Reference SummarySong J, Cancer Res 2000 Oct 1;60(19):5434-40

Title

Effects of dietary folate on intestinal tumorigenesis in the apcMin mouse

Authors

Song J; Medline A; Mason JB; Gallinger S; Kim YI

Journal

Cancer Res

Volume

Issue

Year

2000

Pages

5434-40

Abstract

Dietary folate appears to be inversely related to colorectal cancer risk. This study investigated the effects of dietary intervention with folate or the development of intestinal polyps in Min (Apc +/-) mice. Weanling Mil mice were fed diets containing 0, 2 (basal requirement), 8, or 20 mg folate/kg diet. At 3 and 6 months of dietary intervention, 50% of the mice from each group were sacrificed, and the small intestine and colon were analyzed for polyps and aberrant crypt foci (ACF). Serum folate concentrations accurately reflected dietary folate levels (P < 0.001). At 3 months no significant difference in the average number of total small intestinal polyps was observed among the four groups. However, increasing dietary folate levels significantly reduced the number of ileal, but not duodenal or jejunal, polyps in a dose-dependent manner (P-trend = 0.001); folate supplementation at 20 mg/kg diet was associated with a 68-78% reduction in the number of ileal polyps compared with the other three diets (P < 0.007). The number of ileal polyps was inversely correlated with serum folate concentrations (P = 0.03). At 3 months, increasing dietary folate levels significantly decreased the number of colonic ACF in a dose-dependent manner (P = 0.05); the control and two folate supplemented diets significantly reduced the number of colonic ACF by 75 100% compared with the folate-deficient diet (P < 0.04). The number of colonic ACF was inversely correlated with serum folate concentration (P = 0.05). No significant difference in the number of colonic adenoma was observed among the four groups at 3 months. At 6 months, no significant differences in the average number of total small intestinal, duodenal, and jejunal polyps, colonic adenomas, and colonic ACF wer observed among the four groups. However, the folate-deficient diet had 62-76% lower number of ileal polyps compared with the control and two folate-supplemented diets (P < 0.003). Serum folate concentrations, but not dietary folate levels, were directly correlated with the number of ilea polyps (P = 0.006). These data suggest that dietary folate supplementation suppresses the development of ileal polyps and colonic ACF in this model However, at later time points, folate supplementation appears to have an opposite effect on ileal polyps. These data generally support the role of folate in intestinal tumorigenesis suggested in epidemiological studies and chemical carcinogen animal models. Notwithstanding the limitations associated with this model, these data suggest that the optimal timing and dose of folate intervention need to be determined for safe and effective folate chemoprevention.

Links

J:65027 – MGI References
11034085 – National Library of Medicine/PubMed

Strain Notes

Strain

Note

C57BL/6J-Apc^Min/+

Mice in all 4 treatment groups had similar growth curves. No premature deaths were observed.
Mice were bred at the Samuel Lunenfeld Research Institute, original breeding pairs were purchased from The Jackson Laboratory. Lifespan ~6 months.
Serum folate levels were elevated in a dose-dependent manner for the 2 and 8 mg folate/kg diet groups, while no further increase was seen in the 20 mg folate/kg diet group. These trends were observed at both timepoints.

Models
Strain	Model Name	Treatment Agent(s)	Organ Affected	Frequency
C57BL/6J-Apc^Min/+	Intestine - Large Intestine - Colon adenoma	folate-deficient	Intestine - Large Intestine - Colon	observed
C57BL/6J-Apc^Min/+	Intestine - Large Intestine - Colon adenoma		Intestine - Large Intestine - Colon	observed
C57BL/6J-Apc^Min/+	Intestine - Large Intestine - Colon adenoma	folate-supplemented	Intestine - Large Intestine - Colon	observed
C57BL/6J-Apc^Min/+	Intestine - Large Intestine - Colon foci - aberrant crypt (ACF)	folate-deficient	Intestine - Large Intestine - Colon	observed
C57BL/6J-Apc^Min/+	Intestine - Large Intestine - Colon foci - aberrant crypt (ACF)		Intestine - Large Intestine - Colon	observed
C57BL/6J-Apc^Min/+	Intestine - Large Intestine - Colon foci - aberrant crypt (ACF)	folate-supplemented	Intestine - Large Intestine - Colon	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine - Duodenum adenoma	folate-deficient	Intestine - Small Intestine - Duodenum	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine - Duodenum adenoma		Intestine - Small Intestine - Duodenum	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine - Duodenum adenoma	folate-supplemented	Intestine - Small Intestine - Duodenum	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine - Ileum adenoma	folate-deficient	Intestine - Small Intestine - Ileum	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine - Ileum adenoma		Intestine - Small Intestine - Ileum	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine - Ileum adenoma	folate-supplemented	Intestine - Small Intestine - Ileum	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine - Jejunum adenoma	folate-deficient	Intestine - Small Intestine - Jejunum	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine - Jejunum adenoma		Intestine - Small Intestine - Jejunum	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine - Jejunum adenoma	folate-supplemented	Intestine - Small Intestine - Jejunum	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine adenoma	folate-deficient	Intestine - Small Intestine	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine adenoma		Intestine - Small Intestine	observed
C57BL/6J-Apc^Min/+	Intestine - Small Intestine adenoma	folate-supplemented	Intestine - Small Intestine	observed