Objective To investigate the effect of HIF-2a silencing by transfection of siRNA into MG-63 cells un-der hypoxia. Methods HIF-2αexpression level in MG-63 cells under hypoxia was determined by Western Blot. Small in-terfering RNA (siRNA) was used to construct MG-63/siHIF-2α(siHIF-2α)cells and control MG-63/scramble (NC) cells. The expression levels of HIF-2α, Vascular endothelial growth factor (VEGF), p-Erk/ErK and Mcl-1 in MG-63, NC and si-HIF-2αcells was determined by Western Blot. NC and siHIF-2αcells were cultured under hypoxia. Cell viability was as-sessed by MTT assay. Migration was identified by scratch migration assay. Tumor formation was identified by clone formation assay. Nude mouse subcutaneous xenograft model was used to investigate tumor development in vivo. Results Hypoxia im-proved HIF-2αexpression in MG-63 cells in a time-dependent manner (F=2 037.412,P<0.001). HIF-2αexpression un-der hypoxia in siHIF-2αcells was lower than that in NC cells (P<0.01). Cell viability of siHIF-2αcells under hypoxia for 12 h and 24 h were lower than that in NC cells (P<0.05 or P<0.01). The relative width of scratch in siHIF-2αgroup under hypoxia for 12 h and 24 h were larger than that in NC group (P<0.01 or P<0.01). When cell counts reach 1 000-5 000, the clone formation rates of siHIF-2αcells were lower than that in NC cells (P<0.05 or P<0.01). The expression of VEGF, p-Erk/Erk and Mcl-1 protein under hypoxia in siHIF-2αcells was lower than that in NC cells(P<0.01). Tumor sizes, weights and density of siHIF-2α group in nude mice were suppressed compared with those in NC group (P<0.01). Conclusion Blocking HIF-2αsignal pathway warrants its investigation as a potential strategy in osteosarcoma treatment.%目的：探讨低氧诱导因子-2α（HIF-2α）基因沉默对低氧状态下骨肉瘤MG-63细胞的影响。方法Western Blot检测MG-63细胞HIF-2α表达。利用小干扰RNA（siRNA）获得MG-63/siHIF-2α（siHIF-2α）细胞，阴性对照为MG-63/scramble(NC)细胞。Western Blot检测MG-63、NC和siHIF-2α细胞中HIF-2α、血管内皮生长因子（VEGF）、p-Erk/Erk及Mcl-1的表达。低氧下培养NC和siHIF-2α细胞，MTS试剂检测细胞活性，划痕迁移试验检测迁移能力，克隆集落形成试验检测集落形成率，裸鼠皮下移植瘤试验检测体内肿瘤生长情况。结果低氧可诱导MG-63细胞的HIF-2α蛋白表达，并呈时间依赖性(F=2037.412，P＜0.001)。低氧下siHIF-2α细胞的HIF-2α表达低于NC细胞（P＜0.01）。低氧12 h和24 h，siHIF-2α组细胞活性均低于NC组，相对划痕宽度均大于NC组（P＜0.05或P＜0.01）。1000~5000细胞种植数的siHIF-2α组的集落形成率均小于NC组(P＜0.05或P＜0.01)。低氧下siHIF-2α细胞的VEGF、p-Erk/Erk和Mcl-1表达均低于NC细胞（P＜0.01）。裸鼠皮下移植瘤siHIF-2α组肿瘤体积、质量和密度均小于NC组(P＜0.01)。结论阻断HIF-2α信号通路可作为骨肉瘤临床治疗的新策略。
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