Molecular mechanisms of the chemopreventive effects of resveratrol and its analogs in carcinogenesis

Resveratrol (3,4',5-trihydroxy-trans-stilbene), a phytoalexin found in grape skins, peanuts, and red wine, has been reported to exhibit a wide range of biological and pharmacological properties. It has been speculated that dietary resveratrol could be an explanation for the so-called 'French paradox' as it may act as an antioxidant, promote nitric oxide production, inhibit platelet aggregation, and increase high-density lipoprotein cholesterol, and thereby serve as a cardioprotective agent. Recently, it has been demonstrated that resveratrol can function as a cancer chemopreventive agent, and there has been a great deal of experimental effort directed toward defining this effect. It has been shown that resveratrol and some of its analogs interfere with signal transduction pathways, modulate cell cycle-regulating proteins, and is a potent inducer of apoptosis in multiple carcinoma cell lines. This review summarizes the recent advances that have provided new insights into the molecular mechanisms underlying the promising properties of resveratrol.     

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.     

Inhibitory effects of trans-resveratrol analogs molecules on the proliferation and the cell cycle progression of human colon tumoral cells

Resveratrol may function as a cancer chemopreventive agent. However, few data are available on the antitumoral activities of its dimer, epsilon-viniferin, also present in human diet. So, the effects of resveratrol, epsilon-viniferin, of their acetylated forms (resveratrol triacetate, epsilon-viniferin pentaacetate) and of vineatrol (a wine grape extract) were compared on human adenocarcinoma colon cells. Resveratrol and resveratrol triacetate inhibit cell proliferation and arrest cell cycle. epsilon-Viniferin and epsilon-viniferin pentaacetate slightly reduce cell proliferation. Vineatrol inhibits cell proliferation and favors an accumulation in the S phase of the cell cycle. Consequently, resveratrol triacetate and vineatrol could constitute new putative anticancer agents on colon carcinoma.     

Synergistic effect of D-glucose and epidermal growth factor display on dynamic behaviors of human epithelial cells

We investigated the synergistic effect of D-glucose and epidermal growth factor (EGF) display on the dynamic cellular behaviors of morphology and migration in a culture of human epithelial cells. The time-lapse observation revealed that the cells on the D-glucose/EGF-displayed substrate were endowed with enhanced migration, accompanied with periodic changes in morphology between round and stretched shapes. Immunofluorescence staining of phosphotyrosine PY20 and vinculin was conducted to determine the intracellular localization of phosphorylated tyrosine expression and focal contact formation, respectively. On the substrate displaying D-glucose and EGF, the cells exhibited increases in the levels of the expression of phosphorylated tyrosine and the formation of focal contacts not only at the cellular periphery but also in the cell body. These findings supported the consideration that the displayed D-glucose causes the cells to be in close contact with the surface via grasping glucose transporters on the cytoplasmic membrane.     

Inhibition of Rhizomucor miehei and Candida rugosa lipases by D-glucose in esterification between L-alanine and D-glucose

A detailed kinetic study of the esterification of D-glucose with L-alanine catalyzed by lipases from Rhizomucor miehei (RML) and Candida rugosa (CRL) showed that both lipases follow the Ping-Pong Bi-Bi mechanism, in which L-alanine and D-glucose bind in subsequent steps releasing water and L-alanyl-D-glucose, with competitive substrate inhibition by D-glucose at higher concentrations leading to the formation of dead-end lipase.D-glucose complexes. An attempt to obtain the best fit of this kinetic model through curve fitting yielded good approximates of the apparent values of four important kinetic parameters: for RML-k(cat)=0.29+/-0.028x10(-3) M h(-1) mg(-1), K(m L-alanine)= 4.9+/-0.51x10(-3) M, K(m D-glucose)=0.21+/-0.018x10(-3) M, and K(i D-glucose)=1.76+/-0.19x10(-3) M; for CRL-k(cat)= 0.75+/-0.08x10(-3) M h(-1) mg(-1), K(m L-alanine)=56.2+/-5.7x10(-3) M, K(m D-glucose)=16.2+/-1.8x10(-3) M, and K(i D-glucose) =21.0+/-1.9x10(-3) M.     

人α-乳白蛋白在奶牛乳腺上皮细胞中的表达

将人α-乳白蛋白(α-LA)0.76 kb的cDNA序列连接到PSV载体SV40启动子后,构建真核表达载体hα-LA-psv.将构建的真核表达载体转染奶牛乳腺上皮细胞,Aα-乳白蛋白的表达量约为0.85 g/L.结果表明,构建的真核表达载体能够在体外培养的牛乳腺上皮细胞中高效表达Aα-乳白蛋白.     

南瓜籽多肽的制备及其对人体皮肤细胞的体外作用

以南瓜籽为原料制备南瓜籽蛋白。分别采用碱性蛋白酶、胰蛋白酶、风味蛋白酶、碱性蛋白酶-胰蛋白酶、碱性蛋白酶-风味蛋白酶酶解南瓜籽蛋白得到南瓜籽多肽。结果表明:碱性蛋白酶-胰蛋白酶酶解南瓜籽蛋白,水解度为27. 23%、多肽产率为39. 20%,均为5种酶解产物中最高;碱性蛋白酶-胰蛋白酶酶解制备的南瓜籽多肽中小于1 000 Da的多肽含量高达92. 72%,其具有较好的促进人体皮肤细胞增殖的性能及清除自由基作用,可降低细胞内活性氧含量,在人体皮肤细胞受到氧化损伤时,能起到良好的修复作用。     

重组人活性蛋白C的基因克隆、表达载体构建以及在哺乳动物细胞中的高效表达

目的研究重组人活性蛋白C的基因克隆、表达载体构建以及在哺乳动物细胞中的表达。方法用RT-PCR法从人胎肝中克隆出人蛋白C轻重链基因,用PCR突变法获得人活性蛋白C的全基因,将所得全基因连接入哺乳动物细胞表达载体,并转染293细胞研究其表达和活性。结果成功得到重组人活性蛋白C基因,并成功构建哺乳动物细胞表达载体和转染293细胞获高效表达以及相关活性数据。结论通过以上方法可以获得重组人活性蛋白C基因,并实现了在哺乳动物细胞中的高效表达。     

High hydrostatic pressure inactivation of Lactobacillus viridescens and its effects on ultrastructure of cells

The effect of high hydrostatic pressure treatment on Lactobacillus viridescens, a major spoilage micro-organism of processed meat, was investigated. When pressure was applied at 400, 500 and 600 MPa for 5 min, cell survival in MRS broth was reduced approximately by 2, 7 and 8 log cycles, respectively. The combination of high pressure and temperature increase showed synergistic effects on microbial inactivation. Empty cavities in the cell and DNA denaturation were observed after pressure treatment above 400 MPa. The level of microbial inactivation when Lb. viridescens was pressured in protein-fortified MRS broth and ham were less than half compared with the inactivation achieved in peptone water. Increasing the temperature during high-pressure treatment solved these adverse effects in the ham.     

Antiproliferative and antioxidant effects on breast cancer cells of oleuropein and its semisynthetic peracetylated derivatives

Olive leaves extracts are a natural source of polyphenols, mainly oleuropein, widely considered to be potentially beneficial for health. This study focused on evaluation of the anti-tumoural activities of some oleuropein peracetylated derivatives, obtained with “green chemical” methodologies, against two human breast cancer cell lines. MCF-7 and T-47D cells were treated with oleuropein, peracetylated oleuropein, peracetylated aglycone and peracetylated hydroxytyrosol and the effects on growth and viability were investigated. Antioxidant effects were analysed after treatment with hydrogen peroxide. The peracetylated compounds exerted higher antiproliferative effects than oleuropein, by an arrest of cell cycle progression, associated with a strong antioxidant activity. Our results demonstrate that olive leaves, a by-product of olive manufacture, may provide a precious source of chemical derivatives, obtainable by peracetylation of oleuropein derivatives, which provide beneficial properties for human health.     

Differential effects in mammalian cells induced by chemical mixtures in environmental biota as profiled using infrared spectroscopy

Environmental contaminants accumulate in many organisms and induce a number of adverse effects. As contaminants mostly occur in the environment as mixtures, it remains to be fully understood which chemical interactions induce the most important toxic responses. In this study, we set out to determine the effects of chemical contaminants extracted from Northern Gannet (Morus bassanus) eggs (collected from the UK coast from three sampling years (1987, 1990, and 1992) on cell cultures using infrared (IR) spectroscopy with computational data handling approaches. Gannet extracts were chemically analyzed for different contaminants, and MCF-7 cell lines were treated for 24 h in a dose-related manner with individual-year extracts varying in their polybrominated diphenyl ether (PBDE) to polychlorinated biphenyl (PCB) ratios. Treated cellular material was then fixed and interrogated using attenuated total reflection Fourier-transform IR (ATR-FTIR) spectroscopy; resultant IR spectra were computationally analyzed to derive dose-response relationships and to identify biomarkers associated with each contaminant mixture treatment. The results show distinct biomarkers of effect are related to each contamination scenario, with an inverse relationship with dose observed. This study suggests that specific contaminant mixtures induce cellular alterations in the DNA/RNA spectral region that are most pronounced at low doses. It also suggests alterations in the "biochemical-cell fingerprint" of IR spectra can be indicative of mixture exposures.     

Adjudin, a potential male contraceptive, exerts its effects locally in the seminiferous epithelium of mammalian testes

Adjudin is a derivative of 1H-indazole-3-carboxylic acid that was shown to have potent anti-spermatogenic activity in rats, rabbits, and dogs. It exerts its effects most notably locally in the apical compartment of the seminiferous epithelium, behind the blood-testis barrier, by disrupting adhesion of germ cells, most notably spermatids to the Sertoli cells, thereby inducing release of immature spermatids from the epithelium that leads to infertility. After adjudin is metabolized, the remaining spermatogonial stem cells and spermatogonia repopulate the seminiferous epithelium gradually via spermatogonial self-renewal and differentiation, to be followed by meiosis and spermiogenesis, and thus fertility rebounds. Recent studies in rats have demonstrated unequivocally that the primary and initial cellular target of adjudin in the testis is the apical ectoplasmic specialization, a testis-specific anchoring junction type restricted to the interface between Sertoli cells and elongating spermatids (from step 8 to 19 spermatids). In this review, we highlight some of the recent advances and obstacles regarding the possible use of adjudin as a male contraceptive.     

基于哺乳动物细胞系的重组乙酰胆碱酯酶表达载体构建研究

：目的 构建具有不同信号肽、载体骨架元件以及乙酰胆碱酯酶编码基因序列的真核表达载体,为基于哺乳动物细胞系表达重组乙酰胆碱酯酶提供前期研究基础。方法 通过NCBI数据库查询苍蝇头部、电鳗鱼发电器官来源的乙酰胆碱酯酶基因序列(mdAChE和eleelAChE),经密码子优化后,选择Humaninsulin、小鼠重链、Human CD33 3种信号肽序列,将其与合成的上述目的基因连接后分别与pCMV3、pcDNA3.1(+)、pcDNA3.4 3种载体骨架元件进行组合,构建重组乙酰胆碱酯酶的表达载体,随后分别在CHO-S、Expi293F细胞系中进行瞬时转染表达,产物采用镍柱亲和纯化后进行SDS-PAGE与WB分析鉴定。结果 经菌落PCR及DNA测序鉴定,成功构建了4种重组mdAChE酶的表达载体以及3种重组eleelAChE酶的表达载体。SDS-PAGE、western blot的结果表明,基于pcDNA3.1(+)和pcDNA3.4载体骨架元件的重组表达载体可实现重组mdAChE和eleelAChE酶的可溶表达;以pCMV3为载体骨架元件的表达载体,仅在以Human CD33为信号肽时,在CHO-S细胞系中实现重组mdAChE酶的可溶表达,其余情况下均未见有效表达。结论 实现了昆虫、鱼类来源的重组乙酰胆碱酯酶在哺乳动物细胞系的可溶性表达,发现载体骨架元件、信号肽类型对其重组表达具有重要影响,CHO-S以及Expi293F细胞均适合重组乙酰胆碱酯酶的表达,后续还需对影响其酶活、农药敏感性的关键限制性因素开展深入地研究。     

金雀异黄素对iNOS表达影响与抑制胃癌细胞增殖作用研究

为研究金雀异黄素对人胃腺癌细胞SGC 790 1增殖、DNA合成、一氧化氮产生量、一氧化氮合酶活性及其对诱导型一氧化氮合酶 (inducednitricoxidesynthase ,iNOS)基因表达的影响 ,应用MTT、3 H TdR掺入、DNA琼脂糖电泳、分光光度法、免疫组化及RT PCR方法 ,研究Gen抑制癌细胞生长的机制。结果表明Gen抑制SGC 790 1细胞的增殖、DNA合成 ,诱导细胞凋亡 ,并可显著诱导iNOSmRNA转录、增加iNOS蛋白表达 ,促进一氧化氮产生 ,提高一氧化氮合酶活性。为将Gen应用于胃腺癌的化学防治提供了实验依据     

The conceptus increases secreted phosphoprotein 1 gene expression in the mouse uterus during the progression of decidualization mainly due to its effects on uterine natural killer cells

Within the mouse endometrium, secreted phosphoprotein 1 (SPP1) gene expression is mainly expressed in the luminal epithelium and some macrophages around the onset of implantation. However, during the progression of decidualization, it is expressed mainly in the mesometrial decidua. To date, the precise cell types responsible for the expression in the mesometrial decidua has not been absolutely identified. The goal of the present study was to assess the expression of SPP1 in uteri of pregnant mice (decidua) during the progression of decidualization and compared it with those undergoing artificially induced decidualization (deciduoma). Significantly (P<0.05) greater steady-state levels of SPP1 mRNA were seen in the decidua when compared with deciduoma. Further, in the decidua, the majority of the SPP1 protein was localized within a subpopulation of granulated uterine natural killer (uNK) cells but not co-localized to their granules. However, in addition to being localized to uNK cells, SPP1 protein was also detected in another cell type(s) that were not epidermal growth factor-like containing mucin-like hormone receptor-like sequence 1 protein-positive immune cells that are known to be present in the uterus at this time. Finally, decidual SPP1 expression dramatically decreased in uteri of interleukin-15-deficient mice that lack uNK cells. In conclusion, SPP1 expression is greater in the mouse decidua when compared with the deciduoma after the onset of implantation during the progression of decidualization. Finally, uNK cells were found to be the major source of SPP1 in the pregnant uterus during decidualization. SPP1 might play a key role in uNK killer cell functions in the uterus during decidualization.     

The mammalian target of rapamycin pathway and its role in molecular nutrition regulation

Mammalian target of rapamycin (mTOR) is a protein serine-threonine kinase that functions as a central element in signaling pathway involved in control of cell growth and proliferation. mTOR exists in at least two distinct multi-protein complexes, mTORC1 and mTORC2. mTOR kinase controls the translation machinery, in response to nutrients and growth factors, via activation of p70 ribosomal S6 kinase and inhibition of eukaryotic initiation factor-4E-binding protein. In this report, we review the mTOR signaling pathway and its interaction with food intake, insulin resistance, lifespan and adipogenic regulation during the molecular nutrition regulation.