Tumor interstitial fluid pressure may regulate angiogenic factors in osteosarcoma

Area of Science:

• Oncology
• Vascular Biology
• Biomedical Engineering

Background:

• Osteosarcomas (OS) exhibit elevated interstitial fluid pressure (IFP), linked to proliferation and chemosensitivity.
• The role of IFP in regulating angiogenesis within OS remains largely unexplored.

Purpose of the Study:

• To investigate the hypothesis that elevated IFP in OS regulates angiogenesis.
• To determine the relationship between IFP, vascularity, and the expression of key angiogenic factors in OS.

Main Methods:

• IFP and blood flow measurements using the wick-in-needle method in 16 OS patients during biopsy.
• Assessment of tumor vascularity via capillary density and immunohistochemical staining for CD31, VEGF-A, VEGF-C, and TPA.
• Validation of clinical findings in a pressurized cell culture system using OS, OB, and HUVEC cell lines.

Main Results:

• OS tumors showed significantly higher IFP (33.5 mmHg) compared to normal tissue (2.9 mmHg).
• Lower vascularity tumors had higher IFP than highly vascularized tumors.
• Pressurized conditions in OS cells led to VEGF-A downregulation, VEGF-C upregulation, and TPA upregulation, with inverse effects in OB cells.

Conclusions:

• Elevated IFP in osteosarcomas is associated with altered expression of angiogenesis-related molecules, including VEGF and TPA.
• IFP may play a regulatory role in osteosarcoma angiogenesis, suggesting potential therapeutic targets.