Cancer-preventive Properties of an Anthocyanin-enriched Sweet Potato in the APCMIN Mouse Model

BACKGROUND: Anthocyanin-rich foods and preparations have been reported to reduce the risk of life-style related diseases, including cancer. The SL222 sweet potato, a purple-fleshed cultivar developed in New Zealand, accumulates high levels of anthocyanins in its storage root. METHODS: We examined the chemopreventative properties of the SL222 sweet potato in the C57BL/6J-APC(MIN/+) (APC(MIN)) mouse, a genetic model of colorectal cancer. APC(MIN) and C57BL/6J wild-type mice (n=160) were divided into four feeding groups consuming diets containing 10% SL222 sweet potato flesh, 10% SL222 sweet potato skin, or 0.12% ARE (Anthocyanin rich-extract prepared from SL222 sweet potato at a concentration equivalent to the flesh-supplemented diet) or a control diet (AIN-76A) for 18 weeks. At 120 days of age, the mice were anaesthetised, and blood samples were collected before the mice were sacrificed. The intestines were used for adenoma enumeration. RESULTS: The SL222 sweet potato-supplemented diets reduced the adenoma number in the APC(MIN) mice. CONCLUSIONS: These data have significant implications for the use of this sweet potato variant in protection against colorectal cancer.

Secondary bile acid induced intestinal adenoma canceration and its effect on intestinal microflora in Apcmin/+ mice / 中华消化杂志

Objective To investigate secondary bile acid induced canceration process of intestinal adenoma and effects on intestinal microflora in Apcmin/+ mice.Methods Forty four-week-old mice (20 Apcmin/+mice and 20 wild-type C57BL/6J mice) were divided into four groups:wild-type control group (regular drinking water),wild-type deoxycholic acid (DOC) group (with 0.2 ％ DOC in drinking water),Apcmin/+ control group and Apcmin/+ DOC group.Fecal pellets of Apcmin/+ mice were collected at 0 week and 12 week after administration.The changes of intestinal microflora were analyzed by pyrosequencing.All mice were sacrificed after 12 weeks.The number,size and location of intestinal adenoma were observed.The pathological type of adenoma was evaluated after hematcxylin-eosin (HE) staining.Proliferating cell nuclear antigen (PCNA) was detected by immunohistochemistry.Cell apoptosis was determined by in situ terminal deoxynucleotidyl transferase mediated dUTP nick end labeling technique (TUNEL).Independent t test was used for the quantitative data comparison between two groups.Results No intestinal tumors were found in the wild-type mice.The total number of intestinal adenoma of Apcmin/+ DOC group significantly increased,compared with that of Apcmin/+ control group (57.00 ± 3.07 vs 21.50± 4.69,t=20.03,P＜0.01),the increase of the adenoma with maximum diameter between 1 to 2 mm was most significant (30.62± 7.73 vs 7.75 ± 4.59,t =8.04,P＜ 0.05),the rate of adenoma canceration also significantly increased compared with that of Apcmin/+ control group.The percentage of PCNA positive cells significantly increased compared with that of Apcmin/+ control group ((90.17 ± 2.14) ％ vs (41.97 ± 4.26) ％,t=31.97,P＜0.01).The percentage of cell apoptosis significantly declined ((1.40± 1.12) ％ vs (7.50 ± 0.65)％,t =14.90,P＜ 0.01).The diversity of intestinal flora of Apcmin/+ DOC group significantly decreased.The ratio of Firmicutes and Bacteroidetes significantly increased compared with control group (0.586 7±0.148 4 vs 0.387 3±0.013 6,t=2.36,P＜0.05).The number of pathogenic bacteria increased in Apcmin/+ DOC group and probiotics significantly decreased.Conclusion DOC can induce intestinal flora imbalance in Apcmin/+ mice and promote intestinal adenoma into adenocarcinoma through increasing tumor cell proliferation and inhibiting cell apoptosis.

Establishment of a transgenic heterozygous mouse model of ApcMin/+pre-cancerosis of colorectal cancer with p110δmutation / 中国病理生理杂志

[ABSTRACT]AIM:Toestablishatransgenicheterozygousmousemodelofprecancerouslesionsofcolorectal cancer with p110δmutation in the C57BL/6J background for serving the studies on colorectal cancer research mediated by p110δ.METHODS:The transgenic heterozygous mice were generated by crossing in p110δD910A/D910A mouse and ApcMin/+mouse, and the genotype was detected by PCR .Compared with ApcMin/+mice, transgenic heterozygous mice ( ApcMin/+;p110δD910A/D910A)were counted, and the number and size of intestine polyps were analyzed after methylene blue staining . The intestinal tissue structure was assessed by HE staining .RESULTS:The transgenic heterozygous mouse model of pre-cancerous lesions of colorectal cancer with p 110δmutation was established .The number and size of polyps in the transgenic heterozygous mice were declined .CONCLUSION: A transgenic heterozygous mouse model of precancerous lesions of colorectal cancer with p 110δmutation was successfully established .The initial phenotype of intestinal tumors in transgenic mice was observed .This model will greatly contribute to the related research of colorectal cancer in mice .

Inhibitory effects of calcium against intestinal cancer in human colon cancer cells and ApcMin/+ mice

The aim of the study was to investigate the inhibitory effects of calcium against intestinal cancer in vitro and in vivo. We first investigated the effects of calcium treatment in HCT116 and HT29 human colon cancer cells. At the concentration range of 0.8-2.4 mM, calcium significantly inhibited cell growth (by 9-29%), attachment (by 12-26%), invasion (by 15-31%), and migration (by 19-61%). An immunofluorescence microscope analysis showed that the treatment with calcium (1.6 mM) for 24 h increased plasma membrane beta-catenin but decreased nuclear beta-catenin levels in HT29 cells. We then investigated the effect of dietary calcium on intestinal tumorigenesis in ApcMin/+ mice. Mice received dietary treatment starting at 6 weeks of age for the consecutive 8 weeks. The basal control diet contained high-fat (20% mixed lipids by weight) and low-calcium (1.4 mg/g diet) to mimic the average Western diet, while the treatment diet contained an enriched level of calcium (5.2 mg calcium/g diet). The dietary calcium treatment decreased the total number of small intestinal tumors (by 31.4%; P or = 2 mm in diameter, showing a 75.6% inhibition in the small intestinal tumor multiplicity (P < 0.001). Immunohistochemical analysis showed significantly reduced nuclear staining of beta-catenin (expressed as nuclear positivity), but increased plasma membrane staining of beta-catenin, in the adenomas from the calcium-treated groups in comparison to those from the control group (P < 0.001). These results demonstrate intestinal cancer inhibitory effects of calcium both in human colon cancer cells and Apc Min/+ mice. The decreased beta-catenin nuclear localization caused by the calcium treatment may contribute to the inhibitory action.