Death-associated protein 3 (Dap-3) is overexpressed in invasive glioblastoma cells in vivo and in glioma cell lines with induced motility phenotype in vitro.
OBJECTIVE
To discover the genetic determinants of glioma invasion in vivo, we compared the mRNA expression profiles of glioblastoma cells residing at the tumor core versus those at the invasive rim of a human tumor resection.


METHODS
From a single glioblastoma specimen, 20,000 individual cells from each region (core and invasive rim) were collected by laser capture microdissection and analyzed by mRNA differential display. Differential expression of gene candidates was confirmed by laser capture microdissection and quantitative reverse transcription-PCR in additional glioblastoma multiforme specimens, and the role in migration was further evaluated in glioma cell lines in vitro.


RESULTS
Reproducible overexpression the death-associated Protein 3 (Dap-3) mRNA (NM 004632, GenBank; also reported as human ionizing resistance conferring protein mRNA, HSU18321, GenBank) by invasive cells was identified. Although the full-length Dap-3 protein has been described as proapoptotic, the NH(2)-terminal fragment can act in a dominant negative way resulting in protection from programmed cell death. In glioma cell lines T98G and G112 with an induced motility phenotype, Dap-3 was up-regulated at the mRNA and protein level as assessed by quantitative reverse transcription-PCR, cDNA microarray, and Western blot analysis. These cells showed an increased resistance to undergo camptothecin-induced apoptosis, which was overcome by effective Dap-3-antisense treatment. Antisense treatment also decreased the migration ability of T98G cells.


CONCLUSIONS
Dap-3 is up-regulated in invasive glioblastoma multiforme cells in vivo and in glioma cells with an induced motility phenotype in vitro. When migration is activated, Dap-3 is up-regulated and cells become resistant to apoptosis. These findings suggest that Dap-3 confers apoptosis-resistance when migration behavior is engaged.
Mariani
L
L
Neuro-Oncology Laboratory, Barrow Neurological Institute, 350 West Thomas Road, Phoenix, AZ 85013, USA.
Beaudry
C
C
McDonough
W S
WS
Hoelzinger
D B
DB
Kaczmarek
E
E
Ponce
F
F
Coons
S W
SW
Giese
A
A
Seiler
R W
RW
Berens
M E
ME
D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D016373:DNA, Antisense / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005109:Extracellular Matrix / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005909:Glioblastoma / Q000235:genetics / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007797:Laminin / Q000494:pharmacology; D009361:Neoplasm Invasiveness; D010641:Phenotype; D011506:Proteins / Q000032:analysis / Q000235:genetics*; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins; D012269:Ribosomal Proteins; D014407:Tumor Cells, Cultured
D051017:Apoptosis Regulatory Proteins; C097041:DAP3 protein, human; D016373:DNA, Antisense; D007797:Laminin; D011506:Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012269:Ribosomal Proteins