Journal Article

Characterization of a vitamin D receptor knockout mouse as a model of colorectal hyperproliferation and DNA damage

Enikö Kallay, Peter Pietschmann, Shinya Toyokuni, Erika Bajna, Philipp Hahn, Karl Mazzucco, Christian Bieglmayer, Shigeaki Kato and Heide S. Cross

in Carcinogenesis

Volume 22, issue 9, pages 1429-1435
Published in print September 2001 | ISSN: 0143-3334
Published online September 2001 | e-ISSN: 1460-2180 | DOI: http://dx.doi.org/10.1093/carcin/22.9.1429
Characterization of a vitamin D receptor knockout mouse as a model of colorectal hyperproliferation and DNA damage

More Like This

Show all results sharing this subject:

  • Clinical Cytogenetics and Molecular Genetics

GO

Show Summary Details

Preview

The vitamin D receptor knockout (VDR-KO) mouse presents with a skeletal phenotype typical for complete lack of genomic 1,25-dihydroxycholecalciferol effects. Our previous data from human colorectal tissue suggest that the steroid hormone and its receptor may have protective function against tumour progression. In order to investigate the relevance of the vitamin D system for pre-malignant site-directed changes in the colon, we characterized the amount and site-specific distribution of the VDR along the large intestine in wild-type (WT), heterozygote (HT) and KO mice. We also evaluated expression of proliferating cell nuclear antigen (PCNA), of cyclin D1 and the levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), a marker of oxidative stress. In colon ascendens, proliferative cells were dispersed all along the crypt and expression levels of all three markers were high in WT mice. A decrease of VDR expression did not affect expression significantly. In colon descendens, however, fewer proliferative cells were solely located in the lower third of the crypt, and an inverse relationship between VDR reduction, PCNA positivity and cyclin D1 expression was found in HT and KO mice. In parallel to enhanced proliferation a highly significant increase of 8-OHdG positivity occurred. Therefore, the sigmoid colon of VDR-KO mice, fed on an appropriate lactose/calcium-enriched diet to alleviate impaired calcium homeostasis-related phenotypic changes, is an excellent model for investigating induction and prevention of pre-malignant changes in one of the hotspots for human colorectal cancer incidence.

Keywords: HT, heterozygote; 8-OHdG, 8-hydroxy-2′-deoxyguanosine; PCNA, proliferating cell nuclear antigen; VDR-KO, vitamin D receptor knockout; WT, wild-type.

Journal Article.  5413 words.  Illustrated.

Subjects: Clinical Cytogenetics and Molecular Genetics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.