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Query: "author" (Maja Čemažar) .

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1.
Safety and efficacy of IL-12 plasmid DNA transfection into pig skin : supportive data for human clinical trials on gene therapy and vaccination
Urša Lampreht Tratar, Tanja Jesenko, Maša Omerzel, Alenka Seliškar, Urban Stupan, Mihajlo Djokić, Jerneja Sredenšek, Blaž Trotovšek, Gregor Serša, Maja Čemažar, 2024, original scientific article

Abstract: Gene electrotransfer (GET) of plasmids encoding interleukin 12 (IL-12) has already been used for the treatment of various types of tumors in human oncology and as an adjuvant in DNA vaccines. In recent years, we have developed a plasmid encoding human IL-12 (phIL12) that is currently in a phase I clinical study. The aim was to confirm the results of a non-clinical study in mice on pharmacokinetic characteristics and safety in a porcine model that better resembled human skin. The GET of phIL12 in the skin was performed on nine pigs using different concentrations of plasmid phIL12 and invasive (needle) or noninvasive (plate) types of electrodes. The results of our study demonstrate that the GET of phIL-12 with needle electrodes induced the highest expression of IL-12 at the protein level on day 7 after the procedure. The plasmid was distributed to all tested organs; however, its amount decreased over time and was at a minimum 28 days after GET. Based on plasmid copy number and expression results, together with blood analysis, we showed that IL-12 GET is safe in a porcine animal model. Furthermore, we demonstrated that pigs are a valuable model for human gene therapy safety studies.
Keywords: interleukin 12, gene electrotransfer, immunotherapy
Published in DiRROS: 18.04.2024; Views: 18; Downloads: 12
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2.
Adjuvant TNF-a therapy to electrochemotherapy with intravenous cisplatin in murine sarcoma exerts synergistic antitumor effectiveness
Maja Čemažar, Vesna Todorović, Janez Ščančar, Urša Lampreht Tratar, Monika Savarin, Urška Kamenšek, Simona Kranjc Brezar, Andrej Cör, Gregor Serša, 2015, original scientific article

Abstract: 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.
Keywords: electrochemotherapy, TNF, adjuvant immunotherapy, cisplatin
Published in DiRROS: 17.04.2024; Views: 46; Downloads: 5
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3.
Effect of ionizing radiation on human skeletal muscle precursor cells
Mihaela Jurdana, Maja Čemažar, Katarina Pegan, Tomaž Marš, 2013, published scientific conference contribution

Abstract: Background. Long term effects of different doses of ionizing radiation on human skeletal muscle myoblast proliferation, cytokine signalling and stress response capacity were studied in primary cell cultures.Materials and methods. Human skeletal muscle myoblasts obtained from muscle biopsies were cultured and irradiated with a Darpac 2000 X-ray unit at doses of 4, 6 and 8 Gy. Acute effects of radiation were studied by interleukin - 6 (IL-6) release and stress response detected by the heat shock protein (HSP) level, while long term effects were followed by proliferation capacity and cell death.Results. Compared with non-irradiated control and cells treated with inhibitor of cell proliferation Ara C, myoblast proliferation decreased 72 h post-irradiation, this effect was more pronounced with increasing doses. Post-irradiation myoblast survival determined by measurement of released LDH enzyme activity revealed increased activity after exposure to irradiation. The acute response of myoblasts to lower doses of irradiation (4 and 6 Gy) was decreased secretion of constitutive IL-6. Higher doses of irradiation triggered a stress response in myoblasts, determined by increased levels of stress markers (HSPs 27 and 70).Conclusions. Our results show that myoblasts are sensitive to irradiation in terms of their proliferation capacity and capacity to secret IL-6. Since myoblast proliferation and differentiation are a key stage in muscle regeneration, this effect of irradiation needs to be taken in account, particularly in certain clinical conditions.
Keywords: myoblasts, irradiation, proliferation, interleukin 6, muscle regeneration, apoptosis
Published in DiRROS: 03.04.2024; Views: 65; Downloads: 29
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Assessment of the tumourigenic and metastatic properties of SK-MEL28 melanoma cells surviving electrochemotherapy with bleomycin
Vesna Todorović, Gregor Serša, Vid Mlakar, Damjan Glavač, Maja Čemažar, 2012, original scientific article

Abstract: 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.
Published in DiRROS: 21.03.2024; Views: 276; Downloads: 43
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6.
Effects of electrochemotherapy on immunologically important modifications in tumor cells
Urša Kešar, Boštjan Markelc, Tanja Jesenko, Katja Uršič Valentinuzzi, Maja Čemažar, Primož Strojan, Gregor Serša, 2023, original scientific article

Abstract: Electrochemotherapy (ECT) is a clinically acknowledged method that combines the use of anticancer drugs and electrical pulses. Electrochemotherapy with bleomycin (BLM) can induce immunogenic cell death (ICD) in certain settings. However, whether this is ubiquitous over different cancer types and for other clinically relevant chemotherapeutics used with electrochemotherapy is unknown. Here, we evaluated in vitro in the B16-F10, 4T1 and CT26 murine tumor cell lines, the electrochemotherapy triggered changes in the ICD-associated damage-associated molecular patterns (DAMPs): Calreticulin (CRT), ATP, High Mobility Group Box 1 (HMGB1), and four immunologically important cellular markers: MHCI, MHC II, PD-L1 and CD40. The changes in these markers were investigated in time up to 48 h after ECT. We showed that electrochemotherapy with all three tested chemotherapeutics induced ICD-associated DAMPs, but the induced DAMP signature was cell line and chemotherapeutic concentration specific. Similarly, electrochemotherapy with CDDP, OXA or BLM modified the expression of MHC I, MHC II, PD-L1 and CD40. The potential of electrochemotherapy to change their expression was also cell line and chemotherapeutic concentration specific. Our results thus put the electrochemotherapy with clinically relevant chemotherapeutics CDDP, OXA and BLM on the map of ICD inducing therapies.
Keywords: electrochemotherapy, cisplatin, immune response
Published in DiRROS: 21.03.2024; Views: 74; Downloads: 40
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7.
Gene immunotherapy of colon carcinoma with IL-2 and IL-12 using gene electrotransfer
Tilen Komel, Maša Omerzel, Urška Kamenšek, Katarina Žnidar, Urša Lampreht Tratar, Simona Kranjc Brezar, Klemen Dolinar, Sergej Pirkmajer, Gregor Serša, Maja Čemažar, 2023, original scientific article

Abstract: 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.
Keywords: colon carcinoma, gene electrotransfer, gene immunotherapy
Published in DiRROS: 21.03.2024; Views: 95; Downloads: 47
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8.
The prognostic and predictive value of human gastrointestinal microbiome and exosomal mRNA expression of PD-L1 and IFNγ for immune checkpoint inhibitors response in metastatic melanoma patients : protocol trial
Ana Erman, Marija Ignjatović, Katja Leskovšek, Simona Miceska, Urša Lampreht Tratar, Maša Omerzel, Veronika Kloboves-Prevodnik, Maja Čemažar, Lidija Kandolf Sekulović, Gorazd Avguštin, Janja Ocvirk, Tanja Mesti, 2023, original scientific article

Abstract: Background: Immunotherapy has been successful in treating advanced melanoma, but a large proportion of patients do not respond to the treatment with immune checkpoint inhibitors (ICIs). Preclinical and small cohort studies suggest gastrointestinal microbiome composition and exosomal mRNA expression of PD-L1 and IFNγ from the primary tumor, stool and body fluids as potential biomarkers for response. Methods: Patients treated with immune checkpoint inhibitors as a first line treatment for metastatic melanoma are recruted to this prospective study. Stool samples are submitted before the start of treatment, at the 12th (+/−2) week and 28th (+/−2) week, and at the occurrence of event (suspected disease progression/hyperprogression, immune-related adverse event (irAE), deterioration). Peripheral venous blood samples are taken additionally at the same time points for cytologic and molecular tests. Histological material from the tumor tissue is obtained before the start of immunotherapy treatment. Primary objectives are to determine whether the human gastrointestinal microbiome (bacterial and viral) and the exosomal mRNA expression of PD-L1 and IFNγ and its dynamics predicts the response to treatment with PD-1 and CTLA-4 inhibitors and its association with the occurrence of irAE. The response is evaluated radiologically with imaging methods in accordance with the irRECIST criteria. Conclusions: This is the first study to combine and investigate multiple potential predictive and prognostic biomarkers and their dynamics in first line ICI in metastatic melanoma patients.
Keywords: gastrointestinal microbiome, mRNA expression of PD-L1 and IFNγ, immune checkpoint inhibitors, metastatic melanoma
Published in DiRROS: 21.03.2024; Views: 71; Downloads: 36
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