sodium-bisulfite and Neoplasm-Metastasis

Tissue inhibitor of metalloproteinase-3 (TIMP-3) has an inhibitory effect on tumor development, growth and metastasis due to its interaction with matrix metalloproteinases (MMPs). We investigated the prognostic significance of TIMP-3 gene promoter methylation in esophageal squamous cell carcinoma (ESCC). TIMP-3 methylation was analyzed by MethyLight, a quantitative and methylation-specific PCR method. Hypermethylation was found in 9/51 (18%) surgically resected ESCC samples and was associated with reduced disease-free (p=0.0039) and overall survival (p=0.0047). Upon multivariate analysis, it was found to be an independent prognostic parameter for poor survival and was associated with earlier recurrence after surgery (p=0.0238), especially via pleural dissemination (p=0.001). Expression levels for TIMP-3 protein and for several MMPs were analyzed by Western blot analysis in 20 pairs of ESCC and adjacent normal tissue. The expression of MMP-2, -7 and -9 proteins in tumor tissue was significantly higher than in corresponding normal mucosa (p=0.0051, 0.0064 and 0.0004, respectively). In contrast, the expression of TIMP-3 protein in tumor tissue was significantly lower than in matched normal mucosa (p=0.0152). Tumors with TIMP-3 hypermethylation expressed lower levels of TIMP-3 protein compared to those without hypermethylation (p=0.0357). These results demonstrate that TIMP-3 hypermethylation is associated with lower TIMP-3 protein expression in ESCC and with poor patient survival due to a high frequency of recurrence by pleural dissemination.

Topics: Carcinoma, Squamous Cell; Disease-Free Survival; DNA Methylation; Esophageal Neoplasms; Gene Expression Regulation, Neoplastic; Humans; Mucous Membrane; Neoplasm Invasiveness; Neoplasm Metastasis; Polymerase Chain Reaction; Prognosis; Proportional Hazards Models; Sulfites; Tissue Inhibitor of Metalloproteinase-3; Treatment Outcome

Whereas synuclein gamma (SNCG) gene expression is usually highly tissue-specific and restricted to the nervous system, SNCG is expressed in advanced-stage breast and ovarian cancers. When overexpressed, SNCG stimulates cancer cell proliferation and metastasis. It is thought that the molecular mechanism of CpG island demethylation may underlie aberrant SNCG expression. To determine whether aberrant SNCG expression and demethylation play a role in gastric carcinogenesis, we examined the expression and methylation status of SNCG in primary gastric cancers, gastric cancer cell lines, and non-neoplastic gastric mucosal tissues.. Ten gastric cancer cell lines, 105 primary gastric cancers, and 10 non-neoplastic gastric mucosal tissues were examined. SNCG expression and methylation status were examined by reverse transcription-PCR and bisulfite-single-strand conformational polymorphism followed by direct sequencing, respectively. The relationship between SNCG methylation status and various clinicopathological factors of the primary gastric cancers was then analyzed.. SNCG mRNA expression was observed in 5 of 10 cell lines. Analysis of cell lines positive for SNCG expression revealed that most of the SNCG CpGs were demethylated. SNCG mRNA was not expressed in the 10 non-neoplastic gastric mucosal tissues, although several CpGs were demethylated. Of the 105 primary gastric cancers, 40 (38.1%) showed apparent SNCG demethylation, similar to the result obtained using cell lines. SNCG demethylation was more frequent in primary gastric cancers positive for lymph node metastasis (51%; 26 of 51) than in cancers without lymph node involvement (26%; 14 of 54; P < 0.05), and also more common in stage II-IV (48%; 27 of 56) than in stage I (27%; 13 of 49) cancers (P < 0.05).. Aberrant SNCG gene expression can occur via CpG island demethylation, and tends to occur during the more progressive stages of gastric carcinogenesis.

Topics: Adult; Aged; Aged, 80 and over; Azacitidine; Cell Division; Cell Line, Tumor; CpG Islands; Decitabine; Disease Progression; DNA Methylation; DNA, Complementary; Exons; Female; Gastric Mucosa; Gene Expression Regulation, Neoplastic; Humans; Male; Middle Aged; Neoplasm Metastasis; Nerve Tissue Proteins; Polymorphism, Single-Stranded Conformational; Prognosis; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stomach Neoplasms; Sulfites; Synucleins; Time Factors

Expression of the KAI1 gene, a metastasis-suppressor for prostate cancer, is reduced in all foci of prostatic metastasis. The altered regulatory mechanism is not strongly related to mutations or allelic losses of the KAI1 gene in prostate tumors. Since transcriptional silencing of genes has been found to be caused by epigenetic mechanisms, we have investigated the involvement of this epigenetic regulation of KAI1 expression in prostate cancers. The methylation status of the KAI1 promoter region was examined by restriction-enzyme digestion and sequencing, after amplifying a 331-bp fragment in the GC-rich promoter region from 4 human prostate cancer cell lines treated with bisulfite. The same 4 cell lines were also exposed to various concentrations of the demethylating agent, 5-aza-2'-deoxycytidine (5-AzaC) and / or the histone deacetylase inhibitor, trichostatin A (TSA). To clarify the influence of epigenetic modification on reduced KAI1 mRNA expression in the tumor cells, RT-PCR and northern-blot analyses were performed. Bisulfite-sequencing data showed a few methylated CpG islands in the promoter. RT-PCR analysis of 5-AzaC and / or TSA-treated cells indicated reversal of suppression of KAI1 transcription in two cell lines (PC-3 and DU-145), although the expression could not be detected by northern blots. From these results, it is suggested that epigenetic change is not the main mechanism of KAI1 down-regulation, though there remains a possibility that methylation in a more upstream region might be associated with this regulation.

Topics: Adenocarcinoma; Antigens, CD; Azacitidine; Base Sequence; Decitabine; DNA (Cytosine-5-)-Methyltransferases; DNA Methylation; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; Gene Silencing; Genes, Tumor Suppressor; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Kangai-1 Protein; Male; Membrane Glycoproteins; Molecular Sequence Data; Neoplasm Metastasis; Neoplasm Proteins; Polymerase Chain Reaction; Promoter Regions, Genetic; Prostatic Hyperplasia; Prostatic Neoplasms; Proto-Oncogene Proteins; Sulfites; Tumor Cells, Cultured