Transformation and amplification of the K-fgf proto-oncogene in NIH-3T3 cells, and induction of metastatic potential.
A plasmid containing the K-fgf proto-oncogene linked to the dihydrofolate reductase gene has been constructed, and used in transfection experiments to investigate the effects of K-fgf expression on the tumorigenic and metastatic properties of NIH-3T3 fibroblasts. Analysis of cells transfected with K-fgf revealed that expression of the K-fgf proto-oncogene can, in a single step, induce both tumorigenic and metastatic characteristics, as determined in soft agar cloning experiments, and in tumorigenicity and experimental lung metastasis assays with BALB/c nu/nu mice. Selection for resistance to increasing concentrations of methotrexate lead to the isolation of a series of cell lines containing amplifications of both the dihydrofolate reductase gene and the linked K-fgf gene, which synthesized elevated levels of growth factor message and protein. The most highly resistant and gene amplified cell lines exhibited lower than expected levels of K-fgf mRNA, and also appeared to have down-regulated cell surface growth factor receptors. Further support for the concept that altered K-fgf expression can induce fully malignant and metastatic cells was obtained in experimental metastasis assays, where K-fgf transfected and gene amplified cell lines were highly aggressive.
Damen
J E
JE
Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Canada.
Greenberg
A H
AH
Wright
J A
JA
D000818:Animals; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D004351:Drug Resistance / Q000235:genetics; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D051519:Fibroblast Growth Factor 4; D005346:Fibroblast Growth Factors; D005784:Gene Amplification / Q000235:genetics*; D006133:Growth Substances / Q000235:genetics*; D006801:Humans; D008727:Methotrexate / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009362:Neoplasm Metastasis / Q000235:genetics*; D010957:Plasmids / Q000235:genetics; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D011519:Proto-Oncogenes / Q000235:genetics*; D011869:Radioligand Assay; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured; D014410:Tumor Stem Cell Assay
C496445:FGF4 protein, human; C496446:Fgf4 protein, mouse; D051519:Fibroblast Growth Factor 4; D006133:Growth Substances; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D016222:Fibroblast Growth Factor 2; D005346:Fibroblast Growth Factors; D013762:Tetrahydrofolate Dehydrogenase; D008727:Methotrexate