Disintegrin-Like Peptides Derived from Naturally-Occurring Proteins: A Proposed Adjunct Treatment for Cancer Therapy: A Commentary

Disintegrins constitute a group of small proteins or peptides (45-85 amino acids) that function as natural antagonists of integrin receptor-dependent cell activities. The integrins themselves comprise a superfamily of hetero-dimeric (alpha and beta chains) transmembrane cell surface receptors whose functions include cell adhesion, growth, migration, and angiogenesis. In contrast, the disintegrins comprise groups of two types of molecules, namely, a) short proteins or peptides comprising insect and animal venoms; and b) intrinsic sub domain sequence fragments or short motifs present on large mammalian metalloprotease enzymes. Certain disintegrins bind specifically to tri-amino acid sequences (RGD, LGD etc) located on integrins beta-1 and beta-3 chains of the hetero complex receptors. Binding at such sites can inhibit or block cell migration, angiogenesis, metastasis, and platelet aggregation. Recently, small disintegrin-like peptides from naturally-occurring proteins have likewise been reported to inhibit growth and adhesion functions associated with integrin-dependent cell activities. The present report describes examples of such disintegrin-like peptides and provides support for their proposed use in adjunct cancer therapy.