反义寡脱氧核苷酸抑制多药耐药基因mdr1表达并逆转耐药肝癌细胞的体外试验研究

目的:探讨反义寡脱氧核苷酸(ASODN)抑制多药耐药基因(mdr1)对耐阿霉素(ADM)肝癌细胞HepG2/ADM化疗敏感性的影响。方法:以多药耐药基因mdr1人工合成寡脱氧核苷酸(ODN),其中ODN分为ASODN和正义寡脱氧核苷酸(SODN),并采用脂质体转染技术将ODN与HepG2/ADM共培养,试验分为反义寡脱氧核苷酸(mdr1-ASODN)处理组、正义寡脱氧核苷酸(mdr1-SODN)对照组和空白对照组,通过逆转录聚合酶链式反应和蛋白免疫印迹法观察HepG2/ADM细胞中mdr1mRNA及其蛋白表达情况;MTT法观察HepG2/ADM细胞转染mdr1-ASODN前、后对化疗药物(ADM、顺铂、5-氟尿嘧啶)的敏感性。结果:与mdr1-SODN对照组和空白对照组比较,mdr1-ASODN处理组HepG2/AMD细胞中mdr1mRNA及其蛋白表达均明显降低(P<0.05);与转染前比较,HepG2/ADM细胞的增殖抑制率明显增加(P<0.05)。结论:ASODN能有效抑制mdr1基因表达,并恢复肝癌HepG2/ADM细胞对化疗药物的敏感性。     

甲基莲心碱增强阿霉素对骨肉瘤的抑制作用及机制初探

目的　研究甲基莲心碱 (Nifeine ,Nef)与化疗药物合用时 ,对骨肉瘤的化疗增敏作用及其机制。方法　用MTT法测定药物的细胞生长抑制率 ,PI染色流式细胞术检测细胞周期和细胞凋亡。间接免疫荧光流式细胞术和S P免疫组化检测蛋白表达。结果　 5 ,10 μmol·L-1Nef能降低ADM对Saos 2的IC50 。 10 μmol·L-1Nef增加了ADM诱导的Saos 2凋亡 ,增强了细胞的Rb蛋白表达 ,使G1期细胞增多。结论　Nef能增加ADM对Saos 2的化疗敏感性 ,其机制可能与增强Saos 2的Rb蛋白表达和G1期阻断有关     

DMBT1过表达对鼻咽癌细胞生物学行为的影响

目的 观察DMBT1过表达对鼻咽癌细胞生物学行为的影响.方法 利用脂质体LipofectamineTM 2000转染鼻咽癌5-8F细胞,Real time-PCR、Western-blot验证转染效率.MTT、流式细胞术检测DMBT1过表达对5-8F细胞增殖、凋亡和细胞周期的影响.Western-blot检测DMBT1过表达对多药耐药基因(P-gp)、肿瘤抑制基因p53蛋白表达的影响.MTT法检测DMBT1过表达对化疗药物敏感性的影响.结果 转染pcDNA3.1/DMBT1的5-8F细胞中DMBT1表达显著上调(P<0.05),提示成功构建稳定表达DMBT1基因的鼻咽癌5-8F细胞.DMBT1过表达的鼻咽癌5-8F细胞增殖能力减慢、凋亡率、G0/G1期细胞比例及p53蛋白表达增高,S期、G2/M期细胞比例及P-gp蛋白表达降低,同时细胞对顺铂敏感性增加(P<0.05).结论 DMBT1过表达能够显著抑制鼻咽癌5-8F细胞增殖,诱导其凋亡,并提高癌细胞对化疗药物敏感性.     

RNA干扰靶向cyclin D1基因对K562细胞化疗增敏的研究

目的 cyclin D1基因在细胞周期调控中起关键性作用.研究表明其过表达与肿瘤的发生、发展及预后密切相关;并且与肿瘤细胞对化疗药物抗拒性有关.抑制Cyclin D1蛋白表达可达到化疗增敏作用.本研究利用RNA干扰(RNAi)技术体外观测其对K562细胞cyclin D1基因的沉默效应及增强阿霉素(ADM)对K562细胞毒性作用.方法 体外构建靶向cyclin D1基因的小发夹RNA(shRNA)表达质粒,通过壳聚糖介导转染K562细胞,Western blot分析检测转染前后Cyclin DI蛋白表达变化,流式细胞仪检测细胞周期分布及凋亡率的影响以及MTT法检测K562细胞对ADM敏感性的变化.结果 构建靶向cyclin D1基因的shRNA表达质粒(pshRNA-419和pshRNA-575)经壳聚糖转染后,能显著抑制cyclin D1基因表达;影响K562细胞周期分布,诱导细胞凋亡,并降低ADM半数抑制浓度,提高了化疗敏感性.而设计一碱基突变的序列所构建的质粒并无上述生物学效应.结论 沉默K562细胞cyclin D1基因表达可达到有效的化疗增敏目的.     

血管内皮生长因子反义核酸提高前列腺癌PC3细胞对化疗药物敏感性的研究

目的探讨血管内皮生长因子(VEGF)反义核酸对前列腺癌细胞PC3对常用化疗药物作用的影响,联合反义核酸和紫杉醇治疗裸鼠移植肿瘤。方法采用新型脂质体Oligofectamine携带VEGF反义核酸转染前列腺癌细胞PC3。定量反转录-聚合酶链反应(RT-PCR)和Western杂交的方法检测细胞VEGFmRNA和蛋白的表达,四甲基偶氮唑蓝法(MTT)检测转染反义核酸的细胞对化疗药物的敏感性,联合反义核酸和紫杉醇对裸鼠移植肿瘤进行治疗,观察肿瘤抑制率,计算药物相互作用指数(CDI)。结果新型脂质体携带VEGF反义核酸转染前列腺癌细胞PC3,与对照组和正义组比较,反义组细胞VEGFmRNA和蛋白的表达明显下降,对2种前列腺癌常用化疗药物紫杉醇和米托蒽醌的敏感性明显增强(P<0.05)。治疗裸鼠移植肿瘤28d后肿瘤生长抑制率分别为反义组58.5%,紫杉醇组60.2%,联合组84.1%,CDI=0.97。结论 VEGF反义寡核苷酸抑制VEGF的表达,提高细胞对化疗药物的敏感性,联合反义核酸和紫杉醇可以更有效地抑制肿瘤生长,并且2种药物具有协同作用。     

RNA干扰GRP78联合顺铂体外抗瘤效应研究

目的:观察GRP78靶向RNA干扰联合化疗药物对人小细胞肺癌细胞系H446的体外抗瘤效应。方法:构建干扰GRP78质粒psiSTRIKETM/GRP78并转染H446细胞系;采用CFSE染色和PI-AnnexinV染色,通过流式细胞术分析干扰GRP78联合化疗药物对H446细胞增殖和凋亡的影响。结果:与化疗药物单独作用相比,干扰GRP78的表达联合化疗药物共同作用能显著抑制肿瘤细胞增殖,并诱导其凋亡。结论:干扰GRP78的表达可有效增加小细胞肺癌细胞对化疗药物的敏感性。     

乳腺癌耐受蛋白介导的5-氟尿嘧啶耐受及机制

目的筛选乳腺癌耐受蛋白(BCRP)介导的耐受药物,探讨BCRP介导抗肿瘤药物耐受的机制,优化以BCRP表达检测结果为评价指标,为肿瘤临床化疗方案提供有价值的资料。方法不同浓度的抗肿瘤药物分别处理BCRP呈不同程度表达的PA317/Teton/TREBCRP细胞,经MTT法筛选出BCRP介导的耐受药物。高效液相色谱仪检测耐受药物在细胞内的相对剂量。采用核DNA染料Hochest33258荧光染色技术和流式细胞术检测耐受药物诱导的细胞凋亡。结果随着细胞BCRP表达的增高,PA317/Teton/TREBCRP细胞对5氟尿嘧啶(5Fu)、甲氨蝶呤、多柔比星、吡柔比星、依托泊苷、米托蒽醌等药物的耐药指数增高(P<0.05),而对如紫杉醇、顺铂、长春碱、丝裂霉素、长春地辛等药物均敏感。细胞的BCRP表达量与胞内5Fu浓度具有负相关性(r=-0.885,P<0.05)。随着细胞BCRP表达的增高,经5Fu处理后细胞凋亡率随之降低(P<0.05),而Ko143能显著提高BCRP表达细胞的凋亡率(P<0.05)。结论BCRP能增强细胞对5Fu所致的凋亡耐受。     

Caspase-4活化参与TRAIL诱导的胃癌细胞凋亡

目的研究caspase-4在肿瘤坏死因子相关凋亡诱导配体(tumor necrosis factor-related apoptosis-inducing ligand,TRAIL)诱导胃癌细胞凋亡中的作用。方法采用碘化丙啶染色,流式细胞术检测TRAIL和caspase-4抑制剂(z-LEVDfmk)单独或联合作用对胃癌细胞凋亡的影响;化学合成3条针对caspase-4基因的小干扰RNA(small interfering,siRNA),用脂质体法转染胃癌细胞,采用Western blot验证沉默效果,流式细胞术观察转染后对TRAIL诱导胃癌细胞凋亡的影响;Western blot检测TRAIL作用后葡萄糖调节蛋白78(78-ku glucose-regulated protein,GRP78)的表达情况,以内质网应激经典诱导剂衣霉素(tunicamycin,TM)为参照;Western blot检测TRAIL作用后caspase-3和caspase-4蛋白的表达情况。结果 z-LEVD-fmk能明显地抑制TRAIL诱导的胃癌细胞凋亡(P<0.05);与阴性对照相比,转染caspase-4 siRNA后caspase-4蛋白表达水平明显下降,且转染后细胞凋亡率降低(P<0.05);和TM相比,TRAIL能诱导较低程度的内质网应激反应;在TRAIL处理的早期caspase-4和caspase-3即活化。结论 Caspase-4的活化参与了TRAIL诱导的胃癌细胞凋亡,这可能与TRAIL诱导的内质网应激有关。     

细胞信号转导抑制因子1沉默增强人口腔癌细胞对化疗药物的敏感性

目的 研究细胞因子信号转导抑制因子1(SOCS1)基因沉默对人口腔癌细胞化疗药物敏感性的影响及相关机制。方法 Western blotting及实时定量PCR验证SOCS1干扰序列沉默人口腔癌KB细胞株中SOCS1的表达水平；MTT法分析细胞对化疗药物敏感性的变化；流式细胞术检测细胞凋亡。结果 将SOCS1干扰片段转染KB细胞后,SOCS1 mRNA及蛋白表达水平均明显降低。沉默SOCS1表达后,化疗药物5-氟尿嘧啶和长春新碱对KB细胞的半数抑制浓度(IC50)均显著变小(P<0.05),SOCS1沉默还可增加长春新碱诱导的细胞凋亡(P<0.05),SOCS1表达抑制后KB细胞NF-κB和Caspase-3的蛋白表达水平明显降低,与对照组比较差异均有统计学意义(P<0.05)；结论 SOCS1表达有效抑制后,人口腔癌细胞KB对化疗药物的敏感性增强,且促进化疗药物诱导的肿瘤细胞凋亡。     

mdr1反义寡核苷酸增强多药耐药肝癌细胞HepG2/ADM化疗敏感性的实验研究

目的：探讨在体外实验条件下mdr1反义寡核苷酸对多药耐药肝癌细胞株化疗敏感性的影响。方法以肝癌细胞HepG2/ADM为研究对象,设立mdr1反义寡核苷酸组和空白试剂组作对照,利用脂质体包载肿瘤耐药基因mdr1的反义寡核苷酸进行细胞转染,通过反转录聚合酶链反应（RT-PCR）、免疫印迹实验（Western blotting）分别检测mdr1基因mRNA和P-gp蛋白表达,通过MTT实验检测细胞转染前后对阿霉素（ADM）、顺铂（DDP）和5-氟尿嘧啶（5-FU）的化疗敏感性。结果 HepG2/AMD肝癌细胞经反义寡核苷酸处理后,mdr1 mRNA、P-gp蛋白表达水平均明显降低,对ADM、DDP 和5-FU的化疗敏感性明显增强。结论反义寡核苷酸能在体外有效增加肝癌细胞HepG2/ADM对化疗药物的敏感性。     

p-JNK在结肠癌组织中的表达及抑制JNK通路后HT-29细胞增殖和凋亡变化

目的研究p-JNK在结肠癌组织中的表达以及抑制JNK信号通路后人结肠癌HT-29细胞增殖和凋亡的变化。方法使用免疫组织化学方法检测50例结肠癌组织标本和50例正常结肠组织标本中p-JNK的表达情况并和临床资料进行比较分析;在人结肠癌细胞株HT-29中使用SP600125抑制JNK信号通路后,MTT法检测细胞增殖,TUNEL法检测凋亡。结果 p-JNK在结肠癌组织中的表达水平明显高于正常对照组织(P<0.05);并和淋巴结转移、肿瘤分化程度、肿瘤的侵犯深度相关(P<0.05);而与肿瘤部位无关。抑制JNK信号通路后,HT-29细胞中的p-JNK表达降低(P<0.05);增殖减少,凋亡增加(P<0.05)。结论在结肠癌组织中存在p-JNK的高表达,抑制JNK信号通路能降低人结肠癌细胞株HT-29细胞的增殖,并促进凋亡;JNK信号通路和结肠癌的发生发展有关。     

瘦素对5-氟尿嘧啶损伤结肠癌细胞的影响

目的探讨不同浓度的瘦素对5-氟尿嘧啶(5-FU)损伤结肠癌细胞的影响。方法同时用5-FU及不同浓度的瘦素进行体外干预结肠癌HT-29细胞株。MTT法检测5-FU50%细胞生长抑制率(IC50)的变化。流式细胞仪、原位末端转移酶标记法(TUNEL)进行周期及凋亡分析。以RT-PCR方法检测caspase-9,caspase-3mRNA的表达。结果瘦素抑制5-FU对HT-29的杀伤作用。抑制5-FU诱导的细胞周期阻滞及细胞凋亡。RT-PCR表明加入瘦素后caspase-9,caspase-3mRNA的表达均下降,且呈剂量依赖性。结论瘦素通过下调caspase-9,caspase-3的表达促进结肠癌细胞产生凋亡抵抗,抑制5-FU的损伤作用。     

A glycoprotein from Laminaria japonica induces apoptosis in HT-29 colon cancer cells

We isolated a novel glycoprotein from the brown alga Laminaria japonica that has antiproliferative effects on HT-29 colon cancer cells. We also identified the mechanism by which this glycoprotein, named LJGP, induces apoptosis. MTS assays showed that LJGP inhibited the proliferation of several cancer cell lines (AGS, HepG2, HT-29) in a dose-dependent manner. Especially in HT-29 cells, proliferation was significantly decreased. LJGP treatment on HT-29 displayed several apoptotic features, such as DNA fragmentation, sub-G1 arrest, caspase-3 activation, and PARP degradation. Consistent with sub-G1 arrest, LJGP decreased the expression of Cdk2, cyclin E, cyclin D1, PCNA, E2F-1, and phosphorylated pRb. Furthermore, the increase of p27 expression was observed. We also determined that LJGP-induced apoptosis leads to the formation of a death-induced signaling complex of Fas, FADD, and procaspase-8. LJGP induced the reduction of mitochondrial membrane potential with activation of the Bcl-2 family of proteins and caspase-9. These findings suggest that LJGP inhibits HT-29 cell proliferation by inducing apoptosis, which may be mediated via multiple pathways, including the Fas signaling pathway, the mitochondrial pathway, and cell cycle arrest. Therefore, LJGP can be a useful treatment option for colon cancer in humans.     

miR-346靶向调控SFRP4介导5-FU诱导的结肠癌细胞毒性

目的观察miR-346及SFRP4对5-FU诱导的结肠癌细胞毒性的影响,为结肠癌化疗增效提供新的靶基因。方法构建pcDNA3.1-SFRP4上调SFRP4表达,以pcDNA3.1-SFRP4、NC、Con-miR、miR-346、miR-346+Vector、miR-346+SFRP4等转染SW480和HT-29细胞,Western blot法观察miR-346上调或下调后对SFRP4蛋白水平的影响,MTT观察不同转染条件下5-FU细胞存活率变化,流式细胞术观察细胞凋亡变化。结果 SFRP4可增加5-FU诱导的SW480、HT-29细胞毒性及细胞凋亡,miR-346能够降低5-FU诱导的SW480、HT-29细胞毒性及细胞凋亡。miR-346对SFRP4表达具有负向调控作用。结论 miR-346通过负向调控SFRP4表达降低5-FU诱导的结肠癌细胞毒性。     

PEITC Induces G1 Cell Cycle Arrest on HT-29 Cells Through the Activation of p38 MAPK Signaling Pathway

Phenethyl isothiocyanate (PEITC), an isothiocyanate abundantly found in cruciferous vegetables have been shown to induce apoptosis through MAPK pathway in prostate and colon cancer cells. In the present study, we investigate the effect of PEITC on cell cycle regulation of HT-29 colon cancer cells. Using flow cytometry and Western blot analyses, we found that PEITC significantly induced G1 cell cycle arrest in HT-29 cells. We showed that the cell cycle arrest was not related to beta-catenin translocation into the nucleus. Interestingly, inhibition of p38 attenuated the cell cycle arrest, suggesting that cell cycle arrest by PEITC was caused by the activation of MAPK pathway. Treatments of PEITC resulted in a dose-dependent down-regulation of cyclins A, D, E and pRb protein expression. The down-regulation can be attributed to the activation of the p38 pathway, since inhibition of its activities by specific inhibitor blocked PEITC's ability to decrease the expression level of cyclins A and D and attenuate cell cycle arrest effect of PEITC. In conclusion, this study shows for the first time that PEITC can arrest HT-29 cells in G1 phase by down-regulation of cyclins through the activation of p38 MAPK signaling pathway.     

活性氧介导5, 7- 二甲氧基黄酮诱导结肠癌HT- 29 细胞凋亡

目的研究5,7-二甲氧基黄酮（5,7-dimethoxyflavone,DMF）诱导体外培养人结肠癌HT-29细胞凋亡作用及其机制。方法以HT-29细胞为研究对象,利用ELISA法测定细胞DNA断裂,流式细胞术检测细胞凋亡率和活性氧（ROS）水平。结果DMF激活HT-29细胞ROS生成（P〈0．05）,呈浓度依赖性。DMF以浓度依赖方式促进HT-29细胞DNA断裂（P〈0．05）,同时,诱导细胞凋亡率增高（P〈0．05）;10μmol．L^-1N-乙酰半胱氨酸预孵育30min,能有效阻断DMF诱导ROS生成和细胞凋亡作用（P〈0．05）。结论DFM通过促进结肠癌HT-29细胞ROS生成诱导细胞凋亡。     

5-氨基水杨酸抗HT-29细胞增殖作用及部分机制

目的观察5-氨基水杨酸（5-aminosalicylicacid,5-ASA）对人结肠癌HT-29细胞增殖抑制作用及可能机制。方法采用MTT法测定5-ASA抗HT-29细胞增殖的量效和时效关系,采用TUNEL法和免疫细胞化学法探讨作用机制。结果模型对照组HT-29细胞增殖明显,不同剂量5-ASA对体外培养的结肠癌HT-29细胞增殖均具有明显抑制作用,呈剂量和时间依赖性;5-ASA在10-500μmol·L^-1剂量下,均可使HT-29细胞凋亡率增加,增殖细胞核抗原（PCNA）表达减弱;5-脂氧化酶（5-lipoxygenase 5-LOX）和环氧化酶-2（cycloxygenase-2cox-2）蛋白表达均逐渐降低,且5-LOX减弱程度大于COX-2。结论5-ASA具有抗HT-29细胞增殖作用,机制可能与阻断COX-2和5-LOX通路有关。     

Induction of colon cancer cell death by 7-hydroxystaurosporine (UCN-01) is associated with increased p38 MAPK and decreased Bcl-xL

UCN-01, a selective inhibitor of protein kinase C, is known to inhibit the growth of cancer cells. Although it is currently undergoing clinical evaluation, information about its effect on human colon cancer is limited and the mechanism responsible is lacking. The objective of this study was to examine the cytotoxicity of UCN-01 to human colon cancer cells in vitro and its effect on the apoptotic molecules. HT-29, a radiation- and chemotherapy-resistant human colon cancer cell, was used in the study. Cell death/apoptosis was determined by the MTT assay and DNA fragmentation measurement. NF-kappaB activity was measured by an enzyme immunoassay method. Western blot was employed to examine the expression of relevant apoptotic molecules. The result showed that UCN-01 could induce apoptosis of human colon cancer cells in a time- and dose-dependent manner. It markedly reduced the expression of Bcl-xL, but enhanced the level of p38 MAPK. In addition to Bcl-xL and p38 MAPK, UCN-01 also increased both caspase-3 and peroxisome proliferator activated receptor gamma protein levels. HT-29 cells transfected with exogenous Bcl-xL showed a significant increase in NF-kappaB activity and prevented apoptosis induced by UCN-01. The overexpression of Bcl-xL also reversed other relevant molecular changes observed in UCN-01-treated cells. In conclusion, UCN-01 exerted an antitumor effect in human colon cancer cells by inducing apoptosis. The mechanism responsible appeared to be related to reduction of Bcl-xL and increased p38 MAPK. The overexpression of Bcl-xL can significantly prevent apoptosis induced by UCN-01.     

Interleukin-2 enhances susceptibility of colon cancer cells to FasR mediated apoptosis by up-regulating Fas receptor level and down-regulating FAP-1 expression

Colon cancer cells are resistant to FasR-mediated apoptosis, which contributes to their evasion from immune attack by CTLs and NK cells. FasR refractoriness of the malignancies was reported to result from loss of Fas receptors and overepression of Fas-associated phosphatase-1 (FAP-1). Therefore, we investigated the effects of recombinant IL-2 on FasR and FAP-1 expression of colon cancer cells, and its influence on the sensitivity of colon cancer cells to FasR-mediated apoptosis. Colon cancer cell lines SW480, HT-29 and CaCo2 were incubated with IL-2 for different periods of time. Sensitivity of the cells to FasR-mediated apoptosis was assessed by measuring their apoptosis after treated with agonistic anti-FasR MAb CH-11. Additionally, Fas receptor levels were examined by immunofluorescence and mRNA expression of FasR and FAP-1 was investigated by RT-PCR: IL-2 incubation increased CH11-induced apoptosis in all colon cancer cell lines in a time-dependent manner. In parallel, IL-2 up-regulated Fas receptor expression on HT29 and CaCo2 cells at both protein and mRNA levels, which were low before treatment, while it served to maintain high expression of FasR on SW480 cells. Additionally, IL-2 down-regulated FAP-1 mRNA expression on SW480 and CaCo2 cells, which was high before treatment. However, low expression of FAP1 on HT-29 cells remained stable after IL-2 treatment. Thus, IL-2 enhances susceptibility of colon cancer cells to FasR-mediated apoptosis by up-regulating Fas receptor levels and by down-regulating FAP-1 expression, which accounts for its therapeutic effects on abolishing immune evasion in colon cancer cells.     

Relationship between endogenous colony stimulating factors and apoptosis in human colon cancer cells: role of cyclo-oxygenase inhibitors.

1. Nonsteroidal anti-inflammatory drug (NSAID) usage is associated with gastrointestinal inflammatory damage and aggravation of gut inflammatory conditions. NSAIDs also exert a preventive effect against colon cancer that seems to be due to increased colon cell apoptosis. NSAIDs have been shown to modulate the release of colony stimulating factors (CSFs) in some cells. In the present study we analysed the effect of these drugs on secretion of CSFs and apoptosis in human colon epithelial cells (HT-29). 2. HT-29 cells secreted bioactive levels of GM-CSF, G-CSF and M-CSF when stimulated with IL-1ss and TNF-alpha, and diclofenac (10(-7)-10(-4) M), indomethacin (10(-7)-10(-4) M) and sodium salicylate (10(-5)-10(-2) M) induced concentration-dependent increases in GM-CSF secretion. 3. Reduced secretion of G-CSF and M-CSF and increased cell apoptosis were observed with the highest concentrations of these non-selective NSAIDs. 4. No changes in any CSF release or HT-29 cell apoptosis were detected in the presence of the COX-2 selective inhibitor DFP (10(-7)-10(-4) M). 5. Neither the exogenous addition of CSFs nor the blockade of secreted CSFs modified apoptosis in HT-29 cells stimulated with cytokines and/or NSAIDs. 6. These results suggest that colon epithelial cells can contribute to local inflammatory responses by releasing CSFs and thus extend the life span of local leukocytes. Modulation of CSF levels by non-selective NSAIDs may be involved in the pro-inflammatory effects of these agents in the gut.