Value of promoter methylation in colorectal cancer screening and prognosis assessment and its influence on the activity of cancer cells.

INTRODUCTION

The aim of the study was to investigate the effect of promoter methylation on the proliferative, invasive and migration potential of colorectal cancer cells, including its potential use for the early detection and prognostic assessment of colorectal cancer.

MATERIAL AND METHODS

Quantitative methylation-specific PCR (qMSP) was used to detect the methylation status of the promoter region in peripheral blood samples drawn from patients with colorectal adenocarcinoma, benign colorectal adenoma, and matched healthy controls. Putative CpG methylation sites were then pyrosequenced. We subsequently suppressed methylation within colon cancer cells via treatment with 5-azacytidine and overexpressed colon cancer cells by transfection with a -overexpression pcDNA3.0 plasmid. Thereafter, the methylation status and mRNA and protein expressions levels were determined. Finally, the proliferative, invasive and migration abilities of cell lines were determined with the CCK-8 and Transwell cell assays.

RESULTS

There were differences in the methylation status at loci 2216, 2226, 2231, 2245, and 2254 within the promoter region of between patients with colorectal adenocarcinoma, colorectal adenoma, and healthy volunteers. The methylation status of CpG sequence 2245 significantly correlated with tumor diameter, invasion depth, TNM stage, grade, and lymph node metastasis ( < 0.05). The proliferative, invasive and migration abilities of colon cancer cells treated with 5-azaC or transfected with a -overexpression plasmid were significantly impaired relative to negative controls ( < 0.05).

CONCLUSIONS

The methylation status at locus 2245 within the CNRIP1 promoter region has potential value for the early detection and prognostic evaluation of colorectal cancers. Demethylation of the promoter or overexpression of can reduce the proliferative and migration abilities of colon cancer cells.