Bhimanna Kuppast

Sarcophine-Diol, a Skin Cancer Chemopreventive Agent, Inhibits Proliferation and Stimulates Apoptosis in Mouse Melanoma B16F10 Cell Line

Sarcodiol (SD) is a semi-synthetic derivative of sarcophine, a marine natural product. In our previous work, we reported the significant chemopreventive effects of SD against non-melanoma skin cancer both in vitro and in vivo mouse models. In this investigation, we extended this work to study the effect of sarcodiol on melanoma development, the more deadly form of skin cancer, using the mouse melanoma B16F10 cell line. In this study we report that SD inhibits the de novo DNA synthesis and enhances fragmentation of DNA. We also evaluated the antitumor effect of SD on melanoma cell viability using several biomarkers for cell proliferation and apoptosis. SD inhibits the expression levels of signal transducers and activators of transcription protein (STAT-3) and cyclin D1, an activator of cyclin-dependent kinase 4 (Cdk4). SD treatment also enhances cellular level of tumor suppressor protein 53 (p53) and stimulates cleavage of the nuclear poly (ADP-ribose) polymerase (cleaved-PARP). SD also enhances cellular levels of cleaved Caspase-3, -8, -9 and stimulates enzymatic activities of Caspase-3, -8 and -9. These results, in addition to inhibition of cell viability, suggest that SD inhibits melanoma cell proliferation by arresting the cell-division cycle in a Go quiescent phase and activates programmed cell death (apoptosis) via extrinsic and intrinsic pathways. Finally, these studies demonstrate that SD shows a very promising chemopreventive effect in melanoma B16F10 tumor cells.

Thiazolo[4,5-d]pyrimidines as a privileged scaffold in drug discovery

Thiazolo[4,5-d]pyrimidines are fused heterocyclic ring-systems that can be viewed at the first glance as purine isosteres. They are the 7 thia-analogs of purines via the replacement of the nitrogen at position 7 of the purine ring by a sulfur atom. Because of the structural resemblance to adenine and guanine and their related derivatives as adenosine, guanosine, cAMP, cGMP and similar biomolecules, many thiazolo[4,5-d]pyrimidines scaffold were developed and utilized by medicinal chemists to design novel therapeutics. Many were found to have a broad range of pharmacological activities. The outstanding development of thiazolo[4,5-d]pyrimidines within a short time span shows its magnitude of usefulness for medicinal chemistry research. Despite their importance from pharmacological and synthetic point of views, hardly there is a comprehensive review of thiazolo[4,5-d]pyrimidines applications in medicinal research to date. Thus, this review article describes the structures and medicinal significance of all classes of thiazolo[4,5-d]pyrimidines reported in literature to date. It describe the development of thiazolo[4,5-d]pyrimidines as immune-modulators, Corticotropin Releasing Factor (CRF) receptor antagonists, anti-Parkinsons, antiviral, anticancer, antibacterial, antifungal, analgesic, anti-inflammatory agents including COX inhibitors, chemokines antagonists and Fractlkine receptor antagonists.

4-aminoquinolines: An Overview of Antimalarial Chemotherapy

Malaria is a major health problem and Plasmodium falciparum strain resistance to existing antimalarials drugs made the current approach inadequate for treatment of malaria. Drug development directed against malaria is generally targeting blood schizonts. However, to prevent relapse, tissue schizontocides are recommended to clean residual infection in the tissues. In spite of the available drugs, malarial chemotherapy is still insufficient and therefore new strategies are being explored to fill the gaps. The new approaches are being used to generate new compounds as well as combinations of drugs for development of effective and safe antimalarial therapy. This review discusses the recent developments in 4-aminoquinoline derived new analogs and insight into design and development of new antimalarials.

Synthesis of substituted pyrimidines as corticotropin releasing factor (CRF) receptor ligands

Corticotropin releasing factor (CRF) is a neuropeptide hormone produced from the hypothalamus that controls the secretion of corticotropin (ACTH) from the anterior pituitary gland that, in turn, prompts the adrenal glands to secrete glucocorticoids. This involvement in the hypothalamic-pituitary-adrenal axis (HPA) in response to stress and also playing a key role in behavioral, cardiovascular, immune and gastrointestinal systems made CRF binding to its receptors an important target in drug discovery aiming to develop lead compounds with the potential to treat various stress-related disorders including depression, anxiety and addictive disorders. Several non-peptide CRF1 receptor antagonists were developed by pharmaceutical companies and are currently in clinical trials with the aim of improving the health consequences of chronic stress and for use in the clinical management of anxiety and stress. Many showed promising results not only in treatment of anxiety and depression but also in treatment of CRF-induced hypertension, as well as in treatment of arthritis, irritable bowel syndrome and peptic ulcers. In this manuscript, we describe the synthesis of substituted pyrimidines with close structural similarities to reported lead compounds with promising CRF1 receptor affinities and carrying groups known to be associated with optimum affinity to CRF1 receptors. The affinity of the newly prepared compounds in comparison to antalarmin, a potent CRF1 receptor antagonist in clinical trials as a standard, is also described. Four compounds from the new series showed promising CRF1 receptor affinity.

Pathogen-mimicking vaccine delivery system designed with a bioactive polymer (inulin acetate) for robust humoral and cellular immune responses

Abstract New and improved vaccines are needed against challenging diseases such as malaria, tuberculosis, Ebola, influenza, AIDS, and cancer. The majority of existing vaccine adjuvants lack the ability to significantly stimulate the cellular immune response, which is required to prevent the aforementioned diseases. This study designed a novel particulate based pathogen‐mimicking vaccine delivery system (PMVDS) to target antigen‐presenting‐cells (APCs) such as dendritic cells. The uniqueness of PMVDS is that the polymer used to prepare the delivery system, Inulin Acetate (InAc), activates the innate immune system. InAc was synthesized from the plant polysaccharide, inulin. PMVDS provided improved and persistent antigen delivery to APCs as an efficient vaccine delivery system, and simultaneously, activated Toll‐Like Receptor‐4 (TLR‐4) on APCs to release chemokines/cytokines as an immune‐adjuvant. Through this dual mechanism, PMVDS robustly stimulated both the humoral (>32 times of IgG1 levels vs alum) and the cell‐mediated immune responses against the encapsulated antigen (ovalbumin) in mice. More importantly, PMVDS stimulated both cytotoxic T cells and natural killer cells of cell‐mediated immunity to provide tumor (B16‐ova‐Melanoma) protection in around 40% of vaccinated mice and significantly delayed tumor progression in rest of the mice. PMVDS is a unique bio‐active vaccine delivery technology with broader applications for vaccines against cancer and several intracellular pathogens, where both humoral and cellular immune responses are desired. Graphical abstract The PMVDS is a pathogen‐mimicking, immune‐active (TLR‐4 agonist) vaccine delivery system that provides strong antibody and cell‐mediated immune responses against encapsulated antigens for efficient cancer immunotherapy. Figure. No Caption available.

Synthesis of New Thiazolo[4,5-d]pyrimidines as Corticotropin Releasing Factor Modulators

Corticotropin-releasing factor (CRF) is a neurohormone that plays a crucial role in integrating the body’s overall response to stress. It appears necessary and sufficient for the organism to mount functional, physiological and endocrine responses to stressors. CRF is released in response to various triggers such as chronic stress. The role of CRF and its involvement in these neurological disorders suggest that new drugs that can target the CRF function or bind to its receptors may represent a new development of neuropsychiatric medicines to treat various stress-related disorders including depression, anxiety and addictive disorders. Based on pharmacophore of the CRF1 receptor antagonists, a new series of thiazolo[4,5-d] pyrimidines were synthesized as Corticotropin-releasing factor (CRF) receptor modulators and the prepared compounds carry groups shown to produce optimum binding affinity to CRF receptors. Twenty two compounds were evaluated for their CRF1 receptor binding affinity in HEK 293 cell lines and two compounds 5o and 5s showed approximately 25% binding affinity to CRF1 receptors. Selected compounds (5c and 5f) were also evaluated for their effect on expression of genes associated with depression and anxiety disorders such as CRF1, CREB, MAO-A, SERT, NPY, DatSLC6a3, and DBH and significant upregulation of CRF1 mRNA has been observed with compound 5c.

The "homeostasis hormone" and its CRF1 receptor. From structure to function

Address for correspondence: Liapakis George, Department of Pharmacology, Faculty of Medicine, University of Crete, Voutes, Heraklion, 71003, Crete, Greece, Tel.: 30-281-0394-525, Fax: 30-281-0394-530, e-mail: liapakis@med.uoc.gr Fahmy Hesham, Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007, USA, Tel.: +1-605-688-4243, Fax: +1605-688-5993, e-mail: hesham.fahmy@sdstate.edu Received 18-03-12, Revised 20-04-12, Accepted 03-05-12

Synthesis of 2-imino and 2-hydrazono thiazolo[4,5-d]pyrimidines as corticotropin releasing factor (CRF) antagonists

Corticotropin-releasing factor (CRF) is an important neuropeptide hormone which controls the bodys overall response to stress. It plays a crucial role in regulating the behavioral, cardiovascular, immune and gastrointestinal systems. Over-activation of the CRF system has been implicated in many disorders including anxiety, depression, drug addiction, hypertension, Irritable Bowel Syndrome (IBS), peptic ulcers, inflammation and others. Thus, binding of CRF to its receptors is an attractive target to develop new medications which aim at treating ailments associated with chronic stress. Numerous small-molecule non-peptide CRF receptor antagonists were developed and many are in various stages in clinical trials. Many showed great promise in treatment of anxiety, depression, peptic ulcers, inflammation, IBS and drug addiction. In our recent previous work, the development of two series of pyrimidine and fused pyrimidine CRF antagonists were described. In continuation of our efforts in this direction, in the current manuscript, the synthesis of a third series of CRF receptor antagonists is described. The binding affinities of select compounds for the type 1 receptor of CRF (CRF1R) were determined and compared to a standard CRF antagonist drug antalarmin. A lead compound was identified and further evaluated by measuring its effect on the inhibition of the agonist-stimulated accumulation of second messengers.

Structure and Function of Small Non-Peptide CRF Antagonists and their Potential Clinical Use

Corticotropin-releasing factor (CRF) can be considered a very important hormone or a chemical mediator. It works closely with other systems to regulate the manner through which the body may respond to stress. Thus it affects many biological processes associated with stress. Dysfunction of this system has also been correlated with various diseases such as major depression, anxiety, drug addiction and eating disorders. Rationally, this means that interfering with binding of CRF to its intended receptors can be an attractive target for drug design aiming at developing new medications for many ailments that are associated with stress such as depression, anxiety and stress-induced relapse in drug addiction. Hundreds of accounts of small molecule antagonists have appeared in the literature and the preclinical and clinical pharmacology have been reported for many of these agents. Several classes of small molecule CRF receptor antagonists which belong to the non-peptide class have been developed with many being widely used for research purposes. Currently several major pharmaceutical companies are pursuing development of small non-peptide CRF1 receptor antagonists. In this review article we explain the importance of development of non-peptide CRF antagonists and their clinical relevance with emphasis on those members that showed great promise or those that were advanced to clinical trials.

Abstract 479: The effects of sarcophine-diol (SD) on melanoma B16F10 cell line

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Sarcophine diol (SD) is a non-toxic semi-synthetic derivative of sarcophine, a marine natural product. Previously, we studied the chemopreventive effects of SD on non-melanoma tumor development using both animal and cellular models. In this current study, we used the mouse melanoma B16F10 cell line to investigate the possible effects of SD on melanoma cell development. We found that SD at a 250 µM concentrations inhibits cell duplication. Melanoma cells treated with SD do not form the contractile ring, a multi-protein complex involved in cell division. As a result of cytoskeleton modification, cells treated with SD do not show the ability to carry out de novo synthesis of DNA, and their DNA show a high degree of fragmentation compared to untreated controls. To explore the molecular mechanism(s) involved in the disassembly of the contractile machinery, our studies show that SD treatment inhibits cell membrane permeability for small molecular mass compounds (e.g. ethidium bromide which is used as an indicator for cell permeability to Ca2+ ions). These findings are consistent with the observation that SD increases cleavage of phospholipase A2 (PLA2), resulting in low PLA2 enzymatic activity. These findings are also consistent with the observation that SD, in a time- and concentration-dependent manner, inhibits the expression level of the cyclooxygenase-2 (Cox-2). As a result of the decline in membrane permeability in SD treated cells and the negative effect of SD on the protein level of phospholipase C (PLC), which both affect the activity of contractile machinery, the non-dividing cells undergo apoptosis. The latter notion is supported by findings that SD inhibits the expression of STAT-3 (signal transducer and activator of transcription protein), and cyclin D1 (an activator of cyclin-dependent kinase 4, Cdk4). SD treatment also enhances the cellular level of the tumor suppressing protein 53 (p53) and stimulates cleavage of the nuclear poly(ADP-ribose) polymerase (cleaved-PARP). SD also enhances the cellular level of cleaved-Caspase-3, -8, -9 and stimulates enzymatic activities of Caspase-3, -8 and -9. All these findings, in addition to inhibition of cell viability, suggest that SD most likely inhibits melanoma cell growth by arresting the cell-division cycle in a Go quiescent phase and simultaneously activates apoptosis via extrinsic and intrinsic pathways. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 479. doi:1538-7445.AM2012-479