共轭亚油酸对胃癌MGC-803细胞增殖的影响

目的 研究共轭亚油酸（CLA）对体外培养人胃癌MGC-803细胞生长的影响。方法 采用体外培养人胃癌MGC-803细胞，用MTT比色、流式细胞光度术以及Cyclin D1蛋白表达检测的方法，观察不同浓度CLA（50．0、100．0、200．0μmol／L）对MGC-803细胞生长的影响。结果 MTT比色结果显示，不同浓度CLA可抑制人胃癌MGC-803细胞的增殖，72h的抑制率分别为48．61％、62．02％、66．33％，呈现剂量-效应关系（P〈0．05）。流式细胞仪检测表明，不同浓度CLA（50．0、100．0、200．0μmol／L）作用MGC-803细胞48h，C1期细胞从0μmol／L浓度组的32．2％分别上升到43．1％、59．7％、63．9％，出现G1期阻滞。免疫组织化学结果显示，Cyclin D1蛋白表达随着CLA浓度的增加呈现逐渐下降的趋势。结论 CLA对体外培养的人胃癌MGC-803细胞增殖有良好的抑制作用。     

过表达lncRNA-p21通过介导Wnt/β-catenin信号通路抑制胃癌MGC-803细胞的生长与转移

目的:探讨lncRNA-p21在调控胃癌MGC-803细胞生长与转移作用中的作用及Wnt/β-catenin信号通路在其中的功能。方法:在人胃癌MGC-803细胞中转染慢病毒以过表达lncRNA-p21。观察细胞形态、细胞增殖以及体内外迁移和侵袭能力,检测Wnt/β-catenin信号通路是否参与lncRNA-p21介导的抑制胃癌细胞增殖和生长作用。最后使用LiCl对Wnt/β-catenin信号通路进行验证。结果:LncRNA-p21过表达的胃癌MGC-803细胞发生了形态学的改变,表现为由纺锤状或星状形态变为较圆的低侵袭状态。LncRNA-p21在体内外均抑制了胃癌MGC-803细胞增殖和生长,体外实验表现为lncRNA-p21过表达减弱了胃癌MGC-803细胞迁移和侵袭能力。LiCl实验验证了Wnt/β-catenin信号通路介导了lncRNA-p21对胃癌MGC-803细胞增殖、迁移与侵袭的抑制作用。结论:LncRNA-p21可在体内外显著抑制胃癌MGC-803细胞的生长与转移,且该抑制作用可能通过抑制Wnt/β-catenin信号通路介导。     

四种人胃癌细胞体外增殖和侵袭能力比较

目的比较四种不同组织来源、不同分化程度的胃癌细胞MGC-803、HGC-27、BGC-823、SGC-7901的体外增殖和侵袭能力。方法分别培养四种细胞,用直接计数法绘制细胞生长曲线,计算其群体倍增时间;以细胞克隆形成率比较其增殖能力;体外划痕法和Transwells法比较四种细胞迁移、侵袭能力。结果与MGC-803和HGC-27相比,BGC-823和SGC-7901的生长速度依次减慢,群体倍增时间依次增加(P<0.05);平板克隆形成率从MGC-803、HGC-27、BGC-823到SGC-7901分别是42.7±2.2、38.6±1.6、28.9±1.7、21.3±1.9,差异有统计学意义(P<0.05)。体外划痕法和Transwells小室侵袭实验均表明MGC-803和HGC-27细胞的迁移侵袭能力较BGC-823和SGC-7901高,差异有统计学意义(P<0.05)。结论四株胃癌细胞株,从MGC-803、HGC-27、BGC-823到SGC-7901其增殖和侵袭能力逐渐下降。     

导入RASSF1A基因抑制膀胱癌细胞增殖的研究

[目的]探讨RASSF1A基因的表达对人膀胱癌细胞株体外增殖的影响.[方法]通过脂质体介导的基因转染法将野生型RASSF1A基因的真核表达载体及空载体转染膀胱癌BIU87细胞株.以四甲基偶氮唑蓝(MTT)法检测细胞的增殖程度,原位凋亡细胞检测技术和流式细胞仪检测膀胱癌BIU87细胞凋亡和细胞周期,Western blot检测膀胱癌BIU87细胞Cyclin D1蛋白表达的改变.[结果]成功建立稳定表达野生型RASSF1A基因的膀胱癌细胞株.野生型RASSF1A基因的表达可明显抑制膀胱癌细胞在体外的生长,可以显著降低BIU87细胞的增殖比和增高BIU87细胞的凋亡指数,与对照相组比差异显著( P <0.05).BIU87细胞的细胞周期发生 G1/S期阻滞,Cyclin D1蛋白的表达水平下调.[结论]野生型RASSF1A的重表达通过下调Cyclin D1,抑制膀胱癌BIU87细胞体外增殖.     

低浓度5-氟尿嘧啶对胃癌细胞生物学特性的影响

目的探讨低浓度5-氟尿嘧啶(5-FU)对胃癌细胞转录因子OCT4、SOX2及细胞增殖能力的影响。方法用MTT法检测并确定5-FU对胃癌细胞系MGC803、SGC-7901的半数抑制浓度(IC50),实时荧光定量PCR及western blot检测经不同浓度的5-FU处理后胃癌细胞转录因子OCT4、SOX2表达水平,平板克隆形成实验分析胃癌细胞增殖能力的改变情况。结果5-FU对MGC803、SGC-7901细胞的IC50分别为(28.82±1.25)和(23.95±1.34);低浓度5-FU(0.5、1μmol/L)处理后,胃癌细胞MGC803、SGC-7901中转录因子OCT4、SOX2在mRNA及蛋白质水平中的表达均增强,差异具有统计学意义(P0.05);平板克隆形成实验结果表明,经低浓度5-FU(0.5、1μmol/L)作用后胃癌细胞的增殖能力变强,形成的克隆数增多,差异有统计学意义(P0.05);但5-FU浓度为2μmol/L时OCT4和SOX4的表达有不同程度的减弱,且克隆形成能力也有下降。结论低浓度5-FU能增强胃癌细胞转录因子表达、促进胃癌细胞增殖。     

碱性成纤维细胞生长因子对人涎腺腺样囊性癌ACC-2细胞株增殖及MEK/ERK、MKP-1通路的影响

目的:观察碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)对人涎腺腺样囊性癌ACC-2细胞株增殖及MEK1/2、ERK1/2及MKP-1表达的影响。方法:培养人涎腺腺样囊性癌细胞株(ACC-2),MTT比色法测定不同浓度bFGF对细胞增殖的影响;免疫沉淀法纯化蛋白并ERK试剂盒测定ERK活性;免疫印迹法测定p-MEK1/2、p-ERK1/2及MKP-1表达。结果:MTT实验显示bFGF明显增强ACC-2细胞增殖,免疫沉淀法显示bFGF上调ERK活性,免疫印迹法显示bFGF明显增强p-MEK1/2、p-ERK1/2表达及抑制MKP-1表达。结论:bFGF可促进人涎腺腺样囊性癌ACC-2细胞株增殖,其途径与上调ERK活性、激活MEK/ERK通路、抑制MKP-1表达有关。     

ERK通路在DADS诱导人胃癌细胞分化中的作用

目的：研究ERK通路在DADS作用于人胃癌MGC－803细胞导致其分化中的作用机理。方法：用MTT法，免疫组化法及Westem Blot等技术进行分析。结果：DADS对MGC803细胞具有明显的生长抑制效应；DADS处理后ras P21表达减弱；ERK1／2（p44/p42)MAP激酶活性在DADS诱导人胃癌细胞分化中随时间变化（2－120min)在15－30min明显受抑制，MEK抑制剂U0126能加强该抑制;随浓度从20－35ug/ml抑制作用逐渐加强（P＜0．05），结论：DADS可能通过抑制ERK通路诱导人胃癌细胞分化。     

腺苷对人胃癌MGC-803细胞增殖与凋亡的影响

目的观察腺苷(adenosine)对人胃癌MGC-803细胞的增殖、凋亡的影响。方法 CCK-8法检测不同浓度腺苷(0.01~10 mmol/L)对胃癌MGC-803细胞增殖的影响。流式细胞仪检测腺苷(0.25、0.5、1 mmol/L)对细胞凋亡的影响。Western blot检测腺苷处理后细胞内凋亡相关蛋白和内质网应激相关蛋白的表达量。结果腺苷能抑制胃癌MGC-803细胞的活力,并且呈现浓度和时间依赖性(P0.05)。腺苷(0.25、0.5、1 mmol/L)处理24 h后,细胞的总凋亡率显著升高(P0.01)。腺苷可以引起凋亡相关蛋白Caspase-3活化片段的蛋白表达量上调(P0.01)。腺苷能诱导内质网应激(ERS)相关蛋白Caspase-4活化片段、p-JNK、CHOP、GRP78的表达量上调(P0.05)。结论腺苷可以抑制胃癌MGC-803细胞的增殖,并且促进凋亡,而内质网应激可能参与了腺苷引起的凋亡。     

黄芪甲苷通过抑制AKT和NF-κB通路诱导胃癌MGC-803细胞凋亡

目的观察黄芪甲苷对胃癌MGC-803细胞凋亡的影响并探讨其诱导凋亡可能的机制。方法应用四唑盐比色法(MTT法)观察黄芪甲苷对胃癌MGC-803细胞增殖的影响,应用流式细胞术检测其对胃癌MGC-803细胞周期和凋亡的影响,应用蛋白质免疫印迹(Western blot)方法观察其对蛋白激酶B(AKT)和核因子κB(NF-κB)等相关信号通路蛋白及凋亡相关蛋白B淋巴细胞瘤-2(BCL-2)、BCL2-Associated X的蛋白质(BAX)、天冬氨酸蛋白水解酶3(Caspase-3)的影响。结果黄芪甲苷能够抑制胃癌MGC-803细胞的增殖并促进其凋亡,并呈时间和剂量依赖性。同时其能够抑制AKT及NF-κB通路,抑制抗凋亡蛋白BCL-2的表达,促进促凋亡蛋白BAX的表达,降低BCL-2/BAX的比例,增加Caspase-3的活化。结论黄芪甲苷能够促进胃癌MGC-803细胞凋亡,推测可能通过抑制AKT和NF-κB通路,降低BCL-2/BAX的比例,增加Caspase-3的活化的机制而实现。     

熊果酸对人卵巢癌 SKOV3细胞增殖与凋亡的影响

【目的】探讨熊果酸(Ursolic acid,UA)对人卵巢癌 SKOV3细胞增殖与凋亡的影响。【方法】常规培养人卵巢癌 SKOV3细胞,应用 UA 浓度为5、10、20、40和80μmol/L 分别干预12 h、24 h 和48 h,采用 MTT 法检测细胞增殖;采用流式细胞仪检测细胞凋亡和细胞周期变化,应用 Western blot 技术检测细胞周期相关蛋白 P21、CyclinD1的表达水平。【结果】与空白对照组(0μmol/L UA)比较,40和80μmol/L UA 分别作用 SKOV3细胞12 h、24 h 和48 h 后 OD 值均显著降低(P <0.05);10、20和40μmol/L UA 作用24 h 后 SKOV3细胞早期凋亡率、晚期凋亡率和 G0/G1期比率较对照组升高,20和40μmol/L UA 作用24 h 后 SKOV3细胞周期蛋白 Cyclin D1明显降低而 P21水平显著升高(P <0.05)。【结论】体外实验中,UA 可抑制人卵巢癌 SKOV3细胞增殖和促其凋亡,其机制可能与细胞周期蛋白 Cyclin D1表达降低和 P21表达升高有关。     

Expression patterns of cyclins D1, E and cyclin‐dependent kinase inhibitors p21waf1/cip1, p27kip1 in colorectal carcinoma: correlation with other cell cycle regulators (pRb,p53 and Ki‐67 and PCNA) and clinicopathological features

Aberrations in the cell cycle regulators are common features of many tumours and several have been shown to have prognostic significant in colorectal cancer. The expression patterns of cyclins D1 and E as well as cyclin‐dependent kinase (CDK) inhibitors p21waf1/cip1 and p27kip1 and their interrelationship with other cell cycle checkpoint proteins [p53, pRb, Ki‐67 and proliferative cell nuclear antigen (PCNA)] were investigated in colorectal cancer in order to ascertain coregulation and influence on tumour behaviour or survival. These molecular markers were localisated immunohistochemically using the monoclonal antibodies anticyclin D1 (DCS‐6), anticyclin E (13A3), anti‐p21 (4D10), anti‐p27 (1B4), anti‐p53 (DO7), anti‐Rb (AB‐5), MIB1 and PC10 in colorectal cancer tissue from 97 patients. Data were analysed statistically using the spss software program. Overexpression of cyclin D1, cyclin E and p21waf1/cip1 proteins (>5% positive neoplastic cells) was observed in 5.9%, 30% and 7.2% of the cases respectively. Increased levels of cyclin D1 (p = 0.0001) and p21waf1/cip1 protein (p = 0.03) in tumours with mucous differentiation were observed. Overexpression of cyclin D1 was correlated with tumour stage (p = 0.03), the lymph node involvement (p = 0.02), as well as p21waf1/cip1 protein expression (p < 0.0001). Cyclin E was positively correlated with p21waf1/cip1 (p = 0.014), as well as with the cell proliferation as measured by PCNA‐labelling index (p = 0.011) and Ki‐67 score (p = 0.007). A positive relationship of p21waf1/cip1 expression with the proliferative‐associated index Ki‐67 was noted (p = 0.005). Downregulation of p27kip1 was observed in 47.4% of the cases and was correlated with downregulation of pRb (p = 0.002) and PCNA score (p = 0.004). The prognostic significance of cyclins D1, E and CDK inhibitors p21waf1/cip1, p27kip1 in determining the risk of recurrence and overall survival with both univariate (long‐rang test) and multivariate (Cox regression) methods of analysis showed no statistically significance differences. In conclusion, these findings suggest that, the levels of the cell cycle regulators studied, do not seems to have a prognostic value, in terms of predicting the risk of early recurrence and overall survival. In addition, the interrelationships, probably means their contribution to the regulation of cell growth, through different pathways in colorectal carcinogenesis.     

Role of p21waf1/cip1 in effects of oxaliplatin in colorectal cancer cells

Clinical studies have shown that oxaliplatin, a novel platinum derivative, is a potent chemotherapeutic agent for colorectal cancer when combined with 5-fluorouracil and leucovorin. Although the toxic activity is based on covalent adducts between platinum and DNA, its actual biological behavior is mostly unknown. In an effort to explore the mechanism of tumor susceptibility to oxaliplatin, we examined the cytotoxic effects of oxaliplatin in colorectal cancer cell lines in reference to p53 gene status. Although p53 gene status did not clearly predict sensitivity to oxaliplatin, p53 wild-type cells including HCT116 were sensitive but HCT116 p53-/- were found to be resistant to oxaliplatin. Oxaliplatin caused strong p21waf1/cip1 induction and G0-G1 arrest in p53 wild-type cells, whereas cisplatin did not induce G0-G1 arrest. Assays using p53 wild but p21waf1/cip1 null HCT116 cells revealed that oxaliplatin did not show G0-G1 arrest and reduced growth-inhibitory effects, suggesting that p21waf1/cip1 may be a key element in oxaliplatin-treated p53 wild-type cells. Although HCT116 is DNA mismatch repair-deficient, a mismatch repair-proficient HCT116+ch3 cell line displayed similar responses with regard to p21waf1/cip1-mediated growth inhibition and G0-G1 arrest. In p53 mutant cells, on the other hand, oxaliplatin caused an abrupt transition from G1 to S phase and eventually resulted in G2-M arrest. This abrupt entry into S phase was associated with loss of the p21waf1/cip1 protein via proteasome-mediated degradation. These findings suggest that p21waf1/cip1 plays a role in oxaliplatin-mediated cell cycle and growth control in p53-dependent and -independent pathways.     

Inhibition of histone deacetylases by chlamydocin induces apoptosis and proteasome-mediated degradation of survivin

The naturally occurring cyclic tetrapeptide chlamydocin is a very potent inhibitor of cell proliferation. Here we show that chlamydocin is a highly potent histone deacetylase (HDAC) inhibitor, inhibiting HDAC activity in vitro with an IC(50) of 1.3 nM. Like other HDAC inhibitors, chlamydocin induces the accumulation of hyperacetylated histones H3 and H4 in A2780 ovarian cancer cells, increases the expression of p21(cip1/waf1), and causes an accumulation of cells in G(2)/M phase of the cell cycle. In addition, chlamydocin induces apoptosis by activating caspase-3, which in turn leads to the cleavage of p21(cip1/waf1) into a 15-kDa breakdown product and drives cells from growth arrest into apoptosis. Concomitant with the activation of caspase-3 and cleavage of p21(cip1/waf1), chlamydocin decreases the protein level of survivin, a member of the inhibitor of apoptosis protein family that is selectively expressed in tumors. Although our data indicate a potential link between degradation of survivin and activation of the apoptotic pathway induced by HDAC inhibitors, stable overexpression of survivin does not suppress the activation of caspase-3 or cleavage of p21(cip1/waf1) induced by chlamydocin treatment. The decrease of survivin protein level is mediated by degradation via proteasomes since it can be inhibited by specific proteasome inhibitors. Taken together, our results show that induction of apoptosis by chlamydocin involves caspase-dependent cleavage of p21(cip1/waf1), which is strikingly associated with proteasome-mediated degradation of survivin.     

Failure of lamivudine to reverse hepatitis B virus-associated changes in ERK, Akt and cell cycle regulatory proteins

BACKGROUND: Chronic infection with hepatitis B virus (HBV) is a major factor associated with the development of hepatocellular carcinoma, but the mechanism by which this occurs is unknown. Treatment of chronic hepatitis B with lamivudine results in virological suppression and histological improvement; however, the role of lamivudine in preventing the development of hepatocellular carcinoma is less well defined. We recently reported that replication of HBV in a cell-culture system was associated with the upregulation of pERK, pAkt, pc-Myc, nuclear cyclin B1, p21(cip1) and p53 together with G2 cell cycle arrest. METHODS: In order to determine whether lamivudine is able to reverse the HBV-induced changes on signal transduction and cell cycle, we infected Huh7 cells with a recombinant adeno-HBV virus in the presence of 0-50 microM of lamivudine. Signal transduction and cell cycle regulatory proteins were analysed by western immunoblot. RESULTS: Although lamivudine was able to inhibit HBV replication, it failed to reverse the changes on ERK and Akt phosphorylation. Correspondingly, levels of phospho-GSK3beta and p21(cp1/waf1) were increased, as were cyclin D1, cyclin B1, p53 and pc-Myc. CONCLUSIONS: Lamivudine was ineffective in reversing the HBV-induced changes in signal transduction pathways and cell cycle regulatory proteins, indicating that the HBV-infected cells remained primed for oncogenic transformation despite viral suppression.     

用血清药理学方法观察中药复方制剂诱导人胃癌细胞凋亡的研究

采用血清药理学方法，流式细胞仪、琼脂糖凝胶电泳和透射电镜分析技术对中药复方制剂诱导人胃癌细胞凋亡情况进行检测和观察。结果可见；中药复方1号诱发肿瘤细胞，DNA裂解成典型的梯状电泳图谱，胞核团结，核染色质看边并裂解为碎块；G0／G1期细胞减少，产生典型凋亡峰。提示复方1号对胃癌是一种有潜力的治疗药物。     

ERK和P38信号转导途径对慢性髓系白血病细胞周期的调控作用

本研究探讨ERK和P38信号转导途径对慢性髓系白血病（CML）细胞周期的调控作用。以RT-PCR、Western blot和FCM方法分别检测CML患者白血病细胞和K562细胞中ERK、p38、cyclin D2、cyclin E、p27的mRNA表达及蛋白表达（其中ERK和P38为磷酸化ERK和磷酸化P38）及细胞周期分布,并分析其相关关系。结果表明：CML患者白血病细胞和K562细胞中ERK、P38、cyclin D2、cyclin E的mRNA表达和蛋白表达增高,P27的表达降低,且cyclin D2蛋白表达与cyclin E、ERK和P38蛋白表达呈正相关（P〈0.01）,与P27蛋白表达呈负相关（P〈0.01）。G0/G1期细胞减少,S期细胞增多,与对照组相比有显著性差异。结论：CML中P38、ERK mRNA表达和活性增加,激活下游的cyclin D2、cyclin E和P27等细胞周期调控因子,致使G0/G1期缩短,细胞快速通过G1/S转换点进入S期,加速细胞周期进程和细胞增殖,导致CML的发生。     

盐酸埃克替尼诱导肺癌HCC827细胞周期阻滞及其机制研究

目的 研究国家一类新药盐酸埃克替尼（Icotinib）对人非小细胞肺癌细胞HCC827的增殖抑制及细胞周期的影响,并探讨其作用机制.方法 实验分为空白组、对照组和Icotinib处理组,采用四甲基偶氮唑盐法（MTT）检测Icotinib对人肺癌HCC827细胞增殖的影响;流式细胞仪检测细胞周期变化;Western blot检测相关蛋白表达,应用SPSS 13.0进行统计学分析.结果 Icotinib以时间-剂量依赖的方式抑制HCC827细胞增殖,48 h的IC50为0.60 μmol/L,72 h的IC50为0.06 μmol/L;Icotinib诱导HCC827细胞发生明显的G1期阻滞并具有剂量依赖性.进一步对周期相关蛋白检测发现,Icotinib处理组较对照组相比,显著上调p21蛋白表达,抑制cyclin D1及cyclin A表达,但对cyclin E作用不明显.检测还发现Icotinib处理组明显下调ERK的磷酸化水平.结论 Icotinib能够明显抑制HCC827细胞增殖,引起细胞G1期阻滞,其机制可能与上调p21及抑制cyclin D1、cyclin A蛋白表达水平相关.并且MAPK/ERK信号通路在其介导的生物学效应中起重要作用.     

薯蓣皂苷元诱导人胃低分化粘液腺癌MGC-803细胞凋亡依赖caspase-3途径

目的研究薯蓣皂苷元（Diosgenin,Dio）诱导人胃低分化粘液腺癌（MGC-803）细胞死亡的机理。方法四唑蓝（MTT）比色法检测Dio对肿瘤细胞生长抑制作用;流式细胞仪检测Dio对MGC-803细胞膜Annexin V表达的影响;APO-BRDU试剂盒检测Dio对MGC-803细胞DNA的影响;酶联免疫分析仪测定Dio对MGC-803细胞caspase-3活力和caspase-3抑制剂Ac-DEVD-CHO对Dio诱导细胞死亡的影响。结果一定浓度范围内Dio对MGC-803细胞增殖有剂量、时间依赖性抑制作用;经Dio处理后Annexin V-FITC＋/PI-的凋亡细胞逐渐增多;随Dio剂量增大,DNA断裂碎片增多,凋亡细胞也逐渐增多。Dio作用细胞24 h,明显增强细胞caspase-3的活性。caspase-3抑制剂Ac-DEVD-CHO能部分抑制MGC-803细胞的凋亡。结论 Dio通过caspase-3途径诱导人胃低分化粘液腺癌细胞凋亡。