非吞噬细胞氧化酶1介导糖基化终末产物对牛视网膜周细胞凋亡的影响

目的:探讨非吞噬细胞氧化酶1(NOX1)激活是否介导糖基化终末产物(AGE)对牛视网膜毛细血管周细胞(BRP)的凋亡。方法:将原代培养BRP分为3组:对照组、AGE组(200mg/L AGE)、干预组(200mg/L AGE+NOX1RNAi)。用锥蓝排斥法观察各组BRP的增殖,使用流式细胞术检测BRP凋亡水平,采用免疫杂交法检测活性Caspase-3的表达。结果:AGE组BRP增殖率较对照组明显降低;干预组则较AGE组明显升高(P均<0.01)。活性Caspase-3在AGE组表达上调,而在干预组表达降低(P均<0.01)。结论:AGE对BRP增殖的抑制或者促凋亡作用可能是通过激活Caspase-3实现,而信号通路NOX1的激活可能介导了AGE对Caspase-3的活化。

周细胞凋亡与糖尿病性视网膜病变的研究进展

据调查，至2010年，我国18岁以上成年人罹患糖尿病（diabetes mellims，DM）的人数约有超过1．1亿，患病率高达11．6％，是糖尿病患病人数最多的国家嘲，西方国家的DM患病率也呈逐年上升趋势。糖尿病性视网膜病变（diabefic refinopathy，DR）是随着DM病程延长而逐渐出现的糖尿病性微血管病变，为DM的严重并发症之一。

糖基化终产物诱导牛视网膜毛细血管周细胞凋亡及凋亡调节基因的表达

目的 研究糖基化终产物 (advancedglycosylationendproducts,AGE)对培养的牛视网膜毛细血管周细胞凋亡及凋亡调节基因Bax、bcl 2表达的影响 ,以探讨糖尿病视网膜病变的发病机制。方法 在体外培养 3～ 6代近融合的视网膜毛细血管周细胞中加入不同浓度的AGE(8、32、12 5、5 0 0及2 0 0 0mg/L)液 ,于 4d后检测不同浓度AGE对牛视网膜毛细血管周细胞凋亡及凋亡调节基因Bax、bcl 2表达的影响。结果 周细胞与AGE作用 4d后 ,呈现出典型的细胞凋亡特征 ;AGE促周细胞凋亡(r=0 878,P <0 0 1)和凋亡调节基因Bax的表达 (r=0 85 5 ,P <0 0 1)及抑制凋亡调节基因bcl 2的表达 (r=- 0 85 0 ,P <0 0 1)呈剂量依赖性 ;而周细胞凋亡率与Bax/bcl 2的比率呈正相关 (r=0 80 8,P<0 0 1)。结论 AGE能以剂量依赖的方式促进周细胞的凋亡 ,周细胞的凋亡率取决于凋亡调节基因Bax/bcl 2的比率。细胞凋亡是糖尿病视网膜病变中毛细血管周细胞早期丧失的一种方式。

Induction of apoptosis and G2/M cell cycle arrest by oridonin in human gastric cancer BGC-823 cells

Aim To investigate in vitro apoptosis-induction effects of oridonin on gastric tumor cells BGC-823 and its effects on cell cycle, mitochondrial membrane potential and intracellular Ca^2＋ to shed light on the mode of its anticancer action. Methods The MTT method was used to investigate the inhibitory effect of oridonin on BGC-823 cells. The apoptosis-induction effect was evaluated by confocal laser microscopy and flow cytometry. The change of mitochondrial membrane potential and the increase of intracellular Ca^2＋ were assessed by fluorescence probe rhodamine123 and Fluo 3-AM, respectively, with flow cytometry. The expression of apoptosis and cell cycle related proteins was studied using western blotting. Results Oridonin inhibited BGC-823 cells growth with IC50 of 22.21 p, mol.L^-1. It induced apoptosis in a dose-dependent manner. In addition, it decreased mitochondria membrane potential, increased intracellular Ca^2＋, and activated pro-caspase 3. BGC-823 cells were arrested in G2/M cell cycle phase with lower expression of cyclin A protein. The up-regulation of p53 was observed before apoptosis and cell cycle arrest occurred. Conclusion Oridonin inhibits the proliferation of BGC-823 cells through G2/M cell cycle arrest and apoptosis induction, which is mediated by influx of Ca^2＋, up-regulation of p53, activation of caspase-3, and down-regulation of cyclin A.

EFFECT OF ACUPUNCTURE ON NEURONAL APOPTOSIS AFTER FOCAL CEREBRAL ISCHEMIC REPERFUSION INJURY IN RATS

Objective To observe the impacts of acupuncture on cell-cycl ODK4） and neuronal death in hippocampal neurons in rats with focal cerebra e-related factors （cyclin D1, schemic reperfusion injury Methods Middle cerebral artery occlusion （MCAO） was used to establish the model of cerebral ischemic reperfusion injury. Western blot （WB） and flow cytometry （FCM） were applied to the tests of cell-cycle-related factors and apoptosis respectively. Results In 48 h of reperfusion, the expressions of cell-cycle-related factors （cyclin D1, CDK4） in hippocampal neurons and apoptosis were increased. In acupuncture group, the expressions of cyclin DI and CDK4 and apoptosis were reduced remarkably （P 〈 0.01 ）. Conclusion Acupuncture plays the protective role in cerebral ischemic reperfusion injury, which is contributed probably to the modulation of cell-cycle-related factors to inhibit apoptosis.

Antileukemic activity of jaspolide B,an isomalabaricane-type triterpene from marine sponge Jaspis sp. on human promyeloleukemic HL-60 cells

The antiproliferative activity and underlying mechanisms of jaspolide B, an isomalabaricane-type triterpene, isolated from the sponge Jaspis sp., were investigated using human promyeloleukemic HL-60 cells. Jaspolide B arrested HL-60 cells in the G2/M phase of the cell cycle and induced apoptosis of HL-60 cells in a dose- and time-dependent manner. Moreover, the poly （ADP-ribose） polymerase （PARP） protein was cleaved by jaspolide in a dose- and time-dependent way. Jaspolide B with an ICs0 value of 0.61 μmol/L was found to be comparable efficacy as that of paclitaxel （IC50：0.78 μmol/L）. These results implicate the potential ofjaspolide B as a promising anticancer agent in chemotherapy of leukemia by arresting cell cycle progression at G2/M phase and triggering apoptosis.

Photoperiod Control of Apical Bud and Leaf Senescence in Pumpkin ( Cucurbita pepo ) Strain 185

Short_day (SD) induced the plant senescence in pumpkin ( Cucurbita pepo Linn.) strain 185. Structural assay, gene expression and a series of biochemical analyses were performed to analyze the senescence mechanism in pumpkin strain 185 exposed to SD. Two aspects of important changes initiated in SD exposure contributed to the senescence process. SD functionally led to the initiation of the apical transformation from vegetative to reproductive growth, and then programmed cell death (PCD) in the apical meristem, causing the loss of vigorous growth activity. Moreover, SD treatment resulted in the formation of a great number of dying cells in mesophyll tissue later in the development compared with the phenotype of plants under long_day (LD) conditions. During the senescence process, high expression of nuclease is an important molecular event. These results indicate that the initiation of senescence process in pumpkin stain 185 plants is closely related to the death of cells in apical meristem and mesophyll.

Effect of Activation-induced Cell Death of Peripheral Blood Mononuclear cells in Patients with Condyloma Acuminatum

Objective: To investigate the effect of activation-induced cell death (AICD) on cellular immune function in the condyloma acuminatum(CA). Methods: Peripheral blood mononuclear cells (PBMC) were isolated from normal healthy individuals (control group) and patients with CA. PBMC were cultured with PHA-P for 48h in vitro. Apoptosis of the PBMC was detected by flow cytometry. Supernatant cytokines (IL-2 and IL-10) were assayed by ELISA. Results: The rate of PBMC apoptosis in both CA group and control group in fresh PBMC was very low and similar in both groups(P>0.05). The rate of PBMC apoptosis within the CA group was noticeably increased compared to that of the control (P<0.001)af-ter PBMC were cultured for 48h. The level of IL-2 was significantly lower in the CA group than in the control group (P<0.001), The level of IL-10 was significantly higher in the CA group compared to thecontrol group(P<0.001). Conclusion: Study results indicate that AICD may affect cellular mediated immune function and play an important role in the pathogenesis of CA.

Berberine induces cell cycle arrest and apoptosis in human gastric carcinoma SNU-5 cell line

AIM： To investigate the relationship between the inhibited growth （cytotoxic activity） of berberine and apoptotic pathway with its molecular mechanism of action. METHODS： The in vitro cytotoxic techniques were complemented by cell cycle analysis and determination of sub-G1 for apoptosis in human gastric carcinoma SNU-5 cells. Percentage of viable cells, cell cycle, and sub431 group （apoptosis） were examined and determined by the flow cytometric methods. The associated proteins for cell cycle arrest and apoptosis were examined by Western blotting. RESULTS： For SNU-5 cell line, the IC （50） was found to be 48 μmol/L of berberine. In SNU-5 cells treated with 25-200 μmol/L berberine, G2/M cell cycle arrest was observed which was associated with a marked increment of the expression of p53, Wee1 and CDk1 proteins and decreased cyclin B. A concentration-dependent decrease of cells in G0/G1 phase and an increase in G2/M phase were detected. In addition, apoptosis detected as sub-Go cell population in cell cycle measurement was proved in 25-200 μmol/L berberine-treated cells by monitoring the apoptotic pathway. Apoptosis was identified by sub-Go cell population, and upregulation of Bax, downregulation of Bcl-2, release of Ca^2＋, decreased the mitochondrial membrane potential and then led to the release of mitochondrial cytochrome C into the cytoplasm and caused the activation of caspase-3, and finally led to the occurrence of apoptosis. CONCLUSION： Berberine induces p53 expression and leads to the decrease of the mitochondrial membrane potential, Cytochrome C release and activation of caspase-3 for the induction of apoptosis.

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.

Genistein inhibits invasive potential of human hepatocellular carcinoma by altering cell cycle, apoptosis, and angiogenesis

AIM： To study the in vitro and in vivo inhibitory effects of genistein on invasive potential of Bel 7402 hepatocellular carcinoma （HCC） cells and to explore the underlying mechanism. METHODS： Bel 7402 HCC cells were exposed to genistein. The invasive activity of tumor cells was assayed in transwell cell culture chamber, p125^FAK expression and cell cycle were evaluated by a functional assay. Cell apoptosis analysis was performed with TUNEL method. In addition, bilateral subrenal capsule xenograft transplantation of HCC was performed in 10 nude mice. Genistein was injected and the invasion of HCC into the renal parenchyma was observed. Nicrovessels with immunohistochemical staining were detected. RESULTS： Genistein significantly inhibited the growth of Bel 7402 cells, the inhibitory rate of tumor cells was 26 -42%. The invasive potential of Bel 7402 cells in vitro was significantly inhibited, the inhibitory rate was 11- 28%. Genistein caused G2/M cell cycle arrest, S phase decreased significantly. The occurrence of apoptosis in genistein group increased significantly. The expression of p125^FAK in 5 μg/mL genistein group （15.26±0.16%） and 10 μg/mL genistein group （12.89±0.36%） was significantly lower than that in the control group （19.75± 1.12%, P〈0.05）. Tumor growth in genistein-treated nude mice was significantly retarded in comparison to control mice, the inhibitory rate of tumor growth was about 20%. Genistein also significantly inhibited the invasion of Bel 7402 cells into the renal parenchyma of nude mice with xenograft transplant. The positive unit value of microvessels in genistein-treated group （10.422 ±0.807） was significantly lower than that in control group （22.330 ± 5.696, P〈 0.01）. CONCLUSION： Genistein can effectively inhibit the invasive potential of Bel 7402 HCC cells by altering cell cycle, apoptosis and angiogenesis, inhibition of focal adhesion kinase may play a significant role in this process.

The cell cycle related apoptotic susceptibility to arsenic trioxide is associated with the level of reactive oxygen species

Double staining flow cytometry was performed using 7-amino actinomycin D and 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate,to detect the level fluctuation of reactive oxygen species (ROS) during the cell cycle of normal NB4 cells. Our results showed that NB4 cells possessed higher level of ROS in G2/M phase than in G1 and S phases. Double staining flow cytometry,with TdT mediated dUTP nick end labeling (Tunel) and propidium iodide (PI),indicated that As2O3 (2 μM) could induce apoptosis in NB4 cells prevailingly from G2/M phase,and this efficacy was enhanced upon co-administration of 2,3-dimethoxy-1,4-naphthoquinone (DMNQ) (2.5 μM) which could produce the endogenous ROS. These results suggested that different ROS level in different cell cycle phases of NB4 cells might determin the selective induction of G2/M apoptosis and the cells' susceptibility to apoptosis by As2O3.

Effect of p27^(KIP1) on cell cycle and apoptosis in gastric cancer cells

AIM： To elucidate the effect of p27^KIP1 on cell cycle and apoptosis regulation in gastric carcinoma cells. METHODS： The whole length of p27^KIP1 cDNA was transfected into human gastric cancer cell line SCG7901 by lipofectamine. Expression of p27^KIP1 protein or mRNA was analyzed by Western blot and RNA dot blotting, respectively. Effect of p27^KIP1 on cell growth was observed by MTT assay and anchorage-independent growth in soft agar. Tumorigenicity in nude mice was used to assess the in vivo biological effect of p27^KIP1. Flow cytometry, TUNEL, and electron microscopy were used to assess the effect of p27^KIP1 on cell cycle and apoptosis. RESULTS： Expression of p27^KIP1 protein or mRNA increased evidently in SCG7901 cells transfected with p27^KIP1. The cell growth was reduced by 31% at 48 h after induction with zinc determined by cell viability assay. The alteration of cell malignant phenotype was evidently indicated by the loss of anchorage-independent growth ability in soft agar. The tumorigenicity in nude mice was reduced evidently （0.55±0.14 cm vs 1.36±0.13cm, P〈0.01）. p27^KIP1 overexpression caused cell arrest with 36% increase （from 33.7% to 69.3%, P〈0.01） in G1 population. Prolonged p27^KIP1 expression induced apoptotic cell death reflected by pre-G1 peak in the histogram of FACS, which was also confirmed by TUNEL assay and electron microscopy. CONCLUSION： p27^KIP1 can prolong cell cycle in G1 phase and lead to apoptosis, p27^KIP1 may be a good candidate for cancer gene therapy.

Paris chinensis dioscin induces G2/M cell cycle arrest and apoptosis in human gastric cancer SGC-7901 cells

AIM:To investigate the anti-tumor effects of Paris chinensis dioscin(PCD)and mechanisms regarding cell cycle regulation and apoptosis in human gastric cancer SGC-7901 cells.METHODS:Cell viability was analyzed by the 3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay.Cell apoptosis was evaluated by flow cytometry and laser scanning confocal microscope(LSCM)using Annexin-V/propidium iodide(PI)staining,and the cell cycle was evaluated using PI staining with flow cytom-etry.Intracellular calcium ions were detected under fluorescence microscope.The expression of cell cycle and apoptosis-related proteins cyclin B1,CDK1,cytochrome C and caspase-3 was measured by immunohistochemical staining.RESULTS:PCD had an anti-proliferation effect on human gastric cancer SGC-7901 cells in a dose-and time-de-pendent manner.After treatment of SGC-7901 cells with PCD,apoptosis appeared in SGC-7901 cells.Morpho-logical changes typical of apoptosis were also observed with LSCM by Annexin V/PI staining,and the cell number of the G0/G1 phase was decreased,while the number of cells in the G2/M phase was increased.Cell cycle-related proteins,such as cyclin B1 and CDK1,were all down-regulated,but caspase-3 and cytochrome C were up-regulated.Moreover,intracellular calcium accumulation occurred in PCD-treated cells.CONCLUSION:G2/M phase arrest and apoptosis induced by PCD are associated with the inhibition of CDK-activating kinase activity and the activation of Ca2+-related mitochondrion pathway in SGC-7901 cells.

The IAP family: endogenous caspase inhibitors with multiple biological activities

IAPs (inhibitors of apoptosis) are a family of proteins containing one or more characteristic BIR domains. These proteins have multiple biological activities that include binding and inhibiting caspases, regulating cell cycle progression, and modulating receptor-mediated signal transduction. Our recent studies found the IAP family members XIAP and c-IAP1 are ubiquitinated and degraded in proteasomes in response to apoptotic stimuli in T cells, and their degradation appears to be important for T cells to commit to death. In addition to three BIR domains, each of these IAPs also contains a RING finger domain.We found this region confers ubiquitin protease ligase (E3) activity to IAPs, and is responsible for the auto-ubiquitination and degradation of IAPs after an apoptotic stimulus. Given the factthat IAPs can bind a variety of proteins, such as caspases and TRAFs, it will be of interest to characterize potential substrates of the E3 activity of IAPs and the effects of ubiquitination byIAPs on signal transduction, cell cycle, and apoptosis.

Effect of ligand troglitazone on peroxisome proliferator-activated receptor γ expression and cellular growth in human colon cancer cells

AIM： To investigate the effect of troglitazone on peroxisome proliferator-activated receptor γ （PPARγ） expression and cellular growth in human colon cancer HCT-116 and HCT-15 cells and to explore the related molecular mechanism.METHODS： Human colon cancer HCT-116 and HCT-15 cells cultured in vitro were treated with troglitazone. Reverse transcription-polymerase chain reaction （RT-PCR） and Western blot were employed to detect the effect of troglitazone on PPARy expression. The proliferative activity was determined by MTT assay, cell cycle and apoptosis were detected by flow cytometry. Apoptosisrelated genes, cell cycle regulatory genes and p53 were examined by RT-PCR and Western blot respectively. RESULTS： The expression of PPARy in colon cancer HCT-116 and HCT-15 cells was up-regulated by troglitazone. Troglitazone inhibited proliferation, induced apoptosis and cell cycle G1 arrest in colon cancer cells. Troglitazone induced p53 expression in HCT-116 cells, but not in HCT-15 cells. The down-regulation of survivin and bcl-2 was found in both cell lines and up-regulation of bax was found only in HCT-116 cells, being consistent with growth inhibition in HCT-116 cells but not in HCT-15 cells. Troglitazone increased expression of p21^WAF1/CIP1 （p21）, p27^KIP1 （p27） and reduced cyclin D1 in HCT-116 cells while only a minor decrease of cyclin D1 was found in HCT-15 cells. CONCLUSION： Troglitazone is an inductor of PPARγ in colon cancer cells and inhibits PPARγ-dependently proliferation, which may attribute to cell cycle G1 arrest and apoptosis in colon cancer cells. Troglitazone may induce p53-independent apoptosis and p53- dependent expression of p21 and p27. Depending on cell background, different activation pathways may exist in colon cancer cells.

Growth inhibitory effect of wild-type Kras2 gene on a colonic adenocarcinoma cell line

AIM： To observe the growth inhibitory effect of wild-type Kras2 gene on a colonic adenocarcinoma cell line Caco-2. METHODS： Recombinant plasmid pCI-neo-Kras2 with wild type Kras2 open reading frame was constructed. The Caco-2 cells were transfected with either pCI-neo or pCI-neo-Kras2 using Upofectamine 2000. The expression of wild type Kras2 was examined by Northern blot analysis. And the expression of wild type Kras2 protein was examined by Western blot analysis. The effects of wild-type Kras2 on cell proliferation were analyzed by monotetrazolium （MTT） assay, meanwhile analyses of cell cycle and spontaneous apoptosis rate were carried out by flow cytometry （FCM）. RESULTS： The plasmid of pCI-neo-Kras2 was successfully established. The growth rate of cells transfected with pCI-neo-Kras2 was significantly lower than the control cells transfected with the empty pCI- neo vector （P 〈 0.05）. Cell cycle analysis revealed arrest of the pCI-neo-Kras2 transfected cells in G0/G1 phases, decreased DNA synthesis and decreased fractions of cells in S phase. The proliferative index of cells transfected with pCI-neo-Kras2 was decreased compared with the control cells （49.78% vs 64.21%）, while the apoptotic rate of Caco-2 cells with stable Kras2 expression increased （0.30% vs 0.02%）. CONCLUSION： The wild-type Kras2 gene effectively inhibits the growth of the colonic adenocarcinoma cell line Caco-2.

Effect of mutant p27^(kip1) gene on human cholangiocarcinoma cell line, QBC_(939)

AIM：To investigate the effects of exogenously mutated p27^kip1 （p27） on proliferation and apoptosis of human cholangiocarcinoma cell line, QBC939 in vivo.METHODS： Adenviral vectors were used to transfect mutated p27 cDNA into human QBC939 cell line. Expression of p27 was detected by RT-PCR. Western blot. Cell growth, morphological change, cell cycle, apoptosis and cloning formation were determined by MTT assay and flow cytometry.RESULTS： The expression of p27 protein and mRNA was increased signifi cantly in QBC939 cell line transfected with Ad-p27mt. The transfer of Ad-p27mt could signifi cantly inhibit the growth of QBC939 cells, decrease the cloning formation rate and induce apoptosis. p27 over expression caused cell cycle arrest at G0/G1 phase 72 h after infection with Ad-p27mt.CONCLUSION： p27 may cause cell cycle arrest at G0/G1 phase and subsequently lead to apoptosis. Recombinant adenovirus expressing mutant p27 may be potentially useful in gene therapy for cholangiocarcinoma.