RESUMO
Tumor-associated macrophages (TAMs) are a heterogeneous population of cells that facilitate cancer progression. However, our knowledge of the niches of individual TAM subsets and their development and function remain incomplete. Here, we describe a population of lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1)-expressing TAMs, which form coordinated multi-cellular "nest" structures that are heterogeneously distributed proximal to vasculature in tumors of a spontaneous murine model of breast cancer. We demonstrate that LYVE-1+ TAMs develop in response to IL-6, which induces their expression of the immune-suppressive enzyme heme oxygenase-1 and promotes a CCR5-dependent signaling axis, which guides their nest formation. Blocking the development of LYVE-1+ TAMs or their nest structures, using gene-targeted mice, results in an increase in CD8+ T cell recruitment to the tumor and enhanced response to chemotherapy. This study highlights an unappreciated collaboration of a TAM subset to form a coordinated niche linked to immune exclusion and resistance to anti-cancer therapy.
Assuntos
Neoplasias , Camundongos , Animais , Neoplasias/patologia , Macrófagos/metabolismoRESUMO
Deciphering the origins of chronic inflammatory and autoimmune diseases remains elusive with reliance on therapies aimed at halting inflammation in its tracks. In recent years, an appreciation of targeting pathways by which inflammation is resolved has begun to rouse interest. Resolution of inflammation is driven by a complex set of mediators that regulate cellular events required to clear inflammatory cells from sites of infection or injury to restore tissue function. However, recent studies suggest that resolution is not the end of innate mediated immune responses to infection/injury. There is further immunological activity occurring after the resolution cascade is complete that alters the immune physiology of tissues, redefining what was once termed restorative homeostasis as adapted homeostasis.
