HSP70 inhibition by 2-phenylethynesulfonamide induces lysosomal cathepsin D release and immunogenic cell death in primary effusion lymphoma

Cell Death Dis. 2013 Jul 18;4(7):e730. doi: 10.1038/cddis.2013.263.

Abstract

Heat-shock protein (HSP) 70 is aberrantly expressed in different malignancies and has a cancer-specific cell-protective effect. As such, it has emerged as a promising target for anticancer therapy. In this study, the effect of the HSP70-specific inhibitor (PES), also Pifitrin-μ, on primary effusion lymphoma (PEL) cell viability was analyzed. PES treatment induced a dose- and time-dependent cytotoxic effect in BC3 and BCBL1 PEL cells by inducing lysosome membrane permeabilization, relocation of cathepsin D in the cytosol, Bid cleavage, mitochondrial depolarization with release and nuclear translocation of apoptosis-activating factor. The PES-induced cell death in PEL cells was characterized by the appearance of Annexin-V/propidium iodide double-positive cells from the early times of treatment, indicating the occurrence of an additional type of cell death other than apoptosis, which, accordingly, was not efficiently prevented by the pan-caspase inhibitor Z-VAD-fmk. Conversely, PES-induced cell death was robustly reduced by pepstatin A, which inhibits Bid and caspase 8 processing. In addition, PES was responsible for a block of the autophagic process in PEL cells. Finally, we found that PES-induced cell death has immunogenic potential being able to induce dendritic cell activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Antineoplastic Agents / pharmacology*
  • Apoptosis Inducing Factor / metabolism
  • Autophagy*
  • BH3 Interacting Domain Death Agonist Protein / metabolism
  • Cathepsin D / antagonists & inhibitors
  • Cathepsin D / metabolism*
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Dendritic Cells / drug effects
  • Dendritic Cells / immunology
  • Drug Screening Assays, Antitumor
  • HSP70 Heat-Shock Proteins / antagonists & inhibitors*
  • HSP70 Heat-Shock Proteins / metabolism
  • Humans
  • Lymphoma, Primary Effusion
  • Lysosomes / drug effects*
  • Lysosomes / enzymology
  • Mitochondrial Membranes / drug effects
  • Mitochondrial Membranes / metabolism
  • Pepstatins / pharmacology
  • Permeability
  • Protease Inhibitors / pharmacology
  • Sulfonamides / pharmacology*

Substances

  • 2-phenylacetylenesulfonamide
  • AIFM1 protein, human
  • Antineoplastic Agents
  • Apoptosis Inducing Factor
  • BH3 Interacting Domain Death Agonist Protein
  • BID protein, human
  • HSP70 Heat-Shock Proteins
  • Pepstatins
  • Protease Inhibitors
  • Sulfonamides
  • Cathepsin D
  • pepstatin