FIG. 9.

Effects of silencing USO-containing isoforms on neurite outgrowth and apoptosis in tumor cells. (A) Number of neurites per cell in SH-SY5Y cells treated with siRNA USO. The number of neurites was evaluated in three separate experiments performed on SH-SY5Y cells transfected with siRNA USO or siRNA negative control. Cells were seeded on polylysine-coated slides (20 μg/ml) and fixed 24 h after transfection with 2.5% glutaraldehyde. Values are reported as changes in the numbers of neurites per cell for the control, and each determination represents the average of three individual fields (P < 0.05). (B) Percentage of apoptotic cells in leukemia cell lines (1, RS; 2, REH; 3, 697) treated with the siRNA negative control (white bars) or with siRNA USO (gray bars). The percentage of apoptotic cells was measured by cytofluorimetric analysis using annexin V and propidium iodide (PI) staining. Data are means plus standard errors of the mean (error bars) of two different experiments. (Right) Representative examples of the flow cytometric density plot of the annexin V test relative to leukemia cell line 1 treated for 24 h with the siRNA negative control or the siRNA USO. Early apoptotic cells are in quadrant 4 (Q4) in the lower part of each plot on the right side (annexin V positive and PI negative). The percentage of apoptotic cells is indicated in Q4. Annexin V binding to the cell surface and surface membrane permeability to PI are shown on the x and y axes, respectively.