The Analysis of NADPH Quinone Reductase 1 (NQO1) Polymorphism in Polish Patients with Colorectal Cancer

Human NQO1 as a Selective Target for Anticancer Therapeutics and Tumor Imaging

Human NAD(P)H-quinone oxidoreductase1 (HNQO1) is a two-electron reductase antioxidant enzyme whose expression is driven by the NRF2 transcription factor highly active in the prooxidant milieu found in human malignancies. The resulting abundance of NQO1 expression (up to 200-fold) in cancers and a barely detectable expression in body tissues makes it a selective marker of neoplasms. NQO1 can catalyze the repeated futile redox cycling of certain natural and synthetic quinones to their hydroxyquinones, consuming NADPH and generating rapid bursts of cytotoxic reactive oxygen species (ROS) and H2O2. A greater level of this quinone bioactivation due to elevated NQO1 content has been recognized as a tumor-specific therapeutic strategy, which, however, has not been clinically exploited. We review here the natural and new quinones activated by NQO1, the catalytic inhibitors, and the ensuing cell death mechanisms. Further, the cancer-selective expression of NQO1 has opened excellent opportunities for distinguishing cancer cells/tissues from their normal counterparts. Given this diagnostic, prognostic, and therapeutic importance, we and others have engineered a large number of specific NQO1 turn-on small molecule probes that remain latent but release intense fluorescence groups at near-infrared and other wavelengths, following enzymatic cleavage in cancer cells and tumor masses. This sensitive visualization/quantitation and powerful imaging technology based on NQO1 expression offers promise for guided cancer surgery, and the reagents suggest a theranostic potential for NQO1-targeted chemotherapy.

Role of NADPH Quinone Reductase 1 (NQO1) Polymorphism in Prevention, Diagnosis, and Treatment of Gastrointestinal Cancers

Most cancer deaths are related to gastrointestinal (GI) cancers. Several environmental and genetic factors are effective in the occurrence of GI cancers, such as esophageal, stomach, colorectal, liver, and pancreatic cancers. In addition to risk factors related to lifestyle, reactive oxygen species (ROS) also play a role in GI cancers, and an increase in the amount of free radicals can lead to oxidative stress and increase the probability of malignancies. NQO1 is part of the body's antioxidant defense system that protects cells against mutagenesis and carcinogenesis. NQO1 is responsible for reducing quinones to hydroquinone and preventing the generation of ROS by catalyzing the reaction. The existence of single nucleotide polymorphisms (SNPs) of NADPH Quinone Reductase 1 (NQO1), such as 609C>T NQO1, leads to a decrease in NQO1 enzyme activity. Some NQO1 polymorphisms may increase the risk of gastrointestinal cancer. So, the C609T polymorphism in the NQO1 gene has been found to be effective in causing gastrointestinal cancers. On the other hand, it is very important to know the role of biomarkers in the prognosis and management of cancer treatment. Therefore, this study investigated the role of NQO1 as a biomarker in the management of gastrointestinal cancers (prevention, diagnosis and treatment).

Review on NAD(P)H dehydrogenase quinone 1 (NQO1) pathway

NQO1 is an enzyme present in humans which is encoded by NQO1 gene. It is a protective antioxidant agent, versatile cytoprotective agent and regulates the oxidative stresses of chromatin binding proteins for DNA damage in cancer cells. The oxidization of cellular pyridine nucleotides causes structural alterations to NQO1 and changes in its capacity to binding of proteins. A strategy based on NQO1 to have protective effect against cancer was developed by organic components to enhance NQO1 expression. The quinone derivative compounds like mitomycin C, RH1, E09 (Apaziquone) and β-lapachone causes cell death by NQO1 reduction of two electrons. It was also known to be overexpressed in various tumor cells of breast, lung, cervix, pancreas and colon when it was compared with normal cells in humans. The mechanism of NQO1 by the reduction of FAD by NADPH to form FADH2 is by two ways to inhibit cancer cell development such as suppression of carcinogenic metabolic activation and prevention of carcinogen formation. The NQO1 exhibit suppression of chemical-mediated carcinogenesis by various properties of NQO1 which includes, detoxification of quinone scavenger of superoxide anion radical, antioxidant enzyme, protein stabilizer. This review outlines the NQO1 structure, mechanism of action to inhibit the cancer cell, functions of NQO1 against oxidative stress, drugs acting on NQO1 pathways, clinical significance.