ID: 2178

• Title:
  Gene electrotransfer of interleukin 12 to porcine skin: supportive data for human clinical trials
  
  Authors:
  

  Lampreht Tratar, Ursa - Institute of Oncology Ljubljana, Slovenia; Veterinary faculty, University of Ljubljana, Slovenia
  Jesenko, Tanja - Institute of Oncology Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Slovenia
  Bosnjak, Masa - Institute of Oncology Ljubljana, Slovenia
  Sersa, Gregor - Institute of Oncology Ljubljana, Slovenia
  Cemazar, Maja - Institute of Oncology Ljubljana, Slovenia; Faculty of Health Sciences, University of Primorska, Slovenia
  

  
  
  Abstract:
  Gene electrotransfer (GET) of plasmid encoding interleukin 12 (IL -12) has already been used in preclinical settings on mice as well as in clinical trials in human and veterinary oncology alona or in combination with electrochemotherapy. Although the combination therapy has proven to be effective, there is still a need for optimisation of the gene therapy to improve the treatment outcome. In particular, the optimisation concerns the different concentrations of plasmid DNA, the use of invasive or non-invasive electrodes and the use of plasmid DNA lacking the antibiotic resistance gene. In recent years, we have developed a plasmid that encodes human interleukin-12 (phIL12). It is currently in a phase I clinical trial involving patients with basal cell carcinoma of the head and neck (Clinicaltrials.gov: NCT05077033). The plasmid phIL12 is free of the antibiotic resistance gene and was therefore developed in accordance with the EMA guidelines for advanced therapy medicinal products. The plasmid has already been evaluated in a preclinical study in the mouse tumour model CT26, using a plasmid with a transcript for the mouse ortholog IL -12, which demonstrated its biological activity, safety, efficacy, pharmacokinetic and pharmacodynamic properties. The aim of this study was to investigate the use of different IL12 GET modalities (different plasmid DNA concentrations and use of invasive or non-invasive electrodes) on IL -12 expression in skin, as well as to confirm the pharmacokinetic properties of the plasmid phIL12 in another animal species. The pig model was chosen because IL -12 is biologically active in pigs and the skin characteristics of pigs, dogs and humans are similar. The study was approved by the National Animal Ethics Committee (U34401-2/2021/5). Gene transfer of phIL12 into the skin was performed on 9 pigs. Different concentrations of the plasmid phIL12 (0 mg/ml, 1 mg/ml and 2 mg/ml) and two different types of electrodes were used: Plate (non-invasive) and needle (invasive). The animals were euthanised 7, 14 and 28 days after GET. The expression of IL -12 in the skin was performed at the mRNA level by RT -qPCR and at the protein level by ELISA assay. Subsequently, the distribution of plasmid DNA in different organs and in the skin was examined by RT -qPCR. The results of our study showed that phIL12 GET with invasive electrodes induced higher expression of IL -12 at both protein and mRNA levels 7 days after GET compared to non-invasive electrodes. Plasmid DNA distribution showed the presence of plasmid in all tested samples with the highest plasmid copy number in the treated skin 7 days after GET. However, plasmid copy number decreased over time in all samples and was lowest 28 days after GET. The results of this study show that phIL12 is expressed in pig skin and has similar pharmacokinetic properties to the mouse orthologue.
  
  Keywords:
  gene electrotransfer; Interleukin 12, porcine model
  
  Refs:
  
  
  Topic 1:
  12. Biomedical applications
  
  Topic 2:
  6. Cancer treatment and tumor ablation