Competitive PCR demonstrates that 9-cis retinoic acid induces cellular retinoic acid-binding protein-II more efficiently than all-trans retinoic acid in human osteosarcoma cells.
Cellular retinoic acid-binding proteins (CRABPs) are thought to play a key role in the regulation of the levels of retinoic acid (RA) available to interact with the nuclear receptors. In this study we have used reverse transcription (RT) and competitive polymerase chain reaction (cPCR) to investigate the effects of RA on CRABP-II expression levels in the human osteosarcoma cell line MG-63. Two different isomers of RA, all-trans (at) and 9-cis RA, were chosen since at-RA but not 9-cis RA binds to CRABP-II. Cells were treated with 10(-6) M at-RA or 9-cis RA for 24 h. Following RNA preparation and RT, cPCR was performed using constructed internal standards for CRABP-II and beta-actin. While no change occurred in the beta-actin control, an approximate two-fold increase of CRABP-II mRNA levels was seen in cells treated with at-RA and at least a four-fold increase with 9-cis RA. Thus, although 9-cis RA does not bind to CRABP-II, it induces CRABP-II expression more efficiently than at-RA in human osteosarcoma cells.
Melhus
H
H
Department of Internal Medicine, University Hospital, Uppsala, Sweden.
Gobl
A
A
Ljunghall
S
S
D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D008969:Molecular Sequence Data; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism; D012516:Osteosarcoma / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D018168:Receptors, Retinoic Acid / Q000096:biosynthesis* / Q000235:genetics; D013237:Stereoisomerism; D014212:Tretinoin / Q000737:chemistry / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D017931:DNA Primers; D018076:DNA, Complementary; D018168:Receptors, Retinoic Acid; C082928:retinoic acid binding protein II, cellular; D014212:Tretinoin