Oral administration of the anti-proliferative substance taurolidine has no impact on dextran sulfate sodium induced colitis-associated carcinogenesis in mice

Abstract

Background: New chemopreventive strategies for ulcerative colitis (UC)-associated dysplasia and cancer have to be evaluated. Taurolidine (TRD) has anti-inflammatory, anti-proliferative and anti-neoplastic properties with almost absent toxicity. The aim of the study was to determine whether TRD decreases dysplasia in the well-characterized Dextran Sulfate Sodium - Azoxymethane (DSS-AOM) animal model for UC-associated carcinogenesis.

Material and methods: The DSS-AOM model of carcinogenesis was induced in female inbred C57BL/6 mice. Half of the mice were treated with TRD, the other served as control. After 100 days macroscopic, histological and immunhistochemical (beta-Catenin, E-Cadherin, SOX9, Ki-67, Cyclin-D1) examination of the colon was performed.

Results: Incidence, multiplicity, grading and growth pattern of adenomas did not differ significantly between TRD and control group. In all animals, inflammatory changes were absent. Immunhistochemistry revealed increased expression of Ki-67, beta-catenin, SOX9 and Cyclin-D1 in adenomas compared to normal mucosa - without significant difference between TRD and control treatment.

Conclusion: Oral administration of TRD has no impact on DSS-induced colitis-associated carcinogenesis. However, SOX9 and Cyclin-D1 representing key members of the Wnt pathway have not yet been described in the DSS-AOM model of carcinogenesis - underlining the importance of this oncogenic pathway in this setting.

Keywords: C57BL6 mice; Carcinogenesis; Dextran Sulfate Sodium; TRD; Taurolidin; Taurolin; experimental colitis; inflammatory bowel disease.

Figure 1

Disease Activity Index (DAI) of mice subjected to the DSSAOM (Dextran Sulfate Sodium - Azoxymethane) model of carcinogenesis after treatment with 0.2% Taurolidine (TRD) during DSS-free intervals compared to control treatment with water (H₂O) (each n = 9). There was a tri-phasic colitis with peak DAI values at the end of each DSS treatment interval (i.e. Day 12, 22 and 32, respectively) without any significant differences between the TRD group (TRD 0.2%) and the control group (H₂O) (repeated measures ANOVA over all time points). After 100 days, survival was 100% in both groups.

Figure 2

Representative histological Hematoxylin and Eosin (H and E) staining of normal colonic mucosa (A, C) and adenoma (B, D) in mice subjected to the DSS-AOM (Dextran Sulfate Sodium - Azoxymethane) model of carcinogenesis and treated with Taurolidine (TRD) 0.2% or drinking water as control (H₂O). A+C: normal colonic mucosa with regular crypt architecture; B+D: tubular adenoma with mild dysplasia (low grade) (×200 magnification). No difference between TRD and control treatment

Figure 3

Immunoreactivity scores (IRS) for Ki-67 (a), Cyclin-D1 (b), SOX9 (c), E-cadherin (d) as well as cytoplasmatic (e) and membranous β-catenin (f) in colonic adenoma and normal colonic mucosa of mice subjected to the DSS-AOM model of carcinogenesis and treated with Taurolidine (TRD) and water in the control group (H₂O). Bars indicate mean ± SEM, statistical analysis was carried out by Kruskal-Wallis test and Dunn's Multiple Comparison test (*P≤0.05; **P≤0.01; P***≤0.001)

Figure 4

Representative immunhistochemistry staining of Ki-67, Cyclin-D1, SOX9 and β-catenin of normal colonic mucosa (left side) and adenoma (right side) in mice subjected to the DSS-AOM (Dextran Sulfate Sodium - Azoxymethane) model of carcinogenesis without treatment (control group) (x200 magnification)