We present a new foundational role for CXCR3 + monocytes/macrophages in the process of tumor engraftment in the lung. CXCR3 is associated with monocytic and lymphocytic infiltration of inflamed or tumor-bearing lung. Although the requirement for tumor-expressed CXCR3 in metastatic engraftment has been demonstrated, the role of monocyte-expressed CXCR3 had not been appreciated. In a murine model of metastatic-like melanoma, engraftment was coordinate with CXCR3 + monocyte/macrophage accumulation in the lungs and was sensitive to pharmacologic inhibition of CXCR3 signaling. Tumor engraftment to lung was impaired in CXCR3 − / − mice, and transient reconstitution with circulating CXCR3-replete monocytes was sufficient to restore engraftment. These data illustrate the paradoxical pro-tumor role for CXCR3 in lung immunobiology wherein the CXCR3 axis drives both the anti- tumor effector cell chemoattraction and pro-tumor infiltration of the lungs and suggests a potential therapeutic target for lung-tropic metastasizing cancers.
Butler, Kiah L.; Clancy-Thompson, Eleanor; and Mullins, David W., "Cxcr3+ Monocytes/Macrophages are Required for Establishment of Pulmonary Metastases" (2017). Open Dartmouth: Faculty Open Access Articles. 2603.