FGFR4 genomic signatures using a patient-derived xenograft (PDX) model treated with an FGFR4 inhibitor, which inhibited PDX growth in vivo. Bulk tumor gene expression analysis and single-cell RNA sequencing demonstrated that the inhibition of FGFR4 signaling caused molecular switching. In the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) breast cancer cohort, FGFR4-induced and FGFR4-repressed signatures each predicted overall survival. Additionally, the FGFR4-induced signature was an independent prognostic factor beyond subtype and stage. Supervised analysis of 77 primary tumors with paired metastases revealed that the FGFR4-induced signature was significantly higher in luminal/ER+ tumor metastases compared with their primaries. Finally, multivariate analysis demonstrated that the FGFR4-induced signature also predicted site-specific metastasis for lung, liver, and brain, but not for bone or lymph nodes. These data identify a link between FGFR4-regulated genes and metastasis, suggesting treatment options for FGFR4-positive patients, whose high expression is not caused by mutation or amplification.

Effects of FGFR4 G388R, V10I polymorphisms on the likelihood of cancer

The correlation between G388R or V10I polymorphisms of fibroblast growth factor receptor (FGFR) 4 gene and the risk of carcinoma has been investigated previously, but the results are contradictory. Odds ratios (ORs) with 95% confidence intervals (95%CIs), in silico tools, and immunohistochemical staining (IHS) were adopted to assess the association. In total, 13,793 cancer patients and 16,179 controls were evaluated in our pooled analysis. Summarization of all the studies showed that G388R polymorphism is associated with elevated susceptibility to cancer under homozygous comparison (OR = 1.21, 95%CI = 1.03–1.43, P = 0.020) and a recessive genetic model (OR = 1.21, 95%CI = 1.04–1.41, P = 0.012). In the stratification analysis by cancer type and ethnicity, similar findings were indicated for prostate cancer, breast cancer, and individuals of Asian descendant. Polyphen2 bioinformatics analysis showed that the G388R mutation is predicted to damage the protein function of FGFR4. IHS analysis indicated that FGFR4 expression is increased in advanced prostate cancer. These findings may guide personalized treatment of certain types of cancers. Up-regulation of FGFR4 may be related to a poor prognosis in prostate cancer.

Role of Fibroblast Growth Factors Receptors (FGFRs) in Brain Tumors, Focus on Astrocytoma and Glioblastoma

Despite pharmacological treatments and surgical practice options, the mortality rate of astrocytomas and glioblastomas remains high, thus representing a medical emergency for which it is necessary to find new therapeutic strategies. Fibroblast growth factors (FGFs) act through their associated receptors (FGFRs), a family of tyrosine kinase receptors consisting of four members (FGFR1-4), regulators of tissue development and repair. In particular, FGFRs play an important role in cell proliferation, survival, and migration, as well as angiogenesis, thus their gene alteration is certainly related to the development of the most common diseases, including cancer. FGFRs are subjected to multiple somatic aberrations such as chromosomal amplification of FGFR1; mutations and multiple dysregulations of FGFR2; and mutations, translocations, and significant amplifications of FGFR3 and FGFR4 that correlate to oncogenesis process. Therefore, the in-depth study of these receptor systems could help to understand the etiology of both astrocytoma and glioblastoma so as to achieve notable advances in more effective target therapies. Furthermore, the discovery of FGFR inhibitors revealed how these biological compounds improve the neoplastic condition by demonstrating efficacy and safety. On this basis, this review focuses on the role and involvement of FGFRs in brain tumors such as astrocytoma and glioblastoma.

FGFR4: A promising therapeutic target for breast cancer and other solid tumors

The fibroblast growth factor receptor (FGFR) signaling pathway has long been known to cancer researchers because of its role in cell survival, proliferation, migration, and angiogenesis. Dysregulation of FGFR signaling is frequently reported in cancer studies, but most of these studies focus on FGFR1-3. However, there is growing evidence implicating an important and unique role of FGFR4 in oncogenesis, tumor progression, and resistance to anti-tumor therapy in multiple types of cancer. Importantly, there are several novel FGFR4-specific inhibitors in clinical trials, making FGFR4 an attractive target for further research. In this review, we focus on assessing the role of FGFR4 in cancer, with an emphasis on breast cancer. First, the structure, physiological functions and downstream signaling pathways of FGFR4 are introduced. Next, different mechanisms reported to cause aberrant FGFR4 activation and their functions in cancer are discussed, including FGFR4 overexpression, FGF ligand overexpression, FGFR4 somatic hotspot mutations, and the FGFR4 G388R single nucleotide polymorphism. Finally, ongoing and recently completed clinical trials targeting FGFRs in cancer are reviewed, highlighting the therapeutic potential of FGFR4 inhibition for the treatment of breast cancer.

The FGF/FGFR system in the physiopathology of the prostate gland

Fibroblast growth factors (FGFs) are a family of proteins possessing paracrine, autocrine, or endocrine functions in a variety of biological processes, including embryonic development, angiogenesis, tissue homeostasis, wound repair, and cancer. Canonical FGFs bind and activate tyrosine kinase FGF receptors (FGFRs), triggering intracellular signaling cascades that mediate their biological activity. Experimental evidence indicates that FGFs play a complex role in the physiopathology of the prostate gland that ranges from essential functions during embryonic development to modulation of neoplastic transformation. The use of ligand- and receptor-deleted mouse models has highlighted the requirement for FGF signaling in the normal development of the prostate gland. In adult prostate, the maintenance of a functional FGF/FGFR signaling axis is critical for organ homeostasis and function, as its disruption leads to prostate hyperplasia and may contribute to cancer progression and metastatic dissemination. Dissection of the molecular landscape modulated by the FGF family will facilitate ongoing translational efforts directed toward prostate cancer therapy.

Recurrent secondary genomic alterations in desmoplastic small round cell tumors

BACKGROUND

Desmoplastic small round cell tumor (DSRCT) is a rare, highly aggressive, translocation-associated soft-tissue sarcoma that primarily affects children, adolescents, and young adults, with a striking male predominance. It is characterized by t(11;22) generating a novel EWSR1-WT1 fusion gene. Secondary genomic alterations are rarely described.

METHODS

Tumor tissue from 83 DSRCT patients was assayed by hybrid-capture based comprehensive genomic profiling, FoundationOne® Heme next generation sequencing analysis of 406 genes and RNA sequencing of 265 genes. Tumor mutation burden was calculated from a minimum of 1.4 Mb sequenced DNA. Microsatellite instability status was determined by a novel algorithm analyzing 114 specific loci.

RESULTS

Comprehensive genomic profiling identified several genomically-defined DSRCT subgroups. Recurrent genomic alterations were most frequently detected in FGFR4, ARID1A, TP53, MSH3, and MLL3 genes. With the exception of FGFR4, where the genomic alterations predicted activation, most of the alterations in the remaining genes predicted gene inactivation. No DSRCT were TMB or MSI high.

CONCLUSIONS

In summary, recurrent secondary somatic alterations in FGFR4, ARID1A, TP53, MSH3, and MLL3 were detected in 82% of DSRCT, which is significantly greater than previously reported. These alterations may have both prognostic and therapeutic implications.

Role of fibroblast growth factor 4 in the growth and metastasis of colorectal cancer

The role of fibroblast growth factor receptor 4 (FGFR4) in colorectal cancer (CRC) is poorly characterized. Therefore, the objective of the current study was to investigate the expression levels of FGFR4 in colorectal cancer and its prognostic value, and clarify the role of FGFR4 in the proliferation and metastasis of colorectal cancer cells. Immunohistochemistry was used to detect the association between FGFR4 expression and clinicopathological features in colorectal cancer tissues. The effect of FGFR4 silencing on tumor cell proliferation, cell cycle, apoptosis, migration and invasion was evaluated via lentiviral transfection of the colorectal cancer cell line SW620. Western blot analysis was used to detect the changes of epithelial‑mesenchymal transition (EMT) markers, following FGFR4 silencing. FGFR4 is upregulated in CRC tissues compared with normal tissues. Patients with high FGFR4 expression exhibited a lower 5‑year survival rate compared with patients with low FGFR4 expression (64 vs. 74%). FGFR4 silencing reduced proliferation, inhibited cell invasion, arrested cells in S phase and promoted apoptosis in colorectal cancer cells. FGFR4 silencing partially reversed EMT progression and FGFR4 this effect was enhanced in the presence of XAV939 (a β‑catenin inhibitor). The current data suggest that FGFR4 may be associated with prognosis in patients with colorectal cancer. In vitro functional tests revealed that FGFR4 may represent an effective therapeutic target for colorectal cancer. FGFR4 may also regulate EMT via the Wnt/β‑catenin pathway.

Targeting the TMPRSS2/ERG fusion mRNA using liposomal nanovectors enhances docetaxel treatment in prostate cancer

BACKGROUND

The TMPRSS2/ERG (TE) fusion gene is present in half of the prostate cancers (PCas). The TMPRSS2 and ERG junction of the fusion messenger RNA (mRNA) constitutes a cancer-specific target. Although docetaxel-based chemotherapy is the second line of therapy following development resistance to androgen ablation therapies, it is not curative. Therefore, the development of nontoxic novel monotherapies for targeting TE mRNA in PCa patients and for increasing the clinical efficacy of docetaxel treatment are needed.

METHODS

We evaluated multiple approaches to enhance the delivery of TE small interfering RNA (siRNA) containing liposomes including PEGylation, topical treatment with nitroglycerin (NG) to increase permeability and retention, and three different PEG modifications: folate, RGD cyclic peptide, and a bFGF fibroblast growth factor receptor-targeting peptide. The efficacy of the optimized TE siRNA liposome in combination with docetaxel was then evaluated in vivo with or without topical NG in vivo using a VCaP xenograft model. TE fusion protein knockdown in residual tumors was assessed using Western blotting and immunohistochemistry.

RESULTS

In vivo therapeutic targeting of TE fusion gene by systemic delivery of RGD-peptide-coated liposomal siRNA nanovectors led to sustained target silencing, suppressed tumor growth in xenograft models and enhanced the efficacy of docetaxel chemotherapy. Simultaneous application of the vasodilator NG to the skin further increased tissue the delivery of siRNA and enhanced target knockdown.

CONCLUSION

TE-targeted gene silencing therapy using liposomal nanovectors is a potential therapeutic strategy as a monotherapy and to enhance the efficacy of chemotherapy in patients with advanced PCa.

Investigation of new candidate genes in retinoblastoma using the TruSight One "clinical exome" gene panel

BACKGROUND

Retinoblastoma (Rb) is the most prevalent intraocular pediatric malignancy of the retina. Significant genetic factors are known to have a role in the development of Rb.

METHODS

Here, we report the mutation status of 4813 clinically significant genes in six patients with noncarrier of RB1 gene mutation and having normal RB1 promoter methylation from three families having higher risk for developing Rb in the study.

RESULTS

A total of 27 variants were detected in the study. Heterozygous missense variants c.1162G > A (p.Gly388Arg) in the FGFR4 gene; c.559C > T (p.Pro187Ser) in the NQO1 gene were identified. The family based evaluation of the variants showed that the variant, c.714T > G (p.Tyr238Ter), in the CLEC7A gene in first family; the variant, c.55C > T (p.Arg19Ter), in the APOC3 gene and the variant, c.1171C > T (p.Gln391Ter), in the MUTYH gene in second family; and the variant, c.211G > A (p.Gly71Arg), in the UGT1A1 gene in the third family, were found statistically significant (p < 0.05).

CONCLUSION

This study might be an important report on emphazing the mutational status of other genes in patients without RB1 gene mutations and having high risk for developing Rb. The study also indicates the interaction between the retinoic acid pathway and Rb oncogenesis for the first time.

Nonsteroidal FXR Ligands: Current Status and Clinical Applications

FXR agonists have demonstrated very promising clinical results in the treatment of liver disorders such as primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), and nonalcoholic steatohepatitis (NASH). NASH, in particular, is one of the last uncharted white territories in the pharma landscape, and there is a huge medical need and a large potential pharmaceutical market for a NASH pharmacotherapy. Clinical efficacy superior to most other treatment options was shown by FXR agonists such as obeticholic acid (OCA) as they improved various metabolic features including liver steatosis as well as liver inflammation and fibrosis. But OCA's clinical success comes with some major liabilities such as pruritus, high-density lipoprotein cholesterol (HDL_c) lowering, low-density lipoprotein cholesterol (LDL_c) increase, and a potential for drug-induced liver toxicity. Some of these effects can be attributed to on-target effects exerted by FXR, but with others it is not clear whether it is FXR- or OCA-related. Therefore a quest for novel, proprietary FXR agonists is ongoing with the aim to increase FXR potency and selectivity over other proteins and to overcome at least some of the OCA-associated clinical side effects through an improved pharmacology. In this chapter we will discuss the historical and ongoing efforts in the identification and development of nonsteroidal, which largely means non-bile acid-type, FXR agonists for clinical use.

Making way for suppressing the FGF19/FGFR4 axis in cancer

FGF19 is a noncanonical FGF ligand that can control a broad spectrum of physiological responses, which include bile acid homeostasis, liver metabolism and glucose uptake. Many of these responses are mediated by FGF19 binding to its FGFR4/β-klotho receptor complex and controlling activation of an array of intracellular signaling events. Overactivation of the FGF19/FGFR4 axis has been implicated in tumorigenic formation, progression and metastasis, and inhibitors of this axis have recently been developed for single agent use or in combination with other anticancer drugs. Considering the critical role of this receptor complex in cancer, this review focuses on recent developments and applications of FGF19/FGFR4-targeted therapeutics.

Aberrant FGFR Tyrosine Kinase Signaling Enhances the Warburg Effect by Reprogramming LDH Isoform Expression and Activity in Prostate Cancer

The acquisition of ectopic fibroblast growthfactor receptor 1 (FGFR1) expression is well documented in prostate cancer progression. How it contributes to prostate cancer progression is not fully understood, although it is known to confer a growth advantage and promote cell survival. Here, we report that FGFR1 tyrosine kinase reprograms the energy metabolism of prostate cancer cells by regulating the expression of lactate dehydrogenase (LDH) isozymes. FGFR1 increased LDHA stability through tyrosine phosphorylation and reduced LDHB expression by promoting its promoter methylation, thereby shifting cell metabolism from oxidative phosphorylation to aerobic glycolysis. LDHA depletion compromised, whereas LDHB depletion enhanced the tumorigenicity of prostate cancer cells. Furthermore, FGFR1 overexpression and aberrant LDH isozyme expression were associated with short overall survival and biochemical recurrence times in patients with prostate cancer. Our results indicate that ectopic FGFR1 expression reprograms the energy metabolism of prostate cancer cells, representing a hallmark change in prostate cancer progression.Significance: FGF signaling drives the Warburg effect through differential regulation of LDHA and LDHB, thereby promoting the progression of prostate cancer.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/16/4459/F1.large.jpg Cancer Res; 78(16); 4459-70. ©2018 AACR.

Prognostic implications of fibroblast growth factor receptor 4 polymorphisms in primary breast cancer

Fibroblast growth factor receptor 4 (FGFR4) belongs to the receptor tyrosine kinase (RTK) family, and FGFR4 polymorphisms have been implicated in both normal development and cancer, including breast cancer. In the present study, we investigated correlations between polymorphisms in FGFR4 and breast cancer prognosis. The FGFR4 SNPs rs1966265 and rs351855 were genotyped in 747 breast cancer patients using the SNaPshot method. FGFR4 protein expression was detected by immunohistochemistry in 339 samples. SNP rs351855 was correlated with FGFR4 protein expression under dominant and co-dominant models. Lymph node metastasis (LNM), ER (estrogen receptor) status, and molecular subtype were associated with high FGFR4 expression. Univariate analysis revealed rs351855 (CC/CT: P = 0.027, CC/TT: P < 0.001, CC/CT + TT: P = 0.005) to be a prognostic predictor, and multivariate analysis indicated rs351855 (CC/TT: P = 0.005) to be an independent prognostic factor. Kaplan-Meier survival analysis showed that high FGFR4 protein expression was associated with a poor prognosis. SNP rs351855 was correlated with worse outcomes, with a dose-dependent effect. The results of this study show that FGFR4 SNP rs351855 is associated with up-regulation of FGFR4 protein expression and a worse prognosis in breast cancer.

Functional FGFR4 Gly388Arg polymorphism contributes to cancer susceptibility: Evidence from meta-analysis

Fibroblast growth factor receptor 4 (FGFR4) is a member of receptor tyrosine kinase family. A functional Gly388Arg (rs351855 G>A) polymorphism in FGFR4 gene causes a glycine-to-arginine change at codon 388 within the transmembrane domain of the receptor. Although the FGFR4 rs351855 G>A polymorphism has been implicated in cancer development, its association with cancer risk remains controversial. Here, we have systematically analyzed the association between the rs351855 G>A polymorphism and cancer risk by performing a meta-analysis of 27 studies consisting of 8,682 cases and 9,731 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to measure the strength of the association. The rs351855 G>A polymorphism was associated with an increased cancer risk under the recessive model (OR=1.19, 95% CI=1.01-1.41). Stratified analysis by cancer type indicated the rs351855 G>A polymorphism was associated with an increased risk of breast and prostate cancer, but a decreased risk of lung cancer. This meta-analysis demonstrates the FGFR rs351855 G>A polymorphism is associated with increased cancer risk and suggests it could potentially serve as a chemotherapeutic target or biomarker to screen high-risk individuals.

FGFR4 polymorphic alleles modulate mitochondrial respiration: A novel target for somatostatin analog action in pituitary tumors

We reported that a single nucleotide polymorphism (SNP) at codon 388 of the fibroblast growth factor receptor 4 (FGFR4-Gly388Arg) can result in distinct proteins that alter pituitary cell growth and function. Here, we examined the differential properties of the available therapeutic somatostatin analogs, octreotide and pasireotide, in pituitary tumor cells expressing the different FGFR4 isoforms. Consistent with their enhanced growth properties, FGFR4-R388-expressing cells show higher mitochondrial STAT3 serine phosphorylation driving basal and maximal oxygen consumption rate (OCR) than pituitary cells expressing the more common FGFR4-G388 isoform. While both somatostatin analogs reduce the OCR in FGFR4-G388 cells, pasireotide was more effective in decreasing OCR in cells expressing the variant FGFR4-R388 isoform. Down-regulation of somatostatin receptor 5 (SSTR5) abrogated the effect of pasireotide, demonstrating its involvement in mediating this action. The effects on OCR were recapitulated by introducing a constitutively active serine STAT3 but not by a tyrosine-active mutant. Moreover, pharmacologic inhibition demonstrated the role for the phosphatase PP2A in mediating the dephosphorylation of STAT3-S727 by pasireotide. Our data indicate that FGFR4 polymorphic isoforms mediate signaling that yields mitochondrial therapeutic targets of relevance to the actions of different somatostatin analogs.

The ileal FGF15/19 to hepatic FGFR4 axis regulates liver regeneration after partial hepatectomy in mice

Fibroblast growth factor (FGF) has been considered to modulate liver regeneration (LR) after partial hepatectomy (PH) at the tissue level. Previous studies have demonstrated that FGF15 and FGF19 induce the activation of its receptor, FGF receptor 4 (FGFR4), which can promote hepatocellular carcinoma progression and regulate liver lipid metabolism. In this study, we aimed to explore the role of the ileal FGF15/19- hepatic FGFR4 axis in the LR after PH. Male C57BL/6 mice aged 8-12 weeks were partially hepatectomized and assessed for expression of ileal FGF15/19 to hepatic FGFR4 signaling. We used recombinant human FGF19 protein and a small interfering RNA (siRNA) of FGFR4 to regulate expression of the FGF15/19-FGFR4 axis in vitro and in vivo. The proliferation and cell cycle of hepatocytes, the expression levels of FGF15/19-FGFR4 downstream molecules, liver recovery, and lipid metabolism were assessed. We found that both ileal and serum FGF15 expression were upregulated and hepatic FGFR4 was activated after PH in mice. FGF15/19 promoted cell cycle progression, enhanced proliferation, and reduced hepatic lipid accumulation of hepatocytes both in vitro and in vivo. Furthermore, the proliferative effect and lipid regulatory properties of FGF15/19 were dependent on FGFR4 in hepatocytes. In addition, ileal FGF15/19-hepatic FGFR4 transduction during hepatocyte proliferation was regulated by extracellular regulated protein kinase (ERK) 1/2. In conclusion, the ileal FGF15/19 to hepatic FGFR4 axis is activated and promotes LR after PH in mice, supporting the potential of ileal FGF15/19 to hepatic FGFR4 axis-targeted therapy to enhance LR after PH.

Fibroblast growth factor receptor signaling plays a key role in transformation induced by the TMPRSS2/ERG fusion gene and decreased PTEN

Prostate cancer is the most common visceral malignancy and the second leading cause of cancer deaths in US men. Correlative studies in human prostate cancers reveal a frequent association of the TMPRSS2/ERG (TE) fusion gene with loss of PTEN and studies in mouse models reveal that ERG expression and PTEN loss synergistically promote prostate cancer progression. To determine the mechanism by which ERG overexpression and PTEN loss leads to transformation, we overexpressed the TE fusion gene and knocked down PTEN in an immortalized but non-transformed prostate epithelial cell line. We show that ERG overexpression in combination with PTEN loss can transform these immortalized but non-tumorigenic cells, while either alteration alone was not sufficient to fully transform these cells. Expression microarray analysis revealed extensive changes in gene expression in cells expressing the TE fusion with loss of PTEN. Among these gene expression changes was increased expression of multiple FGF ligands and receptors. We show that activation of fibroblast growth factor receptor signaling plays a key role in transformation induced by TE fusion gene expression in association with PTEN loss. In addition, in vitro and in silico analysis reveals PTEN loss is associated with widespread increases in FGF ligands and receptors in prostate cancer. Inhibitors of FGF receptor signaling are currently entering the clinic and our results suggests that FGF receptor signaling is a therapeutic target in cancers with TE fusion gene expression and PTEN loss.

A novel cell membrane affinity sample pretreatment technique for recognition and preconcentration of active components from traditional Chinese medicine

We describe a novel biomembrane affinity sample pretreatment technique to quickly screen and preconcentrate active components from traditional Chinese medicine (TCM), which adopts cell membrane coated silica particles (CMCSPs) as affinity ligands which benefit the biomembrane's ability to maximize simulation of drug-receptor interactions in vivo. In this study, the prepared CMCSPs formed by irreversible adsorption of fibroblast growth factor receptor 4 (FGFR4) cell membrane on the surface of silica were characterized using different spectroscopic and imaging instruments. Drug binding experiments showed the excellent adsorption rate and adsorption capacity of FGFR4/CMCSPs compared with non-coated silica particles. The FGFR4/CMCSPs were used as solid-phase extraction sorbents to pretreat the TCM Aconitum szechenyianum Gay. The resultant FGFR4/CMCSPs exhibited good performance. In addition, high selectivity and recognition ability of the FGFR4/CMCSPs were determined by selectivity experiments. Four alkaloid were screened and identified, one of these alkaloid, napellonine, showed favorable anti-tumor activity in preliminary pharmacological verification trials including cell proliferation and molecular docking assays. The proposed cell membrane affinity sample pretreatment method is a reliable, effective and time-saving method for fast screening and enriching active compounds and can be extended to pretreat other TCMs as leading compounds resources.

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.

Prognostic significance of fibroblast growth factor receptor 4 polymorphisms on biochemical recurrence after radical prostatectomy in a Chinese population

Fibroblast growth factor receptor 4 (FGFR4) is a transmembrane receptor with ligand-induced tyrosine kinase activity and is involved in various biological and pathological processes. Several polymorphisms of FGFR4 are associated with the incidence and mortality of numerous cancers, including prostate cancer. In this study, we investigated whether the polymorphisms of FGFR4 influence the biochemical recurrence of prostate cancer in Chinese men after radical prostatectomy. Three common polymorphisms (rs1966265, rs2011077, and rs351855) of FGFR4 were genotyped from 346 patients with prostate cancer by using the Sequenom MassARRAY system. Kaplan–Meier curves and Cox proportional hazard models were used for survival analysis. Results showed biochemical recurrence (BCR) free survival was significantly affected by the genotypes of rs351855 but not influenced by rs1966265 and rs2011077. After adjusting for other variables in multivariable analysis, patients with rs351855 AA/AG genotypes showed significantly worse BCR-free survival than those with the GG genotype (HR = 1.873; 95% CI, 1.209–2.901; P = 0.005). Hence, FGFR4 rs351855 could be a novel independent prognostic factor of BCR after radical prostatectomy in the Chinese population. This functional polymorphism may also provide a basis for surveillance programs. Additional large-scale studies must be performed to validate the significance of this polymorphism in prostate cancer.

Association of FGFR3 and FGFR4 gene polymorphisms with breast cancer in Chinese women of Heilongjiang province

BACKGROUND

The fibroblast growth factor (FGF) receptor pathway is activated in many tumors. FGFR2 has been identified as a breast cancer susceptibility gene. Common variation in other FGF receptors might also affect breast cancer risk. We carried out a case-control study to investigate associations of variants in FGFR3 and FGFR4 with breast cancer in women from Heilongjiang Province.

METHODS

SNP rs2234909 and rs3135848 in FGFR3 and rs1966265 and rs351855 in FGFR4 were successfully genotyped in 747 breast cancer patients and 716 healthy controls using the SNaPshot method. The associations between SNPs and breast cancer were examined by logistic regression. The associations between SNPs and disease characteristics were examined by chi-square tests or one-way ANOVA as needed.

RESULTS

The minor alleles of rs1966265 and rs351855 in FGFR4 were strongly associated with breast cancer in the population, with odds ratios of 1.335 (95%CI = 1.154-1.545) and 1.364 (95%CI = 1.177-1.580), respectively. However, no significant associations were detected between other SNPs and breast cancer. Analyses of the disease characteristics showed that SNP rs351855 was associated with lymph-node-positive breast cancer with a dose-dependent effect of the minor allele (P = 0.008).

CONCLUSIONS

SNPs rs1966265 and rs351855 in FGFR4 were associated with breast cancer in a northern Chinese population.

Predictive factors of response to mTOR inhibitors in neuroendocrine tumours

Medical treatment of neuroendocrine tumours (NETs) has drawn a lot of attention due to the recent demonstration of efficacy of several drugs on progression-free survival, including somatostatin analogs, small tyrosine kinase inhibitors and mTOR inhibitors (or rapalogs). The latter are approved as therapeutic agents in advanced pancreatic NETs and have been demonstrated to be effective in different types of NETs, with variable efficacy due to the development of resistance to treatment. Early detection of patients that may benefit from rapalogs treatment is of paramount importance in order to select the better treatment and avoid ineffective and expensive treatments. Predictive markers for therapeutic response are under intensive investigation, aiming at a tailored patient management and more appropriate resource utilization. This review summarizes the available data on the tissue, circulating and imaging markers that are potentially predictive of rapalog efficacy in NETs.

A Polymorphism in the FGFR4 Gene Is Associated With Risk of Neuroblastoma and Altered Receptor Degradation

BACKGROUND

Outcomes for children with high-risk neuroblastoma are poor, and improved understanding of the mechanisms underlying neuroblastoma pathogenesis, recurrence, and treatment resistance will lead to improved outcomes. Aberrant growth factor receptor expression and receptor tyrosine kinase signaling are associated with the pathogenesis of many malignancies. A germline polymorphism in the FGFR4 gene is associated with increased receptor expression and activity and with decreased survival, treatment resistance, and aggressive disease for many malignancies. We therefore investigated the role of this FGFR4 polymorphism in neuroblastoma pathogenesis.

MATERIALS AND METHODS

Germline DNA from neuroblastoma patients and matched controls was assessed for the FGFR4 Gly/Arg388 polymorphism by RT-PCR. Allele frequencies were assessed for association with neuroblastoma patient outcomes and prognostic features. Degradation rates of the FGFR4 Arg388 and Gly388 receptors and rates of receptor internalization into the late endosomal compartment were measured.

RESULTS

Frequency of the FGFR4 AA genotype and the prevalence of the A allele were significantly higher in patients with neuroblastoma than in matched controls. The Arg388 receptor demonstrated slower degradation than the Gly388 receptor in neuroblastoma cells and reduced internalization into multivesicular bodies.

CONCLUSIONS

The FGFR4 Arg388 polymorphism is associated with an increased prevalence of neuroblastoma in children, and this association may be linked to differences in FGFR4 degradation rates. Our study provides the first evidence of a role for FGFR4 in neuroblastoma, suggesting that FGFR4 genotype and the pathways regulating FGFR4 trafficking and degradation may be relevant for neuroblastoma pathogenesis.

Function of phosphorylation of NF-kB p65 ser536 in prostate cancer oncogenesis

Majority of prostate cancer (PCa) patients carry TMPRSS2/ERG (T/E) fusion genes and there has been tremendous interest in understanding how the T/E fusion may promote progression of PCa. We showed that T/E fusion can activate NF-kB pathway by increasing phosphorylation of NF-kB p65 Ser536 (p536), but the function of p536 has never been studied in PCa. We report here that active p536 can significantly increase cell motility and transform PNT1a cells (an immortalized normal cell line), suggesting p536 plays a critical role in promoting PCa tumorigenesis. We have discovered a set of p536 regulated genes, among which we validated the regulation of CCL2 by p536. Based on all evidence, we favor that T/E fusion, NF-kB p536 and CCL2 form a signaling chain. Finally, PNT1a cells (not tumorigenic) can form tumors in SCID mice when overexpressing of either wild type or active p65 in the presence of activated AKT, demonstrating synergistic activities of NF-kB and AKT signals in promoting PCa tumorigenesis. These findings indicate that combination therapies targeting T/E fusion, NF-kB, CCL2 and/or AKT pathways may have efficacy in T/E fusion gene expressing PCa. If successful, such targeted therapy will benefit more than half of PCa patients who carry T/E fusions.

Fibroblast growth factors, old kids on the new block

The fibroblast growth factors (FGFs) are a family of cell intrinsic regulatory peptides that control a broad spectrum of cellular activities. The family includes canonic FGFs that elicit their activities by activating the FGF receptor (FGFR) tyrosine kinase and non-canonic members that elicit their activities intracellularly and via FGFR-independent mechanisms. The FGF signaling axis is highly complex due to the existence of multiple isoforms of both ligands and receptors, as well as cofactors that include the chemically heterogeneous heparan sulfate (HS) cofactors, and in the case of endocrine FGFs, the Klotho coreceptors. Resident FGF signaling controls embryonic development, maintains tissue homeostasis, promotes wound healing and tissue regeneration, and regulates functions of multiple organs. However, ectopic or aberrant FGF signaling is a culprit for various diseases, including congenital birth defects, metabolic disorder, and cancer. The molecular mechanisms by which the specificity of FGF signaling is achieved remain incompletely understood. Since its application as a druggable target has been gradually recognized by pharmaceutical companies and translational researchers, understanding the determinants of FGF signaling specificity has become even more important in order to get into the position to selectively suppress a particular pathway without affecting others to minimize side effects.

The over-expression of FGFR4 could influence the features of gastric cancer cells and inhibit the efficacy of PD173074 and 5-fluorouracil towards gastric cancer

The aim was to investigate the function of fibroblast growth factor receptor 4 (FGFR4) in gastric cancer (GC) and explore the treatment value of agent targeted to FGFR4. Function assays in vitro and in vivo were performed to investigate the discrepancy of biological features among the GC cells with different expression of FGFR4. GC cells were treated with the single and combination of PD173074 (PD, an inhibitor of FGFR4) and 5-fluorouracil (5-Fu). The invasion ability were stronger, and the apoptosis rates were lower in MGC803 and BGC823 cells treated with FGFR4-LV5 (over-expression of FGFR4 protein) (P < 0.05). The proliferation ability of GC cells is reduced when treated by the single and combination of 5-Fu and PD while that of the FGFR4-LV5 group was less inhibited compared with control group (P < 0.05). The apoptosis rates are remarkably increased in GC cells treated with the single and combination of 5-Fu and PD (P < 0.05). However, the apoptosis rate obviously is reduced in GC cells treated with FGFR4-LV5 compared with control group (P < 0.05). The expression of PCNA and Bcl-XL is remarkably decreased, and the expression of Caspase-3 and cleaved Caspase-3 is obviously increased in GC cells treated with the single and combination of 5-Fu and PD. The tumor volumes of nude mice in FGFR4-LV5 group were much more increased (P < 0.05). The over-expression of FGFR4 enhanced the proliferation ability of GC in vitro and in vivo. The combination of 5-Fu and PD exerted synergetic effect in weakening the proliferation ability and promoting apoptosis in GC cells, while the over-expression of FGFR4 might inhibit the efficacy of two drugs.

Targeting FGF19/FGFR4 Pathway: A Novel Therapeutic Strategy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a lethal cancer with limited systemic therapeutic options. Liver carcinogenesis is a complex procedure and various pathways have been found to be deregulated which are potential targets for novel treatments. Aberrant signalling through FGF19 and its receptor FGFR4 seems to be the oncogenic driver for a subset of HCCs and is associated with poor prognosis. Inhibition of the pathway in preclinical models has shown antitumour activity and has triggered further evaluation of this strategy to in vivo models. This review aims to describe the role of the FGF19/FGFR4 pathway in hepatocellular carcinoma and its role as a potential predictive biomarker for novel targeted agents against FGF19/FGFR4 signalling.

Is fibroblast growth factor receptor 4 a suitable target of cancer therapy?

Fibroblast growth factors (FGF) and their tyrosine kinase receptors (FGFR) support cell proliferation, survival and migration during embryonic development, organogenesis and tissue maintenance and their deregulation is frequently observed in cancer development and progression. Consequently, increasing efforts are focusing on the development of strategies to target FGF/FGFR signaling for cancer therapy. Among the FGFRs the family member FGFR4 is least well understood and differs from FGFRs1-3 in several aspects. Importantly, FGFR4 deletion does not lead to an embryonic lethal phenotype suggesting the possibility that its inhibition in cancer therapy might not cause grave adverse effects. In addition, the FGFR4 kinase domain differs sufficiently from those of FGFRs1-3 to permit development of highly specific inhibitors. The oncogenic impact of FGFR4, however, is not undisputed, as the FGFR4-mediated hormonal effects of several FGF ligands may also constitute a tissue-protective tumor suppressor activity especially in the liver. Therefore it is the purpose of this review to summarize all relevant aspects of FGFR4 physiology and pathophysiology and discuss the options of targeting this receptor for cancer therapy.

Hyperactivated FRS2α-mediated signaling in prostate cancer cells promotes tumor angiogenesis and predicts poor clinical outcome of patients

Metastasis of tumors requires angiogenesis, which is comprised of multiple biological processes that are regulated by angiogenic factors. The fibroblast growth factor (FGF) is a potent angiogenic factor and aberrant FGF signaling is a common property of tumors. Yet, how the aberration in cancer cells contributes to angiogenesis in the tumor is not well understood. Most studies of its angiogenic signaling mechanisms have been in endothelial cells. FGF receptor substrate 2α (FRS2α) is an FGF receptor-associated protein required for activation of downstream signaling molecules that include those in the mitogen-activated protein and AKT kinase pathways. Herein, we demonstrated that overactivation and hyperactivity of FRS2α, as well as overexpression of cJUN and HIF1α, were positively correlated with vessel density and progression of human prostate cancer (PCa) toward malignancy. We also demonstrate that FGF upregulated the production of vascular endothelial growth factor A mainly by increasing expression of cJUN and HIF1α. This then promoted recruitment of endothelial cells and vessel formation for the tumor. Tumor angiogenesis in mouse PCa tissues was compromised by tissue-specific ablation of Frs2α in prostate epithelial cells. Depletion of Frs2α expression in human PCa cells and in a preclinical xenograft model, MDA PCa 118b, also significantly suppressed tumor angiogenesis accompanied with decreased tumor growth in the bone. The results underscore the angiogenic role of FRS2α-mediated signaling in tumor epithelial cells in angiogenesis. They provide a rationale for treating PCa with inhibitors of FGF signaling. They also demonstrate the potential of overexpressed FRS2α as a biomarker for PCa diagnosis, prognosis and response to therapies.

Overexpression of FGF9 in prostate epithelial cells augments reactive stroma formation and promotes prostate cancer progression

Bone metastasis is the major cause of morbidity and mortality of prostate cancer (PCa). Fibroblast growth factor 9 (FGF9) has been reported to promote PCa bone metastasis. However, the mechanism by which overexpression of FGF9 promotes PCa progression and metastasis is still unknown. Herein, we report that transgenic mice forced to express FGF9 in prostate epithelial cells (F9TG) developed high grade prostatic intraepithelial neoplasia (PIN) in an expression level- and time-dependent manner. Moreover, FGF9/TRAMP bigenic mice (F9TRAMP) grew advanced PCa earlier and had higher frequencies of metastasis than TRAMP littermates. We observed tumor microenvironmental changes including hypercellularity and hyperproliferation in the stromal compartment of F9TG and F9TRAMP mice. Expression of TGFβ1, a key signaling molecule overexpressed in reactive stroma, was increased in F9TG and F9TRAMP prostates. Both in vivo and in vitro data indicated that FGF9 promoted TGFβ1 expression via increasing cJun-mediated signaling. Moreover, in silico analyses showed that the expression level of FGF9 was positively associated with expression of TGFβ1 and its downstream signaling molecules in human prostate cancers. Collectively, our data demonstrated that overexpressing FGF9 in PCa cells augmented the formation of reactive stroma and promoted PCa initiation and progression.

FGFR as potential target in the treatment of squamous non small cell lung cancer

To date therapeutic options for squamous cell lung cancer patients remain scarce because no druggable targets have been identified so far. Aberrant signaling by FGFs (fibroblast growth factors) and FGFRs (fibroblast growth factors receptors) has been implicated in several human cancers and, particularly, in squamous non-small cell lung cancer (NSCLC). FGFR gene amplifications, somatic missense mutations, chromosomal translocations are the most frequent mechanisms able to induce aberrant activation of this pathway. Data from literature have established that the presence of an aberrant FGFR signaling has to be considered a possible negative prognostic factor but predictive of potential sensitivity to FGFR inhibitors. In the last years, clinical research efforts allowed to identify and evaluate promising FGFR inhibitors, such as monoclonal antibodies, ligand traps, non-selective or selective tyrosine kinase inhibitors. This review summarizes the current knowledge about FGFR alterations in NSCLC and the relative inhibitors in development, in particular in squamous NSCLC.

Functions of Fibroblast Growth Factor Receptors in cancer defined by novel translocations and mutations

The four receptor tyrosine kinases (RTKs) within the family of Fibroblast Growth Factor Receptors (FGFRs) are critical for normal development but also play an enormous role in oncogenesis. Mutations and/or abnormal expression often lead to constitutive dimerization and kinase activation of FGFRs, and represent the primary mechanism for aberrant signaling. Sequencing of human tumors has revealed a plethora of somatic mutations in FGFRs that are frequently identical to germline mutations in developmental syndromes, and has also identified novel FGFR fusion proteins arising from chromosomal rearrangements that contribute to malignancy. This review details approximately 200 specific point mutations in FGFRs and 40 different fusion proteins created by translocations involving FGFRs that have been identified in human cancer. This review discusses the effects of these genetic alterations on downstream signaling cascades, and the challenge of drug resistance in cancer treatment with antagonists of FGFRs.

Fibroblast growth factor receptor 4 polymorphism is associated with liver cirrhosis in hepatocarcinoma

Background

Fibroblast growth factor receptor 4 (FGFR4) polymorphisms are positively correlated with tumor progression in numerous malignant tumors. However, the association between FGFR4 genetic variants and the risk of hepatocellular carcinoma (HCC) has not yet been determined. In this study, we investigated the potential associations of FGFR4 single nucleotide polymorphisms (SNPs) with HCC susceptibility and its clinicopathological characteristics.

Methodology/Principal Findings

Four SNPs in FGFR4 (rs1966265, rs351855, rs2011077, and rs7708357) were analyzed among 884 participants, including 595 controls and 289 patients with HCC. The samples were further analyzed to clarify the associations between these gene polymorphisms and the risk of HCC, and the impact of these SNPs on the susceptibility and clinicopathological characteristics of HCC. After adjusting for other covariants, HCC patients who carrying at least one A genotype (GA and AA) at rs351855 were observed to have a higher risk of liver cirrhosis compared with those carrying the wild-type genotype (GG) (OR: 2.113, 95% CI: 1.188–3.831). Moreover, the patients with at least one A genotype were particularly showed a high level of alpha-fetoprotein (AFP).

Conclusions

Our findings suggest that genetic polymorphism in FGFR4 rs351855 may be associated with the risk of HCC coupled with liver cirrhosis and may markedly increase the AFP level in Taiwanese patients with HCC. In addition, this is the first study that evaluated the risk factors associated with FGFR4 polymorphism variants in Taiwanese patients with HCC.

FGFR4 polymorphic variants modulate phenotypic features of Cushing disease

Cushing disease is a potentially lethal condition resulting from hormone excess, usually due to a small pituitary tumor that fails to respond to negative feedback inhibition. A minority of patients develop larger, more aggressive tumors of the same lineage but with modest hormone excess. Here we show that a common polymorphism in the fibroblast growth factor receptor 4 (FGFR4) transmembrane domain yields receptor isoforms with distinct properties that mediate these biological differences. Forced expression of the major FGFR4-G388 variant allele supports pY-signal transducer and activator of transcription (STAT3) responses. In contrast, expression of the minor FGFR4-R388 allele enhances STAT3 serine phosphorylation, driving cellular growth. In addition, FGFR4-R388 enhances glucocorticoid receptor phosphorylation and nuclear translocation. Consistent with these findings, glucocorticoid administration resulted in enhanced hormone negative feedback in mice with knock-in of the FGFR4 variant allele. Moreover, clinical data from patients with pituitary tumors revealed that those homozygous for the R388 allele have a higher frequency of silent corticotroph macroadenomas than FGFR4-G388 carriers, who were more likely to have small but hormonally active microadenomas. These findings demonstrate that the FGFR4 transmembrane polymorphic variants can modulate cellular growth and sensitivity to glucocorticoid hormone negative feedback through distinct STAT3 modifications of relevance to the human forms of Cushing disease.

Hypoxia-inducible factor-1α C1772T polymorphism and cancer risk: a meta-analysis including 18,334 subjects

Studies on HIF 1α C1772T (P582S) polymorphism revealed a genetic susceptibility to malignant tumors, however, the results were conflicting. We conducted a meta-analysis utilizing 29 eligible case-control studies to analyze the data concerning the association between the HIF-1α C1772T polymorphism and cancer risks. There was statistical association between the HIF-1α CT/TT genotype and cancer risk (OR = 1.28, 95% CI = 1.06-1.54, P(heterogeneity) < .00001). The stability of these observations was confirmed by a one-way sensitivity analysis. Our findings suggested that CT/TT genotype was associated with increased risks of prostate cancer. Besides, the HIF-1α C1772T polymorphism most likely contributes to susceptibility to malignant tumors, especially in American population.

Fibroblast growth factor receptor 4 (FGFR4): a targetable regulator of drug resistance in colorectal cancer

The discovery of underlying mechanisms of drug resistance, and the development of novel agents to target these pathways, is a priority for patients with advanced colorectal cancer (CRC). We previously undertook a systems biology approach to design a functional genomic screen and identified fibroblast growth factor receptor 4 (FGFR4) as a potential mediator of drug resistance. The aim of this study was to examine the role of FGFR4 in drug resistance using RNAi and the small-molecule inhibitor BGJ398 (Novartis). We found that FGFR4 is highly expressed at the RNA and protein levels in colon cancer tumour tissue compared with normal colonic mucosa and other tumours. Silencing of FGFR4 reduced cell viability in a panel of colon cancer cell lines and increased caspase-dependent apoptosis. A synergistic interaction was also observed between FGFR4 silencing and 5-fluorouracil (5-FU) and oxaliplatin chemotherapy in colon cancer cell lines. Mechanistically, FGFR4 silencing decreased activity of the pro-survival STAT3 transcription factor and expression of the anti-apoptotic protein c-FLIP. Furthermore, silencing of STAT3 resulted in downregulation of c-FLIP protein expression, suggesting that FGFR4 may regulate c-FLIP expression via STAT3. A similar phenotype and downstream pathway changes were observed following FGFR4 silencing in cell lines resistant to 5-FU, oxaliplatin and SN38 and upon exposure of parental cells to the FGFR small-molecule inhibitor BGJ398. Our results indicate that FGFR4 is a targetable regulator of chemo-resistance in CRC, and hence inhibiting FGFR4 in combination with 5-FU and oxaliplatin is a potential therapeutic strategy for this disease.

Functional roles of fibroblast growth factor receptors (FGFRs) signaling in human cancers

The fibroblast growth factor receptors (FGFRs) regulate important biological processes including cell proliferation and differentiation during development and tissue repair. Over the past decades, numerous pathological conditions and developmental syndromes have emerged as a consequence of deregulation in the FGFRs signaling network. This review aims to provide an overview of FGFR family, their complex signaling pathways in tumorigenesis, and the current development and application of therapeutics targeting the FGFRs signaling for treatment of refractory human cancers.

Combination of the FGFR4 inhibitor PD173074 and 5-fluorouracil reduces proliferation and promotes apoptosis in gastric cancer

Our previous findings revealed that FGFR4 may be a novel therapeutic target for gastric cancer. The aim of the present study was to explore the effects of a combination of PD173074 (PD) and 5-fluorouracil (5-Fu) on the biological behavior of gastric cancer cell lines and the relevant mechanisms involved. MKN45, a gastric cancer cell line, was treated with each single agent alone or a combination of FGF19, PD and 5-Fu. Then, a series of functional assays were performed using CCK-8 assay and flow cytometry. Western blot analysis was used to determine the expression of signaling pathway and downstream-related molecules in the MKN45 cells following the different treatments. As the concentration of PD and 5-Fu increased, the cell viability gradually decreased; the viability of the combination group was less than the viability following single administration. Western blot analysis showed that FGFR4 expression was weak in the 5-Fu-treated groups when compared with the control. PD markedly increased the apoptosis rate of MKN45 cells when compared to the control; the apoptosis rate in the cells treated with the combination of PD and 5-Fu was higher than that in the cells following single treatment. Furthermore, PD reduced the expression of p-ERK and Bcl-xl and increased caspase-3 expression. Inhibition of the activity of FGFR4 may be the main mechanisms of PD effect while 5-Fu reduced FGFR4 expression. Furthermore, the effects of the combination of 5-Fu and PD in inhibiting proliferation, increasing apoptosis and arresting cell cycle were superior to these effects following the single agent treatments, suggesting that the two drugs applied in combination may contribute to the effective treatment of gastric cancer.