1. ¹Vascular Biology Program, Department of Surgery, Children's Hospital and Harvard Medical School, Boston, MA, USA
2. ²Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
3. ³Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA, USA
4. ⁴Hokkaido University, Grad. School of Dental Medicine and Oral Pathology, Sapporo, Japan
5. ⁵Department of Pathology, Children's Hospital and Harvard Medical School, Boston, MA, USA

Correspondence: Dr M Klagsbrun, Vascular Biology Program, Department of Surgery, Children's Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA. E-mail: michael.klagsbrun@childrens.harvard.edu

Received 2 May 2008; Accepted 15 May 2008.

Abstract

Alterations in the tumour suppressor p53 have been reported in tumour-associated stromal cells; however, the consequence of these alterations has not been elucidated. We investigated p53 status and responses to p53-activating drugs using tumour-associated stromal cells from A375 melanoma and PC3 prostate carcinoma xenografts, and a spontaneous prostate tumour model (TRAMP). p53 accumulation after treatment with different p53-activating drugs was diminished in tumour-associated stromal cells compared to normal stromal cells. Tumour-associated stromal cells were also less sensitive to p53-activating drugs – this effect could be reproduced in normal stromal cells by p53 knockdown. Unlike normal stromal cells, tumour stromal cells failed to arrest in G₂ after etoposide treatment, failed to upregulate p53-inducible genes, and failed to undergo apoptosis after treatment with vincristine. The lower levels of p53 in tumour stromal cells accompanied abnormal karyotypes and multiple centrosomes. Impaired p53 function in tumour stroma might be related to genomic instability and could enable stromal cell survival in the destabilising tumour microenvironment.