Fibroblast growth factors (FGFs) in cancer: FGF traps as a new therapeutic approach

Antitumor effect of memantine is related to the formation of the splicing isoform of GLG1, a decoy FGF‑binding protein

Drug repositioning is a strategy for repurposing the approved or investigational drugs that are outside the scope of the original medical indication. Memantine is used as a non‑competitive N‑methyl‑D‑aspartate receptor antagonist to prevent glutamate‑mediated excitotoxicity in Alzheimer's disease, and is one of the promising agents which is utilized for the purpose of cancer therapy. However, the association between memantine and Golgi glycoprotein 1 (GLG1), an intracellular fibroblast growth factor receptor, in cancers has not yet been clarified. The present study analyzed the expression and location of GLG1 in tumor cells treated with memantine. Memantine was found to suppress the growth of malignant glioma and breast cancer cells in a concentration‑dependent manner. The mRNA expression of GLG1 was upregulated in a concentration‑dependent manner, and the splicing variant profiles were altered in all cell lines examined. The results of western blot analysis revealed an increase in the full‑length and truncated forms of GLG1. Moreover, GLG1 spread in the cytosol of memantine‑treated cells, whereas it localized in the Golgi apparatus in control cells. Since GLG1 functions as a decoy FGF receptor, the modulation of GLG1 may prove to be one of the mechanisms underlying the cancer‑suppressive effects of memantine.

Changing Landscape of Systemic Therapy in Biliary Tract Cancer

Biliary tract cancers (BTC) are often diagnosed at advanced stages and have a grave outcome due to limited systemic options. Gemcitabine and cisplatin combination (GC) has been the first-line standard for more than a decade. Second-line chemotherapy (CT) options are limited. Targeted therapy or TT (fibroblast growth factor 2 inhibitors or FGFR2, isocitrate dehydrogenase 1 or IDH-1, and neurotrophic tyrosine receptor kinase or NTRK gene fusions inhibitors) have had reasonable success, but <5% of total BTC patients are eligible for them. The use of immune checkpoint inhibitors (ICI) such as pembrolizumab is restricted to microsatellite instability high (MSI-H) patients in the first line. The success of the TOPAZ-1 trial (GC plus durvalumab) is promising, with numerous trials underway that might soon bring targeted therapy (pemigatinib and infrigatinib) and ICI combinations (with CT or TT in microsatellite stable cancers) in the first line. Newer targets and newer agents for established targets are being investigated, and this may change the BTC management landscape in the coming years from traditional CT to individualized therapy (TT) or ICI-centered combinations. The latter group may occupy major space in BTC management due to the paucity of targetable mutations and a greater toxicity profile.

Advanced Bile Duct Cancers: A Focused Review on Current and Emerging Systemic Treatments

Cancers arising in the biliary tract are rare, with varied incidence depending on geographical location. As clinical presentation is typically vague with non-specific symptoms, a large proportion of patients present with unresectable or metastatic disease at diagnosis. When unresectable, the mainstay of treatment is cytotoxic chemotherapy; however, despite this, 5-year overall survival remains incredibly poor. Diagnostic molecular pathology, using next-generation sequencing, has identified a high prevalence of targetable alterations in bile duct cancers, which is transforming care. Substantial genomic heterogeneity has been identified depending on both the anatomical location and etiology of disease, with certain alterations enriched for subtypes. In addition, immune checkpoint inhibitors with anti-PD-1/PD-L1 antibodies in combination with chemotherapy are now poised to become the standard first-line treatment option in this disease. Here, we describe the established role of cytotoxic chemotherapy, targeted precision treatments and immunotherapy in what is a rapidly evolving treatment paradigm for advanced biliary tract cancer.

Natural latex serum: characterization and biocompatibility assessment using Galleria mellonella as an alternative in vivo model

Natural latex serum (NLS) is one of the natural rubber latex fractions from Hevea brasiliensis tree, which is formed by centrifuged serum and is composed of proteins, acids, nucleotides, salts and carbohydrates. The proteins present in NLS have demonstrated several interesting biological properties, including angiogenic, healing, osteogenic, anti-inflammatory, antimicrobial, in addition to inducing neovascularization, bone formation and osseointegration. Thus, we proposed to characterize NLS by physicochemical techniques and to investigate the biocompatibility by toxicological assays and safety test in Galleria mellonella. Infrared spectrum showed vibrational bands characteristic of amide I, II and III that are linked to the protein content, which was confirmed by the High Performance Liquid Chromatography profile and by the Electrophoresis analysis. This material did not exhibit hemolytic (rate <0.5%) and cytotoxic effects (viability >70%) and was able to enhance the proliferation of fibroblasts (>600%) after 3 days. The pronounced proliferative effect observed in fibroblast cells can be explained by the presence of the fibroblast growth factor (FGF) like protein revealed by the Western blot test. Moreover, NLS did not provoke toxic effects (survival ∼ 80%) on the G. mellonella model, indicating that it is a biocompatible and safe material.

Targeted Therapies for Perihilar Cholangiocarcinoma

Perihilar cholangiocarcinoma (pCCA) is the anatomical sub-group of biliary tract cancer (BTC) arising between the second-order intrahepatic bile ducts and the cystic duct. Together with distal and intrahepatic cholangiocarcinoma (dCCA and iCCA; originating distal to, and proximal to this, respectively), gallbladder cancer (GBC) and ampulla of Vater carcinoma (AVC), these clinicopathologically and molecularly distinct entities comprise biliary tract cancer (BTC). Most pCCAs are unresectable at diagnosis, and for those with resectable disease, surgery is extensive, and recurrence is common. Therefore, the majority of patients with pCCA will require systemic treatment for advanced disease. The prognosis with cytotoxic chemotherapy remains poor, driving interest in therapies targeted to the molecular nature of a given patient's cancer. In recent years, the search for efficacious targeted therapies has been fuelled both by whole-genome and epigenomic studies, looking to uncover the molecular landscape of CCA, and by specifically testing for aberrations where established therapies exist in other indications. This review aims to provide a focus on the current molecular characterisation of pCCA, targeted therapies applicable to pCCA, and future directions in applying personalised medicine to this difficult-to-treat malignancy.

Exploring the FGF/FGFR System in Ocular Tumors: New Insights and Perspectives

Ocular tumors are a family of rare neoplasms that develop in the eye. Depending on the type of cancer, they mainly originate from cells localized within the retina, the uvea, or the vitreous. Even though current treatments (e.g., radiotherapy, transpupillary thermotherapy, cryotherapy, chemotherapy, local resection, or enucleation) achieve the control of the local tumor in the majority of treated cases, a significant percentage of patients develop metastatic disease. In recent years, new targeting therapies and immuno-therapeutic approaches have been evaluated. Nevertheless, the search for novel targets and players is eagerly required to prevent and control tumor growth and metastasis dissemination. The fibroblast growth factor (FGF)/FGF receptor (FGFR) system consists of a family of proteins involved in a variety of physiological and pathological processes, including cancer. Indeed, tumor and stroma activation of the FGF/FGFR system plays a relevant role in tumor growth, invasion, and resistance, as well as in angiogenesis and dissemination. To date, scattered pieces of literature report that FGFs and FGFRs are expressed by a significant subset of primary eye cancers, where they play relevant and pleiotropic roles. In this review, we provide an up-to-date description of the relevant roles played by the FGF/FGFR system in ocular tumors and speculate on its possible prognostic and therapeutic exploitation.

Fibroblast growth factor receptor signalling dysregulation and targeting in breast cancer

Fibroblast Growth Factor Receptor (FGFR) signalling plays a critical role in breast embryonal development, tissue homeostasis, tumorigenesis and metastasis. FGFR, its numerous FGF ligands and signalling partners are often dysregulated in breast cancer progression and are one of the causes of resistance to treatment in breast cancer. Furthermore, FGFR signalling on epithelial cells is affected by signals from the breast microenvironment, therefore increasing the possibility of breast developmental abnormalities or cancer progression. Increasing our understanding of the multi-layered roles of the complex family of FGFRs, their ligands FGFs and their regulatory partners may offer novel treatment strategies for breast cancer patients, as a single agent or rational co-target, which will be explored in depth in this review.

FGFR blockade by pemigatinib treats naïve and castration resistant prostate cancer

Prostate cancer (PCa) is a leading cause of cancer mortality in the male population commonly treated with androgen deprivation therapy (ADT) and relapsing as aggressive and androgen-independent castration-resistant prostate cancer (CRPC). In PCa the FGF/FGFR family of growth factors and receptors represents a relevant mediator of cancer growth, tumor-stroma interaction, and a driver of resistance and relapse to ADT. In the present work, we validate the therapeutic efficacy the FDA-approved FGFR inhibitor pemigatinib, in an integrated platform consisting of human and murine PCa cells, and the transgenic multistage TRAMP model of PCa that recapitulates both androgen-dependent and CRPC settings. Our results show for the first time that pemigatinib causes intracellular stress and cell death in PCa cells and prevents tumor growth in vivo and in the multistage model. In addition, the combination of pemigatinib with enzalutamide resulted in long-lasting tumor inhibition and prevention of CRPC relapse in TRAMP mice. These data are confirmed by the implementation of a stochastic mathematical model and in silico simulation. Pemigatinib represents a promising FDA-approved FGFR inhibitor for the treatment of PCa and CRPC alone and in combination with enzalutamide.

Dark and bright side of targeting fibroblast growth factor receptor 4 in the liver

Fibroblast growth factor (FGF) receptor 4 (FGFR4) and its cognate ligand, FGF19, are implicated in a range of cellular processes, including differentiation, metabolism and proliferation. Indeed, their aberrant activation has been associated with the development of hepatic tumours. Despite great advances in early diagnosis and the development of new therapies, liver cancer is still associated with a high mortality rate, owing primarily to high molecular heterogeneity and unclear molecular targeting. The development of FGFR4 inhibitors is a promising tool in patients with concomitant supraphysiological levels of FGF19 and several clinical trials are testing these treatments for patients with advanced hepatocellular carcinoma (HCC). Conversely, using FGF19 analogues to activate FGFR4-KLOTHO β represents a novel therapeutic strategy in patients presenting with cholestatic liver disorders and non-alcoholic steatohepatitis, which could potentially prevent the development of metabolic HCC. Herein, we provide an overview of the currently available therapeutic options for targeting FGFR4 in HCC and other liver diseases, highlighting the need to carefully stratify patients and personalise therapeutic strategies.

The Role of Fibroblast Growth Factor (FGF) Signaling in Tissue Repair and Regeneration

Fibroblast growth factors (FGFs) are a large family of secretory molecules that act through tyrosine kinase receptors known as FGF receptors. They play crucial roles in a wide variety of cellular functions, including cell proliferation, survival, metabolism, morphogenesis, and differentiation, as well as in tissue repair and regeneration. The signaling pathways regulated by FGFs include RAS/mitogen-activated protein kinase (MAPK), phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)–protein kinase B (AKT), phospholipase C gamma (PLCγ), and signal transducer and activator of transcription (STAT). To date, 22 FGFs have been discovered, involved in different functions in the body. Several FGFs directly or indirectly interfere with repair during tissue regeneration, in addition to their critical functions in the maintenance of pluripotency and dedifferentiation of stem cells. In this review, we summarize the roles of FGFs in diverse cellular processes and shed light on the importance of FGF signaling in mechanisms of tissue repair and regeneration.

FGF/FGFR-Dependent Molecular Mechanisms Underlying Anti-Cancer Drug Resistance

Simple Summary

Deregulation of the FGF/FGFR axis is associated with many types of cancer and contributes to the development of chemoresistance, limiting the effectiveness of current treatment strategies. There are several mechanisms involved in this phenomenon, including cross-talks with other signaling pathways, avoidance of apoptosis, stimulation of angiogenesis, and initiation of EMT. Here, we provide an overview of current research and approaches focusing on targeting components of the FGFR/FGF signaling module to overcome drug resistance during anti-cancer therapy.

Abstract

Increased expression of both FGF proteins and their receptors observed in many cancers is often associated with the development of chemoresistance, limiting the effectiveness of currently used anti-cancer therapies. Malfunctioning of the FGF/FGFR axis in cancer cells generates a number of molecular mechanisms that may affect the sensitivity of tumors to the applied drugs. Of key importance is the deregulation of cell signaling, which can lead to increased cell proliferation, survival, and motility, and ultimately to malignancy. Signaling pathways activated by FGFRs inhibit apoptosis, reducing the cytotoxic effect of some anti-cancer drugs. FGFRs-dependent signaling may also initiate angiogenesis and EMT, which facilitates metastasis and also correlates with drug resistance. Therefore, treatment strategies based on FGF/FGFR inhibition (using receptor inhibitors, ligand traps, monoclonal antibodies, or microRNAs) appear to be extremely promising. However, this approach may lead to further development of resistance through acquisition of specific mutations, metabolism switching, and molecular cross-talks. This review brings together information on the mechanisms underlying the involvement of the FGF/FGFR axis in the generation of drug resistance in cancer and highlights the need for further research to overcome this serious problem with novel therapeutic strategies.

FGF10/FGF17 as prognostic and drug response markers in acute myeloid leukemia

BACKGROUND

Fibroblast growth factors (FGFs) play important roles in solid tumor progression. Little is known about the function and the prognostic value of distinct FGFs in acute myeloid leukemia (AML).

METHODS

We used dataset from Beat AML to screen the FGFs family in AML by log-rank test. Subsequently, we identified the biological functions and the crucial signaling pathways associated with these screened FGFs using gene set enrichment analysis (GSEA). In addition, IC50 from 122 small-molecule inhibitors was used to explore the relationship between these signaling pathways and targets of sensitive inhibitors.

RESULTS

Among the FGFs family, over expressions of FGF10/FGF17 were found to be significantly associated with poor prognosis. FGF10 over expression was related to FLT3 and NPM1 mutations, and FGF17 over expression was linked to MUC12 and ZRSR2 mutations. Some cancer-related pathways such as PI3K-Akt, MAPK were significantly enriched by GSEA, and these pathways were concordant with sensitive inhibitors targeted pathways.

CONCLUSION

Our results indicated that FGF10 and FGF17 could be prognostic biomarkers for survivals of AML patients, and potential therapeutic targets for small-molecule inhibitors.

Molecular-driven treatment for biliary tract cancer: the promising turning point

INTRODUCTION

In the past, targeted therapies have not shown positive results as they have been used without adequate molecular selection of patients with biliary tract cancer (BTC). This has led to an expansion of research on characteristics and molecular selection to identify new effective strategies in this setting. Improved knowledge of the molecular biology of these neoplasms has highlighted their extraordinary heterogeneity and has made it possible to identify targetable gene alterations, including fibroblast growth factor receptor (FGFR) 2 gene fusions, and isocitrate dehydrogenase (IDH) mutations. The FDA recently approved ivosidenib and pemigatinib for the treatment of BTCs.

AREAS COVERED

We review data in the literature regarding targeted therapies for the treatment of BTCs, as well as on the prospects deriving from the extraordinary molecular heterogeneity of these neoplasms.

EXPERT OPINION

At present, it is essential to evaluate the expression of the genetic alterations expressed by these neoplasms to offer patients an increasingly personalized therapeutic approach. Studies are needed to better define the limits and potentials of targeted therapies and their role in the therapeutic algorithm to improve the poor prognosis of these patients.

DW14383 is an irreversible pan-FGFR inhibitor that suppresses FGFR-dependent tumor growth in vitro and in vivo

Fibroblast growth factor receptor (FGFR) is a promising anticancer target. Currently, most FGFR inhibitors lack sufficient selectivity and have nonnegligible activity against kinase insert domain receptor (KDR), limiting their feasibility due to the serious side effects. Notably, compensatory activation occurs among FGFR1-4, suggesting the urgent need to develop selective pan-FGFR1-4 inhibitors. Here, we explored the antitumor activity of DW14383, a novel irreversible FGFR1-4 inhibitor. DW14383 exhibited equivalently high potent inhibition against FGFR1, 2, 3 and 4, with IC₅₀ values of less than 0.3, 1.1, less than 0.3, and 0.5 nmol/L, respectively. It is a selective FGFR inhibitor, exhibiting more than 1100-fold selectivity for FGFR1 over recombinant KDR, making it one of the most selective FGFR inhibitors over KDR described to date. Furthermore, DW14383 significantly inhibited cellular FGFR1-4 signaling, inducing G1/S cell cycle arrest, which in turn antagonized FGFR-dependent tumor cell proliferation. In contrast, DW14383 had no obvious antiproliferative effect against cancer cell lines without FGFR aberration, further confirming its selectivity against FGFR. In representative FGFR-dependent xenograft models, DW14383 oral administration substantially suppressed tumor growth by simultaneously inhibiting tumor proliferation and angiogenesis via inhibiting FGFR signaling. In summary, DW14383 is a promising selective irreversible pan-FGFR inhibitor with pan-tumor spectrum potential in FGFR1-4 aberrant cancers, which has the potential to overcome compensatory activation among FGFR1-4.

The Role of Neutrophil Extracellular Traps in Cancer

Neutrophils are vital components of innate and adaptive immunity. It is widely acknowledged that in various pathological conditions, neutrophils are activated and release condensed DNA strands, triggering the formation of neutrophil extracellular traps (NETs). NETs have been shown to be effective in fighting against microbial infections and modulating the pathogenesis and progression of diseases, including malignant tumors. This review describes the current knowledge on the biological characteristics of NETs. Additionally, the mechanisms of NETs in cancer are discussed, including the involvement of signaling pathways and the crosstalk between other cancer-related mechanisms, including inflammasomes and autophagy. Finally, based on previous and current studies, the roles of NET formation and the potential therapeutic targets and strategies related to NETs in several well-studied types of cancers, including breast, lung, colorectal, pancreatic, blood, neurological, and cutaneous cancers, are separately reviewed and discussed.

Spatiotemporal sensitivity of mesoderm specification to FGFR signalling in the Drosophila embryo

Development of the Drosophila embryonic mesoderm is controlled through both internal and external inputs to the mesoderm. One such factor is Heartless (Htl), a Fibroblast Growth Factor Receptor (FGFR) expressed in the mesoderm. Although Htl has been extensively studied, the dynamics of its action are poorly understood after the initial phases of mesoderm formation and spreading. To begin to address this challenge, we have developed an optogenetic version of the FGFR Heartless in Drosophila (Opto-htl). Opto-htl enables us to activate the FGFR pathway in selective spatial (~ 35 μm section from one of the lateral sides of the embryo) and temporal domains (ranging from 40 min to 14 h) during embryogenesis. Importantly, the effects can be tuned by the intensity of light-activation, making this approach significantly more flexible than other genetic approaches. We performed controlled perturbations to the FGFR pathway to define the contribution of Htl signalling to the formation of the developing embryonic heart and somatic muscles. We find a direct correlation between Htl signalling dosage and number of Tinman-positive heart cells specified. Opto-htl activation favours the specification of Tinman positive cardioblasts and eliminates Eve-positive DA1 muscles. This effect is seen to increase progressively with increasing light intensity. Therefore, fine tuning of phenotypic responses to varied Htl signalling dosage can be achieved more conveniently than with other genetic approaches. Overall, Opto-htl is a powerful new tool for dissecting the role of FGFR signalling during development.

Emerging self-assembling peptide nanomaterial for anti-cancer therapy

Recently it is mainly focused on anti-tumor comprehensive treatments like finding target tumor cells or activating immune cells to inhibit tumor recurrence and metastasis. At present, chemotherapy and molecular-targeted drugs can inhibit tumor cell growth to a certain extent. However, multi-drug resistance and immune escape often make it difficult for new drugs to achieve expected effects. Peptide hydrogel nanoparticles is a new type of biological material with functional peptide chains as the core and self-assembling peptide (SAP) as the framework. It has a variety of significant biological functions, including effective local inflammation suppression and non-drug-resistant cell killing. Besides, it can induce immune activation more persistently in an adjuvant independent manner when compared with simple peptides. Thus, SAP nanomaterial has great potential in regulating cell physiological functions, drug delivery and sensitization, vaccine design and immunotherapy. Not only that, it is also a potential way to focus on some specific proteins and cells through peptides, which has already been examined in previous research. A full understanding of the function and application of SAP nanoparticles can provide a simple and practical strategy for the development of anti-tumor drugs and vaccine design, which contributes to the historical transition of peptide nanohydrogels from bench to bedside and brings as much survival benefits as possible to cancer patients.

Fibroblast Growth Factor Receptor (FGFR) Signaling in GIST and Soft Tissue Sarcomas

Sarcomas are a heterogeneous group of rare malignancies originating from mesenchymal tissues with limited therapeutic options. Recently, alterations in components of the fibroblast growth factor receptor (FGFR) signaling pathway have been identified in a range of different sarcoma subtypes, most notably gastrointestinal stromal tumors, rhabdomyosarcomas, and liposarcomas. These alterations include genetic events such as translocations, mutations, and amplifications as well as transcriptional overexpression. Targeting FGFR has therefore been proposed as a novel potential therapeutic approach, also in light of the clinical activity shown by multi-target tyrosine kinase inhibitors in specific subtypes of sarcomas. Despite promising preclinical evidence, thus far, clinical trials have enrolled very few sarcoma patients and the efficacy of selective FGFR inhibitors appears relatively low. Here, we review the known alterations of the FGFR pathway in sarcoma patients as well as the preclinical and clinical evidence for the use of FGFR inhibitors in these diseases. Finally, we discuss the possible reasons behind the current clinical data and highlight the need for biomarker stratification to select patients more likely to benefit from FGFR targeted therapies.

Tumor angiogenesis: Current challenges and therapeutic opportunities

Angiogenesis plays an important role in the development of cancer since it allows for the delivery of oxygen, nutrients, and growth factors as well as tumor dissemination to distant organs. Inhibition of angiogenesis is an important strategy for the prevention of multiple solid tumors that depend on cutting or at least reducing the blood supply to tumor micro-regions, resulting in pan-hypoxia and pan-necrosis within solid tumor tissues. These drugs are an important part of treatment for some types of cancer. As a stand-alone therapy, inhibition of tumor angiogenesis can arrest or halt tumor growth, but will not eliminate the tumor. Therefore, anti-angiogenic drugs in combinations with another anti-cancer treatment method, like chemotherapy, lead to being critical for optimum cancer patient outcomes. Over the last two decades, investigations have been made to improve the efficacy of anti-angiogenic drugs, recognize their potential in drug interactions, and come up with plausible explanations for possible treatment resistance. This review will offer an overview of the varying concepts of tumor angiogenesis, several important angiogenic factors; focus on the role of anti-angiogenesis strategies in cancer treatment.

Efficacy and Selectivity of FGF2-Saporin Cytosolically Delivered by PCI in Cells Overexpressing FGFR1

Fibroblast growth factor receptors (FGFRs) have become an attractive target in cancer research and therapy due to their implication in several cancers. Limitations of current treatment options require a need for additional, more specific and potent strategies to overcome cancers driven by FGFRs. Photochemical internalization (PCI) is a light-controlled method for cytosolic delivery of drugs that are entrapped in endosomes and lysosomes. We here evaluated the efficacy and selectivity of PCI of FGF2-saporin (FGF-SAP) in cells overexpressing FGFR1. FGF-SAP is a conjugate of FGF2 and the highly cytotoxic ribosome-inactivating protein (RIP) saporin, which is used as payload to eliminate cancer cells. Evaluation of the targeting effect of PCI of FGF-SAP was done by comparing the cytotoxic response in osteosarcoma cells with very low levels of FGFR1 (U2OS) to cells overexpressing FGFR1 (U2OS-R1). We demonstrate that PCI greatly enhances cytotoxicity of the drug showing efficient cell killing at pM concentrations of the drug in U2OS-R1 cells. However, U2OS cells were also sensitive to the toxin after PCI. Binding experiments using confocal microscopy and Western blotting techniques indicate that FGF-SAP is taken up by cells through heparan sulfate proteoglycans (HSPGs) in U2OS cells. We further show that the cytotoxicity of FGF-SAP in U2OS cells was reduced when cells were co-treated with heparin to compete out binding to HSPG, demonstrating that the cytotoxic effect was due to internalization by HSPGs. We conclude that to prevent off-target effects of FGF-based toxins, it will be necessary to circumvent binding to HSPGs, for example by mutating the binding site of FGF2 to HSPGs.

Role of FGF15 in Hepatic Surgery in the Presence of Tumorigenesis: Dr. Jekyll or Mr. Hyde?

The pro-tumorigenic activity of fibroblast growth factor (FGF) 19 (FGF15 in its rodent orthologue) in hepatocellular carcinoma (HCC), as well as the unsolved problem that ischemia-reperfusion (IR) injury supposes in liver surgeries, are well known. However, it has been shown that FGF15 administration protects against liver damage and regenerative failure in liver transplantation (LT) from brain-dead donors without tumor signals, providing a benefit in avoiding IR injury. The protection provided by FGF15/19 is due to its anti-apoptotic and pro-regenerative properties, which make this molecule a potentially beneficial or harmful factor, depending on the disease. In the present review, we describe the preclinical models currently available to understand the signaling pathways responsible for the apparent controversial effects of FGF15/19 in the liver (to repair a damaged liver or to promote tumorigenesis). As well, we study the potential pharmacological use that has the activation or inhibition of FGF15/19 pathways depending on the disease to be treated. We also discuss whether FGF15/19 non-pro-tumorigenic variants, which have been developed for the treatment of liver diseases, might be promising approaches in the surgery of hepatic resections and LT using healthy livers and livers from extended-criteria donors.

Role of fibroblast growth factor signalling in hepatic fibrosis

Fibrotic remodelling is a highly conserved protective response to tissue injury and it is essential for the maintenance of structural and functional tissue integrity. Also hepatic fibrosis can be considered as a wound-healing response to liver injury, reflecting a balance between liver repair and scar formation. In contrast, pathological fibrosis corresponds to impaired wound healing. Usually, the liver regenerates after acute injury. However, if the damaging mechanisms persist, the liver reacts with progressive and uncontrolled accumulation of extracellular matrix proteins. Eventually, excessive fibrosis can lead to cirrhosis and hepatic failure. Furthermore, cirrhosis is the major risk factor for the development of hepatocellular cancer (HCC). Therefore, hepatic fibrosis is the most critical pathological factor that determines the morbidity and mortality of patients with chronic liver disease. Still, no effective anti-fibrogenic therapies exist, despite the very high medical need. The regulation of fibroblast growth factor (FGF) signalling is a prerequisite for adequate wound healing, repair and homeostasis in various tissues and organs. The FGF family comprises 22 proteins that can be classified into paracrine, intracrine and endocrine factors. Most FGFs signal through transmembrane tyrosine kinase FGF receptors (FGFRs). Although FGFRs are promising targets for the treatment of HCC, the expression and function of FGFR-ligands in hepatic fibrosis is still poorly understood. This review summarizes the latest advances in our understanding of FGF signalling in hepatic fibrosis. Furthermore, the potential of FGFs as targets for the treatment of hepatic fibrosis and remaining challenges for the field are discussed.

Targeting the Fibroblast Growth Factor Receptor (FGFR) Family in Lung Cancer

Lung cancer is the most common cause of cancer-related deaths globally. Genetic alterations, such as amplifications, mutations and translocations in the fibroblast growth factor receptor (FGFR) family have been found in non-small cell lung cancer (NSCLC) where they have a role in cancer initiation and progression. FGFR aberrations have also been identified as key compensatory bypass mechanisms of resistance to targeted therapy against mutant epidermal growth factor receptor (EGFR) and mutant Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) in lung cancer. Targeting FGFR is, therefore, of clinical relevance for this cancer type, and several selective and nonselective FGFR inhibitors have been developed in recent years. Despite promising preclinical data, clinical trials have largely shown low efficacy of these agents in lung cancer patients with FGFR alterations. Preclinical studies have highlighted the emergence of multiple intrinsic and acquired resistance mechanisms to FGFR tyrosine kinase inhibitors, which include on-target FGFR gatekeeper mutations and activation of bypass signalling pathways and alternative receptor tyrosine kinases. Here, we review the landscape of FGFR aberrations in lung cancer and the array of targeted therapies under clinical evaluation. We also discuss the current understanding of the mechanisms of resistance to FGFR-targeting compounds and therapeutic strategies to circumvent resistance. Finally, we highlight our perspectives on the development of new biomarkers for stratification and prediction of FGFR inhibitor response to enable personalisation of treatment in patients with lung cancer.

Pentraxin 3 Inhibits the Angiogenic Potential of Multiple Myeloma Cells

Simple Summary

Bone marrow (BM) angiogenesis represents a key aspect in the progression of multiple myeloma (MM) and is strictly linked to the balance between pro-angiogenic and anti-angiogenic players produced by both neoplastic and stromal components. It has been shown that Fibroblast Growth Factors (FGFs) play a pivotal role in the angiogenic switch occurring during MM progression. Accordingly, the natural FGF antagonist Long Pentraxin 3 (PTX3) is able to reduce the activation of BM stromal components induced by FGFs. This work explores, for the first time, the anti-angiogenic role of PTX3 produced by MM cells demonstrating that the inducible expression of PTX3 is able to impair MM neovascularization, the onset of a proficient BM vascular niche and, ultimately, to impair tumor growth and dissemination.

Abstract

During multiple myeloma (MM) progression the activation of the angiogenic process represents a key step for the formation of the vascular niche, where different stromal components and neoplastic cells collaborate and foster tumor growth. Among the different pro-angiogenic players, Fibroblast Growth Factor 2 (FGF2) plays a pivotal role in BM vascularization occurring during MM progression. Long Pentraxin 3 (PTX3), a natural FGF antagonist, is able to reduce the activation of stromal components promoted by FGF2 in various in vitro models. An increased FGF/PTX3 ratio has also been found to occur during MM evolution, suggesting that restoring the “physiological” FGF/PTX3 ratio in plasma cells and BM stromal cells (BMSCs) might impact MM. In this work, taking advantage of PTX3-inducible human MM models, we show that PTX3 produced by tumor cells is able to restore a balanced FGF/PTX3 ratio sufficient to prevent the activation of the FGF/FGFR system in endothelial cells and to reduce the angiogenic capacity of MM cells in different in vivo models. As a result of this anti-angiogenic activity, PTX3 overexpression causes a significant reduction of the tumor burden in both subcutaneously grafted and systemic MM models. These data pave the way for the exploitation of PTX3-derived anti-angiogenic approaches in MM.

Targeted Therapies in Advanced Cholangiocarcinoma: A Focus on FGFR Inhibitors

Despite advanced diseases continuing to be associated with grim prognoses, the past decade has witnessed the advent of several novel treatment options for cholangiocarcinoma (CCA) patients. In fact, CCA has emerged as a heterogeneous group of malignancies harboring potentially druggable mutations in approximately 50% of cases, and thus, molecularly targeted therapies have been actively explored in this setting. Among these, fibroblast growth factor receptor (FGFR) inhibitors have reported important results, as witnessed by the FDA approval of pemigatinib in previously treated metastatic CCA patients harboring FGFR2 fusion or other rearrangements. Herein, we provide an overview of available evidence on FGFR inhibitors in CCA, especially focusing on the development, pitfalls and challenges of emerging treatments in this setting.

Chemical modification of NSC12 leads to a specific FGF-trap with antitumor activity in multiple myeloma

Inhibition of FGF/FGFR signaling is a promising strategy for the treatment of malignances dependent from FGF stimulation, including multiple myeloma (MM). The steroidal derivative NSC12 (compound 1) is a pan-FGF trap endowed with antitumor activity in vivo. Chemical modifications of compound 1 were explored to investigate structure-activity relationships, focusing on the role of the bis(trifluoromethyl)1,3-propanediol chain, the stereochemistry at C20 and functionalization of C3 position. Our studies unveiled compound 25b, the pregnane 3-keto 20R derivative of compound 1 as an effective agent, blocking the proliferation of MM cells in vitro by inhibiting FGF-dependent receptor activation and slowing MM growth in vivo. Importantly, the absence of the hydroxyl group at C3 prevents binding to estrogen receptors, which might concur to the antitumor activity observed for compound 1, leading to a specific FGF/FGFR system inhibitor, and further supporting the role of FGFR in anticancer therapy in MM.

Vascular Endothelial Growth Factor, a Key Modulator of the Anti-Tumor Immune Response

During tumor growth, angiogenesis is required to ensure oxygen and nutrient transport to the tumor. Vascular endothelial growth factor (VEGF) is the major inducer of angiogenesis and appears to be a key modulator of the anti-tumor immune response. Indeed, VEGF modulates innate and adaptive immune responses through direct interactions and indirectly by modulating protein expressions on endothelial cells or vascular permeability. The inhibition of the VEGF signaling pathway is clinically approved for the treatment of several cancers. Therapies targeting VEGF can modulate the tumor vasculature and the immune response. In this review, we discuss the roles of VEGF in the anti-tumor immune response. In addition, we summarize therapeutic strategies based on its inhibition, and their clinical approval.

FGFR inhibitors in elderly patients with advanced biliary tract cancer: an unsolved issue

Background: Despite recent advances in the understanding of the molecular landscape of biliary tract cancer (BTC), advanced disease continues to carry a poor prognosis, and the benefit from systemic treatments remains modest. However, BTCs have emerged as malignancies harboring specific potentially druggable aberrations, and thus, several molecularly targeted treatments have been recently tested. Among these, fibroblast growth factor receptor (FGFR) inhibitors have shown interesting results in previously treated BTC patients with advanced diseaseAreas covered: In this review, we aimed to provide an overview of available evidence on FGFR inhibitors in elderly patients with metastatic BTC, especially focusing on subgroup analyses of recently published trials exploring this novel therapeutic approach in these aggressive malignancies.Expert opinion: The FGFR1, FGFR2, and FGFR3 inhibitor pemigatinib has been recently approved by the United States Food and Drug Administration (FDA) in metastatic BTCs harboring FGFR2 fusion or other rearrangement. However, few data are available regarding the use of FGFR inhibitors in elderly BTCs, a patient population that remains seriously under-represented in clinical trials.

2b or Not 2b: How Opposing FGF Receptor Splice Variants Are Blocking Progress in Precision Oncology

More than ten thousand peer-reviewed studies have assessed the role of fibroblast growth factors (FGFs) and their receptors (FGFRs) in cancer, but few patients have yet benefited from drugs targeting this molecular family. Strategizing how best to use FGFR-targeted drugs is complicated by multiple variables, including RNA splicing events that alter the affinity of ligands for FGFRs and hence change the outcomes of stromal-epithelial interactions. The effects of splicing are most relevant to FGFR2; expression of the FGFR2b splice isoform can restore apoptotic sensitivity to cancer cells, whereas switching to FGFR2c may drive tumor progression by triggering epithelial-mesenchymal transition. The differentiating and regulatory actions of wild-type FGFR2b contrast with the proliferative actions of FGFR1 and FGFR3, and may be converted to mitogenicity either by splice switching or by silencing of tumor suppressor genes such as CDH1 or PTEN. Exclusive use of small-molecule pan-FGFR inhibitors may thus cause nonselective blockade of FGFR2 isoforms with opposing actions, undermining the rationale of FGFR2 drug targeting. This splice-dependent ability of FGFR2 to switch between tumor-suppressing and -driving functions highlights an unmet oncologic need for isoform-specific drug targeting, e.g., by antibody inhibition of ligand-FGFR2c binding, as well as for more nuanced molecular pathology prediction of FGFR2 actions in different stromal-tumor contexts.

A Pancancer Analysis of the Expression Landscape and Clinical Relevance of Fibroblast Growth Factor Receptor 2 in Human Cancers

Background: Fibroblast growth factor receptor 2 (FGFR2) is frequently altered in tumors and one of the top therapeutic targets in cholangiocarcinoma (CHOL) with FGFR2 fusions. Although there have been several studies on individual tumors, a comprehensive analysis of FGFR2 genetic aberrations and their simultaneous clinical implications across different tumors have not been reported. Methods: In this study, we used the large comprehensive datasets available, covering over 10,000 tumor samples across more than 30 cancer types, to analyze FGFR2 abnormal expression, methylation, alteration (mutations/fusions and amplification/deletion), and their clinical associations. Results: Alteration frequency, mutation location distribution, oncogenic effects, and therapeutic implications varied among different cancers. The overall mutation rate of FGFR2 is low in pancancer. CHOL had the highest mutation frequency, and fusion accounted for the major proportion. All these fusion aberrations in CHOL were targetable, and an FDA-approved drug was approved recently. Uterine corpus endometrial carcinoma (UCEC) had the highest number of FGFR2 mutations, and the most frequently mutated positions were S252W and N549K, where the functional impact was oncogenic, but targeted therapy was less effective. Additionally, DNA methylation was associated with FGFR2 expression in several cancers. Moreover, FGFG2 expression and genetic aberrations showed clinical associations with patient survival in several cancers, indicating their potential for application as new tumor markers and therapeutic targets. Conclusions: This study showed the full FGFR2 alteration spectrum and provided a broad molecular perspective of FGFR2 in a comprehensive manner, suggesting some new directions for clinical targeted therapy of cancers.

Targeting FGFR in non-small cell lung cancer: implications from the landscape of clinically actionable aberrations of FGFR kinases

OBJECTIVE

Dysfunction in fibroblast growth factor receptor (FGFR) signaling has been reported in diverse cancer types, including non-small cell lung cancer (NSCLC). The frequency of FGFR aberrations in Chinese NSCLC patients is therefore of great clinical significance.

METHODS

A total of 10,966 NSCLC patients whose tumor specimen and/or circulating cell-free DNA (cfDNA) underwent hybridization capture-based next-generation sequencing were reviewed. Patients' clinical characteristics and treatment histories were also evaluated.

RESULTS

FGFR aberrations, including mutations, fusions, and gene amplifications, were detected in 1.9% (210/10,966) of the population. FGFR abnormalities were more frequently observed in lung squamous cell carcinomas (6.8%, 65/954) than lung adenocarcinomas (1.3%, 128/9,596). FGFR oncogenic mutations were identified in 19 patients (~0.17%), of which, 68% were male lung squamous cell carcinoma patients. Eleven out of the 19 patients (58%) had concurrent altered PI3K signaling, thus highlighting a potential combination therapeutic strategy of dual-targeting FGFR and PI3K signaling in such patients. Furthermore, FGFR fusions retaining the intact kinase domain were identified in 12 patients (0.11%), including 9 FGFR3-TACC3, 1 FGFR2-INA, 1 novel FGFR4-RAPGEFL1, and 1 novel fusion between the FGFR1 and SLC20A2 5'-untranslated regions, which may have caused FGFR1 overexpressions. Concomitant EGFR mutations or amplifications were observed in 6 patients, and 4 patients received anti-EGFR inhibitors, in whom FGFR fusions may have mediated resistance to anti-EGFR therapies. FGFR amplification was detected in 24 patients, with the majority being FGFR1 amplifications. Importantly, FGFR oncogenic mutations, fusions, and gene amplifications were almost always mutually exclusive events.

CONCLUSIONS

We report the prevalence of FGFR anomalies in a large NSCLC population, including mutations, gene amplifications, and novel FGFR fusions.

Effects of metformin on lipopolysaccharide induced inflammation by activating fibroblast growth factor 21

Lipopolysaccharide (LPS) is a component of the cell wall of Gram-negative bacteria that produces endotoxemia, which may cause septic shock. Metformin (MET) is a widely used hypoglycemic drug that exhibits anti-inflammatory properties. Fibroblast growth factor 21 (FGF21) is an endocrine polypeptide that affects glucose and lipid metabolism, and also possesses anti-inflammatory properties. We investigated the effects of MET and FGF21 on inflammation due to LPS induced endotoxemia in male rats. Animals were divided into five groups: control, LPS, pre-MET LPS, LPS + 1 h MET and LPS + 3 h MET. Serum levels of alanine aminotransferase, aspartate aminotransferase, FGF2, interleukin-10 and tumor necrosis factor alpha were measured. Malondialdehyde, myeloperoxidase and FGF21 levels were measured in liver tissue samples. Histopathology of all groups was assessed using hematoxylin and eosin stained sections. LPS caused severe inflammatory liver damage. MET exhibited a partially protective effect and reduced inflammation significantly. FGF21 is produced in the liver following inflammation and MET may increase its production.

Fermentation, Purification, and Tumor Inhibition of a Disulfide-Stabilized Diabody Against Fibroblast Growth Factor-2

Angiogenesis is considered one of the hallmarks of cancer and plays a critical role in the development of tumor. Fibroblast growth factor 2 (FGF-2) is a member of the FGF family and participates in excessive cancer cell proliferation and tumor angiogenesis. Thus, targeting FGF-2 was considered to be a promising anti-tumor strategy. A disulfide-stabilized diabody (ds-Diabody) against FGF-2 was produced in Pichia pastoris (GS115) by fermentation and the anti-tumor activity was analyzed. The novel 10-L fed batch fermentation with newly designed media was established, and the maximum production of the ds-Diabody against FGF-2 reached 210.4 mg/L. The ds-Diabody against FGF-2 was purified by Ni²⁺ affinity chromatography and DEAE anion exchange chromatography. The recombinant ds-Diabody against FGF-2 could effectively inhibit proliferation, migration, and invasion of melanoma and glioma tumor cells stimulated by FGF-2. Furthermore, xenograft tumor model assays showed that the ds-Diabody against FGF-2 had potent antitumor activity in nude mice by inhibiting tumor growth and angiogenesis. The tumor growth inhibition rate of melanoma and glioma was about 70 and 45%, respectively. The tumor angiogenesis inhibition rate of melanoma and glioma was about 64 and 51%, respectively. The results revealed that the recombinant ds-Diabody against FGF-2 may be a promising anti-tumor drug for cancer therapy.

Pemigatinib: Hot topics behind the first approval of a targeted therapy in cholangiocarcinoma

Cholangiocarcinoma (CCA) includes a heterogeneous group of malignancies with limited treatment options. Despite recent advances in medical oncology, the prognosis of CCA patients with metastatic disease remains poor, with a median overall survival of less than a year. In the last decade, notable efforts have been made by the CCA medical community in an attempt to improve clinical outcomes of patients, with the development of molecularly targeted therapies in this setting. Among these treatments, the fibroblast growth factor receptor (FGFR) 2 inhibitor pemigatinib has received accelerated approval in April 2020 by the US Food and Drug Administration (FDA) in CCA patients harboring FGFR2 gene fusions or other rearrangements, on the basis of the results of the FIGHT-202 trial, and thus, representing the first molecularly targeted therapy to be approved for the treatment of CCA. However, several issues remain, including the emergence of polyclonal mutations determining resistance to pemigatinib, the identification of biomarkers predictive of response, and the knowledge gaps regarding the role of other FGFR gene aberrations. This review aims to provide an overview of recent development of pemigatinib, especially focusing on the results of the pivotal FIGHT-202 trial, the approval of this FGFR inhibitor, and the future challenges concerning the use of FGFR-directed treatments in CCA patients.

TGF-β1-mediated transition of resident fibroblasts to cancer-associated fibroblasts promotes cancer metastasis in gastrointestinal stromal tumor

Cancer-associated fibroblasts (CAFs) are the most abundant cells in the tumor microenvironment. Crosstalk between tumor cells and CAFs contributes to tumor survival in most epithelial cancers. Recently, utilizing gastrointestinal stromal tumor (GIST) as a model for sarcomas, we identified paracrine networks by which CAFs promote tumor progression and metastasis. However, the mechanisms by which CAFs arise in sarcomas remain unclear. Here, RNA sequencing analysis revealed that transforming growth factor-β1 (TGF-β1) is highly expressed in both tumor cells and CAFs. To determine the functional role of TGF-β1, we treated normal gastric fibroblasts (GFs) with recombinant TGF-β1, which caused the GFs to adopt a more stellate morphology, as well as increased the mRNA expression of CAF-mediated genes (CCL2, RAB3B, and TNC) and genes encoding fibroblast growth factors (FGFs). Moreover, while either GIST or CAF conditioned media enhanced the transition from GFs to CAFs, a TGF-β1-blocking antibody attenuated this effect. Transwell migration assays revealed that the TGF-β1-mediated transition from GFs to CAFs enhanced tumor cell migration. This migratory effect was abrogated by an anti-TGF-β1 antibody, suggesting that TGF-β1 secreted from GIST cells or CAFs is associated with GIST migration via GF-to-CAF transition. In addition, the murine spleen-to-liver metastasis model showed that GF pre-treated with TGF-β1 promoted GIST metastasis. Collectively, these findings reveal unappreciated crosstalk among tumor cells, CAFs, and normal resident fibroblasts in the stroma of sarcomas, which enhances a GF-to-CAF transition associated with tumor migration and metastasis.

Protopine/Gemcitabine Combination Induces Cytotoxic or Cytoprotective Effects in Cell Type-Specific and Dose-Dependent Manner on Human Cancer and Normal Cells

The natural alkaloid protopine (PRO) exhibits pharmacological properties including anticancer activity. We investigated the effects of PRO, alone and in combination with the chemotherapeutic gemcitabine (GEM), on human tumor cell lines and non-tumor human dermal fibroblasts (HDFs). We found that treatments with different PRO/GEM combinations were cytotoxic or cytoprotective, depending on concentration and cell type. PRO/GEM decreased viability in pancreatic cancer MIA PaCa-2 and PANC-1 cells, while it rescued the GEM-induced viability decline in HDFs and in tumor MCF-7 cells. Moreover, PRO/GEM decreased G1, S and G2/M phases, concomitantly with an increase of subG1 phase in MIA PaCa-2 and PANC-1 cells. Differently, PRO/GEM restored the normal progression of the cell cycle, altered by GEM, and decreased cell death in HDFs. PRO alone increased mitochondrial reactive oxygen species (ROS) in MIA PaCa-2, PANC-1 cells and HDFs, while PRO/GEM increased both intracellular and mitochondrial ROS in the three cell lines. These results indicate that specific combinations of PRO/GEM may be used to induce cytotoxic effects in pancreatic tumor MIA PaCa-2 and PANC-1 cells, but have cytoprotective or no effects in HDFs.

Molecular Basis of the Antiangiogenic Action of Rosmarinic Acid, a Natural Compound Targeting Fibroblast Growth Factor-2/FGFR Interactions

Fibroblast growth factor (FGF2)/fibroblast growth factor receptor (FGFR) signalling plays a major role both in physiology and in several pathologies, including cancer development, metastasis formation and resistance to therapy. The development of small molecules, acting extracellularly to target FGF2/FGFR interactions, has the advantage of limiting the adverse effects associated with current intracellular FGFR inhibitors. Herein, we discuss the ability of the natural compound rosmarinic acid (RA) to induce FGF2/FGFR complex dissociation. The molecular-level description of the FGF2/FGFR/RA system, by NMR spectroscopy and docking, clearly demonstrates that RA binds to the FGFR-D2 domain and directly competes with FGF2 for the same binding site. Direct and allosteric perturbations combine to destabilise the complex. The proposed molecular mechanism is validated by cellular studies showing that RA inhibits FGF2-induced endothelial cell proliferation and FGFR activation. Our results can serve as the basis for the development of new extracellular inhibitors of the FGF/FGFR pathways.

Inhibition of the FGF/FGFR System Induces Apoptosis in Lung Cancer Cells via c-Myc Downregulation and Oxidative Stress

Lung cancer represents an extremely diffused neoplastic disorder with different histological/molecular features. Among the different lung tumors, non-small-cell lung cancer (NSCLC) is the most represented histotype, characterized by various molecular markers, including the expression/overexpression of the fibroblast growth factor receptor-1 (FGFR1). Thus, FGF/FGFR blockade by tyrosine kinase inhibitors (TKi) or FGF-ligand inhibitors may represent a promising therapeutic approach in lung cancers. In this study we demonstrate the potential therapeutic benefit of targeting the FGF/FGFR system in FGF-dependent lung tumor cells using FGF trapping (NSC12) or TKi (erdafitinib) approaches. The results show that inhibition of FGF/FGFR by NSC12 or erdafitinib induces apoptosis in FGF-dependent human squamous cell carcinoma NCI-H1581 and NCI-H520 cells. Induction of oxidative stress is the main mechanism responsible for the therapeutic/pro-apoptotic effect exerted by both NSC12 and erdafitinib, with apoptosis being abolished by antioxidant treatments. Finally, reduction of c-Myc protein levels appears to strictly determine the onset of oxidative stress and the therapeutic response to FGF/FGFR inhibition, indicating c-Myc as a key downstream effector of FGF/FGFR signaling in FGF-dependent lung cancers.

Cytokines in oncolytic virotherapy

Tumors represent a hostile environment for the effector cells of cancer immunosurveillance. Immunosuppressive receptors and soluble or membrane-bound ligands are abundantly exposed and released by malignant entities and their stromal accomplices. As a consequence, executioners of antitumor immunity inefficiently navigate across cancer tissues and fail to eliminate malignant targets. By inducing immunogenic cancer cell death, oncolytic viruses profoundly reshape the tumor microenvironment. They trigger the local spread of danger signals and tumor-associated (as well as viral) antigens, thus attracting antigen-presenting cells, promoting the activation and expansion of lymphocytic populations, facilitating their infiltration in the tumor bed, and reinvigorating cytotoxic immune activity. The present review recapitulates key chemokines, growth factors and other cytokines that orchestrate this ballet of antitumoral leukocytes upon oncolytic virotherapy.

Fibroblast growth factor receptor signaling as therapeutic targets in female reproductive system cancers

Ovarian cancer, cervical cancer and endometrial cancer are three relatively common malignant cancers of the female reproductive system. Despite improvements in female genital tract cancer detection and development of new therapeutic approaches, there are still poor prognoses and some do not respond to therapeutic patterns, displaying low survival and high frequency of recurrence. In an era of personalized medicine, novel therapeutic approaches with greater efficacy for these cancers represent an unmet need. One of the actionable signaling pathways is the fibroblast growth factor receptor (FGFR) signaling pathway. Several mutations and alterations in FGF/FGFR family members have been reported in human cancers. FGF/FGFR signaling pathway has become a new target for cancer therapy. This review will summarize the role of FGFR pathway and the genetic alterations of the FGF/FGFR related to female reproductive system cancer. We will describe the available inhibitors of FGFR pathway for potential treatment of female reproductive system cancer. Furthermore, we will discuss FGFR-targeted therapies under clinical development for treatment of female reproductive system cancer.

Cyclodextrin inclusion complex inhibits circulating galectin-3 and FGF-7 and affects the reproductive integrity and mobility of Caco-2 cells

Galectin-3 (Gal-3) is a carbohydrate-binding protein, that promotes angiogenesis through mediating angiogenic growth factors such as vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF). There is strong evidence confirming FGF involvement in tumor growth and progression by disrupting cell proliferation and angiogenesis. In this study, we investigated the effect of β-cyclodextrin:everolimus:FGF-7 inclusion complex (Complex) on Caco-2 cell migration, cell motility and colony formation. In addition, we examined the inhibitory effect of the Complex on the circulating proteins; Gal-3 and FGF-7. Swiss Target Prediction concluded that Gal-3 and FGF are possible targets for β-CD. Results of the chemotaxis cell migration assay on Caco-2 cell line revealed that the Complex has higher reduction in cell migration (78.3%) compared to everolimus (EV) alone (58.4%) which is possibly due to the synergistic effect of these molecules when used as a combined treatment. Moreover, the Complex significantly decreased the cell motility in cell scratch assay, less than 10% recovery compared to the control which has ~ 45% recovery. The Complex inhibited colony formation by ~ 75% compared to the control. Moreover, the Complex has the ability to inhibit Gal-3 with minimum inhibitory concentration of 33.46 and 41 for β-CD and EV, respectively. Additionally, β-CD and β-CD:EV were able to bind to FGF-7 and decreased the level of FGF-7 more than 80% in cell supernatant. This confirms Swiss Target Prediction result that predicted β-CD could target FGF. These findings advance the understanding of the biological effects of the Complex which reduced cell migration, cell motility and colony formation and it is possibly due to inhibiting circulating proteins such as; Gal-3 and FGF-7.

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.

Hypoxia Induces Resistance to EGFR Inhibitors in Lung Cancer Cells via Upregulation of FGFR1 and the MAPK Pathway

Development of resistance remains the key obstacle to the clinical efficacy of EGFR tyrosine kinase inhibitors (TKI). Hypoxia is a key microenvironmental stress in solid tumors associated with acquired resistance to conventional therapy. Consistent with our previous studies, we show here that long-term, moderate hypoxia promotes resistance to the EGFR TKI osimertinib (AZD9291) in the non-small cell lung cancer (NSCLC) cell line H1975, which harbors two EGFR mutations including T790M. Hypoxia-induced resistance was associated with development of epithelial-mesenchymal transition (EMT) coordinated by increased expression of ZEB-1, an EMT activator. Hypoxia induced increased fibroblast growth factor receptor 1 (FGFR1) expression in NSCLC cell lines H1975, HCC827, and YLR086, and knockdown of FGFR1 attenuated hypoxia-induced EGFR TKI resistance in each line. Upregulated expression of FGFR1 by hypoxia was mediated through the MAPK pathway and attenuated induction of the proapoptotic factor BIM. Consistent with this, inhibition of FGFR1 function by the selective small-molecule inhibitor BGJ398 enhanced EGFR TKI sensitivity and promoted upregulation of BIM levels. Furthermore, inhibition of MEK activity by trametinib showed similar effects. In tumor xenografts in mice, treatment with either BGJ398 or trametinib enhanced response to AZD9291 and improved survival. These results suggest that hypoxia is a driving force for acquired resistance to EGFR TKIs through increased expression of FGFR1. The combination of EGFR TKI and FGFR1 or MEK inhibitors may offer an attractive therapeutic strategy for NSCLC. SIGNIFICANCE: Hypoxia-induced resistance to EGFR TKI is driven by overexpression of FGFR1 to sustain ERK signaling, where a subsequent combination of EGFR TKI with FGFR1 inhibitors or MEK inhibitors reverses this resistance. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/21/4655/F1.large.jpg.

Nintedanib inhibits keloid fibroblast functions by blocking the phosphorylation of multiple kinases and enhancing receptor internalization

Keloid is a benign skin tumor characterized by its cell hyperproliferative activity, invasion into normal skin, uncontrolled growth, overproduction and deposition of extracellular matrices and high recurrence rate after various therapies. Nintedanib is a receptor tyrosine kinase inhibitor targeting VEGF, PDGF, FGF, and TGF-β receptors with proved efficacy in anti-angiogenesis and in treating various types of cancers. In this study, we investigated the effects of nintedanib on keloid fibroblasts in both in vitro and ex vivo models. Keloid fibroblasts were prepared from 54 keloid scar samples in active stages collected from 49 patients. We found that nintedanib (1−4 μM) dose-dependently suppressed cell proliferation, induced G₀/G₁ cell cycle arrest, and inhibited migration and invasion of keloid fibroblasts. The drug also significantly inhibited the gene and protein expression of collagen I (COL-1) and III (COL-3), fibronectin (FN), and connective growth factor (CTGF), as well as the gene expression of other pathological factors, such as alpha smooth muscle actin (α-SMA), plasminogen activator inhibitor-1 (PAI-1), FK506-binding protein 10 (FKBP10), and heat shock protein 47 (HSP47) in keloid fibroblasts. Furthermore, nintedanib treatment significantly suppressed the phosphorylation of p38, JNK, ERK, STAT3, and Smad, enhanced endocytosis of various growth factor receptors. Using an ex vivo tissue explant model, we showed that nintedanib significantly suppressed cell proliferation, migration, and collagen production. The drug also significantly disrupted microvessel structure ex vivo. In summary, our results demonstrate that nintedanib is likely to become a potential targeted drug for keloid systemic therapy.

Kaempferol Improves TRAIL-Mediated Apoptosis in Leukemia MOLT-4 Cells by the Inhibition of Anti-apoptotic Proteins and Promotion of Death Receptors Expression

INTRODUCTION

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL or Apo2L) is a member of the Tumor Necrosis Factor (TNF) superfamily, which stimulates apoptosis in a wide range of cancer cells through binding to Death Receptors 4 and 5 (DR4/5). Nevertheless, TRAIL has noticeable anti-cancer abilities; some cancer cells acquire resistance to TRAIL, and consequently, its potential for inducing apoptosis in target cells is strongly diminished. Acute lymphoblastic leukemia MOLT-4 cell line is one of the most resistant cells to TRAIL that developed resistance to TRAIL through different pathways. TRAIL plus kaempferol was used to eliminate the resistance of the MOLT-4 cells to TRAIL.

MATERIALS AND METHODS

Firstly, IC50 for kaempferol (95μM) was determined by using the MTT assay. Secondly, the viability of the MOLT-4 cells was assayed by FACS after Annexin V/PI staining, following treatment with TRAIL (50 and 100nM) and kaempferol (95μM) alone and in combination. Finally, the expression levels of the candidate genes involved in resistance to TRAIL were assayed by real-time PCR technique.

RESULTS

Kaempferol plus TRAIL induced apoptosis robustly in MOLT-4 cells at 12, 24 and 48 hours after treatment. Additionally, it was found that kaempferol could inhibit the expression of c-FLIP, X-IAP, cIAP1/2, FGF-8 and VEGF-beta, and conversely augment the expression of DR4/5 in MOLT-4 cells.

CONCLUSION

It is suggested that co-treatment of MOLT-4 cells with TRAIL plus kaempferol is a practical and attractive approach to eliminate cancers' resistance to TRAIL by inhibition of the intracellular anti-apoptotic proteins, upregulation of DR4/5 and also by suppression of the VEGF-beta (VEGFB) and FGF-8 expressions.

Targeting the RANKL/RANK/OPG Axis for Cancer Therapy

RANKL and RANK are expressed in different cell types and tissues throughout the body. They were originally described for their essential roles in bone remodeling and the immune system but have subsequently been shown to provide essential signals from regulating mammary gland homeostasis during pregnancy to modulating tumorigenesis. The success of RANKL/RANK research serves as a paragon for translational research from the laboratory to the bedside. The case in point has been the development of Denosumab, a RANKL-blocking monoclonal antibody which has already helped millions of patients suffering from post-menopausal osteoporosis and skeletal related events in cancer. Here we will provide an overview of the pathway from its origins to its clinical relevance in disease, with a special focus on emerging evidence demonstrating the therapeutic value of targeting the RANKL/RANK/OPG axis not only in breast cancer but also as an addition to the cancer immunotherapy arsenal.