Related Experiment Video
Updated: Aug 6, 2026

Focus Formation: A Cell-based Assay to Determine the Oncogenic Potential of a Gene
Published on: December 31, 2014
A direct link between expression of urokinase plasminogen activator receptor, growth rate and oncogenic
R Mazzieri1, F Furlan, S D'Alessio
1Department of Molecular Biology and Functional Genomics, Università Vita Salute San Raffaele, Milano, Italy.
Abstract:
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.
Related Concept Videos
Mitogens and the Cell Cycle
mTOR Signaling and Cancer Progression
The mTOR pathway or the...
PI3K/mTOR/AKT Signaling Pathway
The Ras Gene
Ras is a superfamily...

