Insulin-like growth factor binding protein-5 gene expression is differentially regulated at a post-transcriptional level in retinoic acid-sensitive and resistant mcf-7 human breast carcinoma cells

M. Saeed Sheikh, Zhi Ming Shao, Jian Chyi Chen, David R. Clemmons, Charles T. Roberts, Derek LeRoith, Joseph A. Fontana

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    11 Scopus citations


    Insulin-like growth factor binding protein (IGFBP) gene expression and IGFBP secretion were investigated in a retinoic acid (RA)-resistant subline (RROI) of MCF-7 human breast carcinoma cells. Our results demonstrate that RRO-I cells constitutively secrete higher levels of IGFBP-3 and IGFBP-5. In addition, we found that a 5-fold increase in IGFBP-5 mRNA levels observed in RRO-I cells, which eventually leads to a similar increase in the secreted levels of IGFBP-5, was partly due to an increase in the stability of IGFBP-5 mRNA. Actinomycin D and cycloheximide differentially stabilized IGFBP-5 mRNA in MCF-7 cells but not in RRO-I cells, indicating a difference in the control of IGFBP-5 gene regulation at the level of mRNA stability in these cell lines.

    Original languageEnglish (US)
    Pages (from-to)1122-1130
    Number of pages9
    JournalBiochemical and Biophysical Research Communications
    Issue number3
    StatePublished - Nov 16 1992


    ASJC Scopus subject areas

    • Biophysics
    • Biochemistry
    • Molecular Biology
    • Cell Biology

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