Benzodithiophenes potentiate differentiation of acute promyelocytic leukemia cells by lowering the threshold for ligand-mediated corepressor/coactivator exchange with retinoic acid receptor alpha and enhancing changes in all-trans-retinoic acid-regulated gene expression.
Differentiation induction is an effective therapy for acute promyelocytic leukemia (APL), which dramatically responds to all-trans-retinoic acid (ATRA). Recent studies have indicated that combinatorial use of retinoid and nonretinoid compounds, such as histone deacetylase inhibitors, arsenics, and PKA agonists, has higher therapeutic value in this disease and potentially in other malignancies. In a screen of 370 compounds, we identified benzodithiophene analogues as potent enhancers of ATRA-induced APL cell differentiation. These effects were not associated with changes in global histone acetylation and, for the most potent compounds, were exerted at very low nanomolar concentrations, and were paralleled by enhancement of some, but not all, ATRA-modulated gene expressions. Investigating the mechanism underlying the effects of these drugs on ATRA-induced APL cell differentiation, we have shown that benzodithiophenes enhance ATRA-mediated dissociation and association of corepressor N-CoR and coactivator p300 acetyltransferase, respectively, with retinoic acid receptor (RAR) alpha proteins. These data suggest that benzodithiophenes act at the level of receptor activation, possibly by affecting posttranslational modification of the receptor (and/or coregulators), thus leading to an enhancement in ATRA-mediated effects on gene expression and APL cell differentiation. Given the specificities of these low benzodithiophene concentrations for PML-RARalpha and RARalpha, these drugs may be useful for combinatorial differentiation therapy of APL and possibly other acute myelogenous leukemia subtypes in which the overall ATRA signaling is suppressed.
Xu
Ke
K
Section of Hemato-Oncology, Institute of Cancer Research, London, United Kingdom.
Guidez
Fabien
F
Glasow
Annegret
A
Chung
Danna
D
Petrie
Kevin
K
Stegmaier
Kimberly
K
Wang
Kan-Kan
KK
Zhang
Ji
J
Jing
Yongkui
Y
Zelent
Arthur
A
Waxman
Samuel
S
D002454:Cell Differentiation / Q000187:drug effects*; D004357:Drug Synergism; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects*; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D018168:Receptors, Retinoic Acid / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D000072482:Retinoic Acid Receptor alpha; D013876:Thiophenes / Q000494:pharmacology*; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology*; D020298:U937 Cells
C472166:LCOR protein, human; C000607071:RARA protein, human; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D000072482:Retinoic Acid Receptor alpha; D013876:Thiophenes; D014212:Tretinoin