AM580 is a selective agonist of retinoic acid receptor α (RARα) with IC50 and EC50 values of 8 nM and 0.36 nM, respectively [1].

RARα is ubiquitously expressed. It is important for retinoid response during growth and differentiation of epithelial cells. RARα have functions in the inhibition of cell and mammary tumour growth, increase in tumour latency, induction of cell cycle arrest, stimulation of cell death, and up-regulation of RARα and RARγ mRNA [1, 2]. In addition, RARα is involved in the production of human T cell activation and type 2 cytokine [3].

In SK-BR-3 and T47D breast cancer cell lines, treatment with AM580 at concentrations of 1 nM and 10 nM for 7 days resulted in the decrease in the number of cells [1]. AM580 at a concentration of 200 nM, enhanced the anti-proliferative effect shown by the knockdown of RAR-γ in MCF-10A breast epithelial and MCF-7 cell lines [2].

When 200 nM AM580 was applied to MMTV-Myc female mice for 96 hours, this led to impaired cell proliferation capacity. Furthermore, combination of AM580 with 100 nM CD437 and SR11253 resulted in strong growth inhibition, clearly demonstrating the ability of AM580 to reduce the tumour growth in MMTV-Myc tumour model [2].

References:
[1].  Schneider S, Offterdinger M, Huber H, et al. Activation of Retinoic Acid Receptor a Is Sufficient for Full Induction of Retinoid Responses in SK-BR-3 and T47D Human Breast Cancer Cells. Cancer Res, 2000, 60(19):5479-87.
[2].  Bosch A, Bertran S, Lu Y, et al. Reversal by RARa agonist Am580 of c-Myc induced imbalance in RARa/RARγ expression during MMTV-Myctumorigenesis. Breast Cancer Res, 2012, 14(4):R121.
[3].  Dawson H, Collins G, Pyle R, et al. The Retinoic Acid Receptor-α mediates human T-cell activation and Th2 cytokine and chemokine production. BMC Immunol, 2008, 9:16.