Effects of vandetanib on adenoma formation in a dextran sodium sulphate enhanced ApcMIN/+ mouse model

Abstract

The Apc(MIN/+) mouse is a well-characterised model of intestinal tumourigenesis in which animals develop macroscopically detectable adenomas. However, most of the adenomas are formed in the small intestine and resolution of events in the colon, the most relevant site for human disease, is limited. Inducing colitis with dextran sodium sulphate (DSS) can selectively enhance the development of lesions in the colon. We demonstrated that a DSS pre-treatment is well tolerated and effective at inducing colon adenomas in an Apc(MIN/+) mouse model. We then investigated the effect of inhibiting vascular endothelial growth factor (VEGFR)- and epidermal growth factor receptor (EGFR)-dependent signalling pathways on the development of adenomas induced in DSS-pretreated (DSS/Apc(MIN/+)) or non-DSS-pretreated (Apc(MIN/+)) mice using vandetanib (ZD6474), a potent and selective inhibitor of VEGFR and EGFR tyrosine kinase activity. Eight-week old Apc(MIN/+) mice were given either drinking water or 1.8% DSS and then vandetanib (ZD6474) (50 mg/kg/day) or vehicle by oral gavage for 28 days and sacrificed 24 h after the last dose and assessed for adenoma formation in the intestines. DSS pre-treatment was well tolerated and significantly enhanced formation of adenomas in the colon of control Apc(MIN/+) mice. Vandetanib treatment significantly reduced adenoma formation in the small intestine by 68% (P=0.001) and the colon by 77% (from 13.8 to 3.1, P=0.01) of DSS-pretreated Apc(MIN/+) mice. In the Apc(MIN/+) group, vandetanib also reduced the mean number of adenomas in the small intestine by 76% (P<0.001) and in the colon by 60% (from 3.9 to 1.5, P=0.1). DSS-pre-treatment increased the resolution of the model, allowing us to confirm statistically significant effects of vandetanib on the development and growth of colon adenomas in the Apc(MIN/+) mouse. Moreover these preclinical data provide a rationale for studying the effects of vandetanib in early stages of intestinal cancer in the clinic.

Apurinic/apyrimidinic endonuclease 1, the sensitive marker for DNA deterioration in dextran sulfate sodium-induced acute colitis

“…[3][4][5][6] The information available regarding the molecular and genetic pathways that result in colorectal cancer, such as tumor suppressor genes, DNA mismatch repair (MMR) genes and proto-oncogenes, has increased markedly. The specific contributing mutations in genes such as adenomatous polyposis coli (APC) [7][8][9][10][11] and MMR 8, [12][13][14][15][16][17][18] have been investigated intensively. Mutations or deficiencies in APC and MMR contribute significantly to the development of age-related or familial colonic neoplasia and sporadic or mucosal damage-related neoplasia, respectively.…”

Inhibition of Aurora-B kinase activity confers antitumor efficacy in preclinical mouse models of early and advanced gastrointestinal neoplasia

“…When the whole SB was considered (SB All) barasertib reduced the mean number of adenomas by 39% from 52.31±6.18 to 31.87±5.64 (P<0.05); Table II. There were much fewer adenomas in the colon than in the SB, due to the lower incidence of adenomas occurring in the colon in this model (22). Although a similar reduction in the number of adenomas in the colon (38%) was seen in barasertib versus vehicle-treated mice, this did not reach statistical significance (Table II).…”

“…The SB was divided into three equal sections: proximal (SB1), middle (SB2) and distal (SB3). These sections and the colon were dissected longitudinally using a recently described cutting guide (22) and spread onto filter paper before being fixed in Carnoy's fluid for 1 h and stored in 70% ethanol until analysis. Macroscopic adenoma quantification was carried out using a dissecting microscope as described previously (23) to assess the number, size and overall tumor burden.…”

Analysis of mutations in tumor and normal adjacent tissue via fluorescence detection

“…Mice exposed to 1% DSS did not show a statistically significant difference in tumor burden in the ileum after 2 weeks (Figure S2a), which is consistent with previous studies (Ohtsuka and Sanderson, 2003; Tanaka et al ., 2006). It is noteworthy that in several studies, it was observed that DSS also induced tumorigenesis in the ileum (Cooper et al ., 2001; Tanaka et al ., 2006; Alferez et al ., 2010; Tanaka, 2012), however these studies utilized higher concentrations of DSS and a longer timepoint, producing a stronger effect (Tanaka et al ., 2006; Alferez et al ., 2010). In contrast to the ileum, we observed a dramatic increase in tumors in the colon (Figure 2e), and these were primarily concentrated in the distal region (which is consistent with previous studies of DSS‐induced colonic inflammation) (Kitajima et al ., 2000; Seamons et al ., 2013; Biton et al ., 2018).…”