Multiphoton Phosphorescence Quenching Microscopy Reveals Kinetics of Tumor Oxygenation during Antiangiogenesis and Angiotensin Signaling Inhibition.

PURPOSE: The abnormal function of tumor blood vessels causes tissue hypoxia, promoting disease progression and treatment resistance. Although tumor microenvironment normalization strategies can alleviate hypoxia globally, how local oxygen levels change is not known because of the inability to longitudinally assess vascular and interstitial oxygen in tumors with sufficient resolution. Understanding the spatial and temporal heterogeneity should help improve the outcome of various normalization strategies. EXPERIMENTAL DESIGN: We developed a multiphoton phosphorescence quenching microscopy system using a low-molecular-weight palladium porphyrin probe to measure perfused vessels, oxygen tension, and their spatial correlations in vivo in mouse skin, bone marrow, and four different tumor models. Further, we measured the temporal and spatial changes in oxygen and vessel perfusion in tumors in response to an anti-VEGFR2 antibody (DC101) and an angiotensin-receptor blocker (losartan). RESULTS: We found that vessel function was highly dependent on tumor type. Although some tumors had vessels with greater oxygen-carrying ability than those of normal skin, most tumors had inefficient vessels. Further, intervessel heterogeneity in tumors is associated with heterogeneous response to DC101 and losartan. Using both vascular and stromal normalizing agents, we show that spatial heterogeneity in oxygen levels persists, even with reductions in mean extravascular hypoxia. CONCLUSIONS: High-resolution spatial and temporal responses of tumor vessels to two agents known to improve vascular perfusion globally reveal spatially heterogeneous changes in vessel structure and function. These dynamic vascular changes should be considered in optimizing the dose and schedule of vascular and stromal normalizing strategies to improve the therapeutic outcome.

Actinomycetes Enrich Soil Rhizosphere and Improve Seed Quality as well as Productivity of Legumes by Boosting Nitrogen Availability and Metabolism.

The use of actinomycetes for improving soil fertility and plant production is an attractive strategy for developing sustainable agricultural systems due to their effectiveness, eco-friendliness, and low production cost. Out of 17 species isolated from the soil rhizosphere of legume crops, 4 bioactive isolates were selected and their impact on 5 legumes: soybean, kidney bean, chickpea, lentil, and pea were evaluated. According to the morphological and molecular identification, these isolates belong to the genus Streptomyces. Here, we showed that these isolates increased soil nutrients and organic matter content and improved soil microbial populations. At the plant level, soil enrichment with actinomycetes increased photosynthetic reactions and eventually increased legume yield. Actinomycetes also increased nitrogen availability in soil and legume tissue and seeds, which induced the activity of key nitrogen metabolizing enzymes, e.g., glutamine synthetase, glutamate synthase, and nitrate reductase. In addition to increased nitrogen-containing amino acids levels, we also report high sugar, organic acids, and fatty acids as well as antioxidant phenolics, mineral, and vitamins levels in actinomycete treated legume seeds, which in turn improved their seed quality. Overall, this study shed the light on the impact of actinomycetes on enhancing the quality and productivity of legume crops by boosting the bioactive primary and secondary metabolites. Moreover, our findings emphasize the positive role of actinomycetes in improving the soil by enriching its microbial population. Therefore, our data reinforce the usage of actinomycetes as biofertilizers to provide sustainable food production and achieve biosafety.

Salinity Stress Enhances the Antioxidant Capacity of Bacillus and Planococcus Species Isolated From Saline Lake Environment.

This study aims at exploiting salinity stress as an innovative, simple, and cheap method to enhance the production of antioxidant metabolites and enzymes from bacteria for potential application as functional additives to foods and pharmaceuticals. We investigated the physiological and biochemical responses of four bacterial isolates, which exhibited high tolerance to 20% NaCl (wt/vol), out of 27 bacterial strains isolated from Aushazia Lake, Qassim region, Saudi Arabia. The phylogenetic analysis of the 16S rRNA genes of these four isolates indicated that strains ST1 and ST2 belong to genus Bacillus, whereas strains ST3 and ST4 belong to genus Planococcus. Salinity stress differentially induced oxidative damage, where strains ST3 and ST4 showed increased lipid peroxidation, lipoxygenase, and xanthine oxidase levels. Consequently, high antioxidant contents were produced to control oxidative stress, particularly in ST3 and ST4. These two Planococcus strains showed increased glutathione cycle, phenols, flavonoids, antioxidant capacity, catalase, and/or superoxide dismutase (SOD). Interestingly, the production of glutathione by Planococcus strains was some thousand folds greater than by higher plants. On the other hand, the induction of antioxidants in ST1 and ST2 was restricted to phenols, flavonoids, peroxidase, glutaredoxin, and/or SOD. The hierarchical analysis also supported strain-specific responses. This is the first report that exploited salinity stress for promoting the production of antioxidants from bacterial isolates, which can be utilized as postbiotics for promising applications in foods and pharmaceuticals.

Heat stress as an innovative approach to enhance the antioxidant production in Pseudooceanicola and Bacillus isolates.

It is well known that the quality and quantity of bioactive metabolites in plants and microorganisms are affected by environmental factors. We applied heat stress as a promising approach to stimulate the production of antioxidants in four heat-tolerant bacterial strains (HT1 to HT4) isolated from Aushazia Lake, Qassim Region, Saudi Arabia. The phylogenetic analysis of the 16S rRNA sequences indicated that HT1, HT3 and HT4 belong to genus Bacillus. While HT2 is closely related to Pseudooceanicola marinus with 96.78% similarity. Heat stress differentially induced oxidative damage i.e., high lipid peroxidation, lipoxygenase and xanthine oxidase levels in HT strains. Subsequently, heat stress induced the levels of flavonoids and polyphenols in all strains and glutathione (GSH) in HT2. Heat stress also improved the antioxidant enzyme activities, namely, CAT, SOD and POX in all strains and thioredoxin activity in HT3 and HT4. While GSH cycle (GSH level and GPX, GR, Grx and GST activities) was only detectable and enhanced by heat stress in HT2. The hierarchical cluster analysis of the antioxidants also supported the strain-specific responses. In conclusion, heat stress is a promising approach to enhance antioxidant production in bacteria with potential applications in food quality improvement and health promotion.

Angiotensin inhibition enhances drug delivery and potentiates chemotherapy by decompressing tumour blood vessels.

Cancer and stromal cells actively exert physical forces (solid stress) to compress tumour blood vessels, thus reducing vascular perfusion. Tumour interstitial matrix also contributes to solid stress, with hyaluronan implicated as the primary matrix molecule responsible for vessel compression because of its swelling behaviour. Here we show, unexpectedly, that hyaluronan compresses vessels only in collagen-rich tumours, suggesting that collagen and hyaluronan together are critical targets for decompressing tumour vessels. We demonstrate that the angiotensin inhibitor losartan reduces stromal collagen and hyaluronan production, associated with decreased expression of profibrotic signals TGF-ß1, CCN2 and ET-1, downstream of angiotensin-II-receptor-1 inhibition. Consequently, losartan reduces solid stress in tumours resulting in increased vascular perfusion. Through this physical mechanism, losartan improves drug and oxygen delivery to tumours, thereby potentiating chemotherapy and reducing hypoxia in breast and pancreatic cancer models. Thus, angiotensin inhibitors -inexpensive drugs with decades of safe use - could be rapidly repurposed as cancer therapeutics.

Anti-angiogenesis efficacy of the garlic ingredient alliin and antioxidants: role of nitric oxide and p53.

Alliin, a compound derived from garlic, demonstrated dose-dependent inhibition of fibroblast growth factor-2 (FGF2)-induced human endothelial cell (EC) tube formation and angiogenesis in the chick chorioallantoic membrane (CAM) model. Additionally, alliin demonstrated potent inhibition of vascular endothelial growth factor (VEGF)-induced angiogenesis in the CAM model. The antioxidant vitamins C and E significantly (P < 0.001) enhanced the inhibitory efficacy of alliin on FGF2-induced EC tube formation and angiogenesis. Alliin significantly increased (P < 0.01) nitric oxide (NO) release into the CAM fluid, which was further enhanced by vitamins C and E. The NO synthesis inhibitor nitro-L-arginine methyl ester (L-NAME) reversed the anti-angiogenesis efficacy of alliin in the CAM model. Vitamins C and E significantly enhanced the anticancer efficacy of alliin in inhibiting colon and fibrosarcoma tumor growth. Alliin significantly inhibited both FGF2 and VEGF secretion from human fibrosarcoma cells in a concentration-dependent manner. Additionally, alliin up-regulated the p53 production in FGF2-stimulated EC. These data indicated a synergistic effect of antioxidants on the anti-angiogenesis and anticancer efficacy of alliin. These data also suggest the implication of cellular NO and p53 as mediators of anti-angiogenesis and anticancer effects of alliin.

Angiogenesis inhibitors: current & future directions.

The field of angiogenesis modulation is at a major crossroad. A tremendous advancement in basic science in this field is providing an excellent support for the concept, which is in contrast to a lack of strong clinical support to date. With regard to the large gap between experimental data and clinical data, the best model of human malignancy is in human cancer patients and the best model of human ocular angiogenesis-mediated disorders such as diabetic retinopathy (DR) and age related macular degeneration (AMD) is in human RD and AMD patients. Additionally, clinical outcomes should include benefit/risk ratios, hard end points (mortality and quality of life as opposed to increased microvascular density with pro-angiogenic agents or tumor size reduction with anti-angiogenesis agents) as well as cost effectiveness. Experimental models should be used to provide guidance, placebo effect, comparative data, and mechanistic understanding as opposed to being used for expected clinical efficacy. We also have to understand existing strategies and how angiogenesis modulation can add further value (i.e. not to replace existing strategy but rather improve efficacy/safety). Recent investigation defined numerous strategies in the modulation of angiogenesis. Those strategies are driven from haemostatic, fibrinolytic, cell adhesion molecules, extracellular matrix, growth factors, and other endogenous systems involved in the modulation of angiogenesis.

Nocardiopsis alkaliphila sp. nov., a novel alkaliphilic actinomycete isolated from desert soil in Egypt.

An alkaliphilic actinomycete strain, designated YIM 80379T, was isolated from a soil sample collected from the eastern desert of Egypt and subjected to polyphasic taxonomy. The strain produced substrate and aerial mycelia on different media, with an optimum pH for growth of 9.5-10 and scarce or no growth at pH 7. Strain YIM 80379T contained meso-diaminopimelic acid, no diagnostic sugars, type PIII phospholipids and MK-10(H6) and MK-10(H8) as the predominant menaquinones. All of these characters assign isolate YIM 80379T consistently to the genus Nocardiopsis. This was confirmed by 16S rDNA analysis. It can be differentiated from all Nocardiopsis species with validly published names by phenotypic characteristics, phylogenetic analysis and DNA-DNA hybridization results. On the basis of polyphasic evidence, a novel species, Nocardiopsis alkaliphila sp. nov., is proposed. The type strain of the species is YIM 80379T (=CCTCC AA001031T=DSM 44657T).