Zbtb46 coordinates tumor angiogenesis and tumor immunity to control tumor outcome
Tumor-angiogenesis and -immunity play critical roles in cancer progression and outcome. The existence of an inverse correlation hints at common regulatory mechanism(s) controlling these two processes. Here, we report that Zbtb46, a repressive transcription factor and widely accepted marker for classical dendritic cells (DCs), constitutes one such regulatory mechanism in the tumor microenvironment (TME) and is downregulated in both DCs and endothelial cells (ECs) by tumor-derived factors to facilitate robust tumor growth. This downregulation leads to the development of hallmark features of a pro-tumor environment, including dysfunctional vasculature and immunosuppressive cell accumulation. Analysis of cancer patient data revealed a similar association of a low ZBTB46 expression with an immunosuppressive TME and a worse prognosis. In contrast, upon enforced Zbtb46 expression, the hallmark TME features are mitigated, and tumor growth is restricted. Mechanistically, Zbtb46-deficient ECs were highly angiogenic, and Zbtb46-deficient bone-marrow precursors upregulated Cebpb and showed enhanced myeloid lineage output. Conversely, Zbtb46-maintenance normalizes ECs and, by suppressing Cebpb, skews the polarization of bone-marrow precursors towards more DCs and fewer macrophages, leading to an immune-hot TME. Remarkably, Zbtb46 mRNA treatment synergized with anti-PD1 immunotherapy to improve tumor management in pre-clinical models. These findings identify Zbtb46 as a common regulatory mechanism for angiogenesis and for non-hematopoietic-stem-cell-mediated myeloid lineage skewing in cancer and suggest that maintaining its expression could have therapeutic benefits. Overall design: Comparative gene expression profiling analysis of RNA-seq data for wild-type, Zbtb46 knockdown, and enforced Zbtb46 overexpression murine cardiac endothelial cells (MCEC).