FIGURE 5.

RIME inhibition enhanced antitumour immunity in oesophageal squamous cell carcinoma (ESCC) treatment. (A, B) Graphic illustration of the construction of Hu‐PBMC‐NOG and time points of administration and sampling. (C) Xenografts from the Hu‐PBMC‐NOG mouse model were collected and photographed on day 30. RIME CRISPR KO dramatically repressed tumour growth and improved the anti‐tumour efficacy of PD‐1mAb. (D) ScRNA‐seq data of xenografts from the Hu‐PBMC‐NOG mouse model was aligned and quantified using the CellRanger toolkit v.3.1. Major cell types in the tumour tissue were clustered using Seurat (v.3.2.3). ScRNA‐seq analysis of the xenografts suggested that RIME KO increased CD8⁺ T cells and cytotoxic CD8⁺ T cells. (E) Flow cytometry analysis showed that RIME KO increased the proportion of CD8⁺ T cells and IFN‐γ⁺ CD8⁺ T cells in the ESCC xenografts. (F) Representative flow cytometry results showed that RIME KO increased the proportion of IFN‐γ⁺ CD8⁺ T cells in the ESCC xenografts. (G‐H) Multiplex fluorescent immunohistochemistry assays showed that RIME KO increased the proportion of CD8⁺ T cells and GranB⁺ CD8⁺ T cells in the ESCC xenografts. Scale bar, 50 μm. (I) As indicated, Hu‐PBMC‐NOG‐PDX mice were injected with Ctrl or RIME inhibitor (10 nmol per injection) with or without PD‐1 mAb (200 μg per injection). It showed that targeting RIME significantly inhibited tumour development. The RIME inhibitor increased the proportion of CD8⁺ T cells and IFN‐γ⁺ CD8⁺ T cells in the ESCC patient‐derived xenografts.