1. Chemokine CCL5 overexpression combined with radiotherapy modulates Th1-mediated immune response and leads to significant tumor growth delay in mouse tumor modelsTim Božič, Iva Šantek, Živa Pišljar, Simona Kranjc Brezar, Gregor Serša, Boštjan Markelc, Maja Čemažar, 2026, izvirni znanstveni članek Povzetek: This study investigated the antitumor efficacy of chemokine CCL5 gene therapy using gene electrotransfer (GET) in combination with radiotherapy (RT) in solid murine tumors CT26 and 4T1. In vitro, CT26 and 4T1 tumor cells transfected with plasmid DNA (pDNA) encoding CCL5 induced migration of RAW264.7 macrophages. In vivo, CCL5 overexpression achieved via GET of pDNA encoding CCL5 led to increased splenocyte infiltration in dorsal window chamber models. When combined with RT, GET of pDNA encoding CCL5 shifted the tumor cytokine profile toward a proinflammatory state, with elevated Ifn-γ, Cxcl9, Cxcl10, and Il-12α. Although CD8 + and CD4 + T cells were reduced post-treatment, due to radiation-induced cell death, the combination of GET of pDNA encoding CCL5 and RT significantly delayed tumor growth in both models. In 4T1 tumors, this delay was also significant compared to the equivalent treatment with GET of control pDNA. These findings support GET of pDNA encoding CCL5 combined with RT as a strategy to enhance immune-mediated tumor control.
Ključne besede: chemokines, gene electrotransfer, gene therapy, mouse, radiotherapy
Objavljeno v DiRROS: 13.02.2026; Ogledov: 33; Prenosov: 8
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4. Human papillomavirus-related oropharyngeal squamous cell carcinoma exhibits enhanced radiosensitivity despite limited activation of cytosolic DNA sensing pathways and innate immune responsesKristina Levpušček, Tanja Jesenko, Tilen Komel, Simona Kranjc Brezar, Gregor Serša, Maja Čemažar, Primož Strojan, 2025, izvirni znanstveni članek Povzetek: Pharyngeal squamous cell carcinoma (PSCC) is a significant health concern, with human papillomavirus 16 (HPV16) playing a key role in the etiology of oropharyngeal squamous cell carcinoma (OPSCC). HPV16-related OPSCC exhibits enhanced radiosensitivity compared to HPV16-unrelated PSCC, yet the underlying mechanisms remain poorly understood. As HPV16 oncoproteins E6 and E7 are known to interfere with innate immune signaling, we investigated how modulation of cytosolic DNA sensing pathways and innate immune responses changes after irradiation (IR) and whether this contributes to enhanced radiosensitivity in HPV16-related OPSCC. Materials and methods Using HPV16-related and -unrelated PSCC models, we examined baseline expression levels of DNA sensors and cytokines and assessed the effects of IR on double-stranded DNA (dsDNA) accumulation, activation of cytosolic DNA sensors, cytokines, and immune cell infiltration both in vitro and in vivo. Analyses were performed using real-time quantitative polymerase chain reaction (RT-qPCR) and immunofluorescent staining. Results HPV16-related OPSCC exhibited a distinct baseline expression profile of DNA sensors and cytokines, consistent with suppression of the stimulator of interferon genes (STING) pathway. While IR-induced activation of DNA sensors was dose- and time-dependent across models, HPV16-related OPSCC showed selective activation of cyclic GMP-AMP synthase (cGAS) and STING without significant cytokine upregulation or immune activation. In contrast, HPV16-related and unrelated PSCCs displayed activation of multiple DNA sensors, increased cytokine expression, and enhanced immune cell infiltration following IR. Conclusions The key finding was that the involvement of cytosolic DNA sensing pathways and innate immune system do not increase radiosensitivity of HPV16-related OPSCC. In PSCC models, DNA sensor and cytokine expression varied depending on IR dose and fractionation.
Ključne besede: human papillomavirus, oropharyngeal squamous cell carcinoma, radiosensitivity
Objavljeno v DiRROS: 16.01.2026; Ogledov: 139; Prenosov: 43
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5. Long-term outcomes of reduced-dose bleomycin in electrochemotherapy for basal cell carcinoma in elderly patientsAleš Grošelj, Črt Jamšek, Simona Kranjc Brezar, Maja Čemažar, Maša Omerzel, Luka Pušnik, Gregor Serša, 2025, izvirni znanstveni članek Povzetek: Electrochemotherapy (ECT) is a minimally invasive treatment option for basal cell carcinoma (BCC), which is particularly advantageous in the elderly population. This study evaluated the long-term effects of treating BCC in older patients using ECT with a reduced dose of bleomycin (10,000 IU/m2) and compared the results to patients who received the standard dose of bleomycin (15,000 IU/m2). The retrospective analysis included 116 patients aged over 65 years with 257 histologically confirmed BCCs. Tumors were treated with either the standard dose (n = 82) or the reduced dose (n = 175) of bleomycin. The results showed that the recurrence rate was comparable between the groups, particularly in the first year after treatment. The reduced-dose group exhibited a greater recurrence rate after the first year, which may be attributed to a weaker local immune response due to the de-escalated dose of bleomycin. Nonetheless, administering a standard bleomycin dosage as a salvage treatment in the event of recurrence proved highly effective. These findings suggest that ECT with a reduced bleomycin dose is a viable option for treating BCC in elderly patients, particularly those with shorter life expectancy.
Ključne besede: bleomycin, electrochemotherapy, head and neck, nonmelanoma skin cancer
Objavljeno v DiRROS: 25.11.2025; Ogledov: 498; Prenosov: 172
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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: 280; Prenosov: 138
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7. Muscle gene electrotransfer is increased by the antioxidant tempol in miceBoštjan Markelc, Gregor Tevž, Maja Čemažar, Simona Kranjc Brezar, Jaka Lavrenčak, Bojana Žegura, Justin Teissié, Gregor Serša, 2012, izvirni znanstveni članek Povzetek: Electropermeabilization (EP) is an effective method of gene transfer into different tissues. During EP, reactive oxygen species (ROS) are formed, which could affect transfection efficiency. The role of generated ROS and the role of antioxidants in electrotransfer in myoblasts in vitro and in Musculus tibialis cranialis in mice were, therefore, investigated. We demonstrate in the study that during EP of C2C12 myoblasts, ROS are generated on the surface of the cells, which do not induce long-term genomic DNA damage. Plasmid DNA for transfection (pEGFP-N1), which is present outside the cells during EP, neutralizes the generated ROS. The ROS generation is proportional to the amplitude of the electric pulses and can be scavenged by antioxidants, such as vitamin C or tempol. When antioxidants were used during gene electrotransfer, the transfection efficiency of C2C12 myoblasts was statistically significantly increased 1.6-fold with tempol. Also in vivo, the transfection efficiency of M. tibialis cranialis in mice was statistically significantly increased 1.4-fold by tempol. The study indicates that ROS are generated on cells during EP and can be scavenged by antioxidants. Specifically, tempol can be used to improve gene electrotransfer into the muscle and possibly also to other tissues.
Ključne besede: electropermeabilization, gene electrotransfer, muscle, tempol, reactive oxygen species
Objavljeno v DiRROS: 26.02.2025; Ogledov: 829; Prenosov: 450
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8. Cannabinoids and triple-negative breast cancer treatmentLuka Dobovišek, Simona Borštnar, Nataša Debeljak, Simona Kranjc Brezar, 2024, pregledni znanstveni članek Povzetek: Triple-negative breast cancer (TNBC) accounts for about 10-20% of all breast cancer cases and is associated with an unfavorable prognosis. Until recently, treatment options for TNBC were limited to chemotherapy. A new successful systemic treatment is immunotherapy with immune checkpoint inhibitors, but new tumor-specific biomarkers are needed to improve patient outcomes. Cannabinoids show antitumor activity in most preclinical studies in TNBC models and do not appear to have adverse effects on chemotherapy. Clinical data are needed to evaluate efficacy and safety in humans. Importantly, the endocannabinoid system is linked to the immune system and immunosuppression. Therefore, cannabinoid receptors could be a potential biomarker for immune checkpoint inhibitor therapy or a novel mechanism to reverse resistance to immunotherapy. In this article, we provide an overview of the currently available information on how cannabinoids may influence standard therapy in TNBC.
Ključne besede: triple-negative breast cancer, breast cancer, cancer treatment, cannabinoids
Objavljeno v DiRROS: 18.09.2024; Ogledov: 1082; Prenosov: 561
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9. Addition of 2-(ethylamino)acetonitrile group to nitroxoline results in significantly improved anti-tumor activity in vitro and in vivoAna Mitrović, Izidor Sosič, Špela Kos, Urša Lampreht Tratar, Barbara Breznik, Simona Kranjc Brezar, Bojana Mirković, Stanislav Gobec, Tamara Lah Turnšek, Maja Čemažar, Gregor Serša, Janko Kos, 2017, izvirni znanstveni članek Povzetek: Lysosomal cysteine peptidase cathepsin B, involved in multiple processes associated with tumor progression, is validated as a target for anti-cancer therapy. Nitroxoline, a known antimicrobial agent, is a potent and selective inhibitor of cathepsin B, hence reducing tumor progression in vitro and in vivo. In order to further improve its anti-cancer properties we developed a number of derivatives using structure-based chemical synthesis. Of these, the 7-aminomethylated derivative (compound 17) exhibited significantly improved kinetic properties over nitroxoline, inhibiting cathepsin B endopeptidase activity selectively. In the present study, we have evaluated its anti-cancer properties. It was more effective than nitroxoline in reducing tumor cell invasion and migration, as determined in vitro on two-dimensional cell models and tumor spheroids, under either endpoint or real time conditions. Moreover, it exhibited improved action over nitroxoline in impairing tumor growth in vivo in LPB mouse fibrosarcoma tumors in C57Bl/6 mice. Taken together, the addition of a 2-(ethylamino)acetonitrile group to nitroxoline at position 7 significantly improves its pharmacological characteristics and its potential for use as an anti-cancer drug.
Ključne besede: nitroxoline derivative, cathepsin B, inhibition, tumor invasion, cell migration
Objavljeno v DiRROS: 26.07.2024; Ogledov: 1070; Prenosov: 762
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10. Improved protective effect of umbilical cord stem cell transplantation on cisplatin-induced kidney injury in mice pretreated with antithymocyte globulinŽeljka Večerić-Haler, Andreja Erman, Anton Cerar, Helena Motaln, Katja Kološa, Tamara Lah Turnšek, Snežna Sodin-Šemrl, Katja Lakota, Katjuša Mrak Poljšak, Špela Škrajnar, Simona Kranjc Brezar, Miha Arnol, Martina Perše, 2016, izvirni znanstveni članek Povzetek: Mesenchymal stem cells (MSCs) are recognised as a promising tool to improve renal recovery in experimental models of cisplatin-induced acute kidney injury. However, these preclinical studies were performed on severely immunodeficient animals. Here, we investigated whether human umbilical cord derived MSC treatment could equally ameliorate acute kidney injury induced by cisplatin and prolong survival in mice with a normal immune system and those with a suppressed immune system by polyclonal antithymocyte globulin (ATG). We demonstrated that ATG pretreatment, when followed by MSC transplantation, significantly improved injured renal function parameters, as evidenced by decreased blood urea nitrogen and serum creatinine concentration, as well as improved renal morphology. This tissue restoration was also supported by increased survival of mice. The beneficial effects of ATG were associated with reduced level of inflammatory protein serum amyloid A3 and induced antioxidative expression of superoxide dismutase-1 (SOD-1), glutathione peroxidase (GPx), and hem oxygenase-1 (HO-1). Infused MSCs became localised predominantly in peritubular areas and acted to reduce renal cell death. In conclusion, these results show that ATG diminished in situ inflammation and oxidative stress associated with cisplatin-induced acute kidney injury, the effects that may provide more favourable microenvironment for MSC action, with consequential synergistic improvements in renal injury and animal survival as compared to MSC treatment alone.
Ključne besede: mesenchymal stem cells, nephrotoxicity
Objavljeno v DiRROS: 25.07.2024; Ogledov: 978; Prenosov: 746
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