Search

The success of imatinib, a BCR-ABL inhibitor for the treatment of chronic myelogenous leukemia, has created a great impetus for the development of additional kinase inhibitors as therapeutic agents. However, the complexity of cancer has led to recent interest in polypharmacological approaches for developing multikinase inhibitors with low toxicity profiles. With this goal in mind, we analyzed more than 150 novel cyano pyridopyrimidine compounds and identified structure–activity relationship trends that can be exploited in the design of potent kinase inhibitors. One compound, 8-cyclopentyl-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidine-6-carbonitrile (7x), was found to be the most active, inducing apoptosis of tumor cells at a concentration of approximately 30–100 nM. In vitro kinase profiling revealed that 7x is a multikinase inhibitor with potent inhibitory activity against the CDK4/CYCLIN D1 and ARK5 kinases. Here, we report the synthesis, structure–activity relationship, kinase inhibitory profile, in vitro cytotoxicity, and in vivo tumor regression studies by this lead compound.

Cyclin D proteins are elevated in many cancer cells and targeted deletion of Cyclin D1 gene in the mammary tissues protects mice from breast cancer. Accordingly, there is an increasing awareness of this novel non-enzymatic target for cancer therapeutics. We have developed novel, non-alkylating styryl benzyl sulfones that induce cell death in wide variety of cancer cells without affecting the proliferation and survival of normal cells. The development of derivatized Styryl Benzyl Sulfones followed logically from a tumor cell cytotoxicity screen performed in our laboratory that did not have an a priori target profile. Modifications of some of the precursor molecules led to lead optimization with regard to tumor cell cytotoxicity. In this report we describe the synthesis and structure-activity relationships of novel, non-alkylating (E) styryl benzyl sulfones, and the development of the novel anti-cancer agent sodium (E)-2-{2-methoxy-5-[(2′,4′,6′-trimethoxystyrylsulfonyl)methyl]phenylamino}-acetate (ON 01910.Na), which is in Phase III trials for myelodysplastic syndromes (MDS) associated with aberrant expression of cyclin D proteins.

Mammalian cell culture systems are used predominantly for the production of therapeutic monoclonal antibody (mAb) products. A number of alternative platforms, such as Pichia engineered with a humanized N-linked glycosylation pathway, have recently been developed for the production of mAbs. The glycosylation profiles of mAbs produced in glycoengineered Pichia are similar to those of mAbs produced in mammalian systems. This report presents for the first time the comprehensive characterization of an anti-human epidermal growth factor receptor 2 (HER2) mAb produced in a glycoengineered Pichia, and a study comparing the anti-HER2 from Pichia, which had an amino acid sequence identical to trastuzumab, with trastuzumab. The comparative study covered a full spectrum of preclinical evaluation, including bioanalytical characterization, in vitro biological functions, in vivo anti-tumor efficacy and pharmacokinetics in both mice and non-human primates. Cell signaling and proliferation assays showed that anti-HER2 from Pichia had antagonist activities comparable to trastuzumab. However, Pichia-produced material showed a 5-fold increase in binding affinity to FcγIIIA and significantly enhanced antibody dependant cell-mediated cytotoxicity (ADCC) activity, presumably due to the lack of fucose on N-glycans. In a breast cancer xenograft mouse model, anti-HER2 was comparable to trastuzumab in tumor growth inhibition. Furthermore, comparable pharmacokinetic profiles were observed for anti-HER2 and trastuzumab in both mice and cynomolgus monkeys. We conclude that glycoengineered Pichia provides an alternative production platform for therapeutic mAbs and may be of particular interest for production of antibodies for which ADCC is part of the clinical mechanism of action.

The growing antibody market and the pressure to improve productivity as well as reduce cost of production have fueled the development of alternative expression systems. The therapeutic function of many antibodies is influenced by N-linked glycosylation, which is affected by a combination of the expression host and culture conditions. This paper reports the generation of a glycoengineered Pichia pastoris strain capable of producing more than 1 g l(-1) of a functional monoclonal antibody in a robust, scalable and portable cultivation process with uniform N-linked glycans of the type Man(5)GlcNAc(2). N-linked glycan uniformity and volumetric productivity have been maintained across a range of cultivation process conditions including pH (5.5-7.5), temperature (16-24 degrees C), dissolved oxygen concentration (0.85-3.40 mg l(-1)) and specific methanol feed rate (9-19 mg g(-1) h(-1)) as well as across different cultivation scales (0.5, 3.0, 15 and 40 l). Compared to a marketed CHO-produced therapeutic antibody, the glycoengineered yeast-produced antibody has similar motilities on SDS-PAGE, comparable size exclusion chromatograms (SEC) and antigen binding affinities. This paper provides proof of concept that glycoengineered yeast can be used to produce functional full-length monoclonal antibodies at commercially viable productivities.

A new series of styryl acetoxyphenyl sulfides and sulfones possessing (E)- and (Z)-configurations were designed and prepared by stereospecific syntheses. All these compounds were evaluated for their ability to inhibit COX-2 enzyme in vitro. Structure-activity relationship studies on these compounds revealed that only sulfides with (Z)-configuration have potential COX-2 inhibitory activity. This inactivation of the enzyme is believed to be due to the selective covalent modification of COX-2 by the inhibitors.

A series of novel (E)-N-aryl-2-arylethenesulfonamides (6) were synthesized and evaluated for their anticancer activity. Some of the compounds in this series showed potent cytotoxicity against a wide spectrum of cancer cell-lines (IC50 values ranging from 5 to 10 nM) including all drug resistant cell-lines. Nude mice xenograft assays with compound (E)-N-(3-amino-4-methoxyphenyl)-2-(2',4',6'-trimethoxyphenyl)ethenesulfonamide (6t) showed dramatic reduction in tumor size, indicating their in vivo potential as anticancer agents. A preliminary drug development study with compound 6t is predicted to have increased blood-brain barrier permeability relative to many clinically used antimitotic agents. Mechanistic studies indicate that 6t and some other analogues disrupted microtubule formation, formation of mitotic spindles, and arrest of cells in mitotic phase. Compound 6t inhibited purified tubulin polymerization in vitro and in vivo and circumvented drug resistance mediated by P-glycoprotein. Compound 6t specifically competed with colchicine binding to tubulin and with similar avidity as podophylltoxin, indicating its binding site on tubulin.

Previous studies have shown that glycoproteins expressed in wild-type Pichia pastoris bind to Dendritic cell-SIGN (DC-Specific Intercellular adhesion molecule-3 Grabbing Nonintegrin), a mannose-binding receptor found on dendritic cells in peripheral tissues which is involved in antigen presentation and the initiation of an immune response. However, the binding of DC-SIGN to glycoproteins purified from P. pastoris strains engineered to express humanized N- and O-linked glycans has not been tested to date. In this study, the binding of glycoproteins with specific high-mannose or human N- and O-linked glycan structures to DC-SIGN was tested. Proteins with humanized N-glycans including Man5 structures and O-glycans (up to as many as 24) with single mannose chain length showed DC-SIGN binding that was comparable to that measured for a CHO-produced IgG1 which lacks O-linked mannose. Glycoproteins with wild-type N-glycans and mannotriose and higher O-glycans bound to DC-SIGN in a manner that was strongly inhibited by either the use of enzymatic N-deglycosylation or sodium meta-periodate oxidation. Mannan purified from humanized P. pastoris also showed lower ability to inhibit DC-SIGN binding to glycoproteins with wild type fungal glycosylation than mannan purified from wild type strains. This study shows that humanized P. pastoris can produce glycoproteins that do not bind to DC-SIGN.

Tubulin, the major structural component of microtubules, is a target for the development of anticancer agents. A series of (Z)-1-Aryl-3-arylamino-2-propen-1-one (10) were synthesized and evaluated for anti-proliferative activity in cell based assay. The most active compound (Z)-1-(2- bromo-3,4,5-trimethoxyphenyl)-3-(3-hydroxy-4-methoxyphenylamino)-prop-2-en-1-one (10ae) was tested in 20 tumor cell lines including multidrug resistant phenotype and was found to induce apoptosis in all these cell lines with similar GI50 values. Flow cytometry studies showed that 10ae arrested the cells in G2/M phase of cell cycle. In addition to G2/M block, these compounds caused microtubule stabilization like paclitaxel and induced apoptosis via activation of the caspase family. The observations made in this investigation demonstrate that (Z)-1-Aryl-3- arylamino-2-propen-1-one (10) represents a new class of microtubule – stabilizing agents.

Introduction: Recent proof-of-concept for targeting cyclin dependent kinases 4 and 6 (CDK4/6) culminated in the approval for breast cancer of the first-in-class CDK4/6 inhibitor, palbociclib (Ibrance®). Palbociclib and other potent but narrowly targeted CDK4/6 inhibitors are cytostatic rather than cytotoxic (Leonard et al, 2012), and require combination therapy for optimal activity. ON 123300 is a next-generation CDK4/6 inhibitor with improved single-agent cytotoxicity. This novel compound is a potent CDK4 and CDK6 inhibitor (IC50 = 3.9 nM and 9.8 nM, respectively) that is cytotoxic against breast and other cancer cell lines (Reddy et al, 2014). We present pre-IND profiling pharmacology, physicochemical and ADME studies to support ON 123300 as a clinical candidate and next-generation CDK4/6 inhibitor. Methods and Results: Non-clinical studies were conducted in order to assess the drug-like properties of ON 123300 and its pharmaceutical salts. Physicochemical parameters were determined for the compound. ON 123300 was highly soluble below pH 4.0, with reduced solubility in more basic conditions. Predicted intestinal absorption, as measured by Caco-2 permeability, was 1.95×10-5 cm/s with a low efflux ratio. Based on these characteristics, the compound was advanced to lead profiling against 68 primary molecular targets. Radioligand binding studies revealed limited receptor inhibition (11/68 targets) with 10 μM of ON 123300. Human Ether-a-go-go (hERG) inhibition testing revealed no significant effect (IC50 > 25 μM). In vitro metabolism studies indicated metabolism through CYP3A4 and CYP2C8. Finally, in silico based modeling (Cloe® PK) integrating all key non-clinical parameters was carried out in order to estimate the potential for oral absorption in humans. Preliminary analysis suggests good oral bioavailability and the potential to establish an acceptable therapeutic window. Conclusions: The well differentiated biochemical, anticancer and pharmaceutical properties of ON 123300 provide the basis for pre-clinical toxicology testing, leading to an investigational new drug (IND) filing and clinical exploration of this compound across tumor types that share targets accessed by this next-generation CDK inhibitor. Citation Format: Benjamin Hoffman, Ramana Reddy, Muralidhar Mallireddigari, Daniel Fox, Chen Ren, Manoj Maniar. Single-agent activity and favorable pharmaceutical properties of orally bioavailable next-generation CDK4/6 inhibitor, ON 123300. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr LB-A21.

A series of 20 novel 1-(4-sulfamylphenyl)-3-trifluoromethyl-5-indolyl pyrazolines were designed, synthesized, and screened in vitro for anti-inflammatory activity. These compounds were designed for evaluation as dual inhibitors of cyclooxygenases (COX-1 and COX-2) and lipoxygenases (LOX-5, LOX-12, and LOX-15) that are responsible for inflammation and pain. All pyrazoline molecules prepared are optically active and compounds that are more potent in COX-2 inhibitory activity (5a and 5f) were resolved by chiral column and each enantiomer was tested for cyclooxygenase inhibitory activity. Molecular modeling and comparison of molecular models of 5a enantiomers with that of celecoxib model shows that 5a (enantiomer-1) and 5a (enantiomer-2) have more hydrogen bonding interactions in the catalytic domain of COX-2 enzyme than celecoxib. Compounds 5a, 5e, and 5f showed moderate to good LOX-5 and LOX-15 inhibitory activity and this is comparable to that of celecoxib and more potent than rofecoxib.

e13562 Background: The signal transducer and activator of transcription (STAT) family of proteins are important intracellular mediators. Two of these family members, STAT3 and STAT5, have been foun...