Detection Of DNA Damage Research Articles

The variant senescence-associated secretory phenotype induced by centrosome amplification constitutes a pathway that activates hypoxia-inducible factor-1α.

The senescence-associated secretory phenotype (SASP) can promote paracrine invasion while suppressing tumour growth, thus generating complex phenotypic outcomes. Likewise, centrosome amplification can induce proliferation arrest yet also facilitate tumour invasion. However, the eventual fate of cells with centrosome amplification remains elusive. Here, we report that centrosome amplification induces a variant of SASP, which constitutes a pathway activating paracrine invasion. The centrosome amplification-induced SASP is non-canonical as it lacks the archetypal detectable DNA damage and prominent NF-κB activation, but involves Rac activation and production of reactive oxygen species. Consequently, it induces hypoxia-inducible factor 1α and associated genes, including pro-migratory factors such as ANGPTL4. Of note, cellular senescence can either induce tumourigenesis through paracrine signalling or conversely suppress tumourigenesis through p53 induction. By analogy, centrosome amplification-induced SASP may therefore be one reason why extra centrosomes promote malignancy in some experimental models but are neutral in others.

DNA Damage Response Alterations in Ovarian Cancer: From Molecular Mechanisms to Therapeutic Opportunities.

The DNA damage response (DDR), a set of signaling pathways for DNA damage detection and repair, maintains genomic stability when cells are exposed to endogenous or exogenous DNA-damaging agents. Alterations in these pathways are strongly associated with cancer development, including ovarian cancer (OC), the most lethal gynecologic malignancy. In OC, failures in the DDR have been related not only to the onset but also to progression and chemoresistance. It is known that approximately half of the most frequent subtype, high-grade serous carcinoma (HGSC), exhibit defects in DNA double-strand break (DSB) repair by homologous recombination (HR), and current evidence indicates that probably all HGSCs harbor a defect in at least one DDR pathway. These defects are not restricted to HGSCs; mutations in ARID1A, which are present in 30% of endometrioid OCs and 50% of clear cell (CC) carcinomas, have also been found to confer deficiencies in DNA repair. Moreover, DDR alterations have been described in a variable percentage of the different OC subtypes. Here, we overview the main DNA repair pathways involved in the maintenance of genome stability and their deregulation in OC. We also recapitulate the preclinical and clinical data supporting the potential of targeting the DDR to fight the disease.

EOAI, a ubiquitin-specific peptidase 5 inhibitor, prevents non-small cell lung cancer progression by inducing DNA damage

ObjectiveTargeting deubiquitinases (DUBs) has emerged as a promising avenue for anticancer drug development. However, the effect and mechanism of pan-DUB inhibitor EOAI on non-small cell lung cancer (NSCLC) remains to be studied.Materials and methodsThe expression of ubiquitin-specific peptidase 5 (USP5) in NSCLC was evaluated by immunohistochemistry. The effect of the USP5 inhibitor, EOAI, on NSCLC cell growth and cell cycle was evaluated by CCK-8 and PI staining. Apoptosis was detected by Annexin V-FITC/PI double staining. Autophagy was examined by LC3 immunofluorescence. Comet assay and γ-H2AX immunofluorescence staining were used to detect DNA damage, and Western blotting was used to detect the expression of apoptosis, cycle, autophagy and DNA damage-related proteins. In vivo experiments demonstrated the effect of EOAI on NSCLC.ResultsWe also found that USP5 was significantly upregulated in NSCLC tissues in this study. In addition, we show that EOAI can cause DNA damage in NSCLC cells while modulating the transcriptional activity of P53, thereby inducing cell cycle arrest in NSCLC cells, autophagy and apoptosis. In vivo experiments have shown that EOAI can inhibit tumors and synergistically enhance the anti-tumor effect of cisplatin.ConclusionUSP5-mediated epigenetic regulation of oncogenes promotes the occurrence of NSCLC, which provides ideas for developing potential targeted therapy.

Surface plasmon resonance detection of UV irradiation-induced DNA damage and photoenzymatic repair processes through specific interaction between consensus double-stranded DNA and p53 protein.

DNA damage, such as DNA lesions and strand breaks, impairs normal cell functions and failure in the DNA repair process could lead to gene mutation, cell apoptosis and disease occurrence. p53 is a tumor suppressor and DNA-binding protein, and DNA damage might affect their interaction and the subsequent p53 function. Herein, real-time monitoring of DNA damage and repair processes through DNA-p53 protein interaction was performed by surface plasmon resonance (SPR). The target DNA with consecutive pyrimidine nucleobases was first damaged upon UVC (254 nm) irradiation and then photoenzymatically repaired under UVA (365 nm) irradiation. The as-formed double-stranded (ds) DNA between probe DNA and normal, damaged or repaired target DNA was immobilized on the sensor chips, followed by the injection of p53 protein. By measuring the SPR signals under different cases, the DNA damage and repair processes could be conveniently monitored. The SPR signals were inversely proportional to the UVC doses ranging from 0.021 to 1.26 kJ m-2, providing a viable means for the quantification of the DNA damage level. The binding affinity between p53 and the dsDNA formed upon the hybridization of probe DNA and normal, damaged, or photoenzymatically repaired target DNA was estimated. This is the first report on measuring the equilibrium dissociation constant (KD) between the p53 protein and the dsDNA with photodamaged or repaired target sequences. The sensing strategy by SPR thus opens a new avenue for real-time measurement of the DNA damage and the repair processes.

Genotoxic effects of oxyclozanide on hemocytes of Galleria mellonella (Lepidoptera: Pyralidae) larvae

Oxyclozanide is a salicylanilide derivative anthelmintic drug with a well-known effect on parasites that cause infections in humans and animals. In this study, the effect of oxyclozanide on DNA damage in hemocytes of Galleria mellonella (L.) (Lepidoptera: Pyralidae) larvae, which has been used as a model organism in many fields, was investigated. Hemolymph was collected from the last instar larvae (7th instar) reared on artificial diets containing oxyclozanide at different concentrations (0.003%, 0.03%, 0.3%, and 1.5%) under laboratory conditions and then hemocytes suspension was prepared. Genotoxic damage in hemocytes was determined by the comet assay which enables microscopically detecting DNA damage and is a very sensitive assay in chemical genotoxicity. When compared to the control group, tail length, tail DNA percent, and tail moment values were significantly increased parallel with increasing oxyclozanide concentrations. While the tail length was determined as 5.11 ± 0.46 μm in the control group, it was significantly increased in all tested groups to 13.17 ± 0.53, 27.98 ± 1.08, 98.44 ± 0.77, and 137.67 ± 0.74 μm, respectively. Similarly to tail length, tail DNA percentage and tail moment levels were also significantly increased from 12.86 ± 0.74 to 91.96 ± 0.31 at the highest concentration of oxyclozanide. These results showed that oxyclozanide caused DNA damage in the hemocytes of G. mellonella. It is also known that hemocytes are an important bioindicator in determining the genotoxicity of anthelmintics to be used as insecticides within environmentally friendly limits. It is thought that our results will contribute to the studies in this field.

Anti-Cancer Effects of Trigonella foenum in Neuroblastoma Cell Line

Objective: Current approaches focus on the use of natural compounds in plants in the treatment of cancer. Trigonella foenum (Fenugreek) is mainly used in medicine, food, and cosmetics due to its bioactive and aromatic compounds. Many compounds with medicinal effects are found in Fenugreek seeds. These compounds have been demonstrated to be effective on numerous cancer cells. Neuroblastoma is one of the most common extracranial solid malignancies in children. In our study, the effects of Fenugreek on cell cytotoxicity, cell damage, migration, and sphere formation in neuroblastoma cells were investigated. Materials and Methods: The powder extract was dissolved in DMEM and filtered to prepare a stock solution of Fenugreek. We used MTT assay for the detection of cytotoxic effects of Fenugreek on SH-SY5Y cells, crystal violet staining for the analysis of morphological change in cells, wound healing test for the cell migration analysis, and agarose gel electrophoresis for detecting DNA damage. We created a spheroid to test the effect we observed in 2D culture, in 3D culture as well. Results: The findings of our study showed that Fenugreek treatments caused significant reductions in cell proliferation and migration capacities in 2D neuroblastoma cells at IC50 (1500 μg/ml) doses, respectively. In addition Fenugreek changed cell morphology and increased DNA fragmentation. Furthermore, Fenugreek caused disruption of 3D spheroid formation of SHSY-5Y cells in a dose- and time-dependent manner. Conclusion: The determination of the anti-cancer effect of Fenugreek on neuroblastoma cancer may be a useful and feasible intervention in neuroblastoma patients in the light of further studies and with the help of new nano drug delivery systems.

Estimation of DNA damage in the roots of Allium cepa exposed to heavy metals using comet assay

Higher plants were used as a bioindicator of environmental toxicity to estimate the severe problems related to the health of living organisms and the environment. Allium cepa plant was used to evaluate the DNA damage caused by heavy metal exposure, the roots of A.cepa plant. They were treated with four concentrations (5, 10, 20 and 25 ppm) for each of the metals Cadmium, zinc, copper and lead. At the same time, concentrations (50, 100, 200 and 500 ppm) were used for the preservative (sodium benzoate). The comet assay, a sensitive and suitable test for assessing DNA damage caused by chemical exposure, was used in this study. The Comet's six characteristics were measured: Head intensity, Head DNA%, Tail length, Tail intensity, Tail DNA% and Tail moment. The results showed that the metals are causing the DNA damage of meristematic cells of the roots of the A. cepa plant, depending on the tail length from most to least effective Cadmium> zinc > sodium benzoate > copper > lead > wastewater. I consider that it is not necessary to write down these values. The results of this study confirm that the meristematic cells of the roots of A. cepa are a suitable model for detecting DNA damage analyzed by the comet assay. Keywords: Toxic metals - Bio-indicator - Single cell gel electrophoresis (SCGE)

A Scalable 3D High-Content Imaging Protocol for Measuring a Drug Induced DNA Damage Response Using Immunofluorescent Subnuclear γH2AX Spots in Patient Derived Ovarian Cancer Organoids.

The high morbidity rate of ovarian cancer has remained unchanged during the past four decades, partly due to a lack of understanding of disease mechanisms and difficulties in developing new targeted therapies. Defective DNA damage detection and repair is one of the hallmarks of cancer cells and is a defining characteristic of ovarian cancer. Most in vitro studies to date involve viability measurements at scale using relevant cancer cell lines; however, the translation to the clinic is often lacking. The use of patient derived organoids is closing that translational gap, yet the 3D nature of organoid cultures presents challenges for assay measurements beyond viability measurements. In particular, high-content imaging has the potential for screening at scale, providing a better understanding of the mechanism of action of drugs or genetic perturbagens. In this study we report a semiautomated and scalable immunofluorescence imaging assay utilizing the development of a 384-well plate based subnuclear staining and clearing protocol and optimization of 3D confocal image analysis for studying DNA damage dose response in human ovarian cancer organoids. The assay was validated in four organoid models and demonstrated a predictable response to etoposide drug treatment with the lowest efficacy observed in the clinically most resistant model. This imaging and analysis method can be applied to other 3D organoid and spheroid models for use in high content screening.

Determination of Ram (Ovis aries) Sperm DNA Damage Due to Oxidative Stress: 8-OHdG Immunodetection Assay vs. SCSA®.

Conventional DNA analysis techniques can hardly detect DNA damage in ruminant spermatozoa due to high DNA compaction in these cells. Furthermore, these techniques cannot discriminate whether the damage is due to oxidative stress. The main purpose of this study was to evaluate the efficacy of two techniques for determining DNA damage in ovine sperm when the source of that damage is oxidative stress. Semen samples from twenty Manchega rams (Ovis aries) were collected and cryopreserved. After thawing, the samples were subjected to different levels of oxidative stress, and DNA oxidation was quantified using an 8-hydroxy-2′-deoxyguanosine (8-OHdG) immunodetection assay and Sperm Chromatin Structure Assay (SCSA®). For this purpose, we evaluated five different concentrations of an oxidation solution (H2O2/FeSO4•7H2O) on ram sperm DNA. Our study with the 8-OHdG immunodetection assay shows that there are higher values for DNA oxidation in samples that were subjected to the highest oxidative stress (8 M H2O2/800 µM FeSO4•7H2O) and those that were not exposed to high oxidative stress, but these differences were not significant (p ≥ 0.05). The two SCSA® parameters considered, DNA fragmentation index (DFI %) and high DNA stainability (HDS %), showed significant differences between samples that were subjected to high concentrations of the oxidation agent and those that were not (p < 0.05). We can conclude that the 8-OHdG immunodetection assay and SCSA® detect DNA damage caused by oxidative stress in ovine sperm under high oxidative conditions; SCSA® is a more straightforward method with more accurate results. For these reasons, an oxidative-stress-specific assay such as 8-OHdG immunodetection is not needed to measure DNA damage caused by oxidative stress in ram sperm samples.

Esophageal Squamous Cancer from 4NQO-Induced Mice Model: CNV Alterations.

Squamous esophageal carcinoma is a common pathological type of esophageal carcinoma around the world. The prognosis of esophageal carcinoma is usually poor and diagnosed at late stages. Recently, research suggested that genomic instability occurred in esophageal cells during the development of esophageal squamous cell carcinoma (ESCC). Identifying prognostic and specific genomic characteristics, especially at the early hyperplasia stage, is critical. Mice were given 4-nitroquinoline 1-oxide (4NQO) with drinking water to induce esophageal cancer. The immortalized human esophageal epithelial cell line (NE2) was also treated with 4NQO. We performed histologic analyses, immunofluorescence, and immunohistochemical staining to detect DNA damage at different time points. Whole-exome sequencing was accomplished on the esophagus tissues at different pathological stages to detect single-nucleotide variants and copy number variation (CNV) in the genome. Our findings indicate that all mice were tumor-forming, and a series of changes from simple hyperplasia (ESSH) to intraepithelial neoplasia (IEN) to esophageal squamous cell carcinoma (ESCC) was seen at different times. The expression of γ-H2AX increased from ESSH to ESCC. In addition, mutations of the Muc4 gene were detected throughout the pathological stages. Furthermore, CNV burden appeared in the esophageal tissues from the beginning of ESSH and accumulated more in cancer with the deepening of the lesions. This study demonstrates that mutations caused by the early appearance of DNA damage may appear in the early stage of malignant tissue before the emergence of atypia. The detection of CNV and mutations of the Muc4 gene may be used as an ultra-early screening indicator for esophageal cancer.

Xiao-Xu-Ming decoction extracts promotes mitochondrial biogenesis and improves neurobehavioral deficits in cerebral ischemia/reperfusion rats

Introduction: Stroke is one of the leading causes of death and disability in the worldwide. Traditional Chinese medicine plays an important role in preventing and treatment of stroke. Xiao-Xu-Ming decoction (XXM) is an effective traditional Chinese prescription for the treatment of stroke and its sequelae. Previous studies have reported the extracts of XXM has a good therapeutic effect on experimental animal stroke. However, the mechanism is unclear. Our present study focused on metabolic remodeling in cerebral ischemia-reperfusion to investigate the mechanism of XXM on cerebral ischemia/reperfusion (I/R). Methods: The cerebral I/R rat model was established by 90 min middle cerebral artery occlusion following reperfusion. XXM at doses of 37.5, 75 and 150 mg/kg was administered for the continuous 7 day after cerebral I/R. Behavioral testing, cerebral infarction detected by TTC staining, Nissl staining, NeuN immunohistochemical staining, and MAP2 immunofluorescence staining were conducted to evaluate the effect of XXM treatment on cerebral I/R of rats. TUNEL staining was used to detect DNA damage. The expression of related proteins was detected by qPCR and western blotting. Results: 7 day XXM treatment improved neurological and behavioral deficits, regulated the biogenesis and dynamic process of mitochondria, promoted the recovery of mitochondrial function, and improved the energy metabolism disorder after cerebral I/R. Furthermore, XXM also had an improving effect on mitochondrial-dependent apoptosis after cerebral I/R. Conclusion: we found that XXM regulated metabolic remodeling in cerebral ischemia-reperfusion and improve neurological deficits.

Detecting DNA damage in stored blood samples

Several commercially available quantitative real-time PCR (qPCR) systems enable highly sensitive detection of human DNA and provide a degradation index (DI) to assess DNA quality. From routine casework in forensic genetics, it was observed that DNA degradation in forensic samples such as blood samples stored under sub-optimal conditions leads to visible effects in multiplex analyses of short tandem repeat markers (STRs) due to decreased amplification efficiencies in longer amplicons. It was further noticed that degradation indices often remain below the value that is considered to be critical. Thus, the aim of this work was to systematically analyze this effect and to compare conventional qPCR assays with a modified qPCR approach using uracil DNA glycosylase (UNG) and DNA quality assessment methods based on electrophoresis. Blood samples were stored at three different storage temperatures for up to 316 days. Significantly increased DNA recovery was observed from samples stored at high temperatures (37 °C) compared samples stored at room temperature and 4 °C. We observed typical effects of degradation in STR analyses but no correlation between DI and storage time in any of the storage conditions. Adding UNG slightly increased the sensitivity of detecting DNA degradation in one of the qPCR kits used in this study. This observation was not confirmed when using a second qPCR system. Electrophoretic systems did also not reveal significant correlations between integrity values and time. Methods for detecting DNA degradation are usually limited to the detection of DNA fragmentation, and we conclude that degradation affecting forensic STR typing is more complex.

Detection and Quantitation of DNA Damage on a Genome-wide Scale Using RADAR-seq.

The formation and persistence of DNA damage can impact biological processes such as DNA replication and transcription. To maintain genome stability and integrity, organisms rely on robust DNA damage repair pathways. Techniques to detect and locate DNA damage sites across a genome enable an understanding of the consequences of DNA damage as well as how damage is repaired, which can have key diagnostic and therapeutic implications. Importantly, advancements in technology have enabled the development of high-throughput sequencing-based DNA damage detection methods. These methods require DNA enrichment or amplification steps that limit the ability to quantitate the DNA damage sites. Further, each of these methods is typically tailored to detect only a specific type of damage. RAre DAmage and Repair (RADAR) sequencing is a DNA sequencing workflow that overcomes these limitations and enables detection and quantitation of DNA damage sites in any organism on a genome-wide scale. RADAR-seq works by replacing DNA damage sites with a patch of modified bases that can be directly detected by Pacific Biosciences Single-Molecule Real Time sequencing. Here, we present three protocols that enable detection of thymine dimers and ribonucleotides in bacterial and archaeal genomes. Basic Protocol 1 enables construction of a reference genome required for RADAR-seq analyses. Basic Protocol 2 describes how to locate, quantitate, and compare thymine dimer levels in Escherichia coli exposed to varying amounts of UV light. Basic Protocol 3 describes how to locate, quantitate, and compare ribonucleotide levels in wild-type and ΔRNaseH2 Thermococcus kodakarensis. Importantly, all three protocols provide in-depth steps for data analysis. Together they serve as proof-of-principle experiments that will allow users to adapt the protocols to locate and quantitate a wide variety of DNA damage sites in any organism. © 2022 New England Biolabs. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Constructing a reference genome utilizing SMRT sequencing Basic Protocol 2: Mapping and quantitating genomic thymine dimer formation in untreated versus UV-irradiated E. coli using RADAR-seq Basic Protocol 3: Mapping and quantitating genomic ribonucleotide incorporation in wildtype versus ΔRNaseH2 T. kodakarensis using RADAR-seq.

Revealing low-temperature plasma efficacy through a dose-rate assessment by DNA damage detection combined with machine learning models

Low-temperature plasmas have quickly emerged as alternative and unconventional types of radiation that offer great promise for various clinical modalities. As with other types of radiation, the therapeutic efficacy and safety of low-temperature plasmas are ubiquitous concerns, and assessing their dose rates is crucial in clinical settings. Unfortunately, assessing the dose rates by standard dosimetric techniques has been challenging. To overcome this difficulty, we proposed a dose-rate assessment framework that combined the predictive modeling of plasma-induced damage in DNA by machine learning with existing radiation dose-DNA damage correlations. Our results indicated that low-temperature plasmas have a remarkably high dose rate that can be tuned by various process parameters. This attribute is beneficial for inducing radiobiological effects in a more controllable manner.

EMS-induced cellular DNA damage detection by electrochemical method: A new biomarker of early DNA damage

It is difficult to screen the increasing numerous chemicals in the environment for DNA damage by traditional methods. Therefore, it is urgent to find new markers and establish simple, rapid and low-cost new DNA damage detection methods. In this paper, the electrochemical behavior of Ethyl methanesulfonate (EMS)-induced DNA damage in HT-1080 cells was investigated, and the two electrochemical signals of HT-1080 cells at 0.69 and 1.03 V, respectively, coming from mixture of guanine (G) and xanthine (X) and hypoxanthine (HX) displayed parabolic changes, showing a time- and dose-dependent increase within 4 h and 5 mM, which was completely different from the trend of cell proliferation. The time- and dose-dependent DNA damage of cells exposed to EMS was detected by both alkaline comet and micronucleus assay. The HPLC found that the levels of HX, G and X in HT-1080 cells quickly rose to the peak values within 4 h, and felt back. The changes of intracellular purine levels were reliable biomarkers of DNA damage, and monitoring the content changes of intracellular purines by electrochemical method could simply and quickly evaluate the DNA damage toxicity of chemicals. This study provided a new perspective for the evaluation of DNA damage.

COMET Assay for Detection of DNA Damage During Axolotl Tail Regeneration.

The purpose of this chapter is to evaluate DNA damage during axolotl tail regeneration using an alkaline comet assay. Our method details the isolation of cells from regenerating and non-regenerating tissues and the isolation of peripheral blood for single-cell gel electrophoresis. Also, we detail each of the steps for the development of the comet assay technique which includes mounting the isolated cells on an agarose matrix, alkaline electrophoresis, and DNA damage detection.

A Principal Approach to the Detection of Radiation-Induced DNA Damage by Circular Dichroism Spectroscopy and Its Dosimetric Application

Using cholesteric liquid-crystalline dispersion (CLCD) of DNA, we demonstrate that the molecularly organized systems may be used both for qualitative assessment of the degree of radiation-induced DNA damage, as well as for detection of radiation doses in a very wide range. The doses up to 500 Gy do not cause any significant changes in optical signals of DNA in solution. However, when irradiated molecules are used to prepare the CLCD by addition of crowding polymer, a clear correlation of its optical signals with an absorbed dose is observed. For example, at a dose of 500 Gy, a maximum drop in the circular dichroism (CD) signal for DNA solution and for CLCD formed from preliminary irradiated molecules is ≈20% and ≈700%, respectively. This approach can also be used to expand the dosimetric capabilities of DNA CLCD. Compared to the case of irradiation of ready-made DNA CLCD, formation of the dispersed system from irradiated DNA allows to increase its sensitivity by more than 2 orders of magnitude. A similar decrease in the CD signal (≈1.45-fold) is observed in these systems at the doses of 100 kGy and 200 Gy, respectively. This principal approach seems to be relevant for other biomolecules and molecularly organized systems.

Detection of DNA Damage in Hematopoietic Stem Cells.

Single-cell gel electrophoresis (SCGE or Comet assay) and the Fast Halo assay, also known as the Halo assay, are powerful tools to generate DNA damage measurements with single-cell resolution. Though these techniques are prone to have variability, they can be robust tools for quantifying DNA damage when planned and executed carefully. Here, we present both assays and highlight each technique's advantages and challenges in measuring DNA damage in cells with limiting cell number, such as hematopoietic stem cells (HSCs). The Comet assay is highly sensitive at the cost of increased variability. The Halo assay attenuates some of the effects of variability present in the Comet assay but does not eliminate them entirely and is less sensitive. Overall, the Comet and Halo assays are powerful means of directly measuring DNA damage. We recommend the below methods for detecting damage in hematopoietic stem cells, but the methods can easily be adjusted for measuring damage in any type of single cells in suspension.

CISS-Based Label-Free Novel Electrochemical Impedimetric Detection of UVC-Induced DNA Damage.

In this work, we demonstrate chiral-induced spin selectivity (CISS)-based label-free electrochemical impedimetric detection of radiation-induced DNA damage using the electrons’ spin as a novel tool of sensing. For this, self-assembled monolayers (SAMs) of short ds-DNA (of length 7.14 nm) are prepared on arrays of multilayer thin film devices comprising a gold overlay (500 μm diameter with 10 nm thickness) on a nickel thin film (100 nm) fabricated by the physical vapor deposition technique. Subsequently, the SAMs of ds-DNA are exposed to ultraviolet C (UVC) radiation for a prolonged period of 8 h to induce structural perturbations in DNA. The susceptibility of DNA to radiation-induced damage was probed by recording the spin-dependent electrochemical impedimetric spectra, wherein a continuous sinusoidal wave of the amplitude of 10 mV was superimposed on DC bias in the frequency range of 100–105 Hz, with simultaneous spin injection through the attached DNA. The inherent correlation between the charge-transfer resistance (Rct) and the spin selectivity of electrons through DNA was taken into account for the detection of DNA damage for the first time with a limit of detection achieved up to 10 picomolar concentrations of DNA. As the spin-polarized electrons directly probe the structural symmetry, it is robust against perturbation from electronic signals usually found in conventional electrochemical biosensors.

2-Methoxyestradiol Damages DNA in Glioblastoma Cells by Regulating nNOS and Heat Shock Proteins

Gliomas are the most prevalent primary tumors of the central nervous system (CNS), accounting for over fifty percent of all primary intracranial neoplasms. Glioblastoma (GBM) is the most prevalent form of malignant glioma and is often incurable. The main distinguishing trait of GBM is the presence of hypoxic regions accompanied by enhanced angiogenesis. 2-Methoxyestradiol (2-ME) is a well-established antiangiogenic and antiproliferative drug. In current clinical studies, 2-ME, known as Panzem, was examined for breast, ovarian, prostate, and multiple myeloma. The SW1088 grade III glioma cell line was treated with pharmacological and physiological doses of 2-ME. The induction of apoptosis and necrosis, oxidative stress, cell cycle arrest, and mitochondrial membrane potential were established by flow cytometry. Confocal microscopy was used to detect DNA damage. The Western blot technique determined the level of nitric oxide synthase and heat shock proteins. Here, for the first time, 2-ME is shown to induce nitro-oxidative stress with the concomitant modulation of heat shock proteins (HSPs) in the SW1088 grade III glioma cell line. Crucial therapeutic strategies for GMB should address both cell proliferation and angiogenesis, and due to the above, 2-ME seems to be a perfect candidate for GBM therapy.