title: Paclitaxel induces calcium oscillations via an inositol 1,4,5-trisphosphate receptor and neuronal calcium sensor 1-dependent mechanism.
abstract: Taxol (Paclitaxel) is an important natural product for the treatment of solid tumors. Despite a well documented tubulin-stabilizing effect, many side effects of taxol therapy cannot be explained by cytoskeletal mechanisms. In the present study submicromolar concentrations of taxol, mimicking concentrations found in patients, induced cytosolic calcium (Ca(2+)) oscillations in a human neuronal cell line. These oscillations were independent of extracellular and mitochondrial Ca(2+) but dependent on intact signaling via the phosphoinositide signaling pathway. We identified a taxol binding protein, neuronal Ca(2+) sensor 1 (NCS-1), a Ca(2+) binding protein that interacts with the inositol 1,4,5-trisphosphate receptor from a human brain cDNA phage display library. Taxol increased binding of NCS-1 to the inositol 1,4,5-trisphosphate receptor. Short hairpin RNA-mediated knockdown of NCS-1 in the same cell line abrogated the response to taxol but not to other agonists stimulating the phosphoinositide signaling pathway. These findings are important for studies involving taxol as a research tool in cell biology and may help to devise new strategies for the management of side effects induced by taxol therapy.
authors.affiliation: Department of Pharmacology, Yale University, New Haven, CT 06520, USA.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Boehmerle
authors.forename: Ute
authors.initials: U
authors.lastname: Splittgerber
authors.forename: Michael B
authors.initials: MB
authors.lastname: Lazarus
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: McKenzie
authors.forename: David G
authors.initials: DG
authors.lastname: Johnston
authors.forename: David J
authors.initials: DJ
authors.lastname: Austin
authors.forename: Barbara E
authors.initials: BE
authors.lastname: Ehrlich
mesh_terms: D001710:Biotin / Q000737:chemistry; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects*; D045744:Cell Line, Tumor; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism; D051580:Neuronal Calcium-Sensor Proteins / Q000235:genetics / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D017239:Paclitaxel / Q000737:chemistry / Q000494:pharmacology*; D034622:RNA Interference
chemical_list: D053496:Inositol 1,4,5-Trisphosphate Receptors; D051580:Neuronal Calcium-Sensor Proteins; D009479:Neuropeptides; C101464:frequenin calcium sensor proteins; D001710:Biotin; D017239:Paclitaxel; D002118:Calcium