Significance of NQO1 overexpression for prognostic evaluation of gastric adenocarcinoma

Switching on Supramolecular DNA Junction Binding Using a Human Enzyme

Non-canonical DNA junction structures are important in human disease and in nucleic acid nanoscience and there is a growing interest in how to bind and modulate them. A key next step is to exert "on command" control over such binding. Herein we develop a new metallo-supramolecular triple-helicate cylinder agent that is inert to DNA junction binding until activated by human enzyme NAD(P)H:quinone oxidoreductase 1 (NQO1) and its cofactor nicotinamide adenine dinucleotide phosphate (NADPH). This inactive cylinder bears six flexible arms each with a quinone group at the termini. Reduction by the enzyme leads to all six arms being removed, transforming the inert cylinder into a new and active metallo-supramolecular agent that binds junctions. This gives the ability to "switch-on" DNA junction formation and binding in response to the presence of two external stimuli - a human enzyme overexpressed in many disease states, and NADPH - and absence of inhibitor, giving NAND logic control. Modelling indicates the binding activation originates not in steric unblocking but changes in conformational flexibility. The work provides the foundation for and a route map toward future designs of sophisticated, inert, and supramolecular structures which are transformed by enzymes into new, active, and supramolecular structures for a variety of potential applications.

Targeted delivery of napabucasin with radiotherapy improves outcomes in diffuse midline glioma

BACKGROUND

Diffuse midline glioma (DMG) is the most aggressive primary brain tumor in children. All previous studies examining the role of systemic agents have failed to demonstrate a survival benefit; the only standard of care is radiation therapy (RT). Successful implementation of radiosensitization strategies in DMG remains an essential and promising avenue of investigation. We explore the use of Napabucasin, an NAD(P)H quinone dehydrogenase 1 (NQO1)-bioactivatable reactive oxygen species (ROS)-inducer, as a potential therapeutic radiosensitizer in DMG.

METHODS

In this study, we conduct in vitro and in vivo assays using patient-derived DMG cultures to elucidate the mechanism of action of Napabucasin and its radiosensitizing properties. As penetration of systemic therapy through the blood-brain barrier (BBB) is a significant limitation to the success of DMG therapies, we explore focused ultrasound (FUS) and convection-enhanced delivery (CED) to overcome the BBB and maximize therapeutic efficacy.

RESULTS

Napabucasin is a potent ROS-inducer and radiosensitizer in DMG, and treatment-mediated ROS production and cytotoxicity are dependent on NQO1. In subcutaneous xenograft models, combination therapy with RT improves local control. After optimizing targeted drug delivery using CED in an orthotopic mouse model, we establish the novel feasibility and survival benefit of CED of Napabucasin concurrent with RT.

CONCLUSIONS

As nearly all DMG patients will receive RT as part of their treatment course, our validation of the efficacy of radiosensitizing therapy using CED to prolong survival in DMG opens the door for exciting novel studies of alternative radiosensitization strategies in this devastating disease while overcoming limitations of the BBB.

Simultaneous Targeting of NQO1 and SOD1 Eradicates Breast Cancer Stem Cells via Mitochondrial Futile Redox Cycling

Triple-negative breast cancer (TNBC) contains the highest proportion of cancer stem-like cells (CSC), which display intrinsic resistance to currently available cancer therapies. This therapeutic resistance is partially mediated by an antioxidant defense coordinated by the transcription factor NRF2 and its downstream targets that include NAD(P)H quinone oxidoreductase 1 (NQO1). In this study, we identified the antioxidant enzymes NQO1 and superoxide dismutase 1 (SOD1) as therapeutic vulnerabilities of ALDH+ epithelial-like CSCs and CD24-/loCD44+/hi mesenchymal-like CSCs in TNBC. Effective targeting of these CSC states was achieved by using isobutyl-deoxynyboquinone (IB-DNQ), a potent and specific NQO1-bioactivatable futile redox cycling molecule, which generated large amounts of reactive oxygen species including superoxide and hydrogen peroxide. Furthermore, the CSC killing effect was specifically enhanced by genetic or pharmacologic inhibition of SOD1, a copper-containing superoxide dismutase highly expressed in TNBC. Mechanistically, a significant portion of NQO1 resides in the mitochondrial intermembrane space, catalyzing futile redox cycling from IB-DNQ to generate high levels of mitochondrial superoxide, and SOD1 inhibition markedly potentiated this effect, resulting in mitochondrial oxidative injury, cytochrome c release, and activation of the caspase-3-mediated apoptotic pathway. Treatment with IB-DNQ alone or together with SOD1 inhibition effectively suppressed tumor growth, metastasis, and tumor-initiating potential in xenograft models of TNBC expressing different levels of NQO1. This futile oxidant-generating strategy, which targets CSCs across the epithelial-mesenchymal continuum, could be a promising therapeutic approach for treating patients with TNBC. Significance: Combining NQO1-bioactivatable futile oxidant generators with SOD1 inhibition eliminates breast cancer stem cells, providing a therapeutic strategy that may have wide applicability, as NQO1 and SOD1 are overexpressed in several cancers.

DPP9 regulates NQO1 and ROS to promote resistance to chemotherapy in liver cancer cells

Chemotherapy has been the standard treatment for liver cancer. However, intrinsic or acquired drug resistance remains a major barrier to successful treatment. At present, the underlying molecular mechanisms of chemoresistance in liver cancer have not been elucidated. Dipeptidyl peptidase 9 (DPP9) is a member of the dipeptidyl peptidase IV family that has been found to be highly expressed in a variety of tumors, including liver cancer. It is unclear whether DPP9 affects chemoresistance in liver cancer. In this study, we find that DPP9 weakens the responses of liver cancer cells to chemotherapy drugs by up-regulating NQO1 and inhibiting intracellular ROS levels. In terms of mechanism, DPP9 inhibits ubiquitin-mediated degradation of NRF2 protein by binding to KEAP1, up-regulates NRF2 protein levels, promotes mRNA transcription of NQO1, and inhibits intracellular ROS levels. In addition, the NQO1 inhibitor dicoumarol can enhance the efficacy of chemotherapy drugs in liver cancer cells. Collectively, our findings suggest that inhibiting DPP9/NQO1 signaling can serve as a potential therapeutic strategy for liver cancer.

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).

Pan-cancer and single-cell analysis reveal the prognostic value and immune response of NQO1

Background: Overexpression of the NAD(P)H: Quinone Oxidoreductase 1 (NQOI) gene has been linked with tumor progression, aggressiveness, drug resistance, and poor patient prognosis. Most research has described the biological function of the NQO1 in certain types and limited samples, but a comprehensive understanding of the NQO1's function and clinical importance at the pan-cancer level is scarce. More research is needed to understand the role of NQO1 in tumor infiltration, and immune checkpoint inhibitors in various cancers are needed. Methods: The NQO1 expression data for 33 types of pan-cancer and their association with the prognosis, pathologic stage, gender, immune cell infiltration, the tumor mutation burden, microsatellite instability, immune checkpoints, enrichment pathways, and the half-maximal inhibitory concentration (IC50) were downloaded from public databases. Results: Our findings indicate that the NQO1 gene was significantly upregulated in most cancer types. The Cox regression analysis showed that overexpression of the NQO1 gene was related to poor OS in Glioma, uveal melanoma, head and neck squamous cell carcinoma, kidney renal papillary cell carcinoma, and adrenocortical carcinoma. NQO1 mRNA expression positively correlated with infiltrating immune cells and checkpoint molecule levels. The single-cell analysis revealed a potential relationship between the NQO1 mRNA expression levels and the infiltration of immune cells and stromal cells in bladder urothelial carcinoma, invasive breast carcinoma, and colorectal cancer. Conversely, a negative association was noted between various drugs (17-AAG, Lapatinib, Trametinib, PD-0325901) and the NQO1 mRNA expression levels. Conclusion: NQO1 expression was significantly associated with prognosis, immune infiltrates, and drug resistance in multiple cancer types. The inhibition of the NQO1-dependent signaling pathways may provide a promising strategy for developing new cancer-targeted therapies.

Novel NQO1 substrates bearing two nitrogen redox centers: Design, synthesis, molecular dynamics simulations, and antitumor evaluation

By analyzing the crystal structure of NQO1, an additional binding region for the ligand was discovered. In this study, a series of derivatives with a novel skeleton bearing two nitrogen redox centers were designed by introducing amines or hydrazines to fit with the novel binding region of NQO1. Compound 24 with a (4-fluorophenyl)hydrazine substituent was identified as the most efficient substrate for NQO1 with the reduction rate and catalytic efficiency of 1972 ± 82 μmol NADPH/min/μmol NQO1 and 6.4 ± 0.4 × 10⁶ M^-1s^-1, respectively. Molecular dynamics (MD) simulation revealed that the distances between the nitrogen atom of the redox centers and the key Tyr128 and Tyr126 residues were 3.5 Å (N₁-Tyr128) and 3.4 Å (N₂-Tyr126), respectively. Compound 24 (IC₅₀/A549 = 0.69 ± 0.09 μM) showed potent antitumor activity against A549 cells both in vitro and in vivo through ROS generation via NQO1-mediated redox cycling, leading to a promising NQO1-targeting antitumor candidate.

Nrf2 antioxidant pathway and apoptosis induction and inhibition of NF-κB-mediated inflammatory response in human prostate cancer PC3 cells by Brassica oleracea var. acephala: An in vitro study

BACKGROUND

Brassica oleracea var. acephala is a good source of health-promoting biologically active compounds like phenolics, vitamins, and glucosinolates.

METHODS AND RESULTS

This in vitro research was conducted to evaluate the apoptotic, antioxidant, anti-inflammatory, and antiproliferative properties of ethanolic extract of Brassica oleracea var. acephala (EEBO) in PC3 prostate cancer cells. The LC-MS/MS technique was applied to identify the biomolecules of EEBO. The MTT assay was used to evaluate the cytotoxic effects of EEBO on PC3 cells. Moreover, qRT-PCR was used to examine the expression levels of Nrf2, NQO1, HO-1, NF-κB, TNF-α, IL-6, BAX, and BCL-2 in PC3 cell line. MMP was predicted by Rhodamine 123 staining, and release of cytochrome c was detected by an ELISA kit. Further, apoptosis was quantified by DNA fragmentation assay. The Western blotting method was used to detect the protein expression levels, and The DPPH assay was applied to determine the antioxidant effect of EEBO. The formula and structure of 19 biomolecules were predicted by LC-MS/MS. EEBO exhibited scavenging activity for DPPH. The MTT test showed EEBO reduced the viability of PC3 cells. The mRNA and protein levels of NRF2 pathway genes and BAX were increased, but those of the NF-κB pathway genes and BCL-2 were decreased in the EEBO-treated cells. Moreover, EEBO led to the diminution of MMP and enhanced the release of cytochrome c and DNA fragmentation, which resulted in apoptosis.

CONCLUSIONS

Molecular changes due to the anticancer impact of EEBO on PC3 were involved in the induction of Nrf2 antioxidant pathway and apoptosis and inhibition of inflammation.

High-throughput screening and genome-wide analyses of 44 anticancer drugs in the 1000 Genomes cell lines reveals an association of the NQO1 gene with the response of multiple anticancer drugs

Cancer patients exhibit a broad range of inter-individual variability in response and toxicity to widely used anticancer drugs, and genetic variation is a major contributor to this variability. To identify new genes that influence the response of 44 FDA-approved anticancer drug treatments widely used to treat various types of cancer, we conducted high-throughput screening and genome-wide association mapping using 680 lymphoblastoid cell lines from the 1000 Genomes Project. The drug treatments considered in this study represent nine drug classes widely used in the treatment of cancer in addition to the paclitaxel + epirubicin combination therapy commonly used for breast cancer patients. Our genome-wide association study (GWAS) found several significant and suggestive associations. We prioritized consistent associations for functional follow-up using gene-expression analyses. The NAD(P)H quinone dehydrogenase 1 (NQO1) gene was found to be associated with the dose-response of arsenic trioxide, erlotinib, trametinib, and a combination treatment of paclitaxel + epirubicin. NQO1 has previously been shown as a biomarker of epirubicin response, but our results reveal novel associations with these additional treatments. Baseline gene expression of NQO1 was positively correlated with response for 43 of the 44 treatments surveyed. By interrogating the functional mechanisms of this association, the results demonstrate differences in both baseline and drug-exposed induction.

In the burgeoning field of personalized medicine, genetic variation is recognized as a major contributor to patients’ differential responses to drugs. Lymphoblastoid cell lines (LCLs) are a consistent and convenient representation of cells used for in vitro research. Human genome sequencing with LCLs can identify new genes that influence individuals’ drug responses, including the dose-response relationship, which describes the relationship between physiological response and the amount of exposure to a substance. In this work, we conduct high-throughput screening and genome-wide association mapping using 680 LCLs from the 1000 Genomes Project to identify new genes that influence individual response to 44 widely used anticancer drugs. We found the NQO1 gene to be associated with the dose-response of several drugs, namely arsenic trioxide, erlotinib, trametinib, and the paclitaxel + epirubicin combination, and performed follow-up analyses to better understand its functional role in drug response. Our results indicate NQO1 expression is correlated with increased drug resistance and provide some evidence that SNP rs1800566 influences drug response by altering protein activity for these four treatments. With further research, NQO1 has potential use as a therapeutic target, for example, suppressing NQO1 expression to increase sensitivity to particular drugs.

Rational designed highly sensitive NQO1-activated near-infrared fluorescent probe combined with NQO1 substrates in vivo: An innovative strategy for NQO1-overexpressing cancer theranostics

Since NQO1 is overexpressed in many cancer cells, it can be used as a biomarker for cancer diagnosis and targeted therapy. NQO1 substrates show potent anticancer activity through the redox cycle mediated by NQO1, while the NQO1 probes can monitor NQO1 levels in cancers. High sensitivity of probes is needed for diagnostic imaging in clinic. In this study, based on the analysis of NQO1 catalytic pocket, the naphthoquinone trigger group 13 rationally designed by expanding the aromatic plane of the benzoquinone trigger group 10 shows significantly increased sensitivity to NQO1. The sensitivity of the naphthoquinone trigger group-based probe A was eight times higher than that of benzoquinone trigger group-based probe B in vivo. Probe A was selectively and efficiently sensitive to NQO1 with good safety profile and plasma stability, enabling its combination with NQO1 substrates in vivo for NQO1-overexpressing cancer theranostics for the first time.

Association of NQO1Pro187Ser polymorphism with clinical outcomes and survival of lung cancer patients treated with platinum chemotherapy

Background: The study was carried out to evaluate the association of NQO1 P187S polymorphism in North Indian lung cancer (LC) patients. We determined the effect of this polymorphic variant on the survival of LC patients. Patients & methods/results: This case-control study comprised a total of 1100 subjects. The genotyping was carried out using PCR-RFLP and statistical analysis was carried out. The variant TT genotype exhibited 3.5-fold higher odds in subjects with stage III (p = 0.0006), fivefold higher odds of lymph-node invasion (p = 0.007) and an odd of <1 in case of metastasis (p = 0.0028). Patients possessing TT genotype and administered with paclitaxel, exhibited a poor survival (3.57 vs 12.20 months; hazard ratio = 7.95; p = 0.0098). Conclusion: These results suggest that NQO1 variant genotype was not found to modulate risk toward LC. However, the variant genotype was found to be strongly correlated with stage III LC, lymph node invasion and was found to be positively correlating with metastasis.

Quinone oxidoreductase 1 is overexpressed in gastric cancer and associated with outcome of adjuvant chemotherapy and survival

BACKGROUND

Quinine oxidoreductase 1 (NQO1) plays a vital role in protecting normal cells against oxidative damage and electrophilic attack. It is highly expressed in many solid tumors, suggesting a role in cancer development and progression. However, the role of NQO1 in gastric cancer and its effect on cancer development and prognosis have not been fully investigated.

AIM

To investigate the clinical relevance of NQO1 protein expression in gastric cancer and to explore the potential of NQO1 to serve as a prognostic biomarker and therapeutic target.

METHODS

In this retrospective study, gastric cancer specimens of 175 patients who were treated between 1995 and 2011 were subjected to immunohistochemistry analyses for NQO1. The correlation of NQO1 expression with gastric cancer prognosis and clinical and pathological parameters was investigated.

RESULTS

NQO1 protein was overexpressed in 59.43% (104/175) of the analyzed samples. Overexpression of NQO1 was associated with a significantly inferior prognosis. In addition, multivariate analysis suggested that NQO1 overexpression, along with tumor stage and patient age, are prominent prognostic biomarkers for gastric cancer. Moreover, NQO1 overexpression was correlated to a better response to 5-fluorouracil (5-FU)-based adjuvant chemotherapy.

CONCLUSION

NQO1 overexpression is associated with a significantly poor prognosis and better response to 5-FU in patients with gastric cancer. These findings are relevant for improving therapeutic approaches for gastric cancer patients.

Discovery of Natural Products Targeting NQO1 via an Approach Combining Network-Based Inference and Identification of Privileged Substructures

NAD(P)H:quinone oxidoreductase 1 (NQO1) has been shown to be a potential therapeutic target for various human diseases, such as cancer and neurodegenerative disorders. Recent advances in computational methods, especially network-based methods, have made it possible to identify novel compounds for a target with high efficiency and low cost. In this study, we designed a workflow combining network-based methods and identification of privileged substructures to discover new compounds targeting NQO1 from a natural product library. According to the prediction results, we purchased 56 compounds for experimental validation. Without the assistance of privileged substructures, 31 compounds (31/56 = 55.4%) showed IC₅₀ < 100 μM, and 11 compounds (11/56 = 19.6%) showed IC₅₀ < 10 μM. With the assistance of privileged substructures, the two success rates were increased to 61.8 and 26.5%, respectively. Seven natural products further showed inhibitory activity on NQO1 at the cellular level, which may serve as lead compounds for further development. Moreover, network analysis revealed that osthole may exert anticancer effects against multiple cancer types by inhibiting not only carbonic anhydrases IX and XII but also NQO1. Our workflow and computational methods can be easily applied in other targets and become useful tools in drug discovery and development.

Sustained high expression of NRF2 and its target genes induces dysregulation of cellular proliferation and apoptosis is associated with arsenite-induced malignant transformation of human bronchial epithelial cells

In arsenic toxicity, activation of the erythroid 2-related factor 2 (NRF2) pathway is regarded as a driver of cancer development and progression; however, the mechanisms by which NRF2 gene expression regulates cell cycle progression and mediates pathways of cellular proliferation and apoptosis in arsenic-induced lung carcinogenesis are poorly understood. In this study, we explored the regulatory functions of NRF2 expression and its target genes in immortalized human bronchial epithelial (HBE) cells continuously exposed to 1.0 μM sodium arsenite over approximately 43 passages (22 weeks). The experimental treatment induced malignant transformation in HBE cells, characterized by increased cellular proliferation and soft agar clone formation, as well as cell migration, and accelerated cell cycle progression from G0/G1 to S phase with increased levels of cyclin E-CDK2 complex,decreased cellular apoptosis rate. Moreover, we observed a sustained increase in NRF2 protein levels and those of its target gene products (NQO1, BCL-2) with concurrently decreased expression of apoptosis-related proteins (BAX, Cleaved-caspase-3/Caspase-3 and CHOP) and increased expression of the anti-apoptotic protein MCL-1. Silencing NRF2 expression with small interfering RNA (siRNA) in arsenite-transformed (T-HBE) cells was shown to reverse the malignant phenotype. Further, siRNA silencing of NQO1 significantly decreased levels of the cyclin E-CDK2 complex, inhibiting G0/G1 to S phase cell cycle progression and transformation to the T-HBE phenotypes. This study demonstrated a novel role for the NRF2/NQO1 signaling pathway in mediating arsenite-induced cell transformation by increasing the expression of cyclin E-CDK2, and accelerating the cell cycle and cell proliferation. Arsenite promotes activation of the NRF2/BCL-2 signaling pathway inhibited CHOP increasing cellular resistance to apoptosis and further promoting malignant transformation.

The expression of zebrafish NAD(P)H:quinone oxidoreductase 1(nqo1) in adult organs and embryos

NQO1, NAD(P)H: quinone oxidoreductase 1, was first identified in rat and its role has been extensively studied. Even the roles of NQO1 in the maintenance of physiological function and disease were largely addressed, whether the tissue specific functions of the NQO1 in organ development remains unknown. In the current study, we identified two NQO1 isoforms (isoform 1 and isoform 2) and examined the expression of nqo1 variants in adult zebrafish organs and embryos at different stages. In adult organs, RT-PCR result indicated that nqo1 variant 1 was mainly expressed in stomach and intestine, while nqo1 variant 2 was expressed in all organs investigated except for heart. Further, RT-PCR result showed that the nqo1 variant 1 and variant 2 were expressed at all the embryonic stages, but nqo1 variant 1 expression level was much lower than that of nqo1 variant 2. To specifically examine the expression pattern of these two different nqo1 variants, we did whole mount in situ hybridization and the results demonstrated that, both of them were maternally expressed at 8-cell stage, and they were all expressed ubiquitously at early stage. At 24 hpf, nqo1 variant 2 was mainly expressed in yolk cells, and slightly in head and eyes. At 48 hpf, nqo1 variant 2 was restricted in lateral line neuromasts. From 72 hpf to 144 hpf, nqo1 variant 2 was mainly restricted in branchial arch, liver, swimming bladder and lateral line neuromasts, while from 124 hpf to 192 hpf, nqo1 variant 2 only restricted in liver, and disappeared in lateral line neuromasts. On the contrary, at the late embryonic stage, nqo1 variant 1 was only expressed in liver and swimming bladder while not in branchial arch and lateral line neuromasts. In conclusion, we systematically analyzed the expression pattern of nqo1 variant 1 and variant 2 in zebrafish at different embryonic stages, and our data implied the possible role of nqo1 in regulating liver, branchial arch and lateral neuromasts development.

Covalent-Assembly Based Fluorescent Probes for Detection of hNQO1 and Imaging in Living Cells

Human NAD(P)H: quinone oxidoreductase (hNQO1) is an important biomarker for human malignant tumors. Detection of NQO1 accurately is of great significance to improve the early diagnosis of cancer and prognosis of cancer patients. In this study, based on the covalent assembly strategy, hNQO1-activated fluorescent probes 1 and 2 are constructed by introducing coumarin precursor 2-cyano-3-(4-(diethylamino)-2-hydroxyphenyl) acrylic acid and self-immolative linkers. Under reaction with hNQO1 and NADH, turn-on fluorescence appears due to in-situ formation of the organic fluorescent compound 7-diethylamino-3-cyanocoumarin, and fluorescent intensity changes significantly. Probe 1 and 2 for detection of hNQO1 are not interfered by other substances and have low toxicity in cells. In addition to quantitative detection of hNQO1 in vitro, they have also been successfully applied to fluorescent imaging in living cells.

Therapeutic Strategies and Biomarkers to Modulate PARP Activity for Targeted Cancer Therapy

Poly-(ADP-ribose) polymerase 1 (PARP1) is commonly known for its vital role in DNA damage response and repair. However, its enzymatic activity has been linked to a plethora of physiological and pathophysiological transactions ranging from cellular proliferation, survival and death. For instance, malignancies with BRCA1/2 mutations heavily rely on PARP activity for survival. Thus, the use of PARP inhibitors is a well-established intervention in these types of tumors. However, recent studies indicate that the therapeutic potential of attenuating PARP1 activity in recalcitrant tumors, especially where PARP1 is aberrantly overexpressed and hyperactivated, may extend its therapeutic utility in wider cancer types beyond BRCA-deficiency. Here, we discuss treatment strategies to expand the tumor-selective therapeutic application of PARP inhibitors and novel approaches with predictive biomarkers to perturb NAD⁺ levels and hyperPARylation that inactivate PARP in recalcitrant tumors. We also provide an overview of genetic alterations that transform non-BRCA mutant cancers to a state of "BRCAness" as potential biomarkers for synthetic lethality with PARP inhibitors. Finally, we discuss a paradigm shift for the use of novel PARP inhibitors outside of cancer treatment, where it has the potential to rescue normal cells from severe oxidative damage during ischemia-reperfusion injury induced by surgery and radiotherapy.

Characterization of a highly specific NQO1-activated near-infrared fluorescent probe and its application for in vivo tumor imaging

The Near-infrared Fluorescence (NIRF) molecular imaging of cancer is known to be superior in sensitivity, deeper penetration, and low phototoxicity compared to other imaging modalities. In view of an increased need for efficient and targeted imaging agents, we synthesized a NAD(P)H quinone oxidoreductase 1 (NQO1)-activatable NIR fluorescent probe (NIR-ASM) by conjugating dicyanoisophorone (ASM) fluorophore with the NQO1 substrate quinone propionic acid (QPA). The probe remained non-fluorescent until activation by NQO1, whose expression is largely limited to malignant tissues. With a large Stokes shift (186 nm) and a prominent near-infrared emission (646 nm) in response to NQO1, NIR-ASM was capable of monitoring NQO1 activity in vitro and in vivo with high specificity and selectivity. We successfully employed the NIR-ASM to differentiate cancer cells from normal cells based on NQO1 activity using fluorescence microscopy and flow cytometry. Chemical and genetic approaches involving the use of ES936, a specific inhibitor of NQO1 and siRNA and gene transfection procedures unambiguously demonstrated NQO1 to be the sole target activating the NIR-ASM in cell cultures. NIR-ASM was successfully used to detect and image the endogenous NQO1 in three live tumor-bearing mouse models (A549 lung cancer, Lewis lung carcinoma, and MDMAMB 231 xenografts) with a high signal-to-low noise ratiometric NIR fluorescence response. When the NQO1-proficient A549 tumors and NQO1-deficient MDA-MB-231 tumors were developed in the same animal, only the A549 malignancies activated the NIR-ASM probe with a strong signal. Because of its high sensitivity, rapid activation, tumor selectivity, and nontoxic properties, the NIR-ASM appears to be a promising agent with clinical applications.

Cancer-Specific Biomarker hNQO1-Activatable Fluorescent Probe for Imaging Cancer Cells In Vitro and In Vivo

Human NAD(P)H quinone oxidoreductase-1 (hNQO1) is an important cancer-related biomarker, which shows significant overexpression in malignant cells. Developing an effective method for detecting NQO1 activity with high sensitivity and selectivity in tumors holds a great potential for cancer diagnosis, treatment, and management. In the present study, we report a new dicyanoisophorone (DCP) based fluorescent probe (NQ-DCP) capable of monitoring hNQO1 activity in vitro and in vivo in both ratiometric and turn-on model. NQ-DCP was prepared by conjugating dicyanoisophorone fluoroprobe with hNQO1 activatable quinone propionic acid (QPA), which remain non-fluorescent until activation by tumor-specific hNQO1. NQ-DCP featured a large Stokes shift (145 nm), excellent biocompatibility, cell permeability, and selectivity towards hNQO1 allowed to differentiate cancer cells from healthy cells. We have successfully employed NQ-DCP to monitor non-invasive endogenous hNQO1 activity in brain tumor cells in vitro and in xenografted tumors developed in nude mice.

Effect of β-Eudesmol on NQO1 suppression-enhanced sensitivity of cholangiocarcinoma cells to chemotherapeutic agents

Background

Cholangiocarcinoma (CCA), an epithelial malignancy of the biliary tree, is one of the aggressive cancers with poor prognosis and unsatisfactory response to chemotherapy with acquired resistance. NAD(P)H-quinone oxidoreductase 1 (NQO1), an antioxidant/detoxifying enzyme, plays important roles in chemo-resistance and proliferation in several cancer cells. The study aimed to investigate the inhibitory effect of β-eudesmol on NQO1 enhanced chemotherapeutic effects of 5-fluorouracil (5-FU) and doxorubicin (DOX) in the high NQO1-expressing human CCA cell line, NQO1-KKU-100. In addition, the molecular events associated with the inhibition of the cell proliferation, cell migration, and induction of apoptosis were investigated.

Methods

Human CCA KKU-100 cells were exposed to β-eudesmol at various concentrations. NQO1 enzyme activity and protein expression were measured by enzymatic assay and Western blot analysis, respectively. Sulforhodamine B (SRB) assay and wound healing assay were performed to detect the inhibitory effect of β-eudesmol on cell proliferation, cell migration, and sensitivity to 5-FU and DOX. Apoptotic induction was detected by flow cytometry with annexin V/PI and DAPI nuclear staining. Caspase 3/7 activation was determined by fluorescence microscopy. The mechanism of enhanced chemo-sensitivity was evaluated by Western blot analysis.

Results

β-Eudesmol significantly suppressed NQO1 enzyme activity (both in KKU-100 cells and cell lysates) and protein expression in KKU-100 cells in a concentration-dependent manner. β-Eudesmol exhibited potent cytotoxicity on KKU-100 cells with mean ± SD IC₅₀ values of 47.62 ± 9.54 and 37.46 ± 12.58 μM at 24 and 48 h, respectively. In addition, it also potentiated the cytotoxic activities and inhibitory activities of 5-FU and DOX on cell migration through induction of cell apoptosis and activation of caspase 3/7. Western blot analysis suggested that β-eudesmol enhanced chemosensitivity was associated with the suppression of NQO1 protein and activation of Bax/Bcl-2 protein expression ratio in CCA cells.

Conclusions

β-Eudesmol may serve as a potential anti-CCA candidate particularly when used in combination with conventional chemotherapeutics. The mechanisms involved may be mediated via NQO1 suppression-related apoptosis pathway.

Antifibrogenic effect of melatonin in rats with experimental liver cirrhosis induced by carbon tetrachloride

Background and Aim

Liver diseases are a major public health problem, accounting for a significant number of hospital visits and admissions and an increasing mortality rate. Melatonin (MLT) is a powerful antioxidant molecule that has been shown to be beneficial under various conditions. The objective was to evaluate the effect of MLT on experimental liver cirrhosis induced by carbon tetrachloride (CCl₄) in rats.

Methods

Twenty male Wistar rats (230–250 g) were divided into four groups. I: control group (CO); II: CO + MLT; III: CCl₄; and IV: CCl₄ + MLT. CCl₄ was administered intraperitoneally (i.p.) as follows: 10 doses every 5 days, 10 doses every 4 days, and 7 doses every 3 days. MLT was administered i.p. at a dose of 20 mg/kg from the 10th week to the end of the experiment (16th week).

Results

In the CCl₄ + MLT group, we found that MLT caused a decrease in the level of F2‐isoprostanes and NQO1 expression. We also found that MLT reduced the inflammatory process as shown by decreased expressions of NF‐KB/p65 and inducible nitric oxide synthase (iNOS) and a smaller amount of inflammatory infiltrate. MLT reduced the expression of transforming growth factor beta1 (TGF‐β1), alpha‐smooth muscle actin (α‐SMA), and vascular endothelial growth factor (VEGF). Picrosirius staining showed that MLT decreases fibrosis.

Conclusion

MLT has a potent antifibrogenic effect, modulating the parameters of oxidative stress, angiogenesis, and inflammation.

Dual-negative expression of Nrf2 and NQO1 predicts superior outcomes in patients with non-small cell lung cancer

Functional studies in non-small cell lung cancer (NSCLC) patients revealed that hyperactivation of the NF-E2-related factor 2 (Nrf2) pathway facilitates tumor growth. We examined the usefulness of Nrf2 and NQO1 as indicators of prognosis in NSCLC. Tumor and adjacent non-tumor tissue samples were collected from 215 NSCLC patients who had tumor resections between 2006 and 2011. Immunohistochemistry was performed to detect Nrf2 or NQO1 expression. The correlation between Nrf2 or NQO1 expression and survival outcomes was evaluated using the Kaplan-Meier method and Cox proportional hazards regression model. Levels of Nrf2 and NQO1 were elevated in tumor tissues. In particular, Nrf2 was elevated in nearly all tumor cells. NQO1 expression positively correlated with Nrf2 expression (P = 0.039). Nrf2 expression positively correlated with lymph node metastasis (P = 0.001) and negatively correlated with tumor differentiation (P = 0.032). As compared with either Nrf2 or NQO1 alone, dual-negative expression of Nrf2 and NQO1 was more predictive of superior overall survival (P = 0.020) and disease free survival (P = 0.037). Subgroup analyses showed that females, nonsmokers, and patients with advanced-stage NSCLC were suitable populations in which to evaluate prognosis based on Nrf2 and NQO1 co-expression. These results indicate that dual-negative expression of Nrf2 and NQO1 is predictive of a better prognosis in NSCLC patients.

Prognostic implication of NQO1 overexpression in hepatocellular carcinoma

To explore the role of NQO1 overexpression for prognostic implication in hepatocellular carcinoma (HCC), NQO1 mRNA levels were detected in HCC fresh tissue samples of HCC and nontumor tissues, respectively. One hundred fifty-six cases of HCC meeting strict follow-up criteria were selected for immunohistochemical staining of NQO1 protein. Correlations between NQO1 overexpression and clinicopathological features of HCC were evaluated using χ² tests, survival rates were calculated using the Kaplan-Meier method, and the relationship between prognostic factors and patient 5-year survival was analyzed using Cox proportional hazards analysis. In results, the levels of NQO1 mRNA were significantly up-regulated in 14 fresh tissue samples of HCC. Immunohistochemical analysis showed that the NQO1 expression and overexpression rates were significantly higher in HCC samples compared with either adjacent nontumor tissues or normal liver tissues. NQO1 overexpression correlated to tumor size, venous infiltration and late pTNM stage of HCC. NQO1 overexpression was also related to low disease-free survival and 5-year survival rates. In the late-stage group, disease-free and 5-year survival rates of patients with NQO1 overexpression were significantly lower than those of patients without NQO1 expression. Further analysis using a Cox proportional hazards regression model revealed that NQO1 expression emerged as a significant independent hazard factor for the 5-year survival rate of patients with HCC. Therefore, NQO1 plays an important role in the progression of HCC. NQO1 may potentially be used as an independent biomarker for prognostic evaluation of HCC.

Genetic association of NAD(P)H quinone oxidoreductase (NQO1*2) polymorphism with NQO1 levels and risk of diabetic nephropathy

NAD(P)H quinone oxidoreductase 1 (NQO1) catalyzes reactions having a cyto-protective effect against redox cycling and oxidative stress. A single base polymorphism (C/T) at nucleotide 609 of the NQO1 gene impairs the stability and function of its protein. Its role in the development of diabetic nephropathy (DN) has not been deciphered. Therefore, this study aimed to evaluate the association of NQO1*2 (rs1800566) polymorphism with plasma NQO1 levels and DN. This study screened 600 participants including healthy controls (HC), type 2 diabetes mellitus without complications (T2DM) and diabetic nephropathy (DN): 200 each for studying NQO1*2 gene polymorphism using the PCR-RFLP. Plasma NQO1 levels were measured by ELISA. Analysis of variance and logistic regression were used to evaluate the association of NQO1 polymorphism with plasma NQO1 levels and DN. The allelic frequencies of NQO1*1/NQO1*2 were 0.88/0.12 in HC, 0.765/0.235 in T2DM and 0.65/0.35 in DN. Carriers of the NQO1*2 allele had significantly lower plasma NQO1 levels (p<0.05) and revealed higher risk towards the development of DN (OR=1.717, p=0.010). NQO1*2 SNP is a functional polymorphism having a significant effect on NQO1 levels. Our results indicate that NQO1*2 genotype may increase susceptibility to DN in north Indian subjects with T2DM.

Clinicopathological implications of NQO1 overexpression in the prognosis of pancreatic adenocarcinoma

Nicotinamide adenine dinucleotide phosphate: quinone oxidoreductase 1 (NQO1) protects cells from oxidative damage. NQO1 has been reported to be upregulated in numerous solid tumors, suggesting a role in carcinogenesis and tumor progression. The present study attempted to investigate the clinical prognostic significance of NQO1 overexpression in pancreatic ductal adenocarcinoma (PDAC). A total of 181 tissue specimens were studied, including 126 PDAC and 55 normal pancreas specimens, which were selected for immunohistochemical staining of NQO1 protein. Immunofluorescence staining was additionally performed to identify the subcellular localization of NQO1 protein in pancreatic cancer BxPC-3 cells. The association between NQO1 overexpression and the clinical features of PDAC were evaluated by χ² and Fisher's exact test. Overall survival of PDAC patients was calculated using Kaplan-Meier analysis. Univariate and multivariate analyses were performed using the Cox proportional hazards regression model. The NQO1 protein was mainly located in the cytoplasm and nucleus of BxPC-3 cells. The strongly positive rate of NQO1 expression in PDAC (65.9%, 83/126) was increased compared with that in normal pancreatic tissues (10.9%, 6/55). The positive rate of NQO1 protein was associated with grading, lymph node stage and tumor-node-metastasis (TNM) stage. Additionally, multivariate analysis suggested that NQO1 was a significant independent prognostic factor along with TNM stage in PDAC. In conclusion, high expression of NQO1 appears to be associated with PDAC progression, and may be an independent prognostic biomarker in PDAC.

Pharmacokinetics and derivation of an anticancer dosing regimen for the novel anti-cancer agent isobutyl-deoxynyboquinone (IB-DNQ), a NQO1 bioactivatable molecule, in the domestic felid species

Isobutyl-deoxynyboquinone (IB-DNQ) is a selective substrate for NAD(P)H:quinone oxidoreductase (NQO1), an enzyme overexpressed in many solid tumors. Following activation by NQO1, IB-DNQ participates in a catalytic futile reduction/reoxidation cycle with consequent toxic reactive oxygen species generation within the tumor microenvironment. To elucidate the potential of IB-DNQ to serve as a novel anticancer agent, in vitro studies coupled with in vivo pharmacokinetic and toxicologic investigations in the domestic felid species were conducted to investigate the tractability of IB-DNQ as a translationally applicable anticancer agent. First, using feline oral squamous cell carcinoma (OSCC) as a comparative cancer model, expressions of NQO1 were characterized in not only human, but also feline OSCC tissue microarrays. Second, IB-DNQ mediated cytotoxicity in three immortalized feline OSCC cell lines were studied under dose-dependent and sequential exposure conditions. Third, the feasibility of administering IB-DNQ at doses predicted to achieve cytotoxic plasma concentrations and biologically relevant durations of exposure were investigated through pharmacokinetic and tolerability studies in healthy research felines. Intravenous administration of IB-DNQ at 1.0-2.0 mg/kg achieved peak plasma concentrations and durations of exposure reaching or exceeding predicted in vitro cytotoxic concentrations. Clinical adverse side effects including ptyalism and tachypnea exhibited during and post-IV infusion of IB-DNQ were transient and tolerable. Additionally, IB-DNQ administration did not produce acute or delayed-onset unacceptable hematologic, non-hematologic, or off-target oxidative toxicities. Collectively, the findings reported here within provide important safety and pharmacokinetic data to support the continued development of IB-DNQ as a novel anticancer strategy for NQO1 expressing cancers.

Correlation between NAD(P)H: quinone oxidoreductase 1 C609T polymorphism and increased risk of esophageal cancer: evidence from a meta-analysis

NAD(P)H: quinone oxidoreductase 1 (NQO1) C609T gene polymorphisms have been reported to influence the risk for esophageal cancer (EC) in many studies. However, the results remain controversial and ambiguous. We performed a meta-analysis, which included 13 independent studies with a total of 2357 subjects, to examine the association between NQO1 C609T polymorphism and EC. The association was assessed by five different gene models. The overall analysis suggested that the variant allele and genotypes were significantly related to increased risk of EC (odds ratio [OR] T versus C = 1.15, 95% confidence interval [CI] 0.95-1.40, probability of rejection [POR] = 0.014; OR TT versus CC = 1.32, 95% CI 1.01-1.73, POR = 0.045; OR TC versus CC = 1.32, 95% CI 0.98-1.21, POR = 0.128; OR TT + TC versus CC = 1.10, 95% CI 1.00-1.20, POR = 0.05; OR TT versus CC + TC = 1.26, 95% CI 0.95-1.57, POR = 0.103). Sensitivity analysis confirmed the reliability of these findings. Our study shows that individuals carrying the NQO1 C609T variant allele and genotypes are more susceptible to EC.

The Ontogeny and Population Variability of Human Hepatic NADPH Dehydrogenase Quinone Oxido-Reductase 1 (NQO1)

The NADPH dehydrogenase quinone oxido-reductase 1 (NQO1) enzyme is an antioxidant and metabolic enzyme that performs two electron reduction of quinones and other chemicals. Based on the physiologic role(s) of NQO1, we hypothesized that expression and activity of this enzyme would vary with age and other demographic variables. Cytosols from 117 archived human livers were investigated for changes in NQO1 with age, sex, obesity, and ethnicity. Protein expression but not activity of NQO1 was weakly negatively correlated with age (Spearman r = -0.2, P = 0.03). No sex differences were observed for either protein expression or activity and for ethnicity; Caucasians had greater NQO1 activity than Asians (P < 0.05). Overweight children had statistically significantly higher NQO1 activity as compared with ideal weight children (P < 0.05) although this difference was not observed in adults. These findings establish that NQO1 is approximately as active in children as adults. However, modeled NQO1 clearance (both allometric and physiologically based pharmacokinetics) predicted maturation at 23 to 26 years. This is almost certainly an overestimate, with error in the model resulting from a small sample size and inability to scale for age-related changes in hepatic cellularity and/or cytosolic protein content, and indicates a delay in reaching maximum clearance through the NQO1 pathway that is affected by physiologic development as much, or more than, biochemical development. Obesity may increase hepatic NQO1 activity in children, which is likely a protective mechanism in oxidative stress, but may also have significant implications for drug and chemical disposition in obese children.

Deoxynyboquinones as NQO1-Activated Cancer Therapeutics

One of the major goals of cancer therapy is the selective targeting of cancer cells over normal cells. Unfortunately, even with recent advances, the majority of chemotherapeutics still indiscriminately kill all rapidly dividing cells. Although these drugs are effective in certain settings, their inability to specifically target cancer results in significant dose-limiting toxicities. One way to avoid such toxicities is to target an aspect of the cancer cell that is not shared by normal cells. A potential cancer-specific target is the enzyme NAD(P)H quinone oxidoreductase 1 (NQO1). NQO1 is a 2-electron reductase responsible for the detoxification of quinones. Its expression is typically quite low in normal tissue, but it has been found to be greatly overexpressed in many types of solid tumors, including lung, breast, pancreatic, and colon cancers. This overexpression is thought to be in response to the higher oxidative stress of the cancer cell, and it is possible that NQO1 contributes to tumor progression. The overexpression of NQO1 and its correlation with poor patient outcome make it an intriguing target. Although some have explored inhibiting NQO1 as an anticancer strategy, this has generally been unsuccessful. A more promising strategy is to utilize NQO1 substrates that are activated upon reduction by NQO1. For example, in principle, reduction of a quinone can result in a hydroquinone that is a DNA alkylator, protein inhibitor, or reduction-oxidation cycler. Although there are many proposed NQO1 substrates, head-to-head assays reveal only two classes of compounds that convincingly induce cancer cell death through NQO1-mediated activation. In this Account, we describe the discovery and development of one of these compounds, the natural product deoxynyboquinone (DNQ), an excellent NQO1 substrate and anticancer agent. A modular synthesis of DNQ was developed that enabled access to the large compound quantities needed to conduct extensive mechanistic evaluations and animal experiments. During these evaluations, we found that DNQ is an outstanding NQO1 substrate that is processed much more efficiently than other putative NQO1 substrates. Importantly, its anticancer activity is strictly dependent on the overexpression of active NQO1. Using previous crystal structures of NQO1, novel DNQ derivatives were designed that are also excellent NQO1 substrates and possess properties that make them more attractive than the parent natural product for translational development. Given their selectivity, potency, outstanding pharmacokinetic properties, and the ready availability of diagnostics to assess NQO1 in patients, DNQ and its derivatives have considerable potential as personalized medicines for the treatment of cancer.

Correlation of NQO1 and Nrf2 in Female Genital Tract Cancer and Their Precancerous Lesions (Cervix, Endometrium and Ovary)

Background

NAD (P) H/quinone oxidoreductase 1 (NQO1) is a metabolizing enzyme that detoxifies chemical stressors and antioxidants. Nuclear factor erythroid 2-related factor 2 (NrF2) is an important transcriptional activator involved in the cellular defense mechanisms against oxidative stress.

Methods

The immunohistochemical expression of NQO1 and Nrf2 in 80 cervical, 80 endometrial and 100 ovarian specimens with different lesions was studied. Then we study the relation of both NQO1 and Nrf2 expression and clinicopathological features of carcinoma cases.

Results

Immunohistochemical stain showed that NQO1 and Nrf2 were highly expressed in carcinoma compared with normal and precancerous lesions. Significant positive correlations were found between the mean expression of NQO1 and Nrf2 in different lesions. Moreover, there was significant correlation between the high level of NQO1 and Nrf2 expression and high tumor grade in cervical and endometrial carcinoma cases. Nrf2 expression was significant with advanced stage in endometrial and ovarian carcinomas.

Conclusions

NQO1 and Nrf2 might be new biomarkers for early diagnosis and prognostic evaluation as well as being targets for therapy in patients with tumors in female genital tract.

High expression of NQO1 is associated with poor prognosis in serous ovarian carcinoma

Background

NAD(P)H:quinone oxidoreductase (NQO1) is a flavoprotein that catalyzes two-electron reduction and detoxification of quinones and its derivatives. NQO1 catalyzes reactions that have a protective effect against redox cycling, oxidative stress and neoplasia. High expression of NQO1 is associated with many solid tumors including those affecting the colon, breast and pancreas; however, its role in the progression of ovarian carcinoma is largely undefined. This study aimed to investigate the clinicopathological significance of high NQO1 expression in serous ovarian carcinoma.

Methods

NQO1 protein expression was assessed using immunohistochemical (IHC) staining in 160 patients with serous ovarian carcinoma, 62 patients with ovarian borderline tumors and 53 patients with benign ovarian tumors. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect NQO1 mRNA expression levels. The correlation between high NQO1 expression and clinicopathological features of ovarian carcinoma was evaluated by Chi-square and Fisher’s exact test. Overall survival (OS) rates of all of ovarian carcinoma patients were calculated using the Kaplan-Meier method, and univariate and multivariate analyses were performed using the Cox proportional hazards regression model.

Results

NQO1 protein expression in ovarian carcinoma cells was predominantly cytoplasmic. Strong, positive expression of NQO1 protein was observed in 63.8% (102/160) of ovarian carcinomas, which was significantly higher than in borderline serous tumors (32.3%, 20/62) or benign serous tumors (11.3%, 6/53). Importantly, the rate of strong, positive NQO1 expression in borderline serous tumors was also higher than in benign serous tumors. High expression of NQO1 protein was closely associated with higher histological grade, advanced clinical stage and lower OS rates in ovarian carcinomas. Moreover, multivariate analysis indicated that NQO1 was a significant independent prognostic factor, in addition to clinical stage, in patients with ovarian carcinoma.

Conclusions

NQO1 is frequently upregulated in ovarian carcinoma. High expressin of NQO1 protein may be an effective biomarker for poor prognostic evaluation of patients with serous ovarian carcinomas.

NQO1 protein expression predicts poor prognosis of non-small cell lung cancers

BACKGROUND

High-level expression of

NAD(P)H

quinoneoxidoreductase 1 (NQO1) has been correlated with many types of human cancers, suggesting that NQO1 plays important roles in tumor occurrence and progression. This study attempted to explore the role of NQO1 in tumor progression and prognostic evaluation of non-small cell lung cancer (NSCLC).

METHODS

Total 164 tissue samples, including 150 NSCLC paired with the adjacent non-tumor tissues and 14 normal lung tissues, were picked-up for immunohistochemical (IHC) staining of the NQO1 protein, and immunofluorescence (IF) staining was also performed to detect the subcellular localization of the NQO1 protein in A549 human lung cancer cells. The correlation between NQO1 expression and clinicopathological characteristics were evaluated by Chi-square test and Fisher's exact tests. The disease-free survival (DFS) and overall survival (OS) rates of NSCLC patients were calculated by the Kaplan-Meier method, and univariate and multivariate analyses were performed using the Cox proportional hazards regression model.

RESULTS

The NQO1 protein showed a mainly cytoplasmic staining pattern in lung cancer cells, including adenocarcinoma and squamous cell carcinoma (SCC). Both positive rate and strongly positive rate of NQO1 protein expression were significantly higher in NSCLC (59.3% and 28.0%) than that in adjacent non tumor (8.0% and 1.3%) and normal lung tissues (0%). The positive rate of NQO1 was related with clinical stage and lymph node metastasis, and the strongly positive rate of NQO1 protein was significantly correlated with tumor size, poor differentiation, advanced clinical stage and lymph node metastasis in NSCLC. Additionally, survival analyses showed that the patients with NQO1 positive expression had lower OS rates compared with those with NQO1 negative expression in the groups of T1-2, T3-4, without LN metastasis and stage I-II of NSCLC, respectively; however, in the groups of patients with LN metastasis or III-IV stages, OS rate was not correlated with NQO1 expression status. Moreover, multivariate analysis suggested that NQO1 emerged as a significant independent prognostic factor along with tumor size, differentiation, lymph node metastasis and clinical stage in patients with NSCLC.

CONCLUSIONS

NQO1 is upregulated in NSCLC, and it may be a useful poor prognostic biomarker and a potential therapeutic target for patients with NSCLC.

High GOLPH3 expression is associated with poor prognosis and invasion of hepatocellular carcinoma

Golgi phosphoprotein 3 (GOLPH3) overexpression has previously been associated with the progression of several solid tumors, which resulted in adverse clinical outcomes. The present study aimed to determine the expression and prognostic significance of GOLPH3 in human hepatocellular carcinoma (HCC). GOLPH3 expression was examined using western blot analysis of 30 paired samples of HCC and adjacent non‑cancerous liver tissues. GOLPH3 expression levels were also assessed using immunohistochemistry in 180 HCC samples and paired controls. In addition, the association of GOLPH3 expression with clinicopathological features and clinical outcome was analyzed. Furthermore, the effect of GOLPH3 on HCC cell proliferation and invasion were determined. Western blot analysis revealed that GOLPH3 expression was significantly elevated in HCC tissue compared with that of the matched adjacent non‑cancerous liver tissue. In addition, the results of the immunohistochemical analysis demonstrated that GOLPH3 expression was positively correlated with the Edmondson‑Steiner grade (P=0.006), vascular invasion (P=0.002) and serum α feto‑protein levels (P=0.015). GOLPH3 expression was found to be an independent factor for predicting the poor overall survival of HCC patients (hazard ratio, 2.01; 95% confidence interval, 1.26‑3.64; P=0.025). In addition, GOLPH3 silencing inhibited the proliferation, invasion and migration of HCC cell lines in vitro. In conclusion, the results of the present study demonstrated that high GOLPH3 levels may be a potential biomarker for the poor prognosis of patients with HCC.

Combination of unsaturated fatty acids and ionizing radiation on human glioma cells: cellular, biochemical and gene expression analysis

Background

Based on previous observations a potential resort in the therapy of the particularly radioresistant glioma would be its treatment with unsaturated fatty acids (UFAs) combined with irradiation.

Methods

We evaluated the effect of different UFAs (arachidonic acid (AA), docosahexaenoic acid (DHA), gamma-linolenic acid (GLA), eicosapentaenoic acid (EPA) and oleic acid (OA)) on human U87 MG glioma cell line by classical biochemical end-point assays, impedance-based, real-time cellular and holographic microscopic analysis. We further analyzed AA, DHA, and GLA at morphological, gene and miRNA expression level.

Results

Corresponding to LDH-, MTS assays and real-time cytoxicity profiles AA, DHA, and GLA enhanced the radio sensitivity of glioma cells. The collective application of polyunsaturated fatty acids (PUFAs) and irradiation significantly changed the expression of EGR1, TNF-α, NOTCH1, c-MYC, TP53, HMOX1, AKR1C1, NQO1, while up-regulation of GADD45A, EGR1, GRP78, DDIT3, c-MYC, FOSL1 were recorded both in response to PUFA treatment or irradiation alone. Among the analyzed miRNAs miR-146 and miR-181a were induced by DHA treatment. Overexpression of miR-146 was also detected by combined treatment of GLA and irradiation.

Conclusions

Because PUFAs increased the radio responsiveness of glioma cells as assessed by biochemical and cellular assays, they might increase the therapeutic efficacy of radiation in treatment of gliomas. We demonstrated that treatment with DHA, AA and GLA as adjunct to irradiation up-regulated the expression of oxidative-stress and endoplasmic reticulum stress related genes, and affected NOTCH1 expression, which could explain their additive effects.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-511X-13-142) contains supplementary material, which is available to authorized users.

NQO1 overexpression is associated with poor prognosis in squamous cell carcinoma of the uterine cervix

Background

NQO1 (NAD(P)H: quinone oxidoreductase-1), located on chromosome 16q22, functions primarily to protect normal cells from oxidant stress and electrophilic attack. Recent studies have revealed that NQO1 is expressed at a high level in most human solid tumors including those of the colon, breast, pancreas, ovaries and thyroid, and it has also been detected following the induction of cell cycle progression and proliferation of melanoma cells. In this study, we aimed to investigate the clinicopathological significance of upregulated NQO1 protein expression in squamous cell carcinomas (SCCs) of the uterine cervix.

Methods

The localization of the NQO1 protein was determined in the SiHa cervical squamous cancer cell line using immunofluorescence (IF) staining, and immunohistochemical (IHC) staining performed on paraffin-embedded cervical SCC specimens from 177 patients. For comparison, 94 cervical intraepithelial neoplasia (CIN) and 25 normal cervical epithelia samples were also included. QRT-PCR was performed on RNA from fresh tissues to detect NQO1 mRNA expression levels, and HPV infection status was genotyped using oligonucleotide microarray. Disease-free survival (DFS) and 5-year overall survival (OS) rates for all cervical SCC patients were calculated using the Kaplan–Meier method, and univariate and multivariate analysis was performed using the Cox proportional hazards regression model.

Results

The NQO1 protein showed a mainly cytoplasmic staining pattern in cervical cancer cells, and only three cases of cervical SCC showed a nuclear staining pattern. The strongly positive rate of NQO1 protein expression was significantly higher in cervical SCCs and CINs than in normal cervical epithelia. High-level NQO1 expression was closely associated with poor differentiation, late-stage, lymph node metastasis and high-risk for HPV infection. Additionally, high-level NQO1 expression was associated with lower DFS and 5-year OS rates, particularly for patients with early-stage cervical SCCs. Furthermore, Cox analysis revealed that NQO1 expression emerged as a significant independent hazard factor for DFS rate in patients with cervical SCC.

Conclusions

NQO1 overexpression might be an independent biomarker for prognostic evaluation of cervical SCCs.

Clinical implications of high NQO1 expression in breast cancers

Background

NAD (P) H: quinone oxidoreductase 1 (NQO1) is a xenobiotic metabolizing enzyme that detoxifies chemical stressors and antioxidants, providing cytoprotection in normal tissues. However, high-level expression of NQO1 has been correlated with numerous human malignancies, suggesting a role in carcinogenesis and tumor progression. This study aimed to explore the clinicopathological significance of NQO1 and as a prognostic determinant in breast cancer.

Methods

A total of 176 breast cancer patients with strict follow-up, 45 ductal carcinoma in situ (DCIS), 22 hyperplasia and 52 adjacent non-tumor breast tissues were selected for immunohistochemical staining of NQO1 protein. Immunofluorescence staining was also performed to detect the subcellular localization of NQO1 protein in MCF-7 breast cancer cells. Eight fresh breast cancers paired with adjacent non-tumor tissues were quantified using real time RT-PCR (qRT-PCR) and western blot. The correlations between NQO1 overexpression and the clinical features of breast cancer were evaluated using chi-square test and Fisher’s exact tests. The survival rate was calculated using the Kaplan–Meier method, and the relationship between prognostic factors and patient survival was also analyzed by the Cox proportional hazards models.

Results

NQO1 protein showed a mainly cytoplasmic staining pattern in breast cancer. The strongly positive rate of NQO1 protein was 61.9% (109/176) in breast cancer, and was significantly higher than in DCIS (31.1%, 14/45), hyperplasia tissues (13.6%, 3/22) and adjacent non-tumor tissues (13.5%, 7/52). High-level expression of NQO1 protein was correlated with late clinical stage, poor differentiation, lymph node metastasis, Her2 expression and disease-free and 10-year overall survival rates in breast cancer. Moreover, multivariate analysis suggested that NQO1 emerged as a significant independent prognostic factor along with clinical stage and Her2 expression status in patients with breast cancer.

Conclusions

High-level expression of NQO1 appears to be associated with breast cancer progression, and may be a potential biomarker for poor prognostic evaluation of breast cancers.