The oncolytic compound LTX-401 targets the Golgi apparatus

Cell Death Differ. 2016 Dec;23(12):2031-2041. doi: 10.1038/cdd.2016.86. Epub 2016 Sep 2.

Abstract

LTX-401 is an oncolytic amino acid derivative with potential immunogenic properties. Here, we demonstrate that LTX-401 selectively destroys the structure of the Golgi apparatus, as determined by means of ultrastructural analyses and fluorescence microscopic observation of cells expressing Golgi-targeted GFP reporters. Subcellular fractionation followed by mass spectrometric detection revealed that LTX-401 selectively enriched in the Golgi rather than in mitochondria or in the cytosol. The Golgi-dissociating agent Brefeldin A (BFA) reduced cell killing by LTX-401 as it partially inhibited LTX-401-induced mitochondrial release of cytochrome c and the activation of BAX. The cytotoxic effect of LTX-401 was attenuated by the double knockout of BAX and BAK, as well as the mitophagy-enforced depletion of mitochondria, yet was refractory to caspase inhibition. LTX-401 induced all major hallmarks of immunogenic cell death detectable with biosensor cell lines including calreticulin exposure, ATP release, HMGB1 exodus and a type-1 interferon response. Moreover, LTX-401-treated tumors manifested a strong lymphoid infiltration. Altogether these results support the contention that LTX-401 can stimulate immunogenic cell death through a pathway in which Golgi-localized LTX-401 operates upstream of mitochondrial membrane permeabilization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Brefeldin A / pharmacology
  • Cell Line, Tumor
  • Golgi Apparatus / drug effects
  • Golgi Apparatus / metabolism*
  • Golgi Apparatus / ultrastructure
  • Humans
  • Mice, Inbred C57BL
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Mitochondria / ultrastructure
  • Mitochondrial Membranes / drug effects
  • Mitochondrial Membranes / metabolism
  • Oligopeptides / chemistry
  • Oligopeptides / pharmacology
  • Permeability
  • Subcellular Fractions / metabolism
  • beta-Alanine / analogs & derivatives*
  • beta-Alanine / chemistry
  • beta-Alanine / pharmacology

Substances

  • Antineoplastic Agents
  • LTX-315
  • LTX-401
  • Oligopeptides
  • beta-Alanine
  • Brefeldin A