甲状腺激素缺乏对大鼠胸腺CK19阳性上皮细胞的影响

目的探讨甲状腺激素缺乏对大鼠胸腺CK19^ 上皮细胞的影响。方法将断乳1月龄的Wistar大鼠分为2组：正常组饲以正常饲料，饮用自来水；低碘组饲以低碘饲料，饮用去离子水。实验3个月及6个月后，测定各组大鼠的胸腺指数、血清甲状腺激素及胸腺CK19^ 上皮细胞的体密度和面数密度。结果实验3个月后，低碘组大鼠的胸腺指数、T4显著降低，而CK19^ 上皮细胞的体密度和面数密度未见明显变化；实验6个月后，低碘组大鼠的T3、T4显著降低，胸腺CK19^ 上皮细胞的体密度的面数密度显著降低。结论甲状腺激素缺乏可使大鼠胸腺严重退化，CK19^ 上皮细胞减少。     

低碘大鼠胸腺上皮细胞的异质性研究

目的 探讨胸腺上皮细胞的异质性及甲状腺功能降低时大鼠胸腺上皮细胞的变化。方法 将断乳后1月的Wistar大鼠分为2组：正常组饲以正常饲料，饮用自来水；低碘组饲以低碘饲料，饮用去离子水。饲养3个月后测定各组大鼠血清甲状腺素及胸腺指数，同时对大鼠胸腺进行透射电镜观察。结果 低碘组大鼠血清甲状腺激素及胸腺指数显著降低。胸腺上皮细胞发生了3种变化：(1)细胞角蛋白增多；(2)囊泡增大和(或)小泡增多；(3)细胞降解。结论 不同部位的胸腺上皮细胞对甲状腺功能低下的反应不同。     

MZ3 can induce G2/M-phase arrest and apoptosis in human leukemia cells

Purpose  4-(4-Bromopheny1)-2,3-dihydro-N,3-bis(3,4,5-trimethoxyphenyl)-2-oxoidmi-dazole-1-carboxamide (MZ3) is one of the novel synthesized Combretastatin A-4 analogs. In previous research, we found that MZ3 is a potent and specific compound against leukemia cell lines both in vitro and in vivo. In this paper, our purpose is to investigate the mechanisms of MZ3 induced cell cycle arrest and apoptosis in K562 cells. Methods  Cytotoxicity was measured by MTT method; apoptosis and cell cycle arrest were measured by flow cytometry. DNA fragmentation was tested by agarose gel electrophoresis. Protein expression was analyzed by western blotting. The polymerization of microtubules in cell was detected through immunofluorescence. Results  MZ3 increases cyclin B1 levels and decreases the expression of cdc2, cdc25C and activation of Wee1. The changes in cdc2, cdc25C and Wee1 coincide with the appearance of phosphoepitopes recognized by a marker of mitosis, MPM-2. MZ3 induces apoptosis in K562 cells, proved by condensed DNA (DAPI stain) and DNA ladder. This apoptosis is related with the activation of caspase-9, caspase-3 and PARP cleavage, both of which are at the downstream of mitochondria. The changes of protein expression of Bcl-2 and Bax confirm the causal relationship between MZ3 and mitochondrial pathway, and the downregulation of AKT, p-AKT and XIAP indicate that the AKT pathway may participate in regulating this apoptosis. Moreover, MZ3 can reduce the soluble tubulin in K562 cells and inhibit microtubule assembly. Conclusions  MZ3 is a promising antileukemia compound with antimitotic and apoptotic activity that has potential for management of various leukemias.     

雷公藤内酯醇对人肾小管上皮细胞抗原呈递功能的影响

目的：观察雷公藤内酯醇对炎症因子刺激下人肾近端小管上皮细胞（HKC细胞）抗原呈递能力和共刺激分子表达的影响。方法：以IFN－γ（200μg/L)和TNF－α（20μg/L)联合刺激HKC细胞或同时加入不同浓度的雷公藤内酯醇,采用流式细胞仪检测细胞表面主要组织相容性二类复合体（MHC－Ⅱ）,共刺激分子B7－1,B7－2及细胞间粘附分子1（ICAM－1）表达情况,细胞内ICAM－1mRNA 表达量采用半定量逆转录PCR法检测。结果：普能培养时HKC细胞低度表达MHC－II分子,大量表达ICAM－1分子,不表达B7－1和B7－2分子,IFN－γ（200μg/L)和TNF－α（20μg/L)联合刺激24h后,小管细胞表面MHC－Ⅱ,ICAM－1,B7分子表达均显著增强,其中MHC－Ⅱ变化最大,RTPCR显示ICAM－1 mRNA表达也明显增加,雷公藤内酯醇可以剂理依赖性地抑制炎症因子引起的细胞MHC－Ⅱ,B7－1以及B7－2分子表达上调,但对刺激引起的ICAM－1蛋白及mRNA表达上调无明显影响。结论：雷公藤内酯醇可以抑制炎症因子刺激下人肾近端小管上皮细胞MHC－Ⅱ及B7分子表达上调,减弱肾小管上皮细胞作为抗原呈递细胞活化T细胞的能力。     

Bile salts inhibit growth and induce apoptosis of culture human normal esophageal mucosal epithelial cells

AIM: To investigate the effect of six bile salts: glycocholate (GC), glycochenodeoxycholate (GCDC), glycodeoxycholate (GDC), taurocholate (TC), taurochenodeoxycholate (TCDC), taurodeoxycholate (TDC), and their mixture on cultured human normal esophageal mucosal epithelial cells. METHODS: Human normal esophageal mucosal epithelial cells were cultured with serum-free keratinocyte medium. 3-[4,5-Dimethylthiaolyl]-2,5-diphenyl-tetrazolium bromide assay was applied to the detection of cell proliferation. Apoptotic morphology was observed by phase-contrast video microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Sub-G1 DNA fragmentations and early apoptotic cells were assayed by flow cytometry (FCM) with propidium iodide (PI) staining and annexin V-FITC conjugated with PI staining. Apoptotic DNA ladders on agarose gel electrophoresis were observed. RESULTS: Except for GC, GCDC, GDC, TC, TCDC, TDC and their mixture could initiate growth inhibition of esophageal mucosal epithelial cells in a dose- and time-dependent manner. TUNEL and FCM assays demonstrated that the bile salts at 500 μmol/L and their mixture at 1 500 μmol/L induced apoptosis except for GC. The percentage of sub-G1 detected by FCM with PI staining was 83.5% in cells treated with 500 μmol/L TC for 2 h, and 19.8%, 20.4%, 25.6%, 13.5%, and 75.8% in cells treated with 500 μmol/L GCDC, TCDC, GDC, TDC, and 1 500 μmol/L mixture for 24 h, respectively, which were higher than that of the control (1.5%). The percentage was 1.4% in cells with 500 μmol/L GC for 24 h. DNA ladders on agarose gel electrophoresis were seen in cells treated with 500 μmol/L TC for 2 h and 1 500 μmol/L mixture for 24 h. CONCLUSION: All GCDC, GDC, TC, TCDC, TDC and their mixture can inhibit growth and induce apoptosis of cultured human normal esophageal mucosal epithelial cells, but GC is well tolerated by the cells.     

Characteristics of age-related changes in rat thymus: morphometric analysis and epithelial cell network in various thymic compartments

Structural alterations in thymuses of female rats during the first 2 years of life were evaluated by morphometric analysis and, then, correlated with organization of epithelial cells in various thymic compartments, examined for their cytokeratin immunoreactivity. With an advancing age, the thymuses demonstrated morphological modifications related to maturation and senescence, the dynamics of which varied between particular thymic compartments, and involved subpopulations of thymic epithelial cells. In the entire period of life the most dynamic changes were found in the cortex while the medulla was demonstrated to be a rather “stable” region. Morphometric studies revealed a negative correlation between the volume of thymic cortex and medulla and age of rats and a linear, positive relationship between the volume of connective tissue compartment and age. Changes in organization of epithelial network in the medulla preceded those observed in the cortex. Decreased proliferative activity of subset of medullary cells, which probably represented a self-renewable population, was accompanied by alterations in the immunocytochemically characterized (cytokeratines) differentiation process. At the same period of life, hypertrophy and hyperplasia of superficial epithelial cells seems to functionally replace medullary cells. This process begins around 3rd month of life and expands on all thymic compartments. The first changes in the cortex appeared around 8th month and were connected with reduced cytokeratin immunoreactivity. The involution observed in older animals was preceded by age-related alterations in epithelial network pattern which, in the course of stable morphometric parameters (between 5th and 12th month), showed character of a structural and functional adaptation.     

肠道病毒71型感染UT-SCC-60A对细胞周期阻滞和细胞凋亡发生的研究

目的研究肠道病毒71型感染人扁桃体上皮细胞UT-SCC-60A后对细胞周期阻滞和细胞凋亡发生情况。方法以人扁桃体上皮细胞UT-SCC-60A为细胞模型,CCK8试剂盒和流式细胞仪检测Ev71感染UT-SCC-60A后细胞增殖抑制率、凋亡发生和细胞周期阻滞情况。结果EV71对UT-SCC-60A呈现感染时间依赖性抑制,感染48h后抑制率达92.6%;不同剂量的EV71感染均能够显著抑制UT-SCC-60A增殖。EV71感染使UT-SCC-60A以剂量依赖性发生以早期凋亡为主的细胞凋亡,EV71以感染复数为0.5和1感染12h后,早期凋亡细胞比例分别为21.4%和27.1%。EV71感染UT-SCC-60A后使细胞周期阻滞在S期且G0/G1比例下降,EV71以感染复数为1感染12h后,S期比例由对照组的19.0%上升至31.1%,G0/G1期比例由59.8%下降至45.9%。结论Ev71通过使UT-SCC-60A发生S期阻滞来抑制细胞增殖且诱导以早期凋亡为主的细胞凋亡。     

脂联素对子宫内膜癌细胞生长抑制和细胞凋亡的影响

观察脂联素对子宫内膜癌细胞株HEC-1-A和RL95-2细胞计数、细胞凋亡和细胞周期的影响,检测脂联素对细胞p-AMPK/AMPKα表达的影响.结果提示脂联素对子宫内膜癌细胞具有抑制生长和诱导细胞凋亡发生的作用,其作用机制可能与AMPK激活有关.     

急性肺损伤肺泡上皮细胞凋亡机制研究进展

肺泡上皮细胞是肺脏结构和功能的基础.在生理和病理条件下,肺泡上皮细胞凋亡都具有重要作用.急性肺损伤时肺泡上皮细胞凋亡,肺组织严重破坏,呼吸功能严重受损.近年来相关研究提示,以肺泡上皮细胞凋亡通路为调节靶点,则有可能控制急性肺损伤的程度和范围.     

Monensin-mediated growth inhibition in human lymphoma cells through cell cycle arrest and apoptosis

Monensin, a Na+ ionophore, regulates many cellular functions, including apoptosis. We investigated the in vitro antiproliferative effect of monensin on nine human lymphoma cell lines. Monensin significantly inhibited the proliferation of all the lymphoma cell lines examined with a 50% inhibition concentration of about 0.5 micromol/l, and induced a G1 and/or a G2-M phase arrest in these cell lines. To address the antiproliferative mechanism of monensin, we examined the effect of this drug on cell-cycle-related proteins in CA46 cells (both G1 and G2 arrest) and Molt-4 cells (G2 arrest). Treatment with monensin for 72 h decreased CDK4 and cyclin A levels in CA46 cells, and cdc2 levels in Molt-4 cells. In monensin-treated CA46 cells, increased p21-CDK2, p27-CDK2 and p27-CDK4 complex forms were observed. And, in monensin-treated Molt-4 cells, increased p21-cdc2 complex form was detected. Furthermore, the activities of CDK2- and CDK4-associated kinases were reduced in association with Rb hypophosphorylation in monensin-treated CA46 cells. The activity of cdc2-associated kinase was decreased in both cell lines, which was accompanied by induction of Wee1. Also, monensin induced apoptosis in these cell lines, as evidenced by annexin V binding assay and flow cytometric detection of sub-G1 DNA content. This apoptotic process was associated with loss of mitochondria transmembrane potential (Delta(psi)m). Taken together, these results demonstrated for the first time that monensin potently inhibits the proliferation of human lymphoma cell lines via cell cycle arrest and apoptosis.     

Meconium exposure dependent cell death and apoptosis in human alveolar epithelial cells

Alveolar epithelial cells of neonates are directly exposed to aspirated meconium during meconium aspiration syndrome (MAS). This study was designed to investigate the influence of quantity and time of meconium exposure on the cell viability and caspase activity in type II human alveolar epithelial cells. Human alveolar epithelial cells were incubated with human meconium suspension at different concentrations and for different times. Cell viability and DNA fragmentation were investigated together with caspases activity and the amount of Bcl‐2 protein present. We found that cell viability was significantly lower in cells exposed to a higher concentration of meconium. This was also true for cells exposed to meconium for longer. Significantly higher DNA fragmentation, an approximately two‐ to fivefold increase, was observed in cells that had been exposed to higher (5% and 10%) concentration of meconium compared to those treated with lower (0.1% and 1%) concentrations (P < 0.05). The activity of most apoptotic initiators (caspase 2, 8, 9, 10) and effectors (caspase 3, 6) were found to be significantly higher in cells subject to greater meconium exposure compared to cells with no or minor meconium exposure. The level of Bcl‐2 was also found to be significantly decreased in meconium‐exposed cells (P < 0.05). In conclusion, human meconium would seem to induce direct cell death as well as caspase‐dependent apoptosis in alveolar epithelial cells; the amount and period of exposure to meconium are crucial factors in this process. Thus, removing aspirated meconium should alleviate lung cell damage in neonates and improve the outcome with MAS. Pediatr. Pulmonol. 2010; 45:816–823. © 2010 Wiley‐Liss, Inc.     

低氧条件刺激胃上皮细胞株GES-1后MICA表达研究

目的研究低氧对体外培养胃上皮细胞株GES-1中MHC-Ⅰ类链相关蛋白A（MICA）基因表达的影响。方法建立GES-1细胞体外低氧培养模型,免疫细胞化学技术分别检测MICA在缺氧处理0、24、72 h后的蛋白表达。结果免疫细胞化学证实MICA蛋白的表达随着缺氧时间的增加呈时间效应关系,且表达量随缺氧时间而升高（P〈0.05）。结论低氧可以显著增加胃上皮细胞株GES-1中MICA的表达。     

蛙皮素对人胃黏膜上皮永生细胞系GES-1细胞生长作用和机制的研究

目的　观察蛙皮素对人永生细胞系 (GES 1)生长的调节和作用机制。方法　①分子水平观察GES 1细胞胃泌素释放肽 (GRP)受体mRNA的表达。②利用受体化学交联和细胞膜组织化学法观察GRP受体蛋白表达。③观察不同浓度的蛙皮素及其受体拮抗剂对GES 1细胞生长的影响。④观察蛋白激酶C (PKC)抑制剂对蛙皮素促进GES 1细胞作用的影响。⑤观察蛙皮素作用GES 1细胞后 ,细胞内三磷酸肌醇 (IP3 )和PKC活性以及观察蛙皮素对此细胞系作用后GRP受体mRNA表达量的变化。结果　①GES 1细胞表达GRP受体mRNA ,Southern杂交进一步证明表达特异性mRNA。②GRP受体蛋白相对分子质量为 75× 10 3 ,该受体位于细胞膜。③蛙皮素可促进此细胞生长 ,而蛙皮素特异性受体拮抗剂可抑制此促生长作用。④蛙皮素对该细胞的促生长作用可被PKC抑制剂所抑制。⑤蛙皮素可引起细胞内IP3 含量显著增加以及引起细胞内PKC活性自细胞质向细胞膜转移。⑥蛙皮素作用GES 1细胞后可引起GRP受体mRNA表达增加。结论　此研究证明人胃黏膜上皮细胞系GES 1表达GRP受体mRNA和蛋白。蛙皮素对GES 1细胞的促生长作用是通过特异性受体介导 ,引起细胞内IP3增加和PKC活性转移来实现的。蛙皮素作用后引起该细胞GRP受体mRNA表达量增加 ,说明蛙皮素对其自身受体有上调作用     

Primary culture of human gallbladder epithelial cells

Growth requirements of epithelial cells isolated from the human gallbladder were examined. The growth of gallbladder epithelial cells (GBEC) was stimulated by medium conditioned with gallbladder fibroblasts (CM-GBF) in a dose-dependent manner. The conditioned medium derived from human embryo lung fibroblasts also showed similar growth stimulating activity for GBEC, suggesting that fibroblasts secrete a factor or factors which induce GBEC growthin vitro. CM-GBF in the presence of 10% fetal bovine serum increased GBEC growth up to 10 times the growth in the absence of CM-GBF supplement. GBEC cultured with CM-GBF showed hexagonal shape under a phase-contrast microscope, and also expressed cytokeratin and mucopolysaccharide in the cytoplasm, both of which are specific for GBEC. Electron microscopy revealed desmosomes and tight junctions between the cells and microvilli on the apical plasma membrane, suggesting that they regained morphological polarity in the medium containing CM-GBF. These results shows that CM-GBF is essential for the growth and the differentiation of GBEC in culture.     

Cell cycle arrest and apoptotic cell death in cultured human gastric carcinoma cells mediated by arsenic trioxide

AIM: To investigate the effect of arsenic trioxide on human gastric cancer cell line MKN45 with respect to both cytotoxicity and induction of apoptosis in vitro. METHODS: MKN45 cells were treated with arsenic trioxide (As2O3) at the concentration of 1, 5, and 10 μmol/L, respectively, for three successive days. Cell growth and proliferation were observed by cell counting and trypan blue exclusion. Cytotoxicity of As2O3 was determined by MTT assay. Morphologic changes were studied with light microscopy. Flow cytometry was used to assay cell DNA distribution and apoptotic cells were confirmed with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and DNA electrophoresis. RESULTS: The growth of MKN45 cells was significantly inhibited by As2O3 which was confirmed by colony-forming assay. After 7 d of culture with various concentrations of As2O3, colony-forming capacity of MKN45 cells decreased with As2O3 increment in comparison with that of control group. The inhibitory rate of colony-formation was 38.5%, 99.1%, and 99.5% when the concentration of As2O3 was 1, 5, and 10 μmol/L in culture medium, respectively. The cell number of a single colony in drug treatment groups was less than that of control group. The cell-killing rate of As2O3 to MKN45 cells was both dose- and time-dependent with an IC50 of (11.05±0.25) μmol/L After incubation in 10 μmol/L As2O3 for 24 h, the cell-killing rate was 27.1%, and it was close to 50% after 48 h. The results showed that As2O3 induced time- and dose-dependent apoptosis in MKN45 cells, blocked at G2/M phase. The apoptotic peak (sub-G1 phase) appeared and cell apoptotic rate in MKN45 cells was 18.3-32.5% after treatment by 10 umol/L As2O3 for 48 h. The percentage of G2/M cell of the experimental groups was 2.0-5.0 times than that of the control group. Gel electrophoresis of DNA from cells treated with each concentration of As2O3 for 48 h revealed a "ladder" pattern, indicating preferential DNA degradation at the internucleosomal, linker DNA sections. TUNEL also demonstrated strand breaks in DNA of MKN45 cells treated with As2O3, while control cells showed negative labeling. CONCLUSION: As2O3 can induce apoptosis of human gastric carcinoma cells MKN45, which is the basis of its effectiveness. It shows great potential in the treatment of gastric carcinoma.     

Lipoxygenase inhibitors induce arrest of tumor cells in S-phase of the cell cycle

Inhibitors of the lipoxygenase pathway of arachidonic acid metabolism represent a potential anti-tumor drugs. These compounds have been found to inhibit the growth and induce the apoptosis of various tumor cells both in vitro and in vivo. In this study, the effects of the lipoxygenase inhibitors esculetin and nordihydroguaiaretic acid (NDGA) on the progression of the cell cycle were investigated in eight mammalian cell lines of different origin. Flow cytometric analyses of cell cycle distribution after staining of DNA with propidium iodide or 7-aminoactinomycin D and DNA synthesis using incorporation of 5-bromo-2'-deoxy-uridine showed that both esculetin and NDGA suppress cell growth by interrupting the progression of cells through S-phase that results in their accumulation in this phase of the cell cycle. The possible mechanisms of these effects and the significance of the findings for the improvement of anticancer therapy targeted on cell cycle is discussed.     

Helicobacter pylori and mitogen-activated protein kinases regulate the cell cycle, proliferation and apoptosis in gastric epithelial cells

Background and Aims:  Helicobacter pylori infection activates mitogen-activated protein kinases (MAPK) and modulates cell proliferation and apoptosis. However, the relationship between H. pylori infection and MAPK signaling in controlling cell proliferation and apoptosis is not clear, nor has the role of MAPK on the gastric epithelial cell cycle and proliferation been established. Therefore, we investigated the effects of H. pylori infection and MAPK inhibition on these processes.
Methods:  Gastric epithelial cell lines (AGS and MKN45) were infected with H. pylori and/or treated with MAPK inhibitors. Cell cycle and apoptosis were measured by flow cytometry. Cell cycle proteins and proliferation were monitored by western blot and cell count, respectively.
Results:  Infection with H. pylori resulted in dose-dependent MAPK activation, cell cycle arrest, reduced proliferation and increased apoptosis. The effect of H. pylori and MAPK at various cell cycle checkpoints was noted: MEK1/2 and p38 inhibition increased H. pylori -induced cell cycle G₁ arrest, while JNK inhibition reduced G₁ arrest. MEK1/2 inhibition increased p21, p27 and cyclin E and JNK inhibition additionally increased cyclin D1 expression. Both inhibitors decreased cell proliferation. All inhibitors enhanced apoptosis after H. pylori infection. We also detected MAPK cross-talk in AGS cells: p38 and JNK inhibitors increased ERK activation. The p38 inhibitor increased JNK and the MEK1/2 inhibitor decreased JNK activation only during H. pylori infection.
Conclusions:  These results suggest H. pylori and MAPK differentially regulate the cell cycle, proliferation and apoptosis in gastric epithelial cells. The imbalance between H. pylori infection and MAPK activation likely contributes to the H. pylori -induced pathogenesis.