Increased serum levels of miR-214 in patients with PCa with bone metastasis may serve as a potential biomarker by targeting PTEN.

MicroRNAs (miRNAs/miRs) are identified to serve key functions in the progression of various tumors. miR-214 is aberrantly expressed in various types of cancer. In the present study, the function of miR-214 and its feasibility as a potential non-invasive biomarker for patients with prostate cancer (PCa) in a hyperplasia group and a control group were investigated. First, RNA was isolated from the serum of 75 patients with PCa with bone metastasis, 65 patients with PCa with no bone metastasis and 70 healthy controls. The level of miR-214 expression was significantly upregulated in the serum of the bone metastasis group compared with the healthy control and non-bone metastasis groups. Expression levels of alkaline phosphatase (ALP), bone sialoprotein (BSP), collagen type I pyridine crosslinking peptide (ICTP) were also evaluated. The results indicated that serum levels of BSP, ALP and ICTP were increased in the bone metastasis group compared with that in the non-bone metastasis group, hyperplasia group and the control group (P<0.05). The expression level of miR-214 is positively associated with poorly differentiated tumors in patients with PCa with a Gleason score >7 (P<0.05). Western blot analysis demonstrated that phosphatase and tensin homolog (PTEN) was a target gene of miR-214. Additionally, silencing of PTEN significantly increased the invasive ability of PC3 cells even when miR-214 expression was inhibited. In summary, serum miR-214 expression may serve as a potential novel non-invasive biomarker for PCa screening through targeting PTEN.