Abstract Cyclic AMP (cAMP) signaling plays a critical role in melanocyte proliferation and differentiation. However, the role of cAMP signaling in malignant transformation of human melanocytes and initiation of melanoma is not fully understood. Previously, we demonstrated that cAMP signaling plays opposite roles in primary and metastatic melanoma cells, i.e., pro- and anti-proliferative roles, respectively. This switch in cAMP action is mediated by the alternative cAMP signaling axis involving EPAC-RAP1 (exchange protein directly activated by cyclic AMP-Ras-related protein 1). In this study, we tested the hypothesis that activation of EPAC signaling is an early event in malignant transformation of melanocytes and is required for survival and proliferation of malignant melanocytes. Here, we show that shRNA-mediated knockdown of PTEN alone or PTEN-KD with lentiviral transduction with BRAF(V600E) results in upregulation of EPAC expression and activation of RAP1 (i.e., RAP1-GTP) in human primary melanocytes. Interestingly, activation of phosphoinositide 3-kinase (PI3K) signaling alone is sufficient for stimulation of maximal EPAC expression as well as proliferation suggesting that EPAC activation is an early event associated with loss of PTEN and melanoma tumor initiation. Inhibition of EPAC activity by either EPAC 1/2 or EPAC2-selective inhibitors suppressed the growth of transformed melanocytes by inhibiting cell cycle progression as evident by downregulation of cyclins E, -A2 and -B1. Inhibition of EPAC signaling also increased cells expressing senescence-associate beta galactosidase activity suggesting that EPAC may contribute to the senescence escape mechanisms in BRAF(V600E) melanocytes. Our data suggest that activation of PI3K pathway alone or in combination with mitogen-activated protein kinase pathway activates EPAC signaling in melanocytes. Since primary but not metastatic melanoma cells remain dependent on EPAC signaling, understanding the mechanisms of action EPAC can open new avenues to prevent melanomagenesis and inhibit melanoma tumor progression. Citation Format: Mithalesh Kumar Singh, Sarah Altameemi, Marcos Lares, Shreyans Sadangi, Vijayasaradhi Setaluri. Epac signaling facilitates malignant transformation of melanocytes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 112.