Discovery of Novel Targets for Melanoma Drug Discovery

Nova Southeastern University, Davie, Florida, USA

Objective. To identify target(s) and mechanism of action of novel anti-melanoma lead 2155-14. Background. Despite recent advances in melanoma drug discovery, the average overall survival of patients with late stage metastatic melanoma is approximately 3 years, suggesting a need for approaches that identify new melanoma targets. Methods. We utilized biotinylated analog of 2155-14 to pull down its targets from melanoma cells. Proteomics in combination with western blot were used to identify the targets. Mechanism of action of 2155-14 was determined using flow cytometry, RT-PCR, microscopy, western blot, and enzymatic activity assays. Results. We identified ATP-dependent RNA helicase DDX1 and heterogeneous nuclear ribonucleoproteins (hnRNPs) H1, H2 and A2/B1 as targets of anti-melanoma compound 2155-14. To the best of our knowledge, this is a first report suggesting that these proteins could be targeted for melanoma therapy. Mechanistic investigations showed that 2155-14 induces ER stress leading to potentiation of basal autophagy resulting in melanoma cell death in BRAF and NRAS mutated melanoma cells. Conclusion. Identification of mode of action of 2155-14 may provide insight into novel therapies against a broad range of melanoma subtypes. These studies were enabled by the novel probe derived from a mixture-based library, an important class of chemical biology tools for discovering novel targets. Grants. Auburn University Harrison School of Pharmacy Faculty start-up funds. TPIMS Faculty start-up funds. Auburn University Intramural Grant Program from Office of Vice President for Research. “Target Identification of Novel Anti-Melanoma Compounds”. Royal Dames of Cancer Research Inc., Ft. Lauderdale, Florida.