Fig. 3

Inhibition of miR-224 suppresses the cell proliferation, tumor growth, cell migration and invasion induced by hypoxia in gastric cancer cells. a MTT assay: SGC-7901 and MGC-803 cells were transfected with miR-224 mimics under normoxia or miR-224 ASO under hypoxia, together with controls. Cell viability was measured by MTT assay at 24, 48 and 72 h after transfection. b Colony formation assay: the transfected cells as (a) were seeded in 12-well plates and medium was changed every 3 days until most colonies contained more than 50 cells. The pictures showed the colonies stained by crystal violet. c SGC-7901 cells transfected with miR-224 antagomir or controls were injected subcutaneously into the flanks of 6 young athymic nude mice, and tumor volumes were measured every 5 days until day 25 when the mice were sacrificed. The pictures showed the xenografts when the mice were sacrificed. d In vitro scratch assay (cell migration assay): When the confluence of the transfected cells reached approximately 80%, a scratch was generated with a 200 μl tip and the cells were incubated with 1% FBS-containing medium. The wound was taken pictures at different time points. e Cell invasion assay: The transfected cells were (2.5 × 104 cells) seeded in serum-free medium in a Matrigel-coated chamber, while the lower chamber was incubated with 10%-FBS containing medium. The cells were invaded for 20 h under hypoxia or normoxia. Non-invading cells were scraped with a cotton tips and invading cells were fixed and stained with crystal violet, followed by counted. *P < 0.05, **P < 0.01