Engineered triple inhibitory receptor resistance improves anti-tumor CAR-T cell performance via CD56

Fan Zou,Jun Liu,Lijuan Lu,Mei Huang,Qifei Hu,Shuliang Jing,Yingtong Lin,Bifen Huang,Wanying Zhang,Yiwen Zhang,Bingfeng Liu,Hui Zhang,Baijin Xia,Weiwei Liu

doi:10.1038/s41467-019-11893-4

Abstract

The inhibitory receptors PD-1, Tim-3, and Lag-3 are highly expressed on tumor-infiltrating lymphocytes and compromise their antitumor activity. For efficient cancer immunotherapy, it is important to prevent chimeric antigen receptor T (CAR-T)-cell exhaustion. Here we downregulate these three checkpoint receptors simultaneously on CAR-T cells and that show the resulting PTL-CAR-T cells undergo epigenetic modifications and better control tumor growth. Furthermore, we unexpectedly find increased tumor infiltration by PTL-CAR-T cells and their clustering between the living and necrotic tumor tissue. Mechanistically, PTL-CAR-T cells upregulate CD56 (NCAM), which is essential for their effector function. The homophilic interaction between intercellular CD56 molecules correlates with enhanced infiltration of CAR-T cells, increased secretion of interferon-γ, and the prolonged survival of CAR-T cells. Ectopically expressed CD56 promotes CAR-T cell survival and antitumor response. Our findings demonstrate that genetic blockade of three checkpoint inhibitory receptors and the resulting high expression of CD56 on CAR-T cells enhances the inhibition of tumor growth.

Highlights

The inhibitory receptors PD-1, Tim-3, and Lag-3 are highly expressed on tumor-infiltrating lymphocytes and compromise their antitumor activity
It has been shown that PD-1, Tim-3, and Lag-3 are highly expressed on tumor-infiltrating lymphocytes (TILs) in various solid tumor types[4,28,29,30,31], as well as on CD8+ T cells during chronic viral infections[32,33]
After confirming that the Her2-specific chimeric antigen receptor T (CAR-T) cells with the downregulation of each inhibitory receptor exerted higher Her2-specific cytotoxicity (Supplementary Fig. 2c, d), we generated the Her2-specific CART cells carrying short hairpin RNA (shRNA) cluster for three co-inhibitory molecules, which was thereafter named as PTL-Her2-CAR-T cells

Summary

Introduction

The inhibitory receptors PD-1, Tim-3, and Lag-3 are highly expressed on tumor-infiltrating lymphocytes and compromise their antitumor activity. Our findings demonstrate that genetic blockade of three checkpoint inhibitory receptors and the resulting high expression of CD56 on CAR-T cells enhances the inhibition of tumor growth. Chimeric antigen receptor T cells (CAR-T cells) have exerted potent antitumor activity They effectively eradicate the leukemic/lymphoma cells and lead to an impressive clinic success, their inhibitory effect on solid tumors is compromised[18]. More efforts have been made to improve the anti-solid tumor activity, including coexpression of IL-7 and CCL19, heparanase, IL-12, or CCR2b in the CAR-T cells[23,24,25,26,27] Their enhancement for antitumor activity in patients remains to be determined. Further studies demonstrate that the CD56 molecule is upregulated on these PTL-Her2-CAR-T cells and the homophilic interaction between intercellular CD56 molecules potently enhances the anti-solid tumor activity and prolonged survival

Methods

Results

Conclusion