Metabolic Stability Assessed by Liver Microsomes and Hepatocytes

Ackley, David C.; Rockich, Kevin; Baker, Timothy R.

doi:10.1385/1-59259-800-5:151

Cited by 26 publications

(19 citation statements)

References 2 publications

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“…Analysis of metabolic stability of compound 069A, Minaprine (Sigma-Aldrich), and Minozac [ 22 ] was tested in vitro by using commercially available human liver microsomes and an NADPH-regenerating system (BD Biosciences Discovery Labware; Woburn, MA), by the method previously described [ 71 ]. Briefly, triplicate reaction mixtures contained 0.1 M potassium phosphate buffer (pH 7.4) and a final concentration of the following components: 1 – 1.6 mg/ml total microsomal protein, 5 μM test compound, 1.3 mM NADPH, 3.3 mM MgCl 2 , 0.4 U/ml glucose-6-phosphate dehydrogenase, and 3.3 mM glucose-6-phosphate in a total volume of 300 μl.…”

Section: Methodsmentioning

confidence: 99%

A novel p38α MAPK inhibitor suppresses brain proinflammatory cytokine up-regulation and attenuates synaptic dysfunction and behavioral deficits in an Alzheimer's disease mouse model

Munoz

Ranaivo

Roy

et al. 2007

J Neuroinflammation

198

180

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Background: An accumulating body of evidence is consistent with the hypothesis that excessive or prolonged increases in proinflammatory cytokine production by activated glia is a contributor to the progression of pathophysiology that is causally linked to synaptic dysfunction and hippocampal behavior deficits in neurodegenerative diseases such as Alzheimer's disease (AD). This raises the opportunity for the development of new classes of potentially disease-modifying therapeutics. A logical candidate CNS target is p38 MAPK, a well-established drug discovery molecular target for altering proinflammatory cytokine cascades in peripheral tissue disorders. Activated p38 MAPK is seen in human AD brain tissue and in AD-relevant animal models, and cell culture studies strongly implicate p38 MAPK in the increased production of proinflammatory cytokines by glia activated with human amyloid-beta (A ) and other disease-relevant stressors. However, the vast majority of small molecule drugs do not have sufficient penetrance of the bloodbrain barrier to allow their use as in vivo research tools or as therapeutics for neurodegenerative disorders. The goal of this study was to test the hypothesis that brain p38 MAPK is a potential in vivo target for orally bioavailable, small molecules capable of suppressing excessive cytokine production by activated glia back towards homeostasis, allowing an improvement in neurologic outcomes.

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Section: Methodsmentioning

confidence: 99%

A novel p38α MAPK inhibitor suppresses brain proinflammatory cytokine up-regulation and attenuates synaptic dysfunction and behavioral deficits in an Alzheimer's disease mouse model

Munoz

Ranaivo

Roy

et al. 2007

J Neuroinflammation

198

180

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“…The stability of largazole in the presence of mouse microsomes was determined by using an adaptation of a published procedure (Ackley et al, 2004). In brief, microsomes were added to prewarmed phosphate buffer (100 mM, pH 7.4) at 37°C.…”

Section: Stability Studiesmentioning

confidence: 99%

Anticolon Cancer Activity of Largazole, a Marine-Derived Tunable Histone Deacetylase Inhibitor

Liu¹,

Salvador²,

Byeon³

et al. 2010

J Pharmacol Exp Ther

105

141

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Histone deacetylases (HDACs) are validated targets for anticancer therapy as attested by the approval of suberoylanilide hydroxamic acid (SAHA) and romidepsin (FK228) for treating cutaneous T cell lymphoma. We recently described the bioassay-guided isolation, structure determination, synthesis, and target identification of largazole, a marine-derived antiproliferative natural product that is a prodrug that releases a potent HDAC inhibitor, largazole thiol. Here, we characterize the anticancer activity of largazole by using in vitro and in vivo cancer models. Screening against the National Cancer Institute's 60 cell lines revealed that largazole is particularly active against several colon cancer cell types. Consequently, we tested largazole, along with several synthetic analogs, for HDAC inhibition in human HCT116 colon cancer cells. Enzyme inhibition strongly correlated with the growth inhibitory effects, and differential activity of largazole analogs was rationalized by molecular docking to an HDAC1 homology model. Comparative genomewide transcript profiling revealed a close overlap of genes that are regulated by largazole, FK228, and SAHA. Several of these genes can be related to largazole's ability to induce cell cycle arrest and apoptosis. Stability studies suggested reasonable bioavailability of the active species, largazole thiol. We established that largazole inhibits HDACs in tumor tissue in vivo by using a human HCT116 xenograft mouse model. Largazole strongly stimulated histone hyperacetylation in the tumor, showed efficacy in inhibiting tumor growth, and induced apoptosis in the tumor. This effect probably is mediated by the modulation of levels of cell cycle regulators, antagonism of the AKT pathway through insulin receptor substrate 1 down-regulation, and reduction of epidermal growth factor receptor levels.

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“…It is known that hepatic CYP450s play an integral role in phase I metabolism of environmental chemicals and drugs (Ackley et al, 2004; Wu and McKown, 2004; Yan et al, 2002). While it has been shown that cytochrome P450s, CYPs, participate in the detoxification of OPs via the hydrolysis of the OP phospho ester bond to yield DAPs, it has also been demonstrated that CYP-mediated bioactivation of OPs to oxons is a major contributor to overall OP toxicity (Poet et al, 2003; Buratti et al, 2003; Buratti et al, 2005; Busby-Hjerpe et al, 2010; Bharate et al, 2010; Casida and Quistad, 2004).…”

Section: Discussionmentioning

confidence: 99%

Organophosphorus pesticide degradation productin vitrometabolic stability and time-course uptake and elimination in rats following oral and intravenous dosing

Forsberg

Rodriguez-Proteau

et al. 2011

Xenobiotica

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Levels of urinary dialkylphosphates (DAPs) are currently used as a biomarker of human exposure to organophosphorus insecticides (OPs). It is known that OPs degrade on food commodities to DAPs at levels that approach or exceed those of the parent OP. However, little has been reported on the extent of DAP absorption, distribution, metabolism and excretion.The metabolic stability of O,O-dimethylphosphate (DMP) was assessed using pooled human and rat hepatic microsomes. Time-course samples were collected over two hours and analyzed by LC-MS/MS. It was found that DMP was not metabolized by rat or pooled human hepatic microsomes.Male Sprague-Dawley rats were administered DMP at 20 mg kg−1 via oral gavage and I.V. injection. Time-course plasma and urine samples were collected and analyzed by LC-MS/MS. DMP oral bioavailability was found to be 107 ± 39 % and the amount of orally administered dose recovered in the urine was 30 ± 9.9 % by 48 hrs.The in vitro metabolic stability, high bioavailability and extent of DMP urinary excretion following oral exposure in a rat model suggests that measurement of DMP as a biomarker of OP insecticide exposure may lead to overestimation of human exposure.

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Metabolic Stability Assessed by Liver Microsomes and Hepatocytes

Cited by 26 publications

References 2 publications

A novel p38α MAPK inhibitor suppresses brain proinflammatory cytokine up-regulation and attenuates synaptic dysfunction and behavioral deficits in an Alzheimer's disease mouse model

A novel p38α MAPK inhibitor suppresses brain proinflammatory cytokine up-regulation and attenuates synaptic dysfunction and behavioral deficits in an Alzheimer's disease mouse model

Anticolon Cancer Activity of Largazole, a Marine-Derived Tunable Histone Deacetylase Inhibitor

Organophosphorus pesticide degradation productin vitrometabolic stability and time-course uptake and elimination in rats following oral and intravenous dosing

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