Fibroblast growth factor receptor 4 (FGFR4) and fibroblast growth factor 19 (FGF19) autocrine enhance breast cancer cells survival

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.

Gamma-Klotho exhibits multiple roles in tumor growth of human bladder cancer

Alpha-Klotho (KLα) and beta-Klotho (KLβ) have recently been reported to correlate with cancer prognosis in some malignancies and we previously reported the association between KLα, KLβ, and urothelial carcinoma of the bladder (UCB), indicating that KLβ acts as a tumor promoter. However, the association between gamma-Klotho (KLγ) and cancer prognosis remains unclear. In the present study, we evaluated the association between KLγ and UCB. To evaluate the effect of KLγ on human bladder cancer cell lines in vitro assays were performed. Exogenous KLγ increased the ability of human bladder cancer cells to proliferate, migrate, invade, form colonies, and provide anchorage-independent growth potential. In in vivo assays, eighteen mice bearing xenografts inoculated using UM-UC-3, were randomly divided into three groups and treated with a small interfering RNA (siRNA) by intratumoral administration once a week for four weeks. Knockdown of KLγ with siRNA led to a dramatic change in tumor growth and suggested that KLγ had effects on tumor growth, including promotion of cell proliferation, inhibition of apoptosis, and enhancement of the epithelial-mesenchymal transition. To confirm the study, human tissue samples were used and patients were divided into two groups according to KLγ expression level. High expression of KLγ was significantly associated with higher stage and grade cancer and the presence of lymphovascular invasion compared to patients with lower expression of KLγ. Our results suggest that KLγ plays an important role in tumor invasion and progression and these results may lead to the development of new therapies and diagnostic methods for UCB.

Theoretical studies on FGFR isoform selectivity of FGFR1/FGFR4 inhibitors by molecular dynamics simulations and free energy calculations

The activation and overexpression of fibroblast growth factor receptors (FGFRs) are highly correlated with a variety of cancers. Most small molecule inhibitors of FGFRs selectively target FGFR1-3, but not FGFR4. Hence, designing highly selective inhibitors towards FGFR4 remains a great challenge because FGFR4 and FGFR1 have a high sequence identity. Recently, two small molecule inhibitors of FGFRs, ponatinib and AZD4547, have attracted huge attention. Ponatinib, a type II inhibitor, has high affinity towards FGFR1/4 isoforms, but AZD4547, a type I inhibitor of FGFR1, displays much reduced inhibition toward FGFR4. In this study, conventional molecular dynamics (MD) simulations, molecular mechanics/generalized Born surface area (MM/GBSA) free energy calculations and umbrella sampling (US) simulations were carried out to reveal the principle of the binding preference of ponatinib and AZD4547 towards FGFR4/FGFR1. The results provided by MM/GBSA illustrate that ponatinib has similar binding affinities to FGFR4 and FGFR1, while AZD4547 has much stronger binding affinity to FGFR1 than to FGFR4. A comparison of the individual energy terms suggests that the selectivity of AZD4547 towards FGFR1 versus FGFR4 is primarily controlled by the variation of the van der Waals interactions. The US simulations reveal that the PMF profile of FGFR1/AZD4547 has more peaks and valleys compared with that of FGFR4/AZD4547, suggesting that the dissociation process of AZD4547 from FGFR1 are easily trapped into local minima. Moreover, it is observed that FGFR1/AZD4547 has much higher PMF depth than FGFR4/AZD4547, implying that it is more difficult for AZD4547 to escape from FGFR1 than from FGFR4. The physical principles provided by this study extend our understanding of the binding mechanisms and provide valuable guidance for the rational design of FGFR isoform selective inhibitors.

Equal Pro-inflammatory Profiles of CCLs, CXCLs, and Matrix Metalloproteinases in the Extracellular Microenvironment In Vivo in Human Dense Breast Tissue and Breast Cancer

The inflammatory microenvironment affects breast cancer progression. Proteins that govern the inflammatory response are secreted into the extracellular space, but this compartment still needs to be characterized in human breast tissues in vivo. Dense breast tissue is a major risk factor for breast cancer by yet unknown mechanisms and no non-toxic prevention for these patients exists. Here, we used the minimal invasive technique of microdialysis for sampling of extracellular proteins in live tissues in situ in breast cancers of women before surgery and in healthy women having dense or non-dense breast tissue on mammography. Proteins were profiled using a proximity extension assay. Out of the 32 proteins assessed, 26 exhibited similar profiles in breast cancers and dense breast tissues; CCL-4, -7, -8, -11, -15, -16, -22, -23, and -25, CXCL-5, -8, -9, -16 as well as sIL-6R, IL-18, vascular endothelial growth factor, TGF-α, fibroblast growth factor 19, matrix metalloproteinase (MMP)-1, -2, -3, and urokinase-type plasminogen activator were all increased, whereas CCL-3, CX3CL1, hepatocyte growth factor, and MMP-9 were unaltered in the two tissues. CCL-19 and -24, CXCL-1 and -10, and IL-6 were increased in dense breast tissue only, whereas IL-18BP was increased in breast cancer only. Our results provide novel insights in the inflammatory microenvironment in human breast cancer in situ and define potential novel therapeutic targets. Additionally, we show previously unrecognized similarities of the pro-inflammatory microenvironment in dense breast tissue and breast cancer in vivo suggesting that anti-inflammatory breast cancer prevention trials for women with dense breast tissue may be feasible.

FGF19 genetic amplification as a potential therapeutic target in lung squamous cell carcinomas

Background

Although FGF19 gene aberrations are associated with carcinogenesis and progression in human cancers, the roles of FGF19 genetic amplification and expression in Chinese patients with lung squamous cell carcinoma (LSCC) and FGF19 amplification as a potential therapeutic target for LSCC are not well understood.

Methods

Fluorescence in situ hybridization analysis and quantitative real‐time‐PCR was used to detect FGF19 genetic amplification and FGF19 messenger RNA expression in LSCC tumor and paired adjacent samples. Small interfering RNA and short hairpin RNA were used to knockdown FGF19 in vitro and in vivo.

Results

FGF19 amplification was identified in a subset of LSCC patients (37.5%, 15/40), and upregulation of FGF19 expression was found in 60% (24/40) of tumor tissues compared to adjacent non‐tumorous tissues. Correlation analysis with clinicopathologic parameters showed that FGF19 upregulation was significantly associated with heavy smoking. Small interfering RNA knockdown of FGF19 led to the significant inhibition of cell growth and induced apoptosis in LSCC cells carrying the amplified FGF19 gene, but these effects was not observed in non‐amplified LSCC cells. Interfering FGF19 expression with short hairpin RNA also resulted in tumor growth inhibition and induced apoptosis in LSCC xenografts with amplified FGF19 in tumor cells.

Conclusion

Our results suggested that FGF19 signaling activation is required for cell growth and survival of FGF19 amplified LSCC cells, both in vitro and in vivo. Intervention of FGF19 activation could be a potential therapeutic strategy for LSCC patients with FGF19 amplification.

2-Aminopyrimidine Derivatives as New Selective Fibroblast Growth Factor Receptor 4 (FGFR4) Inhibitors

A series of 2-aminopyrimidine derivatives were designed and synthesized as highly selective FGFR4 inhibitors. One of the most promising compounds 2n tightly bound FGFR4 with a K_d value of 3.3 nM and potently inhibited its enzymatic activity with an IC₅₀ value of 2.6 nM, but completely spared FGFR1/2/3. The compound selectively suppressed proliferation of breast cancer cells harboring dysregulated FGFR4 signaling with an IC₅₀ value of 0.38 μM. Furthermore, 2n exhibited extraordinary target specificity in a Kinome-wide screen against 468 kinases, with S(35) and S(10) selectivity scores of 0.01 and 0.007 at 1.0 μM, respectively.

Association of Fibroblast Growth Factor Receptor 4 Genetic Polymorphisms With the Development of Uterine Cervical Cancer and Patient Prognosis

This is the first study to investigate the relationships among fibroblast growth factor receptor 4 (FGFR4) genetic polymorphisms, development of uterine cervical cancer, clinicopathological variables, and patient prognosis in Taiwanese women. Real-time polymerase chain reaction and genotyping were used to detect the genotype frequencies of 4 FGFR4 single-nucleotide polymorphisms (SNPs), rs351855 (C/T, Gly388Arg), rs2011077 (G/A), rs7708357 (G/A), and rs1966265 (Ile10Val), in 138 patients with invasive cancer, 89 with precancerous lesions of uterine cervix, and 335 normal controls. The results showed that there is no significant difference in the frequencies of FGFR4 SNPs rs351855, rs2011077, rs7708357, and 1966265 between women with cervical invasive cancer and normal controls even after controlling for age. However, significant differences existed in the distributions of the FGFR4 genetic polymorphism rs2011077, when mutant homozygotes (AA) were compared using other genotypes (GG/GA) as a reference, as well as rs1966265, when mutant homozygotes (AA) were compared using GG/GA as a reference, between women with cervical precancerous lesions and normal women even after controlling for age. In multivariate analysis, lymph node metastasis was associated with cancer recurrence, and lymph node metastasis and FGFR4 rs351855 were associated with patient survival. In conclusion, our study demonstrated that FGFR4 rs2011077 and rs1966265 are associated with the progression of cervical normal tissues to precancerous lesions in Taiwanese women. Moreover, rs351855 (Gly388Arg) is the only FGFR4 genetic polymorphism that is associated with patient survival.

Electrochemical sensor for rapid determination of fibroblast growth factor receptor 4 in raw cancer cell lysates

The first electrochemical immunosensor for the determination of fibroblast growth factor receptor 4 (FGFR4) biomarker is reported in this work. The biosensor involves a sandwich configuration with covalent immobilization of a specific capture antibody onto activated carboxylic-modified magnetic microcarriers (HOOC-MBs) and amperometric detection at disposable carbon screen-printed electrodes (SPCEs). The biosensor exhibits a great analytical performance regarding selectivity for the target protein and a low LOD of 48.2 pg mL^-1. The electrochemical platform was successfully applied for the determination of FGFR4 in different cancer cell lysates without any apparent matrix effect after a simple sample dilution and using only 2.5 μg of the raw lysate. Comparison of the results with those provided by a commercial ELISA kit shows competitive advantages by using the developed immunosensor in terms of simplicity, analysis time, and portability and cost-affordability of the required instrumentation for the accurate determination of FGFR4 in cell lysates.