Here, using single-cell RNA sequencing, we examine the stromal compartment in murine melanoma and draining lymph nodes (LNs) at points across tumor development, providing data at http://www.teichlab.org/data/.,Naive lymphocytes from LNs undergo activation and clonal expansion within the tumor, before PD1 and Lag3 expression, while tumor-associated myeloid cells promote the formation of a suppressive niche.,We identify three temporally distinct stromal populations displaying unique functional signatures, conserved across mouse and human tumors.,Whereas “immune” stromal cells are observed in early tumors, “contractile” cells become more prevalent at later time points.,Complement component C3 is specifically expressed in the immune population.,Its cleavage product C3a supports the recruitment of C3aR+ macrophages, and perturbation of C3a and C3aR disrupts immune infiltration, slowing tumor growth.,Our results highlight the power of scRNA-seq to identify complex interplays and increase stromal diversity as a tumor develops, revealing that stromal cells acquire the capacity to modulate immune landscapes from early disease.,•scRNA-seq reveals the complex interplay among cells within the evolving tumor•T cells recruited from lymph nodes are activated and clonally expand in situ•Temporally regulated, functionally distinct stromal populations exist•Cross-compartment interactions can be identified using the CellPhoneDB database,scRNA-seq reveals the complex interplay among cells within the evolving tumor,T cells recruited from lymph nodes are activated and clonally expand in situ,Temporally regulated, functionally distinct stromal populations exist,Cross-compartment interactions can be identified using the CellPhoneDB database,Davidson et al. use scRNA-seq to demonstrate the increasing heterogeneity within the stroma as a tumor develops.,They show that T cell activation occurs at the tumor following recruitment from lymph nodes and reveal the presence of three dynamic stromal populations that display unique functional properties.
The determination of individual cell trajectories through a high-dimensional cell-state space is an outstanding challenge for understanding biological changes ranging from cellular differentiation to epigenetic responses of diseased cells upon drugging.,We integrate experiments and theory to determine the trajectories that single BRAFV600E mutant melanoma cancer cells take between drug-naive and drug-tolerant states.,Although single-cell omics tools can yield snapshots of the cell-state landscape, the determination of individual cell trajectories through that space can be confounded by stochastic cell-state switching.,We assayed for a panel of signaling, phenotypic, and metabolic regulators at points across 5 days of drug treatment to uncover a cell-state landscape with two paths connecting drug-naive and drug-tolerant states.,The trajectory a given cell takes depends upon the drug-naive level of a lineage-restricted transcription factor.,Each trajectory exhibits unique druggable susceptibilities, thus updating the paradigm of adaptive resistance development in an isogenic cell population.,Detailed understanding of how cancer cells transition from a drug sensitive to a tolerant state is lacking.,Here, using single cell proteomic and metabolic data the authors uncover that isogenic BRAF mutant melanoma cells can take two distinct paths to become tolerant to BRAF inhibition.