Effects of wild-type p53 expression on the quantity and activity of topoisomerase IIα and β in various human cancer cell lines Journal Article

  


Authors: Hochhauser, D.; Valkov, N. I.; Gump, J. L.; Wei, I.; O'Hare, C.; Hartley, J.; Fan, J.; Bertino, J. R.; Banerjee, D.; Sullivan, D. M.
Article Title: Effects of wild-type p53 expression on the quantity and activity of topoisomerase IIα and β in various human cancer cell lines
Abstract: The p53 null HL-60 cell line was transfected with plasmids coding for either the wild-type p53 or mutant p53 gene. The stable expression of wild- type p53 resulted in a significant increase in sensitivity to the topoisomerase II poisons etoposide and doxorubicin, but not to the topoisomerase II inhibitors razoxane and ADR-529. HL-60 cells expressing wild-type p53 demonstrated 8- to 10-fold more VP-16 induced DNA breaks by the alkaline elution assay. The effect of inducible expression of wild-type p53 was also studied in the p53 null erythroblastoid cell line K562 and in the human squamous carcinoma cell line SqCC. The inducible expression of wild- type p53 in the K562 cell line resulted in a 3-fold increase in sensitivity to VP-16. The quantity of topoisomerase IIα was not altered by the transfection as determined by immunoblotting, while the amount of the β isoform was increased 2.5-fold in HL-60 cells. The topo II catalytic activity present in nuclear extracts was measured as the decatenation of kinetoplast DNA, and found to be unaltered by p53 expression. Immunostaining for topoisomerase IIα was substantially diminished in both stable and inducible wild-type p53 expressing cells when three different antibodies were used (two polyclonal and one monoclonal). However, the addition of VP-16 resulted in a rapid appearance of nuclear fluorescence for topoisomerase Ilα. No changes in topoisomerase Ilβ immunostaining were observed. These results suggest that an epitope for topoisomerase Ilα is concealed in cells expressing wild- type p53 and that a complex between topoisomerase Ilα and p53 may be disrupted by the addition of antitumor drugs.
Keywords: immunohistochemistry; controlled study; protein expression; human cell; dna-binding proteins; carcinoma, squamous cell; doxorubicin; gene expression; etoposide; cancer cell culture; immunofluorescence; tumor cells, cultured; enzyme activity; transfection; protein p53; time factors; blotting, western; antigens, neoplasm; immunoblotting; tumor suppressor protein p53; microscopy, fluorescence; catalysis; dna topoisomerase inhibitor; dna topoisomerase (atp hydrolysing); drug sensitivity; hemoglobins; isoenzymes; p53; dna topoisomerases, type ii; dna topoisomerases, type ii, eukaryotic; k562 cells; razoxane; hl-60 cells; cell strain hl 60; precipitin tests; humans; human; priority journal; article; topoisomerase ii; vp-16
Journal Title: Journal of Cellular Biochemistry
Volume: 75
Issue: 2
ISSN: 0730-2312
Publisher: John Wiley & Sons  
Date Published: 1999-11-01
Start Page: 245
End Page: 257
Language: English
DOI: 10.1002/(sici)1097-4644(19991101)75:2<245::aid-jcb7>3.0.co;2-g
PUBMED: 10502297
PROVIDER: scopus
DOI/URL:

https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033232044&partnerID=40&md5=2492f20a5d3780673840550a4717ec1e
Notes: Article -- Export Date: 16 August 2016 -- Source: Scopus
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MSK Authors
  1. Jianguo Fan
    30 Fan
  2. Joseph Bertino
    363 Bertino
  3. Daniel Hochhauser
    15 Hochhauser
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