Design, synthesis and biological evaluation of 2,3-dihydroimidazo[2,1-b]thiazoles as dual EGFR and IGF1R inhibitors.

Herein we describe the design, synthesis and anticancer evaluation of a series of 2,3-dihydroimidazo[2,1-b]thiazoles as dual kinase inhibitors of IGF1R and EGFR. A series of saturated dihydroimidazo[2,1-b] thiazoles were synthesized to understand the structure-activity relationship. Further, the key modifications were performed to improve drug like properties of the series. A 2-oxa-6-azaspiro [3.3] heptane moiety was incorporated as a bioisosteric replacement of morpholine on dihydroimidazo[2,1-b] thiazole scaffold.Subsequent structure-activity relationship (SAR) studies identified several compounds with nM range of activity. The compound 18a shows promising activity, IC50 = 52 nM against IGF1R and IC50 = 35.5 nM against EGFR with descent PK profile. The identified leadshows promising activity against both wild type and the T790M mutant forms of enzymes.

P7170: A Novel Molecule with Unique Profile of mTORC1/C2 and Activin Receptor-like Kinase 1 Inhibition Leading to Antitumor and Antiangiogenic Activity.

The mTOR pathway is often upregulated in cancer and thus intensively pursued as a target to design novel anticancer therapies. Approved and emerging drugs targeting the mTOR pathway have positively affected the clinical landscape. Recently, activin receptor-like kinase 1 (ALK1), belonging to the TGFß receptor family, has been reported as an emerging target for antiangiogenic cancer therapy. Here, we describe a novel orally efficacious compound, P7170, that inhibits mTORC1/mTORC2/ALK1 activity with a potent cell growth inhibition. In cell-based assays, P7170 strongly inhibited (IC50 < 10 nmol/L) the phosphorylation of p70S6K (T389) and pAKT (S473). In many cancer cell lines, such as prostate, ovarian, colon, and renal, P7170 treatment resulted in marked cell growth inhibition. Furthermore, it induced G1-S cell-cycle arrest and autophagy. In vitro HUVEC tube formation, in vivo Matrigel plug, and rat aorta ring assays demonstrated that P7170 exhibited significant antiangiogenic activity. In addition, ALK1 knockdown studies in HUVEC confirmed that the antiangiogenic activity of P7170 was primarily due to ALK1 inhibition. Strong inhibition of ALK1 in addition to mTORC1/mTORC2 differentiates P7170 in its mechanism of action in comparison with existing inhibitors. In vivo mouse xenograft studies revealed P7170 to exhibit a significant dose-dependent tumor growth inhibition in a broad range of human tumor types when administered orally at 10 to 20 mg/kg doses. The distinctive pharmacological profile with favorable pharmacokinetic parameters and in vivo efficacy makes P7170 an attractive candidate for clinical development. It is currently being tested in phase I clinical studies.

Cyclopentyl-pyrimidine based analogues as novel and potent IGF-1R inhibitor.

A series of novel 2-amino-4-pyrazolecyclopentylpyrimidines have been prepared and evaluated as IGF-1R tyrosin kinase inhibitors. The in vitro activity was found to depend strongly on the substitution pattern in the 2- amino ring, 4-pyrazolo moieties and size of fused saturated ring with the central pyrimidine core. A stepwise optimization by combination of active fragments led to discovery of compound 6f and 6k, two structures with IGF-1R IC50 of 20 nM and 10 nM, respectively. 6f was further profiled for its anti cancer activity across various cell lines and pharmacokinetic studies in Sprague Dawley rats.

P7170, a novel inhibitor of mTORC1/mTORC2 and Activin receptor-like Kinase 1 (ALK1) inhibits the growth of non small cell lung cancer.

BACKGROUND: Lung cancer is the major cause of cancer-related deaths and many cases of Non Small Cell Lung Cancer (NSCLC), a common type of lung cancer, have frequent genetic/oncogenic activation of EGFR, KRAS, PIK3CA, BRAF, and others that drive tumor growth. Some patients though initially respond, but later develop resistance to erlotinib/gefitinib with no option except for cytotoxic therapy. Therefore, development of novel targeted therapeutics is imperative to provide improved survival benefit for NSCLC patients. The mTOR cell survival pathway is activated in naïve, or in response to targeted therapies in NSCLC. METHODS: We have discovered P7170, a small molecule inhibitor of mTORC1/mTORC2/ALK1 and investigated its antitumor efficacy using various in vitro and in vivo models of human NSCLC. RESULTS: P7170 inhibited the phosphorylation of AKT, S6 and 4EBP1 (substrates for mTORC2 and mTORC1) levels by 80-100% and growth of NSCLC cells. P7170 inhibited anchorage-independent colony formation of NSCLC patient tumor-derived cells subsistent of disease sub-types. The compound also induced apoptosis in NSCLC cell lines. P7170 at a well-tolerated daily dose of 20 mg/kg significantly inhibited the growth of NSCLC xenografts independent of different mutations (EGFR, KRAS, or PIK3CA) or sensitivity to erlotinib. Pharmacokinetic-pharmacodynamic (PK-PD) analysis showed sub-micro molar tumor concentrations along with mTORC1/C2 inhibition. CONCLUSIONS: Our results provide evidence of antitumor activity of P7170 in the erlotinib -sensitive and -insensitive models of NSCLC.

Synthesis and evaluation of cyclohexane carboxylic acid head group containing isoxazole and thiazole analogs as DGAT1 inhibitors.

Diacylglycerol acyltransferase 1 (DGAT1) is known to play an important catalytic role in the final step of triglyceride biosynthesis. High fat diet fed DGAT1 knockout mice were resistant to weight gain and exhibited increased insulin and leptin sensitivity thereby indicating a plausible role for DGAT1 inhibitors in the treatment of obesity. 4-Phenylpiperidine-1-carbonyl cyclohexanecarboxylic acid (compound 6, DGAT1 IC50 = 57 nM) has been lately reported as a potent DGAT1 inhibitor. In our search for newer scaffolds possessing potent DGAT1 activity we undertook a systematic diversification of compound 6 to identify a 4-(5-phenylthiazole-2-carboxamido)cyclohexanecarboxylic acid scaffold. Further linker optimization of this scaffold identified compound 9e (DGAT1 IC50 = 14.8 nM) as a potent DGAT1 inhibitor. Coupled with its in vitro potency, compound 9e also exhibited 112 percent plasma triglyceride reduction at a 3 mpk dose in an oral fat tolerance test (FTT) when studied in Swiss mice.

Discovery of thiazolyl-phthalazinone acetamides as potent glucose uptake activators via high-throughput screening.

With the aim to discover orally active small molecules that stimulate glucose uptake, high throughput screening of a library of 5000 drug-like compounds was conducted in differentiated skeletal muscle cells in presence of insulin. N-Substituted phthalazinone acetamide was identified as a potential glucose uptake modulator. Several novel derivatives were synthesized to establish structure activity relationships. Identified lead thiazolyl-phthalazinone acetamide (7114863) increased glucose uptake (EC50 of 0.07±0.02 µM) in differentiated skeletal muscle cells in presence of insulin. Furthermore, 7114863 was superior to rosiglitazone under similar experimental conditions without inducing PPAR-γ agonist activity thus making it a very interesting scaffold.

Novel derivative of benzofuran induces cell death mostly by G2/M cell cycle arrest through p53-dependent pathway but partially by inhibition of NF-kappaB.

The Dracaena resin is widely used in traditional medicine as an anticancer agent, and benzofuran lignan is the active component. In this report, we provide evidence that the synthetic derivative of benzofuran lignan (Benfur) showed antitumor activities. It induced apoptosis in p53-positive cells. Though it inhibited endotoxin-induced nuclear factor kappaB (NF-kappaB) activation in both p53-positive and -negative cells, the activation of caspase 3 was observed in p53-positive cells. It showed partial cell death effect in both p53-positive and -negative cells through inhibition of NF-kappaB. Cell cycle analysis using flow cytometry showed that treatment with this novel benozofuran lignan derivative to Jurkat T-cells, but not U-937 cells, resulted in a G2/M arrest in a dose- and time-dependent manner. It increased amounts of p21, p27, and cyclin B, but not phospho-Rb through p53 nuclear translocation in Jurkat T-cells, but not in U-937 cells. It inhibited amounts of MDM2 (murine double minute 2) by repressing the transcription factor Sp1, which was also proved in silico. It induced cell death in tumor cells, but not in primary T-cells. Overall, our data suggest that Benfur-mediated cell death is partially dependent upon NF-kappaB, but predominantly dependent on p53. Thus, this novel benzofuran lignan derivative can be effective chemopreventive or chemotherapeutic agent against malignant T-cells.

A dihydrobenzofuran lignan induces cell death by modulating mitochondrial pathway and G2/M cell cycle arrest.

A dihydrobenzofuran lignan, the dimerization product of caffeic acid methyl ester, has shown pronounced antileishmanial and antiplasmodial activities. The present study showed the effect of this compound on cell cycle and apoptosis. Flow cytometric analysis revealed that the cells were arrested in the G2/M phase. Activation of caspase 3, but not caspase 8, generation of ROS, upstream of caspase-3, release of cytochrome c,increase in Bax level, and decrease in Bcl-2 level suggested the involvement of mitochondrial damage. Loss of mitochondrial transmembrane potential independent of caspase activation further suggested the mode of apoptosis. Dihydrobenzofuran-mediated cell death was absent in Bcl-xL-overexpressed cells. Overall, our results justify the role of dihydrobenzofuran lignan as potential antitumor agent, causing G2/M arrest and apoptosis involving the mitochondrial controlled pathway. These findings open promising insights as to how this specific dihydrobenzofuran lignan mediates cytotoxicity and may prove a molecular rationale for future therapeutic interventions in carcinogenesis.

A fluorinated analog of ISO-1 blocks the recognition and biological function of MIF and is orally efficacious in a murine model of colitis.

A promising therapeutic approach to diminish pathological inflammation is to inhibit the synthesis and/or biological activity of macrophage migration inhibitory factor (MIF). Prior studies have shown that intraperitoneal administration of small-molecule inhibitors targeting the catalytic pocket of MIF (e.g., ISO-1) elicits a therapeutic effect in mouse inflammation models. However, it remains to be elucidated whether these tautomerase activity inhibitors block the synthesis and/or biological activity of MIF. In this study, we investigated and compared the activity of representative MIF inhibitors from isoxazole series (fluorinated analog of ISO-1; ISO-F) and substituted quinoline series (compound 7E; 7E). Our results demonstrate that ISO-F is a more potent MIF inhibitor than 7E. Both ISO-F and 7E do not inhibit MIF synthesis but "bind-onto" MIF thereby blocking its recognition. However, in contrast to 7E, ISO-F docks well in the active site of MIF and also has a stronger binding affinity towards MIF. In line with these observations, ISO-F, but not 7E, robustly inhibits the biological function of MIF. Most importantly, ISO-F, when administered orally in a therapeutic regimen, significantly suppresses dextran sulphate sodium (DSS)-induced murine colitis. This study, which provides mechanistic insights into the anti-inflammatory efficacy of ISO-F, is the first documented report of in vivo anti-inflammatory efficacy of a MIF inhibitor upon oral administration. Moreover, the findings from this study reinforce the potential of catalytic site of MIF as a target for eliciting therapeutic effect in inflammatory disorders. Compounds (e.g., ISO-F) that block not only the recognition but also the biological function of MIF are potentially attractive for reducing pathological inflammation.

Novel caffeic acid ester derivative induces apoptosis by expressing FasL and downregulating NF-KappaB: Potentiation of cell death mediated by chemotherapeutic agents.

In the present study, we demonstrate the biological activity of esterified caffeic acid with methyl vanillate also termed as caffeic acid methyl vanillate ester (CAMVE). CAMVE potentiates TNF-induced cell death as analyzed by cell viability assay and blocks inflammatory stimuli-induced nuclear transcription factor kappaB (NF-kappaB) activation and NF-kappaB-dependent genes expression. CAMVE-mediated inhibition of NF-kappaB or induction of cell death is not cell type specific. CAMVE inhibits cell proliferation by inhibiting G1 to S phase progression. It suppresses TNF-induced Bcl-2 expression and potentiates chemotherapeutic agents-mediated cell death. CAMVE enhances intracellular free Ca(2+) and thereby activates calcineurin. Calcineurin, in turns, activates nuclear transcription factor NF-AT and its dependent genes such as FasL, which induces cell death. The data demonstrate that CAMVE is one of the combinatorial products, which is able to inhibit NF-kappaB regulated genes and cell proliferation. The combinatorial synthesis of novel caffeic ester derivatives can be a useful approach to generate potent chemotherapeutic agents and designing CAMVE as potent therapeutic agent for combination therapy may be useful to treat tumors.

Downregulation of inflammatory responses by novel caffeic acid ester derivative by inhibiting NF-kappa B.

INTRODUCTION: Considering anti-tumorigenic activity of caffeic acid phenyl ester, synthesis of several esterified form of caffeic acid is a novel approach in designing for potent drugs. RESULTS: Our study demonstrates that esterified caffeic acid with methyl vanillate, termed as caffeic acid methyl vanillate ester (CAMVE), blocked inflammatory stimuli-induced inflammatory responses. It decreased amounts of iNOS, Cox-2, and ICAM1 by inhibiting NF-kappaB through inhibition of IKK activity, I kappaB alpha degradation, and p65 nuclear translocation. CONCLUSION: Overall, our data suggest that novel caffeic acid ester down-regulates inflammatory responses through inhibition of NF-kappaB and dependent several gene expressions, further suggesting its efficacy as a promising therapeutic agent.