Ataxin-2 promotes apoptosis of human neuroblastoma cells.
Neuroblastoma is a highly heterogeneous tumor of young children. Although many advances have been made towards understanding the molecular mechanisms dictating the phenotypic heterogeneity, the prognosis of children with neuroblastoma, particularly of progressively growing variants, has remained dire. About 10% of neuroblastomas regress spontaneously, probably by apoptosis, while another 20% have amplified the MYCN gene resulting in a poor prognosis. In pursuit of identifying cell death-associated genes in neuroblastoma, we encountered the SCA2 gene, coding for ataxin-2, as an important player. Here, we report that enforced expression of wild-type ataxin-2, but not of mutant ataxin-2, sensitizes neuroblastoma cells for apoptosis. In line with this, higher levels of ataxin-2 were detected in apoptotic cells compared to nonapoptotic cells. Neuroblastoma tumors with amplified MYCN contain significantly less ataxin-2 protein than tumors without amplified MYCN. Collectively, our data suggest that ataxin-2 has an important role in regulating the susceptibility of neuroblastoma cells to apoptotic stimuli in vitro and in vivo.
Wiedemeyer
Ruprecht
R
Department of Cytogenetics (H0400), German Cancer Research Center, Heidelberg, Germany.
Westermann
Frank
F
Wittke
Isabel
I
Nowock
Joachim
J
Schwab
Manfred
M
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology*; D000067528:Ataxins; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004789:Enzyme Activation; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009154:Mutation; D000071447:N-Myc Proto-Oncogene Protein; D009419:Nerve Tissue Proteins; D009447:Neuroblastoma / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D009687:Nuclear Proteins / Q000235:genetics; D015513:Oncogene Proteins / Q000235:genetics; D010455:Peptides / Q000235:genetics; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
D000590:Amino Acid Chloromethyl Ketones; D000067528:Ataxins; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; C459801:MYCN protein, human; D000071447:N-Myc Proto-Oncogene Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D010455:Peptides; D011506:Proteins; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C097188:polyglutamine; D020169:Caspases