The Prevention of a High Dose of Vitamin D or Its Combination with Sulforaphane on Intestinal Inflammation and Tumorigenesis in Apc1638N Mice Fed a High-Fat Diet

Abstract

Scope: The previous study shows that obesity-promoted inflammation is responsible for the activation of the intestinal tumorigenic Wnt-signaling. The present study aims to test a dietary strategy, dietary supplementation with a high dose of vitamin D (VD) or its combination with sulforaphane (SFN) to inhibit intestinal inflammation and obesity-associated tumorigenesis.

Methods and results: Apc^1638N mice are randomly divided into four groups: LF, a low-fat diet (10 kcal% fat) with 200 IU VD; HF, a high-fat diet (60 kcal% fat) with 200 IU VD; HFD, a high-fat diet with 5000 IU VD; and HFDS, a high-fat diet plus 5000 IU VD and 0.23 g SFN per ≈4000 kcal. VD administration decreased tumor incidence and size, and the co-administration with SFN (HFDS) magnified the effects. Inflammation and Wnt-signaling are suppressed by VD. The addition of SFN decreased the activity of histone deacetylase (HDAC) and increased autophagy.

Conclusion: The administration of VD, at 5000 IU level, exerts an anti-inflammatory property and leads to suppressed intestinal Wnt-signaling and tumorigenesis in obese mice. The molecular function of SFN on a high dose of VD supplementation, although displayed on the inhibition of HDAC and the activation of autophagy, needs further investigation.

Keywords: colorectal cancer; inflammation; obesity; sulforaphane; vitamin D.