In vitro activity: FTI-277 inhibits Ras processing with an IC50 of 100 nM, but not the geranylgeranylated Rap1A processing in whole cells. FTI-277 induces accumulation of cytoplasmic non-farnesylated H-Ras, accumulates inactive Ras/Raf complexes in the cytoplasm, and blocks constitutive MAPK activation in H-RasF cells. FTI-277 causes increased apoptosis after irradiation and increases radiosensitivity in H-ras-transformed rat embryo cells. FTI-277 also inhibits cell growth and induces apoptosis in drug-resistant myeloma tumor cells. In SH-SY5Y cells, FTI-277 diminishes the toxic effects of methamphetamine on induction in cell degeneration, activation in c-Jun-N-terminal kinase cascades, and Ras activation.

Kinase Assay: FTase and GGTase I activities from 60,000×g supernatants of human Burkitt lymphoma (Daudi) cells are assayed. Inhibition studies are performed by determining the ability of Ras CAAX peptidomimetics to inhibit the transfer of [3H]farnesyl and [3H]geranylgeranyl from [3H]farnesylpyrophosphate and [3H]geranylgeranylpyrophosphate to H-Ras-CVLS and H-Ras-CVLL, respectively.

Cell Assay: Cells (8226, U266, and H929 multiple myeloma cell lines) are seeded at 8000–14 000 cells/well in 96-well plates. To establish a dose–response to FTI-277, cells are incubated for 96 h in two-fold serial dilutions ranging from 3.75 times 10-7 M to 1 times 10-5 M. Following continuous drug exposure, 50 μL MTT dye is added. The insoluble formazan complex is solubilized with DMSO and absorbance measured at 540 nm. IC50s and 95% confidence intervals are calculated by regression analysis of the linear portion of the dose–response curve.

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