LncRNA GAS5 Suppresses the Proliferation and Invasion of Osteosarcoma Cells via the miR-23a-3p/PTEN/PI3K/AKT Pathway

Accumulating evidence has shown that long noncoding RNA GAS5 is a well-known tumor suppressor in the pathogenesis of a variety of human cancers. However, the detailed role of GAS5 in osteosarcoma is still largely unclear. In this study, we found that GAS5 was downregulated in human osteosarcoma tissues and cell lines compared with matched adjacent tissues and normal osteoblast cells. Overexpression of GAS5 could significantly suppress the growth and invasion of osteosarcoma cells, while downregulation of GAS5 promoted cell proliferation and invasion. We confirmed that GAS5 could directly bind with miR-23a-3p by using luciferase reporter gene and RNA immunoprecipitation and pull-down assay. Downregulation of miR-23a-3p repressed cell proliferation and invasion. Overexpression of miR-23a-3p counterbalanced the inhibition effect of GAS5 on cell proliferation and invasion. Further studies indicated that overexpression of GAS5 inhibited cell proliferation and metastasis by regulating phosphatase and tensin homolog (PTEN). PTEN was authenticated as a target of miR-23a-3p. Upregulation of GAS5 or silence of miR-23a-3p increased the level of PTEN, while downregulation of GAS5 or overexpression of miR-23a-3p suppressed the expression of PTEN. In addition, overexpression of GAS5 could neutralize the effect of downregulating PTEN on osteosarcoma cell functions. We proved that GAS5 regulated the viability and invasion of osteosarcoma cells through the PI3K/AKT pathway. Moreover, overexpression of GAS5 could inhibit tumor growth in a xenograft nude mouse model in vivo. In summary, GAS5 functions as a competing endogenous RNA, sponging miR-23a-3p, to promote PTEN expression and suppress cell growth and invasion in osteosarcoma by regulating the PI3K/AKT pathway.

LncRNA GAS5 suppresses the tumorigenesis of cervical cancer by downregulating miR-196a and miR-205

Growth arrest special 5 (GAS5) is a long non-coding RNA reported to function as an inhibitor in various tumors including cervical cancer. However, the molecular mechanism of GAS5 involved in cervical cancer progression remains far from being elucidated. The expression of GAS5, forkhead box protein O1 and phosphatase and tensin homolog was examined by quantitative reverse transcription polymerase chain reaction qRT-PCR. cell growth, invasion, and apoptosis were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony formation assay, transwell invasion assay, and flow cytometry analysis, respectively. The interaction between GAS5 and miR-196a or miR-205 was confirmed by luciferase reporter assay, RNA immunoprecipitation assay, and qRT-PCR. Xenograft tumor experiments were performed to validate the biological role of GAS5 and its molecular mechanism in cervical cancer in vivo. GAS5 expression was decreased in cervical cancer tissues and cells. GAS5 overexpression suppressed cervical cancer cell proliferation, invasion, and apoptosis. GAS5 was able to directly bind to miR-196a and miR-205 to downregulate their expression. Moreover, GAS5 induced forkhead box protein O1 and phosphatase and tensin homolog expression by repressing miR-196a and miR-205, respectively. Exogenous expression of GAS5 hindered tumor growth in vivo by downregulating miR-196a and miR-205. Upregulation of GAS5 suppressed cell proliferation, invasion, and apoptosis of cervical cancer cells by downregulating miR-196a and miR-205, contributing to our understanding the pathogenesis of cervical cancer and development of long non-coding RNA-mediated clinical therapy against this disease.