title: [Drug resistance of acute promyelocytic leukemia (APL) to all-trans retinoic acid (ATRA) and its reversion].
abstract: OBJECTIVE
  To study the mechanism of drug resistance of APL to ATRA and the methods of reversion.
  
  
  METHODS
  ATRA-resistant HL60 cell line and bone marrow (BM) leukemia cells from recurrent APL patients who did not respond to ATRA treatment were used in this study. Multiple drug resistance gene (mdr1) expression was determined by RT-PCR and flow cytometry. Cell proliferation and differentiation were assessed by MTT uptake and NBT reduction respectively.
  
  
  RESULTS
  The response of ATRA-resistant HL60 and APL cells from recurrent patients to the differentiation inducing activity of ATRA was significantly reduced, and ATRA had little effect on cell proliferation. Expression of mdr-1 was nagative in ATRA-resistant HL60 cells. It was negative in resistant APL cells even after ATRA treatment. Arsenic trioxide and homoharringtonine (HHT) could inhibit proliferation of HL60 and ATRA-resistant HL60 cells, indicating no cross-resistance with ATRA. Interferon alpha (IFN-alpha) and PGE1 could significantly inhibit proliferation of ATRA-resistant HL60 cells and restore cell differentiation induced by ATRA.
  
  
  CONCLUSIONS
  Drug resistance of APL to ATRA is not related to mdr-1. It can be reversed by IFN-alpha. There is no cross-resistance between HHT or arsenic trioxide and ATRA.
authors.affiliation: Department of Hematology and Oncology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan 250062, China.
authors.forename: G
authors.initials: G
authors.lastname: Jiang
authors.forename: T
authors.initials: T
authors.lastname: Tang
authors.forename: K
authors.initials: K
authors.lastname: Bi
mesh_terms: D000527:Alprostadil / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D004347:Drug Interactions; D004351:Drug Resistance / Q000502:physiology; D018922:HL-60 Cells; D006248:Harringtonines / Q000494:pharmacology; D000077863:Homoharringtonine; D006801:Humans; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000494:pharmacology; D015473:Leukemia, Promyelocytic, Acute; D010087:Oxides / Q000494:pharmacology; D011994:Recombinant Proteins; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D000972:Antineoplastic Agents, Phytogenic; D001152:Arsenicals; D006248:Harringtonines; D000077190:Interferon alpha-2; D016898:Interferon-alpha; D010087:Oxides; D011994:Recombinant Proteins; D014212:Tretinoin; D000077863:Homoharringtonine; D000527:Alprostadil; D000077237:Arsenic Trioxide