CD47 deficiency in tumor stroma promotes tumor progression by enhancing angiogenesis

Area of Science:

• Oncology
• Immunology
• Cell Biology

Background:

• CD47 is a transmembrane protein interacting with thrombospondin-1 (TSP1) and signal-regulatory protein-α (SIRPα).
• Blocking the CD47-SIRPα axis on tumor cells and macrophages can elicit anti-tumor responses.
• The role of CD47 within the tumor stroma remains less understood.

Purpose of the Study:

• To investigate the impact of CD47 expression in tumor stroma on tumorigenesis.
• To compare tumor growth and characteristics in wild-type (WT) and CD47-deficient mice.

Main Methods:

• Subcutaneous injection of syngeneic prostate cancer cells into WT and CD47-deficient mice.
• Analysis of tumor growth, angiogenesis, vascular integrity, necrosis, and immune cell infiltration.
• Assessment of vascular endothelial growth factor (VEGF)-A and VEGF receptor 2 (VEGFR2) expression.

Main Results:

• CD47 deficiency in tumor stromal endothelial cells promoted angiogenesis and accelerated tumor progression.
• Tumors in CD47-deficient mice exhibited enhanced vascular integrity and stability with increased VEGF-A and VEGFR2 expression.
• Reduced macrophage recruitment was observed in tumors from CD47-deficient mice, potentially linked to decreased TSP1 production.

Conclusions:

• While blocking CD47-SIRPα signaling can induce anti-tumor immunity, targeting CD47 in tumor stroma may paradoxically promote tumor progression.
• CD47 signaling in tumor stromal endothelial cells plays a critical role in regulating tumor angiogenesis and progression.