TY - JOUR
T1 - Modulation of redox signaling promotes apoptosis in epithelial ovarian cancer cells
AU - Jiang, Zhongliang
AU - Fletcher, Nicole M.
AU - Ali-Fehmi, Rouba
AU - Diamond, Michael P.
AU - Abu-Soud, Husam M.
AU - Munkarah, Adnan R.
AU - Saed, Ghassan M.
PY - 2011/8
Y1 - 2011/8
N2 - Objective: Epithelial ovarian cancer (EOC) cells are known to be resistant to apoptosis through a mechanism that may involve alteration in their redox balance. NADPH oxidase is a major source of intracellular superoxide, which is converted to the less toxic product by superoxide dismutase (SOD). Superoxide contributes to hypoxia inducible factor (HIF)-1α stabilization. We sought to determine the effects of inhibiting the generation of intracellular reactive oxygen species (ROS) on apoptosis of EOC cells. Methods: Diphenyleneiodonium (DPI), an irreversible ROS inhibitor, was used to inhibit the generation of ROS in EOC cell lines, SKOV-3 and MDAH-2774, followed by assessment of apoptosis, NADPH oxidase, SOD3 and HIF-1α expression. A combination of immunohistochemistry, immunoprecipitation/western blot, and real-time RT-PCR were utilized to evaluate the expression of these enzymes in EOC cells as well as normal ovarian tissue and ovarian cancer tissue specimens. Results: DPI treatment significantly induced apoptosis in both EOC cell lines as evident by increased caspase-3 activity and TUNEL assay. Additionally, both EOC cell lines were found to express NADPH oxidase, HIF-1α, and SOD3, which were highly sensitive to DPI treatment. DPI treatment resulted in reduced NADPH oxidase, SOD3 and HIF-1α levels. Furthermore, ovarian cancer tissues were found to manifest higher NADPH oxidase levels as compared to normal ovarian tissues. Conclusions: These data suggest that lowering oxidative stress, possibly through the inhibition of NADPH oxidase, induces apoptosis in ovarian cancer cells and may serve as a potential target for cancer therapy.
AB - Objective: Epithelial ovarian cancer (EOC) cells are known to be resistant to apoptosis through a mechanism that may involve alteration in their redox balance. NADPH oxidase is a major source of intracellular superoxide, which is converted to the less toxic product by superoxide dismutase (SOD). Superoxide contributes to hypoxia inducible factor (HIF)-1α stabilization. We sought to determine the effects of inhibiting the generation of intracellular reactive oxygen species (ROS) on apoptosis of EOC cells. Methods: Diphenyleneiodonium (DPI), an irreversible ROS inhibitor, was used to inhibit the generation of ROS in EOC cell lines, SKOV-3 and MDAH-2774, followed by assessment of apoptosis, NADPH oxidase, SOD3 and HIF-1α expression. A combination of immunohistochemistry, immunoprecipitation/western blot, and real-time RT-PCR were utilized to evaluate the expression of these enzymes in EOC cells as well as normal ovarian tissue and ovarian cancer tissue specimens. Results: DPI treatment significantly induced apoptosis in both EOC cell lines as evident by increased caspase-3 activity and TUNEL assay. Additionally, both EOC cell lines were found to express NADPH oxidase, HIF-1α, and SOD3, which were highly sensitive to DPI treatment. DPI treatment resulted in reduced NADPH oxidase, SOD3 and HIF-1α levels. Furthermore, ovarian cancer tissues were found to manifest higher NADPH oxidase levels as compared to normal ovarian tissues. Conclusions: These data suggest that lowering oxidative stress, possibly through the inhibition of NADPH oxidase, induces apoptosis in ovarian cancer cells and may serve as a potential target for cancer therapy.
KW - Diphenyleneiodonium
KW - Epithelial ovarian cancer
KW - Hypoxia inducible factor-1 alpha
KW - NADPH oxidase
KW - Oxidative stress
KW - Superoxide dismutase
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U2 - 10.1016/j.ygyno.2011.04.051
DO - 10.1016/j.ygyno.2011.04.051
M3 - Article
C2 - 21620448
AN - SCOPUS:79960446246
SN - 0090-8258
VL - 122
SP - 418
EP - 423
JO - Gynecologic Oncology
JF - Gynecologic Oncology
IS - 2
ER -