Econazole-evoked [Ca2+]i rise and non-Ca2+-triggered cell death in rabbit corneal epithelial cells (SIRC).
The effects of econazole, an antifungal drug applied for treatment of keratitis and mycotic corneal ulcer, on cytosolic-free Ca(2+) concentrations ([Ca(2+)](i)) and viability of corneal cells was examined by using SIRC rabbit corneal epithelial cells as model. [Ca(2+)](i) and cell viability were measured by using the fluorescent dyes fura-2 and WST-1, respectively. Econazole at concentrations > or = 1 microM increased [Ca(2+)](i) in a concentration-dependent manner. The Ca(2+) signal was reduced partly by removing extracellular Ca(2+). The econazole-induced Ca(2+) influx was insensitive to L-type Ca(2+) channel blockers and protein kinase C modulators. In Ca(2+)-free medium, after pretreatment with 20 microM econazole, [Ca(2+)](i) rises induced by 1 microM thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor) were abolished. Conversely, thapsigargin pretreatment also abolished econazole-induced [Ca(2+)](i) rises. Inhibition of phospholipase C with 2 microM U73122 did not change econazole-induced [Ca(2+)](i) rises. At concentrations between 10 and 80 microM, econazole killed cells in a concentration-dependent manner. The cytotoxic effect of 20 microM econazole was not reversed by prechelating cytosolic Ca(2+) with BAPTA. This shows that in SIRC cells econazole induces [Ca(2+)](i) rises by causing Ca(2+) release from the endoplasmic reticulum and Ca(2+) influx from unknown pathways. Econazole-caused cytotoxicity was independent from a preceding [Ca(2+)](i) rise.
Chien
Jau-Min
JM
Department of Medicine, Ping Tung Christian Hospital, Ping Tung, Taiwan.
Huang
Chorng-Chih
CC
Cheng
He-Hsiung
HH
Lin
Ko-Long
KL
Chen
Wei-Chuan
WC
Tseng
Pi-Lai
PL
Chou
Chiang-Ting
CT
Tsai
Jeng-Yu
JY
Liao
Wei-Chuan
WC
Wang
Being-Whey
BW
Chang
Po-Min
PM
Jan
Chung-Ren
CR
D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects*; D016923:Cell Death; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003315:Cornea / Q000187:drug effects* / Q000378:metabolism; D004464:Econazole / Q000494:pharmacology*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011817:Rabbits; D019284:Thapsigargin / Q000494:pharmacology
D000935:Antifungal Agents; D002121:Calcium Channel Blockers; D004791:Enzyme Inhibitors; D019284:Thapsigargin; D004464:Econazole; D011493:Protein Kinase C; D002118:Calcium