title: Quantification of farnesylmethylcysteine in lysates of peripheral blood mononuclear cells using liquid chromatography coupled with electrospray tandem mass spectrometry: pharmacodynamic assay for farnesyl transferase inhibitors.
abstract: Biological effectiveness is an important parameter in determining optimal dosages of molecular targeted drugs, such as farnesyl transferase inhibitors. To determine concentration-effect relationships, robust and quantitative biological assays are a prerequisite. Here, we present a novel assay for protein farnesylation that is based on generation of the biomarker farnesylmethylcysteine (FmC). Quantification was performed with liquid chromatography coupled to tandem mass spectrometry. The assay has been validated based on the most recent FDA guidelines for bioanalytical validation, and all results were within requirements. FmC is formed under the action of an endogenous protease that is activated upon cell lysis. The biomarker could be detected in A549 human lung cancer cells as well as in human peripheral blood mononuclear cells. Incubation of A549 cells with AZD3409, a novel prenyl transferase inhibitor, resulted in a significant decrease of the FmC concentration in the lysates. These findings provide a very good starting point for use of this assay in preclinical and clinical dose finding studies with FTIs.
authors.affiliation: Department of Pharmacy & Pharmacology, Slotervaart Hospital/The Netherlands Cancer Institute, Louwesweg 6, 1066 EC Amsterdam, The Netherlands.
authors.forename: Natalie M G M
authors.initials: NM
authors.lastname: Appels
authors.forename: Hilde
authors.initials: H
authors.lastname: Rosing
authors.forename: Trevor C
authors.initials: TC
authors.lastname: Stephens
authors.forename: Jan H M
authors.initials: JH
authors.lastname: Schellens
authors.forename: Jos H
authors.initials: JH
authors.lastname: Beijnen
mesh_terms: D001681:Biological Assay / Q000379:methods*; D004791:Enzyme Inhibitors / Q000032:analysis* / Q000378:metabolism; D051231:Farnesyltranstransferase / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D004791:Enzyme Inhibitors; D051231:Farnesyltranstransferase