title: Recruitment of monocytes/macrophages in different tumor microenvironments.
abstract: After emigration from the bone marrow into the peripheral blood, monocytes enter tissues and differentiate into macrophages. Monocytes/macrophages have many roles in immune regulation, angiogenesis, and tumor metastasis and invasion. In addition, studies have revealed that these cells are essential to tumor progression. Recently, an accumulation of evidence has indicated that macrophages in distinct regions of tumor masses have distinct origins. For instance, classical monocytes appear to be a major source of macrophages in tumor epithelial, perivascular, and hypoxic regions. In contrast, non-classical monocytes are an important source of macrophages in the tumor perivascular region. During the past century, it has been demonstrated that several chemoattractants can regulate the recruitment of monocytes/macrophages to tumor sites. Despite the importance of monocytes/macrophages in tumor progression, there had been, until recently, no efforts to summarize receptor-ligand pairs between tumor-derived chemokines and corresponding receptors in monocytes in different microenvironments. In this review, we present a cohesive view of the distinct expression patterns of chemokine receptors in two different monocyte subsets (classical and non-classical monocytes) and describe their roles in monocyte/macrophage recruitment into distinct tumor microenvironments. This review provides insight into the behavior of monocytes/macrophages in different tumor microenvironments.
authors.affiliation: Department of Biochemistry, Yonsei University, Seoul, Republic of Korea.
authors.forename: Heon-Woo
authors.initials: HW
authors.lastname: Lee
authors.forename: Hyun-Jung
authors.initials: HJ
authors.lastname: Choi
authors.forename: Sang-Jun
authors.initials: SJ
authors.lastname: Ha
authors.forename: Kyung-Tae
authors.initials: KT
authors.lastname: Lee
authors.forename: Young-Guen
authors.initials: YG
authors.lastname: Kwon
mesh_terms: D000818:Animals; D000073883:CX3C Chemokine Receptor 1; D002465:Cell Movement; D016764:Cell Polarity; D018932:Chemokine CCL2 / Q000502:physiology; D054428:Chemokine CX3CL1 / Q000502:physiology; D006801:Humans; D019041:L-Selectin / Q000502:physiology; D008264:Macrophages / Q000502:physiology*; D009000:Monocytes / Q000502:physiology*; D009369:Neoplasms / Q000473:pathology*; D019707:Receptors, Chemokine / Q000502:physiology; D059016:Tumor Microenvironment; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology
chemical_list: D000073883:CX3C Chemokine Receptor 1; C095235:CX3CR1 protein, human; D018932:Chemokine CCL2; D054428:Chemokine CX3CL1; D019707:Receptors, Chemokine; D042461:Vascular Endothelial Growth Factor A; D019041:L-Selectin