MitoNEET (CISD1) Knockout Mice Show Signs of Striatal Mitochondrial Dysfunction and a Parkinson's Disease Phenotype

Mitochondrial dysfunction is thought to play a significant role in neurodegeneration observed in Parkinson's disease (PD), yet the mechanisms underlying this pathology remain unclear. Here, we demonstrate that loss of mitoNEET (CISD1), an iron-sulfur containing protein that regulates mitochondrial bioenergetics, results in mitochondrial dysfunction and loss of striatal dopamine and tyrosine hydroxylase. Mitochondria isolated from mice lacking mitoNEET were dysfunctional as revealed by elevated reactive oxygen species (ROS) and reduced capacity to produce ATP. Gait analysis revealed a shortened stride length and decreased rotarod performance in knockout mice, consistent with the loss of striatal dopamine. Together, these data suggest that mitoNEET KO mice exhibit many of the characteristics of early neurodegeneration in PD and may provide a novel drug discovery platform to evaluate compounds for enhancing mitochondrial function in neurodegenerative disorders.

Structure-activity and in vivo evaluation of a novel lipoprotein lipase (LPL) activator

Elevated triglycerides (TG) contribute towards increased risk for cardiovascular disease. Lipoprotein lipase (LPL) is an enzyme that is responsible for the metabolism of core triglycerides of very-low density lipoproteins (VLDL) and chylomicrons in the vasculature. In this study, we explored the structure-activity relationships of our lead compound (C10d) that we have previously identified as an LPL agonist. We found that the cyclopropyl moiety of C10d is not absolutely necessary for LPL activity. Several substitutions were found to result in loss of LPL activity. The compound C10d was also tested in vivo for its lipid lowering activity. Mice were fed a high-fat diet (HFD) for four months, and treated for one week at 10mg/kg. At this dose, C10d exhibited in vivo biological activity as indicated by lower TG and cholesterol levels as well as reduced body fat content as determined by ECHO-MRI. Furthermore, C10d also reduced the HFD induced fat accumulation in the liver. Our study has provided insights into the structural and functional characteristics of this novel LPL activator.

Emerging strategies of targeting lipoprotein lipase for metabolic and cardiovascular diseases

Although statins and other pharmacological approaches have improved the management of lipid abnormalities, there exists a need for newer treatment modalities especially for the management of hypertriglyceridemia. Lipoprotein lipase (LPL), by promoting hydrolytic cleavage of the triglyceride core of lipoproteins, is a crucial node in the management of plasma lipid levels. Although LPL expression and activity modulation is observed as a pleiotropic action of some the commonly used lipid lowering drugs, the deliberate development of drugs targeting LPL has not occurred yet. In this review, we present the biology of LPL, highlight the LPL modulation property of currently used drugs and review the novel emerging approaches to target LPL.

Identification of small molecules that bind to the mitochondrial protein mitoNEET

MitoNEET (CISD1) is a 2Fe-2S iron-sulfur cluster protein belonging to the zinc-finger protein family. Recently mitoNEET has been shown to be a major role player in the mitochondrial function associated with metabolic type diseases such as obesity and cancers. The anti-diabetic drug pioglitazone and rosiglitazone were the first identified ligands to mitoNEET. Since little is known about structural requirements for ligand binding to mitoNEET, we screened a small set of compounds to gain insight into these requirements. We found that the thiazolidinedione (TZD) warhead as seen in rosiglitazone was not an absolutely necessity for binding to mitoNEET. These results will aid in the development of novel compounds that can be used to treat mitochondrial dysfunction seen in several diseases.

Inducible Nitric Oxide Inhibitors Block NMDA Antagonist-Stimulated Motoric Behaviors and Medial Prefrontal Cortical Glutamate Efflux

Nitric oxide (NO) plays a critical role in the motoric and glutamate releasing action of N-methyl-D-aspartate (NMDA)-antagonist stimulants. Earlier studies utilized neuronal nitric oxide synthase inhibitors (nNOS) for studying the neurobehavioral effects of non-competitive NMDA-antagonist stimulants such as dizocilpine (MK-801) and phencyclidine (PCP). This study explores the role of the inducible nitric oxide synthase inhibitors (iNOS) aminoguanidine (AG) and (-)-epigallocatechin-3-gallate (EGCG) in NMDA-antagonist induced motoric behavior and prefrontal cortical glutamate efflux. Adult male rats were administered a dose range of AG, EGCG, or vehicle prior to receiving NMDA antagonists MK-801, PCP, or a conventional psychostimulant (cocaine) and tested for motoric behavior in an open arena. Glutamate in the medial prefrontal cortex (mPFC) was measured using in vivo microdialysis after a combination of AG or EGCG prior to MK-801. Acute administration of AG or EGCG dose-dependently attenuated the locomotor and ataxic properties of MK-801 and PCP. Both AG and EGCG were unable to block the motoric effects of cocaine, indicating the acute pharmacologic action of AG and EGCG is specific to NMDA antagonism and not generalizable to all stimulant class drugs. AG and EGCG normalized MK-801-stimulated mPFC glutamate efflux. These data demonstrate that AG and EGCG attenuates NMDA antagonist-stimulated motoric behavior and cortical glutamate efflux. Our results suggest that EGCG-like polyphenol nutraceuticals (contained in “green tea” and chocolate) may be clinically useful in protecting against the adverse behavioral dissociative and cortical glutamate stimulating effects of NMDA antagonists. Medications that interfere with NMDA antagonists such as MK-801 and PCP have been proposed as treatments for schizophrenia.

Evolution of a Natural Products and Nutraceuticals Course in the Pharmacy Curriculum

Objective. To develop, implement, and modify a required, second-year pharmacy course that provides an understanding of the scientific, therapeutic, and clinical principles, as well as the evidence-based medicine underlying the use of natural products. Design. A 28-hour, multi-faculty course was developed and offered in 2008. The course was modified over the years to enhance students' practice skills in the use of natural products. A course evaluation and survey were administered to assess the students' opinions. Assessment. Students performed well in the course and provided favorable evaluations, especially for the latest offering. Students reported significantly improved skills in providing advice to patients regarding the use of natural products. Conclusion. The course increased the students' knowledge and application of information and counseling skills regarding natural products.

Clozapine underutilization in treatment-resistant schizophrenia

It has been shown that up to one third of patients with schizophrenia do not respond to antipsychotic therapy. Thus, treatment-resistant schizophrenia (TRS) remains a major mental health care challenge.

Clozapine has been shown to provide superior therapeutic benefits and is approved as first-line therapy for TRS. These benefits include improvement in both positive and negative symptoms, and reduction of suicidal behavior in patients with schizophrenia. Clozapine, however, remains significantly underused for TRS. A major reason for clozapine's underuse is its substantial adverse effect profile, mainly the risk of life-threatening agranulocytosis which necessitates regular hematologic monitoring. Another factor contributing to reduced clozapine prescribing is the increased use of other second-generation antipsychotics. In TRS patients, there is often a considerable delay in clozapine use, which is prescribed only after other unsuccessful second-generation antipsychotic trials. To combat this trend, there is a push for increased awareness to optimize clozapine prescribing. An important aspect in improving the use of clozapine therapy is physician and patient education. Furthermore, pharmacist involvement can improve clozapine prescription trends in TRS.

Black currant anthocyanins abrogate oxidative stress through Nrf2- mediated antioxidant mechanisms in a rat model of hepatocellular carcinoma

Hepatocellular carcinoma (HCC), considered to be one of the most lethal cancers with almost > 1 million deaths reported annually worldwide, remains a devastating disease with no known effective cure. Hence, chemopreventive strategies come into play, offering an effective and safe mode of treatment, ideal to ward off potential cancer risks and mortality. A major predisposing condition, pertinent to the development and progression of HCC is oxidative stress. We previously reported a striking chemopreventive effect of anthocyanin-rich black currant skin extract (BCSE) against diethylnitrosamine (DENA)-initiated hepatocarcinogenesis in rats. The current study aims to elucidate the underlying antioxidant mechanisms of black currant anthocyanins implicated in the previously observed chemopreventive effects against experimental hepatocarcinogenesis. Dietary BCSE (100 and 500 mg/kg) administered four weeks before and 18 weeks after DENA challenge decreased abnormal lipid peroxidation, protein oxidation, and expression of inducible nitric oxide synthase (iNOS) and 3-nitrotyrosine (3-NT) in a dose-responsive fashion. Mechanistic studies revealed that BCSE upregulated the gene expression of a number of hepatic antioxidant and carcinogen detoxifying enzymes, such as NAD(P)H:quinone oxidoreductase, glutathione S-transferase, and uridine diphosphate-glucuronosyltransferase isoenzymes, in DENA-initiated animals. Protein and mRNA expressions of nuclear factor E2-related factor 2 (Nrf2) were substantially elevated with BCSE treatment, providing a direct evidence of a coordinated activation of the Nrf2-regulated antioxidant pathway, which led to the upregulation of a variety of housekeeping genes. The results of our study provide substantial evidence that black currant bioactive anthocyanins exert chemopreventive actions against DENA-inflicted hepatocarcinogenesis by attenuating oxidative stress through activation of Nrf2 signaling pathway.

Angiogenesis in hepatocellular carcinoma: a potential target for chemoprevention and therapy

Hepatocellular carcinoma (HCC) remains one of the most lethal cancers in the world. Since current treatment options including surgical resection and liver transplantation offer limited therapeutic benefits, there exists a need to evaluate novel therapeutic strategies for the amelioration of HCC. Hepatic tumors are highly vascularized, possessing a rich network of blood vessels and capillaries and there exist an angiogenic component to the tumor growth observed in HCC. Thus, anti-angiogenic therapy has been suggested to possess tremendous therapeutic potential in the treatment of HCC. The process of angiogenesis involves multiple biochemical checkpoints and signaling steps, and thus providing a multitude of opportunities for therapeutic intervention. In this review, we highlight the role of angiogenesis and its use as a therapeutic strategy for HCC. The first part of the article reviews the angiogenic mechanisms with particular emphasis on the multitude of biochemical factors, such as receptors, enzymes and cytokines involved in the complex interplay of new capillary growth. Next, we present the pre-clinical studies which elucidate the anti-angiogenic effects of both dietary and non-dietary agents in animal models of HCC. Of particular interest is the examination of the effects of the antiangiogenic agents on the various angiogenic markers in the hepatic tissue of the animal challenged either with a hepatocarcinogen or xenografted with hepatic neoplastic cells. The review also highlights the clinical investigations carried out in HCC patients to evaluate the therapeutic potential of pharmacological agents with proven anti-angiogenic properties. Finally, the future directions as well as the benefits and potential challenges involved in the use of antiangiogenic pharmacotherapy in the treatment of HCC are also discussed.

Chemopreventive effect of a novel oleanane triterpenoid in a chemically induced rodent model of breast cancer

Breast cancer represents one of the most frequently diagnosed cancers and predominant causes of death in women worldwide. The value of preventive therapy to limit the devastating impact of breast cancer is well established. Various plant triterpenoids and their synthetic analogs have shown significant promise as potent chemopreventive agents in breast cancer. The current study was initiated to investigate mechanism-based chemopreventive potential of a novel synthetic oleanane triterpenoid (methyl-25-hydroxy-3-oxoolean-12-en-28-oate, AMR-Me) against 7,12-dimethylbenz(a)anthracene (DMBA)-initiated rat mammary carcinogenesis, an experimental rodent tumor model that closely resembles human mammary cancer. Rats were orally administered with AMR-Me (0.8, 1.2 and 1.6 mg/kg) three times per week for 18 weeks. Following two weeks of AMR-Me treatment, mammary carcinogenesis was initiated by oral administration of DMBA (50 mg/kg body weight). At the end of the study (16 weeks following DMBA exposure), AMR-Me exhibited a striking inhibition of DMBA-induced mammary tumor incidence, total tumor burden, average tumor weight and reversed histopathological alterations without toxicity. AMR-Me dose-dependently suppressed abnormal cell proliferation, induced apoptosis, up-regulated pro-apoptotic protein Bax and down-regulated antiapoptotic protein Bcl-2 in mammary tumors. AMR-Me upregulated the transcriptional levels of Bax, Bad, caspase-3, caspase-7 and poly(ADP-ribose) polymerase and down-regulated Bcl-2. These results clearly demonstrate for the first time that novel triterpenoid AMR-Me exerts chemopreventive efficacy in the classical DMBA model of breast cancer by suppressing abnormal cell proliferation and inducing apoptosis mediated through mitochondrial pro-apoptotic mechanisms. AMR-Me could be developed as a chemopreventive drug to reduce the risk of human breast cancer that remains a devastating disease.

Dietary phytochemicals in the chemoprevention and treatment of hepatocellular carcinoma: in vivo evidence, molecular targets, and clinical relevance

Hepatocellular carcinoma (HCC), one of the most common and lethal cancers, is a growing menace in modern society. Until recently, the majority of detected cases of liver cancer have been found in the developing nations of Asia and Africa; however, its occurrence has significantly increased in the United States. HCC occurs due to several etiologies, such as alcoholism, dietary carcinogens, iron overload, viral hepatitis, as well as several hepatic chronic diseases. In view of the limited treatment options, such as surgery and transplantation, a critical need exists to examine alternative approaches. The use of phytochemicals obtained from dietary sources provides a novel and fascinating preventive and therapeutic approach against HCC. Dietary phytochemicals possess potent antioxidant and anti-inflammatory properties which are extremely critical to combat the significant oxidative stress and inflammation implicated in liver cancer. An impressive number of phytochemicals have shown considerable promise as candidates for the prevention and treatment of HCC. In this article, we systematically review the in vivo pre-clinical evidence documenting the chemopreventive and therapeutic potential of several important dietary phytochemicals in HCC. This review critically examines the molecular mechanisms of the pharmacological effects of the aforementioned animal studies. Clinical and epidemiological studies are also highlighted in this review. Emerging issues such as bioavailability, dose optimization, targeted drug delivery, role of botanical extracts and synergy are also discussed. Finally, current challenges, limitations, future directions, innovative concepts and novel hypotheses for the use of dietary phytochemicals in the chemoprevention and amelioration of human HCC are presented.

Abstract B101: Breast cancer chemoprevention by a novel oleanane triterpenoid: Preclinical evidence

Breast cancer is the most frequently diagnosed cancer in women in both developed and developing countries. Breast cancer remains highly resistant to chemotherapy and thus a major preventive approach, such as chemoprevention, is considered an important and viable strategy in reversing the morbidity and mortality of this disease. Several plant triterpenoids, including oleananes, have exhibited significant promise as chemopreventive agents against breast cancer. Amooranin (AMR), a triterpene acid (25-hydroxy-3-oxoolean-12-en-28-oic acid) isolated from Amoora rohituka (an Indian medicinal plant), has been shown to inhibit mammary tumorigenesis both in vitro and in vivo. Methyl-25-hydroxy-3-oxoolean-12-en-28-oate (AMR-Me) is a novel synthetic AMR analog with superior antitumor effects to AMR against a panel of human breast carcinoma cells. Nevertheless, mechanism-based chemopreventive potential of AMR-Me has not been tested in an experimentally validated preclinical model of breast cancer. The objective of the present study was to investigate the chemopreventive potential and underlying mechanisms of action of AMR-Me against 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary carcinogenesis, an experimental rodent tumor model that closely resembles human mammary cancer. Rats were treated with three doses of AMR-Me (0.8, 1.2 and 1.6 mg/kg body weight) three times per week by oral gavage. Following two weeks of this treatment protocol, mammary tumorigenesis was initiated by DMBA (50 mg/kg body weight, per os). The treatment of rats with AMR-Me was continued. All animals were sacrificed 16 weeks following the DMBA exposure and the incidence and burden of mammary tumors were estimated. AMR-Me (at 1.2 or 1.6 mg/kg) displayed a striking attenuation of DMBA-induced mammary tumor incidence, total tumor burden, average tumor weight, and intratumor histopathological alterations without toxic effects. AMR-Me inhibited abnormal cell proliferation and induced apoptosis in mammary tumors. AMR-Me also upregulated the transcriptional levels of Bax, Bad, caspase-3, caspase-7 and poly (ADP-ribose) polymerase and downregulated Bcl-2. Based upon these results, we conclude that oral AMR-Me exerts a significant chemopreventive effect in DMBA-induced mammary tumorigenesis in rats through suppression of abnormal cell proliferation as well as induction of apoptosis in a dose-responsive fashion. The apoptosis-inducing effect of AMR-Me during mammary carcinogenesis may be mediated through promotion of mitochondrial pro-apoptotic mechanism. AMR-Me has considerable potential as a safe chemopreventive drug for human breast cancer that represents a dismal disease.

This study was supported by a grant (R03CA136014) from the National Cancer Institute (NCI)/National Institutes of Health (NIH). The content of this abstract is solely the responsibility of the authors and does not necessarily represent the official views of NCI or NIH.

Citation Format: Anupam Bishayee, Roslin J. Thoppil, Animesh Mandal, Altaf S. Darvesh, Deepak Bhatia. Breast cancer chemoprevention by a novel oleanane triterpenoid: Preclinical evidence. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr B101.

Alteration of hepatic proinflammatory cytokines is involved in the resveratrol-mediated chemoprevention of chemically-induced hepatocarcinogenesis

Hepatocellular carcinoma (HCC), one of the most common cancers in the world, is a leading cause of cancerrelated mortality. HCC develops most frequently in the background of oxidative stress and chronic hepatic inflammation due to viral infections, alcohol abuse as well as exposure to environmental and dietary carcinogens. As the prognosis of HCC is extremely poor and mostly unresponsive to current chemotherapeutic treatment regimens, novel preventive approaches like chemoprevention are urgently needed. We have recently found that resveratrol, a dietary polyphenol present in grapes, berries, peanuts as well as red wine, prevents diethylnitrosamine (DENA)-initiated hepatocarcinogenesis in rats through suppression of inflammation and oxidative stress. As cytokines are considered to be important mediators of inflammation, the objective of the present study was to investigate the effects of resveratrol on hepatic cytokines during DENA-initiated hepatocarcinogenesis in rats. Liver samples were harvested from our previous study in which resveratrol (50, 100 and 300 mg/kg) was found to exert a chemopreventive action against rat liver tumorigenesis induced by DENA. The levels of proinflammatory cytokines, namely tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin- 6 (IL-6), were measured using enzyme-linked immunosorbent assays. The mRNA expression of these cytokines was studied by reverse transcriptase-polymerase chain reaction for comparison. Resveratrol treatment reversed the DENAinduced alteration of the level and expression of hepatic TNF-α, IL-1β and IL-6. From the current results in conjunction with our previous findings, it can be concluded that resveratrol-mediated chemoprevention of rat liver carcinogenesis is related to alteration of proinflammatory cytokines.

Curcumin and liver cancer: a review

Primary liver cancer, also known as hepatocellular carcinoma (HCC), is one of the most lethal cancers having worldwide prevalence. Although most HCC cases are reported in the developing countries of Asia and Africa, there has been an alarming increase in HCC cases in Western Europe as well as United States. Chronic liver diseases, viral hepatitis, alcoholism as well as dietary carcinogens, such as aflatoxins and nitrosoamines, contribute to HCC. Liver transplantation as well as surgical resection at best offer limited treatment options. Thus, there exists a critical need to investigate and evaluate possible alternative chemopreventive and therapeutic strategies which may be effective in the control of liver cancer. HCC, most often, develops and progresses in a milieu of oxidative stress and inflammation. Phytochemicals, such as dietary polyphenols endowed with potent antioxidant as well as anti-inflammatory properties, provide a suitable alternative in affording alleviation of HCC. Curcumin, the principal polyphenolic curcuminoid, obtained from the turmeric rhizome Curcuma longa has long been used to cure several chronic ailments, such as neoplastic and neurodegenerative diseases. Studies suggest that curcumin may have antitumor, antioxidant, and anti-inflammatory properties. This article reviews the effects of curcumin in preclinical in vitro and in vivo models of HCC with particular emphasis to its antioxidant, apoptotic and anti-inflammatory effects as well as involvement in various molecular signaling mechanisms. This review also discusses potential challenges involved in the use of curcumin in HCC, such as bioavailability, pharmacokinetics, drug delivery as well as paucity of clinical studies.

Dimebon attenuates methamphetamine, but not MPTP, striatal dopamine depletion

Dimebon is an anti-histamine with central nervous system activity. In this report the effects of dimebon as a neuroprotectant in animal models of Parkinson's disease were tested as assessed in methamphetamine- and MPTP-induced striatal dopaminergic toxicity. Dimebon (1mg/kg) administered at 30 min prior to methamphetamine (40mg/kg) significantly reduced the amount of striatal dopamine depletion in mice, without altering the initial methamphetamine-induced increase in body temperature. In contrast, dimebon at either 1 or 25mg/kg administered at 30 min prior to MPTP (35 mg/kg) was unable to prevent MPTP-induced striatal dopamine loss as determined at 7 days post-methamphetamine/MPTP. These data suggest that dimebon may be exerting a neurotoxin specific neuroprotective effect upon the striatal dopaminergic system and may serve as an important tool for discriminating the mechanistic basis of these two dopaminergic neurotoxins.

Markers associated with sex differences in methamphetamine-induced striatal dopamine neurotoxicity

Three different approaches were employed to assess various markers associated with sex differences in responses to methamphetamine (MA). Bioassay measures reveal that MA treatment results in significantly greater reductions in body weight and increases in body temperature in male mice. Protein and mRNA determinations show significant increases in Bcl-2 and PAI-1 in male mice, while females show significant increases in GFAP and decreases in IGF-1R following treatment with MA. In mice with a heterozygous mutation of their dopamine transporter (+/- DAT), only female mice show significant differences in dopamine transporter binding and mRNA and associated reductions in striatal dopamine content along with increases in MA-evoked striatal dopamine output. The identification of these sex-dependent differences in markers provides a foundation for more exhaustive evaluation of their impact upon, and treatment of, disorders/neurotoxicity of the nigrostriatal dopaminergic system and the bases for the differences that exist between females and males.

Pomegranate-mediated chemoprevention of experimental hepatocarcinogenesis involves Nrf2-regulated antioxidant mechanisms

Hepatocellular carcinoma (HCC), one of the most prevalent and lethal cancers, has shown an alarming rise in the USA. Without effective therapy for HCC, novel chemopreventive strategies may effectively circumvent the current morbidity and mortality. Oxidative stress predisposes to hepatocarcinogenesis and is the major driving force of HCC. Pomegranate, an ancient fruit, is gaining tremendous attention due to its powerful antioxidant properties. Here, we examined mechanism-based chemopreventive potential of a pomegranate emulsion (PE) against dietary carcinogen diethylnitrosamine (DENA)-induced rat hepatocarcinogenesis that mimics human HCC. PE treatment (1 or 10 g/kg), started 4 weeks prior to the DENA challenge and continued for 18 weeks thereafter, showed striking chemopreventive activity demonstrated by reduced incidence, number, multiplicity, size and volume of hepatic nodules, precursors of HCC. Both doses of PE significantly attenuated the number and area of γ-glutamyl transpeptidase-positive hepatic foci compared with the DENA control. PE also attenuated DENA-induced hepatic lipid peroxidation and protein oxidation. Mechanistic studies revealed that PE elevated gene expression of an array of hepatic antioxidant and carcinogen detoxifying enzymes in DENA-exposed animals. PE elevated protein and messenger RNA expression of the hepatic nuclear factor E2-related factor 2 (Nrf2). Our results provide substantial evidence, for the first time, that pomegranate constituents afford chemoprevention of hepatocarcinogenesis possibly through potent antioxidant activity achieved by upregulation of several housekeeping genes under the control of Nrf2 without toxicity. The outcome of this study strongly supports the development of pomegranate-derived products in the prevention and treatment of human HCC, which remains a devastating disease.

Abstract 4607: Chemoprevention of hepatocellular carcinoma with anthocyanin-rich black currant (Ribes nigrum L.) extract: in vitro and in vivo evidence

Primary liver cancer, mostly hepatocellular carcinoma (HCC), represents the fifth most common malignancy and the third most common cause of cancer-related death worldwide. Although majority of newly diagnosed cases occur in Eastern Asia as well as sub-Saharan Africa, the incidence of HCC has been increasing steadily in Western countries, including the United States. In view of the severity of the disease and the limited treatment options available, a critical need exists for novel chemopreventive strategies which reduce the current morbidity and mortality associated with HCC. Natural dietary components, including fruits and vegetables, have drawn considerable attention due to their proven ability to affect carcinogenesis. Anthocyanins, a group of phytochemicals, are known to possess anticarcinogenic properties against several cancers, demonstrating potential for cancer prevention. Black currant (Ribes nigrum L.) fruits, recently termed “superfruits”, have high anthocyanin content. This fruit is known to possess potent antioxidant and anti-inflammatory properties. Although health benefits of black currant are known, limited evidence on antitumor effects of black currant exists with virtually no information on prevention of experimental carcinogenesis. The objective of the present study was to evaluate the potential antihepatocarcinogenic effects of anthocyanin-rich black currant skin extract (BCSE) against HepG2 human liver cancer cells as well as chemically-induced rat liver tumorigenesis. BCSE exhibited a potent cytotoxic effect on HepG2 cells with half maximal inhibitory concentration of 1.35 mg/mL. Treatment of rats with BCSE (100 or 500 mg/kg), started 4 weeks prior to and continued for 18 weeks following diethylnitrosamine (DENA)-initiated hepatocarcinogenesis, dose-dependently decreased the incidence, total number, multiplicity, size, and volume of preneoplastic hepatic nodules. The antihepatocarcinogenic effect of BCSE was supported by histopathological examination of hepatic sections. Immunohistochemical analysis of proliferating cell nuclear antigen and DNA fragmentation revealed BCSE-mediated inhibition of abnormal cell proliferation and induction of apoptosis in DENA-induced rat liver tumorigenesis respectively. BCSE also exerted an up-regulation of Bax and down-regulation of Bcl-2 expression at the translational level compared to DENA control. The results of the present investigation reveal, for the first time, that an anthocyanin-rich extract from black currant exerts a striking chemopreventive effect against hepatocellular carcinoma by inhibiting abnormal cell proliferation and inducing apoptosis through modulation of Bax/Bcl-2 ratio. These results along with a safety profile of BCSE encourage the development of black currant bioactive constituents as chemopreventive agents for human liver cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4607. doi:10.1158/1538-7445.AM2011-4607

In vivo brain microdialysis: advances in neuropsychopharmacology and drug discovery

INTRODUCTION: Microdialysis is an important in vivo sampling technique, useful in the assay of extracellular tissue fluid. The technique has both pre-clinical and clinical applications but is most widely used in neuroscience. The in vivo microdialysis technique allows measurement of neurotransmitters such as acetycholine (ACh), the biogenic amines including dopamine (DA), norepinephrine (NE) and serotonin (5-HT), amino acids such as glutamate (Glu) and gamma aminobutyric acid (GABA), as well as the metabolites of the aforementioned neurotransmitters, and neuropeptides in neuronal extracellular fluid in discrete brain regions of laboratory animals such as rodents and non-human primates. AREAS COVERED: In this review we present a brief overview of the principles and procedures related to in vivo microdialysis and detail the use of this technique in the pre-clinical measurement of drugs designed to be used in the treatment of chemical addiction, neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and as well as psychiatric disorders such as attention-deficit/hyperactivity disorder (ADHD) and schizophrenia. This review offers insight into the tremendous utility and versatility of this technique in pursuing neuropharmacological investigations as well its significant potential in rational drug discovery. EXPERT OPINION: In vivo microdialysis is an extremely versatile technique, routinely used in the neuropharmacological investigation of drugs used for the treatment of neurological disorders. This technique has been a boon in the elucidation of the neurochemical profile and mechanism of action of several classes of drugs especially their effects on neurotransmitter systems. The exploitation and development of this technique for drug discovery in the near future will enable investigational new drug candidates to be rapidly moved into the clinical trial stages and to market thus providing new successful therapies for neurological diseases that are currently in demand.

Anthocyanin-rich black currant extract suppresses the growth of human hepatocellular carcinoma cells

Dietary antioxidants, such as anthocyanins, are helpful in the prevention and control of various diseases by counteracting the imbalance of oxidative and antioxidative factors in the living systems. Black currant (Ribes nigrum L., Grossulariaceae) is known to contain high amounts of anthocyanins (250 mg/100 g fresh fruit). Black currant fruits have been used in Asian and European traditional medicine for the treatment of a variety of diseases. Black currant extract has recently been found to be the second most effective amongst nine different berry extracts studied for their free radical scavenging activity. Constituents present in black currant juice have been found to exert a number of health-promoting effects, including immunomodulatory, antimicrobial and antiinflammatory actions, inhibition of low-density lipoprotein, and reduction of cardiovascular diseases. Although antioxidant and antiinflammatory effects of black currant juice could be of value in preventing and treating oxidative stress- and inflammation-driven cancers, no experimental evidence is available to now. The objective of the present study was to evaluate the potential antiproliferative effects of black currant fruit skin extract against HepG2 human liver cancer cells. The aqueous extract yielded an anthocyanin-rich fraction with cyanidin-3-O-rutinoside as one of the major anthocyanins. This fraction exhibited a potent cytotoxic effect on HepG2 cells and this effect was more pronounced than that of delphinidin and cyanidin, two major aglycones of anthocyanins present in black currant. Our results indicate, for the first time, that black currant skin containing an anthocyanin-rich fraction inhibits the proliferation of liver cancer cells, possibly due to additive as well as synergistic effects. This product could be useful in the prevention and treatment of human hepatocellular carcinoma.

Resveratrol and liver disease: from bench to bedside and community

Liver diseases incorporate several maladies, which can range from benign histological changes to serious life-threatening conditions. These may include inborn metabolic disease, primary and metastatic cancers, alcoholic cirrhosis, viral hepatitis and drug-induced hepatotoxicity. Liver disease remains a major cause of morbidity and mortality with significant economic and social costs. Several novel approaches are currently being studied which may provide a better therapeutic outcome. The use of naturally occurring phytochemicals, some of them obtained from dietary sources, in the amelioration of illness have recently gained considerable popularity. These agents, having anti-oxidant and anti-inflammatory properties, provide a safe and effective means of ameliorating chronic disease. Resveratrol, a grape polyphenol, has shown considerable promise as a therapeutic agent in the treatment of the aforementioned liver ailments. Several studies have highlighted the hepatoprotective properties of resveratrol. Resveratrol has been shown to prevent hepatic damage because of free radicals and inflammatory cytokines, induce anti-oxidant enzymes and elevate glutathione content. Resveratrol has also been shown to modulate varied signal transduction pathways implicated in liver diseases. This review critically examines the current preclinical in vitro and in vivo studies on the preventive and therapeutic effects of resveratrol in liver diseases. The review highlights the pharmacological mechanisms involved in mediating the aforementioned effects. Toxicity, pharmacokinetics and clinical bioavailability of resveratrol are also reviewed in this article. The challenges involved, future directions and novel approaches such as site-specific drug delivery in the use of resveratrol for the prevention and treatment of liver disease are also discussed.

Identification of novel monoamine oxidase B inhibitors by structure-based virtual screening

Parkinson's disease is a severe debilitating neurodegenerative disorder. Recently, it was shown that the peroxisome proliferating-activator receptor-gamma agonist pioglitazone protected mice from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine neurotoxicity due to its ability to inhibit monoamine oxidase B (MAO-B). Docking studies were initiated to investigate pioglitazone's interactions within the substrate cavity of MAO-B. Modeling studies indicated that the thiazolidinedione (TZD) moiety was a likely candidate for its specificity to MAO-B. To explore this potential novel MAO-B scaffold, we performed a structure-based virtual screen to identify additional MAO-B inhibitors. Our search identified eight novel compounds containing the TZD-moiety that allowed for a limited study to identify structural requirements for binding to MAO-B. Inhibition assays identified two TZDs (A6355 and L136662) which were found to inhibit recombinant human MAO-B with IC(50) values of 82 and 195 nM, respectively.

Resveratrol suppresses oxidative stress and inflammatory response in diethylnitrosamine-initiated rat hepatocarcinogenesis

Hepatocellular carcinoma (HCC), one of the most frequent and deadliest cancers, has been increasing considerably in the United States. In the absence of a proven effective therapy for HCC, novel chemopreventive strategies are urgently needed to lower the current morbidity and mortality of HCC. Recently, we have reported that resveratrol, a compound present in grapes and red wine, significantly prevents diethylnitrosamine (DENA)-induced liver tumorigenesis in rats, although the mechanism of action is not completely understood. In the present study, we have examined the underlying mechanisms of resveratrol chemoprevention of hepatocarcinogenesis by investigating the effects of resveratrol on oxidative damage and inflammatory markers during DENA-initiated rat liver carcinogenesis. There was a significant increase in hepatic lipid peroxidation and protein oxidation in carcinogen control animals compared with their normal counterparts at the end of the study (20 weeks). Elevated expressions of inducible nitric oxide synthase and 3-nitrotyrosine were noticed in the livers of the same animals. Dietary resveratrol (50-300 mg/kg) administered throughout the study reversed all the aforementioned markers in a dose-responsive fashion in rats challenged with DENA. Resveratrol also elevated the protein and mRNA expression of hepatic nuclear factor E2-related factor 2 (Nrf2). Results of the present investigation provide evidence that attenuation of oxidative stress and suppression of inflammatory response mediated by Nrf2 could be implicated, at least in part, in the chemopreventive effects of this dietary agent against chemically induced hepatic tumorigenesis in rats. The outcome of this study may benefit the development of resveratrol in the prevention and intervention of human HCC.

Resveratrol in the chemoprevention and treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers and lethal diseases in the world. Although the majority of HCC cases occur in developing countries of Asia and Africa, the prevalence of liver cancer has risen considerably in Japan, Western Europe as well as the United States. HCC most commonly develops in patients with chronic liver disease, the etiology of which includes viral hepatitis (B and C), alcohol, obesity, iron overload and dietary carcinogens, including aflatoxins and nitrosamines. The current treatment modalities, including surgical resection and liver transplantation, have been found to be mostly ineffective. Hence, there is an obvious critical need to develop alternative strategies for the chemoprevention and treatment of HCC. Oxidative stress as well as inflammation has been implicated in the development and progression of hepatic neoplasia. Using naturally occurring phytochemicals and dietary compounds endowed with potent antioxidant and antiinflammatory properties is a novel approach to prevent and control HCC. One such compound, resveratrol, present in grapes, berries, peanuts as well as red wine, has emerged as a promising molecule that inhibits carcinogenesis with a pleiotropic mode of action. This review examines the current knowledge on mechanism-based in vitro and in vivo studies on the chemopreventive and chemotherapeutic potential of resveratrol in liver cancer. Pre-clinical and clinical toxicity studies as well as pharmacokinetic data of resveratrol have also been highlighted in this review. Future directions and challenges involved in the use of resveratrol for the prevention and treatment of HCC are also discussed.

Evidence for a role of energy dysregulation in the MDMA-induced depletion of brain 5-HT

Although the exact mechanism involved in the long-term depletion of brain serotonin (5-HT) produced by substituted amphetamines is not completely known, evidence suggests that oxidative and/or bioenergetic stress may contribute to 3,4-methylenedioxymethamphetamine (MDMA)-induced 5-HT toxicity. In the present study, the effect of supplementing energy substrates was examined on the long-term depletion of striatal 5-HT and dopamine produced by the local perfusion of MDMA (100 microM) and malonate (100 mM) and the depletion of striatal and hippocampal 5-HT concentrations produced by the systemic administration of MDMA (10 mg/kg i.p. x4). The effect of systemic administration of MDMA on ATP levels in the striatum and hippocampus also was examined. Reverse dialysis of MDMA and malonate directly into the striatum resulted in a 55-70% reduction in striatal concentrations of 5-HT and dopamine, and these reductions were significantly attenuated when MDMA and malonate were co-perfused with nicotinamide (1 mM). Perfusion of nicotinamide or ubiquinone (100 microM) also attenuated the depletion of 5-HT in the striatum and hippocampus produced by the systemic administration of MDMA. Finally, the systemic administration of MDMA produced a 30% decrease in the concentration of ATP in the striatum and hippocampus. These results support the conclusion that MDMA produces a dysregulation of energy metabolism which contributes to the mechanism of MDMA-induced 5-HT neurotoxicity.

Evidence for the Involvement of Nitric Oxide in 3,4-Methylenedioxymethamphetamine-Induced Serotonin Depletion in the Rat Brain

Production of reactive oxygen and/or nitrogen species has been thought to contribute to the long-term depletion of brain dopamine and serotonin (5-HT) produced by amphetamine derivatives, i.e., methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA). In the present study, the effects of nitric-oxide synthase (NOS) inhibitors were examined on the long-term depletion of striatal dopamine and/or 5-HT produced by the local perfusion of malonate and MDMA or the systemic administration of MDMA. The effect of MDMA on nitric oxide formation and nitrotyrosine concentration also was determined. Perfusion with MDMA and malonate resulted in a 34% reduction of 5-HT and 49% reduction of dopamine concentrations in the striatum. The systemic administration of NOS inhibitors, N(omega)-nitro-l-arginine methyl ester hydrochloride and S-methyl-l-thiocitrulline (S-MTC), and the peroxynitrite decomposition catalyst Fe(III) tetrakis (1-methyl-4-pyridyl) porphyrin pentachloride attenuated the MDMA- and malonate-induced depletion of striatal dopamine and 5-HT. S-MTC also attenuated the depletion of 5-HT in the striatum produced by the systemic administration of MDMA without attenuating MDMA-induced hyperthermia. Additionally, the systemic administration of MDMA significantly increased the formation of nitric oxide and the nitrotyrosine concentration in the striatum. These results support the conclusion that MDMA produces reactive nitrogen species in the rat that contribute to the neurotoxicity of this amphetamine analog.

The relationship between hyperthermia and glycogenolysis in 3,4-methylenedioxymethamphetamine-induced serotonin depletion in rats

Although the exact mechanisms involved in the serotonergic neurotoxicity produced by substituted amphetamines are not completely known, evidence suggests that oxidative and/or bioenergetic stress may contribute in the mechanism of neurotoxicity of 3,4-methylenedioxymethamphetamine (MDMA). It has been postulated that MDMA-induced hyperthermia also contributes to the MDMA-induced neurotoxicity. MDMA produces brain glycogenolysis, and MDMA-induced hyperthermia appears to mediate this effect. The relationship of MDMA-induced hyperthermia and glycogenolysis in the serotonergic neurotoxicity of MDMA was investigated in the present study. The administration of MDMA (20 mg/kg sc) at an ambient temperature of 24 degrees C produced hyperthermia and brain glycogenolysis in Postnatal Day (PND)21 and PND70 rats; however, long-term reductions in serotonin (5-HT) concentrations in the striatum were detected only in the PND70 rats. Treatment of PND21 and PND70 rats with MDMA at 17 degrees C resulted in neither hyperthermia nor glycogenolysis; nevertheless, long-term reductions in 5-HT concentrations were still evident in the PND70 rats treated with MDMA. These results support the conclusion that hyperthermia, as well as glycogenolysis, are neither necessary nor sufficient in the serotonergic neurotoxicity of MDMA.

Activation of 5-HT2 receptors induces glycogenolysis in the rat brain

The effect of 5-HT(2) receptor activation on brain glycogen and the extracellular concentration of glucose was investigated in the present study. An injection of 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) (2 mg/kg, i.p.) or mescaline (10 mg/kg, i.p.) at an ambient temperature of 29 degrees C produced a 35-45% decrease in brain glycogen that persisted for at least 2 h. DOI also increased the extracellular concentration of glucose in the striatum by 60%. Maintenance of rats at 22 degrees C significantly attenuated DOI-induced glycogenolysis, as well as DOI-induced hyperthermia, and the increase in the extracellular concentration of glucose in the striatum. DOI-induced hyperthermia, glycogenolysis and increase in the extracellular concentration of glucose also were attenuated in rats treated with the 5-HT(2) receptor antagonist, 6-methyl-1-(methylethyl)-ergoline-8beta-carboxylic acid 2-hydroxy-1-methylpropyl ester maleate (LY-53,857) (3 mg/kg, ip). These results support the conclusion that 5-HT(2) receptor activation promotes glycogenolysis and that hyperthermia exerts a prominent role in this process.

3,4-Methylenedioxymethamphetamine produces glycogenolysis and increases the extracellular concentration of glucose in the rat brain

Oxidative and/or bioenergetic stress is thought to contribute to the mechanism of neurotoxicity of amphetamine derivatives, e.g., 3,4-methylenedioxymethamphetamine (MDMA). In the present study, the effect of MDMA on brain energy regulation was investigated by examining the effect of MDMA on brain glycogen and glucose. A single injection of MDMA (10-40 mg/kg, s.c.) produced a dose-dependent decrease (40%) in brain glycogen, which persisted for at least 1 h. MDMA (10 and 40 mg/kg, s.c.) also produced a significant and sustained increase in the extracellular concentration of glucose in the striatum. Subjecting rats to a cool ambient temperature of 17 degrees C significantly attenuated MDMA-induced hyperthermia and glycogenolysis. MDMA-induced glycogenolysis also was prevented by treatment of rats with the 5-hydroxytryptamine(2) (5-HT(2)) antagonists 6-methyl-1-(1-methylethyl)-ergoline-8 beta-carboxylic acid 2-hydroxy-1 methylprophyl ester maleate (LY-53,857; 3 mg/kg i.p.), desipramine (10 mg/kg i.p.), and iprindole (10 mg/kg i.p.). LY-53,857 also attenuated the MDMA-induced increase in the extracellular concentration of glucose as well as MDMA-induced hyperthermia. Amphetamine analogs (e.g., methamphetamine and parachloroamphetamine) that produce hyperthermia also produced glycogenolysis, whereas fenfluramine, which does not produce hyperthermia, did not alter brain glycogen content. These results support the conclusion that MDMA induces glycogenolysis and that the process involves 5-HT(2) receptor activation. These results are supportive of the view that MDMA promotes energy dysregulation and that hyperthermia may play an important role in MDMA-induced alterations in cellular energetics.