Redirecting T Cells to Glypican-3 with 4-1BB Zeta Chimeric Antigen Receptors Results in Th1 Polarization and Potent Antitumor Activity

Abstract

T cells engineered to express CD19-specific chimeric antigen receptors (CARs) have shown breakthrough clinical successes in patients with B-cell lymphoid malignancies. However, similar therapeutic efficacy of CAR T cells in solid tumors is yet to be achieved. In this study we systematically evaluated a series of CAR constructs targeting glypican-3 (GPC3), which is selectively expressed on several solid tumors. We compared GPC3-specific CARs that encoded CD3ζ (Gz) alone or with costimulatory domains derived from CD28 (G28z), 4-1BB (GBBz), or CD28 and 4-1BB (G28BBz). All GPC3-CARs rendered T cells highly cytotoxic to GPC3-positive hepatocellular carcinoma, hepatoblastoma, and malignant rhabdoid tumor cell lines in vitro. GBBz induced the preferential production of Th1 cytokines (interferon γ/granulocyte macrophage colony-stimulating factor) while G28z preferentially induced Th2 cytokines (interleukin-4/interleukin-10). Inclusion of 4-1BB in G28BBz could only partially ameliorate the Th2-polarizing effect of CD28. 4-1BB induced superior expansion of CAR T cells in vitro and in vivo. T cells expressing GPC3-CARs incorporating CD28, 4-1BB, or both induced sustained tumor regressions in two xenogeneic tumor models. Thus, GBBz CAR endows T cells with superior proliferative potential, potent antitumor activity, and a Th1-biased cytokine profile, justifying further clinical development of GBBz CAR for immunotherapy of GPC3-positive solid tumors.

Anti-GPC3-CAR T Cells Suppress the Growth of Tumor Cells in Patient-Derived Xenografts of Hepatocellular Carcinoma

“…Previous studies have shown that GPC3-CAR T cells efficiently eradicate liver cancer cells lines that possess a high level of GPC3 expression in vivo (13, 14). Here, we observed that GPC3-CAR T cells were less effective to kill HCC cell lines in xenografts, compared to a previous report (13).…”

“…GPC3 is, therefore, a suitable target for CAR T cell therapy. Two previous studies showed the promising activity of GPC3-CAR T cells against HCC cell lines in vivo (13, 14). However, the capacity of GPC3-CAR T cells to eliminate HCC has not been evaluated in PDX models yet.…”

T Cell–Associated Immunotherapy for Hepatocellular Carcinoma

“…Recently, several studies selected GPC3 as a HCC TAA [69,84,85]. Gao H, et al and Li W, et al constructed CAR-T cells that could specifically target GPC3 on the surface of HCC cells, as the attempts to apply CAR-T cell immunotherapy for the treatment in HCC, which showed significant anti-tumor activity both in vitro and in vivo [84,85]. CAR-T cells specific for HBV envelope proteins localized to liver in mice which reduced HBV replication with transient liver damage [86].…”

Immunotherapy of hepatocellular carcinoma using chimeric antigen receptors and bispecific antibodies

“…It has been shown that GPC3 is expressed on the majority of hepatocellular carcinoma (HCC) and hepatoblatsoma cases but not or to a lower degree on normal liver tissue [51, 57, 67, 84]. Interestingly, GPC3 expression could be used as an HCC precancerous marker in cirrhotic livers since it is associated with dysplasia in cirrhotic livers [74].…”