RETRACTED: Resveratrol induces apoptosis involving mitochondrial pathways in mouse skin tumorigenesis

Resveratrol induces apoptosis via a Bak-mediated intrinsic pathway in human lung adenocarcinoma cells

Our recent study have shown that resveratrol (RV), a natural plant polyphenol found in red grape skins as well as other food product, induced apoptosis via the downstream factors, caspase-independent AIF and to lesser extent caspase-9, of intrinsic apoptosis pathway in human lung adenocarcinoma (ASTC-a-1) cells. This report is designed to explore the roles of the upstream mediators of the intrinsic pathway, such as Bak/Bax, Bim, Puma and Noxa, during RV-induced apoptosis in human lung adenocarcinoma (ASTC-a-1 and A549) cell lines. RV treatment remarkably induced the activation of Bak but not Bax, and silencing Bak but not Bax by shRNA almost completely prevented RV-induced cell death, mitochondrial dysfunction and also largely prevented RV-induced AIF release, demonstrating the preferential engagement of Bak but not Bax during RV-induced apoptosis. In addition, although RV treatment induced a significant degradation of Mcl-1, knockdown of Mcl-1 by shRNA only modestly increased RV-induced Bak activation. Interestingly, silencing Bim but not Puma and Noxa remarkably attenuated RV-induced cell death, loss of mitochondrial membrane potential, and Bak activation, suggesting the important roles of Bim. Collectively, our findings for the first time demonstrate that RV induces apoptosis dominantly via a Bak- but not Bax-mediated AIF-dependent mitochondrial apoptotic signaling pathway in which Bim but not Puma and Noxa may supply the force to trigger Bak activation and subsequent apoptosis in both ASTC-a-1 and A549 cell lines.

Resveratrol and black tea polyphenol combination synergistically suppress mouse skin tumors growth by inhibition of activated MAPKs and p53

Cancer chemoprevention by natural dietary agents has received considerable importance because of their cost-effectiveness and wide safety margin. However, single agent intervention has failed to bring the expected outcome in clinical trials; therefore, combinations of chemopreventive agents are gaining increasing popularity. The present study aims to evaluate the combinatorial chemopreventive effects of resveratrol and black tea polyphenol (BTP) in suppressing two-stage mouse skin carcinogenesis induced by DMBA and TPA. Resveratrol/BTP alone treatment decreased tumor incidence by ∼67% and ∼75%, while combination of both at low doses synergistically decreased tumor incidence even more significantly by ∼89% (p<0.01). This combination also significantly regressed tumor volume and number (p<0.01). Mechanistic studies revealed that this combinatorial inhibition was associated with decreased expression of phosphorylated mitogen-activated protein kinase family proteins: extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase 1/2, p38 and increased in total p53 and phospho p53 (Ser 15) in skin tissue/tumor. Treatment with combinations of resveratrol and BTP also decreased expression of proliferating cell nuclear antigen in mouse skin tissues/tumors than their solitary treatments as determined by immunohistochemistry. In addition, histological and cell death analysis also confirmed that resveratrol and BTP treatment together inhibits cellular proliferation and markedly induces apoptosis. Taken together, our results for the first time lucidly illustrate that resveratrol and BTP in combination impart better suppressive activity than either of these agents alone and accentuate that development of novel combination therapies/chemoprevention using dietary agents will be more beneficial against cancer. This promising combination should be examined in therapeutic trials of skin and possibly other cancers.

Nomilin Inhibits Metastasis via Induction of Apoptosis and Regulates the Activation of Transcription Factors and the Cytokine Profile in B16F-10 Cells

Nomilin is a triterpenoid present in common edible citrus fruits with putative anticancer properties. In this study, the authors investigated the antimetastatic potential of nomilin and its possible mechanism of action. Metastasis was induced in C57BL/6 mice through the lateral tail vein using highly metastatic B16F-10 melanoma cells. Administration of nomilin inhibited tumor nodule formation in the lungs (68%) and markedly increased the survival rate of the metastatic tumor–bearing animals. These results correlated with the biochemical parameters and histopathological analysis. Nomilin showed an inhibition of tumor cell invasion and activation of matrix metalloproteinases. Treatment with nomilin induced apoptotic response, characterized by an increase in the sub-G1 fraction of cells with chromatin condensation and membrane blebbing, a typical ladder of DNA fragmentation, and detection of apoptotic cells by TUNEL assay. Nomilin treatment also exhibited a downregulated Bcl-2 and cyclin-D1 expression and upregulated p53, Bax, caspase-9, caspase-3, p21, and p27 gene expression in B16F-10 cells. Proinflammatory cytokine production and gene expression were found to be downregulated in nomilin-treated cells. The study also reveals that nomilin could inhibit the activation and nuclear translocation of antiapoptotic transcription factors such as nuclear factor (NF)-κB, CREB, and ATF-2 in B16F-10 cells.

A single-dose resveratrol treatment in a mouse model of amyotrophic lateral sclerosis

The underlying causes of denervation of the neuromuscular junction and eventual motor neuron death in amyotrophic lateral sclerosis (ALS) have not been resolved. The superoxide dismutase 1 (SOD1)(G93A) mutant mouse is a frequently used animal model of ALS. We hypothesized that resveratrol (RSV), a polyphenolic molecule that enhances mammalian NAD(+)-dependent SIRT1 deacetylases and may increase life span, would improve motor function and survival in the SOD1 mouse model via modulation of p53 acetylation. Data were collected for mean survival times, neuromuscular performance on the ROTOR-ROD™ (San Diego Instruments, San Diego, CA, USA), body weight, and p53 acetylation. Mean survival times were not statistically different (P=.23) between control and experimental (RSV-fed) groups (mean +/- SD, control [n=11] 138 +/- 6 days vs. experimental [n=10] 135 +/- 8 days). Performance was not significantly different between groups at time points corresponding to 50%, 80%, and 90% mean life span (P=.46), nor did RSV treatment attenuate body weight loss. Thus although manipulation of SIRT1 deacetylase activity has effects at the protein level in healthy aging organisms, we conclude that RSV treatment does not lead to functional improvement or increased longevity in a mouse model of ALS. We speculate that RSV-mediated modulation of p53 acetylation is either incapable of increasing or insufficient to increase motor performance and longevity in this model of ALS.

The grape antioxidant resveratrol for skin disorders: promise, prospects, and challenges

Resveratrol, a phytoalexin antioxidant found in red grapes, has been shown to have both chemopreventive and therapeutic effects against many diseases and disorders, including those of the skin. Studies have shown protective effects of resveratrol against ultraviolet radiation-mediated oxidative stress and cutaneous damages including skin cancer. Because many of the skin conditions stem from ultraviolet radiation and oxidative stress, this antioxidant appears to have promise and prospects against a wide range of cutaneous disorders including skin aging and skin cancers. However, there are a few roadblocks in the way of this promising agent regarding its translation from the bench to the bedside. This review discusses the promise and prospects of resveratrol in the management of skin disorders and the associated challenges.

Treatment of ovarian cancer cells with nutlin-3 and resveratrol combination leads to apoptosis via caspase activation

The current study was focused on the induction of apoptotic effects of resveratrol along with the combination treatments of nutlin-3 and transforming growth factor-β (TGF-β) against the human ovarian cancer cell line A2780/CP70. To determine the extent of apoptosis following the above-mentioned treatments, we assessed the execution of apoptotic events that proceed via caspase activation and cytochrome c release. We estimated the caspase-3 and -9 activities using a direct enzymatic assay that measures the cleavage of synthetic peptide substrate (N-acetyl-Asp-Glu-Val-Asp-p-nitroanilide). Our experiments showed an increase in caspase-3 and -9 activities in the cells that were treated with the combination of resveratrol (5 μM) with nutlin-3 (5 μM) or TGF-β (1 μg/mL). Since activation of procaspase-3 by caspase-9 requires the release of cytochrome c into the cytoplasm, we measured the levels of cytochrome c in the cytoplasm by western blot experiments. The data indicated a considerable increase in caspase-3 and cytochrome c levels when cells were treated with drugs for 24 hours. Experiments with 4,6'-diamino-2-phenylindole dihydrochloride (DAPI) staining also confirmed the induction of apoptosis in all the above-mentioned treatments done at 24 and 48 hours. These results support our hypothesis that resveratrol combination can induce programmed cell death at doses that are less than half of what is typically needed for nutlin-3 and TGF-β to induce apoptosis.

Resveratrol, a red wine polyphenol, suppresses pancreatic cancer by inhibiting leukotriene A₄hydrolase

The anticancer effects of red wine have attracted considerable attention. Resveratrol (3,5,4'-trihydroxy-trans -stilbene) is a well-known polyphenolic compound of red wine with cancer chemopreventive activity. However, the basis for this activity is unclear. We studied leukotriene A(4) hydrolase (LTA(4)H) as a relevant target in pancreatic cancer. LTA(4)H knockdown limited the formation of leukotriene B(4) (LTB(4)), the enzymatic product of LTA(4)H, and suppressed anchorage-independent growth of pancreatic cancer cells. An in silico shape similarity algorithm predicted that LTA(4)H might be a potential target of resveratrol. In support of this idea, we found that resveratrol directly bound to LTA(4)H in vitro and in cells and suppressed proliferation and anchorage-independent growth of pancreatic cancer by inhibiting LTB(4) production and expression of the LTB(4) receptor 1 (BLT(1)). Notably, resveratrol exerted relatively stronger inhibitory effects than bestatin, an established inhibitor of LTA(4)H activity, and the inhibitory effects of resveratrol were reduced in cells where LTA(4)H was suppressed by shRNA-mediated knockdown. Importantly, resveratrol inhibited tumor formation in a xenograft mouse model of human pancreatic cancer by inhibiting LTA(4)H activity. Our findings identify LTA(4)H as a functionally important target for mediating the anticancer properties of resveratrol.

Topical application of valrubicin has a beneficial effect on developing skin tumors

Valrubicin is a second generation anthracycline characterized by an excellent safety profile presenting no skin toxicity or necrosis upon contact. In its current liquid formulation (Valstar; Indevus Pharmaceuticals, Lexington, MA), it is approved solely for the treatment of bladder cancer. Recently, valrubicin was incorporated in a cream formulation rendering this drug available for topical application. The cytostatic property of valrubicin can, thus, be employed for treating hyperproliferative skin diseases as was recently described for psoriasis. In the present study, the effect of topical application of valrubicin was investigated in skin tumor development; we hypothesized that valrubicin may be employed in treating actinic keratosis, a hyperproliferative skin condition that may transform into malignancy. A two-stage chemical mouse skin carcinogenesis model that represents the multistage etiology of human skin cancer-from developing papillomas to squamous cell carcinoma (SCC) was used. Moreover, two human skin SCC cell lines: DJM-1 and HSC-1 were cultured, to further investigate the effect of valrubicin in vitro. Cell viability was assessed by adenosine triphosphate presence, proliferation as proliferative cell nuclear antigen expression and apoptosis as cytokeratin 18 cleavage, caspase activation, poly-adenosine diphosphate-ribose-polymerase cleavage and bax and bcl-2 regulation. Valrubicin significantly inhibited tumor formation in the mouse skin carcinogenesis model and significantly decreased cell viability of the cultured human skin SCC cells. In both mouse skin and SCC cells, proliferation was significantly decreased. Apoptosis was significantly increased in SCC cells but unchanged in the treated mouse skin at study completion. This study demonstrated that topical application of valrubicin has a beneficial effect in treating developing skin tumors.

Nutritional approach to sun protection: a suggested complement to external strategies

The increasing incidence of skin cancer despite the use of externally applied sun protection strategies, alongside research showing that nutrients reduce photo-oxidative damage, suggest nutritional approaches could play a beneficial role in skin cancer prevention. Penetrating photo-oxidative ultraviolet A radiation reduces skin and blood antioxidants and damages cell components, including DNA. Dietary antioxidant vitamins, minerals, and phytochemicals in addition to n-3 polyunsaturated fatty acids, n-9 monounsaturated fatty acids, and low pro-inflammatory n-6 polyunsaturated fatty acids, have demonstrated protective properties. The presence of these elements in the traditional Greek-style Mediterranean diet may have contributed to the low rates of melanoma in the Mediterranean region despite high levels of solar radiation. This suggests a potentially relevant model for studying dietary/nutritional supplementation for lifelong internal support of sun-protection mechanisms, which could complement external strategies.

Mechanisms of apoptotic effects induced by resveratrol, dibenzoylmethane, and their analogues on human lung carcinoma cells

While lung cancer accounts for approximately 20% of cancer diagnoses, it is the leading cause of tumor-related deaths. The apoptotic effects of 3,5,4'-trihydroxystilbene (resveratrol), dibenzoylmethane (DBM), and their analogues on human lung cancer cells are generally unclear. The aims of this study were to evaluate the apoptotic effects and molecular mechanisms of resveratrol, DBM, and their analogues on human lung cancer cells. The results of the MTT and lactate dehydrogenase (LDH) leakage assays indicated that resveratrol, 3,5,4'-trimethoxy-trans-stilbene (MR-3), and 1-(2-hydroxy-5-methylphenyl)-3-phenyl-1,3-propanedione (HMDB) could inhibit cell population growth and induce cell injury in A549 and CH27 cell lines. Resveratrol and HMDB could induce apoptotic cell death in the A549 and CH27 cell lines. Moreover, cellular growth of the A549 and CH27 cell lines might be inhibited by MR-3 through induction of apoptosis and regulation of the cell cycle. The A549 and CH27 cell lines treated with resveratrol, MR-3, and HMDB showed a time-dependent reduction of mitochondrial membrane potential, and the Bax/Bcl-2 ratio increased gradually with a higher concentration of polyphenols. The resveratrol-, MR-3-, and HMDB-induced apoptosis in the A549 and CH27 cell lines were controlled through activation of caspase-9 and caspase-3 and subsequent cleavage of PARP. In conclusion, we have demonstrated that resveratrol, DBM, and their analogues could be effective candidates for chemoprevention of lung cancer and HMDB might have the strongest ability for inducing apoptosis.

Inhibition of suicidal erythrocyte death by resveratrol

AIMS

Pleiotropic effects of resveratrol include antioxidant activity and inhibition of cyclooxygenase with decrease of PGE(2) formation. In erythrocytes oxidation and PGE(2) activate Ca(2+)-permeable cation channels. The Ca(2+)-entry leads to activation of Ca(2+)-sensitive K(+) channels with subsequent cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the erythrocyte surface. Cell shrinkage and phosphatidylserine exposure are hallmarks of suicidal erythrocyte death or eryptosis. Eryptotic cells adhere to the vascular wall thus compromising microcirculation and are cleared from circulating blood thus leading to anemia. The present experiments explored whether resveratrol influences eryptosis.

MAIN METHODS

Erythrocyte phosphatidylserine exposure was identified by annexin V-binding, cell volume estimated from forward scatter and cytosolic Ca(2+) activity determined utilizing Fluo3 fluorescence in FACS analysis.

KEY FINDINGS

Energy depletion (48 h glucose removal) significantly increased Fluo3 fluorescence and annexin V-binding and decreased forward scatter, effects significantly blunted by resveratrol (>/=5 microM). Moreover, oxidative stress (30 min 0.3 mM tert-butylhydroperoxide) and isoosmotic cell shrinkage (48 h replacement of extracellular chloride by gluconate) similarly triggered eryptosis, effects again significantly blunted in the presence of resveratrol.

SIGNIFICANCE

Resveratrol is a potent inhibitor of suicidal erythrocyte death during energy depletion, oxidative stress and isoosmotic cell shrinkage. The nutrient could thus counteract anemia and impairment of microcirculation under conditions with excessive eryptosis.

Cancer prevention and treatment with resveratrol: from rodent studies to clinical trials

Resveratrol (3,4',5-trihydroxy-trans-stilbene) is a dietary polyphenol derived from grapes, berries, peanuts, and other plant sources. During the last decade, resveratrol has been shown to possess a fascinating spectrum of pharmacologic properties. Multiple biochemical and molecular actions seem to contribute to resveratrol effects against precancerous or cancer cells. Resveratrol affects all three discrete stages of carcinogenesis (initiation, promotion, and progression) by modulating signal transduction pathways that control cell division and growth, apoptosis, inflammation, angiogenesis, and metastasis. The anticancer property of resveratrol has been supported by its ability to inhibit proliferation of a wide variety of human tumor cells in vitro. These in vitro data have led to numerous preclinical animal studies to evaluate the potential of this drug for cancer chemoprevention and chemotherapy. This review provides concise, comprehensive data from preclinical in vivo studies in various rodent models of human cancers, highlighting the related mechanisms of action. Bioavailability, pharmacokinetic, and potential toxicity studies of resveratrol in humans and ongoing interventional clinical trials are also presented. The conclusion describes directions for future resveratrol research to establish its activity and utility as a human cancer preventive and therapeutic drug.

Resveratrol prevents the expression of glaucoma markers induced by chronic oxidative stress in trabecular meshwork cells

Elevated intraocular pressure (IOP) constitutes the best characterized risk for primary open-angle glaucoma (POAG). Elevated IOP is believed to result from an increase in aqueous humor outflow resistance at the level of the trabecular meshwork (TM)/Schlemm's canal. Malfunction of the TM in POAG is associated with the expression of markers for inflammation, cellular senescence, oxidative damage, and decreased cellularity. Current POAG treatments rely on lowering IOP, but there is no therapeutic approach available to delay the loss of function of the TM in POAG patients. We evaluated the effects of chronic administration of the dietary supplement resveratrol on the expression of markers for inflammation, oxidative damage, and cellular senescence in primary TM cells subjected to chronic oxidative stress (40% O2). Resveratrol treatment effectively prevented increased production of intracellular reactive oxygen species (iROS) and inflammatory markers (IL1alpha, IL6, IL8, and ELAM-1), and reduced expression of the senescence markers sa-beta-gal, lipofuscin, and accumulation of carbonylated proteins. Furthermore, resveratrol exerted antiapoptotic effects that were not associated with a decrease in cell proliferation. These results suggest that resveratrol could potentially have a role in preventing the TM tissue abnormalities observed in POAG.

Apoptosis by dietary agents for prevention and treatment of cancer

The role of apoptosis or programmed cell death in the regulation of development and maintenance of homeostasis in multicellular organisms is well established. During the last decade, naturally occurring dietary agents known to produce chemopreventive effects in experimental models have been shown to target signaling intermediates in apoptosis-inducing pathways. Apoptosis is triggered by two different signals, one extrinsic, which responds mainly to extracellular stimuli, and the other intrinsic, activated by modulators within the cell itself. Proapoptotic compounds could protect against cancer by enhancing elimination of initiated, precancerous cells, and antiapoptotic compounds could promote tumor formation by inhibiting apoptosis in genetically damaged cells. In this brief review, we explore the potential mechanistic interactions of various dietary cancer chemopreventive components within the context of apoptosis.

Cancer chemopreventive and therapeutic potential of resveratrol: mechanistic perspectives

A plant kingdom is considered as a gold mine for the discovery of many biologically active substances with therapeutic values. Resveratrol (3,5,4'-trihydroxystilbene), a naturally occurring polyphenol, exhibits pleiotropic health beneficial effects including anti-oxidant, anti-inflammatory, cardioprotective and anti-tumor activities. Currently, numerous preclinical findings suggest resveratrol as a promising nature's arsenal for cancer prevention and treatment. A remarkable progress in dissecting the molecular mechanisms underlying anti-cancer properties of resveratrol has been achieved in the past decade. As a potential anti-cancer agent, resveratrol has been shown to inhibit or retard the growth of various cancer cells in culture and implanted tumors in vivo. The compound significantly inhibits experimental tumorigenesis in a wide range of animal models. Resveratrol targets many components of intracellular signaling pathways including pro-inflammatory mediators, regulators of cell survival and apoptosis, and tumor angiogenic and metastatic switches by modulating a distinct set of upstream kinases, transcription factors and their regulators. This review summarizes the diverse molecular targets of resveratrol with a special focus on those involved in fine-tuning of orchestrated intracellular signal transduction.