Immune Cells in Cancer Therapy and Drug Delivery

Figure 2

Immune cells in tumour microenvironment. The figure shows the potential roles of immune cells in tumour immunosurveillance. NK cells activated by cancer cells (cellular stress and low expression of MHC-I and IL-10 and TGF-β) directly recognize and attack cancer cells through at least four mechanisms: cytoplasmic granule release, death receptor-induced apoptosis, effector molecule production, or ADCC. Interaction of NK cells with DCs leads to improving their antigen uptake and presentation, facilitating the generation of antigen-specific T cells responses. Tumour associated neutrophils secrete oncostatin M inducing angiogenesis and invasiveness of tumour cells. Potential direct effect of neutrophils on tumour progression is secretion of matrix metalloproteinase-9 (MMP-9) enzymes. Inhibition of neutrophil influx by interleukin-8 (IL-8) neutralization can decrease tumour angiogenesis and intravasation. Infiltration of macrophages to tumour microenvironment inhibits canonical Wnt signaling leading to decreased proliferation and survival of cancer cells but as “side effect” noncanonical Wnt signaling is activated inducing metastasis. Ab, antibody; ADCC, antibody-dependent cellular cytotoxicity; DC, dendritic cell; IFN, interferon; and NK, natural killer.