藏药湿生扁蕾提取物通过NF-κB通路诱导结肠癌细胞凋亡的机制研究

目的探讨藏药湿生扁蕾提取物通过NF-κB信号通路诱导结肠癌SW480细胞凋亡的作用及其机制。方法本研究用不同浓度的藏药湿生扁蕾提取物处理结肠癌SW480细胞,通过JC-1染色检测SW480细胞线粒体膜电位的变化,通过Hoechst染色以判断藏药湿生扁蕾提取物是否具有诱导结肠癌细胞SW480细胞凋亡效应。同时检测NF-κB蛋白的表达,用以明确NF-κB信号通路在结肠癌发生中的作用机制。结果经一定浓度的湿生扁蕾提取物处理后的SW480细胞内,NF-κB的表达明显下调,染色现象揭示湿生扁蕾提取物具有促进肿瘤细胞凋亡的作用。结论湿生扁蕾提取物可以在体外诱导肿瘤细胞凋亡,其抗肿瘤机制是通过NF-κB信号通路介导的。     

MCL-1 siRNA通过线粒体凋亡途径部分逆转耐顺铂结肠癌细胞系SW480的耐药性

目的 探讨顺铂耐药结肠癌细胞的MCL-1表达水平与顺铂耐药性的关系。方法 用MTT法检测顺铂耐药结肠癌细胞系SW480(SW480-R)对顺铂的敏感性。通过检测siRNA下调SW480-R 细胞MCL-1的表达作用观察其对细胞耐药性的影响。Western blot试验检测SW480-R 细胞Bcl-2家族蛋白及线粒体来源促凋亡因子的表达水平。Annexin V/PI染色检测SW480-R 细胞的凋亡。结果 SW480-R细胞相比于常规SW480细胞对顺铂的敏感性显著下降,western blot结果表明SW480-R细胞的MCL-1水平显著上调而其他Bcl-2蛋白家族成员(Bcl-2,Bcl-xl,BIM,BAK,BAX)表达水平变化不明显。体外转染MCL-1 siRNA能逆转SW480-R细胞的耐药性,提高顺铂对SW480-R的杀伤活性。在SW480-R细胞中,MCL-1 siRNA能促进线粒体来源的促凋亡因子(细胞色素C、凋亡诱导因子、Smac/DIABLO)在顺铂治疗下从线粒体中释放到细胞质中,进而诱导耐药肿瘤细胞发生凋亡。结论 MCL-1的高表达可能是结肠癌细胞产生顺铂耐药性的重要机制,MCL-1基因沉默能通过线粒体凋亡途径逆转耐顺铂结肠癌细胞系SW480的耐药性。     

槲皮素对结直肠癌细胞SW480增殖与Bcl-2、C-myc表达的影响

目的:研究槲皮素对结直肠癌细胞SW480增殖与B细胞淋巴瘤/白血病-2(Bcl-2)、癌基因C-myc表达的影响。方法:5、10、20、40、80、160μmol/L槲皮素处理SW480细胞后,采用MTT法检测SW480细胞增殖情况,计算细胞增殖抑制率;实时荧光定量反相聚合酶链反应(qRT-PCR)和Western blot法检测Bcl-2、C-myc mRNA和蛋白表达水平。结果:槲皮素对SW480细胞有明显抑制作用,能够诱导SW480细胞凋亡,且与剂量、时间呈正相关;40μmol/L槲皮素可明显抑制Bcl-2、C-myc mRNA的表达;处理48、72 h时40μmol/L槲皮素明显抑制Bcl-2、C-myc蛋白的表达(P<0.05)。结论:槲皮素能够抑制SW480细胞增殖,且呈时间-剂量依赖性,槲皮素可能通过下调Bcl-2、C-myc的表达水平而发挥抗结直肠癌作用。     

藏药湿生扁蕾提取物通过NF-κB通路诱导结肠癌细胞凋亡的机制研究

目的：探讨藏药湿生扁蕾提取物通过 NF －κB 信号通路诱导结肠癌 SW480细胞凋亡的作用及其机制。方法本研究用不同浓度的藏药湿生扁蕾提取物处理结肠癌 SW480细胞,通过 JC －1染色检测 SW480细胞线粒体膜电位的变化,通过 Hoechst 染色以判断藏药湿生扁蕾提取物是否具有诱导结肠癌细胞 SW480细胞凋亡效应。同时检测 NF －κB 蛋白的表达,用以明确 NF －κB 信号通路在结肠癌发生中的作用机制。结果经一定浓度的湿生扁蕾提取物处理后的 SW480细胞内,NF －κB 的表达明显下调,染色现象揭示湿生扁蕾提取物具有促进肿瘤细胞凋亡的作用。结论湿生扁蕾提取物可以在体外诱导肿瘤细胞凋亡,其抗肿瘤机制是通过 NF －κB 信号通路介导的。     

人参皂苷Rh2调控PI3K/AKT/GSK-3β信号通路诱导人结肠癌细胞凋亡

目的探究人参皂苷Rh2(ginsenoside Rh2,Rh2)诱导人结肠癌细胞SW480凋亡作用机制。方法 CCK-8法检测Rh2对SW480细胞增殖的影响;流式细胞术(Flow cyto Metry,FCM)检测Rh2对SW480细胞凋亡的影响;Hoechst33258染色观察Rh2对SW480细胞凋亡形态学的影响;Western blot检测经Rh2诱导SW480细胞中凋亡相关蛋白Bcl-2、Bax、p53、cleaved caspase-3,PI3K/AKT/GSK-3β信号通路相关蛋白PI3K、AKT、P-AKT、GSK-3β、P-GSK-3β表达量变化;LY294002、Rh2单独及联合诱导SW480细胞后,蛋白PI3K、AKT、P-AKT、GSK-3β、P-GSK-3β表达量变化。结果CCK-8结果显示Rh2呈时间浓度依赖抑制SW480细胞增殖。FCM结果显示细胞早期凋亡率由正常对照组的(0.70±0.09)%增至(11.06±1.04)%(P<0.05)。Hoechst33258结果显示,Rh2诱导SW480细胞48h后呈现典型的凋亡形态学改变。Western blot结果显示,经Rh2诱导的SW480细胞,凋亡相关蛋白Bcl-2表达降低,Bax、p53、激活型胱天蛋白酶3(cleaved caspase-3)蛋白表达增加;PI3K/AKT/GSK-3β信号通路蛋白PI3K、P-AKT、P-GSK-3β表达量与对照组比较明显减少,AKT、GSK-3β表达量无明显变化;LY294002、Rh2和LY294002与Rh2联合诱导SW480细胞后,总AKT蛋白和总GSK-3β蛋白表达量基本一致,LY294002与Rh2联合用药对SW480细胞中PI3K、P-AKT和P-GSK-3β的表达抑制作用较单独用药更加明显。结论Rh2可能是通过抑制PI3K/AKT/GSK-3β通路,激活p53信号通路,激活caspase-3,破坏Bcl-2/Bax比例,诱导结肠癌细胞SW480凋亡。     

雷公藤红素促进RIP1蛋白的去泛素化增强TNF-α对结肠癌细胞的凋亡诱导活性的研究

目的 探讨中药活性成分雷公藤红素对TNF-α体外抗结肠癌活性的影响并研究其机制。方法 用雷公藤红素联合TNF-α体外治疗结肠癌细胞系SW480,MTT法检测SW480细胞的细胞活力。SW480细胞用雷公藤红素联合TNF-α治疗后,Annexin V/PI染色法检测细胞的凋亡,Western blot法检测细胞caspase-8、caspase-9和caspase-3的活化和对CYLD蛋白表达的影响,并用免疫共沉淀法检测SW480细胞RIP1蛋白的泛素化水平。结果 雷公藤红素联合TNF-α对结肠癌细胞系SW480的细胞活力抑制率和凋亡诱导活性均显著高于雷公藤红素及TNF-α单治疗组。雷公藤红素联合TNF-α对SW480细胞caspase-8、caspase-9和caspase-3的活化显著高于雷公藤红素及TNF-α单治疗组,且两者联合治疗后,caspase-8的活化时间显著早于caspase-9和caspase-3。SW480细胞用雷公藤红素联合TNF-α治疗后,其RIP1蛋白的泛素化水平显著低于雷公藤红素及TNF-α单治疗组。进一步研究发现,雷公藤红素能显著诱导SW480细胞CYLD蛋白的表达,而TNF-α对CYLD的表达水平无影响,当用小干扰RNA沉默CYLD的表达后,雷公藤红素对TNF-α的协同效应丧失。结论 雷公藤红素通过促进RIP1蛋白的去泛素化增强TNF-α对结肠癌细胞的凋亡诱导活性。     

细胞粘附在结肠癌细胞系SW480多药耐药表型中的作用

目的探讨细胞粘附在结肠癌细胞系SW 480多药耐药表型中的作用。方法通过细胞粘附实验、四甲基偶氮唑盐实验（MTT法）、细胞内阿霉素的蓄积和潴留及Annexin V/PI染色法检测凋亡等检测粘附于层粘连蛋白（LN）的结肠癌细胞系SW 480的多药耐药性的改变。结果粘附于LN的SW 480细胞对化疗药物敏感性显著下降,化疗药物的IC50均显著升高,化疗药物诱导的凋亡指数明显减少 细胞内阿霉素的蓄积和潴留均明显减少,药物泵出率显著增加（P〈0.05）。结论结肠癌细胞SW 480与LN粘附后,可能提高了对药物转运的能力,导致化疗药物在肿瘤细胞内蓄积的减少 通过提高抗凋亡的能力,逃避化疗药物诱导的凋亡。     

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。     

姜黄素体内外逆转结肠癌的5-氟尿嘧啶耐药研究及机制探讨

摘要：目的 探究姜黄素在体内外对结肠癌5-氟尿嘧啶（5-FU）耐药的逆转作用及其相关机制。 方法 以SW480结肠癌细胞为亲代细胞,构建5-FU耐药细胞株SW480R,采用MTT法检测SW480R细胞的耐药指数以及不同浓度的姜黄素对SW480R细胞增殖能力的影响;流式细胞术检测姜黄素对SW480R细胞周期和凋亡的影响;Western blot检测姜黄素对SW480R细胞上皮-间充质转化（epithelial-mesenchymal transition, EMT）相关蛋白以及Wnt信号通路相关蛋白的影响;采用裸鼠移植瘤模型检测肿瘤体积变化情况,计算姜黄素的体内抑瘤率,Western blot检测肿瘤组织中相关蛋白变化。结果 SW480R的耐药指数为12.16,姜黄素能够剂量依赖性地抑制SW480R细胞的增殖,阻滞SW480R细胞周期于G0/G1期,以及诱导SW480R细胞凋亡;Western blot结果表明姜黄素能够在体内外抑制EMT和Wnt信号通路的活性;体内实验表明姜黄素能够有效抑制裸鼠移植瘤的生长。结论 姜黄素能够在体内外逆转结肠癌的5-FU耐药,其机制可能是通过调控Wnt信号通路从而抑制EMT的发生。     

二烯丙基二硫下调LIMK1抑制人结肠癌SW480细胞迁移与侵袭

目的研究二烯丙基二硫(diallyl disulfide,DADS)对人结肠癌SW480细胞LIMK1表达及迁移、侵袭能力的影响,阐明其抑制肿瘤细胞迁移和侵袭的分子机制。方法 RT-PCR、Western blot、免疫细胞化学检测DADS对SW480细胞LIMK1表达的作用;划痕愈合和侵袭实验检测DADS对SW480细胞迁移、侵袭能力的影响。结果 RT-PCR结果显示,与对照组相比,DADS处理SW480细胞后其LIMK1 mR-NA表达明显下调。免疫细胞化学检测发现LIMK1蛋白在人结肠癌SW480细胞中高表达,DADS作用后LIMK1蛋白表达明显下调。Western blot检测显示,DADS呈时间浓度依赖性下调SW480细胞LIMK1蛋白表达。划痕愈合实验结果显示,随着DADS浓度增高,细胞划痕距离增宽,表明DADS呈浓度依赖性抑制SW480细胞迁移能力。Transwell侵袭实验结果表明,随着DADS浓度增高,细胞穿膜数逐渐减少,表明DADS呈浓度依赖性抑制SW480细胞侵袭能力。结论 DADS下调LIMK1表达可抑制人结肠癌SW480细胞迁移、侵袭,DADS抑制人结肠癌SW480细胞迁移、侵袭的分子机制可能与降低LIMK1蛋白表达水平有关。     

Virosecurinine induces apoptosis by affecting Bcl-2 and Bax expression in human colon cancer SW480 cells

Virosecurinine, the major alkaloid isolated from Securinega suffruticosa Pall Rehd was found to exhibit growth inhibition and cytotoxicity against huaman colon cancer SW480 cells via the microculture tetrazolium (MTT) assay. Due to its greater cytotoxic potency and selectivity towards SW480 cells, flow cytometry was used to analyze the cell cycle distribution of control and treated SW480 cells whereas Annexin V-FITC/PI flow cytometry analysis was carried out to confirm apoptosis induced by virosecurinine in SW480 cells. Apoptotic regulatory genes were determined by RT-PCR analysis. Virosecurinine was found to induce G1/S cell cycle arrest which led to predominantly apoptotic mode of cell death. Mechanistically, virosecurinine was found to up-regulated the Bax gene expression and down-regulated the Bcl-2 expression in SW480, The ratio of Bcl-2 to Bax was significantly decreased. Hence, we suggest that virosecurinine induced apoptosis in SW480 cells by affecting the expression of bcl-2 and bax.     

Modification of the sensitivity to cisplatin with c-myc over-expression or down-regulation in colon cancer cells.

Human colon cancer SW480 cells express the c-myc gene. On the other hand, SW480DDP cell lines resistant to cisplatin exhibited decreased c-myc gene expression, but their cell growth rates remained similar to those of their parental cells. Antisense oligonucleotides to c-myc inhibited c-myc expression and induced increased resistance to cisplatin in SW480 cells. In contrast, SW480DDP cells showed increased c-myc expression and reversed sensitivity to cisplatin when these cells were transfected with c-myc cDNA from the pLNCX plasmid. Moreover, SW480DDP cells transfected with c-myc cDNA induced apoptosis when exposed to cisplatin, but not SW480 cells transfected with an antisense sequence for c-myc. Transfection either with a c-myc antisense sequence or c-myc cDNA to these cells did not change their growth rates. Thus enforced expression of c-myc in SW480 and SW620 lines sensitizes cells to cisplatin-induced apoptosis, whereas the down-regulation of c-myc in SW480DDP and SW620DDP increases cisplatin resistance when using antisense strategy.     

GST-TAT-P53c融合蛋白的表达及对p53基因突变型肿瘤细胞的促凋亡作用

目的研究P53蛋白C端(P53c)对p53基因突变型肿瘤细胞SW480的促凋亡作用。方法用人类免疫缺陷病毒TAT蛋白的蛋白转导域(TAT)将P53c运载进入肿瘤细胞,用氧依赖性降解区域(ODD)控制P53c在组织中的稳定性。通过PCR方法制备TAT-ODD-p53c(TOPc),TAT-p53c(TPc)及p53c基因,与pGEX4T载体连接后在大肠杆菌中表达谷胱甘肽-S-转移酶(GST)-TAT-ODD-P53c(GST-TOPc),GST-TAT-P53c(GST-TPc)及GST-P53c等融合蛋白。免疫组化方法检测TAT蛋白运载融合蛋白穿过SW480细胞膜的作用,MTT法检测融合蛋白对SW480细胞活力的影响,流式细胞仪检测致SW480细胞凋亡作用。结果成功构建pGEX系列表达载体,并在大肠杆菌中可溶性表达。Western印迹结果表明,重组蛋白可以和GST单克隆抗体特异性结合。免疫组化显示GST-TPc,GST-TOPcm及GST-TOPc均能进入SW480细胞,GST-TPc能明显降低SW480细胞活性,导致SW480细胞凋亡。含ODD的融合蛋白在常氧环境中对肿瘤细胞有轻度促凋亡作用。结论TAT可以介导其融合蛋白跨越细胞膜。GST-TPc可引起p53突变型肿瘤细胞凋亡。     

Indole-3-carbinol enhances anti-proliferative, but not anti-invasive effects of oxaliplatin in colorectal cancer cell lines

The primary aim of this study was to determine whether combination of the chemopreventive agent indole-3-carbinol (I3C) with oxaliplatin would decrease proliferative index and invasive potential of human colorectal tumour cells. Combination of the agents resulted in a 170-fold decrease in proliferative capacity in SW480 and SW620 cell lines, which was approximately 6-fold greater than for oxaliplatin alone. Decreased proliferation was attributed to enhanced S-phase cell cycle arrest for SW480, and increased apoptosis for SW620 cells. The combined agents resulted in significantly increased E-cadherin levels in SW480 cells, and beta-catenin levels in both cell lines (assessed by in-cell westerns). In SW480 cells confocal microscopy revealed an increase in membrane-associated beta-catenin levels, with oxaliplatin treatments enhancing nuclear export and cytoplasmic localisation. In SW620 cells, all treatments increased membrane localisation of E-cadherin. Whilst both oxaliplatin and I3C decreased invasive capacity of SW480 cells, this was not further enhanced by the combined treatment.     

Dietary flavanols exert different effects on antioxidant defenses and apoptosis/proliferation in Caco-2 and SW480 colon cancer cells

Flavanols intake has been associated with reduced risk of cancer. In this study, the anticarcinogenic effects of the flavanols epicatechin (EC), epicatechin-gallate (ECG) and procyanidin B2 (PB2) on Caco-2 and SW480 colon cancer cells were investigated. Catechins showed different cytotoxicity depending on the cell line. ECG displayed strong growth inhibitory effects against SW480 cells, but was ineffective on Caco-2 cells. In contrast, PB2 did not affect Caco-2 cells, whereas promoted cell growth in SW480 cells and EC had no obvious effects on any cell line. Exposure of SW480 cells to ECG led to apoptosis as determined by caspase-3 activity, imbalance among Bcl-2 anti- and pro-apoptotic protein levels, ERK activation and AKT inhibition, whereas PB2 treatment enhanced phospho-AKT and phospho-ERK levels. Incubation of Caco-2 cells with ECG increased glutathione levels without affecting the expression of pro- and anti-apoptotic Bcl-2 proteins, AKT or ERK. The results suggest that the different cytotoxicity of flavanols is caused by their different activity and the degree of differentiation of the colon cancer cell line. Thus, ECG induced apoptosis in SW480 cells and contributed to the cytotoxic effect, whereas ECG enhanced the antioxidant potential in Caco-2 cells. PB2 activated cell proliferation and survival/proliferation pathways in SW480 cells.