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@# Objective:To investigate the role of FOXO3a in hypoxia-induced cisplatin (DDP) resistance in osteosarcoma cells. Methods: The FOXO3a expression was detected by RT-PCR and Western blotting in osteosarcoma U-2OS cell line under normoxia and hypoxia conditions. The effects of HIF-1α-siRNAand FOXO3a-siRNAon the expressions of HIF-1αand FOXO3a were detected by Western blotting. CCK-8 and Annexin V/PI assays were used to detect the function of FOXO3a in hypoxia-induced DDP resistance of U20S cells. Results: Hypoxia could significantly increase the mRNAand protein levels of FOXO3a in U-2OS cells (All P<0.05). The expression of FOXO3a was regulated by HIF-1α; compared with control group and HIF-1α-NC group, the FOX03a protein expression was significantly down-regulated in HIF-1α-siRNA group [(0.38±0.03) vs (0.89±0.08)， (0.91±0.07), all P<0.01]. Under hypoxia condition, FOXO3a-siRNA could decrease the tolerance of U-2OS cells to DDP [(38.50±2.83)% vs (61.75±5.73)%, P<0.01], and increase DDP-induced apoptosis of U-2OS cells [(73.41±6.13)% vs (32.38±2.23)%, (55.89±4.46)%,All P<0.05]. Conclusions: Hypoxia significantly enhanced DDP-resistance of U-2OS cells by increasing FOXO3a expression in a HIF-1-dependent manner.
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Objective:This study aimed to construct a lentiviral expression vector for microRNA-194 and investigate its effect on the metastasis of human osteosarcoma cell line U2-OS. Methods:Pri-and mature miR-194 amplified by PCR were inserted into the plenty-GFP vector and identified by restriction endonuclease digestion and nucleotide sequencing. The osteosarcoma cell line U2-OS was transfected with the lentivirus. Then, the stable transfected cells were used in Transwell and wound healing assay. Results:Restric-tion analysis and sequencing showed that the recombinant lentiviral expression vector was constructed correctly. The titers of obtained overexpression and suppression expression recombinant lentivirus were 1.5*108 and 4*108 TU/ml. Cell metastasis ability was signifi-cantly different in different experimental groups (P<0.01). Conclusion:The lentiviral expression vector for microRNA-194 was suc-cessfully constructed. MicroRNA-194 could influence the metastasis of the osteosarcoma cell line U2-OS;thus, it could be further ex-plored as a potential target in osteosarcoma therapy.
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Triptolide, a diterpene derived from Tripterygium wilfordii Hook f., a Chinese medicinal herb, has been reported to inhibit cell proliferation and induce apoptosis in various human cancer cells, but its anticancer effects on human osteosarcoma cells have not yet been elucidated. In this study, we investigated whether triptolide induces apoptosis in human osteosarcoma cells and the underlying molecular mechanisms. We firstly demonstrated that triptolide inhibited cell growth and induced apoptosis in U2OS cells. Western blot analysis showed that the levels of procaspase-8, -9, Bcl-2, Bid and mitochondrial cytochrome c were downregulated in triptolide-treated U2OS cells, whereas the levels of Fas, FasL, Bax, cytosolic cytochrome c, cleaved caspase-3 and cleaved PARP were upregulated. These results suggest that triptolide induces apoptosis in U2OS cells by activating both death receptor and mitochondrial apoptotic pathways.