3-8-dihydroxy-6h-dibenzo(b-d)pyran-6-one and Urinary-Bladder-Neoplasms

Ellagitannins have been gaining attention as potential anticancer molecules. However, the low bioavailability of ellagitannins and their extensive metabolization in the gastrointestinal tract into ellagic acid and urolithins suggest that the health benefits of consuming ellagitannins rely on the direct effects of their metabolites. Recently, chemopreventive and chemotherapeutic activities were ascribed to urolithins. Nonetheless, there is still a need to screen and evaluate the selectivity of these molecules and to elucidate their cellular mechanisms of action. Therefore, this work focused on the antiproliferative effects of urolithins A, B and C and ellagic acid on different human tumor cell lines. The evaluation of cell viability and the determination of the half-maximal inhibitory concentrations indicated that the sensitivity to the studied urolithins varied markedly between the different cell lines, with the bladder cancer cells (UMUC3) being the most susceptible. In UMUC3 cells, urolithin A was the most active molecule, promoting cell cycle arrest at the G2/M checkpoint, increasing apoptotic cell death and inhibiting PI3K/Akt and MAPK signaling. Overall, the present study emphasizes the chemopreventive/chemotherapeutic potential of urolithins, highlighting the stronger effects of urolithin A and its potential to target transitional bladder cancer cells.

Topics: Apoptosis; Cell Cycle Checkpoints; Cell Proliferation; Coumarins; Ellagic Acid; Humans; Signal Transduction; Tumor Cells, Cultured; Urinary Bladder Neoplasms

Urolithins were the metabolites of ellagic acid by intestinal flora in gastrointestinal tract. In previous research, it was found that urolithins could mainly inhibit prostate cancer and colon cancer cell growth. However, there is no report about bladder cancer therapy of urolithins. In this paper, three urolithin-type compounds (urolithin A, urolithin B, 8-OMe-urolithin A) and ellagic acid were evaluated for antiproliferative activity in vitro against human bladder cancer cell lines T24. The IC₅₀ values for T24 cell inhibition were 43.9, 35.2, 46.3 and 33.7 μM for urolithin A, urolithin B, 8-OMe-urolithin A and ellagic acid, respectively. After the administration of urolithins and ellagic acid, we found these compounds could increase mRNA and protein expression of Phospho-p38 MAPK, and decrease mRNA and protein expression of MEKK1 and Phospho-c-Jun in T24 cells. Caspase-3 was also activated and PPAR-γ protein expression increased in drug-induced apoptosis. And what's more, the antioxidant assay afforded by three urolithins and EA treatments were associated with decreases in the intracellular ROS and MDA levels, and increased SOD activity in H₂O₂-treated T24 cells. The results suggested that these compounds could inhibit cell proliferation by p38-MAPK and/or c-Jun medicated caspase-3 activation and reduce the oxidative stress status in bladder cancer.

Topics: Antineoplastic Agents, Phytogenic; Antioxidants; Apoptosis; Caspase 3; Cell Line, Tumor; Cell Proliferation; Colon; Coumarins; Ellagic Acid; Enterobacteriaceae; Gene Expression Regulation, Neoplastic; Humans; Inhibitory Concentration 50; Lipid Peroxidation; MAP Kinase Signaling System; Methylation; Neoplasm Proteins; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; PPAR gamma; Reactive Oxygen Species; Urinary Bladder Neoplasms