The long-term objective of this proposal is to develop mechanism-based combination approaches that can either prevent the progression of primary cutaneous melanoma to metastatic disease and/or cause regression of metastatic melanoma. Primary cutaneous melanoma is treatable. The metastatic form is fatal with a 10-year survival rate of less than 5% in people who have stage IV disease. We have identified eugenol as a potent inhibitor of melanoma tumors. Published data from our laboratory also shows that eugenol prevents the metastasis of tumors in B16 xenografts. In this proposal we want to examine the role of the transcription factor E2F2 which we have found to be downregulated by eugenol in its growth inhibitory activity. We hypothesize that overexpression of E2F2 deregulates cell cycle control in melanoma cells and that downregulation of E2F2 is essential for eugenol-induced cell cycle block and apoptosis induction independent of DNA damage-signaling pathways.
Our specific aim to test this hypothesis is: to identify the role of E2F2 in deregulating cell cycle progression in melanoma cells and its involvement in eugenol induced growth inhibitory effects. Specifically we will determine (i) if the inhibition of E2F2 can prevent the continuous cycling of melanoma cells (ii) if E2F2 is a key player in eugenol-induced S-phase block and apoptosis induction and (iii) if the signal for eugenol-induced E2F2 downregulation is dependent upon DNA damage signaling. This pilot proposal will define the role of E2F2 in eugenol-induced growth inhibition, apoptosis induction and cell cycle block during the progression of melanoma cells, and identify the influence of E2F2 on the continuous cycling of melanoma cells. We will also determine how targeting E2F2 can affect functions of other E2F family members such as compensating for the absence of E2F2 as well as identify whether eugenol directly downregulates E2F2 or whether the effect is mediated via DNA damage. It is clear that multiple pathways are deregulated in cancer, it is only logical that a combination of various agents (chemical and or biological) that target different pathways be used to attack cancer cells. In this effort it is of utmost importance that the mechanism(s) of action of individual compounds be understood so that a rational combination of agents may be developed. This proposal addresses this very core of cancer chemoprevention that aims to reduce the national burden of high cost of treatment and loss of productive life.
