This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Harmon, J. M. Articles by Baione, K. A. Search for Related Content PubMed PubMed Citation Articles by Harmon, J. M. Articles by Baione, K. A.

Analysis of Glucocorticoid-resistant Human Leukemic Cells by Somatic Cell Hybridization¹

Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814 [J. M. H., K. A. B.] and Laboratory of Biochemistry, Division of Cancer Biology and Diagnosis, National Cancer Institute, Bethesda, Maryland 20205 [E. B. T.]

Glucocorticoid-resistant mutants isolated from the glucocorticoid-sensitive human leukemic cell line CEM-C7 can be divided into three phenotypes: (a) those with almost no glucocorticoid-binding activity (r^-); (b) those whose steroid-receptor complexes are unstable during attempted activation but are stabilized by the presence of sodium molybdate (act¹:molybdate-sensitive); and (c) those whose steroid-receptor complexes are unstable during attempted activation but are insensitive to the presence of molybdate (act¹:molybdate-resistant). To determine if these phenotypes represent different mutations within the glucocorticoid receptor locus itself or reflect alterations in other components modifying receptor function, somatic hybrids were constructed between wild-type cells and all three classes of resistant mutants, as well as between various classes of resistant mutants. Hybrids were analyzed for chromosome content, steroid-induced growth inhibition, induction of the enzyme glutamine synthetase, and glucocorticoid receptor content. Hybrids constructed between wild-type cells and any of the three classes of resistant cells were growth-inhibited in the presence of dexamethasone, displayed normal levels of glutamine synthetase induction, and contained a quantity of glucocorticoid receptor approximately equal to the sum of the glucocorticoid receptor concentrations of the parental cell lines. Hybrids constructed between various classes of resistant cells were not growth-inhibited by dexamethasone, displayed no glutamine synthetase induction, and also contained the sum of the glucocorticoid receptor concentration of the individual parents. Thus, each phenotype is recessive, and there is no complementation between phenotypes. We conclude that the three phenotypes are the results of different mutations within the glucocorticoid receptor locus itself and do not represent the presence of dominant receptor-inactivating factors or the absence of positive regulatory components.

¹ Supported by Grant CA 32226 from the National Cancer Institute to J. M. H.

² To whom requests for reprints should be addressed.

³ Present address: Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston, TX 77550.

Received 9/17/84. Revised 12/26/84. Accepted 12/31/84.

This article has been cited by other articles:

				A. G. Hillmann, J. Ramdas, K. Multanen, M. R. Norman, and J. M. Harmon Glucocorticoid Receptor Gene Mutations in Leukemic Cells Acquired in Vitro and in Vivo Cancer Res., April 1, 2000; 60(7): 2056 - 2062. [Abstract] [Full Text]