CAR Gene Delivery by T‐cell Targeted Lentiviral Vectors is Enhanced by Rapamycin Induced Reduction of Antiviral Mechanisms

• Published in: Advanced science Vol. 10; no. 35; pp. e2302992 - n/a
• Main Authors: Charitidis, Filippos T, Adabi, Elham, Ho, Naphang, Braun, Angela H, Tierney, Ciara, Strasser, Lisa, Thalheimer, Frederic B, Childs, Liam, Bones, Jonathan, Clarke, Colin, Buchholz, Christian J
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 01.12.2023; John Wiley and Sons Inc; Wiley
• Subjects: CAR T cells; Cells; Gene expression; Gene therapy; Genetic engineering; IFITM; in vivo gene delivery; Lymphocytes; Proteins; rapamycin; receptor‐targeted vectors; scRNA‐seq; transduction enhancer; Vectors (Biology); Viral infections; Viruses; IFITM; scRNA-seq; in vivo gene delivery; CAR T cells; transduction enhancer; receptor-targeted vectors; rapamycin
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202302992

Lentiviral vectors (LV) have become the dominant tool for stable gene transfer into lymphocytes including chimeric antigen receptor (CAR) gene delivery to T cells, a major breakthrough in cancer therapy. Yet, room for improvement remains, especially for the latest LV generations delivering genes selectively into T cell subtypes, a key requirement for in vivo CAR T cell generation. Toward improving gene transfer rates with these vectors, whole transcriptome analyses on human T lymphocytes are conducted after exposure to CAR‐encoding conventional vectors (VSV‐LV) and vectors targeted to CD8+ (CD8‐LV) or CD4+ T cells (CD4‐LV). Genes related to quiescence and antiviral restriction are found to be upregulated in CAR‐negative cells exposed to all types of LVs. Down‐modulation of various antiviral restriction factors, including the interferon‐induced transmembrane proteins (IFITMs) is achieved with rapamycin as verified by mass spectrometry (LC‐MS). Strikingly, rapamycin enhances transduction by up to 7‐fold for CD8‐LV and CD4‐LV without compromising CAR T cell activities but does not improve VSV‐LV. When administered to humanized mice, CD8‐LV results in higher rates of green fluorescent protein (GFP) gene delivery. Also in vivo CAR T cell generation is improved in kinetics and tumor control, however to a moderate extent, leaving room for improvement by optimizing the rapamycin administration schedule. The data favor multi‐omics approaches for improvements in gene delivery. The work highlights the benefit of single‐cell‐based monitoring approaches for the identification of restriction factors inhibiting lentiviral‐vector‐mediated transduction. By downmodulating those factors both, conventional and in vivo CAR T cell generation by T‐cell targeted vectors can be improved.