Immune Checkpoint Blockade via PD-L1 Potentiates More CD28-Based than 4-1BB-Based Anti-Carbonic Anhydrase IX Chimeric Antigen Receptor T Cells

Abstract

The complete regression of clear cell renal cell carcinoma (ccRCC) obtained pre-clinically with anti-carbonic anhydrase IX (CAIX) G36 chimeric antigen receptor (CAR) T cells in doses equivalent to ≅108 CAR T cells/kg renewed the potential of this target to treat ccRCC and other tumors in hypoxia. The immune checkpoint blockade (ICB) brought durable clinical responses in advanced ccRCC and other tumors. Here, we tested CD8α/4-1BB compared to CD28-based anti-CAIX CAR peripheral blood mononuclear cells (PBMCs) releasing anti-programmed cell death ligand-1 (PD-L1) IgG4 for human ccRCC treatment in vitro and in an orthotopic NSG mice model in vivo. Using a ≅107 CAR PBMCs cells/kg dose, anti-CAIX CD28 CAR T cells releasing anti-PD-L1 IgG highly decrease both tumor volume and weight in vivo, avoiding the occurrence of metastasis. This antitumoral superiority of CD28-based CAR PBMCs cells compared to 4-1BB occurred under ICB via PD-L1. Furthermore, the T cell exhaustion status in peripheral CD4 T cells, additionally to CD8, was critical for CAR T cells efficiency. The lack of hepatotoxicity and nephrotoxicity upon the administration of a 107 CAR PMBCs cells/kg dose is the basis for carrying out clinical trials using anti-CAIX CD28 CAR PBMCs cells releasing anti-PD-L1 antibodies or anti-CAIX 4-1BB CAR T cells, offering exciting new prospects for the treatment of refractory ccRCC and hypoxic tumors.

4-1BB-Based CAR T Cells Effectively Reverse Exhaustion and Enhance the Anti-Tumor Immune Response through Autocrine PD-L1 scFv Antibody

“…To enhance the antitumor activity of CAR T cells against CD19 positive B-ALL and Her2 positive breast cancers, we inserted CD19.BBz, CD19.BBz.PD-L1, Her2.BBz, and Her2.BBz.PD-L1 CARs into the multi-cloning site of pCDH-EF1α-MCS-CMV-copGFP vector ( Figure 1 A). We chose the 4-1BB signaling fragment due to its greater persistence of CAR T cells in vivo [ 7 , 20 ]. The IRES (internal ribosome entry site) allows the translation of scFv PD-L1 antibody.…”

“…A large body of research has revealed that the exhaustion of CAR T cells can be reversed by blocking the PD-1/PD-L1 signaling pathway [ 7 , 8 ]. A combination of CAR T cells with immune checkpoint blocking (ICB) drugs has been used in the treatment of multiple tumors with much improved efficacy [ 9 , 10 ].…”

“…A combination of CAR T cells with immune checkpoint blocking (ICB) drugs has been used in the treatment of multiple tumors with much improved efficacy [ 9 , 10 ]. In particular, PD-1/PDL1 antibodies applied in combination with CAR T cells are potent to overcome the immunosuppression of TME [ 7 , 8 ]. In a glioma mouse model, PD-1 antibody injection enhanced the anti-tumor effect of CAR T cells and protected CAR T cells from exhaustion and cell death induced by prolonged antigen stimulation [ 11 ].…”

“…Most studies on the reversal of T cell exhaustion by PD-1/PD-L1 blockade focused on CD28-based CAR T cells. 4-1BB-based CAR T cells showed more persistence in vivo compared with CD28-based CAR T [ 7 ]. However, whether 4-1BB-based CAR T cells could benefit from self-secreted PD-L1 scFv antibody to reverses T cell exhaustion has not been investigated.…”

Progress of Section “Biochemistry” in 2022

“…A relevant number of papers dealing with this enzyme, its inhibitors, activators and involvement in various diseases have been published in 2022 in this journal [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. The first group of contributed materials dealt with the use of this protein for investigations of basic biochemical approaches, such as protein folding [ 7 ], thermodynamic parameters assessment for protein–ligand interactions [ 8 ], bioluminescence resonance energy transfer connected to the binding of the metal ion to apoenzymes [ 9 ], the possibility to evidence chalcogen bonds in the X-ray crystal structures of CA–lig and adduct [ 10 ].…”