uPAR and cathepsin B downregulation induces apoptosis by targeting calcineurin A to BAD via Bcl-2 in glioma

J Neurooncol. 2012 Mar;107(1):69-80. doi: 10.1007/s11060-011-0727-x. Epub 2011 Oct 2.

Abstract

Cathepsin B and urokinase plasminogen activator receptor (uPAR) are postulated to play key roles in glioma invasion. Calcineurin is one of the key regulators of mitochondrial-dependent apoptosis, but its mechanism is poorly understood. Hence, we studied subcellular localization of calcineurin after transcriptional downregulation of uPAR and cathepsin B in glioma. In the present study, efficient downregulation of uPAR and cathepsin B increased the translocation of calcineurin A from the mitochondria to the cytosol, decreased pBAD (S136) expression and its interaction with 14-3-3ζ and increased the interaction of BAD with Bcl-xl. Co-depletion of uPAR and cathepsin B induced mitochondrial translocation of BAD, activation of caspase 3 as well as PARP and cytochrome c and SMAC release. These effects were inhibited by FK506 (10 μM), a specific inhibitor of calcineurin. Calcineurin A was co-localized and also co-immunoprecipitated with Bcl-2. This interaction decreased with co-depletion of uPAR and cathepsin B and also with Bcl-2 inhibitor, HA 14-1 (20 μg/ml). Altered localization and interaction of calcineurin A with Bcl-2 was also observed in vivo when uPAR and cathepsin B were downregulated. In conclusion, downregulation of uPAR and cathepsin B induced apoptosis by targeting calcineurin A to BAD via Bcl-2 in glioma.

Publication types

  • Research Support, N.I.H., Extramural
  • Retracted Publication

MeSH terms

  • Apoptosis*
  • Blotting, Western
  • Calcineurin / metabolism*
  • Caspase 3 / metabolism
  • Cathepsin B / antagonists & inhibitors
  • Cathepsin B / metabolism*
  • Cell Line, Tumor
  • Cytochromes c / metabolism
  • Down-Regulation
  • Fluorescent Antibody Technique
  • Glioma / metabolism*
  • Glioma / pathology*
  • Humans
  • Immunoenzyme Techniques
  • Immunoprecipitation
  • Membrane Potential, Mitochondrial
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Receptors, Urokinase Plasminogen Activator / antagonists & inhibitors
  • Receptors, Urokinase Plasminogen Activator / metabolism*
  • Signal Transduction
  • Subcellular Fractions
  • bcl-Associated Death Protein / metabolism*

Substances

  • BAD protein, human
  • Proto-Oncogene Proteins c-bcl-2
  • Receptors, Urokinase Plasminogen Activator
  • bcl-Associated Death Protein
  • Cytochromes c
  • Calcineurin
  • Caspase 3
  • Cathepsin B