乳腺癌发生过程中NOEY2基因启动子区甲基化及mRNA表达

目的 探讨乳腺癌发生过程中抑癌基因NOEY2启动子区甲基化状态及其对mRNA表达的影响。方法 应用甲基化特异性PCR及双亚硫酸钠基因测序技术检测MCF10模型中乳腺增生细胞系MCF10A、癌前细胞系MCF10AT、导管内癌细胞系MCFIODCIS．com、浸润癌细胞系MCF10CA1a、MCF10CA1d、MCF10CA1h及正常乳腺组织中NOEY2基因启动子区CpG岛Ⅰ甲基化状态,然后用RT-PCR和实时PCR技术检测上述样品的mRNA表达水平。结果 MCF10模型的增生细胞系、癌前细胞系、导管内癌细胞系、浸润癌细胞系均发生该基因启动子区CpG岛Ⅰ高度甲基化;与正常乳腺组织相比,上述细胞系mRNA表达显著减少。结论 NOEY2基因启动子区高度甲基化及相应的mRNA表达减少是乳腺癌发生过程中的早期事件,与乳腺癌发生有关,可能成为早期诊断乳腺癌的潜在分子生物学标记。     

乳腺癌发生模型MCF10各细胞系中WT1基因启动子区甲基化及mRNA表达研究

目的通过观察乳腺癌发生模型MCF10中WT1基因启动子区甲基化状态和mRNA表达水平,探讨该基因在乳腺癌发生中的作用。方法应用甲基化特异性PCR及双亚硫酸钠基因测序技术检测MCF10模型的乳腺增生细胞系MCF10A、癌前细胞系MCF10AT、导管内癌细胞系MCF10DCIS．com、浸润癌细胞系（MCF10CAla、MCF10CA1d、MCF10CA1h）、经典乳腺癌细胞系MCF7及正常乳腺组织中WT1基因启动子区甲基化状态,然后用逆转录．聚合酶链反应（RT—PCR）和即时定量PCR技术检测上述样品的mRNA表达水平。结果在MCF10模型的增生细胞系MCF10A、癌前细胞系MCF10AT、导管内癌细胞系MCF10DCIS．com、浸润癌细胞系（MCF10CAla、MCF10CA1d、MCF10CA1h）、经典乳腺癌细胞系MCF7中,WT1基因启动子均处于高度甲基化状态。与正常乳腺组织相比,WT1基因mRNA在MCFl0模型的增生细胞系、癌前细胞系、导管内癌细胞系、浸润癌细胞系和经典乳腺癌细胞系MCF7中的表达均有不同程度的增加（MCF10A、MCF10AT、MCF10CAla、MCF10CA1d、MCF10CA1h、MCF10DCIS、MCF7的WT1基因mRNA表达量分别是正常乳腺组织3．23、1．94、4．20、1．53、4．20、4．35、28．69倍）。结论乳腺癌发生过程中WnmRNA的表达不被启动子甲基化所抑制;可WT1mRNA过表达出现于乳腺癌发生的早期阶段,提示该基因在乳腺癌发生中起作用。     

乳腺癌发生模型MCF10各细胞系中APC基因启动子区甲基化及mRNA表达检测

目的探讨乳腺癌发生模型MCF10中抑癌基因APC启动子区甲基化状态及其对mRNA表达的影响。方法应用甲基化特异性聚合酶链反应（MSP）及双亚硫酸钠基因测序技术检测MCF10模型的乳腺增生细胞系MCF10A、癌前细胞系MCF10AT、导管内癌细胞系MCF10DCIS.com、浸润癌细胞系MCF10CA1a、MCF10CA1d、MCF10CA1h及经典乳腺癌细胞系MCF-7和正常乳腺组织中APC基因启动子1A甲基化状态,然后用逆转录聚合酶链反应（RT-PCR）和实时PCR技术检测上述样品的mRNA表达水平。结果在MCF10模型的增生细胞系、癌前细胞系、导管内癌细胞系、浸润癌细胞系中,APC基因启动子1A处于低甲基化状态;与正常乳腺组织相比,各细胞系APC基因mRNA表达无明显减少,MCF10AT、MCF10CA1d、MCF10CA1h、MCF10DCIS．com的mRNA表达分别减少0．27、0．96、1．78、2．70、2．03倍,MCF10A和MCF-7分别增加0．02和0．33倍）。结论MCF10模型中乳腺癌的发生发展过程与APC基因启动子区异常甲基化无关。     

散发性乳腺癌及乳腺不典型导管增生组织BRCA1基因启动子区甲基化分析

目的 了解散发性乳腺癌及癌旁增生组织、乳腺不典型导管增生组织BRCA1基因启动子区甲基化状态,探讨其与乳腺癌发生的关系.方法 采用甲基化特异性PCR(MSP)结合巢式PCR技术,研究23例散发性乳腺癌及其癌旁增生组织、6例乳腺不典型导管增生组织及5例健康成人女性外周血淋巴细胞中BRCA1基因启动子区甲基化状态.结果 5例健康成人女性外周血淋巴细胞均表现BRCA1基因启动子区甲基化阴性;23例原发性乳腺癌组织中,BRCA1基因启动子区CpG岛甲基化率为65.22%(15/23);癌旁增生组织检出CpG岛甲基化者11例,甲基化率为47.83%(11/23),且均为癌组织阳性患者;6例乳腺不典型导管增生组织中,BRCA1基因启动子区CpG岛甲基化阳性者2例,甲基化率为33.33%(2/6);统计学检验结果表明,乳腺癌、癌旁增生组织之间,BRCA1基因启动子区甲基化阳性率无显著差异.结论 BRCA1基因启动子区CpG 岛甲基化是散发性乳腺癌发生过程中的早期事件,可能在乳腺癌发生中和乳腺增生病癌变过程中起重要生物学作用.     

食管鳞癌分泌素-3A1基因启动子甲基化异常

[目的]研究具有抗癌活性的细胞因子分泌素-3A1基因启动子超甲基化所至该基因表达抑制在我国食管鳞癌发生中的作用。[方法] 用RT-PCR 方法检测分泌素-3A1基因在12个食管鳞癌细胞系的表达,并用甲基化特异PCR技术（methylation specific PCR, MSP）检测上述细胞系及37例来自我国河南的原发性食管鳞癌标本分泌素-3A1基因启动子甲基化状态,通过5-aza-dc处理使培养细胞去甲基化,RT-PCR技术检测处理后该基因在Kyse30的重新表达。[结果] 该基因仅在Kyse410、Kyes520和TE8等3个细胞系有表达,5-aza-dc处理可使Kyse30重新表达分泌素-3A1。此外,在18/37（48%）例原发性食管鳞癌细胞有分泌素-3A1基因启动子区域的超甲基化。[结论] 启动子超甲基化造成分泌素-3A1基因在上述食管鳞癌细胞系表达抑制,原发性食管鳞癌细胞分泌素-3A1基因启动子超甲基化提示该基因表达抑制可能与食管鳞癌发生有关。     

乳腺癌发生模型MCF10 抑癌基因NOEY2启动子区甲基化及mRNA表达

DNA甲基化是常见的表观遗传学变化。越来越多的证据表明,抑癌基因启动子区CpG岛甲基化可使其转录沉默,从而解除其抑癌作用,导致肿瘤的发生和发展。NOEY2是近年来发现的抑癌基因,表达于正常乳腺导管上皮细胞和卵巢生发上皮细胞,但在乳腺癌和卵巢癌细胞中表达显著减少或不表达。在本实验中检测乳腺癌发生模型MCF10中不同阶段的细胞系NOEY2基因启动子区CpG岛Ⅰ甲基化状态,并与mRNA表达水平进行比较,以研究乳腺癌的发生机制和早期诊断。     

乳腺癌细胞中PELP1基因表达与启动子区CpG岛甲基化相关性

目的建立针对PELP1基因启动子区CpG岛的甲基化特异性PCR(Methylation specific PCR,MSP)检测方法,分析乳腺癌细胞中PELP1基因表达与启动区CpG岛甲基化的相关性。方法设计针对PELP1基因启动子区的MSP引物组,以甲基化和非甲基化DNA为模板验证MSP引物的特异性,建立针对PELP1基因启动子区的MSP检测方法。以DNA甲基转移酶抑制剂5'-氮杂-脱氧胞苷磷酸(5'-Aza-d C)分别处理MCF-7乳腺癌细胞、MCF-10正常乳腺导管上皮细胞,采用MSP检测PELP1基因启动子区甲基化状态变化,采用Western blot检测蛋白表达。结果针对PELP1基因启动子区设计的MSP引物组特异性良好,甲基化特异性引物仅在甲基化DNA模板获得阳性扩增条带,非甲基化引物仅在非甲基化DNA模板获得阳性条带。MCF-7乳腺癌细胞中PELP1基因启动子区呈非甲基化状态,MCF-10正常乳腺导管上皮细胞中PELP1基因启动子区呈甲基化状态,MCF-10细胞中PELP1蛋白表达水平为MCF-7细胞的1/16(P0.05)。采用5'-Aza-dC去除MCF-10细胞PELP1基因启动子区甲基化后,PELP1蛋白表达水平上升了9.7倍(P0.05)。结论所建立的PELP1基因启动子区MSP检测方法特异性良好,去甲基化可能是导致乳腺癌细胞中PELP1基因过表达的重要机制。     

白血病Reh、HL-60、K562细胞系RUNX 3 基因P2启动子甲基化状态与RUNX 3 基因表达

目的: 研究人白血病Reh、HL-60与K562细胞系RUNX 3 基因P2启动子甲基化状态及RUNX 3 基因的表达,分析P2启动子甲基化与基因表达之间的关系。方法: 运用甲基化特异性PCR(MSP)和RT-PCR检测Reh、HL-60与K562细胞系RUNX 3 基因P2启动子的甲基化状态及RUNX 3 基因的表达。结果: Reh及K562细胞系RUNX 3 基因P2启动子甲基化特异性扩增呈阳性,非甲基化特异性扩增呈阴性,RT-PCR扩增呈阴性;而HL-60细胞系相反,甲基化特异性扩增呈阴性,而非甲基化特异性扩增呈阳性,RT-PCR扩增阳性。结论: Reh及K562细胞中存在RUNX 3 基因P2启动子的甲基化,且在不同类型白血病细胞系中的甲基化状态不同。     

4株乳腺癌细胞中内皮素受体B基因的甲基化状态及对MCF-7细胞增殖的影响

目的 探讨内皮素受体B（EDNRB）基因在4株乳腺癌细胞中的表达、甲基化状态以及恢复EDNRB表达对MCF-7细胞增殖的影响。 方法 采用甲基化特异性PCR（MS-PCR）和亚硫酸盐测序法（BSP）分析4株乳腺癌细胞中EDNRB的甲基化状态;反转录聚合酶链反应（RT-PCR）检测EDNRB mRNA的表达水平;采用四甲基偶氮唑蓝（MTT）法和集落形成实验检测EDNRB表达恢复对MCF-7细胞增殖的影响。 结果 EDNRB在乳腺癌细胞MCF-7和ZR-75-1中表达缺失,并呈高甲基化状态;而在EDNRB表达最高的MDA-MB-231细胞中其启动子呈低甲基化,表明乳腺癌细胞中EDNRB基因启动子甲基化状态与其表达成负相关。5-氮杂胞苷（5-Aza-CR）能够反转EDNRB基因的表达,EDNRB表达恢复后MCF-7细胞的增殖受到抑制。 结论 EDNRB基因启动子区CpG岛频繁甲基化可能在乳腺癌发生发展中发挥重要作用,EDNRB有望成为乳腺癌早期诊断的新的分子标志物。     

NDRG-1基因甲基化与乳腺癌发生的关系

目的 对NDRG-1基因启动子区甲基化状态进行研究,探讨NDRG-1基因甲基化在乳腺癌发生中的作用.方法 采用双色荧光杂交微阵列基因芯片技术对33例乳腺癌样本和癌旁组织样本进行NDRG-1基因启动子区甲基化状态研究.结果 33例肿瘤样本和癌旁组织样本中NDRG-1基因启动子区CpG位点均有不同程度的甲基化,肿瘤组织中NDRG-1基因启动子区CpG位点甲基化率显著高于相应的癌旁样本组织(t=14.12,P＜0.05).结论 DNA甲基化作为NDRG-1基因的重要调控机制,NDRG-1基因启动子区过甲基化可能在乳腺癌的发生过程中起重要作用.     

Multiple forms of BRMS1 are differentially expressed in the MCF10 isogenic breast cancer progression model

Clinical studies evaluating the mRNA expression level of the BRMS1 metastasis suppressor in the progression of breast cancer have not been consistent. The purpose of this study was to characterize endogenous BRMS1 mRNA and protein in a model of the progression of breast cancer. BRMS1 protein expression was evaluated in the genetically related MCF10 cell lines representing ‘normal’ breast epithelial cells (MCF10A), pre-malignant breast disease (MCF10AT), comedo ductal carcinoma in situ (MCF10DCIS.com), and metastatic carcinoma (MCF10CAa.1 and MCF10CAd.1α) with two antibodies that recognize distinct epitopes in the BRMS1 protein. Nuclear expression of the characteristic ~35 kDa BRMS1 protein was detected in all cell lines. Because BRMS1 was expressed in the metastatic MCF10 variants, the BRMS1 exons were sequenced to scan for possible genetic mutations. BRMS1 was wild-type with the exception of a synonymous T/C transition in exon 7. However, alternatively spliced variants were detected by RT-PCR. Two variants, BRMS1.v2 and BRMS1.v4 were only detected in the MCF10A and AT cell lines, while BRMS1 and BRMS1.v3 were detected in all lines. These results demonstrate that expression of the characteristic ~35 kDa BRMS1 protein is not sufficient to prevent metastasis. The differential expression of alternative splice variants suggests caution should be taken when evaluating BRMS1 mRNA in clinical samples.     

乳腺癌和乳腺导管内增生性病变Notch1基因甲基化的检测及临床意义

目的 探讨Notch1基因甲基化与乳腺浸润性导管癌(IDC)及乳腺导管内增生性病变的相关性.方法 用基质辅助激光解析电离时间飞行质谱仪(MALDI-TOF MS)对89例乳腺IDC、20例导管原位癌(DCLS)、11例不典型导管增生(ADH)及20例普通型导管增生(UDH)组织进行Notch1基因甲基化的定量检测.采用...     

细胞角蛋白在乳腺导管内增生性病变鉴别诊断中的应用

目的 研究细胞角蛋白(CK)在乳腺导管内增生性病变的表达情况,寻求帮助乳腺导管内增生性病变鉴别诊断的分子标记。方法 按Page标准选病例,收集本院1993～2002年病理标本,乳腺导管内增生性病变92例(石蜡包埋标本)、冷冻切片30例以及导管上皮普通性增生原代培养上皮细胞和浸润性导管癌细胞株T-47D和MCF-7。采用EnVision标准二步法研究CK34βE12、CK8以及CK14表达情况。结果 (1)石蜡组织中CK34βE12在导管上皮普通性增生、不典型性增生、导管原位癌以及浸润性导管癌的阳性结果分别为95．2％、33．3％、19．2％和12．5％;导管上皮普通性增生、浸润性导管癌的冷冻切片CK34βE12阳性率为100％和55％;CK34βE12在MCF7呈阴性染色,在普通性增生原代培养细胞及T-47D中呈阳性染色;(2)CK8与CK14在乳腺导管上皮普通性增生的表达模式与其他病变不同。结论 CK34βE12有助于乳腺导管内增生性病变的鉴别诊断,但还不适用于术中冷冻快速诊断;CK8与CK14在乳腺导管内增生性病变中的表达模式可有助于鉴别诊断。     

Mucinous breast carcinomas lack PIK3CA and AKT1 mutations

Activating point mutations in the phosphatidylinositol-3-kinase catalytic subunit (PIK3CA) are among the most common molecular defects in invasive breast cancer. Point mutations in the downstream kinase AKT1 are seen in a minority of carcinomas. These mutations are found preferentially in estrogen receptor-positive and Her2-positive breast carcinomas; however, special morphologic types of breast cancer have not been well studied. Twenty-nine cases of pure invasive mucinous carcinoma and 9 cases of ductal carcinoma with mucinous differentiation were screened for a panel of point mutations (>321 mutations in 30 genes) using a multiplex polymerase chain reaction panel with mass spectroscopy readout. In addition, associated ductal carcinoma in situ, hyperplasia, or columnar cell lesions were separately tested where available (25 lesions). In 3 invasive cases and 15 ductal carcinoma in situ/proliferative lesions, PIK3CA hotspot mutations were, instead, tested by direct sequencing. No point mutations were identified in invasive mucinous breast carcinoma. This contrasts with the 35% frequency of PIK3CA mutations in a comparative group of invasive ductal carcinomas of no special type. Interestingly, PIK3CA hotspot point mutations were identified in associated ductal carcinoma in situ (3/14) and hyperplasia (atypical ductal hyperplasia [2/3], usual ductal hyperplasia [2/3], columnar cell change [1/5]), suggesting that PIK3CA mutations may play a role in breast epithelial proliferation. This series represents the largest study, to date, of PIK3CA genotyping in mucinous carcinoma and supports the unique pathogenetics of invasive mucinous breast carcinoma.     

Reduced expression of oestrogen receptor beta in invasive breast cancer and its re-expression using DNA methyl transferase inhibitors in a cell line model

To gain insights into the possible role of oestrogen receptor (ER) beta in breast carcinogenesis, immunohistochemical analysis of ER beta was performed on 512 breast specimens encompassing normal (n = 138), pure ductal carcinoma in situ (n = 16), invasive cancers (n = 319), lymph node metastases (n = 31), and recurrences (n = 8). Real-time polymerase chain reaction (PCR) was used to investigate the methylation status of the ER beta gene in the ER beta negative breast cancer cell lines SkBr3 and MDA-MB-435. A gradual reduction in, but not a complete loss of, ER beta expression was observed during the transition from normal and pre-invasive lesions to invasive cancers, where ER beta was lost in 21% of cases. This was more pronounced in invasive ductal than in lobular carcinomas, a significantly higher proportion of which were ER beta-positive (74% compared with 91%, respectively, p = 0.0004). Examination of paired primary cancers with their axillary lymph node metastases showed that if ER beta was present in the primary tumour, it persisted in the metastasis. Treatment of ER beta-negative cell lines with DNA methyl transferase inhibitors restored ER beta expression, providing experimental evidence that silencing of ER beta in breast carcinomas could be due to promoter hypermethylation. These results suggest that loss of ER beta expression is one of the hallmarks of breast carcinogenesis and that it may be a reversible process involving methylation.     

Matrix detachment and proteasomal inhibitors diminish Sulf-2 expression in breast cancer cell lines and mouse xenografts

Sulfatase 2 (Sulf-2) has been previously shown to be upregulated in breast cancer. Sulf-2 removes sulfate moieties on heparan sulfate proteoglycans which in turn modulate heparin binding growth factor signaling. Here we report that matrix detachment resulted in decreased Sulf-2 expression in breast cancer cells and increased cleavage of poly ADP-ribose polymerase. Silencing of Sulf-2 promotes matrix detachment induced cell death in MCF10DCIS cells. In an attempt to identify Sulf-2 specific inhibitor, we found that proteasomal inhibitors such as MG132, Lactacystin and Bortezomib treatment abolished Sulf-2 expression in multiple breast cancer cell lines. Additionally, we show that Bortezomib treatment of MCF10DCIS cell xenografts in mouse mammary fat pads significantly reduced tumor size, caused massive apoptosis and more importantly reduced Sulf-2 levels in vivo. Finally, our immunohistochemistry analysis of Sulf-2 expression in cohort of patient derived breast tumors indicates that Sulf-2 is significantly upregulated in autologous metastatic lesions compared to primary tumors (p < 0.037, Pearson correlation, Chi-Square analysis). In all, our data suggest that Sulf-2 might play an important role in breast cancer progression from ductal carcinoma in situ into an invasive ductal carcinoma potentially by resisting cell death.     

Human breast fibroblasts inhibit growth of the MCF10AT xenograft model of proliferative breast disease

Stromal fibroblasts are important for normal breast homeostasis and regulation of epithelial growth; however, this regulatory function is altered during carcinogenesis. To study the role of fibroblasts in the development of breast cancer, fibroblasts derived from normal breast (NAFs) were incorporated into the MCF10AT xenograft model of progressive proliferative breast disease. The persistence of human NAFs in xenografts was established by intracellular labeling and tyramide-coupled fluorescent in situ hybridization. Overall, the number of MCF10AT epithelial structures was decreased, and the rate of epithelial cell apoptosis was increased in xenografts containing NAFs. However, these changes were primarily in low-grade epithelial structures, corresponding to normal or mildly hyperplastic ductal epithelium. The level and rate of apoptosis of high-grade epithelial structures, corresponding to in situ and invasive carcinoma, were not consistently altered by NAFs. In addition, there was variability in the growth-inhibitory capacity of NAFs derived from different individuals. NAFs induced changes in the morphology of high-grade MCF10AT structures and in xenograft stroma, including the composition of extracellular matrix, and increased angiogenesis and lymphocytic infiltration. These findings imply that NAFs can inhibit the growth of normal and hyperplastic epi-thelium but are less able to regulate the more transformed epithelial cells that arise during carcino-genesis.