Resveratrol and its synthetic derivatives exert opposite effects on mesothelial cell-dependent angiogenesis via modulating secretion of VEGF and IL-8/CXCL8

Dual Effects of Resveratrol on the Expression and Secretion of Angiogenic Factors

Angiogenesis is an essential process in the growth, development, and transition of tumors from dormancy to proliferating state. Resveratrol (RSV), as a natural polyphenolic compound, is claimed to be effective in regulating angiogenesis. This study aimed to evaluate the impact of RSV onthe angiogenesis process in HUVECs (human umbilical vein endothelial cells) alone and co-cultured with Jurkat cells. The effects of RSV on HUVECs and Jurkat cell viability and apoptosis were measured by MTT and Annexin-V/PI methods. HUVECs were co-cultured with pre-treated Jurkat cells and incubated for 24 h, 48 h and 72 h. The angiogenesis process in HUVECs and Jurkat cells alone and in co-culture models was investigated by analyzing the expression of VEGF, VEGFR-2, and Interleukin-8 (IL-8) employing qPCR and ELISA. RSV at low concentration (40 µM) had no significant effects on apoptosis rate of HUVECs, but higher concentrations (80-160 µM) increased apoptosis in co-culture method and HUVECs alone. RSV significantly reduced VEGFR2 and IL-8 gene expression also, IL-8 protein concentration in HUVECs, but the effects of this drug in the HUVECs-Jurkats co-culture were different. Expression of VEGF in Jurkat cells increased following treatment with RSV. RSV had direct anti-angiogenic effects on HUVECs. Unexpectedly its indirect effects were not significant on HUVECs-Jurkats co-culture. Results of our study showed, RSV may be effective in anti-angiogenesis therapy, but in some situations, it may induce angiogenesis. So, appropriate concentrations should achieve to minimize the unpredicted effects of RSV.

Vascular endothelial growth factor-mediated peritoneal neoangiogenesis in peritoneal dialysis

Peritoneal dialysis (PD) is an important renal replacement therapy for patients with end-stage renal diseases, which is limited by peritoneal neoangiogenesis leading to ultrafiltration failure (UFF). Vascular endothelial growth factor (VEGF) and its receptors are key angiogenic factors involved in almost every step of peritoneal neoangiogenesis. Impaired mesothelial cells are the major sources of VEGF in the peritoneum. The expression of VEGF will be up-regulated in specific pathological conditions in PD patients, such as with non-biocompatible peritoneal dialysate, uremia and inflammation, and so on. Other working cells (i.e. vascular endothelial cells, macrophages and adipocytes) can also stimulate the secretion of VEGF. Meanwhile, hypoxia and activation of complement system further aggravate peritoneal injury and contribute to neoangiogenesis. There are several signalling pathways participating in VEGF-mediated peritoneal neoangiogenesis including tumour growth factor-β, Wnt/β-catenin, Notch and interleukin-6/signal transducer and activator of transcription 3. Moreover, VEGF is highly expressed in dialysate effluent of long-term PD patients and is associated with peritoneal transport function, which supports its role in the alteration of peritoneal structure and function. In this review, we systematically summarize the angiogenic effect of VEGF and evaluate it as a potential target for the prevention of peritoneal neoangiogenesis and UFF. Preservation of the peritoneal membrane using targeted therapy of VEGF-mediated peritoneal neoangiogenesis may increase the longevity of the PD modality for those who require life-long dialysis.

Resveratrol as a Tumor-Suppressive Nutraceutical Modulating Tumor Microenvironment and Malignant Behaviors of Cancer

Tumor-suppressive effects of resveratrol have been shown in various types of cancer. However, regulation of tumor microenvironment by resveratrol is still unclear. Recent findings suggest resveratrol can potentiate its tumor-suppressive effect through modulation of the signaling pathways of cellular components (fibroblasts, macrophages and T cells). Also, studies have shown that resveratrol can suppress malignant phenotypes of cancer cells acquired in response to stresses of the tumor microenvironment, such as hypoxia, oxidative stress and inflammation. We discuss the effects of resveratrol on cancer cells in stress environment of tumors as well as interactions between cancer cells and non-cancer cells in this review.

Serum from patients with chronic obstructive pulmonary disease induces senescence-related phenotype in bronchial epithelial cells

Chronic obstructive pulmonary disease (COPD) is a risk factor for the development of lung cancer (LC). The mechanism of interplay between both diseases remains poorly recognized. This report examines whether COPD may cause a senescence response in human bronchial epithelial cells (HBECs), leading to the progression of LC in a senescence-dependent manner. The results show that HBECs exposed to serum from COPD patients manifest increased expression of markers of cellular senescence, including senescence-associated β-galactosidase (SA-β-Gal), histone γ-H2A.X, and p21, as compared to the serum of healthy donors. This effect coincides with an increased generation of reactive oxygen species by these cells. The clinical analysis demonstrated that COPD may cause the senescence, independently on smoking status and disease severity. The concentrations of CXCL5, CXCL8/IL-8 and VEGF were higher in conditioned medium (CM) harvested from HBECs after exposure to COPD serum as compared to controls. In addition, CM treated with serum from COPD patients stimulated adhesion of A549 cancer cells to HBECs, as well as accelerating cancer cell proliferation and migration in vitro. Collectively, these findings indicate that COPD may induce senescence-like changes in HBECs and thus enhance some processes associated with the progression of lung cancer.

Procancerogenic activity of senescent cells: A case of the peritoneal mesothelium

Human peritoneal mesothelial cells belong to a narrow group of somatic cells in which both the triggers and the mechanisms of senescence have already been well defined. Importantly, senescent mesothelial cells have been found in the peritoneal cavity in vivo. From a clinical point of view, peritoneal mesothelial cells have been recognized as playing a critical role in the intraperitoneal development of tumor metastases. The pro-cancerogenic behavior of mesothelial cells is even more pronounced when the cells exhaust their proliferative capacity and become senescent. In this review, we summarize the current state of art regarding the contribution of peritoneal mesothelial cells in the progression of ovarian, colorectal, and pancreatic carcinomas, with particular attention paid to the cancer-promoting activity of their senescent counterparts. Moreover, we delineate the mechanisms, mediators, and signaling pathways that are engaged by the senescent mesothelial cells to support such vital elements of cancer progression as adhesion, proliferation, migration, invasion, epithelial-mesenchymal transition, and angiogenesis. Finally, we discuss the experimental evidence regarding both natural and synthetic compounds that may either prevent or restrict cancer development by delaying senescence of mesothelial cells.

Therapeutic Effects of Resveratrol in a Mouse Model of LPS and Cigarette Smoke-Induced COPD

This study was designed to examine whether resveratrol exerts the protective effects on LPS and cigarette smoke (LC)-induced COPD in a murine model. In lung histopathological studies, H&E, Masson's trichrome, and AB-PAS staining were performed. The cytokines (IL-6, IL-17, TGF-β, and TNF-α) and inflammatory cells in BALF were determined. The Beclin1 level in the lungs of mouse was analyzed. Compared with the LC-induced mouse, the level of inflammatory cytokines (IL-17, IL-6, TNF-α, and TGF-β) of the BALF in the resveratrol + cigarette smoke-treated mouse had obviously decreased. Histological examination of the lung tissue revealed that the resveratrol treatment attenuated the fibrotic response and mucus hypersecretion. In addition, resveratrol inhibited the expression of the Beclin1 protein in mouse lungs. The presented findings collectively suggest that resveratrol has a therapeutic effect on mouse LC-induced COPD, and its mechanism of action might be related to reducing the production of the Beclin1 protein.

Senescent peritoneal mesothelium creates a niche for ovarian cancer metastases

Although both incidence and aggressiveness of ovarian malignancy rise with age, the exact reason for this tendency, in particular the contribution of senescent cells, remains elusive. In this project we found that the patient's age determines the frequency of intraperitoneal metastases of ovarian cancer. Moreover, we documented that senescent human peritoneal mesothelial cells (HPMCs) stimulate proliferation, migration and invasion of ovarian cancer cells in vitro, and that this effect is related to both the activity of soluble agents released to the environment by these cells and direct cell-cell contact. The panel of mediators of the pro-cancerous activity of senescent HPMCs appeared to be cancer cell line-specific. The growth of tumors in a mouse peritoneal cavity was intensified when the cancer cells were co-injected together with senescent HPMCs. This effect was reversible when the senescence of HPMCs was slowed down by the neutralization of p38 MAPK. The analysis of lesions excised from the peritoneum of patients with ovarian cancer showed the abundance of senescent HPMCs in close proximity to the cancerous tissue. Collectively, our findings indicate that senescent HPMCs which accumulate in the peritoneum in vivo may create a metastatic niche facilitating intraperitoneal expansion of ovarian malignancy.

Colorectal cancer-promoting activity of the senescent peritoneal mesothelium

Gastrointestinal cancers metastasize into the peritoneal cavity in a process controlled by peritoneal mesothelial cells (HPMCs). In this paper we examined if senescent HPMCs can intensify the progression of colorectal (SW480) and pancreatic (PSN-1) cancers in vitro and in vivo. Experiments showed that senescent HPMCs stimulate proliferation, migration and invasion of SW480 cells, and migration of PSN-1 cells. When SW480 cells were injected i.p. with senescent HPMCs, the dynamics of tumor formation and vascularization were increased. When xenografts were generated using PSN-1 cells, senescent HPMCs failed to favor their growth. SW480 cells subjected to senescent HPMCs displayed up-regulated expression of transcripts for various pro-cancerogenic agents as well as increased secretion of their products. Moreover, they underwent an epithelial-mesenchymal transition in the Smad 2/3-Snail1-related pathway. The search for mediators of senescent HPMC activity showed that increased SW480 cell proliferation was stimulated by IL-6, migration by CXCL8 and CCL2, invasion by IL-6, MMP-3 and uPA, and epithelial-mesenchymal transition by TGF-β1. Secretion of these agents by senescent HPMCs was increased in an NF-κB- and p38 MAPK-dependent mechanism. Collectively, our findings indicate that in the peritoneum senescent HPMCs may create a metastatic niche in which critical aspects of cancer progression become intensified.

Ovarian cancer-derived ascitic fluids induce a senescence-dependent pro-cancerogenic phenotype in normal peritoneal mesothelial cells

PURPOSE

After the seeding ovarian cancer cells into the peritoneal cavity, ascitic fluid creates a microenvironment in which these cells can survive and disseminate. The exact nature of the interactions between malignant ascitic fluids and peritoneal mesothelial cells (HPMCs) in ovarian cancer progression has so far remained elusive. Here we assessed whether malignant ascitic fluids may promote the senescence of HPMCs and, by doing so, enhance the acquisition of their pro-cancerogenic phenotype.

METHODS

Primary omentum-derived HPMCs, ovarian cancer-derived cell lines (A2780, OVCAR-3, SKOV-3), malignant ascitic fluids and benign ascitic fluids from non-cancerous patients were used in this study. Ovarian cancer cell proliferation, as well as HPMC proliferation and senescence, were determined using flow cytometry and β-galactosidase assays, respectively. Ovarian cancer cell migration was quantified using a Transwell assay. The concentrations of soluble agents in ascitic fluids, conditioned media and cell lysates were measured using DuoSet® Immunoassay Development kits.

RESULTS

We found that HPMCs, when exposed to malignant ascitic fluids, exhibited decreased proliferation and increased senescence rates. The malignant ascitic fluids were found to contain elevated levels of HGF, TGF-β1 and GRO-1, of which HGF and GRO-1 were able to induce senescence in HPMCs. We also found that HPMCs subjected to malignant ascitic fluids or exogenously added HGF and GRO-1 stimulated ovarian cancer cell progression, which was manifested by an increased production of HA (adhesion), uPA (proliferation), IL-8 and MCP-1 (migration).

CONCLUSION

Our results indicate that malignant ascitic fluids may contribute to ovarian cancer progression by accelerating the senescence of HPMCs.

Enhancement of anticancer potential of polyphenols by covalent modifications

As evidenced by a growing number of respective clinical trials, a promising and increasingly valued approach to cancer prevention is chemoprevention which is based on using synthetic, semisynthetic, or natural compounds with the aim of preventing, delaying, arresting, or reversing carcinogenesis. Research carried out in the last two decades indicates that natural polyphenols isolated from plants (as well as their derivatives and synthetic analogs) exhibit pleiotropic actions toward cancer cells and therefore they could be used in both cancer prevention and therapy. This review discusses selected covalent modifications of polyphenols as a means for increasing their anticancer potential in relation to the parent compounds. The modifications include hydroxylation, methylation, acylation, and galloylation, among others. They were demonstrated to enhance cytotoxic, pro-oxidant, antiproliferative, proapoptotic, proautophagic, and antimigratory activities of phenolics toward various cancer cell lines in vitro. Importantly, some derivatives proved to suppress tumor growth and metastasis in animal models more strongly than the parent compounds. Some of the above-mentioned covalent modifications were also shown to increase absorption and tissue distribution of tested phenolic compounds in vivo. Anticancer clinical trials with polyphenol derivatives therefore seem warranted.

Resveratrol-loaded Nanoparticles Induce Antioxidant Activity against Oxidative Stress

Resveratrol acts as a free radical scavenger and a potent antioxidant in the inhibition of numerous reactive oxygen species (ROS). The function of resveratrol and resveratrol-loaded nanoparticles in protecting human lung cancer cells (A549) against hydrogen peroxide was investigated in this study. The 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay was performed to evaluate the antioxidant properties. Resveratrol had substantially high antioxidant capacity (trolox equivalent antioxidant capacity value) compared to trolox and vitamin E since the concentration of resveratrol was more than 50 μM. Nanoparticles prepared from β-lactoglobulin (β-lg) were successfully developed. The β-lg nanoparticle showed 60 to 146 nm diameter in size with negatively charged surface. Non-cytotoxicity was observed in Caco-2 cells treated with β-lg nanoparticles. Fluorescein isothiocynate-conjugated β-lg nanoparticles were identified into the cell membrane of Caco-2 cells, indicating that nanoparticles can be used as a delivery system. Hydrogen peroxide caused accumulation of ROS in a dose- and time-dependent manner. Resveratrol-loaded nanoparticles restored H₂O₂-induced ROS levels by induction of cellular uptake of resveratrol in A549 cells. Furthermore, resveratrol activated nuclear factor erythroid 2-related factor 2-Kelch ECH associating protein 1 (Nrf2-Keap1) signaling in A549 cells, thereby accumulation of Nrf2 abundance, as demonstrated by western blotting approach. Overall, these results may have implications for improvement of oxidative stress in treatment with nanoparticles as a biodegradable and non-toxic delivery carrier of bioactive compounds.

Supplementation with high-dose trans-resveratrol improves ultrafiltration in peritoneal dialysis patients: a prospective, randomized, double-blind study

BACKGROUND

Ultrafiltration (UF) failure mostly contributes to technical failure in peritoneal dialysis (PD) patients, and one of its responsible factors is peritoneal angiogenesis. Resveratrol has been proposed to have an angiogenesis-ameliorating effect on tumor patients. We hypothesize trans-resveratrol has beneficial effects on angiogenesis-related markers in PD patients.

METHODS

In this prospective, randomized, and double-blind trial, 72 patients were randomly assigned to 12-week treatment of low-dose or high-dose (150 or 450 mg/d) trans-resveratrol or a placebo. Visits were scheduled at 0, 4, 8, and 12 weeks after treatment. Clinical indices including 24-hour UF volume, UF rate, 24-hour urine volume, residual renal function, and dialysis adequacy (kt/v) were measured. Angiogenesis markers including vascular endothelial growth factor (VEGF), fetal liver kinase-1 (Flk-1), angiopoietin-2 (Ang-2), tyrosine kinase 2 (Tie-2), and thrombospondin-1 (Tsp-1) in peritoneal effluent were also assessed by enzyme-linked immunosorbent assay.

RESULTS

Finally, 64 out of 72 patients were analyzed, 18 in the high-dose group, 22 in the low-dose group, and 24 in the placebo group. Over the 12-week period, patients in the high-dose group [mean change from baseline (95% CI): 171.4 (141.3-201.5) (mL), p = 0.003 (Net UF); 11.3(10.5-12.1) (mL/h), p = 0.02 (UF rate)] or the low-dose group [mean change from baseline (95% CI: 98.1 (49.5-146.7) (mL), p = 0.007 (Net UF); 6.5 (4.4-8.6) (mL/h), p = 0.04 (UF rate)] versus the placebo group had a significantly greater improvement in mean net UF volume and UF rate. The appearance rates of VEGF, Flk-1, and Ang-2 were more significantly reduced (appearance rates of Tie-2 and Tsp-1 increased) in the high-dose group versus the placebo group, but not in the low-dose group.

CONCLUSION

Supplementation with trans-resveratrol is beneficial to improve ultrafiltration in PD patients, and high-dose supplementation may improve ultrafiltration by ameliorating angiogenesis induced by conventional lactate-buffered PD solutions.

Senescent peritoneal mesothelium induces a pro-angiogenic phenotype in ovarian cancer cells in vitro and in a mouse xenograft model in vivo

It is believed that senescent cells contribute to the progression of primary and metastatic tumors, however, the exact mechanisms of this activity remain elusive. In this report we show that senescent human peritoneal mesothelial cells (HPMCs) alter the secretory profile of ovarian cancer cells (A2780, OVCAR-3, SKOV-3) by increasing the release of four angiogenic agents: CXCL1, CXCL8, HGF, and VEGF. Proliferation and migration of endothelial cells subjected to conditioned medium generated by: cancer cells modified by senescent HPMCs; cancer cells co-cultured with senescent HPMCs; and by early-passage HPMCs from aged donors, were markedly intensified. The same was the case for the vascularization, size and number of tumors that developed in the mouse peritoneum upon injection of ovarian cancer cells with senescent HPMCs. When the identified pro-angiogenic proteins were neutralized in conditioned medium from the cancer cells, both aspects of endothelial cell behavior intensified in vitro in response to senescent HPMCs were markedly reduced. The search for mediators of senescent HPMC activity using specific neutralizing antibodies and recombinant exogenous proteins showed that the intensified angiogenic potential of cancer cells was elicited by IL-6 and TGF-β1. At the transcriptional level, increased proliferation and migration of endothelial cells exposed to cancer cells modified by senescent HPMCs was regulated by HIF-1α, NF-κB/p50 and AP-1/c-Jun. Collectively, our findings indicate that senescent HPMCs may promote the progression of ovarian cancer cells by reprogramming their secretory phenotype towards increased production of pro-angiogenic agents and subsequent increase in the angiogenic capabilities of the vascular endothelium.

Therapeutic effects of resveratrol in a mouse model of HDM-induced allergic asthma

Asthma is an inflammatory disease of the lungs characterized by airway remolding. In this study, we examined whether resveratrol exerts protective effects on allergic asthma in a murine model. To investigate the effects of resveratrol on allergic airway inflammation in house dust mite (HDM)-induced mouse asthma and explore its mechanism, a chronic asthma mouse model was established by intranasally administering extracts of HDM (25μg of protein in 10μl of saline) for 5days/week for up to 7 consecutive weeks. Resveratrol (50mg/kg body weight), dexamethasone (1mg/kg body weight) or a vehicle was administered orally 1h before antigen challenges for up to 2weeks. Compared with the HDM-induced mice, the level of TNF-α of the BALF in the resveratrol+HDM-treated mice had obviously decreased. Histological examination of the lung tissue revealed that the resveratrol treatments attenuated the fibrotic response and airway inflammation. In addition, resveratrol inhibited the expression of the Syk protein and degranulation in mast cells. The presented findings collectively suggest that resveratrol has a therapeutic effect on mouse allergic asthma, and its mechanism of action might be related to reducing the production of the Syk protein.

Synthetic resveratrol analogue, 3,3',4,4',5,5'-hexahydroxy-trans-stilbene, accelerates senescence in peritoneal mesothelium and promotes senescence-dependent growth of gastrointestinal cancers

3,3′,4,4′,5,5′-Hexahydroxy-trans-stilbene (M8) is a synthetic resveratrol derivative, advertised as a candidate drug highly effective against numerous malignancies. Because multiple tumors prone to M8 frequently metastasize into the peritoneal cavity, this study was aimed at establishing the effect of M8 on the growth and senescence of human peritoneal mesothelial cells (HPMCs), the largest cell population within the peritoneum, actively involved in the intraperitoneal spread of cancer. The study showed that M8, used at the highest non-toxic dose of 10 μM, impairs proliferation and accelerates senescence in cultured HPMCs via an oxidative stress-dependent mechanism. At the same time, soluble factors released to the environment by HPMCs that senesced prematurely in response to M8 promoted growth of colorectal and pancreatic carcinomas in vitro. These findings indicate that M8 may indirectly—through the modification of normal (mesothelial) cells phenotype—facilitate an expansion of cancer cells, which challenges the postulated value of this stilbene in chemotherapy.

Antiangiogenic activity and pharmacogenomics of medicinal plants from traditional korean medicine

Aim. In the present study, we investigated the antiangiogenic properties of 59 plants used in traditional Korean medicine. Selected phytochemicals were investigated in more detail for their modes of action. Methods. A modified chicken-chorioallantoic-membrane (CAM) assay using quail eggs was applied to test for antiangiogenic effects of plant extracts. A molecular docking in silico approached the binding of plant constituents to the vascular endothelial growth factor receptors 1 and 2 (VEGFR1, VEGFR2). Microarray-based mRNA expression profiling was employed to correlate the 50% inhibition concentrations (IC₅₀) of a panel of 60 NCI cell lines to these phytochemicals. Results. Extracts from Acer mono leaves, Reynoutria sachalniensis fruits, Cinnamomum japonicum stems, Eurya japonica leaves, Adenophora racemosa whole plant, Caryopteris incana leaves-stems, and Schisandra chinensis stems inhibited angiogenesis more than 50% in quail eggs. Selected phytochemicals from Korean plants were analyzed in more detail using microarray-based mRNA expression profiles and molecular docking to VEGFR1 and VEGFR2. These results indicate multifactorial modes of action of these natural products. Conclusion. The antiangiogenic activity of plants used in traditional Korean medicine implicates their possible application for diseases where inhibition of blood vessel formation is desired, for example, cancer, macular degeneration, diabetic retinopathy and others.

Bystander senescence in human peritoneal mesothelium and fibroblasts is related to thrombospondin-1-dependent activation of transforming growth factor-β1

Senescence bystander effect refers to a phenomenon in which senescent cells elicit the development of senescence phenotype in their nearby young counterparts. In this paper we examined the mechanism of senescence bystander effect triggered by senescent human peritoneal mesothelial cells (HPMCs) in proliferating HPMCs and peritoneal fibroblasts (HPFBs). The results showed that conditioned medium (CM) derived from senescent HPMCs elicited a senescence response (growth inhibition coupled with increased expression of senescence-associated β-galactosidase and accumulation of histone γ-H2A.X) in either early-passage HPMCs or HPFBs. Samples of CM from senescent HPMCs contained increased amounts of numerous soluble mediators of which only transforming growth factor-β1 (TGF-β1) was able to induce senescence phenotype in the both types of peritoneal cells, likely through an induction of reactive oxygen species (ROS) and p38 mitogen-activated protein kinase (MAPK). At the same time, senescent HPMCs released increased amounts of thrombospondin-1 (TSP-1), a major activator of TGF-β1. Significantly, TSP-1 itself was unable to induce senescence phenotype in HPMCs or in HPFBs. The experiments employing anti-TSP-1 antibodies and specific TSP-1 blocking peptide revealed that neutralization of TSP-1 in CM prevented TGF-β1-dependent development of senescence phenotype. Collectively, our findings indicate that senescent HPMCs exhibit senescence-promoting activity toward neighboring young cells (HPMCs and HPFBs), and this effect is, at least partly, related to TSP-1-dependent activation and further ROS- and p38 MAPK-related activity of TGF-β1.

Celecoxib alleviates tamoxifen-instigated angiogenic effects by ROS-dependent VEGF/VEGFR2 autocrine signaling

BACKGROUND

Tamoxifen (TAM) is widely used in the chemotherapy of breast cancer and as a preventive agent against recurrence after surgery. However, extended TAM administration for breast cancer induces increased VEGF levels in patients, promoting new blood vessel formation and thereby limiting its efficacy. Celecoxib (CXB), a selective COX-2 inhibitor, suppresses VEGF gene expression by targeting the VEGF promoter responsible for its inhibitory effect. For this study, we had selected CXB as non-steroidal anti-inflammatory drug in combination with TAM for suppressing VEGF expression and simultaneously reducing doses of both the drugs.

METHODS

The effects of CXB combined with TAM were examined in two human breast cancer cell lines in culture, MCF7 and MDA-MB-231. Assays of proliferation, apoptosis, angiogenesis, metastasis, cell cycle distribution, and receptor signaling were performed.

RESULTS

Here, we elucidated how the combination of TAM and CXB at nontoxic doses exerts anti-angiogenic effects by specifically targeting VEGF/VEGFR2 autocrine signaling through ROS generation. At the molecular level, TAM-CXB suppresses VHL-mediated HIF-1α activation, responsible for expression of COX-2, MMP-2 and VEGF. Besides low VEGF levels, TAM-CXB also suppresses VEGFR2 expression, confirmed through quantifying secreted VEGF levels, luciferase and RT-PCR studies. Interestingly, we observed that TAM-CXB was effective in blocking VEGFR2 promoter induced expression and further 2 fold decrease in VEGF levels was observed in combination than TAM alone in both cell lines. Secondly, TAM-CXB regulated VEGFR2 inhibits Src expression, responsible for tumor progression and metastasis. FACS and in vivo enzymatic studies showed significant increase in the reactive oxygen species upon TAM-CXB treatment.

CONCLUSIONS

Taken together, our experimental results indicate that this additive combination shows promising outcome in anti-metastatic and apoptotic studies. In a line, our preclinical studies evidenced that this additive combination of TAM and CXB is a potential drug candidate for treatment of breast tumors expressing high levels of VEGF and VEGFR2. This ingenious combination might be a better tailored clinical regimen than TAM alone for breast cancer treatment.

Resveratrol and related stilbenes: their anti-aging and anti-angiogenic properties

Dietary stilbenes comprise a class of natural compounds that display significant biological activities of medicinal interest. Among them, their antioxidant, anti-aging and anti-angiogenesic properties are well established and subjects of numerous research endeavors. This mini-review aspires to account and present the literature reports published on research concerning various natural and synthetic stilbenes, such as trans-resveratrol. Special focus was given to most recent research findings, while the mechanisms underlying their anti-aging and anti-angiogenic effects as well as the respective signaling pathways involved were also presented and discussed.

Protective Effects of Resveratrol on TNF-α-Induced Endothelial Cytotoxicity in Baboon Femoral Arterial Endothelial Cells

Endothelial injury induced by inflammatory factors plays a critical role in the pathogenesis of cardiovascular disease. Endothelial cell (EC) apoptosis, proliferation, migration, and cellular adhesion molecule (CAM) expression contribute to the development of atherosclerosis. We investigated the effects of resveratrol (0.1-100  μ M) on the proliferation, migration, and CAM expression of primary cultures of baboon arterial endothelial cells (BAECs). In addition, we tested its effects under normal conditions as well as under inflammatory conditions induced by tumour necrosis factor-α (TNF-α) administered either by cotreatment, pretreatment, or posttreatment. Immunocytochemistry, MTT, wound-healing, and flow cytometry assays were performed. The resveratrol treatment significantly enhanced BAEC proliferation and attenuated TNF-α-induced impairment of proliferation at the optimal doses of 1-50 µM. Resveratrol at a high dose (100  μ M) and TNF-α impaired BAEC migration, while low doses of resveratrol (1-50  μ M) attenuated TNF-α-induced impairment of BAEC migration. Moreover, resveratrol inhibited TNF-α-induced ICAM-1 and VCAM-1 expression. Taken together, our results suggest that the resveratrol protects BAECs after inflammatory stimulation as well as ameliorates inflammatory effects at low concentrations. Consequently, resveratrol should be considered as a candidate drug for the prevention and treatment of inflammatory vascular diseases.