title: Efficacy of gemtuzumab ozogamicin on ATRA- and arsenic-resistant acute promyelocytic leukemia (APL) cells.
abstract: 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.
authors.affiliation: Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan. akihirot@hama-med.ac.jp
authors.forename: A
authors.initials: A
authors.lastname: Takeshita
authors.forename: K
authors.initials: K
authors.lastname: Shinjo
authors.forename: K
authors.initials: K
authors.lastname: Naito
authors.forename: H
authors.initials: H
authors.lastname: Matsui
authors.forename: N
authors.initials: N
authors.lastname: Sahara
authors.forename: K
authors.initials: K
authors.lastname: Shigeno
authors.forename: T
authors.initials: T
authors.lastname: Horii
authors.forename: N
authors.initials: N
authors.lastname: Shirai
authors.forename: M
authors.initials: M
authors.lastname: Maekawa
authors.forename: K
authors.initials: K
authors.lastname: Ohnishi
authors.forename: T
authors.initials: T
authors.lastname: Naoe
authors.forename: R
authors.initials: R
authors.lastname: Ohno
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis; D000617:Aminoglycosides / Q000494:pharmacology*; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology; D002453:Cell Cycle; D049109:Cell Proliferation / Q000187:drug effects; D019008:Drug Resistance, Neoplasm; D000079982:Gemtuzumab; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000188:drug therapy / Q000473:pathology*; D010087:Oxides / Q000494:pharmacology; D016896:Treatment Outcome; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000617:Aminoglycosides; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D001152:Arsenicals; D010087:Oxides; D014212:Tretinoin; D000079982:Gemtuzumab; D000077237:Arsenic Trioxide