The fibroblast growth factor receptor-4 Arg388 allele is associated with gastric cancer progression

Targeting FGFR Pathways in Gastrointestinal Cancers: New Frontiers of Treatment

In carcinogenesis of the gastrointestinal (GI) tract, the deregulation of fibroblast growth factor receptor (FGFR) signaling plays a critical role. The aberrant activity of this pathway is described in approximately 10% of gastric cancers and its frequency increases in intrahepatic cholangiocarcinomas (iCCAs), with an estimated frequency of 10-16%. Several selective FGFR inhibitors have been developed in the last few years with promising results. For example, targeting the FGFR pathway is now a fundamental part of clinical practice when treating iCCA and many clinical trials are ongoing to test the safety and efficacy of anti-FGFR agents in gastric, colon and pancreatic cancer, with variable results. However, the response rates of anti-FGFR drugs are modest and resistances emerge rapidly, limiting their efficacy and causing disease progression. In this review, we aim to explore the landscape of anti-FGFR inhibitors in relation to GI cancer, with particular focus on selective FGFR inhibitors and drug combinations that may lead to overcoming resistance mechanisms and drug-induced toxicities.

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.

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 Gly388Arg Polymorphism Affects the Progression of Gastric Cancer by Activating STAT3 Pathway to Induce Epithelial to Mesenchymal Transition

Purpose

Fibroblast growth factor receptor 4 (FGFR4) plays a critical role in cancer progression involving in tumor proliferation, invasion, and metastasis. This study clarified the role of FGFR4-Arg388 variant in gastric cancer (GC), and more importantly highlighted the possibility of this single nucleotide polymorphism (SNP) as potential therapeutic targets.

Materials and Methods

FGFR4 polymorphism was characterized in advanced GC patients to perform statistical analysis. FGFR4-dependent signal pathways involving cell proliferation, invasion, migration, and resistance to oxaliplatin (OXA) in accordance with the SNP were also assessed in transfected GC cell lines.

Results

Among 102 GC patients, the FGFR4-Arg388 patients showed significantly higher tumor stage (p=0.047) and worse overall survival (p=0.033) than the Gly388 patients. Immunohistochemical results showed that FGFR4-Arg388 patients were more likely to have higher vimentin (p=0.025) and p-STAT3 (p=0.009) expression compared with FGFR4-Gly388 patients. In transfected GC cells, the overexpression of FGFR4-Arg388 variant increased proliferation and invasion of GC cells, increasing resistance of GC cells to OXA compared with cells overexpressing the Gly388 allele.

Conclusion

The exploration mechanism may be through FGFR4-Arg388/STAT3/epithelial to mesenchymal transition axis regulating pivotal oncogenic properties of GC cells. The FGFR4-Arg388 variant may be a biomarker and a candidate target for adjuvant treatment of GC.

Identification of a novel oncogenic mutation of FGFR4 in gastric cancer

Gastric cancer remains one of the leading causes of cancer death worldwide. Despite intensive investigations of treatments over the past three decades, the poor prognosis of patients with unresectable advanced or recurrent gastric cancer has not significantly changed, and improved therapies are required. Here, we report the identification of an oncogenic mutation in FGFR4 in a human gastric tumour that leads to constitutive activation of its product, FGFR4. The G636C-FGFR4 tyrosine kinase domain mutation was found in 1 of 83 primary human gastric tumours. The G636C mutation increased FGFR4 autophosphorylation, and activated FGFR4 downstream signalling molecules and enhanced anchorage-independent cell growth when expressed in NIH/3T3 cells. 3D-structural analysis and modelling of FGFR4 suggest that G636C destabilizes an auto-inhibitory conformation and stabilizes an active conformation, leading to increased kinase activation. Ba/F3 cell lines expressing the G636C-FGFR4 mutant were significantly more sensitive to ASP5878, a selective FGFR inhibitor, than the control. Oral administration of ASP5878 significantly inhibited the growth of tumours in mice engrafted with G636C-FGFR4/3T3 cells. Together, our results demonstrate that mutationally activated FGFR4 acts as an oncoprotein. These findings support the therapeutic targeting of FGFR4 in gastric cancer.

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.

Different clinical significance of FGFR1-4 expression between diffuse-type and intestinal-type gastric cancer

Background

Receptor tyrosine kinases promote tumor progression in many cancers, although oncologic activation differs between diffuse-type gastric cancer (DGC) and intestinal-type gastric cancer (IGC). Fibroblast growth factor receptor (FGFR) is one RTK, and we previously reported the clinical significance of FGFR1, 2, 3, and 4 in gastric cancer. The aim of the present study was to reevaluate the clinical significance of FGFR1–4 expression separately in DGC and IGC.

Methods

Tumor samples, including 109 DGCs and 100 IGCs, were obtained from patients who underwent gastrectomy between 2003 and 2007 in our institution. The expression levels of FGFR1, 2, 3, and 4 were measured in the tumors by immunohistochemical analysis.

Results

In DGC, high expression of FGFR1, FGFR2, or FGFR4 was significantly associated with the depth of invasion, lymph-node metastasis, pathological stage, and distant metastasis or recurrent disease. Patients with high expression of FGFR1, FGFR2, or FGFR4 had significantly poorer disease-specific survival (DSS) (p = 0.009, p = 0.001, and p = 0.023, respectively). In IGC, only FGFR4 expression was significantly associated with factors relative to tumor progression and with shorter DSS (p = 0.012).

Conclusion

In conclusion, high FGFR4 expression correlated with tumor progression and survival in both DGC and IGC, whereas high expression of FGFR1 and 2 correlated with tumor progression and survival in only DGC.

FGFR4 Arg388 Is Correlated with Poor Survival in Resected Colon Cancer Promoting Epithelial to Mesenchymal Transition

PURPOSE

Fibroblast growth factor receptor 4 (FGFR4) plays an important role in cancer progression during tumor proliferation, invasion, and metastasis. This study evaluated the prognostic role of FGFR4 polymorphism in patients with resected colon cancer, including the underlying mechanism.

MATERIALS AND METHODS

FGFR4 polymorphism was characterized in patientswho received curative resection for stage III colon cancer. FGFR4-dependent signal pathways involving cell proliferation, invasion, and migration according to genotypes were also evaluated in transfected colon cancer cell lines.

RESULTS

Among a total of 273 patients, the GG of FGFR4 showed significantly better overall survival than the AG or AA, regardless of adjuvant treatment. In the group of AG or AA, combination of folinic acid, fluorouracil, and oxaliplatin (FOLFOX) resulted in better survival than fluorouracil/leucovorin or no adjuvant chemotherapy. However, in GG, there was no difference among treatment regimens. Using multivariate analyses, the Arg388 carriers, together with age, N stage, poor differentiation, absence of a lymphocyte response, and no adjuvant chemotherapy, had a significantly worse OS than patients with the Gly388 allele. In transfected colon cancer cells, overexpression of Arg388 significantly increased cell proliferation and changes in epithelial to mesenchymal transition markers compared with cells overexpressing the Gly388 allele.

CONCLUSION

The Arg388 allele of FGFR4 may be a biomarker and a candidate target for adjuvant treatment of patients with resected colon cancer.

Gly388Arg FGFR4 Polymorphism Is Not Predictive of Everolimus Efficacy in Well-Differentiated Digestive Neuroendocrine Tumors

INTRODUCTION

Preclinical data suggest that the single nucleotide polymorphism substituting a glycine for an arginine in codon 388 of the FGFR4 transmembrane domain may increase the proliferation of xenografted neuroendocrine cell lines and decrease their sensitivity to everolimus by modulating STAT3 signaling and the mTOR pathway.

AIM

To evaluate the prognostic and predictive values of this polymorphism on everolimus efficacy in patients treated for digestive neuroendocrine tumor (NET).

PATIENTS AND METHODS

This monocentric retrospective cohort included patients with small bowel NET (SBNET) and pancreatic NET (PNET) treated with everolimus (2006-2013). The patients were genotyped by classical sequencing, and mTOR pathway activity was assessed by immunochemistry on formalin-fixed paraffin-embedded samples (PTEN/pPTEN/pAKT/pmTOR/pS6/p4EBP1).

RESULTS

Forty-one patients (21 males, median age 57 years) with PNET (n = 28), SBNET (n = 12) or NET of unknown origin (n = 1), grade 1 (n = 8), 2 (n = 27), 3 (n = 3) or unknown grade (n = 3), were studied. At least one 388Arg allele was found in 14/23 PNET and 10/11 SBNET. Progression-free survival in the whole population and the PNET subgroup was not influenced by the presence of one or two 388Arg alleles [HR = 1.31 (0.58-2.99), p = 0.52 and HR = 1.11 (0.45-2.73), p = 0.82, respectively]. Similarly, overall survival was not influenced. Finally, mTOR pathway molecule expression was not modified by the presence of at least one 388Arg allele.

CONCLUSION

The Gly388Arg FGFR4 polymorphism does not seem to have a prognostic value in digestive NET. In addition, it neither predicts the response to everolimus nor modifies the activation of the mTOR pathway.

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.

Second-line treatment of metastatic gastric cancer: Current options and future directions

Gastric cancer remains one among the leading causes of cancer-related deaths, regardless of its decreasing incidence and newly available treatment options. Most patients present at an advanced stage and are treated with upfront systemic chemotherapy. Those patients receiving first-line therapy may initially respond to treatment, but many of them relapse over time. In such condition, second-line treatment for disease progression remains the only available option. Although there exists no standard approach in the second-line setting, several phase III trials have shown modest survival benefit in patients receiving irinotecan, taxane and ramucirumab over the best supportive care or active agents. This review analyzes the currently available treatment regimens and future directions of research in the second-line setting for metastatic gastric cancer with the best available evidence. Additionally, the prognostic factors that influence patient survival in those receiving second-line therapy are discussed.

Silencing of FGFR4 could influence the biological features of gastric cancer cells and its therapeutic value in gastric cancer

To clarify the role of fibroblast growth factor receptor 4 (FGFR4) in gastric cancer (GC) and explore the therapeutic value of BGJ398 targeted to FGFR4. We constructed lentivirus vectors to stably knockdown FGFR4 expression in GC cells. Function assays in vitro and in vivo, treated with 5-fluorouracil (5-Fu) and BGJ398, were performed to study the change of biological behaviors of GC cells and related mechanism. The proliferation and invasive ability of HGC27 and MKN45 significantly decreased while the apoptosis rate of GC cells obviously increased in shRNA group (P < 0.05). The expressions of Bcl-xl, FLIP, PCNA, vimentin, p-erk, and p-STAT3 significantly reduced while the expressions of caspase-3 and E-cadherin markly enhanced in shRNA group. The proliferation abilities of GC cells were more significantly inhibited by the combination of BGJ398 and 5-Fu in shRNA group (P < 0.05). Compared to negative control (NC), the single and combination of 5-Fu and BGJ398 all significantly increased the apoptosis rate of GC cells, especially in the combination group (P < 0.01). The single and combination of 5-Fu and BGJ398 decreased the expressions of PCNA, Bcl-xl, and FLIP while increased the expression of caspase-3 in GC cells, especially in shRNA groups. Furthermore, knockdown of FGFR4 expression might prevent the growth of GC in vivo. Silencing of FGFR4 expression could weaken the invasive ability, increase the apoptosis rate, and decrease the proliferation ability of GC cells in vitro and in vivo. Furthermore, the combination of 5-Fu and BGJ398 had synergy in inhibiting the proliferation ability and increasing apoptosis rate of GC cells, directing a new target drug in GC.

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.

The Prognostic Significance of FGFR4 Gly388 Polymorphism in Esophageal Squamous Cell Carcinoma after Concurrent Chemoradiotherapy

Purpose

The purpose of this study is to investigate the role of fibroblast growth factor receptor 4 (FGFR4) polymorphism in esophageal cancer after chemoradiotherapy (CRT).

Materials and Methods

Peripheral blood samples from 244 patients treated with CRT for esophageal squamous cell carcinoma were assessed for the role of FGFR4 genotype on treatment response and survival.

Results

A total of 94 patients were homozygous for the Gly388 allele, and 110 were heterozygous and 40 homozygous for the Arg388 allele. No significant association was found between the FGFR4 genotype and clinicopathological parameters. However, patients carrying the Gly388 allele showed a better overall response rate than Arg388 carriers (p=0.038). In addition, Gly388 allele patients at an earlier stage showed better overall survival (OS) and progression-free survival than Arg388 carriers. Among these, the Gly388 allele showed significantly improved OS compared to Arg388 carriers in the lymph node (LN) metastasis group (p=0.042) compared to the no LN metastasis group (p=0.125). However, similar survival outcomes were observed for advanced-stage disease regardless of genotype.

Conclusion

This result suggests that the role of FGFR4 Gly388 in treatment outcomes differs according to esophageal cancer stage. It showed a predictive role in the response of esophageal cancer patients to CRT with a better trend for OS in Gly388 than Arg388 carriers in the early stages. In particular, LN-positive early-stage patients carrying the Gly388 allele showed improved OS compared to those carrying Arg388.

The Fibroblast Growth Factor signaling pathway

The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs). Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins. Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways. Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels. Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning. FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactivating developmental signaling pathways. Consistent with the presence of FGFs in almost all tissues and organs, aberrant activity of the pathway is associated with developmental defects that disrupt organogenesis, impair the response to injury, and result in metabolic disorders, and cancer. For further resources related to this article, please visit the WIREs website.

Therapeutic targeting of fibroblast growth factor receptors in gastric cancer

Chemotherapy has become the global standard treatment for patients with metastatic or unresectable gastric cancer (GC), although outcomes remain unfavorable. Many molecular-targeted therapies inhibiting signaling pathways of various tyrosine kinase receptors have been developed, and monoclonal antibodies targeting human epidermal growth factor receptor 2 (HER2) have become standard therapy for HER2-positive GC. An inhibitor of vascular endothelial growth factor receptor 2 or MET has also produced promising results in patients with GC. Fibroblast growth factor receptors (FGFR) play key roles in tumor growth via activated signaling pathways in GC. Genomic amplification of FGFR2 leads to the aberrant activation found in GC tumors and is related to survival in patients with GC. This review discusses the clinical relevance of FGFR in GC and examines FGFR as a potential therapeutic target in patients with GC. Preclinical studies in animal models suggest that multitargeted tyrosine kinase inhibitors (TKIs), including FGFR inhibitor, suppress tumor cell proliferation and delay tumor progression. Several TKIs are now being evaluated in clinical trials as treatment for metastatic or unresectable GC harboring FGFR2 amplification.

Prognostic significance of the co-overexpression of fibroblast growth factor receptors 1, 2 and 4 in gastric cancer

The overexpression of fibroblast growth factor receptor (FGFR) 2 is an established prognostic factor and treatment target in gastric cancer. However, the roles of other FGFRs have not been fully elucidated. In this study, we investigated the correlations of the expression of FGFR1-4 with clinicopathological characteristics and outcomes in gastric cancer. Tumor samples were obtained from 222 patients with gastric adenocarcinoma who underwent gastrectomy between 2003 and 2007. The expression of each FGFR was measured in the tumors by immunohistochemical analysis. The overexpression of FGFR1, FGFR2 or FGFR4 was found to be significantly associated with tumor progression, including depth of invasion, lymph node metastasis, pathological stage and distant metastasis or recurrent disease. Patients exhibiting overexpression of FGFR1, FGFR2 or FGFR4 had a significantly poorer disease-specific survival (DSS; P<0.001, P=0.008 and P<0.001, respectively). Moreover, the co-overexpression of all three FGFRs was significantly associated with a poorer DSS compared to the expression of none or only one of the FGFRs (P<0.001 and P=0.001, respectively) and it was found to be an independent prognostic factor (HR=1.71, 95% CI: 1.02-2.85, P=0.041). In conclusion, high expression of FGFR1, FGFR2 or FGFR4 was associated with tumor progression and poor survival in patients with gastric cancer. Similar to FGFR2, FGFR1 and FGFR4 may be considered as prognostic factors and treatment targets in gastric cancer.

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.

Fibroblast growth factor receptor 4 Gly388Arg polymorphism in Chinese gastric cancer patients

AIM: To investigate the contribution of the fibroblast growth factor receptor 4 (FGFR4) Gly388Arg polymorphism as a genetic risk factor for gastric cancer (GC) and to investigate any associations between this polymorphism and clinicopathological parameters and survival.

METHODS: Tumors and matched adjacent non-cancer tissues were collected from 304 GC patients, and 5 mL of venous blood was collected from 62 GC patients and 392 age- and sex-matched healthy controls without cancer history from the same ethnic population. DNA was extracted, and direct sequencing analyses were performed to genotype the FGFR4 Gly388Arg polymorphism in all the samples. Differences in the genotype frequencies of the FGFR4 Gly388Arg polymorphism between GC patients and healthy controls were estimated using the χ² test. Binary logistic regression was used for all analysis variables to estimate risk as the ORs with 95%CIs. The relationships between the FGFR4 genotype and clinicopathological parameters were tested with the χ² test. The Kaplan-Meier product-limit method, the log-rank test, and the Cox regression model were applied to evaluate the effect of the FGFR4 genotype on the overall survival of patients with GC.

RESULTS: In the present GC cohort, 118 patients (38.8%) were homozygous for the Gly388 allele, 124 patients (40.8%) were heterozygous, and 62 patients (20.4%) were homozygous for the Arg388 allele. The frequencies of the Gly/Gly, Gly/Arg, and Arg/Arg genotypes in the healthy controls were 33.6%, 48.0%, and 18.4%, respectively. The distributions of genotypes (χ² = 3.589, P = 0.166) and alleles (χ² = 0.342, P = 0.559) of the FGFR4 Gly388Arg polymorphism were not different between the GC patients and the healthy controls. Although we observed no correlation between the FGFR4 Gly388Arg polymorphism and clinicopathological parameters or survival in the total cohort of GC patients, the presence of the Arg388 allele was associated with shorter survival time in patients with GC if the tumor was small (log rank χ² = 5.449, P = 0.020), well differentiated (log rank χ² = 12.798, P = 0.000), T1 or T2 stage (log rank χ² = 4.745, P = 0.029), without lymph node involvement (log rank χ² = 6.647, P= 0.010), and at an early clinical stage (log rank χ² = 4.615, P = 0.032).

CONCLUSION: Our results suggest that the FGFR4 Gly388Arg polymorphism is not a risk factor for GC cancer initiation but that it is a useful prognostic marker for GC patients when the tumor is relatively small, well differentiated, or at an early clinical stage.

The correlations between the expression of FGFR4 protein and clinicopathological parameters as well as prognosis of gastric cancer patients

BACKGROUND

Fibroblast growth factor receptor 4 (FGFR4) was seldom investigated in gastric cancer (GC). The purpose of the study was to elucidate the expression of FGFR4 protein in GC and related clinical significance.

METHODS

Ninety-four paraffin-embedded tumor specimens were obtained from Cancer Hospital, Fudan University. The expression of FGFR4 as well as p53, p21, EGFR, neu, c-myc, and PCNA were detected by immunohistochemical method. Then, correlation analysis and survival analysis were performed.

RESULTS

The expression rate of FGFR4 protein in GC tissues and normal stomach tissues was 93.6% and 30.8%, respectively (P = 0.000). The expression of FGFR4 was positively correlated with the expression of p21, neu and PCNA (P-value was 0.009, 0.012, and 0.018, respectively). Subgroup analysis showed that compared to low expression group, the prognosis of patients with III/IV stage and negative expression of p21 in high expression group of FGFR4 were worse (P = 0.048, 0.041, respectively). Multivariate analysis showed that TNM stage was the independent prognostic factor in high expression group (HR, 11.593; 95% CI, 3.532-18.058; P = 0.000).

CONCLUSIONS

High expression of FGFR4 protein, accelerating the progression of advanced GC, might be associated with a poor prognosis in patients with advanced FC.

Fibroblast growth factor receptor 4 Gly388Arg polymorphism associated with severity of gallstone disease in a Chinese population

The etiology of gallstone disease is multifactorial; supersaturation of bile with cholesterol is a primary cause for gallstone formation. In previous studies, we found that fibroblast growth factor receptor 4 (FGFR4) plays an important role in maintaining bile acid homeostasis by regulating the expression of cholesterol 7α-hydroxylase (CYP7A1), a rate-limiting enzyme for bile acid biosynthesis. The Gly388Arg (G-388R) polymorphism of FGFR4 affects stabilization and activation of FGFR4. Consequently, we studied the FGFR4 gene as a candidate gene for genetic susceptibility to gallstone disease. We found that overexpression of FGFR4, especially the G-388R mutant of FGFR4, inhibits luciferase activity of CYP7A1 reporter in HepG2 cells, indicating that the G-388R mutant of FGFR4 may have greater inhibitory activity against bile acid biosynthesis. To investigate the association of FGFR4 polymorphism with gallstone disease, 117 patients with gallstone disease and 457 controls were genotyped for FGFR4 polymorphism G-388R by PCR-RFLP. Although the incidence of gallstone disease was not greater in patients with the FGFR4 RR genotype, the ratio of gallstone patients with acute cholecystitis in the FGFR4 RR genotype (42%) was significantly higher than that in other genotypes of FGFR4 (P = 0.019). In conclusion, the FGFR4 polymorphism is a genetic risk factor contributing to aggravation of gallstone disease.

Fibroblast growth factor receptor 4 regulates proliferation and antiapoptosis during gastric cancer progression

BACKGROUND

Fibroblast growth factor receptor 4 (FGFR4) belongs to the tyrosine kinase receptor family. Little is known about the effect of FGFR4 on gastric cancer (GC). Therefore, the objective of the current study was to elucidate the role of FGFR4 in the tumorigenesis and progression of GC.

METHODS

FGFR4 and some common prognosis markers, including p53, neu, and proliferating cell nuclear antigen (PCNA), were detected in 71 tissue samples from patients with GC using immunohistochemical analysis. In addition, a series of functional assays were carried out using small interfering RNA (siRNA) and included proliferation assays, clone assays, and apoptosis detection.

RESULTS

Cytoplasmic FGFR4 expression in GC tissues was negative (7% of samples), low (14.1% of samples), intermediate (40.8%), and high (38% of samples). FGFR4 expression was associated with lymph node status and with PCNA and neu expression (P < .05). The 5-year relative survival rate was 61.5% in patients who had GC with low FGFR4 expression but was only 42% in patients who had high FGFR4 expression (P = .058). A subgroup analysis of the patients who had high FGFR4 expression revealed that those with stage III and IV disease had a worse prognosis (P = .044). Moreover, knockdown of FGFR4 expression led to decreased proliferation and an increased rate of apoptosis in the MKN45 and SGC7901 GC cell lines (P < .05). Western blot analysis demonstrated that the expression of caspase 3 increased, whereas the expression of extra-large B-cell lymphoma (Bcl-xL) decreased in MKN45 and SGC7901 cells after FGFR4-siRNA transfection.

CONCLUSIONS

FGFR4 expression in GC tissue was extremely high. The current results indicated that FGFR4 may contribute to the progression of GC by regulating proliferation and antiapoptosis, indicating that FGFR4 may be a potential, novel drug target against GC.