Tumour interstitial fluid pressure may regulate angiogenic factors in osteosarcoma

Area of Science:

• Oncology
• Biomedical Engineering
• Vascular Biology

Background:

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

Purpose of the Study:

• To investigate the hypothesis that elevated IFP in osteosarcomas actively regulates angiogenesis.
• To determine the molecular mechanisms by which IFP influences angiogenic factors.

Main Methods:

• IFP and blood flow measurements were taken from 16 osteosarcoma patients during biopsy using the wick-in-needle method.
• Capillary density was assessed in biopsy specimens, alongside immunohistochemical analysis of CD31, VEGF-A, VEGF-C, and TPA.
• In vitro studies utilized pressurized cell culture systems with osteosarcoma, OB, and HUVEC cell lines to validate clinical findings.

Main Results:

• Tumor IFP (mean 33.5 mmHg) was significantly higher than in normal tissue (2.9 mmHg).
• Higher IFP correlated with lower tumor vascularity (P < 0.001).
• Pressurized conditions in osteosarcoma cells led to VEGF-A downregulation, VEGF-C upregulation, and TPA upregulation, consistent with immunohistochemical results.

Conclusions:

• Interstitial fluid pressure (IFP) appears to be a significant regulator of specific molecules involved in angiogenesis within osteosarcomas.
• These findings suggest IFP as a potential therapeutic target for modulating tumor vascularization.