title: Potentiation of the antitumor effects of both selective cyclooxygenase-1 and cyclooxygenase-2 inhibitors in human hepatic cancer cells by inhibition of the MEK/ERK pathway.
abstract: The molecular mechanisms behind the anti-neoplastic effects of non-steroidal anti-inflammatory drugs (NSAIDs) are not completely understood and cannot be explained by the inhibition of the cyclooxygenase (COX) enzymes COX-1 and COX-2 alone. We previously reported that both the selective COX-1 inhibitor SC-560 and the selective COX-2 inhibitor CAY10404 exhibit anti-tumor effects in human hepatoma cells. NSAID inhibitors have many COX-independent actions and, among others, the mitogen-activated protein kinase (MAPK) pathways are targets for NSAIDs. Here, we examined the role of MEK/ERK1/2 signaling in the anti-neoplastic effects of both selective COX-1 and COX-2 inhibitors in two human hepatoma cell lines. Treatment of hepatoma cells with the selective COX-1 inhibitor SC-560, as well as with the selective COX-2 inhibitor CAY10404, was associated with activation of ERK1/2 in a time- and dose-dependent manner. Treatment with COX-1 and COX-2 inhibitors in the presence of the selective MEK1/2 inhibitor U0126 effectively suppressed ERK1/2 activation and combinations of either SC-560 or CAY10404 with U0126 resulted in synergistic effects on cell growth inhibition and induction of apoptosis. In HuH-6 hepatoma cells the combination-induced apoptosis was associated with caspase-9 and -3 activation, PARP cleavage, release of cytochrome c from the mitochondria into the cytosol and down-regulation of survivin and beta-catenin levels. In conclusion, our study showed that growth inhibitory concentrations of selective COX-1 and COX-2 inhibitors increased ERK1/2 phosphorylation in hepatoma cells, and that inhibition of the MEK/ERK signaling pathway potentiates the antitumor activity of both types of inhibitors. Therefore, our results provide preclinical support for a combined chemotherapeutic approach with selective NSAIDs and MEK inhibitors for the treatment of hepatocellular carcinoma.
authors.affiliation: Istituto di Biomedicina e Immunologia Molecolare Alberto Monroy, Consiglio Nazionale delle Ricerche, Palermo, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Cusimano
authors.forename: Daniela
authors.initials: D
authors.lastname: Foderà
authors.forename: Natale
authors.initials: N
authors.lastname: D'Alessandro
authors.forename: Nadia
authors.initials: N
authors.lastname: Lampiasi
authors.forename: Antonina
authors.initials: A
authors.lastname: Azzolina
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Montalto
authors.forename: Melchiorre
authors.initials: M
authors.lastname: Cervello
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002070:Butadienes / Q000494:pharmacology; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000201:enzymology; D020169:Caspases / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D051545:Cyclooxygenase 1 / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000737:chemistry* / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000627:therapeutic use*; D045304:Cytochromes c / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D006801:Humans; D007555:Isoxazoles / Q000627:therapeutic use; D008113:Liver Neoplasms / Q000188:drug therapy / Q000201:enzymology; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011720:Pyrazoles / Q000627:therapeutic use; D013450:Sulfones / Q000627:therapeutic use; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: C501048:3-(4-methylsulfonylphenyl)-4-phenyl-5-trifluoromethylisoxazole; D002070:Butadienes; D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D007555:Isoxazoles; D009570:Nitriles; D011720:Pyrazoles; C115461:SC 560; D013450:Sulfones; C113580:U 0126; D045304:Cytochromes c; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases; D020169:Caspases