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Antioxidant ellagic acid is a herbal polyphenolic compound shown to possess growth-inhibiting and apoptotic activities in cancer. Protein kinase C (PKC) plays an important role in cell proliferation, apoptosis, and differentiation. Apoptosis of tumor cells is induced by inactivation of glycolytic enzyme of anaerobic metabolism, lactate dehydrogenase (LDH)-A, and by activating apoptotic protein caspase-3 via PKCδ. The present study aims to analyze the role of ellagic acid on regulation of novel and atypical isozymes of PKC to modulate apoptosis and anaerobic metabolism to prevent lymphoma growth as its role on classical PKCs is reported earlier. Expression of novel and atypical isozymes of PKC, activity of PKCδ, expression and activity of caspase-3, and LDH-A have been analyzed. Expression is measured by RT-PCR, activities of PKCδ as level of its catalytic fragment, caspase-3 as level of its p17 fragment, and LDH-A by specific staining. Lymphoma bearing mice were treated with 3 different doses of ellagic acid. The treatment enhanced expression of all novel and atypical PKCs, activity and expression of caspase-3, and activity of PKCδ but decreased activity and expression of LDH-A. Our results suggest that ellagic acid induces apoptosis via novel and atypical PKCs in association with caspase-3 and induces cancer cell death by blocking the energy metabolism. [ABSTRACT FROM PUBLISHER]

Zinc deficiency and excess influence cellular homeostasis and are believed to modulate apoptosis. Zinc also regulates cell growth and proliferation. Understanding of the role of zinc in the mechanisms associated with these changes is limited because of its diverse, complex, and cell-specific effects. Therefore, we investigated the oxidative stress responses and the underlying molecular mechanisms associated with the disruption of intracellular zinc homeostasis in H4IIE rat hepatoma cells. We found that zinc excess (100 μM) and DTPA (diethylenetriaminepentaacetic acid; 50–100 μM) induced zinc deficiency both generate reactive oxygen species (ROS) and decrease viability in H4IIE cells. However, cotreatment with the antioxidant, N-acetyl-L-cysteine (NAC) both reduced ROS production and protected cells from death. We additionally observed an increase in Bax mRNA and cytochrome c release from the mitochondria in DTPA-treated cells and an elevated expression of Fas/Fas ligand mRNA with zinc treatment. Both treatments increased p53 and MdM2 protein concentrations along with caspase 3/7 activity. These results suggest that zinc deficiency stimulates mitochondrial-dependent apoptosis whereas zinc activates the extrinsic-apoptotic pathway. Both decreasing and increasing cellular zinc concentrations modulate ROS mediated apoptosis and warrant further research on zinc mediated cancer chemoprevention in this and other cancer cell lines. [ABSTRACT FROM AUTHOR]

Multiple studies have indicated that selective cyclooxygenase-2 (COX-2) inhibitors possess clinically chemopreventive and preclinically anticancer activities. Their long-term use, however, may be limited by the cardiovascular toxicity. This study tried to investigate whether an apple oligogalactan (AOG) could enhance the growth inhibitory effect of celecoxib on colorectal cancer. Caco-2 and HT-29 cell lines were exposed to different concentrations of AOG (0–1 g/L), celecoxib (0–25 μmol/L), and their combination. COX-2 levels were assessed by reverse transcription PCR and Western blot. COX-2 activity was evaluated by measuring prostaglandin E2 concentration. A colitis-associated colorectal cancer (CACC) mouse model was used to determine the effect of the combination in vivo. AOG (0.1–0.5 g/L) could potentiate the inhibitory effect of physiologic doses of celecoxib (5 μmol/L) on cell growth and decrease COX-2 expressions both at RNA and protein levels. In vivo, the combination (2.5% AOG plus 0.04% celecoxib, w/w) prevented against CACC in mice effectively. Our data indicate that AOG could potentiate the growth inhibitory effect of celecoxib on colorectal cancer both in vitro and in vivo through influencing the expression and function of COX-2 and phosphorylation of MAPKs, which suggests a new possible combinatorial strategy in colorectal cancer therapy. [ABSTRACT FROM AUTHOR]

Conclusion. Since aquaporin-6 (Aqp6) protein was located in the membrane of intracellular vesicles of the stria vascularis, endolymphatic sac, and vestibule, Aqp6 might be involved in some distinct physiological function of acid-base metabolism and water balance in endolymphatic fluid homeostasis. However, its lack of expression on the plasma membrane indicates that Aqp6 does not have a direct role in water flux via the plasma membrane. Objective. To evaluate the expression and immunolocalization of Aqp6 in the rat inner ear. Materials and methods. Wistar rats were used. Aqp6 mRNA expression in the rat inner ear was investigated in the vestibulum as well as in the cochlea and endolymphatic sac using the reverse transcription-polymerase chain reaction (RT-PCR) method, and detailed immunolocalization of Aqp6 in the rat inner ear was investigated using immunohistochemical methods including immunofluorescence microscopy and immunoelectron microscopy. Results. We obtained novel data showing that not just Aqp6 mRNA but also Aqp6 protein is expressed in the cochlea, endolymphatic sac, and vestibule. Immunoelectron microscopic studies revealed that the immunolabelled gold was diffusely seen in the intracellular area of the stria vascularis, endolymphatic sac, and vestibule, but never in the plasma membranes. [ABSTRACT FROM AUTHOR]

The disposition of compound A, a potent inhibitor of the hepatitis C virus (HCV) NS5B polymerase, was characterized in animals in support of its selection for further development. Compound A exhibited marked species differences in pharmacokinetics. Plasma clearance was 44  ml  min -1   kg -1 in rats, 9  ml  min -1   kg -1 in dogs and 16  ml  min -1   kg -1 in rhesus monkeys. Oral bioavailability was low in rats (10%) but significantly higher in dogs (52%) and monkeys (26%). Compound A was eliminated primarily by metabolism in rats, with biliary excretion accounting for 30% of its clearance. Metabolism was mainly mediated by cyclohexyl hydroxylation, with N-deethylation and acyl glucuronide formation constituting minor metabolic pathways. Qualitatively, the same metabolites were identified using in vitro systems from all species studied, including humans. The low oral bioavailability of compound A in rats was mostly due to poor intestinal absorption. This conclusion was borne out by the findings that hepatic extraction in the rat was only 30%, intraperitoneal bioavailability was good, and compound A was poorly absorbed from the rat isolated intestinal loop, with no detectable intestinal metabolism. Compound A was not an inhibitor of major human cytochrome P450 enzymes, indicating minimal potential for clinical drug–drug interactions. The metabolic clearance of compound A in rat, dog and monkey hepatocytes correlated with the systemic clearance observed in these species. Since compound A was very stable in human hepatocytes, the results suggest that it will be a low clearance drug in humans. [ABSTRACT FROM AUTHOR]

Objective: In the development of autoimmune diseases, dendritic cells (DC) play critical roles. Here, we examined the effect of aspirin on lipopolysaccharide (LPS)-induced DC activation.Methods: The monocyte-derived DC were established. The cytokine production was measured by ELISA, reverse transcriptase/polymerase chain reaction, or intracellular staining analyzed by flow cytometry. The expression of cell surface molecules was determined by flow cytometry.Results: Aspirin inhibited LPS-induced DC maturation and costimulatory molecules expression. Aspirin, at therapeutic concentrations, also decreased LPS-induced IL-12 and IL-10 production. In contrast, the LPS-induced TNF-alpha production was enhanced by aspirin. The differential effects of aspirin on IL-12 and TNF-alpha production may not be due to down-regulation of cyclooxygenase activities.Conclusion: The various effects of aspirin on LPS-stimulated DC may influence the understanding of the diverse immunomodulatory mechanisms of this anti-inflammatory drug. [ABSTRACT FROM AUTHOR]