Tumor microenvironment-modulated nanoparticles with cascade energy transfer as internal light sources for photodynamic therapy of deep-seated tumors.

Photodynamic therapy (PDT) is an appealing modality for cancer treatments. However, the limited tissue penetration depth of external-excitation light makes PDT impossible in treating deep-seated tumors. Meanwhile, tumor hypoxia and intracellular reductive microenvironment restrain the generation of reactive oxygen species (ROS). To overcome these limitations, a tumor-targeted self-illuminating supramolecular nanoparticle T-NPCe6-L-N is proposed by integrating photosensitizer Ce6 with luminol and nitric oxide (NO) for chemiluminescence resonance energy transfer (CRET)-activated PDT. The high H2O2 level in tumor can trigger chemiluminescence of luminol to realize CRET-activated PDT without exposure of external light. Meanwhile, the released NO significantly relieves tumor hypoxia via vascular normalization and reduces intracellular reductive GSH level, further enhancing ROS abundance. Importantly, due to the different ROS levels between cancer cells and normal cells, T-NPCe6-L-N can selectively trigger PDT in cancer cells while sparing normal cells, which ensured low side effect. The combination of CRET-based photosensitizer-activation and tumor microenvironment modulation overcomes the innate challenges of conventional PDT, demonstrating efficient inhibition of orthotopic and metastatic tumors on mice. It also provoked potent immunogenic cell death to ensure long-term suppression effects. The proof-of-concept research proved as a new strategy to solve the dilemma of PDT in treatment of deep-seated tumors.

Evidence to support cultivated fruiting body of Ophiocordyceps sinensis (Ascomycota)'s role in relaxing airway smooth muscle.

ETHNOPHARMACOLOGICAL RELEVANCE: Ophiocordyceps sinensis (O. sinensis) is a genus of Ascomycete fungus that is endemic to the alpine meadows of the Tibetan Plateau and adjoining Himalayas. It has been used traditionally as a tonic to improve respiratory health in ancient China as well as to promote vitality and longevity. Bioactive components found in O. sinensis such as adenosine, cordycepin, 3-deoxyadenosine, L-arginine and polysaccharides have gained increasing interest in recent years due to their antioxidative and other properties, which include anti-asthmatic, antiviral, immunomodulation and improvement of general health. AIM OF THE STUDY: This study's primary aim was to investigate the effect of a cultivated fruiting body of O. sinensis strain (OCS02®) on airways patency and the secondary focus was to investigate its effect on the lifespan of Caenorhabditis elegans. MATERIALS AND METHODS: A cultivated strain, OCS02®, was employed and the metabolic profile of its cold-water extract (CWE) was analysed through liquid chromatography-mass spectrometry (LC-MS). Organ bath approach was used to investigate the pharmacological properties of OCS02® CWE when applied on airway tissues obtained from adult male Sprague-Dawley rats. The airway relaxation mechanisms of OCS02® CWE were explored using pharmacological tools, where the key regulators in airway relaxation and constriction were investigated. For the longevity study, age-synchronised, pos-1 RNAi-treated wild-type type Caenorhabditis elegans at the L4 stage were utilised for a lifespan assay. RESULTS: Various glycopeptides and amino acids, particularly a high concentration of L-arginine, were identified from the LC-MS analysis. In airway tissues, OCS02® CWE induced a significantly greater concentration-dependent relaxation when compared to salbutamol. The relaxation response was significantly attenuated in the presence of NG-Nitro-L-arginine methyl ester (L-NAME), 1H-[1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one (ODQ) and several K+ channel blockers. The longevity effect induced by OCS02® CWE (5 mg/mL and above) was observed in C. elegans by at least 17%. CONCLUSIONS: These findings suggest that the airway relaxation mechanisms of OCS02® CWE involved cGMP-dependent and cGMP-independent nitric oxide signalling pathways. This study provides evidence that the cultivated strain of OCS02® exhibits airway relaxation effects which supports the traditional use of its wild O. sinensis in strengthening respiratory health.

Neuropilin-2 expressing cells in breast cancer are S-nitrosylation hubs that mitigate radiation-induced oxidative stress.

The high rate of recurrence after radiation therapy in triple-negative breast cancer (TNBC) indicates that novel approaches and targets are needed to enhance radiosensitivity. Here, we report that neuropilin-2 (NRP2), a receptor for vascular endothelial growth factor (VEGF) that is enriched on sub-populations of TNBC cells with stem cell properties, is an effective therapeutic target for sensitizing TNBC to radiotherapy. Specifically, VEGF/NRP2 signaling induces nitric oxide synthase 2 (NOS2) transcription by a mechanism dependent on Gli1. NRP2-expressing tumor cells serve as a hub to produce nitric oxide (NO), an autocrine and paracrine signaling metabolite, which promotes cysteine-nitrosylation of Kelch-like ECH-asssociated protein 1 (KEAP1) and, consequently, nuclear factor erythroid 2-related factor 2 (NFE2L2)-mediated transcription of antioxidant response genes. Inhibiting VEGF binding to NRP2, using a humanized monoclonal antibody (mAb), results in NFE2L2 degradation via KEAP1 rendering cell lines and organoids vulnerable to irradiation. Importantly, treatment of patient-derived xenografts with the NRP2 mAb and radiation resulted in significant tumor necrosis and regression compared to radiation alone. Together, these findings reveal a targetable mechanism of radioresistance and they support the use of NRP2 mAb as an effective radiosensitizer in TNBC.

Experimental Insights into the Formation, Reactivity, and Crosstalk of Thionitrite (SNO-) and Perthionitrite (SSNO-).

Hydrogen sulfide (H2S) and nitric oxide (NO) are important gaseous biological signaling molecules that are involved in complex cellular pathways. A number of physiological processes require both H2S and NO, which has led to the proposal that different H2S/NO• crosstalk species, including thionitrite (SNO-) and perthionitrite (SSNO-), are responsible for this observed codependence. Despite the importance of these S/N hybrid species, the reported properties and characterization, as well as the fundamental pathways of formation and subsequent reactivity, remain poorly understood. Herein we report new experimental insights into the fundamental reaction chemistry of pathways to form SNO- and SSNO-, including mechanisms for proton-mediated interconversion. In addition, we demonstrate new modes of reactivity with other sulfur-containing potential crosstalk species, including carbonyl sulfide (COS).

Tuning the Reactivity of Copper(II)-Nitrite Core Towards Nitric Oxide Generation.

Insights into the molecular mechanism and factors affecting nitrite-to-NO transformation at transition metal sites are essential for developing sustainable technologies relevant to NO-based therapeutics, waste water treatment, and agriculture. A set of copper(II)-nitrite complexes 1-4 have been isolated employing tridentate pincer-type ligands (quL, pyL, ClArOL-, PhOL-) featuring systematically varied donors. Although the X-ray crystal structures of the copper(II)-nitrite cores in 1-4 are comparable, electrochemical studies on complexes 1-4 reveal that redox properties of these complexes differ due to the changes in the s-donor abilities of the phenolate / N-heterocycle based donor sites. Reactivity of these nitrite complexes with oxygen-atom-transfer (OAT) reagent (e.g. triphenyl phosphine Ph3P) and H+/e- donor reagent (e.g. substituted phenols ArOH) show the reduction of nitrite to NO gas. Detailed kinetic investigations including kinetic isotope effect (KIE), Eyring analyses for determining the activation parameters unfold that reduction of nitrite at copper(II) by Ph3P or ArOH are influenced by the CuII/CuI redox potential. Finally, this study allows mechanism driven development of catalytic nitrite reduction by ArOH in the presence of 10 mol% copper complex (1).

Nitric Oxide-Releasing Topical Treatments for Cutaneous Melanoma.

Melanoma is an aggressive skin cancer notorious for high levels of drug resistance. Additionally, current treatments such as immunotherapies are often associated with numerous adverse side effects. The use of nitric oxide (NO) may represent an attractive treatment for melanoma due to NO's various anticancer properties, unlikeliness to foster resistance, and limited toxicity toward healthy tissues. The anticancer effects of chemical NO donors have been explored previously but with limited understanding of the needed characteristics for exerting optimal antimelanoma activity. Herein, the in vitro therapeutic efficacy of three macromolecular NO donor systems (i.e., cyclodextrin, mesoporous silica nanoparticles, and hyaluronic acid) with tunable NO-release kinetics was explored by evaluating skin permeation along with toxicity against melanoma and healthy skin cells. Cytotoxicity against melanoma cells was dependent on NO payload and not donor identity or NO-release kinetics. In contrast, cytotoxicity against healthy cells was primarily influenced by the macromolecular NO donor, with cyclodextrin- and hyaluronic acid-based NO donors having the highest therapeutic indices. In vitro skin permeation was influenced by both the size and charge of the NO donor, with smaller, more neutral donors resulting in greater permeation. A Pluronic F127 organogel was optimized for the delivery of a cyclodextrin-based NO donor. Delivery of the NO donor in this manner resulted in increased in vitro skin permeation and reduced tumor growth in an in vivo model.

Novel Quinoline Nitrate Derivatives: Synthesis, Characterization, and Evaluation of their Anticancer Activity with a Focus on Molecular Docking and NO Release.

BACKGROUND: Nitric Oxide (NO) has recently gained recognition as a promising approach in the field of cancer therapy. The quinoline scaffold is pivotal in cancer drug research and is known for its versatility and diverse mechanisms of action. OBJECTIVE: This study presents the synthesis, characterization, and evaluation of novel quinoline nitrate derivatives as potential anticancer agents. METHODS: The compounds were synthesized through a multi-step process involving the preparation of substituted 1-(2-aminophenyl) ethan-1-one, followed by the synthesis of substituted 2- (chloromethyl)-3,4-dimethylquinolines, and finally, the formation of substituted (3,4- dimethylquinolin-2-yl) methyl nitrate derivatives. The synthesized compounds were characterized using various spectroscopic techniques. Molecular docking studies were conducted to assess the binding affinity of the compounds to the EGFR tyrosine kinase domain. RESULTS: The docking scores revealed varying degrees of binding affinity, with compound 6k exhibiting the highest score. The results suggested a correlation between molecular docking scores and anticancer activity. Further evaluations included MTT assays to determine the cytotoxicity of the compounds against Non-Small Cell Lung Cancer (A-549) and pancreatic cancer (PANC-1) cell lines. Compounds with electron-donating groups displayed notable anticancer potential, and there was a correlation between NO release and anticancer activity. The study also investigated nitric oxide release from the compounds, revealing compound 6g as the highest NO releaser. CONCLUSION: The synthesized quinoline nitrate derivatives showed promising anticancer activity, with compound 6g standing out as a potential lead compound. The correlation between molecular docking, NO release, and anticancer activity suggests the importance of specific structural features in the design of effective anticancer agents.

Comparison of Biomarkers of Oxidative Stress, Inflammation, and Endothelial Function Among Vegetarians and Non-vegetarians of Vijayapura, India: A Pilot Study.

BACKGROUND: The known impact of diet on the pathophysiology of various chronic diseases and the current dietary transition in the country make it essential to assess the influence of dietary patterns specific to this region on inflammation, oxidative stress, and endothelial functions. OBJECTIVE: This study compared oxidative stress, inflammation, and endothelial functions among vegetarians and non-vegetarians in Vijayapura, Karnataka, India. METHODS: The present cross-sectional comparative study involved apparently healthy vegetarians (n=35) and non-vegetarians (n=35) aged 20-40. The anthropometric measurements like height (cm) and weight (kg) were recorded, and the BMI was calculated. The physiological parameters like systolic and diastolic blood pressure and pulse rate were recorded. Serum high-sensitivity C-reactive protein (hs-CRP), serum malondialdehyde (MDA), and serum nitric oxide (NO) were estimated as markers of inflammation, oxidative stress, and endothelial function, respectively. Statistical analysis was done using SPSS Statistics version 20.0 (IBM Corp. Released 2011. IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp.). RESULTS: The average age of vegetarians and non-vegetarians was 25.22 ± 7.63 years and 25.60 ± 5.64 years, respectively. Anthropometric and physiological parameters were comparable between the two groups. However, there was a trend for higher mean body weight among non-vegetarians (53.94± 6.73 vs. 57.22±7.18) with a marginal non-statistically significant p-value (p=0.052). Vegetarians showed significantly higher serum MDA levels than non-vegetarians (2.14 (0.93-2.91) vs. 0.64 (0.35-1.32); p=0.000), while hs-CRP (vegetarians - 0.01 (0.005-0.034) vs. non-vegetarians - 0.03 (0.01-0.04); p=0.18) and serum NO levels (vegetarians - 6.72 (5.46-8.39) vs. non-vegetarians - 5.43 (2.87-9.16); p=0.215) were similar in both groups. CONCLUSION: The results were intriguing and contrasting, as serum MDA is remarkably higher among vegetarians than non-vegetarians, pointing toward greater oxidative stress among the former and possibly indicating a dietary imbalance among vegetarians, which needs further exploration.

Raloxifene Prevents Chemically-Induced Ferroptotic Neuronal Death In Vitro and In Vivo.

Ferroptosis, a regulated form of cell death characterized by excessive iron-dependent lipid peroxidation, can be readily induced in cultured cells by chemicals such as erastin and RSL3. Protein disulfide isomerase (PDI) has been identified as an upstream mediator of chemically induced ferroptosis and also a target for ferroptosis protection. In this study, we discovered that raloxifene (RAL), a selective estrogen receptor modulator known for its neuroprotective actions in humans, can effectively inhibit PDI function and provide robust protection against chemically induced ferroptosis in cultured HT22 neuronal cells. Specifically, RAL can bind directly to PDI both in vitro and in intact neuronal cells and inhibit its catalytic activity. Computational modeling analysis reveals that RAL can tightly bind to PDI through forming a hydrogen bond with its His256 residue, and biochemical analysis further shows that when PDI's His256 is mutated to Ala256, RAL loses its inhibition of PDI's catalytic activity. This inhibition of PDI by RAL significantly reduces the dimerization of both the inducible and neuronal nitric oxide synthases and the accumulation of nitric oxide, both of which have recently been shown to play a crucial role in mediating chemically induced ferroptosis through subsequent induction of ROS and lipid-ROS accumulation. In vivo behavioral analysis shows that mice treated with RAL are strongly protected against kainic acid-induced memory deficits and hippocampal neuronal damage. In conclusion, this study demonstrates that RAL is a potent inhibitor of PDI and can effectively prevent chemically induced ferroptosis in hippocampal neurons both in vitro and in vivo. These findings offer a novel estrogen receptor-independent mechanism for RAL's neuroprotective actions in animal models and humans.

Nitrogen oxides emissions from coastal wetland sediments: Experimental assessment of the influence of vegetation and nitrogen input.

Nitrogen oxides (NOx = NO + NO2) have essential impacts on global climate and the environment, making it essential to study the contribution of wetland-generated NOx to environmental problems. With exogenous nitrogen input from anthropogenic activities, wetland sediments become active emission hotspots for NOx. In this study, we conducted field experiments in a typical salt marsh wetland to measure nitric oxide (NO, the primary component of NOx from sediments) exchange fluxes in both mudflat and vegetated sediments. We found that NO fluxes in vegetated sediments (0.40 ±â€¯0.15 × 10-12 kg N m-2 s-1) were relatively higher than in mudflat sediments (-1.31 ±â€¯1.39 × 10-12 kg N m-2 s-1), with this difference occurring only during the vegetation-dying season (autumn). Correlations between sediment NO fluxes and environmental parameters revealed that NO flux variation during the observation period was primarily influenced by sediment respiration, temperature, water content, and substrate availability. However, the influence of these factors on NO fluxes differed between mudflat and vegetated sediments. In-situ data analysis also suggested that tidal horizontal migration, which affects sediment substrate and salinity, may regulate sediment NO emissions. Furthermore, in-situ incubations with nitrogen addition (ammonia, nitrite, and nitrate) were conducted to study the response of sediment NO emissions to exogenous nitrogen. We observed that nitrogen addition caused a 259.7 % increase in NO emissions from vegetated sediments compared to the control during the effective period of nitrogen addition (days 1-3). However, although nitrogen addition markedly stimulated sediment NO emissions, the overall NO production capacity constrained the extent of this increase.