Fig. 8. Inhibition of Stat3-mediated cell proliferation by GRIM-19. (A) v-Src-transformed NIH-3T3 cells were grown in a 96-well micro titer plate and transfected with two doses of GRIM-19 (low, 0.1 µg; or high, 0.3 µg) or empty vector (–, 0.3 µg) (left panel), or treated with various concentrations of IFN-β and RA for 48 h (right panel). The cell proliferation assay was performed using the Cell Proliferation Kit II (XTT). Spectrophotometric absorbance was measured at 485 nm wavelength, and reference wavelength 650 nm, which presents a mean of three samples, with the standard deviation given as the error bars. (B) NIH-3T3 cells with stable expression of ST3-ΔN (bar with grid) or control vector (empty bar) were transfected with control vector (–) or with 0.1 µg of GRIM-19 (+), and cell proliferation was measured as described in (A).