Murine mammary carcinoma cells and CD11c(+) dendritic cells elicit distinct responses to lipopolysaccharide and exhibit differential expression of genes required for TLR4 signaling.

Although TLR are often studied on DC because of their ability to bridge innate and adaptive defenses, TLR are also expressed by epithelial cells. Because the majority of cancers are carcinomas, and thus of epithelial origin, we wanted to know whether a carcinoma and DC responded similarly to a TLR agonist. We found the mammary carcinoma 4T1 and CD11c(+) DC both secreted proinflammatory chemokines in response to the TLR4 agonist lipopolysaccharide (LPS).