Effects of 5-Aza-CdR on Cell Proliferation of Breast Cancer Cell Line MDA-MB-435S and Expression of maspin Gene

The effects of 5-Aza-2＇-deoxycytidine （5-Aza-CdR） on the proliferation of MDA-MB-435S cells and the expression of tumor suppressor gene maspin were investigated. Human breast cancer cell line MDA-MB-435S was treated with 5 μmol/L 5-Aza-CdR, a specific demethylating agent for 0 to 8 days. The growth of MDA-MB-435S cells was observed by MTT assay before and after 5-Aza-CdR treatment, respectively. The expression of maspin mRNA was detected by reverse transcfiption-polymerase chain reaction （RT-PCR）. The cell cycle of MDA-MB-435S cells was analyzed by flow cytometry. The results showed that the growth of MDA-MB-435S cells treated with 5-Aza-CdR for 8 days was significantly suppressed as compared with the control groups, and the inhibition rate increased sharply from 5 day to 8 day （35.42% to 71.29%）. Flow cytometry showed that 5 μmol/L 5-Aza-CdR could induce G2/M cell cycle arrest and decrease the percentage of mitosis cell number in this cell line. Maspin mRNA was expressed in MDA-MB-435S cells after 5-Aza-CdR treatment, but it was weakly detectable before the treatment. It was concluded that Maspin gene might be transcriptional silencing by hypermethylation and the re-expression of maspin gene by 5-Aza-CdR can inhibit the proliferation and induce the G2/M arrest of MDA-MB-435S breast cancer cells.

Re-expression of RASSF1A by 5-Aza-CdR Induced Demethylation of the Promoter Region in Human Biliary Tract Carcinoma Cells

Hypermethylation of the promoter region is an important mean for the transcriptional repression of a number of cancer-associated genes, and over-expression and/or increased activity of DNA methyltransferase are considered to be the main cause of promoter hypermethylation. In order to further explore the epigenetic mechanism of tumor suppressor gene RASSF1A inactivation, 5-aza-2’-deoxycytidine (5-Aza-CdR), a DNA methyltransferase inhibitor, was used to treat the human biliary tract carcinoma cell line QBC-939 at the concentration of 5 μmol/L for 24 h in this study. Af- ter the chemical intervention with 5-Aza-CdR, the methylation status in the promoter region of RASSF1A gene was detected by methylation specific PCR (MS-PCR), and the expression alteration of RASSF1A mRNA and protein were observed by RT-PCR and Western Blot respectively. Following the treatment with 5-Aza-CdR, methylaiton status in the promoter region of RASSF1A gene was re- versed from methylation to unmethylation. A 280 bp DNA band which represented RASS1FA expres- sion at transcriptional level and a 40 kDa (1kDa=0.9921 ku) protein band which represented RASSF1A expression at protein level were detected by RT-PCR and Western Blot respectively in the experimental group cells and there were no corresponding bands in the control group cells. The ex- perimental results suggest that 5-Aza-CdR can induce demethylation in the promoter region of RASSF1A. It can also reverse epigenetic transcriptional silencing caused by DNA methylation and induce the re-expression of RASSF1A in QBC-939. This study also suggest that the mechanism of RASSF1A inactivation is very closely related to the methylation of the promoter region, which may provide a new epigenetic understanding for tumor related gene inactivation and the pathogenesis of biliary tract carcinoma.

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

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 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对乳腺癌MCF-7细胞增殖及抑癌基因RASSF2A表达的影响

目的研究5-氮-2′-脱氧胞苷（5-Aza-CdR）对乳腺癌MCF-7细胞增殖及抑癌基因RASSF2A表达的影响。方法用不同浓度的5-Aza-CdR处理MCF-7细胞12-96h,四甲基偶氮唑盐比色（MTT）法和流式细胞仪分别检测药物处理前后细胞的增殖活性和凋亡率;实时荧光定量PCR（RT-qPCR）法检测各阶段RASSF2A mRNA的表达水平,甲基化特异性PCR（MSP）观察该基因甲基化的改变。结果用1、5、10μmol/L 5-Aza-CdR处理MCF-7细胞24、48、72和96h后,细胞生长均受到抑制,呈时间和剂量依赖性。流式细胞仪分析表明,3种药物浓度处理细胞72h后凋亡率增加,5和10μmol/L组凋亡率分别为（25.5±3.5）%和（58.2±3.2）%,与对照组（13.4±2.0）%相比差异有统计学意义（P〈0.05）。RT-PCR检测显示,不同浓度药物处理MCF-7细胞后,RASSF2A mRNA表达水平随着药物浓度的增加而逐步上调;进一步MSP检测发现这些癌细胞中RASSF2A甲基化状态得到了不同程度的逆转。结论 5-Aza-CdR可通过逆转RASSF2A基因异常甲基化导致该基因表达上调来抑制MCF-7细胞增殖,RASSF2A是一个乳腺癌相关抑癌基因。

5-Aza-CdR抑制HepG2细胞DLK1基因表达及细胞生长

目的探讨去甲基化药物5-氮杂-2'-脱氧胞苷(5-Aza-CdR)对DLK1基因及肝癌细胞系HepG2增殖、侵袭的影响。方法不同浓度的5-Aza-CdR及PBS作用HepG2细胞后,RT-PCR、Western blot检测DLK1基因及蛋白的表达水平;MTT、Transwell和流式细胞术检测HepG2细胞的生长、侵袭力及细胞周期的变化。结果 HepG2细胞经5-Aza-CdR处理后,DLK1 mRNA、蛋白表达量降低;MTT试验显示细胞生长速度依5-Aza-CdR浓度出现不同程度减慢;流式结果表明G1期细胞减少,S期细胞增加,出现S期阻滞;Transwell证实侵袭能力显著降低(P<0.05)。结论去甲基化药物5-Aza-CdR能有效地抑制DLK1基因的表达,从而抑制肿瘤细胞HepG2生长、增殖、侵袭能力。

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.

5-Aza-CdR对人肺腺癌A549细胞及SHOX2基因甲基化的影响

目的观察5-氮杂-2’-脱氧胞苷酸(5-Aza-CdR)对人肺腺癌A549细胞以及short stature homeobox 2(SHOX2)基因甲基化水平的影响。方法不同浓度的5-Aza-CdR处理A549细胞24~72 h,MTT比色法和流式细胞术检测药物处理后细胞增殖、周期和凋亡的变化,同时应用甲基化特异性PCR(MSP)法检测药物作用后SHOX2基因甲基化状态的变化。结果 5-Aza-CdR呈浓度依赖性抑制A549细胞增殖(P<0.05或0.01),随着5-Aza-CdR作用浓度的增加S期细胞明显增多,而G1期细胞减少;5、10μmol/L 5-Aza-CdR组凋亡率分别为(26.53±1.87)%和(38.84±3.10)%,均显著高于对照组(11.35±0.37)%的凋亡率(P<0.05或0.01)。MSP结果显示随着5-Aza-CdR浓度的增加,SHOX2基因启动子的甲基化条带减弱,而非甲基化条带则增强。结论 5-Aza-CdR能通过去甲基化作用逆转SHOX2基因启动子的高甲基化状态,并促进细胞的增殖和凋亡。

5-Aza-cdR可能通过提高海马组织内NR2B磷酸化水平改善小鼠学习和记忆能力

目的研究5-氮杂-2′-脱氧胞苷(5-Aza-CdR)对小鼠在跳台实验中的学习和记忆能力及其海马组织中NR2B 1472位点的酪氨酸磷酸化(p-Y1472 NR2B)的影响。方法将小鼠随机分为对照组(control)和5-Aza-CdR处理组(5-Aza-CdR)。侧脑室内注射10μmol/L 5-Aza-CdR,通过跳台实验检测小鼠的行为、学习和记忆能力。采用real-time PCR检测小鼠海马组织中NR2B mRNA的表达;Western blot和免疫荧光检测小鼠海马组织NR2B和磷酸化NR2B-Y1472(p-Y1472 NR2B)的表达水平。结果5-Aza-CdR组小鼠在跳台实验中潜伏期增加,错误次数减少,学习和记忆能力明显提高(P<0.05),同时,小鼠海马组织中NR2B mRNA和蛋白的表达水平均无明显变化,NR2B-Y1472的磷酸化水平升高(P<0.05),CDK5活性降低(P<0.05)。CA1区和CA3区NR2B荧光强度无差异,而CA1区p-Y1472 NR2B显著升高(P<0.05)。结论5-Aza-CdR对学习和记忆能力的影响可能与海马中p-Y1472 NR2B磷酸化相关。

5-Aza-CdR对HT22小鼠海马神经元细胞中NR2B磷酸化的影响

目的:研究5-氮杂-2′-脱氧胞苷对HT22小鼠海马神经元细胞中NR2B 1472位点的酪氨酸磷酸化(p-Y1472 NR2B)的影响。方法:使用小鼠海马神经元细胞系HT22,对照组细胞用0.1%BSA处理,处理组细胞用10μmol/L 5-Aza-CdR处理。采用real time RT-PCR检测NR2B mRNA的表达;Western Blot检测NR2B和磷酸化NR2B-Y1472(p-Y1472 NR2B)的表达水平;MTS法检测细胞活力;流式细胞分析技术检测细胞周期。结果:HT22细胞在10μmol/L 5-Aza-CdR作用下,NR2B-Y1472的磷酸化水平升高,细胞活力下降,细胞周期受到阻滞。结论:5-Aza-CdR对小鼠行为记忆能力的影响可能与NR2B-Y1472磷酸化相关。

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′-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。

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’-CdR对K562细胞甲基化酶及miR-146a、miR-29b表达的影响

目的观察甲基化酶抑制剂5-Aza-2’-CdR作用后K562细胞中miR-146a及miR-29b的表达水平变化及DNMT1、DNMT3a、DNMT3b三种甲基化酶水平的改变。方法 MTT法检测5-Aza-2’-CdR作用于K562细胞时的IC50浓度。通过茎环引物法及荧光定量PCR的方法检测miRNAs以及甲基化酶的水平。结果 5-Aza-2’-CdR作用于K562细胞时的IC50浓度随药物作用的时间不同而异。药物作用后72h进行检测,凋亡细胞比例上升,miR-146a、miR-29b的水平较对照组升高,而DNMT1、DNMT3a、DNMT3b的水平与对照组相比呈降低的趋势,DNMT3a在11μM 5-Aza-2’-CdR处理72h后虽表现出了升高的趋势,但差异无统计学意义。结论 5-Aza-2’-CdR能促进K562细胞的凋亡,5-Aza-2’-CdR作用后miR-146a、miR-29b表现出了上升的趋势而三种甲基化酶表达水平有所降低。

DNA甲基化酶抑制剂5-Aza-CdR对人牙髓细胞增殖活性及矿化能力的影响

目的：研究DNA甲基化酶抑制剂5-氮杂脱氧胞苷（5-Aza-2＇-deoxycytidine,5-Aza-CdR）对人牙髓细胞（human dental pulp cells,hDPCs）增殖活性和矿化能力的影响.方法：以酶消化联合组织块法体外培养人牙髓细胞,取第3代细胞并随机分为常规培养组（对照组）、矿化诱导组、5-Aza-CdR组及5-Aza-CdR联合矿化诱导液组（联合组）；分别于培养不同时间后,采用CCK8法检测各组hDPCs细胞的增殖活性；碱性磷酸酶活性检测法以及茜素红矿化结节染色法观察各组hDPCs的矿化能力.结果：与对照组相比,矿化诱导组、5-Aza-CdR组及联合组在培养第3～7天时,hDPCs的增殖活性明显降低（P＜0.05）；第3～14天时,碱性磷酸酶活性明显升高（P＜0.05）.第14天时,除对照组外各组均有矿化结节形成,其中5-Aza-CdR组矿化结节较少,矿化诱导组及联合组可见大片矿化结节,特别是联合组,矿化结节的密度更大、颜色更深.结论：体外培养条件下,DNA甲基化酶抑制剂5-Aza-CdR可降低hDPCs的增殖活性,增强其矿化能力.

5-Aza-CdR对德保黑猪手工克隆重构胚胎体外发育效果的影响

为了探讨5-氮杂-2′-脱氧胞苷(5-Aza-CdR)对德保黑猪手工克隆(HMC)重构胚胎体外发育效果的影响,本研究分别从供体细胞和重构胚入手,比较了5个不同处理浓度(0、5、10、20和40nmol/L)5-Aza-CdR处理HMC重构胚的体外发育效果,筛选最佳处理浓度;在最佳浓度下比较5个不同处理时间(0、24、48、72和96h)对HMC重构胚的体外发育效果,筛选最佳处理时间;用4个不同浓度(0、0.25、0.5和1μmol/L)5-Aza-CdR结合最佳浓度和最佳时间处理供体和重构胚,比较其体外发育潜能。结果显示,与空白对照组相比,5、10、20和40nmol/L5-Aza-CdR处理72h对重构胚卵裂率均无显著差异(P>0.05),20nmol/L 5-Aza-CdR处理能显著提高重构胚的囊胚率(P<0.05),10和20nmol/L 5-Aza-CdR处理均能显著提高囊胚细胞数(P<0.05),其中以20nmol/L 5-AzaCdR效果最佳;与空白对照组相比,利用20nmol/L 5-Aza-CdR处理HMC重构胚72h能显著提高重构胚的囊胚率和囊胚细胞数(P<0.05),其余处理时间对重构胚卵裂率、囊胚率和囊胚细胞数均无显著影响(P>0.05);在囊胚的最佳处理浓度(20nmol/L)和最佳处理时间(72h)下,结合供体的4个处理浓度(0、0.25、0.5和1μmol/L),同时处理重构胚和供体,各处理组HMC重构胚的发育潜能均有提高,但效果均不显著(P>0.05),其中0.25～0.5μmol/L 5-Aza-CdR处理效果较佳。综上表明,适宜浓度(0.25～0.5μmol/L)的DNA甲基化酶抑制剂5-AzaCdR处理供体细胞72h并结合20nmol/L 5-Aza-CdR处理重构胚72h均能有效提高德保黑猪HMC重构胚胎的体外发育潜能,该结果可为今后研究德保黑猪HMC胚胎DNA甲基化调控机制提供参考。