Tumor Immunotherapy by Utilizing a Double-Edged Sword, Chemokines

Both innate and adaptive immune responses have an essential role in protection against tumor cells. Various types of immune cells such as dendritic cells and lymphocytes contribute to the establishment of immune responses to tumor cells. Chemokines, a family consisting of more than 40 related chemoattractant proteins, have a crucial role in the control of the recruitment of immune cells needed for the induction and activation of tumor immunity. Based on these properties, several chemokines have been utilized in preclinical models to augment tumor immunity by enhancing the migration and activation of immune cells. Paradoxically, tumor tissues use chemokines to evade immunosurveillance by attracting immune suppressive cells. Moreover, chemokines can mediate survival and migration of tumor cells and promote new blood vessel formation, thereby leading to tumor progression and metastasis. Thus, a number of therapeutic strategies have been proposed to target chemokines, in order to reduce tumor progression and metastasis, although these strategies have not yet been translated to clinical situations. Here, we will briefly summarize the preclinical results obtained by using and/or targeting chemokines to combat tumors and discuss the potential efficacy of these methods.