Inhibition of both focal adhesion kinase and fibroblast growth factor receptor 2 pathways induces anti-tumor and anti-angiogenic activities

Design, synthesis and biological evaluation of 4-arylamino-pyrimidine derivatives as focal adhesion kinase inhibitors

A novel series of 4-arylamino-pyrimidine derivatives were designed and synthesized as focal adhesion kinase (FAK) inhibitors under the strategy of structure-based drug design. Most compounds performed excellent anti-proliferative activity against U87-MG cells. Especially, compounds 8d and 9b revealed the highest activity with IC50 values of 0.975 μM and 1.033 μM, which was much potent than the positive control TAE-226 (IC50 = 2.659 μM). On the other hand, the total 27 compounds exhibited low inhibition against human normal 2BS cells. Moreover, compounds 8d and 9b showed outstanding activity against FAK with IC50 values of 0.2438 nM and 0.2691 nM, which was very close to TAE-226 (IC50 = 0.1390 nM). Further studies proved that compounds 8d and 9b could induce U87-MG cell early apoptosis and arrest the cell at G2/M phase. The action mechanism indicated that they could significantly inhibit U87-MG cell clone formation, cell migration, and FAK phosphorylation. Molecular docking and molecular dynamics simulation investigations suggested that compounds 8d and 9b could firmly occupy the ATP binding site of FAK. These findings supported the further researches of compounds 8d and 9b as FAK inhibitors for antitumor drug discovery.

The Development of FAK Inhibitors: A Five-Year Update

Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase over-expressed in different solid cancers. In recent years, FAK has been recognized as a new target for the development of antitumor agents, useful to contrast tumor development and metastasis formation. To date, studies on the role of FAK and FAK inhibitors are of great interest for both pharmaceutical companies and academia. This review is focused on compounds able to block FAK with different potencies and with different mechanisms of action, that have appeared in the literature since 2017. Furthermore, new emerging PROTAC molecules have appeared in the literature. This summary could improve knowledge of new FAK inhibitors and provide information for future investigations, in particular, from a medicinal chemistry point of view.

Design, synthesis, and biological evaluation of novel covalent inhibitors targeting focal adhesion kinase

Forty-one new focal adhesion kinase (FAK) covalent inhibitors were designed and synthesized based on FAK inhibitor TAE226. Compound 11w displayed the highest inhibition of FAK with an IC₅₀ value of 35 nM and exhibited potent anticancer activity against Hela, HCT116 and MDA-MB-231 cell lines with IC₅₀ values of 0.41, 0.01 and 0.11 μM respectively, compared to TAE226 (2.68, 0.64 and 4.19 μM respectively). 11w also inhibited the clone formation and migration of HCT-116 cells and stimulated cell cycle arrest in the G₂/M phase, inducing tumor cell apoptosis. Compound 11w formed a covalent bond with the Cys427 residue of FAK in a docking model, inhibiting the autophosphorylation of FAK and downstream proteins in a dose-dependent manner. Moreover, 11w showed adequate oral bioavailability of 21.02%. A 74.20% inhibition of tumor growth in the HCT116 xenograft model was also observed. These data indicate that 11w is a promising covalent inhibitor of FAK.

Focal adhesion kinase inhibitors in the treatment of solid tumors: Preclinical and clinical evidence

Focal Adhesion Kinase (FAK) is a 125-kDa cytoplasmic protein kinase that is implicated in several cellular functions. This protein is an attractive molecular target for cancer therapy because a wide variety of studies have demonstrated associations between the activation or elevated expression of FAK and tumor progression, invasion, and drug resistance in malignant tumors. Here, we review the strategies used to inhibit FAK activity in solid tumors. We also include an overview of the preclinical (in vitro and in vivo) and clinical studies on FAK inhibitors.

FAK inhibitors as promising anticancer targets: present and future directions

FAK, a nonreceptor tyrosine kinase, has been recognized as a novel target class for the development of targeted anticancer agents. Overexpression of FAK is a common occurrence in several solid tumors, in which the kinase has been implicated in promoting metastases. Consequently, designing and developing potent FAK inhibitors is becoming an attractive goal, and FAK inhibitors are being recognized as a promising tool in our armamentarium for treating diverse cancers. This review comprehensively summarizes the different classes of synthetically derived compounds that have been reported as potent FAK inhibitors in the last three decades. Finally, the future of FAK-targeting smart drugs that are designed to slow down the emergence of drug resistance is discussed.

New Insights on Fak and Fak Inhibitors

BACKGROUND

Focal adhesion kinase (Fak) is a cytoplasmic protein tyrosine kinase overexpressed and activated in different solid cancers; it has shown an important role in metastasis formation, cell migration, invasion and angiogenesis and consequently it has been proposed as a potential target in cancer therapy, particularly in a metastatic phase. In recent years, different investigations have highlighted the importance of new Fak inhibitors as potential anti-cancer drugs, but other studies evidenced its role in different pathologies related to the cardiac function or viral infection.

METHODS

An extensive bibliographic research (104 references) has been done concerning the structure of Fak, its importance in tumor development, but also in other pathologies currently under study. The compounds currently subjected to clinical studies were therefore treated using the appropriate databases. Finally, the main chemical scaffolds currently under preclinical investigation were analyzed, focusing on their molecular structures and on the activity structure relationships (SAR).

RESULTS

At the moment, only a few reversible ATP-competitive inhibitors are under investigation in pre-clinical studies and clinical trials. Other compounds, with different chemical scaffolds, are investigated to obtain more active and selective Fak inhibitors. This mini-review is a summary of different Fak functions in cancer and other pathologies; the compounds today in clinical trials and the recent chemical scaffolds (also included in patents) giving the most interesting results are investigated. In addition, PROTAC molecules are reported.

CONCLUSION

All reported results evidenced that additional studies are necessary to design and synthesize new selective and more active compounds, although promising information has been obtained from associations between Fak inhibitors and other different anti- cancer drugs. In addition, the other important roles evidenced, both at the nuclear level and in non-cancerous cells, make this protein an increasingly important target in pharmaceutical chemistry.

The FAK inhibitor BI 853520 inhibits spheroid formation and orthotopic tumor growth in malignant pleural mesothelioma

No tyrosine kinase inhibitors are approved for malignant pleural mesothelioma (MPM). Preclinical studies identified focal adhesion kinase (FAK) as a target in MPM. Accordingly, we assessed the novel, highly selective FAK inhibitor (BI 853520) in 2D and 3D cultures and in vivo. IC50 values were measured by adherent cell viability assay. Cell migration and 3D growth were quantified by video microscopy and spheroid formation, respectively. Phosphorylation of FAK, Akt, S6, and Erk was measured by immunoblot. The mRNA expression of the putative tumor stem cell markers SOX2, Nanog, CD44, ALDH1, c-myc, and Oct4 was analyzed by qPCR. Cell proliferation, apoptosis, and tumor tissue microvessel density (MVD) were investigated in orthotopic MPM xenografts. In all 12 MPM cell lines, IC50 exceeded 5 μM and loss of NF2 did not correlate with sensitivity. No synergism was found with cisplatin in adherent cells. BI 853520 decreased migration in 3 out of 4 cell lines. FAK phosphorylation was reduced upon treatment but activation of Erk, Akt, or S6 remained unaffected. Nevertheless, BI 853520 inhibited spheroid growth and significantly reduced tumor weight, cell proliferation, and MVD in vivo. BI 853520 has limited effect in adherent cultures but demonstrates potent activity in spheroids and in orthotopic tumors in vivo. Based on our findings, further studies are warranted to explore the clinical utility of BI 853520 in human MPM. KEY MESSAGES: Response to FAK inhibition in MPM is independent of NF2 expression or histotype. FAK inhibition strongly interfered with MPM spheroid formation. BI 853520 has been shown to exert anti-tumor effect in MPM.

Structure-Based Design, Synthesis, and Characterization of the First Irreversible Inhibitor of Focal Adhesion Kinase

Focal Adhesion Kinase signaling pathway and its functions have been involved in the development and aggressiveness of tumor malignancy, it then presents a promising cancer therapeutic target. Several reversible FAK inhibitors have been developed and are being conducted in clinical trials. On the other hand, irreversible covalent inhibitors would bring many desirable pharmacological features including high potency and increased duration of action. Herein we report the structure-guided development of the first highly potent and irreversible inhibitor of the FAK kinase. This inhibitor showed a very potent decrease of autophosphorylation of FAK in squamous cell carcinoma. A cocrystal structure of the FAK kinase domain in complex with this compound revealed the inhibitor binding mode within the ATP binding site and confirmed the covalent linkage between the targeted Cys427 of the protein and the inhibitor.

Berbamine induces SMMC-7721 cell apoptosis via upregulating p53, downregulating survivin expression and activating mitochondria signaling pathway

Hepatocellular carcinoma (HCC) is a primary malignancy in the liver, which is a global health problem. The present study aimed to observe the apoptotic effects of berbamine on SMMC-7721 cell lines and to investigate the effects of berbamine on induction of the intrinsic apoptotic pathway. The human HCC SMMC-7721 cells were cultured and cell morphology observed using a phase contrast microscope. SMMC-7721 cell apoptosis was examined by employing a flow cytometry assay. The nuclei of SMMC-7721 cells were stained with DAPI and observed by utilizing a laser fluorescence microscope. Cytochrome c (Cyto c) levels were evaluated by using immunofluorescence staining. The reverse transcription-semi-quantitative polymerase chain reaction (RT-sqPCR) and western blot analysis were used to examine the mRNA and protein levels of B-cell lymphoma 2, (Bcl-2), Bax, Bcl-2-associated X, apoptosis regulator, p53 and survivin, respectively. Berbamine inhibited SMMC-7721 cell growth at 20 and 0 µmol/l, compared with control group (0 µmol/l berbamine). DAPI results demonstrated that berbamine affected the nucleus morphology of SMMC-7721 cells. Berbamine at a concentration of 20 µmol/l (P<0.05) and 40 µmol/l (P<0.01) significantly enhanced apoptosis rate compared with control group. Berbamine triggered Cyto c release from SMMC-7721 cell nuclei to the cytoplasm. Berbamine (10, 20, 40 µmol/l) significantly enhanced Bax and p53 levels and decreased Bcl-2 and survivin levels compared with control group, according to RT-sqPCR and western blot assay findings. In conclusion, berbamine induced SMMC-7721 cell apoptosis, through upregulating p53 expression and downregulating survivin expression, which further triggered mitochondria signaling pathway-mediated apoptosis.

Efficacy and safety of regorafenib for advanced gastrointestinal stromal tumor after failure with imatinib and sunitinib treatment: A meta-analysis

AIMS

This meta-analysis aimed to evaluate the safety and efficacy of regorafenib as a treatment for patients with advanced (metastatic and/or unresectable) gastrointestinal stromal tumor (AGIST) after developing resistance to imatinib and sunitinib.

METHODS

A literature search of databases such as PubMed, Embase, and Cochrane library was conducted up to February 2017. The pooled percentages and the corresponding 95% confidence intervals (CIs) were calculated using the Stata 11.0 software.

RESULTS

Four studies involving 243 patients with AGIST were included. Results revealed that approximately 49% (95% CI 30-67), 14% (95% CI 5-23), and 41% (95% CI 21-61) of patients with AGIST showed clinical benefit (including complete response), partial response, and stable disease, respectively, after regorafenib treatment, which was given after failure with imatinib and sunitinib treatments. No complete response was found in the included studies. Pooled progression-free survival was 6.58 months (95% CI 4.62-8.54). Hypertension (20%; 95% CI 7-33), hand-foot skin reaction (22%; 95% CI 17-27), and hypophosphatemia (18%; 95% CI 5-41) were common grade ≥3 regorafenib-related adverse events in patients treated with regorafenib after failure with imatinib and sunitinib treatments.

CONCLUSIONS

Forty-nine per cent of patients with AGIST benefited after regorafenib treatment after the development of resistance to imatinib and sunitinib. More studies should be performed to improve the clinical survival of patients with AGIST. Close monitoring and appropriate management of grade ≥3 regorafenib-related adverse events should be considered during treatment.

3D printed scaffolds of calcium silicate-doped β-TCP synergize with co-cultured endothelial and stromal cells to promote vascularization and bone formation

Synthetic bone scaffolds have potential application in repairing large bone defects, however, inefficient vascularization after implantation remains the major issue of graft failure. Herein, porous β-tricalcium phosphate (β-TCP) scaffolds with calcium silicate (CS) were 3D printed, and pre-seeded with co-cultured human umbilical cord vein endothelial cells (HUVECs) and human bone marrow stromal cells (hBMSCs) to construct tissue engineering scaffolds with accelerated vascularization and better bone formation. Results showed that in vitro β-TCP scaffolds doped with 5% CS (5%CS/β-TCP) were biocompatible, and stimulated angiogenesis and osteogenesis. The results also showed that 5%CS/β-TCP scaffolds not only stimulated co-cultured cells angiogenesis on Matrigel, but also stimulated co-cultured cells to form microcapillary-like structures on scaffolds, and promoted migration of BMSCs by stimulating co-cultured cells to secrete PDGF-BB and CXCL12 into the surrounding environment. Moreover, 5%CS/β-TCP scaffolds enhanced vascularization and osteoinduction in comparison with β-TCP, and synergized with co-cultured cells to further increase early vessel formation, which was accompanied by earlier and better ectopic bone formation when implanted subcutaneously in nude mice. Thus, our findings suggest that porous 5%CS/β-TCP scaffolds seeded with co-cultured cells provide new strategy for accelerating tissue engineering scaffolds vascularization and osteogenesis, and show potential as treatment for large bone defects.

Investigations of FAK inhibitors: a combination of 3D-QSAR, docking, and molecular dynamics simulations studies

Focal adhesion kinase (FAK) is one kind of tyrosine kinases that modulates integrin and growth factor signaling pathways, which is a promising therapeutic target because of involving in cancer cell migration, proliferation, and survival. To investigate the mechanism between FAK and triazinic inhibitors and design high activity inhibitors, a molecular modeling integrated with 3D-QSAR, molecular docking, molecular dynamics simulations, and binding free energy calculations was performed. The optimum CoMFA and CoMSIA models showed good reliability and satisfactory predictability (with Q² = 0.663, R² = 0.987, [Formula: see text] = 0.921 and Q² = 0.670, R² = 0.981, [Formula: see text] = 0.953). Its contour maps could provide structural features to improve inhibitory activity. Furthermore, a good consistency between contour maps, docking, and molecular dynamics simulations strongly demonstrates that the molecular modeling is reliable. Based on it, we designed several new compounds and their inhibitory activities were validated by the molecular models. We expect our studies could bring new ideas to promote the development of novel inhibitors with higher inhibitory activity for FAK.

Synthesis of novel 1,2,4-triazine scaffold as FAK inhibitors with antitumor activity

A series of 1,3,5-triazinic inhibitors of focal adhesion kinase (FAK) has recently been shown to exert antiangiogenic activity against HUVEC cells and anticancer efficacy against several cancer cell lines. In this report, we designed and synthesized a series of new compounds containing a 1,2,4-triazine core as novel scaffold for FAK inhibitors. These compounds displayed 10^-7M IC₅₀ values, and the best one showed IC₅₀ value of 0.23μM against FAK enzymatic activity. Among them, several inhibitors potently inhibited the proliferation of glioblastoma (U-87MG) and colon (HCT-116) cancer cell lines. Docking of compound 10 into the active site of the FAK kinase was performed to explore its potential binding mode.

Exploring the interaction between human focal adhesion kinase and inhibitors: a molecular dynamic simulation and free energy calculations

Focal adhesion kinase is an important target for the treatment of many kinds of cancers. Inhibitors of FAK are proposed to be the anticancer agents for multiple tumors. The interaction characteristic between FAK and its inhibitors is crucial to develop new inhibitors. In the present article, we used Molecular Dynamic (MD) simulation method to explore the characteristic of interaction between FAK and three inhibitors (PHM16, TAE226, and ligand3). The MD simulation results together with MM-GB/SA calculations show that the combinations are enthalpy-driven process. Cys502 and Asp564 are both essential residues due to the hydrogen bond interactions with inhibitors, which was in good agreement with experimental data. Glu500 can form a non-classical hydrogen bond with each inhibitor. Arg426 can form electrostatic interactions with PHM16 and ligand3, while weaker with TAE226. The electronic static potential was employed, and we found that the ortho-position methoxy of TAE226 has a weaker negative charge than the meta-position one in PHM16 or ligand3. Ile428, Val436, Ala452, Val484, Leu501, Glu505, Glu506, Leu553, Gly563 Leu567, Ser568 are all crucial residues in hydrophobic interactions. The key residues in this work will be available for further inhibitor design of FAK and also give assistance to further research of cancer.

Role of microRNA-93 in regulation of angiogenesis

Angiogenesis is essential for a wide variety of physiological and pathological processes. To date, many angiogenic microRNAs (miRNAs) have been identified and several of them were further investigated to elucidate the mechanisms of specific miRNAs in regulating angiogenesis. In recent studies concerning tumor and ischemia, the miRNA-93 had been demonstrated to be able to modulate angiogenesis in different molecular pathways. The miRNA-93 can promote angiogenesis via enhancing endothelial cell proliferation, migration, and tube formation. Additionally, miRNA-93-over-expressing cells developed a relationship with the blood vessels allowing tumor cells to survive and to grow well. However, high expression of miRNA-93 can depress the vascular endothelial growth factor (VEGF) secretion and its downstream molecular targets in in vivo and vitro experiments. MiRNA-93's effects on angiogenesis are dependent on the interaction of other multiple genes and signal pathways, such as P21, E2F1, integrin-β8, LATS2, etc. Future investigation should involve mapping the network by which miRNA-93 exerts its functions.

Design, synthesis, and evaluation of novel imidazo[1,2-a][1,3,5]triazines and their derivatives as focal adhesion kinase inhibitors with antitumor activity

A series of triazinic inhibitors of focal adhesion kinase (FAK) have been recently shown to exert antiangiogenic activity against HUVEC cells and anticancer efficacy against several cancer cell lines. We report herein that we further explored the heterocyclic core of these inhibitors by a fused imidazole ring with the triazine to provide imidazo[1,2-a][1,3,5]triazines. Importantly, these new compounds displayed 10(-7)-10(-8) M IC50 values, and the best inhibitor showed IC50 value of 50 nM against FAK enzymatic activity. Several inhibitors potently inhibited the proliferation of a panel of cancer cell lines expressing high levels of FAK. Apoptosis analysis in U87-MG and HCT-116 cell lines suggested that these compounds delayed cell cycle progression by arresting cells in the G2/M phase of the cell cycle, retarding cell growth. Further investigation demonstrated that these compounds strongly inhibited cell-matrix adhesion, migration, and invasion of U87-MG cells.