A Cytotoxic T Cell Inspired Oncolytic Nanosystem Promotes Lytic Cell Death by Lipid Peroxidation And Elicits Antitumor Immune Responses

Lytic cell death, such as pyroptosis, can trigger antitumour immune response. However, cancerous cells avoid lytic cell death by various escape mechanisms acquired through evolution. Moreover, persistent uncontrolled lytic cell death may inversely cause hyperactive immune response or T-cell exhaustion. Therefore, an oncolytic system capable of breaking through natural restrictions to dissolve cancer cells in a catalytic and controllable manner is needed. Here, we established a microscale cytotoxic T-cell-inspired oncolytic system (TIOs) by which the NIR light-generated reactive oxygen species could precisely rupture the plasma membrane of cancer cells by direct lipids peroxidation. Similar as cytotoxic T cells, TIOs present antigen-based cell recognition and catalytic cell-lysis ability; thus, the TIOs can trigger significant oncolysis and immune response in vivo. The TIOs exhibited exceptional tumour targeting and penetration without any inflammatory risk. We applied TIOs to antitumour therapies, which showed kinds of tumour models could be cleared efficiently with negligible injuries to major organs. Tumour regression was correlated with oncolysis-mediated inflammation and T-cell-based antitumor immune response. Owing to the tuneability of TIOs-mediated oncolysis, we further revealed that though the T-cell recruitment was comparable, the high-intense oncolysis induced acute inflammation in initial stage was crucial for potent antitumour immunity and immune memory effects, and low-intense oncolysis resulted in T-cell exhaustion and tumour progression. To the mice received low-intense oncolysis, although synergizing with anti-PD-1 therapies or STING activation rescued the immune dysfunction, STING activation released a more powerful boost to durative antitumour immunity by reshaping the stemness of CD8+ T cells. Our study provides new insights to design the oncolytic systems for antitumour immunity. Moreover, our application suggests that the intensity of initial inflammation plays a decisive role in maintaining oncolysis-induced antitumour immune function and STING activation holds promise for reversal of immune dysfunction due to T-cell exhaustion. FACS analysis of tumour-infiltrating lymphocytes and tumour-infiltrating lymphocytes isolated in tumour models was performed after staining with a PE-conjugated anti- mouse CD45 antibody (clone 30-F11, Biolegend). CD45+ immune cells were then enriched using a BD FACS Aria III flow cytometer. Cell viability was monitored in real time during the preparation of single CD45+ immune cell suspensions. Ten thousand cells (~600 single cells per microlitre) from each experimental group were barcoded and pooled using a 10x Genomics device. Samples were prepared according to the manufacturer's protocol and sequenced on an Illumina NextSeq sequencer. The Cell Ranger Analysis Pipeline (v.3.0.2) was used for sample demultiplexing, barcode processing, alignment, filtering, UMI counting, and aggregation of sequencing runs. For quality control of the single-cell RNA-sequencing process, cells with fewer than 300 genes detected and cells with mitochondrial-encoding gene transcript counts exceeding 15% of total transcript counts were removed from subsequent analyses. Genes detected in less than three cells in the entire dataset were also excluded, resulting in a preliminary expression matrix of 15603 cells. After obtaining the digital gene expression data matrix, dimensionality reduction, clustering and differential gene expression analysis were performed using Seurat (v.3.0.0.9000)