Faculty Collaboration Database

Amplification and hyperexpression of the catalase gene in selenoperoxidase-deficient leukemia cells. Arch Biochem Biophys 1995 Feb 20;317(1):7-18

Date

02/20/1995

Pubmed ID

7872806

DOI

10.1006/abbi.1995.1129

Scopus ID

2-s2.0-0028967849 (requires institutional sign-in at Scopus site)   13 Citations

Abstract

Murine L1210 and human HL-60 leukemia cells grown for 5-7 days in medium containing 1% serum without selenium supplementation [Se(-) cells] were severely depressed in selenoperoxidase (SePX) activity relative to selenium-supplemented controls [Se(+) cells]. Catalase (CAT) activity in Se(-) cells was unaffected up to this point, but thereafter began to increase. Two manifestations of this increase have been differentiated for both cell lines: (a) short-term induction of CAT (up to approx. twofold) after 2-3 weeks, followed by (b) long-term selection for cells that irreversibly express much higher levels of CAT, e.g., > 100 times (L1210) and > 10 times (HL-60) the levels observed in Se(+) controls after approximately 20 weeks. Although superoxide dismutase, glutathione S-transferase, and glucose-6-P dehydrogenase activities were unchanged in Se(-) cells, GSH levels were elevated by 50-100%; like short-term CAT elevation, this could be reversed by supplying Se. Short-term Se(-) cells were more sensitive to H2O2-induced killing than Se(+) cells, evidently because SePX activity was important for peroxide detoxification. However, long-term Se(-) cells were markedly more resistant to H2O2 than Se(+) counterparts, consistent with the much higher levels of CAT in the former. Southern blot analysis revealed that the copy number of CAT DNA in a clone of long-term Se(-) L1210 cells was four- to fivefold greater than that in an Se(+) clone. Northern blot analysis of RNA from the same Se(-) clone showed a CAT mRNA level that was at least 40 times higher than that of the Se(+) control. Similar trends were observed for HL-60 cells. These results suggest that elevated CAT during long-term Se deprivation is a reflection of amplification and greater transcription of the CAT gene.

Author List

Lin F, Jackson VE, Girotti AW

Authors

Albert W. Girotti PhD Adjunct Professor in the Biochemistry department at Medical College of Wisconsin
Vaughn E. Jackson PhD Professor in the Biochemistry department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Catalase
DNA, Neoplasm
Gene Expression Regulation, Enzymologic
Gene Expression Regulation, Neoplastic
Humans
Hydrogen Peroxide
Leukemia
Mice
Peroxidases
Proteins
RNA, Messenger
Restriction Mapping
Selenium
Selenoproteins
Tumor Cells, Cultured