不同分化胃癌细胞系中间隙连接蛋白的表达

目的探讨间隙连接蛋白（Cx）Cx26、Cx32、Cx43、Cx45在转化的人胃细胞系（GES-1）、胃高分化腺癌细胞系（N87）和胃低分化腺癌细胞系（BGC-823）中的表达及其与胃癌发生、发展的关系。方法采用间接免疫荧光方法检测Cx26、Cx32、Cx43、Cx45在不同分化程度胃癌细胞株中的表达，并分析该蛋白表达与胃癌发生、发展的关系。结果在不同分化胃癌细胞株中。Cx26、Cx32、Cx43、Cx45表达呈现1个由高水平到低水平表达直至无表达的梯度分布，既Cx26、cx32、Cx43、Cx45在GES-1中高水平表达，在N87表达减少，在BGC-823中无表达，并且表达部位有差异。结论Cx26、Cx32、Cx43、Cx45的表达与胃癌细胞的分化关系密切，在胃癌的发生、发展中有一定作用。     

Perfluorooctanoic acid disrupts gap junction intercellular communication and induces reactive oxygen species formation and apoptosis in mouse ovaries

Perfluorooctanoic acid (PFOA) is a member of the perfluoroalkyl acid family of compounds. Due to the presence of strong carbon–fluorine bonds, it is practically nonbiodegradable and highly persistent in the environment. PFOA has been detected in the follicular fluid of women, and positively associated with reduced fecundability and infertility. However, there are no reports concerning the experimental evaluation of PFOA on oocyte toxicity in mammals. The aim of the present study was to determine if PFOA is able to induce oxidative stress in fetal ovaries and cause apoptosis in oocytes in vitro. In addition, since inhibition of the gap junction intercellular communication (GJIC) by PFOA has been demonstrated in liver cells in vivo and in vitro, the effect of PFOA on the GJIC between the oocyte and its supportive cumulus cells was studied. Results show that PFOA induced oocyte apoptosis and necrosis in vitro (medium lethal concentration, LC₅₀ = 112.8 μM), as evaluated with Annexin‐V‐Alexa 508 in combination with BOBO‐1 staining. Reactive oxygen species (ROS) levels, as assessed by DCFH‐DA, increased significantly in fetal ovaries exposed to ¼ LC₅₀ (28.2 μM, a noncytotoxic and relevant occupational exposure concentration) and LC₅₀ PFOA ex vivo. This perfluorinated compound also caused the blockage of GJIC in cumulus cells‐oocyte complexes (COCs) obtained from female mice exposed in vivo, as evaluated by calcein transfer from cumulus cells to the oocyte. The ability of PFOA of disrupting the GJIC in COCs, generating ROS in the fetal ovary and causing apoptosis and necrosis in mammal's oocytes, might account for the reported association between increasing maternal plasma concentrations of PFOA with reduced fertility in women.     

急性白血病化疗前后与正常人骨髓基质细胞间通讯的改变

目的 观察急性白血病化疗前后与正常人骨髓基质细胞间隙连接蛋白43 (connexin43, Cx43)表达的变化及通讯功能的改变.方法 体外培养初发急性白血病化疗前及化疗后完全缓解的与正常人的骨髓基质细胞,采用免疫细胞化学方法观察三者之间Cx43表达的变化;采用细胞划痕染料传输技术比较三者之间间隙连接细胞间通讯(gap junction intercellular communication, GJIC)功能的差异.结果 正常人、急性白血病化疗前及化疗后完全缓解的骨髓基质细胞上Cx43表达的阳性率分别为(88.0±3.5)%、(12.0±2.4) %和(52.0±3.1) %;基质细胞上Cx43蛋白的光密度值分别为(175.08±8.34)、(45.42±3.71)及(94.33±7.20);染料传输的细胞数分别为(9.20±0.35)、(1.84±0.33)和(4.07±0.53).结论 急性白血病骨髓基质细胞间通讯功能较正常人及化疗后完全缓解急性白血病骨髓基质细胞明显减弱.     

Chemoprevention of liver cancer by plant polyphenols

Primary liver cancer or hepatocellular carcinoma (HCC) is one of the most frequent tumors representing the fifth commonest malignancy worldwide and the third cause of mortality from cancer. Currently, the treatments for HCC are not so effective and new strategies are needed for its fight. Chemoprevention, the use of natural or synthetic chemical agents to reverse, suppress or prevent carcinogenesis is considered an important way for confronting HCC. Many of the chemopreventive agents are phytochemicals, namely non-nutritive plant chemicals with protective or disease preventive properties. In this review, we focus on plant polyphenols, one of the most important classes of phytochemicals, their chemopreventive properties against HCC and discuss the molecular mechanisms accounting for this activity.     

(-)-Epicatechin effects in rat liver epithelial cells: stimulation of gap junctional communication and counteraction of its loss due to the tumor promoter 12-O-tetradecanoylphorbol-13-acetate

Gap junctional intercellular communication (GJIC) is a direct signaling pathway for neighboring cells. Disturbances in GJIC are suggested to play a role in carcinogenesis and may be involved in cardiac arrhythmia. Tumor promoters like 12-O-tetradecanoylphorbol-13-acetate (TPA) are capable of inhibiting GJIC, whereas GJIC is stimulated by several micronutrients like genistein, retinoids or carotenoids. (-)-Epicatechin (4-40 microM), a major flavonoid in cocoa and green tea, exhibited stimulatory effects on GJIC in WB-F344 rat liver epithelial cells after 24-72hr of incubation; no change was observed after 90 min. However, treatment of cells for 90 min with TPA (5 or 10nM) led to complete loss of GJIC, whereas 40% loss was found with 1nM. These inhibitory effects of TPA were largely suppressed when (-)-epicatechin or genistein (40 microM) were present during the incubation. In communicating WB-F344 cells, most of the major gap junction protein connexin43 (Cx43) was located in the plasma membrane. When the cells were exposed to TPA, considerably less protein was found in the membrane. Such a delocalization of Cx43 proteins was not observed when TPA was coincubated with the flavonoids, (-)-epicatechin or genistein. It is concluded that TPA affects Cx43 trafficking between cellular compartments, and that this effect is counteracted by (-)-epicatechin or genistein.     

ATRA调节人异位子宫内膜间质细胞GJIC Connexin基因、蛋白的作用及意义

目的:探讨全反式维甲酸(ATRA)对人异位子宫内膜间质细胞间隙连接细胞间通讯(GJIC)、connexin基因、蛋白的调节作用及意义。方法:取24例子宫内膜异位症患者卵巢处异位内膜标本,分离纯化得到间质细胞,分别用0.1mmol/L、1mmol/L、10mmol/LATRA处理24h、48h、72h、96h、120h,同时设置空白对照组,采用荧光漂白后恢复技术检测异位内膜间质细胞的GJIC功能,并检测与GJIC功能密切相关的Cx43、Cx26、Cx32的基因及蛋白表达。结果:ATRA处理72h内,1mmol/L、10mmol/L组的异位内膜间质细胞荧光恢复功能明显增强;0.1mmol/LATRA组的异位内膜间质细胞荧光恢复功能无明显变化。未经ATRA处理的异位内膜间质细胞中无Cx43、Cx26、Cx32的mRNA及蛋白表达;经1mmol/LATRA处理后,异位内膜间质细胞中检测到Cx43mRNA和蛋白表达,但未见Cx26、Cx32的mRNA及蛋白表达。结论:ATRA能选择性地诱导Cx43基因及蛋白表达,从而有效上调异位内膜间质细胞的GJIC功能;ATRA可能是治疗子宫内膜异位症的潜在药物。     

三七皂甙对急性肝功能衰竭大鼠肝细胞缝隙连接蛋白/细胞间缝隙连接通讯的影响

目的从细胞间缝隙连接通讯的角度,探讨三七皂甙（panax notoginseng saponins,PNS）在急性肝功能衰竭（AHF）修复中的作用及机制。方法雄性Wistar大鼠200只（SPF级,江西省实验动物质量检测中心提供）,体重180～200g,适应性喂养1周,随机分成3组：对照组（n=30）,模型组（n=100）,三七皂甙组（PNS组,n=70）。模型组和PNS组采用四氯化碳腹腔注射法建立AHF模型,分别在造模后1、3、7、10和14d5个时间点开腹,采取肝组织行免疫组化检查Cx32、切开标记荧光染料传输（IL/DT）查GJIC功能。结果动物在造模后立即出现精神萎靡、活动及摄食减少、嗜睡,严重者有全身多脏器出血、昏迷甚至死亡。PNS组与模型组的病死率差异有显著性P（〈0.05）。Cx32的免疫组化显示,造模初期PNS组的Cx32分布及数量与模型组相似,随着时间的推移,数量呈进行性增加的趋势。荧光染料传输发现,模型组的染料传输能力在造模后比对照组明显减低（P〈0.01）,并在第3天达到最低程度,此后虽逐渐恢复,但到第14天与对照组间差异仍有极显著性（P〈0.01）;PNS组的染料传输在造模后第1天比对照组明显减低（P〈0.01）,程度与模型组相仿（P〉0.05）,但与模型组不同的是PNS组在第3天由荧光染料传输所反映的GJIC功能已经开始恢复,与模型组相比差异有极显著性（P〈0.01）,到第14天恢复正常,与对照组间差异无显著性（P〉0.05）。结论PNS可以上调AHF大鼠肝细胞间的CX/GJIC,从而加快损伤中后期肝细胞间的信息交流,促进肝脏细胞的增生及肝组织结构的重建。     

细胞间隙通讯对重离子辐射效应的影响

目的 探索细胞间隙通讯(GJIC)对重离子辐射细胞效应的影响及其机制。方法 受到不同试剂处理的AG1522细胞和HSG细胞在高能碳离子束辐照后,检测其细胞损伤。结果 重离子辐照对细胞产生致死性损伤、细胞周期的阻滞,且AG1522比HSG具有更高的辐射敏感性。对AG1522细胞单层,GJIC可以正向调控辐射损伤。但对HSG细胞单层,受到增强的GJIC则对细胞具有辐射保护作用。另外,DMSO降低了AG1522细胞的微核率,但PTIO可增强HSG的微核率。结论 GJIC对正常母细胞和肿瘤细胞的辐射损伤具有不同的作用,ROS和NO是其中重要的信号因子。     

Evaluation of tumour promoting potency of fish borne toxaphene residues, as compared to technical toxaphene and UV-irradiated toxaphene

In this study the potential impact of food chain-based biotransformation and physico-chemical weathering of toxaphene on its tumour promoting potential was investigated in vitro and in vivo. Human exposure to toxaphene is mainly through consumption of contaminated fish, therefore fish-borne residues of toxaphene (cod liver extract, CLE) were prepared by exposing cod to technical toxaphene (TT) for 63 days. UV-irradiated toxaphene (uvT) was included to represent a physico-chemical weathered toxaphene mixture. In vitro, TT, uvT and CLE all showed a dose- and time-dependent inhibition of gap junctional intercellular communication (GJIC) with a relative potency of CLE>TT=uvT. Tumour promoting potency was further studied in vivo in a medium term two-stage initiation/promotion bioassay in female Sprague-Dawley rats, using an increase in altered hepatic foci positive for glutathione-S-transferase-P (AHF-GST-P) as read out. No increase in AHF-GST-P occurred following exposure to either TT, uvT, or CLE, except for the positive control group (2,3,7,8-TCDD). Based on this study the no observed adverse effect level (NOAEL) for tumour promoting potency is at least 12.5mg/kg/week, or higher for CLE. Considering current human exposure levels in Europe it is doubtful that consumption of fish at current levels of toxaphene contamination give rise to human health risk.     

Inhibition of gap junctional intercellular communication by perfluorinated compounds in rat liver and dolphin kidney epithelial cell lines in vitro and Sprague-Dawley rats in vivo.

Gap junctional intercellular communication (GJIC) is the major pathway of intercellular signal transduction, and is thus important for normal cell growth and function. Recent studies have revealed a global distribution of some perfluorinated organic compounds, especially perfluorooctane sulfonic acid (PFOS) in the environment. Because other perfluoroalkanes had been shown to inhibit GJIC, the effects of PFOS and related sulfonated fluorochemicals on GJIC were studied using a rat liver epithelial cell line (WB-F344) and a dolphin kidney epithelial cell line (CDK). In vivo effects on GJIC were studied in Sprague-Dawley rats orally exposed to PFOS for 3 days or 3 weeks. Effects on GJIC were measured using the scrape loading dye technique. PFOS, perfluorooctane sulfonamide (PFOSA), and perfluorohexane sulfonic acid (PFHA) were found to inhibit GJIC in a dose-dependent fashion, and this inhibition occurred rapidly and was reversible. Perfluorobutane sulfonic acid (PFBS) showed no significant effects on GJIC within the concentration range tested. A structure activity relationship was established among all 4 tested compounds, indicating that the inhibitory effect was determined by the length of fluorinated tail and not by the nature of the functional group. The results of the studies of the 2 cell lines and the in vivo exposure were comparable, suggesting that the inhibitory effects of the selected perfluorinated compounds on GJIC were neither species- nor tissue-specific and can occur both in vitro and in vivo.