The natural compound magnolol inhibits invasion and exhibits potential in human breast cancer therapy

Invasion and metastasis are the main causes of treatment failure and death in breast cancer. Thus, novel invasion-based therapies such as those involving natural agents are urgently required. In this study, we examined the effects of magnolol (Mag), a compound extracted from medicinal herbs, on breast cancer cells in vitro and in vivo. Highly invasive cancer cells were found to be highly sensitive to treatment. Mag markedly inhibited the activity of highly invasive MDA-MB-231 cells. Furthermore, Mag significantly downregulated matrix metalloproteinase-9 (MMP-9) expression, an enzyme critical to tumor invasion. Mag also inhibited nuclear factor-κB (NF-κB) transcriptional activity and the DNA binding of NF-κB to MMP-9 promoter. These results indicate that Mag suppresses tumor invasion by inhibiting MMP-9 through the NF-κB pathway. Moreover, Mag overcame the promoting effects of phorbol 12-myristate 13-acetate (PMA) on the invasion of MDA-MB-231 cells. Our findings reveal the therapeutic potential and mechanism of Mag against cancer.

Curcumin-loaded nanoparticles enhance apoptotic cell death of U2OS human osteosarcoma cells through the Akt-Bad signaling pathway

Curcumin has potential anticancer activity and has been shown to be involved in several signaling pathways including differentiation and apoptosis. Our previous study showed that water-soluble PLGA curcumin nanoparticles (Cur-NPs) triggered apoptotic cell death through regulation of the function of MDR1 and the production of reactive oxygen species (ROS) in cisplatin-resistant human oral cancer CAR cells. In this study, we investigated the anti-proliferative effects of Cur-NPs on human osteosarcoma U2OS cells. The morphology of Cur-NPs showed spherical shape by TEM analysis. The encapsulation efficiency of curcumin in Cur-NPs prepared by single emulsion was 90.5 ± 3.0%. Our results demonstrated that the curcumin fragments on the mass spectrum of Cur-NPs and the peaks of curcumin standard could be found on the Cur-NPs spectrum by 1H-NMR spectra analysis. Cur-NPs induced anti-proliferative effects and apoptosis in U2OS cells. Compared to the untreated U2OS cells, more detectable amount of Cur-NPs was found inside the treated U2OS cells. Cur-NPs induced DNA fragmentation and apoptotic bodies in U2OS cells. Both the activity and the expression levels of caspases-3/-7 and caspase-9 were elevated in the treated U2OS cells. Cur-NPs upregulated the protein expression levels of cleaved caspase-3/caspase-9, cytochrome c, Apaf-1 and Bad and downregulated the protein expression level of p-Akt in U2OS cells. These results suggest Cur-NPs are effective in enhancing apoptosis in human osteosarcoma cells and thus could provide potential for cancer therapeutics.

Luteolin 8-C-β-fucopyranoside inhibits invasion and suppresses TPA-induced MMP-9 and IL-8 via ERK/AP-1 and ERK/NF-κB signaling in MCF-7 breast cancer cells

Matrix metalloproteinase 9 (MMP-9) and interleukin-8 (IL-8) play major roles in tumor progression and invasion of breast cancer cells. The present study was undertaken to investigate the inhibitory mechanism of cell invasion by luteolin 8-C-β-fucopyranoside (named as LU8C-FP), a C-glycosylflavone, in human breast cancer cells. We investigated whether LU8C-FP would inhibit MMP-9 activation and IL-8 expression in 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated MCF-7 breast cancer cells. LU8C-FP suppressed TPA-induced MMP-9 and IL-8 secretion and mRNA expression via inhibition of the MAPK signaling pathway and down-regulation of nuclear AP-1 and NF-κB. TPA-induced phosphorylation of ERK 1/2 was suppressed by LU8C-FP, whereas JNK and p38 MAPK phosphorylation were unaffected. In addition, LU8C-FP blocked the ERK 1/2 pathways following expression of MMP-9 and IL-8. These results suggest LU8C-FP may function to suppress invasion of breast cancer cells through the ERK/AP-1 and ERK/NF-κB signaling cascades.

Luteolin inhibits migration of human glioblastoma U-87 MG and T98G cells through downregulation of Cdc42 expression and PI3K/AKT activity

Luteolin (3′,4′,5,7-tetrahydroxyflavone) is a common flavonoid in many types of plants and has several beneficial biological effects, including anti-inflammation, anti-oxidant, and anti-cancer properties. However, the detail mechanisms of luteolin in suppressing tumor invasion and metastasis are poorly understood. Here, we investigated the effects of luteolin on suppressing glioblastoma tumor cell invasion and migration activity. Under the non-cytotoxic doses (15 and 30 μM), luteolin exhibited an inhibitory effect on migration and invasion in U-87 MG and T98G glioblastoma cells. Additionally, filopodia assembly in U-87 MG cells was markedly suppressed after luteolin treatment. The treatment of luteolin also showed a decrease of Cdc42 (cell division cycle 42) protein levels and reduced PI3K/AKT activation, whereas there was no association between this decrease and phosphorylated ERK or altered transcription levels of Cdc42. Over expression of constitutive Cdc42 (Q61L) using transient transfection in U-87 MG cells induced a partial cell migration, but did not affected the degradation of the protein levels of Cdc42 after luteolin treatment. Moreover, inhibition of the proteaosome pathway by MG132 caused a significant recovery in the migration ability of U-87 MG cells and augmented the Cdc42 protein levels after luteolin treatment, suggesting that pharmacological inhibition of migration via luteolin treatment is likely to preferentially facilitate the protein degradation of Cdc42. Taken together, the study demonstrated that flavonoids of luteolin prevent the migration of glioblastoma cells by affecting PI3K/AKT activation, modulating the protein expression of Cdc42 and facilitating their degradation via the proteaosome pathway.

Inhibitory effects of dried longan (Euphoria longana Lam.) seed extract on invasion and matrix metalloproteinases of colon cancer cells

The critical step in colorectal cancer progression and associated mortality is cancer invasion, which depends on two key gelatinase enzymes, matrix metalloproteinases-2 and -9. Dried longan ( Euphoria longana Lam.) seed is a rich natural source of antioxidant polyphenols.This study evaluated the effect of dried longan seeds on colon cancer cell invasion via gelatinase function and expression. Three dried longan seed fractions were collected by Sephadex LH-20 column chromatography. They showed a potent inhibitor on colorectal cancer cell invasion and gelatinase activity. The antigelatinase activities of fractions 1 and 2 were a direct effect via Zn²⁺ chelation, whereas fraction 3 modulated indirectly through suppression of zymogen activators. Among the fractions, only fraction 3 reduced the gelatinase expression, which was correlated with the levels of tissue inhibitor of metalloproteinase-1 and may as well involve the p38 mitogen-activated protein kinases and the c-Jun N-terminal kinase signaling pathways. This primary research has manifested and encouraged the anticancer properties of dried longan seed extracts with potential inhibitory effects on cancer cell invasion as well as antigelatinase activity and expression in colon cancer cells.

Quercitrin protects skin from UVB-induced oxidative damage

Exposure of the skin to ultraviolet B (UVB) radiation causes oxidative damage to skin, resulting in sunburn, photoaging, and skin cancer. It is generally believed that the skin damage induced by UV irradiation is a consequence of generation of reactive oxygen species (ROS). Recently, there is an increased interest in the use of natural products as chemopreventive agents for non-melanoma skin cancer (NMSC) due to their antioxidants and anti-inflammatory properties. Quercitrin, glycosylated form of quercetin, is the most common flavonoid in nature with antioxidant properties. The present study investigated the possible beneficial effects of quercitrin to inhibit UVB irradiation-induced oxidative damage in vitro and in vivo. Our results showed that quercitrin decreased ROS generation induced by UVB irradiation in JB6 cells. Quercitrin restored catalase expression and GSH/GSSG ratio reduced by UVB exposure, two major antioxidant enzymes, leading to reductions of oxidative DNA damage and apoptosis and protection of the skin from inflammation caused by UVB exposure. The present study demonstrated that quercitrin functions as an antioxidant against UVB irradiation-induced oxidative damage to skin.

Silibinin inhibits TPA-induced cell migration and MMP-9 expression in thyroid and breast cancer cells

Matrix metalloproteinases (MMPs) play an important role in cancer metastasis, cell migration and invasion. Herein, we investigated the effects of silibinin on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cell migration and MMP-9 expression in thyroid and breast cancer cells. Our results revealed that the levels of MMP-9 mRNA and protein expression were significantly increased by TPA but not MMP-2 in TPC-1 and MCF7 cells. To verify the regulatory mechanism of TPA-induced MMP-9 expression, we treated TPC-1 and MCF7 cells with the MEK1/2 inhibitor, UO126, and TPA-induced MMP-9 expression was significantly decreased. We also found that TPA-induced cell migration and MMP-9 expression was significantly decreased by silibinin. In addition, TPA-induced phosphorylation of MEK and ERK was also inhibited by silibinin. Taken together, we suggest that silibinin suppresses TPA-induced cell migration and MMP-9 expression through the MEK/ERK-dependent pathway in thyroid and breast cancer cells.

Inhibition of matrix metalloproteinase-9 expression by docosahexaenoic acid mediated by heme oxygenase 1 in 12-O-tetradecanoylphorbol-13-acetate-induced MCF-7 human breast cancer cells

Matrix metalloproteinase-9 (MMP-9) plays a crucial role in tumor metastasis. Previous studies showed that polyunsaturated fatty acids exhibit an anti-cancer effect in various human carcinoma cells, but the effect of docosahexaenoic acid (DHA) and linoleic acid (LA) on metastasis of breast cancer cells is not fully clarified. We studied the anti-metastasis potential of DHA and LA in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MCF-7 cells. We found that TPA (100 ng/ml) induced MMP-9 enzyme activity both dose- and time-dependently, and 200 μM DHA and LA significantly inhibited MMP-9 mRNA and protein expression, enzyme activity, cell migration, and invasion. Treatment with PD98059 (10 μM), wortmannin (10 μM), and GF109203X (0.5 μM) decreased TPA-induced MMP-9 protein expression and enzyme activity. TPA-induced activation of ERK1, Akt, and PKCδ was attenuated by DHA, whereas LA attenuated only ERK1 activation. GF109203X also suppressed ERK1 activation. EMSA showed that DHA, LA, PD98059, and wortmannin decreased TPA-induced NF-κB and AP-1 DNA-binding activity. Furthermore, DHA rather than LA dose-dependently increased HO-1 expression. HO-1 siRNA alleviated the inhibition by DHA of TPA-induced MMP-9 protein expression and enzyme activity in MCF-7 cells, and HO-1 knockdown reversed the DHA inhibition of cell migration. These results suggest that DHA and LA have both similar and divergent signaling pathways in the suppression of TPA-induced MCF-7 metastasis.

Role of N-acetylcysteine and GSH redox system on total and active MMP-2 in intestinal myofibroblasts of Crohn's disease patients

PURPOSE

Intestinal subepithelial myofibroblasts (ISEMFs)(1) are the predominant source of matrix metalloproteinase-2 (MMP-2) in gut, and a decrease in glutathione/oxidized glutathione (GSH/GSSG) ratio, intracellular redox state index, occurs in the ISEMFs of patients with Crohn's disease (CD). The aim of this study is to demonstrate a relationship between MMP-2 secretion and activation and changes of GSH/GSSG ratio in ISEMFs stimulated or not with tumor necrosis factor alpha (TNFα).

METHODS

ISEMFs were isolated from ill and healthy colon mucosa of patients with active CD. Buthionine sulfoximine, GSH synthesis inhibitor, and N-acetylcysteine (NAC), precursor of GSH synthesis, were used to modulate GSH/GSSG ratio. GSH and GSSG were measured by HPLC and MMP-2 by ELISA Kit.

RESULTS

In cells, stimulated or not with TNFα, a significant increase in MMP-2 secretion and activation, related to increased oxidative stress, due to low GSH/GSSG ratio, was detected. NAC treatment, increasing this ratio, reduced MMP-2 secretion and exhibited a direct effect on the secreted MMP-2 activity. In NAC-treated and TNFα-stimulated ISEMFs of CD patients' MMP-2 activity were restored to physiological value. The involvement of c-Jun N-terminal kinase pathway on redox regulation of MMP-2 secretion has been demonstrated.

CONCLUSION

For the first time, in CD patient ISEMFs, a redox regulation of MMP-2 secretion and activation related to GSH/GSSG ratio and inflammatory state have been demonstrated. This study suggests that compounds able to maintain GSH/GSSG ratio to physiological values can be useful to restore normal MMP-2 levels reducing in CD patient intestine the dysfunction of epithelial barrier.

Curcumin suppresses the TPA-induced invasion through inhibition of PKCα-dependent MMP-expression in MCF-7 human breast cancer cells

Curcumin (diferuloylmethane) is a polyphenol derived from the plant turmeric (Curcuma longa), which is commonly used as a spice. Although anti-carcinogenic, anti-oxidant, anti-inflammation, and anti-angiogenic properties have been reported, the effect of curcumin on breast cancer metastasis is unknown. Matrix metalloproteinase-9 (MMP-9) is a major component in cancer cell invasion. In this study, we investigated the inhibitory effect of curcumin on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MMP-9 expression and cell invasion and the molecular mechanisms involved in MCF-7 cells. Our results showed that curcumin inhibits TPA-induced MMP-9 expression and cell invasion through suppressing NF-κB and AP-1 activation. Also, curcumin strongly repressed the TPA-induced phosphorylation of p38 and JNK and inhibited TPA-induced translocation of PKCα from the cytosol to the membrane, but did not affect the translocation of PKCδ. These results indicate that curcumin-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of the PKCα, MAPK and NF-κB/AP-1 pathway in MCF-7 cells. Curcumin may have potential value in restricting breast cancer metastasis.

Toll-like receptor-9 agonists increase cyclin D1 expression partly through activation of activator protein-1 in human oral squamous cell carcinoma cells

Increasing evidence suggests that malignant transformation can result from chronic infection, and Toll-like receptors (TLRs) may play an important role in this process. We have previously reported that the increased expression of TLR-9 is associated with tumor cell proliferation in oral cancer. However, the mechanisms involved have not been elucidated. The aim of this study was to investigate whether CpG-oligodeoxynucleotides (CpG-ODN), a special TLR-9 agonist, is able to exert the proliferation-promoting effect in human oral squamous cell carcinoma (OSCC), and to explore the possible underlying molecular mechanism. Flow cytometry, MTT, and colony formation assay were used to evaluate cell proliferation and cell cycle distribution. The mRNA and protein levels were analyzed by quantitative RT-PCR and Western blot assay. Luciferase reporter gene, EMSA, and ChIP assays were used to detect the activity of activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) in HB cells. Results showed that CpG-ODN could stimulate proliferation of HB cells in a dose- and time-dependent manner with a promoted G(1) /S cell cycle progression. Increased cyclin D1 expression was detected in the nuclear region after CpG-ODN treatment. Moreover, CpG-ODN promoted nuclear translocation and activation of AP-1, which appeared to be required for TLR-9-mediated cyclin D1 expression and subsequently cell proliferation, but seemed to have little impact on NF-κB activity. Our results indicate that CpG-ODN stimulates tumor cell proliferation through TLR-9-mediated AP-1-activated cyclin D1 expression in OSCC HB cells. Pharmacologic inhibition of the TLR-9/AP-1/cyclin D1 pathway may be a new therapeutic approach for prevention as well as treatment of OSCC.

Effects of Luteolin on Liver, Kidney and Brain in Pentylentetrazol-Induced Seizures: Involvement of Metalloproteinases and NOS Activities

OBJECTIVE

Flavonoids are an important group of recognized antioxidants in plants. Luteolin (LUT) is a natural flavonoid in the plant kingdom. This study was aimed to investigate the effects of the LUT in the liver, kidney and brain of pentylentetrazol (PTZ)-induced seizure and the relationship between nitric oxide synthases (iNOS, eNOS) and matrix metalloproteinases (MMP2, MMP9).

MATERIALS AND METHODS

LUT (10 mg/kg) was given intraperitoneally during two weeks prior to seizure induction. A single dose PTZ 80 mg/kg i.p. was administered and seizures were observed and evaluated with regard to latency, frequency and stage for one hour.

RESULTS

Seizure frequen cy after PTZ administration was significantly decreased in LUT pretreated rats (p<0.05). An increase of immunhistochemical reactions of iNOS and MMP2, but a decrease of eNOS activity, were observed in rat hippocampus and peripheral tissues during the PTZ induced seizures. LUT pretreatment reversed the iNOS and MMP2 activity to the control levels and significantly increased the eNOS activity (p<0.001).

CONCLUSION

LUT seems to have an effective role in reducing the seizure frequency and a protective role on peripheral organ injury in animal models of seizure. The protective effect of LUT in seizures and the seizure induced peripheral tissue damage warrant further investigations.

Mediterranean diet polyphenols reduce inflammatory angiogenesis through MMP-9 and COX-2 inhibition in human vascular endothelial cells: a potentially protective mechanism in atherosclerotic vascular disease and cancer

Diets with high content of antioxidant polyphenols are associated with low prevalence of cardiovascular diseases and cancer. Inflammatory angiogenesis is a key pathogenic process both in cancer and atherosclerosis, and is tightly regulated by the proinflammatory enzyme cyclooxygenase (COX)-2 and the matrix degrading enzymes matrix metalloproteinases (MMPs). We studied the effects of antioxidant polyphenols from virgin olive oil (oleuropein and hydroxytyrosol) and red wine (resveratrol and quercetin) on endothelial cell angiogenic response in vitro, and explored underlying mechanisms. Cultured endothelial cells were pre-incubated with 0.1-50 μmol/L polyphenols before stimulation with phorbol myristate acetate (PMA). All tested polyphenols reduced endothelial cell tube formation on matrigel and migration in wound healing assays. The reduced angiogenesis was associated with the inhibition of PMA-induced COX-2 protein expression and prostanoid production, as well as MMP-9 protein release and gelatinolytic activity. These effects were accompanied by a significant reduction in the stimulated intracellular reactive oxygen species levels and in the activation of the redox-sensitive transcription factor nuclear factor (NF)-κB. Our findings reveal that olive oil and red wine polyphenols reduce inflammatory angiogenesis in cultured endothelial cells, through MMP-9 and COX-2 inhibition, supporting a potential protective role for dietary polyphenols in atherosclerotic vascular disease and cancer.

Scutellarin Attenuates Human-Neutrophil-Elastase-Induced Mucus Production by Inhibiting the PKC-ERK Signaling Pathway in Vitro and in Vivo

The aim of this study was to investigate the influence of scutellarin on mucus production induced by human neutrophil elastase (HNE) and the possible in vitro and in vivo mechanisms. To this purpose, cells were incubated with saline, scutellarin or gefitinib for 60 min and exposed to 0.1 μM HNE for 24 h. After being pretreated respectively with saline, scutellarin or gefitinib, rats were challenged intratracheally with HNE by means of nebulization for 30 days. The expression of mucin (MUC) 5AC, protein kinase C (PKC), and extracellular signal-regulated kinase 1/2 (ERK1/2) was assessed by ELISA, RT-PCR or Western blotting. The results showed that scutellarin inhibited MUC5AC mRNA and protein expressions induced by HNE in a concentration-dependent manner in vitro. In the in vivo model, scutellarin significantly attenuated MUC5AC mRNA expression and goblet cell hyperplasia in rats treated with HNE for 30 days, as well as decreased the phosporylation of PKC and ERK1/2 compared to the HNE control group. Therefore, our study showed that scutellarin could prevent mucus hypersecretion by inhibiting the PKC-ERK signaling pathway. Inhalation scutellarin may be valuable in the treatment of chronic inflammatory lung disease.

Quercetin in elimination of tumor initiating stem-like and mesenchymal transformation property in head and neck cancer

BACKGROUND

Previously, we enriched a subpopulation of head and neck cancer-derived tumor initiating cells (HNC-TICs) presented high tumorigenic, chemo-radioresistant, and coupled with epithelial-mesenchymal transition (EMT) properties. The purpose of this study was to investigate the therapeutic effect and molecular mechanisms of quercetin on HNC-TICs.

METHOD

ALDH1 activity of head and neck cancer cells with quercetin treatment was assessed by the Aldefluor assay flow cytometry analysis. Self-renewal, invasiveness, and EMT capability of HNC-TICs with different doses of quercetin was presented.

RESULTS

We first observed that the treatment of quercetin significantly downregulated the ALDH1 activity of head and neck cancer cells in a dose-dependent manner (p < .05). Moreover, quercetin reduced self-renewal property and stemness signatures expression in head and neck cancer-derived sphere cells. The migration ability of head and neck cancer-derived sphere cells was lessened under quercetin treatment partially due to the decreased productions of Twist, N-cadherin, and vimentin.

CONCLUSION

Quercetin suppressing HNC-TICs characteristics may therefore be valuable therapeutics clinically in combination with standard treatment modalities.

Effects of microcystin-LR exposure on matrix metalloproteinase-2/-9 expression and cancer cell migration

This study assessed the effects of microcystin-LR (MC-LR) exposure on matrix metalloproteinases (MMPs) expression and cancer cell migration. After male mice were orally administered with different concentrations of MC-LR for 270 d, histopathologic observation revealed an obvious hepatic lymphocyte infiltration or fatty degeneration. Immunohistochemical staining and enzyme-linked immunosorbent assay demonstrated that MC-LR treatment (even at 1 nM) caused up-regulated expressions of hepatic MMP-2/-9. Quantitative reverse-transcriptase PCR showed that the exposure to 80 nM MC-LR induced an increase of MMP-2/-9 mRNA levels by 1.0 and 1.9 fold. Breast cancer cells (MDA-MB-435s) were also cultured with MC-LR solutions and a wound healing assay demonstrated that MC-LR posed a time/dose-dependent stimulation effect on migration of the cancer cells. Gelatin electrophoresis and quantitative PCR showed significant increases in cellular MMP-2/-9 expressions after MC-LR exposure. This study indicated that chronic exposure to MC-LR could alter MMP-2/-9 expressions and stimulate cancer cell migration.

Doxycycline-mediated protective effect against focal cerebral ischemia-reperfusion injury through the modulation of tight junctions and PKCδ signaling in rats

The strategy for the development of effective and safe neuroprotective agents has great potential to reduce cerebral ischemia-reperfusion injury and improve the functional outcome in stroke patients. Recently, doxycycline, a tetracycline antibiotic, has been shown to have neuroprotective efficiency in reduction of a variety of ischemia-reperfusion injuries as well as ischemic brain damage. We used the rat models of middle cerebral artery occlusion (MCAO) and reperfusion to investigate the effects of treatments with doxycycline against the blood-brain barrier (BBB) leakage at 3, 12, 72, and 120 h of reperfusion. Male Sprague-Dawley rats were subjected to MCAO for 2 h followed by reperfusion for 3, 12, 72, and 120 h and received either doxycycline (45 mg/kg) or saline. The results showed that the treatment of doxycycline significantly reduced the BBB leakage and cerebral infarct volume, which were proved by Evans blue assay and TTC staining. Real-time PCR, immunohistochemistry, and western blot assay verified that the administration of doxycycline significantly up-regulated the expression of tight junction claudin-5, occludin, and ZO-1 from 3 to 120 h after reperfusion. The results of real-time PCR, western blot, and gelatin zymography analyses revealed that the gene and protein expression and activities of matrix metalloproteinases (MMPs) MMP-2 and MMP-9 were significantly elevated in a different time-dependent manner after ischemia-reperfusion but significantly inhibited by doxycycline treatment. Moreover, doxycycline could also significantly down-regulate the expression of PKCδ mRNA and protein after ischemia-reperfusion. These results suggested that the protective effects of doxycycline against BBB damage induced by reperfusion might be related to the up-regulation of tight junction proteins and inhibition of MMP-2, MMP-9, and PKCδ.

Quercetin accumulates in nuclear structures and triggers specific gene expression in epithelial cells

Quercetin is a flavonol modifying a number of cell processes in different cell lines. Here, we present evidence that nonconjugated quercetin enters cells possibly via organic anion transporter polypeptides and quickly accumulates in the nucleus where it concentrates at distinct foci. Furthermore, it induces major transcriptional events with a high number of transcripts being modified over time and about 2200 transcripts being continuously influenced by the agent. The latter transcripts are related to cell cycle and adhesion, xenobiotic metabolism, immune-related factors and transcription. In addition, quercetin up-regulates the expression of estrogen receptors α and β. The overall outcome on cell fate is reflected by an inhibition of cell proliferation, cell cycle arrest in the G1 phase and reduction of the cells' migratory potential due to actin cytoskeleton disorganization. Finally, we report that the flavonol modifies the transcription and/or activity of numerous transcription factors. In conclusion, our data support the idea that quercetin may actively accumulate in discrete cell structures and exert more than just antioxidant actions on epithelial cells by regulating mechanisms related to gene transcription.

Effects of flavonoids and other polyphenols on inflammation

Flavonoids are a family of polyphenolic compounds which are widespread in nature (vegetables) and are consumed as part of the human diet in significant amounts. There are other types of polyphenols, including, for example, tannins and resveratrol. Flavonoids and related polyphenolic compounds have significant antiinflammatory activity, among others. This short review summarizes the current knowledge on the effects of flavonoids and related polyphenolic compounds on inflammation, with a focus on structural requirements, the mechanisms involved, and pharmacokinetic considerations. Different molecular (cyclooxygenase, lipoxygenase) and cellular targets (macrophages, lymphocytes, epithelial cells, endothelium) have been identified. In addition, many flavonoids display significant antioxidant/radical scavenging properties. There is substantial structural variation in these compounds, which is bound to have an impact on their biological profile, and specifically on their effects on inflammatory conditions. However, in general terms there is substantial consistency in the effects of these compounds despite considerable structural variations. The mechanisms have been studied mainly in myeloid cells, where the predominant effect is an inhibition of NF-κB signaling and the downregulation of the expression of proinflammatory markers. At present there is a gap in knowledge of in vitro and in vivo effects, although the pharmacokinetics of flavonoids has advanced considerably in the last decade. Many flavonoids have been studied for their intestinal antiinflammatory activity which is only logical, since the gastrointestinal tract is naturally exposed to them. However, their potential therapeutic application in inflammation is not restricted to this organ and extends to other sites and conditions, including arthritis, asthma, encephalomyelitis, and atherosclerosis, among others.

Inhibitory effect of phytoglycoprotein (38 kDa) on expression of matrix metalloproteinase-9 in 12-O-tetradecanoylphorbol-13-acetate-treated HepG2cells

Tumor metastasis is one of the main causes of death for patients with malignant tumors. Matrix metalloproteinase-9 (MMP-9) has been implicated in the invasion and metastasis of various cancer cells. Firstly, glycoprotein isolated from Styrax japonica Siebold et al. Zuccarini (SJSZ) has a molecular weight with 38 kDa and consists of carbohydrate (57.64%) and protein (42.35%). In the composition of SJSZ glycoprotein, carbohydrate mostly consists of glucose (28.17%), galactose (21.85%) and mannose (2.62%) out of 52.64%, respectively. the protein consists of Trp (W, 7.01%), Pro (P, 6.72%), and Ile (I, 5.42%) out of 42.35% as three major amino acids, while total amount of other amino acids is 23.20%. The present study was designed to demonstrate whether or not SJSZ glycoprotein prevents the activity of MMP-9 as a metastasis factor against 12-O-tetradecanoylphorbol-13-acetate (TPA). The study evaluated intracellular ROS and the phosphorylation of mitogen-activated protein kinases (MAPKs: extracellular signal-regulated kinase [ERK], stress-activated protein kinase/c-Jun N-terminal kinase [SAPK/JNK] and the p38 MAPK), the activities of transcriptional factors (nuclear factor [NF]-κB and activator protein [AP]-1), cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), and MMP-9 in TPA-induced HepG2 cells using the Western blotting analysis, EMSA and gelatin zymography. The results showed that SJSZ glycoprotein (50 μg/ml) suppressed the production of intracellular ROS and the phosphorylation of ERK, JNK and p38 MAPK, as well as the activities of transcriptional factors (NF-κB and AP-1), COX-2, iNOS, and MMP-9 in TPA-induced HepG2 cells. Taking the aforementioned results into account together, this present study suggested that SJSZ glycoprotein might be a potent anti-metastatic agent that suppresses MMP-9 enzymatic activity via the NF-κB and AP-1 signaling pathway.

Inhibitory effects of GL-V9 on the invasion of human breast carcinoma cells by downregulating the expression and activity of matrix metalloproteinase-2/9

Cancer cell invasion plays a crucial role in growth and local spreading of tumors. GL-V9 is a newly synthesized flavonoid that has been shown to possess an antitumor effect. However, the mechanism of GL-V9 in preventing tumor growth is still unclear. The purpose of this study is to investigate the anti-invasive and anti-metastatic activity of this novel compound in MDA-MB-231 and MCF-7 human breast carcinoma cells. In this study, GL-V9 caused a concentration-dependent suppression of cell adhesive ability by cell adhesion assay, it also inhibited the migration and invasion of cells by wound healing assay and transwell invasion assay in a concentration-dependent manner. Considering matrix metalloproteinases (MMPs) play an important role in metastatic process, we used western blotting and gelatin zymography to examine the effect of GL-V9 on the expression and activity of MMPs. The mechanism revealed that GL-V9 significantly suppressed the expression and activity of MMP-2 and MMP-9. Furthermore, GL-V9 suppressed their upstream protein kinases activation by reducing phosphorylated forms of serine/threonine kinase AKT and c-Jun N-terminal kinase. These findings suggested that GL-V9 could inhibit the invasion of tumor cells by downregulating the expression and activity of MMP-2 and MMP-9, potentially associating with the suppression of phosphorylation of AKT and JNK.

Inhibition of VEGF signaling pathway attenuates hemorrhage after tPA treatment

An angiogenic factor, vascular endothelial growth factor (VEGF), might be associated with the blood-brain barrier (BBB) disruption after focal cerebral ischemia; however, it remains unknown whether hemorrhagic transformation (HT) after tissue plasminogen activator (tPA) treatment is related to the activation of VEGF signaling pathway in BBB. Here, we hypothesized that inhibition of VEGF signaling pathway can attenuate HT after tPA treatment. Rats subjected to thromboembolic focal cerebral ischemia were assigned to a permanent ischemia group and groups treated with tPA at 1 or 4 hours after ischemia. Anti-VEGF neutralizing antibody or control antibody was administered simultaneously with tPA. At 24 hours after ischemia, we evaluated the effects of the antibody on the VEGF expression, matrix metalloproteinase-9 (MMP-9) activation, degradation of BBB components, and HT. Delayed tPA treatment at 4 hours after ischemia promoted expression of VEGF in BBB, MMP-9 activation, degradation of BBB components, and HT. Compared with tPA and control antibody, combination treatment with tPA and the anti-VEGF neutralizing antibody significantly attenuated VEGF expression in BBB, MMP-9 activation, degradation of BBB components, and HT. It also improved motor outcome and mortality. Inhibition of VEGF signaling pathway may be a promising therapeutic strategy for attenuating HT after tPA treatment.

Protein kinase C δ is a downstream effector of oncogenic K-ras in lung tumors

Oncogenic activation of K-ras occurs commonly in non-small cell lung cancer (NSCLC), but strategies to therapeutically target this pathway have been challenging to develop. Information about downstream effectors of K-ras remains incomplete, and tractable targets are yet to be defined. In this study, we investigated the role of protein kinase C δ (PKCδ) in K-ras-dependent lung tumorigenesis by using a mouse carcinogen model and human NSCLC cells. The incidence of urethane-induced lung tumors was decreased by 69% in PKCδ-deficient knockout (δKO) mice compared with wild-type (δWT) mice. δKO tumors are smaller and showed reduced proliferation. DNA sequencing indicated that all δWT tumors had activating mutations in KRAS, whereas only 69% of δKO tumors did, suggesting that PKCδ acts as a tumor promoter downstream of oncogenic K-ras while acting as a tumor suppressor in other oncogenic contexts. Similar results were obtained in a panel of NSCLC cell lines with oncogenic K-ras but which differ in their dependence on K-ras for survival. RNA interference-mediated attenuation of PKCδ inhibited anchorage-independent growth, invasion, migration, and tumorigenesis in K-ras-dependent cells. These effects were associated with suppression of mitogen-activated protein kinase pathway activation. In contrast, PKCδ attenuation enhanced anchorage-independent growth, invasion, and migration in NSCLC cells that were either K-ras-independent or that had WT KRAS. Unexpectedly, our studies indicate that the function of PKCδ in tumor cells depends on a specific oncogenic context, as loss of PKCδ in NSCLC cells suppressed transformed growth only in cells dependent on oncogenic K-ras for proliferation and survival.

Dihydroavenanthramide D inhibits human breast cancer cell invasion through suppression of MMP-9 expression

Dihydroavenanthramide D (DHAvD) is a synthetic analog to naturally occurring avenanthramide, which is the active component of oat. Previous study demonstrates that DHAvD strongly inhibits activation of nuclear factor-kappa B (NF-κB), which is a major component in cancer cell invasion. The present study investigated whether DHAvD can modulate MMP-9 expression and cell invasion in MCF-7 human breast cancer cells. MMP-9 expression and cell invasion in response to 12-O-tetradecanoylphorbol-13-acetate (TPA) was increased, whereas these inductions were muted by DHAvD. DHAvD also suppressed activation of mitogen-activated protein kinase (MAPK), and MAPK-mediated nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1) activations in TPA-treated MCF-7 cells. The results indicate that DHAvD-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of the MAPK/NF-κB and MAPK/AP-1 pathways in MCF-7 cells. DHAvD may have potential value in breast cancer metastasis.

Antioxidant activities of total phenols of Prunella vulgaris L. in vitro and in tumor-bearing mice

Prunella vulgaris L. (PV, Labiatae) is known as a self-heal herb. The different extracts of dried spikes were studied for the best antioxidant active compounds. The 60% ethanol extract (P-60) showed strong antioxidant activity based on the results of 2,2'-azino-di(3-ethylbenzthiazoline-6-sulfonic acid (ABTS˙+), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assay methods. High performance liquid chromatography (HPLC) and LC/MS analysis showed that the main active compounds in P-60 were phenols, such as caffeic acid, rosmarinic acid, rutin and quercetin. Total phenols were highly correlated with the antioxidant activity (R2=0.9988 in ABTS˙+; 0.6284 in DPPH and 0.9673 FRAP tests). P-60 could inhibit significantly the tumor growth in C57BL/6 mice. It can also been showed that increased superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) content in serum of tumor-bearing mice. These results suggested that P-60 extract had high antioxidant activity in vitro and in vivo and total phenols played an important role in antioxidant activity for inhibition of tumor growth.

6-Shogaol, an active constituent of ginger, inhibits breast cancer cell invasion by reducing matrix metalloproteinase-9 expression via blockade of nuclear factor-κB activation

BACKGROUND AND PURPOSE

Shogaols are reported to possess anti-inflammatory and anticancer activities. However, the antimetastatic potential of shogaols remains unexplored. This study was performed to assess the effects of shogaols against breast cancer cell invasion and to investigate the underlying mechanisms.

EXPERIMENTAL APPROACH

The anti-invasive effect of a series of shogaols was initially evaluated on MDA-MB-231 breast cancer cells using the matrigel invasion assay. The suppressive effects of 6-shogaol on phorbol 12-myristate 13-acetate (PMA)-induced matrix metalloproteinase-9 (MMP-9) gelatinolytic activity and nuclear factor-κB (NF-κB) activation were further determined.

KEY RESULTS

Shogaols (6-, 8- and 10-shogaol) inhibited PMA-stimulated MDA-MB-231 cell invasion with an accompanying decrease in MMP-9 secretion. 6-Shogaol was identified to display the greatest anti-invasive effect in association with a dose-dependent reduction in MMP-9 gene activation, protein expression and secretion. The NF-κB transcriptional activity was decreased by 6-shogaol; an effect mediated by inhibition of IκB phosphorylation and degradation that subsequently led to suppression of NF-κB p65 phosphorylation and nuclear translocation. In addition, 6-shogaol was found to inhibit JNK activation with no resulting reduction in activator protein-1 transcriptional activity. By using specific inhibitors, it was demonstrated that ERK and NF-κB signalling, but not JNK and p38 signalling, were involved in PMA-stimulated MMP-9 activation.

CONCLUSIONS AND IMPLICATIONS

6-Shogaol is a potent inhibitor of MDA-MB-231 cell invasion, and the molecular mechanism involves at least in part the down-regulation of MMP-9 transcription by targeting the NF-κB activation cascade. This class of naturally occurring small molecules thus have potential for clinical use as antimetastatic treatments.

12-O-tetradecanoylphorbol-13-acetate-induced invasion/migration of glioblastoma cells through activating PKCalpha/ERK/NF-kappaB-dependent MMP-9 expression

An increase in MMP-9 gene expression and enzyme activity with stimulating the migration of GBM8401 glioma cells via wound healing assay by 12-O-tetradecanoylphorbol-13-acetate (TPA) was detected in glioblastoma cells GBM8401. TPA-induced translocation of protein kinase C (PKC)alpha from the cytosol to membranes, and migration of GBM8401 elicited by TPA was suppressed by adding the PKCalpha inhibitors, GF109203X and H7. Activation of extracellular signal-regulated kinase (ERK) and c-Jun-N-terminal kinase (JNK) by TPA was identified, and TPA-induced migration and MMP-9 activity was significantly blocked by ERK inhibitor PD98059 and U0126, but not JNK inhibitor SP600125. Activation of NF-kappaB protein p65 nuclear translocation and IkappaBalpha protein phosphorylation with increased NF-kappaB-directed luciferase activity by TPA were observed, and these were blocked by the PD98059 and IkB inhibitor BAY117082 accompanied by reducing migration and MMP-9 activity induced by TPA in GBM8401 cells. Transfection of GBM8401 cells with PKCalpha siRNA specifically reduced PKCalpha protein expression with blocking TPA-induced MMP-9 activation and migration. Additionally, suppression of TPA-induced PKCalpha/ERK/NK-kappaB activation, migration, and MMP-9 activation by flavonoids including kaempferol (Kae; 3,5,7,4'-tetrahydroxyflavone), luteolin (Lut; 5,7,3'4'-tetrahydroxyflavone), and wogonin (Wog; 5,7-dihydroxy-8-methoxyflavone) was demonstrated, and structure-activity relationship (SAR) studies showed that hydroxyl (OH) groups at C4' and C8 are critical for flavonoids' action against MMP-9 enzyme activation and migration/invasion of glioblastoma cells elicited by TPA. Application of flavonoids to prevent the migration/invasion of glioblastoma cells through blocking PKCalpha/ERK/NF-kappaB activation is first demonstrated herein.

Suppression of Proliferation and Invasive Behavior of Human Metastatic Breast Cancer Cells by Dietary Supplement BreastDefend

Aim: The study was to evaluate the effect of the dietary supplement BreastDefend (BD) on the proliferation and invasive behavior of highly metastatic human breast cancer cells in vitro. Methods: Cell proliferation and cytotoxicity of BD was evaluated in MDA-MB-231 cells treated with BD (0-40 μg/mL) by MTT assay and trypan blue staining, respectively. Expression of cell cycle regulatory genes were determined by DNA-microarray analysis. Effect of BD on invasiveness was assessed by cellular adhesion, migration, and invasion assays. Results: BD treatment of cells MDA-MB-231 resulted in the cytostatic inhibition of cell proliferation with IC50 22.2, 19.1, and 17.5 μg/mL for 24, 48, and 72 hours, respectively. The inhibition of proliferation was mediated by the upregulation expression of CCNG1, CHEK1, CDKN1C, GADD45A, and E2F2, whereas BD downregulated expression of CCNA1 and CDK6 genes. The induction of expression of GADD45A and inhibition of expression of cyclin A1 (gene CCNA1) by BD was also confirmed on the protein level. BD treatment suppressed the invasive behavior of MDA-MB-231 cells by the inhibition of cellular adhesion, migration, and invasion. This inhibition of invasiveness was mediated by the suppression of secretion of urokinase plasminogen activator (uPA), and by the downregulation of expression of CXCR4 in breast cancer cells treated with BD. Conclusion: BD inhibits proliferation and invasive behavior of the highly metastatic human breast cancer cells in vitro. BD may have a therapeutic potential for prevention or treatment of highly metastatic breast cancers.

Serum cytokine concentrations, flavonol intake and colorectal adenoma recurrence in the Polyp Prevention Trial

Background:

Serum cytokine concentrations may reflect inflammatory processes occurring during the development of colorectal neoplasms. Flavonols, bioactive compounds found in plant-based foods and beverages, may inhibit colorectal neoplasms partly by attenuating inflammation.

Methods:

Using logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) to investigate the association between serum concentrations of interleukin (IL)1β, 2, 8, 10, 12p70, granulocyte macrophage colony stimulating factor, interferon-γ, and tumour necrosis factor-α, measured over time, flavonol intake, estimated from a flavonol database used in conjunction with a food frequency questionnaire, and adenoma recurrence in 872 participants from the intervention arm of the Polyp Prevention Trial.

Results:

Decreased IL-2 concentration during the trial increased the risk of any adenoma recurrence (4th vs 1st quartile, OR=1.68, 95% CI=1.13–2.49), whereas decreased IL-1β or IL-10 reduced the risk of advanced adenoma recurrence (OR=0.37, 95% CI=0.15–0.94; OR=0.39, 95% CI=0.15–0.98, respectively). Individuals with flavonol intake above the median (29.7 mg per day) and decreased cytokine concentrations had the lowest risk of advanced adenoma recurrence.

Conclusion:

Overall, no consistent associations were observed between serum cytokine profile and colorectal adenoma recurrence; however, decreased cytokine concentrations during high flavonol consumption may indicate prevention of colorectal neoplasms.