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).


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.


CONCLUSIONS
These findings suggest that Src inhibition by saracatinib may reduce the metastatic activity of tumor cells.
Department of Radiation Oncology, 2033 Mowry Rd Rm 485E, Gainesville, FL 32610, USA.
Meiyu
M
Dong
Lori
L
Rice
Sharon
S
Lepler
Christine
C
Pampo
Dietmar W
DW
Siemann
D000818:Animals; D017209:Apoptosis; D052117:Benzodioxoles / Q000494:pharmacology*; D015153:Blotting, Western; D002448:Cell Adhesion; D002453:Cell Cycle; D002465:Cell Movement; D049109:Cell Proliferation; D004195:Disease Models, Animal; D005260:Female; D005354:Fibrosarcoma / Q000188:drug therapy* / Q000473:pathology; D005455:Fluorescent Antibody Technique; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000556:secondary*; D051379:Mice; D008809:Mice, Inbred C3H; D010766:Phosphorylation; D011799:Quinazolines / Q000494:pharmacology*; D012513:Sarcoma, Experimental / Q000188:drug therapy / Q000473:pathology; D015996:Survival Rate; D014407:Tumor Cells, Cultured; D019061:src-Family Kinases / Q000037:antagonists & inhibitors*
D052117:Benzodioxoles; D011799:Quinazolines; C515233:saracatinib; D051417:Focal Adhesion Kinase 1; C496051:Ptk2 protein, mouse; D019061:src-Family Kinases