Expression of long non-coding RNA MALAT1 in osteosarcoma and its effect on invasiveness and metastatic potential of osteosarcoma cells

Abstract

To investigate the significance of long non-coding RNA MALAT1 expression in osteosarcoma, and the potential mechanism by which MALAT1 promotes tumor metastasis. Twenty cases of osteosarcoma in the First Affiliated Hospital of Xinxiang Medical University and Ping Ding Shan First People's Hospital were collected from January 2014 to December 2015. The expression of MALAT1 in osteosarcoma tissue and paired adjacent noncancerous tissue were analyzed by qRT-PCR. Correlation of MALAT1 expression in osteosarcoma with clinical pathologic features was performed by the Mann-Whitney U test. U-2OS cells were transfected with lenti-virus carrying MALAT1-shRNA and nonspecific shRNA (LV-vector). The expression of MALAT1 was detected by qRT-PCR. The cell activity was evaluated by MTT asssy. The impact of MALAT1-shRNA on invasion in U-2OS cells were determined by transwell migration assay. The expression of Wnt/β-catenin signal pathway related proteins were detected by Immunofluorescence stain and Western blot. The expression level of MALAT1 in osteosarcoma tissue was higher than that in paired adjacent noncancerous tissue and correlated significantly with nodal and pulmonary metastasis(P<0.01). MTT assay showed that knockdown of MALAT1 with lenti virus-MALAT1 shRNA inhibited the growth of U-2OS cells, along with marked decrease of invasive ability of U-2OS cells in the transwell migration assay. By immunofluorescence stain and Western blot assay, MALAT1 significantly reduced the expression of β-catenin, MMP7, and c-MYC in U-2OS cells. The expression of MALAT1 is high in osteosarcoma and correlates with tumor metastasis. MALAT1 promotes invasion and metastasis of osteosarcoma cells likely thought the Wnt/β-catenin signal pathway.