Resveratrol induces gastric cancer cell apoptosis via reactive oxygen species, but independent of sirtuin1

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Resveratrol-induced inactivation of human gastric adenocarcinoma cells through a protein kinase C-mediated mechanism.

Resveratrol, a polyphenolic phytochemical present in berries, grapes, and wine, has emerged as a promising chemopreventive candidate. Because there is scant information regarding natural agents that prevent, suppress, or reverse gastric carcinogenesis, the aim of the present study was to determine the chemopreventive potential of resveratrol against gastric cancer by investigating cellular and molecular events associated with resveratrol treatment of human gastric adenocarcinoma cells. We determined the action of resveratrol on cellular function and cellular integrity by measuring DNA synthesis, cellular proliferation, cell cycle distribution, cytolysis, apoptosis, and phosphotransferase activities of two key signaling enzymes, protein kinase C (PKC) and mitogen-activated protein kinases (ERK1/ERK2), in human gastric adenocarcinoma KATO-III and RF-1 cells. Resveratrol inhibited [3H]thymidine incorporation into cellular DNA of normally proliferating KATO-III cells and of RF-1 cells whose proliferation was stimulated with carcinogenic nitrosamines. Treatment with resveratrol arrested KATO-III cells in the G(0)/G(1) phase of the cell cycle and eventually induced apoptotic cell death, but had a minimal effect on cell lysis. Resveratrol treatment had no effect on ERK1/ERK2 activity but significantly inhibited PKC activity of KATO-III cells and of human recombinant PKCalpha. Results indicate that resveratrol has potential as a chemopreventive agent against gastric cancer because it exerts an overall deactivating effect on human gastric adenocarcinoma cells. Resveratrol-induced inhibition of PKC activity and of PKCalpha, without any change in ERK1/ERK2 activity, suggests that resveratrol utilizes a PKC-mediated mechanism to deactivate gastric adenocarcinoma cells.     

Repeated resveratrol administration confers lasting protection against neuronal damage but induces dose-related alterations of behavioral impairments after global ischemia

Resveratrol, a naturally occurring polyphenol, has been shown to protect the heart and brain against ischemic injury. The current study investigated the effects of administration with either a 1 or 10-mg/kg dose of resveratrol on CA1 neuronal injury and behavioral/cognitive impairments after 10-min global ischemia in rats. The open-field, eight-arm radial maze and object recognition tests served to evaluate effects of resveratrol treatment on ischemia-induced locomotor activity, and spatial and recognition memory impairments, respectively. CA1 and CA3 neuronal injury was assessed upon completion of behavioral testing, 85 days postischemia. A separate series of groups served to assess neuronal injury at 7 days postischemia. Global ischemia (10 min) led to approximately 50% CA1 cell injury, which was prevented at both short (7 days) and long (85 days) postischemic intervals by resveratrol treatment. Importantly, despite comparable neuronal protection, the two resveratrol doses showed distinct behavioral effects. Thus, the 10-mg/kg resveratrol dose led to an enhanced locomotor activity in the open-field 4-days postischemia and an impaired spatial memory in the delayed nonmatching to sample and delayed matching to sample radial-maze tasks initiated on day 13 postischemia. These findings suggest independent actions of resveratrol on distinct physiological systems mediating cellular survival and functional recovery and dose-related actions of the polyphenol on behavioral and memory processes.     

Neuroprotective effect of resveratrol against methamphetamine-induced dopaminergic apoptotic cell death in a cell culture model of neurotoxicity

A growing body of evidence suggests that oxidative stress-mediated cell death signaling mechanisms may exert neurotoxic effects of methamphetamine (MA)-induced dopaminergic neuronal loss. However, the means by which oxidative stress induced by MA causes neurodegeneration remains unclear. In recent years, resveratrol has garnered considerable attention owing to its antioxidant, anti-inflammatory, anti-aging, and neuroprotective properties. In the present study, we sought to investigate the neuroprotective effects of resveratrol against apoptotic cell death in a mesencephalic dopaminergic neuronal cell culture model of MA neurotoxicity. MA treatment in the N27 dopaminergic neuronal cell model produced a time-dependent activation of the apoptotic cascade involving caspase-3 and DNA fragmentation. We found that the caspase-3 activation preceded DNA fragmentation. Notably, treatment with resveratrol almost completely attenuated MA-induced caspase-3 activity, but only partially reduced apoptotic cell death. We conclude that the neuroprotective effect of resveratrol is at least in part mediated by suppression of caspase-3 dependent cell death pathways. Collectively, our results demonstrate that resveratrol can attenuate MA-induced apoptotic cell death and suggest that resveratrol or its analogs may have therapeutic benefits in mitigating MA-induced dopaminergic neurodegeneration.     

Role of KATP channels and TRPV1 receptors in hydrogen sulfide-enhanced gastric emptying of liquid in awake mice

In the treatment of Parkinson's disease, potent disease-modifying drugs are still needed to halt progressive dopaminergic neurodegeneration. We have previously shown that meloxicam, an oxicam non-steroidal anti-inflammatory drug (NSAID), elicits a potent neuroprotective effect against 1-methyl-4-phenyl pyridinium (MPP(+))-induced toxicity in human dopaminergic SH-SY5Y neuroblastoma cells. This cyclooxygenase-independent neuroprotection of meloxicam is mediated via the phosphatidylinositol 3-kinase (PI3K)/Akt pathway; however, the specific chemical structure involved in inducing neuroprotection remains unresolved. In this study, we therefore investigated the structure-specific for eliciting the neuroprotective effect by examining a series of NSAIDs against MPP(+) toxicity in SH-SY5Y cells. Three oxicam-bearing NSAIDs showed potent neuroprotective effects, although none of the other 10 oxicam-nonbearing NSAIDs (3 salicylates, 6 coxibs and 1 polyphenol) or 3 piroxicam analogs (including ampiroxicam, a precursor of piroxicam) exerted any neuroprotection. Tenoxicam and piroxicam prevented MPP(+)-induced reduction of phosphorylated Akt levels in cells: a protective mechanism similar to that of meloxicam. Therefore, the oxicam structure was likely to be responsible for exhibiting the neuroprotection by sustaining survival-signaling in dopaminergic cells. The present results raise the possibility that the oxicam-bearing NSAIDs may serve as potential therapeutic drugs to retard or terminate progression of Parkinson's disease via a novel mechanism.     

Effects of Resveratrol and trans-3,5,4’-Trimethoxystilbene on Glutamate-Induced Cytotoxicity,Heme Oxygenase-1, and Sirtuin 1 in HT22 Neuronal Cells

Resveratrol (trans-3,5,4’-trihydroxystilbene) has received considerable attention recently for the potential neuroprotective effects in neurodegenerative disorders where heme oxygenase-1 (HO-1) and sirtuin 1 (SIRT1) represent promising therapeutic targets. Resveratrol has been known to increase HO-1 expression and SIRT1 activity. In this study, the effects of resveratrol and trans-3,5,4’-trimethoxystilbene (TMS), a resveratrol derivative, on cytotoxicity caused by glutamate-induced oxidative stress, HO-1 expression, and SIRT1 activation have been investigated by using murine hippocampal HT22 cells, which have been widely used as an in vitro model for investigating glutamate-induced neurotoxicity. Resveratrol protected HT22 neuronal cells from glutamateinduced cytotoxicity and increased HO-1 expression as well as SIRT1 activity in a concentration-dependent manner. Cytoprotec-tion afforded by resveratrol was partially reversed by the specific inhibition of HO-1 expression by HO-1 small interfering RNA and the nonspecific blockage of HO-1 activity by tin protoporphyrin IX, but not by SIRT1 inhibitors. Surprisingly, TMS, a resveratrol derivative with methoxyl groups in lieu of the hydroxyl groups, and trans-stilbene, a non-hydroxylated analog, failed to protect HT22 cells from glutamate-induced cytotoxicity and to increase HO-1 expression and SIRT1 activity. Taken together, our findings suggest that the cytoprotective effect of resveratrol was at least in part associated with HO-1 expression but not with SIRT1 activation and, importantly, that the presence of hydroxyl groups on the benzene rings of resveratrol appears to be necessary for cytoprotection against glutamate-induced oxidative stress, HO-1 expression, and SIRT1 activation in HT22 neuronal cells.     

Resveratrol prevents bradykinin-induced contraction of rat urinary bladders by decreasing prostaglandin production and calcium influx

Resveratrol, a polyphenol found in grapes and peanuts, exerts beneficial effects on a number of diseases of cardiovascular and central nervous system. However, effects of resveratrol on the urinary system have not been fully investigated. In the present study, we examined effects of resveratrol on bradykinin-induced contraction and release of prostaglandin E2 in isolated rat urinary bladders. The effects of resveratrol on contractions induced by several agonists (prostaglandin E2, prostaglandin F2α and carbachol) and high K+ were also examined. We found that resveratrol concentration-dependently reduced the bradykinin-induced contraction in the rat urinary bladder preparations. The higher concentration of resveratrol (100 μM) abolished the bradykinin-induced prostaglandin E2 release. Similar results were obtained when the cyclooxygenase inhibitor indomethacin (10 μM) was used instead of resveratrol. Resveratrol also attenuated the prostaglandin E2-, prostaglandin F2α-, and to a lesser extent carbachol-induced contractions. Contractile responses to bradykinin, prostaglandin E2 and carbachol were largely prevented by blockade of Ca2+ channels with diltiazem. Both resveratrol and diltiazem prevented contractions induced by an addition of Ca2+ (2.5- 10 mM) into Ca2+-free/50 mMK+ solution or by 50 mMK+ solution containing normal Ca2+ (2.5 mM). These results suggest that resveratrol prevents bradykinin-induced contractions by attenuating not only the production of prostaglandins but also actions of them. The effect of resveratrol on contractile actions seems to be in part due to inhibition of Ca2+ influx. Because bradykinin plays an important role in pathological conditions of urinary bladder function, resveratrol may exert beneficial effects on the urinary bladder diseases.     

Resveratrol reduces vacuous chewing movements induced by acute treatment with fluphenazine

Treatment with classical neuroleptics in humans can produce a serious side effect, known as tardive dyskinesia (TD). Here, we examined the possible neuroprotective effects of resveratrol, a polyphenol compound contained in red grapes and red wine, in an animal model of orofacial dyskinesia (OD) induced by acute treatment with fluphenazine. Adult male rats were treated during 3 weeks with fluphenazine enantate (25 mg/kg, i.m., single administration) and/or resveratrol (1 mg/kg, s.c., 3 times a week). Vacuous chewing movements (VCMs), locomotor and exploratory performance were evaluated. Fluphenazine treatment produced VCM in 70% of rats and the concomitant treatment with resveratrol decreased the prevalence to 30%, but did not modify the intensity of VCMs. Furthermore, the fluphenazine administration reduced the locomotor and exploratory activity of animals in the open field test. Resveratrol co-treatment was able to protect the reduction of both parameters. Taken together, our data suggest that resveratrol could be considered a potential neuroprotective agent by reducing motor disorders induced by fluphenazine treatment.     

Neuroprotective effect of resveratrol on 6-OHDA-induced Parkinson's disease in rats

The present study was undertaken to investigate the neuroprotective effects of resveratrol on 6-hydroxydopamine (6-OHDA)-induced Parkinson's disease in rats. 6-OHDA-induced Parkinson's disease rat model involves chronic inflammation, mitochondrial dysfunction, and oxidative stress, and the loss of the dopaminergic neurons in the substantia nigra is the predominant lesion. Resveratrol has been shown to have anti-inflammatory actions, and thus was tested for its beneficial effects using 6-OHDA-induced Parkinson's disease rat model. Adult Sprague–Dawley (SD) rats were unilaterally injected with 6-OHDA (5 µg/2 µl) into the right striatum, and the striatum damage was assessed by rotational test, ultrahistopathology, and molecular alterations. Resveratrol (10, 20 and 40 mg/kg) was then given orally to Parkinson's disease rats, daily for 10 weeks to examine the protective effects. Rotational test (turns of rats) showed that resveratrol significantly attenuated apomorphine-induced turns of rats in 6-OHDA-injuried Parkinson's disease rat model as early as two weeks of administration. Ultrastructural analysis showed that resveratrol alleviated 6-OHDA-induced chromatin condensation, mitochondrial tumefaction and vacuolization of dopaminergic neurons in rat substantia nigra. Furthermore, resveratrol treatment also significantly decreased the levels of COX-2 and TNF-α mRNA in the substantia nigra as detected by real-time RT-PCR. COX-2 protein expression in the substantia nigra was also decreased as evidenced by Western blotting. These results demonstrate that resveratrol exerts a neuroprotective effect on 6-OHDA-induced Parkinson's disease rat model, and this protection is related to the reduced inflammatory reaction.