EXPRESSION OF COFACTORS (SMRT AND TRIP-1) FOR RETINOIC ACID RECEPTORSIN HUMAN NEUROECTODERMAL CELL-LINES

Retinoic acid (RA) induces growth inhibition, differentiation or cell death in many human neuroblastoma cell lines. Recently, the transactiv ation activity of nuclear retinoids receptors has been shown to be mod ulated through physical association with other proteins that act as co -activators or as co-repressors. We investigated the expression of the co-repressor (SMRT) and co-activator (Trip 1) for retinoid and thyroi d-hormone receptors in several neuroectodermal tumour cell lines, and its modulation by all-trans-retinoic acid, as well as by synthetic ago nists, for RAR alpha, RAR beta, RAR gamma and RXR. We demonstrate that (i) SMRT and Trip-1 mRNAs are expressed in many human neuroblastoma a nd melanoma cell lines in basal conditions, (ii) SMRT mRNA expression in human neuroblastoma cell line SK-N-BE(2) increases after 48 hours o f incubation with 1 mu M RA and RARs specific agonists, (iii) Trip-1 m RNA in the same cell line does not change during incubation with RA or selective synthetic agonists for RARs and RXR. (C) 1997 Academic Pres s.