Circular RNA VRK1 correlates with favourable prognosis, inhibits cell proliferation but promotes apoptosis in breast cancer.

ABSTRACT

OBJECTIVE: This study aimed to evaluate the correlation between the circular RNA VRK serine/threonine kinase 1 (circ-VRK1) and the clinicopathological features and survival outcomes of breast cancer patients and determine its effects on breast cancer cell proliferation and apoptosis. METHODS: A total of 350 breast cancer tissues and 163 breast cancer adjacent tissues, as controls, were acquired from Specimen House. Circ-VRK1 expression was measured using qPCR. The correlations between circ-VRK1 expression and demographic characteristics, tumour features and overall survival were analysed. In vitro, the effects of circ-VRK1 on breast cancer cell proliferation and apoptosis were measured by upregulating and downregulating circ-VRK1 expression via plasmid transfection. RESULTS: Circ-VRK1 was downregulated in breast cancer tissues compared with adjacent tissues and represented a good value in distinguishing breast cancer tissues from the adjacent tissues. Circ-VRK1 was associated with smaller tumour size, reduced T stage and lower TNM stage, and circ-VRK1 was also an independent predictor of better overall survival. According to the in vitro experiments, circ-VRK1 expression was lower in breast cancer cell lines (including BT474, MDA-MB-453 and MDA-MB-231) than in a normal breast epithelial cell line (MCF10A), and circ-VRK1 inhibited cell proliferation but promoted cell apoptosis in MDA-MB-231 cells. CONCLUSION: Circ-VRK1 is downregulated in tumour tissues and associated with reduced tumour stage as well as better survival, and it inhibits cell proliferation but promotes cell apoptosis in breast cancer.