c-Src kinase activity is required for hepatocyte growth factor-induced motility and anchorage-independent growth of mammary carcinoma cells.
Overexpression and amplification of hepatocyte growth factor (HGF) receptor (Met) have been detected in many types of human cancers, suggesting a critical role for Met in growth and development of malignant cells. However, the molecular mechanism by which Met contributes to tumorigenesis is not well known. The tyrosine kinase c-Src has been implicated as a modulator of cell proliferation, spreading, and migration; these functions are also regulated by Met. To explore whether c-Src kinase is involved in HGF-induced cell growth, a mouse mammary carcinoma cell line (SP1) that co-expresses HGF and Met and a nonmalignant epithelial cell line (Mv1Lu) that expresses Met but not HGF were used. In this study, we have shown that c-Src kinase activity is constitutively elevated in SP1 cells and is induced in response to HGF in Mv1Lu cells. In addition, c-Src kinase associates with Met following stimulation with HGF. The enhanced activity of c-Src kinase also correlates with its ability to associate with Met. Expression of a dominant negative double mutant of c-Src (SRC-RF), lacking both kinase activity (K295R) and a regulatory tyrosine residue (Y527F), in SP1 cells significantly reduced c-Src kinase activity and strongly blocked HGF-induced motility and colony growth in soft agar. In contrast, expression of the dominant negative c-Src mutant had no effect on HGF-induced cell proliferation on plastic. Taken together, our data strongly suggest that HGF-induced association of c-Src with Met and c-Src activation play a critical role in HGF-induced cell motility and anchorage-independent growth of mammary carcinomas and further support the notion that the presence of paracrine and autocrine HGF loops contributes significantly to the transformed phenotype of carcinoma cells.
Rahimi
N
N
Department of Pathology, Cancer Research Laboratories, Queen's University, Kingston, Ontario K7L 3N6, Canada.
Hung
W
W
Tremblay
E
E
Saulnier
R
R
Elliott
B
B
D000818:Animals; D000081247:CSK Tyrosine-Protein Kinase; D002448:Cell Adhesion; D002455:Cell Division / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D017228:Hepatocyte Growth Factor / Q000502:physiology*; D008325:Mammary Neoplasms, Experimental / Q000201:enzymology / Q000473:pathology*; D051379:Mice; D010641:Phenotype; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism; D014407:Tumor Cells, Cultured; D019061:src-Family Kinases
D017228:Hepatocyte Growth Factor; D011505:Protein-Tyrosine Kinases; D019859:Proto-Oncogene Proteins c-met; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human