PK11195 inhibits mitophagy targeting the F1Fo-ATPsynthase in Bcl-2 knock-down cells

Curr Mol Med. 2012 May;12(4):476-82. doi: 10.2174/156652412800163406.

Abstract

The pharmacological agent 1-(2-Chlorophenyl-N-methylpropyl)-3-isoquinolinecarboxamide (PK11195) is the prototypical ligand of the 18-kDa Translocator Protein (TSPO) but at μM concentrations deactivates the oncoprotein Bcl-2 increasing the efficiency of chemotherapeutic agents and promoting the Ca2+-dependent macro-autophagy (or autophagy). In this paper, we report that PK11195, in HeLa cells, modifies the mitochondria-targeted type of autophagy--hereafter referred to as mitophagy--and the associated resizing of the mitochondrial network but does so exclusively in absence of the oncoprotein Bcl-2 (Bcl-2 Kd cells). This is consequence of a "side" targeting of the mitochondrial F1Fo-ATPsynthase enzyme, since identical outcome is mimicked by the antibiotic Oligomycin, of which PK11195 matches the effect on: i) mitochondrial membrane potential (ΔΨm), ii) ATP homeostasis and iii) Reactive Oxygen Species (ROS) generation. Taken together, these data highlight a novel TSPO-independent biological effect for PK11195 and provide evidences for a hitherto uncovered Bcl-2-dependent role of the F1Fo-ATPsynthase in mitochondrial quality control.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Autophagy / drug effects*
  • Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / pharmacology
  • Gene Knockdown Techniques
  • HeLa Cells
  • Humans
  • Isoquinolines / pharmacology*
  • Kinetics
  • Membrane Potential, Mitochondrial / drug effects
  • Microtubule-Associated Proteins / metabolism
  • Mitochondria / metabolism
  • Oligomycins / pharmacology
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Proton Ionophores / pharmacology
  • Proton-Translocating ATPases / antagonists & inhibitors
  • Proton-Translocating ATPases / metabolism*
  • Uncoupling Agents / pharmacology

Substances

  • Isoquinolines
  • MAP1LC3A protein, human
  • Microtubule-Associated Proteins
  • Oligomycins
  • Proto-Oncogene Proteins c-bcl-2
  • Proton Ionophores
  • Uncoupling Agents
  • Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone
  • Adenosine Triphosphate
  • Proton-Translocating ATPases
  • PK 11195