CD 3254

CD3254 is a potent and selective agonist of Retinoid X receptors (RXRα).

Retinoid X receptors (RXRs) are nuclear receptors that act as ligand-dependent transcription factors and function as the homodimer or as heterodimers with other nuclear receptors, such as retinoic acid receptors (RARs), peroxisome proliferator-activated receptors (PPARs), or liver X receptors (LXRs). RXR plays essential roles in the regulation of glucose metabolism, lipid metabolism and immune response. Retinoid X receptors (RXRs) contains three family members including RARα, RARβ or RARγ receptors. RXRα belongs to the NR2B nuclear receptor family and primarily expressed in the liver, intestines, kidneys, and epidermis.

CD3254 and its’ analogue bexarotene have been reported as a treatment for cutaneous T-cell lymphoma (CTCL), despite the fact that treatment with CD3254 can evoke reactions by disturbing other RXR-heterodimer receptor pathways. Of the seven displayed novel exacerbates, all analogs animate RXR-controlled translation in mammalian 2 hybrid and RXRE-interceded tests, have equivalent or hoisted natural action in view of EC50 profiles, and hold comparative or enhanced apoptotic movement in CTCL assays contrasted with CD3254. Every single novel compound show selectivity for RXR and insignificant hybrid onto the retinoic corrosive receptor (RAR) contrasted with all-trans-retinoic corrosive, with select analogs likewise decreasing hindrance of other RXR-subordinate pathways (e.g., VDR-RXR) [1].

In vivo, CD3254 induced the phenotypes of malformations after 5 days exposure at low concentration (20 μg/l) to those after the 1st d exposure at high concentrations (50 and 100 μg/L) [2].

References:
Modeling, synthesis, and biological evaluation of potential retinoid X receptor (RXR) selective agonists: novel analogues of 4-[1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)ethynyl]benzoic acid (bexarotene) and (E)-3-(3-(1,2,3,4-tetrahydro-1,1,4,4,6-pentamethylnaphthalen-7-yl)-4-hydroxyphenyl)acrylic acid (CD3254).  J Med Chem. 2013 Nov 14;56(21):8432-54. doi: 10.1021/jm4008517. Epub 2013 Nov 1.
Divergent teratogenicity of agonists of retinoid X receptors in embryos of zebrafish (Danio rerio).  Ecotoxicology. 2012 Jul;21(5):1465-75. doi: 10.1007/s10646-012-0900-9. Epub 2012 Apr 10.

Activation of RXR-PPAR heterodimers by organotin environmental endocrine disruptors.[Pubmed:19270714]

EMBO Rep. 2009 Apr;10(4):367-73.

The nuclear receptor retinoid X receptor-alpha (RXR-alpha)-peroxisome proliferator-activated receptor-gamma (PPAR-gamma) heterodimer was recently reported to have a crucial function in mediating the deleterious effects of organotin compounds, which are ubiquitous environmental contaminants. However, because organotins are unrelated to known RXR-alpha and PPAR-gamma ligands, the mechanism by which these compounds bind to and activate the RXR-alpha-PPAR-gamma heterodimer at nanomolar concentrations has remained elusive. Here, we show that tributyltin (TBT) activates all three RXR-PPAR-alpha, -gamma, -delta heterodimers, primarily through its interaction with RXR. In addition, the 1.9 A resolution structure of the RXR-alpha ligand-binding domain in complex with TBT shows a covalent bond between the tin atom and residue Cys 432 of helix H11. This interaction largely accounts for the high binding affinity of TBT, which only partly occupies the RXR-alpha ligand-binding pocket. Our data allow an understanding of the binding and activation properties of the various organotins and suggest a mechanism by which these tin compounds could affect other nuclear receptor signalling pathways.

Characterization of the interaction between retinoic acid receptor/retinoid X receptor (RAR/RXR) heterodimers and transcriptional coactivators through structural and fluorescence anisotropy studies.[Pubmed:15528208]

J Biol Chem. 2005 Jan 14;280(2):1625-33.

Retinoid receptors (RARs and RXRs) are ligand-activated transcription factors that regulate the transcription of target genes by recruiting coregulator complexes at cognate promoters. To understand the effects of heterodimerization and ligand binding on coactivator recruitment, we solved the crystal structure of the complex between the RARbeta/RXRalpha ligand-binding domain heterodimer, its 9-cis retinoic acid ligand, and an LXXLL-containing peptide (termed NR box 2) derived from the nuclear receptor interaction domain (NID) of the TRAP220 coactivator. In parallel, we measured the binding affinities of the isolated NR box 2 peptide or the full-length NID of the coactivator SRC-1 for retinoid receptors in the presence of various types of ligands. Our correlative analysis of three-dimensional structures and fluorescence data reveals that heterodimerization does not significantly alter the structure of individual subunits or their intrinsic capacity to interact with NR box 2. Similarly, we show that the ability of a protomer to recruit NR box 2 does not vary as a function of the ligand binding status of the partner receptor. In contrast, the strength of the overall association between the heterodimer and the full-length SRC-1 NID is dictated by the combinatorial action of RAR and RXR ligands, the simultaneous presence of the two receptor agonists being required for highest binding affinity. We identified an LXXLL peptide-driven mechanism by which the concerted reorientation of three phenylalanine side chains generates an "aromatic clamp" that locks the RXR activation helix H12 in the transcriptionally active conformation. Finally, we show how variations of helix H11-ligand interactions can alter the communication pathway linking helices H11, H12, and the connecting loop L11-12 to the coactivator-binding site. Together, our results reveal molecular and structural features that impact on the ligand-dependent interaction of the RAR/RXR heterodimer with nuclear receptor coactivators.