Abstract A171: Long-term episomal gene transfer for safe engineering of T cells for adoptive cell therapy of cancer

Abstract

Abstract Success in T-cell therapy of cancer is currently relying on long-term gene expression owing to retrovirus/lentivirus (RV/LV) integration. However, uncontrolled RV/LV integration in host cell genomes has the potential risk of causing insertional mutagenesis. Herein, we describe a novel episomal and long-term cell engineering method using non-integrating lentiviral (NILV) vector containing a scaffold matrix attachment region (S/MAR) element for either over-expression or down-regulation of genes. T-cells engineered with a NILV-S/MAR(CD19CAR) vector have similar levels of CAR expression as T-cells engineered with an integrating LV vector, even after numerous rounds of cell division. NILV-S/MAR-engineered CD19CAR-T-cells exhibited similar cytotoxic capacity upon CD19+ target cells recognition as LV-engineered T-cells. We propose that NILV-S/MAR vectors are superior to current options for enabling long-term gene expression without the risk of insertional mutagenesis. Citation Format: Chuan Jin, Mohanraj Ramachandran, Grammatiki Fotaki, Berith Nilsson, Magnus Essand, Di Yu. Long-term episomal gene transfer for safe engineering of T cells for adoptive cell therapy of cancer. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A171.