Effects Of DDX49 Gene Inhibition On Growth Of Human Osteosarcoma Cells

BackgroundOsteosarcoma(OS)is the most common primary bone cancer.It is a high-grade malignancy with high risk for the development of distant metastases.Compared with other bone tumors,OS patients have worse prognoses.Unfortunately,few survival improvements have been achieved through the last 30 years.DEAD-box RNA helicases(DDX)are implicated in almost all of processes of RNA metabolism,transcription,translation and are associated with cellular proliferation and tumor transformation.Human DDX49 gene belongs to DDX family.Its expression pattern and biology roles in cancer cells have not been illustrated before.AimsThe aims of present study were to detect the effects of DDX49 gene inhibition on growth and apoptosis of human osteosarcoma cells,in order to develop novel diagnostic and potential therapeutic target.MethodsDDX49 gene expression in 4 OS cell lines was evaluated by Quantitative real-time polymerase chain reaction(qRT-PCR);DDX49 was inhibited by Lentivirus mediated RNA interference(RNAi)in U-2OS cells,then qRT-PCR was used to detect the knockdown efficiency of DDX49 gene expression,Cell growth were measured using Celigo Image Cytometer,cell viability was evaluated using the methylthiazoletetrazolium(MTT)assay and cell apoptosis was detected using flow cytometer.ResultsThe result of qRT-PCR showed that DDX49 gene was expressed in 4 OS cell lines;DDX49gene was efficiently knocked down in U-2OS cells by DDX49-RNAi-lentivirus on mRNA level after 3 days of infection,compared with non-silencing control lentivirus;After infection with lentivirus,U-2OS cells dynamic growth was continuously monitored under Celigo Image Cytometer for 5 days,the results showed that U-2OS cell proliferation was markedly inhibited by DDX49-RNAi-lentivirus,compared with non-silencing control lentivirus;After 3 days of infection with lentivirus,U-2OS cells was continuously detected for 5 days by MTT assay,the resultsshowed that the absorbance at 490 nm was gradually decreased in DDX49 silenced group,compared with non-silenced control group,indicating that inhibition of DDX49 gene expression can significantly reduce the cell viability of U-2OS cells;After 3 days of infection with lentivirus,the apoptosis of U-2OS cells was markedly increased in DDX49 silenced group,compared with DDX49 non-silenced control group,suggesting that DDX49 gene was significantly associated with U-2OS cell apoptosis.ConclusionThese results indicate that DDX49 is critical for human osteosarcoma U-2OS cells proliferation and maybe is a potential therapeutic target for osteosarcoma treatment.