scholarly journals Development of an In Vitro whole cell Micronucleus Multiplex expansion assay: Using DRAQ5™ and the DNA damage biomarkers ɣH2AX, P53, pH3 along with cell cycle relationships and the MN genotoxic endpoint to assess chemical Mode of Action on an imaging flow cytometry platform with template development

2021 ◽  
Author(s):  
◽  
Danielle S.G. Harte
Keyword(s):  
Cell Cycle ◽  
Flow Cytometry ◽  
Dna Damage ◽  
Mode Of Action ◽  
In Vitro Tests ◽  
Genetic Toxicology ◽  
Whole Cell ◽  
Imaging Flow Cytometry ◽  
Multiplex System

Genetic toxicity testing is the assessment of compounds, and their respective metabolites, potential to cause DNA damage either directly or indirectly. There are many genetic toxicology screening assays designed to assess the DNA damaging potential of chemicals in early drug development to help identify promising drugs that have a low risk potential of causing damage leading to cancer in humans. Despite this, in vitro tests generate a high number of miss-leading positives, the consequences of which lead to unnecessary animal testing and abandoning promising drug candidates. Understanding chemical Mode of Action (MoA) is vital in identifying true genotoxic potential of substances. Here I demonstrate a simple robust protocol for optimised staining of fixed human lymphoblast P53 proficient TK6 cells with the antibodies; Anti-ɣH2AX, Anti-P53 and Ant-pH3S28 along with DRAQ5™ DNA staining in a whole cell multiplex system that is suitable for analysis via microscopy or imaging flow cytometry. Use of the Amnis FlowSight® and ImageStream X Mark II® platform provided a high content high throughput acquisition platform with the sensitivity of flow cytometry and accuracy of image analysis. Using both optimal and suboptimal lasers for fluorophore excitation demonstrated that a multiplex system for DNA damage assessment including MN was possible in un-lysed cells. IDEAS 6.2 template generation allowed for batch processing of data samples extracting the following metrics: Cell Cycle, Micronucleus (MN), ɣH2AX, P53, PH3, G1 ɣH2AX, G1 P53, S ɣH2AX, S P53, G2 ɣH2AX, G2/M P53, Prophase, Metaphase, Anaphase and Abnormal mitosis. Furthermore, high content nature of the platform using imagery allows for identification of rare cellular event assessment particularly preliminary data on biomarker signal found within MN. The system found differences in the biomarker metric responses between the chemicals; MMS, Carbendazim, ARA-C, Vinblastine, Etoposide and Crizotinib suggesting potential for chemical MoA elucidation.

A Novel Camptothecin Derivative 3j Inhibits Nsclc Proliferation Via Induction of Cell Cycle Arrest By Topo I-Mediated DNA Damage

2019 ◽  
Vol 19 (3) ◽  
pp. 365-374 ◽  
Author(s):  
Yang Liu ◽  
Jingyin Zhang ◽  
Shuyun Feng ◽  
Tingli Zhao ◽  
Zhengzheng Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Flow Cytometry ◽  
Dna Damage ◽  
Cyclin D ◽  
Dna Relaxation ◽  
Cycle Arrest ◽  
H460 Cell ◽  
H1975 Cell

Objective: The aim of this study is to investigate the inhibitory effect of camptothecin derivative 3j on Non-Small Cell Lung Cancer (NSCLCs) cells and the potential anti-tumor mechanisms. Background: Camptothecin compounds are considered as the third largest natural drugs which are widely investigated in the world and they suffered restriction because of serious toxicity, such as hemorrhagic cystitis and bone marrow suppression. Methods: Using cell proliferation assay and S180 tumor mice model, a series of 20(S)-O-substituted benzoyl 7- ethylcamptothecin compounds were screened and evaluated the antitumor activities in vitro and in vivo. Camptothecin derivative 3j was selected for further study using flow cytometry in NSCLCs cells. Cell cycle related protein cyclin A2, CDK2, cyclin D and cyclin E were detected by Western Blot. Then, computer molecular docking was used to confirm the interaction between 3j and Topo I. Also, DNA relaxation assay and alkaline comet assay were used to investigate the mechanism of 3j on DNA damage. Results: Our results demonstrated that camptothecin derivative 3j showed a greater antitumor effect in eleven 20(S)-O-substituted benzoyl 7-ethylcamptothecin compounds in vitro and in vivo. The IC50 of 3j was 1.54± 0.41 µM lower than irinotecan with an IC50 of 13.86±0.80 µM in NCI-H460 cell, which was reduced by 8 fold. In NCI-H1975 cell, the IC50 of 3j was 1.87±0.23 µM lower than irinotecan (IC50±SD, 5.35±0.38 µM), dropped by 1.8 fold. Flow cytometry analysis revealed that 3j induced significant accumulation in a dose-dependent manner. After 24h of 3j (10 µM) treatment, the percentage of NCI-H460 cell in S-phase significantly increased (to 93.54 ± 4.4%) compared with control cells (31.67 ± 3.4%). Similarly, the percentage of NCI-H1975 cell in Sphase significantly increased (to 83.99 ± 2.4%) compared with control cells (34.45 ± 3.9%) after treatment with 10µM of 3j. Moreover, increased levels of cyclin A2, CDK2, and decreased levels of cyclin D, cyclin E further confirmed that cell cycle arrest was induced by 3j. Furthermore, molecular docking studies suggested that 3j interacted with Topo I-DNA and DNA-relaxation assay simultaneously confirmed that 3j suppressed the activity of Topo I. Research on the mechanism showed that 3j exhibited anti-tumour activity via activating the DNA damage response pathway and suppressing the repair pathway in NSCLC cells. Conclusion: Novel camptothecin derivative 3j has been demonstrated as a promising antitumor agent and remains to be assessed in further studies.

scholarly journals Imaging flow cytometry as a sensitive tool to detect low-dose-induced DNA damage by analyzing 53BP1 and γH2AX foci in human lymphocytes

2015 ◽  
Vol 87 (12) ◽  
pp. 1070-1078 ◽  
Author(s):  
Matus Durdik ◽  
Pavol Kosik ◽  
Jan Gursky ◽  
Lenka Vokalova ◽  
Eva Markova ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Dna Damage ◽  
Low Dose ◽  
Human Lymphocytes ◽  
Imaging Flow Cytometry ◽  
Γh2ax Foci ◽  
Sensitive Tool

A novel PLK1 inhibitor onvansertib effectively sensitizes MYC-driven medulloblastoma to radiotherapy

2021 ◽  
Author(s):  
Dong Wang ◽  
Bethany Veo ◽  
Angela Pierce ◽  
Susan Fosmire ◽  
Krishna Madhavan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Tumor Growth ◽  
Radiation Treatment ◽  
Tumor Regression ◽  
Tumor Growth Inhibition ◽  
Cell Cycle Distribution ◽  
Cell Renewal ◽  
Group 3

Abstract Background Group 3 medulloblastoma (MB) is often accompanied by MYC amplification. PLK1 is an oncogenic kinase that controls cell cycle and proliferation and has been preclinically validated as a cancer therapeutic target. Onvansertib (PCM-075) is a novel, orally available PLK1 inhibitor, which shows tumor growth inhibition in various types of cancer. We aim to explore the effect of onvansertib on MYC-driven medulloblastoma as a monotherapy or in combination with radiation. Methods Crisper-Cas9 screen was used to discover essential genes for MB tumor growth. Microarray and immunohistochemistry on pediatric patient samples were performed to examine the expression of PLK1. The effect of onvansertib in vitro was measure by cell viability, colony-forming assays, extreme limiting dilution assay and RNA-Seq. ALDH activity, cell-cycle distribution and apoptosis were analyzed by flow cytometry. DNA damage was assessed by immunofluorescence staining. Medulloblastoma xenografts were generated to explore the monotherapy or radio-sensitizing effect. Results PLK1 is overexpressed in Group 3 MB. The IC50 concentrations of onvansertib in Group 3 MB cell lines were in a low nanomolar range. Onvansertib reduced colony formation, cell proliferation, stem cell renewal and induced G2/M arrest in vitro. Moreover, onvansertib in combination with radiation increased DNA damage and apoptosis compare with radiation treatment alone. The combination radiotherapy resulted in marked tumor regression in xenografts. Conclusions These findings demonstrate the efficacy of a novel PLK1 inhibitor onvansertib in vitro and in xenografts of Group 3 MB, which suggests onvansertib is an effective strategy as monotherapy or in combination with radiotherapy in MB.

scholarly journals Binding of a sequence-specific single-stranded DNA-binding factor to the simian virus 40 core origin inverted repeat domain is cell cycle regulated.

1993 ◽  
Vol 13 (1) ◽  
pp. 408-420 ◽  
Author(s):  
E P Carmichael ◽  
J M Roome ◽  
A F Wahl
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Binding ◽  
Dna Synthesis ◽  
Inverted Repeat ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Single Stranded Dna ◽  
Repeat Domain

The inverted repeat domain (IR domain) within the simian virus 40 origin of replication is the site of initial DNA melting prior to the onset of DNA synthesis. The domain had previously been shown to be bound by a cellular factor in response to DNA damage. We demonstrate that two distinct cellular components bind opposite strands of the IR domain. Replication protein A (RPA), previously identified as a single-stranded DNA binding protein required for origin-specific DNA replication in vitro, is shown to have a preference for the pyrimidine-rich strand. A newly described component, IR factor B (IRF-B), specifically recognizes the opposite strand. IRF-B binding activity in nuclear extract varies significantly with cell proliferation and the cell cycle, so that binding of IRF-B to the IR domain is negatively correlated with the onset of DNA synthesis. Loss of IRF-B binding from the nucleus also occurs in response to cellular DNA damage. UV cross-linking indicates that the core binding component of IRF-B is a protein of ca. 34 kDa. We propose that RPA and IRF-B bind opposite strands of the IR domain and together may function in the regulation of origin activation.

scholarly journals Investigating FlowSight® imaging flow cytometry as a platform to assess chemically induced micronuclei using human lymphoblastoid cells in vitro

Mutagenesis ◽  
2018 ◽  
Vol 33 (4) ◽  
pp. 283-289 ◽  
Author(s):  
Jatin R Verma ◽  
Danielle S G Harte ◽  
Ume-Kulsoom Shah ◽  
Huw Summers ◽  
Catherine A Thornton ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Lymphoblastoid Cells ◽  
Imaging Flow Cytometry ◽  
Chemically Induced

scholarly journals In Vitro Regulation of FcRIα Expression on Human Basophils by IgE Antibody

Blood ◽  
1998 ◽  
Vol 91 (5) ◽  
pp. 1633-1643 ◽  
Author(s):  
Donald MacGlashan ◽  
Jane McKenzie-White ◽  
Kristine Chichester ◽  
Bruce S. Bochner ◽  
Frances M. Davis ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Flow Cytometry ◽  
Western Blotting ◽  
Receptor Expression ◽  
In Vivo Studies ◽  
Whole Cell ◽  
Cell Lysates ◽  
Ige Antibody ◽  
Human Basophils

Abstract In vivo studies suggested the possibility of an IgE-dependent regulation of high-affinity (FcRI) IgE receptor expression on basophils. The current studies extend these observations to in vitro cultures of human basophils. Incubation of basophils for 3 to 4 weeks resulted in a slow dissociation of IgE antibody, during which time FcRI expression decreased, as measured by flow cytometry using the anti-FcRIα monoclonal antibody, 22E7, or by measuring FcRIα mass by Western blotting of whole-cell lysates. Culture of basophils with IgE resulted in upregulation of FcRIα expression by both flow cytometry and Western blotting of whole-cell lysates. Upregulation followed a linear time course during 2 weeks of culture. The relative increase in FcRIα density depended on the starting density; with starting densities of FcRIα of 10,000 to 170,000 per basophil, the upregulation varied 20- to 1.1-fold, respectively. Upregulation occurred in high-purity basophils, was not influenced by IgG at concentrations up to 1 mg/mL, and was inhibited by dimeric IgE. Heat-inactivated IgE was less effective and the monoclonal antibody CGP51901 that prevents IgE binding to FcRIα blocked the ability of IgE to induce upregulation. The dose-response curve for IgE-induced upregulation had an effective concentration50 of 230 ng/mL. Although the receptor through which IgE induces this upregulation is not yet known, several characteristics suggest that the upregulation is mediated by IgE interacting through FcRIα itself.

Growth Inhibition of Nasopharyngeal Carcinoma Cells Mediated by p53 Gene-Containing Nanolipid Composites

2020 ◽  
Vol 20 (10) ◽  
pp. 6026-6032
Author(s):  
Yongshan Cheng ◽  
Shanying Wu ◽  
Xinting Tie ◽  
Xiaodong Huang ◽  
Lihua Cui
Keyword(s):  
Cell Cycle ◽  
Flow Cytometry ◽  
Nasopharyngeal Carcinoma ◽  
Growth Inhibition ◽  
Transfection Efficiency ◽  
P53 Gene ◽  
Theoretical Support ◽  
Novel Drugs ◽  
Cellular Apoptosis

To study the growth inhibition and cell cycle changes in nasopharyngeal carcinoma (CNE1) cells after transfection with p53 gene. A mixture of nano-liposomes and plasmid containing p53 was used for transfecting CNE1 cells. Cellular apoptosis was examined after transfection using the CCK-8 reagent method with flow cytometry. The results showed that a ratio of nanoliposome/p-ORF-GFP of 3.5:1 showed the highest transfection efficiency in CNE1 cells. The cells transfected with a mixture of composites in this proportion showed significant apoptosis of up to 50–70%. In addition, we observed that cell cycle changes-measured using flow cytometry-as well as cellular apoptosis were accelerated after administration of composites. The CCK-8 kit was used to determine the viability of nano-liposome-encapsulated p53 transfected cells. In vitro experiments showed that the combination significantly inhibited the growth of CNE1 cells with an inhibition rate of approximately 63.8%. Therefore, the nanocomposites have a significant effect on inhibiting the growth of CNE1 cells. Through the investigation of apoptosis and cell cycle changes in CNE1 cells we found that the nanoliposome-encapsulated p53 gene can inhibit growth in these cells, and might therefore serve as a novel treatment strategy for adjuvant treatment of nasopharyngeal carcinoma and ca also reduce incompatibility issues with radiotherapy and chemotherapy. This method can also provide technical and theoretical support for the development of novel drugs.

scholarly journals PHF2 histone demethylase prevents DNA damage and genome instability by controlling cell cycle progression of neural progenitors

2019 ◽  
Vol 116 (39) ◽  
pp. 19464-19473 ◽  
Author(s):  
Stella Pappa ◽  
Natalia Padilla ◽  
Simona Iacobucci ◽  
Marta Vicioso ◽  
Elena Álvarez de la Campa ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Genome Stability ◽  
Cell Cycle Progression ◽  
Genome Instability ◽  
Neural Progenitors ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Biochemical Assays

Histone H3 lysine 9 methylation (H3K9me) is essential for cellular homeostasis; however, its contribution to development is not well established. Here, we demonstrate that the H3K9me2 demethylase PHF2 is essential for neural progenitor proliferation in vitro and for early neurogenesis in the chicken spinal cord. Using genome-wide analyses and biochemical assays we show that PHF2 controls the expression of critical cell cycle progression genes, particularly those related to DNA replication, by keeping low levels of H3K9me3 at promoters. Accordingly, PHF2 depletion induces R-loop accumulation that leads to extensive DNA damage and cell cycle arrest. These data reveal a role of PHF2 as a guarantor of genome stability that allows proper expansion of neural progenitors during development.

scholarly journals The Rational Design and Biological Mechanisms of Nanoradiosensitizers

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 504 ◽  
Author(s):  
Hainan Sun ◽  
Xiaoling Wang ◽  
Shumei Zhai
Keyword(s):  
Oxidative Stress ◽  
Cell Cycle ◽  
Dna Damage ◽  
Rational Design ◽  
Design Strategies ◽  
Biological Mechanisms ◽  
Normal Tissues ◽  
Current State

Radiotherapy (RT) has been widely used for cancer treatment. However, the intrinsic drawbacks of RT, such as radiotoxicity in normal tissues and tumor radioresistance, promoted the development of radiosensitizers. To date, various kinds of nanoparticles have been found to act as radiosensitizers in cancer radiotherapy. This review focuses on the current state of nanoradiosensitizers, especially the related biological mechanisms, and the key design strategies for generating nanoradiosensitizers. The regulation of oxidative stress, DNA damage, the cell cycle, autophagy and apoptosis by nanoradiosensitizers in vitro and in vivo is highlighted, which may guide the rational design of therapeutics for tumor radiosensitization.

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