BACKGROUND: Osteosarcoma is a common malignant tumor of musculoskeletal stromal cells. Osteosarcoma clinical behavior depends mostly on the histologic grade, the site of primary tumor, the response to chemotherapy, and the presence of pulmonary metastases. The aim of this study was to knockout SHOX CNE9/10 in U2OS osteosarcoma cells and to analyze the effects on cell growth and apoptosis.

MATERIAL AND METHODS: U2OS cells with CNE9 knockout and U2OS cells with CNE10 knockout were established via the CRISPR/Cas9 system. Sanger sequencing was used to detect the success of the knockdown experiment. Western blotting and quantitative polymerase chain reaction were used to detect the expression levels of short stature homeobox-containing gene (SHOX) protein and messenger RNA (mRNA) after knockdown of CNE9 and CNE10. The cell viability and apoptotic rate were detected by the Cell Counting Kit-8 method and by flow cytometry.

RESULTS: The Sanger sequencing results showed that the knockdown experiment was successful. The levels of SHOX mRNA and protein were significantly reduced after knocking down CNE9 and CNE10. Knockdown of CNE9 and CNE10 significantly increased the growth and inhibited the apoptosis of U2OS osteosarcoma cells. CNE9/CNE10 knockdown U2OS cells were successfully constructed.

CONCLUSIONS: Knockdown of CNE9 and CNE10 promoted U2OS cell growth and inhibited apoptosis by decreasing SHOX expression. This CNE9/CNE10 knockout U2OS cell model could provide a bridge for the research on SHOX and CNEs in osteosarcoma.

Keywords: Cell Growth Processes, Osteosarcoma, Base Sequence, Bone Neoplasms, DNA, Intergenic, Gene Knockout Techniques, Short Stature Homeobox Protein