ATAC-seq of PBMC from dog bearing mammary gland tumor

Circulating immune cells that have interacted with tumor tissue exhibit distinct characteristics compared to those in healthy individuals, potentially offering critical insights into tumor presence and malignancy. However, the epigenetic mechanisms governing these blood immune cells in cancer patients remain poorly understood. In this study, we investigated chromatin accessibility and transcription factor binding in peripheral blood mononuclear cells (PBMCs) from dogs with mammary gland tumors using ATAC-seq. Our analysis revealed altered chromatin accessibility near genes associated with immune function, neuronal activity, and lipid metabolism in affected dogs. Notably, we identified CEBPD-bound peaks that were upregulated in cancer-affected PBMCs and demonstrated that the transcription of their associated genes, CD47 and MAP4K4, was also upregulated in monocytes under cancer co-culture conditions—an effect that was mitigated following CRISPR interference of these regions. These findings underscore the critical role of chromatin accessibility and transcriptional regulation in the immune response to cancer Overall design: 42 ATAC-seq generated from 6 normal dogs, 6 dogs with benign mammary gland tumor, and 9 dogs with maliganant mammary gland tumor