title: Dual effect of the antianginal drug fendiline on bladder female transitional carcinoma cells: mobilization of intracellular CA2+ and induction of cell death.
abstract: The effect of fendiline, an antianginal drug, on cytosolic free Ca2+ levels ([Ca2+]i) in populations of bladder female transitional carcinoma (BFTC) cells was explored using fura-2 as a Ca2+ indicator. Fendiline at concentrations between 3 and 200 micromol/l increased [Ca2+]i in a concentration-dependent manner and the signal saturated at 100 micromol/l. The [Ca2+]i signal was biphasic, with an initial rise and a slow decay. Ca2+ removal inhibited the Ca2+ signal by about half in peak amplitude. Adding 3 mmol/l Ca2+ increased [Ca2+]i in cells pretreated with 100 micromol/l fendiline in Ca2+ -free medium, suggesting that fendiline induced Ca2+ influx via capacitative Ca2+ entry. In Ca2+ -free medium, pretreatment with 1 micromol/l thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor) to deplete the endoplasmic reticulum Ca2+ store inhibited most of the 100 micromol/l fendiline-induced internal Ca2+ release; and conversely, pretreatment with 100 micromol/l fendiline partly inhibited 1 micromol/l thapsigargin-induced Ca2+ release. This indicates that the major internal Ca2+ store of fendiline-induced [Ca2+]i increases is located in the endoplasmic reticulum. The Ca2+ release induced by 100 micromol/l fendiline may be partly mediated by inositol 1,4,5-trisphosphate, because the [Ca2+]i increase was inhibited by 50% by inhibiting phospholipase C with 2 micromol/l U73122. Fendiline (100 micromol/l) decreased cell viability by 12-44% after being added to cells for 2- 30 min. Together, the findings indicate that in BFTC cells, fendiline exerts a dual effect: mobilization of intracellular Ca2+ and induction of cell death.
authors.affiliation: Department of Medical Education, National Sun Yat-sen University, Kaohsiung, Taiwan.
authors.forename: C R
authors.initials: CR
authors.lastname: Jan
authors.forename: C C
authors.initials: CC
authors.lastname: Yu
authors.forename: J K
authors.initials: JK
authors.lastname: Huang
mesh_terms: D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002295:Carcinoma, Transitional Cell / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005275:Fendiline / Q000494:pharmacology*; D005456:Fluorescent Dyes; D016257:Fura-2; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*
chemical_list: D000889:Anti-Arrhythmia Agents; D005456:Fluorescent Dyes; D015544:Inositol 1,4,5-Trisphosphate; D005275:Fendiline; D002118:Calcium; D016257:Fura-2