Lentiviral delivery of combinatorial CAR/CRISPRi circuit into human primary T cells is enhanced by TBK1/IKKɛ complex inhibitor BX795

• Main Authors: Lingyu Li, Yuan Gao, Richa Srivastava, Wei Wang, Qinghui Xiong, Zhiming Fang, Alejandra Pelayo, Carolyn Denson, Angshumala Goswami, Rona Harari-Steinfeld, Zhifen Yang, Lihong Weng, Lei Stanley Qi, Francesco M. Marincola
• Format: Article
• Language: English
• Published: BMC 2020-09-01
• Series: Journal of Translational Medicine
• Subjects: BX795; Lentiviral transduction; T cell engineering; CAR-T; CRISPRi
• Online Access: http://link.springer.com/article/10.1186/s12967-020-02526-2

Abstract Background Adoptive transfer of engineered immune cells is a promising strategy for cancer treatment. However, low transduction efficiency particularly when large payload lentiviral vectors are used on primary T cells is a limitation for the development of cell therapy platforms that include multiple constructs bearing long DNA sequences. RB-340-1 is a new CAR T cell that combines two strategies in one product through a CRISPR interference (CRISPRi) circuit. Because multiple regulatory components are included in the circuit, RB-340-1 production needs delivery of two lentiviral vectors into human primary T cells, both containing long DNA sequences. To improve lentiviral transduction efficiency, we looked for inhibitors of receptors involved in antiviral response. BX795 is a pharmacological inhibitor of the TBK1/IKKɛ complex, which has been reported to augment lentiviral transduction of human NK cells and some cell lines, but it has not been tested with human primary T cells. The purpose of this study was to test if BX795 treatment promotes large payload RB-340-1 lentiviral transduction of human primary T cells. Methods To make the detection of gene delivery more convenient, we constructed another set of RB-340-1 constructs containing fluorescent labels named RB-340-1F. We incorporated BX795 treatment into the human primary T cell transduction procedure that was optimized for RB-340-1F. We tested BX795 with T cells collected from multiple donors, and detected the effect of BX795 on T cell transduction, phenotype, cell growth and cell function. Results We found that BX795 promotes RB-340-1F lentiviral transduction of human primary T cells, without dramatic change in cell growth and T cell functions. Meanwhile, BX795 treatment increased CD8+ T cell ratios in transduced T cells. Conclusions These results indicate that BX795 treatment is effective, and might be a safe approach to promote RB-340-1F lentiviral transduction of human primary T cells. This approach might also be helpful for other T cell therapy products that need delivery of complicated platform via large payload lentiviral vectors.