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Updated: Mar 1, 2026
Bioluminescence Imaging of NADPH Oxidase Activity in Different Animal Models
Published on: October 22, 2012
Decoding NADPH oxidase 4 expression in human tumors
Jennifer L Meitzler1, Hala R Makhlouf2, Smitha Antony2
1Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
Abstract:
NADPH oxidase 4 (NOX4) is a redox active, membrane-associated protein that contributes to genomic instability, redox signaling, and radiation sensitivity in human cancers based on its capacity to generate H2O2 constitutively. Most studies of NOX4 in malignancy have focused on the evaluation of a small number of tumor cell lines and not on human tumor specimens themselves; furthermore, these studies have often employed immunological tools that have not been well characterized. To determine the prevalence of NOX4 expression across a broad range of solid tumors, we developed a novel monoclonal antibody that recognizes a specific extracellular region of the human NOX4 protein, and that does not cross-react with any of the other six members of the NOX gene family. Evaluation of 20 sets of epithelial tumors revealed, for the first time, high levels of NOX4 expression in carcinomas of the head and neck (15/19 patients), esophagus (12/18 patients), bladder (10/19 patients), ovary (6/17 patients), and prostate (7/19 patients), as well as malignant melanoma (7/15 patients) when these tumors were compared to histologically-uninvolved specimens from the same organs. Detection of NOX4 protein upregulation by low levels of TGF-β1 demonstrated the sensitivity of this new probe; and immunofluorescence experiments found that high levels of endogenous NOX4 expression in ovarian cancer cells were only demonstrable associated with perinuclear membranes. These studies suggest that NOX4 expression is upregulated, compared to normal tissues, in a well-defined, and specific group of human carcinomas, and that its expression is localized on intracellular membranes in a fashion that could modulate oxidative DNA damage.
Insights
NADPH oxidase 4 (NOX4) is upregulated in several human carcinomas, including head and neck, esophagus, and bladder cancers. This finding, using a novel antibody, suggests NOX4
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- NADPH oxidase 4 (NOX4) generates hydrogen peroxide, impacting genomic instability, redox signaling, and radiation sensitivity in cancers.
- Previous studies on NOX4 in malignancy primarily used limited cell lines and poorly characterized immunological tools, neglecting human tumor specimens.
Purpose of the Study:
- To investigate the prevalence of NOX4 expression across diverse solid tumors using a newly developed, specific monoclonal antibody.
- To characterize the expression patterns and localization of NOX4 in human tumor tissues.
Main Methods:
- Development of a novel monoclonal antibody targeting a specific extracellular region of human NOX4, ensuring no cross-reactivity with other NOX family members.
- Evaluation of NOX4 protein expression in 20 sets of epithelial tumors and malignant melanoma compared to adjacent normal tissues.
- Immunofluorescence to determine NOX4 localization within cancer cells.
Main Results:
- High NOX4 expression was identified in carcinomas of the head and neck (15/19), esophagus (12/18), bladder (10/19), ovary (6/17), and prostate (7/19), as well as malignant melanoma (7/15).
- NOX4 upregulation was detected in response to low levels of TGF-β1, confirming the antibody's sensitivity.
- Immunofluorescence revealed NOX4 localized to perinuclear membranes in ovarian cancer cells with high endogenous expression.
Conclusions:
- NOX4 is significantly upregulated in specific human carcinomas compared to normal tissues.
- The novel antibody provides a reliable tool for assessing NOX4 expression in human tumors.
- NOX4's intracellular membrane localization suggests a role in modulating oxidative DNA damage in cancer.
