Abstract
BACKGROUND/AIMS: Colorectal cancer is the most common cancer in oncopathology, with an increasing incidence among the elderly during the last decade. Various genetic and environmental factors play important roles in the emergence of colorectal adenocarcinoma. Non-coding RNAs, approximately 20-22 nucleotides, are transcribed irregularly in many cancer cells and play a critical role in many metabolic pathways in clinical cancer cases. DNA methylation is a critical epigenetic alteration that controls gene expression. In the current study, transcriptional silencing and CpG hypermethylation were developed as a therapeutic gene editing strategy for the clinical repression of colorectal adenocarcinoma. METHODS: A human colorectal adenocarcinoma cell line (Caco2) and a normal lung fibroblast cell line (Wi38) were utilized as the paradigms in this research to examine the effect of mir155 molecule transfection and CpGs-island (CGI) methylation. Cell counting was achieved using six-well and 24-well plates before transfection using a hemocytometer. The two cell lines were transfected with the mir155 agomir and antagomir molecules. The transfection efficiency, cell viability, cell IC(50), and target gene expression were measured, and CGIs-methylation was achieved by bisulfate conversion. RESULTS: The outcomes revealed the downregulation of oncogenes (AKT1 and VCAM1 genes as cancer-associated genes) and the upregulation of tumor suppressor genes (TSGs, Tp53 and KEAP1). In addition, CpG-islands methylation showed significant blocking of the oncogene promoter regions, and the switch on of TSG promoter regions was continuous. CONCLUSIONS: miRNA-CGI-methylation led to the regression of Caco2 cell proliferation, suggesting the potential use of RNA silencing and DNA methylation in targeted gene therapy for colorectal cancer.