Neoantigen vaccination augments antitumor effects of anti-PD-1 on mouse hepatocellular carcinoma
Journal
Cancer letters
Journal Volume
563
Date Issued
2023-04-22
Author(s)
Yang, Shih-Feng
Chiou, Ling-Ling
Hsu, Yu-Chen
Lee, Ying-Te
Liu, Shin-Yun
Wu, Meng-Chuan
Chou, Huei-Chi
Wang, Li-Fang
Sheu, Jin-Chuan
Abstract
Immune checkpoint inhibitors are groundbreaking resources for cancer therapy. However, only a few patients with hepatocellular carcinoma (HCC) have shown positive responses to anti-PD-1 therapy. Neoantigens are sequence-altered proteins resulting from somatic mutations in cancer. This study identified the neoantigens of Hep-55.1C and Dt81 Hepa1-6 HCCs by comparing their whole exome sequences with those of a normal C57BL/6 mouse liver. Immunogenic long peptides were pooled as peptide vaccines. The vaccination elicited tumor-reactive immune responses in C57BL/6 mice, as demonstrated by IFN-γ ELISPOT and an in vitro killing assay of splenocytes. In the treatment of three mouse HCC models, combined neoantigen vaccination and anti-PD-1 resulted in more significant tumor regression than monotherapies. Flow cytometry of the tumor-infiltrating lymphocytes showed decreased Treg cells and monocytic myeloid-derived suppressor cells, increased CD8+ T cells, enhanced granzyme B expression, and reduced exhaustion-related markers PD-1 and Lag-3 on CD8+ T cells in the combination group. These findings provide a strong rationale for conducting clinical studies of using neoantigen vaccination in combination with anti-PD-1 to treat patients with HCC.
Subjects
Cancer vaccine; Combination immunotherapy; Long peptide; Next generation sequencing; Poly-ICLC
SDGs
Type
journal article