A synthetic cell-penetrating dominant-negative ATF5 peptide exerts anticancer activity against a broad spectrum of treatment-resistant cancers

Georg Karpel-Massler, Basil A. Horst, Chang Shu, Lily Chau, Takashi Tsujiuchi, Jeffrey N. Bruce, Peter Canoll, Lloyd A. Greene, James M Angelastro, Markus D. Siegelin

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

Purpose: Despite significant progress in cancer research, many tumor entities still have an unfavorable prognosis. Activating transcription factor 5 (ATF5) is upregulated in various malignancies and promotes apoptotic resistance. We evaluated the efficacy and mechanisms of the first described synthetic cell-penetrating inhibitor of ATF5 function, CP-d/n-ATF5-S1. Experimental Design: Preclinical drug testing was performed in various treatment-resistant cancer cells and in vivo xenograft models. Results: CP-d/n-ATF5-S1 reduced the transcript levels of several known direct ATF5 targets. It depleted endogenous ATF5 and induced apoptosis across a broad panel of treatment-refractory cancer cell lines, sparing non-neoplastic cells. CP-d/n-ATF5-S1 promoted tumor cell apoptotic susceptibility in part by reducing expression of the deubiquitinase Usp9X and led to diminished levels of antiapoptotic Bcl-2 family members Mcl-1 and Bcl-2. In line with this, CP-d/n-ATF5-S1 synergistically enhanced tumor cell apoptosis induced by the BH3-mimetic ABT263 and the death ligand TRAIL. In vivo, CP-d/n-ATF5-S1 attenuated tumor growth as a single compound in glioblastoma, melanoma, prostate cancer, and triple receptor-negative breast cancer xenograft models. Finally, the combination treatment of CP-d/n-ATF5-S1 and ABT263 significantly reduced tumor growth in vivo more efficiently than each reagent on its own. Conclusions: Our data support the idea that CP-d/n-ATF5-S1, administered as a single reagent or in combination with other drugs, holds promise as an innovative, safe, and efficient antineoplastic agent against treatment-resistant cancers. Clin Cancer Res; 22(18); 4698-711.

Original languageEnglish (US)
Pages (from-to)4698-4711
Number of pages14
JournalClinical Cancer Research
Volume22
Issue number18
DOIs
StatePublished - Sep 15 2016

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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    Karpel-Massler, G., Horst, B. A., Shu, C., Chau, L., Tsujiuchi, T., Bruce, J. N., Canoll, P., Greene, L. A., Angelastro, J. M., & Siegelin, M. D. (2016). A synthetic cell-penetrating dominant-negative ATF5 peptide exerts anticancer activity against a broad spectrum of treatment-resistant cancers. Clinical Cancer Research, 22(18), 4698-4711. https://doi.org/10.1158/1078-0432.CCR-15-2827