Fig. 2

Expression and phosphorylation of Stat3 in SKN-SH wild-type (W) and SKN-SH/Dox6 drug-resistant (R) human neuroblastoma cells. (A) Western blot of Stat3, phospho-Stat3, and NF-kappa B in the cytoplasm and nucleus of W and R cells. Cytoplasmic and nuclear fractions were prepared as described in “Methods.” Proteins were electrophoresed on SDS-PAGE and probed with specific antibodies to Stat3, phospho-Stat3, and NF-Kappa B. (B) Densitometric analysis of Phospho-Stat3 expression in the cytoplasm and nuclei of W and R cells (Sigma Gel Program). Data represent the mean 6 SEM of three independent experiments expressed in arbitrary units (AU).