NADPH oxidase 5 (NOX5)—induced reactive oxygen signaling modulates normoxic HIF‐1α and p27^Kip1 expression in malignant melanoma and other human tumors

Abstract

NADPH oxidase 5 (NOX5) generated reactive oxygen species (ROS) have been implicated in signaling cascades that regulate cancer cell proliferation. To evaluate and validate NOX5 expression in human tumors, we screened a broad range of tissue microarrays (TMAs), and report substantial overexpression of NOX5 in malignant melanoma and cancers of the prostate, breast, and ovary. In human UACC-257 melanoma cells that possesses high levels of functional endogenous NOX5, overexpression of NOX5 resulted in enhanced cell growth, increased numbers of BrdU positive cells, and increased γ-H2AX levels. Additionally, NOX5-overexpressing (stable and inducible) UACC-257 cells demonstrated increased normoxic HIF-1α expression and decreased p27Kip1 expression. Similarly, increased normoxic HIF-1α expression and decreased p27Kip1 expression were observed in stable NOX5-overexpressing clones of KARPAS 299 human lymphoma cells and in the human prostate cancer cell line, PC-3. Conversely, knockdown of endogenous NOX5 in UACC-257 cells resulted in decreased cell growth, decreased HIF-1α expression, and increased p27Kip1 expression. Likewise, in an additional human melanoma cell line, WM852, and in PC-3 cells, transient knockdown of endogenous NOX5 resulted in increased p27Kip1 and decreased HIF-1α expression. Knockdown of endogenous NOX5 in UACC-257 cells resulted in decreased Akt and GSK3β phosphorylation, signaling pathways known to modulate p27Kip1 levels. In summary, our findings suggest that NOX5 expression in human UACC-257 melanoma cells could contribute to cell proliferation due, in part, to the generation of high local concentrations of extracellular ROS that modulate multiple pathways that regulate HIF-1α and networks that signal through Akt/GSK3β/p27Kip1.

Periprostatic Adipose Tissue Favors Prostate Cancer Cell Invasion in an Obesity-Dependent Manner: Role of Oxidative Stress

“…HIF1 also responds to nonhypoxic stimuli, including ROS, which regulate HIF1a stability and transcriptional activity (42). A very recent report demonstrates that HIF1a expression is upregulated in prostate cancer cells with induced NOX5 overexpression (43).…”

NOX5: Molecular biology and pathophysiology

“…Overexpression of Noxs and uncontrolled redox‐dependent cell proliferation have been demonstrated in various cancers (Gào & Schöttker, ; Roy et al., ). NOX5 expression and activity are increased in gastric cancer, malignant melanoma, breast cancer, prostate cancer and oesophageal cancer (Antony et al., ; Dho et al., ; Gào & Schöttker, ; Kalatskaya, ; Roy et al., ). Increased Nox activity and dysregulated production of ROS cause tissue injury, DNA damage and uncontrolled cell proliferation that are already evident in pre‐malignant conditions, especially Barrett's oesophagitis (Kalatskaya, ).…”

“…Increased Nox activity and dysregulated production of ROS cause tissue injury, DNA damage and uncontrolled cell proliferation that are already evident in pre‐malignant conditions, especially Barrett's oesophagitis (Kalatskaya, ). Pathways implicated in these NOX5–ROS‐dependent processes include signalling molecules (MAP kinases, PI3K, PKC and p27Kip1), transcription factors (APE1/Ref‐1, hypoxia‐inducible factor‐1α, AP‐1, Nrf2, nuclear factor‐κB, p53, FOXO, STAT5A and β‐catenin) (Antony et al., ; Dho et al., ; Roy et al., ) and adaptor proteins (Ruk/CIN 85) (Bazalii, Horak, Pasi chn yk, Komisarenko, & Drobot, ).…”

Gene expression and prognosis of NOX family members in gastric cancer

“…NOX5-derived ROS is suggested to promote proliferation of prostate cancer cell by modulating the activity and expression of protein kinase C zeta and c-Jun N-terminal kinase, 9 and enhance cell growth of melanoma through activation of hypoxia-inducible factor 1-alpha signaling pathways. 42 But, so far, little is known about the function of NOX5 in GC. In the present study, we found NOX5 mRNA expression was modestly lower in GC tissues compared with that in normal stomach tissues.…”