PI3K和MAPK信号通路对A549细胞FOXO1蛋白表达及其亚细胞定位的调节

目的探讨非小细胞肺癌中磷脂酰肌醇-3-激酶(PI3K)/AKT和丝裂原活化蛋白激酶MAPK/ERK信号通路对Forkhead转录因子(Fox蛋白家族)FOXO1活性的影响及分子机制。方法体外培养人非小细胞肺癌系A549,分别选用PI3K/AKT信号通路特异性抑制剂LY294002和MAPK/ERK信号通路特异性抑制剂UO126及两种抑制剂联合处理细胞之后,MTT比色法检测其对细胞增殖的影响;Western blot检测蛋白FOXO1、p-FOXO1及信号下游蛋白Bim表达的变化;免疫荧光法检测FOXO1蛋白在A549细胞中亚细胞的定位的变化。结果与对照组相比,LY294002和UO126都能明显地抑制A549细胞的增殖,且具有时间依赖性。Western blot结果显示,FOXO1的蛋白水平未见显著性变化,而FOXO1的磷酸化水平明显下降,Bim的表达相应增加。免疫荧光结果显示,FOXO1在A549细胞中的核转位增多。LY294002和UO126联合处理A549细胞时,较药物单独作用效果明显增加。结论 PI3K/AKT和MAPK/ERK信号通路能调节FOXO1磷酸化水平,且具有协同作用,抑制其转录活性。FOXO1通过激活Bim蛋白,促进细胞凋亡,抑制细胞的增殖。     

MNNG诱导TERC基因沉默的16HBE细胞恶性转化模型的建立

目的: 建立N-甲基em>N’-硝基-N-亚硝基胍(N-methyl-N-nitro-N-nitrosoguanidine, MNNG)诱导的人端粒酶RNA组分(telomerase RNA component, TERC)缺陷的人支气管上皮细胞株(16HBE)恶性转化细胞模型。方法:将靶向TERC基因的shRNA干扰质粒载体转染16HBE细胞,G418抗性克隆筛选得到稳定转染的16HBE-1细胞,RT-PCR检测16HBE-1细胞TERC mRNA的干扰效率;用1 mg/L MNNG对16HBE-1细胞进行隔代染毒,每次染毒1 h;直到染毒27次转化灶的出现。分离扩增转化灶细胞并命名为16HBE-T,用软琼脂克隆形成实验和裸鼠成瘤实验鉴定细胞的转化程度。结果:从转化灶分离培养的细胞能在软琼脂中生长,且转化细胞能在裸鼠体内成瘤,HE染色后光镜下显示为鳞癌。结论:成功建立MNNG诱导的TERC基因缺陷的16HBE细胞恶性转化模型。     

FOXO1质粒稳定转染人骨肉瘤细胞的筛选及意义

目的 建立稳定表达FOXO1-GFP的人骨肉瘤U2OS细胞系,并验证U2OS-FOXO1-GFP细胞模型对氧化应激损伤的指示作用.方法 将pcDNA3-GFP-FOXO1质粒转染到U2OS细胞中,利用G418和FCM筛选稳定细胞系.40mmol/LAAPH处理U2OS-FOXO1-GFP细胞4h,CCK-8检测细胞活力,荧光显微镜观察FOXO1-GFP的分布情况.结果 成功获得U2OS-FOXO1-GFP稳转细胞系.经G418和FCM筛选后,FOXO1-GFP阳性细胞占细胞总数的92％.CCK-8结果显示,AAPH处理后,U2OS-FOXO1-GFP细胞存活率下降至0.55 ±0.04明显低于对照组(P＜0.05).荧光显微镜观察发现,正常情况下,FOXO1-GFP位于细胞质;AAPH处理后,FOXO1-GFP易位到细胞核.结论 U2OS-FOXO1-GFP细胞系能很好的指示细胞氧化应激损伤,为筛选抗氧化应激药物提供了一种有利工具.     

豨莶草调控sirt1/FOXO1通路对膝骨关节炎大鼠软骨损伤的影响

目的:探讨豨莶草调控sirt1/FOXO1通路对膝骨关节炎大鼠软骨损伤的影响。方法:SD大鼠随机分组为对照组、模型组、豨莶草（2 g/kg）组、尼克酰胺（NA,sirt1抑制剂,剂量:100 mg/kg）组、豨莶草+尼克酰胺组（豨莶草为2 g/kg,NA为100 mg/kg）。除对照组外,其余各组以改良伸直位固定法建立膝骨关节炎大鼠模型,按组别分别以药物处理后,测量各组大鼠膝关节宽度、被动活动度;检测各组大鼠压痛阈值、热痛阈值;以苏木精-伊红染色（HE）观察各组大鼠膝关节软骨病理损伤情况,进行Mankin′s评分;以酶联免疫吸附（ELISA）试剂盒检测各组大鼠血清中IL-1β、肿瘤坏死因子（TNF-α）、软骨寡聚基质蛋白（COMP）水平;以蛋白免疫印迹法检测各组大鼠膝关节软骨组织sirt1、FOXO1、acely-FOXO1蛋白表达。结果:与对照组相比,模型组大鼠膝关节宽度、Mankin′s评分、血清中IL-1β、TNF-α及COMP水平、膝关节软骨组织中acely-FOXO1升高（P<0.05）,膝关节被动活动度、压痛阈值、热痛阈值、膝关节软骨组织中sirt1蛋白表达降低（P<0.05）。与模型组相比,豨莶草组大鼠膝关节宽度、Mankin′s评分、血清中IL-1β、TNF-α及COMP水平、膝关节软骨组织中acely-FOXO1降低（P<0.05）,膝关节被动活动度、压痛阈值、热痛阈值、膝关节软骨组织中sirt1蛋白表达升高（P<0.05）;NA组大鼠膝关节宽度、Mankin′s评分、血清中IL-1β、TNF-α及COMP水平、膝关节软骨组织中acely-FOXO1升高（P<0.05）,膝关节被动活动度、压痛阈值、热痛阈值、膝关节软骨组织中sirt1蛋白表达降低（P<0.05）。与豨莶草组相比,豨莶草+NA组大鼠膝关节宽度、Mankin′s评分、血清中IL-1β、TNF-α及COMP水平、膝关节软骨组织中acely-FOXO1升高（P<0.05）,膝关节被动活动度、压痛阈值、热痛阈值、膝关节软骨组织中sirt1蛋白表达降低（P<0.05）。与NA组相比,豨莶草+NA组大鼠膝关节宽度、Mankin′s评分、血清中IL-1β、TNF-α及COMP水平、膝关节软骨组织中acely-FOXO1降低（P<0.05）,膝关节被动活动度、压痛阈值、热痛阈值、膝关节软骨组织中sirt1蛋白表达升高（P<0.05）。结论:豨莶草可通过上调sirt1表达,下调FOXO1乙酰化水平,减轻膝骨关节炎大鼠软骨损伤。     

用高通量实时荧光PCR技术研究低浓度MNNG诱发的细胞基因应答反应

目的：研究低浓度N-甲基-N'-硝基-N-甲基亚硝基胍对人羊膜FL细胞部分基因表达的影响,以助于阐明MNNG引起细胞应答反应的基因及其调控机制。方法：用ABI公司的高通量实时荧光定量PCR方法,检测FL细胞在0.2μmol/LMNNG处理后基因表达发生的改变。数据用ABI公司的SDS2.1软件分析。结果：MNNG处理后,在检测的95个基因中,29个基因表达发生改变,其中14个基因下调2倍以上,15个基因下调在1.5-2倍之间;其中有4个基因与细胞周期相关,6个基因与信号转导相关,6个基因与转录调节相关。结论：在低浓度MNNG攻击后,FL细胞的基因表达发生了显著的变化。     

MCPH1在电离辐射诱导食管癌细胞DNA损伤通路中的作用

目的:研究MCPH1在电离辐射诱导食管癌细胞DNA损伤通路中的作用。方法:应用已构建的沉默MDC1的食管癌ECA109细胞株接受8Gy电离辐射后1h,检测相关因子核内斑点形成情况。构建沉默MCPH1的食管癌ECA109细胞株,检测此细胞株接受同样照射条件后相关因子核内斑点的形成情况。结果:成功构建沉默MCPH1的食管癌ECA109细胞;电离辐射使MDC1、MCPH1与γ-H2AX蛋白相互作用。沉默MDC1不影响γ-H2AX和MCPH1核内斑点的形成;沉默MCPH1使电离辐射导致的MDC1核内斑点减少,不影响γ-H2AX核内斑点的形成。结论:MCPH1在电离辐射诱导的DNA损伤通路中可能位于H2AX下游、MDC1上游,可以调控MDC1核内斑点形成。     

VDT低频脉冲磁场对MNNG诱致DNA损伤的影响

用视频显示终端（ＶＤＴ）产生的磁通密度峰值为４μＴ和４０μＴ，频率为１５．６ｋＨｚ低频脉冲磁场和甲基硝基亚硝酸胍（ＭＮＮＧ，已知可损伤ＤＮＡ的致癌剂）对培养的人羊膜细胞进行７２ｈ的辐射及接触，结果得出４０μＴ低频脉冲磁场辐射能增加ＭＮＮＧ引起的细胞３Ｈ／１４Ｃ放射活性比值；４μＴ低频脉冲磁场辐射则不能增加其放射活性比值，表明了ＶＤＴ低频脉冲磁场的磁通密度峰值在４０μＴ的情况下，能增强ＭＮＮＧ对细胞ＤＮＡ的损伤作用     

甲基硝基亚硝胍处理的vero细胞中磷酸化蛋白的差异显示

目的：初步了解哺乳类细胞非定标性突变形成是否与以蛋白质磷酸化级联反应为主要形式的细胞信号传导通路有关;方法：采用［３２Ｐ］体内预标记及凝胶双向电泳方法差异显示甲基硝基亚硝胍（ＭＮＮＧ）处理组和对照组磷酸化蛋白,蛋白质免疫印迹杂交试验初步鉴定差异显示蛋白斑点性质;结果：在处理组发现两个与对照组不同的蛋白斑点,分子量分别在６８×１０３和４３×１０３附近,与抗酪氨酸磷酸化蛋白抗体未发生阳性反应;结论：根据差异显示蛋白斑点的分子量和印迹杂交试验结果,初步认为所见蛋白斑点可能为丝／苏氨酸磷酸化蛋白,且可能为丝裂原激活的蛋白激酶（ＭＡＰＫ）成员     

转录因子FOXO1对胰岛β细胞致炎因子产生的影响

目的观察转录因子FOXO1(forkhead box O1)对胰岛β细胞炎症因子产生的影响,探讨转录因子FOXO1在糖尿病发病机制中的作用。方法运用脂质体转染方法,将pcDNA-FOXO1真核表达载体瞬时转染至NIT-1细胞,通过Western blot检测细胞中FOXO1的过表达情况;以LPS分别处理重组质粒(pcDNA-FOXO1)、空质粒(pcDNA3.1)转染以及未转染的NIT-1细胞24 h后,应用ELISA法检测3组细胞致炎因子IL-1β、TNF-α表达情况。以LPS和PBS分别处理NIT-1细胞24 h后,ELISA测定两组细胞致炎因子IL-1β、TNF-α表达情况,Western blot比较两组细胞FOXO1蛋白表达及磷酸化水平的差异。结果 FOXO1在瞬时转染48 h的NIT-1细胞中实现了过表达;经LPS刺激后,重组质粒转染的NIT-1细胞产生的IL-1β和TNF-α显著高于空质粒转染和未转染组(P<0.01);经LPS处理24 h后的NIT-1细胞产生了致炎因子IL-1β和TNF-α,而PBS处理组未见表达。LPS处理组中FOXO1蛋白表达高于PBS处理组,但磷酸化水平显著低于PBS处理组(P<0.01)。结论炎症状态下,过表达转录因子FOXO1可增加胰岛β细胞致炎因子的产生,这主要与非磷酸化FOXO1的相对增多有关,它有望成为糖尿病抗炎治疗的新靶点。     

Dna damage in human mononuclear cells induced by bacterial endotoxin

Damage to nuclear DNA in human peripheral blood mononuclear cells was studied after in vitro treatment with bacterial endotoxin by alkaline comet assay. It was found that LPS induced DNA damage as soon as over the first 30 min of incubation, while by the 4th hour of incubation DNA damage was found in more than 95% cells. Exogenous superoxide dismutase completely protected DNA, which suggests that superoxide radical is the primary extracellular damaging agent. Polyphenol antioxidant (water-soluble lignin) and specific NADPH oxidase inhibitor (diphenyleneiodonium chloride) also produced a protective effect. Our results show that LPS-activated mononuclear cells can be used ex vivo as a convenient and adequate experimental system for evaluation of the efficiency of various substances in protection of lymphocyte DNA from the damaging effect of reactive oxygen species of LPS-stimulated monocytes. Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 146, No. 9, pp. 275–277, September, 2008     

非小细胞肺癌中Bmi-1和WWOX蛋白的表达及其临床意义

目的探讨非小细胞肺癌中BMi-1与WWOX蛋白的表达及其临床意义。方法应用免疫组化和Western blot检测86例非小细胞肺癌中Bmi-1蛋白和WWOX蛋白的表达水平,分析BMi-1与WWOX蛋白与临床患者特征的关系,并对患者生存影响因素进行分析。结果 Bmi-1蛋白在非小细胞肺癌中的表达水平显著高于癌旁正常组织中表达水平(0.01),而WWOX蛋白在非小细胞肺癌中的表达水平(0.52±0.05)则显著低于癌旁正常组织中表达水平(0.01)。Bmi-1和WWOX蛋白表达水平均与淋巴结转移有关(0.05)。结论 Bmi-1的高表达和WWOX蛋白的低表达均与淋巴结转移有关。     

Cardiac troponin I is abnormally expressed in non-small cell lung cancer tissues and human cancer cells

Cardiac troponin I (cTnI) is the only sarcomeric protein identified to date that is expressed exclusively in cardiac muscle. Its expression in cancer tissues has not been reported. Herein, we examined cTnI expression in non-small cell lung cancer (NSCLC) tissues, human adenocarcinoma cells SPCA-1 (lung) and BGC 823 (gastric) by immunohistochemistry, western blot analysis and real-time PCR. Immunopositivity for cTnI was demonstrated in 69.4% (34/49) NSCLC tissues evaluated, and was strong intensity in 35.3% (6/17) lung squamous cell carcinoma cases. The non-cancer-bearing lung tissues except tuberculosis (9/9, 100%) showed negative staining for cTnI. Seven monoclonal antibodies (mAbs) against human cTnI were applied in immunofluorescence. The result showed that the staining pattern within SPCA-1 and BGC 823 was dependent on the epitope of the cTnI mAbs. The membrane and nucleus of cancer cells were stained by mAbs against N-terminal peptides of cTnI, and cytoplasm was stained by mAbs against the middle and C-terminal peptides of cTnI. A ~25 kD band was identified by anti-cTnI mAb in SPCA-1 and BGC 823 extracts by western blot, as well as in cardiomyocyte extracts. The cTnI mRNA expressions in SPCA-1 and BGC 823 cells were about ten thousand times less than that in cardiomyocytes. Our study shows for the first time that cTnI protein and mRNA were abnormally expressed in NSCLC tissues, SPCA-1 and BGC 823 cells. These findings challenge the conventional view of cTnI as a cardiac-specific protein, enabling the potential use of cTnI as a diagnostic marker or targeted therapy for cancer.     

DNA damage and repair induced by bleomycin in mammalian and insect cells.

We assessed the response of mosquito (ATC-15) and mammalian (CHO) cells to bleomycin (BLM). Comparison of the data obtained in both cell lines indicates that DNA in the chromatin of mosquito cells is 10 to 20 times more resistant to BLM, and that the DNA damage induced by this antibiotic is better repaired in mosquito than in mammalian cells. Permeability of the cell membrane for BLM was found to be the same for both cell lines. Moreover, the time-kinetics of BLM damage to nuclear DNA was similar for ATC-15 and CHO cells. The low sensitivity of mosquito cells to BLM is reflected in better growth efficiency. These cells exhibit a satisfactory growth at BLM doses that produce a permanent arrest of growth in CHO cells. It is proposed that variations in the chromatin structure and in the intracellular free amino acid pool may play an important role in the differential response of insect and mammalian cells to BLM.     

The apoptosis of non-small cell lung cancer induced by cisplatin through modulation of STIM1

Cis-diamminedichloroplatinum (II) (cisplatin) is one of the most active antitumor agents used in human chemotherapy of non-small cell lung cancer. Cisplatin forms crosslinked DNA adducts and its cytotoxicity has been shown to be mediated by propagation of DNA damage recognition signals to downstream pathways prompting apoptosis. The steps involved in the process include changes in Ca²⁺ signaling with dysregulated tumor cell turn-over. Stromal interaction molecules 1 (STIM1), as one of the most potent tumor suppressor genes, are identified as the endoplasmic-reticulum (ER) Ca²⁺ sensor controlling store-operated Ca²⁺ entry (SOCE) in non-excitable cells, which is main pathway to extracellular Ca²⁺ influx. Its role in STIM1 cisplatin-induced apoptosis of non-small cell lung cancer was the focus of study with focus on SOCE inhibitors 2-APB- and SKF96365-cisplatin-induced apoptosis in the non-small cell lung cancer (NSCLC) cell lines A549 and H460. In this experimental model, cisplatin-induced apoptosis and decreased concentration of intracellular Ca²⁺ was demonstrated. The expression of STIM1 was significantly higher in carcinoma tissue than in the adjacent non-neoplastic lung tissue. These findings support the conclusion that STIM1 may play an important role in the development of NSCLC which makes drugs that repress the expression of STIM1 to be a potential target for lung cancer therapy.     

肺癌中HDPR1的表达下调与肺癌的恶性程度相关

目的研究HDPR1(human homologue of Dapper)在人非小细胞肺癌的表达,分析其表达与p120ctn和β-catenin表达是否相关,及其与肺癌恶性程度的关系。方法应用免疫组织化学染色检测120例非小细胞肺癌石蜡标本,应用WesternBlot和RT-PCR检测了42例新鲜组织标本中HDPR1、β-catenin和pl20ctn表达的关系,分析它们的表达与临床病理因素之间的相关性。结果 HDPR1在正常肺组织中为高表达,而在非小细胞中有68.3%(82/120)为表达下调,其表达下调不仅与肺癌高TNM分期、低分化、淋巴结转移和不良预后显著相关,并且与肺癌组织中p120ctn的表达下调呈正相关,与β-catenin的表达上调呈负相关。42例新鲜肺癌组织中,HDPR1和p120ctn的蛋白和mRNA均较癌旁正常组织显著下调(<0.05,n=42),然而,β-catenin蛋白在肺癌组织中却普遍表达上调(<0.05,n=42)。结论肺癌中HDPR1的表达下调与p120ctn和β-catenin异常表达相关,与患者的临床病理因素和不良预后明显相关。     

Differential expression and subcellular localization of Prohibitin 1 are related to tumorigenesis and progression of non-small cell lung cancer

Lung cancer remains the leading cause of cancer-related deaths worldwide and non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancer. With a variety of biological functions, Prohibitin1 (PHB1) has been proved tumor-associated. But there are conflicting data regarding the involvement of PHB1 in tumorigenesis and few studies regarding the role of PHB1 in lung cancer. The studies reported herein used a combination of clinical observations and molecular methods to investigate the possible role of PHB1 in NSCLC tissues and cell lines. PHB1 expression was evaluated by RT-PCR, RT-qPCR, Western blotting and immunohistochemistry analysis. Flow cytometric analysis was used to determine the surface expression profiles of PHB1 in lung cell lines. The results showed that PHB1 expression were generally increased in lung cancer tissues when compared with matched noncancerous tissues and closely related with tumor differentiation and lymph node invasion. PHB1 expression levels was also increased in three lung cancer cell lines (SK-MES-1, NCI-H157 and NCI-H292) as compared with BEAS-2B cells. Moreover, there were various subcellular localization of PHB1 in different lung cancer cells and the presence of PHB1 on the surface of lung cancer cells was significantly reduced. In conclusion, PHB1 expression is increased in NSCLC and the up-regulation of PHB1 is associated with clinically aggressive phenotype. The different subcellular localization of PHB1 in NSCLC cells and the loss of the membrane-associated PHB1 probably related to the tumorigenesis and progression of NSCLC and suggests that PHB1 may play different roles in various types of NSCLC.