title: Antitumor action of CDK inhibitor LS-007 as a single agent and in combination with ABT-199 against human acute leukemia cells.
abstract: OBJECTIVE
  LS-007 is a CDK inhibitor, which exhibits potent antitumor activity against chronic lymphocytic leukemia and ovarian cancer cells. In this study, we further evaluated the antitumor activity of LS-007 alone and in combination with a Bcl-2 inhibitor ABT-199 in acute leukemia (AL) cells.
  
  
  METHODS
  Cell viability was detected using resazurin assay, and cell apoptosis was examined using Annexin V/PI double staining and flow cytometry. The inhibition of LS-007 on kinases was evaluated with the mobility shift assay or ELISA. The expression of relevant signaling molecules was assessed using Western blotting and RT-PCR. Primary lymphocytes from patients with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) were separated using Ficoll-Paque PLUS.
  
  
  RESULTS
  LS-007 inhibited the proliferation of 6 AL cell lines with IC50values of 100-200 nmol/L, and decreased the survival of ALL and AML patient-derived lymphocytes with mean LD50value of 67 and 102 nmol/L, respectively. In kinase assays in vitro, LS-007 was more selective for the CDK family, inhibiting CDK2, CDK9, CDK1 and CDK4 at low nanomolar concentrations. In HL-60 and CCRF-CEM cells, LS-007 (0.1-0.4 μmol/L) dose-dependently induced cell apoptosis predominantly through CDK9 inhibition-related dephosphorylation at the ser2 residue of RNA pol II and the corresponding depletion of anti-apoptotic proteins, especially Mcl-1 and XIAP. LS-007 (0.2 and 0.4 μmol/L) also induced cell apoptosis in the patient-derived lymphocytes. In HL-60, CCRF-CEM and Molt-4 cells, combined application of LS-007 with ABT-199 (1 or 2 μmol/L) markedly increased cell apoptosis with a maximal decrease in the XIAP levels as compared with either drug used alone.
  
  
  CONCLUSIONS
  CDK inhibitor LS-007 potently inhibits the established human AL cell lines and primary AL blasts, and it also shows remarkable synergy with Bcl-2 inhibitor ABT-199.
authors: Division of Anti-tumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
authors: Shao
authors: S
authors: Xie
authors: Department of Hematology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai 200040, China.
authors: Hui
authors: H
authors: Jiang
authors: Department of Hematology and Oncology, Children's Hospital of Fudan University, Shanghai 201102, China.
authors: Xiao-Wen
authors: XW
authors: Zhai
authors: Division of Anti-tumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
authors: Fan
authors: F
authors: Wei
authors: School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5001, Australia.
authors: Shu-Dong
authors: SD
authors: Wang
authors: Division of Anti-tumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
authors: Jian
authors: J
authors: Ding
authors: Division of Anti-tumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
authors: Yi
authors: Y
authors: Chen
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D045744:Cell Line, Tumor / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002648:Child; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy*; D064549:Myeloid Cell Leukemia Sequence 1 Protein / Q000235:genetics / Q000378:metabolism; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy*; D011743:Pyrimidines / Q000494:pharmacology*; D013449:Sulfonamides / Q000494:pharmacology*; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000235:genetics / Q000378:metabolism; D000096926:Benzenesulfonamides
chemical_list: D000970:Antineoplastic Agents; D019086:Bridged Bicyclo Compounds, Heterocyclic; D018844:Cyclin-Dependent Kinases; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D011743:Pyrimidines; D013449:Sulfonamides; D051636:X-Linked Inhibitor of Apoptosis Protein; C000599930:3-(5-fluoro-4-(4-methyl-2-(methylamino)thiazol-5-yl)pyrimidin-2-ylamino)benzenesulfonamide; D000096926:Benzenesulfonamides; C579095:MCL1 protein, human; C496866:XIAP protein, human; C579720:venetoclax