Fig. 3

Effects of stable overexpression of miR-96 and miR-183 in C666-1. a C666-1 cells stably expressing miR-96 and miR-183 were established by lentiviral transfection. Left panel: Transfection efficiency of the transfected cells expressing green fluorescence protein (GFP) was determined under microscopy. Representative photos show that over 90 % of the cells are visualized in green. Right panel: The expression of miR-96 or miR-186 in the stably transfected cells was confirmed by qRT-PCR. Histograms confirmed elevated expressions of miR-96 and miR-183 in the respective cells stably transfected with miR-96 and miR-183 (n = 3, all *P < 0.05). The effects of miR-96 and miR-183 overexpression in NPC cells were assessed by their (b) colony-forming and (c) sphere-forming capacities. b The histogram shows the number of colonies formed in the C666-1 cells expressing miR-96 or miR-183 compared to that of the vector control. The colony number of C666-1 cells expressing miR-183 is obviously lower than that of the control (n = 3, P = 0.18). However, no aberration was observed in colony formation between cells stably transfected with miR-96 and those with the vector. Representative photos of the colonies are shown in the right panel. c Both the number and size of the tumor spheres were reduced in the C666-1 cells expressing miR-96 and miR-183. The number of tumor spheres in the C666-1 cells stably expressing miR-96 and miR-183 and the vector control is illustrated in the histogram according to the sizes of the tumor spheres formed (<50 μm, 50–100 μm, > 100 μm) (mean data from 6 wells of a 6-well plate per group). C666-1 cells stably expressing miR-96 and miR-183 failed to form tumor spheres of diameter larger than 100 μm. Representative photos of the tumor spheres are shown in the right panel (magnification × 100). Lower panel: Representative photomicrographs reveal the difference in size of the spheres between each treatment group