title: X-linked inhibitor of apoptosis (XIAP) and XIAP-associated factor-1 expressions and their relationship to apoptosis in human hepatocellular carcinoma and non-cancerous liver tissues.
abstract: The X-linked inhibitor of apoptosis (XIAP) belongs to the inhibitor of apoptosis (IAP) family, and the action of XIAP is inhibited by XIAP-associated factor-1 (XAF1). In the present study, XIAP and XAF1 protein expressions and their relationship to apoptosis were investigated in hepatocellular carcinoma (HCC). We examined immunohistochemical expressions of XIAP and XAF1, and the number of apoptotic HCC cells in surgically resected tissues of 24 HCCs, consisting of 7 well-, 10 moderately and 7 poorly differentiated HCCs. As a result, XIAP and XAF1 expressions were identified in the cytoplasm of non-neoplastic and neoplastic hepatocytes. In the 24 HCCs, XIAP expression was not different according to the histological grade of HCC. In contrast, XAF1 expression was significantly lower in poorly differentiated than that in well- or moderately differentiated HCCs (P=0.001), or XIAP expression in poorly differentiated HCC (P<0.001). Apoptotic HCC cell number was significantly lower in poorly differentiated than that in well- or moderately differentiated HCCs (P<0.01). A significant relationship was observed between XAF1 expression and apoptotic cell number in HCC tissues. In conclusion, the present findings suggest that significantly low XAF1 expression, but not XIAP expression, in poorly differentiated HCC may relate to resistance to apoptosis.
authors.affiliation: Department of Pathology, Kurume University School of Medicine, Fukuoka 830-0011, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Sakemi
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Yano
authors.forename: Sachiko
authors.initials: S
authors.lastname: Ogasawara
authors.forename: Jun
authors.initials: J
authors.lastname: Akiba
authors.forename: Osamu
authors.initials: O
authors.lastname: Nakashima
authors.forename: Suguru
authors.initials: S
authors.lastname: Fukahori
authors.forename: Michio
authors.initials: M
authors.lastname: Sata
authors.forename: Masamichi
authors.initials: M
authors.lastname: Kojiro
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D022781:Hepatocytes / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007124:Immunoenzyme Techniques; D047908:Intracellular Signaling Peptides and Proteins; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism*; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism*; D016335:Zinc Fingers
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; D051636:X-Linked Inhibitor of Apoptosis Protein; C417551:XAF1 protein, human; C496866:XIAP protein, human