Sensitive determination of cell number using the CyQUANT cell proliferation assay

The effect of biocide chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT) mixture on C2C12 muscle cell damage attributed to mitochondrial reactive oxygen species overproduction and autophagy activation

The mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (CMIT/MIT) is a biocide widely used as a preservative in various commercial products. This biocide has also been used as an active ingredient in humidifier disinfectants in South Korea, resulting in serious health effects among users. Recent evidence suggests that the underlying mechanism of CMIT/MIT-initiated toxicity might be associated with defects in mitochondrial functions. The aim of this study was to utilize the C2C12 skeletal muscle model to investigate the effects of CMIT/MIT on mitochondrial function and relevant molecular pathways associated with skeletal muscle dysfunction. Data demonstrated that exposure to CMIT/MIT during myogenic differentiation induced significant mitochondrial excess production of reactive oxygen species (ROS) and a decrease in intracellular ATP levels. Notably, CMIT/MIT significantly inhibited mitochondrial oxidative phosphorylation (Oxphos) and reduced mitochondrial mass at a lower concentration than the biocide amount, which diminished the viability of myotubes. CMIT/MIT induced activation of autophagy flux and decreased protein expression levels of myosin heavy chain (MHC). Taken together, CMIT/MIT exposure produced damage in C2C12 myotubes by impairing mitochondrial bioenergetics and activating autophagy. Our findings contribute to an increased understanding of the underlying mechanisms associated with CMIT/MIT-induced adverse skeletal muscle health effects.

Guidance on biomaterials for periodontal tissue regeneration: Fabrication methods, materials and biological considerations

Regeneration of the multiple tissues and interfaces in the periodontal complex necessitates multidisciplinary evaluation to establish structure/function relationships. This article, an initiative of the Academy of Dental Materials, provides guidance for performing chemical, structural, and mechanical characterization of materials for periodontal tissue regeneration, and outlines important recommendations on methods of testing bioactivity, biocompatibility, and antimicrobial properties of biomaterials/scaffolds for periodontal tissue engineering. First, we briefly summarize periodontal tissue engineering fabrication methods. We then highlight critical variables to consider when evaluating a material for periodontal tissue regeneration, and the fundamental tests used to investigate them. The recommended tests and designs incorporate relevant international standards and provide a framework for characterizing newly developed materials focusing on the applicability of those tests for periodontal tissue regeneration. The most common methods of biofabrication (electrospinning, injectable hydrogels, fused deposition modelling, melt electrowriting, and bioprinting) and their specific applications in periodontal tissue engineering are reviewed. The critical techniques for morphological, chemical, and mechanical characterization of different classes of materials used in periodontal regeneration are then described. The major advantages and drawbacks of each assay, sample sizes, and guidelines on specimen preparation are also highlighted. From a biological standpoint, fundamental methods for testing bioactivity, the biocompatibility of materials, and the experimental models for testing the antimicrobial potential are included in this guidance. In conclusion, researchers performing studies on periodontal tissue regeneration will have this guidance as a tool to assess essential properties and characteristics of their materials/scaffold-based strategies.

AOP report: Development of an adverse outcome pathway for deposition of energy leading to cataracts

Cataracts are one of the leading causes of blindness, with an estimated 95 million people affected worldwide. A hallmark of cataract development is lens opacification, typically associated not only with aging but also radiation exposure as encountered by interventional radiologists and astronauts during the long-term space mission. To better understand radiation-induced cataracts, the adverse outcome pathway (AOP) framework was used to structure and evaluate knowledge across biological levels of organization (e.g., macromolecular, cell, tissue, organ, organism and population). AOPs identify a sequence of key events (KEs) causally connected by key event relationships (KERs) beginning with a molecular initiating event to an adverse outcome (AO) of relevance to regulatory decision-making. To construct the cataract AO and retrieve evidence to support it, a scoping review methodology was used to filter, screen, and review studies based on the modified Bradford Hill criteria. Eight KEs were identified that were moderately supported by empirical evidence (e.g., dose-, time-, incidence-concordance) across the adjacent (directly linked) relationships using well-established endpoints. Over half of the evidence to justify the KER linkages was derived from the evidence stream of biological plausibility. Early KEs of oxidative stress and protein modifications had strong linkages to downstream KEs and could be the focus of countermeasure development. Several identified knowledge gaps and inconsistencies related to the quantitative understanding of KERs which could be the basis of future research, most notably directed to experiments in the range of low or moderate doses and dose-rates, relevant to radiation workers and other occupational exposures.

Cytotoxicity of phosphoramidate, bis-amidate and cycloSal prodrug metabolites against tumour and normal cells

Phosphonate and phosphate prodrugs are integral to enhancing drug permeability, but the potential toxicity of their metabolites requires careful consideration. This study evaluates the impact of widely used phosphoramidate, bis-amidate, and cycloSal phosph(on)ate prodrug metabolites on BxPC3 pancreatic cancer cells, GL261-Luc glioblastoma cells, and primary cultured mouse astrocytes. 1-Naphthol and 2-naphthol demonstrated the greatest toxicity. Notably, 2-naphthol exhibited an ED50 of 21 μM on BxPC3 cells, surpassing 1-naphthol with an ED50 of 82 μM. Real-time xCELLigence experiments revealed notable activity for both metabolites at a low concentration of 16 μM. On primary cultured mouse astrocyte cells, all prodrugs exhibited reduced viability at 128 to 256 μM after only 4 hours of exposure. A cell-type-dependent sensitivity to phosph(on)ate prodrug metabolites was evident, with normal cells showing greater susceptibility than corresponding tumour cells. The results suggest it is essential to consider the potential cytotoxicity of phosph(on)ate prodrugs in the drug design and evaluation process.

A High-Throughput Screening of a Natural Products Library for Mitochondria Modulators

Mitochondria, the energy hubs of the cell, are progressively becoming attractive targets in the search for potent therapeutics against neurodegenerative diseases. The pivotal role of mitochondrial dysfunction in the pathogenesis of various diseases, including Parkinson's disease (PD), underscores the urgency of discovering novel therapeutic strategies. Given the limitations associated with available treatments for mitochondrial dysfunction-associated diseases, the search for new potent alternatives has become imperative. In this report, we embarked on an extensive screening of 4224 fractions from 384 Australian marine organisms and plant samples to identify natural products with protective effects on mitochondria. Our initial screening using PD patient-sourced olfactory neurosphere-derived (hONS) cells with rotenone as a mitochondria stressor resulted in 108 promising fractions from 11 different biota. To further assess the potency and efficacy of these hits, the 11 biotas were subjected to a subsequent round of screening on human neuroblastoma (SH-SY5Y) cells, using 6-hydroxydopamine to induce mitochondrial stress, complemented by a mitochondrial membrane potential assay. This rigorous process yielded 35 active fractions from eight biotas. Advanced analysis using an orbit trap mass spectrophotometer facilitated the identification of the molecular constituents of the most active fraction from each of the eight biotas. This meticulous approach led to the discovery of 57 unique compounds, among which 12 were previously recognized for their mitoprotective effects. Our findings highlight the vast potential of natural products derived from Australian marine organisms and plants in the quest for innovative treatments targeting mitochondrial dysfunction in neurodegenerative diseases.

Rational design of an artificial tethered enzyme for non-templated post-transcriptional mRNA polyadenylation by the second generation of the C3P3 system

We have previously introduced the first generation of C3P3, an artificial system that allows the autonomous in-vivo production of mRNA with m7GpppN-cap. While C3P3-G1 synthesized much larger amounts of capped mRNA in human cells than conventional nuclear expression systems, it produced a proportionately much smaller amount of the corresponding proteins, indicating a clear defect of mRNA translatability. A possible mechanism for this poor translatability could be the rudimentary polyadenylation of the mRNA produced by the C3P3-G1 system. We therefore sought to develop the C3P3-G2 system using an artificial enzyme to post-transcriptionally lengthen the poly(A) tail. This system is based on the mutant mouse poly(A) polymerase alpha fused at its N terminus with an N peptide from the λ virus, which binds to BoxBr sequences placed in the 3'UTR region of the mRNA of interest. The resulting system selectively brings mPAPαm7 to the target mRNA to elongate its poly(A)-tail to a length of few hundred adenosine. Such elongation of the poly(A) tail leads to an increase in protein expression levels of about 2.5-3 times in cultured human cells compared to the C3P3-G1 system. Finally, the coding sequence of the tethered mutant poly(A) polymerase can be efficiently fused to that of the C3P3-G1 enzyme via an F2A sequence, thus constituting the single-ORF C3P3-G2 enzyme. These technical developments constitute an important milestone in improving the performance of the C3P3 system, paving the way for its applications in bioproduction and non-viral human gene therapy.

Organoids as a biomarker for personalized treatment in metastatic colorectal cancer: drug screen optimization and correlation with patient response

BACKGROUND

The inability to predict treatment response of colorectal cancer patients results in unnecessary toxicity, decreased efficacy and survival. Response testing on patient-derived organoids (PDOs) is a promising biomarker for treatment efficacy. The aim of this study is to optimize PDO drug screening methods for correlation with patient response and explore the potential to predict responses to standard chemotherapies.

METHODS

We optimized drug screen methods on 5-11 PDOs per condition of the complete set of 23 PDOs from patients treated for metastatic colorectal cancer (mCRC). PDOs were exposed to 5-fluorouracil (5-FU), irinotecan- and oxaliplatin-based chemotherapy. We compared medium with and without N-acetylcysteine (NAC), different readouts and different combination treatment set-ups to capture the strongest association with patient response. We expanded the screens using the optimized methods for all PDOs. Organoid sensitivity was correlated to the patient's response, determined by % change in the size of target lesions. We assessed organoid sensitivity in relation to prior exposure to chemotherapy, mutational status and sidedness.

RESULTS

Drug screen optimization involved excluding N-acetylcysteine from the medium and biphasic curve fitting for 5-FU & oxaliplatin combination screens. CellTiter-Glo measurements were comparable with CyQUANT and did not affect the correlation with patient response. Furthermore, the correlation improved with application of growth rate metrics, when 5-FU & oxaliplatin was screened in a ratio, and 5-FU & SN-38 using a fixed dose of SN-38. Area under the curve was the most robust drug response curve metric. After optimization, organoid and patient response showed a correlation coefficient of 0.58 for 5-FU (n = 6, 95% CI -0.44,0.95), 0.61 for irinotecan- (n = 10, 95% CI -0.03,0.90) and 0.60 for oxaliplatin-based chemotherapy (n = 11, 95% CI -0.01,0.88). Median progression-free survival of patients with resistant PDOs to oxaliplatin-based chemotherapy was significantly shorter than sensitive PDOs (3.3 vs 10.9 months, p = 0.007). Increased resistance to 5-FU in patients with prior exposure to 5-FU/capecitabine was adequately reflected in PDOs (p = 0.003).

CONCLUSIONS

Our study emphasizes the critical impact of the screening methods for determining correlation between PDO drug screens and mCRC patient outcomes. Our 5-step optimization strategy provides a basis for future research on the clinical utility of PDO screens.

Triphasic 3D In Vitro Model of Bone-Tendon-Muscle Interfaces to Study Their Regeneration

The transition areas between different tissues, known as tissue interfaces, have limited ability to regenerate after damage, which can lead to incomplete healing. Previous studies focussed on single interfaces, most commonly bone-tendon and bone-cartilage interfaces. Herein, we develop a 3D in vitro model to study the regeneration of the bone-tendon-muscle interface. The 3D model was prepared from collagen and agarose, with different concentrations of hydroxyapatite to graduate the tissues from bones to muscles, resulting in a stiffness gradient. This graduated structure was fabricated using indirect 3D printing to provide biologically relevant surface topographies. MG-63, human dermal fibroblasts, and Sket.4U cells were found suitable cell models for bones, tendons, and muscles, respectively. The biphasic and triphasic hydrogels composing the 3D model were shown to be suitable for cell growth. Cells were co-cultured on the 3D model for over 21 days before assessing cell proliferation, metabolic activity, viability, cytotoxicity, tissue-specific markers, and matrix deposition to determine interface formations. The studies were conducted in a newly developed growth chamber that allowed cell communication while the cell culture media was compartmentalised. The 3D model promoted cell viability, tissue-specific marker expression, and new matrix deposition over 21 days, thereby showing promise for the development of new interfaces.

Cohesion mechanisms for bioadhesives

Due to the nature of non-invasive wound closure, the ability to close different forms of leaks, and the potential to immobilize various devices, bioadhesives are altering clinical practices. As one of the vital factors, bioadhesives' strength is determined by adhesion and cohesion mechanisms. As well as being essential for adhesion strength, the cohesion mechanism also influences their bulk functions and the way the adhesives can be applied. Although there are many published reports on various adhesion mechanisms, cohesion mechanisms have rarely been addressed. In this review, we have summarized the most used cohesion mechanisms. Furthermore, the relationship of cohesion strategies and adhesion strategies has been discussed, including employing the same functional groups harnessed for adhesion, using combinational approaches, and exploiting different strategies for cohesion mechanism. By providing a comprehensive insight into cohesion strategies, the paper has been integrated to offer a roadmap to facilitate the commercialization of bioadhesives.

Establishment of a luciferase-based method for measuring cancer cell adhesion and proliferation

BACKGROUND

Methods measuring cell proliferation and adhesion are widely used but each hold limitations. We, therefore, introduce novel methods for measuring cell proliferation and adhesion based on CRISPR-modified cancer cell lines secreting luciferase to the growth media.

MATERIALS AND METHODS

Using CRISPR genome editing, we generated stable luciferase-secreting LS174T, HCT 116, Caco-2, and PANC-1 cell lines. The modified cells were seeded, and luciferase activity was measured in the media and compared to Coulter counter cell counts and iCELLigence impedance assay to evaluate the value of the secreted luciferase activities as a measurement for adhesion and proliferation.

RESULTS

Our results demonstrate that luciferase secreted into the media can be used quantifying cell proliferation and adhesion. The adhesion luciferase assay and the iCELLigence impedance assay showed similar results with increased significant difference observed in the luciferase assays. The luciferase proliferation assay showed increased growth following increased serum concentrations in all cell lines vs. only two cell lines in the iCELLigence impedance assay.

CONCLUSIONS

Our results show that the luciferase adhesion and proliferation assays are reliable methods for measuring adhesion and proliferation. The luciferase assays have advantages over existing assays as they are highly sensitive, easy to perform, non-invasive and suitable as high-throughput measurements.

Extracellular Nucleotides Affect the Proangiogenic Behavior of Fibroblasts, Keratinocytes, and Endothelial Cells

Chronic wound healing is currently a severe problem due to its incidence and associated complications. Intensive research is underway on substances that retain their biological activity in the wound microenvironment and stimulate the formation of new blood vessels critical for tissue regeneration. This group includes synthetic compounds with proangiogenic activity. Previously, we identified phosphorothioate analogs of nucleoside 5′-O-monophosphates as multifunctional ligands of P2Y6 and P2Y14 receptors. The effects of a series of unmodified and phosphorothioate nucleotide analogs on the secretion of VEGF from keratinocytes and fibroblasts, as well as their influence on the viability and proliferation of keratinocytes, fibroblasts, and endothelial cells were analyzed. In addition, the expression profiles of genes encoding nucleotide receptors in tested cell models were also investigated. In this study, we defined thymidine 5′-O-monophosphorothioate (TMPS) as a positive regulator of angiogenesis. Preliminary analyses confirmed the proangiogenic potency of TMPS in vivo.

Mechanistic Insight in Surface Nanotopography Driven Cellular Migration

Cellular migration plays a vital role in many physiological processes. To elucidate the role of surface nanotopography on the downstream signaling pathways underlying cell migration, model surfaces having well-defined hill-like surface nanotopography and uniform surface chemistry were designed and implemented using plasma polymerization and covalent attachment of nanoparticles of predetermined size. A scratch wound assay, immunostaining, and gene expression of focal adhesion (FA) proteins were performed to determine the influence of surface nanotopography on cell migration. The results of this study demonstrate that the gap closure between cell monolayers is faster on surfaces having greater nanoscale topography. The phenomenon is predominantly driven by cell migration and was independent from cell proliferation. Qualitative and quantitative assessment of proteins involved in the signaling pathways underlying cell migration showed significant modulation by surface nanotopography. Specifically, focal adhesion sites decreased with the increase in surface nanotopography scale while the expression of FA proteins increased. This implies that nanotopography mediated modulation of cell migration is directly governed by the recruitment of receptor and adapter proteins responsible for cell-surface interaction. The results of this study indicate that biomaterial devices and constructs having rationally designed surface nanotopography and chemistry could be utilized to regulate wound healing and tissue regeneration.

Betulinic Acid-Doxorubicin-Drug Combination Induced Apoptotic Death via ROS Stimulation in a Relapsed AML MOLM-13 Cell Model

In this study, cell death regulation and induction in AML cell line from a relapsed MLL-rearranged cell model (MOLM-13) was investigated with doxorubin (Dox) and betulinic acid (BetA), singly and in combination. CyQUANT Direct^® and Annexin V/propidium iodide double staining were used to measure the cytotoxic and cell death induction effects of the compounds, respectively. Reactive oxygen species (ROS) generation was measured using 2′,7′-dichlorofluorescin diacetate staining. Expressions of proteins and genes were examined by Western blot and reverse transcription polymerase chain reaction analysis, respectively. BetA (20 μM) and Dox (1 μM) indicated a synergistic growth inhibitory effect on MOLM-13 cells. The combined drug caused more cells to reside in irreversible late apoptotic stage compared to the single treatments (p < 0.05). Elevation in ROS may be the synergistic mechanism involved in MOLM-13 cell death since ROS can directly disrupt mitochondrial activity. In contrast, in leukaemic U-937 cells, the combination treatments attenuated Dox-induced cell death. Dox and the drug combination selectively reduced (p < 0.05) a recently reported anti-apoptotic Bcl-2 protein isoform p15-20-Bcl-2 in MOLM-13 by our group, without affecting the usually reported p26-Bcl-2-α. Further studies using known inhibitors of apoptosis are required to confirm the potential of Dox-BetA combination to modulate these pathways.

DNA Dyes-Highly Sensitive Reporters of Cell Quantification: Comparison with Other Cell Quantification Methods

Cell quantification is widely used both in basic and applied research. A typical example of its use is drug discovery research. Presently, plenty of methods for cell quantification are available. In this review, the basic techniques used for cell quantification, with a special emphasis on techniques based on fluorescent DNA dyes, are described. The main aim of this review is to guide readers through the possibilities of cell quantification with various methods and to show the strengths and weaknesses of these methods, especially with respect to their sensitivity, accuracy, and length. As these methods are frequently accompanied by an analysis of cell proliferation and cell viability, some of these approaches are also described.

Environmentally Relevant Levels of Depleted Uranium Impacts Dermal Fibroblast Proliferation, Viability, Metabolic Activity, and Scratch Closure

Uranium (U) is a heavy metal used in military and industrial settings, with a large portion being mined from the Southwest region of the United States. Uranium has uses in energy and military weaponry, but the mining process has released U into soil and surface waters that may pose threats to human and environmental health. The majority of literature regarding U's human health concern focuses on outcomes based on unintentional ingestion or inhalation, and limited data are available about its influence via cutaneous contact. Utilizing skin dermis cells, we evaluated U's topical chemotoxicity. Employing soluble depleted uranium (DU) in the form of uranyl nitrate (UN), we hypothesized that in vitro exposure of UN will have cytotoxic effects on primary dermal fibroblasts by affecting cell viability and metabolic activity and, further, may delay wound healing aspects via altering cell proliferation and migration. Using environmentally relevant levels of U found in water (0.1 μM to 100 μM [UN]; 23.8-23,800 ppb [U]), we quantified cellular mitosis and migration through growth curves and in vitro scratch assays. Cells were exposed from 24 h to 144 h for a time-course evaluation of UN chemical toxicity. The effects of UN were observed at concentrations above and below the Environmental Protection Agency threshold for safe exposure limits. UN exposure resulted in a dose-dependent decrease in the viable cell count; however, it produced an increase in metabolism when corrected for the viable cells present. Furthermore, cellular proliferation, population doubling, and percent closure was hindered at levels ≥10 μM UN. Therefore, inadvertent exposure may exacerbate pre-existing skin diseases in at-risk demographics, and additionally, it may substantially interfere in cutaneous tissue repair processes.

Imidazopyridazine Acetylcholinesterase Inhibitors Display Potent Anti-Proliferative Effects in the Human Neuroblastoma Cell-Line, IMR-32

Imidazo[1,2-b]pyridazine compounds are a new class of promising lead molecules to which we have incorporated polar nitro and amino moieties to increase the scope of their biological activity. Two of these substituted 3-nitro-6-amino-imidazo[1,2-b]pyridazine compounds (5c and 5h) showed potent acetylcholinesterase (AChE) inhibitory activity (IC₅₀ 40–50 nM), which we have previously reported. In this study, we wanted to test the biological efficacy of these compounds. Cytotoxicity assays showed that compound 5h mediated greater cell death with over 43% of cells dead at 100 μM and activation of caspase 3-mediated apoptosis. On the other hand, compound 5c mediated a dose-dependent decrease in cell proliferation. Both compounds showed cell cycle arrest in the G₀/G₁ phase and reduced cellular ATP levels leading to activation of adenosine monophosphate-activated protein kinase (AMPK) and enhanced mitochondrial oxidative stress. It has to be noted that all these effects were observed at doses beyond 10 μM, 200-fold above the IC₅₀ for AChE inhibition. Both compounds also inhibited bacterial lipopolysaccharide-mediated cyclooxygenase-2 and nitric oxide release in primary rat microglial cells. These results suggested that the substituted imidazo (1,2-b) pyridazine compounds, which have potent AChE inhibitory activity, were also capable of antiproliferative, anti-migratory, and anti-inflammatory effects at higher doses.

Chronic AdipoRon Treatment Mimics the Effects of Physical Exercise on Restoring Hippocampal Neuroplasticity in Diabetic Mice

Administration of exercise mimetic drugs could be a novel therapeutic approach to combat comorbid neurodegeneration and metabolic syndromes. Adiponectin is an adipocyte-secreted hormone. In addition to its antidiabetic effect, adiponectin mediates the antidepressant effect of physical exercise associated with adult hippocampal neurogenesis. The antidiabetic effect of the adiponectin receptor agonist AdipoRon has been demonstrated, but its potential pro-cognitive and neurotrophic effects in the hippocampus under diabetic condition are still unclear. This study reported that chronic AdipoRon treatment for 2 weeks improved hippocampal-dependent spatial recognition memory in streptozotocin-induced diabetic mice. Besides, AdipoRon treatment increased progenitor cell proliferation and neuronal differentiation in the hippocampal dentate gyrus (DG) of diabetic mice. Furthermore, AdipoRon treatment significantly increased dendritic complexity, spine density, and N-methyl-D-aspartate receptor-dependent long-term potentiation (LTP) in the dentate region, and increased BDNF levels in the DG of diabetic mice. AdipoRon treatment activated AMPK/PGC-1α signalling in the DG, whereas increases in cell proliferation and LTP were not observed when PGC-1α signalling was pharmacologically inhibited. In sum, chronic AdipoRon treatment partially mimics the benefits of physical exercise for learning and memory and hippocampal neuroplasticity in the diabetic brain. The results suggested that AdipoRon could be a potential physical exercise mimetic to improve hippocampal plasticity and hence rescue learning and memory impairment typically associated with diabetes.

Cannabidiol-Driven Alterations to Inflammatory Protein Landscape of Lipopolysaccharide-Activated Macrophages In Vitro May Be Mediated by Autophagy and Oxidative Stress

Background: The nonpsychotropic phytocannabinoid cannabidiol (CBD) presents itself as a potentially safe and effective anti-inflammatory treatment relative to clinical standards. In this present study, we compare the capacity of CBD to the corticosteroid dexamethasone (Dex) in altering the secreted protein landscape of activated macrophages and speculate upon the mechanism underpinning these alterations. Materials and Methods: Human THP-1 monocytes were differentiated into macrophages (THP-1 derived macrophages [tMACs]), activated with lipopolysaccharide (LPS), and then treated with 5, 10, 25, 50, or 100 μM CBD or 10 μM Dex for 24 h. Following treatment, cytotoxicity of CBD and protein expression levels from culture supernatants and from whole cell lysates were assessed for secreted and intracellular proteins, respectively. Results: High concentration (50 and 100 μM) CBD treatments exhibit a cytotoxic effect on LPS-activated tMACs following the 24-h treatment. Relative to the LPS-activated and untreated control (M[LPS]), both 25 μM CBD and 10 μM Dex reduced expression of pro-inflammatory markers-tumor necrosis factor alpha, interleukin 1 beta, and regulated on activation, normal T cell expressed and secreted (RANTES)-as well as the pleiotropic marker interleukin-6 (IL-6). A similar trend was observed for anti-inflammatory markers interleukin-10 and vascular endothelial growth factor (VEGF). Dex further reduced secreted levels of monocyte chemoattractant protein-1 in addition to suppressing IL-6 and VEGF beyond treatments with CBD. The anti-inflammatory capacity of 25 μM CBD was concurrent with reduction in levels of phosphorylated mammalian target of rapamycin Ser 2448, endothelial nitric oxide synthase, and induction of cyclooxygenase 2 relative to M(LPS). This could suggest that the observed effects on macrophage immune profile may be conferred through inhibition of mammalian target of rapamycin complex 1 and ensuing induction of autophagy. Conclusion: Cumulatively, these data demonstrate cytotoxicity of high concentration CBD treatment. The data reported herein largely agree with other literature demonstrating the anti-inflammatory effects of CBD. However, there is discrepancy within literature surrounding efficacious concentrations and effects of CBD on specific secreted proteins. These data expand upon previous work investigating the effects of CBD on inflammatory protein expression in macrophages, as well as provide insight into the mechanism by which these effects are conferred.

Cellular metabolism and IL-6 concentrations during stimulated inflammation in primary fibroblasts from small and large dog breeds as they age

The immune system undergoes marked changes during aging characterized by a state of chronic, low-grade inflammation termed 'inflammaging'. We explore this phenomenon in domestic dogs, which are the most morphologically and physiologically diverse group of mammals, with the widest range in body sizes for a single species. Additionally, smaller dogs tend to live significantly longer than larger dogs across all breeds. Body size is intricately linked to mass-specific metabolism and aging rates, which suggests that dogs are exemplary for studies in inflammaging. Dermal fibroblast cells play an important role in skin inflammation, making them a good model for inflammatory patterns across dog breed, body sizes and ages. Here, we examined aerobic and glycolytic cellular metabolism, and IL-6 concentrations in primary fibroblast cells isolated from small and large dog breeds, that were either recently born puppies or old dogs after death. We found no differences in cellular metabolism when isolated fibroblasts were treated with lipopolysaccharide (LPS) from Escherichia coli to stimulate an inflammatory phenotype. Unlike responses observed in mice and humans, there was a less drastic amplification of IL-6 concentration after LPS treatment in the geriatric population of dogs compared with recently born dogs. In young dogs, we also found evidence that untreated fibroblasts from large breeds had significantly lower IL-6 concentrations than observed for smaller breeds. This implies that the patterns of inflammaging in dogs may be distinct and different from other mammals commonly studied.

Effects of metformin, rapamycin, and resveratrol on cellular metabolism of canine primary fibroblast cells isolated from large and small breeds as they age

Small breed dogs have longer lifespans than their large breed counterparts. Previous work demonstrated that primary fibroblast cells isolated from large breed young and old dogs have a persistent glycolytic metabolic profile compared with cells from small breed dogs. Here, we cultured primary fibroblast cells from small and large, young and old dogs and treated these cells with three commercially available drugs that show lifespan and health span benefits, and have been shown to reduce glycolytic rates: rapamycin (rapa), resveratrol (res) and metformin (met). We then measured aerobic and anaerobic cellular respiration in these cells. We found that rapa and res increased rates of non-glycolytic acidification in small and large breed puppies and basal oxygen consumption rates (OCR) in small and large breed puppies. Rapa increased proton leak and non-mitochondrial respiration in small and large breed puppies. Maximal respiration was significantly altered with rapa treatment but in opposing ways: large breed puppies showed a significant increase in maximal respiration when treated with rapa, and small old dogs demonstrated a significant decrease in maximal respiration when treated with rapa. In opposition to rapa treatments, met significantly decreased basal OCR levels in cells from small and large breed puppies. Our data suggest that rapa treatments may be metabolically beneficial to dogs when started early in life and more beneficial in larger breeds.

Poloxamer 188 Protects Isolated Adult Mouse Cardiomyocytes from Reoxygenation Injury

Reperfusion injury is a complex pathological event involving processes that can lead to further disruption of the cell membrane and function following an ischemic event. Return of blood flow allows for the needed reperfusion; however, for a period of time before remaining viable cells stabilize, reperfusion results in additional cellular injury. In cardiomyocytes, loss of membrane integrity allows abnormal influx of extracellular calcium, leading to hyper-contracture and cell death. Methods to improve the membrane integrity of cardiomyocytes overwhelmed by pathological disruptions, such as reperfusion injury, are needed to prevent cell death, because of the myocardium's limited ability to regenerate. Research has shown administration of the copolymer P(oloxamer) 188 before ischemia/reperfusion can protect cardiomyocytes through membrane stabilization. This study sought to determine whether the administration of P188 at the beginning of the clinically more relevant time of reperfusion after ischemia will attenuate any additional damage to cardiomyocytes by stabilizing membrane integrity to allow the cells to maintain function. Using an in-vitro cardiomyocyte model subjected to hypoxia/reoxygenation to simulate ischemia/reperfusion injury, we show that reoxygenation significantly potentiates the injury caused by hypoxia itself. P188, with its unique combination of hydrophobic and hydrophilic chemical properties, and only delivered at the beginning of reoxygenation, dose-dependently protected cardiomyocytes from injury due to reoxygenation by repairing cell membranes, decreasing calcium influx, and maintaining cellular morphology. Our study also shows the hydrophobic portion of P188 is necessary for the stabilization of cell membrane integrity in providing protection to cardiomyocytes against reoxygenation injury.

Quantification of Adeno-Associated Virus with Safe Nucleic Acid Dyes

Adeno-associated virus (AAV) is the most commonly used viral vector for both biological and gene therapeutic applications. Although many methods have been developed to measure quantity attributes of AAV, they are often technically challenging and time-consuming. Here, we report a method to titer AAV with GelGreen^® dye, a safe green fluorescence nucleic acid dye recently engineered by Biotium company (Fremont, CA). This method, hereinafter referred to as GelGreen method, provides a fast (∼30 min) and reliable strategy for AAV titration. To validate GelGreen method, we measured genome titer of an AAV reference material AAV8RSM and compared our titration results with those determined by Reference Material Working Group (ARMWG). We showed that GelGreen results and capsid enzyme-linked immunosorbent assay results are comparable with each other. We also showed that GelRed^® dye, a red fluorescence dye from Biotium, can be used to directly "visualize" AAV genome titer on a conventional gel imager, presenting an especially direct approach to estimate viral quantity. Finally, we showed that GelGreen and GelRed dyes can also be used to quantify self-complementary AAV (scAAV) and crudely purified AAV samples. In summary, we described a technique to titer AAV by using new generation of safe DNA dyes. This technique is simple, safe, reliable, and cost efficient. It has potential to be broadly applied for quantifying and normalizing AAV viral vectors.

Investigation of a cyanine dye assay for the evaluation of the biocompatibility of magnesium alloys by direct and indirect methods

Magnesium and its alloys are promising candidates for a new generation of biodegradable metals in orthopaedic applications due to their excellent biocompatibility, biodegradability, and mechanical properties that are similar to natural bone. However, direct in vitro assessment of these materials in the presence of cells is complicated by degradation products from the alloy that lead to a false positive for the most commonly used cell adhesion and cell proliferation assays. In this paper, a cyanine dye was used to quantitatively evaluate the in vitro biocompatibility of a Mg AZ31 alloy by both direct and indirect methods. The cytotoxicity of the corrosion products was evaluated via an indirect method; a 25% decrease in cell viability compared to control samples was observed. Moreover, direct assessment of cell adhesion and proliferation showed a statistically significant increase in cell number at the surface after 72 h. In addition, the degradation rate and surface characteristics of the Mg AZ31 alloy were evaluated for both direct and indirect tests. The degradation rate was unaffected by the presence of cells while evidence of an increase in calcium phosphate deposition on the magnesium alloy surface in the presence of cells was observed. This study demonstrates that a cyanine dye based assay provides a more accurate assessment of the overall in vitro biocompatibility of biodegradable metals than the more commonly used assays reported in the literature to date.

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Quantitative analysis of cell numbers on the surface of magnesium has been performed.

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No false positive was observed.

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Cyanine dye assays are an excellent alternative to tetrazolium salts for in vitro evaluation of bioabsorbable implants.

Chemosensory bitter taste receptors T2R4 and T2R14 activation attenuates proliferation and migration of breast cancer cells

The emerging significance of the bitter taste receptors (T2Rs) role in the extraoral tissues alludes to their potential role in many pathophysiological conditions. The dysregulation of T2R expression and function in disease conditions has now been demonstrated in airways diseases, neurological disorders, and in some cancers. However, the role of T2Rs in the pathophysiology of breast cancer is unexplored thus far. Previously, we demonstrated differential expression of the 25 T2Rs in breast cancer (BC) cells. Based on our previous findings we selected two T2Rs, T2R4 and T2R14 for this work. The objective of the current study is to investigate the expression of T2R4 and T2R14 in BC clinical samples and to examine their physiological role using highly metastatic BC and non-cancerous cell lines. Using approaches, which involve receptor knockdown, pharmacological activation and biochemical assays we report that (i) T2R4 and T2R14 expression patterns are dissimilar, with decreased levels of T2R4 and increased levels of T2R14 in BC clinical samples compared to non-cancerous controls. (ii) Activation of T2Rs with their respective agonist elicited physiological responses in metastatic breast cancer cells, and no responses were seen in non-tumorigenic breast epithelial cells. (iii) Agonist activation of T2Rs (irrespective of T2R subtype) induced anti-proliferative, pro-apoptotic, and anti-migratory responses in highly metastatic breast cancer cells. Taken together, our findings demonstrate that the chemosensory T2R signaling network is involved in evoking physiological responses in the metastatic breast cancer cell line.

Cell-Type-Specific Quantification of a Scaffold-Based 3D Liver Co-Culture

In order to increase the metabolic activity of human hepatocytes and liver cancer cell lines, many approaches have been reported in recent years. The metabolic activity could be increased mainly by cultivating the cells in 3D systems or co-cultures (with other cell lines). However, if the system becomes more complex, it gets more difficult to quantify the number of cells (e.g., on a 3D matrix). Until now, it has been impossible to quantify different cell types individually in 3D co-culture systems. Therefore, we developed a PCR-based method that allows the quantification of HepG2 cells and 3T3-J2 cells separately in a 3D scaffold culture. Moreover, our results show that this method allows better comparability between 2D and 3D cultures in comparison to the often-used approaches based on metabolic activity measurements, such as the conversion of resazurin.

Ketogenic diet combined with antioxidant N-acetylcysteine inhibits tumor growth in a mouse model of anaplastic thyroid cancer

BACKGROUND

Anaplastic thyroid cancer is an aggressive and fatal malignancy. Many advanced cancers are characterized by glucose dependency, leading to oxidative stress and cellular proliferation. Therefore, we sought to determine if a low glucose environment (in vitro) or a ketogenic diet (in vivo) could inhibit anaplastic thyroid cancer tumor growth when combined with the antioxidant N-acetylcysteine.

METHODS

In vivo, nude mice were injected with the anaplastic thyroid cancer cell line 8505C (n = 6/group). Group 1 was fed a standard diet; Group 2 was fed a ketogenic diet; Group 3 was given standard diet with N-acetylcysteine (40 mM in the drinking water); and Group 4 was fed ketogenic diet with N-acetylcysteine. Tumor volumes, ketones, and glucose were measured. H&E stains and immunohistochemistry for Ki-67 and Caspase 3 were performed on the tumors. In vitro, 8505C cells were cultured in high glucose (25 mM), low glucose (3 mM), high glucose plus N-acetylcysteine (200 uM), or low glucose plus N-acetylcysteine for 96 hours. We performed CyQUANT proliferation (Thermo Fisher Scientific, Waltham, MA), Seahorse glycolytic stress (Agilent, Santa Clara, CA), and reactive oxidative stress assays.

RESULTS

Ketogenic diet plus N-acetylcysteine decreased in vivo tumor volume compared to standard diet (22.5 ± 12.4 mm³ vs 147 ± 54.4 mm³, P < .05) and standard diet plus N-acetylcysteine (P < .05). Blood ketone levels were significantly higher for the mice in the ketogenic diet group compared to standard diet (1.74 mmol/L vs 0.38 mmol/L at week 5, P < .001). However, blood glucose levels were not significantly different between ketogenic diet and standard diet groups. Cells cultured in low glucose plus N-acetylcysteine had significantly reduced proliferation compared to high glucose (98.1 ± 5.0 relative fluorescence units vs 157.8 ± 2.1 relative fluorescence units, P < .001). Addition of N-acetylcysteine to low glucose lowered glycolysis function compared to high glucose (39.0 ± 2.2 mpH/min/cell vs 89.1 ± 13.2 mpH/min/cell, P < .001) and high glucose plus N-acetylcysteine (37.4 ± 2.5 mpH/min/cell vs 70.3 ± 3.3 mpH/min/cell, P < .001). Low glucose plus N-acetylcysteine decreased reactive oxidative stress compared to high glucose (119 ± 34.7 relative fluorescence units vs 277 ± 16.0 relative fluorescence units, P = .014).

CONCLUSION

The combination of a ketogenic diet or glucose restriction with the antioxidant- N-acetylcysteine significantly reduced tumor growth in vivo and in vitro. Further studies are warranted to explore these metabolic therapies in anaplastic thyroid cancer.

Knockdown of TM9SF4 boosts ER stress to trigger cell death of chemoresistant breast cancer cells

Drug resistance is one of the major obstacles to breast cancer therapy. However, the mechanisms of how cancer cells develop chemoresistance are still not fully understood. In the present study, we found that expression of TM9SF4 proteins was much higher in adriamycin (ADM)-resistant breast cancer cells MCF-7/ADM than in its parental line wild-type breast cancer cells MCF-7/WT. shRNA-mediated knockdown of TM9SF4 preferentially reduced cell growth and triggered cell death in chemoresistant MCF-7/ADM cells compared with MCF-7/WT cells. Knockdown of TM9SF4 also reduced cell growth and triggered cell death in chemoresistant MDA-MB-231/GEM cells. Mechanistic studies showed that TM9SF4 knockdown increased protein misfolding and elevated endoplasmic reticulum (ER) stress level in MCF-7/ADM cells, as indicated by aggresome formation and upregulated expression of ER stress markers, the effect of which was reversed by a small molecule chaperone 4-phenybutyric acid. In an athymic nude mouse model of ADM-resistant human breast xenograft tumor, knockdown of TM9SF4 decreased the growth of tumor xenografts. In chemoresistant breast cancer patients, chemotherapy increased the expression of TM9SF4 proteins in breast tumor samples. Taken together, these results uncovered a novel role of TM9SF4 proteins in alleviating ER stress and protecting chemoresistant breast cancer cells from apoptotic/necrotic cell death. These results highlight a possible strategy of targeting TM9SF4 to overcome breast cancer chemoresistance.

Antioxidant-Rich Extracts of Terminalia ferdinandiana Interfere with Estimation of Cell Viability

The impact of plant extracts and phytochemicals on in vitro cell viability is usually assessed by employing cell viability assays dependent upon the activity of dehydrogenase enzymes. The CellTiter 96^® AQ_ueous One Solution Cell Proliferation Assay (CellTiter) was used to measure cell viability in response to antioxidant-rich extracts of Terminalia ferdinandiana fruits. Conflicting results were obtained from this assay whereby higher concentrations of extracts significantly increased cell viability compared to lower concentrations. Intrinsic reductive potential was observed in a cell-free system when extracts were added directly to the CellTiter assay reagent. To confirm this effect in a similar cell proliferation assay, we employed the CellTiter-Blue^® Cell Viability Assay and again observed increased viability with increased concentrations of the extracts and direct reduction of the assay reagent by the extracts in cell-free systems. In the search for a cell proliferation assay that would not be directly affected by the plant extracts, we identified the CyQUANT^® NF Cell Proliferation Assay that is based on the estimation of DNA content in viable cells. Cell viability decreased with increasing concentrations of the extracts. Accordingly, the results of the present study indicated that cell viability assays reliant upon dehydrogenase activity may lead to false positive results when testing antioxidant-rich plant extracts with intrinsic reductive potential, and alternative cell viability assays should be used to measure the cell viability.

Quantification of fixed adherent cells using a strong enhancer of the fluorescence of DNA dyes

Cell quantification is widely used in basic or applied research. The current sensitive methods of cell quantification are exclusively based on the analysis of non-fixed cells and do not allow the simultaneous detection of various cellular components. A fast, sensitive and cheap method of the quantification of fixed adherent cells is described here. It is based on the incubation of DAPI- or Hoechst 33342-stained cells in a solution containing SDS. The presence of SDS results in the quick de-staining of DNA and simultaneously, in an up-to-1,000-fold increase of the fluorescence intensity of the used dyes. This increase can be attributed to the micelle formation of SDS. The method is sufficiently sensitive to reveal around 50–70 human diploid cells. It is compatible with immunocytochemical detections, the detection of DNA replication and cell cycle analysis by image cytometry. The procedure was successfully tested for the analysis of cytotoxicity. The method is suitable for the quantification of cells exhibiting low metabolic activity including senescent cells. The developed procedure provides high linearity and the signal is high for at least 20 days at room temperature. Only around 90 to 120 minutes is required for the procedure’s completion.

FluoroCellTrack: An algorithm for automated analysis of high-throughput droplet microfluidic data

High-throughput droplet microfluidic devices with fluorescence detection systems provide several advantages over conventional end-point cytometric techniques due to their ability to isolate single cells and investigate complex intracellular dynamics. While there have been significant advances in the field of experimental droplet microfluidics, the development of complementary software tools has lagged. Existing quantification tools have limitations including interdependent hardware platforms or challenges analyzing a wide range of high-throughput droplet microfluidic data using a single algorithm. To address these issues, an all-in-one Python algorithm called FluoroCellTrack was developed and its wide-range utility was tested on three different applications including quantification of cellular response to drugs, droplet tracking, and intracellular fluorescence. The algorithm imports all images collected using bright field and fluorescence microscopy and analyzes them to extract useful information. Two parallel steps are performed where droplets are detected using a mathematical Circular Hough Transform (CHT) while single cells (or other contours) are detected by a series of steps defining respective color boundaries involving edge detection, dilation, and erosion. These feature detection steps are strengthened by segmentation and radius/area thresholding for precise detection and removal of false positives. Individually detected droplet and contour center maps are overlaid to obtain encapsulation information for further analyses. FluoroCellTrack demonstrates an average of a ~92-99% similarity with manual analysis and exhibits a significant reduction in analysis time of 30 min to analyze an entire cohort compared to 20 h required for manual quantification.

Polymer conjugation optimizes EDTA as a calcium-chelating agent that exclusively removes extrafibrillar minerals from mineralized collagen

During development of mineralized collagenous tissues, intrafibrillar mineralization is achieved by preventing mineralization precursor inhibitors that are larger than 40 kDa from entering the collagen fibrils. Such a property is incorporated in the design of a calcium chelator for dentin bonding in the etch-and-rinse technique that selectively demineralizes extrafibrillar apatite while leaving the intrafibrillar minerals intact. This strategy prevents complete demineralization of collagen fibrils, avoids collapse of collagen that blocks resin infiltration after air-drying, and protects the completely demineralized fibrils from bacteria colonization and degradation by endogenous proteases after resin bonding. In the present study, a water-soluble glycol chitosan-EDTA (GCE) conditioner was synthesized by conjugation of EDTA, an effective calcium chelator, to high molecular weight glycol chitosan, which exhibits weak chelation property. The GCE conjugate was purified, characterized by FTIR, ¹H NMR, isothermal titration calorimetry and ICP-AES, and subjected to size exclusion dialysis to recover molecules that are >40 kDa. The optimal concentration and application time for etching dentin were determined by bond strength testing to ensure that the dentin bonding results were comparable to phosphoric acid etching, and maintained equivalent bond strength after air-drying of the conditioned collagen matrix. Extrafibrillar demineralization was validated with transmission electron microscopy. Inhibition of endogenous dentin proteases was confirmed using in-situ zymography. The water-soluble GCE dentin conditioner was non-cytotoxic and possessed antibacterial activities against planktonic and single-species biofilms, supporting its ongoing development as a dentin conditioner with air-drying, anti-proteolytic and antibacterial properties to enhance the durability of bonds created using the etch-and-rinse bonding technique. STATEMENT OF SIGNIFICANCE: The current state-of-the-art techniques for filling decayed teeth with plastic tooth-colored materials require conditioning the mineralized, biofilm-covered, decayed dentin with acids or acid resin monomers to create a surface layer of completely- or partially-demineralized collagen matrix for the infiltration of adhesive resin monomers. Nevertheless, fillings prepared using these strategies are not as durable as consumers have anticipated. Conjugation of polymeric glycol chitosan with EDTA produces a new conditioner for dentin bonding that demineralizes only extrafibrillar dentin, reduces endogenous protease activities and kills biofilm bacteria. The high molecular weight glycol chitosan-EDTA is non-cytotoxic to the key regenerative players within the dentin-pulp complex. This advance permits dry bonding and the use of hydrophobic resins.

Adaptive Changes of Glioblastoma Cells Following Exposure to Hypoxic (1% Oxygen) Tumour Microenvironment

Glioblastoma multiforme is the most aggressive and malignant primary brain tumour, with a median survival rate of between 15 to 17 months. Heterogeneous regions occur in glioblastoma as a result of oxygen gradients which ranges from 0.1% to 10% in vivo. Emerging evidence suggests that tumour hypoxia leads to increased aggressiveness and chemo/radio resistance. Yet, few in vitro studies have been performed in hypoxia. Using three glioblastoma cell-lines (U87, U251, and SNB19), the adaptation of glioblastoma cells in a 1% (hypoxia) and 20% (normoxia) oxygen microenvironment on proliferation, metabolism, migration, neurosphere formation, CD133 and VEGF expression was investigated. Compared to cells maintained in normoxia (20% oxygen), glioblastoma cells adapted to 1% oxygen tension by reducing proliferation and enhancing metabolism. Both migratory tendency and neurosphere formation ability were greatly limited. In addition, hypoxic-mediated gene upregulation (CD133 and VEGF) was reversed when cells were removed from the hypoxic environment. Collectively, our results reveal that hypoxia plays a pivotal role in changing the behaviour of glioblastoma cells. We have also shown that genetic modulation can be reversed, supporting the concept of reversibility. Thus, understanding the degree of oxygen gradient in glioblastoma will be crucial in personalising treatment for glioblastoma patients.

NRG1 type I dependent autoparacrine stimulation of Schwann cells in onion bulbs of peripheral neuropathies

In contrast to acute peripheral nerve injury, the molecular response of Schwann cells in chronic neuropathies remains poorly understood. Onion bulb structures are a pathological hallmark of demyelinating neuropathies, but the nature of these formations is unknown. Here, we show that Schwann cells induce the expression of Neuregulin-1 type I (NRG1-I), a paracrine growth factor, in various chronic demyelinating diseases. Genetic disruption of Schwann cell-derived NRG1 signalling in a mouse model of Charcot-Marie-Tooth Disease 1A (CMT1A), suppresses hypermyelination and the formation of onion bulbs. Transgenic overexpression of NRG1-I in Schwann cells on a wildtype background is sufficient to mediate an interaction between Schwann cells via an ErbB2 receptor-MEK/ERK signaling axis, which causes onion bulb formations and results in a peripheral neuropathy reminiscent of CMT1A. We suggest that diseased Schwann cells mount a regeneration program that is beneficial in acute nerve injury, but that overstimulation of Schwann cells in chronic neuropathies is detrimental.

Onion bulbs are a hallmark of demyelinating peripheral neuropathies. Here the authors identify Neuregulin-1 type I expression in Schwann cells as an essential mechanism involved in the formation of these characteristic structures.

Indole Treatment Alleviates Intestinal Tissue Damage Induced by Chicken Coccidiosis Through Activation of the Aryl Hydrocarbon Receptor

Indoles, as the ligands of aryl hydrocarbon receptor (AhR), have been shown to possess immune-modulating property in terms of the balancing between regulatory T cells (Treg) and T helper 17 cells (Th17) activities. In the present study, we examined the effects of dietary indoles, 3,3′-diindolylmethane (DIM) and indole-3-carbinol (I3C), on CD4⁺T cell population and functions in chickens. Furthermore, the effects of dietary DIM treatment on chicken coccidiosis caused by an apicomplexan parasite were investigated. Dietary treatment of healthy chickens with DIM and I3C induced increased CD4⁺CD25⁺ (Treg) cells and the mRNA expression of IL-10, while decreasing number of CD4⁺IL-17A⁺ (Th17) cells and Th17-related cytokines transcripts expression in the intestine. In addition, we explored the role of AhR in indole-treated splenic lymphocytes by using AhR antagonist and our results suggested that DIM is a ligand for chicken AhR. In chicken coccidiosis, treatment of DIM increased the ratio of Treg/Th17 cells and significantly reduced intestinal lesion although no significant changes in body weight and fecal oocyst production were noted compared to non-treated control group. These results indicate that DIM is likely to affect the ratios of Treg/Th17 reducing the level of local inflammatory response induced by Eimeria or facilitate repairing process of inflamed gut following Eimeria infection. The results described herein are thus consistent with the concept that AhR ligand modulates the T cell immunity through the alteration of Treg/Th17 cells with Treg dominance. To our knowledge, present study is the first scientific report showing the effects of dietary indole on T cell immunity in poultry species.

Design, Synthesis and Biological Evaluation of 1H-1,2,3-Triazole-Linked-1H-Dibenzo[b,h]xanthenes as Inductors of ROS-Mediated Apoptosis in the Breast Cancer Cell Line MCF-7

BACKGROUND

Low molecular weight 1,2,3-triazoles and naphthoquinones are endowed with various types of biological activity, such as against cancer, HIV and bacteria. However, in some cases, the conjugation of these two nuclei considerably increases their biological activities.

OBJECTIVE

In this work, we decided to study the synthesis and screening of bis-naphthoquinones and xanthenes tethered to 1,2,3-triazoles against cancer cell lines, specifically the human breast cancer cell line MCF-7.

RESULTS

Starting from lawsone and aryl-1H-1,2,3-triazole-4-carbaldehydes (10a-h) several new 7- (1-aryl-1H-1,2,3-triazol-4-yl)-6H-dibenzo[b,h]xanthene-5,6,8,13(7H)-tetraones (12a-h) and 3,3'- ((1-aryl-1H-1,2,3-triazol-4-yl)methylene)bis(2-hydroxynaphthalene-1,4-diones) 11a-h were synthesized and evaluated for their cytotoxic activities using the human breast cancer cell line MCF-7 and the non-tumor cell line MCF10A as control. We performed test of cell viability, cell proliferation, intracellular ATP content and cell cytometry to determine reactive oxygen species (ROS) formation.

CONCLUSIONS

Based on these results, we found that compound 12a promotes ROS production, interfering with energy metabolism, cell viability and proliferation, and thus promoting whole cell damage.

The Chemical Potential of Plasma Membrane Cholesterol: Implications for Cell Biology

Cholesterol is abundant in plasma membranes and exhibits a variety of interactions throughout the membrane. Chemical potential accounts for thermodynamic consequences of molecular interactions, and quantifies the effective concentration (i.e., activity) of any substance participating in a process. We have developed, to our knowledge, the first method to measure cholesterol chemical potential in plasma membranes. This was accomplished by complexing methyl-β-cyclodextrin with cholesterol in an aqueous solution and equilibrating it with an organic solvent containing dissolved cholesterol. The chemical potential of cholesterol was thereby equalized in the two phases. Because cholesterol is dilute in the organic phase, here activity and concentration were equivalent. This equivalence allowed the amount of cholesterol bound to methyl-β-cyclodextrin to be converted to cholesterol chemical potential. Our method was used to determine the chemical potential of cholesterol in erythrocytes and in plasma membranes of nucleated cells in culture. For erythrocytes, the chemical potential did not vary when the concentration was below a critical value. Above this value, the chemical potential progressively increased with concentration. We used standard cancer lines to characterize cholesterol chemical potential in plasma membranes of nucleated cells. This chemical potential was significantly greater for highly metastatic breast cancer cells than for nonmetastatic breast cancer cells. Chemical potential depended on density of the cancer cells. A method to alter and fix the cholesterol chemical potential to any value (i.e., a cholesterol chemical potential clamp) was also developed. Cholesterol content did not change when cells were clamped for 24-48 h. It was found that the level of activation of the transcription factor STAT3 increased with increasing cholesterol chemical potential. The cholesterol chemical potential may regulate signaling pathways.

Microcolony Size Distribution Assay Enables High-Throughput Cell Survival Quantitation

Cell survival is a critical and ubiquitous endpoint in biology. The broadly accepted colony formation assay (CFA) directly measures a cell's ability to divide; however, it takes weeks to perform and is incompatible with high-throughput screening (HTS) technologies. Here, we describe the MicroColonyChip, which exploits microwell array technology to create an array of colonies. Unlike the CFA, where visible colonies are counted by eye, using fluorescence microscopy, microcolonies can be analyzed in days rather than weeks. Using automated analysis of microcolony size distributions, the MicroColonyChip achieves comparable sensitivity to the CFA (and greater sensitivity than the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide [XTT] assay). Compared to CellTiter-Glo, the MicroColonyChip is as sensitive and also robust to artifacts caused by differences in initial cell seeding density. We demonstrate efficacy via studies of radiosensitivity and chemosensitivity and show that the approach is amenable to multiplexing. We conclude that the MicroColonyChip is a rapid and automated alternative for cell survival quantitation.

Overview of Glutamine Dependency and Metabolic Rescue Protocols

Enhanced glutaminolysis and glycolysis are the two most remarkable biochemical features of cancer cell metabolism, reflecting increased utilization of glutamine and glucose in proliferating cells. Most solid tumors often outgrow the blood supply, resulting in a tumor microenvironment characterized by the depletion of glutamine, glucose, and oxygen. Whereas mechanisms by which cancer cells sense and metabolically adapt to hypoxia have been well characterized with a variety of cancer types, mechanisms by which different types of tumor cells respond to a dynamic change of glutamine availability and the underlying importance remains to be characterized. Here we describe the protocol, which uses cultured Hep3B cells as a model in determining glutamine-dependent proliferation, metabolite rescuing, and cellular responses to glutamine depletion. These protocols may be modified to study the metabolic roles of glutamine in other types of tumor or non-tumor cells as well.

PSMA Antibody-Conjugated Pentablock Copolymer Nanomicellar Formulation for Targeted Delivery to Prostate Cancer

The main purpose of this study was to develop a prostate-specific membrane antigen (PSMA) antibody-conjugated drug-loaded nanomicelles using MPEG--PLA-PCL-PLA-PEG-NH2 pentablock copolymer for targeted delivery of hydrophobic anticancer drugs to prostate cancer cells. During this experiment, monomers of L-lactide, ε-caprolactone, poly(ethylene glycol)-methyl ether, and poly(ethylene glycol)-NH2 were used to prepare pentablock copolymer using the ring opening technique. The pentablock nanomicellar (PBNM) formulation was prepared by the evaporation-rehydration method. The resultant pentablock nanomicelles were then conjugated with PSMA antibody resulting in PSMA-Ab-PTX-PBNM. Both the block copolymers and the nanomicelles were analyzed by hydrogen nuclear magnetic resonance (H-NMR), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The obtained nanomicelles (NM) were then analyzed for size and zeta potential using dynamic light scattering-dynamic laser scattering (DLS) and then further submitted to H-NMR and TEM analyses. The XRD, FTIR, and the H-NMR analyses confirmed the structure of the pentablock copolymers. The average size for conjugated nanomicellar was 45 nm ± 2.5 nm. The average (ζ-potential) was around - 28 mV. H-NMR and FTIR analysis done on PSMA-coupled paclitaxel-loaded PBNM showed peaks characteristic of the drug (paclitaxel) and the polymer, confirming the successful encapsulation. TEM analysis showed well-defined spherical morphology and confirmed the size range obtained by the DLS. In vitro release studies revealed sustained slow of PTX in phosphate buffer solution (PBS). Confocal scanning microscopy (TEM) of coumarin6-loaded in PBNM indicated that pentablock nanomicelles were internalized into the prostate cancer (PC-3) cells. Cell proliferation assay showed that nanomicelles ferried paclitaxel into the PC-3 cells and subsequently reduced the cell proliferation. The results depict PTX-PBNM-Ab as a suitable carrier for targeted delivery of drugs to prostate cancer cells.

New antibacterial and 5-lipoxygenase activities of synthetic benzyl phenyl ketones: Biological and docking studies

We investigated twelve benzyl phenyl ketone derivatives which are synthetic precursors of isoflavonoids that are shown be good 5-hLOX inhibitors, especially those that have the catechol group, but these precursors never have been assayed as 5-hLOX inhibitors being a novelty as inhibitors of the enzyme, due to sharing important structural characteristics. Screening assays, half maximal inhibitory concentration (IC₅₀) and kinetic assays of all the studied molecules (5 µg/ml in media assay) showed that 1-(2,4-dihydroxy-3-methylphenyl)-2-(3-chlorophenyl)-ethanone (K205; IC₅₀ = 3.5 µM; K_i = 4.8 µM) and 1-(2,4-dihydroxy-3-methylphenyl)-2-(2-nitrophenyl)-ethanone (K206; IC₅₀ = 2.3 µM; K_i = 0.7 µM) were potent, selective, competitive and nonredox inhibitors of 5-hLOX. Antioxidant behavior was also assayed by DPPH, FRAP, and assessing ROS production, and those with antibacterial and antiproliferative properties relating to 1-(2,4-dihydroxy-3-methylphenyl)-2-(2-chlorophenyl)-ethanone (K208) established it as the most interesting and relevant compound studied, as it showed nearly 100% inhibition of bacterial growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Finally, docking studies were done that helped to characterize how the inhibitor structures correlated to decreased 5-hLOX activity.

Strategic Pentablock Copolymer Nanomicellar Formulation for Paclitaxel Delivery System

Nanomicelles (NM) enhance solubility and absorption of active pharmaceutical ingredients (APIs). Various polymers and non-polymers are utilized to prepare nanomicellar formulations to achieve high absorption and delivery of drugs. The main purpose of this study was to develop drug-loaded nanomicelles with pentablock copolymers for paclitaxel delivery. Monomers of lactide, ε-caprolactone, and polyethylene-glycol were utilized to prepare pentablock copolymer by ring opening technique. The pentablock nanomicelles (PBNM) were formulated by evaporation and rehydration. Both copolymers and nanomicelles were analyzed by H-NMR, FTIR, and XRD. Nanomicelles were further analyzed for size and zeta potential using dynamic light scattering (DLS) and by H-NMR and TEM. The XRD, FTIR, and H-NMR analyses confirmed the structures of the pentablock copolymers. Average size was 20 nm ± 5.00 nm, and ζ-potential is around zero. H-NMR and FTIR analyses for Paclitaxel-PBNM indicated peaks of paclitaxel and the polymer, confirming successful encapsulation. TEM showed spherical morphology and size range similar to that obtained by DLS. In vitro release studies revealed slow first-order paclitaxel release rate from pentablock nanomicelles in phosphate buffer solution (PBS). Confocal laser scanning microscopy analysis with coumarin-6-loaded in PBNM indicated that pentablock nanomicelles were efficiently taken into prostate cancer (PC-3) cells. Cell proliferation assay showed that nanomicelles were able to ferry adequate amounts of paclitaxel drug into PC-3 cells and subsequently inhibiting PC-3 cell proliferation significantly. Results confirmed that pentablock copolymer can generate drug-loaded nanomicelles with desirable sizes and zeta potential. These demonstrate potentiality of pentablock nanomicelles as carrier for anticancer delivery.

Sex differences influencing micro- and macrovascular endothelial phenotype in vitro

KEY POINTS

Endothelial dysfunction is an early hallmark of multiple disease states that also display sex differences with respect to age of onset, frequency and severity. Results of in vivo studies of basal and stimulated microvascular barrier function revealed sex differences that are difficult to ascribe to specific cells or environmental factors. The present study evaluated endothelial cells (EC) isolated from macro- and/or microvessels of reproductively mature rats under the controlled conditions of low-passage culture aiming to test the assumption that EC phenotype would be sex independent. The primary finding was that EC, regardless of where they are derived, retain a sex-bias in low-passage culture, independent of varying levels of reproductive hormones. The implications of the present study include the fallacy of expecting a universal set of mechanisms derived from study of EC from one sex and/or one vascular origin to apply uniformly to all EC under unstimulated conditions, and no less in disease.

ABSTRACT

Vascular endothelial cells (EC) are heterogeneous with respect to phenotype, reflecting at least the organ of origin, location within the vascular network and physical forces. As an independent influence on EC functions in health or aetiology, susceptibility, and progression of dysfunction in numerous disease states, sex has been largely ignored. The present study focussed on EC isolated from aorta (macrovascular) and skeletal muscle vessels (microvascular) of age-matched male and female rats under identical conditions of short-term (passage 4) culture. We tested the hypothesis that genomic sex would not influence endothelial growth, wound healing, morphology, lactate production, or messenger RNA and protein expression of key proteins (sex hormone receptors for androgen and oestrogens α and β; platelet endothelial cell adhesion molecule-1 and vascular endothelial cadherin mediating barrier function; α_v β₃ and N-cadherin influencing matrix interactions; intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 mediating EC/white cell adhesion). The hypothesis was rejected because the EC origin (macro- vs. microvessel) and sex influenced multiple phenotypic characteristics. Statistical model analysis of EC growth demonstrated an hierarchy of variable importance, recapitulated for other phenotypic characteristics, with predictions assuming EC homogeneity < sex < vessel origin < sex and vessel origin. Furthermore, patterns of EC mRNA expression by vessel origin and by sex did not predict protein expression. Overall, the present study demonstrated that accurate assessment of sex-linked EC dysfunction first requires an understanding of EC function by position in the vascular tree and by sex. The results from a single EC tissue source/species/sex cannot provide universal insight into the mechanisms regulating in vivo endothelial function in health, and no less in disease.

Anti-Tumorigenic Effects of Resveratrol in Lung Cancer Cells Through Modulation of c-FLIP

BACKGROUND

Resveratrol has been shown to have antioxidant and anti-proliferative properties in multiple cancer types. Here we demonstrate that H460 lung cancer cells are more susceptible to resveratrol treatment in comparison to human bronchial epithelial Beas-2B cells. Resveratrol decreases cell viability and proliferation, and induces significant apoptosis in H460 cells. The apoptosis observed was accompanied by an increase in hydrogen peroxide (H2O2) production, Bid, PARP and caspase 8 activation, and downregulation of pEGFR, pAkt, c-FLIP and NFkB protein expression. Furthermore, treatment with HH2O2 scavenger catalase significantly inhibited resveratrol-induced c-FLIP downregulation, caspase-8 activation and apoptosis. Overexpression of c-FLIP in H460 cells (FLIP cells) resulted in the inhibition of resveratrol-induced HH2O2 production, and a significant increase in resveratrolinduced apoptosis in comparison to H460 cells. In FLIP cells, catalase treatment did not rescue cells from a decrease in cell viability and apoptosis induction by resveratrol as compared to H460 cells. Resveratrol treatment also led to VEGF downregulation in FLIP cells. Furthermore, inhibition of pEGFR or pAkt using erlotinib and LY294002 respectively, enhanced the negative effect of resveratrol on FLIP cell viability and apoptosis. The reverse was observed when FLIP cells were supplemented with EGF, or transfected with WT-AKT plasmid; resulting in a 20% decrease in resveratrol-induced apoptosis. In addition, transfection with WT-AKT plasmid resulted in the inhibition of pro-apoptotic protein activation, and c-FLIP and pAkt downregulation.

CONCLUSION

Overall, resveratrol induced apoptosis in H460 lung cancer cells by specifically targeting pAkt and c-FLIP dowregulation by proteasomal degradation in a EGFR-dependent manner.

Evaluating the Role of Mitochondrial Function in Cancer-related Fatigue

Fatigue is a common and debilitating condition that affects most cancer patients. To date, fatigue remains poorly characterized with no diagnostic test to objectively measure the severity of this condition. Here we describe an optimized method for assessing mitochondrial function of PBMCs collected from fatigued cancer patients. Using a compact extracellular flux system and sequential injection of respiratory inhibitors, we examined PBMC mitochondrial functional status by measuring basal mitochondrial respiration, spare respiratory capacity, and energy phenotype, which describes the preferred energy pathway to respond to stress. Fresh PBMCs are readily available in the clinical setting using standard phlebotomy. The entire assay described in this protocol can be completed in less than 4 hours without the involvement of complex biochemical techniques. Additionally, we describe a normalization method that is necessary for obtaining reproducible data. The simple procedure and normalization methods presented allow for repeated sample collection from the same patient and generation of reproducible data that can be compared between time points to evaluate potential treatment effects.

Preparation of Novel Homodimers Derived from Cytotoxic Isoquinolinequinones. A Twin Drug Approach

The synthesis of five novel homodimers is reported based on the anilinoisoquinolinequinone scaffold. In these twin-drug derivatives, two units of the anilinoquinone pharmacophores are linked through a methylene spacer. The formation of dimers was achieved by reaction of isoquinolinequinones with 4, 4'-diaminodiphenylmethane via a sequence of two oxidative amination reactions. A preliminary in vitro screening of the homodimers reveals moderate to high cytotoxic activities against MDA-MB-21 breast adenocarcinoma and B16-F10 murine metastatic melanoma cell lines. The asymmetrical homodimer 15 stands out due to its cytotoxic potencies at submicromolar concentrations and high selectivity index (mean IC₅₀ = 0.37 μM; SI = 6.97) compared to those of etoposide (mean IC₅₀ = 3.67; SI = 0.32) and taxol (mean IC₅₀ = 0.35; SI = 0.91) employed as reference anticancer drugs.

Structural essentials for β-N-acetylhexosaminidase inhibition by amides of prolines, pipecolic and azetidine carboxylic acids

This paper explores the computer modelling aided design and synthesis of β-N-acetylhexosaminidase inhibitors along with their applicability to human disease treatment through biological evaluation in both an enzymatic and cellular setting. We investigated the importance of individual stereocenters, variations in structure-activity relationships along with factors influencing cell penetration. To achieve these goals we modified nitrogen heterocycles in terms of ring size, side chains present and ring nitrogen derivatization. By reducing the inhibitor interactions with the active site down to the essentials we were able to determine that besides the established 2S,3R trans-relationship, the presence and stereochemistry of the CH₂OH side chain is of crucial importance for activity. In terms of cellular penetration, N-butyl side chains favour cellar uptake, while hydroxy- and carboxy-group bearing sidechains on the ring nitrogen retarded cellular penetration. Furthermore we show an early proof of principle study that β-N-acetylhexosaminidase inhibitors can be applicable to use in a potential anti-invasive anti-cancer strategy.

Trans10,cis12 conjugated linoleic acid inhibits proliferation and migration of ovarian cancer cells by inducing ER stress, autophagy, and modulation of Src

The goal of this study was to investigate the anti-cancer effects of Trans10,cis12 conjugated linoleic acid (t10,c12 CLA). MTT assays and QCM™ chemotaxis 96-wells were used to test the effect of t10,c12 CLA on the proliferation and migration and invasion of cancer cells. qPCR and Western Blotting were used to determine the expression of specific factors. RNA sequencing was conducted using the Illumina platform and apoptosis was measured using a flow cytometry assay. t10,c12 CLA (IC50, 7 μM) inhibited proliferation of ovarian cancer cell lines SKOV-3 and A2780. c9,t11 CLA did not attenuate the proliferation of these cells. Transcription of 165 genes was significantly repressed and 28 genes were elevated. Genes related to ER stress, ATF4, CHOP, and GADD34 were overexpressed whereas EDEM2 and Hsp90, genes required for proteasomal degradation of misfolded proteins, were downregulated upon treatment. While apoptosis was not detected, t10,c12 CLA treatment led to 9-fold increase in autophagolysosomes and higher levels of LC3-II. G1 cell cycle arrest in treated cells was correlated with phosphorylation of GSK3β and loss of β-catenin. microRNA miR184 and miR215 were upregulated. miR184 likely contributed to G1 arrest by downregulating E2F1. miR215 upregulation was correlated with increased expression of p27/Kip-1. t10,c12 CLA-mediated inhibition of invasion and migration correlated with decreased expression of PTP1b and decreased Src activation by inhibiting phosphorylation at Tyr416. Due to its ability to inhibit proliferation and migration, t10,c12 CLA should be considered for treatment of ovarian cancer.

Polydopamine-collagen complex to enhance the biocompatibility of polydimethylsiloxane substrates for sustaining long-term culture of L929 fibroblasts and tendon stem cells

Polydimethylsiloxane (PDMS) is a commercialized polymer extensively used in the fabrication of versatile microfluidic microdevices for studies in cell biology and tissue engineering. However, the inherent surface hydrophobicity of PDMS is not optimal for cell culture and thus restrains its applications for investigation of long-term behaviors of fibroblasts and stem cells. To improve the surface biocompatibility of PDMS, a facile technique was developed by modifying the PDMS surface with polydopamine-collagen (COL/PDA) complex. The successful synthesis of COL/PDA was verified through proton nuclear magnetic resonance spectroscopy. Compared to surface coating solely with COL or PDA, the surface wettability was significantly improved on COL/PDA-modified PDMS substrates based on water contact angle characterizations. The modified PDMS surface remarkably enhanced the initial adhesion and long-term proliferation of L929 fibroblasts and tendon stem cells (TSCs). Additionally, the effects of COL/PDA coating on cell viability and apoptosis were further investigated under prolonged incubation. We found that the COL/PDA coating on PDMS resulted in a substantial increase of cell viability compared to native PDMS, and the cell apoptosis was considerably impeded on the modified PDMS. This study demonstrated that COL/PDA coating can effectively enhance the surface biocompatibility of PDMS as verified by the enhanced adhesion and long-term proliferation of L929 fibroblasts and TSCs. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 408-418, 2018.

Structure-activity relationships among DNA ligase inhibitors: Characterization of a selective uncompetitive DNA ligase I inhibitor

In human cells, there are three genes that encode DNA ligase polypeptides with distinct but overlapping functions. Previously small molecule inhibitors of human DNA ligases were identified using a structure-based approach. Three of these inhibitors, L82, a DNA ligase I (LigI)-selective inhibitor, and L67, an inhibitor of LigI and DNA ligases III (LigIII), and L189, an inhibitor of all three human DNA ligases, have related structures that are composed of two 6-member aromatic rings separated by different linkers. Here we have performed a structure-activity analysis to identify determinants of activity and selectivity. The majority of the LigI-selective inhibitors had a pyridazine ring whereas the LigI/III- and LigIII-selective inhibitors did not. In addition, the aromatic rings in LigI-selective inhibitors had either arylhydrazone or acylhydrazone, but not vinyl linkers. Among the LigI-selective inhibitors, L82-G17 exhibited increased activity against and selectivity for LigI compared with L82. Notably. L82-G17 is an uncompetitive inhibitor of the third step of the ligation reaction, phosphodiester bond formation. Cells expressing LigI were more sensitive to L82-G17 than isogenic LIG1 null cells. Furthermore, cells lacking nuclear LigIIIα, which can substitute for LigI in DNA replication, were also more sensitive to L82-G17 than isogenic parental cells. Together, our results demonstrate that L82-G17 is a LigI-selective inhibitor with utility as a probe of the catalytic activity and cellular functions of LigI and provide a framework for the future design of DNA ligase inhibitors.