Bcl-2 Gene Silencing in Pediatric Epithelial Liver Tumors

Warmann, Steven W.; Frank, Heike; Heitmann, Heike; Ruck, Peter; Herberts, Tina; Seitz, Guido; Fuchs, Jörg

doi:10.1016/j.jss.2007.03.054

« Previous Next »Journal of Surgical Research
Volume 144, Issue 1 , Pages 43-48, January 2008

Bcl-2 Gene Silencing in Pediatric Epithelial Liver Tumors

Steven W. Warmann, M.D.
- Department of Pediatric Surgery, University Children’s Hospital Tübingen, Tübingen, Germany
- To whom correspondence and reprint requests should be addressed at Department of Pediatric Surgery, University Children’s Hospital Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany.
Heike Frank
- Department of Pediatric Surgery, University Children’s Hospital Tübingen, Tübingen, Germany
Heike Heitmann
- Department of Pediatric Surgery, University Children’s Hospital Tübingen, Tübingen, Germany
Peter Ruck, M.D.
- Institute of Pathology, Leonberg, Germany
Tina Herberts, M.D.
- Department of Medical Biometry, University of Tübingen, Tübingen, Germany
Guido Seitz, M.D.
- Department of Pediatric Surgery, University Children’s Hospital Tübingen, Tübingen, Germany
Jörg Fuchs, M.D.
- Department of Pediatric Surgery, University Children’s Hospital Tübingen, Tübingen, Germany

Received 10 October 2006 published online 16 June 2007.

Background

Proteins of the Bcl-2 family prevent cells of various tumor types from undergoing apoptosis and thus contribute to their chemotherapy resistance. The phenotype of multidrug resistance is a major factor for poor treatment results of advanced epithelial liver tumors in children. The role of Bcl-2 proteins in these tumors is yet unclear. The purpose of this study was to analyze the influence of Bcl-2 on the chemotherapy resistance of hepatoblastoma (HB) and pediatric hepatocellular carcinoma (HCC).

Materials and methods

Bcl-2 expression was analyzed in the HB cell lines HUH6 and HepT1 as well as in the HCC cell line HepG2 before and after treatment with cisplatin, doxorubicin, taxol, and etoposid. Silencing of the Bcl-2 gene was performed via RNA interference using specific siRNA. Treatment efficiencies of cytotoxic agents were assessed against original and Bcl-2 siRNA transfected tumor cells.

Results

The mixed HB cell line HUH6 showed a relevant amount of Bcl-2 expression, which increased after chemotherapy. In these cells Bcl-2 appeared within the nuclei and the cytosol. Treatment with all cytotoxic agents was significantly improved through Bcl-2 siRNA (P < 0.001–0.0054) in this cell line. There was no effect of Bcl-2 siRNA in HepT1 and HepG2 cells.

Conclusions

Bcl-2 seems to play a role in antiapoptotic mechanisms of some HB subtypes. Thus, this gene might serve as target for a gene-directed adjuvant therapy. Further studies seem necessary to clear the susceptibility of pediatric epithelial liver tumors toward the described approach.

Key Words: hepatoblastoma, hepatocellular carcinoma, apoptosis, Bcl-2 gene, gene silencing, siRNA