Demethylation of the γ-synuclein gene CpG island in colorectal cancer and its clinical significance

Objective To explore the relationship between γ-synuclein gene expression and CpG island demethylation in colorectal cancer (CRC), and the relationship between the demethylation and clinicopathological factors of CRC. Methods The expression of γ-synuclein mRNA was examined in 30 pairs of tumor tissues and tumor-matched non-neoplastic adjacent tissues (NNAT) by RT-PCR.CRC cell lines including COLO205, LoVo, and SW480 were used and treated with a demethylating agent, 5-aza-2'-deoxycytidine (5-aza-C). Before and after the treatment, the expression of γ-synuclein mRNA in the cells was determined by RT-PCR, and bisulfite sequencing PCR was also used to analyze methylation status of CpG island. The methylation status of γ-synuclein was then examined in 67 CRC samples and 30 NNAT samples by nested methylation-specific PCR (NMSP) and real time methylationspecific PCR (real-time MSP). The relationship between the demethylation of γ-synuclein in CRC and clinicopathological factors was analyzed. Results The mean γ-synuclein mRNA expression was 0.66±0.34 in CRC samples, which was much higher than 0.45±0.26 in NNAT samples (P=0.011). 5-aza-C could induce expression and demethylation of γ-synuclein in COLO205, LoVo and SW480 cells. Γ-Synuclein gene was demethylated in 80.0%(24/30) of the CRC samples and 50.0%(15/30) of the NNAT samples.The demethylated status of γ-synuclein was much higher in CRC samples than that in NNAT samples (P=0.030), and was significantly correlated with clinical stage, lymph node involvement, and distant metastasis of CRC (P＜0.05). Conclusion The upregulation of γ-synuclein expression in CRC is primarily attributed to the demethylation of CpG island, which may be used as a marker for prognosis.     

结直肠癌γ-synuclein基因启动子CpG岛的去甲基化及其临床意义

目的 探讨结直肠癌中γ-synuclein基因的表达与启动子区CpG岛甲基化修饰之间的关系,以及γ-synuclein基因去甲基化水平与结直肠癌临床病理特征的关系.方法 采用半定量RT-PCR法检测30例结直肠癌和相应癌旁组织中γ-synuclein基因的表达及去甲基化试剂5-杂氮-2＇-脱氧胞苷（5-Aza-C）干预对结直肠癌细胞COLO205、LoVo和SW480的γ-synuclein基因表达的影响.采用亚硫酸氢盐修饰测序（BSP）法检测5-Aza-C处理前后CpG岛的甲基化情况.采用巢式甲基化PCR（NMSP）及实时荧光定量MSP法检测67例结直肠癌组织和30例相应癌旁组织中γ-synuclein基因的甲基化状态,并分析其与临床病理特征的关系.结果结直肠癌组织中γ-synuclein mRNA的表达水平0.66±0.34,高于相应癌旁组织的0.45±0.26,差异有统计学意义（P=0.011）.5-Aza-C处理后,COLO205、LoVo和SW480细胞γ-synuclein mRNA表达水平明显上升,同时γ-synuclein基因启动子区CpG岛的甲基化水平明显降低.80.0%（24/30）的结直肠癌组织和50.0%（15/30）的相应癌旁组织的γ-synuclein基因被去甲基化,结直肠癌组织中γ-synuclein基因去甲基化的趋势明显强于相应癌旁组织（P=0.030）.γ-synuclein基因的去甲基化水平与结直肠癌的淋巴结转移、临床病理分期及远处转移有关.结论 结直肠癌中γ-synuclein基因的上调表达与启动子区CpG岛的去甲基化状态有一定关联,γ-synuclein基因的去甲基化水平有望成为结直肠癌患者判断预后的潜在标志物.     

Effects of 5-Aza-2′-deoxycytidine and trichostatin A on P16, hMLH1 and MGMT genes and DNA methylation in human gastric cancer cells

、0.214±0.018和0.156±0.017,均P＜0.05).结论 启动子区DNA高甲基化是胃癌细胞中P16、hMLH1和MGMT基因失活的主要原因之一,5-Aza-dC单独应用及5-Aza-dC和TSA联合应用致胃癌细胞中P16、hMLH1和MGMT基因启动子去甲基化,从而使其重获表达.     

5-杂氮-2′-脱氧胞苷对前列腺癌PC-3细胞生物学行为的影响

目的 检测E-cadherin基因在激素非依赖性前列腺癌(HIPC)细胞上的表达及启动子CpG岛甲基化,探讨甲基化抑制剂5-杂氮-2′-脱氧胞苷(5-Aza-CdR)对HIPC细胞的影响及意义.方法 2.5、5.0、10.0 μmol/L的5-Aza-CdR处理PC-3细胞72h后,甲基化特异性聚合酶链反应(MSP)方法检测CpG岛甲基化改变,逆转录—聚合酶链反应(RT-PCR)方法检测E-cadherin mRNA变化,Westernblot方法检测E-cadherin蛋白变化,Transwell小室检测细胞侵袭性改变.结果 HIPC的E-cadherin启动子CpG岛甲基化呈阳性,基因表达缺失,细胞侵袭性明显.经5-Aza-CdR作用之后,CpG岛甲基化阳性明显减弱(P＜0.05),E-cadherin基因恢复表达(P＜0.05),PC-3细胞的侵袭性下降约59.68％,且与药物的浓度呈正相关.结论 5-Aza-CdR可逆转PC-3细胞E-cadherin启动子CpG岛的异常甲基化,诱导mRNA转录和蛋白的表达,并降低癌细胞的侵袭性.     

去甲基化剂5-氮杂-2''''-脱氧胞苷对胃癌细胞生物学行为的影响

目的:探讨去甲基化剂5氮杂2’脱氧胞苷(5AzaCdR)对胃癌细胞生物学行为的影响。方法:使用浓度5×106mol/L和105mol/L的5AzaCdR处理胃癌细胞株AGS、SGC7901、MKN28及MKN45。通过MTT、平板克隆实验观察处理前、后细胞的生长活性,RTPCR检测处理前、后抑癌基因RASSF1AmRNA表达的改变,并应用流式细胞仪进行细胞周期和凋亡率的分析。结果:4株胃癌细胞经不同浓度之5AzaCdR处理后,与对照组相比,生长速度出现不同程度减慢;实验组AGS细胞较对照组细胞克隆形成率显著降低(32.4%、28.5%比57.0%,P<0.01);5AzaCdR处理后,3株无RASSF1AmRNA表达的细胞(AGS、MKN28和SGC7901)均检出基因重新表达;处理前后4株胃癌细胞无明显G1期、G2/M期改变,AGS细胞凋亡率由0.6%增至18.6%和20.2%,MKN28细胞亦出现凋亡率由1.85%增至3.85%和6.61%。结论:去甲基化剂5AzaCdR对胃癌细胞生长周期无显著影响,可能系通过诱导抑癌基因再表达或凋亡等途径,间接抑制胃癌细胞的生长。     

5-氮杂-2'-脱氧胞苷联合多西紫杉醇对前列腺癌细胞系PC3恶性表型抑制作用的实验研究

目的:观察甲基化转移酶抑制剂5-氮杂-2'-脱氧胞苷(5-aza-2dc)联合多西紫杉醇(DT)对人前列腺癌(PCa)细胞系PC3细胞增殖、迁移、侵袭能力、细胞周期变化和细胞凋亡的影响,探讨上述两种药物联合应用对前列腺癌细胞的体外抗肿瘤效应。方法:实验分为对照组、5-aza-2dc组、DT组及5-aza-2dc和DT联合用药组,采用四甲基偶氮唑蓝(MTT)比色法、划痕损伤实验、细胞迁移实验分别观察5-aza-2dc和(或)DT对PC3细胞株增殖、迁移、侵袭能力的抑制效应,利用Annexin V-FITC/PI染色和流式细胞术检测其诱导肿瘤细胞凋亡的作用及其与细胞周期的关系。结果:5-aza-2dc组、DT组及联合用药组均能明显提高对PC3细胞的抑制率,降低细胞迁移距离,减少侵入下室的细胞(P<0.05),联合用药组作用更明显;对照组、5-aza-2dc组、DT组及联合用药组细胞凋亡率分别为(10.65±0.39)%、(16.60±0.67)%、(17.95±1.08)%、(22.98±1.18)%,各用药组均能明显提高细胞凋亡率,联合用药组作用更明显(P<0.05);联合用药组能明显减少G0/G1期细胞,增加G2/M期细胞(P<0.05)。结论:5-aza-2dc和DT单独及联合应用均能在体外细胞水平显著抑制PC3细胞的增殖、迁移和侵袭作用,诱导细胞凋亡,使细胞停滞于G2/M期,两药联合的作用比各单药作用大,5-aza-2dc和DT联合作用于PC3细胞具有协同作用,值得进一步研究。     

Impact of number of retrieved lymph nodes and lymph node ratio on the prognosis in patients with stage Ⅱ and Ⅲ colorectal cancer

Objective To discuss the impact of number of retrieved lymph nodes and lymph node ratio (LNR) on the prognosis in patients with stage Ⅱ and Ⅲ colorectal cancer.Methods Clinicopathological data of 507 patients with stage Ⅱ and Ⅲ colorectal cancer were analyzed retrospectively. Follow-up was available in all the patients. Results The total number of retrieved lymph nodes was 5801, of which 1122 had metastasis. There was a positive correlation between metastatic lymph nodes and retrieved lymph nodes (r=0. 171, P＜0.01). In stage Ⅱ colorectal cancer there was a significant difference in 5-year survival rate between patients with more than 12 lymph nodes retrieved and those with less than 12 lymph nodes retrieved (P＜0.01). LNR also affected the 5-year survival rate of patients with stage Ⅱ and Ⅲ colorectal cancer (P＜0.05). In patients with similar LNR, the 5-year survival rate differed significantly among different regions of lymph node metastasis(P＜0.05). LNR influenced the prognosis independent of the number of lymph nodes retrieved. Conclusions The number of retrieved lymph nodes is a prognostic factor for stage Ⅱ and Ⅲ colorectal cancer. More than 12 lymph nodes should be retrieved for better staging and prognosis. LNR is also a prognostic factor in stage Ⅱ and Ⅲ colorectal cancer. Regions of lymph nodes metastasis should be considered when evaluating the prognosis of patients using LNR.     

5-杂氮-2′-脱氧胞苷诱导肝癌细胞株癌/睾丸抗原基因表达的研究

目的探讨使用5杂氮2′脱氧胞苷(5DC)诱导肝癌细胞株癌/睾丸抗原(cancer/testis,CT)基因的可行性。方法使用5DC处理前后,用RTPCR方法检测肝癌细胞株QGY7703、HepG2215、HepG2、SMMC7721、HLE、BEL7402、Huh7、BEL7404中CT抗原基因MAGEA1、A3、A6和A10表达;Southern杂交检测细胞株基因组DNA去甲基化状态。结果CT抗原家族中MAGEA1在QGY7703、SMMC7721、BEL7402、HLE、BEL7404中表达,MAGEA3在HepG2、HLE中表达,MAGEA4和MAGEA10表达均为阴性,而MAGEA6表达均为阳性;使用5DC后,MAGEA4在QGY7703、HLE中出现表达,MAGEA10在HepG2和HLE出现表达。去甲基化后基因组DNA相对去甲基化程度明显升高(t=-4.966,P<0.01)。结论尽管5DC使肝癌细胞株基因组去甲基化程度明显升高,但不能有效地诱导CT抗原基因广泛表达。     

5-氮-2'-脱氧胞苷和曲古抑菌素诱导脾酪氨酸激酶基因去甲基化及转录和表达

目的 观察去甲基化药物(5-氮-2-脱氧胞苷)和组蛋白去乙酰化酶抑制剂(曲古抑菌素)对结直肠癌细胞HCT-15中脾酪氨酸激酶基因表达、细胞增殖和侵袭能力的影响.方法 应用2.5 μmol/L的5-氮-2-脱氧胞苷和1 μmol/L的曲古抑菌素分别或联合处理HCT-15细胞,通过甲基化特异性聚合酶联反应、逆转录.聚合酶链反应(RT-PCR)和蛋白印迹检测处理前后脾酪氨酸激酶的甲基化状态和表达;氚胸腺嘧啶掺入法和体外细胞侵袭试验研究去甲基化前后细胞增殖力和侵袭力的变化.结果 (1)5-氮-2-脱氧胞苷和曲古抑菌素可使脾酪氨酸激酶基因去甲基化而恢复表达,曲古抑菌素增强5-氮-2-脱氧胞苷的去甲基化作用;(2)与脾酪氨酸激酶失表达阴性对照组比较,5-氮-2-脱氧胞苷、曲古抑菌素和联合用药组及脾酪氨酸激酶稳定表达阳性对照组中细胞增殖力分别下降30%、25%、45%和54%;细胞侵袭力分别下降22%、27%、43%和64%.结论 5-氮-2-脱氧胞苷和曲古抑菌素可恢复甲基化脾酪氨酸激酶基因的重新表达,抑制细胞增殖,降低细胞侵袭和转移力.     

Expression and clinical significance of FPARγ and β-catenin in breast cancer

Objective To study the expression of peroxisome proliferator-activated receptor γ (PPARγ) and β-catenin in breast cancer, and their correlations with clinicopathological parameters and prognosis. Methods Tissue samples obtained from 70 patients with breast cancer and 20 patients with breast benign mass were immunohistochemically examined for the expression of PPARγ and p-catenin. Results Overexpression rate of PPARγ protein was 34. 3% in breast cancer, significantly lower than that in breast benign mass. Abnormal expression rate of β-catenin in breast cancer was 67. 1%. A significant negative-correlation was found between the expression of PPARγ and β-catenin (r=-0. 398,P<0.05 ). PPARγ expression was inversely associated with histologic grade, tumor size, axillary lymph node metastasis,TNM stage and Ki-67 expression (P<0. 05), while positively correlated with ER status and overall survival rate (P<0. 05). Abnormal β-catenin expression was positively associated with histologic grade, axillary lymph node metastasis and TNM stage (P<0. 05), while inversely correlated with overall survival rate (P<0.05). Conclusion PPARγ and β-catenin are correlated with development of breast carcinoma,suggesting that detection of PPARγ and β-catenin may be of value in evaluating the biological behaviors and the prognosis of breast cancer.     

Expression and clinical significance of FPARγ and β-catenin in breast cancer

Objective To study the expression of peroxisome proliferator-activated receptor γ (PPARγ) and β-catenin in breast cancer, and their correlations with clinicopathological parameters and prognosis. Methods Tissue samples obtained from 70 patients with breast cancer and 20 patients with breast benign mass were immunohistochemically examined for the expression of PPARγ and p-catenin. Results Overexpression rate of PPARγ protein was 34. 3% in breast cancer, significantly lower than that in breast benign mass. Abnormal expression rate of β-catenin in breast cancer was 67. 1%. A significant negative-correlation was found between the expression of PPARγ and β-catenin (r=-0. 398,P<0.05 ). PPARγ expression was inversely associated with histologic grade, tumor size, axillary lymph node metastasis,TNM stage and Ki-67 expression (P<0. 05), while positively correlated with ER status and overall survival rate (P<0. 05). Abnormal β-catenin expression was positively associated with histologic grade, axillary lymph node metastasis and TNM stage (P<0. 05), while inversely correlated with overall survival rate (P<0.05). Conclusion PPARγ and β-catenin are correlated with development of breast carcinoma,suggesting that detection of PPARγ and β-catenin may be of value in evaluating the biological behaviors and the prognosis of breast cancer.     

5-氮杂-2’-脱氧胞苷对MDA-MB-231乳腺癌细胞SLIT2基因去甲基化作用及细胞运动能力的影响

目的 观察5-氮杂-2’-脱氧胞苷( 5-Aza-dc)对恶性乳腺癌MDA-MB-231细胞Slit2启动子的去甲基化作用及细胞运动能力的影响.方法 用5、10、20 μmol/L 5-Aza-dc分别处理MDA-MB-231乳腺癌细胞;噻唑蓝(MTT)比色法筛选能够恢复MDA-MB-231细胞Slit2表达的5-Azadc最适浓度为10 μmol/L;逆转录-聚合酶链反应(RT-PCR)检测对照组和10μmol/L处理组Slit2mRNA的表达;划痕实验和趋化实验检测5-Aza-dc给药后,乳腺癌细胞的非定向与定向运动能力的变化;聚集实验检测5 -Aza-dc对MDA-MB-231细胞间黏附能力的影响.结果 在RT-PCR结果中,对照组和10 μmol/L 5-Aza-dc处理组Slit2/GAPDH的密度比值分别为0.630±0.042和1.307±0.057,表明5-Aza-dc可有效恢复乳腺癌MDA-MB-231细胞Slit2的表达(P＜0.05).体外趋化实验显示10 μmol/L 5-Aza-dc处理的MDA-MB-231细胞定向运动能力降低(P＜0.01),趋化凶子上皮生长因子(EGF)浓度为10 μg/L时实验组穿过膜的细胞数为49.46±2.92;对照组为99.44±2.54.伤口愈合实验发现10μmol/L 5-Aza-dc处理的MDA-MB-231细胞非定向运动能力降低(P＜0.05),24h时实验组运动的距离为(0.330±0.016) mm;对照组为(0.440±0.045) mm.聚集实验显示10 μmol/L 5-Aza-dc处理的MDA-MB-231细胞间黏附能力增加(P＜0.01),60 min时实验组聚集指数为0.300±0.028,对照组为0.600±0.034.结论 5-Aza-dc可以使MDA-MB-231乳腺癌细胞Slit2启动子区去甲基化,使Slit2基因表达升高,恢复其抑制肿瘤运动的能力.     

5-Aza-dC和TSA对胰腺癌Panc-1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-dC)及组蛋白去乙酰化酶抑制剂曲古菌素A(TSA)对胰腺癌Panc-1细胞系中TFPI-2基因甲基化水平及基因表达的影响。方法 Panc-1细胞经5-Aza-dC和TSA单独或联合处理后,应用甲基化特异性聚合酶链反应(MSP),逆转录聚合酶链反应(RT-PCR),蛋白印迹法(Western Blot)检测细胞TFPI-2基因启动子区甲基化状态和mRNA及蛋白表达情况。结果 Panc-1细胞经5-Aza-dC单独处理或与TSA联合处理后,TFPI-2基因启动子区高甲基化状态产生逆转,表现为非甲基化,原本不表达TFPI-2 mRNA及蛋白的Panc-1细胞重新表达,TFPI-2mRNA相对表达量为0.821±0.050和0.887±0.042,蛋白表达量为0.613±0.092和0.712±0.059,两者作用效果相似。经TSA单独处理的Panc-1细胞TFPI-2基因启动子区仍为异常高甲基化状态,原本不表达的TFPI-2基因未见重新表达。结论 Panc-1细胞中TFPI-2基因启动子区高甲基化可能是导致该基因失活的主要原因;5-Aza-dC单独作用或与...     

5-氮-2'-脱氧胞苷对膀胱癌T24细胞株RUNX3表达及生物学行为的影响

够通过逆转T24细胞RUNX3基因的异常甲基化,诱导该基因的重新表达而恢复其抑癌功能.     

5-氮杂-2’-脱氧胞苷对HepG2中SLIT2甲基化和细胞恶性表型影响的实验研究

目的评估5-氮杂-2’-脱氧胞苷（5-aza-2dc）对人肝癌细胞系HepG2中抑癌基因SLIT2甲基化状态和细胞增殖、迁移、侵袭和凋亡的影响,探讨SLIT2基因在肝癌中的作用及5-aza-2dc的体外抑制肝癌的效应。方法实验分为对照组和加药组,分别应用MSP、MTT、划痕实验、侵袭实验、AnnexinV—FITC／PI双染实验检测细胞中SLIT2基因的甲基化状态和细胞的增殖、迁移、侵袭、凋亡的变化。结果5-aza-2dc处理后,HepG2细胞株中SLIT2基因甲基化程度得到一定程度逆转,并呈现出剂量依赖性;划痕实验48h后,对照组肝癌细胞明显向划痕的中央迁移,而药物处理组肝癌细胞迁移受到抑制;侵袭实验24h后,加药组细胞的侵袭能力较对照组降低（P〈0．05）;AnnexinV．FITC／PI双染实验显示加药组细胞凋亡率显著增加（P〈0．01）。结论5-aza-2dc对HepG2细胞有抑制细胞增殖、促进凋亡及抑制细胞迁移和侵袭能力等作用,其中对抑制细胞迁移和侵袭的作用可能是通过逆转SILT2基因甲基化、恢复其表达来实现的。     

HIC-1基因在乳腺癌的表达及其对细胞增殖和凋亡的影响

目的:探讨癌高甲基化1(hypermethylated in cancer 1,HIC-1)基因在乳腺癌组织中的表达,以及恢复HIC-1基因表达对乳腺癌细胞增殖活力和凋亡的影响。方法:应用免疫组化方法测定乳腺癌组织芯片中80例癌组织的HIC-1蛋白表达,并分析其与临床病理的关系。应用甲基化特异性PCR法检测乳腺癌MDA-MB-231细胞中HIC-1基因启动子区域甲基化与基因表达的关系,5-氮杂-2′-脱氧胞苷(5-aza-2′-deoxycytidine,5-aza-CdR)抑制甲基化后细胞HIC-1的表达水平变化。应用CCK-8方法和流式细胞仪测定恢复细胞HIC-1表达对MDA-MB-231细胞增殖和凋亡的影响。结果:正常乳腺上皮组织HIC-1免疫组化染色呈强阳性,平均染色积分9.00±0,乳腺癌组织HIC-1染色明显降低,平均染色积分为4.58±1.22(P<0.001)。HIC-1的蛋白表达与病人年龄、发生部位以及是否出现淋巴结转移无关,但与肿瘤的组织学类型相关(P<0.05)。MDA-MB-231细胞HIC-1基因启动子区域呈完全甲基化,用5μM的5-aza-CdR处理后可抑制HIC-1基因启动子甲基化、恢复HIC-1表达,并呈现浓度依赖性。恢复HIC-1基因表达抑制MDA-MB-231细胞增殖活性,促进MDA-MB-231细胞凋亡(P<0.05)。结论:乳腺癌组织HIC蛋白表达和癌细胞HIC-1基因表达明显降低,去甲基化药物可恢复肿瘤细胞内HIC-1基因表达,从而达到抑制肿瘤细胞增殖并促进细胞凋亡的目的。     

Comparative study of oncologic outcomes after multivisceral resection for stage ⅡC colorectal cancer between inflammatory and malignant adhesion

Objective To evaluate the differences in oncologic outcomes between inflammatory adhesion and malignant adhesion in patients with stage Ⅱ C colorectal cancer after multivisceral resection(MVR). Methods A retrospective review was undertaken of 287 patients who underwent MVR for stage Ⅱ C CRC, 120 patients for stage Ⅱ B, and 140 patients for Ⅲ A. Patients were divided into two groups: inflammatory adhesion(IA) and malignant invasion(MI). Results There were 153 patients with colon cancer and 135 patients with rectal cancer in the stage Ⅱ C group. The overall survival was significantly lower in the MI group at 5 years (38.5% vs. 59.4%, P＜0.05). Stage ⅡC patients with IA had similar survival rate to the patients with stage Ⅱ B CRC. Compared to the MA group,patients with stage Ⅲ A CRC showed significant differences in 5 years overall survival rate. Univariate analysis showed that differentiation, adhesion pattern, and complication were significant prognostic factors for patients with colon cancer, while pathological characteristics, adhesion pattern, and differentiation were significant for rectal cancer. Conclusions MI is an adverse prognostic factor for patients with stage Ⅱ C CRC. T4 should be further classified according to the adhesion pattern.