Tumorigenic and metastatic properties of two ras-oncogene transfected rat fibrosarcoma cell lines defective in c-jun.
We here report the spontaneous loss of both homologues of the c-jun gene in two cell lines, isolated after transfection of rat embryo fibroblasts with single ras-oncogenes. These cells lines (designated A14 and B25) grow rapidly in vitro, have transformed morphologies and are invasive through reconstituted basal membranes. Both c-jun defective cell lines were found to be tumorigenic and metastatic in athymic mice. Loss of c-jun was paralleled by a dramatic decrease in interstitial collagenase expression, whereas stromelysin mRNA expression in c-jun- A14 and B25 cells was similar to that observed in c-jun+ transformed cell lines. Transient transfection experiments using reporter plasmids showed that stromelysin promoter activity in A14 cells was severely impaired by a point mutation in the -71 to -65 AP-1 motif, and was inhibited by a Jun dominant negative mutant. Gel mobility shift studies demonstrated the presence of a factor in A14 nuclear extracts capable of binding the stromelysin TRE. This factor bound JunB, JunD and Fos antibodies. Our findings suggest that c-Jun is not required for the tumorigenic and metastatic potential of ras-transformed fibrosarcoma cells, and that AP-1 protein(s) lacking c-Jun are capable of activating the stromelysin gene promoter.
Department of General Oncology, Radiumhemmet, Karolinska Institute and Hospital, Stockholm, Sweden.
H
H
Marshall-Heyman
G
G
Engel
S
S
Ljungdahl
M C
MC
Shoshan
C
C
Svensson
B
B
Wasylyk
S
S
Linder
D000818:Animals; D001665:Binding Sites; D017364:Collagenases / Q000235:genetics; D005354:Fibrosarcoma / Q000235:genetics*; D016758:Genes, jun; D011905:Genes, ras; D019278:Matrix Metalloproteinase 3; D008666:Metalloendopeptidases / Q000235:genetics; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis / Q000235:genetics*; D009374:Neoplasms, Experimental / Q000209:etiology; D053495:Osteopontin; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D012795:Sialoglycoproteins / Q000235:genetics; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D012795:Sialoglycoproteins; C506896:Spp1 protein, mouse; C506897:Spp1 protein, rat; D018808:Transcription Factor AP-1; D053495:Osteopontin; D017364:Collagenases; D008666:Metalloendopeptidases; D019278:Matrix Metalloproteinase 3