Rational design of TGFbRII dominant negative armored GPC3 CAR-T cells for the treatment of hepatocellular carcinoma

Abstract Chimeric antigen receptor (CAR)-T therapy has yielded impressive clinical results in hematological malignancies and it is a promising approach for solid tumor treatment. However, toxicity concern hampering its broader use. In selecting lead CAR-T candidate against the oncofetal glypican 3 (GPC3), we employed strategy to manage profile by single-chain variable fragment with reduced affinity characterized high dissociation rate. Compared high-affinity construct, low-affinity CAR maintained cytotoxic function but showed mouse model of hepatocellular carcinoma (HCC). The HCC microenvironment rich immunosuppressive cytokine TGFβ, prompting us armor low GPC3 cells dominant-negative TGFβRII (TGFβRIIDN). vitro, expression TGFβRIIDN nearly abolished TGFβ-induced SMAD2/3 phosphorylation suppression IL-2 IFNg production. xenograft human TGFβ highHCC, armored had 10/10 complete responders (CR) while unarmored 4/10 CRs. four highpatient-derived models achieved 60–90% growth inhibition (TGI) no significant TGI. infiltrated highHCC tumors more abundantly than their counterparts expressed lower levels immune checkpoint markers PD1 LAG3. line these observations, detected significantly at peak response, confirming vivo functional superiority therapy. These data support development AZD5851, TGFβRIIDN.