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12. Assessment of the tumourigenic and metastatic properties of SK-MEL28 melanoma cells surviving electrochemotherapy with bleomycinVesna Todorović, Gregor Serša, Vid Mlakar, Damjan Glavač, Maja Čemažar, 2012, izvirni znanstveni članek Povzetek: Background. Electrochemotherapy is a local treatment combining chemotherapy and electroporation and is highly effective treatment approach for subcutaneous tumours of various histologies. Contrary to surgery and radiation, the effect of electrochemotherapy on metastatic potential of tumour cells has not been extensively studied. The aim of the study was to evaluate the effect of electrochemotherapy with bleomycin on the metastatic potential of human melanoma cells in vitro. Materials and methods. Viable cells 48 hours after electrochemotherapy were tested for their ability to migrate and invade through Matrigel coated porous membrane. In addition, microarray analysis and quantitative Real-Time PCR were used to detect changes in gene expression after electrochemotherapy. Results. Cell migration and invasion were not changed in melanoma cells surviving electrochemotherapy.Interestingly, only a low number of tumourigenesis related genes was differentially expressed after electrochemotherapy. Conclusions. Our data suggest that metastatic potential of human melanoma cells is not affected by electrochemotherapy with bleomycin, confirming safe role of electrochemotherapy in the clinics.
Objavljeno v DiRROS: 21.03.2024; Ogledov: 306; Prenosov: 51
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14. Cathepsin H indirectly regulates morphogenetic protein-4 (BMP-4) in various human cell linesMatija Rojnik, Zala Jevnikar, Bojana Mirković, Damjan Janeš, Nace Zidar, Danijel Kikelj, Janko Kos, 2011, izvirni znanstveni članek Povzetek: Background. Cathepsin H is a cysteine protease considered to play a major role in tumor progression, however, its precise function in tumorigenesis is unclear. Cathepsin H was recently proposed to be involved in processing of bone morphogenetic protein 4 (BMP-4) in mice. In order to clarify whether cathepsin H also regulates BMP-4 in humans, its impact on BMP-4 expression, processing and degradation was investigated in prostate cancer (PC-3), osteosarcoma (HOS) and pro-monocytic (U937) human cell lines. Materials and methods. BMP-4 expression was founded to be regulated by cathepsin H using PCR array technology and confirmed by real time PCR. Immunoassays including Western blot and confocal microscopy were used to evaluate the influence of cathepsin H on BMP-4 processing. Results. In contrast to HOS, the expression of BMP-4 mRNA in U937 and PC3 cells was significantly decreased by cathepsin H. The different regulation of BMP-4 synthesis could be associated with the absence of the mature 28 kDa cathepsin H form in HOS cells, where only the intermediate 30 kDa form was observed. No co-localization of BMP-4 and cathepsin H was observed in human cell lines and the multistep processing of BMP-4 was not altered in the presence of specific cathepsin H inhibitor. Isolated cathepsin H does not cleave mature recombinant BMP-4, neither with its amino- nor its endopeptidase activity. Conclusions. Our results exclude direct proteolytic processing of BMP-4 by cathepsin H, however, they provide support for its involvement in the regulation of BMP-4 expression.
Objavljeno v DiRROS: 18.03.2024; Ogledov: 245; Prenosov: 275
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15. Cathepsin H indirectly regulates morphogenetic protein-4 (BMP-4) in various human cell linesMatija Rojnik, Zala Jevnikar, Bojana Mirković, Damjan Janeš, Nace Zidar, Danijel Kikelj, Janko Kos, 2011, izvirni znanstveni članek Povzetek: Background. Cathepsin H is a cysteine protease considered to play a major role in tumor progression, however, its precise function in tumorigenesis is unclear. Cathepsin H was recently proposed to be involved in processing of bone morphogenetic protein 4 (BMP-4) in mice. In order to clarify whether cathepsin H also regulates BMP-4 in humans, its impact on BMP-4 expression, processing and degradation was investigated in prostate cancer (PC-3), osteosarcoma (HOS) and pro-monocytic (U937) human cell lines. Materials and methods. BMP-4 expression was founded to be regulated by cathepsin H using PCR array technology and confirmed by real time PCR. Immunoassays including Western blot and confocal microscopy were used to evaluate the influence of cathepsin H on BMP-4 processing. Results. In contrast to HOS, the expression of BMP-4 mRNA in U937 and PC3 cells was significantly decreased by cathepsin H. The different regulation of BMP-4 synthesis could be associated with the absence of the mature 28 kDa cathepsin H form in HOS cells, where only the intermediate 30 kDa form was observed. No co-localization of BMP-4 and cathepsin H was observed in human cell lines and the multistep processing of BMP-4 was not altered in the presence of specific cathepsin H inhibitor. Isolated cathepsin H does not cleave mature recombinant BMP-4, neither with its amino- nor its endopeptidase activity. Conclusions. Our results exclude direct proteolytic processing of BMP-4 by cathepsin H, however, they provide support for its involvement in the regulation of BMP-4 expression.
Objavljeno v DiRROS: 18.03.2024; Ogledov: 101; Prenosov: 21
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17. Cell size dynamics and viability of cells exposed to hypotonic treatment and electroporation for electrofusion optimizationMarko Ušaj, Katja Trontelj, Rosana Hudej, Maša Kandušer, Damijan Miklavčič, 2009, izvirni znanstveni članek Povzetek: Background. Various electrofusion parameters have to be adjusted to obtain theoptimal electrofusion efficiency. Based on published data, good electrofusion conditions can be achieved with the hypotonic treatment. However, the duration of the hypotonic treatment before electroporation and buffer hypoosmolarity have to be adjusted in order to cause cell swelling, to avoid regulatory volume decrease and to preserve cell viability. The aims of our study were to determine cell size dynamics and viability of four different cell lines in hypotonic buffer and to study the influence of the electroporation on the selected cell line in hypotonic buffer. Materials and methods. Cell size dynamics of different cell lines exposed to hypotonic buffer and electroporation were analyzed by time-resolvedcell size measurements. The viability of hypotonically treated oržand electroporated cells was determined 24 h after the experiment by a modified crystal violet (CV) viability assay. Results. In our experimental conditions the hypotonic treatment at 100 mOsm was efficient for CHO, V79 and B16-F1 cell lines. The optimal duration of the treatment was between two and five minutes. On the other hand the same hypotonic treatment did not cause cell swelling of NS1 cells. Cell swelling was also observed after electroporation of B16-F1 in isotonic buffer and it was amplified when hypotonic buffer was used. In addition, the regulatory volume decrease was successfully inhibited with electroporation. Conclusions. Cell size dynamicsin hypotonic conditions should be studied for each cell line since they differ in their sensitivity to the hypotonic treatment. The inhibition of cell regulatory volume decrease by electroporation may be beneficial in achieving higher electrofusion efficiency. (Abstract truncated at 2000 characters)
Ključne besede: hypotonic treatment, cell swelling, regulatory volume decrease, cell size measurements, viability, electrofusion, electroporation
Objavljeno v DiRROS: 08.03.2024; Ogledov: 120; Prenosov: 36
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18. Optimization of electrode position and electric pulse amplitude in electrochemotherapyAnže Županič, Selma Čorović, Damijan Miklavčič, 2008, izvirni znanstveni članek Povzetek: Background. In addition to the chemotherapeutic drug being present within the tumor during electric pulse delivery, successful electrochemotherapy requires the entire tumor volume to be subjected to a sufficiently high electric field,while the electric field in the surrounding healthy tissue is as low as possible to prevent damage. Both can be achieved with appropriate positioning of the electrodes and appropriate amplitude of electric pulses. Methods. We used 3D finite element numerical models and a genetic optimization algorithm to determine the optimum electrode configuration and optimum amplitude of electric pulses for treatment of three subcutaneous tumor models of different shapes and sizes and a realistic brain tumor model acquired from medical images. Results. In all four tumor cases, parallel needle electrode arrays were a better choice than hexagonal needle electrode arrays, since their utilization required less electric current and caused less healthy tissue damage. In addition, regardless of tumor geometry or needle electrode configuration, the optimum depth of electrode insertion was in all cases deeper than the deepest part of the tumor. Conclusions. Our optimization algorithm was able to determine the best electrode configuration in all four presented models and with further improvement it could be a useful tool in clinical electrochemotherapy treatment planning.
Objavljeno v DiRROS: 08.03.2024; Ogledov: 92; Prenosov: 28
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19. Numerical modeling in electroporation-based biomedical applicationsNataša Pavšelj, Damijan Miklavčič, 2008, izvirni znanstveni članek Povzetek: Background. Numerous experiments have to be performed before a biomedical application is put to practical use in clinical environment. As a complementary work to in vitro, in vivo and medical experiments, we can use analytical and numerical models to represent, as realistically as possible, real biological phenomena of, in our case, electroporation. In this way we canevaluate different electrical parameters in advance, such as pulse amplitude, duration, number of pulses, or different electrode geometries. Suchnumerical models can contribute significantly to the understanding of an experiment and treatment planning as well as to the design of new electroporation devices and electrodes. Methods. We used commercially available modeling software, based on finite element method. We constructed a model of a subcutaneous tumor during electrochemotherapy (EMAS) and a model ofskin during gene electrotransfer (COMSOL Multiphysics). Tissue-electrode geometries, pulse parameters and currentvoltage measurements from in vivo experiments were used to develop and validate the models. Results. To describeadequately our in vivo observations, a tissue conductivity increase during electroporation was included in our numerical models. The output currents of the models were compared to the currents and the voltages measuredduring in vivo experiments and a good agreement was obtained. Also, when comparing the voltages needed for a successful electropermeabilization assuggested by the models, to voltages applied in experiments and achieving a successful electrochemotherapy or in vivo gene electrotransfer, good agreementcan be observed. Conclusions. Modeling of electric current and electric field distribution during cell and tissue electroporation proves to be helpful in describing different aspects of the process and allowing us to design electrodes and electroporation protocols as a part of treatment planning.
Ključne besede: electroporation, gene electrotransfer, electrochemotherapy, subcutaneous tumor, finite-element method
Objavljeno v DiRROS: 07.03.2024; Ogledov: 130; Prenosov: 36
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20. Electrochemotherapy of tumoursGregor Serša, Maja Čemažar, Damijan Miklavčič, Zvonimir Rudolf, 2006, pregledni znanstveni članek Povzetek: Electroehemotherapy consists of chemotherapy followed by local application of electrie pulses to the tumour to increase drug delivery into cells. Drug uptake can be inereased by electroporation for only those drugs whose transport through the plasma membrane is impeded. Among many drugs that have been tested so far, only bleomycin and cisplatin found their way from preclinical testing to clinical trials. In vitro studies demonstrated several fold inerease of their cytotoxicity after electroporation of cells. In vivo, electroporation of tumours after local or systemic administration of either ofthe drugs, i.e. electrochemotherapy, proved to be an effective antitumour treatment. In preclinical studies on several tumour models, electrochemotherapy either with bleomycin or cisplatin was elaborated and parameters for effective local tumour control were determined. In veterinary medicine, electrochemotherapy also proved to be effective in the treatment of primary tumours in cats, dogs and horses. In human clinical studies, electrochemotherapy was performed on the patients with progressive disease andaccessible tumour nodules of different malignancies. All clinical studies demonstrated that electrochemotherapy is an effective treatment for local tumour control in cancer patients.
Objavljeno v DiRROS: 15.02.2024; Ogledov: 143; Prenosov: 42
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