The objective of this proposal is to define the in vivo effectiveness of a melanoma-targeted nanoparticle for systemic therapeutic delivery. The approach is to utilize a ?clinically experienced"""""""" fusogenic bilamellar invaginated vesicle nanoparticle (BIV NP) with a manually extruded DOTAP:cholesterol formulation for the systemic delivery of DNA and RNAi expression plasmids. This will involve the preclinical validation of two recent technological advances: reversible masking and tumor-specific ligand decoration. Reversible masking is a non-toxic alternative to pegylation and involves transient coating with small, uncharged, lipids to bypass non-targeted organs and re-exposure of charge at the target cells for enhanced transfection. Further, the BIV NP will be decorated with low mw, non-immunogenic beta-turn """"""""semi-peptidic"""""""" small molecules that mimic secondary structure motifs found at hot-spots in protein-ligand interactions. The small molecule candidate is selected by screening with melanoma cell lines and patient primary cultures for enhanced transgene expression. The project will include: 1) prioritization of low mw ligands that promote BIV-delivered transgene expression;2) demonstration in nu/nu-hu melanoma xenograft models of the enhanced expression and anti-tumor activity of BIV NPs with pre-established anti-oncogene activities (bi-shSTMN1 payload);and 3) implementation of a GMP manufacturing process for the formulated melanoma-targeted, reversibly-masked bi-shSTMN1-BIV product. These activities will pave the way for future safety/toxicology studies and early phase clinical trials.