title: Tumor interstitial fluid pressure may regulate angiogenic factors in osteosarcoma.
abstract: We have previously shown that osteosarcomas (OS) have states of increased interstitial fluid pressure (IFP), which correlate with increased proliferation and chemosensitivity. In this study, we hypothesized that constitutively raised IFP in OS regulates angiogenesis. Sixteen patients with the clinical diagnosis of OS underwent blood flow and IFP readings by the wick-in-needle method at the time and location of open biopsy. Vascularity was determined by capillary density in the biopsy specimens. We performed digital image analysis of immunohistochemical staining for CD31, VEGF-A, VEGF-C, and TPA on paraffin-embedded tissue blocks of the biopsy samples. Clinical results were validated in a pressurized cell culture system. Interstitial fluid pressures in the tumors (mean 33.5 +/- SD 17.2 mmHg) were significantly higher (p = 0.00001) than that in normal tissue (2.9 +/- 5.7 mmHg). Pressure readings were significantly higher in low vascularity tumors compared to high vascularity tumors (p < 0.001). In the OS cell lines, growth in a pressurized environment was associated with VEGF-A downregulation, VEGF-C upregulation, and TPA upregulation. The reverse was seen in the OB cell line. Growth in the HUVEC cell line was not significantly inhibited in a pressurized environment. Immunohistochemical assessment for VEGF-A (p = 0.01), VEGF-C (p = 0.008), and TPA (p = 0.0001) translation were consistent with the findings on PCR. Our data suggests that some molecules in angiogenesis are regulated by changes in IFP.
authors.affiliation: Musculoskeletal Oncology Service, Department of Orthopaedic Surgery, Yong Loo Lin School of Medicine, National University of Singapore, 5, Lower Kent Ridge Road, Singapore 119074, Singapore.
authors.forename: Saminathan S
authors.initials: SS
authors.lastname: Nathan
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Huvos
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Casas-Ganem
authors.forename: Rui
authors.initials: R
authors.lastname: Yang
authors.forename: Irina
authors.initials: I
authors.lastname: Linkov
authors.forename: Rebecca
authors.initials: R
authors.lastname: Sowers
authors.forename: Gene R
authors.initials: GR
authors.lastname: DiResta
authors.forename: Richard
authors.initials: R
authors.lastname: Gorlick
authors.forename: John H
authors.initials: JH
authors.lastname: Healey
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000378:metabolism; D001859:Bone Neoplasms / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D004730:Endothelium, Vascular / Q000378:metabolism; D045604:Extracellular Fluid / Q000378:metabolism*; D005260:Female; D019085:Fluorescent Antibody Technique, Direct; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D006874:Hydrostatic Pressure; D007091:Image Processing, Computer-Assisted; D042583:Lymphangiogenesis / Q000502:physiology; D008297:Male; D008833:Microcirculation / Q000378:metabolism / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000378:metabolism*; D012516:Osteosarcoma / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology; D042582:Vascular Endothelial Growth Factor C / Q000235:genetics / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D042582:Vascular Endothelial Growth Factor C