RETRACTED: Long non-coding RNA AK093407 promotes proliferation and inhibits apoptosis of human osteosarcoma cells via STAT3 activation (Retracted Article)

Osteosarcoma is a malignant tumor of the skeletal system. Long non-coding RNAs (lncRNAs) have been shown to play significant role in osteosarcoma. The present study evaluated the effects and mechanism of lncRNA AK093407 in osteosarcoma. The study included human osteosarcoma cell line, U-2OS. Cell proliferation, viability, and apoptosis were measured using Ki-67 proliferation assay, MTT assay, and Annexin V/PI staining assay, respectively. Relative mRNA and protein expressions were measured using qRT-PCR and western blot, respectively. Interaction between AK093407 and STAT3 was identified using mass spectrometry and RNA pull-down assay. Results revealed that AK093407 was highly expressed in osteosarcoma cells and tissues. Then we demonstrated that overexpression of AK093407 promoted cell proliferation and viability and inhibited apoptosis, whereas suppression of AK093407 showed opposite effects. In addition, AK093407 regulated the expression of genes and proteins (Bcl-2, TGF-beta, NF-kappa B, and PCNA) involved in the cell proliferation, viability, and apoptosis. Furthermore, we showed that AK093407 interacted with STAT3, and promoted its phosphorylation. Lastly, we showed that STAT3 activation was essential for the effects of AK093407 on cell proliferation and apoptosis as the overexpression of AK093407 in the presence of STAT3 inhibitor did not promote cell proliferation and inhibit cell apoptosis. AK093407 is highly expressed in osteosarcoma cells and tissues, and promotes cell proliferation and viability and inhibits apoptosis of osteosarcoma cell line U-2OS via STAT3 activation.