Expression pattern of circadian rhythm-related genes and its potential relationship with miRNAs activity in endometrial cancer

Objectives: The circadian clock is an autonomous oscillator that controls key aspects of cell physiology, including metabolism, transcriptional state, and cell signaling. Disturbances of circadian rhythms lead to disruption of cell and tissue homeostasis, which promotes carcinogenesis. The aim of the study was to determine the expression of cir-cadian rhythm-related genes in endometrial cancer and to select miRNAs involved in the regulation of their expression.Material and methods: 50 endometrial tissue samples were collected from patients who underwent hysterectomy: 40 diagnosed with endometrial cancer and 10 without cancer. Expression profile of circadian rhythm-related genes was evaluated using microarrays and validated with RT-qPCR. MicroRNA expression was assessed using microarrays. Then mirTAR tool was used to identify miRNAs involved in the expression regulation of circadian rhythm-related genes.Results: CLOCKexpression is disrupted in endometrial cancer, which may be due to miR-15b, miR-331-3p and miR-200a overexpression. Elevated NPAS2 and CSNK1D levels may be associated with miR-432 silencing. In addition, high miR--874and miR-200a expression may be potentially responsible for the reduction of PER3 level.Conclusions: Change of CLOCK, CSNK1D, NPAS2 and PER3 expression may suggest that circadian rhythms are disrupted in endometrial cancer. A possible mechanism of the observed changes may be related to miRNAs activity.