title: Inhibin/activin expression in human and rodent liver: subunits α and βB as new players in human hepatocellular carcinoma?
abstract: BACKGROUND
  Activins and inhibins belong to the TGFβ-superfamily, which controls cell proliferation and differentiation in many organs. Activin A, the dimer of inhibin βA subunit, acts strongly anti-proliferative in hepatocytes. Little is known on the other activin/inhibin subunits in human liver and hepatocellular carcinoma (HCC).
  
  
  METHODS
  We studied the expression of the complete inhibin family α, βA, βB, βC, βE in normal liver, tumour-adjacent and HCC tissue, 12 additional organs and rodent liver. A total of 16 HCC and 10 disease-free livers were analysed. Expression of inhibin subunits was determined by qRT-PCR, normalised to RNA input and by geNorm algorithm, and confirmed by immunohistochemistry.
  
  
  RESULTS
  Remarkably, βA expression was not decreased in HCC. Similarly, βC and βE exhibited no major changes. In contrast, inhibin α, barely detectable in normal liver, was strongly increased in tumour-adjacent liver and dramatically enhanced in HCC. βB was strongly enhanced in some HCC. At variance with human liver, rodent liver showed higher inhibin α and βC expression, but βA was somewhat, and βB dramatically lower.
  
  
  CONCLUSIONS
  Upregulation of inhibin α - and possibly of βB - may shield HCC cells from anti-proliferative effects of activin A. Dramatic variations between humans and rodents may reflect different functions of some inhibins/activins.
authors.affiliation: Research Unit Chemical Safety and Cancer Prevention, Department Institute of Cancer Research, Clinics of Internal Medicine I, Medical University of Vienna, Borschkegasse 8A, Vienna 1090, Austria.
authors.forename: K
authors.initials: K
authors.lastname: Frost
authors.forename: K
authors.initials: K
authors.lastname: Seir
authors.forename: A
authors.initials: A
authors.lastname: Lackner
authors.forename: M
authors.initials: M
authors.lastname: Grusch
authors.forename: B
authors.initials: B
authors.lastname: Grasl-Kraupp
authors.forename: R
authors.initials: R
authors.lastname: Schulte-Hermann
authors.forename: C
authors.initials: C
authors.lastname: Rodgarkia-Dara
mesh_terms: D028341:Activins / Q000235:genetics* / Q000378:metabolism; D000328:Adult; D000368:Aged; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007265:Inhibins / Q000235:genetics* / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008113:Liver Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012377:Rodentia / Q000235:genetics* / Q000378:metabolism
chemical_list: D021122:Protein Subunits; D028341:Activins; D007265:Inhibins