Figure 13. Model of efferocytosis-induced prostate cancer tumor growth in the bone microenvironment.

Bone macrophages (MΦs) engage and efferocytose apoptotic cancer cells to induce the activation of Stat3 and NF-κB(p65), which stimulate the production of proinflammatory cytokines including CCL5, CXCL1, IL-6, and CXCL5. CXCL5 is a crucial chemoattractant of inflammatory myeloid cells, including CD11b⁺Gr-1⁺, Ly6B⁺ cells, and increases M2 (F4/80⁺CD206⁺ cells) polarization, all resulting in perpetual inflammation and immunosuppression that stimulate tumor growth. OC, osteoclast; OB, osteoblast.