Expression of FGF8, FGF18, and FGFR4 in Gastroesophageal Adenocarcinomas

FGF18 impairs blastocyst viability, DNA double-strand breaks and maternal recognition of pregnancy genes

Embryonic mortality in cattle is high, reaching 10-40 % in vivo and 60-70 % in vitro. Death of embryos involves reduced expression of genes related to embryonic viability, inhibition of DNA repair and increased DNA damage. In follicular granulosa cells, FGF18 from the theca layer increases apoptosis and DNA damage, so we hypothesized that FGF18 may also affect the oocyte and contribute to early embryonic death. The aims of this study were to identify the effects of FGF18 on cumulus expansion, oocyte maturation and embryo development from cleavage to blastocyst stage using a conventional bovine in vitro embryo production system using ovaries of abattoir origin. Addition of FGF18 during in-vitro maturation did not affect FSH-induced cumulus expansion or rates of nuclear maturation. When FGF18 was present in the culture system, rates of cleavage were not affected however, blastocyst and expanded blastocyst development was substantially inhibited (P < 0.05), indicating a delay of blastulation. The number of phosphorylated histone H2AFX foci per nucleus, a marker of DNA damage, was higher in cleavage-stage embryos cultured with FGF18 than in those from control group (P < 0.05). Furthermore, FGF18 decreased accumulation of PTGS2 and IFNT2 mRNA in blastocysts. In conclusion, these novel findings suggest that FGF18 plays a role in the regulation of embryonic death during the early stages of development by impairing DNA double-strand break repair and expression of genes associated with embryo viability and maternal recognition of pregnancy during the progression from oocyte to expanded blastocysts.

Circulating FGF18 is decreased in pleural mesothelioma but not correlated with disease prognosis

BACKGROUND

Pleural mesothelioma (PM) is a relatively rare malignancy with limited treatment options and dismal prognosis. We have previously found elevated FGF18 expression in PM tissue specimens compared with normal mesothelium. The objective of the current study was to further explore the role of FGF18 in PM and evaluate its suitability as a circulating biomarker.

METHODS

FGF18 mRNA expression was analyzed by real-time PCR in cell lines and in silico in datasets from the Cancer Genome Atlas (TCGA). Cell lines overexpressing FGF18 were generated by retroviral transduction and cell behavior was investigated by clonogenic growth and transwell assays. Plasma was collected from 40 PM patients, six patients with pleural fibrosis, and 40 healthy controls. Circulating FGF18 was measured by ELISA and correlated to clinicopathological parameters.

RESULTS

FGF18 showed high mRNA expression in PM and PM-derived cell lines. PM patients with high FGF18 mRNA expression showed a trend toward longer overall survival (OS) in the TCGA dataset. In PM cells with low endogenous FGF18 expression, forced overexpression of FGF18 resulted in reduced growth but increased migration. Surprisingly, despite the high FGF18 mRNA levels observed in PM, circulating FGF18 protein was significantly lower in PM patients and patients with pleural fibrosis than in healthy controls. No significant association of circulating FGF18 with OS or other disease parameters of PM patients was observed.

CONCLUSIONS

FGF18 is not a prognostic biomarker in PM. Its role in PM tumor biology and the clinical significance of decreased plasma FGF18 in PM patients warrant further investigation.

The role of fibroblast growth factor 18 in cancers: functions and signaling pathways

Fibroblast growth factor 18(FGF18) is a member of the fibroblast growth factor family (FGFs). FGF18 is a class of bioactive substances that can conduct biological signals, regulate cell growth, participate in tissue repair and other functions, and can promote the occurrence and development of different types of malignant tumors through various mechanisms. In this review, we focus on recent studies of FGF18 in the diagnosis, treatment, and prognosis of tumors in digestive, reproductive, urinary, respiratory, motor, and pediatric systems. These findings suggest that FGF18 may play an increasingly important role in the clinical evaluation of these malignancies. Overall, FGF18 can function as an important oncogene at different gene and protein levels, and can be used as a potential new therapeutic target and prognostic biomarker for these tumors.

miR-6742-5p regulates the invasion and migration of lung adenocarcinoma cells via mediating FGF8/ERK12/MMP9/MMP2 signaling pathway

BACKGROUND

microRNAs (miRNAs) are involved in the progression of Lung adenocarcinoma (LUAD), however, the functions of miR-6742-5p in LUAD remains unknown, thereby this study was carried on.

METHODS

The mRNA and miRNA expression data from the LUAD and normal control were obtained from Gene Expression Omnibus (GEO) database, TargetScan and mirDIP were applied to predict the relationship between miR-6742-5p and FGF8.Q-PCR, western blot, dual-luciferase, wound Healing and transwell assays were performed to test the functions of miR-6742-5p in LUAD.

RESULTS

Bioinformatics analysis and dual-luciferase identified FGF8 is the target-gene of miR-6742-5p, which is declined in LUAD of human tissues and cell lines, and miR-6742-5P OE suppressed the progression of LUAD in nude mice. MiR-6742-5p OE and KD suppressed or increased the abilities of LUAD' metastasis tested by wound healing and transwell assays H522 and PC-9 cells, these effects about miR-6742-5p OE were reversed by FGF8; miR-6742-5p OE, KD inhibited and increased the expression of FGF8 as its downstream p-ERK1/2, MMP-2/-9, these results were corrected by ERK1/2 inhibitor: Ro 67-7476; the miR-6742-5p KD increased the migrated and invaded cells and suppressed by MMPs inhibitor: S3304. These results identified the negative correlation of miR-6742-5p with FGF8-ERK1/2 signal pathway in LUAD progression.

CONCLUSIONS

We conclude that miR-6742-5p might be a regulator of LUAD progression by targeting FGF8/ERK1/2/MMPs signaling pathway, which provides a novel therapeutic target for LUAD.

Investigation of the Proliferative Potential of FGF21 or FGF19 in Liver-Specific FGFR4-Deficient Mice

Fibroblast growth factor 21 (FGF21) and FGF15/FGF19 belong to the same subgroup of FGFs and are believed to have therapeutic potential in the treatment of type 2 diabetes and associated metabolic dysfunctionalities and pathological conditions. FGF19 has been proposed to induce hyperplasia and liver tumors in FVB mice (named after its susceptibility to Friend leukemia virus B), mediated by the FGF receptor 4 (FGFR4). The goal of this work was to investigate whether FGF21 might also have a potential proliferative effect mediated via FGFR4 using liver-specific Fgfr4 knockout (KO) mice. We conducted a mechanistic 7-day study involving female Fgfr4 fl/fl and Fgfr4 KO mice with a treatment regimen of twice daily or daily subcutaneous injections of FGF21 or FGF19 (positive control), respectively. The Ki-67 liver labeling index (LI) was evaluated by a semi-automated bioimaging analysis. The results showed a statistically significant increase in FGF21- and FGF19-treated Fgfr4 fl/fl mice. Interestingly, in Fgfr4 KO mice, this effect was absent following both treatments of FGF19 and FGF21, indicating that not only the FGFR4 receptor is pivotal for the mediation of hepatocellular proliferation by FGF19 leading finally to liver tumors but it seems also that FGFR4/FGF21 signaling has an impact on the hepatocellular proliferative activity, which does not promote the formation of hepatocellular liver tumors based on the current knowledge.

The Alterations and Roles of Glycosaminoglycans in Human Diseases

Glycosaminoglycans (GAGs) are a heterogeneous family of linear polysaccharides which are composed of a repeating disaccharide unit. They are also linked to core proteins to form proteoglycans (PGs). GAGs/PGs are major components of the cell surface and the extracellular matrix (ECM), and they display critical roles in development, normal function, and damage response in the body. Some properties (such as expression quantity, molecular weight, and sulfation pattern) of GAGs may be altered under pathological conditions. Due to the close connection between these properties and the function of GAGs/PGs, the alterations are often associated with enormous changes in the physiological/pathological status of cells and organs. Therefore, these GAGs/PGs may serve as marker molecules of disease. This review aimed to investigate the structural alterations and roles of GAGs/PGs in a range of diseases, such as atherosclerosis, cancer, diabetes, neurodegenerative disease, and virus infection. It is hoped to provide a reference for disease diagnosis, monitoring, prognosis, and drug development.

Immunoreactivity against fibroblast growth factor 8 in alveolar rhabdomyosarcoma patients and its involvement in tumor aggressiveness

Rhabdomyosarcoma (RMS) is an aggressive pediatric soft tissue sarcoma characterized by a very poor prognosis when relapses occur after front-line therapy. Therefore, a major challenge for patients’ management remains the identification of markers associated with refractory and progressive disease. In this context, cancer autoantibodies are natural markers of disease onset and progression, useful to unveil novel therapeutic targets. Herein, we matched autoantibody profiling of alveolar RMS (ARMS) patients with genes under regulatory control of PAX3-FOXO1 transcription factor and revealed fibroblast growth factor 8 (FGF8) as a novel ARMS tumor antigen of diagnostic, prognostic, and therapeutic potential. We demonstrated that high levels of FGF8 autoantibodies distinguished ARMS patients from healthy subjects and represented an independent prognostic factor of better event-free survival. FGF8 was overexpressed in ARMS tumors compared to other types of pediatric soft tissue sarcomas, acting as a positive regulator of cell signaling. Indeed, FGF8 was capable of stimulating ARMS cells migration and expression of pro-angiogenic and metastasis-related factors, throughout MAPK signaling activation. Of note, FGF8 was found to increase in recurrent tumors, independently of PAX3-FOXO1 expression dynamics. Risk of recurrence correlated positively with FGF8 expression levels at diagnosis and reduced FGF8 autoantibodies titer, almost as if to suggest a failure of the immune response to control tumor growth in recurring patients. This study provides evidence about the crucial role of FGF8 in ARMS and the protective function of natural autoantibodies, giving new insights into ARMS biology and laying the foundations for the development of new therapeutic strategies.

FGFR4 inhibitors for the treatment of hepatocellular carcinoma: a synopsis of therapeutic potential

INTRODUCTION

The mainstay pharmacological approaches to patients with hepatocellular carcinoma (HCC) are tyrosine kinase inhibitors, antiangiogenic agents, and immune checkpoint inhibitors in combination therapy. Aberrant signaling of fibroblast growth factor 19 (FGF19) and its corresponding receptor, fibroblast growth factor receptor 4 (FGFR4), are a driver of HCC cell growth and survival. However, the clinical potential of agents targeting aberrant FGF19/FGFR4 signaling has not been adequately explored.

AREAS COVERED

We evaluate the existing literature on aberrant signaling of FGF19/FGFR4 in HCC and address the recent preclinical and clinical advances of selective FGFR4 inhibitors in the treatment of advanced HCC. Our literature search was performed in September 2021 on clinical trials and ongoing studies published in journals or presented in conferences for cancer research.

EXPERT OPINION

Preclinical studies show selective FGFR4 inhibitors to be highly potent. These inhibitors also show promise in clinical trials and demonstrate manageable on-target side effects. An emphasis should be placed on the development of predictive biomarkers and on enhancing the understanding of primary and acquired resistance mechanisms. This will inspire rationale combination therapy strategies for testing in future clinical trials.

Advances of Fibroblast Growth Factor/Receptor Signaling Pathway in Hepatocellular Carcinoma and its Pharmacotherapeutic Targets

Hepatocellular carcinoma (HCC) is a type of primary liver cancer with poor prognosis, and its incidence and mortality rate are increasing worldwide. It is refractory to conventional chemotherapy and radiotherapy owing to its high tumor heterogeneity. Accumulated genetic alterations and aberrant cell signaling pathway have been characterized in HCC. The fibroblast growth factor (FGF) family and their receptors (FGFRs) are involved in diverse biological activities, including embryonic development, proliferation, differentiation, survival, angiogenesis, and migration, etc. Data mining results of The Cancer Genome Atlas demonstrate high levels of FGF and/or FGFR expression in HCC tumors compared with normal tissues. Moreover, substantial evidence indicates that the FGF/FGFR signaling axis plays an important role in various mechanisms that contribute to HCC development. At present, several inhibitors targeting FGF/FGFR, such as multikinase inhibitors, specific FGFR4 inhibitors, and FGF ligand traps, exhibit antitumor activity in preclinical or early development phases in HCC. In this review, we summarize the research progress regarding the molecular implications of FGF/FGFR-mediated signaling and the development of FGFR-targeted therapeutics in hepatocarcinogenesis.

FGF/FGFR Signaling in Hepatocellular Carcinoma: From Carcinogenesis to Recent Therapeutic Intervention

Simple Summary

As the most common primary liver cancer, HCC is a tricky cancer resistant to systemic therapies. The fibroblast growth factor family and its receptors are gaining more and more attention in various cancers. Noticing an explosion in the number of studies about aberrant FGF/FGFR signaling in HCC being studied, we were encouraged to summarize them. This review discusses how FGF/FGFR signaling influences HCC development and its implications in HCC prediction and target treatment, and combination treatment.

Abstract

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, ranking third in cancer deaths worldwide. Over the last decade, several studies have emphasized the development of tyrosine kinase inhibitors (TKIs) to target the aberrant pathways in HCC. However, the outcomes are far from satisfactory due to the increasing resistance and adverse effects. The family of fibroblast growth factor (FGF) and its receptors (FGFR) are involved in various biological processes, including embryogenesis, morphogenesis, wound repair, and cell growth. The aberrant FGF/FGFR signaling is also observed in multiple cancers, including HCC. Anti-FGF/FGFR provides delightful benefits for cancer patients, especially those with FGF signaling alteration. More and more multi-kinase inhibitors targeting FGF signaling, pan-FGFR inhibitors, and selective FGFR inhibitors are now under preclinical and clinical investigation. This review summarizes the aberrant FGF/FGFR signaling in HCC initiating, development and treatment status, and provide new insights into the treatment of HCC.

Fibroblast growth factor 8 overexpression is predictive of poor prognosis in pancreatic ductal adenocarcinoma

Background

Despite distinctive advances in the field of pancreatic cancer therapy over the past few years, patient survival remains poor. Fibroblast growth factors 8 (FGF8) and 18 (FGF18) both play a role in modulating the activity of malignant cells and have been identified as promising biomarkers in a number of cancers. However, no data exist on the expression of FGF8 and FGF18 in pancreatic ductal adenocarcinoma (PDAC).

Methods

Protein expression levels of FGF8 and FGF18 in postoperative specimens of neoadjuvantly treated and primarily resected patients were investigated using immunohistochemistry. Immunostaining scores were calculated as the products of the staining intensity and the staining rate. Scores exceeding the median score were considered as high expression.

Results

Specimens from 78 patients with PDAC were available and met the eligibility criteria for analysis of protein expression using immunohistochemistry. 15 (19.2%) patients had received neoadjuvant chemotherapy. High protein levels of FGF8 and FGF18 were detected in 40 (51.8%) and 33 (42.3%) patients, respectively. Kaplan–Meier analysis demonstrated significantly shorter overall survival in patients with high expression of FGF8 (p = 0.04). Multivariable Cox proportional hazard regression models revealed that high expression of FGF8 (Hazard ratio [HR] 0.53, 95% Confidence interval [CI] 0.32–0.89, p = 0.016) was an independent prognostic factor for diminished overall survival in patients with PDAC. By contrast, no statistical significance was found for FGF18 overexpression. In addition, the FGF8 protein level correlated with the factor resection margin (p = 0.042).

Conclusion

FGF8 is a promising target for new anticancer therapies using FGF inhibitors in pancreatic ductal adenocarcinomas.

Post-transcriptional regulation of BRG1 by FIRΔexon2 in gastric cancer

Brahma-related gene 1 (BRG1), an ATPase subunit of the SWItch/sucrose non-fermentable (SWI/SNF) chromatin remodeling complex controls multipotent neural crest formation by regulating epithelial-mesenchymal transition (EMT)-related genes with adenosine triphosphate-dependent chromodomain-helicase DNA-binding protein 7 (CHD7). The expression of BRG1 engages in pre-mRNA splicing through interacting RNPs in cancers; however, the detailed molecular pathology of how BRG1and CHD7 relate to cancer development remains largely unveiled. This study demonstrated novel post-transcriptional regulation of BRG1 in EMT and relationship with FIRΔexon2, which is a splicing variant of the far-upstream element-binding protein (FUBP) 1-interacting repressor (FIR) lacking exon 2, which fails to repress c-myc transcription in cancers. Previously, we have reported that FIR complete knockout mice (FIR^-/-) was embryonic lethal before E9.5, suggesting FIR is crucial for development. FIRΔexon2 acetylated H3K27 on promoter of BRG1 by CHIP-sequence and suppressed BRG1 expression post-transcriptionally; herein BRG1 suppressed Snai1 that is a transcriptional suppressor of E-cadherin that prevents cancer invasion and metastasis. Ribosomal proteins, hnRNPs, splicing-related factors, poly (A) binding proteins, mRNA-binding proteins, tRNA, DEAD box, and WD-repeat proteins were identified as co-immunoprecipitated proteins with FIR and FIRΔexon2 by redoing exhaustive mass spectrometry analysis. Furthermore, the effect of FIRΔexon2 on FGF8 mRNA splicing was examined as an indicator of neural development due to impaired CHD7 revealed in CHARGE syndrome. Expectedly, siRNA of FIRΔexon2 altered FGF8 pre-mRNA splicing, indicated close molecular interaction among FIRΔexon2, BRG1 and CHD7. FIRΔexon2 mRNA was elevated in human gastric cancers but not in non-invasive gastric tumors in FIR^+/ mice (K19-Wnt1/C2mE x FIR^+/-). The levels of FIR family (FIR, FIRΔexon2 and PUF60), BRG1, Snai1, FBW7, E-cadherin, c-Myc, cyclin-E, and SAP155 increased in the gastric tumors in FIR^+/- mice compared to those expressed in wild-type mice. FIR family, Snai1, cyclin-E, BRG1, and c-Myc showed trends toward higher expression in larger tumors than in smaller tumors in Gan-mice (K19-Wnt1/C2mE). The expressions of BRG1 and Snai1 were positively correlated in the gastric tumors of the Gan-mice. Finally, BRG1 is a candidate substrate of F-box and WD-repeat domain-containing 7 (FBW7) revealed by three-dimensional crystal structure analysis that the U2AF-homology motif (UHM) of FIRΔexon2 interacted with tryptophan-425 and asparate-399 (WD)-like motif in the degron pocket of FBW7 as a UHM-ligand motif. Together, FIRΔexon2 engages in multi-step post-transcriptional regulation of BRG1, affecting EMT through the BRG1/Snai1/E-cadherin pathway and promoting tumor proliferation and invasion of gastric cancers.