5-氮-2''-脱氧胞苷对结肠癌细胞生物学行为的影响

目的 检测去甲基化药物5-氮-2'-脱氧胞苷(5-aza-2'deoxycytidine,5-aza-dC)对结肠癌细胞株SW620、COL0205和HT29生物学行为的影响,并研究该药物对多个基因表达的影响.方法 5-aza-dC处理对各结肠癌细胞生长周期、凋亡、细胞迁移和侵袭能力的影响分别采用流式细胞术、Annexin V/Propidium Iodide法、细胞划痕实验和Transwell小室侵袭实验检测.采用RT-PCR法检测抑癌基因THBS1、TIMP3、RASSF1A和癌基因c-myc、c-fos、bax在5-aza-dC处理前后各结肠癌细胞株中的表达改变情况.结果 5-aza-dC处理后,3株结肠癌细胞的生长周期均明显阻滞于G2/M期,细胞凋亡率显著增加(P<0.05).划痕实验后72 h,对照组结肠癌细胞明显向划痕的中央迁移,而药物处理组结肠癌细胞迁移不明显.5-aza-dC处理后,结肠癌细胞的侵袭能力较未处理组降低(P<0.05).5-aza-dC可恢复结肠癌细胞中多个抑癌基冈的表达,但是对癌基因的表达没有影响.结论 5-aza-dC对结肠癌细胞有阻滞细胞生长周期、促进凋亡及抑制细胞迁移和侵袭能力等作用,该作用可能足通过恢复多个抑癌基因的表达来实现的.     

奥沙利铂对结肠癌SW480细胞迁移侵袭及细胞凋亡的影响

目的探讨奥沙利铂对结肠癌细胞SW480细胞的增殖、凋亡及迁移作用的影响。。方法体外培养结肠癌SW480细胞,加入不同浓度的奥沙利铂(5, 10, 20, 40μg/mL),分别培养0,24,48,72h后,平板克隆形成实验检测奥沙利铂对结肠癌SW480细胞生长能力的影响;细胞划痕实验观察实验处理前后SW480细胞的迁移能力的变化;Matrigel细胞侵袭实验检测奥沙利铂对恶性肿瘤细胞侵袭和转移的影响;Real-time PCR和Western blot验证Bcl2、Bax、Bcl-Xl、E-Cadherin等基因的表达水平。结果奥沙利铂降低结肠癌SW480细胞的克隆形成率,显著抑制细胞的迁移能力,但奥沙利铂对结肠癌SW480细胞的侵袭能力无抑制作用;下调原癌基因Bcl2和Bcl-Xl的表达水平、上调抑癌基因Bax的表达水平。结论奥沙利铂抑制SW480细胞增殖、促进凋亡与下调Bcl2/Bax比值相关。     

普鲁卡因抑制脂多糖诱导的结肠癌细胞肿瘤侵袭性的作用机制

目的探讨普鲁卡因抑制脂多糖诱导结肠癌细胞肿瘤侵袭性行为的调控及其机制。方法 CCK-8细胞活性实验检测不同浓度的普鲁卡因对结肠癌细胞活性的影响,Western blotting分析普鲁卡因对脂多糖结合蛋白表达水平的影响,划痕愈合实验检测普鲁卡因对结肠癌细胞迁移能力的影响,Transwell侵袭实验检测普鲁卡因对结肠癌细胞侵袭能力的影响。结果浓度为0.08 mg/m L的普鲁卡因对结肠癌细胞的活性影响情况最明显,差异有统计学意义(P0.05);浓度为0.08 mg/m L的普鲁卡因对脂多糖结合蛋白的表达水平抑制最明显,差异有统计学意义(P0.05);划痕愈合测定显示普鲁卡因可以直接抑制结肠癌细胞的运动能力;Transwell侵袭实验测定显示普鲁卡因可以直接抑制结肠癌细胞的侵袭能力,差异有统计学意义(P0.05)。结论普鲁卡因可以通过影响脂多糖诱导结肠癌细胞的迁移和侵袭,可作为化疗辅助药物,为探索结肠癌诊疗的分子机制和新的潜在治疗策略提供相应理论帮助,为结肠癌的临床治疗方式提供有效支持。     

敲低Runt相关转录因子2(Runx2)表达抑制结肠癌细胞生长和迁移

目的构建稳定低表达Runt相关转录因子2(Runx2)的HCT-8结肠癌细胞,检测对结肠癌细胞生长和迁移等生物学行为的影响。方法首先采用Western blot法检测Runx2在不同结肠癌细胞系中表达,确定HCT-8结肠癌细胞高表达Runx2;将含有Runx2的慢病毒短发卡RNA(shRNA)的干扰载体与慢病毒包装辅助质粒共转染人胚肾HEK293FT细胞后,收集病毒上清,感染HCT-8结肠癌细胞。经嘌呤霉素筛选后,获得慢病毒介导的Runx2 shRNA的稳定表达细胞,利用实时定量PCR和Western blot法检测Runx2的shRNA的干涉效果;用CCK-8法检测细胞增殖活性、平板克隆形成实验检测癌细胞生长、Transwell~(TM)侵袭实验和划痕愈合实验检测Runx2 shRNA转染对癌细胞侵袭和迁移的影响。结果建立了稳定敲低Runx2水平的HCT-8结肠癌细胞;敲低HCT-8细胞Runx2表达水平后,癌细胞的生长、侵袭和迁移受到明显抑制。结论敲低Runx2抑制结肠癌细胞的生长、侵袭和迁移。     

5-氮杂-2’-脱氧胞苷通过反转原钙黏蛋白10表达抑制人乳腺癌细胞系MDA-MB-231的侵袭和迁移

目的 探讨5-氮杂-2’-脱氧胞苷（5-Aza-CdR）诱导抑癌基因原钙黏蛋白10（PCDH10）重新表达对人乳腺癌细胞MDA-MB-231体外侵袭迁移能力的影响并初步探讨其机制。 方法 体外培养人乳腺癌细胞MDA-MB-231,设置对照组和5-Aza-CdR药物处理组,分别采用反转录聚合酶链反应（RT-PCR）检测PCDH10 mRNA 的表达水平;Transwell法和划痕实验检测细胞的侵袭迁移能力;Western blotting检测PCDH10、DNA甲基转移酶（DNMT）3A、DNMT3B、核因子（NF）-κB p65和基质金属蛋白酶（MMP）-2、MMP-9蛋白表达的变化。 结果 5-Aza-CdR能够反转PCDH10的mRNA和蛋白表达;PCDH10表达恢复后MDA-MB-231细胞的侵袭迁移能力受到抑制;Western blotting检测发现,MDA-MB-231细胞经5-Aza-CdR处理后DNMT3A、DNMT3B、NF-κB p65、MMP-2和MMP-9的表达下调。 结论 5-Aza-CdR可抑制MDA-MB-231细胞DNMT3A和DNMT3B的表达,使抑癌基因PCDH10表达恢复,从而通过阻滞NF-κB p65的活化,下调MMP-2和MMP-9表达而抑制乳腺癌细胞的侵袭转移。     

EphA2调控结直肠癌细胞耐药的初步研究

目的:探究Eph受体A2(Eph A2)在结直肠癌细胞化疗耐药中的作用及相关机制。方法:Western blot及real-time PCR检测人结肠癌细胞株Lo Vo及结肠癌耐药细胞株Lo Vo/5-FU中Eph A2的表达情况。转染Eph A2 siRNA干扰结肠癌耐药细胞株Lo Vo/5-FU中Eph A2的表达,CCK-8法检测细胞对化疗药物的敏感性,划痕实验及Transwell实验检测细胞迁移及侵袭能力的变化,Western blot检测上皮-间充质转化(EMT)及相关信号通路分子的蛋白水平。结果:耐药细胞株Lo Vo/5-FU中Eph A2的mRNA及蛋白表达水平均明显高于亲本细胞株(P0.05);并且在亲本细胞株Lo Vo中,Eph A2的蛋白表达水平随着5-FU浓度的增加有升高趋势。沉默Eph A2可降低结肠癌耐药细胞株Lo Vo/5-FU的细胞活力,增加其对化疗药物的敏感性,并抑制细胞的侵袭迁移;同时上调细胞中上皮细胞标志物E-cadherin和β-catenin的表达并下调间充质细胞标志物N-cadherin和vimentin的表达,可抑制结肠癌耐药细胞株Lo Vo/5-FU的EMT进程。此外,干扰Eph A2的表达之后,Notch和Snail的表达也明显降低。结论:沉默Eph A2可部分恢复结肠癌耐药细胞株Lo Vo/5-FU对化疗药物的敏感性,其机制可能与抑制细胞侵袭和迁移、同时通过Notch/Snail信号通路影响细胞的EMT进程有关。     

RNA干扰CD151基因对子宫颈癌细胞增殖和迁移的影响

目的观察RNA干扰(RNAi)介导的CD151基因沉默对子宫颈癌细胞生长、迁移及侵袭的影响。方法采用免疫组化EnVision法检测子宫颈鳞状细胞癌及慢性子宫颈炎组织中CD151蛋白的表达;设计并筛选抑制CD151 mRNA表达的siRNA序列,构建含有shRNA序列的质粒转染子宫颈癌细胞;采用Western blot法筛选稳定沉默CD151基因的子宫颈癌细胞株,用于后续的细胞增殖、周期、凋亡、迁移和侵袭实验。结果 CD151蛋白在子宫颈鳞状细胞癌组织中阳性;与空载体组及空白对照组相比,转染Psciencer2.0-shRNA-CD151重组质粒的子宫颈癌细胞CD151表达水平显著下降,细胞增殖活力明显降低,细胞周期被阻滞在G_1期,细胞凋亡显著增加,细胞迁移和侵袭能力亦受到明显抑制,差异有统计学意义(P均0.05)。结论通过RNAi介导的CD151基因沉默可明显抑制子宫颈癌细胞的生长及恶性生物学行为,CD151有望成为治疗子宫颈癌的潜在靶点。     

沉默Twist基因对胃癌BGC-823细胞上皮-间质转化的影响

目的探讨干扰Twist基因表达对胃癌细胞株BGC-823细胞上皮-间质转化的影响。方法采用干扰技术并构建质粒、生物信息学软件、qRT-PCR技术、划痕实验、Transwell实验和Western blot法对BGC-823细胞进行体外实验。结果 Twist在胃癌组织中的表达高于癌旁组织(P0.05),且与胃癌患者的预后呈负相关性(P0.05)。干扰Twist表达后,胃癌细胞株的迁移、侵袭能力减弱(P0.05);E-cadherin的相对表达量增高(P0.01),而N-cadherin的相对表达量降低(P0.05)。结论胃癌细胞株BGC-823中Twist的表达可促进胃癌细胞发生上皮-间质转化,Twist在胃癌发生发展中起癌基因的作用。     

羽扇豆醇联合miR-145-5p对前列腺癌细胞增殖与凋亡的影响

目的:探讨羽扇豆醇(lupeol)联合微小RNA-145-5p(miR-145-5p)对前列腺癌细胞株LNCaP增殖与凋亡的影响。方法:将hsa-miR-145-5p和lupeol作用于LNCaP细胞24、48和72 h后用MTT法检测细胞活力抑制率;PI单染流式细胞术检测细胞周期;annexin V/PI双染流式细胞术和TUNEL实验检测细胞凋亡;Transwell法检测细胞迁移和侵袭;划痕愈合实验检测细胞迁移能力;细胞集落形成实验计算集落形成抑制率。结果:细胞对照组、非特异性对照组和溶剂组未出现有效的LNCaP细胞活力抑制、迁移抑制和侵袭抑制,而hsa-miR-145-5p组和lupeol组细胞活力、迁移和侵袭受到显著抑制,并出现早期凋亡;联合用药(hsa-miR-145-5p+lupeol)组比单独用药组出现更有效的生长抑制作用。结论:hsa-miR-145-5p和lupeol均可抑制LNCaP细胞增殖、迁移和侵袭,并诱导体外早期凋亡;lupeol可增强hsa-miR-145-5p对LNCaP细胞的抑增殖和促凋亡作用。     

ELMO1在胃癌细胞侵袭和迁移中的作用

目的:探讨吞噬和细胞运动蛋白1(ELMO1)的表达在胃癌细胞侵袭和迁移中的作用和功能。方法:用Western blot和实时荧光定量PCR实验检测5种胃癌细胞和1种人正常胃黏膜上皮细胞ELMO1的蛋白和mRNA表达水平,并筛选出ELMO1表达量高的胃癌细胞株;用细胞转染实验沉默胃癌细胞株的ELMO1;用细胞划痕实验以及Trenswell小室迁移和侵袭实验检测抑制该基因的表达对胃癌细胞侵袭和迁移能力的影响。结果:胃癌细胞中ELMO1的表达量明显高于人正常胃黏膜上皮细胞(P0.01),其中SGC7901细胞的ELMO1表达量最高;在SGC7901细胞中ELMO1-siRNA可显著沉默ELMO1的表达(P0.05);沉默ELMO1可显著降低胃癌细胞侵袭和转移的能力(P0.01)。结论:ELMO1在胃癌细胞中高表达,并可促进胃癌细胞的侵袭和迁移。     

Effects of 5-aza-2′deoxycytidine on RECK gene expression and tumor invasion in salivary adenoid cystic carcinoma

Reversion-inducing cysteine-rich protein with kazal motifs (RECK), a novel tumor suppressor gene that negatively regulates matrix metalloproteinases (MMPs), is expressed in various normal human tissues but downregulated in several types of human tumors. The molecular mechanism for this downregulation and its biological significance in salivary adenoid cystic carcinoma (SACC) are unclear. In the present study, we investigated the effects of a DNA methyltransferase (DNMT) inhibitor, 5-aza-2′deoxycytidine (5-aza-dC), on the methylation status of the RECK gene and tumor invasion in SACC cell lines. Methylation-specific PCR (MSP), Western blot analysis, and quantitative real-time PCR were used to investigate the methylation status of the RECK gene and expression of RECK mRNA and protein in SACC cell lines. The invasive ability of SACC cells was examined by the Transwell migration assay. Promoter methylation was only found in the ACC-M cell line. Treatment of ACC-M cells with 5-aza-dC partially reversed the hypermethylation status of the RECK gene and significantly enhanced the expression of mRNA and protein, and 5-aza-dC significantly suppressed ACC-M cell invasive ability. Our findings showed that 5-aza-dC inhibited cancer cell invasion through the reversal of RECK gene hypermethylation, which might be a promising chemotherapy approach in SACC treatment.     

A novel epigenetic mechanism regulating hyaluronan production in pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is characterized by an abundant stroma enriched with hyaluronan (HA), a major component of extracellular matrix known to play a critical role in tumor progression. The mechanisms that regulate HA synthesis in PDAC are poorly understood. To investigate whether DNA methylation and HA production from PDAC cells are associated, we studied the effect of 5-aza-2′-deoxycitidine (5-aza-dC), an inhibitor of DNA methylation, or DNA methyltransferase 1 (DNMT1) knockdown by small interfering RNA, on the HA production from PDAC cells. HA production into the conditioned medium was evaluated in PDAC cells treated with 5-aza-dC or DNMT1 knockdown. mRNA expression of HA synthase (HAS) genes was investigated by real-time RT-PCR. Treatment of PDAC cells with 5-aza-dC led to a significant increase in the HA production (up to 2.5-fold increase) in all 4 cell lines tested. This enhanced HA production by 5-aza-dC treatment was accompanied by increased mRNA expression of HAS2 and HAS3. Furthermore, increased HA production and HAS2/HAS3 mRNA expression was also observed in PDAC cells by knockdown of DNMT1. These findings provide evidence, for the first time, that epigenetic mechanism is involved in the regulation of HA synthesis in PDAC cells.     

启动子DNA甲基化调节胃癌中PDX1基因表达

目的明确PDXl启动子DNA甲基化,探讨启动子甲基化对PDXl在胃癌中表达的调节作用。方法收集3例胃癌活检组织,免疫组化检测PDXl蛋白表达：吉西他滨处理3株胃癌细胞,RT—PCR检测不同药物剂量和作用时间下PDXlmRNA表达;构建PDXl报告基因,检测启动子活性及吉西他滨处理前后启动子活性的变化;甲基化特异性PCR（MSP）检测3株胃癌细胞和8对配对胃癌组织中PDXl启动子甲基化状态。结果免疫组化结果显示胃癌中PDXl表达低于正常胃黏膜;RT—PCR显示吉西他滨使PDXlmRNA重获表达,且随剂量和时间依赖性。F383有最强启动子活性,吉西他滨显著增加了PDXl启动子活性（P〈0．05）。F383在AGS、BCG823、SGC7901中呈DNA完全甲基化状态;87．5％的胃癌组织出现F383部分甲基化,12．5％出现完全甲基化。癌旁正常组织仅有37．5％出现F383部分甲基化,未出现完全甲基化,两者比较有显著性差异（P〈0．05）。结论PDXl启动子存在DNA高甲基化,抑制了胃癌中PDXl的表达。     

Methylation patterns of IGFBP7 in colon cancer cell lines are associated with levels of gene expression

Altered expression of insulin-like growth factor binding protein 7 (IGFBP7) has been found in colon cancer, but the exact regulatory mechanism has not been fully investigated. In order to elucidate the mechanisms underlying aberrant IGFBP7 expression in colon cancer, we used bisulphite sequencing PCR (BSP) to detect the detailed methylation profiles of the IGFBP7 5' CpG island. Exon 1 of the IGFBP7 gene was highly methylated in IGFBP7-negative cell lines but unmethylated in IGFBP7-positive lines. The methylation status of the promoter region and the intron 1 region was not so discriminating in IGFBP7-positive and -negative cell lines. Methylation-specific PCR (MSP) confirmed the hypermethylation of IGFBP7 exon 1 in IGFBP7-negative cell lines. Treatment with 5-aza-2'-deoxycytidine (5-aza-dC) induced demethylation of the CpG island in exon 1 of IGFBP7, as examined by both MSP and bisulphate genomic sequencing. Furthermore, the expression of IGFBP7 was restored, as detected by both RT-PCR and immunocytochemistry. Our study is the first to provide detailed methylation profiles of the IGFBP7 5' CpG island and shows that hypermethylation of the CpG island in exon 1 of IGFBP7 is closely related to the absence of its expression in colon cancer cells.     

结直肠癌中胰岛素样生长因子结合蛋白-相关蛋白1表达上调与其5′CpG岛低甲基化的相关性

目的 探讨胰岛素样生长因子结合蛋白-相关蛋白1(IGFBP-rP1)在结直肠癌中的表达改变并分析其与该基因5′CpG岛甲基化改变的关系.方法 采用半定量逆转录聚合酶链反应(RT-PCR)和甲基化特异性聚合酶链反应(MSP)检测46例结直肠癌组织和配对的正常黏膜中IGFBP-rP1基因的表达水平及5′CpG岛的甲基化状况,并通过T-A克隆、测序加以验证.不表达IGFBP-rP1基因的结肠癌细胞株LoVo和SW620经去甲基化药物5-氮-2′-脱氧胞苷(5-aza-2′-deoxycytidine,5-aza-dC)处理后,分别用RT-PCR和MSP检测IGFBP-rP1表达改变和甲基化状况.结果 mRNA水平上,IGFBP-rP1在结直肠癌组织中的表达水平高于配对的正常黏膜(P<0.01).在46例结直肠癌组织中,28例(60.9%)可检测到IGFBP-rP1基因5′CpG岛发生甲基化,而在配对的正常黏膜中,37例(80.4%)可检测到,二者差异有统计学意义(P<0.05).IGFBP-rP1基因的表达和甲基化水平之间存在负相关(P<0.05).5-aza-dC处理后,两株细胞均出现IGFBP-rP1基因的再表达,MSP法检测证实基因发生了去甲基化.结论 IGFBP-rP1基因的表达水平与5′CpG岛甲基化水平之间存在负相关.DNA甲基化是结直肠癌中IGFBP-rP1表达调控的一种机制.IGFBP-rP1低甲基化引起的基因表达上调可能与结直肠癌的发生发展有关.     

HBV X siRNA与5-氮-2'-脱氧胞苷对裸鼠肝癌皮下移植瘤作用的研究

目的 目的 探讨靶向HBV X的siRNA(X-siRNA)和5-氮-2′-脱氧胞苷(5-aza-dC)对HBV相关肝细胞癌生长的影响及可能机制.方法 设计合成X-siRNA及对照siRNA,用siRNA处理HepG2/GFP-HBx细胞,RT-PCR法测定处理细胞的HBV X基因表达;将HepG2/GFP、HepG2/GFP-HBx细胞接种于裸鼠皮下建立裸鼠肝癌皮下移植瘤,分别用X-siRNA、5-aza-dC单独或联合处理裸鼠并观察移植瘤生长;甲基化PCR测定移植瘤组织p16基因甲基化.结果 RT-PCR检测示X-siRNA处理的细胞HBV X mRNA水平明显降低;裸鼠体内实验显示HepG2/GFP-HBx组的皮下移植瘤体积明显大于HepG2/GFP组(P＜0.05);X-siRNA与5-aza-dC处理组移植瘤体积明显小于未处理组(P＜0.05);甲基化PCR检测示HepG2/GFP-HBx组移植瘤组织存在p16甲基化而HepG2/GFP组未检出p16甲基化;X-siRNA、5-aza-dC处理的移植瘤组织中p16基因甲基化减低.结论 X-siRNA及甲基化抑制剂可能通过逆转p16甲基化而能有效抑制肝细胞癌生长,具有潜在应用价值.     

DNA methylation dominates transcriptional silencing of Pax5 in terminally differentiated B cell lines

Pax5 plays a key role in the progression of B cell development. Its expression is observed in a wide range of cell types from early lineage-committed precursors up to mature B cells, but is silenced in terminal differentiated plasma cells. In this report, we show that DNA methylation is involved in the silencing of Pax5. In the Pax5-expressing cell lines 38B9 (pre-B) and 2PK-3 (mature B), all CpG sites in TATA-containing upstream promoter were unmethylated, whereas these sites were completely methylated in myeloma cell lines FO and Sp-2/0, which do not express Pax5. Demethylation of FO and Sp-2/0 with 5-aza-2'-deoxycytidine (5-aza-dC) resulted in Pax5 re-expression with the concomitant expression of CD19 and mb-1 genes, which are known to be the target genes of Pax5. Re-expression of Pax5 was also induced by trichostatin A (TSA), which was a specific inhibitor of histone deacetylase. This re-expression was, however, transcribed only from the TATA-less downstream promoter. Taken together, we concluded that the upstream promoter was predominantly inactivated by DNA methylation, while the downstream promoter was repressed by the histone deacetylation. This synergetic inactivation of two promoters results in the final silencing of Pax5 expression in terminally differentiated B cell lines.     

DNA promoter hypermethylation contributes to down-regulation of galactocerebrosidase gene in lung and head and neck cancers

Galactocerebrosidase (GALC) is a lysosomal enzyme responsible for glycosphingolipids degradation byproducts of which are important for synthesis of apoptosis mediator ceramide. Reduced expression of GALC has been identified in human malignancies; however, molecular mechanisms underlying down-regulation of GALC expression in cancer remain unknown. We performed methylation and expression analysis on GALC gene in a panel of head and neck cancer (HNC) and lung cancer cell lines, attempting to understand the regulation of GALC in human cancer. QRT-PCR and western blot analysis were performed to detect the expression of GALC in HNC. Bisulfite DNA sequencing and real-time qMSP were used to detect the methylation of GALC in HNC and lung cancer cell lines. 5aza-dC treatment assay was used to analysis the functional effect of GALC methylation on GALC expression in HNC. Reduction or complete absence of GALC expression was observed in more than a half of the tested HNC cell lines (8/14). 7 out of 8 cell lines with down-regulated expression harbored heavy CpG island methylation, while all cell lines with abundant expression of the gene contained no methylation. Hypermethylation was also found in primary HNC tumor tissues and lung cancer cell lines whereas absent in normal oral mucosa tissues. Demethylating treatment demonstrated that 5aza-dC significantly restored GALC expression in cell lines with methylated promoter while showed no effect on cell lines without promoter hypermethylation. Our findings for the first time demonstrated that promoter hypermethylation contributed to down-regulation of GALC Gene, implicating epigenetic inactivation of GALC may play a role in tumorigenesis of cancer.