Urolithin A gains in antiproliferative capacity by reducing the glycolytic potential via the p53/TIGAR axis in colon cancer cells

Polyphenols have shown promising bioactivity in experimental in vitro and in vivo models for cancer chemoprevention. However, consumed orally, they are often transformed by gut microbes into new active principles with so far incompletely deciphered molecular mechanisms. Here, enterolacton, S-equol and urolithin A as representatives of metabolites of lignans, isoflavones and ellagitannins, respectively, were examined for their impact on HCT116 colon cancer cell growth, cooperativity with oxaliplatin and p53 dependency in vitro. Whereas enterolacton and S-equol (≤60 µM) did not elicit growth inhibition or positive cooperativity with oxaliplatin, urolithin A showed an IC(50) value of 19 µM (72 h) and synergism with oxaliplatin. Urolithin A induced p53 stabilization and p53 target gene expression, and absence of p53 significantly dampened the antiproliferative effect of urolithin A (IC(50)(p53−/−) = 38 µM). P53 was dispensable for the G(2)/M arrest in HCT116 cells but required for induction of a senescence-like phenotype upon long-term exposure and for the observed synergism with oxaliplatin. Moreover, extracellular flux analyses and knockdown approaches uncovered a reduced glycolytic potential via the p53/TIGAR axis which was linked to the higher susceptibility of wildtype cells to urolithin A. Overall, the p53 status turned out to be an important determinant for the potential benefit of dietary ellagitannins in cancer chemoprevention or use in adjuvant therapy.