Integrative single cell and spatial transcriptomics of colorectal cancer reveals multicellular functional units that support tumor progression

Abstract

Abstract While advances in single cell genomics have helped to chart the cellular components of tumor ecosystems, it has been more challenging to characterize their specific spatial organization and functional interactions. Here, we combine single cell RNA-seq and spatial transcriptomics by Slide-seq, to create a detailed spatial map of healthy and dysplastic colon cellular ecosystems and their association with disease progression. We profiled an inducible genetic CRC mouse model that recapitulates key features of human CRC, assigned cell types and epithelial expression programs to spatial tissue locations in tumors, and computationally used them to identify the regional features spanning different cells in the same spatial niche. We find that tumors were organized in cellular neighborhoods, each with a distinct composition of cell subtypes, expression programs, and local cellular interactions. Three cellular neighborhood archetypes were associated with tumor progression, were active at the same time in different spatial parts of the same tumor, involved dysplasia-specific cellular layouts, and relied on distinct mechanisms: ( 1 ) inflammatory epithelial regions with endothelial cells and monocytes expressing angiogenesis, inflammation and invasion programs; ( 2 ) epithelial stem-like regions, associated with plasma and B cell activity; and ( 3 ) epithelial-to-mesenchymal transition (EMT) regions with dysplastic cells expressing a Wnt signaling program. Comparing to scRNA-seq and Slide-seq data from human CRC, we find that both cell composition and layout features were conserved in both species, with mouse archetypal neighborhoods correlated with malignancy and clinical outcome in human patient tumors, highlighting the relevance of our findings to human disease.