Evaluation of the expression levels of microRNA-199a-5p, and SMAC gene in tumoral and healthy colon specimens of patients and in colorectal cancer cell line under treatment of oxaliplatin and 5-FU

Abstract

Genetic and epigenetic changes are important factors in the incidence and progression of colorectal cancer (CRC). In this regard, microRNA-199a and genes involved in the process of mitochondrial-related apoptosis can play an important role. In the present study, changes in the expression levels of microRNA-199a-5p and SMAC gene in colon tumor samples and healthy adjacent tissue of patients with CRC as well as in CRC adenocarcinoma SW480 cell line were evaluated and the effect of 5-fluorouracil and oxaloplatin on their expression in the cell line was explored. Methods: A total of 47 tumor and healthy tissue samples were collected from the intestines of patients with CRC during surgery. After extraction of total RNA of the samples, gene expression and microRNA expression were measured by Real-time PCR and compared and analyzed between the two study groups. Results: The relative expression level of microRNA-199a in tumor tissues showed a decrease compared to healthy marginal tissues. Also, the expression of SMAC gene involved in mitochondrial-dependent apoptosis in tumor samples significantly decreased compared to healthy samples (p<0.05). Similar results were observed in CRC cancer cell line. On the other hand, although the administration of 5-fluorouracil and oxaloplatin had no effect on the expression level of microRNA-199a, it was able to significantly increase the expression of the target gene SMAC (p<0.001).