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Povzetek: Interleukin 12 (IL-12) is a cytokine used as a therapeutic molecule in cancer immunotherapy. Gene electrotransfer mediated delivery of IL-12 gene has reached clinical evaluation in the USA using a plasmid that in addition to IL- 12 gene also carry an antibiotic resistance gene needed for its production in bacteria. In Europe however, Eu- ropean Medicines Agency recommends against the use of antibiotics during the production of clinical grade plasmids. We have prepared several antibiotic resistance gene-free plasmids using an antibiotic-free selection strategy called operator-repressor titration, including plasmids encoding mouse, canine and human IL-12 orthologues. The aim of this study was to evaluate the maintenance of these plasmids in bacterial culture and test their transfection efficiency using gene electrotransfer. Plasmid maintenance was evaluated by determining plasmid yields and topologies after subculturing transformed bacteria. Transfection efficiency was evaluated by determining the plasmid copy number, expression and cytotoxicity after gene electrotransfer to mouse, canine and human melanoma cells. The results demonstrated that our IL-12 plasmids without an antibiotic resistance gene are stably maintained in bacteria and provide sufficient IL-12 expression after in vitro gene electrotransfer; therefore, they have the potential to proceed to further in vivo evaluation studies.
Ključne besede: electrotransfer, interleukin-12, immunotherapy, mammals
Objavljeno v DiRROS: 23.09.2022; Ogledov: 561; Prenosov: 260
Celotno besedilo (2,13 MB)
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Povzetek: Electrochemotherapy (ECT) exhibits high therapeutic effectiveness in the clinic, achieving up to 80% local tumor control but without a systemic (abscopal) effect. Therefore, we designed a combination therapy consisting of ECT via intratumoral application of bleomycin, oxaliplatin or cisplatin with peritumoral gene electrotransfer of a plasmid encoding interleukin-12 (p. t. IL-12 GET). Our hypothesis was that p. t. IL-12 GET potentiates the effect of ECT on local and systemic levels and that the potentiation varies depending on tumor immune status. Therefore, the combination therapy was tested in three immunologically different murine tumor models. In poorly immunogenic B16F10 melanoma, IL-12 potentiated the antitumor effect of ECT with biologically equivalent low doses of cisplatin, oxaliplatin or bleomycin. The most pronounced potentiation was observed after ECT using cisplatin, resulting in a complete response rate of 38% and an abscopal effect. Compared to B16F10 melanoma, better responsiveness to ECT was observed in more immunogenic 4%T1 mammary carcinoma and CT26 colorectal carcinoma. In both models, p. t. IL-12 GET did not significantly improve the therapeutic outcome of ECT using any of the chemotherapeutic drugs. Collectively, the effectiveness of the combination therapy depends on tumor immune status. ECT was more effective in more immunogenic tumors, but GET exhibited greater contribution in less immunogenic tumors. Thus, the selection of the therapy, namely, either ECT alone or combination therapy with p. t. IL-12, should be predominantly based on tumor immune status.
Ključne besede: electrochemotherapy, gene electrotransfer, interleukin-12
Objavljeno v DiRROS: 21.09.2022; Ogledov: 563; Prenosov: 196
Celotno besedilo (7,82 MB)

Povzetek: Electrochemotherapy (ECT), a local therapy, has different effectiveness among tumor types. In breast can-cer, its effectiveness is low; therefore, combined therapies are needed. The aim of our study was to com-bine ECT with PARP inhibitor olaparib, which could inhibit the repair of bleomycin or cisplatin inducedDNA damage and potentiate the effectiveness of ECT. The effects of combined therapy were studied inBRCA1mutated (HCC1937) and non-mutated (HCC1143) triple negative breast cancer cell lines.Therapeutic effectiveness was studied in 2D and 3D cell cultures andin vivoon subcutaneousHCC1937 tumor model in mice. The underlying mechanism of combined therapy was determined withthe evaluation ofcH2AX foci. Combined therapy of ECT with bleomycin and olaparib potentiated theeffectiveness of ECT inBRCA1mutated HCC1937, but not in non-mutated HCC1143 cells. The combinedtherapy had a synergistic effect, which was due to the increased number of DNA double strand breaks.Addition of olaparib to ECT with bleomycinin vivoin HCC1937 tumor model had only minimal effect,indicating repetitive olaparib treatment would be needed. This study demonstrates that DNA repar inhibiting drugs, like olaparib, have the potential to increase the effectiveness of ECT with bleomycin.
Ključne besede: electrochemotherapy, breast cancer, olaparib, bleomycin
Objavljeno v DiRROS: 21.09.2022; Ogledov: 515; Prenosov: 179
Celotno besedilo (3,74 MB)

Povzetek: The effectiveness of immunotherapy highly correlates with the degree and the type of infiltrated immune cells in the tumor tissue. Treatments based on modifying the immune cell infiltrate of the tumor microenvironment are thus gaining momentum. Therefore, the aim of our study was to investigate the effects of gene therapy with two proinflammatory chemokines CCL5 and CCL17 on inflammatory cytokine expression profile and immune cell infiltrate in two murine breast tumor models, 4T1 and E0771, and two murine colon tumor models, CT26 and MC38. In vitro, lipofection of plasmid DNA encoding CCL5 or CCL17 resulted in changes in the cytokine expression profile similar to control plasmid DNA, implying that the main driver of these changes was the entry of foreign DNA into the cell%s cytosol. In vivo, gene electrotransfer resulted in high expression levels of both Ccl5 and Ccl17 transgenes in the 4T1 and CT26 tumor models. Besides a minor increase in the survival of the treated mice, the therapy also resulted in increased expression of Cxcl9 and Ifn%, potent activators of the immune system, in CT26 tumors. However, this was not recapitulated in changes of TME, implying that a further refinement of the dosing schedule is needed.
Ključne besede: chemokines, cytokine expression, gene electrotransfer, CCL5
Objavljeno v DiRROS: 19.09.2022; Ogledov: 524; Prenosov: 156
Celotno besedilo (5,63 MB)

Povzetek: Skin, the largest organ in the body, provides a passive physical barrier against infection and contains elements of the innate and adaptive immune systems. Skin consists of various cells, including keratinocytes, fibroblasts, endothelial cells and immune cells. This diversity of cell types could be important to gene therapies because DNA transfection could elicit different responses in different cell types. Previously, we observed the upregulation and activation of cytosolic DNA sensing pathways in several non-tumor and tumor cell types as well in tumors after the electroporation (electrotransfer) of plasmid DNA (pDNA). Based on this research and the innate immuno- genicity of skin, we correlated the effects of pDNA electrotransfer to fibroblasts and keratinocytes to mouse skin using reverse transcription real-time PCR (RT-qPCR) and several types of protein quantification. After pDNA electrotransfer, the mRNAs of the putative DNA sensors DEAD (AspGlu-Ala-Asp) box polypeptide 60 (Ddx60), absent in melanoma 2 (Aim2), Z-DNA binding protein 1 (Zbp1), interferon activated gene 202 (Ifi202), and interferon-inducible protein 204 (Ifi204) were upregulated in keratinocytes, while Ddx60, Zbp1 and Ifi204 were upregulated in fibroblasts. Increased levels of the mRNAs and proteins of several cytokines and chemokines were detected and varied based on cell type. Mouse skin experiments in vivo confirmed our in vitro results with increased expression of putative DNA sensor mRNAs and of the mRNAs and proteins of several cytokines and chemokines.
Ključne besede: DNA sensors, cytokines, electrotransfer, skin
Objavljeno v DiRROS: 06.09.2022; Ogledov: 575; Prenosov: 296
Celotno besedilo (7,72 MB)
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