硒酸化乳清分离蛋白抗前列腺癌细胞活性

采用干燥加热法制备硒酸化乳清分离蛋白(selenized whey protein isolate,Se-WPI),通过Se-WPI中有机硒质量分数、硒酸根稳定性、Se-WPI消化率测定,⁷⁷Se核磁共振(nuclear magnetic resonance,NMR)分析以及Se-WPI抑制前列腺癌细胞增殖实验等,研究其理化性质及抗前列腺癌细胞活性。结果表明,在pH 3.0、加热温度80℃、加热时间24 h条件下制备得到的Se-WPI中有机硒质量分数为2.09%。⁷⁷Se-NMR和硒酸根稳定性分析结果表明,Se-WPI中的硒以亚硒酸酯的形式存在。经硒酸化的WPI多种生物活性得到改善,消化性明显提高。Se-WPI与亚硒酸钠均具有抑制人前列腺癌LNCaP细胞、DU145细胞增殖的活性。细胞周期、细胞凋亡和Caspase-3活力检测结果从不同角度验证了Se-WPI具有诱导LNCaP细胞凋亡的作用。另外,Se-WPI还能抑制癌细胞与基底膜成分的黏附能力。实验结果可为进一步研究有机硒化合物的抑癌机制提供依据。     

生物凝集素分类与纯化的研究进展

凝集素是一类具有糖专一性,可促使细胞凝集的糖蛋白。凝集素已广泛应用于化学、生物化学、生物学、免疫学及医学等各个领域。本文主要对生物凝集素的分类与纯化方法进行了较为系统的阐述,为凝集素资源的开发提供一定的参考和借鉴。     

鲟鱼硫酸软骨素对结直肠癌细胞抑制作用

探究鲟鱼硫酸软骨素对结直肠癌细胞的生长抑制能力,并初步确定影响结直肠癌细胞生长的主要原因。选取3株具有代表性的结直肠癌细胞Caco-2、HCT-116、SW480,采用CCK-8法测定细胞生长曲线、硫酸软骨素对癌细胞增殖的抑制能力;以其中一株结直肠癌细胞HCT-116为模型,用流式细胞仪测定其周期和凋亡情况,用细胞核染色法观察处理前后细胞形态,结合caspase-3凋亡酶活力的测定,考察鲟鱼硫酸软骨素对结直肠癌细胞的促凋亡能力,并初步确定作用途径。研究结果表明,鲟鱼硫酸软骨素对结直肠癌细胞Caco-2、HCT-116、SW480的增殖具有一定抑制作用,最高抑制率分别为70.94%、90.00%和75.00%,明显高于阳性对照处理组;处理后,细胞周期G1/G0期比例升高至88.56%,S期比例降低至4.47%,阻滞细胞G1/G0期;同时,使用鲟鱼硫酸软骨素处理细胞后,细胞形态发生变化,出现细胞核固缩以及细胞破碎等现象,细胞主要的凋亡酶活力显著升高,酶活力可达1 645 IU/μg,使细胞发生凋亡,凋亡率可达63.73%。研究结果证明,鲟鱼硫酸软骨素具有促进结直肠癌细胞凋亡、抑制细胞增殖的能力。     

Effect of the ingestion of an extract from Bauhinia monandra seeds on rats

Bauhinia monandra is a leguminous plant that would be used in human nutrition, however it shows a high hemagglutinating activity against trypsin-treated erythrocytes of rabbit, 2 ml of a NaCl-solution extract of the seeds was given to a group of rats for 10 days. Intestinal disaccharidase activity was determined. Histopathological and histochemical examinations were also performed. Lectins from Bauhinia monandra seeds did not cause any visible intestinal damage even when they seem to be able to bind to the enterocyte brush border. The low disaccharidase activity in the membrane and enterocyte fractions, which represent the enzyme synthesis level, indicates that lectins could reduce the synthesis of these enzymes rather than inhibit the active sites of the enzymes. This effect could be in turn related with the binding action of lectins, because no effect of the autoclaved extract on the disaccharidase activity was observed.     

菌类凝集素免疫调节作用的研究进展

凝集素是一类与糖特异性结合、具有凝集细胞作用的蛋白质或糖蛋白，凝集素是菌类的重要活性成分，菌类凝集素对免疫细胞激活作用与免疫系统的调节作用，参与了菌类分化成熟与识别异源物质等多种生理过程，与菌类的抗菌作用密切相关。菌类凝集素免疫调节蛋白结构上具有与免疫球蛋白重链可变区的相似性，功能上又具有抑制过敏反应、刺激淋巴细胞增殖、促进淋巴细胞产生细胞因子、增强机体的免疫力等作用。本文介绍菌类凝集素对免疫细胞激活作用与免疫系统的调节活性，凝集素对免疫细胞表面受体的研究、凝集素对MAPK信号转导途径的研究最新研究进展进行了综述，并且对其今后的发展趋势进行了展望。为今后开展菌类凝集素活性的研究及应用开发提供参考。     

Bovine lactoferricin B induces apoptosis of human gastric cancer cell line AGS by inhibition of autophagy at a late stage

Gastric cancer is one of the most common malignant cancers, with poor prognosis and high mortality rates worldwide. Therefore, development of an effective therapeutic method without side effects is an urgent need. It has been reported that cationic antimicrobial peptides can selectively bind to negatively charged prokaryotic and cancer cell membranes and exert cytotoxicity without causing severe drug resistance. In the current study, we prepared a series of peptide fragments derived from bovine lactoferrin and evaluated their anticancer potency toward the gastric cancer cell line AGS. Cell viability assay revealed that a 25-AA peptide fragment, lactoferricin B25 (LFcinB25), exhibited the most potent anticancer capability against AGS cells. Lactoferricin B25 selectively inhibited AGS cell growth in a dose-dependent manner, exhibiting a half-maximal inhibitory concentration (IC₅₀) value of 64 μM. Flow cytometry showed a notable increment of the sub-G₁ populations of the cell cycle, indicating the induction of apoptosis by LFcinB25. Western blot analysis further revealed that upon LFcinB25 treatment for 2 to 6 h, apoptosis-related caspases-3, 7, 8, 9, and poly(ADP-ribose) polymerase (PARP) were cleaved and activated, whereas autophagy-related LC3-II and beclin-1 were concomitantly increased. Thus, both apoptosis and autophagy are involved in the early stage of LFcinB25-induced cell death of AGS cells. However, upon treatment with LFcinB25 for 12 to 24 h, LC3-II began to decrease, whereas cleaved beclin-1 increased in a time-dependent manner, suggesting that consecutive activation of caspases cleaved beclin-1 to inhibit autophagy, thus enhancing apoptosis at the final stage. These findings provide support for future application of LFcinB25 as a potential therapeutic agent for gastric cancer.     

Red mold dioscorea‐induced G2/M arrest and apoptosis in human oral cancer cells

BACKGROUND: Monascus‐fermented products are among the most commonly used traditional food supplements. Dioscorea is known to exhibit anticancer properties. In this study the effects of the ethanol extract of red mold dioscorea (RMDE) on cell proliferation, cell cycle and apoptosis in human oral cancer cells were investigated. RESULTS: RMDE exercised growth inhibition on squamous cell carcinoma‐25 (SCC‐25) cells. RMDE‐mediated G2/M phase arrest was associated with the down‐regulation of NF‐κB, resulting in the inhibition of cyclin B1 and CDK1 expression; this may be the mechanism by which RMDE inhibits cancer cells. Furthermore, the proapoptotic activity of RMDE was revealed by the Annexin V‐FITC/PI double‐staining assay. In addition, the proapoptotic effect of RMDE was evident by the inhibition of Bax expression in the mitochondria, resulting in the activation of caspase‐9 and caspase‐3 and subsequent triggering of the mitochondrial apoptotic pathway. RMDE also enhanced caspase‐8 activity, indicating the involvement of the death receptor pathway in RMDE‐mediated SCC‐25 cell apoptosis. CONCLUSION: RMDE treatment inhibited the growth of SCC‐25 cells by arresting cell cycle at the G2/M phase and induced apoptosis in a time‐ and dose‐dependent manner. Therefore RMDE may be a good candidate for development as a dietary supplement against oral cancer. Copyright © 2010 Society of Chemical Industry     

Ursolic acid,a potential anticancer compound for breast cancer therapy

There are growing interests in the health benefits associated with consumption of fruits and vegetables, especially for the prevention of cancer, cardiovascular, or other chronic diseases. Epidemiological studies and clinical trials suggest that these health benefits are strongly associated with phytochemicals found in fruits and vegetables. Ursolic acid is a naturally synthesized pentacyclic triterpenoid, widely distributed in different fruits and vegetables. Current research suggested that ursolic acid and its derivatives exhibited anticancer activity, anti-inflammatory effects, and induction of apoptosis in several human cancer cells. In particular, ursolic acid inhibited breast cancer proliferation by inducing cell G1/G2 arrest and regulating the expression of key proteins in signal transduction pathways. In addition, ursolic acid induced apoptosis in human breast cancer cells through intrinsic and extrinsic apoptotic pathways. Ursolic acid was also determined to scavenge free radicals and have potent anti-inflammation activity. The purpose of this paper is to review recent literature on anticancer activity of ursolic acid and focus on its mechanisms of action.     

Differential effects of resveratrol and its naturally occurring methylether analogs on cell cycle and apoptosis in human androgen‐responsive LNCaP cancer cells

Stilbenes are phytoalexins that become activated when plants are stressed. These compounds exist in foods and are widely consumed. Resveratrol is a grape‐derived stilbene, which possesses a wide range of health‐promoting activities, including anticancer properties. Several other stilbenes structurally similar to resveratrol are also available in food, but their biological activities remain largely unknown. In this study, we compared the effects of resveratrol and its natural derivatives pterostilbene, trans‐resveratrol trimethylether, trans‐pinostilbene and trans‐desoxyrhapontigenin on androgen‐responsive human prostate cancer LNCaP cells. We found that these compounds exert differential effects on LNCaP cell growth, cell cycle and apoptosis. Trans‐resveratrol trimethylether appeared to be the most potent compound among the stilbenes tested. Treatment of LNCaP cells with trans‐resveratrol trimethylether resulted in G2/M blockage while other compounds, including resveratrol, induced G1/S arrest. Moreover, different from other compounds, trans‐resveratrol trimethylether induced apoptosis. At the molecular level, the effects of these compounds on cell cycle correlated with induction of the cyclin‐dependent kinase inhibitor 1A and B mRNA levels. Additionally, these compounds also inhibited both androgen‐ as well as estrogen‐mediated pathways. These results provide mechanistic information on how resveratrol and its methylether analogs may act to contribute to potential antiprostate cancer activity.     

茶叶儿茶素的癌症化学预防增效机制研究进展

研究证实,茶叶中儿茶素对预防癌症起到重要的作用,其中表没食子儿茶素没食子酸酯(EGCG)具有比较强的抗氧化、抑制癌细胞增殖和诱导细胞的凋亡能力,是化学预防癌症最具潜力的天然产物之一.作者归纳了儿茶素的生物活性、EGCG与天然抗癌产物和临床药物的增效机制研究进展,为更加深入地开展EGCG癌症化学预防机制研究提供参考.     

Soy isoflavone genistein induces cell death in breast cancer cells through mobilization of endogenous copper ions and generation of reactive oxygen species

Scope: Worldwide geographical variation in cancer incidence indicates a correlation between dietary habits and cancer risk. Epidemiological studies have suggested that populations with high isoflavone intake through soy consumption have lower rates of breast, prostate, and colon cancer. Isoflavone genistein in soybean is considered a potent chemopreventive agent against cancer. Although several mechanisms have been proposed, a clear anticancer action mechanism of genistein is still not known. Methods and results: Here, we show that the cytotoxic action of genistein against breast cancer cells involves mobilization of endogenous copper. Further, whereas the copper specific chelator neocuproine is able to inhibit the apoptotic potential of genistein, the molecules which specifically bind iron (desferroxamine mesylate) and zinc (histidine) are relatively ineffective in causing such inhibition. Also, genistein‐induced apoptosis in these cells is inhibited by scavengers of reactive oxygen species (ROS) implicating ROS as effector elements leading to cell death. Conclusions: As copper levels are known to be considerably elevated in almost all types of cancers, in this proof‐of‐concept study we show that genistein is able to target endogenous copper leading to prooxidant signaling and consequent cell death. We believe that such a mechanism explains the anticancer effect of genistein as also its preferential cytotoxicity towards cancer cells.     

Anti‐inflammatory and anticancer activities of water‐soluble peptide extracts of buffalo and cow milk Cheddar cheeses

This article aimed to assess the anti‐inflammatory and anticancer potential of water‐soluble peptide (WSP) extracts from buffalo and cow milk Cheddar cheeses. Anti‐inflammatory activity was evaluated on the basis of nitric oxide (NO) production in lipopolysaccharide‐stimulated macrophage (RAW‐264.7) cells. A cell viability assay, cell cycle arrest and apoptosis were performed to explore anticancer activity in a colon cancer model (HT‐29). The WSP extracts of both Cheddar cheeses effectively inhibited NO production in activated macrophages. Maximum growth inhibition was observed in the HT‐29 cells at concentrations of 400 and 500 μg/mL. A significant increase in cell population at G₀/G₁ phase of the cell cycle was observed. Moreover, the WSP extracts also induced extensive apoptosis in colon cancer cells.     

New mechanisms and therapeutic potential of curcumin for colorectal cancer

Curcumin is a polyphenol derived from Curcuma longa. Over the last few years, a number of studies have provided evidence of its main pharmacological properties including chemosensitizing, radiosensitizing, wound healing activities, antimicrobial, antiviral, antifungical, immunomodulatory, antioxidant and anti-inflammatory. More recent data provide interesting insights into the effect of this compound on cancer chemoprevention and chemotherapy. In fact, preclinical studies have shown its ability to inhibit carcinogenesis in various types of cancer including colorectal cancer (CRC). Curcumin has the capacity of interact with multiple molecular targets affecting the multistep process of carcinogenesis. Also, curcumin is able to arrest the cell cycle, to inhibit the inflammatory response and the oxidative stress and to induce apoptosis in cancer cells. Likewise, it has been shown to possess marked antiangiogenic properties. Furthermore, curcumin potentiates the growth inhibitory effect of cyclo-oxygenase (COX)-2 inhibitors and traditional chemotherapy agents implicating another promising therapy regimen in the future treatment of CRC. However, its clinical advance has been hindered by its short biological half-life and low bioavailability after oral administration. This review is intended to provide the reader an update of the bioavailability and pharmacokinetics of curcumin and describes the recently identified molecular pathways responsible of its anticancer potential in CRC.     

Antioxidant and apoptotic potential of protein isolates derived from Vigna unguiculata (L.) Walp

Projected mortalities from cancer are expected to continue escalating, with conventional chemotherapeutic regimens having extensive side effects, hence the need for therapeutics capable of terminating cancer cells selectively, through apoptosis. Therapeutic protein isolates bind specifically to target proteins inducing cell death in vitro and in vivo in various cancer cells. Therefore, this study aimed at observing the antioxidant and anticancer potential of protein isolates from five cowpea cultivars (Glenda, Embu buff, Makhatini, Veg Cowpea 2 and Veg Cowpea 3). Cytotoxicity was conducted on cancerous and non-cancerous cell lines. Apoptosis was quantified using flow cytometry, and caspase-3/7 activity was determined. Cytotoxicity assays revealed that Embu buff was the pre-eminent inhibitor of cancerous cells, while also acting as a protecting mediator in a stressed non-cancerous cell line by causing a reversal in apoptotic activity. Therefore, cowpea isolates show high potential as candidates for the therapeutic intrusion of cancer.     

The citrus flavonoid nobiletin inhibits proliferation and induces apoptosis in human pancreatic cancer cells in vitro

The cellular effects of nobiletin on human pancreatic cancer cells (PANC-1) and the mechanisms by which nobiletin inhibits the proliferation of these cells were investigated. A MTT assay and flow cytometry were used to examine cell proliferation and apoptosis, respectively. A Western blot assay was used to examine expression levels of the apoptotic proteins bax, bcl-2, and p53. NOB induced apoptosis in these cells via up-regulation of the proapoptotic protein bax and down-regulation of the antiapoptotic proteins bcl-2 and p53. The normal cell cycle of PANC-1 cells was arrested by NOB with a significant increase in the proportion of G0/G1 phase cells (p<0.05) and a significant decrease in the proportion of S phase cells (p<0.05). NOB can inhibit the proliferation of human pancreatic carcinoma cells by inducing apoptosis and arresting the cell cycle progression.     

Anticancer effect of lipids partially purified from Pacific oyster, Crassostrea gigas on PC3 cells

The objective of this study was to determine the anticancer effects of the Pacific oyster (Crassostrea gigas) in vitro. For this study, the lipid extracts of C. gigas were prepared using several organic solvents: methanol, chloroform, hexane, methanol:chloroform=1:1, chloroform: hexane=1:1. The anticancer activity of the extracts was evaluated using cell cycle and apoptosis assays analyzed by a flow cytometry. Of all the extracts, the hexane extracts exhibited the highest anticancer activity compared to the other extracts. The hexane extracts were further separated and purified using thin layer chromatography. The final isolated lipid compounds were identified their components as palmitic acid, margaric acid, and stearic acid. These results indicate that this combination of lipids effectively inhibit in vitro human prostate tumor growth by inducing apoptosis of cancer cells.     

细香葱提取物对人胃癌细胞SGC7901抑制作用

通过四甲基偶氮唑蓝比色法和流式细胞术研究不同细香葱提取物对人胃癌细胞SGC7901增殖的抑制作用及其对细胞周期、凋亡率的影响。结果显示,细香葱抗胃癌活性成分主要集中在75%乙醇提取部位,同一区域不同品种细香葱抑制胃癌细胞增殖作用存在显著性差异(P0.05),其中3号细香葱75%乙醇提取物的抑制作用最强,其24、48、72 h时IC50值分别为(0.88±0.07)、(0.45±0.08)、(0.21±0.03)mg/m L;SGC7901细胞经1.0、2.0 mg/m L的细香葱75%乙醇提取物处理48 h后,S期细胞所占比例显著增多(P0.05),细香葱75%乙醇提取物阻碍人胃癌细胞SGC7901由S期向G2期的转化,将细胞周期阻滞于S期;同时,实验组细胞相比对照组凋亡率显著上升(P0.05),存在量效关系。综上,细香葱75%乙醇提取物能够阻滞人胃癌细胞SGC7901由S期向G2期转化、促进其凋亡并抑制细胞增殖,细香葱具有开发成为抗胃癌功能食品的潜力。     

食用色素藻蓝蛋白对非小细胞肺癌A549细胞体外增殖和凋亡的影响

本研究以人类非小细胞肺癌A549细胞系为模型,采用藻蓝蛋白处理体外培养的细胞,分别从细胞存活率、细胞形态、细胞凋亡程度以及周期分布4?个方面阐述了藻蓝蛋白对A549细胞的影响。结果表明,藻蓝蛋白能够显著降低A549细胞的存活率与生长速率（P＜0.05）,引起细胞形态发生非正常改变;同时上调促凋亡基因Bax、Bad,下调抑凋亡基因Bcl-2、Bcl-xl的表达而诱导细胞凋亡;此外,藻蓝蛋白能够异常调控细胞周期G1/S转换点相关基因的表达而引起细胞发生G1期阻滞。研究结果揭示了藻蓝蛋白对A549肺癌细胞具有显著的抑制作用,为开发新型抗癌类功能性食品着色剂提供了必要的理论依据。