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Find video protocols related to scientific articles indexed in Pubmed.
[Promoter region methylation of DNA damage repair genes in human gastric cancer].
Zhonghua Yi Xue Za Zhi
PUBLISHED: 10-22-2014
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To detect the status of promoter region methylation of damage repair genes in gastric cancer and analyze its association with clinicopathologic characteristics.
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The miRNA network: micro-regulator of cell signaling in cancer.
Expert Rev Anticancer Ther
PUBLISHED: 08-28-2014
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The dysregulation of cell signaling plays a pivotal role in tumorigenesis and progression. miRNAs have been linked to almost all known aspects of physiological and pathological processes. It is well known that the miRNA network is linked at several and unexpected levels with cancer-related signaling pathways. Our understanding of the roles and regulation of the miRNA network has been extended to include classical cell signaling, termed miRNA network complements cell signaling in cancer. As a transcription factor, tumor suppressor p53 plays a central role in tumor prevention. Recent studies have demonstrated that miRNAs may regulate the expression of the p53 pathway or be regulated by the p53 pathway. These findings added a new and challenging layer of complexity to the p53 pathway and prompted us to contemplate the use of the compensatory mechanisms in therapeutics against cancer. In this review, we have therefore summarized the p53 tumor suppressive pathway as a typical paradigm to elucidate the advances of the compensatory mechanisms. We then go on to critically discuss how the compensatory mechanisms can be used to enable better cancer diagnosis and prognosis and to serve as potential therapeutic targets.
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DACH1 inhibits cyclin D1 expression, cellular proliferation and tumor growth of renal cancer cells.
J Hematol Oncol
PUBLISHED: 07-24-2014
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BackgroundRenal cell carcinoma (RCC) is a complex with diverse biological characteristics and distinct molecular signature. New target therapies to molecules that drive RCC initiation and progression have achieved promising responses in some patients, but the total effective rate is still far from satisfaction. Dachshund (DACH1) network is a key signaling pathway for kidney development and has recently been identified as a tumor suppressor in several cancer types. However, its role in renal cell carcinoma has not been fully investigated.MethodsImmunohistochemical staining for DACH1, PCNA and cyclin D1 was performed on human renal tissue microaraays and correlation with clinic-pathological characteristics was analyzed. In vitro proliferation, apoptosis and in vivo tumor growth were evaluated on human renal cancer cell lines with decitabine treatment or ectopic expression of DACH1. Downstream targets and potential molecular mechanism were investigated through western blot, immunoprecipitation and reporter gene assays.ResultsExpression of DACH1 was significantly decreased in human renal carcinoma tissue. DACH1 protein abundance was inversely correlated with the expression of PCNA and cyclin D1, tumor grade, and TNM stage. Restoration of DACH1 function in renal clear cell cancer cells inhibited in vitro cellular proliferation, S phase progression, clone formation, and in vivo tumor growth. In mechanism,DACH1 repressed cyclin D1 transcription through association with AP-1 protein.ConclusionOur results indicated that DACH1 was a novel molecular marker of RCC and it attributed to the malignant behavior of renal cancer cells. Re-activation of DACH1 may represent a potential therapeutic strategy.
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Transmembrane protein 106A is silenced by promoter region hypermethylation and suppresses gastric cancer growth by inducing apoptosis.
J. Cell. Mol. Med.
PUBLISHED: 05-21-2014
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Inactivation of tumour suppressor genes by promoter methylation plays an important role in the initiation and progression of gastric cancer (GC). Transmembrane 106A gene (TMEM106A) encodes a novel protein of previously unknown function. This study analysed the biological functions, epigenetic changes and the clinical significance of TMEM106A in GC. Data from experiments indicate that TMEM106A is a type II membrane protein, which is localized to mitochondria and the plasma membrane. TMEM106A was down-regulated or silenced by promoter region hypermethylation in GC cell lines, but expressed in normal gastric tissues. Overexpression of TMEM106A suppressed cell growth and induced apoptosis in GC cell lines, and retarded the growth of xenografts in nude mice. These effects were associated with the activation of caspase-2, caspase-9, and caspase-3, cleavage of BID and inactivation of poly (ADP-ribose) polymerase (PARP). In primary GC samples, loss or reduction of TMEM106A expression was associated with promoter region hypermethylation. TMEM106A was methylated in 88.6% (93/105) of primary GC and 18.1% (2/11) in cancer adjacent normal tissue samples. Further analysis suggested that TMEM106A methylation in primary GCs was significantly correlated with smoking and tumour metastasis. In conclusion, TMEM106A is frequently methylated in human GC. The expression of TMEM106A is regulated by promoter hypermethylation. TMEM106A is a novel functional tumour suppressor in gastric carcinogenesis.
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Epigenetic silencing of RASSF10 promotes tumor growth in esophageal squamous cell carcinoma.
Discov Med
PUBLISHED: 04-25-2014
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Esophageal squamous cell carcinoma (ESCC) is one of the most malignant diseases and the five year survival rate remains less than 10%. RASSF10 is a newly identified member of the Ras-association family, but the regulation and the function of RASSF10 in ESCC remain unclear. Research methodologies such as methylation specific PCR (MSP), semi-quantitative RT-PCR, immunohistochemistry, Sodium bisulfite sequencing, and colony formation assay were utilized in this investigation. Loss of RASSF10 expression was found in KYSE150 cells and reduced expression was found in KYSE70 and KYSE180 cells. Expression of RASSF10 was found in KYSE140, KYSE450, KYSE510, TE1, TE3, and TE8 cell lines. Complete methylation was found in KYSE30 and KYSE150 cells, partial methylation was found in KYSE70, KYSE180, KYSE510, and TE1, and unmethylation was found in KYSE140, KYSE450, TE3, and TE8. Re-expression or increased expression was induced by 5-Aza-dC treatment. RASSF10 was methylated in 44.3% primary esophageal squamous cell carcinoma. RASSF10 inhibits cell proliferation and induces G2/M phase arrest in esophageal cancer cells. In conclusion: RASSF10 was frequently methylated in human esophageal squamous cell carcinoma and expression of RASSF10 was regulated by promoter region hypermethylation. RASSF10 may serve as a tumor suppressor of esophageal cancer.
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Epigenetic silencing of DACH1 induces the invasion and metastasis of gastric cancer by activating TGF-? signalling.
J. Cell. Mol. Med.
PUBLISHED: 04-23-2014
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Gastric cancer (GC) is the fourth most common malignancy in males and the fifth most common malignancy in females worldwide. DACH1 is frequently methylated in hepatic and colorectal cancer. To further understand the regulation and mechanism of DACH1 in GC, eight GC cell lines, eight cases of normal gastric mucosa, 98 cases of primary GC and 50 cases of adjacent non-tumour tissues were examined. Methylation-specific PCR, western blot, transwell assay and xenograft mice were used in this study. Loss of DACH1 expression correlated with promoter region methylation in GC cells, and re-expression was induced by 5-Aza-2'-deoxyazacytidine. DACH1 is methylated in 63.3% (62/98) of primary GC and 38% (19/50) of adjacent non-tumour tissues, while no methylation was found in normal gastric mucosa. Methylation of DACH1 correlated with reduced expression of DACH1 (P < 0.01), late tumour stage (stage III/IV) (P < 0.01) and lymph node metastasis (P < 0.05). DACH1 expression inhibited epithelial-mesenchymal transition and metastasis by inhibiting transforming growth factor (TGF)-? signalling and suppressed GC cell proliferation through inducing G2/M phase arrest. The tumour size is smaller in DACH1-expressed BGC823 cell xenograft mice than in unexpressed group (P < 0.01). Restoration of DACH1 expression also sensitized GC cells to docetaxel. These studies suggest that DACH1 is frequently methylated in human GC and expression of DACH1 was controlled by promoter region methylation. DACH1 suppresses GC proliferation, invasion and metastasis by inhibiting TGF-? signalling pathways both in vitro and in vivo. Epigenetic silencing DACH1 may induce GC cells' resistance to docetaxel.
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Predictive value of CHFR and MLH1 methylation in human gastric cancer.
Gastric Cancer
PUBLISHED: 03-09-2014
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Gastric carcinoma (GC) has one of the highest mortality rates of cancer diseases and has a high incidence rate in China. Palliative chemotherapy is the main treatment for advanced gastric cancer. It is necessary to compare the effectiveness and toxicities of different regimens. This study explores the possibility of methylation of DNA damage repair genes serving as a prognostic and chemo-sensitive marker in human gastric cancer.
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MicroRNA-155 is involved in the pathogenesis of ulcerative colitis by targeting FOXO3a.
Inflamm. Bowel Dis.
PUBLISHED: 03-04-2014
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MicroRNAs (miRNAs) are important posttranscriptional regulators of gene expression. The precise role of miRNAs in ulcerative colitis (UC) is not completely understood. The purpose of this study was to identify miRNAs that are induced in patients with active UC and to assess the effect of miR-155 on improving intestinal inflammation.
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Epigenetic changes associated with neoplasms of the exocrine and endocrine pancreas.
Discov Med
PUBLISHED: 02-19-2014
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Early detection and multi-modality curative treatment for pancreatic cancer remain unsatisfactory due to the insufficient understanding of the mechanisms underlying tumor progression. Epigenetic events, including aberrant methylation of tumor suppressor gene promoter regions, may contribute to tumorigenesis involving both the exocrine and endocrine pancreas. Methylation changes of specific gene promoter regions were examined in 48 resected neoplasms of the exocrine and endocrine pancreas, which were obtained as paraffin-embedded tissue samples. The pancreatic neoplasms included acinar cell carcinoma (n=12), adenocarcinoma (n=18), and islet cell tumors (n=18). DNA methylation was determined with a nested methylation-specific PCR (MSP) technique incorporating an initial bisulfite modification of tumor DNA for the promoter regions associated with 14 tumor suppressor genes. In decreasing order, the 6 most frequently methylated genes were: APC 50%, BRCA1 46%, p16INK4a 35%, p15INK4b 35%, RAR? 35%, and p73 33%. Overall, 94% of the tumors had methylation of at least one gene, and methylation of two or more genes was present in 69% of pancreatic tumors. Pancreatic adenocarcinomas had patterns of gene methylation that differed from pancreatic endocrine tumors. These differences were most notable for the APC and hMLH1 genes.
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Methylation of DACT2 Promotes Papillary Thyroid Cancer Metastasis by Activating Wnt Signaling.
PLoS ONE
PUBLISHED: 01-01-2014
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Thyroid cancer is the most common endocrine malignant disease and the incidence is increasing. DACT2 was found frequently methylated in human lung cancer and hepatocellular carcinoma. To explore the epigenetic change and the role of DACT2 in thyroid cancer, 7 thyroid cancer cell lines, 10 cases of non-cancerous thyroid tissue samples and 99 cases of primary thyroid cancer samples were involved in this study. DACT2 was expressed and unmethylated in K1, SW579, FTC-133, TT, W3 and 8505C cell lines. Loss of expression and complete methylation was found in TPC-1 cells. Restoration of DACT2 expression was induced by 5-aza-2'deoxycytidine treatment. It demonstrates that the expression of DACT2 was regulated by promoter region methylation. In human primary papillary thyroid cancer, 64.6% (64/99) was methylated and methylation of DACT2 was related to lymph node metastasis (p<0.01). Re-expression of DACT2 suppresses cell proliferation, invasion and migration in TPC-1 cells. The activity of TCF/LEF was inhibited by DACT2 in wild-type or mutant ?-catenin cells. The activity of TCF/LEF was increased by co-transfecting DACT2 and Dvl2 in wild-type or mutant ?-catenin cells. Overexpression of wild-type ?-catenin promotes cell migration and invasion in DACT2 stably expressed cells. The expression of ?-catenin, c-myc, cyclinD1 and MMP-9 were decreased and the level of phosphorylated ?-catenin (p-?-catenin) was increased after restoration of DACT2 expression in TPC-1 cells. The expression of ?-catenin, c-myc, cyclinD1 and MMP-9 were increased and the level of p-?-catenin was reduced after knockdown of DACT2 in W3 and SW579 cells. These results suggest that DACT2 suppresses human papillary thyroid cancer growth and metastasis by inhibiting Wnt signaling. In conclusion, DACT2 is frequently methylated in papillary thyroid cancer. DACT2 expression was regulated by promoter region methylation. DACT2 suppresses papillary thyroid cancer proliferation and metastasis by inhibiting Wnt signaling.
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Silencing DACH1 promotes esophageal cancer growth by inhibiting TGF-? signaling.
PLoS ONE
PUBLISHED: 01-01-2014
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Human Dachshund homologue 1 (DACH1) is a major component of the Retinal Determination Gene Network. Loss of DACH1 expression was found in breast, prostate, lung, endometrial, colorectal and hepatocellular carcinoma. To explore the expression, regulation and function of DACH1 in human esophageal cancer, 11 esophageal cancer cell lines, 10 cases of normal esophageal mucosa, 51 cases of different grades of dysplasia and 104 cases of primary esophageal squamous cancer were employed. Methylation specific PCR, immunohistochemistry, western blot, flow cytometry, small interfering RNAs, colony formation techniques and xenograft mice model were used. We found that DACH1 expression was regulated by promoter region hypermethylation in esophageal cancer cell lines. 18.8% (6 of 32) of grade 1, 42.1% (8 of 19) of grade 2 and grade 3 dysplasia (ED2,3), and 61.5% (64 of 104) of esophageal cancer were methylated, but no methylation was found in 10 cases of normal esophageal mucosa. The methylation was increased in progression tendency during esophageal carcinogenesis (P<0.01). DACH1 methylation was associated with poor differentiation (P<0.05) and late tumor stage (P<0.05). Restoration of DACH1 expression inhibited cell growth and activated TGF-? signaling in KYSE150 and KYSE510 cells. DACH1 suppressed human esophageal cancer cell tumor growth in xenograft mice. In conclusion, DACH1 is frequently methylated in human esophageal cancer and methylation of DACH1 is involved in the early stage of esophageal carcinogenesis. DACH1 expression is regulated by promoter region hypermethylation. DACH1 suppresses esophageal cancer growth by activating TGF-? signaling.
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Epigenetic regulation of DACH1, a novel Wnt signaling component in colorectal cancer.
Epigenetics
PUBLISHED: 10-22-2013
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Colorectal cancer (CRC) is one of the common malignant tumors worldwide. Both genetic and epigenetic changes are regarded as important factors of colorectal carcinogenesis. Loss of DACH1 expression was found in breast, prostate, and endometrial cancer. To analyze the regulation and function of DACH1 in CRC, 5 colorectal cancer cell lines, 8 cases of normal mucosa, 15 cases of polyps and 100 cases of primary CRC were employed in this study. In CRC cell lines, loss of DACH1 expression was correlated with promoter region hypermethylation, and re-expression of DACH1 was induced by 5-Aza-2-deoxyazacytidine treatment. We found that DACH1 was frequently methylated in primary CRC and this methylation was associated with reduction in DACH1 expression. These results suggest that DACH1 expression is regulated by promoter region hypermethylation in CRC. DACH1 methylation was associated with late tumor stage, poor differentiation, and lymph node metastasis. Re-expression of DACH1 reduced TCF/LEF luciferase reporter activity and inhibited the expression of Wnt signaling downstream targets (c-Myc and cyclinD1). In xenografts of HCT116 cells in which DACH1 was re-expressed, tumor size was smaller than in controls. In addition, restoration of DACH1 expression induced G2/M phase arrest and sensitized HCT116 cells to docetaxel. DACH1 suppresses CRC growth by inhibiting Wnt signaling both in vitro and in vivo. Silencing of DACH1 expression caused resistance of CRC cells to docetaxel. In conclusion, DACH1 is frequently methylated in human CRC and methylation of DACH1 may serve as detective and prognostic marker in CRC.
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Epigenetic silencing of CXCL14 induced colorectal cancer migration and invasion.
Discov Med
PUBLISHED: 10-09-2013
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To explore epigenetic regulation and the impact of chemokine CXCL14 on colorectal cancer, 7 colorectal cancer cell lines, 107 cases of primary colorectal cancer, and 10 cases of normal colorectal mucosa were evaluated in this study. Methylation specific PCR (MSP), semi-quantitative reverse-transcription PCR (RT-PCR), cell proliferation assay, colony formation, and transwell assay were performed for the evaluation. Complete methylation and loss of CXCL14 expression were found in 5 colorectal cancer cell lines. Partial methylation and weak expression were found in two cell lines. CXCL14 was methylated in 79.4% (85/107) of primary human colorectal cancer. No methylation was found in 10 cases of normal colorectal mucosa. Restoration of CXCL14 expression was induced by the 5-aza-2-deoxycytidine (DAC) treatment. The cell viability was reduced and colony formation was inhibited by restoration of CXCL14 expression in HCT116 cells, a colorectal cancer cell line. The number of invasive and migration cells was reduced by CXCL14. The expression of MMP-2, Vimentin, and NF-?B was suppressed, and the expression of E-cadherin and I?B-? was induced by CXCL14. In conclusion, CXCL14 is frequently methylated in human colorectal cancer and promoter region hypermethylation silenced CXCL14 expression in colorectal cancer cells. Restoration of CXCL14 expression suppressed colorectal cancer proliferation. CXCL14 inhibits colorectal cancer migration, invasion, and epithelial-to-mesenchymal transition (EMT) by suppressing NF-?B signaling.
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Real-time contrast-enhanced ultrasound in diagnosis of solid renal lesions.
Discov Med
PUBLISHED: 08-06-2013
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The purpose of this study was to investigate the efficacy of contrast-enhanced ultrasound (CEUS) in diagnosis of solid renal lesions (SRLs)--malignant or benign renal tumors. We retrospectively analyzed 91 cases with 100 SLRs with a mean diameter of 3.3±1.7 cm. CEUS was performed and their perfusion characteristics were analyzed by using contrast pulse sequences technique. CEUS findings were compared with histopathologic findings of biopsy. There were 85 malignant lesions (78 renal clear cell carcinoma, 5 renal papillary carcinoma, and 2 chromophobe cell carcinoma) and 15 benign lesions (13 angiomyolipoma and 2 renal oncocytoma). For malignancy, 74 lesions (87.1%) showed contrast agent fast perfusing and hyper-enhancement or iso-enhancement in cortical phase and 72 (84.7%) showed hypo-enhancement in later corticomedullary or late phase. For tumors with a diameter>4 cm, the heterogeneous enhancement feature was shown seemingly as "honeycomb" enhancement; for those?4 cm, relatively homogeneous enhancement feature was observed. Meanwhile, 79 (92.9%) malignant lesions showed rim-like enhancement. For benignancy, 13 angiomyolipoma showed contrast agent slow wash-in and slow wash-out mode, while 2 renal oncocytoma showed similar enhancement characteristic to the malignant lesions. The specificity, accuracy, and positive predictive value of diagnosis for SRLs were 96.5%, 96%, and 82.4% for CEUS, and 72.9%, 71%, and 28.1% for conventional US, respectively (P<0.001). Meanwhile the sensitivity and negative predictive value for CEUS were 93.3% and 98.8%, respectively, compared with those of conventional US (60% and 91.2%, P>0.05). Real-time CEUS can provide valuable information for improving the diagnosis and differential diagnosis of SRLs.
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Glycoproteomic analysis of tissues from patients with colon cancer using lectin microarrays and nanoLC-MS/MS.
Mol Biosyst
PUBLISHED: 04-09-2013
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The current study evaluated the glycoproteomic profile of tissues from colon cancer patients. The lectin microarray was first performed to compare the glycoprotein profiles between colon cancer and matched normal tissues. Level of N-acetylglucosamine (GlcNAc) that Solanum tuberosum lectin (STL) bound was found to be elevated in colon cancer, which was verified through lectin histochemistry. The subsequent glycoproteomic analysis based on STL enrichment of glycoproteins followed by label-free quantitative nano liquid chromatography-mass spectrometry/mass spectrometry (nanoLC-MS/MS) analysis identified 72 proteins in high confidence. Among these proteins, 17 were exclusively detected in cancer tissues, and 14 were significantly upregulated in tumor tissues. Annexin A1 and HSP90? were chosen for further investigation by immunoprecipitation coupled with lectin blots, western blots and tissue microarrays. Both Annexin A1 and HSP90? were GlcNAcylated, and their protein expressions were elevated in colon cancer, compared to normal tissues. Moreover, specific changes of GlcNAc abundances in Annexin A1 and HSP90? suggested that tumor-specific glycan patterns could serve as candidate biomarkers of colon cancer for distinguishing cancer patients from healthy individuals.
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Epigenetic regulation of the Wnt signaling inhibitor DACT2 in human hepatocellular carcinoma.
Epigenetics
PUBLISHED: 02-28-2013
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DACT2 (Dapper, Dishevelled-associated antagonist of ?-catenin homolog 2) is a member of the DACT family involved in the regulation of embryonic development. Human DACT2 is localized on 6q27, a region of frequent loss of heterozygosity in human cancers. However, the regulation of DACT2 expression and function in hepatocellular carcinoma (HCC) remains unclear. In this study, genetic and epigenetic changes of DACT2 were analyzed in HCC cell lines and primary cancer. We found no single-nucleotide polymorphism (SNP) associated with HCC. Promoter region methylation was correlated with loss or reduction of DACT2 expression, and restoration of DACT2 expression was induced by 5-aza-2-deoxycytidine (5-AZA) in HCC cell lines. Promoter region methylation was found in 54.84% of primary HCC. Reduction of DACT2 expression was associated with promoter hypermethylation, and expression of DACT2 was inversely related to ?-catenin expression in primary HCC. DACT2 suppressed cell proliferation, induced G 2-M arrest in cell lines and inhibited tumor growth in xenograft nude mice. The transcriptional activity of TCF-4 and the expression of Wnt signaling downstream genes were suppressed by DACT2 re-expression and reactivated by depletion of DACT2. In conclusion, DACT2 is frequently methylated in HCC and its expression is regulated by promoter hypermethylation. DACT2 suppresses HCC by inhibiting Wnt signaling in human HCC.
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Methylation-mediated repression of microRNA 129-2 enhances oncogenic SOX4 expression in HCC.
Liver Int.
PUBLISHED: 02-14-2013
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Aberration of miR-129-2 has been linked to a variety of human tumours. However, whether miR-129-2 is involved in hepatocarcinogenesis remains unknown. Here, we investigate the involvement of miR-129-2 in HBV infection-related HCC.
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Epigenetic regulation of DACT2, a key component of the Wnt signalling pathway in human lung cancer.
J. Pathol.
PUBLISHED: 02-13-2013
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Dapper, Dishevelled-associated antagonist of ?-catenin (DACT), is involved in Xenopus embryonic development. Human DACT2 is localized on chromosome 6q27, a region of frequent loss of heterozygosity (LOH) in human cancers. However, the function and regulation of DACT2 in human lung cancer remain unclear. DNA sequencing, methylation-specific PCR (MSP), semi-quantitative RT-PCR, western blotting, and xenograft models were employed in this study. Eight lung cancer cell lines, 106 cases of primary lung cancer, four specimens of normal lung from patients without cancer, and 99 blood samples from healthy individuals were examined. We found that while there was no SNP related to lung cancer, the DACT2 promoter region is frequently methylated in human lung cancer. DACT2 is silenced by promoter region hypermethylation and re-expressed by 5-aza-2-deoxyazacytidine treatment of lung cancer cell lines. Methylation of DACT2 was associated with poor differentiation of lung cancer. Loss of DACT2 expression was associated with promoter region hypermethylation in primary lung cancer, and was associated with increased ?-catenin expression. Restoration of DACT2 expression suppressed tumour proliferation both in vitro and in vivo. DACT2 expression was down-regulated by siRNA knockdown in H727 cells. DACT2 inhibited T-cell factor/lymphoid enhancer factor (TCF/LEF) and its downstream genes. In conclusion, DACT2 methylation is a potential lung cancer detection marker. DACT2 is regulated by promoter region hypermethylation. DACT2 inhibits lung cancer proliferation by suppressing the Wnt signalling pathway in lung cancer.
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Epigenetic silencing of DACH1 induces loss of transforming growth factor-?1 antiproliferative response in human hepatocellular carcinoma.
Hepatology
PUBLISHED: 01-20-2013
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Human dachshund homolog 1 (DACH1) is a major component of the Retinal Determination Gene Network (RDGN) and functions as a tumor suppressor. However, the regulation of DACH1 expression and its function in hepatocellular carcinoma (HCC) remain unclear. In this study, epigenetic changes of DACH1 were analyzed in HCC cell lines and primary cancers. We found that promoter region hypermethylation was correlated with loss or reduction of DACH1 expression, and restoration of DACH1 expression was induced by 5-aza-2-deoxycytidine (5-AZA) in HCC cell lines. Promoter region methylation was found in 42% of primary HCC. Reduced expression of DACH1 was associated with poor differentiation of HCC nodules and higher serum aspartate aminotransferase/alanine aminotransferase ratio. DACH1 suppressed cellular growth by reactivating transforming growth factor beta (TGF-?) signaling. Ectopic expression of DACH1 enhanced chemosensitivity to 5-fluorouracil (5-FU) by inducing p21 expression in HCC cells. Conclusion: DACH1 is frequently methylated in HCC and DACH1 expression is regulated by promoter hypermethylation. Down-regulation of DACH1 is a novel mechanism for gaining resistance to the antiproliferative signaling of TGF-?1 and 5-FU resistance. (Hepatology 2013; 58:2012-2022).
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miR-127 Regulates Cell Proliferation and Senescence by Targeting BCL6.
PLoS ONE
PUBLISHED: 01-01-2013
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Cellular senescence occurs as a response to extracellular and intracellular stresses and contributes to aging and age-related pathologies. Emerging evidence suggests that cellular senescence also acts as a potent tumor suppression mechanism that prevents the oncogenic transformation of primary human cells. Recent reports have indicated that miRNAsact as key modulators of cellular senescence by targeting critical regulators of the senescence pathways. We previously reported that miR-127 is up-regulated in senescent fibroblasts. In this report, we identified miR-127 as a novel regulator of cellular senescence that directly targets BCL6. We further showed that miR-127 is down-regulated in breast cancer tissuesand that this down-regulation is associated with up-regulation of BCL6. Over-expression of miR-127 or depletion of BCL6 inhibits breast cancer cell proliferation. Our data suggest that miR-127 may function as a tumor suppressor that modulates the oncogene BCL6.
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Randomized phase II trial of lyophilized strawberries in patients with dysplastic precancerous lesions of the esophagus.
Cancer Prev Res (Phila)
PUBLISHED: 12-01-2011
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Dysplasia is a histologic precursor of esophageal squamous cell carcinoma (SCC). We previously showed that dietary freeze-dried, or lyophilized, strawberry powder inhibits N-nitrosomethylbenzylamine-induced SCC in the rat esophagus. On the basis of this observation, we conducted a randomized (noncomparative) phase II trial in China to investigate the effects of two doses of freeze-dried strawberries in patients with esophageal dysplastic lesions in a high-risk area for esophageal cancer. We randomly assigned 75 patients identified by endoscopy to have dysplastic esophageal premalignant lesions to receive freeze-dried strawberry powder at either 30 g/d (37 patients) or 60 g/d (38 patients) for six months; the powder was mixed with water and drunk. After six months, we assessed the changes in histologic grade of these lesions (primary endpoint) in a blinded fashion. The dose of 30 g/d, did not significantly affect histology or any other measured parameter. The dose of 60 g/d, however, reduced the histologic grade of dysplastic premalignant lesions in 29 (80.6%) of the 36 patients at this dose who were evaluated for histology (P < 0.0001). The strawberry powder was well tolerated, with no toxic effects or serious adverse events. Strawberries (60 g/d) also reduced protein expression levels of inducible nitric oxide synthase (iNOS) by 79.5% (P < 0.001), cyclooxygenase-2 (COX-2) by 62.9% (P < 0.001), phospho-nuclear factor kappa B (NF?B)-p65 (pNF?B-p65) by 62.6% (P < 0.001), and phospho-S6 (pS6) by 73.2% (P < 0.001). Freeze-dried strawberries (60 g/d) also significantly inhibited the Ki-67 labeling index by 37.9% (P = 0.023). Our present results indicate the potential of freeze-dried strawberry powder for preventing human esophageal cancer, supporting further clinical testing of this natural agent in this setting.
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Epigenetic changes in colorectal cancer.
Chin J Cancer
PUBLISHED: 11-04-2011
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Epigenetic changes frequently occur in human colorectal cancer. Genomic global hypomethylation, gene promoter region hypermethylation, histone modifications, and alteration of miRNA patterns are major epigenetic changes in colorectal cancer. Loss of imprinting(LOI) is associated with colorectal neoplasia. Folate deficiency may cause colorectal carcinogenesis by inducing gene-specific hypermethylation and genomic global hypomethylation. HDAC inhibitors and demethylating agents have been approved by the FDA for myelodysplastic syndrome and leukemia treatment. Non-coding RNA is regarded as another kind of epigenetic marker in colorectal cancer. This review is mainly focused on DNA methylation, histone modification, and microRNA changes in colorectal cancer.
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5-aza-2-deoxycytidine activates iron uptake and heme biosynthesis by increasing c-Myc nuclear localization and binding to the E-boxes of transferrin receptor 1 (TfR1) and ferrochelatase (Fech) genes.
J. Biol. Chem.
PUBLISHED: 09-07-2011
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The hypomethylating agent 5-aza-2-deoxycytidine (5-aza-CdR) and its derivatives have been successfully used for the treatment of myelodysplastic syndromes, and they frequently improve the anemia that usually accompanies these disorders. However, the molecular mechanisms underlying this action remain poorly understood. In this study, we used two erythroid models, murine erythroid leukemia cells and erythroid burst-forming unit-derived erythroblasts, to show that 5-aza-CdR induced erythroid differentiation and increased the expression of transferrin receptor 1 (TfR1) and ferrochelatase (Fech), thereby increasing iron uptake and heme biosynthesis. We have identified new regulatory E-boxes that lie outside of CpG islands in the TfR1 and Fech promoters, and the methylation status of these sites can be altered by 5-aza-CdR treatment. This in turn altered the binding of the transcription factor c-Myc to these promoter elements. Furthermore, 5-aza-CdR promoted the nuclear translocation of c-Myc and its binding to Max to form functional complexes. The coordinated actions of 5-aza-CdR on the methylation status of the target genes and in stimulating the nuclear translocation of c-Myc provide new molecular insights into the regulation of E-boxes and explain, at least in part, the increased erythroid response to 5-aza-CdR treatment.
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AKT signaling pathway activated by HIN-1 methylation in non-small cell lung cancer.
Tumour Biol.
PUBLISHED: 08-10-2011
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The purpose of this study is to determine the epigenetic changes and function of High in Normal-1 (HIN-1) in non-small cell lung cancer (NSCLC). HIN-1 expression was examined by semiquantitative RT-PCR before and after 5-aza-2-deoxycytidine (5-aza) treatment in NSCLC cell lines. Promoter methylation status of HIN-1 was tested by methylation-specific PCR (MSP). Effect of forced expression of HIN-1 on different key molecules of AKT signaling pathway was tested by Western Blot analysis in H157 and H23 cell lines. Promoter methylations are inversely correlated with expression of HIN-1 in eight (H23, H157, 95D, H1299, H358, H1752, H460, A549) of ten NSCLC cell lines and re-expression was observed by 5-aza treatment. We then tested promoter methylation of HIN-1 in primary NSCLC tissues. Methylation was detected in 73 out of 152 (48%) NSCLC cases. Forced expression of HIN-1 in NSCLC cell lines inhibited colony formation and induce apoptosis. Furthermore, overexpression of HIN-1 reduces the expression of phosphorated-AKT (p-AKT), c-myc, Bcl-2 and cyclinD1 while Bax was increased. Our data suggest that HIN-1 is a potential tumor suppressor gene in NSCLC, silenced by promoter hypermethylation and negatively regulate AKT signaling pathway.
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Differential expression of oncogenic miRNAs in proliferating and senescent human fibroblasts.
Mol. Cell. Biochem.
PUBLISHED: 02-24-2011
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miRNAs are a class of non-coding RNAs that play fundamental roles through the post-transcriptional regulation of target mRNAs. miRNAs have been shown to regulate a broad spectrum of biological activities, including development, differentiation, cell death, and oncogenesis. However, little is known about their contribution to cellular senescence. The authors analyzed the expression of 576 miRNAs in proliferating and senescent normal human fibroblasts by microarray, and identified 12 miRNAs that were differentially expressed in proliferating and senescent fibroblasts. Interestingly, all six miRNAs that were down-regulated in senescent cells had been previously reported to be aberrantly expressed in tumor cells. It was further showed that inhibition of miR-17-5p and miR-20a by 2-O-methyl antisense oligoribonucleotides resulted in the induction of senescent phenotypes in WI-38 cells.
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Effects of simulated weightlessness on tight junction protein occludin and Zonula Occluden-1 expression levels in the intestinal mucosa of rats.
J. Huazhong Univ. Sci. Technol. Med. Sci.
PUBLISHED: 02-19-2011
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This study investigated the tight junction (TJ) protein expression of the intestinal mucosa in a rat tail-suspension model under simulated weightlessness. Twenty-four Wistar rats were randomly divided into three groups: CON group (n=8), control; SUS-14 d group (n=8), tail-suspension for 14 days; SUS-21 d group (n=8), tail-suspension for 21 days. Occludin and Zonula Occluden-1 (ZO-1) expression levels were determined by immunohistochemical analysis and mRNA fluorescent quantitative PCR. Plasma levels of diamine oxidase (DAO) and d-lactate were determined using enzymatic spectrophotometry. Immunohistochemical results for occludin and ZO-1 showed disruption of the TJs in the intestinal mucosa in SUS-14 d and SUS-21 d groups. The expression levels of occludin and ZO-1 in SUS-21 d group were lower than those in SUS-14 d group, and significantly lower than those in CON group (Occldin: 0.86±0.02 vs 1.01±0.03 vs 1.63±0.03 and ZO-1: 0.82±0.01 vs 1.00±0.02 vs 1.55±0.01, P<0.01). Moreover, the levels of plasma DAO and d-lactate in SUS-21 d group were higher than those in SUS-14 d group, and significantly higher than those in CON group (DAO: 27.58±0.49 vs 20.74±0.49 vs 12.94±0.21 and d-lactate: 37.86±0.74 vs 28.26±1.01 vs 17.76±0.91, P<0.01). There were significant negative correlations between occludin or ZO-1 expression levels and DAO (r (2)=0.9014, r (2)=0.9355, P<0.01) or d-lactate levels (r (2)=0.8989, r (2)=0.9331, P<0.01). Occludin and Zo-1 were reduced in intestinal mucosa both in mRNA and protein levels in the rat tail-suspension model. The significant negative correlations between expression levels of TJs and plasma levels of DAO or d-lactate support the hypothesis that intestinal permeability is increased due to a decrease in TJ protein expression during tail-suspension from 14 days to 21 days.
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SOX17 antagonizes WNT/?-catenin signaling pathway in hepatocellular carcinoma.
Epigenetics
PUBLISHED: 11-22-2010
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SRY-box containing gene 17 (SOX17) was reported to be indispensable for embryonic development and a candidate tumor suppressor gene which antagonizes the canonical WNT/?-catenin signaling pathway in colorectal cancer. In this study, we investigated the function and epigenetic regulation of SOX17 in human hepatocellular carcinoma (HCC). DNA methylation of SOX17 was analyzed in 62 human HCC tissues and HCC cell lines by MSP. A role as a tumor suppressor gene was evaluated by colony formation assay and regulation of WNT/?-catenin signal pathway by SOX17 was determined by IHC and luciferase reporter assay. DNA methylation of the SOX17 promoter region occurs in 82% of HCC tissues and is associated with nuclear accumulation of ?-catenin. Restoration of SOX17 inhibits HepG2 colony formation and ?-catenin/TCF-dependent transcription with the presence of HMG box in SOX17. In conclusion, SOX17 negatively regulates canonical WNT/?-catenin signaling pathway and inhibits human HCC cells growth, providing an explanation for the loss of expression by epigenetic mechanisms in these tumors.
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CD137-mediated pathogenesis from chronic hepatitis to hepatocellular carcinoma in hepatitis B virus-transgenic mice.
J. Immunol.
PUBLISHED: 11-08-2010
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Chronic hepatitis B virus (HBV) infection is characterized by sustained liver inflammation with an influx of lymphocytes, which contributes to the development of cirrhosis and hepatocellular carcinoma. The mechanisms underlying this immune-mediated hepatic pathogenesis remain ill defined. We report in this article that repetitive infusion of anti-CD137 agonist mAb in HBV-transgenic mice closely mimics this process by sequentially inducing hepatitis, fibrosis, cirrhosis, and, ultimately, liver cancer. CD137 mAb initially triggers hepatic inflammatory infiltration due to activation of nonspecific CD8(+) T cells with memory phenotype. CD8(+) T cell-derived IFN-? plays a central role in the progression of chronic liver diseases by actively recruiting hepatic macrophages to produce fibrosis-promoting cytokines and chemokines, including TNF-?, IL-6, and MCP-1. Importantly, the natural ligand of CD137 was upregulated significantly in circulating CD14(+) monocytes in patients with chronic hepatitis B infection and closely correlated with development of liver cirrhosis. Thus, sustained CD137 stimulation may be a contributing factor for liver immunopathology in chronic HBV infection. Our studies reveal a common molecular pathway that is used to defend against viral infection but also causes chronic hepatic diseases.
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Progressive chromatin repression and promoter methylation of CTNNA1 associated with advanced myeloid malignancies.
Cancer Res.
PUBLISHED: 10-13-2009
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Complete loss or deletion of the long arm of chromosome 5 is frequent in myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML). The putative gene(s) deleted and responsible for the pathogenesis of these poor prognosis hematologic disorders remain controversial. This study is a comprehensive analysis of previously implicated and novel genes for epigenetic inactivation in AML and MDS. In 146 AML cases, methylation of CTNNA1 was frequent, and more common in AML patients with 5q deletion (31%) than those without 5q deletion (14%), whereas no methylation of other 5q genes was observed. In 31 MDS cases, CTNNA1 methylation was only found in high-risk MDS (>or=RAEB2), but not in low-risk MDS (
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DNA promoter hypermethylation of p16 and APC predicts neoplastic progression in Barretts esophagus.
Am. J. Gastroenterol.
PUBLISHED: 07-07-2009
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Prediction of progression to cancer in patients with Barretts esophagus (BE) is difficult using current techniques. We determined whether DNA promoter hypermethylation of genes frequently methylated in esophageal adenocarcinoma (p16 and APC) could be used as predictors of progression in BE.
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Long non-coding RNA gadd7 interacts with TDP-43 and regulates Cdk6 mRNA decay.
EMBO J.
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Long non-coding RNAs (lncRNAs) transcribed extensively from the genome have been proposed to be key regulators of diverse biological processes. However, little is known about the role of lncRNAs in regulation of the cell-cycle G1/S checkpoint following DNA damage, a key step in the maintenance of genomic fidelity. Here we show that growth-arrested DNA damage-inducible gene 7 (gadd7), a DNA damage-inducible lncRNA, regulates the G1/S checkpoint in response to UV irradiation. Interestingly, UV-induced gadd7 directly binds to TAR DNA-binding protein (TDP-43) and interferes with the interaction between TDP-43 and cyclin-dependent kinase 6 (Cdk6) mRNA, resulting in Cdk6 mRNA degradation. These findings demonstrate a role for gadd7 in controlling cell-cycle progression and define a novel mechanism by which lncRNAs modulate mRNA expression at the post-transcriptional level by altering mRNA stability.
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A facile and specific assay for quantifying microRNA by an optimized RT-qPCR approach.
PLoS ONE
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The spatiotemporal expression patterns of microRNAs (miRNAs) are important to the verification of their predicted function. RT-qPCR is the accepted technique for the quantification of miRNA expression; however, stem-loop RT-PCR and poly(T)-adapter assay, the two most frequently used methods, are not very convenient in practice and have poor specificity, respectively.
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Inhibition of SOX17 by microRNA 141 and methylation activates the WNT signaling pathway in esophageal cancer.
J Mol Diagn
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In this study, we explored the possibility of SOX17 promoter region methylation as an esophageal cancer detection marker, the regulation of SOX17 expression, and the function of SOX17 in the WNT signaling pathway in esophageal cancer. Eight esophageal cancer cell lines, 9 normal esophageal mucosa samples, 60 cases of dysplasia, and 169 cancer tissue samples were included. Methylation-specific PCR, semiquantitative reverse transcription-PCR, immunohistochemistry, luciferase reporter assay, colony formation, and Western blot analysis were used to analyze methylation and function of SOX17 in esophageal cancer. MicroRNA-related detection methods were performed to evaluate microRNA regulation of SOX17. SOX17 methylation was found in progression tendency with 0% of normal mucosa, 39% of grade 1 dysplasia, 48% of grades 2 and 3 dysplasia, and 65% of primary cancer. SOX17 methylation is related to esophageal cancer patients history of alcohol use and may induce ?-catenin expression and redistribution. Loss of SOX17 expression is correlated to promoter region hypermethylation, and re-expression was activated by 5-aza-2-deoxycytidine treatment in esophageal cancer cell lines. Restoration of SOX17 expression suppresses TCF/?-catenin-dependent transcription and colony formation. MicroRNA 141 was also found to down-regulate SOX17 expression and activate the WNT signal pathway. SOX17 is frequently methylated in esophageal cancer and in a progression tendency during esophageal carcinogenesis. Loss of SOX17 removes the normal inhibition of WNT signaling and promotes esophageal tumorigenesis.
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CDX2 serves as a Wnt signaling inhibitor and is frequently methylated in lung cancer.
Cancer Biol. Ther.
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Aberrant promoter region hypermethylation of upstream transcription factors may be responsible for silencing entire anti-neoplastic gene networks. In this study, we explored whether transcription factor coding gene, caudal-related homeobox 2 (CDX2), is silenced by promoter hypermethylation in lung cancer, and examined its potential tumor-suppressive functions. Semi-quantitative RT-PCR showed that four of six lung cancer cell lines exhibited no or weak CDX2 expression. Expression of CDX2 was correlated to CDX2 promoter region methylation status, as determined by methylation-specific PCR (MSP) and bisulfite sequencing. Restoration of CDX2 expression was induced by treatment with demethylating drug 5-aza-2-deoxycytidine (5-AZA) in lung cancer cell lines. Methylation of CDX2 was common in human primary lung cancer (61 of 110 tumors, 55.45%), but no methylation was found in normal lung tissues. Re-expression of CDX2 suppressed lung cancer cell proliferation and blocked cells in G1 phase. ?-catenin/TCF activity and downstream genes expression were inhibited by re-expression of CDX2, and increased by depletion of CDX2. In conclusion, CDX2 is frequently methylated in lung cancer, and expression of CDX2 is regulated by promoter region hypermethylation. CDX2 may serve as a tumor suppressor in lung cancer and inhibits lung cancer cell proliferation by suppressing Wnt signaling.
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SOX17 methylation inhibits its antagonism of Wnt signaling pathway in lung cancer.
Discov Med
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The purpose of this study was to explore epigenetic changes and functions of SOX17 in human lung cancer. Five lung cancer cell lines and 88 primary lung cancer samples were examined in this study. Methylation-specific polymerase chain reaction (MSP), semi-quantitative reverse-transcription PCR, immunohistochemistry, luciferase reporter assays, colony-formation assays, and western blotting were used to analyze methylation changes and functions of SOX17 in lung cancer. SOX17 methylation was found in 60.2% of primary human lung cancer samples, and promoter region methylation of SOX17 silenced its expression. SOX17 methylation was associated with female patients and lung cancer differentiation. Colony-formation assays revealed that SOX17 suppressed lung cancer cell proliferation. Re-expression of SOX17 inhibited Wnt signaling in H23 lung cancer cell line. SOX17 acts as a Wnt signaling inhibitor.
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Methylation of TFPI-2 is an early event of esophageal carcinogenesis.
Epigenomics
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To explore the epigenetic changes and the function of TFPI-2 in esophageal cancer.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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