Figure 5.

Activation of STAT3, induction of CIS3 protein, and the effect of forced expression of CIS3 on LIF-induced STAT3 activation and IL-1β production in a mouse colon cell line, CMT. (A, Western) Cells grown in six-well dishes were stimulated with 10 ng/ml LIF for indicated periods, and total cell extracts were then immunoblotted with anti–phospho-STAT3, anti-STAT3, and rabbit anti-CIS3 polyclonal antibodies. In B and C, CMT cells stably transformed with CIS3 (CMT-CIS3) were stimulated with 10 ng/ml LIF for indicated periods, and then STAT3 phosphorylation and IL-1β production were measured by immunoblotting (B, Western) and RT-PCR analysis (C, RT-PCR), respectively. Three independent CMT transformants were examined and similar results were obtained.