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. 2000 Jan;20(1):139–148. doi: 10.1128/mcb.20.1.139-148.2000

FIG. 4.

FIG. 4

FTI-277 inhibits PI 3-kinase activity. (A and B) In vitro PI 3-kinase assay of the anti-p85 immunoprecipitates from OVCAR-3 and A2780 cells. Following serum starvation overnight, the cells were treated with or without FTI-277 for 12 h prior to IGF-1 (A) or 5% FCS (B) stimulation for 15 min. Basal levels of PI 3-kinase are not significantly different between OVCAR-3 and A2780 cells. However, IGF1- or serum-induced PI 3-kinase activity in both cell lines was inhibited by FTI-277. (C) Western blot analyses of immunoprecipitates from OVCAR-3 cells. Following FTI-277 treatment, the cells were lysed, immunoprecipitated with anti-p85 polyclonal antibody, and detected with an anti-p-Tyr antibody. The blots were reprobed with anti-p85 antibody. (D) FTI-277 does not directly inhibit serum-induced PI 3-kinase activation. An in vitro PI 3-kinase assay was carried out with immunoprecipitates from OVCAR-3 cells. After serum starvation and restimulation, FTI-277 (30 μM) was directly added to the kinase reaction (lane 3).