Regulation of tumor-infiltrating T cells by macrophages

Project Abstract Tumor-associated macrophages (TAMs), a major component of the tumor stromal mass, demonstrate great phenotypic heterogeneity and diverse functional capabilities under the influence of local tumor microenvironment (TME). These TAMs generally display an anti-inflammatory, M2-type phenotype and can facilitate tumor growth by promoting angiogenesis, invasion and metastasis, as well as immune evasion. However, it remains largely undefined exactly how these TAMs regulate anti-tumor immune responses within the TME. The objective of this application is to understand the role of TAM-derived PD-L1/siglec-15 in inducing intratumoral CD8 T cell dysfunction, to delineate mechanisms underlying PD-L1/siglec-15 upregulation in TAMs as well as to develop novel strategies to promote intratumoral CD8 T cell infiltration and function in favor of enhancing anti-tumor immunity. The long-term objective of this project is to understand signals required for functional polarization of TAMs within the TME, and its contributions to immune cell dysregulations, cancer development and progression, which may lead to the development of novel cancer therapeutic strategies.