A novel mutation detection approach of hMLH1 and hMSH2 genes for screening of colorectal cancer.

Background: Recently, Denaturing High-Performance Liquid Chromatography (DHPLC) has been widely used for mutation detection hMLH1 and hMSH2 genes due to reduced cost of analysis, accuracy, and high sample throughput. Unfortunately, one major drawback in screening the hMLH1 and hMSH2 genes with any analysis technique involves sample preparation. Additionally, there are limitations to this technique which include: (1) amplicons for hMLH1 and hMSH2 exons cannot be generated under the same PCR thermal cycler condition due to differences in the annealing temperatures of the traditional primer sets which drastically increases sample preparation time; (2) due to minimal changes in the DHPLC chromatogram when compared to the corresponding wild-type amplicon, there is a possibility to not detect a homozygous mutation; and (3) lack of specialized mutation analysis software for automated screening of the hMLH1 and hMSH2 genes with the Transgenomic Wave system.

Modulation of CDK2-AP1 (p12(DOC-1)) expression in human colorectal cancer.

We have previously demonstrated an association between microsatellite instability and decreased CDK2-AP1 (p12(DOC-1)) expression in human colorectal cancer (CRC) cell lines. In those same studies, induction of CDK2-AP1 expression promoted both cell cycle arrest and apoptosis. The goals of our present study were to better understand the mechanisms leading to reduced CDK2-AP1 expression in microsatellite unstable (MSI) CRC and to study further the effect of CDK2-AP1 modulation on cell proliferation and apoptosis utilizing RNA interference (RNAi) techniques.

Deleted in oral cancer-1 expression upregulates proapoptosis elements in microsatellite-unstable human colorectal cancer.

Background: We previously reported differential expression of the growth suppressor, deleted in oral cancer-1 (DOC-1), in microsatellite-unstable (MSI+) versus microsatellite-stable colorectal cancer (CRC) cell lines. MSI+ CRC cell lines demonstrated decreased DOC-1 expression and decreased apoptosis. Transfection of wild-type DOC-1 into an MSI+ cell line (SW48) resulted in increased apoptosis.

Differential expression of DOC-1 in microsatellite-unstable human colorectal cancer.

The precise genetic mechanism of malignant transformation in DNA mismatch repair deficient, microsatellite-unstable colorectal cancer (CRC) has yet to be elucidated. We employed cDNA microarray to identify patterns of gene expression among CRC cell lines and to compare directly lines with and without microsatellite instability. This study was undertaken to test the hypothesis that microsatellite-unstable CRC cell lines demonstrate specific patterns of gene expression that differ significantly from those observed among microsatellite-stable CRC.