Hypoxia-induced endothelial progenitor cell function is blunted in angiotensinogen knockout mice

Area of Science:

• Molecular Biology
• Oncology
• Cardiovascular Research

Background:

• Angiotensinogen (AGT) is implicated in tumor angiogenesis and atherosclerosis.
• The role of AGT in endothelial progenitor cells (EPCs) regarding tumor progression is not fully understood.

Purpose of the Study:

• To investigate the function of AGT in EPCs during tumor progression and metastasis.
• To elucidate the molecular mechanisms by which AGT influences EPCs and tumor vascularization.

Main Methods:

• Comparative analysis of AGT heterozygous knockout (AGT(+/-)) and wild-type (WT) EPCs.
• Assessment of EPC colony formation, migration, and tube formation abilities.
• Gene expression analysis of key angiogenic and signaling factors (VEGF, SDF-1, HIFs, eNOS).
• In vivo studies using AGT(+/-) mice to evaluate tumor growth and metastasis.

Main Results:

• AGT(+/-) EPCs exhibited reduced colony formation, migration, and tube formation compared to WT EPCs.
• Expressions of VEGF, SDF-1, HIF-1α, HIF-2α, and eNOS were significantly downregulated in AGT(+/-) EPCs.
• Activation of Akt/eNOS signaling pathways was suppressed in AGT(+/-) EPCs.
• Tumor vascularization, lung tumor growth, and melanoma metastasis were attenuated in AGT(+/-) mice.

Conclusions:

• AGT plays a critical role in EPC function, essential for hypoxia-induced vasculogenesis.
• AGT deficiency impairs EPCs, leading to reduced tumor angiogenesis, growth, and metastasis.
• Targeting AGT may offer a therapeutic strategy for inhibiting tumor progression and metastasis.