TAIP%20induces%20apoptosis%20in%20hepatocellular%20carcinoma-derived%20cells

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TAIP induces apoptosis in hepatocellular
carcinoma-derived cells
Klaas Kooistra Biological Chemistry, Molecular
Genetics LIC, Leiden University LC Workshop
Proteins killing Tumour Cells November 1, 2007
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Menu

• A specific TT virus strain has a CAV-like genome
• TTV protein (TAIP) harbors apoptin-like
  characteristics?
• Amino-acid sequence similarities?
• Apoptosis?
• TAIP-studies in human tumor cell lines

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Specific TT virus (TTV) strain

• TT viruses belong to human circoviridae
• Single stranded circular DNA virus
• Within TT viruses a very high genetic variability
  exists
• TTV strain (GenBank AB008394) described by
  Miyata
• Isolated from Japanese patient with non-A-E
  hepatitis
• Attracted our specific attention for ..

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TTV-strain has CAV-like genomic organization
TAIP
Apoptin
TTV torque teno virus CAV chicken anemia virus
Miyata et al. 1999
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TAIP amino acid sequence shows similarities
with apoptins
Hydrophobic a.a. stretches Proline distribution
Thr/Ser-rich
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Expression of TAIP in human tumor cells
Putative TTV-derived TAIP of 105 a.a.
Approach 0.36 kb Myc-TAIP DNA was synthesized
(Midland, USA) Cloned in pCMV-expression vector
TAIP production in COS-1 cells
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TAIP
Cytoplasmic TAIP induces apoptosis in HUH-7 cells
TAIP DNA
apoptin
apoptin DNA
IFA / HUH-7 cells
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TAIP induces apoptosis human HCC cells
Transient transfection of three human
hepatocellular carcinoma (HCC) cell lines
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TAIP induces much less apoptosis in non-HCC
Transient transfection of three non-HCC cell lines
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TAIP-induces apoptosis in HCC significantly more
than in non-HCC
Preliminary results TAIP does not induce
apoptosis in normal rat hepatocytes
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Conclusions
TAIP induces p53 independent apoptosis TAIP
induces apoptosis preferentially in HCC
cells TAIP is localized in the cytoplasm in
cancer cells TAIP non-toxic for normal cells (?)
TAIP functions differently than apoptin?!
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Acknowledgements Ying-Hui Zhang Niek
Hendriquez Bertram Weiss Dominik Mumberg Mathieu
Noteborn
Thank you for your attention
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Literature of interest

1. Miyata et al., Identification of a novel GC-rich
   113-nucleotide region to complete the circular,
   single-stranded DNA genome of TT virus, the first
   human circovirus.J Virol. 1999
   May73(5)3582-6.
2. Kooistra et al., TT virus-derived
   apoptosis-inducing protein induces apoptosis
   preferentially in hepatocellular
   carcinoma-derived cells.J Gen Virol. 2004
   Jun85(Pt 6)1445-50.
3. Hino and Miyata, Torque teno virus (TTV) current
   status.Rev Med Virol. 2007 Jan-Feb17(1)45-57.