title: 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.
abstract: 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.
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism*; D002277:Carcinoma / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D003609:Dactinomycin / Q000494:pharmacology; D004351:Drug Resistance; D015972:Gene Expression Regulation, Neoplastic; D018969:Insulin-Like Growth Factor Binding Proteins; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism; D013002:Somatomedins / Q000378:metabolism; D013997:Time Factors; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D013002:Somatomedins; D003609:Dactinomycin; D014212:Tretinoin