[5-aza-2'-deoxycytidine-induced inhibition of CDH13 expression and its inhibitory effect on methylation status in human colon cancer cells in vitro and on growth of xenograft in nude mice].

Objective: To determine the inhibitory effect of 5-aza-2'-deoxycytidine (5-Aza-CdR) on the growth of human colon carcinoma cells and xenografts in nude mice, to observe its effect on CDH13 gene expression and methylation in the xenografts, and to explore the possible mechanisms.

Methods: Human colon carcinoma cell line HCT116 cells were treated with 5-Aza-CdR, and the cell morphology was observe by phase contrast microscopy. The cell growth was assessed by MTT assay.

Correlation between T-cadherin gene expression and aberrant methylation of T-cadherin promoter in human colon carcinoma cells.

Previous researches showed T-cadherin (CDH13) expression was downregulated in colon cancer tissues and was associated with increase of invasive and metastatic potential. This research was to observe the mechanisms responsible for inactivation of T-cadherin gene in colon carcinoma; we investigated the methylation status around the 5' promoter region of T-cadherin gene of Hct116 colon cancer cell line by methylation-specific polymerase chain reaction (MSP), also detected the expression change of T-cadherin mRNA and protein in Hct116 cell line after 5-Aza-CdR treatment by reverse transcriptase polymerase chain reaction and Western blotting, and compared the T-cadherin methylation status with T-cadherin mRNA and protein expression. We found that hypermethylation of T-cadherin was involved in Hct116 cell line, while T-cadherin mRNA and protein expression was almost lost or downregulated in Hct116 cell line.

[Effect of 5-Aza-CdR on expression and methylation of E-cadherin gene in human colon carcinoma cells].

Background And Objective: Colon cancer is one of the most common malignant tumors, and its pathogenesis is not fully understood. Transcriptional silencing by DNA methylation is believed to be an important mechanism of carcinogenesis. E-cadherin can suppress tumor cell invasion and metastasis, and is considered as an invasion/metastasis suppressor gene.