Involvement of mitochondrial pathway in Taxol-induced apoptosis of human T24 bladder cancer cells

We examined a human urothelial cancer T24 cell line, which was exposed to clinically achievable concentrations of Taxol and detected the lethal effect of Taxol as measured by a cytotoxic dose-response curve. Marked nuclear condensation and the fragmentation of chromatin were observed by DAPI stain, DNA ladder formation, and flow cytometry at an LC(90)concentration of 0.8 microg/ml Taxol, which also induced a G2/M arrest. In response to Taxol-treatment, caspase-9 activity increased at 8 h, and both caspase-2 and -3 activities were increased twofold relative to control cultures at 16 h. Moreover, treatment with the broad-spectrum caspase inhibitor (z-VAD-fmk) or the caspase-9 specific inhibitor (z-LEHD-fmk) effectively protected T24 cells against Taxol-triggered apoptosis. Furthermore, the phosphorylation of Bcl-2 and Bcl-X(L) proteins in Taxol treated cells was detected at 8 h. In contrast, Taxol had no effect on the levels of Fas and FasL proteins and neither antagonistic, anti-Fas antibody affected Taxol-induced apoptosis. These results suggest that, following the phosphorylation of Bcl-2 and Bcl-X(L)proteins, Taxol-induced apoptosis is induced through the mitochondria-dependent pathway in T24 cells.     

人结肠癌耐药细胞系SW480/ADM的建立及其生物学特性

目的　建立人结肠癌SW4 8 0耐阿霉素细胞系 (SW4 8 0 /ADM) ,研究其耐药机制及逆转。方法　应用人结肠癌细胞系SW4 8 0,以递增阿霉素 (ADM)浓度的方法,体外连续培养建成一株SW4 8 0 /ADM。观察该细胞生长规律。用MTT比色法检测该耐药细胞系的多药耐药性;以流式细胞术检测该耐药细胞的细胞周期分布、细胞表面多药耐药基因 (MDR)的表达产物P-糖蛋白 (P gp) 、多药耐药相关蛋白 (MRP)及谷胱甘肽硫转移系统 (GSH/GST)的表达;用高效液相色谱仪检测耐药细胞内阿霉素含量。结果　SW4 8 0 /ADM细胞与SW4 8 0细胞相比,生长缓慢,倍增时间延长,细胞周期分布发生改变;SW4 8 0 /ADM细胞较SW4 8 0的阿霉素半数抑制浓度 (IC50 )增大 1 3. 2 2倍,并对多种抗癌药物产生耐药性。SW4 8 0 /ADM细胞表面MDR的表达产物P gp,MRP和GSH/GST的表达均较SW4 8 0细胞显著升高 (P< 0. 0 1 )。SW4 8 0 /ADM细胞内阿霉素含量明显低于SW4 8 0细胞。结论　SW4 8 0 /ADM细胞对阿霉素的耐药是获得性的,并呈多药耐药性特征,可用于对人结肠癌耐药、逆转和MDR机制等方面的研究。     

胰腺癌多药耐药细胞株BxPC-3/ADM的建立及耐药机制的初步探讨

目的 构建胰腺癌多药耐药细胞株BxPC-3/ADM,通过动态监测诱导耐药过程,探讨其耐药的可能机制.方法 逐步增加阿霉素浓度对BxPC-3细胞进行诱导,在不同的阿霉素诱导浓度,MTT法检测细胞对多种化疗药物的耐药指数,RT-PCR和Western印迹法检测细胞MDR1和MRP mRNA和蛋白的表达.结果 成功构建多药耐药细胞株BxPC-3/ADM;在0.05 μg/ml至8 μg/ml阿霉素诱导浓度,细胞对5-Fu、MMC和Gem的耐药指数无明显增加;在16 μg/ml浓度3种化疗药物的耐药指数有较明显上升,同时伴有MDR1 mRNA表达的明显增加;至32 μg/ml 5-Fu和Gem的耐药指数未再有继续上升,而MMC的耐药指数则继续上升,同时MDR1 mRNA表达未再增加,而MRP mRNA表达则明显增加.Western印迹实验显示MDR1和MRP蛋白表达变化与mRNA表达变化趋势一致.结论 MDR1基因在诱导早期的耐药中起主导作用,在后期则和MRP基因协同发挥作用.     

Experimental study on inhibitory effects of histone deacetylase inhibitor MS-275 and TSA on bladder cancer cells

ObjectiveTo investigate the inhibitory effect of histone deacetylase (HDAC) inhibitors (MS-275 and TSA) on T24 human bladder cancer cells in vitro, and explore the possible mechanism.MethodsThe MTT assay was employed to evaluate the inhibitory effect of MS-275 and TSA on T24 cell growth. FCM was used to analyze the variation of T24 cell cycle distribution and the apoptotic ratio after T24 cells were treated with MS-275 and TSA. Histone acetylation level was detected by Western blot. mRNA expression of p21 WAF1/CIP1, cyclin A, and cyclin E was measured by FQ-PCR. Dynamic changes of Bcl-2 and bax expression were detected by FCM.ResultsMS-275 and TSA inhibited T24 cell growth in a concentration and time-dependent manner. Treatment with 4 μmol/l MS-275 or 0.4 μmol/l TSA blocked cell cycling in the G0/G1 phase and induced a significant increase in cell apoptosis. MS-275 and TSA significantly increased the level of histone acetylation, induced p21CIP1WAF1 mRNA expression, and inhibited cyclin A mRNA expression, though no significant effect was observed on cyclin E. Bcl-2 expression was down-regulated, while bax expression was up-regulated.ConclusionHDAC inhibitors can block bladder cancer cell cycle in vitro and induce apoptosis. The molecular mechanism may be associated with increased level of histone acetylation, down-regulation of p21WAF1/CIP1 expression, up-regulation of cyclin A expression, and dynamic change of bcl-2 and bax expression.     

多药耐药相关蛋白在肝癌多药耐药细胞系HePG2/ADM中的作用

目的研究4种耐药蛋白：多药耐药蛋白（multi—drug resistance protein 1，MDR1），多药耐药相关蛋白1（multi—drug resistance related protein 1，MRP1），肺耐药蛋白（lung resistance protein，LRP），乳腺癌耐药蛋白（breast cancer resistance protein，BCRP）在肝癌多药耐药中的作用。方法通过培养液中阿霉素（adriamycin，ADM）浓度递增诱导法筛选培养，建立HePG2／ADM肝癌多药耐药细胞株；采用real time荧光定量PCR检测四种耐药蛋白mRNA在正常肝细胞系L02、肝癌细胞系HePG2及HePG2／ADM中的表达差异；Western blot检测3种细胞系中4种耐药蛋白的表达。结果（1）建立HePG2／ADM细胞系。MTT法检测阿霉素对HePG2／ADM细胞IC50为亲本细胞的282倍（P〈0．05）。（2）HePG2／ADM中MDR1和BCRP mRNA表达分别是HePG2的400倍（F=87．49，P〈0．05）和9倍（F=1006，P〈0．05）。MRP1和LRP mRNA表达差异无统计学意义（FMRPI=3．43，FLRP=2．44，Pall〉0．05）。（3）L02和HePG2中4种耐药蛋白mRNA的表达均无差异（FMDRI=1006，FBCRP=87．49，FMRPI=3．43，FLRP，=2．44，Pall〉0．05）。（4）Western blot检测发现HePG2／ADM细胞中MDR1，BCRP，LRP蛋白表达显著高于HePG2和L02细胞（FMDHI=28．68，FBCRP=18．60，FLRP=6．28，Pall〈0．05），MRP1蛋白表达不增高（FMRPI=0．70，P〉0．05）。（5）4种耐药蛋白表达在HePG2和L02细胞差异均无统计学意义（FMDRI=28．68，FBCRP=18．60，FMRPI=0．70，FLRP=6．28，Pall〉0．05）。结论MDR1和BCRP在HePG2／ADM多药耐药中起重要作用，HePG2／ADM多药耐药与MRP1和LRP可能无关。     

他克莫司在体外对肝癌细胞HepG2和HepG2.2.15增殖的影响

目的：研究他克莫司（tacrolimus ,FK506）在体外对肝癌肿瘤株HepG2和乙肝相关肝癌株HepG2.2.15增殖的影响。方法：体外培养肝癌细胞HepG2和HepG2.2.15,采用MTT法、流式细胞技术,分别检测细胞增殖、细胞周期、CyclinA。结果：FK506可以显著抑制HepG2和HepG2.2.15细胞增殖,其抑制增殖作用随剂量增加而增强;FK506诱导细胞产生G0/G1期阻滞,这种抑制作用有浓度依赖性;FK506对周期蛋白CyclinA表达的影响呈浓度负相关性,FK506浓度越高,周期蛋白CyclinA表达越少。结论：FK506可以抑制肝癌细胞HepG2和乙肝相关肝癌细胞HepG2.2.15的增殖,这种作用可能与诱导细胞周期阻滞有关。     

ERK/MAPK通路参与肝癌产生多药耐药的胞内信号传导

目的探讨微环境诱导肝癌产生多药耐药的胞内信号传导途径。方法分别使HepG2细胞在缺氧、低糖环境下生长或稳定整合HBX基因,运用Western蛋白印迹法检测这些细胞内ERK／MAPK的活性。用ERK／MAPK特异性阻断剂U0126处理这些细胞后,用Western蛋白印迹法检测缺氧诱导因子-1α（HIF—1α）和多药耐药相关蛋白的表达变化,逆转录聚合酶链反应和免疫细胞化学技术分别检测HIF-1α在mRNA水平表达量和部位的改变。结果不同环境下生长的HepG2细胞中,磷酸肜非磷酸化ERK／MAPK比例均有不同程度的增高。用U0126处理12h后,这些细胞中HIF-1α和多药耐药相关蛋白的表达下降,且HIF-1α表达由胞核向胞质转位,其mRNA水平无显著变化。结论ERK／MAPK信号通路是微环境诱导肝癌产生多药耐药的重要胞内信号传导途径。     

Aloe-emodin induces apoptosis in T24 human bladder cancer cells through the p53 dependent apoptotic pathway

PURPOSE: We investigated the anticancer effect of AE (1,8-dihydroy-3-[hydroxymethyl]-anthraquione) in the T24 human bladder cancer cell line (Food Industry Research and Development Institute, Hsinchu, Taiwan) by studying apoptosis regulation. MATERIALS AND METHODS: AE, which is purified from aloe vera leaves, has been reported to have antitumor activity. Cell viability, cell cycle and apoptosis were determined by flow cytometric methods. Levels of cyclins, cyclin-dependent kinase 1 and other enzyme were examined by Western blotting methods. RESULTS: AE inhibited cell viability, and induced G2/M arrest and apoptosis in T24 cells. AE increased the levels of Wee1 and cdc25c, and may have led to inhibition of the levels of cyclin-dependent kinase 1 and cyclin B1, which cause G2/M arrest. AE induced p53 expression and was accompanied by the induction of p21 and caspase-3 activation, which was associated with apoptosis. In addition, AE was associated with a marked increase in Fas/APO1 receptor and Bax expression but it inhibited Bcl-2 expression. CONCLUSIONS: AE induced apoptosis in T24 cells is mediated through the activation of p53, p21, Fas/APO-1, Bax and caspase-3.     

端粒酶活性与膀胱肿瘤T24细胞的诱导分化研究

目的：探讨人膀胱肿瘤T24细胞诱导分化治疗与端粒酶活性改变的关系。方法：用全反式维甲酸（ATRA）诱导分化人膀胱肿瘤T24细胞，用聚合酶链反应-酶联免疫吸附试验（PCR-ELISA）法检测T24细胞诱导分化后端粒酶活性变化，用流式细胞术检测细胞周期动力学改变。结果：T24细胞经ATRA诱导分化后，细胞周期动力学发生改变：S期细胞所占比例逐渐降低，G0/G1期细胞所占比例逐渐增加；端粒酶活性被明显抑制，与对照组比较，ATRA处理后1、3、5、7d端粒酶活性抑制率分别为10.9％、34.7％、81.2％、92.5％；端粒酶活性的高低与细胞所处的分化状态有关。结论：人膀胱肿瘤T24细胞诱导分化后，其细胞周期动力学发生改变，端粒酶活性被抑制，这可能为膀胱肿瘤的诱导分化治疗提供理论依据。     

Proliferation inhibition of glioma cells by vitamin K2

The antitumor effects of vitamin K2 were studied using three glioma cell lines: C6 (rat glioma cell), RBR17T and T98G (human glioma cell). The antitumor effects were estimated by count assay. The results was that vitamin K2 induced growth inhibition in a dose-dependent manner. The RBR 17T cells exposed to vitamin K2 for 72 hours resulted in oligonucleosomal DNA fragmentation and formed a ladder on agarose gel electrophoresis. Furthermore, the RBR17T cells exposed to vitamin K2 for 24 hours were significantly accumulated in the G0G1 phase of the cell cycle. Those results suggested that vitamin K2 can inhibit the proliferation of cells through the induction of cell cycle arrest and apoptosis for tumor cells. The combined treatment of vitamin K2 with ACNU or 5-FU or INF-beta or 1,25-dihydroxyvitamin D3 enhanced growth inhibition significantly. In conclusion, vitamin K2 can be a useful drug for the treatment of glioma.     

RNA干扰逆转人胃癌细胞多药耐药的研究

目的：研究RNA干扰沉默多药耐药（multidrug resistance,MDR）基因对胃癌多药耐药细胞株BGC-823/5-Fu生长的影响。方法：构建靶向MDR1的shRNA干扰质粒转染人胃癌多药耐药细胞株BGC-823/5-FU,噻唑蓝（MTT）法检测耐药细胞对5-Fu的敏感性,实时荧光定量PCR（Real-time-PCR）检测MDR1 mRNA表达的变化,Western blot检测各组细胞P-gp表达的变化,流式细胞术检测细胞周期变化、凋亡情况。结果：与RNAi-control组和normal组相比,RNAi-MDR1组细胞干扰质粒细胞的IC50明显降低,为2.104±0.242（P〈0.05）,敏感性的相对逆转率为76.8%;MDR1 mRNA表达明显下调（P〈0.05）;P-gp的表达水平降低（P〈0.05）;凋亡率明显升高至（5.757±0.684）%。结论：应用RNA干扰有效抑制了MDR1的表达,使P-gp的表达降低,增强了BGC-823/5-Fu细胞对5-Fu的敏感性,为寻找逆转胃癌细胞多药耐药有效方法奠定了基础。     

Identification of multidrug resistance-associated protein 1 and glutathione as multidrug resistance mechanisms in human prostate cancer cells: chemosensitization with leukotriene D4 antagonists and buthionine sulfoximine

OBJECTIVE: To assess the involvement of the multidrug resistance-associated protein 1 (MRP1) and the glutathione pathway in the multidrug resistant (MDR) phenotype of prostate cancer in vitro. MATERIALS AND METHODS: Chemoselection of human prostate cancer cell lines PC3 and DU145 with etoposide resulted in the resistant cell lines PC3-R and DU-R. Resistance against etoposide, doxorubicin and vincristine, and its reversal with leukotriene D4 antagonists MK-571 and zafirlukast, and buthionine sulfoximine (BSO), was assessed using tetrazolium-dye viability assays. Western blot analysis of MRP1 expression and glutathione content were measured, and MRP1 function assessed in fluorescence assays. RESULTS: MRP1 was increased in the MDR models; the glutathione content was significantly higher in PC3-R but there was no increase in glutathione in DU-R. Adding non-toxic doses of MK-571, zafirlukast or BSO significantly increased the sensitivity of the MDR models to cytotoxic drugs. MRP1 function was inhibited with MK-571 in the MDR models. CONCLUSION: MRP1 and glutathione mediate MDR in newly developed prostate cancer models.     

利用重构pc-MDR1质粒快速诱导肝癌细胞耐药

目的：从裸鼠原位耐药肿瘤组织中进行MDR1 cDNA的全克隆和pc-MDR1重组质粒的构建，并转染HepG2细胞，快速诱导其耐药，并筛选其抗性克隆。方法：设计单酶切位点引物，利甩长距离逆转录PcR(Long RT-PCR)技术，由HepG2耐药细胞扩增MDR1 cDNA，约3．8kb大小。将其插入至真核表达载体pcDNA3．0质粒中构建pc-MDR1诱导质粒，使其能够在真核细胞中表达p-gp蛋白。转染HepG2细胞，并用G418筛选出转染的细胞。结果：成功地扩增出3．8kb左右的MDR1 cDNA片段，经酶切鉴定、RT-PCR扩增特异片段和序列测序结果显示质粒构建初步成功，用G418筛选细胞耐药抗性克隆的时间约为14d。结论：从耐药肿瘤组织中进行MDR1 cDNA的全克隆和pc—MDR1诱导质粒的构建成功快速诱导了肝癌细胞发生耐药，为进一步研究肿瘤细胞的耐药机制奠定了很好的基础。     

人肿瘤坏死因子α联合溴隐亭对人肝癌裸鼠耐药模型耐药性逆转的研究

目的探讨人肿瘤坏死因子α(TNFα)联合溴隐亭(BCT)对人肝癌裸鼠耐药模型耐药性的逆转作用。方法将人肝癌细胞系HepG2及其经阿霉素(ADM)诱导建立的耐药细胞系HepG2ADM和转染TNFα基因后的耐药细胞系HepG2ADMTNFα分别原位种植BALB/C裸鼠肝脏,建立裸鼠原位肝移植瘤模型。64只裸鼠分为4组:HepG2组(HepG2细胞系种植瘤裸鼠),ADM组(HepG2ADM细胞系种植瘤裸鼠),TNFα组(HepG2ADMTNFα细胞系种植瘤裸鼠)和BCT组(HepG2ADMTNFα细胞系种植瘤裸鼠同时口服BCT),成瘤后均给以每天腹腔内注射0.15g/kg的氟脲嘧啶+1.5mg/kg的丝裂霉素+10mg/kg的ADM,连续3d;BCT组化疗的同时另行BCT灌胃治疗(6.25mg·kg-1·d-1)。B超观察种植瘤的大小变化,病理观察组织学结构及裸鼠生长状况和对化疗药物的敏感性。采用免疫组织化学和逆转录聚合酶链反应(RTPCR)检测各组种植瘤的多药耐药相关基因(MDR1)和肺耐药相关蛋白(LRP)在mRNA水平、蛋白水平的变化,末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法(TUNEL法)检测化疗后肿瘤组织凋亡指数情况。结果细胞系原位种植裸鼠肝脏成功率100%,种植瘤组织学特点符合人肝癌特征;TNFα组和BCT组种植瘤生长速度慢,与HepG2和ADM两组比较差异有统计学意义(P<0.05)。化疗14d后,BCT组重量抑瘤率(67%)最明显,与HepG2、TNFα和ADM3组比较差异有统计学意义(P<0.05)。4组均有MDR1和LRPmRNA表达,组间差异具有统计学意义(P<0.05);免疫组化显示TNFα和BCT组肿瘤组织MDR1蛋白表达比ADM组低,差异具有统计学意义(P<0.01),与HepG2组比较差异无统计学意义(P>0.05);BCT、TNFα组凋亡指数比ADM组高(P<0.05),且TNFα和BCT两组之间差异亦有统计学意义(P<0.05),但与HepG2组之间比较差异均无统计学意义(P>0.05)。结论TNFα基因能下调MDR1和LRPmRNA及蛋白表达,联合BCT能加强对化疗药物的敏感性。     

多药耐药相关蛋白在阿霉素诱导人肝癌细胞SMMC—7721耐药性产生中的作用及

目的 动态观察阿霉素（ＡＤＭ）诱导肝癌细胞ＳＭＭＣ－７７２１耐药性的产生,了解多药耐药相关蛋白（ＴＲＰ）在其耐药机理中的作用。方法 分别用逐步提高培养基中ＡＤＭ的浓度诱导ＳＭＭＣ－７７２１细胞和用含不用ＡＤＭ浓度的培养基直接短期培养ＳＭＭＣ－７７２１细胞的方法,诱导细胞产生耐药性,绘制剂量反应曲线,确定细胞耐药倍数,ＲＴ－ＰＣＲ法测定细胞ＭＲＰｍＲＮＡ的表达水平,流式细胞仪检测细胞内柔红霉素（ＤＮＲ）的浓度。结果 随着培养基中ＡＤＭ浓度的逐步提高,ＭＲＰｍＲＮＡ的表达也逐渐增强,细胞内ＤＮＲ浓度明显下降,ＳＭＭＣ－７７２１细胞的耐性逐渐增加;用含不同ＡＤＭ浓度的培养基直接培养亲代细胞后,虽然ＭＲＰｍＲＮＡ表达明显升高,但细胞内ＤＮＲ浓度仍维持较高水平,并且绝大部分细胞短期内死亡。结论 ＡＤＭ可以逐步诱导肝癌细胞     

二甲基亚砜诱导人肺癌细胞凋亡的研究

目的：研究二甲基亚砜（DMSO）对人肺癌细胞凋亡的诱导作用。方法：用不同浓度的DMSO处理体外培养的人肺癌细胞A549,应用普通光镜,荧光显微镜,MTT分析方法和流式细胞技术（FCM）检测肺癌细胞凋亡的形态学变化,细胞存活率,凋亡百分率和细胞周期分布的变化。结果：DMSO诱导A549细胞核DNA凝缩和核片段化,最后形成凋亡小体,随着DMSO浓度的增加和处理时间的延长,细胞存活率明显下降,其IC50为3．2％,4％的DMSO处理细胞12h,凋亡率高达33．0％,同时G0／1期细胞明显增加,S期和G2／M期细胞明显下降。结论：DMSO可诱导人肺癌细胞凋亡,并使细胞受阻于G0／1期而进入凋亡程序。     

体外瞬时转染TIMP-1基因促进成纤维细胞增殖

目的：探讨体外瞬时转染组织型金属蛋白酶抑制剂1（TIMP-1）质粒对小鼠成纤维细胞细胞周期和增殖的影响。方法：构建表达小鼠TIMP-1的质粒，体外转染小鼠成纤维细胞NIH3T3,以转染空质粒的NIH3T3细胞作对照，采用RT—PCR和westem印迹分析检测TIMP—1在基因和蛋白质水平的表达；采用BrdU法和MTT法检测细胞增殖能力和活力；流式细胞仪检测细胞周期的变化。结果：转染TIMP-1质粒的NIH3T3细胞在24h即有明显的TIMP-1mRNA表达和蛋白质表达上调；与转染空质粒的NIH3T3细胞相比，转染TIMP-1质粒的NI心L细胞48h的BrdU摄取率显著升高（P〈0．01），72h的m摄取率显著升高（P〈0．05）。流式细胞仪检测结果显示与转染空质粒的细胞相比，72h时TIMP-1质粒转染组G0／G1期细胞显著减少（P〈0．01），s期细胞比例显著升高（P〈0．01）。结论：体外瞬时转染TIMP-1质粒可以有效地使TIMP-1的基因和蛋白质水平在NIH3T3细胞高表达，TIMP-1高表达显著提高细胞BrdU和MTT摄取率，减少G0／（31期细胞比例，提高s期细胞比例，提示TIMP—1高表达能够促进戍纤维细胞增殖，从而加速间质纤维化的进程。