Impact of the Src inhibitor saracatinib on the metastatic phenotype of a fibrosarcoma (KHT) tumor model.

Background: Src, a non-receptor tyrosine kinase frequently overexpressed and highly activated in malignancies, has been associated with a poor patient prognosis. The aim of the present studies was to examine the impact of an Src inhibitor (saracatinib) on a highly metastatic murine sarcoma cell line (KHT).
Materials and Methods: Phosphorylation of Src and downstream effectors was determined using Western immunoblotting. Cell cycle was analyzed by flow cytometry using propidium iodide DNA staining, migration and invasion in modified Boyden chambers, activated MMP-9 by gel zymography, and visualization of pSrc and pFAK by confocal immunofluorescence. The number of KHT lung nodules in saracatinib-treated mice was compared to controls.
Results: Saracatinib inhibited major pathways in the metastatic cascade in vitro, including Src and FAK activation. Functions required for metastasis, such as migration and invasion, were reduced when cells were exposed to 0.5 μM and 1.0 μM saracatinib, respectively (p<0.0001). Pretreatment of KHT cells with either 1 μM or 5 μM saracatinib prior to tail vein injection decreased lung colonies in mice from 13.0 to 5.0 (p<0.05) and less than 1.0 (p<0.01), respectively.
Conclusion: These findings suggest that Src inhibition by saracatinib may reduce the metastatic activity of tumor cells.