Resveratrol is a naturally occurring polyphenol, which causes apoptosis in cultured cancer cells. We describe a cell surface resveratrol receptor on the extracellular domain of hetero-dimeric alphaVbeta3 integrin in MCF-7 human breast cancer cells. This receptor is linked to induction by resveratrol of extracellular-regulated kinases 1 and 2 (ERK1/2)- and serine-15-p53-dependent phosphorylation leading to apoptosis. The integrin receptor is near the Arg-Gly-Asp (RGD) recognition site on the integrin; an integrin-binding RGD peptide inhibits induction by resveratrol of ERK1/2- and p53-dependent apoptosis. Antibody (Ab) to integrin alphaVbeta3, but not to alphaVbeta5, inhibits activation by resveratrol of ERK1/2 and p53 and consequent apoptosis in estrogen receptor-alpha (ERalpha) positive MCF-7, and ERalpha-negative MDA-MB231 cells. Resveratrol is displaced from the purified integrin by an RGD, but not RGE, peptide, and by alphaVbeta3 integrin-specific Ab. Resveratrol action is blocked by siRNAbeta3, but not by siRNAalphaV. [14C]-Resveratrol binds to commercially purified integrin alphaVbeta3 and to alphaVbeta3 prepared from MCF-7 cells; binding of [14C]-resveratrol to the beta3, but not to the alphaV monomer, is displaced by unlabeled resveratrol. In conclusion, binding of resveratrol to integrin alphaVbeta3, principally to the beta3 monomer, is essential for transduction of the stilbene signal into p53-dependent apoptosis of breast cancer cells.

Objective: To investigate the process by which quercetin suppresses atherosclerosis by upregulating MST1-mediated autophagy in RAW264.7 macrophages. Methods: An in vitro foam cell model was established by culturing RAW264.7 macrophages with oxidized low-density lipoprotein (ox-LDL). The cells were treated with quercetin alone or in combination with the autophagy inhibitor, 3-methyladenine, and autophagy agonist, rapamycin. Cell viability was detected with a CCK-8 kit. Lipid accumulation was detected by oil red O staining, senescence was detected by SA-β-gal (senescence-associated β-galactosidase) staining, reactive oxygen species were detected by ROS assay kit. Autophagosomes and mitochondria were detected by transmission electron microscope (TEM), and expression of MST1, LC3-II/I, Beclin1, Bcl-2, P21, and P16 were detected by immunofluorescence and Western blot. Results: Ox-LDL induced RAW264.7 macrophage-derived foam cell formation, reduced survival, aggravated cell lipid accumulation, and induced a senescence phenotype. This was accompanied by decreased formation of autophagosome; increased expression of P53, P21, and P16; and decreased expression of LC3-II/I and Beclin1. After intervention with quercetin, the cell survival rate was increased, and lipid accumulation and senescence phenotype were reduced. Furthermore, the expression of LC3-II/I and Beclin1 were increased, which was consistent with the ability of quercetin to promote autophagy. Ox-LDL also increased the expression of MST1, and this increase was blocked by quercetin, which provided a potential mechanism by which quercetin may protect foam cells against age-related detrimental effects. Conclusion: Quercetin can inhibit the formation of foam cells induced by ox-LDL and delay senescence. The mechanism may be related to the regulation of MST1-mediated autophagy of RAW264.7 cells.

The aim of this study was to investigate the mechanisms through which quercetin protects against atherosclerosis (AS) in apoE −/− mice by regulating the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), cluster of differentiation 36 (CD36), peroxisome proliferator-activated receptor γ (PPARγ), liver X receptor α (LXRα) and ATP binding cassette transporter A1 (ABCA1). We established an animal model of high-fat diet induced AS using apoE −/− mice. H&E, Oil Red O and Masson's trichrome staining were performed on aortic sinus and liver tissue sections to evaluate the histopathology, lipid accumulation and collagen deposition, respectively. Filipin staining was performed to detect free cholesterol (FC) in the aortic sinus. ELISA was performed to measure the serum levels of lipids including total cholesterol (TC), triglyceride (TG), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C) and oxidized low-density lipoprotein (oxLDL), as well as the levels of inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10. Western blot analysis was performed to analyze the protein expression levels of PCSK9, CD36, PPARγ, LXRα and ABCA1 in both the aorta and liver tissue. H&E staining revealed the presence of atherosclerotic plaques in the aortic sinus. Oil Red O staining revealed the existence of massive red-stained lipids in the aortic sinus and Masson's trichrome staining revealed decreased collagen fibers and increased plaque instability. Filipin staining revealed that free cholesterol levels in the aorta sinus were increased. In addition, H&E staining suggested hepatocyte structural disorder in the model group, and Oil Red O staining revealed a cytoplasm filled with lipid droplets, which contained a large amount of red-stained lipids. Masson's trichrome staining revealed that the liver tissue of the model group had fewer collagen fibers compared with that of the control group. Moreover, the mice in the model group had higher serum TC, LDL-C, oxLDL, TNF-α and IL-6 levels, and lower IL-10 levels. The protein expression levels of PCSK9 and CD36 were increased, while those of PPARγ, LXRα and ABCA1 were decreased in the aortas and livers of the model group mice. However, treatment with quercetin attenuated all these effects. On the whole, these results demonstrate that quercetin prevents the development of AS in apoE −/− mice by regulating the expression of PCSK9, CD36, PPARγ, LXRα and ABCA1.

Conditionally replicating adenoviruses (CRAd) can replicate specifically in cancer cells and lyse them. The CRAds were widely used in the preclinical and clinical studies of cancer therapy. We hypothesize that more precisely regulated replication of CRAds may further improve the vector safety profile and enhance its antitumor efficacy.

The present study examined the involvement of autophagy as a mechanism in the protective effect of quercetin (QUE) on atherosclerosis (AS) in ApoE−/− mice. An AS model was established by feeding ApoE−/− mice a high-fat diet (HFD). Mice were divided into four experimental groups: The model, QUE, 3-methyladenine (3-MA) and QUE + 3-MA groups. Additionally, age-matched wild-type C57BL/6 mice were used as a Control group. Autophagosomes in the aorta were examined using a transmission electron microscope. Aorta pathology, serum lipid accumulation and collagen deposition were determined by hematoxylin and eosin, Oil Red O and Masson staining, respectively. The levels of cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-18 (IL-18) were measured using ELISA assays. Protein levels of mTOR, microtubule associated protein 1 light chain 3a (LC3), P53 and cyclin dependent kinase inhibitor 1A (P21) in the aorta were analyzed using western blotting. ApoE−/− mice which were fed HFD exhibited substantial AS pathology, no autophagosomes, higher levels of TNF-α, IL-1β, IL-18 and mTOR and lower ratios of LC3 II/I. All these alterations were ameliorated and aggravated by QUE and 3-MA treatment, respectively. The inhibition of AS by QUE may be associated with the enhancement of autophagy and upregulation of P21 and P53 expression.

Quercetin is a flavonoid that has anti-inflammatory, anti-oxidant and lipid metabolic effects. It has also been reported to reduce the risk of cardiovascular disease. The present study measured the effects of quercetin on the expression of ATP-binding cassette transporter 1 (ABCAl), ATP-binding cassette sub-family G member 1 (ABCG1), liver X receptor-α (LXR-α), proprotein convertase subtilisin/kexin type 9 (PCSK9), p53, p21 and p16 induced by oxidized low density lipoprotein (ox-LDL). RAW264.7 macrophages were exposed to ox-LDL with or without 20 µmol/l quercetin and cell proliferation and senescence were quantified using β-gal staining. Superoxide dismutase (SOD), malondialdehyde (MDA) and lipid droplets were measured in the cytoplasm using oil red staining, while intracellular and total cholesterol (TC) were measured using filipin staining and a TC kit. Immunofluorescent studies and western blot analysis were performed to quantify the expression of ABCAl, ABCG1, LXR-α, PCSK9, p53, p21 and p16. Quercetin increased RAW264.7 cell viability and reduced lipid accumulation, senescence, lipid droplets, intracellular cholesterol and TC. It was concluded that quercetin inhibits ox-LDL-induced lipid droplets in RAW264.7 cells by upregulation of ABCAl, ABCG1, LXR-α and downregulation of PCSK9, p53, p21 and p16.

Conditionally replicating adenovirus (CRAd) has demonstrated to be safe in clinical studies. We generated a triple-regulated p53-armed CRAd, SG600-p53, in which the partially deleted E1a and E1b genes are regulated under the human telomerase reverse transcriptase promoter and the hypoxia response element. SG600-p53 was proven to be effective both in vitro and in vivo. In this study, the preclinical safety profiles of SG600-p53 in animal models were investigated. SG600-p53 had no adverse effects on mouse behavioral and nervous systems at 1.0 x 10(11) viral particles (VP)/kg, 2.0 x 10(11) VP/kg and 4.0 x 10(11) VP/kg doses, and on cat cardiovascular and respiratory systems at 2.0 x 10(10) VP/kg, 4.0 x 10(10) VP/kg, and 8.0 x 10(10) VP/kg doses. In acute toxicity test in mice, the maximum tolerated dose (2.5 x 10(13) VP/kg) induced cachexia, decreased activity, and eye closure in 9/20 mice which could be self-resolved within 30 min. Sensitized by five repeated ip injections at 1.0 x 10(10) VP/kg each ip and excitated by one iv injection at 1.0 x 10(11) VP/kg, guinea pigs did not show any sign of systemic anaphylaxis. In repeat-dose toxicological studies, the no-observable-adverse-effect levels of SG600-p53 in rats (1.0 x 10(11) VP/kg) and cynomolgus monkeys (5.0 x 10(11) VP/kg) were 12-fold and 60-fold of the proposed clinical dose, respectively. Intramuscular injections of SG600-p53 in cynomolgus monkeys caused inflammation at injection sites, which was alleviative at the end of observation period. The anti-virus antibody was produced in animal sera and decreased gradually 4 weeks later. No histopathological changes were found by bone marrow examination. Our data in different animal models suggest that SG600-p53 is a safe antitumor therapeutic agent.

The purpose of the current study was to investigate the mechanism by which fisetin improves atherosclerosis (AS) by regulating lipid metabolism and senescence in apolipoprotein E-deficient (apoE -/- ) mice. An AS model was established by feeding apoE -/- mice a high-fat diet. Mice were randomly divided into the model group (n=18), the fisetin group (n=18) and the atorvastatin group (n=18). The control group (n=18) was composed of wild-type C57BL/6 mice of the same age and genetic background. The fisetin and atorvastatin groups were respectively treated with aqueous solutions of fisetin (12.5 mg/kg) and atorvastatin (2 mg/kg) via oral gavage daily for 12 weeks. The pathological morphology, lipid accumulation, collagen deposition of the aortic sinus were observed, serum lipids, superoxide dismutase (SOD) and malondialdehyde (MDA) levels and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were measured in the peripheral blood serum. Additionally, the expressions of proprotein convertase subtilisin/kexin type 9 (PCSK9), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), tumor suppressor protein p53 (p53), cyclin-dependent kinase inhibitor 1A (p21) and multiple tumor suppressor-1 (p16) were analyzed in the aorta. The results of the current study indicated that compared with the control group, a large area of AS plaque in the aortic sinus that contained a large amount of red-stained lipids and decreased collagen fiber content were found in the model group, which exhibited higher total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), oxidized low-density lipoprotein (ox-LDL) and MDA levels; higher ALT and AST activities, lower high-density lipoprotein cholesterol (HDL-C) and SOD levels and increased expression levels of PCSK9, LOX-1, p53, p21 and p16. Fisetin is a phytochemical and bioflavonoid that serves a potential role in chronic diseases including AS, obesity, diabetes and cancer due to its wide biological activities, such as regulating lipid metabolism and anti-aging, anti-oxidation and anti-inflammatory. Atorvastatin is recognized as a first-line treatment drug for AS; therefore it was used as a positive control in the current study. Following fisetin and atorvastatin treatment, both the AS plaque and the lipid accumulation in the aortic sinus were significantly reduced, and the expressions of PCSK9, LOX-1 and aging markers, including p53, p21 and p16 were downregulated.