A novel FGFR1 inhibitor CYY292 suppresses tumor progression, invasion, and metastasis of glioblastoma by inhibiting the Akt/GSK3β/snail signaling axis

Glioblastoma (GBM) is a malignant brain tumor that grows quickly, spreads widely, and is resistant to treatment. Fibroblast growth factor receptor (FGFR)1 is a receptor tyrosine kinase that regulates cellular processes, including proliferation, survival, migration, and differentiation. FGFR1 was predominantly expressed in GBM tissues, and FGFR1 expression was negatively correlated with overall survival. We rationally designed a novel small molecule CYY292, which exhibited a strong affinity for the FGFR1 protein in GBM cell lines in vitro. CYY292 also exerted an effect on the conserved Ser777 residue of FGFR1. CYY292 dose-dependently inhibited cell proliferation, epithelial-mesenchymal transition, stemness, invasion, and migration in vitro by specifically targeting the FGFR1/AKT/Snail pathways in GBM cells, and this effect was prevented by pharmacological inhibitors and critical gene knockdown. In vivo experiments revealed that CYY292 inhibited U87MG tumor growth more effectively than AZD4547. CYY292 also efficiently reduced GBM cell proliferation and increased survival in orthotopic GBM models. This study further elucidates the function of FGFR1 in the GBM and reveals the effect of CYY292, which targets FGFR1, on downstream signaling pathways directly reducing GBM cell growth, invasion, and metastasis and thus impairing the recruitment, activation, and function of immune cells.

ATF4 renders human T-cell acute lymphoblastic leukemia cell resistance to FGFR1 inhibitors through amino acid metabolic reprogramming

Abnormalities of FGFR1 have been reported in multiple malignancies, suggesting FGFR1 as a potential target for precision treatment, but drug resistance remains a formidable obstacle. In this study, we explored whether FGFR1 acted a therapeutic target in human T-cell acute lymphoblastic leukemia (T-ALL) and the molecular mechanisms underlying T-ALL cell resistance to FGFR1 inhibitors. We showed that FGFR1 was significantly upregulated in human T-ALL and inversely correlated with the prognosis of patients. Knockdown of FGFR1 suppressed T-ALL growth and progression both in vitro and in vivo. However, the T-ALL cells were resistant to FGFR1 inhibitors AZD4547 and PD-166866 even though FGFR1 signaling was specifically inhibited in the early stage. Mechanistically, we found that FGFR1 inhibitors markedly increased the expression of ATF4, which was a major initiator for T-ALL resistance to FGFR1 inhibitors. We further revealed that FGFR1 inhibitors induced expression of ATF4 through enhancing chromatin accessibility combined with translational activation via the GCN2-eIF2α pathway. Subsequently, ATF4 remodeled the amino acid metabolism by stimulating the expression of multiple metabolic genes ASNS, ASS1, PHGDH and SLC1A5, maintaining the activation of mTORC1, which contributed to the drug resistance in T-ALL cells. Targeting FGFR1 and mTOR exhibited synergistically anti-leukemic efficacy. These results reveal that FGFR1 is a potential therapeutic target in human T-ALL, and ATF4-mediated amino acid metabolic reprogramming contributes to the FGFR1 inhibitor resistance. Synergistically inhibiting FGFR1 and mTOR can overcome this obstacle in T-ALL therapy.

Design, synthesis and biological evaluation of novel 1H-1,2,4-triazole, benzothiazole and indazole-based derivatives as potent FGFR1 inhibitors viafragment-based virtual screening

Fibroblast growth-factor receptor (FGFR) is a potential target for cancer therapy. We designed three novel series of FGFR1 inhibitors bearing indazole, benzothiazole, and 1H-1,2,4-triazole scaffold via fragment-based virtual screening. All the newly synthesised compounds were evaluated in vitro for their inhibitory activities against FGFR1. Compound 9d bearing an indazole scaffold was first identified as a hit compound, with excellent kinase inhibitory activity (IC₅₀ = 15.0 nM) and modest anti-proliferative activity (IC₅₀ = 785.8 nM). Through two rounds of optimisation, the indazole derivative 9 u stood out as the most potent FGFR1 inhibitors with the best enzyme inhibitory activity (IC₅₀ = 3.3 nM) and cellular activity (IC₅₀ = 468.2 nM). Moreover, 9 u also exhibited good kinase selectivity. In addition, molecular docking study was performed to investigate the binding mode between target compounds and FGFR1.

The discovery of potent and stable short peptide FGFR1 antagonist for cancer therapy

Fibroblast growth factor receptor 1 (FGFR1) is one of the attractive pharmaceutical targets for cancer therapy. The FGFR1 targeting antagonist peptides, especially of the short peptides harbouring only coding amino acid might highlights promising aspects for their higher affinity, specificity and lower adverse reactions. However, most of peptides inhibitors remain in preclinical research, likely associating with their instability and short half-life. In this study, we found a stable short peptide inhibitor P48 and speculated that its stability might be related to its non-linear spatial structure. In addition, P48 could target the extracellular immunoglobulin domain of FGFR1, and effectively block the particular signaling pathways of FGFR1, which lead to the inhibition of cancer proliferation, invasion in vitro and restraint of tumor growth in vivo. Together, this study provided a promising FGFR1 inhibitor with the potential to be developed as an antitumor drug.

C11, a novel fibroblast growth factor receptor 1 (FGFR1) inhibitor, suppresses breast cancer metastasis and angiogenesis

The fibroblast growth factor receptors (FGFRs) are increasingly considered attractive targets for therapeutic cancer intervention due to their roles in tumor metastasis and angiogenesis. Here, we identified a new selective FGFR inhibitor, C11, and assessed its antitumor activities. C11 was a selective FGFR1 inhibitor with an IC₅₀ of 19 nM among a panel of 20 tyrosine kinases. C11 inhibited cell proliferation in various tumors, particularly bladder cancer and breast cancer. C11 also inhibited breast cancer MDA-MB-231 cell migration and invasion via suppression of FGFR1 phosphorylation and its downstream signaling pathway. Suppression of matrix metalloproteinases 2/9 (MMP2/9) was associated with the anti-motility activity of C11. Furthermore, the anti-angiogenesis activity of C11 was verified in endothelial cells and chicken chorioallantoic membranes (CAMs). C11 inhibited the migration and tube formation of HMEC-1 endothelial cells and inhibited angiogenesis in a CAM assay. In sum, C11 is a novel selective FGFR1 inhibitor that exhibits potent activity against breast cancer metastasis and angiogenesis.

Combination effects of arsenic trioxide and fibroblast growth factor receptor inhibitor in squamous cell lung carcinoma

OBJECTIVES

Lung cancer remains the top cancer killer worldwide, with squamous cell carcinoma (SCC) as the second commonest histologic subtype. Arsenic trioxide (ATO) was previously shown to suppress growth of lung cancer. Fibroblast growth factor receptor (FGFR) amplification was recently demonstrated in lung SCC, with specific FGFR inhibitor (e.g. PD173074) developed as a potential targeted therapy. Therefore the combination effects of ATO and PD173074 in SCC was studied.

MATERIALS AND METHODS

The combination of ATO/PD173074 was studied in a proof-of-principle model using a lung SCC cell line with FGFR1 overexpression: SK-MES-1. The effects of ATO and/or PD173074 on cell viability and protein expression were studied by MTT assay and Western blot respectively. Cell cycle analysis, phosphatidylserine externalization and mitochondrial membrane depolarization were monitored by flow cytometry. FGFR1 knockdown was performed with siRNAs. Proteasome inhibitor (MG-132) was used to study the degradation mechanism. In vivo effect of ATO and/or PD173074 was investigated using a nude mice xenograft model.

RESULTS

Combined ATO/PD173074 reduced cell viability along with increased sub-G1 population, phosphatidylserine externalization and mitochondrial membrane depolarization more significantly than single treatments. Downregulation of FGFR1, p-Akt, Akt, p-Src, Src, p-c-Raf, c-Raf, Erk and survivin as well as upregulation of p-Erk and cleaved PARP were observed upon ATO and/or PD treatment. MG-132 partially reversed the degradation of Akt, Src, c-Raf and Erk induced by ATO/PD, suggestive of ubiquitin-independent proteasome-dependent degradation. However, the mechanism of FGFR1 downregulation remained unknown. Downregulation of FGFR1, Akt, Src, c-Raf and Erk as well as cleaved PARP elevation induced by ATO and/or PD were confirmed in vivo.

CONCLUSION

Massive protein degradation (FGFR1, Akt, Src, c-Raf and Erk) was induced by ATO and/or PD173074 treatment mainly mediated by activation of proteasomal degradation in SCC cell line SK-MES-1 in vitro and in vivo.

Design, synthesis and biological evaluation of naphthostyril derivatives as novel protein kinase FGFR1 inhibitors

New class of FGFR1 kinase inhibitors with naphthostyril heterocycle has been identified. A series of N-phenylnaphthostyril-1-sulfonamides has been synthesized and tested in vitro. It was revealed that the most active compound N-(4-hydroxyphenyl)naphthostyril-1-sulfonamide inhibited FGFR1 with IC50 of 2 µM. In our preliminary studies, N-phenylnaphthostyril-1-sulfonamides demonstrated selectivity of FGFR1 inhibition and antiproliferative activity on cancer cell line. N-phenylnaphthostyril-1-sulfonamides have a good potential for further development as anticancer agents.