gms | German Medical Science

27. Deutscher Krebskongress

Deutsche Krebsgesellschaft e. V.

22. - 26.03.2006, Berlin

Effects of inducible p53 reconstitution in an orthotopic mouse model of pancreatic cancer

Meeting Abstract

  • corresponding author presenting/speaker Noreen Otto - Charité, Universitätsklinikum Campus Virchow-Klinikum, Berlin, Deutschland
  • Petra Schulz - Charité, Universitätsklinikum Campus Virchow-Klinikum, Berlin
  • Arne Scholz - Charité, Universitätsklinikum Campus Virchow-Klinikum, Berlin
  • Annett Rexin - Charité, Universitätsklinikum Campus Virchow-Klinikum, Berlin
  • Peter Hauff - Research Laboratories, Schering AG, Berlin
  • Michael Schirner - Research Laboratories, Schering AG, Berlin
  • Bertram Wiedenmann - Charité, Universitätsklinikum Campus Virchow-Klinikum, Berlin
  • Katharina Detjen - Charité, Universitätsklinikum Campus Virchow-Klinikum, Berlin
  • Stefan Rosewicz - Charité, Universitätsklinikum Campus Virchow-Klinikum, Berlin

27. Deutscher Krebskongress. Berlin, 22.-26.03.2006. Düsseldorf, Köln: German Medical Science; 2006. DocPO126

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dkk2006/06dkk236.shtml

Veröffentlicht: 20. März 2006

© 2006 Otto 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 vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

The tumor suppressor p53 is inactivated in 50 to 70% of patients with pancreatic carcinoma. p53 has been extensively characterized at the molecular/cellular level, and key pathways that control cell cycle progression and survival have been delineated. However, much less is known about the contribution of p53 inactivation to the more complex phenotypic aspects of pancreatic carcinoma in vivo, such as tumor angiogenesis and metastasis. Here, we used an inducible system to reexpress wild type p53 (p53) in an orthotopic model of pancreatic cancer and examined the impact on tumor biology. To obtain an inducible expression of p53, p53 deficient MiaPaCa-2 were sequentially transfected with the vectors pcDNA6/TR and pcDNA4/TO-p53 and clones with doxycyline (Dox)-inducible expression of p53 were selected (MiaPaCa-2-TREx-p53). Dox treatment of MiaPaCa-2-TREx-p53 in vitro reduced proliferation to 11% of control. Cell cycle analyses revealed a pronounced accumulation of cells in the G1-phase upon Dox-treatment, which was accompanied by a prominent induction of p21, suggesting an induction of functionally competent p53 had occurred. To examine the consequences of p53 induction in vivo, MiaPaCa-2-TREx-p53 were orthotopically implanted into the pancreas of nude mice. The mice were randomly assigned to treatment and control groups and animals in the treatment groups received Dox in the drinking water. When treatment was started immediately after implantation, p53 induction resulted in 90% decrease of primary tumor mass at 4 weeks. Similarly, primary tumor size was reduced when Dox treatment was started after 4 weeks in already established tumors. Tumor vascularization was then evaluated based on Micro vessel density (MVD) and lymph vessel density (LVD), as determined by CD31 and Lyve-1 reactivity in immunohistochemistry (IHC). Both MVD and LVD were increased in tumors from animals with early p53 induction. Tumor LVD was also increased when p53 induction occurred in established tumors. Despite their smaller size, tumors from Dox treated- and control animals metastasized to lymph nodes with comparable frequency as judged by IHC detection of Human Cytokeratin. Taken together, the data obtained in the orthotopic model suggest divergent effects of p53 on pancreatic cancer primary tumor growth and metastasis. Apart from reducing primary tumor mass, p53 may contribute to metastatic spread via stimulation of lymphangiogenesis.