Aurora-A overexpression in mouse liver causes p53-dependent premitotic arrest during liver regeneration.
Aurora-A, a serine-threonine kinase, is frequently overexpressed in human cancers, including hepatocellular carcinoma. To study the phenotypic effects of Aurora-A overexpression on liver regeneration and tumorigenesis, we generated transgenic mice overexpressing human Aurora-A in the liver. The overexpression of Aurora-A after hepatectomy caused an earlier entry into S phase, a sustaining of DNA synthesis, and premitotic arrest in the regenerating liver. These regenerating transgenic livers show a relative increase in binuclear hepatocytes compared with regenerating wild-type livers; in addition, multipolar segregation and trinucleation could be observed only in the transgenic hepatocytes after hepatectomy. These results together suggest that defects accumulated after first round of the hepatocyte cell cycle and that there was a failure to some degree of cytokinesis. Interestingly, the p53-dependent checkpoint was activated by these abnormalities, indicating that p53 plays a crucial role during liver regeneration. Indeed, the premitotic arrest and abnormal cell death, mainly necrosis, caused by Aurora-A overexpression were genetically rescued by p53 knockout. However, trinucleation of hepatocytes remained in the regenerating livers of the transgenic mice with a p53 knockout background, indicating that the abnormal mitotic segregation and cytokinesis failure were p53 independent. Moreover, overexpression of Aurora-A in transgenic liver led to a low incidence (3.8%) of hepatic tumor formation after a long latency period. This transgenic mouse model provides a useful system that allows the study of the physiologic effects of Aurora-A on liver regeneration and the genetic pathways of Aurora-A-mediated tumorigenesis in liver.
Li
Chao-Chin
CC
Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, 155 Li-Nong Street, Section 2, Peitou, Taipei 112, Taiwan.
Chu
Hui-Yi
HY
Yang
Chu-Wen
CW
Chou
Chen-Kung
CK
Tsai
Ting-Fen
TF
D000818:Animals; D064096:Aurora Kinase A; D064127:Aurora Kinases; D015152:Blotting, Northern; D015153:Blotting, Western; D005260:Female; D016195:G2 Phase; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D006498:Hepatectomy; D006801:Humans; D007150:Immunohistochemistry; D008099:Liver / Q000196:embryology / Q000378:metabolism* / Q000503:physiopathology; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008115:Liver Regeneration; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008938:Mitosis; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016196:S Phase; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; C576918:Aurka protein, mouse; D064096:Aurora Kinase A; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases