MiRNA-34a inhibits human osteosarcoma proliferation by regulating the expression of ether-à-go-go 1 gene: a study in vitro / 肿瘤研究与临床

ABSTRACT

Objective To detect the influence of miRNA-34a (miR-34a) on the proliferation of osteosarcoma and the mechanisms responsible for miR-34a regulation.Methods The osteoblastic cell line MG-63 and Saos-2,human osteoblastic cell line hFOB 1.19,10 osteosarcoma tissues and 10 normal bone tissues were selected.The expression of miRNA-34a in osteosarcoma cells and tissues was detected by quantitative real-time polymerase chain reaction (qPCR).Next,a eukaryotic expression vector named pcDNA/miR-34a was constructed.Then,osteosarcoma cells were transfected with this eukaryotic expression vector and the effects of miR-34a overexpression on the proliferation and growth of osteosarcoma were measured using CCK-8,colony formation and xenograft model of nude mice.Finally,Western blot analysis was used to detect the expression of ether-à-go-go 1 (Eag1) gene in osteosarcoma cells after transfected with pcDNA/miR-34a or a miR-34a inhibitor miR-34a-2'-O-Methyl antisense oligoribonucleotide (miR-34a-2'-O-Me).Results Compared with normal bone tissues and osteoblastic cell line,miR-34a was down-regulated in osteosarcoma cell lines and tissues.Compared with the blank group and the control group,the cell survival rates of miR-34a group of the two cell lines were significantly lower [MG-63 72 hblank group (40.05±4.82) ％,control group (36.88± 4.66) ％,miRNA-34a group (26.24±6.22) ％;MG-63 96 hblank group (83.55±5.95) ％,control group (80.13± 4.48) ％,miRNA-34a group (30.21±7.26) ％;Saos-2 72 hblank group (46.45±8.15) ％,control group (43.33± 6.89) ％,miRNA-34a group (26.81±3.17) ％;Saos-2 96 hblank group (84.79±4.10) ％,control group (80.14± 3.11) ％,miRNA-34a group (31.77±5.17) ％].The similar results were obtained from colony formation assay (MG-63blank group 83.40±3.29,control group 80.00±3.06,miR-34a group 24.40±2.71;Saos-2blank group 85.00±3.32,control group 80.60±3.29,miR-34a group 30.40±4.94).The tumor volumes of osteosarcoma xenograft in the miR-34a group was significantly smaller than that in the blank group and control group after 21 days treatment (all P ＜ 0.001).Overexpression of miR-34a could decrease Eag1 expression in osteosarcoma cell lines while inhibition of miR-34a induced the of expression Eag1 (P ＜ 0.001).Conclusion MiR-34a plays a tumor suppressor role in osteosarcoma and could suppress the proliferation and growth of osteosarcoma through the regulation of Eag1.Moreover,it may be a novel target for osteosarcoma therapy.