Poorer outcome in stromal HIF-2 alpha- and CA9-positive colorectal adenocarcinomas is associated with wild-type TP53 but not with BNIP3 promoter hypermethylation or apoptosis

Stromal expression of hypoxia inducible factor 2 alpha (HIF-2 alpha) and carbonic anhydrase 9 (CA9) are associated with a poorer prognosis in colorectal cancer (CRC). Tumour cell death, regulated by a hypoxic stromal microenvironment, could be of importance in this respect. Therefore, we correlated...

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Bibliographic Details
Published in:British journal of cancer 2008-09, Vol.99 (5), p.727-733
Main Authors: Cleven, A H G, Wouters, B G, Schutte, B, Spiertz, A J G, van Engeland, M, de Bruïne, A P
Format: Article
Language:English
Subjects:
Adenocarcinoma - genetics
Adenocarcinoma - metabolism
Adenocarcinoma - pathology
Antigens, Neoplasm - metabolism
Apoptosis
Basic Helix-Loop-Helix Transcription Factors - metabolism
Carbonic Anhydrase IX
Carbonic Anhydrases - metabolism
Clinical Study
Colorectal Neoplasms - genetics
Colorectal Neoplasms - metabolism
Colorectal Neoplasms - pathology
DNA Methylation
Genes, p53
Humans
Immunohistochemistry
Membrane Proteins - genetics
Mutation
Promoter Regions, Genetic
Prospective Studies
Proto-Oncogene Proteins - genetics
Stromal Cells - metabolism
Survival Analysis
Treatment Outcome
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Summary:Stromal expression of hypoxia inducible factor 2 alpha (HIF-2 alpha) and carbonic anhydrase 9 (CA9) are associated with a poorer prognosis in colorectal cancer (CRC). Tumour cell death, regulated by a hypoxic stromal microenvironment, could be of importance in this respect. Therefore, we correlated apoptosis, TP53 mutational status and BNIP3 promoter hypermethylation of CRC cells with HIF-2 alpha- and CA9-related poor outcome. In a series of 195 CRCs, TP53 mutations in exons 5-8 were analysed by direct sequencing, and promoter hypermethylation of BNIP3 was determined by methylation-specific PCR. Expressions of HIF-2 alpha, CA9, p53, BNIP3 and M30 were analysed immunohistochemically. Poorer survival of HIF-2 alpha and CA9 stromal-positive CRCs was associated with wild-type TP53 (P=0.001 and P=0.0391), but not with BNIP3 methylation. Furthermore, apoptotic levels were independent of the TP53 status, but lower in unmethylated BNIP3 CRCs (P=0.004). It appears that wild-type TP53 in CRC cells favours the progression of tumours expressing markers for hypoxia in their stroma, rather than in the epithelial compartment. Preserved BNIP3 function in CRC cells lowers apoptosis, and may thus be involved in alternative cell death pathways, such as autophagic cell death. However, BNIP3 silencing in tumour cells does not impact on hypoxia-driven poorer prognosis. These results suggest that the biology of CRC cells can be modified by alterations in the tumour microenvironment under conditions of tumour hypoxia.
ISSN:0007-0920
1532-1827
DOI:10.1038/sj.bjc.6604547