Reversed growth characteristics by H-RasV12 and RHO GEF16 over-expression in SOD3 transfected cells.

(a,b) The 8505c SOD3 cells were stable transfected with H-RasV12 oncogene and analyzed by growth curve and 3-D invasion analysis. Both analysis suggested marked increase in the growth of SOD3 cells after H-RasV12 transfection. (c) The 8505c SOD3 cells were stably transfected with RHO GEF16. The real time RT-PCR suggested significant (p<0.01) increase in RHO GEF16 mRNA production that was confirmed by Western blotting (lower panel). (d,e) The BrdU DNA incorporation analysis showed significantly (p<0.001) increased nuclear proliferation after RHO GEF16 over-expression as compared to 8505c SOD3 cells. (f) The RNAi of RGS4 in 8505c SOD3 cells showed significant downregulation of RGS4 mRNA production. (g,h) However, the BrdU DNA incorporation analysis failed to show differences between 8505c control and 8505c SOD3/siRGS4 cells. (i) A schematic drawing hypothesizing the SOD3 action in the cells. SOD3 over-expression activates cell membrane RTKs and membrane associated non-receptor tyrosine kinases. Depending on the expression level of SOD3 the proliferative and migratory signal is either halted or promoted at the level of small GTPase regulatory genes and small GTPases.