Contribution of Host-Derived Tissue Factor to Tumor Neovascularization

Abstract

Objective-The role of host-derived tissue factor (TF) in tumor growth, angiogenesis, and metastasis has hitherto been unclear and was investigated in this study. Methods and Results-We compared tumor growth, vascularity, and responses to cyclophosphamide (CTX) of tumors in wild-type (wt) mice, or in animals with TF levels reduced by 99% (low-TF mice). Global growth rate of 3 different types of transplantable tumors (LLC, B16F1, and ES teratoma) or metastasis were unchanged in low-TF mice. However, several unexpected tumor/context-specific alterations were observed in these mice, including: (1) reduced tumor blood vessel size in B16F1 tumors; (2) larger spleen size and greater tolerance to CTX toxicity in the LLC model; (3) aborted tumor growth after inoculation of TF-deficient tumor cells (ES TF Ϫ/Ϫ ) in low-TF mice. TF-deficient tumor cells grew readily in mice with normal TF levels and attracted exclusively host-related blood vessels (without vasculogenic mimicry). We postulate that this complementarity may result from tumor-vascular transfer of TF-containing microvesicles, as we observed such transfer using human cancer cells (A431) and mouse endothelial cells, both in vitro and in vivo.

Embryonic stem cell tumor model reveals role of vascular endothelial receptor tyrosine phosphatase in regulating Tie2 pathway in tumor angiogenesis

“…In addition, studies of teratomas generated from human ES cells have noted the formation of structures with markers of lymphatic vessels (16), although, similar to the current study, the frequency of such structures was low. Previous studies have also noted the existence of ES-derived vascular endothelial cells in teratomas (16,29), although another study was unable to detect such cells (30). In our studies, the use of endothelial cell-specific ␤-gal reporter allowed for unambiguous identification of robust vascular networks throughout the teratomas, as well as in-depth comparisons of ES-derived vessels versus host-derived vessels.…”

Cancer Cells Induced to Express Mesenchymal Phenotype Release Exosome-like Extracellular Vesicles Carrying Tissue Factor

“…Containing TF-A431 cells are known to emit both EGFR and TF via the vesiculation pathway (17,26). In this regard, the EV content of EGFR did not change significantly as a function of various treatments (Fig.…”

“…Membrane Labeling with PKH26 and Flow Cytometry-A431 cells were surface labeled with PKH26 (red fluorescent dye; Sigma) as per manufacturer's instructions (26). EVs from labeled A431 cells were incubated for 24 h with HUVEC, and the fluorescence uptake was detected using FACSCalibur flow cytometer (BD Biosciences).…”

“…The EGFR/Ecadherin pathway regulates mesenchymal phenotype in some of these cells and may shift TF release toward small exosomelike particles. 26). To assess whether TF-containing EVs generated by A431 cells under epithelial or mesenchymal culture conditions differ in this regard, we incubated HUVEC with these EVs and tested for their overall EV uptake, as well as transfer of the TF antigen and procoagulant activity (Fig.…”

Molecular subtypes and differentiation programmes of glioma stem cells as determinants of extracellular vesicle profiles and endothelial cell‐stimulating activities

“…EVs isolated from cells were labelled with PKH26 (#MINI26, Sigma-Aldrich) red fluorescent dye as described earlier [33,34]. Briefly, EVs were re-suspended in 250 μL of 2× Diluent C. The 2 × Dye Solution (4 × 10 –6  M) in Diluent C is prepared by adding 1 μL of the PKH26 ethanolic dye solution (# P9691) to 250 mL of Diluent C in a polypropylene centrifuge tube and mixed well to disperse.…”