Evaluation of a GSH-targeting prodrug via a sulfonamide-induced "integrative" platform for selective cancer therapy.

A sulfonamide-appended gemcitabine prodrug was newly produced. The prodrug was shown to efficiently distinguish GSH from cysteine and homocysteine. Upon reaction of this prodrug with GSH, which is relatively abundant in tumor cells, sulfonyl group cleavage occurred as well as active release of the drug GMC and a concomitant increase in the innate fluorescence intensity. As a proof of concept, colocalization experiments were carried out; these experiments demonstrated that the probe LHX resulted in, via receptor-mediated endocytosis, significantly improved therapeutic efficacy and few side effects. Thus, these results indicated the theranostic agent to be a promising "integrative" platform for efficient cancer therapy. The agent can be activated in real time, and not only be selectively monitored and localized by specific tumour cells, but also undergo cascaded cleavage to induce both a fluorogenic response and release of an active cytotoxic drug.

Preclinical toxicity evaluation of JD5037, a peripherally restricted CB1 receptor inverse agonist, in rats and dogs for treatment of nonalcoholic steatohepatitis.

JD5037 is a novel peripherally restricted CB1 receptor (CB1R) inverse agonist being developed for the treatment of visceral obesity and its metabolic complications, including nonalcoholic fatty liver disease and dyslipidemia. JD5037 was administered by oral gavage at 10, 40, and 150 mg/kg/day dose levels for up to 34 days to Sprague Dawley rats, and at 5, 20, and 75 mg/kg/day dose levels for 28 consecutive days to Beagle dogs. In rats, higher incidences of stereotypic behaviors were observed in 10 mg/kg females and 40 mg/kg males, and slower responses for reflex and sensory tests were observed only in males at 10 and 40 mg/kg during neurobehavioral testing. Sporadic minimal incidences of decreased activity (males) and seizures (both sexes) were observed in rats during daily clinical observations, without any clear dose-relationship. Male dogs at 75 mg/kg during treatment period, but not recovery period, had an increased incidence of gut associated lymphoid tissue hyperplasia and inflammation in the intestine. In both species, highest dose resulted in lower AUCs indicative of non-linear kinetics. Free access to food increased the plasma AUC∞ by ~4.5-fold at 20 mg/kg in dogs, suggesting presence of food may help in systemic absorption of JD5037 in dogs. Based on the study results, 150 mg/kg/day in rats, and 20 and 75 mg/kg/day doses in male and female dogs, respectively, were determined to be the no-observed-adverse-effect-levels (NOAELs).

Apoptotic cell-mimicking gold nanocages loaded with LXR agonist for attenuating the progression of murine systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) constitutes an autoimmune disease characterized by the breakdown of tolerance to self-antigens, sustained production of pathogenic autoantibodies, and damage to multiple organs and tissues. Nanoparticle (NP)-based therapeutics have demonstrated efficacy in attenuating the progression of SLE. However, investigations of nano-drugs that address the crucial initiating factor in the pathogenesis of SLE; e.g., inefficient clearance of apoptotic cells by phagocytes and consequent accumulation of self-antigens, have seldom been reported. Here, an apoptotic cell-mimicking gold nanocage (AuNC)-based nano drug carrier capable of correcting the impaired clearance of apoptotic cells in SLE was rationally designed and generated by conjugating phosphatidylserine (PS) on the surface of liposome-coated AuNCs for liver X receptor (LXR) agonist T0901317 delivery. Notably, PS-lipos-AuNC@T0901317 could efficiently enhance apoptotic cell clearance by elevating the expression of Mer, one of the pivotal phagocytosis-associated receptors on macrophages, resulting in decreased production of anti-dsDNA autoantibodies, reduced inflammatory response, and alleviation of kidney damage in lupus model mice. Additionally, PS-lipos-AuNC could be tracked by photoacoustic imaging for nano drug carrier biodistribution. By addressing the crucial pathogenic factor of SLE, the NP-based delivery system in this study is envisioned to provide a promising strategy to treat this complex and challenging disease.

Evaluation of Possible Proarrhythmic Potency: Comparison of the Effect of Dofetilide, Cisapride, Sotalol, Terfenadine, and Verapamil on hERG and Native IKr Currents and on Cardiac Action Potential.

The proarrhythmic potency of drugs is usually attributed to the IKr current block. During safety pharmacology testing analysis of IKr in cardiomyocytes was replaced by human ether-a-go-go-related gene (hERG) test using automated patch-clamp systems in stable transfected cell lines. Aim of this study was to compare the effect of proarrhythmic compounds on hERG and IKr currents and on cardiac action potential. The hERG current was measured by using both automated and manual patch-clamp methods on HEK293 cells. The native ion currents (IKr, INaL, ICaL) were recorded from rabbit ventricular myocytes by manual patch-clamp technique. Action potentials in rabbit ventricular muscle and undiseased human donor hearts were studied by conventional microelectrode technique. Dofetilide, cisapride, sotalol, terfenadine, and verapamil blocked hERG channels at 37°C with an IC50 of 7 nM, 18 nM, 343 µM, 165 nM, and 214 nM, respectively. Using manual patch-clamp, the IC50 values of sotalol and terfenadine were 78 µM and 31 nM, respectively. The IC50 values calculated from IKr measurements at 37°C were 13 nM, 26 nM, 52 µM, 54 nM, and 268 nM, respectively. Cisapride, dofetilide, and sotalol excessively lengthened, terfenadine, and verapamil did not influence the action potential duration. Terfenadine significantly inhibited INaL and moderately ICaL, verapamil blocked only ICaL. Automated hERG assays may over/underestimate proarrhythmic risk. Manual patch-clamp has substantially higher sensitivity to certain drugs. Action potential studies are also required to analyze complex multichannel effects. Therefore, manual patch-clamp and action potential experiments should be a part of preclinical safety tests.

Mechanism Of Nephroprotection By Picrorhiza Kurroa.

BACKGROUND: Humans are exposed either deliberately or unintentionally to a variety of diverse chemicals that harm the kidney. To reduce the alarming high incidence of nephrotoxicity, some chemical as well as herbal alternatives are needed. Nimesulide belongs to a group of antiinflammatory drugs that are in common use in our society. Like all non-steroidal antiinflammatory drugs, it carries a potential threat of nephrotoxicity especially when other risk factors are present in user. The objective of this study was to find herbal alternative with antiinflammatory and nephroprotective qualities and to bring into light its mechanism of nephroprotection. METHODS: This experimental study was conducted on mice at National Institute of Health, Islamabad from Feb 2013 to March 2014. Nimesulide was given in a dosage of 750 mg/kg body weight for 3 days to induce nephrotoxicity and protective effect of Picrorhiza kurroa was noted in two doses of 250 mg/kg and 500 mg/kg for 14 days. Renal function tests were done and urinary PGE2 was measured to assess the effect of nimesulide and Pk on kidneys. RESULTS: In our study, significant improvement was seen in serum urea and creatinine levels in mice receiving low and high dose Picrorhiza kurroa. However, no significant improvement was noted in urinary PGE2 showing that the mechanism of nephroprotection is not by vasodilatory effect of Pk. CONCLUSIONS: This study showed nimesulide nephrotoxic potential and Pk is a good herbal antiinflammatory and nephroprotective alternative for nimesulide but its mechanism of nephroprotection is not by PGE2.

Influences of Chlorella vulgaris dietary supplementation on growth performance, hematology, immune response and disease resistance in Oreochromis niloticus exposed to sub-lethal concentrations of penoxsulam herbicide.

Little is known regarding the impact of penoxsulam, a fluorinated benzenesulfonamid rice herbicide, on Oreochromis niloticus (O. niloticus). Therefore, the current study was undertaken to highlight the effects of penoxsulam exposure on O. niloticus and to evaluate the advantages of Chlorella vulgaris (CV) dietary supplementation against the induced effects. The 96-h lethal concentration 50 (LC50) penoxsulam value for O. niloticus was estimated at 8.948 mg/L by probit analysis in a static bioassay experiment. Next, 360 healthy fish were randomly allocated into 6 treatment groups. The T1 group served as the negative control and was fed a basal diet. The T2 group served as the positive control and was fed a basal diet supplemented with 10% CV. The fish in the T3 and T4 groups were exposed to 1/10 the 96-h LC50 of penoxsulam (0.8948 mg/L) and were fed the basal diet alone or the basal diet supplemented with 10% CV, respectively. The fish in the T5 and T6 groups were exposed to 1/5 the 96-h LC50 of penoxsulam (1.7896 mg/L) and fed the basal diet alone or the basal diet supplemented with 10% CV, respectively. Sub-acute penoxsulam exposure significantly altered hematological indices, as well as compromised the fish's immune defense mechanisms, including the phagocytic percentage, phagocytic index, nitric oxide production, immunoglobulin M levels and lysozyme, anti-trypsin and bactericidal activities subsequently decreasing O. niloticus's resistance to the Aeromonus sobria challenge and increasing disease symptoms and the mortality rate. Furthermore, sub-chronic penoxsulam exposure markedly altered growth performance, oxidant/antioxidant status and liver status and down-regulated the expression of interleukin-1ß (IL-1ß) and tumor necrosis-α (TNF-α). Interestingly, incorporating 10% CV into the diet protects fish against sub-acute penoxsulam-induced immunotoxicity via improvement of immune responses that increases the resistance against bacterial infection. Further, it improved the growth performance, oxidant/antioxidant status, liver status and markedly up-regulated immune-related gene expression, IL-1ß and TNF-α, in the spleens of fish sub-chronically exposed to penoxsulam. These outcomes showed that dietary CV supplementation can protect the commercially valuable freshwater fish O. niloticus against penoxsulam toxicity and may be a potential feed supplement for Nile tilapia in aquaculture.

Nonclinical Safety Assessment of the γ-Secretase Inhibitor Avagacestat.

The toxicity of avagacestat, a sulfonamide-based gamma (γ)-secretase inhibitor that was in development as a treatment for Alzheimer's disease, was evaluated in a comprehensive nonclinical toxicology program that included 6-month and 1-year repeat-dose toxicity studies in rats and dogs, respectively. There was a spectrum of mechanism-based changes attributed to inhibition of Notch signaling that regulates the differentiation and proliferation of cells throughout development and in adult tissues. In both rats and dogs, ovarian follicular degeneration and atrophy and a low incidence of granulosa cell hyperplasia and benign granulosa-thecal cell tumors were observed. Gastrointestinal (GI) findings, including goblet cell metaplasia, dilatation of intestinal crypts/glands, mucosal epithelial necrosis and regeneration, and villous atrophy, were limited to dogs that had clinical evidence of GI toxicity. Other avagacestat-related findings attributed to interference with Notch signaling included decreases in peripheral lymphocytes (T and/or B cells) and lymphoid depletion in lymph nodes and the spleen in both species, as well as epiphyseal cartilage and trabecular bone changes in rats. Pharmacologically mediated decreases in brain and cerebrospinal fluid levels of ß-amyloid (Aß) peptides Aß40 and Aß42 and decreased expression of white blood cell mRNA levels of the Notch-regulated gene hairy and enhancer of split-1 confirmed target engagement at all doses. Reductions in brain Aß peptide levels (22 to 34%) in dogs after 1 year at exposures up to the no-observed-effect level for GI toxicity of 1.1× the human plasma exposure, and reversible GI changes at a 3.2× multiple, indicated that a sustained pharmacodynamic effect was attained at exposures without dose-limiting toxicity.

Identification of Atuveciclib (BAY†1143572), the First Highly Selective, Clinical PTEFb/CDK9 Inhibitor for the Treatment of Cancer.

Selective inhibition of exclusively transcription-regulating PTEFb/CDK9 is a promising new approach in cancer therapy. Starting from lead compound BAY-958, lead optimization efforts strictly focusing on kinase selectivity, physicochemical and DMPK properties finally led to the identification of the orally available clinical candidate atuveciclib (BAY 1143572). Structurally characterized by an unusual benzyl sulfoximine group, BAY 1143572 exhibited the best overall profile in vitro and in vivo, including high efficacy and good tolerability in xenograft models in mice and rats. BAY 1143572 is the first potent and highly selective PTEFb/CDK9 inhibitor to enter clinical trials for the treatment of cancer.

Proarrhythmic risk assessment using conventional and new in vitro assays.

Drug-induced QT prolongation is a major safety issue in the drug discovery process. This study was conducted to assess the electrophysiological responses of four substances using established preclinical assays usually used in regulatory studies (hERG channel or Purkinje fiber action potential) and a new assay (human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs)-field potential). After acute exposure, moxifloxacin and dofetilide concentration-dependently decreased IKr amplitude (IC50 values: 102 µM and 40 nM, respectively) and lengthened action potential (100 µM moxifloxacin: +23% and 10 nM dofetilide: +18%) and field potential (300 µM moxifloxacin: +76% and 10 nM dofetilide: +38%) durations. Dofetilide starting from 30 nM induced arrhythmia in hiPSC-CMs. Overnight application of pentamidine (10 and 100 µM) and arsenic (1 and 10 µM) decreased IKr, whereas they were devoid of effects after acute application. Long-term pentamidine incubation showed a time- and concentration-dependent effect on field potential duration. In conclusion, our data suggest that hiPSC-CMs represent a fully functional cellular electrophysiology model which may significantly improve the predictive validity of in vitro safety studies. Thereafter, lead candidates may be further investigated in patch-clamp assays for mechanistic studies on individual ionic channels or in a multicellular Purkinje fiber preparation for confirmatory studies on cardiac conduction.

Melatonin reverses H-89 induced spatial memory deficit: Involvement of oxidative stress and mitochondrial function.

Oxidative stress and mitochondrial dysfunction play indispensable role in memory and learning impairment. Growing evidences have shed light on anti-oxidative role for melatonin in memory deficit. We have previously reported that inhibition of protein kinase A by H-89 can induce memory impairment. Here, we investigated the effect of melatonin on H-89 induced spatial memory deficit and pursued their interactive consequences on oxidative stress and mitochondrial function in Morris Water Maze model. Rats received melatonin (50 and 100µg/kg/side) and H-89(10µM) intra-hippocampally 30min before each day of training. Animals were trained for 4 consecutive days, each containing one block from four trials. Oxidative stress indices, including thiobarbituric acid (TBARS), reactive oxygen species (ROS), thiol groups, and ferric reducing antioxidant power (FRAP) were assessed using spectrophotometer. Mitochondrial function was evaluated through measuring ROS production, mitochondrial membrane potential (MMP), swelling, outer membrane damage, and cytochrome c release. As expected from our previous report, H-89 remarkably impaired memory by increasing the escape latency and traveled distance. Intriguingly, H-89 significantly augmented TBARS and ROS levels, caused mitochondrial ROS production, swelling, outer membrane damage, and cytochrome c release. Moreover, H-89 lowered thiol, FRAP, and MMP values. Intriguingly, melatonin pre-treatment not only effectively hampered H-89-mediated spatial memory deficit at both doses, but also reversed the H-89 effects on mitochondrial and biochemical indices upon higher dose. Collectively, these findings highlight a protective role for melatonin against H-89-induced memory impairment and indicate that melatonin may play a therapeutic role in the treatment of oxidative- related neurodegenerative disorders.

New in vitro model for proarrhythmia safety screening: IKs inhibition potentiates the QTc prolonging effect of IKr inhibitors in isolated guinea pig hearts.

INTRODUCTION: Preclinical in vivo QT measurement as a proarrhythmia essay is expensive and not reliable enough. The aim of the present study was to develop a sensitive, cost-effective, Langendorff perfused guinea pig heart model for proarrhythmia safety screening. METHODS: Low concentrations of dofetilide and cisapride (inhibitors of the rapid delayed rectifier potassium current, IKr) were tested alone and co-perfused with HMR-1556 (inhibitor of the slow delayed rectifier potassium current, IKs) in Langendorff perfused guinea pig hearts. The electrocardiographic rate corrected QT (QTc) interval, the Tpeak-Tend interval and the beat-to-beat variability and instability (BVI) of the QT interval were determined in sinus rhythm. RESULTS: Dofetilide and HMR-1556 alone or co-perfused, prolonged the QTc interval by 20±2%, 10±1% and 55±10%, respectively. Similarly, cisapride and HMR-1556 alone or co-perfused, prolonged the QTc interval by 11±3%, 11±4% and 38±6%, respectively. Catecholamine-induced fast heart rate abolished the QTc prolonging effects of the IKr inhibitors, but augmented the QTc prolongation during IKs inhibition. None of the drug perfusions increased significantly the Tpeak-Tend interval and the sinus BVI of the QT interval. DISCUSSION: IKs inhibition increased the QTc prolonging effect of IKr inhibitors in a super-additive (synergistic) manner, and the QTc interval was superior to other proarrhythmia biomarkers measured in sinus rhythm in isolated guinea pig hearts. The effect of catecholamines on the QTc facilitated differentiation between IKr and IKs inhibitors. Thus, QTc measurement in Langendorff perfused guinea pig hearts with pharmacologically attenuated repolarization reserve and periodic catecholamine perfusion seems to be suitable for preclinical proarrhythmia screening.

Induction of mitotic and chromosomal abnormalities on Allium cepa cells by pesticides imidacloprid and sulfentrazone and the mixture of them.

To evaluate the cytotoxic and genotoxic effects of low concentrations of pesticides in non-target organisms, seeds of Allium cepa were exposed for 24 h to the imidacloprid insecticide, sulfentrazone herbicide and to the mixture of them, followed by recovery periods of 48 and 72 h. Imidacloprid results indicated an indirect genotoxic effect by inducing different types of chromosome aberration (CA), mainly bridges and chromosomal adherences. Cells with micronucleus (MN) were not significant in the analyzed meristems. Moreover, the 72-h recovery tests indicated that the two lower concentrations of the insecticide (0.036 and 0.36 g L(-1)) had their genotoxic effects minimized after discontinuation of treatment, differently to the observed for the field concentration (3.6 g L(-1)). Sulfentrazone herbicide at field concentration (6 g L(-1)) caused cytotoxic effects by inducing nuclear fragmentation and inhibition of cell division. The other concentrations (0.06, 0.6 and 1.2 g L(-1)) indicated genotoxic effects for this herbicide. The concentration of 0.06 g L(-1) induced persistent effects that could be visualized both by the induction of CA in the recovery times as by the presence of MN in meristematic and F1 cells. The induction of MN by this lowest concentration was associated with the great amount of breakage, losses and chromosomal bridges. The mixture of pesticides induced genotoxic and cytotoxic effects, by reducing the MI of the cells. The chromosomal damage induced by the mixture of pesticides was not persistent to the cells, since such damage was minimized 72 h after the interruption of the exposure.

EVALUATION OF THERAPEUTIC POTENTIAL OF PICRURHIZA KURROA GLYCOSIDAL EXTRACT AGAINST NIMESULIDE NEPHROTOXICITY: A PILOT STUDY.

BACKGROUND: Picrorhiza kurroa (Pk) is a traditional Ayurvedic herb famous as a potent bepatoprotective agent, only few studies are available on the nephroprotective activity of this herb. The objective of this pilot study was to determine the therapeutic effectiveness of Pk against nimesulide induced toxicity. METHODS: This laboratory based experimental study was conducted on mice at National Institute of Health, Islamabad from Dec 2012 to Jan 2013. The mice were divided in to 4 groups. One group was given only PK while the other three groups were given nimesulide in a dosage of 750 mg/kg body weight for 3 days to induce nephrotoxicity and protective effect of Pk was noted by giving 250 mg/kg and 500 mg/kg pk for 14 days to the two of the nimesulide induced nephrotoxicity groups. Biochemical assessment of kidney was done by measuring serum urea & creatinine. Also histology was done to confirm the findings of biochemical assessment. RESULTS: In our pilot study out of 20 mice, 19 mice survived. Only 1 mouse of nimesulide group died. Mean serum urea of nimesulide group was 60 mg/dl and was decreased to 23 mg/dI and 25 mg/dl by two doses of Pk. Mean creatinine in group 2 was 0.55 mg/dl and was decreased to 0.21 and 0.19 mg/dl by two doses of Pk. CONCLUSION: Our study shows that nimesulide is a potential nephrotoxic drug and its toxic effects on kidney can be minimized by using glycosidal extract of Pk.

Hepatoprotective effects of Yulangsan polysaccharide against nimesulide-induced liver injury in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Yulangsan polysaccharide (YLSPS) is often used in popular folk medicine in the Guangxi Zhuang Autonomous Region of China as a chief ingredient of Millettia pulchra, which is used as a hepatic protection, anti-aging and memory improving agent. AIM OF THE STUDY: This study was designed to investigate the protective effects of polysaccharides from Millettia pulchra Kurz var.laxior (Dunn) (Yulangsan polysaecharide, YLSPS) against nimesulide-induced hepatotoxicities in mice. MATERIALS AND METHODS: Liver injury was induced in mice by administering nimesulide. Simultaneously, YLSPS was administered 2h prior to the administration of nimesulide. Dimethyl diphenyl bicarboxylate (DDB) was used as a reference drug. RESULTS: Compared with the nimesulide group, YLSPS significantly decreased the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and the content of bilirubin in the serum. The anti-oxidative effect of YLSPS was observed from the increase of the superoxide dismutase (SOD) and catalase and glutathione peroxidase (GSH-Px) activities in the liver, both of which were decreased by nimesulide. Moreover, the content of malondialdehyde (MDA) was reduced, and histological findings also confirmed the anti-hepatotoxic activity. In addition, YLSPS significantly inhibited proinflammatory mediators, such as tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6). Additionally, YLSPS also enhanced the mitochondrial antioxidant and inhibited dead cells by preventing the down-regulation of Bcl-2, up-regulation and release of Bax along with caspase 9 and 3 activity, confirming the involvement of mitochondria in the nimesulide-induced apoptosis. CONCLUSION: The protective effect of YLSPS against nimesulide-induced hepatic injury may rely on its ability to reduce oxidative stress and prevent nimesulide-induced hepatotoxicity by inhibiting critical control points of apoptosis.

Dietary exposure to the endocrine disruptor tolylfluanid promotes global metabolic dysfunction in male mice.

Environmental endocrine disruptors are implicated as putative contributors to the burgeoning metabolic disease epidemic. Tolylfluanid (TF) is a commonly detected fungicide in Europe, and previous in vitro and ex vivo work has identified it as a potent endocrine disruptor with the capacity to promote adipocyte differentiation and induce adipocytic insulin resistance, effects likely resulting from activation of glucocorticoid receptor signaling. The present study extends these findings to an in vivo mouse model of dietary TF exposure. After 12 weeks of consumption of a normal chow diet supplemented with 100 parts per million TF, mice exhibited increased body weight gain and an increase in total fat mass, with a specific augmentation in visceral adipose depots. This increased adipose accumulation is proposed to occur through a reduction in lipolytic and fatty acid oxidation gene expression. Dietary TF exposure induced glucose intolerance, insulin resistance, and metabolic inflexibility, while also disrupting diurnal rhythms of energy expenditure and food consumption. Adipose tissue endocrine function was also impaired with a reduction in serum adiponectin levels. Moreover, adipocytes from TF-exposed mice exhibited reduced insulin sensitivity, an effect likely mediated through a specific down-regulation of insulin receptor substrate-1 expression, mirroring effects of ex vivo TF exposure. Finally, gene set enrichment analysis revealed an increase in adipose glucocorticoid receptor signaling with TF treatment. Taken together, these findings identify TF as a novel in vivo endocrine disruptor and obesogen in mice, with dietary exposure leading to alterations in energy homeostasis that recapitulate many features of the metabolic syndrome.

Chimeric TK-NOG mice: a predictive model for cholestatic human liver toxicity.

Due to the substantial interspecies differences in drug metabolism and disposition, drug-induced liver injury (DILI) in humans is often not predicted by studies performed in animal species. For example, a drug (bosentan) used to treat pulmonary artery hypertension caused unexpected cholestatic liver toxicity in humans, which was not predicted by preclinical toxicology studies in multiple animal species. In this study, we demonstrate that NOG mice expressing a thymidine kinase transgene (TK-NOG) with humanized livers have a humanized profile of biliary excretion of a test (cefmetazole) drug, which was shown by an in situ perfusion study to result from interspecies differences in the rate of biliary transport and in liver retention of this drug. We also found that readily detectable cholestatic liver injury develops in TK-NOG mice with humanized livers after 1 week of treatment with bosentan (160, 32, or 6 mg/kg per day by mouth), whereas liver toxicity did not develop in control mice after 1 month of treatment. The laboratory and histologic features of bosentan-induced liver toxicity in humanized mice mirrored that of human subjects. Because DILI has become a significant public health problem, drug safety could be improved if preclinical toxicology studies were performed using humanized TK-NOG.

Rapeseed oil-rich diet alters in vitro menadione and nimesulide hepatic mitochondrial toxicity.

Diet-induced changes in the lipid composition of mitochondrial membranes have been shown to influence physiological processes. However, the modulation effect of diet on mitochondrially-active drugs has not yet received the deserved attention. Our hypothesis is that modulation of membrane dynamics by diet impacts drug-effects on liver mitochondrial functioning. In a previous work, we have shown that a diet rich in rapeseed oil altered mitochondrial membrane composition and bioenergetics in Wistar rats. In the present work, we investigated the influence of the modified diet on hepatic mitochondrial activity of two drugs, menadione and nimesulide, and FCCP, a classic protonophore, was used for comparison. The results showed that the effects of menadione and nimesulide were less severe on liver mitochondria for rats fed the modified diet than on rats fed the control diet. A specific effect on complex I seemed to be involved in drug-induced mitochondria dysfunction. Liver mitochondria from the modified diet group were more susceptible to nimesulide effects on MPT induction. The present work demonstrates that diet manipulation aimed at modifying mitochondrial membrane properties alters the toxicity of mitochondria active agents. This work highlights that diet may potentiate mitochondrial pharmacologic effects or increase drug-induced liabilities.

Translational pharmacokinetic-pharmacodynamic modeling of QTc effects in dog and human.

INTRODUCTION: Preclinical assessment of the heart rate corrected QT interval (QTc) is an important component of the cardiovascular safety evaluation in drug discovery. Here we aimed to quantify the translational relationship between QTc prolongation and shortening in the conscious telemetered dog and humans by a retrospective pharmacokinetic-pharmacodynamic (PKPD) analysis. METHODS: QTc effects of 2 proprietary compounds and 2 reference drugs (moxifloxacin and dofetilide) were quantified in conscious dogs and healthy volunteers via a linear and Emax pharmacokinetic-pharmacodynamic models. The translational relationship was quantified by correlating the QTc response from dog and human at matching free drug concentrations. RESULTS: A consistent translational relationship was found at low delta-QTc intervals indicating that a QTc change of 2.5-8 ms in dog would correspond to a 10 ms change in human. DISCUSSION: The translational relationship developed here can be used to predict the QTc liability in human using preclinical dog data. It could therefore help protect the health of human volunteers, for example by appropriate clinical study design and dose selection, as well as improve future decision-making and help reduce compound attrition due to changes in QT interval.

Synthesis and characterization of celecoxib derivatives as possible anti-inflammatory, analgesic, antioxidant, anticancer and anti-HCV agents.

A series of novel N-(3-substituted aryl/alkyl-4-oxo-1,3-thiazolidin-2-ylidene)-4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamides 2a-e were synthesized by the addition of ethyl a-bromoacetate and anhydrous sodium acetate in dry ethanol to N-(substituted aryl/alkylcarbamothioyl)-4-[5-(4-methylphenyl)-3-(trifluoro-methyl)-1H-pyrazol-1-yl]benzene sulfonamides 1a-e, which were synthesized by the reaction of alkyl/aryl isothiocyanates with celecoxib. The structures of the isolated products were determined by spectral methods and their anti-inflammatory, analgesic, antioxidant, anticancer and anti-HCV NS5B RNA-dependent RNA polymerase (RdRp) activities evaluated. The compounds were also tested for gastric toxicity and selected compound 1a was screened for its anticancer activity against 60 human tumor cell lines. These investigations revealed that compound 1a exhibited anti-inflammatory and analgesic activities and further did not cause tissue damage in liver, kidney, colon and brain compared to untreated controls or celecoxib. Compounds 1c and 1d displayed modest inhibition of HCV NS5B RdRp activity. In conclusion, N-(ethylcarbamothioyl)-4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide (1a) may have the potential to be developed into a therapeutic agent.

Development, validation and pilot screening of an in vitro multi-cellular three-dimensional cancer spheroid assay for anti-cancer drug testing.

It has been demonstrated that two-dimensional (2D) monolayer cancer cell proliferation assay for anti-cancer drug screening is a very artificial model and cannot represent the characteristics of three-dimensional (3D) solid tumors. The multi-cellular in vitro 3D tumor spheroid model is of intermediate complexity, and can provide a bridge to the gap between the complex in vivo tumors and simple in vitro monolayer cell cultures. In this study, a simple and cost-effective cancer 3D spheroid assay suitable for small molecule anti-cancer compound screening was developed, standardized and validated on H292 non-small lung cancer cell line. A pilot screening with this assay was performed utilizing a compound library consisting of 41 anti-cancer agents. The traditional 2D monolayer cell proliferation assay was also performed with the same cell line and compounds. A correlational study based on the IC(50) values from the 2D and 3D assays was conducted. There is low correlation with the two sets of biological data, suggesting the two screening methods provide different information regarding the potency of the tested drug candidates.