PD-1-targeted immunotherapy in NASH-triggered liver cancer induces pro-tumorigenic environment through CD8+PD-1+ T-cells

Whereas some cancer types (e.g. melanoma) can be efficiently treated with immunotherapy, others lack measurable positive effects (e.g. PDAC ). Moreover, stratification of responders/non-responders is only possible in some cancer types (e.g. melanoma). Hepatocellular carcinoma (HCC) has a dismal prognosis, limited treatment options and survival benefit, and represents a potential cancer entity for successful immunotherapy. Here, we investigated NASH -triggered HCC in the context PD-1-targeted immunotherapy. Using flow cytometry, single cell RNA sequencing, immunohistochemistry and mass spectrometric analyses, we found a progressive increase of CD8+PD-1+ effector T-cells with a unique profile of exhaustion and activation markers rising with murine and human NASH severity. Notably, late-stage HCC treatment with PD-1-targeted immunotherapy enhanced hepatic carcinogenesis in mice. To dissect potential mechanisms of action during tumor-initiation and -progression we analyzed the effects of PD-1-targeted immunotherapy at HCC initiation. Anti-PD-1 treatment induced a pro-tumorigenic environment, enhanced necro-inflammation and increased NAFLD -activation score (NAS), leading to increased liver cancer incidence, tumor number and nodule size. In contrast, anti-CD8 treatment reduced NAS and abrogated the development of liver cancer, thus identifying CD8+PD-1+ T-cells as drivers of liver cancer in NASH-triggered HCC. Increased apoptotic signaling, STAT3 phosphorylation and hepatic proliferation were detected in intra-tumoral liver tissue upon PD-1-targeted immunotherapy. In line, PD-1-/- mice challenged with a NASH diet displayed early onset of hepatocarcinogenesis, corroborating the pro-tumorigenic role of absent or reduced PD-1. Mechanistically PD-1-targeted immunotherapy increased hepatic abundance of CD8+PD-1+Tox+CXCR6+CD8+PD-1+TNF+CD39+Gzmb+ T cells found in NASH livers, creating a pro-tumorigenic liver environment . Overall design: Hepatic CD4+ or CD8+ T-cells of 12 months NASH-diet + 8 weeks treatment (IgG, a-PD-1 or a-CD8) mice were isolated by liver perfusion, mechanical + enzymatic digestion and percoll gradient enrichment and subsequently single-cell sorted (sorted gate: L/D-,CD11b-,CD11c-,CD19-,CD45+,CD4+ or CD8+ cells) and frozen on dry-ice .?