A xenograft model for venous malformation.

Area of Science:

• Vascular Biology
• Oncology
• Genetics

Background:

• Vascular malformations (VMs) are abnormal vessel growths causing disfigurement and pain.
• Current VM treatments are limited, often relying on supportive care or surgery.
• Somatic mutations in TIE2 and PIK3CA genes are implicated in VM development.

Purpose of the Study:

• To develop a xenograft model of VM that reflects patient mutation heterogeneity.
• To characterize the signaling pathways affected by TIE2 and PIK3CA mutations in VM endothelial cells.
• To establish a preclinical platform for evaluating targeted therapies for VMs.

Main Methods:

• Isolated and cultured endothelial cells (VM-ECs) from nine VM patients.
• Genotyped VM-ECs for TIE2, PIK3CA, or combined mutations.
• Implanted VM-ECs into immune-deficient mice to create xenograft VM lesions.
• Analyzed signaling pathways (AKT, MAPK-ERK) in VM-ECs.

Main Results:

• VM-ECs harbored TIE2, PIK3CA, or combined mutations.
• Both mutation types induced constitutive AKT activation; TIE2 mutations also activated MAPK-ERK signaling.
• Xenograft lesions resembled human VMs with ectatic, blood-filled channels and poor smooth muscle coverage.

Conclusions:

• The developed VM xenograft model accurately recapitulates human VM pathology and mutation profiles.
• This model provides a valuable tool for testing Sirolimus and other targeted therapies.
• It facilitates the development of personalized treatment strategies for venous malformations based on specific genetic mutations.