Abstract 353: How highly purified lentiviral vectors matter when it comes to genetically modifying your cells for the generation of in vitro or in vivo predictive cancer models
Authors: Georges Adriana , Gayon Régis , Duthoit Christine , Moal Yohann , Sevrain Raphael , Martin Nicolas , Bouillé Pascale 
Published: May 2015

Abstract
The development of relevant predictive cancer models including genetic modification is crucial for gene target validation and the assessment of molecules efficacy. Such models must be conceived through the use of a tool ensuring both the original phenotype of the cells to be strictly maintained and a stable expression of the sequence of interest in all target cells including primary cells. In these delicate cells as hematopoietic lineages, classical transfection protocols are not only transient and inefficient but they also induce cytotoxic effects and/or proliferative arrests. Gene transfer using lentiviral vectors is safer for such cells and the expression of the sequence of interest (cDNA, shRNA, miRNA) is stable thanks to the vector DNA integration into genomic DNA, bringing stable cell line at once. Using highly purified and concentrated lentivectors, we show that not only is it possible to transduce 100% of T lymphocytes, monocytes, M1/M2 Macrophages, and dendritic cells, but we also manage the integrated copy number and level of expression. With such transduction efficiency, it doesn’t worth to perform any antibiotic selection, allowing to save time and ensuring to keep the cells phenotype. In vivo, we show that lentiviral vectors expressing luciferase or fluorescent reporters are a good tool for noninvasive analyses of tumor animal models. They can be efficiently used through direct injections into adult animals and also through in vitro transductions of any tumoral cells subsequently reimplantated in the context of cancer models. The transplantation of genetically modified HSC offers an attractive alternative to transgenic animal models, allowing a more rapid and cost-effective in vivo validation of target genes for models of hematopoietic malignancies. Here, we present data obtained using concentrated and purified lentiviral suspension for the transduction of Lin- bone marrow cells before their transfer into recipient irradiated mice. These data bring out that lentiviral vectors have to be highly concentrated and purified in order to maintain the original cell phenotype, proliferation and viability in the goal to achieve an effective transgene expression. These two additional criterias combined with the lentiviral vector properties are required to ensure the development of trustworthy predictive cancer models, and thus build the link between in vitro assays and in vivo results to finally translate to therapeutic applications.
Citation Format: Adriana Georges, Régis Gayon, Christine Duthoit, Yohann Moal, Raphael Sevrain, Nicolas Martin, Pascale Bouillé. How highly purified lentiviral vectors matter when it comes to genetically modifying your cells for the generation of in vitro or in vivo predictive cancer models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 353. doi:10.1158/1538-7445.AM2014-353