Effects of vascular normalizing agents on immune marker expression in T cells, dendritic cells, and melanoma cells

Tertiary lymphoid structures (TLS) are lymph node-like structures that form at sites of inflammation, and their presence in cancer patients is predictive of a better clinical outcome. One significant obstacle to TLS formation is reduced immune cell infiltration into the tumor microenvironment (TME), resulting from aberrant vasculature within the TME. Recent studies have shown that low doses of vasculature normalizing (VN) agents may override this defect, leading to improved tissue perfusion and increased immune cell entry into the TME. While the effect of VN agents on vascular endothelial cells has been well documented, their effects on immune cell and tumor cell phenotype remain understudied. We hypothesized that treating immune cells with VN agents would induce a pro-inflammatory phenotype in T cells and dendritic cells (DCs), while treating tumor cells would reduce their immunosuppressive phenotype and promote production of chemokines that recruit immune cells and foster TLS formation. To test this, a mouse melanoma cell line, primary murine T cells, and DCs were treated overnight with VN agents. The next day, treated and control cells were harvested for analyses to measure transcript levels of target genes as well as levels of surface markers. Overall, VN agents were observed to have differential but predominantly immune-supportive effects on immune and tumor cell phenotypes. These findings will guide future experiments which may result in an effective clinical treatment.