Anti-metastatic Effect of Repeated Cyclic- GRGDSPA Peptide Produced by Intein Protein Trans-splicing on Murine B16 Melanoma Cells

Background and objective Metastasis is one of the most important causes of mortality in tumor. The pathological process of metastasis includes several sequential steps as following： tumor cells release from the primary site and get invasion into the surrounding tissues; enter into vascular or lymphatic circulation; transit in the circulation; arrest in the capillary bed of a distant organ; extravasate from circulation; grow at apparently selective sites which are distant from the primary site. In these steps, ）ust few tumor cells in a primary site can completely overcome for achieving metastasis. During these complex process of metastasis, tumor cells encounter a variety of host cells such as platelets and endothelial cells, and extracellular matrix （ECM） which is the immediate surrounding of fibroblasts and tumor cells. Inter- actions of both tumor cells and host tissue cells with the ECM play a pivotal role in tumor biology, such as tumor cell growth, any step of the metastatic cascade and angiogenesis. The