The dicarbonyl electrophile scavenger 2-hydroxybenzylamine (2-HOBA)
prevents colorectal carcinogenesis and reduces tumor growth
Abstract
Background and Purpose: Colorectal cancer (CRC) is a major health
problem worldwide. Dicarbonyl electrophiles, such as iso-levuglandins
(isoLGs), are generated from lipid peroxidation and form covalent
adducts with amine-containing macromolecules. We have shown high levels
of adducts of isoLGs in colonic epithelial cells from patients with CRC.
We thus investigated the role of these reactive aldehydes on colon
cancer development. Experimental Approach: We investigated the effect of
oral treatment with 2-hydroxybenzylamine (2-HOBA), a natural compound
derived from buckwheat seeds that acts as a potent scavenger of
electrophiles, on colon carcinogenesis using the azoxymethane-dextran
sulfate sodium model of colitis-associated carcinogenesis and mice with
epithelial-specific deletion of the adenomatous polyposis coli gene, as
a model of sporadic cancer. We also tested 2-HOBA in a murine xenograft
of human HCT116 CRC cells implanted into the flank of nude mice. Key
Results: 2-HOBA is bioavailable in the colon of mice after
supplementation in the drinking water and does affect the colonic
microbiome. However, it reduced the level of isoLG adducts to lysine as
well as tumorigenesis in both models of CRC. In parallel, we found that
NRF2 activation and signaling was decreased in the colon of
2-HOBA-treated mice. Last, the growth of human tumors is significantly
attenuated by 2-HOBA supplementation. Conclusion and Implications:
2-HOBA, which has been shown to be safe in humans, reduces colon
tumorigenesis and growth of tumor cells in three distinct models of CRC.
Thus, 2-HOBA represents a promising natural compound for the prevention
and treatment of CRC.