Differential expression of miRNAs related to autophagy pathway in tissue and serum samples of colorectal cancer patients.

ABSTRACT

BACKGROUND: This study was aimed to investigate the relationship of miR-17-5p, miR-30b, miR-30d, miR-216a and miR-216b associated with autophagy gene beclin 1, and beclin 1 gene with colorectal cancer (CRC). MATERIALS AND METHODS: Forty-seven patients with CRC and 50 healthy individuals with no cancer history were included in this study. In the serum, tumor and non-tumoral tissue samples of the CRC patients, and in the serum samples of the healthy subjects, expression levels of miRNAs were detected by qRT-PCR. The beclin 1 gene expression levels were determined by qRT-PCR, and protein levels were determined by Western blot method in tumor and non-tumor tissue samples of the patients. RESULTS: The miR-17-5p and miR-30d expressions were found to be higher in tumor tissue as compared to patient non-tumor tissues, while expressions of beclin-1, miR-30b and miR-216a were found to be lower. In addition, the beclin-1 protein levels were significantly decreased in the tumor tissue as compared to those in the patient non-tumor tissues. The miR-30d expression was significantly reduced in the serum of the patients when the serum samples of CRC patients and healthy controls were compared. CONCLUSION: The beclin 1 gene may play a role as a tumor suppressor in CRC. Moreover, these miRNAs cannot be used as highly reliable biomarkers in serum for CRC diagnosis (Tab. 2, Fig. 6, Ref. 46).