Enhanced expression of type IV collagen-binding protein (p29) in Fyn-transfected murine fibrosarcoma cells.
We investigated the mechanism of the enhancement of metastatic potential induced by transfection of the fyn gene, a member of the src family. We employed two murine fyn cDNA-transfected clones, ML-SN1 and ML-SN2, which were previously established from an ML-01 low-metastatic clone of Meth A sarcoma of BALB / c mice and were proven to have higher metastatic ability than ML-01 and the mock-transfected clone ML-MT-neo (Takayama et al., 1993). Our present investigation revealed that the two transfectants showed higher metastatic ability and higher rates of adherence to type IV collagen than ML-MT-neo. However, no difference was found in in vitro or in vivo growth rates, attachment to laminin or endothelial cells or cell motility through a reconstituted basement membrane. Analysis of surface membrane proteins labeled with (125)I on SDS-PAGE showed that a 29 kD band specifically bound to type IV collagen-coupled beads was more intense in ML-SN2 than in ML-MT-neo. Genistein, a protein tyrosine kinase inhibitor, dramatically reduced protein tyrosine kinase (PTK) activity of ML-SN2 in a dose-dependent fashion, corresponding to the reduction of adhesiveness to type IV collagen. The expression of the type IV collagen-binding protein (p29) of ML-SN2 was also reduced significantly by genistein treatment. These results suggested that the fyn product in Meth A cells augments the expression of a type IV collagen-binding protein through elevation of the PTK activity of the membrane fraction and thus facilitates the metastasis of Meth A.
Koike
Kazuhiko
K
The Fourth Department of Internal Medicine, Sapporo Medical University School of Medicine, South-1 West-16, Chuo-ku, Sapporo 060-8543, Japan.
Kogawa
Katsuhisa
K
Takayama
Tetsuji
T
Yoshizaki
Naohito
N
Muramatsu
Hirohito
H
Nakamura
Kiminori
K
Sakamaki
Sumio
S
Niitsu
Yoshiro
Y
D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis*; D015815:Cell Adhesion Molecules / Q000096:biosynthesis*; D002465:Cell Movement; D024141:Collagen Type IV / Q000378:metabolism*; D005260:Female; D005353:Fibronectins / Q000378:metabolism; D005354:Fibrosarcoma / Q000378:metabolism* / Q000473:pathology / Q000556:secondary; D019833:Genistein / Q000494:pharmacology; D019012:Integrin beta1 / Q000502:physiology; D007797:Laminin / Q000378:metabolism; D008175:Lung Neoplasms / Q000556:secondary; D051379:Mice; D008807:Mice, Inbred BALB C; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D051076:Proto-Oncogene Proteins c-fyn; D012513:Sarcoma, Experimental / Q000378:metabolism / Q000473:pathology / Q000556:secondary; D014162:Transfection; D014407:Tumor Cells, Cultured
D002352:Carrier Proteins; D015815:Cell Adhesion Molecules; D024141:Collagen Type IV; D005353:Fibronectins; D019012:Integrin beta1; D007797:Laminin; D011518:Proto-Oncogene Proteins; D019833:Genistein; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn