title: The proteasome controls the expression of a proliferation-associated nuclear antigen Ki-67.
abstract: The proteasome is a protease complex responsible for rapid, selective, and irreversible removal of regulatory proteins, as well as many other cellular proteins. In this study, we have demonstrated that a proliferation-associated nuclear protein Ki-67 depended on the proteasome for its rapid degradation. A proteasome-specific inhibitor lactacystin augmented Ki-67 protein levels in pancreatic cancer BxPC-3 cells while repressed the level of steady-state Ki-67 mRNA. Inhibition of the proteasome also led to accumulation of two CDK inhibitors p27(kip1) and p21(cip1) in the BxPC-3 cells. Failed reduction of Ki-67 protein and enhanced levels of the two CDK inhibitors are likely contributing factors for the suppressed BxPC-3 proliferation after proteasome inhibition.
authors.affiliation: Department of Surgery, Second Affiliated Hospital of Zhejiang Medical College, Zhejiang University, Hangzhou, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Wu
authors.forename: H
authors.initials: H
authors.lastname: Luo
authors.forename: N
authors.initials: N
authors.lastname: Kanaan
authors.forename: J
authors.initials: J
authors.lastname: Wu
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000187:drug effects; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D016213:Cyclins / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D012333:RNA, Messenger / Q000187:drug effects; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
chemical_list: C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D019394:Ki-67 Antigen; D008869:Microtubule-Associated Proteins; D009097:Multienzyme Complexes; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins; C067713:lactacystin; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D000111:Acetylcysteine