CD 437

CD 437 is a selective agonist of RARγ [1].

Retinoic acid receptor gamma (RAR-γ) is a nuclear receptor that is activated by 9-cis retinoic acid and all-trans retinoic acid. RAR-γ also functions as a transcription factor.

CD 437 is a selective RARγ agonist. In tumor cells, CD437 induced RAR-γ-dependent differentiation and apoptosis. Also, CD437 induced DNA adduct formation and p53-independent DNA damage response [1]. In DU145 human prostate cancer cells, CD437 rapidly reduced IκBα and increased nuclear translocation of the NF-κB subunit p65. Also, CD437 increased the DNA-binding activity of NF-κB and induced DR4 expression and apoptosis [2]. In human melanoma A375 cells, CD437 induced apoptosis, which was mediated by the activation of NF-κB and RIG-I (retinoic acid inducible gene I) pathway [3]. In human osteosarcoma cells, CD437 activated c-Jun N-terminal kinase 1 (JNK1) through the upregulation of thioredoxin-binding protein 2 (TBP2) and induced apoptosis. Also, CD437 induced TBP2 mRNA expression by recruitment of ETS1 transcription factor [4].

References:
[1].  Zhao X, Spanjaard RA. The apoptotic action of the retinoid CD437/AHPN: diverse effects, common basis. J Biomed Sci, 2003, 10(1): 44-49.
[2].  Jin F, Liu X, Zhou Z, et al. Activation of nuclear factor-kappaB contributes to induction of death receptors and apoptosis by the synthetic retinoid CD437 in DU145 human prostate cancer cells. Cancer Res, 2005, 65(14): 6354-6363.
[3].  Pan M, Geng S, Xiao S, et al. Apoptosis induced by synthetic retinoic acid CD437 on human melanoma A375 cells involves RIG-I pathway. Arch Dermatol Res, 2009, 301(1): 15-20.
[4].  Hashiguchi K, Tsuchiya H, Tomita A, et al. Involvement of ETS1 in thioredoxin-binding protein 2 transcription induced by a synthetic retinoid CD437 in human osteosarcoma cells. Biochem Biophys Res Commun, 2010, 391(1): 621-626.

Rapid and efficient reprogramming of somatic cells to induced pluripotent stem cells by retinoic acid receptor gamma and liver receptor homolog 1.[Pubmed:21990348]

Proc Natl Acad Sci U S A. 2011 Nov 8;108(45):18283-8.

Somatic cells can be reprogrammed to induced pluripotent stem cells (iPSCs) by expressing four transcription factors: Oct4, Sox2, Klf4, and c-Myc. Here we report that enhancing RA signaling by expressing RA receptors (RARs) or by RA agonists profoundly promoted reprogramming, but inhibiting it using a RAR-alpha dominant-negative form completely blocked it. Coexpressing Rarg (RAR-gamma) and Lrh-1 (liver receptor homologue 1; Nr5a2) with the four factors greatly accelerated reprogramming so that reprogramming of mouse embryonic fibroblast cells to ground-state iPSCs requires only 4 d induction of these six factors. The six-factor combination readily reprogrammed primary human neonatal and adult fibroblast cells to exogenous factor-independent iPSCs, which resembled ground-state mouse ES cells in growth properties, gene expression, and signaling dependency. Our findings demonstrate that signaling through RARs has critical roles in molecular reprogramming and that the synergistic interaction between Rarg and Lrh1 directs reprogramming toward ground-state pluripotency. The human iPSCs described here should facilitate functional analysis of the human genome.

The apoptotic action of the retinoid CD437/AHPN: diverse effects, common basis.[Pubmed:12566985]

J Biomed Sci. 2003 Jan-Feb;10(1):44-9.

Retinoids, such as all-TRANS-retinoic acid (RA), have found applications in several different types of (cancer) therapies. The synthetic retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437 or AHPN), an RA receptor (RAR)gamma agonist, not only induces RARgamma-dependent differentiation, but in contrast to RA, it also induces RARgamma-independent apoptosis in many tumor cells. This observation makes this and similar new retinoids very interesting from a clinical perspective. Several genes have been associated with CD437/AHPN-mediated apoptosis, but the multiple activities of this compound and the apparent cell-type-specific responses to treatment have made it difficult to discern a common biochemical basis for the mechanism of its apoptotic action. In this brief review, we present a model which links all CD437/AHPN-associated apoptotic effects. CD437/AHPN rapidly induces DNA adduct formation through an as-yet unknown reaction which is independent of cell type. This is followed by a cell-type-specific, largely p53-independent DNA damage response which can result in engagement of multiple cell death pathways and activation of caspases as a common endpoint. At the same time, the RARgamma-dependent pathway leads to regulation of differentiation-associated, cell-type-specific genes. CD437/AHPN, with its simultaneous differentiation and apoptosis-inducing activities, is a good prototype for new drugs which may be clinically more efficacious than those with a single activity.