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Liang H, Zhang Y, Chen D, Tan H, Zheng Y, Wang J, Chen J. Characterization of Single-Nucleus Electrical Properties by Microfluidic Constriction Channel. MICROMACHINES 2019; 10:mi10110740. [PMID: 31683555 PMCID: PMC6915630 DOI: 10.3390/mi10110740] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 10/26/2019] [Accepted: 10/29/2019] [Indexed: 02/07/2023]
Abstract
As key bioelectrical markers, equivalent capacitance (Cne, i.e., capacitance per unit area) and resistance (Rne, i.e., resistivity multiply thickness) of nuclear envelopes have emerged as promising electrical indicators, which cannot be effectively measured by conventional approaches. In this study, single nuclei were isolated from whole cells and trapped at the entrances of microfluidic constriction channels, and then corresponding impedance profiles were sampled and translated into single-nucleus Cne and Rne based on a home-developed equivalent electrical model. Cne and Rne of A549 nuclei were first quantified as 3.43 ± 1.81 μF/cm2 and 2.03 ± 1.40 Ω·cm2 (Nn = 35), which were shown not to be affected by variations of key parameters in nuclear isolation and measurement. The developed approach in this study was also used to measure a second type of nuclei, producing Cne and Rne of 3.75 ± 3.17 μF/cm2 and 1.01 ± 0.70 Ω·cm2 for SW620 (Nn = 17). This study may provide a new perspective in single-cell electrical characterization, enabling cell type classification and cell status evaluation based on bioelectrical markers of nuclei.
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Affiliation(s)
- Hongyan Liang
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China.
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 101408, China.
| | - Yi Zhang
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China.
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 101408, China.
| | - Deyong Chen
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China.
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 101408, China.
| | - Huiwen Tan
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China.
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 101408, China.
| | - Yu Zheng
- Shandong University, Jinan 250100, China.
| | - Junbo Wang
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China.
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 101408, China.
| | - Jian Chen
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China.
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 101408, China.
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Mobilization of Copper ions by Flavonoids in Human Peripheral Lymphocytes Leads to Oxidative DNA Breakage: A Structure Activity Study. Int J Mol Sci 2015; 16:26754-69. [PMID: 26569217 PMCID: PMC4661851 DOI: 10.3390/ijms161125992] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/29/2015] [Accepted: 10/30/2015] [Indexed: 11/16/2022] Open
Abstract
Epidemiological studies have linked dietary consumption of plant polyphenols with lower incidence of various cancers. In particular, flavonoids (present in onion, tomato and other plant sources) induce apoptosis and cytotoxicity in cancer cells. These can therefore be used as lead compounds for the synthesis of novel anticancer drugs with greater bioavailability. In the present study, we examined the chemical basis of cytotoxicity of flavonoids by studying the structure–activity relationship of myricetin (MN), fisetin (FN), quercetin (QN), kaempferol (KL) and galangin (GN). Using single cell alkaline gel electrophoresis (comet assay), we established the relative efficiency of cellular DNA breakage as MN > FN > QN > KL > GN. Also, we determined that the cellular DNA breakage was the result of mobilization of chromatin-bound copper ions and the generation of reactive oxygen species. The relative DNA binding affinity order was further confirmed using molecular docking and thermodynamic studies through the interaction of flavonoids with calf thymus DNA. Our results suggest that novel anti-cancer molecules should have ortho-dihydroxy groups in B-ring and hydroxyl groups at positions 3 and 5 in the A-ring system. Additional hydroxyl groups at other positions further enhance the cellular cytotoxicity of the flavonoids.
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Chibber S, Hassan I, Farhan M, Naseem I. In vitro pro-oxidant action of Methotrexate in presence of white light. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2011; 104:387-93. [PMID: 21570314 DOI: 10.1016/j.jphotobiol.2011.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 04/06/2011] [Accepted: 04/11/2011] [Indexed: 10/18/2022]
Abstract
Methotrexate (MTX) an anti-cancer drug as well as a photosensitizer is able to generate reactive oxygen species (ROS). Cu (II) is present associated with chromatin in cancer cells and has been shown to be capable of mediating the action of several anti-cancer drugs through production of ROS. The objective of the present study is to determine Cu (II) mediated anti-cancer mechanism of MTX under photoilluminated condition as well as alone, using alkaline single cell gel electrophoresis (comet assay). We have shown that cellular DNA breakage was enhanced when Cu (II) is used with MTX as compared to MTX alone. It is also shown that MTX alone as well as in combination with Cu (II) is able to generate oxidative stress in lymphocyte which is inhibited by scavengers of ROS but the pattern of inhibition was differential as was also demonstrated by plasmid nicking assay. Thus, we can say that MTX exhibit pro-oxidant action in presence of white light which gets elevated in presence of Cu (II). Hence, we propose that the mobilization of endogenous copper is possibly involved in killing of cancer cells by MTX during chemo-radio therapy besides acting as antifolate.
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Affiliation(s)
- Sandesh Chibber
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslin University, Aligarh, UP 202 002, India
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An endogenous calcium-dependent, caspase-independent intranuclear degradation pathway in thymocyte nuclei: antagonism by physiological concentrations of K(+) ions. Exp Cell Res 2008; 314:1237-49. [PMID: 18294629 DOI: 10.1016/j.yexcr.2007.12.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 12/10/2007] [Accepted: 12/27/2007] [Indexed: 12/20/2022]
Abstract
Calcium ions have been implicated in apoptosis for many years, however the precise role of this ion in the cell death process remains incomplete. We have extensively examined the role of Ca(2+) on nuclear degradation in vitro using highly purified nuclei isolated from non-apoptotic rat thymocytes. We show that these nuclei are devoid of CAD (caspase-activated DNase), and DNA degradation occurs independent of caspase activity. Serine proteases rather than caspase-3 appear necessary for this Ca(2+) -dependent DNA degradation in nuclei. We analyzed nuclei treated with various concentrations of Ca(2+) in the presence of both a physiological (140 mM) and apoptotic (40 mM) concentration of KCl. Our results show that a 5-fold increase in Ca(2+) is required to induce DNA degradation at the physiological KCl concentration compared to the lower, apoptotic concentration of the cation. Ca(2+) -induced internucleosomal DNA degradation was also accompanied by the release of histones, however the apoptotic-specific phosphorylation of histone H2B does not occur in these isolated nuclei. Interestingly, physiological concentrations of K(+) inhibit both Ca(2+) -dependent DNA degradation and histone release suggesting that a reduction of intracellular K(+) is necessary for this apoptosis-associated nuclear degradation in cells. Together, these data define an inherent caspase-independent catabolic pathway in thymocyte nuclei that is sensitive to physiological concentrations of intracellular cations.
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Franco-Obregón A, Wang HW, Clapham DE. Distinct ion channel classes are expressed on the outer nuclear envelope of T- and B-lymphocyte cell lines. Biophys J 2000; 79:202-14. [PMID: 10866948 PMCID: PMC1300926 DOI: 10.1016/s0006-3495(00)76284-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The outer nuclear membrane, endoplasmic reticulum, and mitochondrial membrane ion channels are poorly understood, although they are important in the control of compartmental calcium levels, cell division, and apoptosis. Few direct recordings of these ion channels have been made because of the difficulty of accessing these intracellular membranes. Using patch-clamp techniques on isolated nuclei, we measured distinct ion channel classes on the outer nuclear envelope of T-cell (human Jurkat) and BFL5 cell (murine promyelocyte) lines. We first imaged the nuclear envelopes of both Jurkat and FL5 cells with atomic force microscopy to determine the density of pore proteins. The nuclear pore complex was intact at roughly similar densities in both cell types. In patch-clamp recordings of Jurkat nuclear membranes, Cl channels (105 +/- 5 pS) predominated and inactivated with negative pipette potentials. Nucleotides transiently inhibited the anion channel. In contrast, FL5 nuclear channels were cation selective (52 +/- 2 pS), were inactivated with positive membrane potentials, and were insensitive to GTPgammaS applied to the bath. We hypothesize that T- and B-cell nuclear membrane channels are distinct, and that this is perhaps related to their unique roles in the immune system.
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Affiliation(s)
- A Franco-Obregón
- Solid State Physics Laboratory, ETH Zurich, CH 8093 Zurich, Switzerland
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