Evaluation of the role of timeless circadian gene in gastric cancer promotion

Abstract

Timeless is a circadian gene involved in diverse cell functions such as circadian genes regulation and cell division. Dysregulation of this gene is associated with different diseases including cancer. To the best of our knowledge, the role of the timeless gene in gastric cancer has been not evaluated. Therefore, this study aimd to evaluate the timeless gene expression in gastric cancer biopsies as well as its role in the pathogenesis of gastric cancer. Materials and Methods. Total RNA were extracted from 45 gastric cancer biopsy specimens and 40 specimen that were negative for cancer. Then mRNA expression was quantified by qRT-PCR. In addition, a loss of function analysis of timeless gene using gene-targeting siRNA oligos was performed to evaluate the effect of this gene on gastric adenocarcinoma cell line (AGS). MTT assay and cell cycle analysis were used to evaluate the proliferation and apoptosis of the transfected and control cells. A wound-healing assay was used to study the migration of cancer cells after timeless gene targeting. Finally, apoptosis rate of the studied cells was assesd. Results. High levels of timeless mRNA were detected in gastric cancer biopsies compared with tumor negative samples. However, the difference was not statistically significant (p>0.05). The down-re-regulation of timeless gene in AGS cells decreased the rate of proliferation and invasion of malignant cells and resulted in increased apoptosis in these cells significantly (p< 0.01).