METHODS TO STUDY MYELOID CELL ROLES IN ANGIOGENESIS

Tumor growth and metastasis depend on neovascularization, the growth of new blood vessels. Recent studies have found that bone marrow derived cells contribute to angiogenesis during tumor growth and inflammation. Tumor neovascularization is regulated in part by monocytes, which are myeloid lineage cells from the bone marrow. Tumors exhibit significant monocyte infiltrates, and recent studies indicate that monocytes are actively recruited to the tumor microenvironment. Upon tumor infiltration, monocytes can participate in tumor neovascularization by differentiating into M2 macrophages, which express proangiogenic growth factors. By understanding how bone marrow-derived cells contribute to tumor growth, it may be possible to develop new approaches to cancer therapy. In this chapter, we discuss experimental methods to examine the roles of myeloid cells in tumor growth and angiogenesis, including methods to identify, isolate, purify, and characterize bone marrow-derived monocytes. We also outline methods to analyze the in vivo roles of myeloid cells in tumor growth and angiogenesis using adoptive transfer, bone marrow transplantation, tumor models and immunohistochemistry for markers of vessels and myeloid cells. Finally, we review methods to characterize myeloid cell trafficking in vitro and in vivo.