PGE inhibits TIL expansion by disrupting IL-2 signalling and mitochondrial function.

Expansion of antigen-experienced CD8 T cells is critical for the success of tumour-infiltrating lymphocyte (TIL)-adoptive cell therapy (ACT) in patients with cancer. Interleukin-2 (IL-2) acts as a key regulator of CD8 cytotoxic T lymphocyte functions by promoting expansion and cytotoxic capability. Therefore, it is essential to comprehend mechanistic barriers to IL-2 sensing in the tumour microenvironment to implement strategies to reinvigorate IL-2 responsiveness and T cell antitumour responses.

PGE limits effector expansion of tumour-infiltrating stem-like CD8 T cells.

Cancer-specific TCF1 stem-like CD8 T cells can drive protective anticancer immunity through expansion and effector cell differentiation; however, this response is dysfunctional in tumours. Current cancer immunotherapies can promote anticancer responses through TCF1 stem-like CD8 T cells in some but not all patients. This variation points towards currently ill-defined mechanisms that limit TCF1CD8 T cell-mediated anticancer immunity.

Tumor-derived prostaglandin E2 programs cDC1 dysfunction to impair intratumoral orchestration of anti-cancer T cell responses.

Type 1 conventional dendritic cells (cDC1s) are critical for anti-cancer immunity. Protective anti-cancer immunity is thought to require cDC1s to sustain T cell responses within tumors, but it is poorly understood how this function is regulated and whether its subversion contributes to immune evasion. Here, we show that tumor-derived prostaglandin E2 (PGE) programmed a dysfunctional state in intratumoral cDC1s, disabling their ability to locally orchestrate anti-cancer CD8 T cell responses.