In vitro exploration of a myeloid-derived suppressor cell line as vehicle for cancer gene therapy

• Published in: Cancer gene therapy 2017-04, Vol.24 (4), p.149-155
• Main Authors: Denies, S, Combes, F, Ghekiere, C, Mc Cafferty, S, Cicchelero, L, Sanders, N N
• Format: Article
• Language: English
• Subjects: 631/1647/2300/1851; 631/67/327; Animals; Antineoplastic antibiotics; Apoptosis; Biomedical and Life Sciences; Biomedicine; Cancer; Care and treatment; CD80 antigen; Cell death; Cell Line; Cell migration; Cell viability; Deoxyribonucleic acid; DNA; Dosage and administration; Electroporation; Gene Expression; Gene Therapy; Genetic aspects; Genetic Therapy - methods; Health aspects; Interleukin 12; Interleukin-12 - genetics; Interleukin-12 - immunology; Intracellular; Mice; Myeloid Cells - immunology; Neoplasms - genetics; Neoplasms - immunology; Neoplasms - therapy; original-article; Plasmids; Stem cells; Suppressor cells; Transfection; Tumor cells
• ISSN: 0929-1903; 1476-5500
• DOI: 10.1038/cgt.2016.60

Recent research indicates that cell-mediated gene therapy can be an interesting method to obtain intratumoral expression of therapeutic proteins. This paper explores the possibility of using transfected myeloid-derived suppressor cells (MDSCs), derived from a murine cell line, as cellular vehicles for transporting plasmid DNA (pDNA) encoding interleukin-12 (IL-12) to tumors. Transfecting these cells via electroporation caused massive cell death. This was not due to electroporation-induced cell damage, but was mainly the result of the intracellular presence of plasmids. In contrast, pDNA transfection using Lipofectamine 2000 (LF2000) did not result in a significant loss of viability. Differences in delivery mechanism may explain the distinctive effects on cell viability. Indeed, electroporation is expected to cause a rapid and massive influx of pDNA resulting in cytosolic pDNA levels that most likely surpass the activation threshold of the intracellular DNA sensors leading to cell death. In contrast, a more sustained intracellular release of the pDNA is expected with LF2000. After lipofection with LF2000, 56% of the MDSCs were transfected and transgene expression lasted for at least 24 h. Moreover, biologically relevant amounts of IL-12 were produced by the MDSCs after lipofection with an IL-12 encoding pDNA. In addition, IL-12 transfection caused a significant upregulation of CD80 and considerably reduced the immunosuppressive capacity of the MDSCs. IL-12-transfected MDSCs were still able to migrate to tumor cells, albeit that lipofection of the MDSCs seemed to slightly decrease their migration capacity.