Nishimura Yasuharu, Nakatsura Tetsuya, Senju Satoru
Department of Immunogenetics, Kumamoto University Graduate School of Medical Sciences.
Nihon Rinsho Meneki Gakkai Kaishi. 2008 Oct;31(5):383-91. doi: 10.2177/jsci.31.383.
We identified glypican-3 (GPC3), as a novel oncofetal antigen, overexpressed specifically in hepatocellular carcinoma (HCC) and melanoma in humans by utilizing genome-wide cDNA microarray analyses of HCC tissues and normal fetal and adult tissues. We also found that GPC3 is a novel tumor marker for HCC and melanoma, and that the pre-immunization 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 binding peptide motifs between H-2K(d) and HLA-A24 (A()2402), the H-2K(d)-restricted GPC3 298-306 peptide thus seemed to be useful for the immunotherapy of HLA-A24(+) patients with HCC and melanoma. We investigated whether the GPC3 298-306 peptide could induce GPC3 reactive CTLs from the peripheral blood mononuclear cells (PBMCs) of HLA-A24 (A()2402)(+) HCC patients. In addition, we used HLA-A2.1 (HHD) transgenic mice (Tgm) to identify the HLA-A2 (A(*)0201)-restricted GPC3 epitopes to expand the applications of GPC3 based immunotherapy to the HLA-A2(+) HCC patients. We found that the GPC3 144-152 (FVGEFFTDV) peptide could induce peptide-reactive CTLs in HLA-A2.1 (HHD) Tgm without inducing autoimmunity. In 5 out of 8 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 4 of 6 HLA-A24(+) GPC3(+) HCC patients. The inoculation of these CTLs reduced the human HCC tumor mass implanted into NOD/SCID mice. We have recently started a phase I clinical trial of GPC3 peptide vaccine-based immunotherapy of patients with advanced HCC. We have also succeeded in inhibition of growth of tumors expressing mouse GPC3 by immunization of mice with dendritic cells differentiated in vitro from mouse embryonic stem cells and pulsed with the GPC3 peptides. Our study raises the possibility that these GPC3 peptides may therefore be applicable to cancer immunotherapy for a large number of patients with HCC and melanoma.
我们通过对肝癌组织以及正常胎儿和成人组织进行全基因组cDNA微阵列分析，确定了磷脂酰肌醇蛋白聚糖-3（GPC3）作为一种新的癌胚抗原，在人类肝癌（HCC）和黑色素瘤中特异性过表达。我们还发现GPC3是肝癌和黑色素瘤的一种新型肿瘤标志物，用H-2K(d)限制性小鼠GPC3 298-306（EYILSLEEL）肽脉冲处理的树突状细胞对BALB/c小鼠进行预免疫，可抑制表达小鼠GPC3的肿瘤生长。由于H-2K(d)和HLA-A24（A()2402）之间的结合肽基序存在相似性，因此H-2K(d)限制性GPC3 298-306肽似乎可用于HLA-A24(+)肝癌和黑色素瘤患者的免疫治疗。我们研究了GPC3 298-306肽是否能从HLA-A24（A()2402)(+)肝癌患者的外周血单个核细胞（PBMC）中诱导出GPC3反应性CTL。此外，我们使用HLA-A2.1（HHD）转基因小鼠（Tgm）来鉴定HLA-A2（A(*)0201）限制性GPC3表位，以将基于GPC3的免疫治疗应用扩展到HLA-A2(+)肝癌患者。我们发现GPC3 144-152（FVGEFFTDV）肽可在HLA-A2.1（HHD）Tgm中诱导肽反应性CTL，且不诱导自身免疫。在8例HLA-A2(+) GPC3(+)肝癌患者中的5例中，通过用该肽体外刺激PBMC产生了GPC3 144-152肽反应性CTL，在6例HLA-A24(+) GPC3(+)肝癌患者中的4例中，PBMC也产生了GPC3 298-306肽反应性CTL。接种这些CTL可减少植入NOD/SCID小鼠体内的人肝癌肿瘤块。我们最近启动了一项针对晚期肝癌患者的基于GPC3肽疫苗免疫治疗的I期临床试验。我们还通过用从小鼠胚胎干细胞体外分化并经GPC3肽脉冲处理的树突状细胞免疫小鼠，成功抑制了表达小鼠GPC3的肿瘤生长。我们的研究提出了这些GPC3肽可能因此适用于大量肝癌和黑色素瘤患者的癌症免疫治疗的可能性。
