Functional characterization of the ability of FGF8 to enhance porcine oocyte maturation.

Background: Fibroblast growth factor 19 (FGF19) and fibroblast growth factor receptor 4 (FGFR4) signaling play critical roles in hepatocarcinogenesis. This study explored the expression and clinical significance of FGF19/FGFR4 related signaling molecules in hepatocellular carcinoma (HCC). Method: We examined the mRNA expression of FGF19, FGFR4, klotho-beta (KLB), cyclin D1 (CCND1), and FGF4 in 151 surgically resected, primary unifocal HCC using quantitative real-time PCR analysis. The correlation of gene amplification and mRNA overexpression for FGF19 and FGF4 was investigated using a real-time PCR based copy number assay. FGF19 amplification was verified using fluorescence in situ hybridization. Univariate and multivariate analyses were performed to evaluate the prognostic value of these biomarkers for tumor recurrence and survival of patients. Results: Overexpression of FGF19, FGFR4, KLB, CCND1, and FGF4 mRNA was detected in 40%, 32%, 26%, 15%, and 35% of 151 tumors, respectively. In multivariate analyses, large tumor size (> 12.7 cm) and advanced tumor stage (stage ≥ II) independently predict worse patient survival. Using generalized additive models, we found mRNA expression of FGFR4 and KLB was significantly associated large tumor size (> 12.7 cm); mRNA expression of FGF19 and KLB was significantly associated advanced tumor stage (stage ≥ II). Furthermore, gene amplification of FGF19 and FGF4 significantly correlated to their mRNA overexpression (P = 0.006 for FGF19; P = 0.039 for FGF4). Conclusions: Overexpression of FGF19/FGFR4 related biomarkers is frequently found in HCC. Overexpression of FGF19 and FGF4 mRNA significantly correlates to their gene amplification. Expression status of FGFR4, KLB, and FGF19 may determine patient survival through their impact on tumor size (FGFR4 and KLB) and tumor stage (FGF19 and KLB). Citation Format: Zhong-Zhe Lin, Yung-Ming Jeng, Chiun Hsu, I-Lun Tsai, Kuan-Yu Chen, Fu-Chang Hu, Chih-Hung Hsu, Hey-Chi Hsu, Ann-Lii Cheng. Expression of FGF19/FGFR4 related biomarkers in hepatocellular carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3131.

BackgroundHepatocytes usually express fibroblast growth factor receptor 4 (FGFR4), but not its ligand, fibroblast growth factor 19 (FGF19). A subtype of hepatocellular carcinoma (HCC) expresses FGF19, which activates the FGFR4 signaling pathway that induces cell proliferation. FGFR4 inhibitors that target this mechanism are under clinical development for the treatment of HCCs with FGF19 amplification or FGFR4 overexpression. Src plays an essential role in the FGFR1 and FGFR2 signaling pathways. However, it is yet to be understood whether Src has any role in the FGF19-FGFR4 pathway in HCCs. In this study, we aimed to elucidate the role of Src in the FGF19-FGFR4 axis in HCC.Methods3 HCC cell lines expressing both FGF19 and FGFR4 were selected. The expression of each protein was suppressed by siRNA treatment, and the activity-regulating relationship between FGFR4 and Src was investigated by westernblot. Co-immunoprecipitation was performed using the FGFR4 antibody to identify the endosomal complex formation and receptor endocytosis. The intracellular migration pathways of the endosomal complex were observed by immuno-fluorescence and nuclear co-immunoprecipitation. Dasatinib and BLU9931 were used for cytotoxicity comparison.ResultsFGFR4 modulates the activity of Src and Src modulates the expression of FGFR4, showing a mutual regulatory relationship. FGFR4 activated by FGF19 formed an endosomal complex with Src and STAT3 and moved to the nucleus. However, when Src was suppressed, the formation of the endosomal complex was not observed. FGFR4 was released from the complex transferred into the nucleus and the binding of Src and STAT3 was maintained. Dasatinib showed cytotoxic results comparable to BLU9931. The results of our study demonstrated that Src is essential for the nuclear transport of STAT3, as it induces the endosomal delivery of FGFR4 in FGF19-expressing HCC cell lines.ConclusionsWe found that Src is essential for the endosomal delivery of the FGFR4 signaling complex in HCC. Our findings provide a scientific rationale for repurposing Src inhibitors for the treatment of HCCs in which the FGFR4 pathway is activated.

De novo bile acid synthesis in the liver needs to be tightly regulated in order to maintain optimal bile flow and prevent cholestasis. In the liver, fibroblast growth factor 19 (FGF19) regulates bile acid synthesis by down-regulating messenger RNA levels of cytochrome P450 7A1 (CYP7A1). FGF19 acts through fibroblast growth factor receptor 4 (FGFR4), and beta-Klotho has recently been recognized as a modulator of FGFR4 activity. However, its precise mechanism of action has not been thoroughly described. We show here that beta-Klotho is an endoplasmic reticulum-resident protein that affects the cellular abundance of different FGFR4 glycoforms. beta-Klotho binds and directs the core glycoform of FGFR4 to the proteasome, and it allows only a terminal glycoform to reach the plasma membrane. Only the terminal FGFR4 glycoform is phosphorylated upon FGF19 treatment of HepG2 cells, and this shows that only fully glycosylated FGFR4 is active in CYP7A1 down-regulation. beta-Klotho enhances FGF19 signaling by binding the inactive, core-glycosylated FGFR4 and preventing it from reaching the surface. These results indicate that beta-Klotho is an indirect regulator of FGFR4, whereas glycosylation is the master switch for FGF19 activity and regulation of bile acid synthesis.

Central FGF21 production regulates memory but not peripheral metabolism.

Global gene expression profiling has uncovered previously unrecognized subsets of human breast cancer, including the so-called "triple-negative" or "basal-like" tumours (BLBC) characterized by estrogen/progesterone receptor negativity, lack of Her-2/Neu amplification and high frequency of p53 mutation. These refractory tumours therefore are insensitive to hormonal therapy or trastuzumab-based therapy, and thus confer a markedly poor prognosis relative to other subtypes. To date, little progress has been made to identify specific molecular pathways associated with these refractory cancers that may be effectively targeted for therapeutic purposes. Using a human kinome RNAi library screen, we show that knock-down of endogenous human FGFR4 (but not FGFR1-3) induces significant tumor-specific cell death in basal-like breast cancer cells. Further analysis reveals that FGFR4 mediates the BLBC cells survival through activation of AKT as knock-down of endogenous FGFR4 in MDA-MB-468 and HCC1937 cells significantly reduced AKT phosphorylation. Consistently, ectopic expression of a constitutively active myristoylated AKT completely abrogates the apoptosis induced by FGFR4 knock-down. Interestingly, both MDA-MB-468 and HCC1937 also secrete fibroblast growth factor 19 (FGF19), a canonical ligand specific for FGFR4. RNAi-mediated silencing of FGF19 evidently suppresses the growth of these BLBC cells via AKT signalling as marked by diminished AKT phosphorylation following depletion of FGF19. Knockdown of FGF19 in addition triggers ERK1/2 activation to compensate for AKT signalling down-regulation in MDA-MB-468. Together, our results demonstrated the existence of a FGFR4-FGF19 autocrine loop which could potentially be developed as therapeutic target for future treatment of BLBC. Citation Format: Kai Hung Tiong, Boon Shing Tan, Heng Lungh Choo, Ammu Kutty Radhakrishnan, Rozita Rosli, Soon-Keng Cheong, Chee-Onn Leong. RNAi screening of human kinome identified fibroblast growth factor receptor 4 (FGFR4) as potential molecular target in basal-like breast cancers (BLBC). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1134. doi:10.1158/1538-7445.AM2013-1134

Hepatocellular carcinoma (HCC) accounts for 65% of all cases of liver cancers, ranking the 6th most common cancer and the 2nd cause of cancer mortality. HCC has more than 700,000 new cases/year and 600,000 deaths/year. Sorafenib is currently the standard of care for advanced disease, provides a response rate of ~2% and median survival <11 months. The fibroblast growth factor 19 (FGF19)-fibroblast growth factor receptor 4 (FGFR4)-Klotho β (KLB) signaling pathway regulates bile acid synthesis and is also a key driver in certain subtypes of HCC (around 30%). We generated BGS2219 and BGS2223 through FGFR4 structure-based design. BGS2219 and BGS223 are potent, selective and irreversible FGFR4 inhibitors. BGS2219 inhibits FGFR4 with an IC50 of 4nM and has greater than 2500 fold selectivity over FGFR1, 2 and 3. BG2219 took effects in both HCC and RMS tumor cell lines. In vivo administration of BG2219 was well tolerated in mice at all dosages with no body weight loss and and inhibited tumor growth in a dose -dependent fashion in HCC xenograft model. Complete tumor regression was observed at 40mg/kg. BGS2219 was tested in a combo therapy regimen with R1507 (anti-IGFR1 mab) in RMS (rhabdomyosarcoma) xenograft model in mice and showed that BG2219 plus R1507 significantly reduce the tumor volume in comparison with R1507 alone. BGS2223 is derived from BG2219, with improved oral bioavailability. BGS2223 has no hit in Cerep Screen safety panel and no activity detected in hERG assay at 10mM. In vivo oral administration of BG2223 in mice was well tolerated with no body weight loss and showed dose-dependent tumor growth inhibition in HCC CDX model at all dosages. Tumor regression was achieved at high dose treatment. BGS22 treatment in vivo in HCC tumor bearing mice caused alteration of CYP7A1 and FGF19 expression, which were utilized as biomarkers for FGFR4 inhibition. Citation Format: Hang Chen, Katherine Slemmons, Heather Ha, Robert Stanley, Qian Cai, Irene Yuan, Lee Helman, Ping Cao. Discovery of highly potent and selective covalent inhibitors of FGFR4 [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C072. doi:10.1158/1535-7163.TARG-19-C072

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and a deadly disease. Treatment options are limited and prognosis generally is poor. Aberrant signaling through the fibroblast growth factor 19 (FGF19) - fibroblast growth factor receptor 4 (FGFR4) axis has been implicated in the development of HCC, and recently FGF19 has been determined as a specific driver gene amplification in a subset of liver tumors and cancer cell lines. Here, we describe the cellular and in vivo profile of NVP-FGF401, a highly potent and selective, first in class, reversible-covalent small-molecule inhibitor of the kinase activity of FGFR4. NVP-FGF401 is exquisitely selective for FGFR4 versus other FGFR family members and all other kinases. We show that among the FGF19-amplified liver cancer cells in the cancer cell line encyclopedia (CCLE), only those with concomitant expression of β-klotho (KLB), a co-receptor for FGF19 that facilitates its binding to FGFR4, are sensitive to NVP-FGF401. NVP-FGF401 has good oral PK properties and shows an excellent in vivo PK/PD relationship. NVP-FGF401 has remarkable anti-tumor activity in mice bearing HCC tumor xenografts and PDX models that are positive for FGF19, FGFR4 and KLB. NVP-FGF401 is the first FGFR4 inhibitor to enter clinical trials, and a PhI/II study is currently ongoing in HCC and other types of solid tumors. Citation Format: Andreas Weiss, Diana Graus Porta, Flavia Reimann, Alexandra Buhles, Christelle Stamm, Robin A. Fairhurst, Jacqueline Kinyamu-Akunda, Dario Sterker, Masato Murakami, Markus Wartmann, Youzhen Wang, Jeffrey A. Engelman, Francesco Hofmann, Wiliam R. Sellers. NVP-FGF401: Cellular and in vivo profile of a novel highly potent and selective FGFR4 inhibitor for the treatment of FGF19/FGFR4/KLB+ tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2103. doi:10.1158/1538-7445.AM2017-2103

The poor prognosis of patients with hepatocellular carcinoma (HCC) is mainly attributed to its high rate of metastasis and recurrence. However, the molecular mechanisms underlying HCC metastasis need to be elucidated. The SRY-related high-mobility group box (SOX) family proteins, which are a group of highly conserved transcription factors, play important roles in cancer initiation and progression. Here, we report on a role of SOX18, a member of the SOX family, in promoting HCC invasion and metastasis. The elevated expression of SOX18 was positively correlated with poor tumor differentiation, higher tumor-node-metastasis (TNM) stage, and poor prognosis. Overexpression of SOX18 promoted HCC metastasis by up-regulating metastasis-related genes, including fibroblast growth factor receptor 4 (FGFR4) and fms-related tyrosine kinase 4 (FLT4). Knockdown of both FGFR4 and FLT4 significantly decreased SOX18-mediated HCC invasion and metastasis, whereas the stable overexpression of FGFR4 and FLT4 reversed the decrease in cell invasion and metastasis that was induced by inhibition of SOX18. Fibroblast growth factor 19 (FGF19), which is the ligand of FGFR4, up-regulated SOX18 expression. A mechanistic investigation indicated that the up-regulation of SOX18 that was mediated by the FGF19-FGFR4 pathway relied on the phosphorylated (p)-fibroblast growth factor receptor substrate 2/p-glycogen synthase kinase 3 beta/β-catenin pathway. SOX18 knockdown significantly reduced FGF19-enhanced HCC invasion and metastasis. Furthermore, BLU9931, a specific FGFR4 inhibitor, significantly reduced SOX18-mediated HCC invasion and metastasis. In human HCC tissues, SOX18 expression was positively correlated with FGF19, FGFR4, and FLT4 expression, and patients that coexpressed FGF19/SOX18, SOX18/FGFR4, or SOX18/FLT4 had the worst prognosis. We defined a FGF19-SOX18-FGFR4 positive feedback loop that played a pivotal role in HCC metastasis, and targeting this pathway may be a promising therapeutic option for the clinical management of HCC.

The fibroblast growth factor 19 (FGF19)/fibroblast growth factor receptor 4 (FGFR4) signaling pathways play critical roles in a variety of cancers, such as hepatocellular carcinoma (HCC). FGFR4 is recognized as a promising target to treat HCC. Currently, all FGFR covalent inhibitors target one of the two cysteines (Cys477 and Cys552). Here, we designed and synthesized a dual-warhead covalent FGFR4 inhibitor, CXF-009, targeting Cys477 and Cys552 of FGFR4. We report the cocrystal structure of FGFR4 with CXF-009, which exhibits a dual-warhead covalent binding mode. CXF-009 exhibited stronger selectivity for FGFR4 than FGFR1-3 and other kinases. CXF-009 can also potently inhibit the single cystine mutants, FGFR4(C477A) and FGFR4(C552A), of FGFR4. In summary, our study provides a dual-warhead covalent FGFR4 inhibitor that can covalently target two cysteines of FGFR4. CXF-009, to our knowledge, is the first reported inhibitor that forms dual-warhead covalent bonds with two cysteine residues in FGFR4. CXF-009 also has the potential to overcome drug induced resistant FGFR4 mutations and might serve as a lead compound for future anticancer drug discovery.

Fibroblast growth factor receptor4(FGFR4) has been confirmed to be associated with the progression and prognosis of ovarian cancer, while the underlying mechanism has not been well elucidated and the clinical significance of its ligand, fibroblast growth factor19 (FGF19), has not been explored. To study the clinical significance of FGF19 in advanced‑stage serous ovarian cancer, we detected the expression of FGF19 and FGFR4 by immunohistochemistry (IHC), evaluated the correlation between FGF19 and clinicopathological factors by Chi-square(χ2)test, and analyzed the association between FGF19, FGFR4 and the overall survival rate using the Kaplan‑Meier method. As a result, we demonstrated that high expression of FGF19 and FGFR4 both predicted unfavorable prognosis (P=0.033 and 0.018, respectively), whereas FGF19-FGFR4 double high expression was a more sensitive prognostic factor of advanced-stage serous ovarian cancer (P<0.001). With experiments invitro, we demonstrated that both recombinant FGF19 and secreted FGF19 promoted ovarian cancer proliferation and invasion by activating FGFR4 and the subsequent AKT-MAPK signaling pathway, suggesting that FGF19-FGFR4 signaling may auto-activate in a paracrine or autocrine manner. In conclusion, FGF19-FGFR4 double high expression was a more sensitive prognostic factor than FGF19 or FGFR4 alone in advanced-stage serous ovarian cancer. The FGF19-FGFR4 signaling pathway can promote ovarian cancer proliferation and invasion by the AKT-MAPK signaling pathway, indicating that FGF19 could be a potential therapeutic drug target of advanced-stage serous ovarian cancer.

Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality globally, with limited therapeutic progress for advanced stages. The aberrant fibroblast growth factor 19 (FGF19)-fibroblast growth factor receptor 4 (FGFR4) axis promotes oncogenesis and is linked to targeted-immunotherapy of HCC. Multi-kinase inhibitors (MKIs) enhance anti-tumor effects by targeting this axis and FGF19 overexpression upregulates programmed cell death ligand 1 in tumor microenvironment. Clinical studies have demonstrated the efficacy of selective FGFR4 inhibitors in HCC treatment, with enhanced anti-tumor effects when combined with MKIs or immune checkpoint inhibitors. Phase I clinical trials of Irpagratinib (ABSK-011) demonstrated an objective response rate of 43.5%, which increased to 55.6% combined with atezolizumab. FGF19 also serves as a biomarker for HCC. This review systematically summarizes the literature retrieved from PubMed and other databases using search terms “HCC”, “fibroblast growth factor 19”, “fibroblast growth factor receptor 4”, “FGFR4 inhibitor”, “targeted therapy”, “multi-kinase inhibitor”, “immunotherapy”, “immune checkpoint inhibitor”, and “biomarker”. It also firstly synthesizes combination strategies and underlying mechanisms between FGFR4 inhibitors and targeted-immunotherapy, addressing critical gaps in existing reviews. Additionally, we discuss the potential of FGF19 as a predictive biomarker, integrating mechanistic and clinical evidence to advance precision HCC therapeutics.

Fibroblast growth factor 19 (FGF19) and fibroblast growth factor receptor 4 (FGFR4) signalling play critical roles in hepatocarcinogenesis. This study explored the potential of FGF19- and FGFR4-related biomarkers in predicting early tumour recurrence (ETR) and survival in patients with resectable hepatocellular carcinoma (HCC). We examined the mRNA expressions of FGF19, FGFR4, klotho-beta (KLB), cyclin D1 (CCND1) and FGF4 in 151 surgically resected, primary unifocal HCCs through quantitative real-time polymerase chain reaction. Generalized additive models were fitted to detect nonlinear effects of continuous covariates and define thresholds of biomarker expressions. Univariate and multivariate analyses were performed to evaluate prognostic values of these biomarkers for tumour recurrence and patient survival. Overexpression of FGF19, FGFR4, KLB, CCND1 and FGF4 mRNA was detected in 40%, 32%, 26%, 15% and 35% of 151 tumours respectively. ETR was the strongest prognostic factor predicting worse overall survival (hazard ratio [HR], 5.678; 95% confidence interval, 3.7-8.713; P<0.001). Furthermore, we revealed that mRNA expression levels of KLB (HR, 3.857; P=0.021) and FGF19 (HR, 3.248; P=0.017) were significantly associated with the occurrence of ETR. Frequent overexpression of FGF19/FGFR4-related biomarkers was detected in resectable HCC. Expression levels of KLB and FGF19 may determine patient survival outcomes through their effects on ETR.

The Hippo pathway is involved in the proliferation of intrafollicular cells and in early embryonic development, mainly because effectors of this pathway are key transcription regulators of genes such as CTGF and CYR61, which are involved in cell proliferation. Recent studies by our group found that fibroblast growth factor 18 (FGF18) is present in the fallopian tube during early embryonic development, leading to the hypothesis that FGF18 may have a role during embryonic development. Therefore, the aim of the following study was to determine whether FGF18 modulates the expression of Hippo pathway target genes, CTGF and CYR61, during oocyte maturation and early embryonic development. Three experiments were carried out, with in vitro maturation (IVM) of cumulus-oocyte complexes (COCs) and embryo culture. In experiment one, FGF18 (100 ng/ml) induced an increase (P < 0.05) in CTGF gene expression at 12 h post-exposure. In experiment two, FGF18 (100 ng/ml) induced a reduction (P < 0.05) in CTGF expression at 3 h post-exposure. In the third experiment, day 7 embryos exposed to FGF18 during oocyte IVM expressed greater CTGF mRNA abundance, whereas FGF18 exposure during embryo in vitro embryo culture did not alter CTGF expression in comparison with untreated controls. The preliminary data presented here show that FGF18 modulates CTGF expression in critical periods of oocyte nuclear maturation, cumulus expansion and early embryonic development in cattle.

Fibroblast Growth Factor 19 (FGF19) is a member of the Fibroblast Growth Factor (FGF) family, known for its role in various cellular processes including embryonic development and metabolic regulation. FGF19 functions as an endocrine factor, influencing energy balance, bile acid synthesis, glucose and lipid metabolism, as well as cell proliferation. FGF19 has a conserved structure typical of FGFs but exhibits unique features. Unlike most FGFs, which act locally, FGF19 travels through the bloodstream to distant targets including the liver. Its interaction with the β-Klotho (KLB) co-receptor and FGF Receptor 4 (FGFR4) in hepatocytes or FGFR1c in extrahepatic tissues initiates signaling cascades crucial for its biological functions. Although the mouse ortholog, FGF15, diverges significantly from human FGF19 in protein sequence and receptor binding, studies of FGF15-deficient mice have led to a better understanding of the proteins’ role in bile acid regulation, metabolism, and embryonic development. Overexpression studies in transgenic mice have further revealed roles in not only ameliorating metabolic diseases but also in promoting hepatocyte proliferation and tumorigenesis. This review summarizes the gene and protein structure of FGF19/15, its expression patterns, phenotypes in mutant models, and implication in human diseases, providing insights into potential therapeutic strategies targeting the FGF19 signaling pathway.

Oocyte-secreted factors (OSFs) regulate differentiation of cumulus cells and are of pivotal relevance for fertility. Bone morphogenetic protein 15 (BMP15) and fibroblast growth factor 10 (FGF10) are OSFs and enhance oocyte competence by unknown mechanisms. We tested the hypothesis that BMP15 and FGF10, alone or combined in the maturation medium, enhance cumulus expansion and expression of genes in the preovulatory cascade and regulate glucose metabolism favouring hyaluronic acid production in bovine cumulus-oocyte complexes (COCs). BMP15 or FGF10 increased the percentage of fully expanded COCs, but the combination did not further stimulate it. BMP15 increased cumulus cell levels of mRNA encoding a disintegrin and metalloprotease 10 (ADAM10), ADAM17, amphiregulin (AREG), and epiregulin (EREG) at 12 h of culture and of prostaglandin (PG)-endoperoxide synthase 2 (PTGS2), pentraxin 3 (PTX3) and tumor necrosis factor alpha-induced protein 6 (TNFAIP6 (TSG6)) at 22 h of culture. FGF10 did not alter the expression of epidermal growth factor-like factors but enhanced the mRNA expression of PTGS2 at 4 h, PTX3 at 12 h, and TNFAIP6 at 22 h. FGF10 and BMP15 stimulated glucose consumption by cumulus cells but did not affect lactate production or levels of mRNA encoding glycolytic enzymes phosphofructokinase and lactate dehydrogenase A. Each growth factor increased mRNA encoding glucosamine:fructose-6-PO4 transaminases, key enzymes in the hexosamine pathway leading to hyaluronic acid production, and BMP15 also stimulated hyaluronan synthase 2 (HAS2) mRNA expression. This study provides evidence that BMP15 and FGF10 stimulate expansion of in vitro-matured bovine COCs by driving glucose metabolism toward hyaluronic acid production and controlling the expression of genes in the ovulatory cascade, the first acting upon ADAM10, ADAM17, AREG, and EREG and the second on downstream genes, particularly PTGS2.