title: Fenofibrate suppresses growth of the human hepatocellular carcinoma cell via PPARα-independent mechanisms.
abstract: Fenofibrate, a peroxisome proliferator-activated receptor (PPAR) α agonist, is a hypolipidemic drug. Although several studies have explored the fenofibrate-induced antiproliferative effect in cultured human cells, it is not clear which role PPARα plays in this antiproliferative effect. Therefore, we investigated the antiproliferative mechanism of fenofibrate in Huh7 (human hepatoma cell line). Cell viability was measured by the WST-8 assay and cell proliferation was assessed using the BrdU incorporation assay. The cell cycle was analyzed by flow cytometry. The cyclins, tumor suppressor proteins and regulators of the AKT signaling pathway were analyzed by immunoblotting. Using flow cytometry, we showed that fenofibrate blocks entry into the S phase of the cell cycle. We certified that this G1 arrest is caused by the reduction of cyclin A and E2F1 and the accumulation of the cyclin-dependent kinase inhibitor p27. Interestingly, the antiproliferative effect of fenofibrate was not affected by the PPARα antagonist (GW6471) or by PPARα-specific siRNA. These results suggest that fenofibrate suppresses Huh7 cell growth through a PPARα independent mechanism. Furthermore, we showed that treatment of Huh7 cells with fenofibrate leads to suppression of AKT phosphorylation. We also found for the first time that fenofibrate increased the C-terminal modulator protein (CTMP), which inhibits AKT phosphorylation. Our data suggest that fenofibrate inhibits the proliferation of Huh7 cells by blocking Akt activation, and that CTMP is one of the key players for this antiproliferative property of fenofibrate in Huh7 cells.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Yamasaki
authors.forename: Natsuko
authors.initials: N
authors.lastname: Kawabe
authors.forename: Hitomi
authors.initials: H
authors.lastname: Nakamura
authors.forename: Keisuke
authors.initials: K
authors.lastname: Tachibana
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishimoto
authors.forename: Toshiya
authors.initials: T
authors.lastname: Tanaka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Aburatani
authors.forename: Juro
authors.initials: J
authors.lastname: Sakai
authors.forename: Takao
authors.initials: T
authors.lastname: Hamakubo
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Kodama
authors.forename: Takefumi
authors.initials: T
authors.lastname: Doi
mesh_terms: D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D019925:Cyclin A / Q000037:antagonists & inhibitors* / Q000378:metabolism; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000096:biosynthesis; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D050687:E2F1 Transcription Factor / Q000378:metabolism; D011345:Fenofibrate / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D015151:Immunoblotting; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D010080:Oxazoles / Q000494:pharmacology; D047493:PPAR alpha / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors*; D034622:RNA Interference; D034741:RNA, Small Interfering; D015398:Signal Transduction / Q000187:drug effects; D025521:Tumor Suppressor Proteins / Q000032:analysis; D014443:Tyrosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000099270:Y-Family DNA Polymerases
chemical_list: D019925:Cyclin A; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004259:DNA-Directed DNA Polymerase; D050687:E2F1 Transcription Factor; D011345:Fenofibrate; D010080:Oxazoles; D047493:PPAR alpha; D051057:Proto-Oncogene Proteins c-akt; D034741:RNA, Small Interfering; D025521:Tumor Suppressor Proteins; D014443:Tyrosine; C493753:E2F1 protein, human; C449302:GW 6471; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases