Abstract
Small cell lung cancer (SCLC) is exceptionally aggressive, with limited treatment options. Disialoganglioside (GD2) is highly expressed on SCLC and is considered a good target for chimeric antigen receptor (CAR) T cells (CART). Although GD2-directed CARTs (GD2-CART) exhibit cytotoxicity against various GD2-expressing tumors, they lack significant cytotoxicity against SCLC. To enhance cytotoxicity of GD2-CARTs against SCLC, we introduced GD2-CAR into induced pluripotent stem cells (iPSC)-derived rejuvenated cytotoxic T lymphocytes (GD2-CARrejT). GD2-CARrejTs acted much more strongly against SCLC cells than did GD2-CARTs both in vitro and in vivo. Single-cell RNA sequencing elucidated that levels of expression of TIGIT were significantly lower and levels of expression of genes associated with cytotoxicity were significantly higher in GD2-CARrejTs than those in GD2-CARTs. Dual blockade of TIGIT and programmed death-1 (PD-1) increased the cytotoxicity of GD2-CARTs to some extent, suggesting that low TIGIT and PD-1 expression by GD2-CARrejTs is a major factor required for robust cytotoxicity against SCLC. Not only for robust cytotoxicity but also for availability as "off-the-shelf" T-cell therapy, iPSC-derived GD2-CARrejTs are a promising novel treatment for SCLC. Significance: This research introduces iPSC-derived rejuvenated GD2-CARTs (GD2-CARrejT) as a novel approach to combat SCLC. Compared with conventional GD2-CARTs, GD2-CARrejTs with reduced TIGIT and PD-1 expression demonstrate robust cytotoxicity against SCLC and would be a promising therapy for SCLC.