The pathway of leukemic cell death caused by glucocorticoid receptor fragment 465

Mohamed El-Naghy, Betty H. Johnson, Hong Chen, Naseem Ansari, Weiping Zhang, Peter Moller, Yan shan Ji, E. Brad Thompson

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

The truncated glucocorticoid receptor mutant gene 465* codes for a protein that is interrupted by a frameshift mutation in the second zinc finger of the natural DNA binding domain. Thus, 465* represents the natural amino acid sequence 1-465 followed by 21 novel amino acids starting at position 466. The entire ligand binding domain is missing. Prior studies have shown that transient transfection of the glucocorticoid-resistant leukemic T-cell clone ICR-27 with a plasmid expressing 465* rapidly reduces the number of viable cells. This response does not require activation by a steroid, and a hybrid protein consisting of green fluorescent protein fused to 465* is found primarily in the cytoplasm. In the present study, we present evidence that the decrease in cell number is due to a form of cell death that bears many of the classic characteristics of apoptosis. Expression of the 465* protein can be detected a few hours after electroporation and is followed by activation of caspase-3 as well as reduction of the mitochondrial inner transmembrane potential. The caspase-3 inhibitor ZVAD.fmk blocks 465*-dependent cell death when added acutely after electroporation, but fails to do so later. We conclude that the novel 465* gene causes cell death by apoptosis.

Original languageEnglish (US)
Pages (from-to)166-175
Number of pages10
JournalExperimental Cell Research
Volume270
Issue number2
DOIs
StatePublished - Nov 1 2001

    Fingerprint

Keywords

  • Apoptosis
  • Caspase-3
  • Glucocorticoid receptor fragment
  • Mitochondria
  • T-cell leukemia

ASJC Scopus subject areas

  • Cell Biology

Cite this

El-Naghy, M., Johnson, B. H., Chen, H., Ansari, N., Zhang, W., Moller, P., Ji, Y. S., & Thompson, E. B. (2001). The pathway of leukemic cell death caused by glucocorticoid receptor fragment 465. Experimental Cell Research, 270(2), 166-175. https://doi.org/10.1006/excr.2001.5350