LAUSR

Abstract Melphalan is an efficient chemotherapeutic agent that is currently used to treat retinoblastoma (Rb); however, the inherent risk of immunogenicity and the hazardous integration of this drug in healthy cells is inevitable. MicroRNAs are short non‐coding single‐stranded RNAs that affect a vast range of biological processes. Previously, we focused on the regulatory role of miR‐181a during cancer development and progression. In this manuscript, 171 nm switchable lipid nanoparticles (LNP) co‐delivered melphalan and miR‐181a with encapsulation efficiencies of 93%. Encapsulation of melphalan in LNP significantly improved its therapeutic efficiency. Gene analysis shows that miR‐181a decreases the expression of anti‐proliferative gene MAPK1 and anti‐apoptotic gene Bcl‐2, but significantly increased the expression of pro‐apoptotic gene BAX. Our results suggest that the two agents have a complementary effect in reducing the viability of cultured Rb cells (primary and cell line) and decreasing Rb cell counts in an in‐vivo xenograft Rb model in rats. Our results suggest that the proposed co‐delivery technique significantly increases the therapeutic impact, allows for lower administration of melphalan, and consequently, could minimize the cytotoxic side‐effects of this drug. Graphical abstract Figure. No Caption available.