Dual Inhibition of NOX2 and Receptor Tyrosine Kinase by BJ-1301 Enhances Anticancer Therapy Efficacy via Suppression of Autocrine-Stimulatory Factors in Lung Cancer

Structure, Activation, and Regulation of NOX2: At the Crossroad between the Innate Immunity and Oxidative Stress-Mediated Pathologies

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) is a multisubunit enzyme complex that participates in the generation of superoxide or hydrogen peroxide (H₂O₂) and plays a key role in several biological functions. Among seven known NOX isoforms, NOX2 was the first identified in phagocytes but is also expressed in several other cell types including endothelial cells, platelets, microglia, neurons, and muscle cells. NOX2 has been assigned multiple roles in regulating many aspects of innate and adaptive immunity, and human and mouse models of NOX2 genetic deletion highlighted this key role. On the other side, NOX2 hyperactivation is involved in the pathogenesis of several diseases with different etiologies but all are characterized by an increase in oxidative stress and inflammatory process. From this point of view, the modulation of NOX2 represents an important therapeutic strategy aimed at reducing the damage associated with its hyperactivation. Although pharmacological strategies to selectively modulate NOX2 are implemented thanks to new biotechnologies, this field of research remains to be explored. Therefore, in this review, we analyzed the role of NOX2 at the crossroads between immunity and pathologies mediated by its hyperactivation. We described (1) the mechanisms of activation and regulation, (2) human, mouse, and cellular models studied to understand the role of NOX2 as an enzyme of innate immunity, (3) some of the pathologies associated with its hyperactivation, and (4) the inhibitory strategies, with reference to the most recent discoveries.

Redox Interactions in Chemo/Radiation Therapy-induced Lung Toxicity; Mechanisms and Therapy Perspectives

Lung toxicity is a key limiting factor for cancer therapy, especially lung, breast, and esophageal malignancies. Radiotherapy for chest and breast malignancies can cause lung injury. However, systemic cancer therapy with chemotherapy may also induce lung pneumonitis and fibrosis. Radiotherapy produces reactive oxygen species (ROS) directly via interacting with water molecules within cells. However, radiation and other therapy modalities may induce the endogenous generation of ROS and nitric oxide (NO) by immune cells and some nonimmune cells such as fibroblasts and endothelial cells. There are several ROS generating enzymes within lung tissue. NADPH Oxidase enzymes, cyclooxygenase-2 (COX-2), dual oxidases (DUOX1 and DUOX2), and the cellular respiratory system in the mitochondria are the main sources of ROS production following exposure of the lung to anticancer agents. Furthermore, inducible nitric oxide synthase (iNOS) has a key role in the generation of NO following radiotherapy or chemotherapy. Continuous generation of ROS and NO by endothelial cells, fibroblasts, macrophages, and lymphocytes causes apoptosis, necrosis, and senescence, which lead to the release of inflammatory and pro-fibrosis cytokines. This review discusses the cellular and molecular mechanisms of redox-induced lung injury following cancer therapy and proposes some targets and perspectives to alleviate lung toxicity.

Synthesis of Pyridoxine-Derived Dimethylpyridinols Fused with Aminooxazole, Aminoimidazole, and Aminopyrrole

Described in this paper are studies on the preparation of three classes of dimethylpyridinols derived from pyridoxine fused with aminooxazole, aminoimidazole, and aminopyrrole. The key feature of this synthetic strategy is the manipulation of hydroxymethyl moiety of C(5)-position of the pyridoxine starting material along with the installation of an amino group at C(6)-position. Efficient and practical synthesis for the oxazole- and imidazole-fused targets was accomplished, while the instability of the pyrrole-fused one was observed.

Comparison of COVID-19 and Lung Cancer via Reactive Oxygen Species Signaling

COVID-19 and lung cancer are two severe pulmonary diseases that cause millions of deaths globally each year. Understanding the dysregulated signaling pathways between them can benefit treating the related patients. Recent studies suggest the critical role of reactive oxygen species (ROS) in both diseases, indicating an interplay between them. Here we reviewed references showing that ROS and ROS-associated signaling pathways, specifically via NRF2, HIF-1, and Nf-κB pathways, may bridge mutual impact between COVID-19 and lung cancer. As expected, typical ROS-associated inflammation pathways (HIF-1 and Nf-κB) are activated in both diseases. The activation of both pathways in immune cells leads to an overloading immune response and exacerbates inflammation in COVID-19. In lung cancer, HIF-1 activation facilitates immune escape, while Nf-κB activation in T cells suppresses tumor growth. However, the altered NRF2 pathway show opposite trends between them, NRF2 pathways exert immunosuppressive effects in both diseases, as it represses the immune response in COVID-19 patients while facilitates the immune escape of tumor cells. Furthermore, we summarized the therapeutic targets (e.g., phytochemicals) on these ROS pathways. In sum, our review focus on the understanding of ROS Signaling in COVID-19 and lung cancer, showing that modulating ROS signaling pathways may alleviate the potentially mutual impacts between COVID-19 and lung cancer patients.

Diabetic Retinopathy and NADPH Oxidase-2: A Sweet Slippery Road

Diabetic retinopathy remains the leading cause of vision loss in working-age adults. The multi-factorial nature of the disease, along with the complex structure of the retina, have hindered in elucidating the exact molecular mechanism(s) of this blinding disease. Oxidative stress appears to play a significant role in its development and experimental models have shown that an increase in cytosolic Reacttive Oxygen Speies (ROS) due to the activation of NADPH oxidase 2 (Nox2), is an early event, which damages the mitochondria, accelerating loss of capillary cells. One of the integral proteins in the assembly of Nox2 holoenzyme, Rac1, is also activated in diabetes, and due to epigenetic modifications its gene transcripts are upregulated. Moreover, addition of hyperlipidemia in a hyperglycemic milieu (type 2 diabetes) further exacerbates Rac1-Nox2-ROS activation, and with time, this accelerates and worsens the mitochondrial damage, ultimately leading to the accelerated capillary cell loss and the development of diabetic retinopathy. Nox2, a multicomponent enzyme, is a good candidate to target for therapeutic interventions, and the inhibitors of Nox2 and Rac1 (and its regulators) are in experimental or clinical trials for other diseases; their possible use to prevent/halt retinopathy will be a welcoming sign for diabetic patients.

Clinicopathological and prognostic value of NADPH oxidase 2 (NOX2) in primary osteosarcoma

BACKGROUND

Osteosarcoma is the most common primary malignant bone tumor, particularly among children and adolescents, and the prognosis of osteosarcoma patients remains poor. The NADPH oxidase 2 (NOX2) has been found over-expressed in several human cancers, and closely associated with poor prognosis. Meanwhile the role of NOX2 in osteosarcoma patients has not been reported. This study aimed to investigate the clinicopathological and prognostic significance of NOX2 in osteosarcoma patients.

METHODS

Immunohistochemistry (IHC), western blot (WB) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to detect the expression of NOX2 in 55 primary osteosarcoma specimens and in 20 non-neoplastic bone tissue specimens. The correlations between NOX2 expression and clinicopathological parameters were analysed by using the χ2 test or Fisher's exact test. Disease free survival and overall survival of osteosarcoma patients were assessed by using the Kaplan-Meier method and Cox proportional hazards model.

RESULTS

NOX2 was over-expressed significantly in osteosarcoma compared with that in non-neoplastic bone tissue, and correlated with progression free survival (P < 0.001) and overall survival (P < 0.001). The over-expression of NOX2 was associated with tumor size (P < 0.001), tumor location (P < 0.001). The Cox analysed shown that the over-expression of NOX2 was predicted to be worse PFS (hazard ratio (HR) = 4.10, P = 0.004) and OS (hazard ratio (HR) = 3.50, P = 0.010) time in osteosarcoma patients.

CONCLUSIONS

The results of our study suggest that the over-expression of NOX2 is related to adverse clinical outcome, and can be viewed as an independent prognostic marker in osteosarcoma. Further research is required to verify the predictive value of NOX2 in osteosarcoma patients.

Targeting Evolutionary Conserved Oxidative Stress and Immunometabolic Pathways for the Treatment of Respiratory Infectious Diseases

Significance: Up until recently, metabolism has scarcely been referenced in terms of immunology. However, emerging evidence has shown that immune cells undergo an adaptation of metabolic processes, known as the metabolic switch. This switch is key to the activation, and sustained inflammatory phenotype in immune cells, which includes the production of cytokines and reactive oxygen species (ROS) that underpin infectious diseases, respiratory and cardiovascular disease, neurodegenerative disease, as well as cancer. Recent Advances: There is a burgeoning body of evidence that immunometabolism and redox biology drive infectious diseases. For example, influenza A virus (IAV) utilizes endogenous ROS production via NADPH oxidase (NOX)2-containing NOXs and mitochondria to circumvent antiviral responses. These evolutionary conserved processes are promoted by glycolysis, the pentose phosphate pathway, and the tricarboxylic acid (TCA) cycle that drive inflammation. Such metabolic products involve succinate, which stimulates inflammation through ROS-dependent stabilization of hypoxia-inducible factor-1α, promoting interleukin-1β production by the inflammasome. In addition, itaconate has recently gained significant attention for its role as an anti-inflammatory and antioxidant metabolite of the TCA cycle. Critical Issues: The molecular mechanisms by which immunometabolism and ROS promote viral and bacterial pathology are largely unknown. This review will provide an overview of the current paradigms with an emphasis on the roles of immunometabolism and ROS in the context of IAV infection and secondary complications due to bacterial infection such as Streptococcus pneumoniae. Future Directions: Molecular targets based on metabolic cell processes and ROS generation may provide novel and effective therapeutic strategies for IAV and associated bacterial superinfections.

Targeting an Autocrine Regulatory Loop in Cancer Stem-like Cells Impairs the Progression and Chemotherapy Resistance of Bladder Cancer

PURPOSE

Cancer stem-like cells (CSCs) contribute to bladder cancer chemotherapy resistance and progression, but the associated mechanisms have not been elucidated. This study determined whether blocking an autocrine signaling loop in CSCs improves the therapeutic effects of cis-platinum on bladder cancer.

EXPERIMENTAL DESIGN

The expression of the epithelial marker OV6 and other markers in human bladder cancer specimens was examined by IHC. The CSC properties of magnetic-activated cell sorting (MACS)-isolated OV6⁺ and OV6^- bladder cancer cells were examined. Molecular mechanisms were assessed through RNA-Seq, cytokine antibody arrays, co-immunoprecipitation (co-IP), chromatin immunoprecipitation (ChIP) and other assays. An orthotopic bladder cancer mouse model was established to evaluate the in vivo effects of a YAP inhibitor (verteporfin) and a PDGFR inhibitor (CP-673451) on the cis-platinum resistance of OV6⁺ CSCs in bladder cancer.

RESULTS

Upregulated OV6 expression positively associated with disease progression and poor prognosis for bladder cancer patients. Compared with OV6^- cells, OV6⁺ bladder cancer cells exhibited strong CSC characteristics, including self-renewal, tumor initiation in NOD/SCID mice, and chemotherapy resistance. YAP, which maintains the stemness of OV6⁺ CSCs, triggered PDGFB transcription by recruiting TEAD1. Autocrine PDGF-BB signaling through its receptor PDGFR stabilized YAP and facilitated YAP nuclear translocation. Furthermore, blocking the YAP/TEAD1/PDGF-BB/PDGFR loop with verteporfin or CP-673451 inhibited the cis-platinum resistance of OV6⁺ bladder cancer CSCs in an orthotopic bladder cancer model.

CONCLUSIONS

OV6 could be a helpful indicator of disease progression and prognosis for patients with bladder cancer, and targeting the autocrine YAP/TEAD1/PDGF-BB/PDGFR loop might serve as a remedy for cis-platinum resistance in patients with advanced bladder cancer.