Zinc Depletion Modifies CD5 Expression by 70Z/3 Murine Pre-B Leukemia Cell Line

Abstract

CD5 expression on B cells is regulated by certain humoral factors. In a pre-B leukemia cell line 70Z/3, we found that interleukin 4 down-regulates it. Herein, we report that zinc influences spontaneous CD5 expression by this cell line as well as actions of these factors on CD5 expression considerably. In zinc-depleted culture media, spontaneous CD5 expression by 70Z/3 cells was enhanced. In contrast, the down-regulatory action of interleukin 4 was significantly reduced under culture conditions of zinc depletion. The supplementation of zinc to physiologic concentrations (1 to 2 microM) abolished such effects of zinc-depleted medium. The reduction of the suppressive action of interleukin 4 was observed at the level of gene expression. However, CD5 mRNA expression enhanced by lipopolysaccharide or NZB-SF was not further enhanced under conditions of zinc deficiency. These observations may suggest that CD5 expression by malignant or even normal B cells may be influenced by cellular/serum zinc levels.

Zinc is required for the expression of ornithine decarboxylase in a difluoromethylornithine-resistant cell line

“…In fact, treatment of the cells with the chelator DTPA inhibited ODC induction, although not completely, and the inhibition was reversed by Zn2+, whereas other bivalent-metal ions were scarcely effective. Restricted Zn2+ availability has been reported to inhibit or, more rarely, to enhance, the expression of particular proteins in various cell types [5][6][7][8]. In particular, DTPA was found to prevent myoblast differentiation along with the increase in creatine kinase activity and mRNA, determined in isolated myoblasts after a few days of treatment, and these effects were prevented by Zn2+ addition [15].…”

“…The control of these genes by Zn2+ may be mediated by 'Zn finger' transcription factors and by 'metal regulatory elements'. Actually, the expression of specific proteins appears to be altered in Zn2+-deficient cells generally, but not always in a negative fashion [5][6][7][8].…”