Resveratrol inhibits rhabdomyosarcoma cell proliferation

Alternations of NF-κB Signaling by Natural Compounds in Muscle-Derived Cancers

The NF-κB-signaling pathway plays a crucial role in cancer progression, including muscle-derived cancers such as rhabdomyosarcoma or sarcoma. Several natural compounds have been studied for their ability to alter NF-κB signaling in these types of cancers. This review paper summarizes the current knowledge on the effects of natural compounds, including curcumin, resveratrol, quercetin, epigallocatechin-3-gallate, and berberine, on NF-κB signaling in muscle-derived cancers. These compounds have been shown to inhibit NF-κB signaling in rhabdomyosarcoma cells through various mechanisms, such as inhibiting the activation of the IKK complex and the NF-κB transcription factor. These findings suggest that natural compounds could be potential therapeutic agents for muscle-derived cancers. However, further research is needed to fully understand their mechanisms of action and potential clinical applications.

Resveratrol and Malignancies

Carcinogenesis is a multifactorial process, frequently encompassing 3 stages: initiation, promotion and progression. It is characterized by multiple deviations from normal both at the cell and organism levels. Although most people have a small number of cells that present deviations from normal, most of those cells will not cause cancer. However, some will. What tips the balance between normal and abnormal is the subject of intense scientific research as well as unfounded speculations. Chronic inflammation is one of the risk factors for cancer. Resveratrol is consumed by the population as a dietary supplement in the hope of decreasing the risk of inflammation and cancer and other chronic diseases such as diabetes and vascular diseases. There is a discrepancy between the doses used in the animal studies showing that resveratrol decreases all three stages of carcinogenesis, and the doses ingested by the population either as supplements or in the diet. While there is health benefit from using high resveratrol doses, it might be also of practical and scientific benefit to focus future effort in understanding the effects of normal dietary resveratrol levels.

A Resveratrol Analogue Promotes ERKMAPK-Dependent Stat3 Serine and Tyrosine Phosphorylation Alterations and Antitumor Effects In Vitro against Human Tumor Cells

(E)-4-(3,5-dimethoxystyryl)phenyl acetate (Cmpd1) is a resveratrol analog that preferentially inhibits glioma, breast, and pancreatic cancer cell growth, with IC50 values of 6-19 μM. Notably, the human U251MG glioblastoma tumor line is the most sensitive, with an IC50 of 6.7 μM, compared with normal fibroblasts, which have an IC50 > 20 μM. Treatment of U251MG cells that harbor aberrantly active signal transducer and activator of transcription (Stat) 3 with Cmpd1 suppresses Stat3 tyrosine705 phosphorylation in a dose-dependent manner in parallel with the induction of pserine727 Stat3 and extracellular signal-regulated kinase/mitogen-activated protein kinase 1/2 (pErk1/2(MAPK)). Inhibition of pErk1/2(MAPK) induction by the mitogen-activated protein/extracellular signal-regulated kinase kinase inhibitor PD98059 [2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one] blocked both the pserine727 Stat3 induction and ptyrosine705 Stat3 suppression by Cmpd1, indicating dependency on the mitogen-activated protein/extracellular signal-regulated kinase kinase-Erk1/2(MAPK) pathway for Cmpd1-induced modulation of Stat3 signaling. Cmpd1 also blocked epidermal growth factor-stimulated pStat1 induction, whereas upregulating pSrc, pAkt, p-p38, pHeat shock protein 27, and pmammalian target of rapamycin levels. However, pJanus kinase 2 and pEpidermal growth factor receptor levels were not significantly altered. Treatment of U251MG cells with Cmpd1 reduced in vitro colony formation, induced cell cycle arrest in the G2/M phase and cleavage of caspases 3, 8, and 9 and poly(ADP ribose) polymerase, and suppressed survivin, myeloid cell leukemia 1, Bcl-xL, cyclin D1, and cyclin B1 expression. Taken together, these data identify a novel mechanism for the inhibition of Stat3 signaling by a resveratrol analog and suggest that the preferential growth inhibitory effects of Cmp1 occur in part by Erk1/2(MAPK)-dependent modulation of constitutively active Stat3.

Proteomic profiling reveals that resveratrol inhibits HSP27 expression and sensitizes breast cancer cells to doxorubicin therapy

The use of chemopreventive natural compounds represents a promising strategy in the search for novel therapeutic agents in cancer. Resveratrol (3,4′,5-trans-trihydroxystilbilene) is a dietary polyphenol found in fruits, vegetables and medicinal plants that exhibits chemopreventive and antitumor effects. In this study, we searched for modulated proteins with preventive or therapeutic potential in MCF-7 breast cancer cells exposed to resveratrol. Using two-dimensional electrophoresis we found significant changes (FC >2.0; p≤0.05) in the expression of 16 proteins in resveratrol-treated MCF-7 cells. Six down-regulated proteins were identified by tandem mass spectrometry (ESI-MS/MS) as heat shock protein 27 (HSP27), translationally-controlled tumor protein, peroxiredoxin-6, stress-induced-phosphoprotein-1, pyridoxine-5′-phosphate oxidase-1 and hypoxanthine-guanine phosphoribosyl transferase; whereas one up-regulated protein was identified as triosephosphate isomerase. Particularly, HSP27 overexpression has been associated to apoptosis inhibition and resistance of human cancer cells to therapy. Consistently, we demonstrated that resveratrol induces apoptosis in MCF-7 cells. Apoptosis was associated with a significant increase in mitochondrial permeability transition, cytochrome c release in cytoplasm, and caspases -3 and -9 independent cell death. Then, we evaluated the chemosensitization effect of increasing concentrations of resveratrol in combination with doxorubicin anti-neoplastic agent in vitro. We found that resveratrol effectively sensitize MCF-7 cells to cytotoxic therapy. Next, we evaluated the relevance of HSP27 targeted inhibition in therapy effectiveness. Results evidenced that HSP27 inhibition using RNA interference enhances the cytotoxicity of doxorubicin. In conclusion, our data indicate that resveratrol may improve the therapeutic effects of doxorubicin in part by cell death induction. We propose that potential modulation of HSP27 levels using natural alternative agents, as resveratrol, may be an effective adjuvant in breast cancer therapy.

Resveratrol regulates human adipocyte number and function in a Sirt1-dependent manner

BACKGROUND

Caloric restriction leads to retardation of the aging processes and to longer life in many organisms. This effect of caloric restriction can be mimicked by resveratrol, a natural plant product present in grapes and red wine, which is known as a potent activator of sirtuin 1 [silent mating type information regulation 2 homolog 1 (Sirt1)].

OBJECTIVES

One main effect of caloric restriction in mammals is a reduction of body fat from white adipose tissue. We sought to identify the effects of resveratrol on fat cell biology and to elucidate whether Sirt1 is involved in resveratrol-mediated changes.

DESIGN

Human Simpson-Golabi-Behmel syndrome preadipocytes and adipocytes were used to study proliferation, adipogenic differentiation, glucose uptake, de novo lipogenesis, and adipokine secretion. Sirt1-deficient human preadipocytes were generated by using a lentiviral small hairpin RNA system to study the role of Sirt1 in resveratrol-mediated changes.

RESULTS

Resveratrol inhibited preadipocyte proliferation and adipogenic differentiation in a Sirt1-dependent manner. In human adipocytes, resveratrol stimulated basal and insulin-stimulated glucose uptake. De novo lipogenesis was inhibited in parallel with a down-regulation of lipogenic gene expression. Furthermore, resveratrol down-regulated the expression and secretion of interleukin-6 and interleukin-8. Sirt1 was only partially responsible for the regulation of resveratrol-mediated changes in adipokine secretion.

CONCLUSIONS

Taken together, our data suggest that resveratrol influences adipose tissue mass and function in a way that may positively interfere with the development of obesity-related comorbidities. Thus, our findings open up the new perspective that resveratrol-induced intracellular pathways could be a target for prevention or treatment of obesity-associated endocrine and metabolic adverse effects.

Multiple molecular targets of resveratrol: Anti-carcinogenic mechanisms

Plant-derived polyphenolic compounds, such as the stilbene resveratrol (trans-3,4',5-trihydroxystilbene), have been identified as potent anti-cancer agents. Extensive in vitro studies revealed multiple intracellular targets of resveratrol, which affect cell growth, inflammation, apoptosis, angiogenesis, and invasion and metastasis. These include tumor suppressors p53 and Rb; cell cycle regulators, cyclins, CDKs, p21WAF1, p27KIP and INK and the checkpoint kinases ATM/ATR; transcription factors NF-kappaB, AP-1, c-Jun, and c-Fos; angiogenic and metastatic factors, VEGF and matrix metalloprotease 2/9; cyclooxygenases for inflammation; and apoptotic and survival regulators, Bax, Bak, PUMA, Noxa, TRAIL, APAF, survivin, Akt, Bcl2 and Bcl-X(L). In addition to its well-documented anti-oxidant properties, there is increasing evidence that resveratrol exhibits pro-oxidant activity under certain experimental conditions, causing oxidative DNA damage that may lead to cell cycle arrest or apoptosis. This review summarizes in vitro mechanistic data available for resveratrol and discusses new potential anti-cancer targets and the antiproliferative mechanisms of resveratrol.

Resveratrol-induced growth inhibition in MDA-MB-231 breast cancer cells is associated with mitogen-activated protein kinase signaling and protein translation

Resveratrol (3,4',5-trans-trihydroxystilbene) is a natural compound found in grapes and several medicinal plants and has been shown to have anticancer effects on various human cancer cells. The aim of this study was to further investigate the molecular mechanism of this anticancer effect. Resveratrol effect on cell growth, morphology and gene expression was investigated in estrogen receptor-negative MDA-MB-231 human breast cancer cell line. We show here that resveratrol-induced growth inhibition in the estrogen receptor negative MDA-MB-231 breast cancer cells is due to the induction of apoptosis as demonstrated by morphological, nuclear staining and PARP cleavage analysis. Resveratrol-induced growth inhibition was associated with transient activation of p44/42 mitogen-activated protein kinase (MAPK) (Thr202/Tyr204). Most importantly, resveratrol inhibited both the phosphorylation at Ser240/244 and the expression of the pS6 ribosomal protein. This protein is known to play an important role in the translation of mRNAs that have oligopyrimidine tracts in their 5' untranslated regions. Interestingly, only MAPK inhibitor was able to block resveratrol-induced growth inhibition suggesting that effects of resveratrol on cell growth are dependent on MAPK signaling. The data demonstrated that resveratrol-induced apoptosis is associated with MAPK signaling and with the inhibition of proteins that are involved in protein translation. This is the first data linking resveratrol with downregulation of protein translation via p44/42 MAPK and S6 ribosomal protein. We propose to use these proteins as predictive biomarkers to evaluate the treatment efficacy of resveratrol in estrogen receptor-negative human breast cancer.

Resveratrol inhibits cell growth and induces apoptosis of rat C6 glioma cells

Resveratrol (Res) has been reported to inhibit tumor initiation, promotion, and progression in a variety of cell culture systems depending on the specific cell type and cellular environment. In the present study, we determined the effect of Res on the cell growth and apoptosis of rat glioma C6 cell line as well as mouse fibroblast 3T3 cell line, in vitro. Concurrently, we investigated whether caspase-3 is involved in the Res-induced apoptosis of rat glioma cells. Exposure to Res exhibits a significant anti-proliferative effect and induces an increase in the population of apoptotic cells on C6 cells in a concentration- and time-dependent manner, but not for normal 3T3 fibroblast cells, as measured by methyl thiazolyl tetrazolium assay and flow cytometer. Distinguished increase of C6 cells in S phase is observed after the treatment of Res as compared to insignificant change in cell cycle distribution of 3T3 cells. TdT-mediated dUTP nick end labeling fluorescence staining, HE staining, and scanning electron microscope revealed abnormal morphology and ultrastructure in C6 cells treated with Res. Our data showed that Res can increase the expression and induced the activation of caspase-3 in rat glioma C6 cells. These results suggest that Res has significant apoptosis-inducing effect on C6 glioma cells other than normal fibroblast 3T3 cells in vitro and caspase-3 may act as a potential mediator in the process.