Proteomics reveal cap-dependent translation inhibitors remodel the translation machinery and translatome

  • Cell Rep. 2021 Oct 12;37(2):109806. doi: 10.1016/j.celrep.2021.109806.
J J David Ho  1 Tyler A Cunningham  2 Paola Manara  3 Caroline A Coughlin  4 Artavazd Arumov  3 Evan R Roberts  5 Ashanti Osteen  5 Preet Kumar  6 Daniel Bilbao  5 Jonathan R Krieger  7 Stephen Lee  8 Jonathan H Schatz  9
Affiliations
  • 1. Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Division of Hematology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA. Electronic address: [email protected].
  • 2. Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Medical Scientist Training Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Molecular and Cellular Pharmacology Graduate Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
  • 3. Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Sheila and David Fuente Graduate Program in Cancer Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
  • 4. Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Medical Scientist Training Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Sheila and David Fuente Graduate Program in Cancer Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
  • 5. Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Cancer Modeling Shared Resource, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
  • 6. Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Division of Hematology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
  • 7. Bioinformatics Solutions Inc., Waterloo, ON N2L 6J2, Canada.
  • 8. Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
  • 9. Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Division of Hematology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA. Electronic address: [email protected].
Abstract

Tactical disruption of protein synthesis is an attractive therapeutic strategy, with the first-in-class eIF4A-targeting compound zotatifin in clinical evaluation for Cancer and COVID-19. The full cellular impact and mechanisms of these potent molecules are undefined at a proteomic level. Here, we report mass spectrometry analysis of translational reprogramming by rocaglates, cap-dependent initiation disruptors that include zotatifin. We find effects to be far more complex than simple "translational inhibition" as currently defined. Translatome analysis by TMT-pSILAC (tandem mass tag-pulse stable isotope labeling with Amino acids in Cell Culture mass spectrometry) reveals myriad upregulated proteins that drive hitherto unrecognized cytotoxic mechanisms, including GEF-H1-mediated anti-survival RHOA/JNK activation. Surprisingly, these responses are not replicated by eIF4A silencing, indicating a broader translational adaptation than currently understood. Translation machinery analysis by MATRIX (mass spectrometry analysis of active translation factors using ribosome density fractionation and isotopic labeling experiments) identifies rocaglate-specific dependence on specific translation factors including eEF1ε1 that drive translatome remodeling. Our proteome-level interrogation reveals that the complete cellular response to these historical "translation inhibitors" is mediated by comprehensive translational landscape remodeling.

Keywords
DDX17; GEF-H1; JNK; RHOA; eEF1ε1; eIF4A; rocaglate; silvestrol; translation; zotatifin.
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