title: Photochemical modulation of Ras-mediated signal transduction using caged farnesyltransferase inhibitors: activation by one- and two-photon excitation.
abstract: The creation of caged molecules involves the attachment of protecting groups to biologically active compounds such as ligands, substrates and drugs that can be removed under specific conditions. Photoremovable caging groups are the most common due to their ability to be removed with high spatial and temporal resolution. Here, the synthesis and photochemistry of a caged inhibitor of protein farnesyltransferase is described. The inhibitor, FTI, was caged by alkylation of a critical thiol group with a bromohydroxycoumarin (Bhc) moiety. While Bhc is well established as a protecting group for carboxylates and phosphates, it has not been extensively used to cage sulfhydryl groups. The resulting caged molecule, Bhc-FTI, can be photolyzed with UV light to release the inhibitor that prevents Ras farnesylation, Ras membrane localization and downstream signaling. Finally, it is shown that Bhc-FTI can be uncaged by two-photon excitation to produce FTI at levels sufficient to inhibit Ras localization and alter cell morphology. Given the widespread involvement of Ras proteins in signal transduction pathways, this caged inhibitor should be useful in a plethora of studies.
authors.affiliation: Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Abate-Pella
authors.forename: Nicholette A
authors.initials: NA
authors.lastname: Zeliadt
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Ochocki
authors.forename: Janel K
authors.initials: JK
authors.lastname: Warmka
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Dore
authors.forename: David A
authors.initials: DA
authors.lastname: Blank
authors.forename: Elizabeth V
authors.initials: EV
authors.lastname: Wattenberg
authors.forename: Mark D
authors.initials: MD
authors.lastname: Distefano
mesh_terms: D000818:Animals; D002460:Cell Line; D003374:Coumarins / Q000737:chemistry; D004285:Dogs; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D051231:Farnesyltranstransferase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D055668:Photochemical Processes; D017785:Photons; D015398:Signal Transduction / Q000187:drug effects / Q000528:radiation effects; D013050:Spectrometry, Fluorescence; D018631:ras Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D003374:Coumarins; D004791:Enzyme Inhibitors; D051231:Farnesyltranstransferase; D018631:ras Proteins