Contribution of different molecular weight fractions to anticancer effect of sweet potato protein hydrolysates by six proteases on HT‐29 colon cancer cells

The contribution of different molecular weight fractions to anticancer effect of sweet potato protein hydrolysates (SPPH) by six proteases on HT‐29 colon cancer cells was investigated. SPPH prepared by six proteases showed certain antiproliferation effect on HT‐29 cells. Compared with other five proteases, SPPH by Alcalase exhibited the highest antiproliferation effect with the lowest IC₅₀ value of 119.72 μg mL^?1. SPPH by Alcalase was further separated into four fractions (>10, 5–10, 3–5 and <3 kDa), and <3 kDa fractions showed the strongest antiproliferation effect, which was 43.87% at 100 μg mL^?1 (P < 0.05). The <3 kDa fractions could cause G2/M cell cycle arrest with increased p21 expression and induce apoptosis via decreasing Bcl‐2 expression, increasing Bax expression and inducing caspase‐3 activation in HT‐29 cells. In addition, <3 kDa fractions could significantly inhibit cell migration of HT‐29 cells. Thus, SPPH might be potentially used as a natural supplement in functional foods.     

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     

抑制人结肠癌HT-29细胞增殖乳酸菌有效成分的筛选

以鼠李糖乳杆菌（Lactobacillus rhamnosus）GG（LGG）为阳性对照,4株具有潜在抗结肠癌功效的乳酸菌为研究对象,提取其细胞壁及细胞质,通过3-（4,5-二甲基噻唑-2）-2,5-二苯基四氮唑溴盐（MTT）法初步筛选具备抑制HT-29细胞增殖能力的成分,再通过分析提取成分对HT-29细胞DNA损伤、细胞死亡及周期的影响,获得具有抗结肠癌作用的有效成分。结果表明,与阳性对照LGG相比,乳酸菌X11、X12、M5、K14的细胞壁和乳酸菌M5、K14的细胞质对HT-29细胞增殖能力有显著抑制作用（P＜0.05）;HT-29细胞经乳酸菌细胞壁或细胞质（蛋白质含量为80 μg/mL）处理48 h后,脱氧核糖核酸（DNA）出现了明显的弥散拖尾形态;乳酸菌X12、M5和K14细胞壁诱导HT-29细胞凋亡,并调控癌细胞周期分布。通过筛选最终获得乳酸菌X12、M5和K14的细胞壁成分具有抗结肠癌作用。     

玻璃和不锈钢容器发酵水豆豉的乙醇提取物对结肠癌细胞的体外凋亡诱导效果比较

对玻璃和不锈钢容器发酵水豆豉的体外结肠癌抑制效果进行了研究。两种水豆豉乙醇提取物中的染料木素和棉籽糖含量高于原料大豆乙醇提取物（RS）,玻璃容器发酵水豆豉乙醇提取物（GVFS）中的染料木素和棉籽糖含量高于不锈钢容器发酵水豆豉乙醇提取物（SSVFS）。通过对体外培养的HT-29和HCT-116结肠癌细胞进行实验,得出GVFS具有最强的结肠癌细胞生长抑制效果,同时SSVFS对结肠癌细胞的生长抑制效果高于RS。进一步的RT-PCR实验也显示GVFS、SSVFS和RS均可以上调结肠癌细胞的Bax、Caspase-3、Caspase-8、Caspase-9 mRNA表达,同时下调Bcl-2、Bcl-x L表达,且GVFS的作用强于SSVFS和RS。实验结果显示,GVFS具有最高的染料木素和棉籽糖含量,同时具有最高的癌细胞增殖抑制效果和凋亡诱导效果,玻璃容器可以用来发酵具有高生理活性作用的水豆豉。      

下关生沱茶的HT-29人体结肠癌细胞的体外抗癌效果

对2005年,2007年和2009年产下关生沱茶,进行HT-29结肠癌细胞体外抗癌效果评价,通过MTT试验、细胞生长率试验和RT-PCR分析验证其抗癌效果。200μg／mL质量浓度下2005年产下关生沱茶（85％）表现出对HT-29结肠癌细胞最强的生长抑制效果。RT—PCR检查Bax,Bcl-2基因表达情况显示2005年产下关生沱茶对HT-29结肠癌细胞有最强的诱其凋亡的能力。由此得出,储存时间越长的沱茶具有更好的抗癌预防效果。     

瘤果黑种草子总黄酮成分对结肠癌细胞株SW480增殖、迁移能力的影响及机制

目的探讨瘤果黑种草子总黄酮成分对人结肠癌细胞株SW480增殖、迁移能力的影响及可能的作用机制。方法用不同浓度的瘤果黑种草子总黄酮成分药物干预的结肠癌细胞株SW480,MTT法检测SW480细胞株的增殖能力,倒置显微镜观察对结肠癌细胞株SW480细胞形态的影响,划痕实验检测对细胞的迁移能力的影响,实时荧光定量PCR检测瘤果黑种草子总黄酮成分对细胞中BECN1、MAPILC3B基因表达的影响。结果瘤果黑种草子总黄酮对人结肠癌细胞株SW480体外增殖的抑制作用明显,并呈浓度依赖性抑制人结肠癌细胞株SW480的增殖,在25μg/mL时达到最大的抑制率,抑制率为81.28%。倒置显微镜观察,用瘤果黑种草子总黄酮成分药物干预后,人结肠癌细胞株SW480形态学发生明显变化,瘤果黑种草子总黄酮成分可抑制人结肠癌细胞株SW480迁移能力,同时,可上调自噬相关基因BECN1、MAPILC3B的表达量。结论瘤果黑种草子总黄酮成分可抑制人结肠癌细胞株SW480的增殖、迁移能力,机制可能与能影响细胞中BECN1、MAPILC3B基因表达量有关。     

Enzyme inactivation of tomato juice by ohmic heating and its effects on physico‐chemical characteristics of concentrated tomato paste

Fresh juice of fully ripe tomato was subjected to ohmic heat (OH) treatment (90°C for 1 min) and the effectiveness of treatment was compared with conventional hot break (CT) treatment (90°C for 5 min). PG (Polygalacturonase) and PME (Pectin methyl esterase) enzyme inactivation achieved by the OH (1 min.) was similar as compared to CT of 5 min. During the kinetic analysis it was observed that the inactivation of PME & PG enzyme and degradation of ascorbic acid followed first order trend in ohmic as well as conventional treatment of tomato juice, however total color change (DE) was found to follow least‐squares non‐linear parameter algorithm behavior. Thermal treatments leads to the increased release of phyto‐chemicals from the matrix which results in a significant (p<0.01) increase in lycopene content during the early phases of the treatments. The Paste (28±0.5 °Brix) obtained after pre‐treatment was analyzed for lycopene, ascorbic acid content and apparent viscosity and color. OH Paste was found more viscous than CT treatment with maximum viscosity of 2.33×103 mPa‐s. The color of OH treated paste was bright red as compared to CT treatment, however the lycopene and ascorbic acid content of paste were found similar in OH and CT. Based on results of present study it is concluded that the ohmic treatment may be applied as an efficient alternative to the conventional method of enzyme inactivation in tomato juice.     

Phytate hydrolysate induces circumferential F‐actin ring formation at cell–cell contacts by a Rho‐associated kinase‐dependent mechanism in colorectal cancer HT‐29 cells

Phytate (inositol hexa‐phosphate or IP6) possessing anticancer activity is hydrolyzed by phytase in intestinal microbes and the metabolites are distributed throughout the colon. Cellular circumferential F‐actin rings, which are involved in cell polarity and structure, are lost early during tumorigenesis. We investigated F‐actin ring formation by the phytate hydrolysate in colorectal cancer HT‐29 cells to explore the novel mechanisms underlying the phytate‐mediated anticancer function. The phytate hydrolysate, but not inositol or phytate, induced F‐actin ring formation with a peak at 10 min in the cells and was associated with phosphorylation of myosin regulatory light chain. F‐actin ring formation and myosin regulatory light chain phosphorylation by the phytate hydrolysate were suppressed by inhibitors of Rho‐associated kinase (ROCK), Janus kinase (JAK), c‐Jun N‐terminal kinase (JNK), and protein kinase Cδ (PKCδ). Activation of ROCK and JAK, but not JNK or PKCδ, was observed at 10 min and/or earlier after stimulation with the phytate hydrolysate. Altogether, the phytate hydrolysate induces circumferential F‐actin ring formation through a ROCK‐dependent myosin II activation in the HT‐29 cells, which requires JAK activation and basal activities of JNK and PKC. Hydrolysis products of phytate in the intestine may contribute to anticancer function of phytate.     

American India Pale Ale matrix rich in xanthohumol is potent in suppressing proliferation and elevating apoptosis of human colon cancer cells

American India Pale Ales (IPAs) with and without addition of dark/roasted malts (DRM) and dry hopping (DP) were analysed to determine whether these processes will increase total phenolic content (TP), antioxidant capacity (AA) and the levels of bioactive compounds (xanthohumol, XN and isoxanthohumol, IX). In addition, bioactivity of whole beer matrices, that is, the ‘phytochemical team approach,’ was compared to isolated compounds, the ‘silver bullet approach,’ by measuring antiproliferative and pro‐apoptotic properties using HCT 116 human colon cancer cells. DP and addition of DRM elevated the XN, IX, TP and AA. Dark malts reduced losses in XN and TP due to filtration. Xanthohumol content positively correlated with phenolic content (r = 0.88, P = 0.0002), indicating that the processes which increased xanthohumol content also elevated other bioactive compounds in beer. However, whole extract from IPAs were more potent in suppressing proliferation and elevating apoptosis in colon cancer cells compared with xanthohumol alone.     

Volatile compounds and changes in flavour‐related enzymes during cold storage of high‐intensity pulsed electric field‐ and heat‐processed tomato juices

BACKGROUND: The effects of high‐intensity pulsed electric field (HIPEF) processing (35 kV cm^?1 for 1500 µs, using 4 µs bipolar pulses at 100 Hz) on the production of volatile compounds and flavour‐related enzymes in tomato juice were investigated and compared with those of thermal processing (90 °C for 30 or 60 s). RESULTS: Tomato juice treated by HIPEF showed lower residual lipoxygenase (LOX) activity (70.2%) than juice heated at 90 °C for 60 s (80.1%) or 30 s (93.2%). In contrast, hydroperoxide lyase (HPL) was almost completely inactivated when the juice was subjected to 90 °C for 60 s, whereas roughly 50% of the control tomato juice was depleted after HIPEF treatment or thermal processing at 90 °C for 30 s. A slight decrease was observed in the initial LOX activity of treated and untreated samples during storage, whereas initial HPL activity was strongly affected over time. CONCLUSION: HIPEF‐treated juice exhibited higher levels of compounds contributing to tomato aroma than untreated and heat‐treated juices throughout storage. Thus HIPEF processing can preserve flavour quality and stability of tomato juice compared with conventional thermal treatments. Copyright © 2010 Society of Chemical Industry     

地皮菜中一种新型水应激蛋白基因的克隆表达及其抗人结肠癌细胞SW480的作用

利用聚合酶链式反应（polymerase chain reaction,PCR）扩增出地皮菜（Nostoc commune Vauch.）一种新型水应激蛋白（water stress protein,WSP）的基因（GenBank 序列号：KF003026）,连接到原核表达载体pET28a上,测序鉴定后转化入大肠杆菌BL21,获得一种新型水应激蛋白表达工程菌;经异丙基-β-D-硫代半乳糖苷（isopropyl-β-D-thiogalactopyranoside,IPTG）诱导表达及镍离子亲和层析柱（Ni-NTA）纯化后,得到了带6×His标签、分子质量大小为40 kD的可溶性目的蛋白,称其为重组水应激蛋白1（recombinant water stress protein 1,Re-WSP1）。细胞增殖抑制实验结果表明,Re-WSP1蛋白可以抑制结肠癌细胞SW480的增殖,而对正常结肠上皮FHC细胞无明显作用;DAPI细胞核染色结果表明,该蛋白能够诱导SW480细胞凋亡小体的形成;Western blotting结果显示,Re-WSP1蛋白能够促进Procaspase-3和Procaspase-8的活化剪切。以上结果表明：Re-WSP1蛋白能够明显的抑制结肠癌SW480细胞的增殖,并可能通过Caspase依赖途径诱导SW480细胞凋亡。     

Xanthohumol induces apoptosis in cultured 40-16 human colon cancer cells by activation of the death receptor- and mitochondrial pathway

Xanthohumol (XN) is one of the major prenylflavonoids found in hop cones (Humulus lupulus L.). In this study, we investigated the cell growth inhibitory potential of XN on cultured human colon cancer cells. Cell proliferation was measured by sulforhodamine B staining. Poly(ADP-ribose)polymerase (PARP) cleavage, activation of caspases-3, -7, -8, and -9, and Bcl-2 family protein expression were detected by Western blot analyses. XN significantly reduced proliferation of the HCT 116-derived colon cancer cell line 40--16. Half-maximal inhibitory concentrations decreased from 4.1 microM after 24 h treatment to 3.6 and 2.6 microM after 48 and 72 h incubation, respectively. Treatment with 15 microM XN for 48 h and with 5 microM for 72 h led to the detection of the cleaved 89 kDa fragment of 116 kDa PARP as an indication of apoptosis induction. Concomitantly, we observed activation and cleavage of the effector caspases-3 and -7, induced by activation of the initiator caspases -8 and -9. Expression of anti-apoptotic Bcl-2 was down regulated when the cells were treated with XN for 48--72 h. We conclude that induction of apoptosis by downregulation of Bcl-2 and activation of the caspase cascade may contribute to the chemopreventive or therapeutic potential of XN.     

Cranberry extract and quercetin modulate the expression of cyclooxygenase‐2 (COX‐2) and IκBα in human colon cancer cells

BACKGROUND: Cranberry (Vaccinium marcocarpon) fruit and quercetin, a major flavonoid found in cranberries, are likely contributors to chemoprevention, and their anti‐inflammatory activities may play a potential role in colon cancer prevention. The aim of this study was to examine the effect of cranberry extract and quercetin on basal expression of cyclooxygenase‐2 (COX‐2) and IκBα as well as the effect on phorbol 12‐myristate 13‐acetate (PMA)‐induced COX‐2 expression in colon cancer cells. RESULTS: HT‐29 human colon adenocarcinoma cells were treated with various concentrations of cranberry extract or quercetin and/or PMA, and the protein expression of COX‐2 and IκBα was determined. The results indicated that cranberry extract and quercetin decreased COX‐2 expression and suppressed degradation of IκBα in unstimulated cells. In PMA‐stimulated cells, cranberry extract was also able to decrease COX‐2 expression and suppress degradation of IκBα. CONCLUSION: The results suggest that a possible mechanism involved in the anti‐cancer activity of cranberry and quercetin is partly mediated through its anti‐inflammatory action. These findings indicate that cranberry and quercetin may reduce the risk of colon cancer possibly by suppressing inflammatory responses. Copyright © 2008 Society of Chemical Industry