9-cis retinoic acid induces insulin-like growth factor binding protein-3 through DR-8 retinoic acid responsive elements.
Retinoic acids, which have shown potential chemopreventive and therapeutic activities for several neoplastic diseases in vitro, modulate the growth-promoting and anti-apoptotic activities of insulin-like growth factors (IGFs), in part by influencing the expression of insulin-like growth factor binding protein-3 (IGFBP-3). This study sought to investigate the effect of 9-cis retinoic acid (9cRA) on the expression of IGFBP-3 and the underlying mechanisms involving retinoic acid receptor-beta (RAR-beta). The pharmacologic activity of 9cRA was characterized by monitoring target modulation as well as by evaluating the underlying mechanisms in NSCLC cells. Treatment of 9cRA inhibited proliferation of a part of NSCLC cell lines including H460 cells in clinically-achievable concentrations and induced IGFBP-3 expression in dose- and time-dependent manners. Transient transfection with a reporter constructs driven by the human IGFBP-3 gene promoter indicated that 9cRA induces gene expression via the -534 to -445 region (relative to translation start site) of the IGFBP-3 promoter. Unilateral deletion and site-directed mutagenesis identified a retinoic acid responsive element (RARE), a direct repeat of two GGGTCA-related hexanucleotides separated by just 8 bp (DR-8-type response element). A cotransfection assay with a RAR-beta expression vector potentiated (and with siRNA for RAR-beta, diminished) the effect of 9cRA on IGFBP-3 expression. IGFBP-3 gene expression by 9cRA is mediated by a distinct DR-8 RARE located in the proximal region of the IGFBP promoter and involves the RAR-beta, a putative tumor suppressor in NSCLC.
Chang
Yoon Soo
YS
Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
Cho
Jae Yong
JY
Cho
Hyun A
HA
Kim
Hyung Jung
HJ
Chang
Joon
J
Ahn
Chul Min
CM
Kim
Sung Kyu
SK
Kim
Se Kyu
SK
D000077556:Alitretinoin; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D055513:Connective Tissue Growth Factor; D017931:DNA Primers; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics*; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000235:genetics*; D018975:Insulin-Like Growth Factor Binding Protein 5 / Q000235:genetics*; D018976:Insulin-Like Growth Factor Binding Protein 6 / Q000235:genetics*; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics*; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics*; D010957:Plasmids; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014212:Tretinoin / Q000502:physiology*
C526317:CCN2 protein, human; D017931:DNA Primers; D017874:Immediate-Early Proteins; D018972:Insulin-Like Growth Factor Binding Protein 3; D018974:Insulin-Like Growth Factor Binding Protein 4; D018975:Insulin-Like Growth Factor Binding Protein 5; D018976:Insulin-Like Growth Factor Binding Protein 6; D018969:Insulin-Like Growth Factor Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; C102529:insulin-like growth factor binding protein-related protein 1; D055513:Connective Tissue Growth Factor; D000077556:Alitretinoin; D014212:Tretinoin