Cellular signaling by fibroblast growth factor receptors

Ferroptosis is induced by lenvatinib through fibroblast growth factor receptor-4 inhibition in hepatocellular carcinoma

The tyrosine kinase inhibitor lenvatinib is used to treat advanced hepatocellular carcinoma (HCC). Ferroptosis is a type of cell death characterized by the iron‐dependent accumulation of lethal lipid reactive oxygen species (ROS). Nuclear factor erythroid‐derived 2‐like 2 (Nrf2) protects HCC cells against ferroptosis. However, the mechanism of lenvatinib‐induced cytotoxicity and the relationships between lenvatinib resistance and Nrf2 are unclear. Thus, we investigated the relationship between lenvatinib and ferroptosis and clarified the involvement of Nrf2 in lenvatinib‐induced cytotoxicity. Cell viability, lipid ROS levels, and protein expression were measured using Hep3B and HuH7 cells treated with lenvatinib or erastin. We examined these variables after silencing fibroblast growth factor receptor‐4 (FGFR4) or Nrf2 and overexpressing‐Nrf2. We immunohistochemically evaluated FGFR4 expression in recurrent lesions after resection and clarified the relationship between FGFR4 expression and lenvatinib efficacy. Lenvatinib suppressed system X_c⁻ (xCT) and glutathione peroxidase 4 (GPX4) expression. Inhibition of the cystine import activity of xCT and GPX4 resulted in the accumulation of lipid ROS. Silencing‐FGFR4 suppressed xCT and GPX4 expression and increased lipid ROS levels. Nrf2‐silenced HCC cells displayed sensitivity to lenvatinib and high lipid ROS levels. In contrast, Nrf2‐overexpressing HCC cells displayed resistance to lenvatinib and low lipid ROS levels. The efficacy of lenvatinib was significantly lower in recurrent HCC lesions with low‐FGFR4 expression than in those with high‐FGFR4 expression. Patients with FGFR4‐positive HCC displayed significantly longer progression‐free survival than those with FGFR4‐negative HCC. Lenvatinib induced ferroptosis by inhibiting FGFR4. Nrf2 is involved in the sensitivity of HCC to lenvatinib.

Basic fibroblast growth factor uniquely stimulates quiescent vascular smooth muscle cells and induces proliferation and dedifferentiation

Blood vessels normally remain stable over the long-term. However, in atherosclerosis, vascular cells leave the quiescent state and enter an activated state. Here, we investigated the factors that trigger breakage of the quiescent state by screening growth factors and cytokines using a vascular smooth muscle cell (SMC) line and an endothelial cell (EC) line. Despite known functions of the tested factors, only basic fibroblast growth factor (bFGF) was identified as a potent trigger of quiescence breakage in SMCs, but not ECs. bFGF disrupted tight SMC-monolayers, and caused morphological changes, proliferation and dedifferentiation. Human primary SMCs, but not ECs, also showed similar results. Aberrant SMC-proliferation is a critical histological event in atherosclerosis. We thus provide further insights into the role of bFGF in vascular pathobiology.

Nuclear Localization of Fibroblast Growth Factor Receptor 1 in Breast Cancer Cells Interacting with Cancer Associated Fibroblasts

Cancer-associated fibroblasts (CAFs) represent a major component of the tumor microenvironment and interplay with cancer cells by secreting cytokines, growth factors and extracellular matrix proteins. When estrogen receptor-negative breast cancer MDA-MB-231 cells were treated with the CAF-conditioned medium (CAF-CM), Akt and STAT3 involved in cell proliferation and survival were activated through phosphorylation. CAFs secrete fibroblast growth factor 2 (FGF2), thereby stimulating breast cancer cell progression. Akt activation induced by CAF-CM in MDA-MB-231 cells was abolished when FGF2-neutralizing antibody was added. Treatment of MDA-MB-231 cells directly with FGF2 enhanced the phosphorylation of Akt and the FGF receptor (FGFR) substrate, FRS2α. These events were abrogated by siRNA-mediated silencing of FGFR1. In a xenograft mouse model, co-injection of MDA-MB-231 cells with activated fibroblasts expressing FGF2 dramatically enhanced activation of Akt. Stable knockdown of FGFR1 blunted Akt phosphorylation in xenograft tumors. MDA-MB-231 cells co-cultured with CAFs or directly stimulated with FGF2 exhibited enhanced nuclear localization of FGFR1. Notably, FGF2 stimulation produced reactive oxygen species (ROS) accumulation in MDA-MB-231 cells, and FGF2-induced nuclear accumulation of FGFR1 was abrogated by the ROS scavenging agent, N-acetylcysteine.

Improvement of FGF7 Thermal Stability by Introduction of Mutations in Close Vicinity to Disulfide Bond and Surface Salt Bridge

Fibroblast Growth Factor 7 (FGF7), a growth factor specific to epithelial cells, has attracted attention as a therapeutic protein. However, FGF7 has a limitation in its use due to low protein stability. Here, the mutations were designed to increase the stability of FGF7 by analyzing its 3D structure and sequence of other FGFs. Palifermin, N-terminal truncated FGF7 is known to have improved stability and was used as control protein in our study. The K126 and K178 were substituted into glutamate to form salt bridge with the neighboring residue R175 respectively and A120C mutation was introduced in close vicinity to disulfide bond between C133 and C137. The data of Circular Dichroism (CD) showed that all mutant proteins tested had higher Tm value than Palifermin and Tm of A120C/K126E/K178E FGF7 mutant protein was 15.24 °C higher than that of Palifermin. The results of cell proliferation activity and soluble protein analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) after 37 °C or 45 °C incubation exhibited that the stability of A120C mutant protein and A120C-including mutant proteins was improved. These results suggest that the mutation of amino acid in close vicinity to disulfide bond and the salt bridge at the surface of FGF7 enhanced thermal stability and make FGF7 more useful for pharmaceutical and cosmetical application.

The Cross-Talks Among Bone Morphogenetic Protein (BMP) Signaling and Other Prominent Pathways Involved in Neural Differentiation

The bone morphogenetic proteins (BMPs) are a group of potent morphogens which are critical for the patterning, development, and function of the central nervous system. The appropriate function of the BMP pathway depends on its interaction with other signaling pathways involved in neural differentiation, leading to synergistic or antagonistic effects and ultimately favorable biological outcomes. These opposite or cooperative effects are observed when BMP interacts with fibroblast growth factor (FGF), cytokines, Notch, Sonic Hedgehog (Shh), and Wnt pathways to regulate the impact of BMP-induced signaling in neural differentiation. Herein, we review the cross-talk between BMP signaling and the prominent signaling pathways involved in neural differentiation, emphasizing the underlying basic molecular mechanisms regarding the process of neural differentiation. Knowing these cross-talks can help us to develop new approaches in regenerative medicine and stem cell based therapy. Recently, cell therapy has received significant attention as a promising treatment for traumatic or neurodegenerative diseases. Therefore, it is important to know the signaling pathways involved in stem cell differentiation toward neural cells. Our better insight into the cross-talk of signaling pathways during neural development would improve neural differentiation within in vitro tissue engineering approaches and pre-clinical practices and develop futuristic therapeutic strategies for patients with neurological disease.

New Directions and Challenges in Targeted Therapies of Advanced Bladder Cancer: The Role of FGFR Inhibitors

Bladder neoplasms, including the most common urothelial carcinoma, have been an escalating problem for years, especially in highly developed countries. Recent decades have brought us a steadily growing share of this cancer in terms of both morbidity and mortality statistics. Bladder neoplasms are not only a therapeutic challenge but also an economical one due to the demanding, costly diagnostics and treatment. The treatment of urothelial cancer can be divided depending on the stage and advancement; thus, we can distinguish three main categories: non-muscle invasive bladder cancer, conventionally treated by surgical interventions; muscle invasive bladder cancer, conventionally treated with chemotherapeutics; and advanced bladder cancer with distant metastases, conventionally treated with the intensive chemotherapy in the MVAC scheme (methotrexate, vinblastine, doxorubicin, and cisplatin). Recent years have brought a breakthrough: immunotherapy and targeted therapy were discovered to be beneficial for patients disqualified from chemotherapy or patients who progressed despite treatment. This literature review summarizes the latest research into the use of targeted therapy in the treatment of advanced bladder cancer, its benefits, and its limitations.

Comparative genomic analysis of esophageal squamous cell carcinoma and adenocarcinoma: New opportunities towards molecularly targeted therapy

Esophageal cancer is one of the most lethal cancers worldwide because of its rapid progression and poor prognosis. Esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC) are two major subtypes of esophageal cancer. ESCC predominantly affects African and Asian populations, which is closely related to chronic smoking and alcohol consumption. EAC typically arises in Barrett's esophagus with a predilection for Western countries. While surgical operation and chemoradiotherapy have been applied to combat this deadly cancer, molecularly targeted therapy is still at the early stages. With the development of large-scale next-generation sequencing, various genomic alterations in ESCC and EAC have been revealed and their potential roles in the initiation and progression of esophageal cancer have been studied. Potential therapeutic targets have been identified and novel approaches have been developed to combat esophageal cancer. In this review, we comprehensively analyze the genomic alterations in EAC and ESCC and summarize the potential role of the genetic alterations in the development of esophageal cancer. Progresses in the therapeutics based on the different tissue types and molecular signatures have also been reviewed and discussed.

Exploring the effects of genetic variation on gene regulation in cancer in the context of 3D genome structure

Background

Numerous genome-wide association studies (GWAS) conducted to date revealed genetic variants associated with various diseases, including breast and prostate cancers. Despite the availability of these large-scale data, relatively few variants have been functionally characterized, mainly because the majority of single-nucleotide polymorphisms (SNPs) map to the non-coding regions of the human genome. The functional characterization of these non-coding variants and the identification of their target genes remain challenging.

Results

In this communication, we explore the potential functional mechanisms of non-coding SNPs by integrating GWAS with the high-resolution chromosome conformation capture (Hi-C) data for breast and prostate cancers. We show that more genetic variants map to regulatory elements through the 3D genome structure than the 1D linear genome lacking physical chromatin interactions. Importantly, the association of enhancers, transcription factors, and their target genes with breast and prostate cancers tends to be higher when these regulatory elements are mapped to high-risk SNPs through spatial interactions compared to simply using a linear proximity. Finally, we demonstrate that topologically associating domains (TADs) carrying high-risk SNPs also contain gene regulatory elements whose association with cancer is generally higher than those belonging to control TADs containing no high-risk variants.

Conclusions

Our results suggest that many SNPs may contribute to the cancer development by affecting the expression of certain tumor-related genes through long-range chromatin interactions with gene regulatory elements. Integrating large-scale genetic datasets with the 3D genome structure offers an attractive and unique approach to systematically investigate the functional mechanisms of genetic variants in disease risk and progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12863-021-01021-x.

Carotenoids from Marine Sources as a New Approach in Neuroplasticity Enhancement

An increasing number of people experience disorders related to the central nervous system (CNS). Thus, new forms of therapy, which may be helpful in repairing processes' enhancement and restoring declined brain functions, are constantly being sought. One of the most relevant physiological processes occurring in the brain for its entire life is neuroplasticity. It has tremendous significance concerning CNS disorders since neurological recovery mainly depends on restoring its structural and functional organization. The main factors contributing to nerve tissue damage are oxidative stress and inflammation. Hence, marine carotenoids, abundantly occurring in the aquatic environment, being potent antioxidant compounds, may play a pivotal role in nerve cell protection. Furthermore, recent results revealed another valuable characteristic of these compounds in CNS therapy. By inhibiting oxidative stress and neuroinflammation, carotenoids promote synaptogenesis and neurogenesis, consequently presenting neuroprotective activity. Therefore, this paper focuses on the carotenoids obtained from marine sources and their impact on neuroplasticity enhancement.

Roles of fusion genes in digestive system cancers: dawn for cancer precision therapy

For advanced and advanced tumors of the digestive system, personalized, precise treatment could be a lifesaving medicine. With the development of next-generation sequencing technology, detection of fusion genes in solid tumors has become more extensive. Some fusion gene targeting therapies have been written into the guidelines for digestive tract tumors, such as for neurotrophic receptor tyrosine kinase, fibroblast growth factor receptor 2. There are also many fusion genes being investigated as potential future therapeutic targets. This review focuses on the current detection methods for fusion genes, fusion genes written into the digestive system tumor guidelines, and potential fusion gene therapy targets in different organs to discuss the possibility of clinical treatments for these targets in digestive system tumors.

Unmet needs in the treatment of intrahepatic cholangiocarcinoma harboring FGFR2 gene rearrangements

Intrahepatic cholangiocarcinoma, a malignancy of the intrahepatic bile ducts, is the second most common primary liver malignancy and has been rising in incidence over the past several decades. Given its poor prognosis and diagnosis at a late stage, novel therapies are urgently needed to improve outcomes. Intrahepatic cholangiocarcinoma harbors a high rate of targetable mutations, spurring an increased interest in drug development in this disease. FGFR2 gene rearrangements occur in approximately 10-16% of these tumors and this underscores the importance of next generation sequencing in this population. There are now several FGFR inhibitors in development, and these agents may help improve outcomes for these patients. However, both primary and secondary resistance remain a challenge.

Fibroblast Growth Factor 1 Reduces Pulmonary Vein and Atrium Arrhythmogenesis via Modification of Oxidative Stress and Sodium/Calcium Homeostasis

Rationale

Atrial fibrillation is a critical health burden. Targeting calcium (Ca²⁺) dysregulation and oxidative stress are potential upstream therapeutic strategies. Fibroblast growth factor (FGF) 1 can modulate Ca²⁺ homeostasis and has antioxidant activity. The aim of this study was to investigate whether FGF1 has anti-arrhythmic potential through modulating Ca²⁺ homeostasis and antioxidant activity of pulmonary vein (PV) and left atrium (LA) myocytes.

Methods

Patch clamp, western blotting, confocal microscopy, cellular and mitochondrial oxidative stress studies were performed in isolated rabbit PV and LA myocytes treated with or without FGF1 (1 and 10 ng/mL). Conventional microelectrodes were used to record electrical activity in isolated rabbit PV and LA tissue preparations with and without FGF1 (3 μg/kg, i.v.).

Results

FGF1-treated rabbits had a slower heart rate than that observed in controls. PV and LA tissues in FGF1-treated rabbits had slower beating rates and longer action potential duration than those observed in controls. Isoproterenol (1 μM)-treated PV and LA tissues in the FGF1-treated rabbits showed less changes in the increased beating rate and a lower incidence of tachypacing (20 Hz)-induced burst firing than those observed in controls. FGF1 (10 ng/mL)-treated PV and LA myocytes had less oxidative stress and Ca²⁺ transient than those observed in controls. Compared to controls, FGF1 (10 ng/mL) decreased I_Na−L in PV myocytes and lowered I_to, I_Kr−tail in LA myocytes. Protein kinase C (PKC)ε inhibition abolished the effects of FGF1 on the ionic currents of LA and PV myocytes.

Conclusion

FGF1 changes PV and LA electrophysiological characteristics possibly via modulating oxidative stress, Na⁺/Ca²⁺ homeostasis, and the PKCε pathway.

The canonical FGF-FGFR signaling system at the molecular level

Extracellular signaling molecules, among them the fibroblast growth factors (FGFs), enable cells to communicate with neighboring cells. Such signaling molecules that receive and transmit a signal require specific tyrosine kinase receptors located at the cell surface (fibroblast growth factor receptors, FGFRs). The binding of a signaling molecule to its specific receptor results in receptor dimerization and conformational changes in the cytoplasmic part of the receptor. The conformational changes lead to trans-autophosphorylation of the tyrosine kinase domains of the receptors and subsequently to induction of several downstream signaling pathways and expression of appropriate genes. The signaling pathways activated by FGFs control and coordinate cell behaviors such as cell division, migration, differentiation, and cell death. FGFs and their transmembrane receptors are widely distributed in different tissues and participate in fundamental processes during embryonic, fetal, and adult human life. The human FGF/FGFR family comprises 22 ligands and 4 high affinity receptors. In addition, FGFs bind to low affinity receptors, heparan sulfate proteoglycans at the cell surface. The availability of appropriate ligand/receptor pair, combined with the co-receptor, initiates signaling. Inappropriate FGF/FGFR signaling can cause skeletal disorders, primarily dwarfism, craniofacial malformation syndromes, mood disorders, metabolic disorders, and Kallman syndrome. In addition, aberrations in FGF/FGFR signaling have already been reported in several types of malignant diseases. Knowledge about the molecular mechanisms of FGF/FGFR activation and signaling is necessary to understand the basis of these diseases.

Increased Expression and Altered Cellular Localization of Fibroblast Growth Factor Receptor-Like 1 (FGFRL1) Are Associated with Prostate Cancer Progression

Simple Summary

Prostate cancer (PCa) is one of the most frequently diagnosed malignancies in men. PCa is primarily regulated by androgens, but other mechanisms, such as fibroblast growth factor receptor (FGFR) signaling, are also involved. In some patients, PCa relapses after surgical removal of prostate, and androgen deprivation therapy (ADT) is used as the first-line treatment. Unfortunately, the patients often lose response to ADT and progress by other mechanisms to castration-resistant, currently non-curable PCa. In our study, we aimed to identify better diagnostic markers and therapeutic targets against PCa. We analyzed patient PCa tissue samples from radical prostatectomies and biopsies, and used physiologically relevant 3D organoids and mouse xenografts to study FGFR signaling in PCa. We found that FGFRL1, a protein belonging to the FGFR family, plays a role in PCa. Our results suggest that FGFRL1 has significant effects on PCa progression and has potential as a prognostic biomarker.

Abstract

Fibroblast growth factor receptors (FGFRs) 1–4 are involved in prostate cancer (PCa) regulation, but the role of FGFR-like 1 (FGFRL1) in PCa is unclear. FGFRL1 expression was studied by qRT-PCR and immunohistochemistry of patient tissue microarrays (TMAs) and correlated with clinical patient data. The effects of FGFRL1 knockdown (KD) in PC3M were studied in in vitro culture models and in mouse xenograft tumors. Our results showed that FGFRL1 was significantly upregulated in PCa. The level of membranous FGFRL1 was negatively associated with high Gleason scores (GSs) and Ki67, while increased cytoplasmic and nuclear FGFRL1 showed a positive correlation. Cox regression analysis indicated that nuclear FGFRL1 was an independent prognostic marker for biochemical recurrence after radical prostatectomy. Functional studies indicated that FGFRL1-KD in PC3M cells increases FGFR signaling, whereas FGFRL1 overexpression attenuates it, supporting decoy receptor actions of membrane-localized FGFRL1. In accordance with clinical data, FGFRL1-KD markedly suppressed PC3M xenograft growth. Transcriptomics of FGFRL1-KD cells and xenografts revealed major changes in genes regulating differentiation, ECM turnover, and tumor–stromal interactions associated with decreased growth in FGFRL1-KD xenografts. Our results suggest that FGFRL1 upregulation and altered cellular compartmentalization contribute to PCa progression. The nuclear FGFRL1 could serve as a prognostic marker for PCa patients.

Negative regulation of receptor tyrosine kinases by ubiquitination: Key roles of the Cbl family of E3 ubiquitin ligases

Receptor tyrosine kinases (RTKs) serve as transmembrane receptors that participate in a broad spectrum of cellular processes including cellular growth, motility, differentiation, proliferation, and metabolism. Hence, elucidating the regulatory mechanisms of RTKs involved in an assortment of diseases such as cancers attracts increasing interest from researchers. Members of the Cbl family ubiquitin ligases (c-Cbl, Cbl-b and Cbl-c in mammals) have emerged as negative regulators of activated RTKs. Upon activation of RTKs by growth factors, Cbl binds to RTKs via its tyrosine kinase binding (TKB) domain and targets them for ubiquitination, thus facilitating their degradation and negative regulation of RTK signaling. RTKs such as epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGF), fibroblast growth factor receptor (FGFR) and hepatocyte growth factor receptor (HGFR) undergo ubiquitination upon interaction with Cbl family members. In this review, we summarize the current knowledge related to the negative regulation of RTKs by Cbl family proteins.

A monoclonal antibody against basic fibroblast growth factor attenuates cisplatin resistance in lung cancer by suppressing the epithelial-mesenchymal transition

Objectives: To investigate the underlying mechanisms of how the basic fibroblast growth factor monoclonal antibody (bFGFmAb) attenuates cisplatin (DDP) resistance in lung cancer using A549 cells and cisplatin-resistant A549 cells (A549/DDP). Methods: Cancer cell proliferation, cell viability, and 50% inhibitory concentration (IC50) of cisplatin were assessed. Transwell assays were utilized to evaluate the invasion activity of tumor cells in response to treatment. Epithelial-to-mesenchymal transition markers and drug resistance proteins were analysed using Western blots. Results: We demonstrate that the bFGFmAb inhibits the proliferation and invasion of both A549 and A549/DDP cells. The bFGFmAb increases cisplatin sensitivity of both A549 and A549/DDP cells as evidenced by an increase in the IC50 of cisplatin in A549 and A549/DDP cells. Furthermore, bFGFmAb significantly increases the expression of E-cadherin, whilst decreasing the expression of N-cadherin and bFGF in both cell lines, thereby showing inhibition of epithelial-to-mesenchymal transition. In addition, we demonstrate that bFGFmAb significantly reduces the expression of the lung resistance protein. Conclusions: Our data suggests that the humanized bFGFmAb is a promising agent to attenuate cisplatin resistance in NSCLC. The underlying mechanism for this effect of bFGFmAb may be associated with the inhibition of epithelial-to-mesenchymal transition and reduced expression of lung resistance protein.

A validated LC-MS/MS analytical method for the quantification of pemigatinib: metabolic stability evaluation in human liver microsomes

Pemigatinib (PMB) is a small molecule inhibitor of fibroblast growth factor receptor 1 (FGFR1), FGFR2 and FGFR3. On April 17, 2020, the US Food and Drug Administration granted accelerated approval for PMB for the treatment of adults with previously treated, unresectable metastatic or locally advanced cholangiocarcinoma with a fibroblast growth factor receptor 2 (FGFR2) fusion or other rearrangement. PMB is considered the first targeted treatment for cholangiocarcinoma approved in the US. In this study, in silico prediction of PMB metabolic stability was done using the WhichP450 module of the StarDrop software package. Further, an LC-MS/MS analytical method was developed for PMB quantification in human liver microsomes (HLM) to experimentally assess metabolic stability. PMB and flavopiridol (FVL), used as an internal standard IS, were resolved using an isocratic mobile phase and a C18 stationary phase. The LC-MS/MS method showed linearity in the range of 5 to 500 ng mL⁻¹ in an HLM matrix (R² = 0.9995). The lower limit of quantification (LLOQ) was 5 ng mL⁻¹, indicating sensitivity. The inter- and intra-day accuracy and precision were within a variability of 10, confirming the reproducibility of the method. The measured in vitro half-life and intrinsic clearance of PMB were 27.29 min and 25.40 μL min⁻¹ mg⁻¹, respectively. PMB showed a moderate extraction ratio suggesting good bioavailability. The developed analytical method is the first LC-MS/MS method specific for PMB quantification with application to metabolic stability assessment.

PMB showed a moderate extraction ratio suggesting good bioavailability. The developed analytical method is the first LC-MS/MS method specific for PMB quantification with application to metabolic stability assessment.

Therapeutic Targeting of FGFR Signaling in Head and Neck Cancer

ABSTRACT

Squamous cell carcinoma of the head and neck (HNSCC) is the sixth most prevalent cancer worldwide, with an annual incidence of 600,000 new cases. Despite advances in surgery, chemotherapy, and radiotherapy, the overall survival for HNSCC patients has not been significantly improved over the past several decades. Fibroblast growth factor (FGF)/fibroblast growth factor receptor (FGFR) genomic alterations are frequently detected in HNSCC, including amplification, activating mutation, and chromosomal rearrangement. Among them, FGFR1 amplification, FGF amplifications, and FGFR3 mutations are the most prevalent. In addition, FGF/FGFR expression has also been observed in most HNSCCs. However, the prognostic value of FGF/FGFR aberrations remains unclear, especially for gene amplification and overexpression. Nonetheless, FGF/FGFR has been a promising target for HNSCC treatment, and recent preclinical studies demonstrate the potential of the combination treatment regimens involving FGFR inhibitors on HNSCC. Therefore, there are a number of FGFR inhibitors currently in clinical trials for the treatment of head and neck cancers.

Prospective analysis of the expression status of FGFR2 and HER2 in colorectal and gastric cancer populations: DS-Screen Study

PURPOSE

Fibroblast growth factor receptor 2 (FGFR2) and human epidermal growth factor receptor 2 (HER2) proteins are both molecular targets for cancer therapy. The objective of this study was to evaluate the expression status of FGFR2 and HER2 in patients with gastric cancer (GC) or colorectal cancer (CRC).

METHODS

Archived tumor tissue samples from patients with histologically-confirmed GC or CRC suitable for chemotherapy were analyzed for FGFR2 and HER2 expression using immunohistochemistry and fluorescence in situ hybridization (HER2 in CRC only).

RESULTS

A total of 176 GC patients and 389 CRC patients were enrolled. Among patients with GC, 25.6% were FGFR2-positive and 26.1% were HER2-positive. Among patients with CRC, 2.9% were FGFR2-positive and 16.2% were HER2-positive. No clear relationship was found between FGFR2 and HER2 status in either GC or CRC. In GC, FGFR2 and HER2 statuses did not differ between different primary cancer locations, whereas there were some differences between histological types. Based on FGFR2- and/or HER2-positive status, 117 patients were identified as potentially suitable for inclusion in clinical trials of therapeutic agents targeting the relevant protein (GC = 45, CRC = 72; FGFR = 56, HER2 = 62), of whom 7 were eventually enrolled into such clinical trials.

CONCLUSIONS

This study indicated the prevalence of FGFR2 and HER2 in GC and CRC in the Japanese population. The screening performed in this study could be useful for identifying eligible patients for future clinical trials of agents targeting these proteins.

TRIAL REGISTRATION

Clinical trial registration Japic CTI No.: JapicCTI-163380.  https://www.

CLINICALTRIALS

jp/cti-user/trial/ShowDirect.jsp?directLink=RNlzx1PPCuT.PrVNPxPRwA .

Fibroblast Growth Factor 19 Induced Changes in Non-malignant Cholangiocytes

BACKGROUND AND AIMS

Fibroblast growth factor (FGF)19 has been implicated in the pathogenesis of murine hepatocellular carcinoma. Whether it plays a role in the development or course of human cholangiocarcinoma remains to be determined. The aim of this study was to determine whether prolonged exposure to FGF19 results in the transformation of non-malignant human cholangiocytes into cells with malignant features.

METHODS

Human SV-40 transfected non-malignant H69 cholangiocytes were cultured with FGF19 (0-50 ng/mL) for 6 weeks, followed by 6 weeks with medium alone. Cell proliferation, invasion, stem cell surface markers, oncofetoprotein expression, state of differentiation, epithelial-mesenchymal transition (EMT) and interleukin (IL)-6 expression were documented at various time intervals throughout the 12-week period.

RESULTS

FGF19 exposure was associated with significant increases in cell proliferation, de-differentiation, EMT and IL-6 expression. However, each of these effects returned to baseline or control values during the 6-week FGF19 free follow-up period. The remaining cell properties remained unaltered.

CONCLUSIONS

Six weeks of FGF19 exposure did not result in the acquisition of permanent malignant features in non-malignant, human cholangiocytes.

Prospect of lenvatinib for unresectable hepatocellular carcinoma in the new era of systemic chemotherapy

The phase III clinical trial of the novel molecular targeted agent (MTA) lenvatinib for patients with advanced hepatocellular carcinoma (HCC) (REFLECT trial) found that lenvatinib was non-inferior to sorafenib in overall survival. Recently, the efficacy of multiple MTAs, including lenvatinib, in practice has been reported, and therapeutic strategies for Barcelona Clinic Liver Cancer (BCLC) intermediate stage HCC are undergoing major changes. Based on these results, lenvatinib could be recommended for patients with transcatheter arterial chemoembolization (TACE)-refractory, ALBI grade 1, within the up-to-seven criteria in the BCLC intermediate stage. Lenvatinib provides a more favorable outcome than TACE, even in cases with large or multinodular HCC beyond the up-to-seven criteria with Child-Pugh grade A. When patients meet the definitions of TACE-refractory or TACE-unsuitable, switching to systemic chemotherapy, including lenvatinib, is for favorable for preserving liver function. If initial treatment, including MTA, has a significant therapeutic effect and downstaging of HCC is obtained, additional TACE or surgical resection should be considered. Lenvatinib also has a therapeutic effect for poorly differentiated type and non-simple nodular type HCC thanks to the survival-prolonging effect of this drug. Furthermore, a significant therapeutic effect is expected in tumors with more than 50% liver involvement or main portal vein invasion, which have traditionally been considered to have a poor prognosis in patients. This suggests that at the start of lenvatinib treatment, HCC patients with ALBI grade 1 may be able to maintain liver functional reserve.

Paracrine FGFs target skeletal muscle to exert potent anti-hyperglycemic effects

Several members of the FGF family have been identified as potential regulators of glucose homeostasis. We previously reported that a low threshold of FGF-induced FGF receptor 1c (FGFR1c) dimerization and activity is sufficient to evoke a glucose lowering activity. We therefore reasoned that ligand identity may not matter, and that besides paracrine FGF1 and endocrine FGF21, other cognate paracrine FGFs of FGFR1c might possess such activity. Indeed, via a side-by-side testing of multiple cognate FGFs of FGFR1c in diabetic mice we identified the paracrine FGF4 as a potent anti-hyperglycemic FGF. Importantly, we found that like FGF1, the paracrine FGF4 is also more efficacious than endocrine FGF21 in lowering blood glucose. We show that paracrine FGF4 and FGF1 exert their superior glycemic control by targeting skeletal muscle, which expresses copious FGFR1c but lacks β-klotho (KLB), an obligatory FGF21 co-receptor. Mechanistically, both FGF4 and FGF1 upregulate GLUT4 cell surface abundance in skeletal muscle in an AMPKα-dependent but insulin-independent manner. Chronic treatment with rFGF4 improves insulin resistance and suppresses adipose macrophage infiltration and inflammation. Notably, unlike FGF1 (a pan-FGFR ligand), FGF4, which has more restricted FGFR1c binding specificity, has no apparent effect on food intake. The potent anti-hyperglycemic and anti-inflammatory properties of FGF4 testify to its promising potential for use in the treatment of T2D and related metabolic disorders.

Impact of FGF1 on human periodontal ligament fibroblast growth, osteogenic differentiation and inflammatory reaction in vitro

PURPOSE

To investigate in vitro the impact of fibroblast growth factor 1 (FGF1) in comparison to ascorbic acid (AscA) on human periodontal ligament fibroblast (HPdLF) growth, their osteogenic differentiation, and modulation of their inflammatory reaction to mechanical stress.

METHODS

The influence of different concentrations of FGF1 (12.5-200 ng/mL) on growth and proliferation of HPdLF cells was analyzed over 20 days by counting cell numbers and the percentage of Ki67-positive cells. Quantitative expression analysis of genes encoding the osteogenic markers alkaline phosphatase (ALPL), Runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and osteopontin (OSP), as well as the fibroblast markers vimentin (VIM) and fibroblast-specific protein 1 (FSP1), was performed after 2 and 20 days of cultivation. Metabolic activity was determined by MTT assay. For comparison with AscA, 50 ng/mL FGF1 was used for stimulation for 2 and 20 days. Cell number, percentage of Ki67-positive cells, and expression of osteoblast- and fibroblast-specific genes were examined. Alkaline phosphatase activity was visualized by NBT/BCIP and calcium deposits were stained with alizarin red. Cytokine (IL‑6, IL‑8, COX2/PGE2) expression and secretion were analyzed by qPCR and ELISA in 6 h mechanically compressed HPdLF cultured for 2 days with FGF1 or ascorbic acid.

RESULTS

Higher concentrations of FGF1 promoted cell proliferation upon short-term stimulation, whereas prolonged treatment induced the expression of osteogenic markers even with low concentrations. AscA promotes cell growth more markedly than FGF1 in short-term cultures, whereas FGF1 induced osteogenic cell fate more strongly in long-term culture. Both factors induced an increased inflammatory response of HPdLF to mechanical compression.

CONCLUSION

Our data suggest that FGF1 promotes an osteogenic phenotype of HPdLF and limits inflammatory response to mechanical forces compared to AscA.

FGFR signaling and endocrine resistance in breast cancer: Challenges for the clinical development of FGFR inhibitors

Fibroblast growth factors (FGFs) and their receptors (FGFRs) have been extensively investigated in solid malignancies, representing an attractive therapeutic target. In breast cancer, especially in estrogen receptor positive (ER+) subtype, FGFR signaling aberrations have been reported to contribute to proliferation, dedifferentiation, metastasis and drug resistance. However, clinical trials evaluating the use of FGFR inhibitors in breast cancer have had disappointing results. The different biological properties of distinct FGFR alterations and lack of established patient selection criteria, in addition to the early use of non-selective inhibitors, are possible reasons of this failure. Herein, we review the current knowledge regarding the role of FGFR signaling in endocrine resistance in breast cancer. We will also summarize the results from the clinical development of FGFR inhibitors in breast cancer, discussing future challenges to identify the correct cohorts of patients to enroll in trials testing FGFR inhibitors.

Mechanistic Picture for Monomeric Human Fibroblast Growth Factor 1 Stabilization by Heparin Binding

Human fibroblast growth factor (FGF) 1 or hFGF1 is a member of the FGF family that is involved in various vital processes such as cell proliferation, cell differentiation, angiogenesis, and wound healing. hFGF1, which is associated with low stability in vivo, is known to be stabilized by binding heparin sulfate, a glycosaminoglycan that aids the protein in the activation of its cell surface receptor. The poor thermal and proteolytic stability of hFGF1 and the stabilizing role of heparin have long been observed experimentally; however, the mechanistic details of these phenomena are not well understood. Here, we have used microsecond-level equilibrium molecular dynamics (MD) simulations to quantitatively characterize the structural dynamics of monomeric hFGF1 in the presence and absence of heparin hexasaccharide. We have observed a conformational change in the heparin-binding pocket of hFGF1 that occurs only in the absence of heparin. Several intramolecular interactions were also identified within the heparin-binding pocket that form only when hFGF1 interacts with heparin. The loss of both intermolecular and intramolecular interactions in the absence of heparin plausibly leads to the observed conformational change. This conformational transition results in increased flexibility of the heparin-binding pocket and provides an explanation for the susceptibility of apo hFGF1 to proteolytic degradation and thermal instability. This study provides a glimpse into mechanistic details of the heparin-mediated stabilization of hFGF1 and encourages the use of microsecond-level MD in studying the effect of binding on protein structure and dynamics. In addition, the observed differential behavior of hFGF1 in the absence and presence of heparin provides an example, where microsecond-level all-atom MD simulations are necessary to see functionally relevant biomolecular phenomena that otherwise will not be observed on sub-microsecond time scales.

Understanding the Complex Milieu of Epithelial-Mesenchymal Transition in Cancer Metastasis: New Insight Into the Roles of Transcription Factors

Epithelial-mesenchymal transition (EMT) is a physiological program during which polarised, immobile epithelial cells lose connection with their neighbours and are converted to migratory mesenchymal phenotype. Mechanistically, EMT occurs via a series of genetic and cellular events leading to the repression of epithelial-associated markers and upregulation of mesenchymal-associated markers. EMT is very crucial for many biological processes such as embryogenesis and ontogenesis during human development, and again it plays a significant role in wound healing during a programmed replacement of the damaged tissues. However, this process is often hijacked in pathological conditions such as tumour metastasis, which constitutes the most significant drawback in the fight against cancer, accounting for about 90% of cancer-associated mortality globally. Worse still, metastatic tumours are not only challenging to treat with the available conventional radiotherapy and surgical interventions but also resistant to several cytotoxic agents during treatment, owing to their anatomically diffuse localisation in the body system. As the quest to find an effective method of addressing metastasis in cancer intervention heightens, understanding the molecular interplay involving the signalling pathways, downstream effectors, and their interactions with the EMT would be an important requisite while the challenges of metastasis continue to punctuate. Unfortunately, the molecular underpinnings that govern this process remain to be completely illuminated. However, it is becoming increasingly clear that EMT, which initiates every episode of metastasis, significantly requires some master regulators called EMT transcription factors (EMT-TFs). Thus, this review critically examines the roles of TFs as drivers of molecular rewiring that lead to tumour initiation, progression, EMT, metastasis, and colonisation. In addition, it discusses the interaction of various signalling molecules and effector proteins with these factors. It also provides insight into promising therapeutic targets that may inhibit the metastatic process to overcome the limitation of "undruggable" cancer targets in therapeutic design and upturn the current spate of drug resistance. More so, it extends the discussion from the basic understanding of the EMT binary switch model, and ultimately unveiling the E/M cellular plasticity along a phenotypic spectrum via multiple trans-differentiations. It wraps up on how this knowledge update shapes the diagnostic and clinical approaches that may demand a potential shift in investigative paradigm using novel technologies such as single-cell analyses to improve overall patient survival.

From Fragment to Lead: De Novo Design and Development toward a Selective FGFR2 Inhibitor

Fibroblast growth factor receptors (FGFRs) are implicated in a range of cancers with several pan-kinase and selective-FGFR inhibitors currently being evaluated in clinical trials. Pan-FGFR inhibitors often cause toxic side effects and few examples of subtype-selective inhibitors exist. Herein, we describe a structure-guided approach toward the development of a selective FGFR2 inhibitor. De novo design was carried out on an existing fragment series to yield compounds predicted to improve potency against the FGFRs. Subsequent iterative rounds of synthesis and biological evaluation led to an inhibitor with nanomolar potency that exhibited moderate selectivity for FGFR2 over FGFR1/3. Subtle changes to the lead inhibitor resulted in a complete loss of selectivity for FGFR2. X-ray crystallographic studies revealed inhibitor-specific morphological differences in the P-loop which were posited to be fundamental to the selectivity of these compounds. Additional docking studies have predicted an FGFR2-selective H-bond which could be utilized to design more selective FGFR2 inhibitors.

Biological Significance and Targeting of the FGFR Axis in Cancer

The pleiotropic effects of fibroblast growth factors (FGFs), the widespread expression of all seven signalling FGF receptors (FGFRs) throughout the body, and the dramatic phenotypes shown by many FGF/R knockout mice, highlight the diversity, complexity and functional importance of FGFR signalling. The FGF/R axis is critical during normal tissue development, homeostasis and repair. Therefore, it is not surprising that substantial evidence also pinpoints the involvement of aberrant FGFR signalling in disease, including tumourigenesis. FGFR aberrations in cancer include mutations, gene fusions, and amplifications as well as corrupted autocrine/paracrine loops. Indeed, many clinical trials on cancer are focusing on targeting the FGF/FGFR axis, using selective FGFR inhibitors, nonselective FGFR tyrosine kinase inhibitors, ligand traps, and monoclonal antibodies and some have already been approved for the treatment of cancer patients. The heterogeneous tumour microenvironment and complexity of FGFR signalling may be some of the factors responsible for the resistance or poor response to therapy with FGFR axis-directed therapeutic agents. In the present review we will focus on the structure and function of FGF(R)s, their common irregularities in cancer and the therapeutic value of targeting their function in cancer.

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.

Fibroblast growth factor 21 inhibited inflammation and fibrosis after myocardial infarction via EGR1

Myocardial fibrosis in post-myocardial infarction is a self-healing process of the myocardium, making ventricular remodelling difficult to reverse and develop continuously. Fibroblast growth factor 21 (FGF21) plays an essential role in cardiovascular and metabolic diseases. However, the effect and mechanism of FGF21 action on cardiac inflammation and fibrosis caused by myocardial injury have rarely been reported. Adult male Sprague-Dawley rats administered with or without recombinant human basic FGF21 (rhbFGF21) were assessed using echocardiography and haematoxylin-eosin and Masson's trichrome staining to determine the cardiac function and cardiac inflammation and fibrosis levels. FGF21 might improve cardiac remodelling, as characterised by a decrease in the expression of a series of inflammatory and fibrosis-related factors. Moreover, when FGF receptors (FGFRs) were blocked, the effects of FGF21 disappeared. Mechanistically, we found that oxidative stress induced the downregulation of early growth response protein 1 (EGR1), which contributed to inflammatory factors and fibrosis reduction in cardiomyocytes treated with H₂O₂. Collectively, FGF21 effectively suppressed the inflammation and fibrosis in post-infarcted hearts by regulating FGFR-EGR1.

New insights into the role of fibroblast growth factors in Alzheimer's disease

Alzheimer's disease (AD), acknowledged as the most common progressive neurodegenerative disorder, is the leading cause of dementia in the elderly. The characteristic pathologic hallmarks of AD-including the deposition of extracellular senile plaques (SP) formation, intracellular neurofibrillary tangles, and synaptic loss, along with prominent vascular dysfunction and cognitive impairment-have been observed in patients. Fibroblast growth factors (FGFs), originally characterized as angiogenic factors, are a large family of signaling molecules that are implicated in a wide range of biological functions in brain development, maintenance and repair, as well as in the pathogenesis of brain-related disorders including AD. Many studies have focused on the implication of FGFs in AD pathophysiology. In this review, we will provide a summary of recent findings regarding the role of FGFs and their receptors in the pathogenesis of AD, and discuss the possible opportunities for targeting these molecules as novel treatment strategies in AD.

Fibroblast growth factor receptor fusions in cancer: opportunities and challenges

Fibroblast growth factors (FGFs) and their receptors (FGFRs) play critical roles in many biological processes and developmental functions. Chromosomal translocation of FGFRs result in the formation of chimeric FGFR fusion proteins, which often cause aberrant signaling leading to the development and progression of human cancer. Due to the high recurrence rate and carcinogenicity, oncogenic FGFR gene fusions have been identified as promising therapeutic targets. Erdafitinib and pemigatinib, two FGFR selective inhibitors targeting FGFR fusions, have been approved by the U.S. Food and Drug Administration (FDA) to treat patients with urothelial cancer and cholangiocarcinoma, respectively. Futibatinib, a third-generation FGFR inhibitor, is under phase III clinical trials in patients with FGFR gene rearrangements. Herein, we review the current understanding of the FGF/FGFRs system and the oncogenic effect of FGFR fusions, summarize promising inhibitors under clinical development for patients with FGFR fusions, and highlight the challenges in this field.

[Pharmacological characteristics and clinical study results of Pemigatinib (Pemazyre® Tablets), a selective fibroblast growth factor receptor (FGFR) inhibitor]

Pemigatinib (Pemazyre^® Tablets 4.5 mg) is a novel fibroblast growth factor receptor (FGFR) inhibitor, created by Incyte Corporation. The product was approved in March 2021 and was launched in June 2021 for the treatment of patients with locally advanced or metastatic biliary tract cancer (BTC) with a fibroblast growth factor receptor 2 (FGFR2) fusion or rearrangement that has progressed after at least one prior line of systemic therapy. Pemigatinib was shown to selectively inhibit kinase activity of FGFR1～3 (IC₅₀; 0.39～1.2 nM). In cultured cells, pemigatinib inhibited the phosphorylation of FGFR1 and its downstream signals, ERK1/2 and STAT5 in a concentration-dependent manner. Pemigatinib also potently inhibited the growth of various types of cell lines with FGFR 1～3 gene alteration. Pemigatinib was shown to induce concentration-dependent tumor regression in a tumor xenograft model mice in which tumor tissue sections from patients with cholangiocarcinoma (CCA) harboring FGFR2 gene fusions were transplanted. Pemigatinib was well tolerated in Japanese and overseas Phase1 studies (INCB 54828-101 and 202). In the global phase2 study (INCB 54828-202) conducted in CCA patients with FGFR2 gene fusions or rearrangements, significant improvement in the overall response rate was observed. Although several adverse reactions were observed which was based on the mechanism of action of pemigatinib, the safety profile and management of the adverse reactions were favorable. Pemigatinib is expected to contribute to second-line drug treatment after failure of standard therapies in biliary tract cancer.

Lenvatinib: established and promising drug for the treatment of advanced hepatocellular carcinoma

INTRODUCTION

: The evolving therapeutic landscape of advanced hepatocellular carcinoma (HCC) includes the increasing implementation of target-therapy and immunotherapy. Lenvatinib, a multi-target tyrosine kinase inhibitor (TKI), is an emerging first-line therapy for hepatocellular carcinoma. Its approval has changed the scenario of first-line therapies for advanced HCC, where just sorafenib proved clinical efficacy for over a decade.

AREAS COVERED

: The current evidence on the role of lenvatinib for patients with advanced HCC is reviewed in this article. Particularly, therapeutic mechanisms and clinical efficacy of lenvatinib are summarized and the management of adverse events is discussed. In addition, future perspectives on the emerging role of combine therapy for HCC are highlighted.

EXPERT OPINION

In the first line, lenvatinib was found to be non-inferior to sorafenib for overall survival, with significantly better progression-free survival and objective response rate. Immune checkpoint inhibitors (ICIs) are now part of HCC treatment, and recently the combination of atezolizumab plus bevacizumab has become the recommended standard of care first-line therapy for selected patients. The antitumor and immunomodulatory activities that lenvatinib shows in preclinical studies, and the positive outcomes achieved using a combination of lenvatinib plus ICIs, open new perspectives for advanced HCC treatment.

Trophic factors as potential therapies for treatment of major mental disorders

Notwithstanding major advances in psychotherapeutics, their efficacy and specificity remain limited. The slow onset of beneficial outcomes and numerous adverse effects of widely used medications remain of chief concern, warranting in-depth studies. The majority of frontline therapies are thought to enhance the endogenous monoaminergic drive, to initiate a cascade of molecular events leading to lasting functional and structural plasticity. They also involve alterations in trophic factor signalling, including brain-derived neurotrophic factor (BDNF), VGF (non-acronymic), vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), glial cell-derived neurotrophic factor (GDNF), and others. In several major mental disorders, emerging data suggest protective and restorative effects of trophic factors in preclinical models, when applied on their own. Antidepressant outcomes of VGF and FGF2, for instance, were shown in experimental animals, while BDNF and GDNF prove useful in the treatment of addiction, schizophrenia, and autism spectrum disorders. The main challenge with the effective translation of these and other findings in the clinic is the knowledge gap in action mechanisms with potential risks, as well as the lack of effective platforms for validation under clinical settings. Herein, we review the state-of-the-art and advances in the therapeutic use of trophic factors in several major neuropsychiatric disorders.

Roles of Therapeutic Bioactive Compounds in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is due to poor prognosis and lack of availability of effective treatment. Novel therapeutic strategies will be the fine tuning of intracellular ROS signaling to effectively deprive cells of ROS-induced tumor-promoting events. This review discusses the generation of ROS, the major signaling their modulation in therapeutics. We explore some of the major pathways involved in HCC, which include the VEGF, MAPK/ERK, mTOR, FGF, and Ser/Thr kinase pathways. In this review, we study cornerstone on natural bioactive compounds with their effect on hepatocarcinomas. Furthermore, we focus on oxidative stress and FDA-approved signaling pathway inhibitors, along with chemotherapy and radiotherapy enhancers which with early evidence of success. While more in vivo testing is required to confirm the findings presented here, our findings will aid future nonclinical, preclinical, and clinical studies with these compounds, as well as inspire medicinal chemistry scientists to conduct appropriate research on this promising natural compound and their derivatives.

Targeted Therapy for Advanced or Metastatic Cholangiocarcinoma: Focus on the Clinical Potential of Infigratinib

Cholangiocarcinoma is one of the most aggressive cancers, with a 5-year survival rate of 11-44% after surgical resection. However, there is no established systemic therapy after failure of the gemcitabine plus cisplatin first-line therapy with exception of FOLFOX. Fibroblast growth factor receptor (FGFR) genomic aberrations have been detected in cholangiocarcinoma, and targeting these genomic aberrations with FGFR inhibitors has shown remarkable clinical benefits in advanced cholangiocarcinoma. In this article, we provide up-to-date information on the clinical development of selective FGFR inhibitors in advanced cholangiocarcinoma, focusing on infigratinib. In a Phase 1 trial, infigratinib showed a safe profile. In a following Phase 2 trial, infigratinib showed remarkable efficacy in advanced cholangiocarcinoma with FGFR2 fusions or rearrangements, and the Food and Drug Administration (FDA) approved infigratinib for cholangiocarcinoma in May 2021 largely based on tumor response and duration of response. Currently infigratinib is on a Phase 3 trial (PROOF301) as a first-line setting compared to the GEMCIS therapy in advanced cholangiocarcinoma. Given that the FGFR genomic aberrations including FGFR2 fusions are rarely accompanied with other targetable mutations, infigratinib and other FGFR inhibitors are continuously expected to be the novel targeted agents in cholangiocarcinoma harboring these aberrations. Acquired resistance to infigratinib was reported in several recent studies which could potentially be a barrier to overcome. Active clinical trials including PROOF301 are expected to elucidate the clinical benefits of infigratinib in this disease. Infigratinib combined with immunotherapy is also a potential future direction of investigation in cholangiocarcinoma.

The Multiple Roles of Fibroblast Growth Factor in Diabetic Nephropathy

Diabetic nephropathy (DN) is a common microvascular complication in the late stages of diabetes. Currently, the etiology and pathogenesis of DN are not well understood. Even so, available evidence shows its development is associated with metabolism, oxidative stress, cytokine interaction, genetic factors, and renal microvascular disease. Diabetic nephropathy can lead to proteinuria, edema and hypertension, among other complications. In severe cases, it can cause life-threatening complications such as renal failure. Patients with type 1 diabetes, hypertension, high protein intake, and smokers have a higher risk of developing DN. Fibroblast growth factor (FGF) regulates several human processes essential for normal development. Even though FGF has been implicated in the pathological development of DN, the underlying mechanisms are not well understood. This review summarizes the role of FGF in the development of DN. Moreover, the association of FGF with metabolism, inflammation, oxidative stress and fibrosis in the context of DN is discussed. Findings of this review are expected to deepen our understanding of DN and generate ideas for developing effective prevention and treatments for the disease.

A rare case of atypical chronic myeloid leukemia associated with t(8;22)(p11.2;q11.2)/ BCR-FGFR1 rearrangement: A case report and literature review

Myeloid/lymphoid neoplasm with t(8;22)(p11.2;q11.2)/BCR-FGFR1 is an extremely rare diagnosis, with few reported cases to date. In contrast to other FGFR1-partner rearrangements that are associated with chronic eosinophilic leukemia, acute myeloid leukemia, and/or lymphoblastic lymphoma, patients with BCR-FGFR1 have a myeloproliferative disorder that closely resembles chronic myeloid leukemia (CML). The current report describes a rare case of a 61 year old man with an atypical CML phenotype associated with t(8;22)(p11.2;q11.2)/BCR-FGFR1. A literature review is presented to enhance the awareness of this rare diagnostic entity.

New FDA oncology small molecule drugs approvals in 2020: Mechanism of action and clinical applications

In 2020, fifty-three new drugs, including forty small-molecules (thirty-six new chemical entities and four new diagnostic agents) and thirteen biologic drugs were approved by the U.S. Food and Drug Administration (FDA). This year, small-molecules continue to play a role in innovative treatments representing around 75% of all drugs accepted by FDA. The dominant therapeutic area was oncology, accounting for twenty-three new approvals, including thirteen new chemical entities, four new diagnostic agents, and thirteen biologic drugs. Recognizing the importance of small-molecules on cancer treatment, this review aims to provide an overview regarding the clinical applications and mechanism of action of the thirteen new small-molecules (excluding new diagnostic agents) approved by FDA in 2020.

Expression of p53 Protein Associates with Anti-PD-L1 Treatment Response on Human-Derived Xenograft Model of GATA3/CR5/6-Negative Recurrent Nonmuscular Invasive Bladder Urothelial Carcinoma

BACKGROUND

The possible involvement of p53 signaling, FGFR3 expression, and FGFR3 mutation rates in the prediction of the NMIBC anti-PD-L1 treatment response needs to be clarified. The main aim of our study was to explore predictive value of p53 expression, FGFR3 expression, and its gene mutation status for the therapeutic success of anti-PD-L1 treatment in the patient-derived murine model of recurrent high-PD-L1(+) GATA3(-)/CR5/6(-) high-grade and low-grade NMIBC.

METHODS

twenty lines of patient-derived xenografts (PDXs) of relapsed high-PD-L1(+) double-negative NMIBC were developed, of which 10 lines represented high-grade tumors and the other ones-low-grade bladder cancer. Acceptors of each grade-related branch received specific anti-PD-L1 antibodies. Animals' survival, tumor-doubling time, and remote metastasis were followed during the post-interventional period. PD-L1, GATA3, CR5/6, and p53 protein expressions in engrafted tumors were assessed by immunohistochemistry. The FGFR3 expression and FGFR3 mutations in codons 248 and 249 were detected by real-time polymerase chain reaction.

RESULTS

The expression of p53 protein is an independent factor affecting the animals' survival time [HR = 0.036, p = 0.031] of anti-PD-L1-treated mice with low-grade high-PD-L1(+) double-negative NMIBC PDX. The FGFR3 expression and FGFR3 mutation rate have no impact on the anti-PD-L1 treatment response in the interventional groups.

CONCLUSIONS

p53 expression may be considered as a prognostic factor for the anti-PD-L1 treatment efficacy of low-grade high-PD-L1-positive GATA3(-)/CR5/6(-)-relapsed noninvasive bladder cancer.

Angiogenesis induction in breast cancer: A paracrine paradigm

Breast cancer is the most prevalent type of cancer among women globally. Angiogenesis contributes significantly to breast cancer progression and dissemination. Neovascularization is concurrent with the progression and growth of breast cancer. Breast cancer cells control angiogenesis by secreting pro-angiogenic factors like fibroblast growth factor, vascular endothelial growth factor, interleukin, transforming growth factor-β, platelet-derived growth factor and several others. These pro-angiogenic factors trigger neovascularization, and thereby lead to breast cancer development and metastasis. The hypoxia-inducible factor (HIF)-regulated angiogenesis cascade is a crucial underlying factor in breast cancer growth and metastasis. To that end, several efforts have been made to identify druggable targets within the HIF-angiogenesis components. However, escape pathways are a major hindrance for targeted therapies against angiogenesis. Thus, understanding the key factors that trigger breast cancer angiogenesis is critical in elucidating ways to inhibit breast cancer. The current review provides an overview of the key growth factors that trigger breast cancer angiogenesis.

FGF9/FGFR1 promotes cell proliferation, epithelial-mesenchymal transition, M2 macrophage infiltration and liver metastasis of lung cancer

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FGF9 induced cell proliferation, EMT, migration, and invasion of mouse Lewis lung cancer (LLC) cells, in vitro.

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FGF9 interacted with FGFR1 and activated FAK, AKT, and ERK/MAPK signal pathways, induced the expression of EMT key proteins (N-cadherin, vimentin, snail, MMP2, MMP3 and MMP13) and reduced the expression of E-cadherin.

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FGF9 promoted liver metastasis of subcutaneous inoculated LLC tumor with tumor growth, angiogenesis, EMT and M2-macrophage infiltration in the tumor microenvironment.

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The FGF9/LLC syngeneic animal model provides a useful tool for the mechanism studies of liver metastasis which is the worst prognostic factor for lung cancer patients with distant organ metastasis.

Fibroblast growth factors 9 (FGF9) modulates cell proliferation, differentiation and motility for development and repair in normal cells. Abnormal activation of FGF9 signaling is associated with tumor progression in many cancers. Also, FGF9 may be an unfavorable prognostic indicator for non-small cell lung cancer patients. However, the effects and mechanisms of FGF9 in lung cancer remain elusive. In this study, we investigated the FGF9-induced effects and signal activation profiles in mouse Lewis lung carcinoma (LLC) in vitro and in vivo. Our results demonstrated that FGF9 significantly induced cell proliferation and epithelial-to-mesenchymal transition (EMT) phenomena (migration and invasion) in LLC cells. Mechanism-wise, FGF9 interacted with FGFR1 and activated FAK, AKT, and ERK/MAPK signal pathways, induced the expression of EMT key proteins (N-cadherin, vimentin, snail, MMP2, MMP3 and MMP13), and reduced the expression of E-cadherin. Moreover, in the allograft mouse model, intratumor injection of FGF9 to LLC-tumor bearing C57BL/6 mice enhanced LLC tumor growth which were the results of increased Ki67 expression and decreased cleaved caspase-3 expression compared to control groups. Furthermore, we have a novel finding that FGF9 promoted liver metastasis of subcutaneous inoculated LLC tumor with angiogenesis, EMT and M2-macrophage infiltration in the tumor microenvironment. In conclusion, FGF9 activated FAK, AKT, and ERK signaling through FGFR1 with induction of EMT to stimulate LLC tumorigenesis and hepatic metastasis. This novel FGF9/LLC allograft animal model may therefore be useful to study the mechanism of liver metastasis which is the worst prognostic factor for lung cancer patients with distant organ metastasis.

Chronic exposure to FGF2 converts iPSCs into cancer stem cells with an enhanced integrin/focal adhesion/PI3K/AKT axis

We previously demonstrated the conversion of normal stem cells, including induced pluripotent stem cells (iPSCs), into cancer stem cells (CSCs) without genetic manipulation. Herein, we designed a meta-analysis to assess gene expression profiles in different breast cancer cell lines focusing on the secretory factors responsible for conversion. As a result, fibroblast growth factor 2 (FGF2) was found to be the best candidate in T47D and BT549 cells, of which conditioned medium was previously successful in inducing CSCs. When treated with 3.1 μg/ml FGF2, mouse iPSCs not only maintained survival without LIF for three weeks but also acquired growth ability independent of FGF2. The resultant cells exhibited expression of stemness and cancer stem cell markers, sphere-forming ability, differentiation, and tumorigenicity with malignancy. The primary cultures of the tumor confirmed the signatures of CSCs with two different phenotypes with or without GFP expression under control of the Nanog promoter. Bioinformatic analysis of gene expression profiles suggested constitutive autocrine activation of the FGF receptor, integrins, focal adhesions, and PI3K/AKT pathways. FGF2 could potently initiate cancer as a component of the inflammatory microenvironment.

Functional Roles of FGF Signaling in Early Development of Vertebrate Embryos

Fibroblast growth factors (FGFs) comprise a large family of growth factors, regulating diverse biological processes including cell proliferation, migration, and differentiation. Each FGF binds to a set of FGF receptors to initiate certain intracellular signaling molecules. Accumulated evidence suggests that in early development and adult state of vertebrates, FGFs also play exclusive and context dependent roles. Although FGFs have been the focus of research for therapeutic approaches in cancer, cardiovascular disease, and metabolic syndrome, in this review, we mainly focused on their role in germ layer specification and axis patterning during early vertebrate embryogenesis. We discussed the functional roles of FGFs and their interacting partners as part of the gene regulatory network for germ layer specification, dorsal-ventral (DV), and anterior-posterior (AP) patterning. Finally, we briefly reviewed the regulatory molecules and pharmacological agents discovered that may allow modulation of FGF signaling in research.

Nuclear FGFR1 Regulates Gene Transcription and Promotes Antiestrogen Resistance in ER+ Breast Cancer

PURPOSE

FGFR1 overexpression has been associated with endocrine resistance in ER⁺ breast cancer. We found FGFR1 localized in the nucleus of breast cancer cells in primary tumors resistant to estrogen suppression. We investigated a role of nuclear FGFR1 on gene transcription and antiestrogen resistance.

EXPERIMENTAL DESIGN

Tumors from patients treated with letrozole were subjected to Ki67 and FGFR1 IHC. MCF7 cells were transduced with FGFR1(SP-)(NLS) to promote nuclear FGFR1 overexpression. FGFR1 genomic activity in ER⁺/FGFR1-amplified breast cancer cells ± FOXA1 siRNA or ± the FGFR tyrosine kinase inhibitor (TKI) erdafitinib was examined by chromatin immunoprecipitation sequencing (ChIP-seq) and RNA sequencing (RNA-seq). The nuclear and chromatin-bound FGFR1 interactome was investigated by mass spectrometry (MS).

RESULTS

High nuclear FGFR1 expression in ER⁺ primary tumors positively correlated with post-letrozole Ki67 values. Nuclear FGFR1 overexpression influenced gene transcription and promoted resistance to estrogen suppression and to fulvestrant in vivo. A gene expression signature induced by nuclear FGFR1 correlated with shorter survival in the METABRIC cohort of patients treated with antiestrogens. ChIP-Seq revealed FGFR1 occupancy at transcription start sites, overlapping with active transcription histone marks. MS analysis of the nuclear FGFR1 interactome identified phosphorylated RNA-Polymerase II and FOXA1, with FOXA1 RNAi impairing FGFR1 recruitment to chromatin. Treatment with erdafitinib did not impair nuclear FGFR1 translocation and genomic activity.

CONCLUSIONS

These data suggest nuclear FGFR1 contributes to endocrine resistance by modulating gene transcription in ER⁺ breast cancer. Nuclear FGFR1 activity was unaffected by FGFR TKIs, thus supporting the development of treatment strategies to inhibit nuclear FGFR1 in ER+/FGFR1 overexpressing breast cancer.

Fibroblast Growth Factor Signalling in the Diseased Nervous System

Fibroblast growth factors (FGFs) act as key signalling molecules in brain development, maintenance, and repair. They influence the intricate relationship between myelinating cells and axons as well as the association of astrocytic and microglial processes with neuronal perikarya and synapses. Advances in molecular genetics and imaging techniques have allowed novel insights into FGF signalling in recent years. Conditional mouse mutants have revealed the functional significance of neuronal and glial FGF receptors, not only in tissue protection, axon regeneration, and glial proliferation but also in instant behavioural changes. This review provides a summary of recent findings regarding the role of FGFs and their receptors in the nervous system and in the pathogenesis of major neurological and psychiatric disorders.

Antitumor effects of 3-bromoascochlorin on small cell lung cancer via inhibiting MAPK pathway

Small cell lung cancer (SCLC) was defined as a recalcitrant cancer, and novel therapies are urgently needed. Marine natural products (MNPs) may bring continuing hope for treatment of SCLC. In this study, 3-bromoascochlorin (BAS), an MNP isolated from the coral-derived fungus Acremonium sclerotigenum GXIMD 02501, was primarily screened out with antiproliferative activity towards SCLC cell lines. Then western blot analysis (WB) and flow cytometry were conducted, and we found BAS could induce the apoptosis of H446 and H69AR cells. Besides, BAS could suppress the invasion and migration of H446. In an SCLC xenograft mice model, BAS inhibited the growth of tumor without affecting the body weight of mice. Finally, the underlying mechanisms were preliminarily explored. According to the results of RNA-seq, reverse transcription-quantitative polymerase chain reaction, and WB, our results revealed that BAS exerted antitumor activity via inhibiting mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinases (ERK) pathway. Collectively, these results indicated that BAS can be used as a promising compound for the treatment of human SCLC.