Pu-erh tea polysaccharides decrease blood sugar by inhibition of α-glucosidase activity in vitro and in mice.

Type 2 diabetes is mainly induced by environmental factors such as being overweight, decreased physical activity and inbalanced energy metabolism, such as pancreatic beta-cell dysfunction and peripheral insulin resistance. Acarbose, a microbial carbohydrate and an alpha-glucosidase inhibitor, is currently a useful agent for attenuating type 2 diabetes. However, it is usually accompanied by many side effects, such as abdominal distention, flatulence, diarrhea and meteorism. These side effects may be caused by its strong inhibition of alpha-amylase, leading to the accumulation of several undigested carbohydrates. The bacteria residing in the colon can further ferment the undigested carbohydrate to release gas. Finding a new alpha-glucosidase inhibitor with a low inhibitory effect on alpha-amylase is highly anticipated. In this report we describe a group of carbohydrates found in pu-erh tea polysaccharide (PTPS) that can inhibit alpha-glucosidase but have less of an inhibitory effect on alpha-amylase. The preliminary experiments on mice indicate that PTPS might be better than acarbose at suppressing blood glucose after oral administration of a carbohydrate diet; it is recommended that further clinical trials are required in type 2 diabetes in future studies.

Induction of p21(Waf1/Cip1) by garcinol via downregulation of p38-MAPK signaling in p53-independent H1299 lung cancer.

Garcinol, a polyisoprenylated benzophenone, from Garcinia indica fruit rind has possessed anti-inflammatory, antioxidant, antiproliferation, and anticancer activities. However, the anticancer mechanisms of garcinol in lung cancer were still unclear. Therefore, we examine the effects of garcinol on antiproliferation in human lung cancer cells. Treatments with garcinol for 24 h exhibited morphological changes and inhibited the proliferation of H460 (p53-wild type) and H1299 (p53-null) cells in dose- and time-dependent manners. Furthermore, a significant G1 cell cycle arrest was observed in a dose-dependent treatment after H1299 cells were exposed in garcinol, whereas garcinol induced apoptosis rather than cell cycle arrest in H460 cells. Moreover, cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 4 (CDK4), cyclin D1, and cyclin D3 were decreased, although cyclin E and cyclin-dependent kinase 6 (CDK6) were increased in garcinol-treated H1299 cells. Meanwhile, the protein levels of CDK inhibitors p21(Waf1/Cip1) and p27(KIP1) also exhibited upregulation after garcinol treatments. The enhanced protein-associated level between p21(Waf1/Cip1) and CDK4/2 rather than p27(KIP1) and CDK4/2 was demonstrated in garcinol-treated cells. Additionally, knock-down p21(Waf1/Cip1) by specific siRNA competently prevented garcinol-induced G1 arrest. Besides, garcinol also inhibited ERK and p38-MAPK activations in time-dependent mode. The pretreatment with p38-MAPK inhibitor but not ERK inhibitor raised garcinol-induced G1 population cells. Co-treatment with p38-MAPK inhibitor and garcinol synergistically elevated cyclin E, p21(Waf1/Cip1), and p27(Kip1) expressions. Meanwhile, overexpression dominant negative p38-MAPK also enhanced garcinol-induced p21(Waf1/Cip1) expression in H1299 cells. Accordingly, our data suggested that garcinol induced G1 cell cycle arrest and apoptosis in lung cancer cells under different p53 statuses. The p53-independent G1 cell cycle arrest induced by garcinol might be through upregulation of p21(Waf1/Cip1) triggered from p38-MAPK signaling inactivation.

Weight reduction effect of Puerh tea in male patients with metabolic syndrome.

Puerh tea has been proposed to promote weight loss and favorably modify glucose, insulin and blood lipids. This study tested the effect of daily Puerh tea consumption for 3 months on weight and body mass index (BMI), and select metabolic parameters. The effect of daily Puerh tea intake on weight, BMI and changes in glucose, HbA1c and lipids was evaluated in patients with metabolic syndrome. The patients (N = 70) were randomized into two groups: those taking Puerh tea extract capsule (333 mg Puerh tea extract) three times a day and those taking a placebo tea for 3 months. There was a decrease in body weight of 1.3 kg in the Puerh tea group (p = 0.077) versus 0.23 kg in the placebo arm (p = 0.186). There was also a slight decrease in BMI 0.47 kg/m(2) in the Puerh tea group (p = 0.076) versus 0.09 kg/m(2) in the placebo arm (p = 0.185), suggesting a trend of weight change, but without statistical significance. Subgroup analysis of the male patients demonstrated statistically significant improvements in body weight reduction (p = 0.004) and BMI (p = 0.004). However, the change in other metabolic parameters (cholesterol or triglyceride) or HbA1c was not statistically significant. Intake of Puerh tea for 3 months was associated with a slight reduction in body weight and BMI, especially in the male patients. Therefore, daily Puerh tea consumption may be an alternative choice to modify body weight.

Bufalin increases sensitivity to AKT/mTOR-induced autophagic cell death in SK-HEP-1 human hepatocellular carcinoma cells.

Bufalin is the major component of Chan-Su (a traditional Chinese medicine, TCM) extracts from the venom of Bufo bufo gargarizan. In the present study, we investigated the pharmacological mechanisms of cell cycle arrest and autophagic cell death induced by bufalin in SK-HEP-1 human hepatocellular carcinoma cells in vitro. Bufalin inhibited cell survival by MTT assay and increased cell death by trypan blue exclusion assay in a concentration-dependent manner. In addition, bufalin induced G2/M phase arrest by reducing CDK1 activity. Bufalin triggered DNA fragmentation and apoptotic cell death in SK-HEP-1 cells by DNA gel electrophoresis, TUNEL and caspase-3 activity assay, while bufalin induced autophagic cell death by double-membrane vacuoles (transmission electron microscopy, TEM), acidic vesicular organelles (acridine orange staining) and cleavage of microtubule-associated protein 1 light chain 3 (LC3). Protein expression levels of cyclin A and B, CDK1, phospho-CDK1 (Thr161), Cdc25c, phospho-Cdc25c (Ser198), phospho-AKT (Thr308), phospho-AKT (Ser473), phospho­mTOR (Ser2481) were downregulated. In contrast, protein expression levels of the Chk1, Wee1, LC3-II, Beclin-1, Atg 5, Atg 7 and Atg 12 were upregulated in SK-HEP-1 cells after bufalin treatment. Inhibition of autophagy by 3-methyladenine (an inhibitor of class III phosphatidylinositol-3 kinase; 3-MA) or bafilomycin A1 (an inhibitor of the vacuolar proton pump of lysosomes and endosomes) reduced the effect of bufalin on cell viability and enhanced the effect of bufalin on apoptosis. In conclusion, bufalin triggered autophagic cell death and G2/M phase arrest through the AKT/mTOR signaling pathway in SK-HEP-1 cells. Our findings showed that bufalin may be potentially efficacious in the treatment of human hepatocellular carcinoma.

Cycle arrest and apoptosis in MDA-MB-231/Her2 cells induced by curcumin.

Breast cancers with an overexpression of Her-2 or Skp2 overlap with those affected by reduced p27 expression. In breast cancer, the loss of p27 is associated with a poor prognosis. Curcumin, the main constituent of turmeric, has been found to stabilize p27 levels in breast cancer, but whether this effect is mediated through changes in Skp2 or Her2 expression remains unclear. This study investigates whether curcumin inhibits Skp2-mediated p27 ubiquitination in Her2/Skp2-overexpressing cancer cell lines (MDA-MB-231/Her2 cells). The results show that curcumin represses cell proliferation, induces G1 arrest at a lower dosage (30µM), triggers apoptosis at a higher dosage (50µM) and blocks cell migration in MDA-MB-231/Her2 cells. A low dose of curcumin increases p27 and decreases Skp2, Her2, Cyclin E, CDK kinases in a time- and dose-dependent manner, suggesting that p27, Skp2 and Her2 may be involved in the growth inhibition in MDA-MB-231/Her2 cells induced by curcumin. However, higher doses of curcumin produce a dose-dependent apoptotic death in MDA-MB-231/Her2 cells, which is related to cleaved forms of PARP and caspase 3. The findings indicate that curcumin is of potential value for the chemoprevention of breast cancer, especially in breast cancer with Skp2/Her2 overexpression.

Pu-erh tea, green tea, and black tea suppresses hyperlipidemia, hyperleptinemia and fatty acid synthase through activating AMPK in rats fed a high-fructose diet.

Although green tea extract has been reported to suppress hyperlipidemia, it is unclear how tea extracts prepared from green, oolong, black and pu-erh teas modulate fatty acid synthase expression in rats fed on a high-fructose diet. In this animal study, we evaluated the hypolipidemic and hypoleptinemia effect of these four different tea leaves fed to male Wistar rats for 12 weeks. The results showed that a fructose-rich diet significantly elevated serum triacylglycerols, cholesterol, insulin, and leptin concentrations, as compared with those in the control group. Interestingly, consuming tea leaves for 12 weeks almost normalized the serum triacylglycerols concentrations. Again, rats fed with fructose/green tea and fructose/pu-erh tea showed the greatest reduction in serum TG, cholesterol, insulin and leptin levels. In contrast, serum cholesterol and insulin concentrations of the fructose/oolong tea-fed rats did not normalize. The relative epididymal adipose tissue weight was lower in all rats supplemented with tea leaves than those fed with fructose alone. There was molecular evidence of improved lipid homeostasis according to fatty acid synthase (FAS) protein expression. Furthermore, supplementation of green, black, and pu-erh tea leaves significantly decreased hepatic FAS mRNA and protein levels, and increased AMPK phosphorylation, compared with those of rats fed with fructose only. These findings suggest that the intake of green, black, and pu-erh tea leaves ameliorated the fructose-induced hyperlipidemia and hyperleptinemia state in part through the suppression of FAS protein levels and increased AMPK phosphorylation.

Suppression of free fatty acid-induced insulin resistance by phytopolyphenols in C2C12 mouse skeletal muscle cells.

It was reported that increased plasma levels of free fatty acids (FFAs) are associated with profound insulin resistance in skeletal muscle and may also play a critical role in the insulin resistance of obesity and type 2 diabetes mellitus. Skeletal muscle is the major site for insulin-stimulated glucose uptake and is involved in energy regulation and homeostasis. In this study, we used 12-O-tetradecanoylphorbol 13-acetate (TPA), a protein kinase C (PKC) activator, and palmitate to induce insulin resistance in C2C12 mouse skeletal muscle cells. Our data show that epigallocatechin gallate (EGCG) and curcumin treatment reduce insulin receptor substrate-1 (IRS-1) Ser307 phosphorylation, and curcumin is more potent to increase Akt phosphorylation in TPA induction. Moreover, we found that after 5 h of palmitate incubation, epicatechin gallate (ECG) can suppress IRS-1 Ser307 phosphorylation and significantly promote Akt, ERK1/2, p38 MAPK, and AMP-activated protein kinase activation. With a longer incubation with palmitate, IRS-1 exhibited a dramatic depletion, and treatment with EGCG, ECG, and curcumin could reverse IRS-1 expression, Akt phosphorylation, and MAPK signaling cascade activation and improve glucose uptake in C2C12 skeletal muscle cells, especially ECG and curcumin. In addition, treatment with these polyphenols can suppress acetyl-CoA carboxylase activation, but only EGCG could inhibit lipid accumulation in the intracellular site. These findings may suggest that curcumin shows the best capacity to improve FFA-induced insulin resistance than the other two, and ECG was more effective than EGCG in attenuating insulin resistance.

EGCG inhibits the invasion of highly invasive CL1-5 lung cancer cells through suppressing MMP-2 expression via JNK signaling and induces G2/M arrest.

Tumor metastasis is the main obstacle to the treatment of lung cancer. According to previous findings, matrix metalloproteinase-2 (MMP-2) is closely correlated with metastatic potential in lung cancer. This study showed that epigallocatechin-3-gallate (EGCG), a natural polyphenol in green tea, is a potent inhibitor of MMP-2 expression. EGCG effectively suppressed the invasion and migration of highly invasive CL1-5 lung cancer cells. Gelatin zymography, Western blot analysis, and RT-PCR were used to investigate the effects of EGCG on MMP-2 expression. The effects of EGCG on cell cycle and apoptosis were determined by flow cytometry analysis. To investigate the effects of EGCG on cell migration and cell invasion, Transwell migration/invasion assays were used. EGCG downregulated MMP-2 expression at the transcriptional level in CL1-5 cells. Moreover, the treatment of CL1-5 cells with EGCG caused downregulation of c- Jun N-terminal kinase (JNK), resulting in repression of the translocation of transcriptional factors, Sp1, and NF-κB, from the cytosol into the nucleus. In addition, EGCG significantly and synergistically enhanced the antitumor effects of the clinical drug, docetaxel, in CL1-5 cells. Further, EGCG induced G2/M arrest at dosages higher than those of suppression in cell invasion in CL1-5 cells. These results reveal that EGCG might decrease MMP-2 mRNA expression through JNK signaling, further suggesting that a combination of EGCG and docetaxel may be a promising strategy to help increase the efficacy of docetaxel in suppressing metastasis in lung cancer cells. In addition, EGCG may suppress cell proliferation in CL1-5 cells through inducing G2/M arrest.

Multistage carcinogenesis process as molecular targets in cancer chemoprevention by epicatechin-3-gallate.

The consumption of green tea has long been associated with a reduced risk of cancer development. (-)-Epicatechin-3-gallate (ECG) or (-)-epigallocatechin-3-gallate (EGCG) are the major antioxidative polyphenolic compounds of green tea. They have been shown to exert growth-inhibitory potential of various cancer cells in culture and antitumor activity in vivo models. ECG or EGCG could interact with various molecules like proteins, transcription factors, and enzymes, which block multiple stages of carcinogenesis via regulating intracellular signaling transduction pathways. Moreover, ECG and EGCG possess pharmacological and physiological properties including induction of phase II enzymes, mediation of anti-inflammation response, regulation of cell proliferation and apoptosis effects and prevention of tumor angiogenesis, invasion and metastasis. Numerous review articles have been focused on EGCG, however none have been focused on ECG despite many studies supporting the cancer preventive potential of ECG. To develop ECG as an anticarcinogenic agent, more clear understanding of the cell signaling pathways and the molecular targets responsible for chemopreventive and chemotherapeutic effects are needed. This review summarizes recent research on the ECG-induced cellular signal transduction events which implicate in cancer management.

1,2,3,4,6-penta-O-galloyl-ß-D-glucose, quercetin, curcumin and lycopene induce cell-cycle arrest in MDA-MB-231 and BT474 cells through downregulation of Skp2 protein.

The F-box protein S-phase kinase-associated protein 2 (Skp2), which acts as an oncogene through targeting p27 for degradation, is overexpressed in many different human cancers. Skp2 can play an important role in breast cancer progression and may also be a novel molecular target for the treatment of breast cancer, especially estrogen receptor (ER)/human epidermal growth factor 2 (HER2) negative breast cancers. Unfortunately, specific drugs that target Skp2 are unavailable at present. Therefore, it is important to explore whether commonly used chemopreventive agents may downregulate Skp2 expression. In this study, we examined the effects of 1,2,3,4,6-penta-O-galloyl-ß-D-glucose (pentagalloylglucose, 5gg), quercetin, curcumin and lycopene on the expression of Skp2 in MDA-MB-231 (ER/HER2-negative) and BT474 (ER-negative/HER2-positive) cells. We found that all four phytochemicals studied induced cell growth inhibition in MDA-MB-231 cells. The mechanism of the initial growth inhibitory events involves blocking the cell cycle progression. Further, we found that quercetin and curcumin induced growth arrest by inhibition of Skp2, and induced p27 expression in MDA-MB-231 cells. However, the decrease in Skp2 levels in cells treated with 5gg or lycopene did not translate to p27 upregulation. Consequently, the downregulation of Skp2 did not always correlate with the upregulation of p27, suggesting that phytochemical-dependent downregulation of Skp2 can influence cell growth in several ways. Several studies have demonstrated that Skp2 directs the ubiquitylation and subsequent degradation of forkhead box protein O1 (FoxO1). Furthermore, our results reveal that FoxO1 protein was increased after 5gg, quercetin, curcumin and lycopene treatment. The therapeutic strategies designed to reduce Skp2 may therefore play an important clinical role in treatment of breast cancer cells, especially ER/HER2-negative breast cancers.

Arecoline N-oxide: its mutagenicity and possible role as ultimate carcinogen in areca oral carcinogenesis.

The areca nut is the most widely consumed psychoactive substance in Taiwan, India, and Southeast Asia. It is considered to be an environmental risk factor for the development of oral submucous fibrosis and cancer. Arecoline, the major alkaloid of areca nut, has been known to cause cytotoxicity and genotoxicity in various systems. However, the active compound accounting for arecoline-induced damage in normal human oral cells is still uncharacterized. The present study was undertaken to identify the active metabolite of arecoline that might induce damage in human oral tissues and cause mutagenicity in Salmonella typhimurium tester strains TA 100 and TA 98. It is interesting to find that the major metabolite of arecoline, arecoline N-oxide, is moderately mutagenic to these Salmonella tester strains. This mutagenicity was potently inhibited by sulfhydryl compounds, namely, glutathione, N-acetylcysteine, and cysteine, whereas methionine is inactive in this inhibition. The mutagenicity of arecoline N-oxide was strongly inhibited by the N-oxide reducing agent titanium trichloride. The possible role of arecoline N-oxide in the induction of oral carcinogenesis by areca nut chewing is discussed.

Epigallocatechin-3 gallate inhibits invasion, epithelial-mesenchymal transition, and tumor growth in oral cancer cells.

Epithelial to mesenchymal transition (EMT) is critical for the progression, invasion, and metastasis of epithelial tumorgenesis. Here, we provided molecular evidence associated with the antimetastatic effect of green tea polyphenol epigallocatechin-3 gallate (EGCG) in an oral squamous cell culture system by showing a nearly complete inhibition on the invasion (P < 0.001) of squamous cell carcinoma-9 (SCC-9) cells via a reduced expression of matrix metalloproteinase-2 (P < 0.001) and urokinasetype plasminogen activator (P < 0.001). EGCG exerted an inhibitory effect on cell migration (P < 0.001), motility (P < 0.001), spread, and adhesion (P < 0.001). We performed Western blot to find that EGCG inhibited p-focal adhesion kinase (p-FAK), p-Src, snail-1, and vimentin, indicating the anti-EMT effect of EGCG in oral squamous cell carcinoma. EGCG was also sufficient to inhibit phorbol-12-myristate-13-acetate-induced cell invasion and matrix metalloproteinase-9 expression, as evidenced by its inhibition on the tumor growth of SCC-9 cells in vivo via cancer cell xenografted nude mice mode. These results suggested that EGCG could reduce the invasion and cell growth of tumor cells, and such a characteristic may be of great value in developing a potential cancer therapy.

Garcinol promotes neurogenesis in rat cortical progenitor cells through the duration of extracellular signal-regulated kinase signaling.

Garcinol is a polyisoprenylated benzophenone derivative found in Garcinia indica fruit rind and other species. The potential antioxidative and neuroprotective effects of garcinol in rat cortical astrocyte were demonstrated in our laboratory recently. Here, the effects of garcinol on the neuritogenesis process in cultured cortical progenitor cells were investigated to understand the roles of garcinol in neuronal survival and differentiation. These cells, derived from embryonic day 17 rats, differentiated into EGF-responsive neural precursor cells, would further form neurospheres. Our data exhibited garcinol induced neurite outgrowth in early developing EGF-treated neurospheres and significantly enhanced the expression of neuronal proteins, microtubule-associated protein 2 (MAP-2), and glial fibrillary acidic protein (GFAP). Furthermore, the neuronal marker, high-molecular-weight subunit of neurofilaments (NFH), was highly expressed after 5 µM garcinol treatment in neural precursor cells for 20 days. To identify the extracellular mechanism, rat cortical progenitor cells were treated garcinol and accordingly mediated the sustained activation of extracellular signal-regulated kinase (ERK) for different periods up to 20 h. In this regard, NMDA receptor-mediated calcium influx led to excitotoxic death and activated tyrosine phosphatase which limited the duration of ERK in cultured neurons. MK801, the NMDA receptor antagonist, treatment also induced the sustained phosphorylation of ERK and therefore enhanced neuronal survival. In our observation, garcinol treatment reduced growth factor deprivation-mediated cell death and nuclear import of C/EBPß levels. Noteworthy, garcinol could promote neurite outgrowth in EGF-responsive neural precursor cells and modulate the ERK pathway in the enhancement of neuronal survival.

Chemical composition of Solanum nigrum linn extract and induction of autophagy by leaf water extract and its major flavonoids in AU565 breast cancer cells.

Solanum nigrum Linn (SN) belongs to the Solanaceae family, is a plant growing widely in south Asia, and has been used in traditional folk medicine. It is believed to have antipyretic, diuretic, anticancer, and hepatoprotective effects. During the summertime, this plant has been heavily used to supplement beverages to quench thirst on hot days in Taiwan and several southern Asian countries. In this study, the polyphenols and anthocyanidin in various parts of the SN plant were analyzed by HPLC. The leaves were found to be richer in polyphenols than stem and fruit. SN leaves contained the highest concentration of gentisic acid, luteolin, apigenin, kaempferol, and m-coumaric acid. However, the anthocyanidin existed only in the purple fruits. Additionally, the cytotoxicity of the leaf, stem, or fruit extract was evaluated against cancer cell lines and normal cells. The results showed that AU565 breast cancer cells were more sensitive to the extract. Furthermore, the results demonstrated a significant cytotoxic effect of SN leaf extract on AU565 cells that was mediated via two different mechanisms depending on the exposure concentrations. A low dose of SN leaf extract induced autophagy but not apoptosis. Higher doses (>100 microg/mL) of SN leaf extract could inhibit the level of p-Akt and cause cell death due to the induction of autophagy and apoptosis. However, these findings indicate that SN leaf extract induced cell death in breast cells via two distinct antineoplastic activities, the abilities to induce apoptosis and autophagy, therefore suggesting that it may provide a useful remedy to treat breast cancer.

Rotenone induces apoptosis in MCF-7 human breast cancer cell-mediated ROS through JNK and p38 signaling.

Rotenone is an inhibitor of the mitochondrial electron transport chain complex I, resulting in the generation of reactive oxygen species (ROS). Rotenone has been shown to display anticancer activity through the induction of apoptosis in various cancer cells. However, the underlying mechanism is still not fully understood. Here, rotenone showed a strong growth inhibitory effect against human breast cancer MCF-7 cells. DNA flow cytometric analysis, chromatin condensation, and poly (ADP-ribose) polymerase (PARP) cleavage indicated rotenone actively induced apoptosis in MCF-7 cells. The antiapoptotic protein, Bcl-2, was decreased, whereas the apoptotic protein, Bax, was increased in a time-dependent manner in rotenone-induced apoptosis. Moreover, the treatment of rotenone in MCF-7 cells caused the activation of c-jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases (MAPKs), and the inactivation of extracellular signal-regulated protein kinase 1/2 (ERK1/2). The pharmacological inhibition of JNK and p38 MAPK revealed significant protection against rotenone-induced apoptosis. Taken together, these results indicate rotenone may induce apoptosis through ROS and JNK/p38 MAPKs activation in MCF-7 cells.

Epigallocatechin gallate (EGCG) and rutin suppress the glucotoxicity through activating IRS2 and AMPK signaling in rat pancreatic beta cells.

Pancreatic beta cell failure is one critical metabolic disorder in the development of type 2 diabetes. Decreased viability and dysfunction of beta cells would accelerate the diabetic pathogenesis associated with higher mortality. In this study, the tea polyphenol EGCG (epigallocatechin gallate) and the buckwheat flavonoid Rutin were investigated to attenuate the induced glucotoxicity in beta cells. EGCG and Rutin could preserve the insulin secretory machinery and stimulate insulin receptor substrate 2 (IRS2) signaling in rat pancreatic beta cells, RIN-m5F. These findings further demonstrated the reduced glucolipotoxic effects of EGCG and Rutin through activating AMP-activated protein kinase (AMPK) signaling to inhibit the activities of lipogenic enzymes and ameliorating mitochondrial function. Consequently, the cell viability was retained after attenuating the glucotoxicity through the broad effect of EGCG and Rutin. The intrinsic protective effects of EGCG and Rutin in preserving the insulin signaling and regulating lipogenesis, manipulating cell cycling, and maintaining mitochondrial function to achieve the integrity of beta cells, which highlight the possibilities of EGCG and Rutin as novel strategies for the prevention of type 2 diabetes.

Pu-erh tea attenuates hyperlipogenesis and induces hepatoma cells growth arrest through activating AMP-activated protein kinase (AMPK) in human HepG2 cells.

In the present study, we successively extracted the pu-erh raw tea with methanol (PR-1), chloroform (PR-2), ethyl acetate (PR-3), n-butanol (PR-4), and water (PR-5). Among these extracts, PR-3 extract contained ingredients with the most effective hypolipidemic potential and was further purified by column chromatography. Moreover, chronic administration of PR-3 provoked a significant reduction in levels of serum triglyceride and low-density lipoprotein (LDL) in rats. Our study demonstrated that fraction 5 from the PR-3 extract (PR-3-5s) showed a hypolipidemic effect in human hepatoma HepG2 cells. PR-3-5s decreased the expression of fatty acid synthase (FASN) and inhibited the activity of acetyl-coenzyme A carboxylase (ACC) by stimulating AMP-activated protein kinase (AMPK) through the LKB1 pathway. Moreover, PR-3-5s blocked the progression of the cell cycle at the G1 phase by inducing p53 expression and in turn upregulating p21 expression.

Penta-O-galloyl-beta-D-glucose suppresses prostate cancer bone metastasis by transcriptionally repressing EGF-induced MMP-9 expression.

Prostate carcinoma is the most frequently diagnosed malignancy and the second leading cause of cancer-related death of men in the United States. Epidermal growth factor (EGF) generated from bone tissue contributes to prostate cancer metastasis through stimulating matrix metalloproteinase (MMP) secretions from prostate cancer cells. In this study, in vitro invasion assay was performed by incubating penta-O-galloyl-beta-D-glucose (5GG) at various concentrations with 2 x 10(4) PC-3 cells for 48 h. The anti-invasive and cytotoxic effects of 5GG were found and evaluated on the human androgen-independent prostate cancer PC-3 cell line by MTT assays and Western blot analyses. 5GG inhibited the EGF-induced cell invasiveness and MMP-9 expression in a dose- and time-dependent manner by reducing the MMP-9 transcriptional activity. To explore the mechanisms for the 5GG-mediated regulation of MMP-9, we further examined the effects of 5GG on transcription factors, including NF-kappaB, AP-1, and mitogen-activated protein kinase (MAPK) activities. The results showed that 5GG suppressed the EGF-induced NF-kappaB nuclear translocation and also abrogated the EGF-induced activation of c-jun N-terminal kinase (JNK), an upstream modulator of NF-kappaB. Moreover, we showed that 5GG reduced EGFR expression through the proteasome pathway. These results suggest that 5GG may exert at least part of its anti-invasive effect in androgen-independent prostate cancer by controlling MMP-9 expression through the suppression of the EGFR/JNK pathway. Finally, 5GG suppresses invasion and tumorigenesis in nude mice treatment with intratibia injection of PC-3 cells. These in vitro and in vivo results suggest that 5GG may be a therapeutic candidate for the treatment of advanced prostate cancer.

Ursolic acid inhibits IL-1beta or TNF-alpha-induced C6 glioma invasion through suppressing the association ZIP/p62 with PKC-zeta and downregulating the MMP-9 expression.

Ursolic acid (UA), a constant constituent of Rosmarinus officinalis extracts, is a triterpenoid compound which has been shown to have antioxidant and anticarcinogenic properties. In the present study, we found that UA was able to reduce interleukin-1 beta (IL-1beta) or tumor necrosis-alpha (TNF-alpha)-induced rat C6 glioma cell invasion, which was examined by a reconstituted basement membrane in a set of transwell chambers. However, the inhibitory effect of UA did not influence cell proliferation or cause cell cytotoxity. The results analyzed by zymography assay and Western blotting revealed that the activity and expression of matrix metalloproteinase-9 (MMP-9) was eliminated by UA in a dose-dependent manner. Because MMP-9 is the target gene of the transcription factor nuclear factor-kappaB (NF-kappaB), we further investigated the effect of UA on the activity of NF-kappaB. As expected, UA upregulated the levels of IkappaBalpha (IkappaBalpha) and attenuated the nuclear translocation of p65. Furthermore, UA suppressed the IL-1beta or TNF-alpha-induced activation of protein kinase C-zeta (PKC-zeta). Our data showed UA potently inhibited the association of ZIP/p62 and PKC-zeta. Taken together, we demonstrated that UA could efficiently inhibit the interaction of ZIP/p62 and PKC-zeta. It also further suppressed the activation of NF-kappaB and downregulation of the MMP-9 protein, which in turn contributed to its inhibitory effects on IL-1beta or TNF-alpha-induced C6 glioma cell invasion. These results all showcase the potential UA has in the chemoprevention and treatment of cancer metastasis and invasion.

Epigallocatechin gallate (EGCG) suppresses beta-amyloid-induced neurotoxicity through inhibiting c-Abl/FE65 nuclear translocation and GSK3 beta activation.

Alzheimer's disease (AD) is the most common neurodegenerative disease and is caused by an accumulation of A beta plaque deposits in the brains. Evidence is increasing that green tea flavonoids can protect cells from A beta-mediated neurotoxicity. However, the underlying mechanism remains unclear. Here, we used a human neuronal cell line MC65 conditional expression of an amyloid precursor protein fragment (APP-C99) to investigate the protection mechanism of epigallocatechin gallate (EGCG), the main constituent of green tea. We demonstrated that treatment with EGCG reduced the A beta levels by enhancing endogenous APP nonamyloidogenic proteolytic processing. Furthermore, EGCG also decreased nuclear translocation of c-Abl and blocked APP-C99-dependent GSK3 beta activation, and these inhibitory effects occurred through the interruption of c-Abl/Fe65 interaction. Our results indicated that the neuroprotective action of EGCG may take place through some mechanisms other than the promotion of APP nonamyloidogenic proteolysis, as was reported previously.