title: Therapeutic targeting of nuclear receptor corepressor misfolding in acute promyelocytic leukemia cells with genistein.
abstract: We have recently reported that PML-RAR-induced misfolding of the N-CoR protein could be reversed by retinoic acid (RA), a therapeutic agent that promotes differentiation of acute promyelocytic leukemia (APL) cells. This finding suggests a role of misfolded N-CoR in the differentiation arrest of APL cells and highlights its significance as a potential molecular target in protein conformation-based therapy for APL. Based on this hypothesis, we investigated the therapeutic potential of several protein conformation modifiers on APL-derived cell lines NB4 and NB4-R1. Through a small-scale screening of these selected compounds, we identified genistein as a potent inhibitor of growth of both RA-sensitive and RA-resistant APL cells. Genistein inhibited the growth of NB4 cells through its collective regulatory effects on cell cycle progression, differentiation, and apoptosis. Genistein-induced apoptosis of NB4 cells was mediated by activation of caspase-9 and caspase-3 and was associated with a decrease in mitochondrial transmembrane potential and cytosolic release of cytochrome c. Genistein promoted differentiation of both RA-sensitive and RA-resistant NB4 cells and induced cell cycle arrest by blocking the G(2)-M transition. Genistein up-regulated the expression of PML and N-CoR proteins, promoted degradation of PML-RAR, and reorganized the microspeckled distribution of PML oncogenic domains to a normal dot-like pattern in NB4 cells. Moreover, genistein significantly reversed the PML-RAR-induced misfolding of N-CoR protein by possibly inhibiting the selective phosphorylation-dependent binding of N-CoR to PML-RAR. These findings identify genistein as a potent modifier of N-CoR protein conformation and highlights its therapeutic potential in both RA-sensitive and RA-resistant APL cells.
authors: Oncology Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, 02-07, Center for Life Sciences, 28 Medical Drive, Singapore 117456.
authors: Angela Ping Ping
authors: AP
authors: Ng
authors: Dawn Sijin
authors: DS
authors: Nin
authors: Jek Howe
authors: JH
authors: Fong
authors: Divya
authors: D
authors: Venkataraman
authors: Chien-Shing
authors: CS
authors: Chen
authors: Matiullah
authors: M
authors: Khan
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D015536:Down-Regulation / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D019833:Genistein / Q000494:pharmacology*; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000201:enzymology / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D009363:Neoplasm Proteins / Q000737:chemistry; D009687:Nuclear Proteins / Q000737:chemistry* / Q000378:metabolism*; D056971:Nuclear Receptor Co-Repressor 1; D010447:Peptide Hydrolases / Q000235:genetics; D010768:Phosphoserine / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D000071156:Promyelocytic Leukemia Protein; D011485:Protein Binding / Q000187:drug effects; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D018168:Receptors, Retinoic Acid / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry; D014212:Tretinoin / Q000494:pharmacology; D025521:Tumor Suppressor Proteins / Q000737:chemistry
chemical_list: D000970:Antineoplastic Agents; C539127:NCOR1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D056971:Nuclear Receptor Co-Repressor 1; D000071156:Promyelocytic Leukemia Protein; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C070576:PML protein, human; D010768:Phosphoserine; D019000:Phosphotyrosine; D014212:Tretinoin; D019833:Genistein; D010447:Peptide Hydrolases; D053148:Caspase 3; D053453:Caspase 9