Protocol to identify and isolate rare murine tumor-resident dendritic cell populations for low-input transcriptomic profiling.

Conventional type 1 dendritic cells (cDC1s) are critical for innate sensing of cancer, yet they are scarce in the tumor microenvironment (TME). Here, we present a protocol to identify and isolate cDC1 subsets from murine implantable tumors for subsequent transcriptomic profiling using a flow sorting-based strategy. We describe steps for cell culture of mouse tumors, tumoral growth, dissociation and isolation of tumoral cells, extracellular staining, and cell sorting.

Emerging roles for tumor stroma in antigen presentation and anti-cancer immunity.

Advances in immunotherapy in the last decade have revolutionized treatment paradigms across multiple cancer diagnoses. However, only a minority of patients derive durable benefit and progress with traditional approaches, such as cancer vaccines, remains unsatisfactory. A key to overcoming these barriers resides with a deeper understanding of tumor antigen presentation and the complex and dynamic heterogeneity of tumor-infiltrating antigen-presenting cells (APCs).

Stromal remodeling regulates dendritic cell abundance and activity in the tumor microenvironment.

Stimulatory type 1 conventional dendritic cells (cDC1s) engage in productive interactions with CD8 effectors along tumor-stroma boundaries. The paradoxical accumulation of "poised" cDC1s within stromal sheets is unlikely to simply reflect passive exclusion from tumor cores. Drawing parallels with embryonic morphogenesis, we hypothesized that invasive margin stromal remodeling generates developmentally conserved cell fate cues that regulate cDC1 behavior.

Matrix proteoglycans in tumor inflammation and immunity.

Cancer immunoediting progresses through elimination, equilibrium, and escape. Each of these phases is characterized by breaching, remodeling, and rebuilding tissue planes and structural barriers that engage extracellular matrix (ECM) components, in particular matrix proteoglycans. Some of the signals emanating from matrix proteoglycan remodeling are readily co-opted by the growing tumor to sustain an environment of tumor-promoting and immune-suppressive inflammation.