Cyclic AMP-Epac signaling pathway contributes to repression of PUMA transcription in melanoma cells.

The universal second messenger cAMP regulates numerous cellular processes. Although the cAMP-signaling pathway leads to induction of gene transcription, it remains unknown whether this pathway contributes toward suppression of transcription. Here, we show that blockade of cAMP signaling using MDL12330A led to an increase in PUMA transcript levels, but not p21 in melanoma cells. cAMP downstream component Epac activation was essential for suppression of PUMA transcription as an Epac agonist reversed the effects of MDL12330A. These results suggest that transcriptional repression is one of the functions of the cAMP-Epac signaling pathway.