title: Regulation of the nuclear proteasome activity in myelomonocytic human leukemia cells after adriamycin treatment.
abstract: Treatment of different human leukemia cell variants with the anthracycline adriamycin was associated with a rapid activation of the proteasome. Thus, proliferating U937, TUR, and retrodifferentiated U937 cells exhibited a 4.3-fold, 5.8-fold, and 4.3-fold proteasome activation within 15 minutes after adriamycin treatment, respectively. In contrast, little if any proteasome activation was detectable in a growth-arrested differentiated U937 population following adriamycin treatment. Further analysis of this mechanism revealed a significant reduction of adriamycin-induced proteasome activity after inhibition of poly(ADP-ribose) polymerase (PARP) by 3-aminobenzamide (3-ABA) in the proliferating leukemic cell types. These findings suggested that PARP is involved in the regulation of drug-induced proteasome activation. Indeed, anti-PARP immunoprecipitation experiments of adriamycin-treated cells revealed increasing levels of coprecipitated, enzymatically active proteasome particularly in the proliferating cell variants in contrast to the differentiated U937 cells, with a maximum after 15 minutes, and sensitivity to PARP inhibition by 3-ABA. The specific role of the PARP was investigated in U937 and TUR cell clones stably transfected with a constitutively active antisense PARP (asPARP) vector. Thus, asPARP-TUR cells developed a 25-fold increased sensitivity to adriamycin treatment. Furthermore, we investigated leukemic blasts isolated from acute myelogenous leukemia patients and obtained a similarly enhanced proteasome activity after adriamycin treatment, which was dependent on the PARP and thus could be coprecipitated with anti-PARP antibodies. Transient transfection of leukemic blasts with the asPARP vector significantly reduced the adriamycin-induced proteasome activation. These data suggest that the PARP-associated nuclear proteasome activation represents a potential target within chemotherapeutic defense mechanisms developed by leukemia cells.
authors: Department of Cell and Neurobiology, Institute of Anatomy, and Department of Hematology and Oncology, University Hospital Charité, Humboldt University, Berlin, Germany.
authors: O
authors: O
authors: Ciftci
authors: O
authors: O
authors: Ullrich
authors: C A
authors: CA
authors: Schmidt
authors: A
authors: A
authors: Diestel
authors: R
authors: R
authors: Hass
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004317:Doxorubicin / Q000494:pharmacology* / Q000627:therapeutic use; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D015479:Leukemia, Myelomonocytic, Acute / Q000188:drug therapy* / Q000201:enzymology*; D009097:Multienzyme Complexes / Q000378:metabolism*; D016376:Oligonucleotides, Antisense; D046988:Proteasome Endopeptidase Complex; D014162:Transfection; D020298:U937 Cells
chemical_list: D000970:Antineoplastic Agents; D009097:Multienzyme Complexes; D016376:Oligonucleotides, Antisense; D004317:Doxorubicin; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex