Tumor macrophages as a target for Capsaicin mediated immunotherapy

Tumor microenvironment contributes to a large extent for failure of immunological destruction of antigenic tumors. Most solid tumors adapt to the microenvironment and escape the host immune system. The dramatic and systemic effectiveness of neuro-immune ligand Capsaicin (CP) in regression of established solid tumors led us to investigate its immunomodulatory role in tumor microenvironment. In this report we demonstrate that CP induced tumor cell apoptosis leads to increased sensitization of the surrounding stroma manifested by enhanced antigen presentation by stromal macrophages and its destruction by tumor specific T-cells. Further, CP injection alters the tumor microenvironment with regards to tumor-infiltrating Treg cells as well as the cytokine milieu at the tumor site. Our data collectively demonstrates that injection of CP sets in motion, a cascade of several independent innate and adaptive immunological events initiated at the tumor environment.