Efficacy of a novel integrin-targeted anti-c-Myc nanotherapy against multiple myeloma in mice (1054.11)

The MYC oncoprotein drives multiple myeloma (MM) pathogenesis, but the utility of small molecule inhibitors of MYC-MAX dimerization is limited by poor efficacy. We first sought to test the efficacy of a novel MYC-MAX dimerization inhibitor prodrug. Treatment of three MM cell lines (mouse and human) with a lipase-labile prodrug inhibitor of MYC-MAX dimerization (MI1-PD) decreased cell viability more than parent drug MI1 on an equimolar basis and increased apoptosis. However, MI1-PD is hydrophobic, limiting translation to in vivo use. To overcome this challenge, we next determined if the efficacy of MI1-PD could be improved by delivery in nanoparticles targeted to MM-specific integrins. Integrin-targeted, MI1-PD-containing nanoparticles inhibited growth and induced apoptosis compared to control nanoparticles without drug, or without integrin-targeting. Binding and efficacy of nanoparticles correlated with integrin expression in target cells. A mouse model of MM was used to assess in vivo efficacy of nanopar...