title: Simvastatin and t-butylhydroquinone suppress KLF1 and BCL11A gene expression and additively increase fetal hemoglobin in primary human erythroid cells.
abstract: Although increased fetal hemoglobin (HbF) levels have proven benefit for people with β-hemoglobinopathies, all current HbF-inducing agents have limitations. We previously reported that drugs that activate the NRF2 antioxidant response signaling pathway increase HbF in primary human erythroid cells. In an attempt to increase HbF levels achieved with NRF2 activators, in the present study, we investigated potential complementary activity between these agents and HMG-CoA reductase inhibitors (statins) based on their ability to induce KLF2 protein levels. Experiments in K562 cells showed that simvastatin increased KLF2 mRNA and protein and KLF2 binding to HS2 of the β-globin locus control region and enhanced -globin mRNA production by the NRF2 activator Tert-butylhydroquinone (tBHQ). When tested in differentiating primary human erythroid cells, simvastatin induced HbF alone and additively with tBHQ, but it did not increase KLF2 mRNA or locus control region binding above levels seen with normal differentiation. Investigating alternative mechanisms of action, we found that both simvastatin and tBHQ suppress β-globin mRNA and KLF1 and BCL11A mRNA and protein, similar to what is seen in people with an HPFH phenotype because of KLF1 haploinsufficiency. These findings identify statins as a potential class of HbF-inducing agents and suggest a novel mechanism of action based on pharmacologic suppression of KLF1 and BCL11A gene expression.
  
  
  CONCLUSIONS
  Simvastatin and tBHQ suppress KLF1 and BCL11 gene expression and additively increase fetal hemoglobin in primary human erythroid cells. Because both drugs are FDA-approved, these findings could lead to clinical trials in the relatively near future.
authors.affiliation: Department of Medicine, Geisel School of Medicine, Dartmouth University, Hanover, NH, USA.
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Macari
authors.forename: Emily K
authors.initials: EK
authors.lastname: Schaeffer
authors.forename: Rachel J
authors.initials: RJ
authors.lastname: West
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Lowrey
mesh_terms: D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D041905:Erythroid Cells / Q000166:cytology / Q000378:metabolism*; D005260:Female; D005319:Fetal Hemoglobin / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000235:genetics; D056426:Genetic Loci / Q000502:physiology; D006801:Humans; D006873:Hydroquinones / Q000494:pharmacology*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D020014:K562 Cells; D051741:Kruppel-Like Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins; D019821:Simvastatin / Q000494:pharmacology*
chemical_list: C486563:BCL11A protein, human; D002352:Carrier Proteins; D006873:Hydroquinones; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D051741:Kruppel-Like Transcription Factors; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; C080774:erythroid Kruppel-like factor; D005319:Fetal Hemoglobin; D019821:Simvastatin; C018855:2-tert-butylhydroquinone