title: Synergistic Effect and Molecular Mechanism of Homoharringtonine and Bortezomib on SKM-1 Cell Apoptosis.
abstract: BACKGROUND
  Myelodysplastic syndromes (MDS) are clonal marrow stem-cell disorders with a high risk of progression to acute myeloid leukemia (AML). Treatment options are limited and targeted therapies are not available for MDS. In the present study, we investigated the cytotoxicity and the molecular mechanism of Homoharringtonine (HHT) and Bortezomib towards high-risk MDS cell line SKM-1 in vitro and the role of miR-3151 was first evaluated in SKM-1 cells.
  
  
  METHODS
  SKM-1 cells were treated with different concentrations of HHT or Bortezomib, and cell viability was analyzed with CCK-8 assay. The influence on cell proliferation, cell cycle distribution and the percentage of apoptosis cells were analyzed by flow cytometry. Calcusyn software was used to calculate combination index (CI) values. Western blot was used to analysis phosphorylation of Akt and nuclear NF-κB protein expression in SKM-1 cells. Mature miR-3151 level and p53 protein level were detected after HHT or Bortezomib treatment. The cell proliferation and p53 protein level were reassessed in SKM-1 cells infected with lentivirus to overexpress miR-3151.
  
  
  RESULTS
  Simultaneous exposure to HHT and Bortezomib (10.4:1) resulted in a significant reduction of cell proliferation in SKM-1 cells (P < 0.05). Cell cycle arrest at G0/G1 and G2/M phase was observed (P < 0.05). HHT and Bortezomib synergistically induced cell apoptosis by regulating members of caspase 9, caspase 3 and Bcl-2 family (P < 0.01). The mechanisms of the synergy involved Akt and NF-κB signaling pathway inhibition, downregulation of mature miR-3151 and increment of downstream p53 protein level. Overexpression of miR-3151 promoted cell proliferation and inhibited p53 protein expression in SKM-1 (P < 0.01).
  
  
  CONCLUSIONS
  HHT and Bortezomib synergistically inhibit SKM-1 cell proliferation and induce apoptosis in vitro. Inhibition of Akt and NF-κB pathway signaling contribute to molecular mechanism of HHT and Bortezomib. miR-3151 abundance is implicated in SKM-1 cell viability, cell proliferation and p53 protein expression.
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Bobin
authors.initials: B
authors.lastname: Chen
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Wu
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhuang
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhu
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Ni
authors.initials: N
authors.lastname: Fan
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Wenjiao
authors.initials: W
authors.lastname: Qing
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Xu
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D000069286:Bortezomib / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival; D005434:Flow Cytometry; D006248:Harringtonines / Q000494:pharmacology*; D000077863:Homoharringtonine; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D012984:Software
chemical_list: D006248:Harringtonines; D016328:NF-kappa B; D000069286:Bortezomib; D000077863:Homoharringtonine