Orai1 downregulation causes proliferation reduction and cell cycle arrest via inactivation of the Ras-NF-κB signaling pathway in osteoblasts

BACKGROUND: The purpose of this study was to determine the role of Orai1 in the regulation of the proliferation and cell cycle of osteoblasts. METHODS: The expression of Orai1 was inhibited by Orai1 small interfering RNA (siRNA) in MC3T3-E1 cells. Following Orai1 downregulation, cell proliferation and cell cycle were examined. Furthermore, the expression of cyclin D1, cyclin E, CDK4, and CDK6 was analyzed. The activity of the Ras-NF-κB signaling pathway was investigated to identify the role of Orai1 in the regulation of osteoblast proliferation. RESULTS: Orai1 was successfully downregulated in MC3T3-E1 cells by the Orai1 siRNA transfection (p < 0.05). We found that MC3T3-E1 cell proliferation was decreased, and the cell cycle was arrested by Orai1 downregulation (p < 0.05). Additionally, the expression of cyclin D1 was decreased by Orai1 downregulation (p < 0.05), as was the activity of the Ras-NF-κB signaling pathway (p < 0.05). Orai1 siRNA did not further reduce cell proliferation, the proportion of cells in the S phase, and cyclin D1 expression after chemical blockage of the Ras signaling pathway in MC3T3-E1 cells (p > 0.05). CONCLUSIONS: The results reveal that Orai1 downregulation may reduce cyclin D1 expression by inactivating the Ras-NF-κB signaling pathway thus blocking osteoblast proliferation and cell cycle. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12891-022-05311-y.