Resistance to hydrogen peroxide associated with altered catalase mRNA stability in MCF7 breast cancer cells.
We have established a variant of the human breast cancer cell line MCF7, designated MCF7/H2O2, which is 5-fold resistant to H2O2 by clonogenic assay. The specific activity of the H2O2 disposal enzyme catalase was elevated 3-fold in MCF7/H2O2; activities of other antioxidant enzymes, including glutathione peroxidase and superoxide dismutase, were not increased. The steady-state level of catalase mRNA was only slightly elevated (approx. 1.6-fold) in MCF7/H2O2 cells; however, degradation of catalase mRNA was markedly retarded in MCF-7/H2O2 compared to MCF-7 (82% of catalase mRNA remained 24 h after inhibition of RNA synthesis by actinomycin D in MCF-7/H2O2 vs. 32% in MCF7). The degradation rates of superoxide dismutase mRNA and 28 S ribosomal RNA were not reduced in MCF-7/H2O2; however, the rate of degradation of another mRNA species, beta-actin, was also significantly decreased. These data suggest that resistance to H2O2 in MCF7/H2O2 cells is mediated by elevated catalase activity which can be explained by stabilization of certain mRNA species, including catalase mRNA.
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- Tumor Cells, Cultured
- Superoxide Dismutase
- RNA, Messenger
- Hydrogen Peroxide
- Humans
- Half-Life
- Glutathione Peroxidase
- Drug Resistance
- Dactinomycin
- Catalase
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Tumor Cells, Cultured
- Superoxide Dismutase
- RNA, Messenger
- Hydrogen Peroxide
- Humans
- Half-Life
- Glutathione Peroxidase
- Drug Resistance
- Dactinomycin
- Catalase