c-Met-targeted chimeric antigen receptor T cells inhibit hepatocellular carcinoma cells <i>in vitro</i> and <i>in vivo</i>
Xiaochen Huang, Jiaojiao Guo, Tao Li, Lizhou Jia, Xiaojun Tang, Jin Zhu, Qi Tang, Zhenqing Feng
Abstract
c-Met is a hepatocyte growth factor receptor overexpressed in many tumors such as hepatocellular carcinoma (HCC). Therefore, c-Met may serve as a promising target for HCC immunotherapy. Modifying T cells to express c-Met-specific chimeric antigen receptor (CAR) is an attractive strategy in treating c-Met-positive HCC. This study aimed to systematically evaluate the inhibitory effects of 2<sup>nd</sup>- and 3<sup>rd</sup>-generation c-Met CAR-T cells on hepatocellular carcinoma (HCC) cells. Here, 2<sup>nd</sup>- and 3<sup>rd</sup>-generation c-Met CARs containing an anti-c-Met single-chain variable fragment (scFv) as well as the CD28 signaling domain and CD3ζ (c-Met-28-3ζ), the CD137 signaling domain and CD3ζ (c-Met-137-3ζ), or the CD28 and CD137 signaling domains and CD3ζ (c-Met-28-137-3ζ) were constructed, and their abilities to target c-Met-positive HCC cells were evaluated <i>in vitro</i> and <i>in vivo</i>. All c-Met CARs were stably expressed on T cell membrane, and c-Met CAR-T cells aggregated around c-Met-positive HCC cells and specifically killed them <i>in vitro</i>. c-Met-28-137-3ζ CAR-T cells secreted more interferon-gamma (IFN-γ) and interleukin 2 (IL-2) than c-Met-28-3ζ CAR-T cells and c-Met-137-3ζ CAR-T cells. Compared with c-Met low-expressed cells, c-Met CAR-T cells secreted more cytokines when co-cultured with c-Met high-expressed cells. Moreover, c-Met-28-137-3ζ CAR-T cells eradicated HCC more effectively in xenograft tumor models compared with the control groups. This study suggests that 3<sup>rd</sup>-generation c-Met CAR-T cells are more effective in inhibiting c-Met-positive HCC cells than 2<sup>nd</sup>-generation c-Met CAR-T cells, thereby providing a promising therapeutic intervention for c-Met-positive HCC.