Targeted restoration of down-regulated DAPK2 tumor suppressor activity induces apoptosis in Hodgkin lymphoma cells

J Immunother. 2009 Jun;32(5):431-41. doi: 10.1097/CJI.0b013e31819f1cb6.

Abstract

Death-associated protein kinase 2 (DAPK2) is a calcium/calmodulin-regulated proapoptotic serine/threonine kinase that acts as a tumor suppressor. Here we show that DAPK2 is down-regulated in Hodgkin lymphoma-derived tumor cell lines and that promoter-region hypermethylation is one mechanism for DAPK2 inactivation. To determine whether selective reconstitution of DAPK2 catalytic activity in these cells could induce apoptosis, we created a fusion protein comprising a human CD30 ligand conjugated to a human DAPK2 calmodulin-deletion mutant. Thus, recombinant immunokinase DAPK2'-CD30L has a constitutive kinase activity with enhanced proapoptotic function. We show that this immunokinase fusion protein inhibits cell proliferation and induces apoptotic cell death specifically in CD30/DAPK2-negative tumor cell lines. This proof-of-concept study provides the first demonstration of therapeutic strategies based on the restoration of a defective, tumor-suppressing kinase activity by a novel class of recombinant immunotherapeutics.

MeSH terms

  • Apoptosis / genetics
  • Apoptosis / immunology
  • Apoptosis Regulatory Proteins / chemistry
  • Apoptosis Regulatory Proteins / genetics
  • Apoptosis Regulatory Proteins / immunology
  • Apoptosis Regulatory Proteins / metabolism*
  • CD30 Ligand / genetics
  • CD30 Ligand / immunology
  • CD30 Ligand / metabolism*
  • Calcium-Calmodulin-Dependent Protein Kinases / chemistry
  • Calcium-Calmodulin-Dependent Protein Kinases / genetics
  • Calcium-Calmodulin-Dependent Protein Kinases / immunology
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation
  • DNA Methylation
  • Death-Associated Protein Kinases
  • Down-Regulation
  • Gene Expression Regulation, Enzymologic
  • Hodgkin Disease / enzymology
  • Hodgkin Disease / genetics
  • Hodgkin Disease / immunology*
  • Hodgkin Disease / pathology
  • Hodgkin Disease / therapy
  • Humans
  • Immunotherapy*
  • Protein Engineering
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology
  • Recombinant Fusion Proteins / metabolism*
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / immunology
  • Tumor Suppressor Proteins / metabolism*
  • U937 Cells

Substances

  • Apoptosis Regulatory Proteins
  • CD30 Ligand
  • Recombinant Fusion Proteins
  • TNFSF8 protein, human
  • Tumor Suppressor Proteins
  • DAPK2'-CD30L fusion protein
  • DAPK2 protein, human
  • Death-Associated Protein Kinases
  • Calcium-Calmodulin-Dependent Protein Kinases