Identification of HLA-A2- or HLA-A24-Restricted CTL Epitopes Possibly Useful for Glypican-3-Specific Immunotherapy of Hepatocellular Carcinoma

Abstract

Purpose and Experimental Design: We previously reported that glypican-3 (GPC3) was overexpressed, specifically in hepatocellular carcinoma (HCC) and melanoma in humans, and it was useful as a novel tumor marker. We also reported that the preimmunization of BALB/c mice with dendritic cells pulsed with the H-2K d -restricted mouse GPC3 298-306 (EYILSLEEL) peptide prevented the growth of tumor-expressing mouse GPC3. Because of similarities in the peptide binding motifs between H-2K d and HLA-A24 (A*2402), the GPC3 298-306 peptide therefore seemed to be useful for the immunotherapy of HLA-A24 + patients with HCC and melanoma. In this report, we investigated whether the GPC3 298-306 peptide could induce GPC3-reactive CTLs from the peripheral blood mononuclear cells (PBMC) of HLA-A24 (A*2402) + HCC patients. In addition, we used HLA-A2.1 (HHD) transgenic mice to identify the HLA-A2 (A*0201)^restricted GPC3 epitopes to expand the applications of GPC3-based immunotherapy to the HLA-A2 + HCC patients. Results: We found that the GPC3 144-152 (FVGEFFTDV) peptide could induce peptide-reactive CTLs in HLA-A2.1 (HHD) transgenic mice without inducing autoimmunity. In five out of eight HLA-A2 + GPC3 + HCC patients, the GPC3 144-152 peptide-reactive CTLs were generated from PBMCs by in vitro stimulation with the peptide and the GPC3 298-306 peptide-reactive CTLs were also generated from PBMCs in four of six HLA-A24 + GPC3 + HCC patients. The inoculation of these CTLs reduced the human HCC tumor mass implanted into nonobese diabetic/ severe combined immunodeficiency mice. Conclusion: Our study raises the possibility that these GPC3 peptides may therefore be applicable to cancer immunotherapy for a large number of HCC patients.

Detection of glypican-3-specific CTLs in chronic hepatitis and liver cirrhosis

“…We recently identified GPC3-specific peptides restricted to HLA-A24 (A * 2402) and H-2K d , or HLA-A2 (A * 0201), both of which can induce GPC3-reactive cytotoxic T cells (CTLs) (19). We are currently conducting a phase I clinical trial of peptide vaccine prepared using these peptides against advanced HCC.…”

“…SK-Hep-1/GPC3 has been described previously (19). HepG2 endogenously expressing GPC3 was kindly provided by the Cell Resource Center for Biomedical Research Institute of Development, Aging, and Cancer (Tohoku University, Sendai, Japan).…”

“…We recently identified both HLA-A24 (A * 2402) and H-2K d -restricted GPC3 298-306 (EYILSLEEL) and HLA-A2 (A * 0201)-restricted GPC3 144-152 (FVGEFFTDV), both of which can induce GPC3-reactive cytotoxic T cells (CTLs) (19). We previously reported a preclinical study conducted in a mouse model with a view to designing an optimal schedule for clinical trials of a GPC3-derived peptide vaccine (20).…”

Glypican-3 is a useful diagnostic marker for a component of hepatocellular carcinoma in human liver cancer

“…We developed a new anti-cancer immunotherapy with GPC3 as a target (44)(45)(46)(47), and the phase I clinical trial of GPC3-derived peptide vaccination for advanced HCC is now on going. Because this new immunotherapy is not indicated for ICC, immunohistochemical staining of GPC3 is a useful method to select eligible patients.…”

Immunotherapy and Hepatocellular Carcinoma

“…T-cell responses was elicited after in-vitro peptide stimulation in about half of HCC patients with an HLA-A2 or HLA-A24 allele [9]. CD8+ T-cells specific for NY-ESO-1, a cancer testis antigen expressed by HCC, have been found in HCC patients, but notably the cells have impaired cytolytic function [8,9]. Responses to several other cancer testis antigens also expressed de novo in HCC and first described in melanoma, such as SSX-2 and MAGE, have been reported with in-vitro stimulation in HCC cell lines [10,11].…”