DIFFERENTIAL-EFFECTS OF TUMOR PROMOTERS AND CYTOKINES ON PROTOONCOGENE EXPRESSION IN A HEMATOPOIETIC CYTOKINE-DEPENDENT CELL-LINE
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- Published online on: March 1, 1994 https://doi.org/10.3892/or.1.2.285
- Pages: 285-300
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Abstract
In order to investigate the mechanisms by which cytokines and tumor promoters stimulate cell growth, the expression of genes implicated in the regulation of cellular proliferation were examined in an interleukin-3 (IL-3) dependent hematopoietic cell line. Upon stimulation of factor-deprived cells with IL-3, mRNA transcripts encoding the immediate-early genes: c-myc, jun-B, krox-20, beta-actin, and the cytokine genes: IL-4 and IL-6 were detected within 1 h. In contrast mRNA transcripts encoding the delayed-early genes: ornithine decarboxylase, p53, the IL-2 receptor-alpha, IL-4 receptor, and the T cell receptor c-gamma chains were observed at highest levels later. The tumor promoter, phorbol 12-myristate 13-acetate also stimulated the expression of many immediate-early genes, however, c-myc and the delayed-early genes were only detected when IL-3 was present. We conclude that cytokines and tumor promoters have distinct effects on proto-oncogene expression in hematopoietic cells which may affect the ability of these agents to promote cellular growth versus differentiation.