Combined inhibition of atypical PKC and histone deacetylase 1 is cooperative in basal cell carcinoma treatment.

Advanced basal cell carcinomas (BCCs) circumvent Smoothened (SMO) inhibition by activating GLI transcription factors to sustain the high levels of Hedgehog (HH) signaling required for their survival. Unfortunately, there is a lack of efficacious therapies. We performed a gene expression-based drug repositioning screen in silico and identified the FDA-approved histone deacetylase (HDAC) inhibitor, vorinostat, as a top therapeutic candidate. We show that vorinostat only inhibits proliferation of BCC cells in vitro and BCC allografts in vivo at high dose, limiting its usefulness as a monotherapy. We leveraged this in silico approach to identify drug combinations that increase the therapeutic window of vorinostat and identified atypical PKC Ɩ/ʎ (aPKC) as a HDAC costimulator of HH signaling. We found that aPKC promotes GLI1-HDAC1 association in vitro, linking two positive feedback loops. Combination targeting of HDAC1 and aPKC robustly inhibited GLI1, lowering drug doses needed in vitro, in vivo, and ex vivo in patient-derived BCC explants. We identified a bioavailable and selective small-molecule aPKC inhibitor, bringing the pharmacological blockade of aPKC and HDAC1 into the realm of clinical possibility. Our findings provide a compelling rationale and candidate drugs for combined targeting of HDAC1 and aPKC in HH-dependent cancers.

Discovery of Clinical Candidate CEP-37440, a Selective Inhibitor of Focal Adhesion Kinase (FAK) and Anaplastic Lymphoma Kinase (ALK).

Analogues structurally related to anaplastic lymphoma kinase (ALK) inhibitor 1 were optimized for metabolic stability. The results from this endeavor not only led to improved metabolic stability, pharmacokinetic parameters, and in vitro activity against clinically derived resistance mutations but also led to the incorporation of activity for focal adhesion kinase (FAK). FAK activation, via amplification and/or overexpression, is characteristic of multiple invasive solid tumors and metastasis. The discovery of the clinical stage, dual FAK/ALK inhibitor 27b, including details surrounding SAR, in vitro/in vivo pharmacology, and pharmacokinetics, is reported herein.

The effects of CEP-37440, an inhibitor of focal adhesion kinase, in vitro and in vivo on inflammatory breast cancer cells.

BACKGROUND: Inflammatory breast cancer (IBC) is an aggressive type of advanced breast cancer with a poor prognosis. We recently found that focal adhesion kinase 1 (FAK1) is upregulated and phosphorylated (active) in IBC. In this study, we investigated the effect of CEP-37440, a dual inhibitor of FAK1 and anaplastic lymphoma kinase (ALK), using human IBC cell lines and preclinical models of IBC. METHODS: Cell proliferation assays were performed in the presence of several concentrations of CEP-37440 using IBC and triple-negative breast cancer non-IBC cell lines. In vitro, we studied the expression of total FAK1, phospho-FAK1 (Tyr 397), total ALK and phospho-ALK (Tyr 1604). In vivo, we tested CEP-37440 using FC-IBC02, SUM149, and SUM190 IBC xenograft mouse models. RESULTS: CEP-37440 at low concentration decreased the proliferation of the IBC cell lines FC-IBC02, SUM190, and KPL4, while not affecting the proliferation of normal breast epithelial cells. At higher concentration, CEP-37440 was also able to inhibit the proliferation of the IBC cell line MDA-IBC03 and the triple-negative non-IBC cell lines MDA-MB-231 and MDA-MB-468; the IBC cell line SUM149 showed a slight response to the drug. CEP-37440 decreased the cell proliferation of FC-IBC02, SUM190, and KPL4 by blocking the autophosphorylation kinase activity of FAK1 (Tyr 397). None of the cells evaluated expressed ALK. In vivo, after 7 weeks of CEP-37440 treatment, the SUM190, FC-IBC02, and SUM149 breast tumor xenografts were smaller in mice treated with 55 mg/kg bid CEP-37440 compared to the controls; the tumor growth inhibition (TGI) was 79.7 %, 33 %, and 23 %, respectively. None of the FC-IBC02 breast xenografts mice treated with CEP-37440 developed brain metastasis while 20 % of the mice in the control group developed brain metastasis. Expression array analyses in FC-IBC02 cells showed that CEP-37440 affects the expression of genes related to apoptosis, interferon signaling, and cytokines. CONCLUSIONS: CEP-37440 is effective against some IBC cells that express phospho-FAK1 (Tyr 397), and its antiproliferative activity is related to its ability to decrease phospho-FAK1. Our results suggest that combinational therapies could be more effective than using CEP-37440 as a single agent.

Piperidine-3,4-diol and piperidine-3-ol derivatives of pyrrolo[2,1-f][1,2,4]triazine as inhibitors of anaplastic lymphoma kinase.

The diastereoselective synthesis and biological activity of piperidine-3,4-diol and piperidine-3-ol-derived pyrrolotriazine inhibitors of anaplastic lymphoma kinase (ALK) are described. Although piperidine-3,4-diol and piperidine-3-ol derivatives showed comparable in vitro ALK activity, the latter subset of inhibitors demonstrated improved physiochemical and pharmacokinetic properties. Furthermore, the stereochemistry of the C3 and C4 centers had a marked impact on the in vivo inhibition of ALK autophosphorylation. Thus, trans-4-aryl-piperidine-3-ols (22) were more potent than the cis diastereomers (20).

Anaplastic lymphoma kinase inhibitors as anticancer therapeutics: a patent review.

INTRODUCTION: Anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase from the insulin receptor superfamily, is implicated in the oncogenesis of numerous cancers including anaplastic large-cell lymphoma, non-small-cell lung cancer, diffuse large B-cell lymphoma, inflammatory myofibroblastic tumors, glioblastoma, as well as neuroblastoma. The root cause for these specific cancers has been identified as aberrant ALK kinase activity, which has been shown to be associated with specific gene translocations, single-point mutations, gene amplification and/or overexpression. The direct inhibition of ALK with small-molecule inhibitors represents a viable therapeutic intervention that has achieved clinical proof of concept. AREAS COVERED: Small-molecule ALK inhibitors covered in the patent literature from 2010 to September 2013 are described. Relevant peer-reviewed journal articles that describe discovery and development of the above-identified ALK inhibitors are also discussed. Keyword-based (e.g., ALK, anaplastic lymphoma kinase) literature searches were conducted in Scifinder®. EXPERT OPINION: Novel ALK inhibitors continued to be discovered at a fast pace over the covered period, with many distinct chemotypes emerging. Crizotinib received FDA approval in 2011, and six additional ALK inhibitors have entered clinical trials. The focus of ALK research appears to have shifted toward inhibitors that display activity against resistant mutants unearthed in clinical studies with crizotinib.

Discovery of an orally efficacious inhibitor of anaplastic lymphoma kinase.

Anaplastic lymphoma kinase (ALK) is a promising therapeutic target for the treatment of cancer, supported by considerable favorable preclinical and clinical activities over the past several years and culminating in the recent FDA approval of the ALK inhibitor crizotinib. Through a series of targeted modifications on an ALK inhibitor diaminopyrimidine scaffold, our research group has driven improvements in ALK potency, kinase selectivity, and overall pharmaceutical properties. Optimization of this scaffold has led to the identification of a potent and efficacious inhibitor of ALK, 25b. A striking feature of 25b over previously described ALK inhibitors is its >600-fold selectivity over insulin receptor (IR), a closely related kinase family member. Most importantly, 25b exhibited dose proportional escalation in rat compared to compound 3 which suffered dose limiting absorption preventing further advancement. Compound 25b exhibited significant in vivo antitumor efficacy when dosed orally in an ALK-positive ALCL tumor xenograft model in SCID mice, warranting further assessment in advanced preclinical models.

Design, synthesis, and anaplastic lymphoma kinase (ALK) inhibitory activity for a novel series of 2,4,8,22-tetraazatetracyclo[14.3.1.1³,7.19,¹³]docosa-1(20),3(22),4,6,9(21),10,12,16,18-nonaene macrocycles.

A novel set of 2,4,8,22-tetraazatetracyclo[14.3.1.1(3,7).1(9,13)]docosa-1(20),3(22),4,6,9(21),10,12,16,18-nonaene macrocycles were prepared as potential anaplastic lymphoma kinase (ALK) inhibitors, designed to rigidly lock an energy-minimized bioactive conformation of the diaminopyrimidine (DAP) scaffold, a well-documented kinase platform. From 13 analogues prepared, macrocycle 2m showed the most promising in vitro ALK enzymatic (IC(50) = 0.5 nM) and cellular (IC(50) = 10 nM) activities. In addition, macrocycle 2m exhibited a favorable kinase selectivity preference for inhibition of ALK relative to the highly homologous insulin receptor (IR) kinase (IR/ALK ratio of 173). The inclusive in vitro biological results for this set of macrocycles validate this scaffold as a viable kinase template and further corroborate recent DAP/ALK solid state studies indicating that the inverted "U" shaped conformation of the acyclic DAPs is a preferred bioactive conformation.

Strategies to mitigate the bioactivation of 2-anilino-7-aryl-pyrrolo[2,1-f][1,2,4]triazines: identification of orally bioavailable, efficacious ALK inhibitors.

Chemical strategies to mitigate cytochrome P450-mediated bioactivation of novel 2,7-disubstituted pyrrolo[2,1-f][1,2,4]triazine ALK inhibitors are described along with synthesis and biological activity. Piperidine-derived analogues showing minimal microsomal reactive metabolite formation were discovered. Potent, selective, and metabolically stable ALK inhibitors from this class were identified, and an orally bioavailable compound (32) with antitumor efficacy in ALK-driven xenografts in mouse models was extensively characterized.

CEP-28122, a highly potent and selective orally active inhibitor of anaplastic lymphoma kinase with antitumor activity in experimental models of human cancers.

Anaplastic lymphoma kinase (ALK) is constitutively activated in a number of human cancer types due to chromosomal translocations, point mutations, and gene amplification and has emerged as an excellent molecular target for cancer therapy. Here we report the identification and preclinical characterization of CEP-28122, a highly potent and selective orally active ALK inhibitor. CEP-28122 is a potent inhibitor of recombinant ALK activity and cellular ALK tyrosine phosphorylation. It induced concentration-dependent growth inhibition/cytotoxicity of ALK-positive anaplastic large-cell lymphoma (ALCL), non-small cell lung cancer (NSCLC), and neuroblastoma cells, and displayed dose-dependent inhibition of ALK tyrosine phosphorylation in tumor xenografts in mice, with substantial target inhibition (>90%) for more than 12 hours following single oral dosing at 30 mg/kg. Dose-dependent antitumor activity was observed in ALK-positive ALCL, NSCLC, and neuroblastoma tumor xenografts in mice administered CEP-28122 orally, with complete/near complete tumor regressions observed following treatment at doses of 30 mg/kg twice daily or higher. Treatment of mice bearing Sup-M2 tumor xenografts for 4 weeks and primary human ALCL tumor grafts for 2 weeks at 55 or 100 mg/kg twice daily led to sustained tumor regression in all mice, with no tumor reemergence for more than 60 days postcessation of treatment. Conversely, CEP-28122 displayed marginal antitumor activity against ALK-negative human tumor xenografts under the same dosing regimens. Administration of CEP-28122 was well tolerated in mice and rats. In summary, CEP-28122 is a highly potent and selective orally active ALK inhibitor with a favorable pharmaceutical and pharmacokinetic profile and robust and selective pharmacologic efficacy against ALK-positive human cancer cells and tumor xenograft models in mice.

Pyrazolone-based anaplastic lymphoma kinase (ALK) inhibitors: control of selectivity by a benzyloxy group.

Anaplastic lymphoma kinase (ALK) is transmembrane receptor tyrosine kinase, with oncogenic variants that have been implicated in ALCL, NSCLC and other cancers. Screening of a VEGFR2-biased kinase library resulted in identification of 1 which showed cross-reactivity with ALK. SAR on the indole segment of 1 showed that a subtle structural modification (the ethoxy group of 1 changed to a benzyloxy to generate 5a) enhanced potency (ALK), selectivity for VEGFR2 and IR along with improvement in metabolic stability. From docking studies of ALK versus VEGFR2 kinase, we postulated that the loss of entropy of the VEGFR2 in the bound form with 5a might be the origin of the reduced activity against that protein. Modification of the heterocyclic segment showed that thiazole-bearing pyrazolones preserved enzyme potency, and enhanced inhibition of NPM-ALK autophosphorylation in ALK-positive ALCL cells (Karpas-299). SAR of the benzyloxy group resulted in compounds which demonstrated good cellular potency in Karpas-299 cells. Compound 8 showed best overall profile for the series with broad kinome selectivity and liver micorsome stability. Compound 8 showed reasonable iv PK in rat, but with little oral exposure.

2,7-Disubstituted-pyrrolotriazine kinase inhibitors with an unusually high degree of reactive metabolite formation.

There are numerous published studies establishing a link between reactive metabolite formation and toxicity of various drugs. Although the correlation between idiosyncratic reactions and reactive metabolite formation is not 1:1, the association between the two is such that many pharmaceutical companies now monitor for reactive metabolites as a standard part of drug candidate testing and selection. The most common method involves in vitro human microsomal incubations in the presence of a thiol trapping agent, such as glutathione (GSH), followed by LC/MS analysis. In this study, we describe several 2,7-disubstituted-pyrrolotriazine analogues that are extremely potent reactive metabolite precursors. Utilizing a UPLC/UV/MS method, unprecedented levels of GSH adducts were measured that are 5-10 times higher than previously reported for high reactive metabolite-forming compounds such as clozapine and troglitazone.

2,7-disubstituted-pyrrolo[2,1-f][1,2,4]triazines: new variant of an old template and application to the discovery of anaplastic lymphoma kinase (ALK) inhibitors with in vivo antitumor activity.

A novel 2,7-disubstituted-pyrrolo[2,1-f][1,2,4]triazine scaffold has been designed as a new kinase inhibitor platform mimicking the bioactive conformation of the well-known diaminopyrimidine motif. The design, synthesis, and validation of this new pyrrolo[2,1-f][1,2,4]triazine scaffold will be described for inhibitors of anaplastic lymphoma kinase (ALK). Importantly, incorporation of appropriate potency and selectivity determinants has led to the discovery of several advanced leads that were orally efficacious in animal models of anaplastic large cell lymphoma (ALCL). A lead inhibitor (30) displaying superior efficacy was identified and in depth in vitro/in vivo characterization will be presented.

Methanesulfonamido-cyclohexylamine derivatives of 2,4-diaminopyrimidine as potent ALK inhibitors.

The incorporation of R,R-1,2-diaminocyclohexane at C4 in a series of 2,4-diaminopyrimidines led to a number of ALK inhibitors in which optimized activity was achieved by conversion of the 2-amino group into a methanesulfonamide. Tumor growth inhibition was observed when an orally bioavailable analog was evaluated in a Karpas-299 tumor xenograft mouse model.

Fused bicyclic derivatives of 2,4-diaminopyrimidine as c-Met inhibitors.

The HGF-c-Met signaling axis is an important paracrine mediator of epithelial-mesenchymal cell interactions involving the regulation of multiple cellular activities including cell motility, mitogenesis, morphogenesis, and angiogenesis. Dysregulation of c-Met signaling (e.g., overexpression or increased activation) is associated with the development of a wide range of tumor types; thus, inhibiting the HGF-c-Met pathway is predicted to lead to anti-tumor effects in many cancers. Elaboration of a 2-arylaminopyrimidine scaffold led to a series of potent c-Met inhibitors bearing a C4-2-amino-N-methylbenzamide group. Specifically, a series of C2-benzazepinone analogs demonstrated potent inhibition of c-Met in enzymatic and cellular assays. Kinase selectivity could be tuned by varying the nature of the alkyl group on the benzazepinone nitrogen.

Novel 2,3,4,5-tetrahydro-benzo[d]azepine derivatives of 2,4-diaminopyrimidine, selective and orally bioavailable ALK inhibitors with antitumor efficacy in ALCL mouse models.

The synthesis and biological evaluation of potent and selective anaplastic lymphoma kinase (ALK) inhibitors from a novel class of 2,4-diaminopyrimidines, incorporating 2,3,4,5-tetrahydro-benzo[d]azepine fragments, is described. An orally bioavailable analogue (18) that displayed antitumor efficacy in ALCL xenograft models in mice was identified and extensively profiled.

Inhibitors of anaplastic lymphoma kinase: a patent review.

IMPORTANCE OF THE FIELD: Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase that belongs to the insulin receptor superfamily. Aberrant ALK activity has been implicated in the oncogenesis of human cancers as a fusion protein in anaplastic large cell lymphoma, inflammatory myofibroblastic tumor, diffuse large B-cell lymphoma, systemic histiocytosis and NSCLC or through mutations in the full length protein in hereditary familial neuroblastoma. Thus, abrogation of ALK signaling through direct kinase inhibition has become an attractive therapeutic intervention point for a subset of genetically defined human cancers. AREAS COVERED IN THIS REVIEW: This manuscript provides a comprehensive review of the patent literature pertaining to ALK inhibitors and outlines their potential as anticancer therapeutic agents. WHAT THE READER WILL GAIN: The reader will gain an understanding of the major structural classes of ALK inhibitors and insights into the future of this class of drugs. TAKE HOME MESSAGE: Multiple small-molecule ALK inhibitors have been reported with diverse chemical architecture, potency, kinase selectivity profiles and activity against potential resistance. The breadth of inhibitors combined with the recent discoveries of the involvement of ALK in lung, breast and colorectal cancers has kept the field advancing at a rapid pace.

Anaplastic lymphoma kinase as a therapeutic target in anaplastic large cell lymphoma, non-small cell lung cancer and neuroblastoma.

Anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase in the insulin receptor superfamily, was originally identified as the oncogenic NPM (nucleophosmin)-ALK fusion protein due to a t (2;5) chromosomal translocation in anaplastic large cell lymphomas. Many other chromosomal rearrangements or gene mutations/amplification leading to enhanced ALK activity have subsequently been identified and characterized in a number of human cancer types. The recent reports of EML4 (echinoderm microtubule-associated protein-like 4)-ALK oncogenic proteins in non-small cell lung cancer (NSCLC) and the identification of ALK activating point mutations and gene amplification in neuroblastoma have indicated ALK as a potential major therapeutic target for human cancers. In this review, the role of oncogenic ALK in development of various human cancers is summarized and the efforts and progress of developing small molecule ALK inhibitors as potential cancer therapeutics are updated. Several small molecule ALK inhibitors from distinctive chemical scaffolds in either clinical or preclinical development stage are highlighted and profiled. The challenges and future directions of developing small molecule ALK inhibitors as cancer therapeutics are discussed.

Discovery of a potent inhibitor of anaplastic lymphoma kinase with in vivo antitumor activity.

A series of novel 7-amino-1,3,4,5-tetrahydrobenzo[b]azepin-2-one derivatives within the diaminopyrimidine class of kinase inhibitors were identified that target anaplastic lymphoma kinase (ALK). These inhibitors are potent against ALK in an isolated enzyme assay and inhibit autophosphorylation of the oncogenic fusion protein NPM-ALK in anaplastic large cell lymphoma (ALCL) cell lines. The lead inhibitor 15, which incorporates a bicyclo[2.2.1]hept-5-ene ring system in place of an aryl moiety, activates the pro-apoptotic caspases (3 and 7) and displays selective cytotoxicity against ALK-positive ALCL cells. Furthermore, 15 provides more than 40-fold selectivity against the structurally related insulin receptor, is orally bioavailable in multiple species, and displays in vivo antitumor efficacy when dosed orally in ALK-positive ALCL tumor xenografts in Scid mice.

Potent, exceptionally selective, orally bioavailable inhibitors of TNF-alpha Converting Enzyme (TACE): novel 2-substituted-1H-benzo[d]imidazol-1-yl)methyl)benzamide P1' substituents.

Novel ((2-substituted-1H-benzo[d]imidazol-1-yl)methyl)benzamides were found to be excellent P1' substituents in conjunction with unique constrained beta-amino hydroxamic acid scaffolds for the discovery of potent selective inhibitors of TNF-alpha Converting Enzyme (TACE). Optimized examples proved potent for TACE, exceptionally selective over a wide panel of MMP and ADAM proteases, potent in the suppression of LPS-induced TNF-alpha in human whole blood and orally bioavailable.

Alpha,Beta-cyclic-beta-benzamido hydroxamic acids: Novel oxaspiro[4.4]nonane templates for the discovery of potent, selective, orally bioavailable inhibitors of tumor necrosis factor-alpha converting enzyme (TACE).

Two novel oxaspiro[4.4]nonane beta-benzamido hydroxamic scaffolds have been synthesized in enantio- and diasteriomerically pure form. These templates proved to be exceptional platforms that have led to the discovery of potent inhibitors of TACE that are active in a cellular assay measuring suppression of LPS-induced TNF-alpha. Furthermore, these inhibitors are selective against related MMPs, demonstrate permeability in a Caco-2 assay, and display good oral bioavailability.