维生素E和微量元素Se对人肝癌细胞生长,分化及其癌基因…

本工作观察了体外环境中不同水平的维生素Ｅ和微量元素Ｓｅ对人肝癌细胞株（ＳＭＭＣ－７７２１）生长,分经和其癌基因（Ｎ－ｒａｓ,ｃ－ｍｙｃ）表达水平的影响,实验结果表明：高水平维生素Ｅ（２．４、９．２、２４：０ｎｍｏｌ／Ｌ）和Ｓｅ（０．１５,０．３０,０．６０ｎｍｏｌ／Ｌ）对肝癌细胞的集落形成率具有明显的抑制作用;生化分析显示高水平维生素Ｅ微量元素Ｓｅ均可明显抑制环境中脂质过氧化的水平,Ｓｅ对癌细胞甲     

维甲酸对鼻咽癌细胞生长、表型和瘤基因表达的作用

研究了维甲酸（ＲＡ）对鼻咽癌细胞生长、表型和癌基因表达的作用．用ＲＡ诱导鼻咽癌细胞,绘制诱导前后的细胞曲线,观察细胞形态,并用Ｎｏｒｔｈｅｒｎ杂交和ＤＮａｓｅⅠ超敏感区分析法检测基因表达和调控．结果表明,ＲＡ能显著抑制鼻咽癌细胞的生长,前５ｄ下降约５０％．ＲＡ处理后的细胞从典型的多边形形态变成扁平、细长,类似纤维细胞状的形态．ＲＡ诱导前ｃ－ｍｙｃ基因和ｃ－Ｈａ－ｒａｓ基因ＨＮＥ２细胞中高表达,而诱导后ｃ－ｍｙｃ基因表达水平急剧下降,ｃ－Ｈａ－ｒａｓ基因无明显改变．在实验中还发现ＲＡ诱导前后的ｃ－ｍｙｃ基因和ｃ－Ｈａ－ｒａｓ基因中一些重要的超敏感位点和它们的功能．由实验结果可得到如下结论：ＲＡ能促进鼻咽癌细胞分化,通过对染色体上调控位点的作用来抑制ｃ－ｍｙｃ基因的表达,ＤＮａｓｅⅠ超敏感位点与细胞的分化程度、细胞的组织特异性和基因表达状态有关,ｃ－ｍｙｃ基因可通过不同的调控方式而失活．     

箬叶多糖及其化学修饰物、亚硒酸钠和GSH对Cu~(2+)诱导的LDL氧化修饰的保护作用

研究了箬叶多糖ＦⅢ－ａ及其化学修饰物、亚硒酸钠和ＧＳＨ对Ｃｕ２＋诱导的低密度脂蛋白氧化修饰的保护作用．其结果表明箬叶多糖、硫酸酯多糖、硒酸酯多糖可显著抑制脂质过氧化产物（ＴＢＡＲＳ）及荧光物质的生成,彼此之间无明显差异．但对ＶＥ的消耗有着不同的保护作用,其顺序是ＦⅢ－ａ＞Ｓ－ＦⅢ－ａ＞Ｓｅ－ＦⅢ－ａ,并且具有明显的量效关系．硒或ＧＳＨ对Ｃｕ２＋诱导的ＬＤＬ氧化修饰无明显的抑制,但联合使用在０．１２５ｍｍｏｌ／ＬＮａ２ＳｅＯ３和０．２ｍｍｏｌ／ＬＧＳＨ及１２．５μｍｏｌ／ＬＮａ２ＳｅＯ３和０．０２ｍｍｏｌ／ＬＧＳＨ的浓度下能强烈地抑制ＴＢＡＲＳ的生成,甚至比正常的ＬＤＬ还要低．但是对ＶＥ的消耗只有较弱的保护作用,硒酸酯多糖与此相似．Ｎａ２ＳｅＯ３在０．１２５ｍｍｏｌ／Ｌ时可以明显抑制荧光物质的生成．     

细胞松驰素B促微丝解聚对DNA合成的作用

利用微丝（ｍｉｃｒｏｆｉｌａｍｅｎｔ,ＭＦ）解聚药物细胞松驰素Ｂ（ｃｙｔｏｃｈａｌａｓｉｎＢ,ＣＢ）处理Ｇ_０期小鼠Ｃ_３Ｈ_（１０）Ｔ_（１／２）成纤维细胞,对Ｇ_０至Ｓ期ＤＮＡ合成,胸腺嘧啶核苷激酶（ｔｈｙｍｉｄｉｎｅｋｉｎａｓｅ,ＴＫ）活性、ＴＫ基因表达、钙调素（ｃａｌｍｏｄｕｌｉｎ,ＣａＭ）水平和一些细胞周期早期基因的表达进行了观察,Ｇ_０期细胞经３ｍｇ／ＬＣＢ处理２ｈ,促ＭＦ解聚增强了血清对Ｓ期细胞ＴＫ活性、ＴＫ基因表达和ＤＮＡ合成的刺激作用,并促进细胞提前进入Ｓ期．血清刺激Ｇ_０期细胞进入晚Ｇ_１期和Ｓ期时,ＣａＭ水平明显升高,而ＣＢ预处理则使ＣａＭ含量进一步增加,特别是ＣＢ处理促使Ｓ期ＣａＭ增加向核内转移．ＣＢ处理明显增强血清对ｃ－ｊｕｎ、ｃ－ｆｏｓ和ｃ－ｍｙｃ基因表达的刺激作用,而ＰＫＣ抑制剂Ｈ_７则抑制ＣＢ处理对这些基因转录的刺激作用,说明ＣＢ使Ｇ_０期细胞ＭＦ解聚刺激ｃ－ｊｕｎ、ｃ－ｆｏｓ和ｃ－ｍｙｃ的转录活性与ＰＫＣ的作用有关．结果表明Ｇ_０至Ｓ期早期ＭＦ的重组可促进细胞进入Ｓ期,增强ＤＮＡ合成．     

进行性系统性硬化病患者外周血单个核细胞中癌蛋白的表达和NK亚群状况的研究

本文报告了进行性系统性硬化病（ＰＳＳ）患者外周血单个核细胞中Ｃ－ｍｙｃ、Ｋｉ－ｒａｓ和Ｈａ－ｒａｓ三种癌蛋白的表达和ＮＫ细胞亚群的检测结果。与对照相比,ＰＳＳ患者淋巴细胞的Ｃ－ｍｙｃ癌蛋白阳性率显著升高（Ｐ＜０．０１）,单核细胞的阳性率也倾向于明显升高（Ｐ＝０．０５２）;ＰＳＳ组单核细胞的Ｋｉ－ｒａｓ癌蛋白表达显著高于对照组（Ｐ＜０．００１）。另外,ＰＳＳ患者ＮＫ细胞中Ｌｅｕ－１１ｃ~＋亚群细胞数显著低于对照值,而Ｌｅｕ－７＋亚群细胞数则显著高于对照值（Ｐ＜０．０５）。作者结合文献讨论了ＰＳＳ患者体内癌基因表达的可能机制以及癌基因表达和ＮＫ亚群改变的临床意义。     

生长抑素对羟自由基损伤的人胃粘膜上皮细胞系GES—1的影响

目的和方法：采用人胃粘膜上皮细胞系ＧＥＳ１细胞传代培养技术,利用Ｆｅ２＋与Ｈ２Ｏ２反应生成的羟自由基（ｈｙｄｒｏｘｙｌｒａｄｉｃａｌ,ＯＨ·）建立细胞损伤模型,探讨ＯＨ·损伤人胃粘膜细胞的机制,观察生长抑素（ｓｏｍａｔｏｓｔａｔｉｎ,ＳＳ）对ＧＥＳ１细胞抗ＯＨ·损伤的影响。结果：（１）ＯＨ·可直接损伤ＧＥＳ１细胞,表现为细胞存活率下降而细胞乳酸脱氢酶（ｌａｃｔａｔｅｄｅｈｙｄｒｏｇｅｎａｓｅ,ＬＤＨ）漏出量增多;预先在细胞培养液中加入ＯＨ·特异性清除剂二甲基亚砜（５ｍｍｏｌ／Ｌ）,可预防该损伤。预先加入ＳＳ（０．０１ｍｇ／Ｌ,０．１ｍｇ／Ｌ,１．０ｍｇ／Ｌ,１０ｍｇ／Ｌ）对细胞存活率和细胞ＬＤＨ漏出量无影响;（２）加入ＯＨ·后,细胞丙二醛（ＭＤＡ）、氧化型谷胱甘肽（ＧＳＳＧ）含量上升而还原型谷胱甘肽（ＧＳＨ）含量下降。以ＳＳ０．１ｍｇ／Ｌ,１．０ｍｇ／Ｌ,１０ｍｇ／Ｌ预处理,可部分减轻上述改变。结论：ＯＨ·可直接损伤ＧＥＳ１细胞,其机制与破坏细胞的巯基稳态及加重细胞的脂质过氧化程度有关;ＳＳ可通过维持细胞的巯基稳态,部分减轻ＯＨ·所致的ＧＥＳ１细胞脂质过氧化程度。     

天然和氧化修饰型LDL、VLDL及HDL对培养人动脉平滑肌细胞原癌基因fos及myc表达的影响

动脉平滑肌细胞（ＳＭＣ）是动脉粥样硬化（ＡＳ）斑块中的主要细胞,它的增殖在ＡＳ形成过程中极其重要。脂蛋白和氧化修饰型脂蛋白对ＳＭＣ增殖的影响以及ＳＭＣ增殖与原癌基因异常表达的关系是当前ＡＳ发病机制研究的热点之一。我们在建立人主动脉ＳＭＣ体外培养方法的基础上,观察了ＬＤＬ,ＶＬＤＬ及ＨＤＬ和相应的氧化修饰型脂蛋白对培养人ＳＭＣｆｏｓ,ｍｙｃ,ｅｒｂ－Ｂ原癌基因转录表达的影响。结果表明：①ＨＤＬ对ＳＭＣｆｏｓ,ｍｙｃ基因表达无影响;②ＬＤＬ和ＶＬＤＬ有使这些基因表达增加的趋势,但与对照比较差异不显著（Ｐ＞０．０５）;③ＯＸ－ＶＬＤＬ,ＯＸ－ＶＬＤＬ和ＯＸ－ＨＤＬ有使ＳＭＣｆｏｓ,ｍｙｃ基因表达显著增强的作用（Ｐ＜０．０１）,且其作用较相应的天然脂蛋白大（Ｐ＜０．０１）．上述结果说明：ＬＤＬ,ＶＬＤＬ,ＯＸ－ＬＤＬ,ＯＸ－ＶＬＤＬ和０Ｘ－ＨＤＬ的致ＡＳ作用可能与刺激ＳＭＣｆｏｓ和ｍｙｃ癌基因表达增加有关。     

外源性神经节苷脂GM3影响人肝癌细胞生长的可能机制的初步研究

通过苔酚蓝染色细胞发现,外源性ＧＭ３能明显抑制人肝癌细胞株ＳＭＭＣ－７７２１细胞生长,在ＧＭ３处理３ｄ时,出现明显差异,通过ＮｏｒｔｈｅｒｎＢｌｏｔ分析发现,外源性ＧＭ３可明显影响人肝癌细胞株ＳＭＭＣ－７７２１细胞中ｃ－ｆｏｓ、ｃ－ｊｕｎ、ｃ－ｍｙｃ和Ｎ－ｒａｓ四种癌基因的ｍＲＮＡ表达,未经ＧＭ３处理的细胞中没有检测到ｃ－ｆｏｓｍＲＮＡ,但ｃ－ｊｕｎ微量表达,并有ｃ－ｍｙｃ和Ｎ－ｒａｓｍＲＮＡ的高     

毛喉萜抑制人胃癌细胞BGC－823增殖与ras基因表达相关性研究

毛喉萜（ｆｏｒｓｋｏｌｉｎ）对人胄癌细胞ＢＧＣ－８２３增殖有明显抑制作用,具药物剂量和作用时间之依赖性。剂量为２×１０~（－５）ｍｏｌ／Ｌ之毛喉萜使胃癌细胞在软琼脂中形成集落的能力显著降低;癌基因ｃ－Ｈａ－ｒａｓ之表达明显被抑制,细胞核中与ｒａｓ基因上游调控区２．５ｋｂ片段结合的三种蛋白结合能力下降。联系到以同样浓度药物处理胃癌细胞７２ｈ,细胞质、膜与细胞核中蛋白激酶Ｃ（ＰＫＣ）活性均下降的现象,可能ＰＫＣ活性下降与Ｈａ－ｒａｓ基因上游片段２．５ｋｂ结合蛋白之结合能力下降存在相关性,ＰＫＣ可能通过影响ＤＮＡ结合蛋白的磷酸化作用,导致了Ｈａ－ｒａｓ基因表达之被阻抑。而ｒａｓ基因表达下降可能是毛喉萜抑制胃癌细胞增殖的一个重要分子事件。     

人肝细胞癌中N－ras、c－myc癌基因的表达──原位分子杂交和免疫组织化学研究

为了明确Ｎ－ｒａｓ、ｃ－ｍｙｃ癌基因在人肝细胞癌（ＨＣＣ）中的表达及其形态学分布,我们对３８例石蜡包埋的ＨＣＣ（其中３３例带有癌周肝组织）标本进行了原位核酸杂交和免疫组化研究。结果表明,ＨＣＣ及癌周肝组织中Ｎ－ｒａｓ表达阳性率分别为４２％和３９％;ｃ－ｍｙｃｍＲＮＡ阳性表达率分别为４７％和３６％;ｃ－ｍｙｃ蛋白阳性率分别为５３％和３９％。ＨＣＣ与癌周肝之间Ｎ－ｒａｓ、ｃ－ｍｙｃｍＲＮＡ及ｃ－ｍｙｃ蛋白表达水平无显著差别;ｃ－ｍｙｃｍＲＮＡ及蛋白阳性强度也无显著差别,其形态学分布基本一致,主要集中于癌细胞和癌周肝中的部分高度增生结节;Ｎ－ｒａｓ表达增强主要见于癌细胞、癌周肝中的高度增生结节、小细胞性不典型增生及少部分肝小多角细胞。它们与ＨＢｘＡｇ表达之间无明确的对应关系。上述结果显示,ＨＣＣ中Ｎ－ｒａｓ、ｃ－ｍｙｃ表达都显著增强,它们可能是人ＨＣＣ发生中较晚期的事件,而Ｎ－ｒａｓ表达增强早于ｃ－ｍｙｃ癌基因活化。     

外源性神经节苷脂GM_3影响人肝癌细胞生长的可能机制的初步研究

通过苔酚蓝染色细胞发现,外源性GM3（10μg/ml）能明显抑制人肝癌细胞株SMMC-7721细胞生长,在GM3处理3d时,出现明显差异．通过NorthernBlot分析发现,外源性GM3可明显影响人肝癌细胞株SMMC-7721细胞中c-fos、c-jun、c-myc和N-ras这四种癌基因的mRAN表达．未经GM3处理的细胞中没有检测到c-fosmRNA,但c-jun微量表达,并有c-myc和N-rasmRNA的高水平表达而GM3可在短时间内快速大量地诱导c-fos、c-junmRNA的生成．GM3处理的细胞,c-myc和N-rasmRNA的表达均明显减少．GM3处理45min时,c-myc基因表达只为对照组的39．55％;GM3处理24h时,N-ras基因表达为对照组的30.48％．以上结果提示：GM3抑制SMMC-7721细胞生长很可能是通过改变癌基因表达来实现的．     

Oncogene expression in human hepatoma cells PLC/PRF/5

The expression of 7 cellular oncogenes in a human hepatoma cell line PLC/PRF/5 was studied using Northern blot analyses. Among the oncogenes tested, c-abl, c-fes, c-fms, c-myc, c-Ha-ras and c-sis were expressed. The oncogene c-Ki-ras was not expressed. The length of the mRNAs expressed was almost consistent with published data. Compared to the oncogene expression in Daudi lymphoma cells, the same kind of oncogenes were expressed in PLC/PRF/5 cells, but the intensity of the signal in each oncogene expression was stronger in Daudi cells than in PLC/PRF/5 cells. Considering the cellular localization and the function of each oncogene, the oncogene survey in hepatoma cells broadens the knowledge of hepatocarcinogenesis and the character of human hepatoma cells.     

Immortalization by c-myc, H-ras, and Ela oncogenes induces differential cellular gene expression and growth factor responses.

Early-passage rat kidney cells were immortalized or rescued from senescence with three different oncogenes: viral promoter-driven c-myc, H-ras (Val-12), and adenovirus type 5 E1a. The normal c-myc and H-ras (Gly-12) were unable to immortalize cells under similar conditions. Quantitation of RNA in the ras-immortalized lines demonstrated that the H-ras oncogene was expressed at a level equivalent to that of the normal H-ras gene in established human or rat cell lines. Cell lines immortalized by different oncogenes were found to have distinct growth responses to individual growth factors in a short-term assay. E1a-immortalized cells were largely independent of serum growth factors, whereas c-myc-immortalized cells responded to serum better than to epidermal growth factor and insulin. H-ras-immortalized cells responded significantly to insulin alone and gave a maximal response to epidermal growth factor and insulin. Several cellular genes associated with platelet-derived growth factor stimulation, including c-myc, were expressed at high levels in the H-ras-immortalized cells, and c-myc expression was deregulated, suggesting that the H-ras oncogene has provided a "competence" function. H-ras-immortalized cells could not be morphologically transformed by secondary transfection with a long terminal repeat-c-myc oncogene, but secondary transfection of the same cells with H-ras (Val-12) produced morphologically transformed colonies that had 20- to 40-fold higher levels of H-ras oncogene expression. Thus, transformation in this system is dependent on high levels of H-ras oncogene expression rather than on the presence of activated H-ras and c-myc oncogenes in the same cell.     

癌基因及癌发育基因在裸小鼠人肝癌移植瘤中表达

本文采用Northern blot,斑点杂交,western Immunoblot,凝集素亲和电泳及聚丙烯酰胺梯度电泳方法分别检测裸小鼠肝癌移植瘤中C-ras基因簇(N-ras,H-ras及K-ras),甲种胎儿蛋白以及γ谷氨酰转肽酶(GGT)基因及其产物的表达。结果提示C-ras基因簇均有不同程度的表达,其中N-ras基因表达水平要比H-ras高8倍,比K-ras高20倍左右,同样AFP及GGT基因均有较高水平的表达。经ras-p21单克隆抗体检测,发现肝癌组织抽提液中p21呈现阳性反应;AFP亚型分析提示AFP分子变异体属肝癌特异性分子亚型;GGT同Ⅰ酶酶谱分析表明组织中仅合成肝癌特异性GGT同Ⅰ酶酶谱(Ⅰ’,Ⅱ’)。上述结果充分表明癌基因及癌发育基因的高表达可能与癌细胞去分化性,分裂旺盛程度及细胞恶性度相关。最后文内还对裸小鼠人肝癌移植瘤中二类基因的相关性作一定的讨论。     

A diet high in cholesterol and deficient in vitamin E induces lipid peroxidation but does not enhance antioxidant enzyme expression in rat liver

Expression of antioxidant enzymes (AOE), an important mechanism in the protection against oxidative stress, could be modified by the redox status of the cells. The aim of this project was to evaluate the role of vitamin E deficiency in association with a high-cholesterol diet in the hepatic lipid peroxidation and the expression of AOE. Two groups of 6 male rats were fed with a high-cholesterol or a high-cholesterol vitamin E-deficient diet. All animals were sacrificed at 72 days of treatment. Liver lipid peroxidation index (Malondialdehyde; MDA) and hepatic AOE were evaluated. Total liver RNA was extracted, and the steady state messenger RNA (mRNA) levels of glutathion peroxydase, manganese superoxide dismutase, Cu/Zn superoxide dismutase and catalase were examined by northern blot. After 72 days on the diet, a significant increase in the lipid peroxidation index was observed in the vitamin E deficient group (MDA : 4.45 +/- 0.29 nmol/mg protein versus 3.65 +/- 0.1 nmol/mg protein in vitamin E normal group). Despite this oxidative stress, the activities and mRNA levels of liver AOE were not significantly different in the 2 groups. These preliminary results show that chronic vitamin E deficiency associated with high cholesterol diet is able to increase lipid peroxidation without modulation of AOE expression and activity in the liver. This suggests that beneficial effects of dietary vitamin E are due to a plasma antioxidant effect or a cell mediated action, rather than to a specific modulation of cellular enzymes.     

人膀胱癌中某些癌基因的研究

本实验应用Northern和斑点印渍杂交技术探测了人膀胱癌细胞株中c-myc、c-fos、erbB等癌基因的表达,以及TPA对这些癌基因表达的调控,发现BIU-87细胞有这些癌基因的表达,并能被TPA所增强,同时也发现人膀胱癌组织有c-myc、c-fos、erbB、N-ras基因的高表达。提示蛋白激酶C的激活可以诱导某些癌基因的表达。多种癌基因的表达异常可能在膀胱癌中起重要作用。     

Importance of the polyunsaturated fatty acid to vitamin E ratio in the resistance of rat lung microsomes to lipid peroxidation

Rat lung microsomes and liposomes made from isolated lung microsomal lipids were found to be much more resistant to lipid peroxidation than those from liver in both enzymatic and nonenzymatic systems. The polyunsaturated fatty acid (PUFA) content of isolated lung microsomal lipids was 28% of total fatty acids, while liver was 54%. The vitamin E (α-tocopherol) content of isolated lung microsomal lipids was 2.13 nmol/μmol lipid phosphate and that of liver was 0.43. Individually, neither the lower PUFA content nor higher vitamin E levels could account for the resistance of lung microsomal lipids to peroxidation. Distearoyl-L-a-phosphatidylcholine and/or α-tocopherol were added to liver microsomal lipids to achieve different PUFA to vitamin E ratios at PUFA contents of 28% or 54%, and the resulting liposomes were subjected to an NADPH-dependent lipid peroxidation system utilizing cytochrome P450 reductase, EDTA-Fe⁺³, and ADP-Fe⁺³. Liposomes having PUFA to vitamin E ratios less than approximately 250 nmol PUFA/nmol vitamin E were resistant to peroxidation, whereas lipid peroxidation, as evidenced by malondialdehyde production, occurred in liposomes having higher ratios. When lipid peroxidation occurred, 40%–60% of the liposomal vitamin E was irreversibly oxidized. Irreversible oxidation did not occur in the absence of lipid peroxidation. These studies indicated that the low PUFA to vitamin E ratio in lung microsomes and isolated microsomal lipids was sufficient to account for the observed resistance to lipid peroxidation.     

Ras-mediated cell cycle arrest is altered by nuclear oncogenes to induce Schwann cell transformation.

The cellular responses to ras and nuclear oncogenes were investigated in purified populations of rat Schwann cells. v-Ha-ras and SV40 large T cooperate to transform Schwann cells, inducing growth in soft agar and allowing proliferation in the absence of added mitogens. Expression of large T alone reduces their growth factor requirements but is insufficient to induce full transformation. In contrast, expression of v-Ha-ras leads to proliferation arrest in Schwann cells expressing a temperature-sensitive mutant of large T at the restrictive temperature. Cells arrest in either the G1 or G2/M phases of the cell cycle, and can re-enter cell division at the permissive temperature even after prolonged periods at the restrictive conditions. Oncogenic ras proteins also inhibit DNA synthesis when microinjected into Schwann cells. Adenovirus E1a and c-myc oncogenes behave similarly to SV40 large T. They cooperate with Ha-ras oncogenes to transform Schwann cells, and prevent ras-induced growth arrest. Thus nuclear oncogenes fundamentally alter the response of Schwann cells to a ras oncogene from cell cycle arrest to transformation.     

CWE纯系小鼠脑组织发育过程中细胞癌基因及其表达研究

 本文以Ha-ras.c-fos、c-myc、v-erbB、mos五种癌基因片段为分子探针,应用斑点杂交技术,对CWE纯系小鼠脑组织发育的四个时期(胚胎期、新生期、性成熟期、体成熟期)的RNA进行分子杂交分析。发现:在实验各期中这几种癌基因的表达有较明显的变化。Ha-ras、c-fos、c-myc基因的表达在胚胎期和新生期脑组织中较高;v-erbB基因的表达在性成熟期脑组织中较高;mos基因在实验各期均无表达。DNA斑点杂交结果:小鼠脑组织发育各期均未观察到癌基因扩增现象。Southern杂交结果:CWE小鼠发育的各期均显示:5.4kb、3.4kb、1.8kb、1.0kb四条c-fos基因区带;7.4kb、4.5kb、3.4kb三条c-myc基因区带。结果表明:不同细胞癌基因在小鼠胚胎发育和胚后发育中有不同的表达。