NOX5 NAD(P)H oxidase regulates growth and apoptosis in DU 145 prostate cancer cells.
Reactive oxygen species (ROS) appear to play an important role in regulating growth and survival of prostate cancer. However, the sources for ROS production in prostate cancer cells have not been determined. We report that ROS are generated by intact American Type Culture Collection DU 145 cells and by their membranes through a mechanism blocked by NAD(P)H oxidase inhibitors. ROS are critical for growth in these cells, because NAD(P)H oxidase inhibitors and antioxidants blocked proliferation. Components of the human phagocyte NAD(P)H oxidase, p22phox and gp91phox, as well as the Ca2+ concentration-responsive gp91phox homolog NOX5 were demonstrated in DU 145 cells by RT-PCR and sequencing. Although the protein product for p22phox was not detectable, both gp91phox and NOX5 were identified throughout the cell by immunostaining and confocal microscopy and NOX5 immunostaining was enhanced in a perinuclear location, corresponding to enhanced ROS production adjacent to the nuclear membrane imaged by 2',7'-dichlorofluorescin diacetate oxidation. The calcium ionophore ionomycin dramatically stimulated ferricytochrome c reduction in cell media, further supporting the importance of NOX5 for ROS production. Antisense oligonucleotides for NOX5 inhibited ROS production and cell proliferation in DU 145 cells. In contrast, antisense oligonucleotides to p22phox or gp91phox did not impair cell growth. Inhibition of ROS generation with antioxidants or NAD(P)H oxidase inhibitors increased apoptosis in cells. These results indicate that ROS generated by the newly described NOX5 oxidase are essential for prostate cancer growth, possibly by providing trophic intracellular oxidant tone that retards programmed cell death.
Brar
Sukhdev S
SS
Department of Internal Medicine, Carolinas Medical Center, Charlotte, NC 28232, USA.
Corbin
Zachary
Z
Kennedy
Thomas P
TP
Hemendinger
Richelle
R
Thornton
Lisa
L
Bommarius
Bettina
B
Arnold
Rebecca S
RS
Whorton
A Richard
AR
Sturrock
Anne B
AB
Huecksteadt
Thomas P
TP
Quinn
Mark T
MT
Krenitsky
Kevin
K
Ardie
Kristia G
KG
Lambeth
J David
JD
Hoidal
John R
JR
D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D002277:Carcinoma / Q000201:enzymology*; D002455:Cell Division / Q000187:drug effects / Q000235:genetics*; D002471:Cell Transformation, Neoplastic / Q000187:drug effects / Q000378:metabolism; D003574:Cytochrome c Group / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007476:Ionophores / Q000494:pharmacology; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000074662:NADPH Oxidase 2; D000074664:NADPH Oxidase 5; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009685:Nuclear Envelope / Q000378:metabolism; D020320:Oligoribonucleotides, Antisense / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D011471:Prostatic Neoplasms / Q000201:enzymology*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000975:Antioxidants; D003574:Cytochrome c Group; D004791:Enzyme Inhibitors; D007476:Ionophores; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D020320:Oligoribonucleotides, Antisense; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D000074664:NADPH Oxidase 5; D019255:NADPH Oxidases; C431571:NOX5 protein, human