1. Vzpostavitev elektroprenosa sistema transpomnožujočih mRNA na modelu mišjega melanoma B16-F10 in vitro in in vivoJaka Vrevc Žlajpah, Urška Kamenšek, Urša Lampreht Tratar, Maja Čemažar, Gregor Serša, Katja Uršič Valentinuzzi, 2025, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: elektrokemoterapija, eksperimentalna onkologija, melanom
Objavljeno v DiRROS: 18.03.2026; Ogledov: 241; Prenosov: 81
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2. Elektrokemoterapija z bleomicinom, cisplatinom ali oksaliplatinom na mišjih tumorskih modelih : od ablacije do vakcinacije in situKatja Uršič Valentinuzzi, Urška Kamenšek, Simona Kranjc Brezar, Chloe Heranney, Tilen Komel, Simon Buček, Maja Čemažar, Gregor Serša, 2025, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: elektrokemoterapija, eksperimentalna onkologija, miši
Objavljeno v DiRROS: 11.03.2026; Ogledov: 322; Prenosov: 112
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6. Electrochemotherapy with bleomycin, oxaliplatin, or cisplatin in mouse tumor models, from tumor ablation to in situ vaccinationKatja Uršič Valentinuzzi, Urška Kamenšek, Simona Kranjc Brezar, Chloe Heranney, Tilen Komel, Simon Buček, Maja Čemažar, Gregor Serša, 2025, izvirni znanstveni članek Povzetek: Introduction: In addition to its direct cytotoxic effects, ablative therapies as electrochemotherapy (ECT) can elicit indirect antitumor effects by triggering immune system responses. Here, we comprehensively analyzed this dual effectiveness of intratumoral ECT with chemotherapeutic drugs bleomycin (BLM), oxaliplatin (OXA), and cisplatin (CDDP). Our aim was to determine if ECT can act as in situ vaccination and thereby induce an abscopal effect. By evaluating ECT’s potential for in situ vaccination, our goal was to pave the way for future advancements for its combination with emerging (immuno)therapies, leading to enhanced responses and outcomes. Methods: We employed two mouse tumor models, the immunologically cold B16F10 melanoma and 4T1 mammary carcinoma, to explore both local and systemic (i.e., abscopal) antitumor effects following equieffective intratumoral ECT with BLM, OXA, and CDDP. Through histological analyses and the use of immunodeficient and metastatic (for abscopal effect) mouse models, we identified and compared both the cytotoxic and immunological components of ECT’s antitumor efficiency, such as immunologically recognizable cell deaths (immunogenic cell death and necrosis) and immune infiltrate (CD11+, CD4+, CD8+, GrB+). Results: Differences in immunological involvement after equieffective intratumoral ECT were highlighted by variable kinetics of immunologically recognizable cell deaths and immune infiltrate across the studied tumor models. Particularly, the 4T1 tumor model exhibited a more pronounced involvement of the immune component compared to the B16F10 tumor model. Variances in the antitumor (immune) response were also detected based on the chemotherapeutic drug used in ECT. Collectively, ECT demonstrated effectiveness in inducing in situ vaccination in both tumor models; however, an abscopal effect was observed in the 4T1 tumor model only. Conclusions: This is the first preclinical study systematically comparing the immune involvement in intratumoral ECT’s efficiency using three distinct chemotherapeutic drugs in mouse tumor models. The demonstrated variability in immune response to ECT across different tumor models and chemotherapeutic drugs provides a basis for future investigations aimed at enhancing the effectiveness of combined treatments.
Ključne besede: electroporation, chemotherapeutic drugs, mouse tumor models
Objavljeno v DiRROS: 19.11.2025; Ogledov: 491; Prenosov: 251
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7. Electrotransfer of plasmid DNA radiosensitizes B16F10 tumors through activation of immune responseMonika Savarin, Urška Kamenšek, Maja Čemažar, Richard Heller, Gregor Serša, 2017, izvirni znanstveni članek Povzetek: Tumor irradiation combined with adjuvant treatments, either vascular targeted or immunomodulatory, is under intense investigation. Gene electrotransfer of therapeutic genes is one of these approaches. The aim of this study was to determine, whether gene electrotransfer of plasmid encoding shRNA for silencing endoglin, with vascular targeted effectiveness, can radiosensitize melanoma B16F10 tumors. Materials and methods. The murine melanoma B16F10 tumors, growing on the back of C57Bl/6 mice, were treated by triple gene electrotransfer and irradiation. The antitumor effect was evaluated by determination of tumor growth delay and proportion of tumor free mice. Furthermore, histological analysis of tumors (necrosis, apoptosis, proliferation, vascularization, presence of hypoxia and infiltration of immune cells,) was used to evaluate the therapeutic mechanisms. Results. Gene electrotransfer of plasmid silencing endoglin predominantly indicated vascular targeted effects of the therapy, since significant tumor growth delay and 44% of tumor free mice were obtained. In addition, irradiation had minor effects on radioresistant melanoma, with 11% of mice tumor free. The combined treatment resulted in excellent effectiveness with 88% of mice tumor free, with more than half resistant to secondary tumor challenge, which was observed also with the plasmid devoid of the therapeutic gene. Histological analysis of tumors in the combined treatment group, demonstrated similar mode of action of the gene electrotransfer of plasmid encoding shRNA for silencing endoglin and devoid of it, both through the induction of an immune response. Conclusions. The results of this study indicate that irradiation can in radioresistant melanoma tumors, by release of tumor associated antigens, serve as activator of the immune response, besides directly affecting tumor cells and vasculature. The primed antitumor immune response can be further boosted by gene electrotransfer of plasmid, regardless of presence of the therapeutic gene, which was confirmed by the high radiosensitization, resulting in prolonged tumor growth delay and 89% of tumor free mice that were up to 63% resistant to secondary challenge of tumor. In addition, gene electrotransfer of therapeutic plasmid for silencing endoglin has also a direct effect on tumor vasculature and tumors cells; however in combination with radiotherapy this effect was masked by pronounced immune response.
Ključne besede: gene therapy, electrotransfer, plasmid, irradiation, immune response, melanoma
Objavljeno v DiRROS: 24.05.2024; Ogledov: 1968; Prenosov: 645
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8. Adjuvant TNF-a therapy to electrochemotherapy with intravenous cisplatin in murine sarcoma exerts synergistic antitumor effectivenessMaja Čemažar, Vesna Todorović, Janez Ščančar, Urša Lampreht Tratar, Monika Savarin, Urška Kamenšek, Simona Kranjc Brezar, Andrej Cör, Gregor Serša, 2015, izvirni znanstveni članek Povzetek: Background. Electrochemotherapy is a tumour ablation modality, based on electroporation of the cell membrane, allowing non-permeant anticancer drugs to enter the cell, thus augmenting their cytotoxicity by orders of magnitude. In preclinical studies, bleomycin and cisplatin proved to be the most suitable for clinical use. Intravenous administration of cisplatin for electrochemotherapy is still not widely accepted in the clinics, presumably due to its lower antitumor effectiveness, but adjuvant therapy by immunomodulatory or vascular-targeting agents could provide a way for its potentiation. Hence, the aim of the present study was to explore the possibility of adjuvant tumour necrosis factor % (TNF-%) therapy to potentiate antitumor effectiveness of electrochemotherapy with intravenous cisplatin administration in murine sarcoma. Materials and methods. In vivo study was designed to evaluate the effect of TNF-% applied before or after the electrochemotherapy and to evaluate the effect of adjuvant TNF-% on electrochemotherapy with different cisplatin doses. Results. A synergistic interaction between TNF-% and electrochemotherapy was observed. Administration of TNF-% before the electrochemotherapy resulted in longer tumour growth delay and increased tumour curability, and was significantly more effective than TNF-% administration after the electrochemotherapy. Tumour analysis revealed increased platinum content in tumours, TNF-% induced blood vessel damage and increased tumour necrosis after combination of TNF-% and electrochemotherapy, indicating an anti-vascular action of TNF-%. In addition, immunomodulatory effect might have contributed to curability rate of the tumours. Conclusion. Adjuvant intratumoural TNF-% therapy synergistically contributes to electrochemotherapy with intravenous cisplatin administration. Due to its potentiation at all doses of cisplatin, the combined treatment is predicted to be effective also in tumours, where the drug concentration is suboptimal or in bigger tumours, where electrochemotherapy with intravenous cisplatin is not expected to be sufficiently effective.
Ključne besede: electrochemotherapy, TNF, adjuvant immunotherapy, cisplatin
Objavljeno v DiRROS: 17.04.2024; Ogledov: 1772; Prenosov: 524
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9. Gene immunotherapy of colon carcinoma with IL-2 and IL-12 using gene electrotransferTilen Komel, Maša Omerzel, Urška Kamenšek, Katarina Žnidar, Urša Lampreht Tratar, Simona Kranjc Brezar, Klemen Dolinar, Sergej Pirkmajer, Gregor Serša, Maja Čemažar, 2023, izvirni znanstveni članek Povzetek: Gene immunotherapy has become an important approach in the treatment of cancer. One example is the introduction of genes encoding immunostimulatory cytokines, such as interleukin 2 and interleukin 12, which stimulate immune cells in tumours. The aim of our study was to determine the effects of gene electrotransfer of plasmids encoding interleukin 2 and interleukin 12 individually and in combination in the CT26 murine colon carcinoma cell line in mice. In the in vitro experiment, the pulse protocol that resulted in the highest expression of IL-2 and IL-12 mRNA and proteins was used for the in vivo part. In vivo, tumour growth delay and also complete response were observed in the group treated with the plasmid combination. Compared to the control group, the highest levels of various immunostimulatory cytokines and increased immune infiltration were observed in the combination group. Long-term anti-tumour immunity was observed in the combination group after tumour re-challenge. In conclusion, our combination therapy efficiently eradicated CT26 colon carcinoma in mice and also generated strong anti-tumour immune memory.
Ključne besede: colon carcinoma, gene electrotransfer, gene immunotherapy
Objavljeno v DiRROS: 21.03.2024; Ogledov: 1791; Prenosov: 875
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10. Evaluation of shRNA-mediated gene silencing by electroporation in LPB fibrosarcoma cellsSuzana Vidic, Urška Kamenšek, Maja Čemažar, 2008, izvirni znanstveni članek Povzetek: Background. Silencing oncogenes or other genes that contribute to tumor malignancy and progression offers a promising approach to treating cancer. Specific and efficient silencing of gene expression can be achieved by RNA interference (RNAi) technology using small interfering RNA (siRNA) or short hairpin RNA (shRNA). However, a major challenge in RNAi technology is effective delivery of interfering molecules into target cells. The aim of our study was to evaluate electroporation as a perspective method for efficient invitro transfection of LPB fibrosarcoma cells with plasmid DNA expressing shRNA. Methods. Induction of shRNA-mediated gene silencing by electroporation was determined by fluorescence microscopy, flow cytometry and western blot analysis. The effect of electroporation conditions on cell survival and proliferation was determined by clonogenic assay. Results and conclusions. Ourresults demonstrated that electroporation is a feasible and effective method for delivery of plasmid DNA expressing shRNA into cancer cells in vitro. Electrotransfection of murine LPB fibrosarcoma cells, continuously expressing green fluorescence protein - GFP (LPBGFP), with plasmid DNA encoding shRNA-GFP, reduced GFP expression, which was determined on the protein level, as well as by measurement of GFP fluorescence intensity. A pronounced reduction in GFP expression level was detected from the second to the fifth day after treatment. Moreover, the method is easy to perform and showed low cell damaging effects, which are the most important and preferential factors for further in vivo studies.
Objavljeno v DiRROS: 08.03.2024; Ogledov: 1376; Prenosov: 373
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