Adapalene

Adapalene is a synthetic retinoid and an agonist of retinoic acid receptors (RARs; K_ds = 1,100, 34, and 130 nM for RARα, RARβ, and RARγ, respectively).^1,2,3,4,5 It inhibits growth and differentiation of sebocytes in a concentration-dependent manner in primary rat preputial cell culture. Adapalene (10 μM) completely inhibits the activity of soybean 15-lipoxygenase (15-LOX) in an enzyme assay and inhibits the 5- and 15-LOX pathways in human blood polymorphonuclear leukocytes (PMNs).² It reduces the protein levels of toll-like receptor 2 (TLR2) and IL-10 in skin explants isolated from patients with acne and healthy controls in a concentration-dependent manner but increases the expression of the antigen-presenting protein CD1d in acne skin explants while decreasing it in control explants.³ It inhibits inflammation in rodent models of ear edema induced by arachidonic acid and carrageenan-induced paw edema.² Adapalene (100 μM) also induces apoptosis and inhibits proliferation of CC-531, HT-29, and LoVo colon cancer cells and reduces tumor growth in a DLD-1 colon cancer nude mouse xenograft model in a dose-dependent manner.^5,4 Formulations containing adapalene have been used in the treatment of acne vulgaris.

WARNING This product is not for human or veterinary use.

1. Kim, M.J., Ciletti, N., Michel, S., et al. The role of specific retinoid receptors in sebocyte growth and differentiation in culture. J. Invest. Dermatol. 114(2), 349-353 (2000).

2. Hensby, C., Cavey, D., Bouclier, M., et al. The in vivo and in vitro anti-inflammatory activity of CD271: A new retinoid-like modulator of cell differentiation. Agents Actions 29(1-2), 56-58 (1990).

3. Tenaud, I., Khammari, A., and Dreno, B. In vitro modulation of TLR-2, CD1d and IL-10 by adapalene on normal human skin and acne inflammatory lesions. Exp. Dermatol. 16(6), 500-506 (2007).

4. Ocker, M., Herold, C., Ganslmayer, M., et al. The synthetic retinoid adapalene inhibits proliferation and induces apoptosis in colorectal cancer cells in vitro. Int. J. Cancer 107(3), 453-459 (2003).

5. Shi, X.-N., Li, H., Yao, H., et al. Adapalene inhibits the activity of cyclin-dependent kinase 2 in colorectal carcinoma. Mol. Med. Rep. 12(5), 6501-6508 (2015).