Efficacy of gemtuzumab ozogamicin on ATRA- and arsenic-resistant acute promyelocytic leukemia (APL) cells

Leukemia. 2005 Aug;19(8):1306-11. doi: 10.1038/sj.leu.2403807.


Acute promyelocytic leukemia (APL) cells express a considerable level of CD33, which is a target of gemtuzumab ozogamicin (GO), and a significantly lower level of P-glycoprotein (P-gp). In this study, we examined whether GO was effective on all-trans retinoic acid (ATRA)- or arsenic trioxide (ATO)-resistant APL cells. Cells used were an APL cell line in which P-gp was undetectable (NB4), ATRA-resistant NB4 (NB4/RA), NB4 and NB4/RA that had been transfected with MDR-1 cDNA (NB4/MDR and NB4/RA/MDR, respectively), ATO-resistant NB4 (NB4/As) and blast cells from eight patients with clinically ATRA-resistant APL including two patients with ATRA- and ATO-resistant APL. The efficacy of GO was analyzed by (3)H-thymidine incorporation, the dye exclusion test and cell cycle distribution. GO suppressed the growth of NB4, NB4/RA and NB4/As cells in a dose-dependent manner. GO increased the percentage of hypodiploid cells significantly in NB4, NB4/RA and NB4/As cells, and by a limited degree in NB4/MDR and NB4/RA/MDR cells. Similar results were obtained using blast cells from the patients with APL. GO is effective against ATRA- or ATO-resistant APL cells that do not express P-gp, and the mechanism of resistance to GO is not related to the mechanism of resistance to ATRA or ATO in APL cells. Leukemia (2005) 19, 1306-1311. doi:10.1038/sj.leu.2403807; published online 26 May 2005.

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / analysis
  • Aminoglycosides / pharmacology*
  • Antibodies, Monoclonal / pharmacology*
  • Antibodies, Monoclonal, Humanized
  • Arsenic Trioxide
  • Arsenicals / pharmacology
  • Cell Cycle
  • Cell Proliferation / drug effects
  • Drug Resistance, Neoplasm*
  • Gemtuzumab
  • Humans
  • Leukemia, Promyelocytic, Acute / drug therapy
  • Leukemia, Promyelocytic, Acute / pathology*
  • Oxides / pharmacology
  • Treatment Outcome
  • Tretinoin / pharmacology
  • Tumor Cells, Cultured


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Aminoglycosides
  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Arsenicals
  • Oxides
  • Tretinoin
  • Gemtuzumab
  • Arsenic Trioxide