gms | German Medical Science

128. Kongress der Deutschen Gesellschaft für Chirurgie

Deutsche Gesellschaft für Chirurgie

03.05. - 06.05.2011, München

Inhibiting hepatoblastoma growth in vitro and in vivo through blocking IGF2-AKT-mTOR-signaling

Meeting Abstract

  • Ferdinand Wagner - Dr. von Hauner'sches Kinderspital, Kinderchirurgie, München
  • Bente Henningsen - Dr. von Hauner'sches Kinderspital, Kinderchirurgie, München
  • Melanie Eichenmüller - Dr. von Hauner'sches Kinderspital, Kinderchirurgie, München
  • Beate Hagl - Dr. von Hauner'sches Kinderspital, Kinderchirurgie, München
  • Jan Gödeke - Dr. von Hauner'sches Kinderspital, Kinderchirurgie, München
  • Roland Kappler - Dr. von Hauner'sches Kinderspital, Kinderchirurgie, München
  • Dietrich von Schweinitz - Dr. von Hauner'sches Kinderspital, Kinderchirurgie, München

Deutsche Gesellschaft für Chirurgie. 128. Kongress der Deutschen Gesellschaft für Chirurgie. München, 03.-06.05.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. Doc11dgch551

DOI: 10.3205/11dgch551, URN: urn:nbn:de:0183-11dgch5510

Veröffentlicht: 20. Mai 2011

© 2011 Wagner et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Introduction: Hepatoblastoma is the most common malignant liver tumor in childhood. Since activation of IGF2-AKT-mTOR signaling plays a central role in the formation of embryonal tumors, blocking this pathway with rapamycin might be a new option for hepatoblastoma treatment.

Materials and methods: Tumor biopsies (n=23) of histologically confirmed hepatoblastomas were analyzed for the expression of IGF1-receptor (IGF1R), IGF1 and IGF2, IGF-binding protein 3 (IGFBP3) and oncogene pleomorphic adenoma gene 1 (PLAG1) by means of RT-PCR. Activation of IGF2-signaling was investigated by detecting phosphorylated AKT (pAKT) in hepatoblastoma cell lines (HUH6, HepT1, HepG2) via Western blot. Proliferation was measured using MTT assay after incubating the cells with rapamycin. Apoptosis was quantified via immunohistochemical staining for caspase 3 (Casp3). Dephosphorylation and deactivation of the IGF2-AKT signaling pathway components p70S6K and 4E-BP1 have been measured using Western blot. 7 HUH6 subcutaneous tumor bearing mice were treated with rapamycin 5mg/kg/d p.o. for 21 days. 7 untreated mice served as control. Animals were investigated in terms of tumor volume. On day 21 blood was taken to measure AFP serum levels.

Results: We detected an overexpression of IGF2 (16/23), IGF1R and PLAG1 (20/23) in the majority of tumors. The inhibitory signaling component IGFBP3 (20/23) showed a diminished expression. IGF1 expression was hardly detectable. Phosphorylation of AKT was detected in HUH6 and HepT1, but not HepG2 cells. Rapamycin induced dephosphorylation of p70S6K, 4E-BP1 was not influenced. Rapamycin induced a significant dose-dependent inhibition in proliferation and a trend towards enhanced levels of apoptosis in all cell lines. In our mouse model there was a significant inhibition of tumor growth in terms of a decreased tumor volume after 21 days in the rapamycin treated group. There was no difference in AFP blood levels.

Conclusion: Rapamycin inhibits hepatoblastoma growth in vitro and in vivo and is a promising candidate for future use in clinical trials.