FIGURE 6.
Regulation of Cyclin D1 expression by STAT3 signaling in SmoM2-mediated carcinogenesis. Expression of several putative STAT3 target genes in tumor-bearing epidermis was assessed by real-time PCR. These genes include cyclin D1 (A), BCL-XL (B), HSP70 (C), and Survivin (D). Following STAT3 ablation in epidermis, SmoM2-induced expression of cyclin D1 was examined at the protein level, which was detected by Western blotting (E). Please note that STAT3 ablation in epidermis did not completely wipe out all cyclin D1 expression. To rule out the possibility that the effect of STAT3 knockout was due to nonspecific regulation of Hh signaling, we detected Hh target gene expression from skin tissues of K14cre-Rosa26-SmoM2/STAT3+/+ mice or K14cre-Rosa26-SmoM2/STAT3flp/flp mice, with the K14 transcript as the internal control (supplemental Fig. 1), and found that Gli1 expression was not significantly altered by STAT3 depletion. *, p < 0.05.