Treatment of hepatocellular carcinoma with a GPC3-targeted bispecific T cell engager

There are limited strategies for the treatment of hepatocellular carcinoma (HCC). In this study, we prepared a Bispecific T cell engager (BiTE) targeting Glypican 3 (GPC3) and CD3. The GPC3/CD3 BiTE was prepared by fusing the single-chain variable fragment (scFv) of the humanized anti-GPC3 antibody (9F2) with the scFv of the anti-CD3 antibody (OKT3). The in vitro and in vivo cytotoxic activities of the GPC3/CD3 BiTE were evaluated against various HCC cell lines. The GPC3/CD3 BiTE could efficiently mediate the T cell killing of GPC3-positive HCC in vitro, which was dependent on GPC3 expression on the surface of HCC cells. Moreover, our study indicates that, in the presence of the GPC3/CD3 BiTE, T cells could efficiently destroy GPC3-positive human HCC cells in vitro and in vivo. Additionally, our study further proved that GPC3 is not expressed in normal tissues. Thus, GPC3 may be a cancer-specific antigen. Collectively, these findings suggest that this anti-GPC3 BiTE might be a promising anti-tumor reagent for patients with GPC3-positive HCC.