Action of the Disintegrin Contortrostatin on Breast Cancer Cell Primary Cultures

Integrins mediate cell adhesion to the extracellular matrix (ECM). In particular, integrin alphavbeta3 recognizes the RGD motif as a ligand-binding site on various extracellular molecules of the extracellular matrix. Integrin aphavbeta3 has been associated with high malignant potential in breast cancer cells, and has signalized the onset of widespread metastasis. In recent years, several antagonists of integrin alphavbeta3, including snake venom disintegrins, have been used as potential anti-cancer agents. In the present work, the effect of contortrostatin, a disintegrin isolated from the venom of the snake Agkistrodon contortrix, was studied on primary cultures of human breast cancer cell. Scanning and transmission electron microscopy were employed in order to examine alterations in cell morphology and fluorescent microscopy and visualize changes in distribution of integrin alphavbeta3 and talin. Fluorescent localization of caspase 8 was made in order to visualize any sign of proapoptotosis and western immunoblotting of integrin, talin and annexin was undertaken in order to identify changes. The results suggest that the snake venom contortrostatin seriously affects cell morphology, adhesion and mobility and induces breast cancer cells to apoptosis.