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Focal adhesion kinase (FAK) is overexpressed in highly invasive and metastatic cancers. To identify novel FAK inhibitors, we designed and synthesized various thieno[3,2- d ]pyrimidine derivatives. An intensive structure-activity relationship (SAR) study led to the identification of 26 as a lead. Moreover, 26 , a multitargeted kinase inhibitor, possesses excellent potencies against FLT3 mutants as well as FAK. Gratifyingly, 26 remarkably inhibits recalcitrant FLT3 mutants, including F691L, that cause drug resistance. Importantly, 26 is superior to PF-562271 in terms of apoptosis induction, anchorage-independent growth inhibition, and tumor burden reduction in the MDA-MB-231 xenograft mouse model. Also, 26 causes regression of tumor growth in the MV4-11 xenograft mouse model, indicating that it could be effective against acute myeloid leukemia (AML). Finally, in an orthotopic mouse model using MDA-MB-231, 26 remarkably prevents metastasis of orthotopic tumors to lymph nodes. Taken together, the results indicate that 26 possesses potential therapeutic value against highly invasive cancers and relapsed AML.

Bromodomains have been pursued intensively over the past several years as emerging targets for the development of anticancer and anti-inflammatory agents. It has recently been shown that some kinase inhibitors are able to potently inhibit the bromodomains of BRD4. The clinical activities of PLK inhibitor BI-2536 and JAK2-FLT3 inhibitor TG101348 have been attributed to this unexpected polypharmacology, indicating that dual-kinase/bromodomain activity may be advantageous in a therapeutic context. However, for target validation and biological investigation, a more selective target profile is desired. Here, we report that benzo[e]pyrimido-[5,4- b]diazepine-6(11H)-ones, versatile ATP-site directed kinase pharmacophores utilized in the development of inhibitors of multiple kinases, including several previously reported kinase chemical probes, are also capable of exhibiting potent BRD4-dependent pharmacology. Using a dual kinase-bromodomain inhibitor of the kinase domains of ERK5 and LRRK2, and the bromodomain of BRD4 as a case study, we define the structure-activity relationships required to achieve dual kinase/BRD4 activity, as well as how to direct selectivity toward inhibition of either ERK5 or BRD4. This effort resulted in identification of one of the first reported kinase-selective chemical probes for ERK5 (JWG-071), a BET selective inhibitor with 1 μM BRD4 IC 50 (JWG-115), and additional inhibitors with rationally designed polypharmacology (JWG-047, JWG-069). Co-crystallography of seven representative inhibitors with the first bromodomain of BRD4 demonstrate that distinct atropisomeric conformers recognize the kinase ATP-site and the BRD4 acetyl lysine binding site, conformational preferences supported by rigid docking studies.

Her3 is a member of the human epidermal growth factor receptor (EGFR) tyrosine kinase family, and it is often either overexpressed or deregulated in many types of human cancer. Her3 has not been the subject of small-molecule inhibitor development because it is a pseudokinase and does not possess appreciable kinase activity. We recently reported on the development of the first selective irreversible Her3 ligand (TX1-85-1) that forms a covalent bond with cysteine 721 which is unique to Her3 among all kinases. We also developed a bi-functional compound (TX2-121-1) containing a hydrophobic adamantane moiety and the same warhead of TX1-85-1 that is capable of inhibiting Her3-dependent signaling and growth. Here we report on the structure-based medicinal chemistry effort that resulted in the discovery of these two compounds., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

GNF-2 and GNF-5 are members of a new class of non-receptor tyrosine kinases inhibitors that possess excellent selectivity towards imatinib-resistant mutations found in chronic myeloid leukemia patients. On the other hand recent reports implicate abnormal tyrosine kinase signaling in β-cell death in Type I and Type II diabetes. In this work we determined the effects of GNF-2, GNF-5 on pancreatic β-cell death caused by streptozotocin (STZ). STZ treatment causes apoptosis of INS-1 cells by activation of intracellular ROS, c-jun N-terminal kinase (JNK), caspase 3, and caspase 3-dependent activation of protein kinase C delta (PKCδ). GNF-2 and GNF-5 increased cell viability and attenuated STZ-induced intracellular ROS and significantly reduced the activation of JNK, caspase 3, and caspase 3-dependent activation of PKCδ. In studies with intact mice, GFN-2 and GNF-5 prevented the loss of beta cells and the increase in blood glucose produced by STZ-treated control mice. Furthermore, immunohistochemical analysis revealed that GNF-2 and GNF-5 increased insulin protein levels in STZ-treated mice when compared with control mice. These findings suggest that non-receptor tyrosine kinase inhibitors provide a new approach for the treatment of new-onset Type I and Type II diabetes., (Copyright © 2015 Elsevier Inc. All rights reserved.)

With the aim of discovering potent and selective kinase inhibitors targeting ROS1 kinase, we designed, synthesized and screened a series of new pyrazol-4-ylpyrimidine derivatives based on our previously discovered lead compound KIST301072. Compounds 6a-e and 7a-e showed good to excellent activities against ROS1 kinase, and seven out of tested compounds were more potent than KIST301072. Compound 7c was the most potent with IC50 of 24 nM. Moreover, compound 7c showed ROS1 inhibitory selectivity of about 170-fold, relative to that of ALK sharing about 49% amino acid sequence homology with ROS1 kinase in the kinase domain. In silico modeling of 7c at ROS1 active site revealed some essential features for ROS1 inhibitory activity. Based on this study as well as the previous studies, we could build a hypothetical model predicting the required essential features for ROS1 inhibitory activity. The model validity has been tested through a second set of compounds., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Synthesis of a new series of quinolinylaminopyrimidines 1a-k and quinazolinylmethylaminopyrimidines 2a-i containing aminoquinoline and aminoquinazoline as hinge regions is described. Their in vitro antiproliferative activities against A375P human melanoma cell line were tested. Among them, compounds 1h and 1k exhibited the highest antiproliferative activities against A375P cell line with IC50 values in sub-micromolar scale. Compounds 1i, 2b and 2g showed similar potency against A375P to Sorafenib as a reference compound. The representative compound 1h showed high, dose-dependent inhibition of MEK and ERK kinases.

Tumour oncogenes include transcription factors that co-opt the general transcriptional machinery to sustain the oncogenic state, but direct pharmacological inhibition of transcription factors has so far proven difficult. However, the transcriptional machinery contains various enzymatic cofactors that can be targeted for the development of new therapeutic candidates, including cyclin-dependent kinases (CDKs). Here we present the discovery and characterization of a covalent CDK7 inhibitor, THZ1, which has the unprecedented ability to target a remote cysteine residue located outside of the canonical kinase domain, providing an unanticipated means of achieving selectivity for CDK7. Cancer cell-line profiling indicates that a subset of cancer cell lines, including human T-cell acute lymphoblastic leukaemia (T-ALL), have exceptional sensitivity to THZ1. Genome-wide analysis in Jurkat T-ALL cells shows that THZ1 disproportionally affects transcription of RUNX1 and suggests that sensitivity to THZ1 may be due to vulnerability conferred by the RUNX1 super-enhancer and the key role of RUNX1 in the core transcriptional regulatory circuitry of these tumour cells. Pharmacological modulation of CDK7 kinase activity may thus provide an approach to identify and treat tumour types that are dependent on transcription for maintenance of the oncogenic state.

The benzo[e]pyrimido-[5,4-b]diazepine-6(11H)-one core was discovered as a novel ERK5 (also known as MAPK7 and BMK1) inhibitor scaffold, previously. Further structure-activity relationship studies of this scaffold led to the discovery of ERK5-IN-1 (26) as the most selective and potent ERK5 inhibitor reported to date. 26 potently inhibits ERK5 biochemically with an IC₅₀ of 0.162 ± 0.006 μM and in cells with a cellular EC₅₀ for inhibiting epidermal growth factor induced ERK5 autophosphorylation of 0.09 ± 0.03 μM. Furthermore, 26 displays excellent selectivity over other kinases with a KINOMEscan selectivity score (S₁₀) of 0.007, and exhibits exceptional bioavailability (F%) of 90% in mice. 26 will serve as a valuable tool compound to investigate the ERK5 signaling pathway and as a starting point for developing an ERK5 directed therapeutic agent., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Inhibition of Bcr-Abl kinase activity by imatinib for the treatment of chronic myeloid leukemia (CML) currently serves as the paradigm for targeting dominant oncogenes with small molecules. We recently reported the discovery of GNF-2 (1) and GNF-5 (2) as selective non-ATP competitive inhibitors of cellular Bcr-Abl kinase activity that target the myristate binding site. Here, we used cell-based structure-activity relationships to guide the optimization and diversification of ligands that are capable of binding to the myristate binding site and rationalize the findings based upon an Abl-compound 1 cocrystal. We elucidate the structure-activity relationships required to obtain potent antiproliferative activity against Bcr-Abl transformed cells and report the discovery of new compounds (5g, 5h, 6a, 14d, and 21j-I) that display improved potency or pharmacological properties. This work demonstrates that a variety of structures can effectively target the Bcr-Abl myristate binding site and provides new leads for developing drugs that can target this binding site.

The second generation of Bcr-Abl inhibitors nilotinib, dasatinib, and bosutinib developed to override imatinib resistance are not active against the T315I "gatekeeper" mutation. Here we describe a type-II T315I inhibitor 2 (GNF-7), based upon a 3,4-dihydropyrimido[4,5-d]pyrimidin-2(1H)-one scaffold which is capable of potently inhibiting wild-type and T315I Bcr-Abl as well as other clinically relevant Bcr-Abl mutants such as G250E, Q252H, Y253H, E255K, E255V, F317L, and M351T in biochemical and cellular assays. In addition, compound 2 displayed significant in vivo efficacy against T315I-Bcr-Abl without appreciable toxicity in a bioluminescent xenograft mouse model using a transformed T315I-Bcr-Abl-Ba/F3 cell line that has a stable luciferase expression. Compound 2 is among the first type-II inhibitors capable of inhibiting T315I to be described and will serve as a valuable lead to design the third generation Bcr-Abl kinase inhibitors.

The synthesis of a novel series of pyrimidin-4-yl-1H-imidazol-2-yl derivatives 7, 8, 9 and their antiproliferative activities against A375P human melanoma cell line and WM3629 cell line were described. Most compounds showed superior antiproliferative activities compared to Sorafenib, the well-known RAF inhibitor. Among them, 7a exhibited potent activities on both cell lines (IC(50)=0.62 and 4.49muM, respectively) and turned out to be a selective and potent CRAF inhibitor., (Copyright 2010 Elsevier Ltd. All rights reserved.)

A series of 4-amino-6-benzimidazole-pyrimidines was designed to target lymphocyte-specific tyrosine kinase (Lck), a member of the Src-family kinases (SFKs). These type II inhibitors were optimized using a cellular Lck-dependent proliferation assay and are capable of inhibiting Lck at single-digit nanomolar concentrations. This scaffold is likely to serve a valuable template for developing potent inhibitors of a number of SFKs.

A series of 4-amino-6-benzimidazole-pyrimidines was designed to target lymphocyte-specific tyrosine kinase (Lck), a member of the Src kinase family. Highly efficient parallel syntheses were devised to prepare analogues for SAR studies. A number of these 4-amino-6-benzimidazole-pyrimidines exhibited single-digit nanomolar IC(50)s against Lck in biochemical and cellular assays. These 4-amino-6-benzimidazole-pyrimidines represent a new class of tyrosine kinase inhibitors.

Chronic myelogenous leukemia (CML) is a myeloproliferative disorder characterized at the molecular level by the expression of Bcr-abl, a 210-kDa fusion protein with deregulated tyrosine kinase activity. Encouraged by the clinical validation of Bcr-abl as the target for the treatment of CML by imatinib, we sought to identify pharmacological agents that could target this kinase by a distinct mechanism. We report the discovery of a new class of Bcr-abl inhibitors using an unbiased differential cytotoxicity screen of a combinatorial kinase-directed heterocycle library. Compounds in this class (exemplified by GNF-2) show exclusive antiproliferative activity toward Bcr-abl-transformed cells, with potencies similar to imatinib, while showing no inhibition of the kinase activity of full-length or catalytic domain of c-abl. We propose that this new class of compounds inhibits Bcr-abl kinase activity through an allosteric non-ATP competitive mechanism.