Resveratrol inhibits hypoxia-induced accumulation of hypoxia-inducible factor-1alpha and VEGF expression in human tongue squamous cell carcinoma and hepatoma cells

Cinnamon extract reduces VEGF expression via suppressing HIF-1α gene expression and inhibits tumor growth in mice

Although many anti-VEGF agents are available for cancer treatment, side effects of these agents limit their application for cancer treatment and prevention. Here we studied the potential use of a diet-based agent as an inhibitor for VEGF production. Using a VEGF reporter assay, our data showed that an extract from cinnamon (CE) was a potent inhibitor of VEGF production in human cancer cells and suggested inhibition might be mediated through the suppression of HIF-1α gene expression and protein synthesis. Furthermore, CE treatment was found to inhibit expression and phosphorylation of STAT3 and AKT, which are key factors in the regulation of HIF-1α expression, and significantly reduce angiogenesis potential of cancer cells by migration assay. Consistent with these results, we observed significant suppression of VEGF expression, blood vessel formation, and tumor growth in a human ovarian tumor model in mice treated with CE. Cinnamaldehyde, a major component in cinnamon, was identified as one active component in CE that inhibits VEGF expression. Taken together, our findings provide a novel mechanism underlying anti-angiogenic and anti-tumor actions of CE and support the potential use of CE in cancer prevention and treatment. © 2016 Wiley Periodicals, Inc.

Resveratrol inhibits hyperglycemia-driven ROS-induced invasion and migration of pancreatic cancer cells via suppression of the ERK and p38 MAPK signaling pathways

Increasing evidence suggests that there is a strong relationship between diabetes mellitus (DM) and pancreatic cancer. Our previous study revealed that hyperglycemia could enhance the invasive and migratory activities of pancreatic cancer cells. Resveratrol, a natural polyphenolic phytoalexin, has many biological and pharmaceutical properties, including antioxidant and anti-tumorigenic capabilities. The aim of the present study was to evaluate whether resveratrol affects hyperglycemia-induced reactive oxygen species (ROS) production as well as the invasion and migration of pancreatic cancer and its underlying mechanisms. Human pancreatic cancer Panc-1 cells were exposed to high glucose condition with or without resveratrol, N-acetylcysteine (NAC, a scavenger of free radicals), PD 98059 (an ERK inhibitor) or SB 203580 (a p38 MAPK inhibitor). The intracellular ROS and hydrogen peroxide (H2O2) were determined using 2,7-dichlorodihydrofluorecein diacetate and H2O2 assay. MTT, wound healing assay and transwell matrigel invasion assay were used to detect the proliferation, migration and invasion potential of cancer cells. The expressions of uPA, E-cadherin and Glut-1 were examined using QT-PCR and western blot analysis at mRNA and protein levels. The activation of p-ERK, p-p38 and p-NF-κB were measured by western blot analysis. The results of the present study showed that resveratrol could significantly decrease high glucose-induced production of ROS and H2O2 in Panc-1 cells. Resveratrol was also able to inhibit high glucose-induced proliferation, migration and invasion of pancreatic cancer cells. High glucose-modulated expression of uPA, E-cadherin and Glut-1 were inhibited by resveratrol. In addition, high glucose-induced activation of ERK and p38 MAPK signaling pathways as well as the transcription factor NF-κB could also be suppressed by resveratrol. Furthermore, resveratrol was able to suppress H2O2-induced migration and invasion abilities of pancreatic cancer cells. Taken together, these data indicate that resveratrol plays an important role in suppressing hyperglycemia-driven ROS-induced pancreatic cancer progression by inhibiting the ERK and p38 MAPK signaling pathways, providing evidence that resveratrol might be a potential candidate for chemoprevention of pancreatic cancer.

Preventive and Therapeutic Effects of Chinese Herbal Compounds against Hepatocellular Carcinoma

Traditional Chinese Medicines, unique biomedical and pharmaceutical resources, have been widely used for hepatocellular carcinoma (HCC) prevention and treatment. Accumulated Chinese herb-derived compounds with significant anti-cancer effects against HCC have been identified. Chinese herbal compounds are effective in preventing carcinogenesis, inhibiting cell proliferation, arresting cell cycle, inducing apoptosis, autophagy, cell senescence and anoikis, inhibiting epithelial-mesenchymal transition, metastasis and angiogenesis, regulating immune function, reversing drug resistance and enhancing the effects of chemotherapy in HCC. This paper comprehensively reviews these compounds and their effects on HCC. Finally, the perspectives and rational application of herbal compounds for HCC management are discussed.

Effects of resveratrol and methoxyamine on the radiosensitivity of iododeoxyuridine in U87MG glioblastoma cell line

The purpose of this study was to evaluate the combination effect of resveratrol and methoxyamine on radiosensitivity of iododeoxyuridine in spheroid culture of U87MG glioblastoma cell line using colony formation and alkaline comet assays. Spheroids on day-20 with 350 µm diameters were treated with 20 µM resveratrol and/or 6 mM methoxyamine and/or 1 µM iododeoxyuridine for one volume doubling time (67 h), and then irradiated with 2 Gy gamma-radiation ((60)Co) in different groups. After treatment, viability of the cells, colony forming ability and DNA damages were obtained by blue dye exclusion, colony formation and alkaline comet assay, respectively. Our results showed that methoxyamine and resveratrol could significantly reduce colony number and induce the DNA damages of glioblastoma spheroid cells treated with iododeoxyuridine in combination with gamma-rays. Therefore, methoxyamine as base excision repair inhibitor and resveratrol as hypoxia inducible factor 1-alpha inhibitor in combination with iododeoxyuridine as radiosensitizer enhanced the radiosensitization of glioblastoma spheroid cells.

Inhibition of hypoxia-inducible factor via upregulation of von Hippel-Lindau protein induces "angiogenic switch off" in a hepatoma mouse model

“Angiogenic switch off” is one of the ideal therapeutic concepts in the treatment of cancer. However, the specific molecules which can induce “angiogenic switch off” in tumor have not been identified yet. In this study, we focused on von Hippel-Lindau protein (pVHL) in hepatocellular carcinoma (HCC) and investigated the effects of sulfoquinovosyl-acylpropanediol (SQAP), a novel synthetic sulfoglycolipid, for HCC. We examined mutation ratio of VHL gene in HCC using 30 HCC samples and we treated the HCC-implanted mice with SQAP. Thirty clinical samples showed no VHL genetic mutation in HCC. SQAP significantly inhibited tumor growth by inhibiting angiogenesis in a hepatoma mouse model. SQAP induced tumor “angiogenic switch off” by decreasing hypoxia-inducible factor (HIF)-1, 2α protein via pVHL upregulation. pVHL upregulation decreased HIFα protein levels through different multiple mechanisms: (i) increasing pVHL-dependent HIFα protein degradation; (ii) decreasing HIFα synthesis with decrease of NF-κB expression; and (iii) decrease of tumor hypoxia by vascular normalization. We confirmed these antitumor effects of SQAP by the loss-of-function experiments. We found that SQAP directly bound to and inhibited transglutaminase 2. This study provides evidence that upregulation of tumor pVHL is a promising target, which can induce “angiogenic switch off” in HCC.

Resveratrol Inhibits Hypoxia-Induced Vascular Endothelial Growth Factor Expression and Pathological Neovascularization

PURPOSE

To investigate the effects of resveratrol on the expression of hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) in human adult retinal pigment epithelial (ARPE-19) cells, and on experimental choroidal neovascularization (CNV) in mice.

MATERIALS AND METHODS

ARPE-19 cells were treated with different concentrations of resveratrol and then incubated under hypoxic conditions with subsequent evaluation of cell viability, expression of HIF-1α, and expression of VEGF. The effects of resveratrol on the synthesis and degradation of hypoxia-induced HIF-1α were evaluated using inhibitors of the PI3K/Akt/mTOR and the ubiquitin proteasome pathways. In animal studies, CNV lesions were induced in C57BL/6 mice by laser photocoagulation. After 7 days of oral administration of resveratrol or vehicle, which began one day after CNV induction, image analysis was used to measure CNV areas on choroidal flat mounts stained with isolectin IB4.

RESULTS

In ARPE-19 cells, resveratrol significantly inhibited HIF-1α and VEGF in a dose-dependent manner, by blocking the PI3K/Akt/mTOR signaling pathway and by promoting proteasomal HIF-1α degradation. In mice experiments, orally administered resveratrol significantly inhibited CNV growth in a dose-dependent manner.

CONCLUSION

Resveratrol may have therapeutic value in the management of diseases involving pathological neovascularization.

Resveratrol attenuates norepinephrine-induced ovarian cancer invasiveness through downregulating hTERT expression

Stress hormone norepinephrine (NE) has been associated with acquisition of cancer progression, and naturally occurring phytoalexin resveratrol (REV) has been known to suppress cancer growth and progression. In the present study, we determine the effect of REV on NE-induced ovarian cancer invasiveness. Pretreatment of REV significantly inhibited NE-induced ovarian cancer cell epithelial-to-mesenchymal transition with concomitant recovery of E-cadherin expression. In addition, our data showed that REV downregulates NE-induced human telomerase reverse transcriptase (hTERT) expression through inhibiting Src phosphorylation and HIF-1α expression. Further, REV reduced NE-induced Slug expression and subsequent ovarian cancer invasion. More importantly, combined treatment of REV with a pharmacological inhibitor of beta adrenergic receptor significantly attenuated NE-induced ovarian cancer invasion compared to single treatment. Therefore, we demonstrate interference of a Src and HIF-1α/hTERT/Slug signaling cascade by REV, providing potential therapeutic targets and inhibition of ovarian cancer.

Targeting protein-protein interactions (PPIs) of transcription factors: Challenges of intrinsically disordered proteins (IDPs) and regions (IDRs)

In this review we discuss recent progress in targeting the protein-protein interactions made by oncogenic transcription factors. We particularly focus on the challenges posed by the prevalence of intrinsically disordered regions in this class of protein and the strategies being used to overcome them.

Resveratrol reduces the hypoxia-induced resistance to doxorubicin in breast cancer cells

Resveratrol (3,4',5-trihydroxy-trans-stilbene) is known to enhance the cytotoxicity of the anticancer drug doxorubicin. On the other hand, breast cancer MCF-7 cells acquire resistance to doxorubicin under hypoxic conditions. In this study, we investigated the effect of resveratrol on hypoxia-induced resistance to doxorubicin in MCF-7 cells. Resveratrol and its derivative 3,5-dihydroxy-4'-methoxy-trans-stilbene, but not 3,5-dimethoxy-4'-hydroxy-trans-stilbene, cancelled hypoxia-induced resistance to doxorubicin at a concentration of 10 μM. Carbonyl reductase 1 (CBR1) catalyzes the conversion of doxorubicin to its metabolite doxorubicinol, which is much less effective than doxorubicin. Hypoxia increased the expression of CBR1 at both mRNA and protein levels, and knockdown of CBR1 inhibited hypoxia-induced resistance to doxorubicin in MCF-7 cells. Knockdown of hypoxia-inducible factor (HIF)-1α repressed the hypoxia-induced expression of CBR1. Resveratrol repressed the expression of HIF-1α protein, but not HIF-1α mRNA, and decreased hypoxia-activated HIF-1 activity. Resveratrol repressed the hypoxia-induced expression of CBR1 at both mRNA and protein levels. Likewise, 3,5-dihydroxy-4'-methoxy-trans-stilbene decreased the hypoxia-induced expression of CBR1 protein, but not 3,5-dimethoxy-4'-hydroxy-trans-stilbene. Furthermore, resveratrol decreased the expression of HIF-1α protein even in the presence of the proteasome inhibitor MG132 in hypoxia. Theses results indicate that in MCF-7 cells, HIF-1α-increased CBR1 expression plays an important role in hypoxia-induced resistance to doxorubicin and that resveratrol and 3,5-dihydroxy-4'-methoxy-trans-stilbene decrease CBR1 expression by decreasing HIF-1α protein expression, perhaps through a proteasome-independent pathway, and consequently repress hypoxia-induced resistance to doxorubicin.

Resveratrol-loaded polymeric nanoparticles suppress glucose metabolism and tumor growth in vitro and in vivo

Resveratrol (RSV) is a natural phenol with promising anti-tumor activities, but its use for in vivo cancer treatment is limited by low aqueous solubility and poor stability. In this study, we prepared RSV-loaded polyethylene glycol-polylactic acid (PEG-PLA; M.W. 5000-5000) polymer nanoparticles (NPs) for improved stability and controlled delivery, and investigated its metabolic and anti-tumor effect in vitro and in vivo. CT26 colon cancer cells displayed significantly reduced cell number to 5.6% and colony forming capacity to 6.3% of controls by 72 h treatment with 40 and 20 μM of RSV-NP, respectively. Flow cytometry and western blots demonstrated increased apoptotic cell death, and (18)F FDG uptake and reactive oxygen species was significantly reduced by RSV-NP. All of these effects were comparable to or greater in potency compared to free RSV. When RSV-NP was intravenously administered to CT26 tumor bearing mice, there was a reduction of (18)F FDG uptake on PET/CT by day 4. Longer treatment led to retardation of tumor growth accompanied by an improvement in survival compared to empty NP-injected controls. These results demonstrate that the in vitro and in vivo metabolic and anti-tumor effects of RSV is preserved by PEG-PLA NP loading, and provide an encouraging outlook on the potential of polymeric NPs as an effective method to deliver RSV for cancer therapy.

Resveratrol abrogates the effects of hypoxia on cell proliferation, invasion and EMT in osteosarcoma cells through downregulation of the HIF-1α protein

Resveratrol has been shown to have antineoplastic effects in vivo and in vitro. However, the effect of resveratrol on the hypoxia-enhanced proliferation and invasion of osteosarcoma cells remains unclear. In this study, we investigated the role of resveratrol on regulating proliferation and invasion of osteosarcoma cells under hypoxic conditions. Saos-2 cells were cultured under controlled hypoxic conditions (3% O2) or normoxic conditions. Resveratrol (50 µM) was added in the medium, and hypoxia inducible factor-1α (HIF-1α) siRNA was used to inhibit HIF-1α transcription. Proliferation of Saos-2 cells was evaluated by the methabenzthiazuron (MTT) assay. The invasive ability of Saos-2 cells was determined by a Transwell assay. HIF-1α, E-cadherin and vimentin protein levels were detected by western blot analysis. HIF-1α, E-cadherin and vimentin mRNA levels were assessed by RT-PCR. Compared to the control group, hypoxia significantly increased the proliferation rate and invasive ability of Saos-2 cells. Moreover, hypoxia markedly increased the E-cadherin level and decreased vimentin expression. However, resveratrol or HIF-1α silencing reverted all the above effects of hypoxia in Saos-2 cells. Moreover, resveratrol inhibited HIF-1α protein accumulation without affecting the HIF-1α mRNA level. These data suggest that resveratrol can inhibit the hypoxia‑enhanced proliferation, invasion and epithelial to mesenchymal transition process in osteosarcoma via downregulation of the HIF-1α protein. Thus, HIF-1α may be a promising drug target of resveratrol in the context of development of anticancer therapy for human osteosarcoma.

Anticancer mechanisms of resveratrol in liver cancer

Primary liver cancer is one of the most common malignant tumors. Because primary liver cancer has a high degree of malignancy and the early diagnosis is very difficult, it has a very poor prognosis and is associated with high mortality. Resveratrol is found in a variety of natural plants. Recent studies found that resveratrol has significant effects against liver cancer cells in vivo without obvious side effect, so it may become one of the most promising anticancer agents. This article will review the advances in understanding the anticancer mechanisms of resveratrol in liver cancer.

Estrogen receptor-mediated resveratrol actions on blood-brain barrier of ovariectomized mice

To test whether resveratrol provides benefits via estrogen receptors (ERs) in the blood-brain barrier of estrogen-deficient females, ovariectomized mice were treated with resveratrol then were subjected to transient middle cerebral artery occlusion (MCAO). Compared with vehicle treatment, resveratrol reduced infarct volume and neurologic deficits after MCAO. Basal tight junction (TJ) protein levels in the brain were increased by resveratrol. After MCAO, blood-brain barrier breakdown reduced levels of TJ proteins, and induction of HIF-1α and VEGF were attenuated by resveratrol. These effects were reversed by the ERs antagonist, ICI182,780. In mouse brain, endothelial cells (bEnd.3) exposed to hypoxia, resveratrol treatment protected the cells against cytotoxicity, increases of paracellular permeability and changes in levels of TJ protein and HIF-1α/VEGF proteins. These effects were reversed by ICI182,780 but not by specific ERα or ERβ antagonists, indicating nonspecific ER mediated effects. Altogether, these results showed that neuroprotective effects of resveratrol in ovariectomized mice were mediated by ERs and associated with tightening of blood-brain barrier, suggesting that resveratrol can be an alternative to estrogens to protect the brains of estrogen-deficient females against ischemic insult.

The suppressive effect of resveratrol on HIF-1α and VEGF expression after warm ischemia and reperfusion in rat liver

Background

Hypoxia-inducible factor-1α (HIF-1α) is overexpressed in many human tumors and their metastases, and is closely associated with a more aggressive tumor phenotype. The aim of the present study was to investigate the effect of resveratrol (RES) on the expression of ischemic-induced HIF-1α and vascular endothelial growth factor (VEGF) in rat liver.

Methods

Twenty-four rats were randomized into Sham, ischemia/reperfusion (I/R), and RES preconditioning groups. I/R was induced by portal pedicle clamping for 60 minutes followed by reperfusion for 60 minutes. The rats in RES group underwent the same surgical procedure as I/R group, and received 20 mg/kg resveratrol intravenously 30 min prior to ischemia. Blood and liver tissue samples were collected and subjected to biochemical assays, RT-PCR, and Western blot assays.

Results

I/R resulted in a significant (P<0.05) increase in liver HIF-1α and VEGF at both mRNA and protein levels 60 minutes after reperfusion. The mRNA and protein expressions of HIF-1α and VEGF decreased significantly in RES group when compared to I/R group (P<0.05).

Conclusion

The inhibiting effect of RES on the expressions of HIF-1α and VEGF induced by I/R in rat liver suggested that HIF-1α/VEGF could be a promising drug target for RES in the development of an effective anticancer therapy for the prevention of hepatic tumor growth and metastasis.

Roles of PI3K/Akt and c-Jun signaling pathways in human papillomavirus type 16 oncoprotein-induced HIF-1α, VEGF, and IL-8 expression and in vitro angiogenesis in non-small cell lung cancer cells

Background and Objectives

Human papillomavirus (HPV)-16 infection may be related to non-smoking associated lung cancer. Our previous studies have found that HPV-16 oncoproteins promoted angiogenesis via enhancing hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), and interleukin-8 (IL-8) expression in non-small cell lung cancer (NSCLC) cells. In this study, we further investigated the roles of PI3K/Akt and c-Jun signaling pathways in it.

Methods

Human NSCLC cell lines, A549 and NCI-H460, were stably transfected with pEGFP-16 E6 or E7 plasmids. Western blotting was performed to analyze the expression of HIF-1α, p-Akt, p-P70S6K, p-P85S6K, p-mTOR, p-JNK, and p-c-Jun proteins. VEGF and IL-8 protein secretion and mRNA levels were determined by ELISA and Real-time PCR, respectively. The invitro angiogenesis was observed by human umbilical vein endothelial cells (HUVECs) tube formation assay. Co-immunoprecipitation was performed to analyze the interaction between c-Jun and HIF-1α.

Results

HPV-16 E6 and E7 oncoproteins promoted the activation of Akt, P70S6K, P85S6K, mTOR, JNK, and c-Jun. LY294002, a PI3K inhibitor, inhibited HPV-16 oncoprotein-induced activation of Akt, P70S6K, and P85S6K, expression of HIF-1α, VEGF, and IL-8, and invitro angiogenesis. c-Jun knockdown by specific siRNA abolished HPV-16 oncoprotein-induced HIF-1α, VEGF, and IL-8 expression and invitro angiogenesis. Additionally, HPV-16 oncoproteins promoted HIF-1α protein stability via blocking proteasome degradation pathway, but c-Jun knockdown abrogated this effect. Furthermore, HPV-16 oncoproteins increased the quantity of c-Jun binding to HIF-1α.

Conclusions

PI3K/Akt signaling pathway and c-Jun are involved in HPV-16 oncoprotein-induced HIF-1α, VEGF, and IL-8 expression and invitro angiogenesis. Moreover, HPV-16 oncoproteins promoted HIF-1α protein stability possibly through enhancing the interaction between c-Jun and HIF-1α, thus making a contribution to angiogenesis in NSCLC cells.

Identification of carbonyl reductase 1 as a resveratrol-binding protein by affinity chromatography using 4'-amino-3,5-dihydroxy-trans-stilbene

The mechanisms by which resveratrol (3,4',5-trihydroxy-trans-stilbene) elicits diverse health benefits remain unclear because the intracellular target molecules of resveratrol are poorly defined. We screened resveratrol-binding proteins from lysates of MCF-7 breast cancer cells using resveratrol-affinity resin, which was constructed by immobilizing 4'-amino-3,5-dihydroxy-trans-stilbene on activated CH-Sepharose. On SDS-PAGE, two bands were detected as proteins that specifically bound to the resveratrol-affinity resin. One of these, a 30-kDa protein, was identified as human carbonyl reductase 1 (CBR1) by hybrid linear ion trap/time-of-flight mass spectrometry. Similarly, recombinant CBR1 bound to the resveratrol-affinity resin in the absence of resveratrol, but not in the presence of resveratrol. Among its activities, CBR1 catalyzes a NADPH-dependent reduction of the anticancer drug doxorubicin to the cardiotoxin doxorubicinol. The effects of doxorubicin on viability of MCF-7 cells were enhanced by resveratrol, 3,5-dihydroxy-4'-methoxy-trans-stilbene, 3,4'-dihydroxy-5-methoxy-trans-stilbene, and 4'-amino-3,5-dihydroxy-trans-stilbene at concentrations of 1 and 10 μM. Resveratrol and these derivatives inhibited CBR1 activities to a similar degree at concentrations of 100 and 200 μM. However, 3,5-dimethoxy-4'-hydroxy-trans-stilbene and m-hydroquinone had no influence on doxorubicin cytotoxicity or CBR1 activity. Resveratrol inhibited CBR1 activity through an apparent mix of competitive (Ki=55.8 μM) and noncompetitive (αKi=164 μM; α=2.98) inhibition kinetics. These results indicate that (i) resveratrol enhances the cytotoxic effects of doxorubicin on MCF-7 cells; (ii) the moiety that contains the 3,5-dihydroxyl groups of resveratrol, but not the m-hydroquinone structure alone, is required to bind CBR1; and (iii) resveratrol acts as a mixed-type inhibitor of CBR1 activity on doxorubicin.

Tumor microenvironment in head and neck squamous cell carcinoma

The tumor microenvironment (TME) of head and neck squamous cell carcinoma (HNSCC) is comprised of cancer-associated fibroblasts (CAFs), immune cells, and other supporting cells. Genetic changes in the carcinoma cells, such as alterations to TP53, NOTCH1, and specific gene expression profiles, contribute to derangements in cancer and microenvironment cells such as increased ROS, overproduction of cytokines, and epithelial to mesenchymal transition (EMT). CAFs are among the most critical elements of the TME contributing to proliferation, invasion, and metastasis. The adaptive immune response is suppressed in HNSCC through overexpression of cytokines, triggered apoptosis of T cells, and alterations in antigen processing machinery. Overexpression of critical cytokines, such as transforming growth factor-β (TGF-β), contributes to EMT, immune suppression, and evolution of CAFs. Inflammation and hypoxia are driving forces in angiogenesis and altered metabolism. HNSCC utilizes glycolytic and oxidative metabolism to fuel tumorigenesis via coupled mechanisms between cancer cell regions and cells of the TME. Increased understanding of the TME in HNSCC illustrates that the long-held notion of "condemned mucosa" reflects a process that extends beyond the epithelial cells to the entire tissue comprised of each of these elements.

Resveratrol attenuates diabetic nephropathy via modulating angiogenesis

Angiogenesis plays an important role in the pathogenesis of diabetic nephropathy (DN). In the present study, we investigated the therapeutic potential of resveratrol, a polyphenol with antiangiogenic activity in DN. In a type 1 diabetic rat model, resveratrol treatment blunted the increases of urine albumin excretion, kidney weight and creatinine clearance rate. The increases of glomerular diameter, mesangium accumulation, glomerular basement membrane thickness and renal fibrosis in diabetic rats were also reduced by resveratrol treatment. In the diabetic kidney, increased expression of vascular endothelial growth factor (VEGF), Flk-1 and angiopoietin 2, and reduced expression of Tie-2 were observed. These changes in angiogenic hormones and associated receptors were attenuated by resveratrol treatment. No changes in angiopoietin 1 expression were detected among each group of rats. Resveratrol also significantly downregulated high glucose-induced VEGF and Flk-1 expressions in cultured mouse glomerular podocytes and endothelial cells, respectively. These effects were attenuated by knocking-down silent information regulator 1 (Sirt1) expression. In contrast, upregulation of Sirt1 in cultured endothelial cells reduced Flk-1 expression. Increased permeability and cellular junction disruption of cultured endothelial cells caused by VEGF were also inhibited by resveratrol pretreatment. Taken together, the present study demonstrated that resveratrol may attenuate DN via modulating angiogenesis.

Role of the hypoxia response pathway in lens formation during embryonic development of Xenopus laevis

The RING finger ubiquitin ligase seven in absentia homolog 2 (Siah2) was identified in the R7 photoreceptor cells of Drosophila melanogaster, and it regulates the stability of prolyl hydroxylase domains (PHDs), with a concomitant effect on HIF-1α availability in the hypoxia response pathway. We previously reported that the hypoxia response pathway contributes to eye development during the embryonic development of Xenopus laevis. In this paper, the role of Siah2-mediated hypoxia response pathway in eye development of X. laevis embryos was further characterized. Xenopus Siah2 (xSiah2) mRNA was detected in lens tissue and xSiah2 overexpression caused a thickened lens placode, leading to loss of the optic lens. In embryos overexpressing xSiah2, lens marker gene transcription was reduced, suggesting that xSiah2 contributes to lens formation. xSiah2 overexpression decreased Xenopus PHD accumulation and increased Xenopus HIF-1α (xHIF-1α) accumulation. xHIF-1α degeneration with resveratrol restored the optical abnormality caused by xSiah2 overexpression, suggesting that the xSiah2-mediated hypoxia response pathway contributes to lens formation. Moreover, xSiah2 overexpression decreased endothelial–mesenchymal transition (EMT)-related Notch signaling-responsive genes transcription during the invasion of the lens placode. Our results suggest that the hypoxia response pathway plays an important role in the regulation of the EMT via the Notch signaling pathway during lens formation.

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The ubiquitin lyase Siah2 regulates HIF-1α availability in the hypoxia response pathway.

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xSiah2 overexpression causes loss of the lens of Xenopus laevis.

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xSiah2 mRNA is detected in the lens placode from embryonic stage 30.

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xHIF-1α overexpression at stage 38 causes loss of the lens of Xenopus laevis.

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xSiah2 overexpression suppresses endothelial–mesenchymal transition-related genes.

Chinese herbal medicine-derived compounds for cancer therapy: a focus on hepatocellular carcinoma

ETHNOPHARMACOLOGICAL RELEVANCE

Hepatocellular carcinoma (HCC) as the major histological subtype of primary liver cancer remains one of the most common malignancies worldwide. Due to the complicated molecular pathogenesis of HCC, the option for effective systemic treatment is quite limited. There exists a critical need to explore and evaluate possible alternative strategies for effective control of HCC. With a long history of clinical use, Chinese herbal medicine (CHM) is emerging as a noticeable choice for its multi-level, multi-target and coordinated intervention effects against HCC. With the aids of phytochemistry and molecular biological approaches, in the past decades many CHM-derived compounds have been carefully studied through both preclinical and clinical researches and have shown great potential in novel anti-HCC natural product development. The present review aimed at providing the most recent developments on anti-HCC compounds derived from CHM, especially their underlying pharmacological mechanisms.

MATERIALS AND METHODS

A systematic search of anti-HCC compounds from CHM was carried out focusing on literatures published both in English (PubMed, Scopus, Web of Science and Medline) and in Chinese academic databases (Wanfang and CNKI database).

RESULTS

In this review, we tried to give a timely and comprehensive update about the anti-HCC effects and targets of several representative CHM-derived compounds, namely curcumin, resveratrol, silibinin, berberine, quercetin, tanshinone II-A and celastrol. Their mechanisms of anti-HCC behaviors, potential side effects or toxicity and future research directions were discussed.

CONCLUSION

Herbal compounds derived from CHM are of much significance in devising new drugs and providing unique ideas for the war against HCC. We propose that these breakthrough findings may have important implications for targeted-HCC therapy and modernization of CHM.

A novel resveratrol analogue, HS-1793, inhibits hypoxia-induced HIF-1α and VEGF expression, and migration in human prostate cancer cells

In many studies, resveratrol has been shown to have a chemopreventive effect in various types of cancer cells. However, the biological activity of resveratrol is limited by its photosensitivity and metabolic instability. This study investigated the effects of a novel analogue of resveratrol, HS-1793, on the expression of HIF-1α and vascular endothelial growth factor (VEGF) in PC-3 human prostate cancer cells. Hypoxic condition induced HIF-1α protein level in PC-3 cells in a time-dependent manner, and treatment with HS-1793 markedly decreased HIF-1α expression levels. HS-1793 also inhibited VEGF level. Mechanistically, HS-1793 inhibited HIF-1α and VEGF expression through multiple mechanisms. Firstly, HS-1793 inhibited phosphorylation of PI3K and Akt in PC-3 cells. Furthermore, HS-1793 substantially induced HIF-1α protein degradation through the proteasome pathway. Finally, HS-1793 inhibited hypoxia-induced PC-3 cell migration. These data suggest that HS-1793 may inhibit human prostate cancer progression and angiogenesis by inhibiting the expression of HIF-1α and VEGF. Moreover, HS-1793 showed more potent effects than resveratrol on the cytotoxic effects on PC-3 cells. Taken together, these results implied that HS-1793, a novel analogue of resveratrol, may be a new potent chemopreventive agent against human prostate cancer cells.

HIFs, angiogenesis, and cancer

Tumor hypoxia was first described in the 1950s by radiation oncologists as a frequent cause of failure to radiotherapy in solid tumors. Today, it is evident that tumor hypoxia is a common feature of many cancers and the master regulator of hypoxia, hypoxia-inducible factor-1 (HIF-1), regulates multiple aspects of tumorigenesis, including angiogenesis, proliferation, metabolism, metastasis, differentiation, and response to radiation therapy. Although the tumor hypoxia response mechanism leads to a multitude of downstream effects, it is angiogenesis that is most crucial and also most susceptible to molecular manipulation. The delineation of molecular mechanisms of angiogenesis has revealed a critical role for HIF-1 in the regulation of angiogenic growth factors. In this article, we review what has been described about HIF-1: its structure, its regulation, and its implication for cancer therapy and we focus on its role in angiogenesis and cancer.

Resveratrol in prostate diseases - a short review

Introduction

Resveratrol is a plant–derived polyphenol suggested to have many beneficial health effects, including antioxidant, anti–inflammatory, anti–proliferative, proapoptotic, and anti–angiogenic. It is even specu- lated that uptake of resveratrol by red wine consumption could be behind the so–called French paradox the lower incidence of cardiovascular diseases in the French population. These properties, together with good absorption and tolerance, would make it an attractive agent in prostatic diseases, especially in cancer prevention and treatment.

Material and methods

MEDLINE search (keywords “prostate res- veratrol”) resulted in 39 research papers published since 2007. It has been shown that resveratol down–regulate androgen receptor expression, inhibit proliferation, and promote apop- tosis in prostate cancer cell lines and enhance their sensitivity to ionizing radiation. Several studies on animal prostate cancer development also suggest that resveratrol is able do delay or prevent carcino- genesis in prostate. Despite these promising results, there is no proof of any therapeutic properties of resveratrol in prostate diseases from human clinical trials nor any information about ongoing trials in this field.

Conclusions

Resveratrol is produced and sold as a nutritional supplement, there is not enough clinical evidence to justify a recommendation for the administration of resveratrol in humans at present.

Recent agents targeting HIF-1α for cancer therapy

The discovery of hypoxia-inducible factor-1 (HIF-1) has led to an increasing understanding of the mechanism of tumor hypoxia in the past two decades. As a key transcriptional regulator, HIF-1 plays a central role in the adaptation of tumor cells to hypoxia by activating the transcription of targeting genes, which regulate several biological processes including angiogenesis, cell proliferation, survival, glucose metabolism and migration. The inhibitors of HIF-1 in cancer have provided us a new clue for the targeting cancer therapy. This review will introduce the general knowledge of the biology characteristic of HIF-1 and mechanism of O(2)-dependent regulation. Moreover, a number of chemical inhibitors plus protein and nucleic acid inhibitors are included and classified mainly based on their different mechanism of inhibiting action. We also prefer to discuss the advantages of protein and nucleic acid inhibitors compared with chemical inhibitors.

Hypoxia-inducible factor-1 (HIF-1): a potential target for intervention in ocular neovascular diseases

Constant oxygen supply is essential for proper tissue development, homeostasis and function of all eukaryotic organisms. Cellular response to reduced oxygen levels is mediated by the transcriptional regulator hypoxia-inducible factor-1 (HIF-1). It is a heterodimeric complex protein consisting of an oxygen dependent subunit (HIF-1α) and a constitutively expressed nuclear subunit (HIF-1β). In normoxic conditions, de novo synthesized cytoplasmic HIF-1α is degraded by 26S proteasome. Under hypoxic conditions, HIF-1α is stabilized, binds with HIF-1β and activates transcription of various target genes. These genes play a key role in regulating angiogenesis, cell survival, proliferation, chemotherapy, radiation resistance, invasion, metastasis, genetic instability, immortalization, immune evasion, metabolism and stem cell maintenance. This review highlights the importance of hypoxia signaling in development and progression of various vision threatening pathologies such as diabetic retinopathy, retinopathy of prematurity, age-related macular degeneration and glaucoma. Further, various inhibitors of HIF-1 pathway that may have a viable potential in the treatment of oxygen-dependent ocular diseases are also discussed.

Mechanisms of obesity-induced inflammation and insulin resistance: insights into the emerging role of nutritional strategies

Obesity and associated chronic inflammation initiate a state of insulin resistance (IR). The secretion of chemoattractants such as MCP-1 and MIF and of cytokines IL-6, TNF-α, and IL-1β, draw immune cells including dendritic cells, T cells, and macrophages into adipose tissue (AT). Dysfunctional AT lipid metabolism leads to increased circulating free fatty acids, initiating inflammatory signaling cascades in the population of infiltrating cells. A feedback loop of pro-inflammatory cytokines exacerbates this pathological state, driving further immune cell infiltration and cytokine secretion and disrupts the insulin signaling cascade. Disruption of normal AT function is causative of defects in hepatic and skeletal muscle glucose homeostasis, resulting in systemic IR and ultimately the development of type 2 diabetes. Pharmaceutical strategies that target the inflammatory milieu may have some potential; however there are a number of safety concerns surrounding such pharmaceutical approaches. Nutritional anti-inflammatory interventions could offer a more suitable long-term alternative; whilst they may be less potent than some pharmaceutical anti-inflammatory agents, this may be advantageous for long-term therapy. This review will investigate obese AT biology, initiation of the inflammatory, and insulin resistant environment; and the mechanisms through which dietary anti-inflammatory components/functional nutrients may be beneficial.

Resveratrol inhibits proliferation, angiogenesis and induces apoptosis in colon cancer cells: calorie restriction is the force to the cytotoxicity

The aim of this study was to examine the antitumour activity of resveratrol in human colorectal cancer cell lines (HCT116 and Caco2) and to explore its mechanism of action assuming that it is by calorie-restriction effect. Resveratrol inhibited the proliferation of colon cancer cells with half maximal inhibitory concentration (IC(50)) equal to 50 and 130 μM for HCT116 and Caco2, respectively. Caco2 cells appeared with significant time-dependent increase in the glycolytic pathway, a behaviour that was absent in HCT116 cells. Resveratrol (100 μM) significantly decreased the glycolytic enzymes (pyruvate kinase and lactate dehydrogenase) in Caco2 cells, while an increase in citrate synthase activity and a decrease in glucose consumption were observed in both cell lines. Moreover, resveratrol downregulated the expressions of leptin and c-Myc, and decreased the content of vascular endothelial growth factor. The apoptotic markers, caspases 3 and 8, were activated and the Bax/BCl2 ratio was increased. The study suggested a promising anticancer activity of resveratrol, calorie-restriction pathway may be one of the driving forces for this activity.

Resveratrol is a potent inhibitor of vascularization and cell proliferation in experimental endometriosis

STUDY QUESTION

Does the phytochemical compound resveratrol inhibit vascularization of endometriotic lesions?

SUMMARY ANSWER

Resveratrol suppresses the development of new microvessels in endometriotic lesions by inhibiting endothelial cell proliferation.

WHAT IS KNOWN ALREADY

Establishment and progression of endometriosis is crucially dependent on angiogenesis. Resveratrol is a pleiotropic agent, which dose-dependently suppresses the development of new blood vessels.

STUDY DESIGN, SIZE, DURATION

This was a randomized study in a mouse model of endometriosis. Twenty female BALB/c mice with surgically induced endometriosis were treated with resveratrol (40 mg/kg/day, n = 10) or vehicle (n = 10) for 4 weeks.

MATERIAL, SETTING, METHODS

Peritoneal and mesenteric endometriotic lesions were surgically induced by uterine tissue transplantation into the abdominal cavity of BALB/c mice. The animals were daily treated with resveratrol (40 mg/kg) or vehicle by oral gavage. Lesion growth, vascularization, apoptosis and cell proliferation were subsequently analyzed by means of high-resolution ultrasound imaging, caliper measurements, histology and immunohistochemistry throughout an observation period of 4 weeks.

MAIN RESULTS AND THE ROLE OF CHANCE

Resveratrol inhibited angiogenesis in peritoneal and mesenteric endometriotic lesions, as indicated by a significantly reduced microvessel density when compared with controls. Additional immunohistochemical analyses revealed that this was caused by a decreased proliferating activity of CD31-positive endothelial cells in the newly developing microvasculature of the lesions. In line with these findings, lesions in resveratrol-treated mice exhibited a reduced growth rate and a smaller final size than controls. This was associated with lower numbers of proliferating cell nuclear antigen- and Ki67-positive stromal and glandular cells. Apoptotic cells were not detectable in either group. To limit the role of chance, the experiments were conducted under standardized laboratory conditions with appropriate controls. Statistical significance was accepted for a value of P < 0.05.

LIMITATIONS, REASONS FOR CAUTION

Endometriotic lesions were surgically induced by uterine tissue transplantation without the use of pathological endometriotic tissue of human origin. Therefore, the results obtained in this mouse model may not fully correlate to human patients with endometriosis.

WIDER IMPLICATIONS OF THE FINDINGS

Resveratrol is a potent inhibitor of vascularization in endometriotic lesions. This, most probably, causes the suppression of lesion growth. Accordingly, resveratrol represents a promising candidate therapy for future phytochemical treatment of endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by a grant of the 'Freunde des Universitätsklinikums des Saarlandes'. The authors have no conflicts of interest to declare.

Resveratrol inhibits human nasopharyngeal carcinoma cell growth via blocking pAkt/p70S6K signaling pathways

Resveratrol (trans-3,4',5-trihydroxystilbene) has been shown to exert potent anticancer effects on various types of cancer through its anti-proliferative, anti-angiogenic, antioxidant and pro-apoptotic functions. There is still a lack of experimental evidence regarding whether resveratrol has potential anticancer activity in human nasopharyngeal carcinoma (NPC) cells. The purpose of this study was to explore the anticancer activity of resveratrol in human NPC cells both in vitro and in vivo. Our results indicated that treatment with resveratrol led to a time- and dose-dependent decrease in cell proliferation in NPC cells. A dose-dependent increase in apoptosis in response to resveratrol treatment was also observed in NPC cells. Flow cytometric analysis showed that treatment of NPC cells with resveratrol led to cell cycle arrest at the S and G2/M phases. Mechanistically, resveratrol treatment downregulated the expression of Bcl-2 and hypoxia-inducible factor-1α (HIF-1α) proteins and upregulated the expression of caspase-3 protein. In addition, resveratrol treatment also significantly decreased the phosphorylation levels of Akt1, p70S6K and p-4E-BP-1 and the protein expression of several cyclins involved in cell cycle regulation. In vivo studies further showed that resveratrol was able to significantly inhibit the growth of NPC tumor xenografts in nude mice. Collectively, our findings suggest that resveratrol exerts potent anti-prolife-rative and pro-apoptotic effects on human NPC cells possibly through interfering with the pAkt1/p70S6K signaling pathways, thus it may potentially be developed as an effective agent for chemoprevention and chemotherapy of human NPC.

A cross-species analysis method to analyze animal models' similarity to human's disease state

Background

Animal models are indispensable tools in studying the cause of human diseases and searching for the treatments. The scientific value of an animal model depends on the accurate mimicry of human diseases. The primary goal of the current study was to develop a cross-species method by using the animal models' expression data to evaluate the similarity to human diseases' and assess drug molecules' efficiency in drug research. Therefore, we hoped to reveal that it is feasible and useful to compare gene expression profiles across species in the studies of pathology, toxicology, drug repositioning, and drug action mechanism.

Results

We developed a cross-species analysis method to analyze animal models' similarity to human diseases and effectiveness in drug research by utilizing the existing animal gene expression data in the public database, and mined some meaningful information to help drug research, such as potential drug candidates, possible drug repositioning, side effects and analysis in pharmacology. New animal models could be evaluated by our method before they are used in drug discovery.

We applied the method to several cases of known animal model expression profiles and obtained some useful information to help drug research. We found that trichostatin A and some other HDACs could have very similar response across cell lines and species at gene expression level. Mouse hypoxia model could accurately mimic the human hypoxia, while mouse diabetes drug model might have some limitation. The transgenic mouse of Alzheimer was a useful model and we deeply analyzed the biological mechanisms of some drugs in this case. In addition, all the cases could provide some ideas for drug discovery and drug repositioning.

Conclusions

We developed a new cross-species gene expression module comparison method to use animal models' expression data to analyse the effectiveness of animal models in drug research. Moreover, through data integration, our method could be applied for drug research, such as potential drug candidates, possible drug repositioning, side effects and information about pharmacology.

Resveratrol inhibits TGF-β1-induced epithelial-to-mesenchymal transition and suppresses lung cancer invasion and metastasis

Epithelial-to-mesenchymal transition (EMT) is a cellular process during which epithelial polarized cells become motile mesenchymal-appearing cells, which in turn promotes carcinoma invasion and metastasis. Resveratrol (trans-3,4',5-trihydroxystilbene) is a natural polyphenolic compound found in grapes, red wine and several other plants. Numerous reports in the literature indicate that resveratrol can suppress cancer invasion and metastasis. However, the underlying mechanisms of inhibiting metastasis by resveratrol are complex, not fully elucidated and the subject of intense scientific debate. Despite evidence indicating that EMT can be a target for resveratrol, little is known about the effect of resveratrol on lung cancer cells. Our previous studies demonstrated that TGF-β1 induces EMT to promote lung adenocarcinoma invasion and metastasis. To understand the repressive role of resveratrol in lung cancer invasion and metastasis, we sought to investigate the potential use of resveratrol as an inhibitor of TGF-β1-induced EMT development in A549 lung cancer cells in vitro. Here we show that when A549 cells are treated with TGF-β1 and resveratrol, the latter inhibits the initiation of TGF-β1-induced EMT. Our results show that 20 μM resveratrol increases expression of the epithelial phenotype marker E-cadherin and represses the expression of the mesenchymal phenotype markers, Fibronectin and Vimentin during the initiation of TGF-β1-induced EMT. Resveratrol also inhibits expression of EMT-inducing transcription factors Snail1 and Slug, although the expression of the Twist1 transcription factor remained unchanged. Resveratrol inhibits the TGF-β1-induced increase in cell adhesion, migration and invasion of A549 lung cancer cells. Taken together, our findings provide new evidence that resveratrol suppresses lung cancer invasion and metastasis in vitro through inhibiting TGF-β1-induced EMT.

Regulation of CXCR4 gene expression in breast cancer cells under diverse stress conditions

Chronic inflammation is a critical component in breast cancer progression. Pro-inflammatory mediators along with growth/survival factors within the tumor microenvironment potentiate the expression of pro-inflammatory cytokines (IL-1, IL-6, TNF-α), chemotactic cytokines and their receptors (CXCR4, CXCL12, CXCL8) and angiogenic factors (VEGF) that often overcome the effect of anti-inflammatory molecules (IL-4, IL-10) thus evading the host's antitumor immunity. Detailed knowledge, therefore, of the regulatory mechanisms determining cytokine levels is essential to understand the pathogenesis of breast cancer. HIF-1α and NF-κB transcription factors are important players for the establishment of a pro-inflammatory and potentially oncogenic environment. HIF-1α is the key mediator of the cellular response to oxygen deprivation and induces the expression of genes involved in survival and angiogenesis within solid hypoxic tumors. The expression of these genes is often modulated by the p53 tumor suppressor protein that induces apoptosis or cell cycle arrest in neoplastic cells. Functional crosstalk between HIF-1α and p53 pathways mediated by modulators shared between the two transcription factors such as SRC-1 and SIRT-1 differentially regulate the expression of distinct subsets of their target genes under variable stress conditions. In an attempt to shed light on the complex regulatory mechanisms involved in cancer-related inflammation, we investigated the role of the two common p53 and HIF-1α co-regulators SRC-1 and SIRT-1, in the expression of the highly potent metastatic chemokine receptor CXCR4. Both SRC-1 and SIRT-1 overexpression in DSFX-treated MCF-7 cells reduced CXCR4 cellular levels implying that both co-regulators are crucial factors in the determination of the metastatic potential of breast cancer cells.

Resveratrol ameliorates high-glucose-induced hyperpermeability mediated by caveolae via VEGF/KDR pathway

Endothelial hyperpermeability induced by hyperglycemia is the initial step in the development of atherosclerosis, one of the most serious cardiovascular complications in diabetes. In the present study, we investigated the effects of resveratrol (RSV), a bioactive ingredient extracted from Chinese herb rhizoma polygonum cuspidatum, on permeability in vitro and the molecular mechanisms involved. Permeability was assessed by the efflux of fluorescein isothiocyanate (FITC)-dextran permeated through the monolayer endothelial cells (ECs). The mRNA levels, protein expressions, and secretions were measured by quantitative real-time PCR, western blot, and ELISA, respectively. Increased permeability and caveolin-1 (cav-1) expression were observed in monolayer ECs exposed to high glucose. Resveratrol treatment alleviated the hyperpermeability and the overexpression of cav-1 induced by high glucose in a dose-dependent manner. β-Cyclodextrin, a structural inhibitor of caveolae, reduced the hyperpermeability caused by high glucose. Resveratrol also down-regulated the increased expressions of vascular endothelial growth factor (VEGF) and kinase insert domain receptor (KDR, or VEGF receptor-2) induced by high glucose. Inhibition of VEGF/KDR pathway by using SU5416, a selective inhibitor of KDR, alleviated the hyperpermeability and the cav-1 overexpression induced by high glucose. The above results demonstrate that RSV ameliorates caveolae-mediated hyperpermeability induced by high glucose via VEGF/KDR pathway.

Phytochemicals and their impact on adipose tissue inflammation and diabetes

Type 2 diabetes mellitus is an inflammatory disease and the mechanisms that underlie this disease, although still incompletely understood, take place in the adipose tissue of obese subjects. Concurrently, the prevalence of obesity caused by Western diet's excessive energy intake and the lack of exercise escalates, and is believed to be causative for the chronic inflammatory state in adipose tissue. Overnutrition itself as an overload of energy may induce the adipocytes to secrete chemokines activating and attracting immune cells to adipose tissue. But also inflammation-mediating food ingredients like saturated fatty acids are believed to directly initiate the inflammatory cascade. In addition, hypoxia in adipose tissue as a direct consequence of obesity, and its effect on gene expression in adipocytes and surrounding cells in fat tissue of obese subjects appears to play a central role in this inflammatory response too. In contrast, revisiting diet all over the world, there are also some natural food products and beverages which are associated with curative effects on human health. Several natural compounds known as spices such as curcumin, capsaicin, and gingerol, or secondary plant metabolites catechin, resveratrol, genistein, and quercetin have been reported to provide an improved health status to their consumers, especially with regard to diabetes, and therefore have been investigated for their anti-inflammatory effect. In this review, we will give an overview about these phytochemicals and their role to interfere with inflammatory cascades in adipose tissue and their potential for fighting against inflammatory diseases like diabetes as investigated in vivo.

Protective role of resveratrol against cisplatin induced ototoxicity in guinea pigs

OBJECTIVE

The aim of this study was to evaluate the effectiveness of systemic administration of resveratrol against cisplatin-induced ototoxicity in guinea pigs.

MATERIALS AND METHODS

Healthy guinea pigs (n=24) were randomly divided into four groups. Group 1 (n=6) received resveratrol+cisplatin, group 2 (n=6) received 4% ethanol+cisplatin, group 3 (n=6) received cisplatin, and group 4 (n=6) received saline. Cisplatin was administered at a dose of 10mg/kg/day on days 14 and 15 of the study. Resveratrol (10mg/kg/day), 4% ethanol, and saline were administered throughout the study. Baseline auditory brainstem responses (ABR) (4 kHz, 8 kHz, and click stimulus) were determined for all groups. ABR was repeated 72 h after the last dose of cisplatin in order to record the threshold shifts. The ABR threshold shifts for the click stimulus, 4-kHz- and 8-kHz-frequency stimuli were compared after drug administration. After follow-up ABRs the animals sacrificed under deep sedation and their cochleae were removed. Left cochleae were immediately harvested for measurement of level of reactive oxygen species (ROS). Right cochleae were prepared for histological changes which were observed by scanning electron microscopy (SEM).

RESULTS

For the all stimulus, there was a significant threshold difference among the groups (p<0.01). Group 3 had a significantly higher threshold shift at all stimuli when compared with groups 1 and 4. There was no significant threshold shifts in all stimuli between groups 2 and 3. The resveratrol-treated group 1 showed preservation of threshold in ABR (p ≤ 0.05). SEM showed that inner and outer hair cells were preserved in the group 1. Level of reactive oxygen species (ROS) were significantly higher in groups 2 and 3 compared with groups 1 and 4 (p ≤ 0.05).

CONCLUSION

These results indicated that systemic administration of resveratrol afforded statistically significant protection to the cochlea of guinea pigs from cisplatin toxicity. Experimental dose of resveratrol injections may have a protective effect against cisplatin ototoxicity in guinea pigs.

Recent advances in hypoxia-inducible factor (HIF)-1 inhibitors

Tumor hypoxia has been recognized as a common feature of solid tumors and a negative prognostic factor for response to treatment and survival of cancer patients. The discovery of hypoxia-inducible factor-1 (HIF-1), a molecular determinant of responses to hypoxia in mammalian cells, has renewed enthusiasm for discovery and development of targeted therapies exploiting the hypoxic tumor microenvironment. HIF-1 activity in tumors depends on availability of the HIF-1α subunit, the levels of which increase under hypoxic conditions and through activation of oncogenes and/or inactivation of tumor suppressor genes. Increased HIF-1 has been correlated with increased angiogenesis, aggressive tumor growth, and poor patient prognosis, leading to current interest in HIF-1 as promising anticancer drug target. In spite of an ever increasing number of putative small molecule inhibitors of HIF-1, only a few are progressing through preclinical and early clinical development. In this review, we will discuss recent advances in discovery and development of small molecule inhibitors that target the HIF-1 pathway as potential anticancer agents.

Rhapontigenin inhibited hypoxia inducible factor 1 alpha accumulation and angiogenesis in hypoxic PC-3 prostate cancer cells

Hypoxia inducible factor 1 alpha (HIF-1α) is frequently over-expressed in the numerous types of cancer and plays an important role in angiogenesis. In the present study, the inhibitory mechanism of rhapontigenin isolated from Vitis coignetiae was investigated on HIF-1α stability and angiogenesis in human prostate cancer PC-3 cells. Rhapontigenin significantly suppressed HIF-1α accumulation at protein level but not at mRNA level in PC-3 cells under hypoxia. Also, rhapontigenin suppressed hypoxia-induced HIF-1α activation in various cancer cells, such as colorectal adenocarcinoma (SW620), breast adenocarcinoma (MCF-7), fibrosarcoma (HT-1080) and prostate carcinoma (LNCaP). Interestingly, rhapontigenin had more potency in inhibition of hypoxia-induced HIF-1α expression than that of resveratrol, a known HIF-1α inhibitor. In addition, rhapontigenin promoted hypoxia-induced HIF-1α degradation and cycloheximide (CHX) blocked protein synthesis. A prolyl hydroxylase (PHD) inhibitor dimethyloxalylglycine (DMOG) is usually utilized to examine whether prolyl hydroxylation is involved in inhibition of HIF-1α accumulation. Here, DMOG recovered HIF-1α accumulation inhibited by rhapontigenin. Immunoprecipitation assay also revealed that rhapotigenin enhanced the binding of hydroxylated HIF-1α to von Hippel-Lindau (VHL) tumor suppressor protein. Furthermore, rhapontigenin reduced vascular endothelial growth factor (VEGF) secretion in hypoxic PC-3 cells as well as suppressed tube formation in human umbilical vein endothelial cells (HUVECs) treated by the conditioned media of hypoxic PC-3 cells. However, anti-angiogenic effect of rhapontigenin in hypoxic PC-3 cells was reversed by DMOG. Taken together, these findings suggest that rhapontigenin inhibits HIF-1α accumulation and angiogenesis in PC-3 prostate cancer cells.

Cancer and diet: How are they related?

Extensive research in the past decade has revealed cancer to be a multigenic disease caused by perturbation of multiple cell signalling pathways and dysregulation of numerous gene products, all of which have been linked to inflammation. It is also becoming evident that various lifestyle factors, such as tobacco and alcohol use, diet, environmental pollution, radiation and infections, can cause chronic inflammation and lead to tumourigenesis. Chronic diseases caused by ongoing inflammation therefore require chronic, not acute, treatment. Nutraceuticals, compounds derived from fruits, vegetables, spices and cereals, can be used chronically. This study discusses the molecular targets of some nutraceuticals that happen to be markers of chronic inflammation and how they can prevent or treat cancer. These naturally-occurring agents in the diet have great potential as anti-cancer drugs, thus proving Hippocrates, who proclaimed 25 centuries ago, 'Let food be thy medicine and medicine be thy food'.

Resveratrol prevents inflammation-dependent hepatic melanoma metastasis by inhibiting the secretion and effects of interleukin-18

BACKGROUND

Implantation and growth of metastatic cancer cells at distant organs is promoted by inflammation-dependent mechanisms. A hepatic melanoma metastasis model where a majority of metastases are generated via interleukin-18-dependent mechanisms was used to test whether anti-inflammatory properties of resveratrol can interfere with mechanisms of metastasis.

METHODS

Two experimental treatment schedules were used: 1) Mice received one daily oral dose of 1 mg/kg resveratrol after cancer cell injection and the metastasis number and volume were determined on day 12. 2) Mice received one daily oral dose of 1 mg/kg resveratrol along the 5 days prior to the injection of cancer cells and both interleukin-18 (IL-18) concentration in the hepatic blood and microvascular retention of luciferase-transfected B16M cells were determined on the 18th hour. In vitro, primary cultured hepatic sinusoidal endothelial cells were treated with B16M-conditioned medium to mimic their in vivo activation by tumor-derived factors and the effect of resveratrol on IL-18 secretion, on vascular cell adhesion molecule-1 (VCAM-1) expression and on tumor cell adhesion were studied. The effect of resveratrol on melanoma cell activation by IL-18 was also studied.

RESULTS

Resveratrol remarkably inhibited hepatic retention and metastatic growth of melanoma cells by 50% and 75%, respectively. The mechanism involved IL-18 blockade at three levels: First, resveratrol prevented IL-18 augmentation in the blood of melanoma cell-infiltrated livers. Second, resveratrol inhibited IL-18-dependent expression of VCAM-1 by tumor-activated hepatic sinusoidal endothelium, preventing melanoma cell adhesion to the microvasculature. Third, resveratrol inhibited adhesion- and proliferation-stimulating effects of IL-18 on metastatic melanoma cells through hydrogen peroxide-dependent nuclear factor-kappaB translocation blockade on these cells.

CONCLUSIONS

These results demonstrate multiple sites for therapeutic intervention using resveratrol within the prometastatic microenvironment generated by tumor-induced hepatic IL-18, and suggest a remarkable effect of resveratrol in the prevention of inflammation-dependent melanoma metastasis in the liver.