乳腺癌细胞中ERα和DNA甲基化调控CLDN6表达的作用及其机制
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摘要
目的:探讨乳腺癌细胞MCF-7中雌激素受体α(estrogen receptor alpha, ERα)和DNA甲基化介导CLDN6表达的作用机制及其对MCF-7细胞转移表型的影响。
方法:采用RT-PCR、Western blot及细胞免疫荧光法检测ERα激动剂(propyl pyrazole triol,PPT)和雌激素受体(estrogen receptor, ER)阻断剂ICI 182,780(ICI)对CLDN6表达的影响;采用Western blot和甲基化特异性PCR(methylation specific PCR,MSP)法检测乳腺癌组织中CLDN6表达和DNA甲基化状态并分析其相互关系;利用5-aza-dC和TSA作用MCF-7细胞,采用RT-PCR、Western blot、细胞免疫荧光法及MSP法检测乳腺癌细胞中CLDN6表达和DNA甲基化状态,用染色质免疫沉淀技术(Chromatin immunoprecitation,ChIP)检测CLDN6基因与甲基化CpG位点结合蛋白2(5 methyl-CpG binding protein 2,MeCP2)、乙酰化的组蛋白(acetylated H3,H3Ac;acetylated H4,H4Ac)结合;用核酸酶可及性实验分析CLDN6基因所在区域染色质构象;用RNAi技术分析沉默MeCP2对CLDN6表达的影响;划痕法和Transwell小室分析DNA甲基化下调CLDN6表达对MCF-7迁移和侵袭表型的影响。
结果:PPT能够上调MCF-7细胞CLDN6的表达,ICI能够阻断PPT对CLDN6表达的诱导作用;乳腺癌组织和细胞中CLDN6低表达,并与DNA甲基化有关;5-aza-dC和TSA单独及联合作用MCF-7细胞能够上调CLDN6表达;5-aza-dC作用MCF-7细胞可以抑制MeCP2与CLDN6基因的结合,促进H3Ac和H4Ac与CLDN6基因的结合,TSA可以促进H4Ac与CLDN6基因的结合;5-aza-dC可以使MCF-7细胞中CLDN6基因CpG岛附近染色质结构变疏松;RNAi技术沉默MeCP2对CLDN6表达无明显影响;5-aza-dC可抑制MCF-7细胞的侵袭和迁移能力,沉默5-aza-dC作用组细胞中的CLDN6基因能够增强细胞的迁移和侵袭能力。
结论:ERα可以上调MCF-7细胞中CLDN6表达;乳腺癌组织和细胞中CLDN6表达下调与DNA甲基化有关;DNA甲基化下调CLDN6表达与MeCP2的结合、组蛋白H3和H4脱乙酰化及染色质构象改变有关;DNA甲基化下调CLDN6表达可以促进MCF-7细胞的转移表型。
Tight junctions (TJ) are located at the extreme apical region of junction-associated complexes in epithelial and endothelial cells, where they play important roles in maintaining cell polarity, cell adherence and regulating cell proliferation and differentiation. Claudins (CLDNs) are the main components of tight junctions, forming the backbone of tight junction strands and transmitting cellular signals. Their expression has been reported altered in several cancers. For example, CLDN1 was downregulated in breast cancer and colon cancer, CLDN7 was reduced in invasive breast cancer , CLDN3 and CLDN4 have been reported to be upregulated in ovarian cancer. Whether upregulated or downregulated, the functions and structure of tight junctions are often abnormal in a number of cancers .
CLDN6, one of 24 members of the CLDN family, it is located on chromosome 16 p13.3,encodes a 23 kDa membrane protein of 219 amino acids. Recent reports show that CLDN6 can regulate adipogenesis and fat deposition , it is required for normal blastocyst formation, it is important for maintaining permeability barriers and transepithelial resistance of epidermal cells. In previous work, we found that the expression of CLDN6 was down-regulated in human and rat mammary cancer cell lines. MCF-7 cells transfected with CLDN6 grew slowly, anchorage-independent growth, invasive and migratory traits were also substantially decreased in cells with CLDN6 expression. These results suggest that CLDN6 may act as a cancer suppressor.
According to our previous work, CLDN6 expression was related to ERαin breast cancer tissues and 17β-estradiol(17β-E2)could up-regulate the expression of CLDN6 in MCF-7 cells. According to current reports, ERαmight regulate the expression of CLDN1, 3, 4 in breast cancer tissues. But, the roles of ERαin the regulation of expression of CLDN6 in MCF-7 cells is unclear.
According to current reports, DNA methylation could down-regulate CLDNs expression. DNA methylation leads to transcriptional repression either by directly interfering with the binding of transcription factors or by the involvement of proteins that specifically recognize methylated CpGs, the prototype of which is the methyl-CpG-binding protein 2 (MeCP2); MeCP2 specifically targets mCpGs and determines repressive heterochromatin by interacting with histone deacetylases and histone methyltransferase; DNA methylation could also repress gene transcription by mechanisms of chromatin condensation. There are some reports that DNA methylation could down-regulate CLDN6 expression in breast cancer cells and esophageal carcinoma tissues. However, the mechanisms of 17-β-estradiol and DNA methylation regulating the expression of CLDN6 are still unclear.
This study sought to determine the role of ERs in the regulation of expression of CLDN6 and the mechanism of DNA methylation regulating the expression of CLDN6.
Methods:
1. The effects of ERαon CLDN6 expression: PPT and ICI treatment were performed. The expression of CLDN6 was measured by reverse transcriptase-PCR (RT-PCR), western blotting and immunofluorescent staining.
2. Expression of CLDN6 and DNA methylation : RT-PCR, western blotting, immunofluorescent staining were used to determine the expression of CLDN6 in breast cancer tissues and control tissues and breast cancer cells without or with 5-Aza-2’-deoxycytidine (5-aza-dC) and Trichostatin A (TSA) treated; Methylation-Specific PCR (MSP) was used to determine methylation status at the CLDN6 gene.
3. The machanism DNA methylation regulating the expression of CLDN6: ChIP was used to determine the combination of CLDN6 with MeCP2, H3Ac and H4Ac protein; Nuclease accessibility assays was performed to obtain information about the nucleosomal organization of the CLDN6 gene. To confirm the role of MeCP2 in the regulation of CLDN6 expression in MCF-7 cells, we used RNAi to knockdown MeCP2 in MCF-7 cells.
4. The effects DNA methylation of CLDN6 gene on metastasis phaenotype of MCF-7: Wound healing assay and transwell assay were used to determine the metastasis phaenotype of MCF-7.
Results:
1. The effects of ERαon CLDN6 expression: PPT could upregulate the expression of CLDN6, and the effect could be blocked by ICI.
2. Expression of CLDN6 and DNA methylation:The expression of CLDN6 in breast cancer was lower than control group, lymphode metastasis group was lower than control group. DNA methylation of CLDN6 in breast cancer was higher than control group. MCF-7 cells did not express CLDN6 in accord with hypermethylation at the CLDN6 CpG sites, 5-aza-dC and TSA could induce the expression of CLDN6 separately or simultaneously. And 5-aza-dC could increase CLDN6 demethylation status.
3. The machanism DNA methylation regulating the expression of CLDN6: 5-aza-dC can inhibit the combination of CLDN6 with MeCP2, H3Ac and H4Ac; After treating MCF-7 with 5-aza–dC, the chromatin structure nearby CLDN6 gene became more loose than control group; MeCP2 silence have no effection on the expression of CLDN6.
4. The effects of CLDN6 gene DNA methylation on metastasis phaenotype of MCF-7: 5-aza-dC could suppress migration and metastatic ability of MCF-7; Slience expression of CLDN6 in the 5-aza-dC treated group would enhance the migration and metastatic ability.
Conclusions:
1. ERαcould upregulate the expression of CLDN6.
2. CLDN6 expression was related to DNA methylation in breast cancer tissues and cells.
3. DNA methylation down-regulated CLDN6 expression releated to the combination of CLDN6 with MeCP2, H3, H4 deacetylation and the chromatin structure alteration.
4. DNA methylation down-regulated CLDN6 expression would enhance migration phenotype of MCF-7 cells.
方法:采用RT-PCR、Western blot及细胞免疫荧光法检测ERα激动剂(propyl pyrazole triol,PPT)和雌激素受体(estrogen receptor, ER)阻断剂ICI 182,780(ICI)对CLDN6表达的影响;采用Western blot和甲基化特异性PCR(methylation specific PCR,MSP)法检测乳腺癌组织中CLDN6表达和DNA甲基化状态并分析其相互关系;利用5-aza-dC和TSA作用MCF-7细胞,采用RT-PCR、Western blot、细胞免疫荧光法及MSP法检测乳腺癌细胞中CLDN6表达和DNA甲基化状态,用染色质免疫沉淀技术(Chromatin immunoprecitation,ChIP)检测CLDN6基因与甲基化CpG位点结合蛋白2(5 methyl-CpG binding protein 2,MeCP2)、乙酰化的组蛋白(acetylated H3,H3Ac;acetylated H4,H4Ac)结合;用核酸酶可及性实验分析CLDN6基因所在区域染色质构象;用RNAi技术分析沉默MeCP2对CLDN6表达的影响;划痕法和Transwell小室分析DNA甲基化下调CLDN6表达对MCF-7迁移和侵袭表型的影响。
结果:PPT能够上调MCF-7细胞CLDN6的表达,ICI能够阻断PPT对CLDN6表达的诱导作用;乳腺癌组织和细胞中CLDN6低表达,并与DNA甲基化有关;5-aza-dC和TSA单独及联合作用MCF-7细胞能够上调CLDN6表达;5-aza-dC作用MCF-7细胞可以抑制MeCP2与CLDN6基因的结合,促进H3Ac和H4Ac与CLDN6基因的结合,TSA可以促进H4Ac与CLDN6基因的结合;5-aza-dC可以使MCF-7细胞中CLDN6基因CpG岛附近染色质结构变疏松;RNAi技术沉默MeCP2对CLDN6表达无明显影响;5-aza-dC可抑制MCF-7细胞的侵袭和迁移能力,沉默5-aza-dC作用组细胞中的CLDN6基因能够增强细胞的迁移和侵袭能力。
结论:ERα可以上调MCF-7细胞中CLDN6表达;乳腺癌组织和细胞中CLDN6表达下调与DNA甲基化有关;DNA甲基化下调CLDN6表达与MeCP2的结合、组蛋白H3和H4脱乙酰化及染色质构象改变有关;DNA甲基化下调CLDN6表达可以促进MCF-7细胞的转移表型。
Tight junctions (TJ) are located at the extreme apical region of junction-associated complexes in epithelial and endothelial cells, where they play important roles in maintaining cell polarity, cell adherence and regulating cell proliferation and differentiation. Claudins (CLDNs) are the main components of tight junctions, forming the backbone of tight junction strands and transmitting cellular signals. Their expression has been reported altered in several cancers. For example, CLDN1 was downregulated in breast cancer and colon cancer, CLDN7 was reduced in invasive breast cancer , CLDN3 and CLDN4 have been reported to be upregulated in ovarian cancer. Whether upregulated or downregulated, the functions and structure of tight junctions are often abnormal in a number of cancers .
CLDN6, one of 24 members of the CLDN family, it is located on chromosome 16 p13.3,encodes a 23 kDa membrane protein of 219 amino acids. Recent reports show that CLDN6 can regulate adipogenesis and fat deposition , it is required for normal blastocyst formation, it is important for maintaining permeability barriers and transepithelial resistance of epidermal cells. In previous work, we found that the expression of CLDN6 was down-regulated in human and rat mammary cancer cell lines. MCF-7 cells transfected with CLDN6 grew slowly, anchorage-independent growth, invasive and migratory traits were also substantially decreased in cells with CLDN6 expression. These results suggest that CLDN6 may act as a cancer suppressor.
According to our previous work, CLDN6 expression was related to ERαin breast cancer tissues and 17β-estradiol(17β-E2)could up-regulate the expression of CLDN6 in MCF-7 cells. According to current reports, ERαmight regulate the expression of CLDN1, 3, 4 in breast cancer tissues. But, the roles of ERαin the regulation of expression of CLDN6 in MCF-7 cells is unclear.
According to current reports, DNA methylation could down-regulate CLDNs expression. DNA methylation leads to transcriptional repression either by directly interfering with the binding of transcription factors or by the involvement of proteins that specifically recognize methylated CpGs, the prototype of which is the methyl-CpG-binding protein 2 (MeCP2); MeCP2 specifically targets mCpGs and determines repressive heterochromatin by interacting with histone deacetylases and histone methyltransferase; DNA methylation could also repress gene transcription by mechanisms of chromatin condensation. There are some reports that DNA methylation could down-regulate CLDN6 expression in breast cancer cells and esophageal carcinoma tissues. However, the mechanisms of 17-β-estradiol and DNA methylation regulating the expression of CLDN6 are still unclear.
This study sought to determine the role of ERs in the regulation of expression of CLDN6 and the mechanism of DNA methylation regulating the expression of CLDN6.
Methods:
1. The effects of ERαon CLDN6 expression: PPT and ICI treatment were performed. The expression of CLDN6 was measured by reverse transcriptase-PCR (RT-PCR), western blotting and immunofluorescent staining.
2. Expression of CLDN6 and DNA methylation : RT-PCR, western blotting, immunofluorescent staining were used to determine the expression of CLDN6 in breast cancer tissues and control tissues and breast cancer cells without or with 5-Aza-2’-deoxycytidine (5-aza-dC) and Trichostatin A (TSA) treated; Methylation-Specific PCR (MSP) was used to determine methylation status at the CLDN6 gene.
3. The machanism DNA methylation regulating the expression of CLDN6: ChIP was used to determine the combination of CLDN6 with MeCP2, H3Ac and H4Ac protein; Nuclease accessibility assays was performed to obtain information about the nucleosomal organization of the CLDN6 gene. To confirm the role of MeCP2 in the regulation of CLDN6 expression in MCF-7 cells, we used RNAi to knockdown MeCP2 in MCF-7 cells.
4. The effects DNA methylation of CLDN6 gene on metastasis phaenotype of MCF-7: Wound healing assay and transwell assay were used to determine the metastasis phaenotype of MCF-7.
Results:
1. The effects of ERαon CLDN6 expression: PPT could upregulate the expression of CLDN6, and the effect could be blocked by ICI.
2. Expression of CLDN6 and DNA methylation:The expression of CLDN6 in breast cancer was lower than control group, lymphode metastasis group was lower than control group. DNA methylation of CLDN6 in breast cancer was higher than control group. MCF-7 cells did not express CLDN6 in accord with hypermethylation at the CLDN6 CpG sites, 5-aza-dC and TSA could induce the expression of CLDN6 separately or simultaneously. And 5-aza-dC could increase CLDN6 demethylation status.
3. The machanism DNA methylation regulating the expression of CLDN6: 5-aza-dC can inhibit the combination of CLDN6 with MeCP2, H3Ac and H4Ac; After treating MCF-7 with 5-aza–dC, the chromatin structure nearby CLDN6 gene became more loose than control group; MeCP2 silence have no effection on the expression of CLDN6.
4. The effects of CLDN6 gene DNA methylation on metastasis phaenotype of MCF-7: 5-aza-dC could suppress migration and metastatic ability of MCF-7; Slience expression of CLDN6 in the 5-aza-dC treated group would enhance the migration and metastatic ability.
Conclusions:
1. ERαcould upregulate the expression of CLDN6.
2. CLDN6 expression was related to DNA methylation in breast cancer tissues and cells.
3. DNA methylation down-regulated CLDN6 expression releated to the combination of CLDN6 with MeCP2, H3, H4 deacetylation and the chromatin structure alteration.
4. DNA methylation down-regulated CLDN6 expression would enhance migration phenotype of MCF-7 cells.
引文
[1] Van Itallie C M, Anderson J M. Occludin confers adhesiveness when expressed in fibroblasts [J]. J Cell Sci,1997,110: 1113-1121.
[2] Furuse M, Fujita K, Hiiragi T, et al. CLDN1 and -2: novel integral membrane proteins localizing at tight junctions with no sequence similarity to occluding [J]. J Cell Biol, 1998,141:1539-1550.
[3] Tsukita S, Sasaki H, Fujimoto K, et.al. A single gene product, claudin 1 or 2, reconstitutes tight junction strands and recruits occludin in fibroblasts [J]. Cell Biol, 1998,143: 391–401.
[4] Turksen K, Troy TC. Barriers built on claudins [J]. Cell Biol, 2004, 117: 2435-2447.
[5] Morita K, Furuse M, Fujimoto K, et.al. Claudin multigene family encoding four-transmembrane domain protein components of tight junction strands [J]. Proc. Natl. Acad. Sci. USA, 1999, 96:511–516.
[6] Oscar RC, Christina VI, Christoph R, et.al. Claudin extracellular domains determine paracellular charge selectivity and resistance but not tight junction fibril architecture [J]. Physiol Cell Physiol, 2003, 284(6): 1346-1354.
[7] Fujita K., Katahira J., Horiguchi Y., et al. Clostridium perfringens enterotoxin binds to the second extracellular loop of CLDN3, a tight junction integral membrane protein [J]. FEBS Lett, 2000,476:258-261.
[8] Van Itallie C M, Colegio O R., Anderson J M. The cytoplasmic tails of claudins can influence tight junction barrier properties through effects on protein stability [J]. J Membr Biol, 2004,199:29-38.
[9] Tsukita S, Furuse M, Itoh M. Multifunctional strands in tight junctions [J]. Nat Rev Mol Cell Biol, 2001, 2:285–293.
[10] Coyne C B, Gambling T M, Boucher R C, et al. Role of claudin interactions in airway tight junctional permeability [J]. Am J Physiol Lung Cell Mol Physiol, 2003,285:1166-1178.
[11] Kubota K, Furuse M, Sasaki H, et al. Ca2+-independent cell-adhesion activity of claudins, a family of integral membrane proteins localized at tight junctions [J]. Curr Biol, 1999,9(18): 1035-1038.
[12] Amasheh S, Schmidt T, Mahn M, et al. Contribution of CLDN5 to barrier properties in tight junctions of epithelial cells [J]. Cell Tissue Res, 2005, 321:89-96.
[13] Abuazza G, Becker A, Williams S S, et al. Claudins 6, 9, and 13 are developmentally expressed renal tight junction proteins [J]. Am J Physiol Renal Physiol, 2006,291:F1132-1141.
[14] Morita K, Furuse M, Fujimoto K, et.al. Claudin multigene family encoding four-transmembrane domain protein components of tight junction strands [J]. Proc. Natl. Acad. Sci. USA, 1999, 96:511–516.
[15] Aung PP, Mitani Y, Sanada Y, et.al. Differential expression of claudin-2 in normal human tissues and gastrointestinal carcinomas [J]. Virchows Arch, 2006,448(4):428-434.
[16] Morita K, Sasaki H, Furuse M, et al. Endothelial claudin: claudin- 5/TMVCF constitutes tight junction strands in endothelial cells[J]. J Cell Biol. 1999; 147(1): 185–194.
[17] Holmes J L, Itallie C, Rasmussen J E, et al. Claudin profiling in the mouse during postnatal intestinal development and along the gastrointestinal tract reveals complex expression patterns [J]. Gene Expr Patterns, 2006,6(6): 581–588.
[18] Rahner C, Mitic L L, Anderson J M. Heterogeneity in expression and subcellular localization of claudins 2, 3, 4, and 5 in the rat liver, pancreas, and gut [J] . Gastroenterology, 2001; 120(2): 411–422.
[19] Kiuchi-Saishin Y, Gotoh S, Furuse M, et al. Differential expression patterns of claudins, tight junction membrane proteins, in mouse nephron segments [J]. J Am Soc Nephrol. 2002; 13 (4): 875–886.
[20] Morohashi S, Kusumi T, Sato F, et al. Decreased expression of CLDN1 correlates with recurrence status in breast cancer [J]. Int J Mol Med, 2007, 20: 139-143.
[21] Miyamoto K, Kusumi T, Sato F, et al. Decreased expression of CLDN1 is correlated with recurrence status in esophageal squamous cell carcinoma [J]. Biomed Res, 2008, 29: 71-76.
[22] Miwa N, Furuse M, Tsukita S, et al. Involvement of CLDN1 in the beta-catenin/Tcf signaling pathway and its frequent upregulation in human colorectal cancers[J]. Oncol Res, 2001,12: 469-476.
[23] Dhawan P, Singh A B, Deane N G, et al. CLDN1 regulates cellular transformation and metastatic behavior in colon cancer [J]. J Clin Invest, 2005,115:1765-1776.
[24] Paschoud S, Bongiovanni M, Pache J C, et al. CLDN1 and CLDN5 expression patterns differentiate lung squamous cell carcinomas from adenocarcinomas [J]. Mod Pathol, 2007, 20: 947-954.
[25] Oku N, Sasabe E, Ueta E, et al. Tight junction protein CLDN1 enhances theinvasive activity of oral squamous cell carcinoma cells by promoting cleavage of laminin-5 gamma2 chain via matrix metalloproteinase (MMP)-2 and membrane-type MMP-1 [J]. Cancer Res,2006, 66: 5251-5257.
[26] Cohn M L, Goncharuk V N, Diwan A H, et al. Loss of CLDN1 expression in tumor-associated vessels correlates with acquisition of metastatic phenotype in melanocytic neoplasms [J]. J Cutan Pathol, 2005,32: 533-536.
[27] Aung P P, Mitani Y, Sanada Y, et al. Differential expression of CLDN2 in normal human tissues and gastrointestinal carcinomas [J]. Virchows Arch, 2006, 448: 428-434.
[28] Soini Y, Tommola S, Helin H, et al. Claudins 1, 3, 4 and 5 in gastric carcinoma, loss of claudin expression associates with the diffuse subtype [J]. Virchows Arch, 2006, 448: 52-58.
[29] Nacht M, Ferguson A T, Zhang W, et al. Combining serial analysis of gene expression and array technologies to identify genes differentially expressed in breast cancer [J]. Cancer Res, 1999,59:5464-5470.
[30] Hough C D, Sherman-Baust C A, Pizer E S, et al. Large-scale serial analysis of gene expression reveals genes differentially expressed in ovarian cancer [J]. Cancer Res, 2000,60: 6281-6287.
[31] Hewitt K J, Agarwal R, Morin P J. The claudin gene family: expression in normal and neoplastic tissues [J]. BMC Cancer, 2006,6:186.
[32] Takala H, Saarnio J, Wiik H, et al. Claudins 1, 3, 4, 5 and 7 in esophageal cancer: loss of claudin 3 and 4 expression is associated with metastatic behavior [J]. APMIS, 2007, 115: 838-847.
[33] Michl P, Barth C, Buchholz M, et al. CLDN4 expression decreases invasiveness and metastatic potential of pancreatic cancer [J]. Cancer Res, 2003,63: 6265-6271.
[34] Nichols LS, Ashfaq R, Iacobuzio-Donahue CA. Claudin 4 protein expression in primary and metastatic pancreatic cancer: support for use as a therapeutic target [J]. Am J Clin Pathol, 2004,121: 226-230.
[35] Vare P, Loikkanen I, Hirvikoski P, et al. Low claudin expression is associated with high Gleason grade in prostate adenocarcinoma [J]. Oncol Rep, 2008, 19: 25-31.
[36] Makoto O, Masaki M, Hideki C, et al. Epigenetic silencing of claudin-6 promotes anchorage-independent growth of breast carcinoma cells [J].Can Sci. 2007,98: 1557-62.
[37] Tsunoda S, Smith E. Methylation of CLDN6, FBN2, RBP1, RBP4, TFPI2, and TMEFF2 in esophageal squamous cell carcinoma [J]. Oncol Rep. 2009,21:1067-1073.
[38] Borlak J, Meier T, Halter R, et al. Epidermal growth factor-induced hepatocellular carcinoma: gene expression profiles in precursor lesions, early stage and solitary tumours [J]. Oncogene, 2005,24: 1809-1819.
[39] Tzelepi VN, Tsamandas AC, Vlotinou HD, et al. Tight junctions in thyroid carcinogenesis: diverse expression of CLDN1, CLDN4, CLDN7 and occludin in thyroid neoplasms [J]. Mod Pathol, 2008,21: 22-30.
[40] Adam H J, Henry F F, Alexander Z, et.al. Expression of Tight-Junction Protein Claudin-7 Is an Early Event in Gastric Tumorigenesis [J]. American Journal of Pathology, 2005, 167:577-584.
[41] Cheung ST, Leung KL, Ip YC, et al. CLDN10 expression level is associated with recurrence of primary hepatocellular carcinoma [J]. Clin Cancer Res, 2005, 11: 551-556.
[42] Nemeth Z, Szasz AM, Tatrai P, et al. CLDN1, -2, -3, -4, -7, -8, and -10 protein expression in biliary tract cancers [J]. J Histochem Cytochem, 2009, 57: 113-121.
[43] Kohno Y, Okamoto T, Ishibe T, et al. Expression of claudin7 is tightly associated with epithelial structures in synovial sarcomas and regulated by an Etsfamily transcription factor, ELF3 [J]. J Biol Chem, 2006, 281: 38941-38950.
[44] Rangel LB., Sherman-Baust CA, Wernyj RP, et al. Characterization of novelhuman ovarian cancer-specific transcripts (HOSTs) identified by serial analysis of gene expression [J]. Oncogene, 2003, 22:7225-7232.
[45] Yoshiki K, Takeshi O, Tatsuya I. Expression of Claudin 7 Is Tightly Associated with Epithelial Structures in Synovial Sarcomas and Regulated by an Ets Family Transcription Factor, ELF3 [J]. Biol. Chem, 2006, 281(50): 38941-38950.
[46] Ikenouchi J, Matsuda M, Furuse M, et al. Regulation of tight junctions during the epithelium–mesenchyme transition: direct repression of the gene expression of claudins/occludin by Snail [J]. Cell Sci, 2003,116: 1959–1967.
[47] D'Souza T, Agarwal R, Morin P J.Phosphorylation of claudin-3 at threonine 192 by cAMP-dependent protein kinase regulates tight junction barrier function in ovarian cancer cells [J]. Biol. Chem, 2005,280: 26233–26240.
[48] Ikari A, Matsumoto S, Harada H, et al. Phosphorylation of paracellin-1 at Ser217 by protein kinase A is essential for localization in tight junctions [J]. Cell Sci, 2006, 119: 1781–1789.
[49] Thompson GE. Cortisol and regulation of tight junctions in the mammary gland of the late-pregnant goa.t [J]. Dairy Res, 1996,63:305–308.
[50] Forster C, Makela S, Warri A, et al. Involvement of estrogen receptor ? in terminal differentiation of mammary gland epithelium [J]. Proc Natl Acad Sci USA, 2002, 99:15578–15583.
[51] Liu Yafang, Wu Qiong, Ren Yue, et al. Role of estrogen receptor-αin regulating claudin-6 expression in breast cancer cells [J]. J Breast Cancer 2011,14(1):20-27.
[52] Liu YF, Wu Q, Xu XM, et al. Effects of 17beta-estradiol on proliferation and migration of MCF-7 cell by regulating expression of claudin-6. Zhong hua Bing Li Xue Za Zhi [J]. 2010,39:44-47.
[53] Nakayama F, Semba S, Usami Y, et al. Hypermethylation-modulated downregulation of claudin-7 expression promotes the progression of colorectal carcinoma. Pathobiology [J]. 2008,75(3):177-85.
[54] Losel R, Wehling M, Jensen EV, et al. Estrogen receptors and proliferation markers in primary and recurrent breust caacett [J]. Proc Neff Aced Sci USA, 2001, 98(26): 15197-15202.
[55] Nilsson S, Makela S, Treuter E, et al. Mechanisms of estrogen action [J]. Physiol Rev Gustafsson, 2001,81:1535–1565.
[56] Gottlicher M, Heck S, Herrlich P. Transcriptional,cross-talk, the second mode of steroid hormone receptor action [J]. Mol Med, 1998, 76:480–489.
[57] Ito M, Weiss J. Estrogen receptor binding to DNA is not required for its activtiy through the nonclassical AP1 pathway [J]. Biol Chem, 2001, 276(17):13615-13621.
[58] Levin ER. Cellular functions of plasma membrane estrogen receptors [J]. Steroids, 2002, 67: 471-475.
[59] Blanchard AA, Skliris GP, Watson PH, et al. CLDNs 1, 3, and 4 protein expression in ER negative breast cancer correlates with markers of the basal phenotype. Virchows Arch 2009, 454: 647–656.
[60] Lin Y, Tracey AM, Christian P, et al. Biphasic effects of 17-β-estradiol on expression of occludin and transendothelial resistance and paracellular permeability in human vascular endothelial cells.[J]. Cell. Physiol, 2003, 196: 362-369.
[61] Shikhar Sharma, Theresa K. Epigenetics in cancer [J]. Carcinogenesis, 2010,1 : 27~36.
[62] Jones PA,Baylin SB. The fundamental role of epigenetic events in cancer [J]. Nat Rev Genet, 2002,3: 415-428.
[63] Klose RJ, Bird AP. Genomic DNA methylation:the mark and its mediators [J].Trends Biochem Sci. 2006;31:89-97.
[64] Glass JL, Thompson RF, Khulan B, et al.CG dinucleotide clustering is a speciesspecific property of the genome [J]. Nucleic Acids Res, 2007,35:6798-6807.
[65] Illingworth RS, Bird AP. CpG islands–‘a rough guide.’FEBS Lett. 2009;583:1713-1720.
[66] Adrian Bird. Perceptions of epigenetics [J].Nature, 2007, 447:396-398.
[67] Reik W, Dean W, Walter J. Epigenetic reprogramming in mammalian development [J]. Science, 2001,293:1089-1093.
[68] Morgan HD, Sutherland HG, Martin DI, et al. Epigenetic inheritance at the agouti locus in the mouse [J]. Nat Genet, 1999,23:314-318.
[69] Hu JL, Zhou BO,The N-terminus of histone H3 is required for de novo DNA methylation in chromatin [J]. Proc Natl Acad Sci USA, 200929,106(52):22187-92.
[70] Baylin, SB, Jones, P.A. Epigenetic determinants of cancer [J]. In Epigenetics, 2007:457-476.
[71] Ballestar E, and Esteller M. Epigenetic gene regulation in cancer [J]. Adv. Genet, 2008,61:247-267.
[72] Murayama A, Sakura K, Nakama M, et al. A specific CpG site demethylation in the human interleukin 2 gene promoter is an epigenetic memory [J]. EMBO J, 2006, 25:1081-1092.
[73] Ahmed H, Banerjee PP, Vasta GR. Differential expression of galectins in normal, benign and malignant prostate epithelial cells: Silencing of galectin-3 expression in prostate cancer by its promoter methylation [J]. Biochem Biophys Res, 2007, 358: 41-246.
[74] Kim JH, Hwang EH, Park HJ, et al. Methylation of CpG islands in the rat 7-dehydrocholesterol reductase promoter suppresses transcriptional activation [J]. Mol. Cells, 2005,19:279-282.
[75] Motegi K, Azuma M., Tamatani T, et al. Expression of aquaporin-5 in and fluid secretion from immortalized human salivary gland ductal cells by treatment with 5-aza-2′-deoxycytidine: a possibility for improvement of xerostomia in patients with Sjogren’s syndrome [J]. Lab. Invest, 2005, 85:342-353.
[76] Shikhar Sharma, Theresa K. Epigenetics in cancer [J]. Carcinogenesis, 2010,1:27-36.
[77] Singal R, Ginder G D. DNA methylation [J]. Blood, 1999, 93(12):4059-4070.
[78] McGough JM, Yang DF, Huang, S, et al. DNA methylation repressesIFN-gamma-induced and signal transducer and activator of transcription 1-mediated IFN regulatory factor 8 activation in colon carcinoma cells [J]. Mol. Cancer Res, 2008,6:1841-1851.
[79] Murayama A, Sakura K, Nakama M, et al. A specific CpG site demethylation in the human interleukin 2 gene promoter is an epigenetic memory [J]. EMBO J, 2006, 25:1081-1092.
[80] Clark SJ, Harrison J, Molloy PL. Sp1 binding is inhibited by (m)Cp(m)CpG methylation [J]. Gene, 1997,195: 67-71.
[81] Zhu WG, Srinivasan K, Dai ZY, et al. Methylation of adjacent CpG sites affects Sp1/Sp3 binding and activity in the p21(Cip1) promoter [J]. Mol. Cell. Biol, 2003,23: 4056-4065.
[82] Nan X, Ng HH, Johnson CA, et al. Transcriptional repression by the methyl-CpG-binding protein MeCP2 involves a histone deacetylase complex [J]. Nature, 1998,393:386-389.
[83] Cannistraro VJ, Taylor JS. Methyl CpG binding protein 2 (MeCP2) enhances photodimer formation at methyl-CpG sites but suppresses dimer deamination [J]. Nucleic Acids Res, 2010, 38(20):6943-6955.
[84] Dandrea M, Donadelli M, Costanzo C, et al. MeCP2/H3meK9 are involved in IL-6 gene silencing in pancreatic adenocarcinoma cell lines [J]. Nucleic Acids Research, 2009; 37(20):6681–90.
[85] Müller I, Wischnewski F, Pantel K, et al. Promoter- and cell-specific epigenetic regulation of CD44, Cyclin D2, GLIPR1 and PTEN by Methyl-CpG binding proteins and histone modifications [J]. BMC Cancer, 2010,17 (10) :297.
[86] Bowen NJ, Palmer MB, Wade PA. Chromosomal regulation by MeCP2: structural and enzymatic considerations [J]. Cell Mol. Life Sci, 2004,61: 2163-2167.
[87] Honda H, Pazin MJ, D'Souza T, et al. Regulation of the CLDN3 gene in ovarian cancer cells [J]. Cancer Biol Ther, 2007,6(11):1733-42.
[88] Stéphanie B, Michael B, Michael SS, et al. DNA-methylation-dependent alterations of claudin-4 expression in human bladder carcinoma [J]. Carcinogenesis, 2007 28(2):246-258.
[89] Litkouhi B. Claudin-4 overexpression in epithelial ovarian cancer is associated with hypomethylation and is a potential target for modulation of tight junction barrier function using a C-terminal fragment of Clostridium perfringens enterotoxin [J]. Neoplasia,2007,9:304-314.
[90] Honda H. Crucial roles of Sp1 and epigenetic modifications in the regulation of the CLDN4 promoter in ovarian cancer cells [J]. J. Biol. Chem, 2006, 281:21433–21444.
[91] Honda H. Regulation of the CLDN3 Gene in Ovarian Cancer Cells [J]. Cancer Biol. Ther, 2007,6:1733–1742.
[92] Strahl BD, Allis CD. The language of covalent histone modifications [J]. Nature. 2000,403:41-45.
[93] Kudo S. Methyl-CpG-binding protein MeCP2 represses Sp1-activated transcription of the human leukosialin gene when the promoter is methylated [J]. Mol. Cell. Biol, 1998,18: 5492-5499.
[94] Segal E, Fondufe-Mittendorf Y, Chen L, et al. A genomic code for nucleosome positioning [J].Nature, 2006,442:772-778.
[95] Struhl K. Histone acetylation and transcriptional regulatory mechanisms [J]. Genes Dev, 1998,12:599-606.
[96] Arabzadeh A, Troy TC, Turksen K. Role of the Cldn6 cytoplasmic tail domain in membrane targeting and epidermal differentiation in vivo [J]. Mol Cell Biol, 2006,26: 5876-5887.
[97] Troy TC, Rahbar R, Arabzadeh A, et al. Delayed epidermal permeability barrier formation and hair follicle aberrations in Inv-Cldn6 mice [J]. Mech Dev, 2005,122: 805-819.
[98] Agarwal R, D'Souza T, Morin PJ. CLDN3 and CLDN4 expression in ovarian epithelial cells enhances invasion and is associated with increased matrix metalloproteinase-2 activity[J]. Cancer Res, 2005,65: 7378-7385.
[99] Sourisseau T, Georgiadis A, Tsapara A, et al. Regulation of PCNA and cyclin D1 expression and epithelial morphogenesis by the ZO-1-regulated transcription factor ZONAB/DbpA [J]. Mol Cell Biol, 2006,26: 2387-2398.
[100] Mancini A, Koch A, Stefan M, et al. The direct association of the multiple PDZ domain containing proteins (MUPP-1) with the human c-Kit C-terminus is regulated by tyrosine kinase activity [J]. FEBS Lett, 2000,482: 54-58.
[101] Tokes AM, Kulka J, Paku S, et al. CLDN1, -3 and -4 proteins and mRNA expression in benign and malignant breast lesions: a research study [J]. Breast Cancer Res, 2005,7: 296-305.
[102] Kominsky SL, Argani P, Korz D, et al. Loss of the tight junction protein CLDN7 correlates with histological grade in both ductal carcinoma in situ and invasive ductalcarcinoma of the breast [J]. Oncogene, 2003,22:2021-2033.
[103] Roh MH, Margolis B. Composition and function of PDZ protein complexes during cell polarization [J]. Am J Physiol Renal Physiol, 2003,285: F377-387.
[104] Lemmers C, Medina E, Delgrossi MH, et al. hINADl/PATJ, a homolog of discs lost, interacts with crumbs and localizes to tight junctions in human epithelial cells [J]. J Biol Chem, 2002,277: 25408-25415.
[105] Ebihara C, Kondoh M, Hasuike N, et al. Preparation of a CLDNtargeting molecule using a C-terminal fragment of Clostridium perfringens enterotoxin [J]. J Pharmacol Exp Ther, 2006,316:255-260.
[106] Kominsky SL, Vali M, Korz D, et al. Clostridium perfringens enterotoxin elicits rapid and specific cytolysis of breast carcinoma cells mediated through tight junction proteins claudin 3 and 4 [J]. Am J Pathol, 2004,164:1627-1633.
[107] Katahira J, Sugiyama H, Inoue N, et al. Clostridium perfringens enterotoxin utilizes two structurally related membrane proteins as functional receptors in vivo [J]. J Biol Chem, 1997,272:26652-26658.
[108] Sonoda N, Furuse M, Sasaki H,et al. Clostridium perfringens enterotoxin fragment removes specific claudins from tight junction strands: Evidence for direct involvement of claudins in tight junction barrier [J]. J Cell Biol, 1999,147:195-204.
[109] Michl P, Buchholz M, Rolke M, et al. CLDN4: a new target for pancreatic cancer treatment using Clostridium perfringens enterotoxin [J]. Gastroenterology, 2001,121:678-684.
[110] Offner S, Hekele ., Teichmann U, et al. Epithelial tight junction proteins as potential antibody targets for pancarcinoma therapy [J]. Cancer Immunol Immunother, 2005 ,54: 431-445.
[111] Ye L, Martin TA, Parr C, Harrison GM, Mansel RE, Jiang WG. Biphasic effects of 17-beta-estradiol on expression of occludin and transendothelial resistance and paracellular permeability in human vascular endothelial cells [J]. J Cell Physiol, 2003,196: 362-369.
[112]吴琼,张海英,刘亚芳,等。紧密连接蛋白CLDN6在人乳腺癌细胞和组织中的表达及其与乳腺癌淋巴结转移的关系[J].吉林大学学报(医学版), 2008, 34:274-277.
[113] Piontek J, Winkler L, Wolburg H, et al. Formation of tight junction: determinants of homophilic interaction between classic claudins [J]. FASEB J, 2008,22:146-158.
[114] Blanco D, Vicent S, Elizegi E, et al. Altered expression of adhesion moleculesand epithelial-mesenchymal transition in silica-induced rat lung carcinogenesis [J]. Lab Invest, 2004,84:999-1012.
[115] Tsukita S, Furuse M, Itoh M. Multifunctional strands in tight junctions [J]. Nat Rev Mol Cell Biol, 2001, 2:285-293.
[116] Matter K, Balda MS. Signalling to and from tight junctions [J]. Nat Rev Mol Cell Biol, 2003,4:225-236.
[117] Oscar RC, Christina VI, Christoph R, et.al. Claudin extracellular domains determine paracellular charge selectivity and resistance but not tight junction fibril architecture [J]. Physiol Cell Physiol, 2003, 284(6): 1346-1354.
[118] Hong YH, Hishikawa D, Miyahara H, et.al. Up-regulation of the claudin-6 gene in adipogenesis [J]. Biosci Biotechnol Biochem, 2005,29:2117-2121.
[119] Moriwaki K, Tsukita S, Furuse M. Tight junctions containing claudin 4 and 6 are essential for blastocyst formation in preimplantation mouse embryos [J]. Dev Biol 2007,312: 509-522.
[120] Troy TC, Rahbar R, Arabzadeh A, et.al. Delayed epidermal permeability barrier formation and hair follicle aberrations in Inv-Cldn6 mice [J]. Mech Dev, 2005,122:805-819.
[121] Turksen K, Troy TC. Permeability barrier dysfunction in transgenic mice overexpressing claudin 6 [J]. Development, 2002,129:1775-1784.
[122] Lu SJ, Quan C. Identification of genes preferentially expressed in mammary epithelial cells of Copenhagen rat using subtractive hybridization and microarrays [J]. Carcinogenesis 2003; 24: 1593-1599.
[123] Wu Q, Liu Y, Ren Y, Xu X, Yu L, Li Y, Quan C. Tight junction protein, claudin-6, downregulates the malignant phenotype of breast carcinoma [J]. Eur J Cancer Prev, 2010, 19: 186-194.
[124] Hirohashi S. Inactivation of the E-cadherin-mediated cell adhesion system in human cancers [J]. Pathol, 1998,153: 333-339.
[125] Kominsky SL, Argani P, Korz D, et.al. Loss of the tight junction protein claudin-7 correlates with histological grade in both ductal carcinoma in situ and invasive ductal carcinoma of the breast [J]. Oncogene, 2003,22(13):2021-2033.
[126] Lee WH, Morton RA, Epstein JI, et al. Cytidine methylation of regulatory sequences near the pi-class glutathione Stransferase gene accompanies human prostatic carcinogenesis. Proc Natl Acad Sci U S A. 1994,91:11733-11737.
[127] Chen WD, Han ZJ, Skoletsky J, et al. Detection in fecal DNA of coloncancerspecific methylation of the nonexpressed vimentin gene [J]. J Natl Cancer Inst, 2005,97:1124-1132.
[128] Wei M, Xu J, Dignam J, et al. Olopade OI: Estrogen receptor alpha, BRCA1, and FANCF promoter methylation occur in distinct subsets of sporadic breast cancers [J]. Breast Cancer Res Treat, 2008,111:113-120.
[129] Bird A. DNA methylation patterns and epigenetic memory [J]. Genes Dev, 2002,16:6–21.
[130] Nan X, Campoy FJ, Bird, A. MeCP2 is a transcriptional repressor with abundant binding sites in genomic chromatin [J]. Cell, 1997,88 :471–481.
[131] Nan X, Ng HH, Johnson, CA, et al. Transcriptional repression by the methyl-CpG-binding protein MeCP2 involves a histone deacetylase complex [J]. Nature, 1998, 393:386-389.
[132] Igor NZ, Michael RM, Rodney JF, et al. CpG methylation attenuates Sp1 and Sp3 binding to the human extracellular superoxide dismutase promoter and regulates its cell-specific expression [J]. Free Radical Biology & Medicine, 2010,48:895-904.
[133] Gan CP, Hamid S, Hor SY, et al. Valproic acid: Growth inhibition of head and neck cancer by induction of terminal differentiation and senescence [J]. Head Neck, 2011,10(1002):1-11.
[134] Yoshitomi T, Kawakami K, Enokida H, et al. Restoration of miR-517a expression induces cell apoptosis in bladder cancer cell lines [J]. Oncol Rep. 2011,25(6):1661-8.
[135] Lin J, Haffner MC, Zhang Y, et al. Disulfiram is a DNA demethylating agent and inhibits prostate cancer cell growth [J]. Prostate, 2011,71(4):333-343.
[136] Cameron EE, Bachman KE, My?h?nen S, et al. Synergy of demethylation and histone deacetylase inhibition in the re-expression of genes silenced in cancer [J]. Nat Genet, 1999,21(1):103-107.
[137] Furuse M., Sasaki H., Tsukita S. Manner of interaction of heterogeneous claudin species within and between tight junction strands[J]. J Cell Biol, 1999, 147: 891-903.
[138] Van Itallie C., Rahner C., Anderson J.M. Regulated expression of CLDN4 decreases paracellular conductance through a selective decrease in sodium permeability[J]. J Clin Invest, 2001, 107: 1319-1327.
[139] Alexandre M.D., Lu Q., Chen Y.H. Overexpression of CLDN7 decreases the paracellular Cl- conductance and increases the paracellular Na+ conductance in LLC-PK1 cells[J]. J Cell Sci, 2005, 118: 2683-2693.
[2] Furuse M, Fujita K, Hiiragi T, et al. CLDN1 and -2: novel integral membrane proteins localizing at tight junctions with no sequence similarity to occluding [J]. J Cell Biol, 1998,141:1539-1550.
[3] Tsukita S, Sasaki H, Fujimoto K, et.al. A single gene product, claudin 1 or 2, reconstitutes tight junction strands and recruits occludin in fibroblasts [J]. Cell Biol, 1998,143: 391–401.
[4] Turksen K, Troy TC. Barriers built on claudins [J]. Cell Biol, 2004, 117: 2435-2447.
[5] Morita K, Furuse M, Fujimoto K, et.al. Claudin multigene family encoding four-transmembrane domain protein components of tight junction strands [J]. Proc. Natl. Acad. Sci. USA, 1999, 96:511–516.
[6] Oscar RC, Christina VI, Christoph R, et.al. Claudin extracellular domains determine paracellular charge selectivity and resistance but not tight junction fibril architecture [J]. Physiol Cell Physiol, 2003, 284(6): 1346-1354.
[7] Fujita K., Katahira J., Horiguchi Y., et al. Clostridium perfringens enterotoxin binds to the second extracellular loop of CLDN3, a tight junction integral membrane protein [J]. FEBS Lett, 2000,476:258-261.
[8] Van Itallie C M, Colegio O R., Anderson J M. The cytoplasmic tails of claudins can influence tight junction barrier properties through effects on protein stability [J]. J Membr Biol, 2004,199:29-38.
[9] Tsukita S, Furuse M, Itoh M. Multifunctional strands in tight junctions [J]. Nat Rev Mol Cell Biol, 2001, 2:285–293.
[10] Coyne C B, Gambling T M, Boucher R C, et al. Role of claudin interactions in airway tight junctional permeability [J]. Am J Physiol Lung Cell Mol Physiol, 2003,285:1166-1178.
[11] Kubota K, Furuse M, Sasaki H, et al. Ca2+-independent cell-adhesion activity of claudins, a family of integral membrane proteins localized at tight junctions [J]. Curr Biol, 1999,9(18): 1035-1038.
[12] Amasheh S, Schmidt T, Mahn M, et al. Contribution of CLDN5 to barrier properties in tight junctions of epithelial cells [J]. Cell Tissue Res, 2005, 321:89-96.
[13] Abuazza G, Becker A, Williams S S, et al. Claudins 6, 9, and 13 are developmentally expressed renal tight junction proteins [J]. Am J Physiol Renal Physiol, 2006,291:F1132-1141.
[14] Morita K, Furuse M, Fujimoto K, et.al. Claudin multigene family encoding four-transmembrane domain protein components of tight junction strands [J]. Proc. Natl. Acad. Sci. USA, 1999, 96:511–516.
[15] Aung PP, Mitani Y, Sanada Y, et.al. Differential expression of claudin-2 in normal human tissues and gastrointestinal carcinomas [J]. Virchows Arch, 2006,448(4):428-434.
[16] Morita K, Sasaki H, Furuse M, et al. Endothelial claudin: claudin- 5/TMVCF constitutes tight junction strands in endothelial cells[J]. J Cell Biol. 1999; 147(1): 185–194.
[17] Holmes J L, Itallie C, Rasmussen J E, et al. Claudin profiling in the mouse during postnatal intestinal development and along the gastrointestinal tract reveals complex expression patterns [J]. Gene Expr Patterns, 2006,6(6): 581–588.
[18] Rahner C, Mitic L L, Anderson J M. Heterogeneity in expression and subcellular localization of claudins 2, 3, 4, and 5 in the rat liver, pancreas, and gut [J] . Gastroenterology, 2001; 120(2): 411–422.
[19] Kiuchi-Saishin Y, Gotoh S, Furuse M, et al. Differential expression patterns of claudins, tight junction membrane proteins, in mouse nephron segments [J]. J Am Soc Nephrol. 2002; 13 (4): 875–886.
[20] Morohashi S, Kusumi T, Sato F, et al. Decreased expression of CLDN1 correlates with recurrence status in breast cancer [J]. Int J Mol Med, 2007, 20: 139-143.
[21] Miyamoto K, Kusumi T, Sato F, et al. Decreased expression of CLDN1 is correlated with recurrence status in esophageal squamous cell carcinoma [J]. Biomed Res, 2008, 29: 71-76.
[22] Miwa N, Furuse M, Tsukita S, et al. Involvement of CLDN1 in the beta-catenin/Tcf signaling pathway and its frequent upregulation in human colorectal cancers[J]. Oncol Res, 2001,12: 469-476.
[23] Dhawan P, Singh A B, Deane N G, et al. CLDN1 regulates cellular transformation and metastatic behavior in colon cancer [J]. J Clin Invest, 2005,115:1765-1776.
[24] Paschoud S, Bongiovanni M, Pache J C, et al. CLDN1 and CLDN5 expression patterns differentiate lung squamous cell carcinomas from adenocarcinomas [J]. Mod Pathol, 2007, 20: 947-954.
[25] Oku N, Sasabe E, Ueta E, et al. Tight junction protein CLDN1 enhances theinvasive activity of oral squamous cell carcinoma cells by promoting cleavage of laminin-5 gamma2 chain via matrix metalloproteinase (MMP)-2 and membrane-type MMP-1 [J]. Cancer Res,2006, 66: 5251-5257.
[26] Cohn M L, Goncharuk V N, Diwan A H, et al. Loss of CLDN1 expression in tumor-associated vessels correlates with acquisition of metastatic phenotype in melanocytic neoplasms [J]. J Cutan Pathol, 2005,32: 533-536.
[27] Aung P P, Mitani Y, Sanada Y, et al. Differential expression of CLDN2 in normal human tissues and gastrointestinal carcinomas [J]. Virchows Arch, 2006, 448: 428-434.
[28] Soini Y, Tommola S, Helin H, et al. Claudins 1, 3, 4 and 5 in gastric carcinoma, loss of claudin expression associates with the diffuse subtype [J]. Virchows Arch, 2006, 448: 52-58.
[29] Nacht M, Ferguson A T, Zhang W, et al. Combining serial analysis of gene expression and array technologies to identify genes differentially expressed in breast cancer [J]. Cancer Res, 1999,59:5464-5470.
[30] Hough C D, Sherman-Baust C A, Pizer E S, et al. Large-scale serial analysis of gene expression reveals genes differentially expressed in ovarian cancer [J]. Cancer Res, 2000,60: 6281-6287.
[31] Hewitt K J, Agarwal R, Morin P J. The claudin gene family: expression in normal and neoplastic tissues [J]. BMC Cancer, 2006,6:186.
[32] Takala H, Saarnio J, Wiik H, et al. Claudins 1, 3, 4, 5 and 7 in esophageal cancer: loss of claudin 3 and 4 expression is associated with metastatic behavior [J]. APMIS, 2007, 115: 838-847.
[33] Michl P, Barth C, Buchholz M, et al. CLDN4 expression decreases invasiveness and metastatic potential of pancreatic cancer [J]. Cancer Res, 2003,63: 6265-6271.
[34] Nichols LS, Ashfaq R, Iacobuzio-Donahue CA. Claudin 4 protein expression in primary and metastatic pancreatic cancer: support for use as a therapeutic target [J]. Am J Clin Pathol, 2004,121: 226-230.
[35] Vare P, Loikkanen I, Hirvikoski P, et al. Low claudin expression is associated with high Gleason grade in prostate adenocarcinoma [J]. Oncol Rep, 2008, 19: 25-31.
[36] Makoto O, Masaki M, Hideki C, et al. Epigenetic silencing of claudin-6 promotes anchorage-independent growth of breast carcinoma cells [J].Can Sci. 2007,98: 1557-62.
[37] Tsunoda S, Smith E. Methylation of CLDN6, FBN2, RBP1, RBP4, TFPI2, and TMEFF2 in esophageal squamous cell carcinoma [J]. Oncol Rep. 2009,21:1067-1073.
[38] Borlak J, Meier T, Halter R, et al. Epidermal growth factor-induced hepatocellular carcinoma: gene expression profiles in precursor lesions, early stage and solitary tumours [J]. Oncogene, 2005,24: 1809-1819.
[39] Tzelepi VN, Tsamandas AC, Vlotinou HD, et al. Tight junctions in thyroid carcinogenesis: diverse expression of CLDN1, CLDN4, CLDN7 and occludin in thyroid neoplasms [J]. Mod Pathol, 2008,21: 22-30.
[40] Adam H J, Henry F F, Alexander Z, et.al. Expression of Tight-Junction Protein Claudin-7 Is an Early Event in Gastric Tumorigenesis [J]. American Journal of Pathology, 2005, 167:577-584.
[41] Cheung ST, Leung KL, Ip YC, et al. CLDN10 expression level is associated with recurrence of primary hepatocellular carcinoma [J]. Clin Cancer Res, 2005, 11: 551-556.
[42] Nemeth Z, Szasz AM, Tatrai P, et al. CLDN1, -2, -3, -4, -7, -8, and -10 protein expression in biliary tract cancers [J]. J Histochem Cytochem, 2009, 57: 113-121.
[43] Kohno Y, Okamoto T, Ishibe T, et al. Expression of claudin7 is tightly associated with epithelial structures in synovial sarcomas and regulated by an Etsfamily transcription factor, ELF3 [J]. J Biol Chem, 2006, 281: 38941-38950.
[44] Rangel LB., Sherman-Baust CA, Wernyj RP, et al. Characterization of novelhuman ovarian cancer-specific transcripts (HOSTs) identified by serial analysis of gene expression [J]. Oncogene, 2003, 22:7225-7232.
[45] Yoshiki K, Takeshi O, Tatsuya I. Expression of Claudin 7 Is Tightly Associated with Epithelial Structures in Synovial Sarcomas and Regulated by an Ets Family Transcription Factor, ELF3 [J]. Biol. Chem, 2006, 281(50): 38941-38950.
[46] Ikenouchi J, Matsuda M, Furuse M, et al. Regulation of tight junctions during the epithelium–mesenchyme transition: direct repression of the gene expression of claudins/occludin by Snail [J]. Cell Sci, 2003,116: 1959–1967.
[47] D'Souza T, Agarwal R, Morin P J.Phosphorylation of claudin-3 at threonine 192 by cAMP-dependent protein kinase regulates tight junction barrier function in ovarian cancer cells [J]. Biol. Chem, 2005,280: 26233–26240.
[48] Ikari A, Matsumoto S, Harada H, et al. Phosphorylation of paracellin-1 at Ser217 by protein kinase A is essential for localization in tight junctions [J]. Cell Sci, 2006, 119: 1781–1789.
[49] Thompson GE. Cortisol and regulation of tight junctions in the mammary gland of the late-pregnant goa.t [J]. Dairy Res, 1996,63:305–308.
[50] Forster C, Makela S, Warri A, et al. Involvement of estrogen receptor ? in terminal differentiation of mammary gland epithelium [J]. Proc Natl Acad Sci USA, 2002, 99:15578–15583.
[51] Liu Yafang, Wu Qiong, Ren Yue, et al. Role of estrogen receptor-αin regulating claudin-6 expression in breast cancer cells [J]. J Breast Cancer 2011,14(1):20-27.
[52] Liu YF, Wu Q, Xu XM, et al. Effects of 17beta-estradiol on proliferation and migration of MCF-7 cell by regulating expression of claudin-6. Zhong hua Bing Li Xue Za Zhi [J]. 2010,39:44-47.
[53] Nakayama F, Semba S, Usami Y, et al. Hypermethylation-modulated downregulation of claudin-7 expression promotes the progression of colorectal carcinoma. Pathobiology [J]. 2008,75(3):177-85.
[54] Losel R, Wehling M, Jensen EV, et al. Estrogen receptors and proliferation markers in primary and recurrent breust caacett [J]. Proc Neff Aced Sci USA, 2001, 98(26): 15197-15202.
[55] Nilsson S, Makela S, Treuter E, et al. Mechanisms of estrogen action [J]. Physiol Rev Gustafsson, 2001,81:1535–1565.
[56] Gottlicher M, Heck S, Herrlich P. Transcriptional,cross-talk, the second mode of steroid hormone receptor action [J]. Mol Med, 1998, 76:480–489.
[57] Ito M, Weiss J. Estrogen receptor binding to DNA is not required for its activtiy through the nonclassical AP1 pathway [J]. Biol Chem, 2001, 276(17):13615-13621.
[58] Levin ER. Cellular functions of plasma membrane estrogen receptors [J]. Steroids, 2002, 67: 471-475.
[59] Blanchard AA, Skliris GP, Watson PH, et al. CLDNs 1, 3, and 4 protein expression in ER negative breast cancer correlates with markers of the basal phenotype. Virchows Arch 2009, 454: 647–656.
[60] Lin Y, Tracey AM, Christian P, et al. Biphasic effects of 17-β-estradiol on expression of occludin and transendothelial resistance and paracellular permeability in human vascular endothelial cells.[J]. Cell. Physiol, 2003, 196: 362-369.
[61] Shikhar Sharma, Theresa K. Epigenetics in cancer [J]. Carcinogenesis, 2010,1 : 27~36.
[62] Jones PA,Baylin SB. The fundamental role of epigenetic events in cancer [J]. Nat Rev Genet, 2002,3: 415-428.
[63] Klose RJ, Bird AP. Genomic DNA methylation:the mark and its mediators [J].Trends Biochem Sci. 2006;31:89-97.
[64] Glass JL, Thompson RF, Khulan B, et al.CG dinucleotide clustering is a speciesspecific property of the genome [J]. Nucleic Acids Res, 2007,35:6798-6807.
[65] Illingworth RS, Bird AP. CpG islands–‘a rough guide.’FEBS Lett. 2009;583:1713-1720.
[66] Adrian Bird. Perceptions of epigenetics [J].Nature, 2007, 447:396-398.
[67] Reik W, Dean W, Walter J. Epigenetic reprogramming in mammalian development [J]. Science, 2001,293:1089-1093.
[68] Morgan HD, Sutherland HG, Martin DI, et al. Epigenetic inheritance at the agouti locus in the mouse [J]. Nat Genet, 1999,23:314-318.
[69] Hu JL, Zhou BO,The N-terminus of histone H3 is required for de novo DNA methylation in chromatin [J]. Proc Natl Acad Sci USA, 200929,106(52):22187-92.
[70] Baylin, SB, Jones, P.A. Epigenetic determinants of cancer [J]. In Epigenetics, 2007:457-476.
[71] Ballestar E, and Esteller M. Epigenetic gene regulation in cancer [J]. Adv. Genet, 2008,61:247-267.
[72] Murayama A, Sakura K, Nakama M, et al. A specific CpG site demethylation in the human interleukin 2 gene promoter is an epigenetic memory [J]. EMBO J, 2006, 25:1081-1092.
[73] Ahmed H, Banerjee PP, Vasta GR. Differential expression of galectins in normal, benign and malignant prostate epithelial cells: Silencing of galectin-3 expression in prostate cancer by its promoter methylation [J]. Biochem Biophys Res, 2007, 358: 41-246.
[74] Kim JH, Hwang EH, Park HJ, et al. Methylation of CpG islands in the rat 7-dehydrocholesterol reductase promoter suppresses transcriptional activation [J]. Mol. Cells, 2005,19:279-282.
[75] Motegi K, Azuma M., Tamatani T, et al. Expression of aquaporin-5 in and fluid secretion from immortalized human salivary gland ductal cells by treatment with 5-aza-2′-deoxycytidine: a possibility for improvement of xerostomia in patients with Sjogren’s syndrome [J]. Lab. Invest, 2005, 85:342-353.
[76] Shikhar Sharma, Theresa K. Epigenetics in cancer [J]. Carcinogenesis, 2010,1:27-36.
[77] Singal R, Ginder G D. DNA methylation [J]. Blood, 1999, 93(12):4059-4070.
[78] McGough JM, Yang DF, Huang, S, et al. DNA methylation repressesIFN-gamma-induced and signal transducer and activator of transcription 1-mediated IFN regulatory factor 8 activation in colon carcinoma cells [J]. Mol. Cancer Res, 2008,6:1841-1851.
[79] Murayama A, Sakura K, Nakama M, et al. A specific CpG site demethylation in the human interleukin 2 gene promoter is an epigenetic memory [J]. EMBO J, 2006, 25:1081-1092.
[80] Clark SJ, Harrison J, Molloy PL. Sp1 binding is inhibited by (m)Cp(m)CpG methylation [J]. Gene, 1997,195: 67-71.
[81] Zhu WG, Srinivasan K, Dai ZY, et al. Methylation of adjacent CpG sites affects Sp1/Sp3 binding and activity in the p21(Cip1) promoter [J]. Mol. Cell. Biol, 2003,23: 4056-4065.
[82] Nan X, Ng HH, Johnson CA, et al. Transcriptional repression by the methyl-CpG-binding protein MeCP2 involves a histone deacetylase complex [J]. Nature, 1998,393:386-389.
[83] Cannistraro VJ, Taylor JS. Methyl CpG binding protein 2 (MeCP2) enhances photodimer formation at methyl-CpG sites but suppresses dimer deamination [J]. Nucleic Acids Res, 2010, 38(20):6943-6955.
[84] Dandrea M, Donadelli M, Costanzo C, et al. MeCP2/H3meK9 are involved in IL-6 gene silencing in pancreatic adenocarcinoma cell lines [J]. Nucleic Acids Research, 2009; 37(20):6681–90.
[85] Müller I, Wischnewski F, Pantel K, et al. Promoter- and cell-specific epigenetic regulation of CD44, Cyclin D2, GLIPR1 and PTEN by Methyl-CpG binding proteins and histone modifications [J]. BMC Cancer, 2010,17 (10) :297.
[86] Bowen NJ, Palmer MB, Wade PA. Chromosomal regulation by MeCP2: structural and enzymatic considerations [J]. Cell Mol. Life Sci, 2004,61: 2163-2167.
[87] Honda H, Pazin MJ, D'Souza T, et al. Regulation of the CLDN3 gene in ovarian cancer cells [J]. Cancer Biol Ther, 2007,6(11):1733-42.
[88] Stéphanie B, Michael B, Michael SS, et al. DNA-methylation-dependent alterations of claudin-4 expression in human bladder carcinoma [J]. Carcinogenesis, 2007 28(2):246-258.
[89] Litkouhi B. Claudin-4 overexpression in epithelial ovarian cancer is associated with hypomethylation and is a potential target for modulation of tight junction barrier function using a C-terminal fragment of Clostridium perfringens enterotoxin [J]. Neoplasia,2007,9:304-314.
[90] Honda H. Crucial roles of Sp1 and epigenetic modifications in the regulation of the CLDN4 promoter in ovarian cancer cells [J]. J. Biol. Chem, 2006, 281:21433–21444.
[91] Honda H. Regulation of the CLDN3 Gene in Ovarian Cancer Cells [J]. Cancer Biol. Ther, 2007,6:1733–1742.
[92] Strahl BD, Allis CD. The language of covalent histone modifications [J]. Nature. 2000,403:41-45.
[93] Kudo S. Methyl-CpG-binding protein MeCP2 represses Sp1-activated transcription of the human leukosialin gene when the promoter is methylated [J]. Mol. Cell. Biol, 1998,18: 5492-5499.
[94] Segal E, Fondufe-Mittendorf Y, Chen L, et al. A genomic code for nucleosome positioning [J].Nature, 2006,442:772-778.
[95] Struhl K. Histone acetylation and transcriptional regulatory mechanisms [J]. Genes Dev, 1998,12:599-606.
[96] Arabzadeh A, Troy TC, Turksen K. Role of the Cldn6 cytoplasmic tail domain in membrane targeting and epidermal differentiation in vivo [J]. Mol Cell Biol, 2006,26: 5876-5887.
[97] Troy TC, Rahbar R, Arabzadeh A, et al. Delayed epidermal permeability barrier formation and hair follicle aberrations in Inv-Cldn6 mice [J]. Mech Dev, 2005,122: 805-819.
[98] Agarwal R, D'Souza T, Morin PJ. CLDN3 and CLDN4 expression in ovarian epithelial cells enhances invasion and is associated with increased matrix metalloproteinase-2 activity[J]. Cancer Res, 2005,65: 7378-7385.
[99] Sourisseau T, Georgiadis A, Tsapara A, et al. Regulation of PCNA and cyclin D1 expression and epithelial morphogenesis by the ZO-1-regulated transcription factor ZONAB/DbpA [J]. Mol Cell Biol, 2006,26: 2387-2398.
[100] Mancini A, Koch A, Stefan M, et al. The direct association of the multiple PDZ domain containing proteins (MUPP-1) with the human c-Kit C-terminus is regulated by tyrosine kinase activity [J]. FEBS Lett, 2000,482: 54-58.
[101] Tokes AM, Kulka J, Paku S, et al. CLDN1, -3 and -4 proteins and mRNA expression in benign and malignant breast lesions: a research study [J]. Breast Cancer Res, 2005,7: 296-305.
[102] Kominsky SL, Argani P, Korz D, et al. Loss of the tight junction protein CLDN7 correlates with histological grade in both ductal carcinoma in situ and invasive ductalcarcinoma of the breast [J]. Oncogene, 2003,22:2021-2033.
[103] Roh MH, Margolis B. Composition and function of PDZ protein complexes during cell polarization [J]. Am J Physiol Renal Physiol, 2003,285: F377-387.
[104] Lemmers C, Medina E, Delgrossi MH, et al. hINADl/PATJ, a homolog of discs lost, interacts with crumbs and localizes to tight junctions in human epithelial cells [J]. J Biol Chem, 2002,277: 25408-25415.
[105] Ebihara C, Kondoh M, Hasuike N, et al. Preparation of a CLDNtargeting molecule using a C-terminal fragment of Clostridium perfringens enterotoxin [J]. J Pharmacol Exp Ther, 2006,316:255-260.
[106] Kominsky SL, Vali M, Korz D, et al. Clostridium perfringens enterotoxin elicits rapid and specific cytolysis of breast carcinoma cells mediated through tight junction proteins claudin 3 and 4 [J]. Am J Pathol, 2004,164:1627-1633.
[107] Katahira J, Sugiyama H, Inoue N, et al. Clostridium perfringens enterotoxin utilizes two structurally related membrane proteins as functional receptors in vivo [J]. J Biol Chem, 1997,272:26652-26658.
[108] Sonoda N, Furuse M, Sasaki H,et al. Clostridium perfringens enterotoxin fragment removes specific claudins from tight junction strands: Evidence for direct involvement of claudins in tight junction barrier [J]. J Cell Biol, 1999,147:195-204.
[109] Michl P, Buchholz M, Rolke M, et al. CLDN4: a new target for pancreatic cancer treatment using Clostridium perfringens enterotoxin [J]. Gastroenterology, 2001,121:678-684.
[110] Offner S, Hekele ., Teichmann U, et al. Epithelial tight junction proteins as potential antibody targets for pancarcinoma therapy [J]. Cancer Immunol Immunother, 2005 ,54: 431-445.
[111] Ye L, Martin TA, Parr C, Harrison GM, Mansel RE, Jiang WG. Biphasic effects of 17-beta-estradiol on expression of occludin and transendothelial resistance and paracellular permeability in human vascular endothelial cells [J]. J Cell Physiol, 2003,196: 362-369.
[112]吴琼,张海英,刘亚芳,等。紧密连接蛋白CLDN6在人乳腺癌细胞和组织中的表达及其与乳腺癌淋巴结转移的关系[J].吉林大学学报(医学版), 2008, 34:274-277.
[113] Piontek J, Winkler L, Wolburg H, et al. Formation of tight junction: determinants of homophilic interaction between classic claudins [J]. FASEB J, 2008,22:146-158.
[114] Blanco D, Vicent S, Elizegi E, et al. Altered expression of adhesion moleculesand epithelial-mesenchymal transition in silica-induced rat lung carcinogenesis [J]. Lab Invest, 2004,84:999-1012.
[115] Tsukita S, Furuse M, Itoh M. Multifunctional strands in tight junctions [J]. Nat Rev Mol Cell Biol, 2001, 2:285-293.
[116] Matter K, Balda MS. Signalling to and from tight junctions [J]. Nat Rev Mol Cell Biol, 2003,4:225-236.
[117] Oscar RC, Christina VI, Christoph R, et.al. Claudin extracellular domains determine paracellular charge selectivity and resistance but not tight junction fibril architecture [J]. Physiol Cell Physiol, 2003, 284(6): 1346-1354.
[118] Hong YH, Hishikawa D, Miyahara H, et.al. Up-regulation of the claudin-6 gene in adipogenesis [J]. Biosci Biotechnol Biochem, 2005,29:2117-2121.
[119] Moriwaki K, Tsukita S, Furuse M. Tight junctions containing claudin 4 and 6 are essential for blastocyst formation in preimplantation mouse embryos [J]. Dev Biol 2007,312: 509-522.
[120] Troy TC, Rahbar R, Arabzadeh A, et.al. Delayed epidermal permeability barrier formation and hair follicle aberrations in Inv-Cldn6 mice [J]. Mech Dev, 2005,122:805-819.
[121] Turksen K, Troy TC. Permeability barrier dysfunction in transgenic mice overexpressing claudin 6 [J]. Development, 2002,129:1775-1784.
[122] Lu SJ, Quan C. Identification of genes preferentially expressed in mammary epithelial cells of Copenhagen rat using subtractive hybridization and microarrays [J]. Carcinogenesis 2003; 24: 1593-1599.
[123] Wu Q, Liu Y, Ren Y, Xu X, Yu L, Li Y, Quan C. Tight junction protein, claudin-6, downregulates the malignant phenotype of breast carcinoma [J]. Eur J Cancer Prev, 2010, 19: 186-194.
[124] Hirohashi S. Inactivation of the E-cadherin-mediated cell adhesion system in human cancers [J]. Pathol, 1998,153: 333-339.
[125] Kominsky SL, Argani P, Korz D, et.al. Loss of the tight junction protein claudin-7 correlates with histological grade in both ductal carcinoma in situ and invasive ductal carcinoma of the breast [J]. Oncogene, 2003,22(13):2021-2033.
[126] Lee WH, Morton RA, Epstein JI, et al. Cytidine methylation of regulatory sequences near the pi-class glutathione Stransferase gene accompanies human prostatic carcinogenesis. Proc Natl Acad Sci U S A. 1994,91:11733-11737.
[127] Chen WD, Han ZJ, Skoletsky J, et al. Detection in fecal DNA of coloncancerspecific methylation of the nonexpressed vimentin gene [J]. J Natl Cancer Inst, 2005,97:1124-1132.
[128] Wei M, Xu J, Dignam J, et al. Olopade OI: Estrogen receptor alpha, BRCA1, and FANCF promoter methylation occur in distinct subsets of sporadic breast cancers [J]. Breast Cancer Res Treat, 2008,111:113-120.
[129] Bird A. DNA methylation patterns and epigenetic memory [J]. Genes Dev, 2002,16:6–21.
[130] Nan X, Campoy FJ, Bird, A. MeCP2 is a transcriptional repressor with abundant binding sites in genomic chromatin [J]. Cell, 1997,88 :471–481.
[131] Nan X, Ng HH, Johnson, CA, et al. Transcriptional repression by the methyl-CpG-binding protein MeCP2 involves a histone deacetylase complex [J]. Nature, 1998, 393:386-389.
[132] Igor NZ, Michael RM, Rodney JF, et al. CpG methylation attenuates Sp1 and Sp3 binding to the human extracellular superoxide dismutase promoter and regulates its cell-specific expression [J]. Free Radical Biology & Medicine, 2010,48:895-904.
[133] Gan CP, Hamid S, Hor SY, et al. Valproic acid: Growth inhibition of head and neck cancer by induction of terminal differentiation and senescence [J]. Head Neck, 2011,10(1002):1-11.
[134] Yoshitomi T, Kawakami K, Enokida H, et al. Restoration of miR-517a expression induces cell apoptosis in bladder cancer cell lines [J]. Oncol Rep. 2011,25(6):1661-8.
[135] Lin J, Haffner MC, Zhang Y, et al. Disulfiram is a DNA demethylating agent and inhibits prostate cancer cell growth [J]. Prostate, 2011,71(4):333-343.
[136] Cameron EE, Bachman KE, My?h?nen S, et al. Synergy of demethylation and histone deacetylase inhibition in the re-expression of genes silenced in cancer [J]. Nat Genet, 1999,21(1):103-107.
[137] Furuse M., Sasaki H., Tsukita S. Manner of interaction of heterogeneous claudin species within and between tight junction strands[J]. J Cell Biol, 1999, 147: 891-903.
[138] Van Itallie C., Rahner C., Anderson J.M. Regulated expression of CLDN4 decreases paracellular conductance through a selective decrease in sodium permeability[J]. J Clin Invest, 2001, 107: 1319-1327.
[139] Alexandre M.D., Lu Q., Chen Y.H. Overexpression of CLDN7 decreases the paracellular Cl- conductance and increases the paracellular Na+ conductance in LLC-PK1 cells[J]. J Cell Sci, 2005, 118: 2683-2693.