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1.
We have already reported that instant coffee powder (ICP) and ICP-loaded rat sera could suppress proliferation and invasion of rat ascites hepatoma cell line of AH109A in vitro. In this report, we examined the mechanisms for suppression of tumor cell proliferation and invasion by ICP, and the effect of ICP on in vivo tumor growth, metastasis and abnormal lipoprotein profiles in hepatoma-bearing rats. ICP, when directly added to the culture media, induced cell cycle arrest (elongation of S phase) at a lower concentration (0.3 mg/mL) and apoptosis at a higher concentration (0.6-1.2 mg/mL). ICP and ICP-loaded rat sera showed reactive oxygen species (ROS)-scavenging property and canceled the enhancement of invasive activity of hepatoma cells induced by ROS in vitro. These results suggest that ICP suppresses the proliferation by inducing cell cycle arrest and apoptosis, and the invasion by scavenging ROS and that ICP could retain these properties after their gastrointestinal absorption. The hepatoma-bearing rats were fed with a 20% casein diet (20C) or 20C supplemented with 0.1%, ICP for 14 d. Dietary ICP significantly reduced solid tumor growth and tended to reduce hepatoma metastases to lung and lymphatic nodes, suggesting that ICP could suppress tumor cell proliferation and invasion in vivo. In addition, dietary ICP significantly increased serum high-density lipoprotein (HDL)-cholesterol and tended to reduce very low-density and low-density lipoprotein (VLDL+LDL)-cholesterol, resulting in amelioration of abnormal lipoprotein profiles occurred in hepatoma-bearing rats. In conclusion, ICP has the ability to induce cell cycle arrest and apoptosis in hepatoma cells and to suppress tumor cell invasion by reducing oxidative stresses in vitro, and it could also exhibit these effects in vivo, leading to the inhibition of tumor growth and metastases.  相似文献   

2.
In this work, we compared the cancer preventive activities of Polyphenon E (PPE), a standardized green tea polyphenol preparation given in diet versus drinking fluid as well as the activities of PPE versus individual catechins. We treated Apc(Min/+) mice for 9 wk with 0.08% (-)-epigallocatechin-3-gallate (EGCG), 0.08% (-)-epicatechin-3-gallate, or 0.12% PPE in drinking fluid or diet. Only 0.12% dietary PPE and 0.08% EGCG in drinking fluid significantly decreased tumor multiplicity (70% and 51%, respectively). Compared to PPE in drinking fluid, dietary PPE delivered twofold more EGCG to the small intestine. Immunohistochemistry showed that adenomas in groups treated with PPE and EGCG had decreased cell proliferation, Beta -catenin nuclear expression, and phospho-Akt levels; higher cleaved caspase-3 levels, and partially restored retinoid X receptor alpha expression. The results suggest that these molecular events contribute to the cancer prevention activity of EGCG and PPE. Furthermore, diet appears to be a better route of administration for PPE than drinking fluid.  相似文献   

3.
Green tea and black tea (BT) contain gallated [(-)-epigallocatechin-3-gallate (EGCG), (-)-epicatechin-3-gallate] and nongallated [(-)-epicatechin, (-)-epigallocatechin (EGC)] tea polyphenols (PP). During BT production, PP undergo oxidation and form larger polymers such as theaflavins (THE) and thearubigins, which contribute to the health benefit of BT. This article gives an overview of the role of chemical characteristics and endogenous metabolism of tea PP and their bioavailability in humans and describes attempts to increase their bioavailability. At pH close to neutral, EGCG and EGC form homo- and heterodimers generating hydrogen peroxide. To confirm the pH instability of EGCG, EGC, and THE in cell culture medium, their antiproliferative activity was determined in the presence and absence of catalase. The antiproliferative activity in LNCaP prostate cancer cells was decreased when incubated with catalase prior to EGCG, EGC, and THE treatment. In addition, new findings demonstrated that the formation of methyl-EGC increased the stability at neutral pH compared with EGC. Approaches to increase the bioavailability of flavan-3-ols are reviewed, which include the administration of tea in combination with fruit juices, coadministration with piperine, and peracetylation of EGCG. Future intervention studies will need to focus on the bioactivity not only of green tea and BT PP but also of their metabolites and biotransformation products.  相似文献   

4.
In this work, we compared the cancer preventive activities of Polyphenon E (PPE), a standardized green tea polyphenol preparation given in diet versus drinking fluid as well as the activities of PPE versus individual catechins. We treated ApcMin/+ mice for 9 wk with 0.08% (-)-epigallocatechin-3-gallate (EGCG), 0.08% (-)-epicatechin-3-gallate, or 0.12% PPE in drinking fluid or diet. Only 0.12% dietary PPE and 0.08% EGCG in drinking fluid significantly decreased tumor multiplicity (70% and 51%, respectively). Compared to PPE in drinking fluid, dietary PPE delivered twofold more EGCG to the small intestine. Immunohistochemistry showed that adenomas in groups treated with PPE and EGCG had decreased cell proliferation, β -catenin nuclear expression, and phospho-Akt levels; higher cleaved caspase-3 levels, and partially restored retinoid X receptor α expression. The results suggest that these molecular events contribute to the cancer prevention activity of EGCG and PPE. Furthermore, diet appears to be a better route of administration for PPE than drinking fluid.  相似文献   

5.
Extracts of green tea and green tea polyphenols have exhibited inhibitory effects against the formation and development of tumors at different organ sites in animals. These include animal models for skin, lung, oral cavity, esophagus, stomach, intestine, colon, liver, pancreas, bladder, mammary gland, and prostate cancers. In addition to suppressing cell proliferation, promoting apoptosis, and modulating signaling transduction, green tea polyphenols, especially (-)-epigallocatechin-3-gallate, also inhibit cell invasion, angiogenesis, and metastasis. This article reviews data on the cancer preventive activities of green tea polyphenols, possible mechanisms involved, and the relationship between green tea consumption and human cancer risk.  相似文献   

6.
Extracts of green tea and green tea polyphenols have exhibited inhibitory effects against the formation and development of tumors at different organ sites in animals. These include animal models for skin, lung, oral cavity, esophagus, stomach, intestine, colon, liver, pancreas, bladder, mammary gland, and prostate cancers. In addition to suppressing cell proliferation, promoting apoptosis, and modulating signaling transduction, green tea polyphenols, especially (-)-epigallocatechin-3-gallate, also inhibit cell invasion, angiogenesis, and metastasis. This article reviews data on the cancer preventive activities of green tea polyphenols, possible mechanisms involved, and the relationship between green tea consumption and human cancer risk.  相似文献   

7.
儿茶素对LoVo细胞生长周期的影响和诱导凋亡的作用   总被引:6,自引:0,他引:6  
目的 探讨表没食子儿茶素没食子酸酯(EGCG)、表没食子儿茶素(EGC)、表儿茶素没食子酸酯(ECG)和表儿茶素(EC)对大肠癌LoVo细胞生长周期的影响和它们诱导LoVo细胞凋亡作用及其差异性。方法 用MTT法、琼脂糖凝胶电泳、透射电镜和流式细胞术观察4种儿茶素处理LoVo细胞后,它们对LoVo细胞的生长抑制作用、细胞生长周期的改变以及诱导其凋亡形态学和生化方面的改变。结果 EGCG和EGC对L  相似文献   

8.
Using the HPLC-DAD-ESI-MS/MS method, polyphenols and purine alkaloids were analyzed in young leaves of 22 tea cultivars mainly for making oolong tea in China. Ultrasonic extraction in acetonitrile–water (1:1, v/v) was chosen for the preparation of samples for HPLC analysis. Separations were performed on an ODS column with linear gradient elution by the mobile phase consisting of acetonitrile and 1% formic acid aqueous solution. Compared with the standards and data in the literature, 11 catechins, two purine alkaloids, and three non-catechin type of polyphenols were identified, including (−)-epigallocatechin-3-(3″-O-methyl) gallate, (−)-epigallocatechin-3,5-digallate, (−)-epicatechin-3-(3″-O-methyl) gallate, and (−)-epicatechin-3,5-digallate, which are not common catechins in all tea leaves. The contents of the major components, nine catechins and two purine alkaloids were quantified by the HPLC method which were fully validated. The composition of catechins in the leaves of Fujian and Taiwan cultivars group was similar, while the contents of gallated catechins were higher in Guangdong cultivars group than in Fujian and Taiwan cultivars group.  相似文献   

9.
Backgroud: (-)-Epigallocatechin-3-gallate (EGCG), the major component of green tea, is well documented to induce apoptosis and cell cycle arrest in cancer by targeting multiple signal transduction pathways. However, EGCG is extremely unstable in general culture conditions and rapidly degraded. So, to what extent EGCG or which degradation products of EGCG play a role in anti-tumor is still unknown. In this study, we evaluated the effect of different treatments of EGCG on HCT116 cells.

Design: MTT assay was applied to evaluated the inhibitory effect of different treatments of EGCG on HCT116 cells. Cell cycle and apoptosis were performed by flow cytometry. Finally, western blot analysis was used to elucidate the molecular mechanism associated with cell cycle arrest and apoptosis.

Results: Compared with control, both EGCG and O-EGCG (i.e., EGCG being pre-incubated at 37°C for 3 h) significantly inhibited HCT116 cells growth. Surprisingly, we found that the inhibitory effect of O-EGCG was stronger than that of EGCG. The IC50 values of EGCG and O-EGCG were 8.75 and 5.40 μM, respectively. Cell cycle analysis showed that 20 μM of EGCG simultaneously caused cell cycle arrest at G1 and G2 phase in HCT116 cells, differing from O-EGCG which exclusively caused cell cycle arrest at G2. This result suggested that parent EGCG at the early treatment might cause cell cycle arrest at G1. As time went on, EGCG disappeared and degraded products of EGCG were formed which might cause cell cycle arrest at G2. Further studies revealed that EGCG induced cell cycle arrest at G1 by downregulation of cyclin E and cyclin D1 and upregulation of p21. On the other hand, O-EGCG induced HCT116 cells apoptosis mainly by increasing the expression of p53 and cleaved caspase-3, which might be the underlying reason why O-EGCG had stronger inhibitory effect on HCT116 cells line than EGCG.

Conclusions: The pretreatment of EGCG may be an effective way to enhance its antitumor effect.  相似文献   

10.
Both epidemiological and experimental evidence is accumulating to show that a lignan-rich diet may reduce the risk of human breast cancer. Possible anti-cancer effects of dietary lignans on hepatomas or hepatoma cells have not been the topic of earlier studies. In the present study, we examined the effect of 7-hydroxymatairesinol (HMR) and its mammalian metabolite, enterolactone (ENL), on AH109A hepatoma cell proliferation and invasion in vitro. HMR and ENL inhibited the proliferation and invasion of AH109A hepatoma cells in vitro. The 50% inhibitory concentration (IC50) of hepatoma cell proliferation was lower for ENL (10 microM) than HMR (> 200 microM). Likewise, IC50 of hepatoma cell invasion was lower for ENL (9 microM) than HMR (144 microM). ENL suppressed hepatoma cell proliferation by accumulating cells in G1 phase and elongating doubling time of these cells, and by increasing the rate of apoptosis. Subsequently, we investigated in vivo the effect of dietary HMR and ENL on growth and metastasis of AH109A hepatomas in rats. Both of these compounds reduced the growth and metastasis of solid AH109A hepatomas in rats. These in vitro and in vivo findings suggest that HMR has inhibitory activities on tumor growth and metastasis in the hepatoma-bearing rats, and that this anti-tumor effect is mediated at least partially by ENL, a metabolite of HMR.  相似文献   

11.
The present study evaluates for the first time in dogs, the kinetics of green tea catechins and their metabolic forms in plasma and urine. Ten beagles were administered 173 mg (12.35 mg/kg body weight) of catechins as a green tea extract, in capsules. Blood samples were collected during 24 h after intake and urine samples were collected during the following periods of time: 0-2, 2-6, 6-8 and 8-24 h. Two catechins with a galloyl moiety and three conjugated metabolites were detected in plasma. Most of the detected forms in plasma reached their maximum plasma concentration (Cmax) at around 1 h. Median Cmax for ( - )-epigallocatechin-3-gallate (EGCG), ( - )-epicatechin-3-gallate (ECG), ( - )-epigallocatechin glucuronide (EGC-glucuronide), ( - )-epicatechin glucuronide (EC-glucuronide), ( - )-epicatechin sulphate (EC-sulphate) were 0.3 (range 0.1-1.9), 0.1 (range 0-0.4), 0.8 (range 0.2-3.9), 0.2 (range 0.1-1.7) and 1 (range 0.3-3.4) micromol/l, respectively. The areas under the plasma concentration v. time curves (AUC0 --> 24) were 427 (range 102-1185) micromol/l x min for EGC-glucuronide, 112 (range 53-919) micromol/l x min for EC-sulphate, 71 (range 26-306) micromol/l x min for EGCG, 40 (range 12-258) micromol/l x min for EC-glucuronide and 14 (range 0.1-124) micromol/l x min for ECG. The values of mean residence time (MRT0 --> 24) were 5 (range 2-16), 2 (range 1-11), 10 (range 2-13), 3 (range 2-16) and 2.4 (range 1-18) h for EGCG, ECG, EGC-glucuronide, EC-glucuronide and EC-sulphate, respectively. In urine, catechins were present as conjugated forms, suggesting bile excretion of EGCG and ECG. Green tea catechins are absorbed following an oral administration and EGC-glucuronide is the metabolic form that remains in the organism for a longer period of time, suggesting that this compound could suffer an enterohepatic cycle.  相似文献   

12.
Both epidemiological and experimental evidence is accumulating to show that a lignan-rich diet may reduce the risk of human breast cancer. Possible anti-cancer effects of dietary lignans on hepatomas or hepatoma cells have not been the topic of earlier studies. In the present study, we examined the effect of 7-hydroxymatairesinol (HMR) and its mammalian metabolite, enterolactone (ENL), on AH109A hepatoma cell proliferation and invasion in vitro. HMR and ENL inhibited the proliferation and invasion of AH109A hepatoma cells in vitro. The 50% inhibitory concentration (IC 50 ) of hepatoma cell proliferation was lower for ENL (10 μ M) than HMR (> 200 μ M). Likewise, IC 50 of hepatoma cell invasion was lower for ENL (9 μ M) than HMR (144 μ M). ENL suppressed hepatoma cell proliferation by accumulating cells in G 1 phase and elongating doubling time of these cells, and by increasing the rate of apoptosis. Subsequently, we investigated in vivo the effect of dietary HMR and ENL on growth and metastasis of AH109A hepatomas in rats. Both of these compounds reduced the growth and metastasis of solid AH109A hepatomas in rats. These in vitro and in vivo findings suggest that HMR has inhibitory activities on tumor growth and metastasis in the hepatoma-bearing rats, and that this anti-tumor effect is mediated at least partially by ENL, a metabolite of HMR.  相似文献   

13.
目的 利用大鼠肝癌前病变模型探讨茶多酚和茶色素对细胞周期因子的影响。方法 采用改良的Solt-Farber大鼠肝癌癌前病变模型,分别饮用0.1%和0.1%茶多酚,喂养56d。采用Westernblot方法观察细胞周期素D1、D21^WAF1/CIPI、GADD45和PCNA蛋白的表达;用RT-PCR在mRNA水平观察Ckd4的表达。结果 茶多酚和茶色素显著抑制细胞周期素D1、Ckd4和PCNA表达,诱导P21^WAF1/CIP1和GAD45蛋白表达。结论 茶多酚和茶色素通过调节细胞周期调节因子而诱导细胞周期阻滞,抑制细胞过度增值。  相似文献   

14.
15.
Esophageal squamous cell carcinoma (ESCC) is prevalent in Yanting (YT) country located in southwestern China. Residents in the YT region have an unusual diet pattern and the role of the YT diet on the risk of ESCC is still uncertain. The present study was to examine the possible effects of sera from rats fed with the YT diet on proliferation of human esophageal cancer cell line Eca-109 by means of a sero-physiology approach. Firstly, two feasibilities were assessed to set up the sero-physiology method. We found that rats fed with a human adult diet in Chengdu region (ESCC-low-risk-area) for 30d had very close body weight gains in comparison with the control rats fed with the conventional diet, confirming the feasibility of feeding rats with a human diet without affecting their normal growth. Cell growth results showed that 5% non-deactivated rat serum had exactly the same effect on the proliferation of Eca-109 cells compared with the fetal bovine sera (FBS) control, confirming the feasibility of cultivating Eca-109 cells with the rat serum instead of FBS. Subsequently, cell proliferation results indicated that rats’ sera fed with the YT diet significantly promoted Eca-109 cells proliferation but inhibited human normal liver epithelial cell line control HL7702 proliferation, whereas rats’ sera fed with the Chengdu diet didn't have these effects on the two cell lines. The different effects of the two human diets on proliferation of Eca-109 cells demonstrated that the sero-physiology method is effective in studying the relationship between diet and cancer, and there maybe exist cancer-promoting factors in the YT diet.  相似文献   

16.
目的 研究维生素D受体(VDR)异常表达对大鼠肾小管上皮细胞增殖凋亡的影响。方法 制取大鼠肾小管上皮细胞,并构建VDR干扰和过表达载体。将VDR干扰和过表达载体分别转染到大鼠肾小管上皮细胞中,通过MTT法检测VDR干扰和过表达后大鼠肾小管上皮细胞的增殖;流式细胞术检测细胞周期;Annexin - PI法检测细胞凋亡情况。结果 与对照组相比,过表达VDR后,大鼠肾小管上皮细胞的VDR蛋白表达显著上调,增殖速度下降,发生G1期阻滞,凋亡比例增多,差异具有统计学意义。而干扰VDR表达后,结果与上述相反,即大鼠肾小管上皮细胞的VDR蛋白表达显著下调,增殖速度加快,细胞凋亡比例降低,差异具有统计学意义。结论 VDR能促进大鼠肾小管上皮细胞发生细胞周期G1期阻滞,抑制细胞增殖,促进细胞凋亡。  相似文献   

17.
Oral administration of tea (Camellia sinensis) has been shown to inhibit the formation and growth of several tumor types in animal models. The present study investigated the effects of treatment with different concentrations of green tea on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in female A/J mice. Two days after a single dose of NNK (100 mg/kg body weight, i.p.), the mice were given 0.1, 0.2, 0.4, and 0.6% green tea solution (1, 2, 4, and 6 g of tea solids, respectively, dissolved in 1 l of water), 0.02% caffeine, or water as the sole source of drinking fluid until the termination of the experiment. Only the treatment with 0.6% tea preparation significantly reduced lung tumor multiplicity (mean +/- SE, 6.07 +/- 0.77 vs. 8.60 +/- 0.50 tumors per mouse, P = 0.018). Treatment with 0.6% tea also inhibited angiogenesis, as indicated by the lower microvessel density (number of blood vessels/mm2) based on immunostaining for the von Willebrand factor antigen (81.9 +/- 9.5 vs. 129.4 +/- 8.2, P = 0.0018) and anti-CD31 antibody staining (465.3 +/- 61.4 vs. 657.1 +/- 43.6, P = 0.0012). Significantly lower vascular endothelial growth factor immunostaining scores were also observed in the 0.6% tea-treated group (0.98 +/- 0.17 vs. 1.43 +/- 0.07, P = 0.006). The apoptosis index was significantly higher in lung adenomas from 0.6% tea-treated mice based on morphological analysis of cell apoptosis (2.51 +/- 0.18% vs. 1.57 +/- 0.11%, P = 0.00005), and the result was further confirmed using the TUNEL method. Inhibition of angiogenesis and the induction of apoptosis by green tea may be closely related to the inhibition of pulmonary carcinogenesis.  相似文献   

18.
新疆天然植物黑加仑对食管癌细胞增殖、凋亡的影响   总被引:2,自引:0,他引:2  
目的:观察新疆天然植物黑加仑水提物对食管癌细胞的影响及其作用机制。方法:采用四甲基偶氮唑蓝(MTT)法测定不同浓度(10-1、10-2、10-3g/ml)黑加仑水提物作用不同时间(12、24、36h)对人食管癌细胞株Eca109的细胞存活量的影响,以大鼠正常肝细胞(BRL)为正常对照细胞株;用Bradford法测定肿瘤细胞蛋白质合成的变化;采用流式细胞技术(FCM)观察黑加仑作用后肿瘤细胞周期变化及凋亡情况;通过倒置显微镜观察细胞的形态变化。结果:黑加仑水提物10-1g/ml组对人食管癌细胞株Eca109作用24h后,癌细胞的生长和蛋白合成均有明显抑制作用(P<0.05),对正常肝细胞的存活量及蛋白合成均无影响;流式细胞仪检测二倍体峰前出现凋亡峰,细胞凋亡率为49.6%;并且癌细胞呈现典型的凋亡细胞形态。结论:黑加仑水提物可通过诱导细胞凋亡而抑制人食管癌细胞株Eca109细胞的生长。  相似文献   

19.
Among black tea polyphenols, theaflavins were generally considered to be the most effective in cancer chemoprevention. In this study, we examined the inhibitory effects of black tea polyphenols, including theaflavin (TF-1), a mixture (TF-2) of theaflavin-3-gallate and theaflavin-3'-gallate, theaflavin-3,3'-digallate (TF-3), and the green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced edema and ornithine decarboxylase (ODC) activity. Topical application of these polyphenols onto the mouse resulted in inhibition of TPA-induced ear edema and skin epidermal ODC activity. The inhibitory order was as follows: TF-3 > TF-2 approximately equal to EGCG > TF-1. Western and Northern blots indicated that TF-3 significantly reduced the protein and mRNA levels of ODC in TPA-treated mouse skin and NIH 3T3 cells, whereas EGCG showed less activity. EGCG and TF-3 were able to inhibit the ODC enzyme activity in vitro. Furthermore, TF-3 also significantly reduced the basal promoter activity of the ODC gene in NIH 3T3 cells that were transiently transfected with ODC reporter plasmid. These results suggested that TF-3 was a potential inhibitor of ODC activity and TPA-induced edema and might be effective in cancer chemoprevention.  相似文献   

20.
Studies suggest that pomegranates contain bioactive chemicals with potential for treatment and prevention of cancer. Pomegranate juice extracts (PJE) have been shown to inhibit cellular proliferation and tumor growth and induce cell death via apoptosis in a number of cancer cell lines. However, to date, few studies have investigated the potential of PJE in the treatment of leukemia. We investigated the potential effect of PJE on induction of apoptosis and inhibition of cellular proliferation in 8 leukemia cell lines (4 lymphoid and 4 myeloid) and nontumor hematopoietic stem cells (control cells). Apoptosis was assessed by 2 methods: Annexin V-FITC/propidium iodide staining with flow cytometric analysis and 4'-6-diamidino-2-phenylindole (DAPI) morphological assessment. Cell cycle stage was investigated using propidum iodide staining of DNA content and flow cytometric analysis. Live cell counts were also performed using a trypan exclusion assay. PJE significantly induced apoptosis in all cell lines, including nontumor control cells, although lymphoid cells and 2 of the myeloid cell lines were more sensitive. Furthermore, PJE induced cell cycle arrest. These results were confirmed by DAPI analysis and viable cell counts using trypan blue exclusion assay. Our results provide evidence that PJE contain bioactive compounds that could be used in the treatment of leukemia.  相似文献   

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