Mitoxantrone resistance in HL-60 leukemia cells: Reduced nuclear topoisomerase II catalytic activity and drug-induced DNA cleavage in association with reduced expression of the topoisomerase II. beta. isoform

Journal Article · Tue Oct 15 00:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00105a020· OSTI ID:5822728

Harker, W G; Slade, D L; Parr, R L ^[1]; Drake, F H ^[2]

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1. Univ. of Utah, Salt Lake City (United States)
2. SmithKline Beecham Pharmaceuticals, King of Prussia, PA (United States)

Mitoxantrone-resistant variants of the human HL-60 leukemia cell line are cross-resistant to several natural product and synthetic antineoplastic agents. The resistant cells (HL-60/MX2) retain sensitivity to the Vinca alkaloids vincristine and vinblastine, drugs that are typically associated with the classical multidrug resistance phenotype. Mitoxantrone accumulation and retention are equivalent in the sensitive and resistant cell types, suggesting that mitoxantrone resistance inn HL-60/MX2 cells might be associated with an alteration in the type II DNA topoisomerases. The authors discovered that topoisomerase II catalytic activity in 1.0 M NaCl nuclear extracts from the HL-60/MX2 variant was reduced 4- to 5-fold compared to that in the parental HL-60 cells. Studies were designed to minimize the proteolytic degradation of the topoisomerase II enzymes by extraction of whole cells with hot SDS. When nuclear extracts from the two cell types were normalized for equivalent catalytic activity, mitoxantrone inhibited the decatenation of kDNA by these extracts to an equal extent but levels of mitoxantrone-induced cleavage of {sup 32}P-labeled pBR322 DNA by nuclear extracts from HL-60/MX2 cells were 3- to 4-fold lower than in comparable HL-60 extracts. Resistance to the topoisomerase II inhibitor mitoxantrone in HL-60/MX2 is associated with reduced nuclear and whole cell topoisomerase II catalytic activity, immunologically undetectable levels of the 180-kDa topoisomerase II isozyme, and reduced mitoxantrone-induced cleavage of radiolabeled DNA by topoisomerase II in nuclear extracts from these cells.

• OSTI ID: 5822728
• Journal Information: Biochemistry; (United States), Vol. 30:41; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ALKALOIDS
BIOLOGICAL EFFECTS
ISOMERASES
ENZYME ACTIVITY
TUMOR CELLS
SENSITIVITY
ANTHRACENE
ENZYME INHIBITORS
LEUKEMIA
PHOSPHORUS 32
STRAND BREAKS
TRITIUM COMPOUNDS
ANIMAL CELLS
AROMATICS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CONDENSED AROMATICS
DAYS LIVING RADIOISOTOPES
DISEASES
ENZYMES
HYDROCARBONS
HYDROGEN COMPOUNDS
IMMUNE SYSTEM DISEASES
ISOTOPES
LIGHT NUCLEI
NEOPLASMS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOSPHORUS ISOTOPES
PROTEINS
RADIOISOTOPES
550200* - Biochemistry