5-aza-2’deoxycytidine联合trichostatin A抑制乳腺癌细胞增殖能力的研究

背景与目的:晚近报道应用DNA甲基转移酶抑制剂5-aza-2’deoxycytid ine(AZA)联合组蛋白去乙酰化酶抑制剂trichostatin A(TSA)作用于多种肿瘤,可以达到治疗肿瘤的目的。本文在此探讨通过AZA联合TSA作用,抑制乳腺癌细胞株增殖能力。方法:联合应用两种药物作用于肿瘤细胞,应用RT-PCR的方法检测MDA-MB-435细胞株p21和p27的mRNA转录水平的改变。通过W ST方法来检测乳腺癌细胞的增殖能力变化,将MDA-MB-435细胞根据药物处理共分四组:①对照组;②AZA+TSA组;③AZA+TSA+4-OH TAM组;④4-OH TAM组。并且采用流式细胞仪来分析肿瘤细胞周期分布的改变,将MDA-MB-435分成另外四组:①对照组;②AZA+TSA组;③AZA+TSA+E2组;④AZA+TSA+E2+4-OH TAM组。结果:TSA以及AZA联合应用能使肿瘤细胞MDA-MB-435的p27的mRNA水平增加,而p21mRNA水平略减弱。增殖分析的四个组中:AZA+TSA组细胞增殖能力减弱(P<0.01),同时出现细胞阻滞于S期,加入雌激素后细胞阻滞稍减弱。AZA+TSA+4-OH TAM组增殖能力进一步减弱(P<0.01)。4-OH TAM组增殖能力没有改变。细胞周期分析的四个组中:AZA+TSA组出现细胞阻滞于S期,AZA+TSA+E2组细胞阻滞稍减弱。AZA+TSA+E2+4-OH TAM组细胞阻滞再次提高。结论:两种药物联合应用能使得乳腺癌肿瘤细胞增殖能力下降,对于肿瘤细胞有一定抑制作用。

5-aza-2’-deoxycytidine重新激活MDA-MB-231乳腺癌细胞雌激素受体基因的表达

目的 探讨 5 AZA CdR重新激活MDA MB 2 3 1乳腺癌细胞雌激素受体基因的表达。方法 采用免疫组织化学的方法 ,对用浓度为 2mg/L的 5 AZA CdR处理MDA MB 2 3 1乳腺癌细胞前后和阳性对照MCF 7乳腺癌细胞雌激素受体基因的表达情况进行检测分析。结果 5 AZA CdR处理过的MDA MB 2 3 1乳腺癌细胞ER的阳性表达率明显增高 (P <0 .0 5 )。结论 5 AZA CdR可以重新激活MDA MB 2 3

Effect of 5-Aza-2’-deoxycytidine on immune-associated proteins in exosomes from hepatoma

AIM: To study the effect of 5-Aza-2’-deoxycytidine (5-Aza-CdR) on heat shock protein 70 (HSP70), human leucocyte antigen-Ⅰ (HLA-Ⅰ) and NY-ESO-1 proteins in exosomes produced by hepatoma cells, HepG2 and Hep3B. METHODS: Exosomes derived from HepG2 and Hep3B cells treated with or without 5-aza-CdR were isolated and purified by ultrafiltration centrifugation and sucrose gradient ultracentrifugation. The number of exosomes was counted under electron microscope. Concentration of proteins in exosomes was measured by bicinchoninic acid protein assay. Expression of HSP70, HLA-Ⅰ and NY-ESO-1 proteins in exosomes was detected by Western blotting and immunoelectron microscopy. mRNA expression of p53 gene was detected by reverse transcription polymerase chain reaction.RESULTS: The mRNA expression of p53 gene was increased in both hepatoma cell lines after treatment with 5-Aza-CdR. The number of exosomes and the concentration of total proteins in exosomes were increased signifi cantly after treatment with 5-aza-CdR (P < 0.05). After treatment with 5-Aza-CdR, immunoelectron microscopy and Western blotting showed that the HSP70, HLA-Ⅰ and NY-ESO-1 proteins were increased in exosomes produced by both hepatoma cell lines. CONCLUSION: 5-aza-CdR, an inhibitor of DNA methyltransferase, can increase exosomes produced by hepatoma cells and immune-associated protein component of exosomes, which may be mediated by p53 gene upregulation and 5-Aza-CdR demethylation.

5-Aza-2'-deoxycytidine inhibits retinoblastoma cell by reactivating epigenetically silenced RASSF1A gene

AIM: To investigate the effect of 5-Aza-2’-deoxycytidine(5-Aza-CdR),a DNA methyltransferase(DNMT) inhibitor,on the growth and survival of the Chinese retinoblastoma(RB) cell line HXO-RB44. ·METHODS: The DNA methylation status of the Ras association domain family(RASSF1A) promoter in the presence of 5-Aza-CdR at different concentrations was analyzed by methylation-specific polymerase chain reaction(MSP). RASSF1A mRNA and protein levels were measured by semiquantitative RT-PCR and immunohistochemistry staining,respectively,when cells were treated with 5.0μmol/L of 5-Aza-CdR. The effect of 5.0μmol/L 5-Aza-CdR on the proliferation and viability of HXO-RB44 cells was examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay and flow cytometry. ·RESULTS: 5-Aza-CdR efficiently induced cell cycle arrest at G0 /G1 and apoptotic death in HXO-RB44 cells. MSP analysis showed that unmethylated RASSF1A DNA increased and methylated RASSF1A decreased in a dose-dependent manner in a range of 0.5-5.0μmol/L 5-Aza-CdR. Accordingly,RASSF1A expression was reactivated at both mRNA and protein levels. Incubation time of 5-Aza-CdR treatment also functioned as a factor for the demethylation status of RASSF1A promoter DNA,with a plateau on day four. 5-Aza-CdR at 5.0μmol/L completely demethylated the RASSF1A promoter in HXORB44 cells on day four,and as a result,RASSF1A expression increased significantly from day 4 to day 7.·CONCLUSION: 5-Aza-CdR inhibits the growth of the HXO-RB44 RB cell line and induces apoptosis by demethylating the RASSF1A gene.

Inhibitory Effects of 5-Aza-2'-Deoxycytidine and Trichostatin A in Combination with p53-Expressing Adenovirus on Human Laryngocarcinoma Cells

Objective： To investigate the effects of 5-Aza-2＇-deoxycytidine （5-Aza-Cdr） and trichostatin A （TSA） combined with p53-expressing adenovirus （Ad-p53） on Hep-2 cell line in vivo and in vitro, in order to explore its possibility in biological treatment of laryngocarcinoma. Methods： Effects of 5-Aza-Cdr and TSA in combination with Ad-p53 on Hep-2 cell line in vivo were determined by Cell Counting Kit-8 （CCK-8） assay. The effect of drug combination was calculated by Jin＇s formula. Effects on the cell line in vitro were investigated by establishing the nude mice model. Results： 5-Aza-Cdr and TSA showed inhibitory effects on the proliferation of Hep-2 cells in dose- and time-dependent manner. Ad-p53 can inhibit the growth of Hep-2 cells in vivo and in vitro. However, the combination of epigenetic reagents （5-Aza-Cdr/TSA） and Ad-p53 was less effective than individual use of Ad-p53. 5-Aza-Cdr and Ad-p53 inhibited the growth of transplanted tumors and reduced the volume of tumors, and the tumor volume of Ad-p53 group was significantly smaller than that of the control group （P0.05）. Conclusion： Both epigenetic reagents （5-Aza-Cdr/TSA） and Ad-p53 can suppress cell proliferation on Hep-2 in vivo and in vitro and there may be some antagonistic mechanism between Ad-p53 and epigenetic reagents （5-Aza-Cdr/ TSA）.

5-Aza-CdR对裸鼠皮下移植瘤组织中甲状腺乳头状癌细胞自噬和凋亡的影响及其机制

目的:探讨5-氮杂-2'-脱氧胞苷(5-Aza-CdR)对裸鼠皮下移植瘤组织中TPC-1细胞自噬和凋亡的影响,并阐明其作用机制。方法:16只BALB/c雌性裸鼠右前腋下接种人甲状腺乳头状癌(PTC) TPC-1细胞建立移植瘤模型。成瘤后裸鼠随机分为对照组和实验组,每组8只,对照组裸鼠腹腔注射生理盐水,实验组裸鼠腹腔注射5-Aza-CdR,隔日给药1次,连续给药4周。观察2组裸鼠移植瘤生长情况,末次给药后处死裸鼠,称瘤体质量。HE染色观察2组裸鼠移植瘤组织病理形态表现,免疫组织化学染色检测2组裸鼠移植瘤组织中微管相关蛋白轻链3 (LC3)、B细胞淋巴瘤-2 (Bcl-2)和Bcl-2相关X蛋白(Bax)蛋白表达水平,实时荧光定量PCR (RT-qPCR)法和Western blotting法检测2组裸鼠移植瘤组织中LC3、Beclin-1、Bcl-2、Bax、细胞外信号调节激酶激酶(MEK)、细胞外信号调节激酶1 (ERK1)、细胞外信号调节激酶2 (ERK2)、磷酸化ERK1 (p-ERK1)、磷酸化ERK2(p-ERK2) mRNA和蛋白表达水平,并计算Bax/Bcl-2比值。结果:与对照组比较,实验组裸鼠移植瘤体积和质量明显降低(P<0.01)。对照组裸鼠癌细胞数量多,排列紧密,细胞形状不规则,细胞核染色清晰,细胞核大,细胞有重叠和分叶,可见明显的病理性核分裂象,符合PTC病理特点;实验组裸鼠癌细胞数目明显减少,排列稀疏,细胞核固缩且胞核不明显,结缔组织明显增多。与对照组比较,实验组裸鼠移植瘤组织中LC3B和Beclin-1 mRNA及蛋白表达水平明显升高(P<0.05),Bax/Bcl-2比值升高(P<0.05或P<0.01),MEK、ERK1/2及p-ERK1/2 mRNA和蛋白表达水平明显降低(P<0.05或P<0.01)。结结论论:5-Aza-CdR可抑制裸鼠皮下移植瘤组织中TPC-1细胞生长,诱导移植瘤细胞自噬并促进细胞凋亡,其机制可能与丝裂原活化蛋白激酶(MAPK)/MEK/细胞外信号调节激酶(ERK)信号通路抑制有关。

Comparative Evaluation of the Effects of 5-Aza-2'-deoxycytidine and Trichostatin A on Reactivation of hMLH1 in COC1/DDP Ovarian Cancer Cell Line

Objective： hMLH1 protein serves to detect the DNA damage caused by cisplatin （DDP） and destroys the cell. The absence of hMLH1 expression has been correlated with acquired resistance of ovarian cancer cells to platinum. The aim of this study was to determine the possible role of DNA methylation and histone H3 lysine 9 （H3-K9） acetylation on the loss of hMLH1 expression, and to evaluate the reversal effects of 5-Aza-2＇-deoxycytidine （5-Aza-dC） and Trichostatin A （TSA） on DDP-resistance in ovarian cancer cell lines. Methods： Two human ovarian cancer cell lines, COC1 and its DDP-resistant subline, COCI/DDP were cultured. The two cancer cells were treated with 5-Aza-dC or TSA. Using COC1 cells as a control, we used methylation-specific PCR （MSP） to analyze DNA methylation at hMLHI gene promoter, hMLH1 mRNA and protein expressions were analyzed by reverse transcriptase-polymerase chain reaction （RT-PCR） and Western blot. Chromatin immunoprecipitation assay （CHIP） was used to test the levels of histone H3-K9 acetylation at hMLH1 gene promoter. Results： In COC1 cells, there was no DNA methylation at hMLH1 gene promoter, while there were hMLH1 mRNA and protein expression. In COC1/DDP cells, there was DNA hypermethylation at hMLH1 gene promoter, while there was no hMLH1 mRNA or protein expression. The treatment with 5-Aza-dC resulted in DNA demethylation at the promoter region, as well as restoration of hMLH1 expression in COC1/DDP cells. The treatment with TSA had no effects on DNA demethylation or restoration of hMLH1 expression in COC1/DDP cells. Conclusion： Hypermethylation of DNA at the promoter is related to the silencing of hMLH1 in COC1/DDP ovarian cancer cells. DNA methylation at hMLH1 promoter could play a significant role in determining the sensitivity of ovarian cancer to DDP. The drug resistance mediated by methylation of hMLH1 could be overcome by 5-Aza-dC.

Effect of 5-Aza-2'-deoxycytidine on the expression of p16 in hepatocellular carcinoma cells in vitro

Objective: To study the effect of 5-Aza-2’ -deoxycytidine (5-Aza-cdR) on tumour suppressor gene p16 expres- sion in hepatocellular carcinoma cells. Method: Expression of pl6 mRNA and protein in hepatocellular carcinoma cell lines SMMC-7721 and HePG2 before and after treatment with 5-Aza-cdR were analyzed via reverse transcriptase polymerase chain reaction(RT-PCR) and immunohistochemistrty Results: The expression levels of p16 mRNA and protein were increased dramatically after treatment with 5-Aza-cdR. Conclusion: Our data show that, 5-Aza-2’ -deoxycytidine can increase the expression of pl6 gene both at transcription and translation. The findings suggested that 5-Aza-cdR may reactivate the pl6 gene by demethylation.

Gene Expression Profiling of Human Myeloid Leukemic MV4-11 Cells Treated with 5-Aza-2’-deoxycytidine

The pyrimidine analog, 5-aza-2’-deoxycytidine (5-aza-dC) is a DNA methyltransferase inhibitor that triggers DNA demethylation leading to the reactivation of epigenetically silenced tumor suppressor genes. To understand the shift in gene expression which mediates the beneficial 5-aza-dC effects in leukemia, we have treated human myeloid derived leukemic cells with 5-aza-dC. Target genes were identified first in MV4-11 cells using a genome-wide gene expression profiling assay to detect differences in treated and untreated cells. From this analysis six genes were identified (HOXA4, HOXD4, HOXA8, HOXD12, CD9 and RGS2) as being significantly different expressed after treatment. To validate microarray data, we performed quantitative PCR on these genes from multiple leukemic cells. The results suggest that these genes are epigenetically regulated indicating that dysregulation of HOXA4, HOXD4, HOXA8, HOXD12, CD9 and RGS2 expression may play an important role in establishing the malignant phenotype in AML.

STAT3介导甲基化抑制剂5-AZA-DC调控子痫前期滋养细胞凋亡、增殖、侵袭与迁移的作用及分析

目的探讨甲基转移酶抑制剂5-氮杂-2-脱氧胞苷(5-AZA-DC)对子痫前期滋养细胞凋亡、增殖、侵袭与迁移的调控。方法收集40例正常妊娠组产妇和40例子痫前期(PE)组产妇胎盘组织,采用分娩后胎盘HE染色,胎盘组织中全基因组甲基化测序(WGBS),体外培养HTR8/Svneo、JEG-3、JAR、BeWo滋养细胞株,分为空白对照组(Control组)、STAT3沉默组(shSTAT3组)、STAT3过表达组(STAT3^(OE)组)。应用5-AZA-DC处理,采用CCK8、流式细胞技术、Transwell侵袭和细胞划痕实验,检测滋养细胞凋亡、增殖、侵袭与迁移。采用t检验和单因素方差分析,对数据进行统计分析。结果(1)在胎盘组织中,与正常妊娠组相比,PE组血管腔变小,血管闭塞,血流量少,绒毛间质间纤维蛋白沉积,绒毛可见梗死、玻璃样变。WGBS检测出PE组甲基化水平显著增高,其中STAT3[(17.25±1.05)vs.(30.36±1.33),P<0.01]、PTEN[(13.33±0.71)vs.(23.05±1.17),P<0.02]、TSC2[(15.28±1.43)vs.(26.53±1.15),P<0.02]基因为甲基化差异显著基因,差异有统计学意义。(2)在细胞株中,与空白对照组相比,5-AZA-DC干预后滋养细胞凋亡减少、增殖上调、侵袭与迁移上调,差异有统计学意义。结论STAT3基因是引起子痫前期发病的重要基因,5-AZA-DC干预对子痫前期滋养细胞凋亡、增殖、侵袭与迁移作用和影响显著。5-AZA-DC可能成为介导表观遗传学治疗子痫前期的潜在药物。

5-Aza-CdR对非小细胞肺癌细胞株A549细胞TFPI-2基因甲基化水平及表达的影响

目的:探讨甲基化酶抑制剂5-氮杂-2′-脱氧胞苷(5-aza-2-deoxycytidine,5-Aza-CdR)对非小细胞肺癌(NSCLC)细胞株A549中抑癌基因组织因子途径抑制物2(TFPI-2)基因甲基化水平及基因表达的影响。方法:用不同浓度的5-Aza-CdR[(1、5、10)×10-6mol/L]处理肺癌细胞株A549细胞,不加药物(0 mol/L)作为对照组。药物处理72 h后,甲基化特异性PCR(MSP)检测A549细胞TFPI-2基因的甲基化状态;Real-time PCR技术检测A549细胞TFPI-2基因mRNA的表达;Western blot检测A549细胞TFPI-2蛋白的表达。结果:MSP检测到对照组A549细胞TFPI-2基因呈高甲基化状态,5-Aza-CdR处理异常甲基化得到逆转。Real-time PCR检测显示(0、1、5、10)×10-6mol/L的5-Aza-CdR处理A549细胞72 h后,相对mRNA表达水平分别为1±0、1.49±0.14、1.86±0.09、5.80±0.15(P<0.05),TFPI-2基因mRNA表达呈明显的上升趋势,且随着药物浓度增加而增加。Western blot分析结果显示,对照组与(1、5、10)×10-6mol/L的5-Aza-CdR组的TFPI-2蛋白表达相对水平分别为0.12±0.01、0.23±0.02、0.31±0.02、0.62±0.03(P<0.05)。结论:5-Aza-CdR能成功逆转肺癌A549细胞中TFPI-2基因的高甲基化状态,并恢复TFPI-2基因mRNA及蛋白的表达。

5-Aza-CdR对人结肠癌Caco-2细胞系P16基因甲基化状态及其生物学表型的影响

目的观察人结肠癌Caco-2细胞系P16基因启动子区甲基化状态,并探讨去甲基化制剂5-氮杂-2-脱氧胞苷(5-Aza-CdR)诱导高甲基化失活的P16基因重新表达的可能性及其对细胞生长的影响。方法用不同浓度的5-Aza-CdR处理Caco-2细胞系,MSP法检测用药前后P16基因的甲基化状态,RT-PCR方法检测P16基因mRNA表达。MTT法观察细胞生长速度,流式细胞仪检测细胞周期、细胞凋亡率。结果 P16基因在人结肠癌细胞系Caco-2中启动子区呈甲基化状态,经过5-Aza-CdR处理后,P16基因启动子区呈去甲基化状态,其mRNA重新表达。CpG岛去甲基化后能明显地抑制细胞的生长,诱导细胞凋亡,影响细胞周期分布,并具有良好的量效依赖关系。结论 5-Aza-CdR能够逆转P16基因甲基化状态,调控P16基因表达并有效地抑制肠癌细胞增殖。

干扰素α、5-AZA-CdR对白血病细胞HL-60和K562的作用

【目的】探讨细胞因子干扰素α(INFα)和甲基化抑制剂5-杂氮脱氧胞嘧啶核苷(5-AZA-CdR)对白血病细胞HL-60和K562的作用机制。【方法】1000U/mL INFα和不同剂量的5-AZA-CdR作用于HL-60和K562 48h,通过RT-PCR检测Xaf1和XIAP mRNA的表达,流式细胞技术检测Bcl-2家族成员、线粒体膜电位(Δψm)和细胞凋亡的情况。【结果】INFα和5-AZA-CdR使HL-60和K562 Xaf1 mRNA表达增加,且与5-AZA-CdR呈剂量依赖性,其中5-AZA-CdR(5μmol/L)的作用最明显;XIAP mRNA表达无变化。INFα使HL-60和K562 Bax表达增加,Bcl-2和Bcl-xl表达无改变;5-AZA-CdR降低HL-60 Bcl-2、Bcl-xl、Bax表达,增加K562 Bax表达,不影响K562 Bcl-2和Bcl-xl。INFα和5-AZA-CdR都能使线粒体膜电位降低、细胞凋亡增加。除细胞凋亡外INFα和5-AZA-CdR对HL-60和K562的Xaf1 mRNA、Bcl-2家族成员以及Δψm无协同作用。【结论】INFα和5-AZA-CdR促进HL-60和K562细胞凋亡,其作用机制可能与上调Xaf1 mRNA的表达,下调Bcl-2(Bcl-xl)/Bax和降低线粒体膜电位有关。

5-Aza-CdR对人肾癌OS-RC-2细胞生长及γ-连环蛋白表达的影响

目的:研究甲基化抑制剂5-氮杂-2′-脱氧胞苷(5-Aza-CdR)对人肾癌OS-RC-2细胞增殖、凋亡及γ-连环蛋白(γ-catenin)表达的影响。方法:使用不同浓度(10-7,10-6,10-5,10-4mol/L)的特异性DNA甲基转移酶抑制剂5-Aza-CdR处理OS-RC-2肾癌细胞株。MTT检测5-Aza-CdR对肾癌细胞株OS-RC-2的生长抑制作用。流式细胞仪检测5-Aza-CdR对OS-RC-2肾癌细胞株凋亡的影响。细胞免疫化学检测5-Aza-CdR处理OS-RC-2肾癌细胞株后γ-catenin表达的变化。结果:5-Aza-CdR明显抑制肾癌细胞的增殖,促进其凋亡,且与药物浓度及作用时间有关。药物处理后γ-连环蛋白表达增加。结论:γ-catenin蛋白表达受甲基化的抑制,提示5-Aza-CdR可使γ-catenin基因去甲基化而抑制肾癌OS-RC-2细胞株增殖,并促进其凋亡。

5-Aza-2′-dC通过上调DR4与DR5表达增加TRAIL诱导乳腺癌细胞凋亡的敏感性

目的探讨5-Aza-2′-dC增加肿瘤坏死因子相关凋亡诱导配体(TRAIL)诱导乳腺癌细胞凋亡敏感性的作用及其可能机制。方法 5μmol/L 5-Aza-2′-dC预处理细胞96 h,TRAIL(0,50,100,200 ng/mL)处理细胞12 h,MTT检测细胞增殖抑制率,Annexin V-FITC/PI法检测细胞凋亡,流式细胞技术检测TRAIL受体DR4及DR5的表达,Western blot检测caspase-8蛋白表达水平,Real-time PCR检测细胞DR4、DR5和caspase-8 mRNA表达。结果 5-Aza-2′-dC预处理组与对照组相比,TRAIL对细胞增殖抑制率和诱导凋亡率明显高于对照组(P<0.05)。5-Aza-2′-dC能增加细胞表面DR4和DR5表达,促进凋亡通路关键蛋白caspase-8活化。5-Aza-2′-dC在mRNA水平增加了DR4、DR5和caspase-8的表达。结论 5-Aza-2′-dC增加了TRAIL诱导乳腺癌细胞凋亡的敏感性,其可能机制是通过上调DR4、DR5和caspase-8表达实现。

5aza2dc联合化疗药物诱导骨肉瘤细胞凋亡的实验研究

目的:探讨氮杂脱氧胞苷(5aza2dc)联合化疗药物对骨肉瘤疗效的影响。方法:5aza2dc、阿霉素(DOX)及两药联用处理人骨肉瘤OS732细胞24h和48h,MTT法测试细胞毒性,倒置相差显微镜、透射电镜下形态学观察。结果:0.2μmol/L的5aza2dc与1PPC的DOX联合应用24h后,肿瘤抑制率明显高于单用药组(P<0.01)。联用48h见大量细胞脱落悬浮于培养液中。电镜观察可见核固缩、核染色质边集及凋亡小体。结论:骨肉瘤OS732细胞对5aza2dc不敏感。DOX增强OS732细胞对5aza2dc的敏感性。

5-Aza-CdR对胃癌细胞系BGC823生长及DAPK1基因甲基化的影响

目的观察5-氮杂-2-脱氧胞苷(5-Aza-CdR)对体外培养的胃癌BGC823细胞增生和凋亡的影响及其对此细胞中DAPK1基因的甲基化状态的影响。方法选择浓度为1×10-6的5-Aza-CdR处理体外培养的BGC823细胞后,用Annexin-v-FITC凋亡检测药物处理后细胞凋亡情况;MSP法检测用药前后细胞中Apaf-1基因的甲基化状态;RT-PCR法检测用药前后细胞中DAPK1的mRNA表达的变化。结果在药物作用24、48、72 h后细胞的凋亡率分别为5.83±0.53、9.23±0.58、15.34±0.90,较对照组明显增加(P<0.05)。DAPK1基因的甲基化状态得到了逆转,DAPK-1基因的mRNA表达得到增加。结论5-Aza-CdR对BGC823细胞具有增生抑制作用,并促进细胞凋亡。DAPK1基因表达情况与其甲基化状态的改变有关。

5'-Aza-CdR对HT-29和LoVo结直肠癌细胞株中CDX2基因甲基化状态、mRNA表达及蛋白表达的影响

目的:探讨甲基化酶抑制剂5'-氮杂-2'-脱氧胞苷(5'-Aza-2'-deoxycytidine,5'-Aza-CdR)对结直肠癌细胞株HT-29和LoVo中CDX2基因甲基化水平、mRNA及蛋白表达的影响.方法:用不同浓度5'-Aza-CdR处理结直肠癌细胞株HT-29和LoVo.应用TaqMan探针为基础的实时定量PCR(Methylight)方法、SYBR Green PCR方法及蛋白印迹实验(Western blot)检测药物处理前后HT-29和LoVo细胞中CDX2基因的甲基化状态、mRNA和蛋白表达.结果:Methylight检测HT-29和LoVo细胞中C D X2蛋白在药物作用异常甲基化未得到逆转;实时荧光定量PCR和Western blot检测到0.5、1.0、1.5μmol/L 5'-Aza-CdR处理后C D X2基因m R N A和蛋白重新表达,实时荧光定量PCR检测对照组和不同浓度实验组在HT-29细胞株mRNA相对表达量分别为1.000±0.000、0.973±0.024、1.014±0.019和1.094±0.020;在LoVo细胞株相对表达量分别为1.000±0.000、0.966±0.038、1.050±0.029和1.007±0.019.Western blot检测CDX2蛋白在对照组和不同浓度实验组中HT-29细胞株相对表达量分别为0.454±0.049、0.501±0.041、0.340±0.050和0.531±0.046;LoVo细胞株相对表达量分别为0.527±0.037、0.415±0.037、0.432±0.040和0.626±0.046.以上作用无时间、剂量依赖性,但CDX2基因mRNA在HT-29细胞株表达(F=25.146,P=0.000)和LoVo细胞株表达(F=5.470,P=0.024)具有统计学差异,C D X2蛋白表达在HT-29细胞株表达(F=9.700,P=0.005)和LoVo细胞株表达(F=17.701,P=0.001)亦具有统计学差异.结论:结直肠癌细胞株HT-29和LoVo中CDX2基因mRNA和蛋白表达不受中DNA甲基化的表观遗传修饰的调控.

5-aza-2’-deoxycitydine诱导胃癌细胞系TIMP3基因去甲基化和转录上调的实验性探讨

目的:研究人类胃癌细胞系中5-aza-2’-deoxycitydine诱导肿瘤抑制基因TIMP3mRNA和蛋白表达。方法:DNA甲基化抑制剂5-aza-2’-deoxycitydine处理人类胃癌细胞系SGC-7901。应用RT-PCR和Western-Blot方法检测TIMP3基因mRNA和蛋白表达。应用MSP分析TIMP3基因启动子甲基化状态。结果:5-aza-2’-deoxycitydine诱导TIMP3基因启动子去甲基化,上调TIMP3mRNA和蛋白表达。结论:甲基化异常是胃癌细胞TIMP3基因失活的原因之一,并可受去甲基化制剂调控表达。

5-aza-2'-deoxycitydine影响胃癌细胞MGC803对奥沙利铂敏感性及其机制

目的:探讨DNA甲基化抑制剂5-aza-2′-deoxycitydine(5-aza-dC)影响胃癌细胞MGC803对奥沙利铂(Oxaliplatin,OXA)的化疗敏感性,及其与Ⅱ相代谢解毒酶GSTP1表达的相关性。方法:5-aza-dC处理MGC803,RT-PCR和Western-Blot方法检测GSTP1基因mRNA和蛋白表达。MSP法分析GSTP1基因启动子区甲基化状态。MTT法检测药物敏感性。结果:5-aza-dC诱导GSTP1基因启动子去甲基化,上调GSTP1mRNA和蛋白表达,降低了MGC803细胞对OXA的敏感性,24h IC50值分别为对照组(13.15±1.7)μg/L、1μM 5-aza-dC处理组(24.54±2.1)μg/L、5μM 5-aza-dC处理组(30.81±1.3)μg/L及10μM 5-aza-dC处理组(51.72±1.6)μg/L,P值<0.01,差异有统计学意义。结论:5-3za-dC降低胃癌细胞对奥沙利铂的敏感性,其机制与增强GSTP1表达有关。