In vivo biological activity of retinoids partially correlates to their affinity to recombinant retinoic‐acid receptor α and recombinant‐cellular retinoic‐acid‐binding protein I

Abstract

Several known and some new retinoids were synthesized and their in vivo activity was investigated by an assay, based on induction of alkaline phosphatase in P19 teratocarcinoma cells, human prostate carcinoma cells and primary cultures of neonatal rat heart cells. The assay used in this study was found to be reproducible and useful for rapid screening of retinoids for biological activity. Two newly synthesized compounds exhibit high biological activity. The biological potency of the compounds was compared to their ability to bind to recombinant retinoic-acid receptor a and to cellular retinoic-acid-binding protein I determined by Charsorb-binding assay. mRNA of both retinoic-acid-binding proteins could be detected in the three cell lines investigated. As expected from the number of different retinoic-acid receptors, the results suggest that retinoids do not need to bind retinoic-acid receptor a nor cellular retinoic-acid-binding protein I in order to exhibit biological activity, but most retinoids investigated show a clear correlation between binding to these proteins and their biological activity.

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“…Retinoic acid is able to induce the increase of ALP activity in a variety of cells (Gianni et al, 1991(Gianni et al, , 1993a(Gianni et al, , 1993bScheibe et al, 1991;Keidel et al, 1993;San Miguel et al, 1998. Among all these cells studied, the induction of ALP was observed at least 48 hr after the treatment with retinoic acid, identical with present results with ST2 cells (Figure 5B).…”

Analysis of the Effects of CRABP I Expression on the RA-Induced Transcription Mediated by Retinoid Receptors

“…However, the recently obtained evidence that mutant mice lacking both CRABP I and CRABP II are indistinguishable from wild-type mice in their physiology and response to the exposure to excess RA indicates that CRABPs are not essential components of the RA-signaling pathway (Gorry et al, 1994;Lampron et al, 1995). Support for such a conclusion also comes from the evidence that some cell lines lacking CRABP I still retain the ability to support the RAinduced cell differentiation (Jetten et al, 1987) and that there is a lack of complete correlation between the ability of the retinoids to bind CRABP and their biological activity ( Tamura et al, 1990;Willhite et al, 1992;Asselineau et al, 1992;Keidel et al, 1993;Sass et al, 1995). Yet, the evolutionary conservation of CRABPs among various species and their ability to bind RA suggest an important role for these proteins in the regulation of the intracellular concentration of this retinoid.…”

Inhibition of Papilloma Formation by Analogues of 7,8-Dihydroretinoic Acid

“…2,4-Bis(1,1-dimethylethyl)benzenamine was prepared as described by Keidel et al . from the corresponding nitrobenzene . Compound 12e was obtained from the benzenamine and 17 as described for 12a except that the reaction mixture was boiled under reflux during 6.5 h. The solid obtained by concentrating the reaction mixture in vacuo was triturated with small amounts of acetonitrile, and the residue (57% yield) was recrystallized from the same solvent: HPLC (7:3 MeCN−1% aq NH 4 OAc, 340 nm), 99.5%; UV (EtOH) λ max 314 nm (ε 47000); IR (KBr disk, strong bands cm -1 ) 3255 (broad), 2961, 1721, 1648, 1601, 1507, 1361, 1290, 1244, 1237, 1162, 963; 1 H NMR (CDCl 3 ) δ 7.53 (d, 1H, H 6‘, J 5 ‘ ,6 ‘ = 8.2 Hz), 7.46 (bs, 1H, N H ), 7.43 (d, 1H, H 3‘, J 3 ‘ ,5 ‘ = 2.2 Hz), 7.27 (dd, 1H, H 5‘, J 3 ‘ ,5 ‘ = 2.2 Hz, J 5 ‘ ,6 ‘ = 8.2 Hz), 7.15 (bd, 1H, H 10, J 10,11 = 11.4 Hz), 6.90 (dd, 1H, H 11, J 10,11 = 11.4 Hz, J 11,12 = 15.0 Hz), 6.55 (d, 1H, H 12, J 11,12 = 15.0 Hz), 5.90 (bs, 1H, H 14), 3.73 (s, 3H, COOC H 3 ), 2.37 (d, 3H, 13C H 3 , J 13-CH3,14 = 1.1 Hz), 2.18 (s, 3H, 9C H 3 ), 1.43 (s, 9H, 2‘C(C H 3 ) 3 ), 1.32 (s, 9H, 4‘C(C H 3 ) 3 ).…”

“…2,4-Bis(1,1-dimethylethyl)-6-methylbenzenamine was prepared as described by Keidel et al . from the corresponding nitrobenzene . Ester-acid 14 (40 mg, 0.19 mmol) was suspended in benzene (5 mL), phosphorus tribromide (40 mg, 0.15 mmol) was added, and the mixture was warmed to effect solution and was stirred during 1.5 h. A solution of the benzenamine (40 mg, 0.18 mmol) in DMF (3 mL) was added to the acid bromide ( 18 ) solution, and the resulting mixture was stirred at room temperature during 2 h and at 50 °C during 2 h. The reaction mixture was poured into water, the aqueous mixture was extracted with ether, and the ether layer was washed with brine, dried (MgSO 4 ), and concentrated to an oil that crystallized (yield 38 mg).…”

“…The procedure was like that for 12a except that the reaction mixture, under nitrogen and with a reflux condenser, was heated at 70 °C during 6 h and at 85 °C during 3 h and then was maintained in the range of 70-85 °C overnight. The mixture was concentrated in vacuo to a semisolid that was triturated twice with small portions 25 from the corresponding nitrobenzene. 26 Compound 12e was obtained from the benzenamine and 17 as described for 12a except that the reaction mixture was boiled under reflux during 6.5 h. The solid obtained by concentrating the reaction mixture in vacuo was triturated with small amounts of acetonitrile, and the residue (57% yield) was recrystallized from the same solvent: HPLC (7:3 MeCN-1% aq NH4OAc, 340 nm), 99.5%; UV (EtOH) λmax 314 nm ( 47000); IR (KBr disk, strong bands cm -1 ) 3255 (broad), 2961, 1721, 1648, 1601, 1507, 1361, 1290, 1244, 1237, 1162, 25 from the corresponding nitrobenzene.…”