title: Proapoptotic and antiproliferative potential of selective cyclooxygenase-2 inhibitors in human liver tumor cells.
abstract: Recent studies have shown increased levels of cyclooxygenase-2 (COX-2) in a variety of human malignancies, including hepatocellular carcinoma (HCC), but so far it is unknown whether COX-2 contributes to the malignant growth and whether inhibition of COX-2 function modifies the malignant potential of liver tumors. COX-1 and COX-2 expression was determined in 4 liver tumor cell lines (Hep 3B, HuH-7, Hep G2, Sk-hep1) by Northern hybridization and Western immunoblot. The functional effects of the nonselective inhibitor sulindac sulfide and the COX-2 selective inhibitors SC-58635 and meloxicam were examined by 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazoliumbromide (MTT)-assays and BrdU uptake, morphology, and TUNEL analysis of apoptosis. Apoptosis regulating proteins were analyzed by Western immunoblot. COX-1 and COX-2 expression was demonstrable in all tested liver tumor cell lines. Sulindac sulfide (50 to 400 micromol/L), SC-58635 (6,25 to 400 micromol/L), and meloxicam (6.25 to 400 micromol/L) led to a significant time- and dose-dependent reduction of cell numbers of up to 80% (P <.05). At equimolar concentrations the effect was more pronounced when COX-2 was selectively blocked. COX-2 inhibition induced apoptosis and reduced tumor cell proliferation. Apoptosis after COX-2 inhibition with SC-58635 (50 micromol/L) was independent of BCL-2, BAX, and the phosphorylation status of AKT/PKB and BAD, but correlated with activation of caspase-9, caspase-3, and caspase-6. In conclusion, selective inhibition of COX-2 leads to a marked growth inhibition of human liver tumor cells, based on the induction of apoptosis and inhibition of proliferation and, thus, may offer therapeutic and preventive potential in human hepatocarcinogenesis.
authors.affiliation: Institute of Pathology, University of Cologne, Germany.
authors.forename: Michael André
authors.initials: MA
authors.lastname: Kern
authors.forename: Dominic
authors.initials: D
authors.lastname: Schubert
authors.forename: Dina
authors.initials: D
authors.lastname: Sahi
authors.forename: Mirja Mareike
authors.initials: MM
authors.lastname: Schöneweiss
authors.forename: Ilona
authors.initials: I
authors.lastname: Moll
authors.forename: Anke Maria
authors.initials: AM
authors.lastname: Haugg
authors.forename: Hans Peter
authors.initials: HP
authors.lastname: Dienes
authors.forename: Kai
authors.initials: K
authors.lastname: Breuhahn
authors.forename: Peter
authors.initials: P
authors.lastname: Schirmacher
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D006528:Carcinoma, Hepatocellular; D002352:Carrier Proteins / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D000068579:Celecoxib; D002455:Cell Division / Q000187:drug effects; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D008113:Liver Neoplasms; D000077239:Meloxicam; D008565:Membrane Proteins; D010766:Phosphorylation; D011451:Prostaglandin-Endoperoxide Synthases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011720:Pyrazoles; D013449:Sulfonamides / Q000494:pharmacology*; D013843:Thiazines / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000201:enzymology; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein
chemical_list: C494819:BAD protein, human; C494826:BAX protein, human; D002352:Carrier Proteins; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011720:Pyrazoles; D013449:Sulfonamides; D013843:Thiazines; D013844:Thiazoles; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D020169:Caspases; D000068579:Celecoxib; D000077239:Meloxicam