Upregulation of long-noncoding RNA PTPRG-AS1 can predict the poor prognosis and promote migration and invasion in patients with osteosarcoma

The present study aimed to determine the expression of the long non-coding RNA PTPRG-AS1 in patients with osteosarcoma, and to explore its role on the prognosis of patients and the process of osteosarcoma cell metastasis. Reverse transcription quantitative-PCR was performed to detect PTPRG-AS1 expression in osteosarcoma tumor tissues and cells (U2OS, SJSA1 and Saos-2), and normal tissues and cells (hFOB1.19). In addition, qPCR and western blotting were also used to detect mRNA and protein expression, respectively, whereas fluorescence in situ hybridization was used to locate the position of PTPRG-AS1 in osteosarcoma cells. Transwell assay was used to determine the migratory and invasive abilities of osteosarcoma cells. The results demonstrated that PTPRG-AS1 was highly expressed in osteosarcoma cells and tissues, which was compared with normal bone cells and adjacent healthy tissues. Furthermore, PTPRG-AS1 expression level in patients with osteosarcoma and lymph node metastasis or distal metastasis was elevated compared with normal tissues. In addition, the results from univariate and multivariate analyses demonstrated that PTPRG-AS1 expression level was significantly associated with Tumor-Node-Metastasis stage (P=0.025), lymph node metastasis (P=0.035) and distant metastasis (P=0.016) in patients with osteosarcoma. PTPRG-AS1 expression level (odd ratio, 3.012; 95% confidence interval, 1.564-4.219) was also considered as an independent risk factor affecting the 5-year survival rate of patients with osteosarcoma. Furthermore, the 5-year overall survival rate of patients with elevated PTPRG-AS1 expression level (56.36%) was significantly lower compared with patients with low PTPRG-AS1 expression level (78.43%). In addition, PTPRG-AS1 knockdown using small interfering RNA significantly decreased the invasive and migratory abilities of osteosarcoma cells in vitro. In summary, PTPRG-AS1 high expression in patients with osteosarcoma may predict the poor prognosis of patients, as PTPRG-AS may have a promoting effect on osteosarcoma cell metastasis.