title: Nutlin-1 strengthened anti-proliferation and differentiation-inducing activity of ATRA in ATRA-treated p-glycoprotein deregulated human myelocytic leukemia cells.
abstract: Unlike its cytotoxicity in p53-functional cell lines, Nutlin-1, the small-molecule inhibitor of murine double minute (MDM2), significantly enhanced the differentiation-inducing activity of all-trans retinoic acid (ATRA) in HL60 and NB4 cells (p53-nonfunctional) but not in U937 cells (p53 wild-type). Moreover, we demonstrated that the synergistic differentiation-inducing activity of Nutlin-1 combined with ATRA appeared in a p53-independent manner. In the present study, we found that ATRA could selectively induce expression of p-glycoprotein (p-gp) in HL60 and NB4 cells but not in U937 cells. Investigation of p-gp-ATPase activity showed that Nutlin-1 and ATRA were likely to act as p-gp transport substrates. Furthermore, Nutlin-1 enhanced the ability of ATRA to induce expression of the myeloid differentiation-related transcription factor C/EBPβ and to reduce expression of c-myc. Additionally, the expression of retinoic acid receptor α (RARα) was further reduced in cells treated with ATRA in combination with Nutlin-1. Taken together, the mechanisms of synergistic differentiation-inducing activity of Nutlin-1 combined with ATRA could be attributed to Nutlin-1 competitive binding to p-gp, leading to ATRA efflux inhibition, and then the differentiation pathways involved were therefore further activated. Nutlin-1 might be a useful adjuvant with ATRA for patients with retinoid-resistant leukemia induced by overexpression of p-gp.
authors.affiliation: Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, Zhejiang University, 388# Yuhangtang Rd., Hangzhou 310058, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Yan
authors.forename: Difeng
authors.initials: D
authors.lastname: Zhu
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Weisi
authors.initials: W
authors.lastname: Wang
authors.forename: Yongzhou
authors.initials: Y
authors.lastname: Hu
authors.forename: Bo
authors.initials: B
authors.lastname: Yang
authors.forename: Qiaojun
authors.initials: Q
authors.lastname: He
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D001667:Binding, Competitive; D001692:Biological Transport; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D018922:HL-60 Cells; D006801:Humans; D007093:Imidazoles / Q000378:metabolism / Q000494:pharmacology; D007951:Leukemia, Myeloid / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D010879:Piperazines / Q000378:metabolism / Q000494:pharmacology; D051736:Proto-Oncogene Proteins c-mdm2 / Q000037:antagonists & inhibitors / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D034622:RNA Interference; D018168:Receptors, Retinoic Acid / Q000378:metabolism; D000072482:Retinoic Acid Receptor alpha; D013997:Time Factors; D014162:Transfection; D014212:Tretinoin / Q000378:metabolism / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D020298:U937 Cells; D014700:Verapamil / Q000494:pharmacology
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D022782:CCAAT-Enhancer-Binding Protein-beta; C545012:CEBPB protein, human; D007093:Imidazoles; C489427:MYC protein, human; D010879:Piperazines; D016271:Proto-Oncogene Proteins c-myc; C000607071:RARA protein, human; D018168:Receptors, Retinoic Acid; D000072482:Retinoic Acid Receptor alpha; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C482203:nutlin 1; D014212:Tretinoin; D014700:Verapamil; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2