Structural Basis of Microtubule Destabilization by Potent Auristatin Anti-Mitotics

PLoS One. 2016 Aug 12;11(8):e0160890. doi: 10.1371/journal.pone.0160890. eCollection 2016.

Abstract

The auristatin class of microtubule destabilizers are highly potent cytotoxic agents against several cancer cell types when delivered as antibody drug conjugates. Here we describe the high resolution structures of tubulin in complex with both monomethyl auristatin E and F and unambiguously define the trans-configuration of both ligands at the Val-Dil amide bond in their tubulin bound state. Moreover, we illustrate how peptidic vinca-site agents carrying terminal carboxylate residues may exploit an observed extended hydrogen bond network with the M-loop Arg278 to greatly improve the affinity of the corresponding analogs and to maintain the M-loop in an incompatible conformation for productive lateral tubulin-tubulin contacts in microtubules. Our results highlight a potential, previously undescribed molecular mechanism by which peptidic vinca-site agents maintain unparalleled potency as microtubule-destabilizing agents.

MeSH terms

  • Aminobenzoates / chemistry*
  • Aminobenzoates / metabolism
  • Aminobenzoates / pharmacology*
  • Animals
  • Microtubules / drug effects*
  • Microtubules / metabolism*
  • Mitosis / drug effects*
  • Models, Molecular
  • Oligopeptides / chemistry*
  • Oligopeptides / metabolism
  • Oligopeptides / pharmacology*
  • Protein Multimerization / drug effects
  • Protein Stability / drug effects
  • Protein Structure, Quaternary
  • Sheep
  • Stereoisomerism
  • Structure-Activity Relationship
  • Tubulin / chemistry
  • Tubulin / metabolism
  • Tubulin Modulators / chemistry
  • Tubulin Modulators / metabolism
  • Tubulin Modulators / pharmacology
  • Vinblastine / metabolism
  • Vinblastine / pharmacology

Substances

  • Aminobenzoates
  • Oligopeptides
  • Tubulin
  • Tubulin Modulators
  • auristatin
  • Vinblastine

Grants and funding

The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. This work was supported by a grant from the Swiss National Science Foundation (310030B_138659 to MOS). Portions of this work were done under a Sponsored Research Agreement funded by Seattle Genetics Inc., which is developing antibody-drug conjugate technology including Monomethylauristatin E based ADCs like ADCETRIS® (Brentuximab Vedotin). ABW, SD and DS are current full-time employees of Seattle Genetics and did play a role in our study design, data collection and analysis, decision to publish and preparation of the manuscript. All other authors of this manuscript declare no financial interest related to this work.