title: Targeting MEK is effective chemoprevention of hepatocellular carcinoma in TGF-alpha-transgenic mice.
abstract: Hepatocellular carcinoma (HCC) causes 600,000 mortalities per year worldwide. Previous studies from our lab provide evidence for altered mitogen-activated protein kinase and extracellular signal-regulated kinase kinase (MEK) signaling in HCC pathogenesis. We hypothesized that pharmacologic targeting of MEK may prevent HCC. Transforming growth factor-alpha-transgenic mice (CD1-MT42) exposed to diethylnitrosamine were randomized to 20 (trial I) or 35 (trial II) weeks of MEK inhibitor PD0325901 (1, 10 mg/kg) or control via orogastric gavage. Ten HCC (44%) formed in trial I controls versus 0 in treatment arms (p<0.05). Fourteen HCC (50%) formed in trial II controls versus 1 (9%) in treatment arms (p<0.05). Mean HCC volume was 578 mm3 in control versus 46 mm3 in the single tumor formed in trial II. In trial I, foci of altered hepatocytes (FAH) formed in 78% of control versus 40% and 0% (1 and 10 mg/kg PD0325901) in treatment arms (p<0.05). In trial II, incidence of FAH was 80% in control versus 20% and 50% (1 and 10 mg/kg PD0325901) in treatment arms (p<0.05). Hepatocyte expression of phosphorylated extracellular signal-regulated kinase dose-dependently decreased in trial I but remained the same in trial II. Control and treated HCC demonstrated similar proliferation rates, but apoptosis appeared increased with treatment. MEK targeting is effective HCC chemoprevention, perhaps by lowering the apoptotic threshold.
authors.affiliation: Department of Surgery, Indiana University School of Medicine, 1044 W Walnut St R4-039, Indianapolis, IN 46202, USA.
authors.forename: Sabrina C
authors.initials: SC
authors.lastname: Wentz
authors.forename: Huangbing
authors.initials: H
authors.lastname: Wu
authors.forename: Michele T
authors.initials: MT
authors.lastname: Yip-Schneider
authors.forename: Matthew
authors.initials: M
authors.lastname: Hennig
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Klein
authors.forename: Judith
authors.initials: J
authors.lastname: Sebolt-Leopold
authors.forename: C Max
authors.initials: CM
authors.lastname: Schmidt
mesh_terms: D000477:Alkylating Agents / Q000633:toxicity; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001549:Benzamides / Q000008:administration & dosage / Q000627:therapeutic use*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D049109:Cell Proliferation / Q000187:drug effects; D018890:Chemoprevention / Q000379:methods*; D004052:Diethylnitrosamine / Q000633:toxicity; D004159:Diphenylamine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005500:Follow-Up Studies; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008114:Liver Neoplasms, Experimental / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D051379:Mice; D008822:Mice, Transgenic; D016211:Transforming Growth Factor alpha / Q000378:metabolism*
chemical_list: D000477:Alkylating Agents; D001549:Benzamides; D019394:Ki-67 Antigen; D016211:Transforming Growth Factor alpha; D004052:Diethylnitrosamine; C506614:mirdametinib; D004159:Diphenylamine; D048049:Extracellular Signal-Regulated MAP Kinases