High expression of long non-coding RNA XIST in osteosarcoma is associated with cell proliferation and poor prognosis.

OBJECTIVE Osteosarcoma is one of the most common primary bone malignancies. Long non-coding RNAs (lncRNAs) have recently emerged as key regulators of osteosarcoma. The aim of present study was to explore the prognostic value of long non-coding RNA XIST (XIST) in osteosarcoma and XIST's relation to the cell proliferation in osteosarcoma in vitro. PATIENTS AND METHODS The XIST expressions were detected in osteosarcoma tissues and their paired adjacent normal tissues from 145 osteosarcoma patients by using qRT-PCR. The association between XIST expression and clinicopathological factors, as well as survival rates, was analyzed. The possibility of XIST as a prognostic biomarker for osteosarcoma was examined by Cox proportional hazard regression model. MTT assays were conducted to explore the impact of XIST overexpression on the proliferation of osteosarcoma cells. RESULTS The results showed that XIST was significantly up-regulated in osteosarcoma tissues and cell lines, and high XIST expression was significantly associated with advanced tumor size (p=0.009), advanced clinical stage (p=0.001) and present distant metastasis (p=0.009). Kaplan-Meier analysis showed that increased XIST expression was associated with poor overall survival of patients. Univariate and multivariate analysis suggested that XIST expression was an independent prognostic factor for the survival of patients with osteosarcoma. Furthermore, we found that knockdown of XIST significantly suppressed the proliferation of osteosarcoma cells in vitro. CONCLUSIONS XIST was suggested to have a tumor promoter effect, and thus, to be a predictor of outcome in patients with osteosarcoma.