Abstract: Objective To investigate the regulation of lncRNA-ATB on the proliferation, aggregation, migration and apoptosis of S-phase cell cycle of osteosarcoma Saos-2 cells, and to explore its effect on the growth and cell proliferation of subcutaneous osteosarcoma. 
Methods Real-time quantity polymerase chain reaction (qRT-PCR) was used to detect the expression of lncRNA-ATB in osteosarcoma tissues, HOS, Saos-2 and U2OS cell lines and human osteoblast cell line NHOst. CCK8, flow cytometry, TUNEL and Transwell were used to detect the regulation of biological function of lncRNA-ATB in SAOS-2 cells. Ki67 was used to detect cell proliferation. The nude mouse xenograft model of osteosarcoma was constructed by using SAOS-2 cells, and the weight of subcutaneous tumor in nude mouse model was detected. 
Results In 28 patient tissues, the expression level of lncRNA-ATB in osteosarcoma tissue was higher than that in normal adjacent tissue (P＜0.05). Compared with the NHOst group, lncRNA-ATB was elevated in HOS, Saos-2, and U2OS, with the highest expression in Saos-2 (P＜0.05). The OD value of Saos-2 cells in the ATB group was higher than that in the NC group, and the S phase of the Saos-2 cycle in the ATB group was longer than that in the NC group (P＜0.05). The OD value of Saos-2 cells in the siATB group was lower than that in the siNC group, and the S phase of the Saos-2 cycle in the siATB group was shorter than that in the siNC group (P＜0.05). In the ATB group, the apoptosis rate of Saos-2 cells was inhibited, while in the siATB group, the apoptosis rate of Saos-2 cells was inceased. The number of cell perforations in the ATB group was higher than that in the NC group, which was lower in the siATB group than in the siNC group (P＜0.05). The weight of subcutaneous tumors was greater in the ATB group than in the NC group (P＜0.05), but smaller in the siATB group than in the siNC group (P＜0.05). The percentage of positive staining cells in the nucleus of osteosarcoma was higher in the ATB group than in the NC group, but lower in the siATB group than in the siNC group (P＜0.05). 
Conclusion LncRNA-ATB may promote the occurrence, development and malignant biological function of osteosarcoma, while RNA interference technology can inhibit the pathological process of osteosarcoma. 

Key words: osteosarcoma, lncRNA-ATB, siRNA, Saos-2