Mechanisms of FGFR-mediated carcinogenesis

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

Molecular dynamics simulations reveal phosphorylation-induced conformational dynamics of the fibroblast growth factor receptor 1 kinase

The Fibroblast Growth Factor Receptor1 (FGFR1) kinase wields exquisite control on cell fate, proliferation, differentiation, and homeostasis. An imbalance of FGFR1 signaling leads to several pathogeneses of diseases ranging from multiple cancers to allergic and neurodegenerative disorders. In this study, we investigated the phosphorylation-induced conformational dynamics of FGFR1 in apo and ATP-bound states via all-atom molecular dynamics simulations. All simulations were performed for 2 × 2 µs. We have also investigated the energetics of the binding of ATP to FGFR1 using the molecular mechanics Poisson-Boltzmann scheme. Our study reveals that the FGFR1 kinase can reach a fully active configuration through phosphorylation and ATP binding. A 3-10 helix formation in the activation loop signifies its rearrangement leading to stability upon ATP binding. The interaction of phosphorylated tyrosine (pTyr654) with positively charged residues forms strong salt-bridge interactions, driving the compactness of the structure. The dynamic cross-correlation map reveals phosphorylation enhances correlated motions and reduces anti-correlated motions between different domains. We believe that the mechanistic understanding of large-conformational changes upon the activation of the FGFR1 kinase will aid the development of novel targeted therapeutics.Communicated by Ramaswamy H. Sarma.

Identification of Piperazinyl-Difluoro-indene Derivatives Containing Pyridyl Groups as Potent FGFR Inhibitors against FGFR Mutant Tumor: Design, Synthesis, and Biological Evaluation

The fibroblast growth factor receptor (FGFR) signaling pathway plays important roles in cellular processes such as proliferation, differentiation, and migration. In this study, we highlighted the potential of FGFR inhibitors bearing the (S)-3,3-difluoro-1-(4-methylpiperazin-1-yl)-2,3-dihydro-1H-indene scaffold containing a crucial 3-pyridyl group for the treatment of FGFR mutant cancers. The representative compound (S)-23, which was identified through comprehensive evaluation, exhibited potent antiproliferative activity with GI50 in the range of 6.4-10.4 nM against FGFR1 fusion protein-carrying, FGFR2-amplified, and FGFR2 mutant cancer cell lines and good antiproliferative activity against FGFR3 translocation and mutant FGFR4 cancer cell lines, as well as potency assessment against FGFR1-4 kinases. Moreover, compound (S)-23 exhibited favorable pharmacokinetic properties, low potential for drug-drug interactions, and very potent antitumor activity in MFE-296 xenograft mouse models with a TGI of 99.1% at the dose of 10 mg/kg. These findings demonstrate that compound (S)-23 is a potential therapeutic agent for FGFR mutant tumors.

Histone methyltransferase SUV420H1/KMT5B contributes to poor prognosis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has a high rate of recurrence and poor prognosis, even after curative surgery. Multikinase inhibitors have been applied for HCC patients, but their effect has been restricted. This study aims to clarify the clinical impact of SUV420H1/KMT5B, one of the methyltransferases for histone H4 at lysine 20, and elucidate the novel mechanisms of HCC progression. We retrospectively investigated SUV420H1 expression using HCC clinical tissue samples employing immunohistochemical analysis (n = 350). We then performed loss-of-function analysis of SUV420H1 with cell cycle analysis, migration assay, invasion assay and RNA sequence for Gene Ontology (GO) pathway analysis in vitro, and animal experiments with xenograft mice in vivo. The SUV420H1-high-score group (n = 154) had significantly poorer prognosis for both 5-year overall and 2-year/5-year disease-free survival than the SUV420H1-low-score group (n = 196) (p < 0.001 and p < 0.05, respectively). The SUV420H1-high-score group had pathologically larger tumor size, more tumors, poorer differentiation, and more positive vascular invasion than the SUV420H1-low-score group. Multivariate analysis demonstrated that SUV420H1 high score was the poorest independent factor for overall survival. SUV420H1 knockdown could suppress cell cycle from G1 to S phase and cell invasion. GO pathway analysis showed that SUV420H1 contributed to cell proliferation, cell invasion, and/or metastasis. Overexpression of SUV420H1 clinically contributed to poor prognosis in HCC, and the inhibition of SUV420H1 could repress tumor progression and invasion both in vitro and in vivo; thus, further analyses of SUV420H1 are necessary for the discovery of future molecularly targeted drugs.

The Application of Artificial Intelligence and Drug Repositioning for the Identification of Fibroblast Growth Factor Receptor Inhibitors: A Review

Artificial intelligence talks about modeling intelligent behavior through a computer with the least human involvement. Drug repositioning techniques based on artificial intelligence accelerate the research process and decrease the cost of experimental studies. Dysregulation of fibroblast growth factor (FGF) receptors as the tyrosine kinase family of receptors plays a vital role in a wide range of malignancies. Because of their functional significance, they were considered promising drug targets for the therapy of various cancers. This review has summarized small molecules capable of inhibiting FGF receptors that progressed using artificial intelligence and repositioning drugs examined in clinical trials associated with cancer therapy. This review is based on a literature search in PubMed, Web of Science, Scopus EMBASE, and Google Scholar databases to gather the necessary information in each chapter by employing keywords like artificial intelligence, computational drug design, drug repositioning, and FGF receptor inhibitors. To achieve this goal, a spacious literature review of human studies in these fields-published over the last 20 decades-was performed. According to published reports, nonselective FGF receptor inhibitors can be used for cancer management, and multitarget kinase inhibitors are the first drug class approved due to more advanced clinical studies. For example, AZD4547 and BGJ398 are gradually entering the consumption cycle and are good options as combined treatments. Artificial intelligence and drug repositioning methods can help preselect suitable drug targets more successfully for future inhibition of carcinogenicity.

circNINL facilitates aerobic glycolysis, proliferation, invasion, and migration in lung cancer by sponging miR-3918 to mediate FGFR1 expression

Previously characterized as an oncogenic player in breast cancer, the function of circular RNA NINL (circNINL) in lung cancer (LC) remained elusive. This study aimed to delineate the biological role of circNINL in LC and to unveil its potential molecular mechanisms. We discovered elevated expression levels of circNINL and Fibroblast Growth Factor Receptor 1 (FGFR1) concomitant with diminished expression of microRNA-3918 (miR-3918) in LC specimens. Knockdown of circNINL led to a marked decrease in cell proliferation, migration, invasion, and aerobic glycolysis, alongside an upsurge in apoptosis in LC cells. Either downregulation of miR-3918 or overexpression of FGFR1 mitigated the suppressive impact of circNINL knockdown on LC pathogenesis. Mechanistic studies validated that circNINL served as a competitive endogenous RNA for miR-3918, thus influencing FGFR1 expression. Further, in vivo experiments using nude mouse xenograft models underscored that silencing circNINL substantially curtailed tumor growth in LC. Collectively, these findings illuminate that circNINL exacerbates LC malignancy via the miR-3918/FGFR1 axis, a process integrally linked with the activation of aerobic glycolysis.

Chemotherapeutic Activity of Imidazolium-Supported Pd(II) o-Vanillylidene Diaminocyclohexane Complexes Immobilized in Nanolipid as Inhibitors for HER2/neu and FGFR2/FGF2 Axis Overexpression in Breast Cancer Cells

Two bis-(imidazolium-vanillylidene)-(R,R)-diaminocyclohexane ligands (H2(VAN)2dach, H2L1,2) and their Pd(II) complexes (PdL1 and PdL2) were successfully synthesized and structurally characterized using microanalytical and spectral methods. Subsequently, to target the development of new effective and safe anti-breast cancer chemotherapeutic agents, these complexes were encapsulated by lipid nanoparticles (LNPs) to formulate (PdL1LNP and PdL2LNP), which are physicochemically and morphologically characterized. PdL1LNP and PdL2LNP significantly cause DNA fragmentation in MCF-7 cells, while trastuzumab has a 10% damaging activity. Additionally, the encapsulated Pd1,2LNPs complexes activated the apoptotic mechanisms through the upregulated P53 with p < 0.001 and p < 0.05, respectively. The apoptotic activity may be triggered through the activity mechanism of the Pd1,2LNPs in the inhibitory actions against the FGFR2/FGF2 axis on the gene level with p < 0.001 and the Her2/neu with p < 0.05 and p < 0.01. All these aspects have triggered the activity of the PdL1LNP and PdL2LNP to downregulate TGFβ1 by p < 0.01 for both complexes. In conclusion, LNP-encapsulated Pd(II) complexes can be employed as anti-cancer drugs with additional benefits in regulating the signal mechanisms of the apoptotic mechanisms among breast cancer cells with chemotherapeutic-safe actions.

Combined treatment with crizotinib and temsirolimus is an effective strategy in mantle cell lymphoma and can overcome acquired resistance to temsirolimus

Constitutive activation of the PI3K/AKT/mTOR-pathway plays an important role in the pathogenesis of mantle cell lymphoma (MCL), leading to approval of the mTOR inhibitor temsirolimus for relapsed or refractory MCL. Yet, despite favorable initial response rates, early relapses under treatment have been observed. Therefore, understanding the underlying mechanisms of temsirolimus resistance and developing strategies to overcome it is highly warranted. Here, we established a new temsirolimus-resistant MCL cell line to evaluate the molecular background of resistance to this drug. Transcriptome profiling and gene set enrichment analysis comparing temsirolimus-sensitive and -resistant cell lines showed significant upregulation of PI3K/AKT/mTor-, RAS signaling- and the RTK-dependent PDGFR-, FGFR-, Met- and ALK-signaling-pathways in the resistant cells. Furthermore, MET, known as important proto-oncogene and mediator of drug resistance, was among the most upregulated genes in the resistant cells. Importantly, Met protein was overexpressed in both, MCL cells with acquired as well as intrinsic temsirolimus resistance, but could not be detected in any of the temsirolimus sensitive ones. Combined pharmacological inhibition of mTOR and Met signaling with temsirolimus and the RTK inhibitor crizotinib significantly restored sensitivity to temsirolimus. Furthermore, this combined treatment proved to be synergistic in all MCL cell lines investigated and was also active in primary MCL cells. In summary, we showed for the first time that overexpression of MET plays an important role for mediating temsirolimus resistance in MCL and combined treatment with temsirolimus and crizotinib is a very promising therapeutic approach for MCL and an effective strategy to overcome temsirolimus resistance.

Comprehensive interrogation of gene lists from genome-scale cancer screens with oncoEnrichR

Genome-scale screening experiments in cancer produce long lists of candidate genes that require extensive interpretation for biological insight and prioritization for follow-up studies. Interrogation of gene lists frequently represents a significant and time-consuming undertaking, in which experimental biologists typically combine results from a variety of bioinformatics resources in an attempt to portray and understand cancer relevance. As a means to simplify and strengthen the support for this endeavor, we have developed oncoEnrichR, a flexible bioinformatics tool that allows cancer researchers to comprehensively interrogate a given gene list along multiple facets of cancer relevance. oncoEnrichR differs from general gene set analysis frameworks through the integration of an extensive set of prior knowledge specifically relevant for cancer, including ranked gene-tumor type associations, literature-supported proto-oncogene and tumor suppressor gene annotations, target druggability data, regulatory interactions, synthetic lethality predictions, as well as prognostic associations, gene aberrations and co-expression patterns across tumor types. The software produces a structured and user-friendly analysis report as its main output, where versions of all underlying data resources are explicitly logged, the latter being a critical component for reproducible science. We demonstrate the usefulness of oncoEnrichR through interrogation of two candidate lists from proteomic and CRISPR screens. oncoEnrichR is freely available as a web-based service hosted by the Galaxy platform (https://oncotools.elixir.no), and can also be accessed as a stand-alone R package (https://github.com/sigven/oncoEnrichR).

FGF21-FGFR1 controls mitochondrial homeostasis in cardiomyocytes by modulating the degradation of OPA1

Fibroblast growth factor 21 (FGF21) is a pleiotropic hormone secreted primarily by the liver and is considered a major regulator of energy homeostasis. Recent research has revealed that FGF21 could play an important role in cardiac pathological remodeling effects and prevention of cardiomyopathy; however, the underlying mechanism remains largely unknown. This study aimed to determine the mechanism underlying the cardioprotective effects of FGF21. We engineered FGF21 knock out mice and subsequently elucidated the effects of FGF21 and its downstream mediators using western blotting, qRT-PCR, and mitochondrial morphological and functional analyses. FGF21 knockout mice showed cardiac dysfunction, accompanied by a decline in global longitudinal strain (GLS) and ejection fraction (EF), independent of metabolic disorders. Mitochondrial quality, quantity, and function were abnormal, accompanied by decreased levels of optic atrophy-1 (OPA1) in FGF21 KO mice. In contrast to FGF21 knockout, cardiac-specific overexpression of FGF21 alleviated the cardiac dysfunction caused by FGF21 deficiency. In an in vitro study, FGF21 siRNA deteriorated mitochondrial dynamics and impaired function induced by cobalt chloride (CoCl₂). Both recombinant FGF21 and adenovirus-mediated FGF21 overexpression could alleviate CoCl₂-induced mitochondrial impairment by restoring mitochondrial dynamics. FGF21 was essential for maintaining mitochondrial dynamics and function of the cardiomyocytes. As a regulator of cardiomyocyte mitochondrial homeostasis under oxidative stress, FGF21 could be an important new target for therapeutic options for patients with heart failure.

MicroRNA-377: A therapeutic and diagnostic tumor marker

Cancer is considered as one of the main causes of human deaths globally. Despite the recent progresses in therapeutic modalities, there is still a high rate of mortality among cancer patients. Late diagnosis in advanced tumor stages is one of the main reasons for treatment failure in cancer patients. Therefore, it is required to suggest the novel strategies for the early tumor detection. MicroRNAs (miRNAs) have critical roles in neoplastic transformation by regulation of cell proliferation, migration, and apoptosis. They are always considered as non-invasive markers due to their high stability in body fluids. Since, all of the miRNAs have tissue-specific functions in different tumors as tumor suppressor or oncogene; it is required to investigate the molecular mechanisms of every miRNA in different tumors to introduce that as a suitable non-invasive diagnostic marker in cancer patients. For the first time in the present review, we discussed the role of miR-377 during tumor progression. It has been reported that miR-377 mainly functions as a tumor suppressor through the regulation of signaling pathways and transcription factors. This review is an important step toward introducing the miR-377 as a novel diagnostic marker as well as a therapeutic target in cancer patients.

FORT-1: Phase II/III Study of Rogaratinib Versus Chemotherapy in Patients With Locally Advanced or Metastatic Urothelial Carcinoma Selected Based on FGFR1/3 mRNA Expression

PURPOSE

Rogaratinib, an oral pan-fibroblast growth factor receptor (FGFR1-4) inhibitor, showed promising phase I efficacy and safety in patients with advanced urothelial carcinoma (UC) with FGFR1-3 mRNA overexpression. We assessed rogaratinib efficacy and safety versus chemotherapy in patients with FGFR mRNA-positive advanced/metastatic UC previously treated with platinum chemotherapy.

METHODS

FORT-1 (ClinicalTrials.gov identifier: NCT03410693) was a phase II/III, randomized, open-label trial. Patients with FGFR1/3 mRNA-positive locally advanced or metastatic UC with ≥ 1 prior platinum-containing regimen were randomly assigned (1:1) to rogaratinib (800 mg orally twice daily, 3-week cycles; n = 87) or chemotherapy (docetaxel 75 mg/m2, paclitaxel 175 mg/m2, or vinflunine 320 mg/m2 intravenously once every 3 weeks; n = 88). The primary end point was overall survival, with objective response rate (ORR) analysis planned following phase II accrual. Because of comparable efficacy between treatments, enrollment was stopped before progression to phase III; a full interim analysis of phase II was completed.

RESULTS

ORRs were 20.7% (rogaratinib, 18/87; 95% CI, 12.7 to 30.7) and 19.3% (chemotherapy, 17/88; 95% CI, 11.7 to 29.1). Median overall survival was 8.3 months (95% CI, 6.5 to not estimable) and 9.8 months (95% CI, 6.8 to not estimable; hazard ratio, 1.11; 95% CI, 0.71 to 1.72; P = .67). Grade 3/4 events occurred in 37 (43.0%)/4 (4.7%) patients and 32 (39.0%)/15 (18.3%), respectively. No rogaratinib-related deaths occurred. Exploratory analysis of patients with FGFR3 DNA alterations showed ORRs of 52.4% (11/21; 95% CI, 29.8 to 74.3) for rogaratinib and 26.7% (4/15; 95% CI, 7.8 to 55.1) for chemotherapy.

CONCLUSION

To our knowledge, these are the first data to compare FGFR-directed therapy with chemotherapy in patients with FGFR-altered UC, showing comparable efficacy and manageable safety. Exploratory testing suggested FGFR3 DNA alterations in association with FGFR1/3 mRNA overexpression may be better predictors of rogaratinib response.

Advances in Lung Cancer Treatment Using Nanomedicines

Carcinoma of the lungs is among the most menacing forms of malignancy and has a poor prognosis, with a low overall survival rate due to delayed detection and ineffectiveness of conventional therapy. Therefore, drug delivery strategies that may overcome undesired damage to healthy cells, boost therapeutic efficacy, and act as imaging tools are currently gaining much attention. Advances in material science have resulted in unique nanoscale-based theranostic agents, which provide renewed hope for patients suffering from lung cancer. Nanotechnology has vastly modified and upgraded the existing techniques, focusing primarily on increasing bioavailability and stability of anti-cancer drugs. Nanocarrier-based imaging systems as theranostic tools in the treatment of lung carcinoma have proven to possess considerable benefits, such as early detection and targeted therapeutic delivery for effectively treating lung cancer. Several variants of nano-drug delivery agents have been successfully studied for therapeutic applications, such as liposomes, dendrimers, polymeric nanoparticles, nanoemulsions, carbon nanotubes, gold nanoparticles, magnetic nanoparticles, solid lipid nanoparticles, hydrogels, and micelles. In this Review, we present a comprehensive outline on the various types of overexpressed receptors in lung cancer, as well as the various targeting approaches of nanoparticles.

Fibroblast growth factor 21 and prognosis of patients with cardiovascular disease: A meta-analysis

BACKGROUND

The role of fibroblast growth factor 21 (FGF21) in predicting the long-term prognosis of patients with cardiovascular disease (CVD) remains unknown.

METHODS

A comprehensive search in PubMed, Embase, and the Cochrane Library was performed to identify studies reporting the association between FGF21 and prognosis among patients with CVD. A meta-analysis was performed, with patients stratified by coronary artery disease (CAD) or heart failure (HF). The endpoint of CAD or HF was major adverse cardiovascular events defined by each study and a composite of death or HF readmission, respectively. The I² method and linear regression test of funnel plot asymmetry were used to test heterogeneity (I² > 50% indicates substantial heterogeneity) and publication bias (asymmetry P < 0.05, indicating publication bias).

RESULTS

A total of 807 records were retrieved, and nine studies were finally included. Higher FGF21 levels were significantly associated with the risk of major adverse cardiovascular events in patients with CAD (multivariate hazard ratio [HR]: 1.77, 95% confidence interval [CI]: 1.40-2.23, P < 0.05, I² = 0%, fixed-effect model). Increased FGF21 levels were also associated with the risk of all-cause death among patients with CAD (multivariate HR: 2.67, 95% CI: 1.25-5.72, P < 0.05, I² = 64%, random-effect model). No association was found between FGF21 and the endpoint among patients with HF (HR: 1.57, 95% CI: 0.99-2.48, P > 0.05, random-effect model), but a large heterogeneity (I² = 95%) and potential publication bias (Asymmetry P < 0.05) existed in the analysis.

CONCLUSION

Increased FGF21 levels were independently associated with poor prognosis of CAD, whereas the role of FGF21 in predicting clinical outcomes of HF requires further investigation.

Targeting FGFRs for tumor therapy: current status and novel strategies

The FGF receptors (FGFRs) belong to a family of receptor tyrosine kinases. Abundant evidence shows that FGFRs are closely related to tumor cell invasion and angiogenesis. Hence, targeted modulation of FGFRs has become an effective strategy for cancer treatment. Recently, the development of small-molecule inhibitors targeting FGFRs has been extensively studied, and three inhibitors have been approved for marketing. Based on the clinical problems with the current inhibitors, there is a need to develop novel inhibitors and technologies to address the pitfalls. This review summarizes recent advances in small-molecule inhibitors targeting FGFRs, focusing on structure-activity relationships. Moreover, recent progress of novel technologies are summarized to provide a reference for promoting the application of drugs targeting FGFRs in tumor therapy.

Patient Selection Approaches in FGFR Inhibitor Trials-Many Paths to the Same End?

Inhibitors of fibroblast growth factor receptor (FGFR) signaling have been investigated in various human cancer diseases. Recently, the first compounds received FDA approval in biomarker-selected patient populations. Different approaches and technologies have been applied in clinical trials, ranging from protein (immunohistochemistry) to mRNA expression (e.g., RNA in situ hybridization) and to detection of various DNA alterations (e.g., copy number variations, mutations, gene fusions). We review, here, the advantages and limitations of the different technologies and discuss the importance of tissue and disease context in identifying the best predictive biomarker for FGFR targeting therapies.

A novel small molecule RK-019 inhibits FGFR2-amplification gastric cancer cell proliferation and induces apoptosis in vitro and in vivo

Gastric cancer (GC) is one of the most malignant cancers and is estimated to be fifth in incidence ratio and the third leading cause of cancer death worldwide. Despite advances in GC treatment, poor prognosis and low survival rate necessitate the development of novel treatment options. Fibroblast growth factor receptors (FGFRs) have been suggested to be potential targets for GC treatment. In this study, we report a novel selective FGFR inhibitor, RK-019, with a pyrido [1, 2-a] pyrimidinone skeleton. In vitro, RK-019 showed excellent FGFR1-4 inhibitory activities and strong anti-proliferative effects against FGFR2-amplification (FGFR2-amp) GC cells, including SNU-16 and KATO III cells. Treatment with RK-019 suppressed phosphorylation of FGFR and its downstream pathway proteins, such as FRS2, PLCγ, AKT, and Erk, resulting in cell cycle arrest and induction of apoptosis. Furthermore, daily oral administration of RK-019 could attenuate tumor xenograft growth with no adverse effects. Here, we reported a novel specific FGFR inhibitor, RK-019, with potent anti-FGFR2-amp GC activity both in vitro and in vivo.

FGF/FGFR signaling in adrenocortical development and tumorigenesis: novel potential therapeutic targets in adrenocortical carcinoma

FGF/FGFR signaling regulates embryogenesis, angiogenesis, tissue homeostasis and wound repair by modulating proliferation, differentiation, survival, migration and metabolism of target cells. Understandably, compelling evidence for deregulated FGF signaling in the development and progression of different types of tumors continue to emerge and FGFR inhibitors arise as potential targeted therapeutic agents, particularly in tumors harboring aberrant FGFR signaling. There is first evidence of a dual role of the FGF/FGFR system in both organogenesis and tumorigenesis, of which this review aims to provide an overview. FGF-1 and FGF-2 are expressed in the adrenal cortex and are the most powerful mitogens for adrenocortical cells. Physiologically, they are involved in development and maintenance of the adrenal gland and bind to a family of four tyrosine kinase receptors, among which FGFR1 and FGFR4 are the most strongly expressed in the adrenal cortex. The repeatedly proven overexpression of these two FGFRs also in adrenocortical cancer is thus likely a sign of their participation in proliferation and vascularization, though the exact downstream mechanisms are not yet elucidated. Thus, FGFRs potentially offer novel therapeutic targets also for adrenocortical carcinoma, a type of cancer resistant to conventional antimitotic agents.

Network Dynamics Caused by Genomic Alteration Determine the Therapeutic Response to FGFR Inhibitors for Lung Cancer

Recently, FGFR inhibitors have been highlighted as promising targeted drugs due to the high prevalence of FGFR1 amplification in cancer patients. Although various potential biomarkers for FGFR inhibitors have been suggested, their functional effects have been shown to be limited due to the complexity of the cancer signaling network and the heterogenous genomic conditions of patients. To overcome such limitations, we have reconstructed a lung cancer network model by integrating a cell line genomic database and analyzing the model in order to understand the underlying mechanism of heterogeneous drug responses. Here, we identify novel genomic context-specific candidates that can increase the efficacy of FGFR inhibitors. Furthermore, we suggest optimal targets that can induce more effective therapeutic responses than that of FGFR inhibitors in each of the FGFR-resistant lung cancer cells through computational simulations at a system level. Our findings provide new insights into the regulatory mechanism of differential responses to FGFR inhibitors for optimal therapeutic strategies in lung cancer.

Fibroblast growth factor receptor 3 overexpression mediates ALK inhibitor resistance in ALK-rearranged non-small cell lung cancer

The rearrangement of anaplastic lymphoma kinase (ALK) occurs in 3%‐5% of patients with non–small cell lung cancer (NSCLC) and confers sensitivity to ALK–tyrosine kinase inhibitors (TKIs). For the treatment of patients with ALK‐rearranged NSCLC, various additional ALK‐TKIs have been developed. Ceritinib is a second‐generation ALK‐TKI and has shown great efficacy in the treatment of patients with both newly diagnosed and crizotinib (a first‐generation ALK‐TKI)‐refractory ALK‐rearranged NSCLC. However, tumors can also develop ceritinib resistance. This may result from secondary ALK mutations, but other mechanisms responsible for this have not been fully elucidated. In this study, we explored the mechanisms of ceritinib resistance by establishing ceritinib‐resistant, echinoderm microtubule‐associated protein‐like 4 (EML4)‐ALK–positive H3122 cells and ceritinib‐resistant patient‐derived cells. We identified a mechanism of ceritinib resistance induced by bypass signals that is mediated by the overexpression and activation of fibroblast growth factor receptor 3 (FGFR3). FGFR3 knockdown by small hairpin RNA or treatment with FGFR inhibitors was found to resensitize the resistant cells to ceritinib in vitro and in vivo. FGFR ligands from either human serum or fetal bovine serum were able to activate FGFR3 and induce ceritinib resistance. A detailed analysis of ceritinib‐resistant patient‐derived specimens confirmed that tyrosine‐protein kinase Met (cMET) amplification induces ceritinib resistance. Amplified cMET counteractivated EGFR and/or Her3 and induced ceritinib resistance. These results reveal multiple ceritinib resistance mechanisms and suggest that ceritinib resistance might be overcome by identifying precise resistance mechanisms.

Genomic Relevance of FGFR2 on the Prognosis of HCV-Induced Hepatocellular Carcinoma Patients

The Fibroblast Growth Factor Receptors (FGFRs) are known to regulate cancer metabolism in different tumor types, including hepatocellular carcinoma (HCC). Several risk factors are associated with HCC, of which viral infections (Hepatitis B and C) and cirrhosis are prominent. In Pakistan as well as in highly developed countries like the United States, hepatitis C virus HCV infections are most commonly reported in HCC. Here, we aimed to investigate the clinical relevance of FGFR receptors in HCC and their role in HCV-positive HCC cases. 264 HCC samples along with their clinical information and 96 normal liver samples were collected. qPCR was done to estimate the expression of FGFR1, FGFR2, FGFR3 and FGFR4. Three independent HCV-induced HCC cohorts (containing 293 HCC samples) were used for validation. According to in vitro results, FGFR1 was upregulated in HCV+ HCC patients. However, in all three independent cohorts of HCC, significant a down-regulation of FGFR1 was observed. FGFR2 overexpression was observed in the in vitro cohort as well as in three independent HCC cohorts. Interestingly, a strong correlation of FGFR2 expression was observed between cirrhosis and HCV in all four HCC cohorts. Our study suggested that FGFR2 expression can be used to classify HCC patients based on HCV infection. This FGFR2-based classification may lead to new therapeutic strategies against HCV-positive HCC subtypes.

Inhibition of Fibroblast Growth Factor Receptor Attenuates Ultraviolet B-Induced Skin Carcinogenesis

Altered FGFR signaling has been shown to play a role in a number of cancers. However, the role of FGFR signaling in the development and progression of ultraviolet B-induced (UVB) induced cutaneous squamous cell carcinoma (cSCC) remains unclear. In the current study, the effect of UVB radiation on FGFR activation and its downstream signaling in mouse skin epidermis was examined. In addition, the impact of FGFR inhibition on UVB-induced signaling and skin carcinogenesis was also investigated. Exposure of mouse dorsal skin to UVB significantly increased phosphorylation of FGFRs in the epidermis as well as activation of downstream signaling pathways, including AKT/mTOR, STATs and MAPK. Topical application of the pan-FGFR inhibitor AZD4547 to mouse skin prior to exposure to UVB significantly inhibited FGFR phosphorylation as well as mTORC1, STAT3 and MAPK activation (i.e., phosphorylation). Moreover, AZD4547 pretreatment significantly inhibited UVB-induced epidermal hyperplasia and hyperproliferation and reduced infiltration of mast cells and macrophages into the dermis. AZD4547 treatment also significantly inhibited mRNA expression of inflammatory genes in the epidermis. Finally, mice treated topically with AZD4547 prior to UVB exposure showed decreased cSCC incidence and increased survival rate. Collectively, the current data supports the hypothesis that inhibition of FGFR in epidermis may provide a new strategy to prevent and/or treat UVB-induced cSCC.

Fibroblast Growth Factor Receptor 1-4 Genetic Aberrations as Clinically Relevant Biomarkers in Squamous Cell Lung Cancer

Fibroblast growth factor receptor (FGFR) inhibitors (FGFRis) are a potential therapeutic option for squamous non-small cell lung cancer (Sq-NSCLC). Because appropriate patient selection is needed for targeted therapy, molecular profiling is key to discovering candidate biomarker(s). Multiple FGFR aberrations are present in Sq-NSCLC tumors-alterations (mutations and fusions), amplification and mRNA/protein overexpression-but their predictive potential is unclear. Although FGFR1 amplification reliability was unsatisfactory, FGFR mRNA overexpression, mutations, and fusions are promising. However, currently their discriminatory power is insufficient, and the available clinical data are from small groups of Sq-NSCLC patients. Here, we focus on FGFR aberrations as predictive biomarkers for FGFR-targeting agents in Sq-NSCLC. Known and suggested molecular determinants of FGFRi resistance are also discussed.

Human Growth Factor/Immunoglobulin Complexes for Treatment of Myocardial Ischemia-Reperfusion Injury

Hepatocyte Growth Factor (HGF) and Fibroblast Growth Factor 2 (FGF2) are receptor tyrosine kinase agonists that promote cell survival after tissue injury and angiogenesis, cell proliferation and migration during tissue repair and regeneration. Both ligands have potential as systemic treatments for ischemia-reperfusion injury, however clinical use of HGF and FGF2 has been limited by poor pharmacokinetic profiles, i.e., their susceptibility to serum proteases, rapid clearance and short half-lives. Previously, we reported vaso- and cardioprotective protein complexes formed between HGF and polyclonal, non-specific immunoglobulin (IgG) with therapeutic efficacy in a rat model of myocardial ischemia with reperfusion (MI/R). Here, using a pre-clinical porcine MI/R model, we demonstrate human HGF/IgG complexes provide significant myocardial salvage, reduce infarct size, and are detectable in myocardial tissue 24 h after intracoronary injection. Furthermore, we show that multiple daily infusions of HGF/IgG complexes after MI do not lead to production of HGF-specific auto-antibodies, an important concern for administered biologic drugs. In experiments to identify other growth factors that non-covalently interact with IgG, we found that human FGF2 associates with IgG. Similar to human HGF/IgG complexes, FGF2/IgG complexes protected primary human cardiac endothelial cells under simulated ischemia (1% oxygen and nutrient deprivation) for 48–72 h. Molecular modeling studies suggested that FGF2 and HGF both interact with the Fc domain of IgG. Also, we tested whether an Fc-fusion protein would bind FGF2 to form complexes. By native gel electrophoretic assays and biochemical pulldowns, we found that Jagged1, a Notch1 ligand that controls stem cell self-renewal and tissue regeneration, bound FGF2 when presented as a Jagged1- Fc fusion protein. Our results suggest that human growth factor/IgG and FGF2/Fc- fusion complexes have potential to provide a biologics platform to treat myocardial ischemia-reperfusion and other forms of tissue injury.

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.

A phase 1 study of LY3076226, a fibroblast growth factor receptor 3 (FGFR3) antibody-drug conjugate, in patients with advanced or metastatic cancer

Background We report a Phase 1 study of LY3076226, an antibody-drug conjugate composed of human IgG1 monoclonal antibody against the human FGFR3 attached with a cleavable linker to the maytansine derivative DM4 in patients with advanced or metastatic cancer. Methods This study was comprised of two parts: (A) dose escalation in patients with advanced or metastatic cancer and (B) dose expansion in patients with urothelial carcinoma with locally determined FGFR3 alterations. The dose range of LY3076226 tested was 0.2-5.0 mg/kg as an intravenous infusion on Day 1 of each 21-day cycle. The primary objective was to determine a recommended phase 2 dose (RP2D). Results Twenty-five patients were enrolled (Part A: 22, Part B: 3) and received ≥ 1 dose of LY3076226. No dose-limiting toxicities were reported. LY3076226 was generally well tolerated; most of the toxicities were Grade 1 or 2. Two patients experienced treatment-related Grade 3 toxicity (embolism and decreased platelet count). Four patients experienced serious adverse events (not treatment-related), all in Part A. Dose-proportional exposure was observed, with an estimated half-life of 2-7 days. No responses were seen with LY3076226 treatment. Stable disease persisting for > 6 months was observed in 1 patient receiving 3.2 mg/kg of LY3076226. Conclusion The study demonstrates acceptable safety and tolerability of LY3076226 up to the 5.0 mg/kg dose. Recruitment was stopped due to pipeline prioritization. Dose escalation of LY3076226 beyond 5.0 mg/kg in patients with advanced tumors may be possible. The trial was registered on August 19, 2015 under identifier NCT02529553 with ClinicalTrials.gov.

Biological Significance and Targeting of the FGFR Axis in Cancer

Simple Summary

All cells within tissues and organ systems must communicate with each other to ensure they function in a coordinated manner. One form of communication is signalling mediated by small proteins (for example fibroblast growth factors; FGFs) that are secreted by one cell and bind to specialised receptors (for example FGF receptors) on nearby cells. These receptors propagate the signal to the nucleus of the receiving cell, which in turn dictates to the cell how it should react. FGFR signalling is versatile, tightly controlled and important for normal body homeostasis, facilitating growth, healing and replacing old cells. However, cancer cells can take command of this pathway and use it to their advantage. This review will first explain the biology of FGFR signalling and then describe how it can be corrupted, the implications in cancer, and how it can be targeted to improve cancer therapy.

Abstract

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.

A cyclic peptide retards the proliferation of DU145 prostate cancer cells in vitro and in vivo through inhibition of FGFR2

In malignancies, fibroblast growth factor receptors (FGFRs) signaling is reinforced through overexpression of fibroblast growth factors (FGFs) or their receptors. FGFR2 has been proposed as a target for cancer therapy, because both the expression and activation of FGFR2 are boosted in various malignant carcinomas. Although several chemicals have been designed against FGFR2, they did not exhibit enough specificity and might bring potential accumulated toxicity. In this study, we developed an epitope peptide (P5) and its cyclic derivative (DcP5) based on the structure of FGF2 to limit the activation of FGFR2. The anticancer activities of P5 and DcP5 were examined in vitro and in vivo. Our results demonstrated that P5 significantly inhibited the cell proliferation in FGFR2‐dependent manner in DU145 cells and retarded tumor growth in DU145 xenograft model with negligible toxicity toward normal organs. Further investigations found that the Gln4 and Glu6 residues of P5 bind to FGFR2 to abolish its activation. Moreover, we developed the P5 cyclic derivative, DcP5, which achieved reinforced stability and anticancer activity in vivo. Our findings suggest P5 and its cyclic derivative DcP5 as potential candidates for anticancer therapy.

Real-world efficacy and safety of anlotinib as third- or further-line treatment in refractory small cell lung cancer

PURPOSE

As a novel antiangiogenic multi-target tyrosine kinase inhibitor recently approved in China, anlotinib has exhibited promising anticancer efficacy and acceptable safety profile in the salvage treatment of small cell lung cancer (SCLC) in clinical trials. Here we retrospectively investigated the efficacy and safety of anlotinib as third- or further-line treatment in patients with refractory SCLC.

PATIENTS AND METHODS

A total of 40 patients with refractory SCLC treated with anlotinib monotherapy were included in this study. The clinicopathological data, treatment information, survival data and safety data were retrospectively collected. Survival curves were constructed using the Kaplan-Meier method. Univariate analysis was performed by log-rank testing.

RESULTS

Altogether, 40 patients of extensive-stage SCLC or progressive limited-stage SCLC received anlotinib monotherapy as third- or further-line treatment from July 2018 to June 2020. Four patients achieved partial response (PR), 14 patients achieved stable disease (SD), no complete response (CR) was recorded, and 22 patients experienced progressive disease (PD). The disease control rate (DCR) was 45.0%. The median progression-free survival (PFS) was 3.0 months (95% CI 2.241-3.759), and the median overall survival (OS) was 7.8 months (95% CI 3.190-12.410). The common adverse effects (AEs) included hypertension, fatigue, anorexia, cough, rash and nausea. Grade 3 treatment-related AEs occurred in 3 (7.5%) patients. One patient interrupted anlotinib treatment due to repeated grade 1 epistaxis. Univariate analysis revealed that patients without liver metastases, previously treated with radiotherapy or with Eastern Cooperative Oncology Group (ECOG) scores of 0 or 1 had longer OS with anlotinib treatment. Cox regression analysis demonstrated that patients without liver metastases and patients with ECOG score ≤ 1 had longer PFS, while patients without liver metastases had longer OS.

CONCLUSION

Anlotinib is beneficial to refractory SCLC as third- or further-line treatment, especially in patients without liver metastasis and with better physical status. Related adverse effects are tolerable and manageable.

Circular RNA regulates the onset and progression of cancer through the mitogen-activated protein kinase signaling pathway

The rapid increase in cancer morbidity and mortality worldwide is a major challenge for public health providers. Therefore, there is an urgent need to explore the molecular mechanism of tumorigenesis and identify potential diagnostic biomarkers and therapeutic methods. Circular RNA (circRNA) is characterized by a stable structure and tissue-specific expression; these features are useful in medical research and clinical applications. In recent years, with the development of high-throughput sequencing technology, the potential use of circRNA in cancer prognosis and treatment has been extensively explored. Abnormal circRNA expression interferes with specific signaling pathways such as the MAPK pathway; this phenomenon may provide potential diagnostic biomarkers and new therapeutic targets. The present article discusses the research progress on the regulatory roles of MAPK/ERK pathway-related circRNA molecules in the development and progression of different types of tumors. This review may provide insight into the development of circRNA-based cancer management strategies.

The Evolving Role of FGFR2 Inhibitors in Intrahepatic Cholangiocarcinoma: From Molecular Biology to Clinical Targeting

Intrahepatic cholangiocarcinoma (iCCA) is an anatomically and biologically distinct entity with a rising incidence and a poor prognosis on conventional treatments. Surgery followed by adjuvant chemotherapy is a potentially curative option in resectable cases, while palliative-intent chemotherapy is the standard-of-care in the advanced setting. Technological advances through massive parallel sequencing have enabled a deeper understanding of disease biology with the identification of several druggable molecular vulnerabilities in nearly 50% of cases. Among them, gene fusions involving the fibroblast growth factor receptor 2 (FGFR2) are the most therapeutically exploited so far with a number of Phase II clinical trials investigating FGFR2 inhibitors showing unprecedented efficacy results in this molecular subgroup. Over the last year, these efforts have culminated in the US FDA-approval of pemigatinib and infigratinib, the first two oral selective FGFR2 targeted agents for previously treated, locally advanced or metastatic iCCA driven by FGFR2 fusion or rearrangements. While first-line Phase III trials are currently underway to test these targeted approach against standard-of-care chemotherapy, translational studies are trying to better understand primary and secondary resistance mechanisms in order to optimize FGFR2 blockade in iCCA. In this article, we extensively reviewed the current evidence on the biological rationale, as well as preclinical and clinical development of FGFR inhibitors in iCCA.

Comprehending fibroblast growth factor receptor like 1: Oncogene or tumor suppressor?

Fibroblast Growth Factor Receptor Like 1 (FGFRL1) signaling has crucial role in a multitude of processes during genetic diseases, embryonic development and various types of cancer. Due to its partial structural similarity with its classical Fibroblast Growth Factor Receptor [FGFR] counterparts and lack of tyrosine kinase domain, FGFRL1 was thought to work as a decoy receptor in FGF/FGFR signaling. Later on, growing number evidences showed that expression of FGFRL1 affects major pathways like ERK1/2, Akt and others, which are dysfunctional in a wide range of human cancers. In this review, we provide an overview of the current understanding of FGFRL1 and its roles in cell differentiation, adhesion and proliferation pathways . Overexpression of FGFRL1 might lead to tumor progression and invasion. In this context, inhibitors for FGFRL1 might have therapeutic benefits in human cancer prognosis.

Modeling the effects of EMT-immune dynamics on carcinoma disease progression

During progression from carcinoma in situ to an invasive tumor, the immune system is engaged in complex sets of interactions with various tumor cells. Tumor cell plasticity alters disease trajectories via epithelial-to-mesenchymal transition (EMT). Several of the same pathways that regulate EMT are involved in tumor-immune interactions, yet little is known about the mechanisms and consequences of crosstalk between these regulatory processes. Here we introduce a multiscale evolutionary model to describe tumor-immune-EMT interactions and their impact on epithelial cancer progression from in situ to invasive disease. Through simulation of patient cohorts in silico, the model predicts that a controllable region maximizes invasion-free survival. This controllable region depends on properties of the mesenchymal tumor cell phenotype: its growth rate and its immune-evasiveness. In light of the model predictions, we analyze EMT-inflammation-associated data from The Cancer Genome Atlas, and find that association with EMT worsens invasion-free survival probabilities. This result supports the predictions of the model, and leads to the identification of genes that influence outcomes in bladder and uterine cancer, including FGF pathway members. These results suggest new means to delay disease progression, and demonstrate the importance of studying cancer-immune interactions in light of EMT.

Development of a human antibody fragment directed against the alpha folate receptor as a promising molecule for targeted application

Alpha folate receptor (FRα) is currently under investigation as a target for the treatment of patients with non-small-cell lung cancer (NSCLC), since it is highly expressed in tumor cells but is largely absent in normal tissue. In this study, a novel human variable domain of a heavy-chain (VH) antibody fragment specific to FRα was enriched and selected by phage bio-planning. The positive phage clone (3A102 VH) specifically bound to FRα and also cross-reacted with FRβ, as tested by ELISA. Clone 3A102 VH was then successfully expressed as a soluble protein in an E. coli shuffle strain. The obtained soluble 3A102 VH demonstrated a high affinity for FRα with affinity constants (K_aff) values around 7.77 ± 0.25 × 10⁷ M⁻¹, with specific binding against both FRα expressing NSCLC cells and NSCLC patient-derived primary cancer cells, as tested by cell ELISA. In addition, soluble 3A102 VH showed the potential desired property of a targeting molecule by being internalized into FRα-expressing cells, as observed by confocal microscopy. This study inspires the use of phage display to develop human VH antibody (Ab) fragments that might be well suited for drug targeted therapy of NSCLC and other FRα-positive cancer cells.

Multiple Therapeutic Applications of RBM-007, an Anti-FGF2 Aptamer

Vascular endothelial growth factor (VEGF) plays a pivotal role in angiogenesis, but is not the only player with an angiogenic function. Fibroblast growth factor-2 (FGF2), which was discovered before VEGF, is also an angiogenic growth factor. It has been shown that FGF2 plays positive pathophysiological roles in tissue remodeling, bone health, and regeneration, such as the repair of neuronal damage, skin wound healing, joint protection, and the control of hypertension. Targeting FGF2 as a therapeutic tool in disease treatment through clinically useful inhibitors has not been developed until recently. An isolated inhibitory RNA aptamer against FGF2, named RBM-007, has followed an extensive preclinical study, with two clinical trials in phase 2 and phase 1, respectively, underway to assess the therapeutic impact in age-related macular degeneration (wet AMD) and achondroplasia (ACH), respectively. Moreover, showing broad therapeutic potential, preclinical evidence supports the use of RBM-007 in the treatment of lung cancer and cancer pain.

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.

Transcriptomic signals in blood prior to lung cancer focusing on time to diagnosis and metastasis

Recent studies have indicated that there are functional genomic signals that can be detected in blood years before cancer diagnosis. This study aimed to assess gene expression in prospective blood samples from the Norwegian Women and Cancer cohort focusing on time to lung cancer diagnosis and metastatic cancer using a nested case–control design. We employed several approaches to statistically analyze the data and the methods indicated that the case–control differences were subtle but most distinguishable in metastatic case–control pairs in the period 0–3 years prior to diagnosis. The genes of interest along with estimated blood cell populations could indicate disruption of immunological processes in blood. The genes identified from approaches focusing on alterations with time to diagnosis were distinct from those focusing on the case–control differences. Our results support that explorative analyses of prospective blood samples could indicate circulating signals of disease-related processes.

Atractylenolide III predisposes miR-195-5p/FGFR1 signaling axis to exert tumor-suppressive functions in liver cancer

BACKGROUND

Antineoplastic activity of atractylenolide III (ATL) has been reported in several malignant tumors. However, its activity has not been completely clarified in hepatocellular carcinoma (HCC). Herein, anticancer effects and underlying molecular mechanisms of ATL were investigated in HCC cells in vitro.

METHODS

Cell viability was evaluated by CCK-8 assay. Cell migration and invasion were evaluated using the transwell assay. TUNEL staining was performed to evaluate cell apoptosis. Protein expression was measured by western blotting analysis. Online database TargetScan and luciferase reporter gene analysis were performed to validate FGFR1 as a target of miR-195-5p.

RESULTS

HepG2 and SMMC7721 cell growth, migration, and invasion were inhibited by ATL treatment in a dose-dependent pattern. ATL treatment-induced apoptosis of HepG2 and SMMC7721 cells. Intriguingly, ATL treatment unexpectedly inhibited FGFR1 protein expression in HepG2 and SMMC7721 cells. Knockdown of FGFR1 inhibited proliferation, migration, and invasion, and evoked apoptosis of HepG2 and SMMC7721 cells. We also found that ATL treatment could increase the expression of miR-195-5p, which as a posttranscriptional targeted FGFR1. In HCC tissues, miR-195-5p expression is negatively correlated with FGFR1. Furthermore, the antiproliferative and proapoptotic roles of miR-195-5p were neutralized by overexpressed FGFR1 in HCC cells.

CONCLUSION

ATL effectively repressed growth and induced apoptosis of human HCC cells through the upregulation of miR-195-5p to downregulate FGFR1 expression.

PRACTICAL APPLICATIONS

Atractylenolide III as a bioactive anticancer adjuvant medication will provide chemosensitization strategy for reversing the drug resistance of HCC.

Gene Expression Landscape of SDH-Deficient Gastrointestinal Stromal Tumors

BACKGROUND

About 20-40% of gastrointestinal stromal tumors (GISTs) lacking KIT/PDGFRA mutations show defects in succinate dehydrogenase (SDH) complex. This study uncovers the gene expression profile (GEP) of SDH-deficient GIST in order to identify new signaling pathways or molecular events actionable for a tailored therapy.

METHODS

We analyzed 36 GIST tumor samples, either from formalin-fixed, paraffin-embedded by microarray or from fresh frozen tissue by RNA-seq, retrospectively collected among KIT-mutant and SDH-deficient GISTs. Pathway analysis was performed to highlight enriched and depleted transcriptional signatures. Tumor microenvironment and immune profile were also evaluated.

RESULTS

SDH-deficient GISTs showed a distinct GEP with respect to KIT-mutant GISTs. In particular, SDH-deficient GISTs were characterized by an increased expression of neural markers and by the activation of fibroblast growth factor receptor signaling and several biological pathways related to invasion and tumor progression. Among them, hypoxia and epithelial-to-mesenchymal transition emerged as features shared with SDH-deficient pheochromocytoma/paraganglioma. In addition, the study of immune landscape revealed the depletion of tumor microenvironment and inflammation gene signatures.

CONCLUSIONS

This study provides an update of GEP in SDH-deficient GISTs, highlighting differences and similarities compared to KIT-mutant GISTs and to other neoplasm carrying the SDH loss of function. Our findings add a piece of knowledge in SDH-deficient GISTs, shedding light on their putative histology and on the dysregulated biological processes as targets of new therapeutic strategies.

Co-expression of fibroblast growth factor receptor 3 with mutant p53, and its association with worse outcome in oropharyngeal squamous cell carcinoma

Fibroblast growth factor receptor 3 (FGFR3) is expressed in squamous cell carcinoma of the head and neck (SCCHN) including oropharyngeal squamous cell carcinoma (OPSCC) and is a potential therapeutic target. However, information on its correlation with other relevant cancer related proteins stratified by p16 status and its prognostic significance in OPSCC is limited. We examined FGFR3 expression and its correlation with clinical characteristics, p16 status, and mutant p53 (mp53) among 220 retrospectively collected OPSCC cases and 40 prospectively collected SCCHN cases, including a majority of OPSCC. Correlations of FGFR3 Weighted Index (WI) with p16 status and mp53 WI as well as its association with disease-free survival (DFS) and overall survival (OS) were evaluated. FGFR3 expression was detected in 61% and 70% of cases in cohorts 1 and 2, respectively. FGFR3 level was significantly higher in p16-negative tumors in both cohorts (p<0.001 and 0.006). FGFR3 expression was highly correlated with mp53 expression in both p16 + and p16- OPSCC (p<0.0001 and p = 0.0006, respectively). In cohort 1, univariate analysis showed that FGFR3 was associated with DFS but not OS. Kaplan-Meier analysis showed that higher FGFR3 and mp53 level correlated with worse DFS (p = 0.025) and OS (p = 0.009). As expected, p16 positive status was associated with improved OS and DFS (p<0.001 for both). Our results suggest that high FGFR3 expression is associated with p16 negative status and mp53 expression in OPSCC and correlates with a worse clinical outcome. The biological relationship between FGFR3 and mp53 in OPSCC deserves further investigation.

Cutaneous Cancer Biology

There has been a drastic increase in the incidence of nonmelanoma (NMSC), including squamous, basal cell, and melanoma skin cancers worldwide. Most cases of skin cancer can be treated effectively with surgery; fewer than 10% of cases are advanced and may require additional therapies. A better understanding of the biology of skin cancer will help contribute to better prognostic information and identification of possible new therapeutic targets. Herein, the authors review the biology and pathogenesis of both NMSC and melanoma, focusing on critical cell signaling pathways mediating the disease and current therapeutic strategies targeted to underlying genetic pathways.

Oxysophocarpine suppresses FGFR1-overexpressed hepatocellular carcinoma growth and sensitizes the therapeutic effect of lenvatinib

AIMS

Hepatocellular carcinoma (HCC) is an aggressive solid tumor with restricted therapeutics. Lenvatinib is the second approved frontline drug for advanced HCC, however lenvatinib-resistant cases have been reported in clinical. Overexpression of fibroblast growth factor receptor (FGFR1) has been found to be associated with advanced HCC. This study was aimed to investigate the relationship between FGFR1 overexpression and lenvatinib resistance, and explore the potential candidate that can sensitize lenvatinib against FGFR1-overexpressed HCC.

MAIN METHODS

Development of FGFR1 overexpression was accomplished in Hep3B and HepG2 cell lines by pCDH-FGFR1 lentiviral vector. In vitro, cell proliferation, colony formation, cell migration and cell apoptosis assays were used to explore the effect of lenvatinib and Oxysophocarpine. In vivo, BALB/c nude mice were burdened with subcutaneous FGFR1-overexpressed Hep3B tumor to assess the therapeutic effect of lenvatinib and Oxysophocarpine. qRT-PCR and western blotting were further used to identify the underlying mechanism.

KEY FINDINGS

Here, we revealed that overexpressed FGFR1 and its downstream AKT/mTOR and ERK signaling activation could induce lenvatinib resistance in HCC. In vivo and in vitro results showed Oxysophocarpine inhibited the proliferation and induced the apoptosis of FGFR1-overexpressed HCC cells. Oxysophocarpine could further sensitize FGFR1-overexpressed HCC cells to lenvatinib treatment. Mechanism studies revealed that Oxysophocarpine downregulated FGFR1 expression along with downstream AKT/mTOR and ERK signaling to sensitize lenvatinib against FGFR1-overexpressed HCC.

SIGNIFICANCES

These data collectively provided evidence that FGFR1 overexpression could be a potential cause of lenvatinib resistance and Oxysophocarpine could be an ideal combined therapy with lenvatinib in HCC treatment.

Cellular and molecular mechanisms in fibrosis

The activation of fibroblasts is required for physiological tissue remodelling such as wound healing. However, when the regulatory mechanisms are disrupted and fibroblasts remain persistently activated, the progressive deposition of extracellular matrix proteins leads to tissue fibrosis, which results in dysfunction or even loss of function of the affected organ. Although fibrosis has been recognized as a major cause of morbidity and mortality in modern societies, there are only few treatment options available that directly disrupt the release of extracellular matrix from fibroblasts. Intensive research in recent years, however, identified several pathways as core fibrotic mechanisms that are shared across different fibrotic diseases and organs. We discuss herein selection of those core pathways, especially downstream of the profibrotic TGF-β pathway, which are druggable and which may be transferable from bench to bedside.

The Expression and Prognostic Value of FGF2, FGFR3, and FGFBP1 in Esophageal Squamous Cell Carcinoma

Background

Esophageal squamous cell carcinoma was treated by operation and chemoradiotherapy. However, the prognosis of most patients is poor after treatment, and most studies have shown that FGF2 and its receptor (FGFR) are involved in the development of various malignant tumors. FGF2 plays an important role in tumor progression and malignancy. In this study, the immunohistochemistry of FGF2, FGFR3, and FGFBP1 was used to further verify the expression of the three proteins in 172 patients with esophageal squamous cell carcinoma (ESCC) who had not received preoperative chemoradiotherapy and its effect on the prognosis of ESCC.

Methods

(1) χ ² test was used to analyze the relationship between proteins and clinicopathological parameters. Survival analysis was used to investigate the effect of three proteins on prognosis. (2) Paired sample t-test was used to analyze the mRNA expression of the three proteins in fresh ESCC tissues and adjacent normal tissues.

Results

FGF2 was correlated with tumor size (p = 0.026), gender (p = 0.047), and lymph metastasis (p = 0.007) in ESCC tissues. The high expression of FGFR3 was associated with tumor differentiation (p = 0.043 and p < 0.05), lymph node metastasis (p = 0.078 and p < 0.1), and race (p = 0.033 and p < 0.05). The high expression of FGFBP1 was significantly associated with the degree of tumor differentiation (p = 0.012), age (p = 0.045), and lymph node metastasis (p = 0.032) of ESCC patients. The expression of FGF2, FGFR3, and FGFBP1-mRNA in ESCC tissues was significantly higher than that in adjacent tissues (p < 0.001, p < 0.001, and p = 0.001). Patients with high expression of FGF2, FGFBP1, and FGFR3 had poor prognosis. There was a weak positive correlation between FGF2 and FGFBP1, as well as FGFR.

Conclusion

The FGF2-FGFR3 axis may promote the progression of esophageal squamous cell carcinoma. The FGF2-FGFR3 axis may be a new direction of targeted therapy for esophageal squamous cell carcinoma. FGF2 and FGFR3 may be used as prognostic markers of esophageal squamous cell carcinoma.

FGF2: a novel druggable target for glioblastoma?

Introduction: Fibroblast growth factors (FGFs) are key mitogens in tissue homeostasis and cancer. FGF2 regulates self-renewal of multiple stem-cell types, is widely used in stem cell culture paradigms and has been adopted for cultivating the growth of cancer stem cells ex vivo. Research has shed light on the functions of FGF2 in brain tumors, particularly malignant glioma, and this has demonstrated that FGF2 increases self-renewal of glioblastoma stem cells.Areas covered: This review examines the potential targeting of FGF2 signaling as a possible treatment avenue for glioblastoma. The expression of FGF ligands and the FGFR family of receptor tyrosine kinases in the normal brain and in glioblastoma is described. Moreover, the paper sheds light on FGF/FGFR signaling, including the function of heparin/heparan sulfate proteoglycans in facilitating FGF signaling. We speculate on potential avenues for the therapeutic targeting of the FGF2-FGF receptor signaling axis in glioblastoma and the associated challenges envisioned with these approaches.Expert opinion: Precision targeting of FGF/FGFR signaling could improve prospective glioblastoma therapeutics and moderate adverse effects. Shrewd development of experimental models and FGF2 inhibitors could provide a 'pharmacological toolbox' for targeting diverse ligand/receptor combinations.

Loss of function of NF1 is a mechanism of acquired resistance to endocrine therapy in lobular breast cancer

Background

Invasive lobular carcinoma (ILC) as a disease entity distinct from invasive ductal carcinoma (IDC) has merited focused studies of the genomic landscape, but those to date are largely limited to the assessment of early-stage cancers. Given that genomic alterations develop as acquired resistance to endocrine therapy, studies on refractory ILC are needed.

Patients and methods

Tissue from 336 primary-enriched, breast-biopsied ILC and 485 estrogen receptor (ER)-positive IDC and metastatic biopsy specimens from 180 ILC and 191 ER-positive IDC patients was assayed with hybrid-capture-based comprehensive genomic profiling for short variant, indel, copy number variants, and rearrangements in up to 395 cancer-related genes.

Results

Whereas ESR1 alterations are enriched in the metastases of both ILC and IDC compared with breast specimens, NF1 alterations are enriched only in ILC metastases (mILC). NF1 alterations are predominantly under loss of heterozygosity (11/14, 79%), are mutually exclusive with ESR1 mutations [odds ratio = 0.24, P < 0.027] and are frequently polyclonal in ctDNA assays. Assessment of paired specimens shows that NF1 alterations arise in the setting of acquired resistance. An in vitro model of CDH1 mutated ER-positive breast cancer demonstrates that NF1 knockdown confers a growth advantage in the presence of 4-hydroxy tamoxifen. Our study further identified a significant increase in tumor mutational burden (TMB) in mILCs relative to breast ILCs or metastatic IDCs (8.9% >20 mutations/mb; P < 0.001). Most TMB-high mILCs harbor an APOBEC trinucleotide signature (14/16; 88%).

Conclusions

This study identifies alteration of NF1 as enriched specifically in mILC. Mutual exclusivity with ESR1 alterations, polyclonality in relapsed ctDNA, and de novo acquisition suggest a role for NF1 loss in endocrine therapy resistance. Since NF1 loss leads to RAS/RAF kinase activation, patients may benefit from a matched inhibitor. Moreover, for an independent subset of mILC, TMB was elevated relative to breast ILC, suggesting possible benefit from immune checkpoint inhibitors.

FGFR1 and FGFR4 oncogenicity depends on n-cadherin and their co-expression may predict FGFR-targeted therapy efficacy

BACKGROUND

Fibroblast growth factor receptor (FGFR)1 and FGFR4 have been associated with tumorigenesis in a variety of tumour types. As a therapeutic approach, their inhibition has been attempted in different types of malignancies, including lung cancer, and was initially focused on FGFR1-amplified tumours, though with limited success.

METHODS

In vitro and in vivo functional assessments of the oncogenic potential of downregulated/overexpressed genes in isogenic cell lines were performed, as well as inhibitor efficacy tests in vitro and in vivo in patient-derived xenografts (PDXs). mRNA was extracted from FFPE non-small cell lung cancer samples to determine the prognostic potential of the genes under study.

FINDINGS

We provide in vitro and in vivo evidence showing that expression of the adhesion molecule N-cadherin is key for the oncogenic role of FGFR1/4 in non-small cell lung cancer. According to this, assessment of the expression of genes in different lung cancer patient cohorts showed that FGFR1 or FGFR4 expression alone showed no prognostic potential, and that only co-expression of FGFR1 and/or FGFR4 with N-cadherin inferred a poorer outcome. Treatment of high-FGFR1 and/or FGFR4-expressing lung cancer cell lines and patient-derived xenografts with selective FGFR inhibitors showed high efficacy, but only in models with high FGFR1/4 and N-cadherin expression.

INTERPRETATION

Our data show that the determination of the expression of FGFR1 or FGFR4 alone is not sufficient to predict anti-FGFR therapy efficacy; complementary determination of N-cadherin expression may further optimise patient selection for this therapeutic strategy.