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 multi kinase 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 30–100nM. In vitro kinase profiling revealed that 7x is a multi-kinase 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.

Triple negative breast cancer (TNBC) remains challenging because of heterogeneous responses to chemotherapy. Incomplete response is associated with a greater risk of metastatic progression. Therefore, treatments that target chemotherapy-resistant TNBC and enhance chemosensitivity would improve outcomes for these high-risk patients. Breast cancer stem cell-like cells (BCSCs) have been proposed to represent a chemotherapy-resistant subpopulation responsible for tumor initiation, progression and metastases. Targeting this population could lead to improved TNBC disease control. Here, we describe a novel multi-kinase inhibitor, 108600, that targets the TNBC BCSC population. 108600 treatment suppresses growth, colony and mammosphere forming capacity of BCSCs and induces G2M arrest and apoptosis of TNBC cells. In vivo, 108600 treatment of mice bearing triple negative tumors results in the induction of apoptosis and overcomes chemotherapy resistance. Finally, treatment with 108600 and chemotherapy suppresses growth of pre-established TNBC metastases, providing additional support for the clinical translation of this agent to clinical trials.

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.

Novel amino-pyrazolone, amino-isoxazolone and amino-pyrimidinone derivatives were prepared from ethyl 4-phenylsulfonyl-2-(2-phenylsulfonylethyl)-2-cyanobutyrate (1), ethyl 4-arylsulfonyl-3-aryl-2-cyanobutyrate (7) and ethyl 4-arylmethylsulfonyl-3-aryl-2-cyanobutyrate (8). The lead molecules have been tested for their antimicrobial activity and antioxidant property.

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 anti-mitotic agents. Mechanistic studies indicate that 6t and some other analogs 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.