Search

Biliary tract cancers (BTCs) are rare and aggressive tumors that typically present at an advanced stage when surgical resection is no longer considered a therapeutic option. While gemcitabine and cisplatin have been the mainstay of treatment, unique chemotherapy combination strategies, targeted therapies, and immunotherapies have had some clinical efficacy and remain promising areas for clinical research. The use of molecular profiling of BTCs has facilitated the development and subsequent clinical application of novel targeted therapy compounds. Among the many genomic alterations identified in BTCs, molecular abnormalities in the fibroblast growth factor receptor (FGFR), isocitrate dehydrogenase (IDH), human epidermal growth factor receptor 2 (HER2), and BRAF have been successfully targeted therapeutically in clinical trials. Furthermore, the expanded use of new chemotherapy combinations, targeted therapies, and immunotherapies into alternate clinical settings such as in the neoadjuvant and adjuvant spaces is an area of active investigation. The management of BTCs is rapidly evolving. In this article, we review the emerging targets and therapies in BTC.

Disease recurrence is common following prostatectomy in patients with localised prostate cancer with high-risk features. Although androgen deprivation therapy increases the rates of organ-confined disease and negative surgical margins, there is no significant benefit on disease recurrence. Multiple lines of evidence suggest that (Fibroblast Growth Factor/Fibroblast Growth Factor Receptor) FGF/FGFR-signalling is important in supporting prostate epithelial cell survival in hostile conditions, including acute androgen deprivation. Given the recent availability of oral FGFR inhibitors, we investigated whether combination therapy could improve tumour response in the neo-adjuvant setting.We conducted an open label phase II study of the combination of erdafitinib (3 months) and androgen deprivation therapy (4 months) in men with localised prostate cancer with high-risk features prior to prostatectomy using a Simon's 2 stage design. The co-primary endpoints were safety and tolerability and pathological response in the prostatectomy specimen. The effect of treatment on residual tumours was explored by global transcriptional profiling with RNA-sequencing.Nine patients were enrolled in the first stage of the trial. The treatment combination was poorly tolerated. Erdafitinib treatment was discontinued early in six patients, three of whom also required dose interruptions/reductions. Androgen deprivation therapy for 4 months was completed in all patients. The most common adverse events were hyperphosphataemia, taste disturbance, dry mouth and nail changes. No patients achieved a complete pathological response, although patients who tolerated erdafitinib for longer had smaller residual tumours, associated with reduced transcriptional signatures of epithelial cell proliferation.Although there was a possible enhanced anti-tumour effect of androgen deprivation therapy in combination with erdafitnib in treatment naïve prostate cancer, the poor tolerability in this patient population prohibits the use of this combination in this setting.

Background: This study is part of a larger research effort to explore the molecular mechanism of hepatocellular carcinoma, reduce drug resistance and seek new targets. Objective: The objective of this study is to investigate the effect and mechanism of fibroblast growth factor receptor inhibitor AZD4547 on Sorafenib-resistant hepatoma cells. Methods: First, we constructed a Sorafenib-resistant hepatoma cell line Huh7R. Different groups of Huh7R cells were treated with Sorafenib, AZD4547, Sorafenib combined with AZD4547, and normal saline. The cell viability was detected by Cell Counting Kit-8. Then Fibroblast growth factor receptor and Toll-like receptor 4 were detected by Western blot, as well as the LC3 II/I, Beclin1, and P62. In addition, we used the autophagy inhibitor 3-methyladenine to identify the mechanism of AZD4547 combined with Sorafenib for inducing Sorafenib-resistant hepatoma cell death. Results: We find that AZD4547 combined with Sorafenib significantly inhibited the viability of Sorafenib-resistant hepatoma cell Huh7R. As for its mechanism, AZD4547 was able to inhibit fibroblast growth factor receptor activity, promote autophagy and regulate immunity. AZD4547 increased LC3 II/I, Beclin1, and Toll-like receptor 4 proteins, and decreased P62 protein level in Huh7R cells significantly when given in combination with sorafenib. Furthermore, 3-methyladenine inhibited autophagy and reversed the killing effect of the combination of AZD4547 and Sorafenib on Huh7R cells. Conclusion: The inhibition of fibroblast growth factor receptor activity by AZD4547 can significantly enhance autophagy and immune response, as well as promote the death of Sorafenib-resistant hepatoma cells.

Fibroblast growth factor receptor inhibitors (FGFRi) were introduced into clinical trials on several cancer types and found to be particularly efficacious on urothelial cancer and cholangiocarcinoma. Although many enrolled patients responded well in clinical trials, there were some patients who did not respond to FGFRi even though their tumors carried the genomic changes that met the enrollment criteria. As already established, fibroblast growth factor receptor (FGFR) and epidermal growth factor receptor (EGFR) share the downstream signaling pathway of MAPK activation. Accordingly, it is conceivable that targeted inhibition of FGFR alone could leave the MAPK signaling unaffected when the signaling through EGFR is relatively strong. To test this hypothesis, we calculated here the FGFR to EGFR mRNA ratio (F/E for short) of biliary tract and urothelial cancer cell lines utilized in preclinical studies. In six biliary tract cancer cell lines, two responsive lines had an F/E of 9.5 and 9.0, whereas the F/E of four nonresponsive lines was 0.1-1.8. In 22 urothelial cancer cell lines, four of the five responsive lines showed an F/E of 2.8-4.9 (median, 3.6), whereas the F/E range of 17 nonresponsive lines was 0.01-2.7 (median, 0.6) (p = 0.004). We further investigated our 47 patient-derived colorectal cancer-stem cell spheroid lines. The 18 responsive lines showed relatively high F/E (median, 16.4), whereas 29 nonresponsive lines had low F/E (median, 9.2) (p = 0.0006). These results suggest that F/E is another strong predictor of responses to FGFRi that is as useful as the current genomic criteria based solely on the FGFR genomic changes.

To summarize targeted therapies and immunotherapy as treatment for advanced/metastatic biliary tract cancers and discuss ongoing clinical trials.For the first time since gemcitabine-cisplatin was set as the standard of care in first-line advanced/metastatic biliary tract cancers in the ABC-02 trial, the combination of durvalumab and gemcitabine-cisplatin has demonstrated a statistically significant improvement of median overall survival in the TOPAZ-1 phase 3 trial. The ABC-06 trial showed a significant increase of median overall survival for FOLFOX and active symptom control compared with active symptom control alone in second-line regardless of molecular and genetic alterations. However, faced with a heterogeneous cancer, patient prognosis remains poor, leaving room for new, personalized, treatment options such as targeted therapies. Efficacy of fibroblast growth factor receptor (FGFR) tyrosine kinase inhibitors has been demonstrated in different phase 2 trials for previously treated intrahepatic cholangiocarcinomas harboring FGFR2 fusions. Ivosidenib increases significantly median progression-free survival in previously treated cholangiocarcinomas with isocitrate dehydrogenase-1 (IDH-1) mutation. Other targeted therapies are tested for tumors with HER2 amplifications/mutations, BRAFV600E mutations or KRASG12C mutations.In this review, we aim to follow the changes in the treatment of these tumors, moving from very few chemotherapy options to immunotherapy and targeted therapies in the context of molecular selection of biliary tract cancers subtypes.

AS an allosteric inhibitor of fibroblast growth factor receptors (FGFRs), SSR128129E (SSR) extensively inhibits the fibroblast growth factor (FGF) signaling. Given the metabolic importance of FGFs and the global epidemic of obesity, we explored the effect of SSR on fat metabolism.Three-week-old male mice were administered intragastrically with SSR (30 mg/kg/day) or PBS for 5 weeks. The effects of SSR on white and brown fat metabolism were investigated by respiratory metabolic monitoring, histological assessment and molecular analysis. Results indicated that SSR administration significantly reduced the body weight gain and the fat content of mice. SSR did not increase, but decreased the thermogenic capability of both brown and white fat. However, SSR markedly suppressed adipogenesis of adipose tissues. Further study demonstrated the involvement of ERK signaling in the action of SSR.SSR may be a promising drug candidate for the prevention of obesity via suppressing adipogenesis. However, the influence of SSR on thermogenesis in humans should be further investigated before its clinical application.

BACKGROUND: Fibroblast growth factor receptor (FGFR) signaling influenced tumour occurrence and development. Overexpression of FGFR had been observed in many types of cancers, including colon cancer. FGFR inhibitor is considered to be effective in treating colon cancer patients. METHODS: First, the kinase inhibition rate was determined. MTT, western blotting, colony formation, EdU and comet assays were performed to evaluate the anti-tumour effects of F1-7 in vitro. RNA-seq and bioinformatics analysis were used for further verification. Additionally, a xenograft model was generated to investigate the anti-tumour effect of F1-7. RESULTS: F1-7 can inhibit the proliferation of colon cancer cells in vitro. It could significantly inhibit FGFR phosphorylation and its downstream signaling pathway. Whole-genome RNA-seq analysis found that the changed genes were not only functionally focused on MAPK signaling pathway but also related to cell apoptosis and ferroptosis. Experimental evidence demonstrated that F1-7 can directly increase the level of cellular DNA damage. The occurrence of DNA damage led to cell cycle arrest and inhibition of cell metastasis and cell apoptosis. Mouse model experiments also confirmed that F1-7 could inhibit tumour growth by inhibiting the FGFR pathway. CONCLUSIONS: F1-7 exhibits anti-tumour activity by inhibiting the FGFR pathway. It could be a novel therapeutic agent for targeting colon cancer cells.

Fibroblast growth factor receptor (FGFR)-signaling in lung squamous cell carcinoma (LSCC) is associated with cancer aggressiveness and poor prognosis. Small GTPase RAB11A regulates the recycling of membrane proteins such as FGFR. This study evaluated the potential of RAB11A as a new therapeutic target for LSCC through its regulation of FGFR-signaling.Immunohistochemical analysis of 84 LSCC samples was performed to determine the correlation between RAB11A expression, clinicopathologic features, and prognosis. Alterations in FGFR-signaling were assessed in RAB11A-suppressed and RAB11A-overexpressed LSCC cells both in vitro and in vivo.The study identified RAB11A as a strong predictor of poor prognosis in the LSCC cohort. Cell proliferation and invasion were promoted and inhibited respectively in RAB11A-overexpressed and RAB11A -suppressed LSCC cells. In RAB11A-overexpressed and RAB11A-suppressed LSCC cells, FGFR-signaling was respectively up- and downregulated. The viability of the cells treated with nintedanib and lenvatinib was greater in RAB11A-overexpressing cells than in control cells. The in vivo tumor growth and micro-vessel density of RAB11A-overexpressing tumors were significantly higher than in the control cells.As a potentially valuable prognostic marker, RAB11A is a promising therapeutic target for LSCC. Evaluation of RAB11A may be useful for identification of LSCC in patients whose cancer is refractory to FGFR inhibitors.

Bladder cancer (BC) is a common malignancy of the urological system that still lacks effective treatment. It is frequently characterised by dysregulation of fibroblast growth factor receptor (FGFR) signalling. FGFR inhibitors have been proven as a promising treatment for BC in clinical settings. Besides the FGFR signalling, the therapeutic effects of FGFR inhibitors are often limited owing to various mechanisms, such as the activation of the Akt signalling pathway. Therefore, this study aimed to examine the synergistic effects of ipatasertib, a FGFR inhibitor, and erdafitinib, an Akt inhibitor, in BC cells. Ipatasertib and erdafitinib co-treatment synergistically inhibited cell proliferation and induced BC cell death. Mechanically, ipatasertib and erdafitinib induced the activation of Bax, an essential protein for cell death. Moreover, erdafitinib, which inhibited the Akt signalling pathway, is responsible for Bim upregulation, a condition critical to achieving the synergistic effects. Therefore, our data suggest that ipatasertib and erdafitinib co-treatment is a promising strategy for BC.

Head and neck squamous cell carcinoma (HNSCC) is commonly associated with tobacco and alcohol consumption that induce a "precancerous field," with phosphoinositide 3-kinase (PI3K) signaling being a common driver. However, the preclinical effectiveness of PI3K inhibitors has not necessarily translated to remarkable benefit in HNSCC patients. Thus, we sought to determine how precancerous keratinocytes influence HNSCC proliferation, cancer stem cell (CSC) maintenance, and response to PI3K inhibitors. We used the NOK keratinocyte cell line as a model of preneoplastic keratinocytes because it harbors two frequent genetic events in HNSCC, CDKN2A promoter methylation and TP53 mutation, but does not form tumors. NOK cell coculture or NOK cell-conditioned media promoted HNSCC proliferation, PI3K inhibitor resistance, and CSC phenotypes. SOMAscan-targeted proteomics determined the relative levels of1300 analytes in the media conditioned by NOK cells and HNSCC cells ± PI3K inhibitor. These results demonstrated that NOK cells release abundant levels of ligands that activate epidermal growth factor receptor (EGFR) and fibroblast growth factor receptor (FGFR), two receptor tyrosine kinases with oncogenic activity. Inhibition of EGFR, but not FGFR, blunted PI3K inhibitor resistance and CSC phenotypes induced by NOK cells. Our results demonstrate that precancerous keratinocytes can directly support neighboring HNSCC by activating EGFR. Importantly, PI3K inhibitor sensitivity was not necessarily a cancer cell-intrinsic property, and the tumor microenvironment impacts therapeutic response and supports CSCs. Additionally, combined inhibition of EGFR with PI3K inhibitor diminished EGFR activation induced by PI3K inhibitor and potently inhibited cancer cell proliferation and CSC maintenance.

INTRODUCTION: Fibroblast growth factor receptor (FGFR)-4/FGF19 pathway dysregulation is implicated in hepatobiliary and other solid tumors. INCB062079, an oral, selective, FGFR4 inhibitor, inhibits growth in FGF19/FGFR4-driven liver cancer models. METHODS: This was a two-part, phase I study (NCT03144661) in previously treated patients with advanced solid tumors. The primary objective was to determine safety, tolerability, and maximum tolerated dose (MTD), while secondary objectives included pharmacokinetics, pharmacodynamics (plasma FGF19; bile acid salts/7α-hydroxy-4-cholesten-3-one [C4] levels), and preliminary efficacy. In Part 1, patients received INCB062079 starting at 10 mg once daily, with 3 + 3 dose escalation. Part 2 (dose expansion) was not conducted because of study termination. RESULTS: Twenty-three patients were treated (hepatobiliary, n = 11; ovarian, n = 9; other, n = 3). Among six patients receiving 15 mg twice daily, two patients had dose-limiting toxicities (DLTs; grade 3 diarrhea, grade 3 transaminitis). Both had high pretreatment C4 concentrations, prompting a protocol amendment requiring pretreatment C4 concentrations

Magnesium (Mg) and some of its alloys are considered promising biodegradable metallic biomaterials for bone implant applications. The osteogenesis effect of Mg alloys is widely reported; however, the underlying mechanisms are still not clear. In this study, pure Mg, Mg-3Zn, and Mg-2Zn-1Mn were prepared, and their degradation behavior, biocompatibility, and osteogenesis effect were systematically assessed both in vitro and in vivo. Primary rat bone marrow-derived mesenchymal stem cells (BMSCs) were used to evaluate the biocompatibility of the prepared Mg alloys, and a rat femur fracture model was used to assess the stimulating effect of these alloys on bone-tissue formation. Mg-2Zn-1Mn showed higher corrosion resistance and more stable degradation behavior than pure Mg and Mg-3Zn. Extracts of the three materials showed significant stimulating effects on osteogenic differentiation of BMSCs along with non-cytotoxicity. Implantation of Mg-2Zn-1Mn wires into the femur of rats demonstrated superior histocompatibility, stable degradation, and notable promotion of osteogenesis without systemic toxicity. Moreover, the results of both in vitro and in vivo assessments demonstrated that bone morphogenetic proteins and fibroblast growth factor receptors are involved in the stimulating effect of Mg alloys. STATEMENT OF SIGNIFICANCE: This work reports the degradation behavior, biocompatibility, and osteogenic effect of pure Mg and Mg-3Zn and Mg-2Zn-1Mn alloys in both in vitro and in vivo conditions. Mg-2Zn-1Mn showed higher corrosion resistance and more stable degradation behavior than pure Mg and Mg-3Zn. The extracts of the three materials showed a significant stimulating effect on osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (BMSCs) along with non-cytotoxicity. Mg-2Zn-1Mn wires implanted into the femur of rats showed good histocompatibility, stable degradation, and notable promotion of osteogenesis without systemic toxicity. The results of the present study suggest that bone morphogenetic proteins (BMPs) and fibroblast growth factor receptors (FGFRs) are involved in the stimulating effect of Mg alloys on osteogenesis.

Fibroblast growth factor 8 (FGF-8), also known as androgen-induced growth factor (AIGF), is presumed to be a potent mitogenic cytokine that plays important roles in early embryonic development, brain formation and limb development. In the bone environment, FGF-8 produced or received by chondrocyte precursor cells binds to fibroblast growth factor receptor (FGFR), causing different levels of activation of downstream signalling pathways, such as phospholipase C gamma (PLCγ)/Ca

Cervical cancer is one of the most frequently diagnosed cancers in women worldwide. While cervical cancer is caused by human papillomavirus (HPV), not all females infected with HPV develop the disease, suggesting that other factors might facilitate its progression. Growing evidence supports the involvement of the fibroblast growth factor receptor (FGFR) axis in several cancers, including gynecological. However, for cervical cancer, the molecular mechanisms that underpin the disease remain poorly understood, including the role of FGFR signaling. The aim of this study was to investigate FGF(R) signaling in cervical cancer through bioinformatic analysis of cell line and patient data and through detailed expression profiling, manipulation of the FGFR axis, and downstream phenotypic analysis in cell lines (HeLa, SiHa, and CaSki). Expression (protein and mRNA) analysis demonstrated that FGFR1b/c, FGFR2b/c, FGFR4, FGF2, FGF4, and FGF7 were expressed in all three lines. Interestingly, FGFR1 and 2 localized to the nucleus, supporting that nuclear FGFRs could act as transcription factors. Importantly, 2D and 3D cell cultures demonstrated that FGFR activation can facilitate cell functions correlated with invasive disease. Collectively, this study supports an association between FGFR signaling and cervical cancer progression, laying the foundations for the development of therapeutic approaches targeting FGFR in this disease.

Background Exposure–response analyses were conducted to explore the relationship between selected efficacy and safety endpoints and serum phosphate (PO4) concentrations, a potential biomarker of efficacy and safety, in locally advanced or metastatic urothelial carcinoma patients with FGFR alterations treated with erdafitinib. Methods Data from two dosing regimens of erdafitinib in a phase 2 study (NCT02365597), 6 and 8-mg/day with provision for pharmacodynamically guided titration per serum PO4 levels, were analyzed using Cox proportional hazard or logistic regression models. Efficacy endpoints were overall survival (OS), progression-free survival (PFS), and objective response rate (ORR). Safety endpoints were adverse events typical for FGFR inhibitors. Results Exposure-efficacy analyses on 156 patients (6-mg = 68; 8-mg = 88) showed that patients with higher serum PO4 levels within the first 6 weeks showed better OS (hazard ratio 0.57 [95% CI 0.46–0.72] per mg/dL of PO4; p = 0.01), PFS (hazard ratio 0.80 [0.67–0.94] per mg/dL of PO4; p = 0.01), and ORR (odds ratio 1.38 [1.02–1.86] per mg/dL of PO4; p = 0.04). Exposure-safety analyses on 177 patients (6-mg = 78; 8-mg = 99) showed that the incidence of selected adverse events associated with on-target off-tumor effects significantly rose with higher PO4. Conclusions The exploratory relationship between serum PO4 levels and efficacy/safety outcomes supported the use of pharmacodynamically guided dose titration to optimize erdafitinib’s therapeutic benefit/risk ratio. Clinical trial registration number NCT02365597.

Alagille Syndrome (ALGS) is a congenital disorder caused by mutations in the Notch ligand gene JAGGED1, leading to neonatal loss of intrahepatic duct (IHD) cells and cholestasis. Cholestasis can resolve in certain patients with ALGS, suggesting regeneration of IHD cells. However, the mechanisms driving IHD cell regeneration following Jagged loss remains unclear. Here, we show that cholestasis due to developmental loss of IHD cells can be consistently phenocopied in zebrafish with compound jagged1b and jagged2b mutations or knockdown.Leveraging the transience of jagged knockdown in juvenile zebrafish, we find that resumption of Jagged expression leads to robust regeneration of IHD cells through a Notch-dependent mechanism. Combining multiple lineage tracing strategies with whole-liver three-dimensional imaging, we demonstrate that the extrahepatic duct (EHD) is the primary source of multipotent progenitors that contribute to the regeneration, but not to the development, of IHD cells. Hepatocyte-to-IHD cell transdifferentiation is possible but rarely detected. Progenitors in the EHD proliferate and migrate into the liver with Notch signaling loss and differentiate into IHD cells if Notch signaling increases. Tissue-specific mosaic analysis with an inducible dominant-negative Fgf receptor suggests that Fgf signaling from the surrounding mesenchymal cells maintains this extrahepatic niche by directly preventing premature differentiation and allocation of EHD progenitors to the liver. Indeed, transcriptional profiling and functional analysis of adult mouse EHD organoids uncover their distinct differentiation and proliferative potential relative to IHD organoids.Our data show that IHD cells regenerate upon resumption of Jagged/Notch signaling, from multipotent progenitors originating from an Fgf-dependent extrahepatic stem cell niche. We posit that if Jagged/Notch signaling is augmented, through normal stochastic variation, gene therapy, or a Notch agonist, regeneration of IHD cells in patients with ALGS may be enhanced.

Erdafitinib is the first fibroblast growth factor receptor inhibitor approved by the U.S. Food and Drug Administration in April 2019 for the treatment of locally advanced and unresectable or metastatic urothelial carcinoma. Central serous chorioretinopathy is a common ocular adverse effect requiring frequent monitoring with ophthalmic examination.This study aimed to increase awareness of erdafitinib-induced central serous chorioretinopathy, highlight erdafitinib dose management guidelines, and emphasize the importance of collaborating with oncologists to prevent adverse visual consequences.An 80-year-old patient with an advanced urothelial cancer with fibroblast growth factor receptor mutations developed central serous chorioretinopathy when he was treated with daily 8 mg of erdafitinib. The erdafitinib-induced central serous chorioretinopathy resolved completely after the discontinuation of erdafitinib. He was then treated with daily 6 mg of erdafitinib and again developed central serous chorioretinopathy, which resolved completely upon discontinuation of the medication. The patient then decided to stop treatment with erdafitinib.Erdafitinib, a potent tyrosine kinase receptor inhibitor of fibroblast growth factor receptors 1 to 4, demonstrates antitumor activity in advanced urothelial carcinoma with fibroblast growth factor receptor mutations with a response rate of approximately 40%. However, central serous chorioretinopathy develops in 25% of patients treated with a daily 8-mg dose of erdafitinib. Although most mild to moderate erdafitinib-induced central serous chorioretinopathies resolve with dose interruption or reduction, occasionally discontinuation of the medication is necessary. Therefore, careful coordination with oncologists is important to assess the impact of erdafitinib on vision, quality of life, and survival prognosis.

Development of chemoresistance is one of the major obstacles to the treatment of head and neck squamous cell carcinoma (HNSCC). The PI3K/Akt pathway, involved in drug resistance, has been found to be overactivated in > 90% of HNSCCs. Aberrant activation of the FGF receptors (FGFRs) has been reported to cause overactivation of the PI3K/Akt pathway and to be associated with the maintenance of stem cell features, which is controlled via SOX2 expression. In this study, we aimed at investigating the potential of using AZD4547, an orally bioavailable FGFR inhibitor, to overcome taxol-resistance by targeting the FGFR/Akt/SOX2 axis in HNSCC. We initially evaluated FGFR2 and SOX2 expression using in silico tools. We analyzed the FGFR/Akt/SOX2 axis in normal/tumor tissue pairs and in recombinant FGF2 treated HNSCC cells. Next, we explored the effects of AZD4547 alone and in combination with taxol on the proliferation, migration and colony forming capacities of parental/taxol-resistant cells using in vitro models. We found that the p-FGFR, p-AKT, p-GSK-3β and SOX2 expression levels were higher in tumor tissues than in its corresponding normal tissues, and that AZD4547 effectively suppressed the expression of FGFR and its downstream targets in recombinant FGF2 treated HNSCC cells. We also found that AZD4547 diminished the viability, migration and colony forming capacity of HNSCC cells, and that co-treatment with taxol potentiated the impact of taxol on these cells. Finally, we found that AZD4547 inhibited the overexpressed FGFR/Akt/SOX2 axis and profoundly suppressed cancer-related phenotypes in taxol-resistant HNSCC cells. From our data we conclude that AZD4547 may increase the impact of taxol during HNSCC treatment. We suggest AZD4547 as a therapeutic agent to overcome taxol-resistance.

How cancer cells adapt to evade the therapeutic effects of drugs targeting oncogenic drivers is poorly understood. Here we report an epigenetic mechanism leading to the adaptive resistance of triple-negative breast cancer (TNBC) to fibroblast growth factor receptor (FGFR) inhibitors. Prolonged FGFR inhibition suppresses the function of BRG1-dependent chromatin remodelling, leading to an epigenetic state that derepresses YAP-associated enhancers. These chromatin changes induce the expression of several amino acid transporters, resulting in increased intracellular levels of specific amino acids that reactivate mTORC1. Consistent with this mechanism, addition of mTORC1 or YAP inhibitors to FGFR blockade synergistically attenuated the growth of TNBC patient-derived xenograft models. Collectively, these findings reveal a feedback loop involving an epigenetic state transition and metabolic reprogramming that leads to adaptive therapeutic resistance and provides potential therapeutic strategies to overcome this mechanism of resistance. Li et al. define an adaptive resistance mechanism against FGFR inhibitor treatment in breast cancer attributed to loss of BRG1 chromatin recruitment, reactivation of YAP-dependent enhancers and upregulation of amino acid-induced mTORC1 activity.

Background Angiogenesis has an important role in thymic epithelial tumors (TETs). Regorafenib inhibits vascular endothelial growth factor receptors (VEGFRs), platelet-derived growth factor receptor β (PDGFR-β), and fibroblast growth factor receptors (FGFRs). This study explored the activity of regorafenib as monotherapy in patients with advanced or recurrent B2-B3 thymoma (T) and thymic carcinoma (TC) previously treated with platinum-containing chemotherapy. Methods A Fleming single-arm, single-stage, phase 2 trial to evaluate the activity of regorafenib (160 mg once a day by mouth for 3 weeks on/1 week off) was planned. The study was designed to reject the null hypothesis of an 8-week progression-free survival (PFS) rate ≤25% with a type I error of 0.10 and a statistical power of 80% at the alternative hypothesis of an 8-week PFS rate of ≥50% (≥8 of 19 evaluable patients progression-free at 2 months). Results From June 2016 to November 2017, 19 patients were enrolled (11T/8TC). We observed partial response (PR) in 1 patient (1T) (5.3%), stable disease (SD) in 14 patients (9T/5TC) (73.7%), and progressive disease in 2 patients (1T/1TC) (10.5%), with a disease control rate of 78.9%. According to Choi-criteria, 13 patients (68.4%) achieved PR, and 2 patients SD (10.5%). The median PFS was 9.6 months whereas median overall survival was 33.8 months. The 8-week PFS rate was 78.9% (15 of 19 patients). Grade 3-4 treatment-related adverse events were observed in 10 patients (52.6%). Conclusions The primary end point of this study was reached. The high rate of PR (Choi-criteria) suggests antitumor activity of regorafenib in TETs. On the basis of survival outcomes, the efficacy of regorafenib should be further evaluated in larger studies.

Osteoarthritis (OA) is a major health problem worldwide that affects the joints and causes severe disability. It is characterized by pain and low-grade inflammation. However, the exact pathogenesis remains unknown and the therapeutic options are limited. In OA articular chondrocytes undergo a phenotypic transition becoming hypertrophic, which leads to cartilage damage, aggravating the disease. Therefore, a therapeutic agent inhibiting hypertrophy would be a promising disease-modifying drug. The therapeutic use of tyrosine kinase inhibitors has been mainly focused on oncology, but the Food and Drug Administration (FDA) approval of the Janus kinase inhibitor Tofacitinib in Rheumatoid Arthritis has broadened the applicability of these compounds to other diseases. Interestingly, tyrosine kinases have been associated with chondrocyte hypertrophy. In this review, we discuss the experimental evidence that implicates specific tyrosine kinases in signaling pathways promoting chondrocyte hypertrophy, highlighting their potential as therapeutic targets for OA.

Fibroblast growth factor receptors (FGFRs) play key roles in promoting cancer cell proliferation, differentiation, and migration. However, acquired resistance to FGFR inhibitors has become an emerging challenge in long-term cancer therapies, especially for hepatocellular carcinoma (HCC). Gatekeeper (GK) mutations are the main mechanism of resistance. Herein, we describe the discovery of a series of reversible FGFR inhibitors, particularly for GK mutations with the 2-amino-7-sulfonyl-7

BackgroundThe emergence of immune checkpoint inhibitors (ICIs) has significantly improved the clinical outcomes of patients with metastatic melanoma. However, survival benefits are only observed in a subset of patients. The fibroblast growth factor receptor (FGFR) family genes are frequently mutated in melanoma, yet their impacts on the efficacy of ICIs remain unclear. Our study aimed to explore the association of FGFR mutations with ICIs efficacy in metastatic melanoma.MethodsThe Cancer Genome Atlas (TCGA) data (PanCancer Atlas, skin cutaneous melanoma (SKCM), n = 448) in cBioPortal were collected as a TCGA cohort to investigate the association between FGFR mutations and prognosis of melanoma patients. To explore the impact of FGFR mutations on the efficacy of ICIs in melanoma, clinical and tumor whole-exome sequencing (WES) data of four ICI-treated studies from cBioPortal were consolidated as an ICIs-treated cohort. Moreover, the relationship between FGFR mutations and immunogenicity (tumor mutation burden (TMB), neo-antigen load (NAL), mismatch repair (MMR)-related genes and DNA damage repair (DDR)-related genes) of melanoma was evaluated utilizing data from the ICIs-treated cohort. The influence of FGFR mutations on the tumor immune microenvironment (TIME) of melanoma was also analyzed using the TCGA cohort.ResultsIn the TCGA cohort, survival in melanoma patients with or without FGFR mutations was nearly equivalent. In the ICIs-treated cohort, patients with FGFR mutations had better survival than those without (median overall survival: 60.00 vs. 31.00 months; hazard ratio: 0.58, 95% CI: 0.42-0.80; P = 0.0051). Besides, the objective response rate was higher for patients harboring FGFR mutations (55.56%) compared to wild-type patients (22.40%) (P = 0.0076). Mechanistically, it was revealed that FGFR mutations correlated with increased immunogenicity (e.g., TMB, NAL, MMR-related gene mutations and DDR-related gene mutations). Meanwhile, FGFR mutant melanoma tended to exhibit an enhanced antitumor TIME compared with its wild-type counterparts.ConclusionsOur study demonstrated that FGFR mutations is a promising biomarker in stratifying patients with advanced melanoma who might benefit from ICIs therapy.

Background The defects and imbalance in lung repair and structural maintenance contribute to the pathogenesis of chronic obstructive pulmonary diseases (COPD), yet the molecular mechanisms that regulate lung repair process are so far incompletely understood. We hypothesized that cigarette smoking causes glycocalyx impairment and endothelial apoptosis in COPD, which could be repaired by the stimulation of fibroblast growth factor 10 (FGF10)/FGF receptor 1 (FGFR1) signaling. Methods We used immunostaining (immunohistochemical [IHC] and immunofluorescence [IF]) and enzyme-linked immunosorbent assay (ELISA) to detect the levels of glycocalyx components and endothelial apoptosis in animal models and in patients with COPD. We used the murine emphysema model and in vitro studies to determine the protective and reparative role of FGF10/FGFR1. Results Exposure to cigarette smoke caused endothelial glycocalyx impairment and emphysematous changes in murine models and human specimens. Pretreatment of FGF10 attenuated the development of emphysema and the shedding of glycocalyx components induced by CSE in vivo. However, FGF10 did not attenuate the emphysema induced by endothelial-specific killing peptide CGSPGWVRC-GG-D(KLAKLAK)2. Mechanistically, FGF10 alleviated smoke-induced endothelial apoptosis and glycocalyx repair through FGFR1/ERK/SOX9/HS6ST1 signaling in vitro. FGF10 was shown to repair pulmonary glycocalyx injury and endothelial apoptosis, and attenuate smoke-induced COPD through FGFR1 signaling. Conclusions Our results suggest that FGF10 may serve as a potential therapeutic strategy against COPD via endothelial repair and glycocalyx reconstitution.

Excess sebum (seborrhea) results in oily skin and is associated with large pore size and acne. Studies in healthy, seborrheic volunteers have reported that intradermal injection of commercial preparations of botulinum neurotoxin type A (BoNT/A) (onabotulinumtoxinA, abobotulinumtoxinA, and incobotulinumtoxinA) reduced sebum production, and thus, skin oiliness and pore size. The mechanism for these effects has not been fully elucidated; however, several theories involving direct or indirect effects of BoNT/A on neuronal and/or dermal cells (e.g., sebocytes) have been proposed. In the present study, we evaluated the direct effect of native research grade BoNT/A complex, a commercial preparation of BoNT/A (onabotA), and BoNT/A variants on sebocyte lipogenesis using an in vitro sebocyte cell model. We show that picomolar concentrations of BoNT/A (BoNT/A complex: half maximal effective concentration [EC50] = 24 pM; BoNT/A 150 kDa: EC50 = 34 pM) modulate sebocyte lipogenesis and reduce oleic acid-induced sebocyte differentiation, lipogenesis, and holocrine-like secretion. Comparative studies with the binding domain of BoNT/A, which lacks enzymatic activity, show that this effect is independent of the enzymatic activity of BoNT/A and likely occurs via sebocyte cell surface receptors (e.g., fibroblast growth factor receptors). Overall, these results shed light on the potential mechanism of action and rationale for use of BoNT/A for treatment of sebum-related conditions.

Fibroblast growth factor receptors (FGFRs) are a subfamily of receptor tyrosine kinases and central players in health and disease. Following ligand binding and the formation of homo- and heteromeric complexes, FGFRs initiate a cellular response. Challenges in studying FGFR activation are inner-subfamily interactions and a complex heterogeneity of these in the cell membrane, which demand for observation techniques that can resolve individual protein complexes and that are compatible with endogenous protein levels. Here, we established an imaging and analysis pipeline for multiplexed single-molecule localization microscopy (SMLM) of the FGFR network at the plasma membrane. Using DNA-labeled primary antibodies, we visualize all four FGFRs in the same cell with near-molecular spatial resolution. From the super-resolution imaging data, we extract information on FGFR density, spatial distribution, and inner-subfamily colocalization. Our approach is straightforward and easily adaptable to other multiplexed SMLM data of membrane proteins.

Infigratinib (INF) is a promising selective inhibitor of fibroblast growth factor receptors 1-3 that has recently been accorded both orphan drug designation and priority review status by the U.S Food and Drug Administration for the treatment of advanced cholangiocarcinoma. Its propensity to undergo bioactivation to electrophilic species was recently expounded upon. However, other than causing aberrant idiosyncratic toxicities, these reactive intermediates may elicit mechanism-based inactivation (MBI) of cytochrome P450 enzymes (CYP450). In this study, we investigated the interactions between INF and the most abundant hepatic cytochrome P450 3A4 (CYP3A4). Our findings revealed that apart from being a potent noncompetitive reversible inhibitor of CYP3A4, INF inactivated CYP3A4 in a time-, concentration- and NADPH-dependent manner with KI, kinact and partition ratio of 2.45 µM, 0.053 min-1 and 41 respectively when rivaroxaban was employed as the probe substrate. Co-incubation with testosterone (alternative CYP3A substrate) or ketoconazole (direct CYP3A inhibitor) attenuated the rate of inactivation whereas the inclusion of glutathione and catalase did not confer such protection. The lack of enzyme activity recovery following dialysis for 4 hours and oxidation with potassium ferricyanide, coupled with the absence of the characteristic Soret peak signature collectively substantiated that inactivation of CYP3A4 by INF was not mediated by the formation of quasi-irreversible metabolite-intermediate complexes but rather through irreversible covalent adduction to the prosthetic heme and/or apoprotein. Finally, glutathione trapping and high-resolution mass spectrometry experimental results unravelled two plausible bioactivation mechanisms of INF arising from the generation of a p-benzoquinone diimine and epoxide reactive intermediate. Significance Statement The potential of infigratinib (INF) to cause mechanism-based inactivation (MBI) of CYP3A4 was unknown. We report the reversible noncompetitive inhibition and irreversible covalent MBI of CYP3A4 by INF and proposed two potential bioactivation pathways implicating p-benzoquinone diimine and epoxide reactive intermediates. Findings from this study lay the groundwork for future investigation of clinically-relevant drug-drug interactions between INF and concomitant substrates of CYP3A4.

Infigratinib (TRUSELTIQTM), a fibroblast growth factor receptor (FGFR)-specific tyrosine kinase inhibitor, is being co-developed by QED Therapeutics and Helsinn for the treatment of cholangiocarcinoma, urothelial carcinoma and other FGFR-driven conditions. Infigratinib was recently approved in the USA for the treatment of previously treated, unresectable locally advanced or metastatic cholangiocarcinoma with a FGFR2 fusion or other rearrangement as detected by a test approved by the US Food and Drug Administration. This article summarizes the milestones in the development of infigratinib leading to this first approval for advanced cholangiocarcinoma. Supplementary Information The online version contains supplementary material available at 10.1007/s40265-021-01567-1.

Since phosphorus is a component of hydroxyapatite, its prolonged deprivation affects bone mineralization. Fibroblast growth factor 23 (FGF23) is essential for maintaining phosphate homeostasis and is mainly produced by osteocytes. FGF23 increases the excretion of inorganic phosphate (Pi) and decreases the production of 1,25-dihydroxyvitamin D in the kidneys. Osteocytes are cells of osteoblastic lineage that have undergone terminal differentiation and become embedded in mineralized bone matrix. Osteocytes express FGF23 and other multiple genes responsible for hereditary hypophosphatemic rickets, which include phosphate-regulating gene homologous to endopeptidase on X chromosome (PHEX), dentin matrix protein 1 (DMP1), and family with sequence similarity 20, member C (FAM20C). Since inactivating mutations in PHEX, DMP1, and FAM20C boost the production of FGF23, these molecules might be considered as local negative regulators of FGF23. Mouse studies have suggested that enhanced FGF receptor (FGFR) signaling is involved in the overproduction of FGF23 in PHEX-deficient X-linked hypophosphatemic rickets (XLH) and DMP1-deficient autosomal recessive hypophosphatemic rickets type 1. Since FGFR is involved in the transduction of signals evoked by extracellular Pi, Pi sensing in osteocytes may be abnormal in these diseases. Serum levels of sclerostin, an inhibitor Wnt/β-catenin signaling secreted by osteocytes, are increased in XLH patients, and mouse studies have suggested the potential of inhibiting sclerostin as a new therapeutic option for the disease. The elucidation of complex abnormalities in the osteocytes of FGF23-related hypophosphatemic diseases will provide a more detailed understanding of their pathogenesis and more effective treatments.