Abstract 350: Investigating the mechanisms of cellular uptake and metabolism of ICT2588, an MT-MMP-activated prodrug

Abstract

Abstract ICT2588 is a non-toxic MT1-MMP-activated peptide prodrug of the potent vascular disrupting agent (VDA) azademethylcolchicine [1]. ICT2588 produces significant tumor-selective delivery (≥10-fold) of the toxic and potent azademethylcolchicine, as compared to the administration of azademethylcolchicine alone, in murine models of human colorectal, breast, lung and prostate cancers. In addition, ICT2588 exhibited reduced potential for toxicity, and cardiotoxicity in particular (a phenomenon associated with most VDAs) as a result of its metabolic stability in plasma and normal tissues [2]. ICT2588 is progressing towards clinical evaluation in the UK in 2019. In this study we aim to further investigate the cellular uptake and metabolism of ICT2588 and related compounds in MT1-MMP positive (HT1080) and MT1-MMP negative (MCF-7) cells in vitro. ICT2588 and related compounds were synthesized in-house and purified by preparative HPLC in excellent yield and purity. Activation of ICT2588 by recombinant MT1-MMP and its preferential metabolism in MT1-MMP positive tumor xenograft homogenates has been shown previously [1]. We are currently studying the mechanism of cellular uptake and metabolism of these peptide prodrugs by incubating these compounds in HT1080 and MCF-7 cell cultures. Cellular concentrations of ICT2588 and all metabolites identified were determined using RP-HPLC, mass spectrometry and immunofluorescent microscopy. We describe the first data on the cellular mechanism of uptake and metabolism of ICT2588 and related peptide prodrugs in cancer cells. Our findings have important implications in the future design of effective peptide-based tumor-targeted prodrugs. Reference: [1] Atkinson, J.M et al “Development of a tumor-targeted vascular disrupting agent activated by Membrane-type Matrix Metalloproteinases (MT-MMPs).” Cancer Research, 2010, 70, 6902-12. [2] Gill, J.H et al “Tumor-targeted prodrug ICT2588 demonstrates therapeutic activity against solid tumors and reduced potential for cardiovascular toxicity”. Mol Pharm. 2014,11:1294-300. Citation Format: Francis Mprah Barnieh, Amanda D. Race, Steven D. Shnyder, Paul M. Loadman, Robert A. Falconer. Investigating the mechanisms of cellular uptake and metabolism of ICT2588, an MT-MMP-activated prodrug [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 350.