Pericytes and endothelial precursor cells: cellular interactions and contributions to malignancy

Area of Science:

• Oncology
• Cell Biology
• Vascular Biology

Background:

• Tumor vasculature is critical for growth, with pericytes and endothelial precursor cells (EPC) playing key roles in angiogenesis.
• In culture, pericytes and EPC exhibit similar angiogenic properties and responses to kinase inhibitors.
• Distinct cell surface markers and molecular profiles differentiate pericytes from EPC.

Purpose of the Study:

• To investigate the role of pericytes and EPC in breast cancer malignancy.
• To compare the characteristics and functions of pericytes and EPC in tumor development.
• To evaluate the potential of pericytes and EPC as models for studying tumor vascularization and therapeutic agent selection.

Main Methods:

• Co-culture assays of MDA-MB-231 breast cancer cells with pericytes or EPC.
• Subcutaneous co-injection of live or irradiated pericytes/EPC with cancer cells in vivo.
• Analysis of tumor growth rates, microvessel density, and immunohistochemical staining of vasculature.
• Assessment of lymphatic vessel formation in tumors.

Main Results:

• Pericytes and EPC enhanced MDA-MB-231 cell invasion in co-culture systems.
• Live pericytes/EPC significantly increased tumor growth rates compared to irradiated cells.
• No difference in microvessel density was observed, but EPC/pericytes appeared to stabilize vasculature.
• Tumors co-injected with EPC showed increased lymphatic vessel development.

Conclusions:

• Pericytes and EPC contribute to cancer malignancy and tumor progression.
• These cells may normalize or stabilize existing tumor vasculature rather than initiate new vessel formation.
• Pericytes and EPC serve as valuable cell-based models for understanding tumor vascular development and identifying therapeutic targets.