Şehri Çolak, Oytun Erbaş

Institute of Experimental Medicine, Gebze-Kocaeli, Türkiye

Keywords: Cancer, DUOX, free radicals, NADPH oxidase, NOX4, reactive oxygen species.


The oxygen (O2) molecule, which is essential for every individual, is utilized by cells for their energy requirements. Harmful molecules released during the utilization of O2 are referred to as free radicals. Free radicals are molecules with unpaired electrons in their outermost layers. Their tendency to attack surrounding molecules and strive for stability is the source of this behavior. To counter their instability, the body has developed antioxidant systems. These systems are obtained both within the body and through dietary intake. Excess free radicals and a deficiency in antioxidants lead to oxidative stress. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases are molecules with a significant impact on the production pathway of free radicals. There are seven known types of NADPH oxidases, including five NADPH oxidases (NOX) and two dual oxidases (DUOX) varieties. The first discovered type, NOX2, plays a pivotal role in facilitating the discovery of other NOX species. The other species are classified based on their similarity to NOX2. Although NOX4, which is one of these NOX types, bears resemblance to others, the diseases it leads to, particularly cancer, exhibit differences. Digestive cancers resulting from free radicals are suppressed through NOX4. Research and studies on NOX4 continue due to its unique structure. This review discusses various free radical species, the functions and types of NOX enzymes, and the diseases that occur as a result of accumulations.

Cite this article as: Çolak Ş, Erbaş O. NOX-4: A key player in protecting against cancer from free radicals. D J Tx Sci 2023;8(1-2):48-55. doi: 10.5606/dsufnjt.2023.16.

Author Contributions

All authors contributed equally to the article.

Data Sharing Statement:
The data that support the findings of this study are available from the corresponding author upon reasonable request.

Conflict of Interest

The authors declared no conflicts of interest with respect to the authorship and/ or publication of this article.

Financial Disclosure

The authors received no financial support for the research and/or authorship of this article.