title: ON 01910.Na is selectively cytotoxic for chronic lymphocytic leukemia cells through a dual mechanism of action involving PI3K/AKT inhibition and induction of oxidative stress.
abstract: OBJECTIVE
  Chronic lymphocytic leukemia (CLL), a malignancy of mature B cells, is incurable with chemotherapy. Signals from the microenvironment support leukemic cell survival and proliferation and may confer chemotherapy resistance. ON 01910.Na (Rigosertib), a multikinase phosphoinositide 3-kinase (PI3K) inhibitor, is entering phase III trials for myelodysplastic syndrome. Our aim was to analyze the efficacy of ON 01910.Na against CLL cells in vitro and investigate the molecular effects of this drug on tumor biology.
  
  
  METHODS
  Cytotoxicity of ON 01910.Na against CLL cells from 34 patients was determined in vitro with flow cytometry of cells stained with Annexin V and CD19. Global gene expression profiling on Affymetrix microarrays, flow cytometry, Western blotting, and cocultures with stroma cells were used to delineate ON 01910.Na mechanism of action.
  
  
  RESULTS
  ON 01910.Na induced apoptosis in CLL B cells without significant toxicity against T cells or normal B cells. ON 01910.Na was equally active against leukemic cells associated with a more aggressive disease course [immunoglobulin heavy-chain variable region unmutated, adverse cytogenetics] than against cells without these features. Gene expression profiling revealed two main mechanisms of action: PI3K/AKT inhibition and induction of ROS that resulted in an oxidative stress response through activating protein 1 (AP-1), c-jun-NH(2)-terminal kinase, and ATF3 culminating in the upregulation of NOXA. ROS scavengers and shRNA mediated knockdown of ATF3- and NOXA-protected cells from drug-induced apoptosis. ON 01910.Na also abrogated the prosurvival effect of follicular dendritic cells on CLL cells and reduced SDF-1-induced migration of leukemic cells.
  
  
  CONCLUSIONS
  These data support the clinical development of ON 01910.Na in CLL.
authors.affiliation: Hematology Branch, NHLBI, NIH, Bld 10, CRC 3-5140, 10 Center Drive, 20892-1202 Bethesda, MD, USA.
authors.forename: Colby M
authors.initials: CM
authors.lastname: Chapman
authors.forename: Xiameng
authors.initials: X
authors.lastname: Sun
authors.forename: Mark
authors.initials: M
authors.lastname: Roschewski
authors.forename: Georg
authors.initials: G
authors.lastname: Aue
authors.forename: Mohamed
authors.initials: M
authors.lastname: Farooqui
authors.forename: Lawrence
authors.initials: L
authors.lastname: Stennett
authors.forename: Federica
authors.initials: F
authors.lastname: Gibellini
authors.forename: Diane
authors.initials: D
authors.lastname: Arthur
authors.forename: Patricia
authors.initials: P
authors.lastname: Pérez-Galán
authors.forename: Adrian
authors.initials: A
authors.lastname: Wiestner
mesh_terms: D051700:Activating Transcription Factor 3 / Q000235:genetics / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D045744:Cell Line, Tumor; D005260:Female; D020869:Gene Expression Profiling; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D057809:HEK293 Cells; D018922:HL-60 Cells; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress / Q000187:drug effects*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D013450:Sulfones / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: C490449:ATF3 protein, human; D051700:Activating Transcription Factor 3; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; C498702:PMAIP1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D013450:Sulfones; C507134:ON 01910; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D005998:Glycine