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Nanosecond Electric Pulses Induce Early and Late Phases of DNA Damage and Cell Death in Cisplatin-Resistant Human Ovarian Cancer Cells. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4504895. [PMID: 30186858 PMCID: PMC6112222 DOI: 10.1155/2018/4504895] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/26/2018] [Accepted: 07/11/2018] [Indexed: 12/20/2022]
Abstract
Chemoresistance is a challenge for management of ovarian cancer, and therefore the response of resistant cells to nanosecond electric pulses (nsEP) was explored. Human ovarian cancer cell line COC1 and the cisplatin-resistant subline COC1/DDP were subjected to nsEP (32 ns, 10 kV/cm, 10 Hz pulse repletion frequency, and 10 min exposure duration), and then the cellular responses were followed. The percentages of dead cells and of comet-formed cells in the alkaline assay displayed two peak levels (i.e., 2 and 8 h after nsEP exposure), with the highest value noted at 8 h; the percentage of comet-formed cells in the neutral assay was increased at 8 h; the apoptotic percentage was increased at 8 h, with collapse of the mitochondrial membrane potential and the activation of caspase-3 and caspase-9. The comet assay demonstrated DNA single-strand break at 2 h and double-strand break at 8 h. nsEP resulted in lower cytotoxicity in COC1/DDP cells compared with COC1 cells. These findings indicated that nsEP induced early and late phases of DNA damage and cell death, and these two types of cell death may have distinct applications to treatments of chemoresistant ovarian cancers.
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Blanchard LS, Monin A, Ouertani H, Touaibia L, Michel E, Buret F, Simonet P, Morris CE, Demanèche S. Survival and electrotransformation of Pseudomonas syringae strains under simulated cloud-like conditions. FEMS Microbiol Ecol 2017; 93:3778241. [PMID: 28459967 DOI: 10.1093/femsec/fix057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/27/2017] [Indexed: 11/13/2022] Open
Abstract
To diversify their genetic material, and thereby allow adaptation to environmental disturbances and colonization of new ecological niches, bacteria use various evolutionary processes, including the acquisition of new genetic material by horizontal transfer mechanisms such as conjugation, transduction and transformation. Electrotransformation mediated by lightning-related electrical phenomena may constitute an additional gene-transfer mechanism occurring in nature. The presence in clouds of bacteria such as Pseudomonas syringae capable of forming ice nuclei that lead to precipitation, and that are likely to be involved in triggering lightning, led us to postulate that natural electrotransformation in clouds may contribute to the adaptive potential of these bacteria. Here, we quantify the survival rate of 10 P. syringae strains in liquid and icy media under such electrical pulses and their capacity to acquire exogenous DNA. In comparison to two other bacteria (Pseudomonas sp. N3 and Escherichia coli TOP10), P. syringae CC0094 appears to be best adapted for survival and for genetic electrotransformation under these conditions, which suggests that this bacterium would be able to survive and to get a boost in its adaptive potential while being transported in clouds and falling back to Earth with precipitation from storms.
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Affiliation(s)
- Laurine S Blanchard
- Université de Lyon, École Centrale de Lyon, Laboratoire Ampére (CNRS UMR5005), Environmental Microbial Genomics, 69134 Ecully Cedex, France
| | - Anaïs Monin
- Université de Lyon, École Centrale de Lyon, Laboratoire Ampére (CNRS UMR5005), Environmental Microbial Genomics, 69134 Ecully Cedex, France
| | - Hounaïda Ouertani
- Université de Lyon, École Centrale de Lyon, Laboratoire Ampére (CNRS UMR5005), Environmental Microbial Genomics, 69134 Ecully Cedex, France
| | - Lamia Touaibia
- Université de Lyon, École Centrale de Lyon, Laboratoire Ampére (CNRS UMR5005), Environmental Microbial Genomics, 69134 Ecully Cedex, France
| | - Elisa Michel
- Université de Lyon, École Centrale de Lyon, Laboratoire Ampére (CNRS UMR5005), Environmental Microbial Genomics, 69134 Ecully Cedex, France
| | - François Buret
- Université de Lyon, École Centrale de Lyon, Laboratoire Ampére (CNRS UMR5005), Environmental Microbial Genomics, 69134 Ecully Cedex, France
| | - Pascal Simonet
- Université de Lyon, École Centrale de Lyon, Laboratoire Ampére (CNRS UMR5005), Environmental Microbial Genomics, 69134 Ecully Cedex, France
| | - Cindy E Morris
- INRA, UR0407 Pathologie Végétale, 84143 Montfavet Cedex, France
| | - Sandrine Demanèche
- Université de Lyon, École Centrale de Lyon, Laboratoire Ampére (CNRS UMR5005), Environmental Microbial Genomics, 69134 Ecully Cedex, France
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Lu W, Wu K, Hu X, Xie X, Ning J, Wang C, Zhou H, Yang G. Theoretical analysis of transmembrane potential of cells exposed to nanosecond pulsed electric field. Int J Radiat Biol 2016; 93:231-239. [PMID: 27586355 DOI: 10.1080/09553002.2017.1230244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
PURPOSE Intracellular electroporation occurs when the cells are exposed to nanosecond pulsed electric field (nsPEF). It is believed the electroporation (formation and extension of pores on the membrane induced by external electric field) is affected significantly by the transmembrane potential. This paper analyzed transmembrane potential induced by nsPEF in the term of pulse frequency spectrum, aiming to provide a theoretical explanation to intracellular bio-effects. METHODS Based on the double-shelled spherical cell model, the frequency dependence of transmembrane potential was obtained by solving Laplace's equation, while the time course of transmembrane potential was obtained by a method combined with discrete Fourier transform and Laplace transform. First-order Debye equation was used to describe the dielectric relaxation of the cell medium. RESULTS Frequency-domain analysis showed that when the electric field frequency was higher than 105 Hz, the transmembrane potential on the organelle membrane (ΔΦo) was increasing to exceed the transmembrane potential on the cellular membrane (ΔΦc). In the time-domain analysis, transmembrane potentials induced by four nsPEF (short trapezoid, long trapezoid, bipolar and sine shapes) with the same field strength were compared with each other. It showed that ΔΦo is obviously larger than ΔΦc if the curve of the normalized frequency spectrum of the pulse is more similar with the curve of normalized ΔΦo in frequency domain. Pulses with major frequency components higher than 108 Hz lead to both small ΔΦo and ΔΦc. This may explain why high power pulsed microwave lead to unobvious bio-effects of cells than nsPEF with trapezoid form. CONCLUSION Through the pulse frequency spectrum it is clearer to understand the relationship between nsPEF and the transmembrane potential.
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Affiliation(s)
- Wei Lu
- a Laboratory of Health Physics , Beijing Institute of Radiation Medicine , Beijing , China
| | - Ke Wu
- a Laboratory of Health Physics , Beijing Institute of Radiation Medicine , Beijing , China
| | - Xiangjun Hu
- b Laboratory of Experimental Pathology , Beijing Institute of Radiation Medicine , Beijing , China
| | - Xiangdong Xie
- a Laboratory of Health Physics , Beijing Institute of Radiation Medicine , Beijing , China
| | - Jing Ning
- a Laboratory of Health Physics , Beijing Institute of Radiation Medicine , Beijing , China
| | - Changzhen Wang
- b Laboratory of Experimental Pathology , Beijing Institute of Radiation Medicine , Beijing , China
| | - Hongmei Zhou
- a Laboratory of Health Physics , Beijing Institute of Radiation Medicine , Beijing , China
| | - Guoshan Yang
- a Laboratory of Health Physics , Beijing Institute of Radiation Medicine , Beijing , China
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Chopinet L, Rols MP. Nanosecond electric pulses: A mini-review of the present state of the art. Bioelectrochemistry 2015; 103:2-6. [DOI: 10.1016/j.bioelechem.2014.07.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 07/20/2014] [Accepted: 07/24/2014] [Indexed: 01/08/2023]
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Wu S, Guo J, Wei W, Zhang J, Fang J, Beebe SJ. Enhanced breast cancer therapy with nsPEFs and low concentrations of gemcitabine. Cancer Cell Int 2014; 14:98. [PMID: 25379013 PMCID: PMC4209047 DOI: 10.1186/s12935-014-0098-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 09/17/2014] [Indexed: 12/27/2022] Open
Abstract
Background Chemotherapy either before or after surgery is a common breast cancer treatment. Long-term, high dose treatments with chemotherapeutic drugs often result in undesirable side effects, frequent recurrences and resistances to therapy. Methods The anti-cancer drug, gemcitabine (GEM) was used in combination with pulse power technology with nanosecond pulsed electric fields (nsPEFs) for treatment of human breast cancer cells in vitro. Two strategies include sensitizing mammary tumor cells with GEM before nsPEF treatment or sensitizing cells with nsPEFs before GEM treatment. Breast cancer cell lines MCF-7 and MDA-MB-231 were treated with 250 65 ns-duration pulses and electric fields of 15, 20 or 25 kV/cm before or after treatment with 0.38 μM GEM. Results Both cell lines exhibited robust synergism for loss of cell viability 24 h and 48 h after treatment; treatment with GEM before nsPEFs was the preferred order. In clonogenic assays, only MDA-MB-231 cells showed synergism; again GEM before nsPEFs was the preferred order. In apoptosis/necrosis assays with Annexin-V-FITC/propidium iodide 2 h after treatment, both cell lines exhibited apoptosis as a major cell death mechanism, but only MDA-MB-231 cells exhibited modest synergism. However, unlike viability assays, nsPEF treatment before GEM was preferred. MDA-MB-231 cells exhibited much greater levels of necrosis then in MCF-7 cells, which were very low. Synergy was robust and greater when nsPEF treatment was before GEM. Conclusions Combination treatments with low GEM concentrations and modest nsPEFs provide enhanced cytotoxicity in two breast cancer cell lines. The treatment order is flexible, although long-term survival and short-term cell death analyses indicated different treatment order preferences. Based on synergism, apoptosis mechanisms for both agents were more similar in MCF-7 than in MDA-MB-231 cells. In contrast, necrosis mechanisms for the two agents were distinctly different in MDA-MB-231, but too low to reliably evaluate in MCF-7 cells. While disease mechanisms in the two cell lines are different based on the differential synergistic response to treatments, combination treatment with GEM and nsPEFs should provide an advantageous therapy for breast cancer ablation in vivo.
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Affiliation(s)
- Shan Wu
- College of Engineering, Peking University, Beijing, 100871 China
| | - Jinsong Guo
- College of Engineering, Peking University, Beijing, 100871 China
| | - Wendong Wei
- College of Engineering, Peking University, Beijing, 100871 China
| | - Jue Zhang
- College of Engineering, Peking University, Beijing, 100871 China ; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871 China
| | - Jing Fang
- College of Engineering, Peking University, Beijing, 100871 China
| | - Stephen J Beebe
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA 23508 USA
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In vivo effects of focused shock waves on tumor tissue visualized by fluorescence staining techniques. Bioelectrochemistry 2014; 103:103-10. [PMID: 25200989 DOI: 10.1016/j.bioelechem.2014.08.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 08/13/2014] [Accepted: 08/18/2014] [Indexed: 11/23/2022]
Abstract
Shock waves can cause significant cytotoxic effects in tumor cells and tissues both in vitro and in vivo. However, understanding the mechanisms of shock wave interaction with tissues is limited. We have studied in vivo effects of focused shock waves induced in the syngeneic sarcoma tumor model using the TUNEL assay, immunohistochemical detection of caspase-3 and hematoxylin-eosin staining. Shock waves were produced by a multichannel pulsed-electrohydraulic discharge generator with a cylindrical ceramic-coated electrode. In tumors treated with shock waves, a large area of damaged tissue was detected which was clearly differentiated from intact tissue. Localization and a cone-shaped region of tissue damage visualized by TUNEL reaction apparently correlated with the conical shape and direction of shock wave propagation determined by high-speed shadowgraphy. A strong TUNEL reaction of nuclei and nucleus fragments in tissue exposed to shock waves suggested apoptosis in this destroyed tumor area. However, specificity of the TUNEL technique to apoptotic cells is ambiguous and other apoptotic markers (caspase-3) that we used in our study did not confirmed this observation. Thus, the generated fragments of nuclei gave rise to a false TUNEL reaction not associated with apoptosis. Mechanical stress from high overpressure shock wave was likely the dominant pathway of tumor damage.
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Tolstykh GP, Beier HT, Roth CC, Thompson GL, Payne JA, Kuipers MA, Ibey BL. Activation of intracellular phosphoinositide signaling after a single 600 nanosecond electric pulse. Bioelectrochemistry 2013; 94:23-9. [DOI: 10.1016/j.bioelechem.2013.05.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 03/10/2013] [Accepted: 05/13/2013] [Indexed: 02/03/2023]
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Beebe SJ, Schoenbach KH, Heller R. Bioelectric applications for treatment of melanoma. Cancers (Basel) 2010; 2:1731-70. [PMID: 24281185 PMCID: PMC3837335 DOI: 10.3390/cancers2031731] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 09/14/2010] [Accepted: 09/15/2010] [Indexed: 01/04/2023] Open
Abstract
Two new cancer therapies apply bioelectric principles. These methods target tumor structures locally and function by applying millisecond electric fields to deliver plasmid DNA encoding cytokines using electrogene transfer (EGT) or by applying rapid rise-time nanosecond pulsed electric fields (nsPEFs). EGT has been used to locally deliver cytokines such as IL-12 to activate an immune response, resulting in bystander effects. NsPEFs locally induce apoptosis-like effects and affect vascular networks, both promoting tumor demise and restoration of normal vascular homeostasis. EGT with IL-12 is in melanoma clinical trials and nsPEFs are used in models with B16F10 melanoma in vitro and in mice. Applications of bioelectrics, using conventional electroporation and extensions of it, provide effective alternative therapies for melanoma.
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Affiliation(s)
- Stephen J Beebe
- Frank Reidy Research Center for Bioelectrics/Old Dominion University 4211 Monarch Way, Suite 300, Norfolk, Virginia 23508, USA.
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