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Updated: Jun 2, 2026

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
Published on: March 9, 2012
Inhibition of tumor promoter induced transformation by expression of the small GTP-binding protein Rac in JB6 cells
1US FDA,HEPATATIS LAB,DTTD,BETHESDA,MD 20892. NCI,FREDERICK CANC RES & DEV CTR,GENE REGULAT SECT,LAB BIOCHEM PHYSIOL,FREDERICK,MD 21702.
Abstract:
The small GTP-binding protein rac-1 has been reported to be a mediator for tumor promoter, growth factor and serum-induced cell membrane ruffling. We have stably overexpressed rac-1 in JB6 P+ cells. In contrast to rac-1 expressing NIH/3T3 cells, all JB6 transfectants expressing rac-1 did not show tumorigenic transformation (forward progression) but instead showed anti-oncogenic effects (backward progression). Transfectants expressing high levels of rac-1 were blocked for TPA-, EGF- and serum-induced transformation, while transfectants expressing lower levels of rac-1 were completely blocked for EGF- and serum-induced transformation but only partially inhibited for TPA-induced transformation compared with vector control transfectants.
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