Expression and significance of Annexin A3 in the osteosarcoma cell lines HOS and U2OS.

Abstract

Annexin A3 (ANXA3) is highly expressed in different types of cancers, but the impact of ANXA3 in bone tumors is still not clear. In the present study, the expression of ANXA3 in osteosarcoma cells was first confirmed by cellular immunofluorescence. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis were used to detect the expression of ANXA3 in osteoblasts in the osteosarcoma cell lines U2OS and HOS. Furthermore, small interfering (si)-RNA were transfected into U2OS and HOS cells via a liposome-mediated method. Then once ANXA3 had been successfully downregulated in U2OS and HOS cells, the cells were collected and total protein was extracted after 48 h of transfection. Western blot analysis was used to confirm successful ANXA3 transfection into osteosarcoma cells and the apoptotic rate of HOS and U2OS was detected by flow cytometry. The expression of ANXA3 in the osteosarcoma cell lines HOS and U2OS were first observed by confocal laser scanning microscopy, and was then detected by RT-qPCR and western blotting. The mRNA and protein levels of ANXA3 in the osteosarcoma cell lines HOS and U2OS were significantly increased compared with osteoblasts, particularly in HOS cells. When siRNA was transfected into HOS and U2OS cells, the protein expression level of ANXA3 was measured via western blotting. The results indicated that the expression of ANXA3 was significantly decreased. In addition, to determine whether ANXA3 knockdown induced cell apoptosis, the present study analyzed the apoptotic rate by flow cytometry. The results revealed that ANXA3 knockdown markedly increased HOS and U2OS cell apoptosis. To the best of our knowledge, the present study is the first to confirm that ANXA3 is highly expressed in the osteosarcoma cell lines HOS and U2OS. In addition, downregulation of ANXA3 expression in HOS and U2OS cells could increase apoptotic ability.