A direct link between expression of urokinase plasminogen activator receptor, growth rate and oncogenic transformation in mouse embryonic fibroblasts.
In addition to its role in invasion and metastasis of several tumors, the multifunctional urokinase receptor uPAR (urokinase plasminogen activator receptor) is directly involved in the growth of several cancer cells in vitro and in vivo. We have compared growth rate and oncogenic transformation in wild-type (wt) or uPAR-/- mouse embryonic fibroblasts (MEFs). Surprisingly, uPAR-/- MEFs grew faster than wt MEFs. This agreed with elevated levels of cell cycle mediators like extracellular signal-regulated protein kinase, p38, AP1 and Cyclin D1. Infection with a uPAR retrovirus reverted the effect, decreasing the growth rate. When MEFs were transformed with H-Ras(V12) and E1A oncogenes, the efficiency of transformation in uPAR-/- MEFs was higher than in wt. UPAR-/- MEFs grew faster at low serum, produced more colonies in agar and produced tumors in vivo in nude mice with a lower latency period. The properties of the heterozygous uPAR+/- MEFs were always intermediate. We conclude therefore that in MEFs uPAR concentration controls cell proliferation and the transforming activity of some oncogenes.
Mazzieri
R
R
Department of Molecular Biology and Functional Genomics, Università Vita Salute San Raffaele, Milano, Italy.
Furlan
F
F
D'Alessio
S
S
Zonari
E
E
Talotta
F
F
Verde
P
P
Blasi
F
F
D000818:Animals; D017209:Apoptosis; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000502:physiology; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation; D006720:Homozygote; D051379:Mice; D018345:Mice, Knockout; D008819:Mice, Nude; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009361:Neoplasm Invasiveness; D015689:Oncogene Protein p21(ras) / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014161:Transduction, Genetic; D014162:Transfection; D019096:Vitronectin / Q000378:metabolism
C417743:Cdkn2a protein, mouse; D019941:Cyclin-Dependent Kinase Inhibitor p16; C524899:Plaur protein, mouse; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D018808:Transcription Factor AP-1; D019096:Vitronectin; D020928:Mitogen-Activated Protein Kinases; D015689:Oncogene Protein p21(ras)