RGDS peptide contains the RGD motif which is an antagonist of integrin [1, 2].

Integrins are cell-surface receptors that recognize RGD motifs present in various extracellular matrix proteins such as fibronectin, vitronectin, laminin, fibrinogen, von Willebrand factor, osteopontin, thrombospondin, and collagen as well as in disintegrins. Integrins activation triggers different signals regulating cell adhesion, migration, survival, apoptosis as well as processes such as angiogenesis, thrombosis and osteoporosis [1].

In SK-MEL-110 cells, RGDS at 500 μg/ml significantly inhibited melanoma cells proliferation induced by human fibroblast growth factor-2 (FGF-2). Furthermore, RGDS treatment (48 h, 500 μg/ml) increased the percentage of cells in sub-G₁-phase from 3% (with FGF-2 alone) to 13.2% (with FGF-2 and RGDS), indicating that RGDS might induce apoptosis in melanoma cells, in the presence of FGF-2 [1].

In a guinea pig model of allergic asthma, topical treatment of the airways with intranasally instilled RGDS (2.5 mM, 200 μl) attenuated allergen-induced airway smooth muscle hyperplasia and hypercontractility as well as increased pulmonary expression of smooth muscle myosin heavy chain and the proliferative marker proliferating cell nuclear antigen [2].

References:

[1]. Aguzzi M S, Fortugno P, Giampietri C, et al. Intracellular targets of RGDS peptide in melanoma cells. Molecular Cancer, 2010, 9(84): 1-10.

[2]. Dekkers B G, Bos I S, Gosens R, et al. The integrin-blocking peptide RGDS inhibits airway smooth muscle remodeling in a guinea pig model of allergic asthma. American Journal of Respiratory and Critical Care Medicine, 2010, 181(6): 556-565.