Acquired deficiency of the peroxisomal enzyme enoyl-CoA hydratase/3-hydroxyacyl CoA dehydrogenase is a metabolic vulnerability in hepatoblastoma
Metabolic reprogramming provides transformed cells with proliferative and/or survival advantages. However, capitalizing on this therapeutically has been only moderately successful due to the relatively small magnitude of these differences and because cancers may re-program their metabolism to evade metabolic pathway inhibition. Mice lacking the peroxisomal bi-functional enzyme enoyl-CoA hydratase/3-hydroxyacyl CoA dehydrogenase (Ehhadh) and supplemented with the 12-carbon fatty acid lauric acid (C12) accumulate dodecanedioic acid (DDDA), a toxic C12 metabolite that causes hepatocyte necrosis and acute liver failure. In a murine model of pediatric hepatoblastoma (HB), down-regulation of Ehhadh also occurs in combination with a more general suppression of mitochondrial {beta}- and peroxisomal {omega}-fatty acid oxidation (FAO) pathways. HB-bearing mice provided with C12 and/or DDDA-supplemented diets survived significantly longer than those on standard diets. The tumors also developed massive necrosis in response to short-term DDDA supplementation. Reduced Ehhadh was noted in murine hepatocellular carcinomas (HCCs) and in substantial subsets of human cancers, including HCCs. Acquired DDDA resistance was not associated with Ehhadh re-expression but was associated with 129 transcript differences ~90% of which were down-regulated in DDDA-resistant tumors and ~two-thirds of which correlated with survival in several human cancers. These transcripts often encoded components of the extracellular matrix suggesting that DDDA resistance arises from its reduced intracellular transport. Our results demonstrate the feasibility of a metabolic intervention that is non-toxic, inexpensive and likely compatible with traditional therapies. C12 and/or DDDA-containing diets could potentially be used to supplement other treatments or as alternative therapeutic choices.