Inhibition of apoptosis in human retinal pigment epithelial cells treated with benzo(e)pyrene, a toxic component of cigarette smoke.
OBJECTIVE
To study the inhibitory effects of some agents or drugs (inhibitors) on benzo(e)pyrene (B(e)P)-induced cell death and apoptosis on human retinal pigment epithelial (ARPE-19) cells in vitro.


METHODS
ARPE-19 cells were pretreated with varying concentrations of different classes of inhibitors (calpain, benzyl isothiocyanate [BITC], simvastatin, epicatechin, genistein, resveratrol, and memantine) before B(e)P exposure. Cell viability (CV) was determined by a trypan blue dye-exclusion assay. Caspase-3/7 and caspase-9 activities were measured by fluorochrome assays. The production of reactive oxygen/nitrogen species (ROS/RNS) was measured with 2',7'-dicholorodihydrofluorescein diacetate dye assay.


RESULTS
At 30-microM concentrations, the genistein, resveratrol, and memantine inhibitors were able to reverse significantly the loss of cell viability, the activation of caspase-3/7 and caspase-9, and the production of ROS/RNS in ARPE-19 cell cultures. Memantine was the most potent and genistein was the least effective inhibitor in blocking the B(e)P-induced effects. Calpain, BITC, simvastatin, and epicatechin did not reverse the loss of cell viability in B(e)P-treated ARPE-19 cells. As a matter of fact, at the concentrations studied (15, 30, 45 microM), the BITC plus B(e)P-treated cultures showed significantly lower cell viability than the B(e)P-treated culture alone, suggesting BITC-related toxicity.


CONCLUSIONS
Genistein, resveratrol, and memantine can reverse the apoptosis and oxidant production generated by B(e)P, a toxic element of smoking. These inhibitors may be beneficial against retinal diseases associated with the loss of RPE cells.
Mansoor
Saffar
S
Department of Ophthalmology, School of Medicine, University of California, Irvine, CA 92868, USA.
Gupta
Navin
N
Patil
A Jayaprakash
AJ
Estrago-Franco
Maria Fernanda
MF
Ramirez
Claudio
C
Migon
Rafael
R
Sapkal
Ashish
A
Kuppermann
Baruch D
BD
Kenney
M Cristina
MC
D017209:Apoptosis / Q000187:drug effects*; D001580:Benzopyrenes / Q000633:toxicity*; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D019833:Genistein / Q000494:pharmacology*; D006801:Humans; D008559:Memantine / Q000494:pharmacology*; D026361:Reactive Nitrogen Species / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D000077185:Resveratrol; D055213:Retinal Pigment Epithelium / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D012907:Smoking; D013267:Stilbenes / Q000494:pharmacology*
D001580:Benzopyrenes; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D013267:Stilbenes; C026487:benzo(e)pyrene; D019833:Genistein; D053148:Caspase 3; D053179:Caspase 7; D053453:Caspase 9; D000077185:Resveratrol; D008559:Memantine