A Vitamin D Analogue Inhibits Colonic Carcinogenesis in the AOM/DSS Model
Background The azoxymethane (AOM) model recapitulates many features of human colon cancer, lacking an inflammatory component. Dextran sulfate sodium (DSS) induces colitis and promotes AOM-induced colon cancer in mice. Vitamin D analogues are anti-inflammatory and chemopreventive in models of colon c...
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Published in | The Journal of surgical research Vol. 142; no. 2; pp. 239 - 245 |
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Main Authors | , , , , , , , , , , , , |
Format | Journal Article Conference Proceeding |
Language | English |
Published |
New York, NY
Elsevier Inc
01.10.2007
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | Background The azoxymethane (AOM) model recapitulates many features of human colon cancer, lacking an inflammatory component. Dextran sulfate sodium (DSS) induces colitis and promotes AOM-induced colon cancer in mice. Vitamin D analogues are anti-inflammatory and chemopreventive in models of colon cancer. Our aim was to evaluate the anti-inflammatory and chemopreventive efficacy of the vitamin D analogue Ro26-2198 in the AOM/DSS model and in vitro in HCA-7 colon cancer cells. Materials and methods A/J mice received Ro26-2198 (0.01 μg/kg body wt/day × 28 days) or vehicle by mini-osmotic pump. Animals were treated with a single dose of AOM (5 mg/kg body wt) or vehicle 1 week after pump insertion. Mice received 3% DSS or water × 7 days beginning week 3. Animals were sacrificed after 8 weeks and colon segments were fixed in formalin or flash-frozen. Hematoxylin and eosin colonic sections were examined for dysplasia and colonic lysates were assessed for c-Myc, cyclooxygenase 2, and phospho-(active) extracellular signal regulated kinase (ERK) by Western blotting. For in vitro studies, HCA-7 cells were treated with Ro26-2198 followed by interleukin-1beta (IL-1β). Proliferation was measured by WST-1 assay. Results Ro26-2198 delayed the onset of clinical colitis. Several dysplastic foci were present in the AOM/DSS group; none were found in the Ro26-2198 group. Compared with control, AOM/DSS significantly increased c-Myc (15-fold), cyclooxygenase 2 (COX-2) (2.5-fold), and pERK (10-fold), and Ro26-2198 abolished these increases. In vitro , Ro26-2198 inhibited IL-1β-induced ERK activation and COX-2 induction and decreased HCA-7 cell proliferation. Conclusions Ro26-2198 inhibited proliferative (ERK, c-Myc) and pro-inflammatory (COX-2) signals and progression to dysplasia, suggesting chemopreventive efficacy in this model of colitis-associated carcinogenesis. |
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ISSN: | 0022-4804 1095-8673 |
DOI: | 10.1016/j.jss.2007.02.038 |