MicroRNA‑222‑3p promotes tumor cell migration and invasion and inhibits apoptosis, and is correlated with an unfavorable prognosis of patients with renal cell carcinoma

The aim of the present study was to investigate the role of microRNA (miR)-222-3p in renal cell carcinoma (Rcc). The expression level of miR-222-3p was detected in Rcc tissues and cell lines (AcHN, 786-O, caki-1 and 769-P) and was identified to be significantly upregulated compared with the level in adjacent normal renal tissues and HK-2 cells. Further in vitro experiments demonstrated that the overexpression of miR-222-3p promoted the migration and invasion, and attenuated the apoptosis of 786-O cells, whereas the knockdown of miR-222-3p suppressed the migration and invasion and induced the apoptosis of 786-O cells. Similar results were observed in the ACHN cell line in terms of migration, invasion and apoptosis. Furthermore, the expression level of miR‑222‑3p was measured in 42 RCC formaldehyde‑fixed paraffin‑embedded samples, and the association between the expression of miR-222-3p and the pathological characteristics and overall survival rate of patients with Rcc was analyzed. The results demonstrated that patients with a higher expression of miR‑222‑3p had a significantly lower overall survival rate, compared with those with a lower expression of miR-222-3p [hazard ratio (HR)=5.120; P=0.036]. Multivariate analysis identified that patients with a higher expression of miR-222-3p retained the statistically significant decrease in overall survival rate compared with patients with a lower expression of miR-222-3p (HR=5.636; P=0.030). Furthermore, Kaplan-Meier survival curves indicated that patients with higher miR‑222‑3p had significantly lower overall survival rates compared with patients with lower miR-222-3p (P=0.020). Taken together, these results suggested that miR-222-3p serves as an onco‑miR in RCC and may be a potential prognostic biomarker and therapeutic target in patients with RCC.