Abstract 3246: Novel luciferase labelling technique to improve imaging of orthotopic prostate and pancreatic cancer models

Bioluminescent-labelling allows sensitive non-invasive sequential imaging of tumor development and early metastasis. However, current methods for the genetic modification of cells typically use integrating genotoxic viruses that can potentially disrupt the molecular behavior of cancer cell lines due to their random nature of integration. Here, we utilized a non-viral DNA vector that comprises an S/MAR (Scaffold/Matrix Attachment Region) element to stably modify cells to be further used in xenograft studies to allow long term expression without affecting cell behavior or silencing over cell divisions. Human PC-3 prostate cancer cells and BxPC-3 pancreatic cancer cells were stably transfected with a pCAG-LUC-S/MAR and cultured for 4 weeks under selection. Colonies that formed after this period were isolated and expanded in normal medium and evaluated for luciferase expression and molecular integrity of the DNA vector. For in vivo studies, PC-3 cells were inoculated orthotopically into the prostate, and BxPC-3 cells into the pancreas using athymic and BALB/c nude mice. For comparison, similar experiments with the corresponding study designs were performed with the non-labelled parental cell lines. The luciferase transfected cells maintained their original properties with stable expression. Luciferase-labelled PC-3 and BxPC-3 cells inoculated orthotopically into the prostate and pancreas, respectively, were successfully followed for 5 weeks with non-invasive bioluminescence imaging by IVIS. The results demonstrated high-quality follow-up of tumor growth compared with tumor models using non-labelled cells. In conclusion, S/MAR DNA vectors are able to produce genetically modified cells without the limitations of random genomic integration, whilst providing extra-chromosomal mitotic stability and sustained transgene expression at high level. When utilized in orthotopic xenograft studies, these luciferase expressing cells formed a reliable and essential non-invasive imaging platform that improves substantially efficacy testing of anticancer drug candidates. Citation Format: Jenni Bernoulli, Johanna Tuomela, Matthias Bozza, Katja M. Fagerlund, Mari I. Suominen, George Morris, Jussi M. Halleen, Richard Harbottle. Novel luciferase labelling technique to improve imaging of orthotopic prostate and pancreatic cancer models. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3246. doi:10.1158/1538-7445.AM2015-3246