The heterogeneous nature of tumor-associated neutrophils (TANs) has been recognized, but how different cell states of TANs emerge, evolve, distribute, and impact cancer immunotherapy efficacy remain e Show more
The heterogeneous nature of tumor-associated neutrophils (TANs) has been recognized, but how different cell states of TANs emerge, evolve, distribute, and impact cancer immunotherapy efficacy remain elusive. Using single-cell RNA sequencing, spatial transcriptomics, and genetic manipulations, we show that anti-PDL1 + CD40 agonist immunotherapy can induce interferon responses in TANs, allowing them to regain anti-tumor activities in squamous cell carcinomas (SCCs). In contrast, TANs residing at the tumor-stroma interface can preserve their immune-suppressive state. Importantly, we identify a group of SOX2 Show less
Tumors depend upon angiogenesis for growth and metastasis. It is therefore critical to understand the inhibitory signaling mechanisms in endothelial cells that control angiogenesis. Epac is a cyclic a Show more
Tumors depend upon angiogenesis for growth and metastasis. It is therefore critical to understand the inhibitory signaling mechanisms in endothelial cells that control angiogenesis. Epac is a cyclic adenosine 5'-monophosphate-activated guanine nucleotide exchange factor for Rap1. In this study, we show that activation of Epac or Rap1 leads to potent inhibition of angiogenesis in vivo. Epac/Rap1 activation down-regulates inhibitor of differentiation 1 (Id1), which negatively regulates thrombospondin-1 (TSP1), an inhibitor of angiogenesis. Consistent with this mechanism, activation of Epac/Rap 1 induces expression of TSP1; conversely, depletion of Epac reduces TSP1 levels in endothelial cells. Blockade of TSP1 binding to its receptor, CD36, rescues inhibition of chemotaxis or angiogenesis by activated Epac/Rap1. Mitogen-activated protein kinase kinase 5, a downstream mediator of vascular endothelial growth factor, antagonizes the effects of Epac/Rap1 by inducing Id1 and suppressing TSP1 expression. Finally, TSP1 is also secreted by fibroblasts in response to Epac/Rap1 activation. These results identify Epac and Rap1 as inhibitory regulators of the angiogenic process, implicate Id1 and TSP1 as downstream mediators of Epac/Rap1, and highlight a novel interplay between pro- and antiangiogenic signaling cascades involving multiple cell types within the angiogenic microenvironment. Show less