Meeting report: consensus from the first and second Global Workshops in Melanoma November 19-20, 2008

Driver mutations in melanoma: lessons learned from bench-to-bedside studies

The identification of somatic driver mutations in human samples has allowed for the development of a molecular classification for melanoma. Recent breakthroughs in the treatment of metastatic melanoma have arisen as a result of these significant new insights into the molecular biology of the disease, particularly the development of inhibitors of activating BRAF(V600E) mutations. In this article the roles of several mutations known to be involved in the malignant transformation of melanocytes are reviewed including BRAF, PTEN, NRAS, ckit, and p16 as well as some of the emerging mutations in cutaneous and uveal melanoma. The bench to bedside collaborations that resulted in these discoveries are summarized, and potential therapeutic strategies to target driver mutations in specific patient subsets are discussed.

Evaluation of new iodinated acridine derivatives for targeted radionuclide therapy of melanoma using 125I, an Auger electron emitter

The increasing incidence of melanoma and the lack of effective therapy on the disseminated form have led to an urgent need for new specific therapies. Several iodobenzamides or analogs are known to possess specific affinity for melanoma tissue. New heteroaromatic derivatives have been designed with a cytotoxic moiety and termed DNA intercalating agents. These compounds could be applied in targeted radionuclide therapy using (125)I, which emits Auger electrons and gives high-energy, localized irradiation. Two iodinated acridine derivatives have been reported to present an in vivo kinetic profile conducive to application in targeted radionuclide therapy. The aim of the present study was to perform a preclinical evaluation of these compounds. The DNA intercalating property was confirmed for both compounds. After radiolabeling with (125)I, the two compounds induced in vitro a significant radiotoxicity to B16F0 melanoma cells. Nevertheless, the acridine compound appeared more radiotoxic than the acridone compound. While cellular uptake was similar for both compounds, SIMS analysis and in vitro protocol showed a stronger affinity for melanin with acridone derivative, which was able to induce a predominant scavenging process in the melanosome and restrict access to the nucleus. In conclusion, the acridine derivative with a higher nuclear localization appeared a better candidate for application in targeted radionuclide therapy using (125)I.