Fig. 3

The effect of SgK223 overexpression on specific signaling pathways. a SgK223 does not affect activation of Erk or Akt. Western blots were undertaken as indicated. Phospho-Erk and -Akt (T308) signals were quantitated by densitometry and normalized for total expression, and expressed relative to the value for control cells, which was arbitrarily set at 1.0. The histograms represent the mean +/− the SE from three independent experiments. b SgK223 enhances Stat3 tyrosine phosphorylation (pY705). Data are normalized and expressed as in the previous panel. **indicates significance with a P-value < 0.005. c SgK223 enhances Stat3 transcriptional activity. Data are expressed relative to the value for control cells, which was arbitrarily set at 1.0. The histograms represent the mean +/− the SE from three independent experiments. ** indicates significance with a P-value < 0.005. d SgK223 knockdown in AsPC-1 PDAC cells decreases Stat3 activation. Two days following transfection using non-targeting (NT) or individual siRNAs directed against SgK223, cell lysates were prepared and Western blotted as indicated. e SgK223 and Stat3 associate in vivo. Control (−) or SgK223-overexpressing (+) HPDE cells were subject to immunoprecipitation (IP) using Stat3 antibodies, or corresponding mouse IgG (negative control). IPs or total cell lysates before IP were Western blotted as indicated. The upper and lower panel of the Stat3 blot represent a short and long exposure, respectively