Non-Toxic Chemical Interdiction of the Epithelial-to-Mesenchymal Transition by Targeting Cap-dependent Translation

摘要

Normal growth and development depends upon high fidelity regulation of cap-dependent translation initiation; a process that is usurped and redirected in cancer to mediate acquisition of malignant properties. The epithelial-to-mesenchymal transition (EMT) is a key translationally-regulated step in the development of epithelial cancers as well as pathological tissue fibrosis (–). To date, no compounds targeting EMT have been developed. Here we report the synthesis of a novel class of Histidine Triad Nucleotide Binding Protein (HINT)-dependent pronucleotides that interdict EMT by negatively regulating the association of eIF4E with the mRNA cap. Compound eIF4E inhibitor-1 (>4Ei-1) potently inhibited cap-dependent translation in a dose-dependent manner in zebrafish embryos without causing developmental abnormalities; and prevented eIF4E from triggering EMT in zebrafish ectoderm explants without toxicity. Metabolism studies with whole cell lysates demonstrated that the prodrug was rapidly converted into 7-Bn-GMP. Thus we have successfully developed the first non-toxic small molecule able to inhibit EMT, a key process in the development of epithelial cancer and tissue fibrosis by targeting the interaction of eIF4E with the mRNA cap; and demonstrate the tractability of zebrafish as a model organism for studying agents that modulate EMT. Our work provides strong motivation for the continued development of compounds designed to normalize cap-dependent translation as novel chemo-preventive agents and therapeutics for cancer and fibrosis.