Dlk/ZIP kinase-induced apoptosis in human medulloblastoma cells: requirement of the mitochondrial apoptosis pathway

Br J Cancer. 2001 Nov 30;85(11):1801-8. doi: 10.1054/bjoc.2001.2158.

Abstract

Dlk/ZIP kinase is a member of the Death Associated Protein (DAP) kinase family of pro-apoptotic serine/threonine kinases that have been implicated in regulation of apoptosis and tumour suppression. Expression of both Dlk/ZIP kinase and its interaction partner Par-4 is maintained in four medulloblastoma cell lines investigated, whereas three of seven neuroblastoma cell lines have lost expression of Par-4. Overexpression of a constitutively pro-apoptotic deletion mutant of Dlk/ZIP kinase induced significant apoptosis in D283 medulloblastoma cells. Cell death was characterized by apoptotic membrane blebbing, and a late stage during which the cells had ceased blebbing and were drastically shrunken or disrupted into apoptotic bodies. Over-expression of the anti-apoptotic Bcl-xL protein had no effect on Dlk/ZIP kinase-induced membrane blebbing, but potently inhibited Dlk/ZIP kinase-induced cytochrome c release and transition of cells to late stage apoptosis. Treatment with caspase inhibitors delayed, but did not prevent entry into late stage apoptosis. These results demonstrate that Dlk/ZIP kinase-triggered apoptosis involves the mitochondrial apoptosis pathway. However, cell death proceeded in the presence of caspase inhibitors, suggesting that Dlk/ZIP kinase is able to activate alternative cell death pathways. Alterations of signal transduction pathways leading to Dlk/ZIP kinase induced apoptosis or loss of expression of upstream activators could play important roles in tumour progression and metastasis of neural tumours.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Chloromethyl Ketones / pharmacology
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Apoptosis / physiology*
  • Apoptosis Regulatory Proteins
  • Calcium-Calmodulin-Dependent Protein Kinases
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Caspase Inhibitors
  • Cysteine Proteinase Inhibitors / pharmacology
  • Cytochrome c Group / metabolism
  • Death-Associated Protein Kinases
  • Gene Expression Regulation, Neoplastic
  • Green Fluorescent Proteins
  • Humans
  • Intracellular Membranes / metabolism
  • Intracellular Signaling Peptides and Proteins*
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Medulloblastoma / enzymology
  • Medulloblastoma / genetics
  • Medulloblastoma / pathology*
  • Microscopy, Fluorescence
  • Mitochondria / enzymology
  • Mitochondria / genetics
  • Mitochondria / pathology
  • Mutation
  • Neuroblastoma / enzymology
  • Neuroblastoma / genetics
  • Neuroblastoma / pathology
  • Oligopeptides / pharmacology
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Signal Transduction
  • Transfection
  • Tumor Cells, Cultured
  • bcl-X Protein

Substances

  • Amino Acid Chloromethyl Ketones
  • Apoptosis Regulatory Proteins
  • BCL2L1 protein, human
  • Carrier Proteins
  • Caspase Inhibitors
  • Cysteine Proteinase Inhibitors
  • Cytochrome c Group
  • Intracellular Signaling Peptides and Proteins
  • Luminescent Proteins
  • Oligopeptides
  • Proto-Oncogene Proteins c-bcl-2
  • Recombinant Fusion Proteins
  • acetyl-aspartyl-glutamyl-valyl-aspartal
  • bcl-X Protein
  • benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
  • prostate apoptosis response-4 protein
  • L 709049
  • Green Fluorescent Proteins
  • Death-Associated Protein Kinases
  • Protein Serine-Threonine Kinases
  • Calcium-Calmodulin-Dependent Protein Kinases