Blue intensity matters for cell cycle profiling in fluorescence DAPI-stained images

Predicting cell cycle stage from 3D single-cell nuclear-stained images

The cell cycle governs the proliferation of all eukaryotic cells. Profiling cell cycle dynamics is therefore central to basic and biomedical research. However, current approaches to cell cycle profiling involve complex interventions that may confound experimental interpretation. We developed CellCycleNet, a machine learning (ML) workflow, to simplify cell cycle staging from fluorescent microscopy data with minimal experimenter intervention and cost. CellCycleNet accurately predicts cell cycle phase using only a fluorescent nuclear stain (DAPI) in fixed interphase cells. Using the Fucci2a cell cycle reporter system as ground truth, we collected two benchmarking image datasets and trained 2D and 3D ML models-of support vector machine and deep neural network architecture-to classify nuclei in the G1 or S/G2 phases. Our results show that 3D CellCycleNet outperforms support vector machine models on each dataset. When trained on two image datasets simultaneously, CellCycleNet achieves the highest classification accuracy (AUROC of 0.94-0.95). Overall, we found that using 3D features, rather than 2D features alone, significantly improves classification performance for all model architectures. We released our image data, models, and software as a community resource.

From Flower to Medicine: Green-Synthesized Silver Nanoparticles as Promising Antibacterial Agents

Background: Breast cancer and chronic bacterial infections are pressing global health issues, and traditional treatments are often hampered by resistance and adverse side effects. This study sought to create silver nanoparticles (AgNPs) through eco-friendly synthesis using Hibiscus rosa sinensis (HRS) flower extract and to assess their antibacterial, antibiofilm, and anticancer properties. Methods: HRS extract functioned as both a reducing and stabilizing agent in the synthesis of AgNPs. The nanoparticles were characterized using ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). Antibacterial and antibiofilm properties were evaluated against gram-positive (Staphylococcus aureus and Enterococcus faecalis) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria using agar well diffusion and XTT reduction assays. The cytotoxic effects on MDMB-231 breast cancer cells and normal splenocytes were measured using the MTT assay, whereas fluorescence microscopy was used to observe reactive oxygen species (ROS) production, changes in mitochondrial membrane potential, and caspase-3 activation. Results: The synthesized HRS-AgNPs, primarily ranging from 10 to 50 nm, displayed a distinct surface plasmon resonance (SPR) peak at 428 nm. They exhibit notable antibacterial activity, especially against gram-positive bacteria, and effectively disrupt bacterial biofilms. Cytotoxicity evaluations showed that HRS-AgNPs decreased the viability of MDMB-231 cells in a dose-dependent manner, with minimal toxicity observed in normal splenocytes. The increase in ROS levels, reduction in mitochondrial membrane potential, and heightened caspase-3 activity collectively suggest apoptosis-driven cell death in cancer cells. Conclusions: HRS-AgNPs demonstrated dual functionality, with strong antibacterial and selective anticancer effects. Their environmentally friendly synthesis, stability, and significant biological activities suggest their potential for further development, including in vivo safety and efficacy assessments for clinical applications in treating infections and breast cancer.

Two types of regenerative cell populations appear in acute liver injury

The liver has a robust regenerative capacity. However, the mechanisms underlying this process remain unclear. Numerous studies on liver regeneration have been previously conducted using partial hepatectomy models, which may not fully represent acute liver injury with inflammation and necrosis. This is commonly observed in the majority of clinical cases. In this study, we conducted a single-cell RNA sequencing (RNA-seq) analysis of liver regeneration in acetaminophen-treated mice using publicly available data. We found that two distinct populations of regenerative cells simultaneously appeared within the same regenerative process. The two populations significantly differed in terms of cell morphology, differentiation, localization, proliferation rate, and signal response. Moreover, one of the populations was induced by contact with necrotic tissue and demonstrated a higher proliferative capacity with a dedifferentiated feature. These findings provide new insights into liver regeneration and therapeutic strategies for liver failure.

Piezoelectric scaffold based on polycaprolactone/thermoplastic polyurethane/barium titanate/cellulose nanocrystal for bone tissue engineering

This study presents the development of a novel piezoelectric scaffold for bone tissue engineering composed of poly(ε-caprolactone) (PCL), thermoplastic polyurethane (TPU), barium titanate (BT), and cellulose nanocrystals (CNC). PCL and TPU are considered advantageous materials because of their ease of processing, versatility in design, and ability to degrade over time; however, their inherent immiscibility poses challenges to achieving optimal porous structures. In this study, porous scaffolds were produced using gas foaming and salt leaching techniques, resulting in highly porous interconnected scaffolds exhibiting considerable elasticity that is suitable for dynamic cell culture while avoiding the use of toxic solvents. Given the piezoelectric nature of bone tissue, incorporating electric biosignals into scaffolds is essential to enhance bone regeneration. Therefore, BT was incorporated as a piezoelectric material. CNC, derived from cotton, assisted in BT distribution and acted as a reinforcing agent, imparting mechanoelectrical signaling properties to the scaffolds. The optimized scaffolds PCL/TPU (75/25) featuring 100 μm pores were integrated with varying BT and CNC ratios and were subjected to multiple analyses. The results showed a measurable electrical output of 1.2 mV and enhanced cell adhesion, viability, and proliferation under dynamic culture conditions, underscoring their potential for bone tissue regeneration.

ProDiVis: a method to normalize fluorescence signal localization in 3D specimens

A common problem in confocal microscopy is the decrease in intensity of excitation light and emission signal from fluorophores as they travel through 3D specimens, resulting in decreased signal detected as a function of depth. Here, we report a visualization program compatible with widely used fluorophores in cell biology to facilitate image interpretation of differential protein disposition in 3D specimens. Glioblastoma cell clusters were fluorescently labeled for mitochondrial complex I (COXI), P2X7 receptor (P2X7R), β-Actin, Ki-67, and DAPI. Each cell cluster was imaged using a laser scanning confocal microscope. We observed up to ∼70% loss in fluorescence signal across the depth in Z-stacks. This progressive underrepresentation of fluorescence intensity as the focal plane deepens hinders an accurate representation of signal location within a 3D structure. To address these challenges, we developed ProDiVis: a program that adjusts apparent fluorescent signals by normalizing one fluorescent signal to a reference signal at each focal plane. ProDiVis serves as a free and accessible, unbiased visualization tool to use in conjunction with fluorescence microscopy images and imaging software.

Predicting cell cycle stage from 3D single-cell nuclear-stained images

The cell cycle governs the proliferation, differentiation, and regeneration of all eukaryotic cells. Profiling cell cycle dynamics is therefore central to basic and biomedical research spanning development, health, aging, and disease. However, current approaches to cell cycle profiling involve complex interventions that may confound experimental interpretation. To facilitate more efficient cell cycle annotation of microscopy data, we developed CellCycleNet, a machine learning (ML) workflow designed to simplify cell cycle staging with minimal experimenter intervention and cost. CellCycleNet accurately predicts cell cycle phase using only a fluorescent nuclear stain (DAPI) in fixed interphase cells. Using the Fucci2a cell cycle reporter system as ground truth, we collected two benchmarking image datasets and trained two ML models-a support vector machine (SVM) and a deep neural network-to classify nuclei as being in either the G1 or S/G2 phases of the cell cycle. Our results suggest that CellCycleNet outperforms state-of-the-art SVM models on each dataset individually. When trained on two image datasets simultaneously, CellCycleNet achieves the highest classification accuracy, with an improvement in AUROC of 0.08-0.09. The model also demonstrates excellent generalization across different microscopes, achieving an AUROC of 0.95. Overall, using features derived from 3D images, rather than 2D projections of those same images, significantly improves classification performance. We have released our image data, trained models, and software as a community resource.

TNBC response to paclitaxel phenocopies interferon response which reveals cell cycle-associated resistance mechanisms

Paclitaxel is a standard of care neoadjuvant therapy for patients with triple negative breast cancer (TNBC); however, it shows limited benefit for locally advanced or metastatic disease. Here we used a coordinated experimental-computational approach to explore the influence of paclitaxel on the cellular and molecular responses of TNBC cells. We found that escalating doses of paclitaxel resulted in multinucleation, promotion of senescence, and initiation of DNA damage induced apoptosis. Single-cell RNA sequencing (scRNA-seq) of TNBC cells after paclitaxel treatment revealed upregulation of innate immune programs canonically associated with interferon response and downregulation of cell cycle progression programs. Systematic exploration of transcriptional responses to paclitaxel and cancer-associated microenvironmental factors revealed common gene programs induced by paclitaxel, IFNB, and IFNG. Transcription factor (TF) enrichment analysis identified 13 TFs that were both enriched based on activity of downstream targets and also significantly upregulated after paclitaxel treatment. Functional assessment with siRNA knockdown confirmed that the TFs FOSL1, NFE2L2 and ELF3 mediate cellular proliferation and also regulate nuclear structure. We further explored the influence of these TFs on paclitaxel-induced cell cycle behavior via live cell imaging, which revealed altered progression rates through G1, S/G2 and M phases. We found that ELF3 knockdown synergized with paclitaxel treatment to lock cells in a G1 state and prevent cell cycle progression. Analysis of publicly available breast cancer patient data showed that high ELF3 expression was associated with poor prognosis and enrichment programs associated with cell cycle progression. Together these analyses disentangle the diverse aspects of paclitaxel response and identify ELF3 upregulation as a putative biomarker of paclitaxel resistance in TNBC.

ARTseq-FISH reveals position-dependent differences in gene expression of micropatterned mESCs

Differences in gene-expression profiles between individual cells can give rise to distinct cell fate decisions. Yet how localisation on a micropattern impacts initial changes in mRNA, protein, and phosphoprotein abundance remains unclear. To identify the effect of cellular position on gene expression, we developed a scalable antibody and mRNA targeting sequential fluorescence in situ hybridisation (ARTseq-FISH) method capable of simultaneously profiling mRNAs, proteins, and phosphoproteins in single cells. We studied 67 (phospho-)protein and mRNA targets in individual mouse embryonic stem cells (mESCs) cultured on circular micropatterns. ARTseq-FISH reveals relative changes in both abundance and localisation of mRNAs and (phospho-)proteins during the first 48 hours of exit from pluripotency. We confirm these changes by conventional immunofluorescence and time-lapse microscopy. Chemical labelling, immunofluorescence, and single-cell time-lapse microscopy further show that cells closer to the edge of the micropattern exhibit increased proliferation compared to cells at the centre. Together these data suggest that while gene expression is still highly heterogeneous position-dependent differences in mRNA and protein levels emerge as early as 12 hours after LIF withdrawal.

Influence of microgravity on spontaneous calcium activity of primary hippocampal neurons grown in microfluidic chips

The influence of variations of gravity, either hypergravity or microgravity, on the brain of astronauts is a major concern for long journeys in space, to the Moon or to Mars, or simply long-duration missions on the ISS (International Space Station). Monitoring brain activity, before and after ISS missions already demonstrated important and long term effects on the brains of astronauts. In this study, we focus on the influence of gravity variations at the cellular level on primary hippocampal neurons. A dedicated setup has been designed and built to perform live calcium imaging during parabolic flights. During a CNES (Centre National d'Etudes Spatiales) parabolic flight campaign, we were able to observe and monitor the calcium activity of 2D networks of neurons inside microfluidic devices during gravity changes over different parabolas. Our preliminary results clearly indicate a modification of the calcium activity associated to variations of gravity.

A semi-automated microscopic image analysis method for scoring Ki-67 nuclear immunostaining

Nuclear proliferation marker MIB-1 (Ki-67) immunohistochemistry (IHC) is used to examine tumor cell proliferation. However, the diagnostic or prognostic value of the Ki-67 nuclear staining intensity and location, defined as nuclear gradient (NG), has not been assessed. This study examined the potential association between Ki-67 NG and cell cycle phases and its effect on the prognosis of pulmonary typical carcinoid (PTC) tumors. We propose a method for classifying the NG of Ki-67 during the cell cycle and compare the results between PTC, pulmonary adenocarcinoma (PAD), and breast ductal carcinoma (BDC). A literature review and objective analysis of IHC-stained paraffin sections were used to determine the Ki-67 labeling index and composed a stratification of the NG into NG1, NG2, and NG3/4 categories. A semi-automated image analysis protocol was established to determine the Ki-67 NG in PTC, PAD, and BDC. High intraobserver consistency and moderate interobserver agreement were achieved in the determination of Ki-67 NG in tumor specimens. NG1 and NG2 were lower in PTC than in PAD and BDC. Cox multivariate analysis of PTC after adjusting for age and number of metastatic lymph nodes showed that Ki-67 NG1 and NG2 significantly predicted clinical outcomes. The semi-automated method for quantification of Ki-67 nuclear immunostaining proposed in this study could become a valuable diagnostic and prognostic tool in PTC.

Polyploidy-associated autophagy promotes larval tracheal histolysis at Drosophila metamorphosis

Polyploidy is an extended phenomenon in biology. However, its physiological significance and whether it defines specific cell behaviors is not well understood. Here we study its connection to macroautophagy/autophagy, using the larval respiratory system of Drosophila as a model. This system comprises cells with the same function yet with notably different ploidy status, namely diploid progenitors and their polyploid larval counterparts, the latter destined to die during metamorphosis. We identified an association between polyploidy and autophagy and found that higher endoreplication status correlates with elevated autophagy. Finally, we report that tissue histolysis in the trachea during Drosophila metamorphosis is mediated by autophagy, which triggers the apoptosis of polyploid cells.Abbreviations: APF: after pupa formation; Atg: autophagy related; btl: breathless; CycE: Cyclin E; DT: dorsal trunk; fzr: fizzy-related; L3: larval stage 3; PBS: phosphate-buffered saline; RI: RNAi; Tr: tracheal metamere; yki: yorkie.

Handling DNA malfunctions by unsupervised machine learning model

The cell cycle is a rich field for research, especially, the DNA damage. DNA damage, which happened naturally or as a result of environmental influences causes change in the chemical structure of DNA. The extent of DNA damage has a significant impact on the fate of the cell in later stages. In this paper, we introduced an Unsupervised Machine learning Model for DNA Damage Diagnosis and Analysis. Mainly, we employed K-means clustering unsupervised machine learning algorithms. Unsupervised algorithms commonly draw conclusions from datasets by solely utilizing input vectors, disregarding any known or labeled outcomes. The model provided deep insight about DNA damage and exposes the protein levels for proteins when work together in sub-network model to deal with DNA damage occurrence, the unsupervised artificial model explained the sub-network biological model activities in regard to the changing in their concentrations in several clusters, they have been grouped in such as (0 - no damage, 1 - low, 2 - medium, 3 - high, and 4 - excess) DNA damage clusters. The results provided a rational and persuasive explanation for numerous important phenomena, including the oscillation of the protein p53, in a clear and understandable manner. Which is encouraging since it demonstrates that the K-means clustering approach can be easily applied to many similar biological systems, which aids in better understanding the key dynamics of these systems.

High throughput microscopy and single cell phenotypic image-based analysis in toxicology and drug discovery

Measuring single cell responses to the universe of chemicals (drugs, natural products, environmental toxicants etc.) is of paramount importance to human health as phenotypic variability in sensing stimuli is a hallmark of biology that is considered during high throughput screening. One of the ways to approach this problem is via high throughput, microscopy-based assays coupled with multi-dimensional single cell analysis methods. Here, we will summarize some of the efforts in this vast and growing field, focusing on phenotypic screens (e.g., Cell Painting), single cell analytics and quality control, with particular attention to environmental toxicology and drug screening. We will discuss advantages and limitations of high throughput assays with various end points and levels of complexity.

ADAD1 is required for normal translation of nuclear pore and transport protein transcripts in spermatids of Mus musculus†

ADAD1 is a testis-specific RNA-binding protein expressed in post-meiotic spermatids whose loss leads to defective sperm and male infertility. However, the drivers of the Adad1 phenotype remain unclear. Morphological and functional analysis of Adad1 mutant sperm showed defective DNA compaction, abnormal head shaping, and reduced motility. Mutant testes demonstrated minimal transcriptome changes; however, ribosome association of many transcripts was reduced, suggesting ADAD1 may be required for their translational activation. Further, immunofluorescence of proteins encoded by select transcripts showed delayed protein accumulation. Additional analyses demonstrated impaired subcellular localization of multiple proteins, suggesting protein transport is also abnormal in Adad1 mutants. To clarify the mechanism giving rise to this, the manchette, a protein transport microtubule network, and the LINC (linker of nucleoskeleton and cytoskeleton) complex, which connects the manchette to the nuclear lamin, were assessed across spermatid development. Proteins of both displayed delayed translation and/or localization in mutant spermatids implicating ADAD1 in their regulation, even in the absence of altered ribosome association. Finally, ADAD1's impact on the NPC (nuclear pore complex), a regulator of both the manchette and the LINC complex, was examined. Reduced ribosome association of NPC encoding transcripts and reduced NPC protein abundance along with abnormal localization in Adad1 mutants confirmed ADAD1's impact on translation is required for a NPC in post-meiotic germ cells. Together, these studies lead to a model whereby ADAD1's influence on nuclear transport leads to deregulation of the LINC complex and the manchette, ultimately generating the range of physiological defects observed in the Adad1 phenotype.

Evaluating single-cell variability in proteasomal decay

Gene expression is a stochastic process that leads to variability in mRNA and protein abundances even within an isogenic population of cells grown in the same environment. This variation, often called gene-expression noise, has typically been attributed to transcriptional and translational processes while ignoring the contributions of protein decay variability across cells. Here we estimate the single-cell protein decay rates of two degron GFPs in Saccharomyces cerevisiae using time-lapse microscopy. We find substantial cell-to-cell variability in the decay rates of the degron GFPs. We evaluate cellular features that explain the variability in the proteasomal decay and find that the amount of 20s catalytic beta subunit of the proteasome marginally explains the observed variability in the degron GFP half-lives. We propose alternate hypotheses that might explain the observed variability in the decay of the two degron GFPs. Overall, our study highlights the importance of studying the kinetics of the decay process at single-cell resolution and that decay rates vary at the single-cell level, and that the decay process is stochastic. A complex model of decay dynamics must be included when modeling stochastic gene expression to estimate gene expression noise.

Lacticaseibacillus rhamnosus—A Promising Tool for Colorectal Cancer Treatment

Probiotic strains such as Lactobacillus spp. are already known for their beneficial effect on human health and new research supports their role in colon cancer prevention and treatment. The current study reports the effect of different concentrations of Lacticaseibacillus rhamnosus (LGG, 106–109 CFU/mL), alone or in association with 5-fluorouracil (5-FU, 10 μM), tested against normal HaCaT cells, HT-29 colorectal adenocarcinoma and HCT-116 colorectal carcinoma cell lines. The underlying cytotoxic effect was further investigated. LGG treatment of HT-29 and HCT-116 cells caused a variety of apoptotic-related nuclear morphological changes, as revealed by DAPI staining. ELISA studies showed that LGG treatment increased caspase-3 activity and pro-apoptotic BAX protein levels while decreasing anti-apoptotic Bcl-2 protein levels and the proto-oncogene Cyclin D1. A more detailed examination of the mitochondrial function revealed that high concentrations of LGG can impair mitochondrial function in HT-29 and HCT-116 cancer cells. All of these findings suggest that LGG has a pro-apoptotic, mitochondrial-targeted, cytotoxic effect on both colon cancer cell lines studied.

Interpreting Image-based Profiles using Similarity Clustering and Single-Cell Visualization

Image-based profiling quantitatively assesses the effects of perturbations on cells by capturing a breadth of changes via microscopy. Here, we provide two complementary protocols to help explore and interpret data from image-based profiling experiments. In the first protocol, we examine the similarity among perturbed cell samples using data from compounds that cluster by their mechanisms of action. The protocol includes steps to examine feature-driving differences between samples and to visualize correlations between features and treatments to create interpretable heatmaps using the open-source web tool Morpheus. In the second protocol, we show how to interactively explore images together with the numerical data, and we provide scripts to create visualizations of representative single cells and image sites to understand how changes in features are reflected in the images. Together, these two tutorials help researchers interpret image-based data to speed up research. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Exploratory analysis of profile similarities and driving features Basic Protocol 2: Image and single-cell visualization following profile interpretation.

Liver Ultrasound Histotripsy: Novel Analysis of the Histotripsy Site Cell Constituents with Implications for Histotripsy Application in Cell Transplantation and Cancer Therapy

Introduction: Allogenic hepatocyte transplantation is an attractive alternative to whole-organ transplantation, particularly for the treatment of metabolic disorders and acute liver failure. However, the shortage of human donor organs for cell isolation, the low cell yield from decellularisation regimes, and low engraftment rates from portal administration of donor cells have restricted its clinical application. Using ultrasound histotripsy to provide a nidus in the liver for direct cell transplantation offers a new approach to overcoming key limitations in current cell therapy. We have analysed the liver cavity constituents to assess their potential as a site for cell delivery and implantation. Methods: Using human organ retrieval techniques, pig livers were collected from the abattoir and transported in ice-cold storage to the laboratory. Following 2 h of cold storage, the livers were flushed with organ preservation solution and placed on an organ perfusion circuit to maintain viability. Organs were perfused with Soltran™ organ preservation solution via the portal vein at a temperature of 24-30 °C. The perfusion circuit was oxygenated through equilibration with room air. Perfused livers (n=5) were subjected to ultrasound histotripsy, producing a total of 130 lesions. Lesions were generated by applying 50 pulses at 1 Hz pulse repetition frequency and 1% duty cycle using a single element 2 MHz bowl-shaped transducer (Sonic Concepts, H-148). Following histotripsy, a focal liver lesion was produced, which had a liquid centre. The fluid from each lesion was aspirated and cultured in medium (RPMI) at 37 °C in an incubator. Cell cultures were analysed at 1 and 7 days for cell viability and a live-dead assay was performed. The histotripsy sites were excised following aspiration and H&E staining was used to characterise the liver lesions. Cell morphology was determined by histology. Results: Histotripsy created a subcapsular lesion (~5 mm below the liver capsule; size ranging from 3 to 5 mm), which contained a suspension of cells. On average, 61×10⁴ cells per mL were isolated. Hepatocytes were present in the aspirate, were viable at 24 h post isolation and remained viable in culture for up to 1 week, as determined by phalloidin/DAPI cell viability stains. Cultures up to 21 days revealed metabolically active live hepatocyte. Live-dead assays confirmed hepatocyte viability at 1 week (Day 1: 12% to Day 7: 45% live cells; p < 0.0001), which retained metabolic activity and morphology, confirmed on assay and microscopy. Cell Titre-Glo^TM showed a peak metabolic activity at 1 week (average luminescence 24.6 RLU; p < 0.0001) post-culture compared with the control (culture medium alone), reduced to 1/3 of peak level (7.85 RLU) by day 21. Conclusions: Histotripsy of the liver allows isolation and culture of hepatocytes with a high rate of viability after 1 week in culture. Reproducing these findings using human livers may lead to wide clinical applications in cell therapy.

Indole-3-carbinol induces apoptosis in AGS cancer cells via mitochondrial pathway

Indole-3-carbinol is produced from the cruciferous vegetables and broadly investigated for their various biological effects in in-vitro and in-vivo aspects. However, the anticancer activity of I3C and its molecular mechanisms have not been investigated in human adeno gastro carcinoma (AGS) cells. In our study of AGS cells, nuclear condensation was observed by 4',6-diamidino-2-phenylindole (DAPI) staining, cell death was confirmed by a cell viability assay, and fragmented DNA was observed at the IC₅₀ dose by a DNA fragmentation assay. Apoptosis was evaluated by the qPCR technique. Treatment of the AGS cells with I3C at different concentrations has drastically decreased cell proliferation and differentiation. By releasing cytochrome-c from mitochondria in the intrinsic pathway, I3C prevents the multiplication of AGS cells and initiates apoptosis. The WST-1 assay result showed that I3C treatment against AGS cells had considerably reduced the viability of the cells. Furthermore, RT-qPCR showed the fold change among the expressed proteins compared with reference gene β-actin. Molecular docking revealed that I3C showed a strong binding affinity for the apoptotic protein 3DCY. The results show the caspase group of proteins contribute to the core of apoptotic machinery. I3C and its metabolites target a variety of components of cell-cycle control via distinct signaling pathways in light of the rapid development of tumors and oncogenesis. The translational significance of I3C and its metabolites in cancer is highlighted by their wide range of antitumor activity and low toxicity. Furthermore, the novel prodrug I3C, which has overlapping underlying mechanisms, could encourage new strategies to decrease oncogenesis.

Adipose Tissue-Derived Extracellular Vesicles Contribute to Phenotypic Plasticity of Prostate Cancer Cells

Metastatic prostate cancer is one of the leading causes of male cancer deaths in the western world. Obesity significantly increases the risk of metastatic disease and is associated with a higher mortality rate. Systemic chronic inflammation can result from a variety of conditions, including obesity, where adipose tissue inflammation is a major contributor. Adipose tissue endothelial cells (EC) exposed to inflammation become dysfunctional and produce a secretome, including extracellular vesicles (EV), that can impact function of cells in distant tissues, including malignant cells. The aim of this study was to explore the potential role of EVs produced by obese adipose tissue and the ECs exposed to pro-inflammatory cytokines on prostate cancer phenotypic plasticity in vitro. We demonstrate that PC3ML metastatic prostate cancer cells exposed to EVs from adipose tissue ECs and to EVs from human adipose tissue total explants display reduced invasion and increased proliferation. The latter functional changes could be attributed to the EV miRNA cargo. We also show that the functional shift is TWIST1-dependent and is consistent with mesenchymal-to-epithelial transition, which is key to establishment of secondary tumor growth. Understanding the complex effects of EVs on prostate cancer cells of different phenotypes is key before their intended use as therapeutics.

Epigenetic Changes in Saccharomyces cerevisiae Alters the Aromatic Profile in Alcoholic Fermentation

Epigenetic changes in genomics provide phenotypic modification without DNA sequence alteration. This study shows that benzoic acid, a common food additive and known histone deacetylase inhibitor (HDACi), has an epigenetic effect on Saccharomyces cerevisiae. Benzoic acid stimulated formation of epigenetic histone marks H3K4Me2, H3K27Me2, H3K18ac, and H3Ser10p in S. cerevisiae and altered their phenotypic behavior, resulting in increased production of phenylethyl alcohol and ester compounds during alcoholic fermentation using wine as a representative model system. Our study demonstrates the HDACi activity of certain dietary compounds such as sodium butyrate, curcumin and anacardic acid, suggests the potential use of these dietary compounds in altering S. cerevisiae phenotypes without altering host-cell DNA. This study highlights the potential to use common dietary compounds to exploit epigenetic modifications for various fermentation and biotechnology applications as an alternative to genetic modification. These findings indicate that benzoic acid and other food additives may have potential epigenetic effects on human gut microbiota, in which several yeast species are involved. IMPORTANCE The manuscript investigates and reports for the first time utilizing a non-GMO approach to alter the fermentation process of Pinot Noir wines. We have experimentally demonstrated that certain dietary compounds possess histone deacetylase (HDAC) inhibiting activity and can alter the wine characteristics by potentially altering yeast gene transcription, which was resulted from epigenetic effects. We have previously proposed the term "nutrifermentics" to represent this newly proposed field of research that provides insights on the effect of certain dietary compounds on microbial strains and their potential application in fermentation. This technological approach is a novel way to manipulate microorganisms for innovative food and beverage production with quality attributes catering for consumer's needs. Using a multidisciplinary approach with an emphasis on food fermentation and biotechnology, this study will be substantially useful and of broad interest to food microbiologists and biotechnologists who seek for innovative concepts with real-world application potential.

The Use of Yeast in Biosensing

Yeast has been used as a model for several diseases as it is the simplest unicellular eukaryote, safe and easy to culture and harbors most of the fundamental processes that are present in almost all higher eukaryotes, including humans. From understanding the pathogenesis of disease to drug discovery studies, yeast has served as an important biosensor. It is not only due to the conservation of genetics, amenable modification of its genome and easily accessible analytical methods, but also some characteristic features such as its ability to survive with defective mitochondria, making it a highly flexible microbe for designing whole-cell biosensing systems. The aim of this review is to report on how yeasts have been utilized as biosensors, reporting on responses to various stimuli.

Proposal for a New Diagnostic Histopathological Approach in the Evaluation of Ki-67 in GEP-NETs

Introduction: Studies have shown that the Ki-67 index is a valuable biomarker for the diagnosis, and classification of gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs). We re-evaluated the expression of Ki-67 based on the intensity of the stain, basing our hypothesis on the fact that the Ki-67 protein is continuously degraded. Background: The aim was to evaluate whether a new scoring method would be more effective in classifying NETs by reducing staining heterogeneity. Methods: Patients with GEP-NET (n = 87) were analyzed. The classification difference between the two methods was determined. Results: The classification changed significantly when the Ki-67 semiquantal index was used. The percentage of G1 patients increased from 18.4% to 60.9%, while the G2 patients decreased from 66.7% to 29.9% and the G3 patients also decreased from 14.9% to 9.2%. Moreover, it was found that the traditional Ki-67 was not significantly related to the overall survival (OS), whereas the semiquantal Ki-67 was significantly related to the OS. Conclusions: The new quantification was a better predictor of OS and of tumor classification. Therefore, it could be used both as a marker of proliferation and as a tool to map tumor dynamics that can influence the diagnosis and guide the choice of therapy.

Development of a G2/M arrest high-throughput screening method identifies potent radiosensitizers

Radiation is a powerful tool used to control tumor growth and induce an immune response; however, it is limited by damage to surrounding tissue and adverse effects such skin irritation. Breast cancer patients in particular may endure radiation dermatitis, and potentially lymphedema, after a course of radiotherapy. Radio-sensitizing small molecule drugs may enable lower effective doses of both radiation and chemotherapy to minimize toxicity to healthy tissue. In this study, we identified a novel high-throughput method for screening radiosensitizers by image analysis of nuclear size and cell cycle. In vitro assays were performed on cancer cells lines to assess combined therapeutic and radiation effects. In vivo, radiation in combination with proflavine hemisulfate led to enhanced efficacy demonstrated by improved tumor volume control in mice bearing syngeneic breast tumors. This study provides a proof of concept for utilizing G2/M stall as a predictor of radiosensitization and is the first report of a flavin acting as an X-ray radiation enhancer in a breast cancer mouse model.

A Proximity Ligation Method to Detect Proteins Bound to Single-Stranded DNA after DNA End Resection at DNA Double-Strand Breaks

After a DNA double-strand break, cells utilize either non-homologous end joining or homologous recombination to repair the broken DNA ends. Homologous recombination requires extensive nucleolytic processing of one of the DNA strands, resulting in long stretches of 3′ single-strand DNA overhangs. Typically, single-stranded DNA is measured using immunofluorescence microscopy to image the foci of replication protein A, a single-stranded DNA-binding protein. Microscopy analysis of bromodeoxyuridine foci under nondenaturing conditions has also been used to measure single-stranded DNA. Here, we describe a proximity ligation assay which uses genome-wide bromodeoxyuridine incorporation to label single-stranded DNA in order to measure the association of a protein of interest with single-stranded DNA. This method is advantageous over traditional foci analysis because it is more direct and specific than traditional foci co-localization microscopy methods, uses only one color channel, and can reveal protein-single-stranded DNA interactions that are rare and potentially undetectable using traditional microscopy methods. We show here the association of replication protein A and bromodeoxyuridine as proof-of-concept.

Curcumin nano-micelle induced testicular toxicity in healthy rats; evidence for oxidative stress and failed homeostatic response by heat shock proteins 70-2a and 90

This study explores the effect of curcumin nano-micelle (NCMN) on the testicular anti-oxidant status and heat shock proteins (Hsp) 70-2a and Hsp 90 expression. Therefore, 24 male Wistar rats were divided into control, 7.50 mg/kg, 15 mg/kg, and 30 mg/kg of NCMN-received groups. Following 48 days, the testicular total anti-oxidant capacity (TAC), total oxidant status (TOS), malondialdehyde (MDA) and glutathione (GSH), catalase (CAT) and glutathione peroxidase (GPX) activities, immunoreactivity of 8-oxodG, Hsp70-2a and Hsp90 expressions, germ cell's DNA and mRNA damages, the spermatozoa count, motility and DNA integrity were assessed. With no change in the testicular TAC level, the TOS, MDA and GSH contents were increased in the NMC-received groups. However, CAT and GPX activities were decreased. The NCMN suppressed spermatogenesis, increased immunoreactivity of 8-oxodG, stimulated the Hsp70-2a and Hsp90 expressions, and resulted in severe DNA and mRNA damages. Moreover, the NCMN-received animals exhibited remarkable reductions in the spermatozoa count, motility and DNA integrity. In conclusion, chronic and high dose consumption of NCMN initiates OS, and in response to OS, the Hsp70-2a and Hsp90 expression increases. However, considering enhanced DNA and mRNA damages and suppressed spermatogenesis, HSPs over-expression can neither boost the anti-oxidant system nor overcome the NCMN-induced OS-related damages.

Lockdown of mitochondrial Ca2+ extrusion and subsequent resveratrol treatment kill HeLa cells by Ca2+ overload

Anticancer effect of resveratrol and the role of sodium/lithium/calcium exchanger in context with calcium ions are studied in human cervical cancer cell line. This therapeutic approach using siNCLX mediated gene silencing and drug therapy with resveratrol indicates the disruption of calcium homeostasis, increase in caspase (-3, 8, 9) mRNA expressions and DNA damage leading to apoptotic cell death. Monitoring the intracellular Ca2+ changes using fluo-4AM indicates highest rise in [Ca2+] level in sodium/lithium/calcium exchanger silenced group with five different stages, that is distinguishable based on the fluorescence intensity. In resveratrol treated and siNCLX + resveratrol treated groups no such cell staging differences were observed, despite uniform Ca2+ rise followed by decrease in the intensity. Integrating RNAi gene silencing of sodium/lithium/calcium exchanger with resveratrol can form the most interesting, efficient and promising therapeutic strategy in the treatment of cancer.

A machine learning approach for single cell interphase cell cycle staging

The cell nucleus is a tightly regulated organelle and its architectural structure is dynamically orchestrated to maintain normal cell function. Indeed, fluctuations in nuclear size and shape are known to occur during the cell cycle and alterations in nuclear morphology are also hallmarks of many diseases including cancer. Regrettably, automated reliable tools for cell cycle staging at single cell level using in situ images are still limited. It is therefore urgent to establish accurate strategies combining bioimaging with high-content image analysis for a bona fide classification. In this study we developed a supervised machine learning method for interphase cell cycle staging of individual adherent cells using in situ fluorescence images of nuclei stained with DAPI. A Support Vector Machine (SVM) classifier operated over normalized nuclear features using more than 3500 DAPI stained nuclei. Molecular ground truth labels were obtained by automatic image processing using fluorescent ubiquitination-based cell cycle indicator (Fucci) technology. An average F1-Score of 87.7% was achieved with this framework. Furthermore, the method was validated on distinct cell types reaching recall values higher than 89%. Our method is a robust approach to identify cells in G₁ or S/G₂ at the individual level, with implications in research and clinical applications.

Synthesis, characterization of ruthenium(II), nickel(II), palladium(II), and platinum(II) triphenylphosphine-based complexes bearing an ONS-donor chelating agent: Interaction with biomolecules, antioxidant, in vitro cytotoxic, apoptotic activity and cell cycle analysis

Four new transition metal complexes, [M(PPh₃)(L)]^.CH₃OH (M = Ni(II) (1), Pd(II) (2)) [Pt (PPh₃)₂(HL)]Cl (3) and [Ru(CO)(PPh₃)₂(L)] (4) (H₂L = 2,4-dihydroxybenzaldehyde-S-methyldithiocarbazate, PPh₃ = triphenylphosphine) have been synthesized and characterized by elemental analyses (C, H, N), FTIR, NMR (¹H, ³¹P), ESI-MS and UV-visible spectroscopy. The molecular structure of (1) and (2) complexes was confirmed by single-crystal X-ray crystallography. It showed a distorted square planar geometry for both complexes around the metal center, and the H₂L adopt a bi-negative tridentate chelating mode. The interaction with biomolecules viz., calf thymus DNA (ct DNA), yeast RNA (tRNA), and BSA (bovine serum albumin) was examined by both UV-visible and fluorescence spectroscopies. The antioxidant activity of all compounds is discussed on basis of DPPH^• (2,2-diphenyl-1-picrylhydrazyl) scavenging activity and showed better antioxidant activity for complexes compared to the ligand. The in vitro cytotoxicity of the compounds was tested on human (breast cancer (MCF7), colon cancer (HCT116), liver cancer (HepG2), and normal lung fibroblast (WI38)) cell lines, showing that complex (1) the most potent against MCF7 and complex (4) against HCT116 cell lines based on IC₅₀ and selective indices (SI) values. So, both complexes were chosen for further studies such as DNA fragmentation, cell apoptosis, and cell cycle analyses. Complex (1) induced MCF7 cell death by cellular apoptosis and arrest cells at S phase. Complex (4) induced HCT116 cell death predominantly by cellular necrosis and arrested cell division at G2/M phase due to DNA damage.

An Imbalanced Image Classification Method for the Cell Cycle Phase

The cell cycle is an important process in cellular life. In recent years, some image processing methods have been developed to determine the cell cycle stages of individual cells. However, in most of these methods, cells have to be segmented, and their features need to be extracted. During feature extraction, some important information may be lost, resulting in lower classification accuracy. Thus, we used a deep learning method to retain all cell features. In order to solve the problems surrounding insufficient numbers of original images and the imbalanced distribution of original images, we used the Wasserstein generative adversarial network-gradient penalty (WGAN-GP) for data augmentation. At the same time, a residual network (ResNet) was used for image classification. ResNet is one of the most used deep learning classification networks. The classification accuracy of cell cycle images was achieved more effectively with our method, reaching 83.88%. Compared with an accuracy of 79.40% in previous experiments, our accuracy increased by 4.48%. Another dataset was used to verify the effect of our model and, compared with the accuracy from previous results, our accuracy increased by 12.52%. The results showed that our new cell cycle image classification system based on WGAN-GP and ResNet is useful for the classification of imbalanced images. Moreover, our method could potentially solve the low classification accuracy in biomedical images caused by insufficient numbers of original images and the imbalanced distribution of original images.

BG-flow, a new flow cytometry tool for G-quadruplex quantification in fixed cells

BACKGROUND

Nucleic acids can fold into non-canonical secondary structures named G-quadruplexes (G4s), which consist of guanine-rich sequences stacked into guanine tetrads stabilized by Hoogsteen hydrogen bonding, π-π interactions, and monovalent cations. G4 structure formation and properties are well established in vitro, but potential in vivo functions remain controversial. G4s are evolutionarily enriched at distinct, functional genomic loci, and both genetic and molecular findings indicate that G4s are involved in multiple aspects of cellular homeostasis. In order to gain a deeper understanding of the function of G4 structures and the trigger signals for their formation, robust biochemical methods are needed to detect and quantify G4 structures in living cells. Currently available methods mostly rely on fluorescence microscopy or deep sequencing of immunoprecipitated DNA or RNA using G4-specific antibodies. These methods provide a clear picture of the cellular or genomic localization of G4 structures but are very time-consuming. Here, we assembled a novel protocol that uses the G4-specific antibody BG4 to quantify G4 structures by flow cytometry (BG-flow).

RESULTS

We describe and validate a flow cytometry-based protocol for quantifying G4 levels by using the G4-specific antibody BG4 to label standard cultured cells (Hela and THP-1) as well as primary cells obtained from human blood (peripheral blood mononuclear cells (PBMCs)). We additionally determined changes in G4 levels during the cell cycle in immortalized MCF-7 cells, and validated changes previously observed in G4 levels by treating mouse macrophages with the G4-stabilizing agent pyridostatin (PDS).

CONCLUSION

We provide mechanistic proof that BG-flow is working in different kinds of cells ranging from mouse to humans. We propose that BG-flow can be combined with additional antibodies for cell surface markers to determine G4 structures in subpopulations of cells, which will be beneficial to address the relevance and consequences of G4 structures in mixed cell populations. This will support ongoing research that discusses G4 structures as a novel diagnostic tool.

A novel evaluation method for Ki-67 immunostaining in paraffin-embedded tissues

The Ki-67 labeling index is traditionally used to investigate tumor aggressiveness. However, no diagnostic or prognostic value has been associated to the heterogeneous pattern of nuclear positivity. The aims of this study were to develop a classification for the patterns of Ki-67-positive nuclei; to search scientific evidence for the Ki-67 expression and location throughout the cell cycle; and to develop a protocol to apply the classification of patterns of Ki-67-positive nuclei in squamous epithelium with different proliferative activities. Based on empirical observation of paraffin sections submitted to immunohistochemistry for the determination of Ki-67 labeling index and literature review about Ki-67 expression, we created a classification of the patterns of nuclear positivity (NP1, NP2, NP3, NP4, and mitosis). A semi-automatic protocol was developed to identify and quantify the Ki-67 immunostaining patterns in target tissues. Two observers evaluated 7000 nuclei twice to test the intraobserver reliability, and six evaluated 1000 nuclei to the interobserver evaluation. The results showed that the immunohistochemical patterns of Ki-67 are similar in the tumoral and non-tumoral epithelium and were classified without difficulty. There was a high intraobserver reliability (Spearman correlation coefficient > 0.9) and moderate interobserver agreement (k = 0.523). Statistical analysis showed that non-malignant epithelial specimens presented a higher number of NP1 (geographic tongue = 83.8 ± 21.8; no lesion = 107.6 ± 52.7; and mild dysplasia = 86.6 ± 25.8) when compared to carcinoma in Situ (46.8 ± 34.8) and invasive carcinoma (72.6 ± 37.9). The statistical evaluation showed significant difference (p < 0.05). Thus, we propose a new way to evaluate Ki-67, where the pattern of its expression may be associated with the dynamics of the cell cycle. Future proof of this association will validate the use of the classification for its possible impact on cancer prognosis and guidance on personalized therapy.

Cell-to-cell and genome-to-genome variability of adenovirus transcription tuned by the cell cycle

In clonal cultures, not all cells are equally susceptible to virus infection, and the mechanisms underlying this are poorly understood. Here, we developed image-based single-cell measurements to scrutinize the heterogeneity of adenovirus (AdV) infection. AdV delivers, transcribes and replicates a linear double-stranded DNA genome in the nucleus. We measured the abundance of viral transcripts using single-molecule RNA fluorescence in situ hybridization (FISH) and the incoming 5-ethynyl-2'-deoxycytidine (EdC)-tagged viral genomes using a copper(I)-catalyzed azide-alkyne cycloaddition (click) reaction. Surprisingly, expression of the immediate early gene E1A only moderately correlated with the number of viral genomes in the cell nucleus. Intranuclear genome-to-genome heterogeneity was found at the level of viral transcription and, in accordance, individual genomes exhibited heterogeneous replication activity. By analyzing the cell cycle state, we found that G1 cells exhibited the highest E1A gene expression and displayed increased correlation between E1A gene expression and viral genome copy numbers. The combined image-based single-molecule procedures described here are ideally suited to explore the cell-to-cell variability in viral gene expression in a range of different settings, including the innate immune response.

Combining Deep Learning with Handcrafted Features for Cell Nuclei Segmentation

Segmentation of cell nuclei in fluorescence microscopy images provides valuable information about the shape and size of the nuclei, its chromatin texture and DNA content. It has many applications such as cell tracking, counting and classification. In this work, we extended our recently proposed approach for nuclei segmentation based on deep learning, by adding to its input handcrafted features. Our handcrafted features introduce additional domain knowledge that nuclei are expected to have an approximately round shape. For round shapes the gradient vector of points at the border point to the center. To convey this information, we compute a map of gradient convergence to be used by the CNN as a new channel, in addition to the fluorescence microscopy image. We applied our method to a dataset of microscopy images of cells stained with DAPI. Our results show that with this approach we are able to decrease the number of missdetections and, therefore, increase the F1-Score when compared to our previously proposed approach. Moreover, the results show that faster convergence is obtained when handcrafted features are combined with deep learning.

Interphase Cell Cycle Staging using Deep Learning. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020;2020:1432-1435. [PMID: 33018259 DOI: 10.1109/embc44109.2020.9175583]

The progression of cells through the cell cycle is a tightly regulated process and is known to be key in maintaining normal tissue architecture and function. Disruption of these orchestrated phases will result in alterations that can lead to many diseases including cancer. Regrettably, reliable automatic tools to evaluate the cell cycle stage of individual cells are still lacking, in particular at interphase. Therefore, the development of new tools for a proper classification are urgently needed and will be of critical importance for cancer prognosis and predictive therapeutic purposes. Thus, in this work, we aimed to investigate three deep learning approaches for interphase cell cycle staging in microscopy images: 1) joint detection and cell cycle classification of nuclei patches; 2) detection of cell nuclei patches followed by classification of the cycle stage; 3) detection and segmentation of cell nuclei followed by classification of cell cycle staging. Our methods were applied to a dataset of microscopy images of nuclei stained with DAPI. The best results (0.908 F1-Score) were obtained with approach 3 in which the segmentation step allows for an intensity normalization that takes into account the intensities of all nuclei in a given image. These results show that for a correct cell cycle staging it is important to consider the relative intensities of the nuclei. Herein, we have developed a new deep learning method for interphase cell cycle staging at single cell level with potential implications in cancer prognosis and therapeutic strategies.

High-content fluorescence imaging with the metabolic flux assay reveals insights into mitochondrial properties and functions

Metabolic flux technology with the Seahorse bioanalyzer has emerged as a standard technique in cellular metabolism studies, allowing for simultaneous kinetic measurements of respiration and glycolysis. Methods to extend the utility and versatility of the metabolic flux assay would undoubtedly have immediate and wide-reaching impacts. Herein, we describe a platform that couples the metabolic flux assay with high-content fluorescence imaging to simultaneously provide means for normalization of respiration data with cell number; analyze cell cycle distribution; and quantify mitochondrial content, fragmentation state, membrane potential, and mitochondrial reactive oxygen species. Integration of fluorescent dyes directly into the metabolic flux assay generates a more complete data set of mitochondrial features in a single assay. Moreover, application of this integrated strategy revealed insights into mitochondrial function following PGC1a and PRC1 inhibition in pancreatic cancer and demonstrated how the Rho-GTPases impact mitochondrial dynamics in breast cancer.

Underlying mechanisms of apoptosis in HepG2 cells induced by polyphyllin I through Fas death and mitochondrial pathways

Aims: Polyphyllin I, a steroidal saponin in Rhizoma paridis, which possess broad application prospects in cancer prevention and treatment. The purpose of this study was to determine the potential cytotoxicity and mechanism of Polyphyllin I in HepG2 cells.Main methods: In this study, we used MTT to evaluate cell survival. Cell apoptosis rate, cell cycle distribution, mitochondrial membrane potential and ros levels were measured by flow cytometry, and the expression of apoptosis-related proteins was determined by Western blot analysis.Key findings: Polyphyllin I significantly reduced cell viability and induced HepG2 cell apoptosis in a dose and time-dependent manner. Compared with the control group, it could induce reactive oxygen species (ROS) generation and depolarization of matrix metalloproteinases in liver cells. Polyphyllin I dose-dependent increased the release of mitochondrial cytochrome c, and levels of Fas, p53, p21, and Bax/Bcl-2 ratios, as well as the activation of cleaved caspase-3, -8, -9, and subsequent cleavage of the poly (ADP-ribose) polymerase (PARP). The G2/M phase cell cycle arrest was induced by increasing the expression of p21 and cyclin E1, and significantly reducing the expression of cyclin A2 and CDK2.Significance: Our results suggested that Polyphylin I inhibited cell proliferation and growth by triggering G2/M cell cycle arrest, and induced apoptosis through intracellular and extracellular apoptosis pathways to cause cell death by generating reactive oxygen species.

Non-destructive, label free identification of cell cycle phase in cancer cells by multispectral microscopy of autofluorescence

Background

Cell cycle analysis is important for cancer research. However, available methodologies have drawbacks including limited categorisation and reliance on fixation, staining or transformation. Multispectral analysis of endogenous cell autofluorescence has been shown to be sensitive to changes in cell status and could be applied to the discrimination of cell cycle without these steps.

Methods

Cells from the MIA-PaCa-2, PANC-1, and HeLa cell lines were plated on gridded dishes and imaged using a multispectral fluorescence microscope. They were then stained for proliferating cell nuclear antigen (PCNA) and DNA intensity as a reference standard for their cell cycle position (G1, S, G2, M). The multispectral data was split into training and testing datasets and models were generated to discriminate between G1, S, and G2 + M phase cells. A standard decision tree classification approach was taken, and a two-step system was generated for each line.

Results

Across cancer cell lines accuracy ranged from 68.3% (MIA-PaCa-2) to 73.3% (HeLa) for distinguishing G1 from S and G2 + M, and 69.0% (MIA-PaCa-2) to 78.0% (PANC1) for distinguishing S from G2 + M. Unmixing the multispectral data showed that the autofluorophores NADH, FAD, and PPIX had significant differences between phases. Similarly, the redox ratio and the ratio of protein bound to free NADH were significantly affected.

Conclusions

These results demonstrate that multispectral microscopy could be used for the non-destructive, label free discrimination of cell cycle phase in cancer cells. They provide novel information on the mechanisms of cell-cycle progression and control, and have practical implications for oncology research.

Matrine Exerts Hepatotoxic Effects via the ROS-Dependent Mitochondrial Apoptosis Pathway and Inhibition of Nrf2-Mediated Antioxidant Response

Matrine, an alkaloid isolated from Sophora flavescens, possesses a wide range of pharmacological properties. However, the use of matrine in clinical practice is limited due to its toxic effects. The present study investigated the roles of mitochondria and reactive oxygen species (ROS) in matrine-induced liver injury. Our results showed that treatment of HL-7702 cells with matrine led to significant and concentration- and time-dependent reductions in their viability, as well as significant and concentration-dependent increases in the number of apoptotic cells and supernatant lactate dehydrogenase (LDH) activity. The treatment led to significant increases in the population of cells in S phase and significant reduction of cell proportion in G0/G1 and G2/M phases. It also significantly and concentration-dependently increased the levels of ROS and malondialdehyde (MDA) but significantly and concentration-dependently reduced superoxide dismutase (SOD) activity, level of reduced glutathione (GSH), and mitochondrial membrane potential (MMP). Matrine treatment significantly and concentration-dependently upregulated the expressions of Bax, p53, p-p53, p21, cyclin E, Fas, cleaved caspase-3, caspase-8, and caspase-9 proteins and downregulated the expressions of Bcl-2, cyclin-dependent kinase 2 (CDK2), and cyclin A. It also significantly promoted the cleavage of poly(ADP-ribose)polymerase (PARP), upregulated Kelch-like ECH-associated protein 1 (Keap1) expression, and downregulated the expressions of cellular total and nuclear Nrf2. Matrine significantly inhibited the expressions of downstream oxidoreductases (Heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductases 1 (NQO-1)) and enhanced the formation of Keap1/Nrf2 protein complex. These results show that the hepatotoxic effect of matrine is exerted via inhibition of Nrf2 pathway, activation of ROS-mediated mitochondrial apoptosis pathway, and cell cycle arrest at S phase. Pretreatment with N-acetyl cysteine (NAC) partially reversed matrine-induced hepatotoxicity.

Aloe arborescens juice prevents EMF-induced oxidative stress and thus protects from pathophysiology in the male reproductive system in vitro

More and more studies suggest that prolonged exposure to EMF may cause adverse biological effects and point directly to a significantly negative correlation between EMF and human health, especially men fertility. In our previous study, we reported that this could be related to the EMF-induced reactive oxygen species formation, followed by DNA damage, cell cycle arrest and apoptosis induction. In this study, we decided to expand our research by the search for substances which would prevent EMF-induced damage in spermatogenic cells. Such an agent seems to be Aloe arborescens Mill. juice, which was shown to possess a wide range of protective properties. The administration of aloe extract helps among others to prevent the formation of free radicals by various biochemical pathways. Therefore, the main aim of our study was to provide a significant knowledge concerning the mechanism involved in the multi-pathway cytoprotective response of aloe juice against EMF. The study was carried out in an in vitro mouse spermatogenesis pathway cell lines (GC-1 spg and GC-2 spd). Our results suggest that the aloe juice has many positive effects, especially for the cellular antioxidant systems by reducing the intracellular reactive oxygen species pool induced by EMF. In consequence, aloe juice prevents DNA damage, cell cycle arrest and therefore the viability and metabolic activity of both cell line tested are preserved. In conclusion, our study provides new insight into the underlying mechanisms through which aloe juice prevents spermatogenic cells from cytotoxic and genotoxic events.

Multiparameter Phenotypic Profiling in MCF-7 Cells for Assessing the Toxicity and Estrogenic Activity of Whole Environmental Water

Multi-parameter phenotypic profiling of small molecules is a powerful approach to their toxicity assessment and identifying potential mechanisms of actions. The present study demonstrates the application of image-based multi-parameter phenotypic profiling in MCF-7 cells to assess the overall toxicity and estrogenic activity of whole environmental water. Phenotypic profiling of 30 reference compounds and their complex mixtures was evaluated to investigate the cellular morphological outcomes to targeted biological pathways. Overall toxicity and estrogenic activity of environmental water samples were then evaluated by phenotypic analysis comparing with conventional bioassays and chemical analysis by multivariate analysis. The phenotypic analysis for reference compounds demonstrated that size and structure of cells related to biological processes like cell growth, death, and communication. The phenotypic alteration and nuclei intensity were selected as potential biomarkers to evaluate overall toxicity and estrogenic activities, respectively. The phenotypic profiles were associated with the chemical structure profiles in environmental water samples. Since the phenotypic parameters revealed multiple toxicity endpoints, it could provide more information that is relevant to assessing the toxicity of environmental water samples in compare with conventional bioassays. In conclusion, the image-based multi-parameters phenotypic analysis with MCF-7 cells provides a rapid and information-rich tool for toxicity evaluation and identification in whole water samples.

Triptolide Induces Apoptosis Through Fas Death and Mitochondrial Pathways in HepaRG Cell Line

Triptolide isolated from the traditional Chinese herb Tripterygium wilfordii Hook F., possesses anti-tumor, anti-fertility, and anti-inflammatory properties. Triptolide-induced hepatotoxicity has continued to engage the attention of researchers. However, not much is yet known about the cytotoxicity of triptolide, and the precise mechanisms involved. In the present study, we investigated the cytotoxicity of triptolide and its underlying mechanisms, using the in vitro model (HepaRG cell). The results demonstrated that triptolide significantly reduced cell viability and induced apoptosis in HepaRG cells in a dose- and time-dependent manner. Triptolide treatment also provoked reactive oxygen species (ROS) generation and depolarization of mitochondrial membrane potential (MMP). Moreover, triptolide dose-dependently increased the protein expression levels of Fas, Bax, p53, p21, cyclin E, cleaved caspase-3, 8, and 9; and subsequent cleavage of poly (ADP-ribose) polymerase (PARP). However, the protein expression of Bcl-2, cyclin A, and CDK 2 were significantly decreased. These results suggest that triptolide inhibits cell proliferation and induces apoptosis via the Fas death pathway and the mitochondrial pathway.