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Quantitative fluorescent profiling of VEGFRs reveals tumor cell and endothelial cell heterogeneity in breast cancer xenografts.

Imoukhuede PI, Popel AS - Cancer Med (2014)

Bottom Line: Plasma membrane-localized vascular endothelial growth factor receptors (VEGFR) play a critical role in transducing VEGF signaling toward pro and antiangiogenic outcomes and quantitative characterization of these receptors is critical toward identifying biomarkers for antiangiogenic therapies, understanding mechanisms of action of antiangiogenic drugs, and advancing predictive computational models.Furthermore, when these ex vivo data are compared to in vitro data, we observe little to no VEGFRs on MDA-MB-231 cells, and the MDA-MB-231 VEGFR surface levels are not regulated by a saturating dose of VEGF.Overall, the quantification of these dissimilarities for the first time in tumor provides insight into the balance of modulatory (VEGFR1) and proangiogenic (VEGFR2) receptors.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, University of Illinois at Urbana Champaign, Urbana, Illinois, 61801.

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Ensemble-averaged time course of vascular endothelial growth factor receptor (VEGFR) surface distribution. (A) Tumor cells show significantly higher levels of VEGFR1 compared to VEGFR2. For a given VEGFR, the surface levels are not significantly different early in tumor development, 3 weeks, compared late in tumor development, 6 weeks. (B) Tumor endothelial cells show significant differences in VEGFR1 surface levels early in tumor development, 3 weeks, with nearly ∼15,000 VEGFR1/tEC. These levels are nearly halved late in tumor development, 6 weeks. The levels of VEGFR1/tEC at 3 and 6 weeks are significantly different from one another, and are also significantly different from the levels of VEGFR1 found to endothelial cells obtained from normal mouse skeletal muscle. The levels of VEGFR2 on tumor endothelial cells are not significantly different at 3 and 6 weeks, or on endothelial cells isolated from normal mouse skeletal muscle.*P < 0.05; **0.001< P <0.01; ***P < 0.001.
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fig07: Ensemble-averaged time course of vascular endothelial growth factor receptor (VEGFR) surface distribution. (A) Tumor cells show significantly higher levels of VEGFR1 compared to VEGFR2. For a given VEGFR, the surface levels are not significantly different early in tumor development, 3 weeks, compared late in tumor development, 6 weeks. (B) Tumor endothelial cells show significant differences in VEGFR1 surface levels early in tumor development, 3 weeks, with nearly ∼15,000 VEGFR1/tEC. These levels are nearly halved late in tumor development, 6 weeks. The levels of VEGFR1/tEC at 3 and 6 weeks are significantly different from one another, and are also significantly different from the levels of VEGFR1 found to endothelial cells obtained from normal mouse skeletal muscle. The levels of VEGFR2 on tumor endothelial cells are not significantly different at 3 and 6 weeks, or on endothelial cells isolated from normal mouse skeletal muscle.*P < 0.05; **0.001< P <0.01; ***P < 0.001.

Mentions: Although it is apparent that the isolated cells display significant heterogeneity, trends can be observed from the ensemble-averaged data. The large cells show: consistently low levels of VEGFRs; tECs having a higher average surface-VEGFRs compared to the tumor cells; and the highest VEGFR-surface levels are seen at week 6 (Table 3). The small cells have a higher average level of VEGFRs compared to the large cells (Tables 3 and 4). The small tEC have a higher average surface-VEGFRs compared to the small tumor cells (Table 4). VEGFRs on the small tumor cells remain approximately constant at weeks 3 and 6 (Fig. 7A). However, early-stage tumors (week 3) present significantly higher surface VEGFR1 on small tEC, ∼15,000 surface-VEGFR1/tEC when compared to week 6, where VEGFR1 surface levels are reduced by 45% on small tEC to 8150 surface-VEGFR1/tEC (Fig. 7B). Overall, the average levels of VEGFR2 on small tEC are between ∼1200 and 1700 surface-VEGFR2/tEC at weeks 3 and 6 (Fig. 7B), and they are in fact similar to the surface levels of VEGFR2 on endothelial cells derived from mouse skeletal muscle, ∼1100–1700 surface-VEGFR2/EC 41.


Quantitative fluorescent profiling of VEGFRs reveals tumor cell and endothelial cell heterogeneity in breast cancer xenografts.

Imoukhuede PI, Popel AS - Cancer Med (2014)

Ensemble-averaged time course of vascular endothelial growth factor receptor (VEGFR) surface distribution. (A) Tumor cells show significantly higher levels of VEGFR1 compared to VEGFR2. For a given VEGFR, the surface levels are not significantly different early in tumor development, 3 weeks, compared late in tumor development, 6 weeks. (B) Tumor endothelial cells show significant differences in VEGFR1 surface levels early in tumor development, 3 weeks, with nearly ∼15,000 VEGFR1/tEC. These levels are nearly halved late in tumor development, 6 weeks. The levels of VEGFR1/tEC at 3 and 6 weeks are significantly different from one another, and are also significantly different from the levels of VEGFR1 found to endothelial cells obtained from normal mouse skeletal muscle. The levels of VEGFR2 on tumor endothelial cells are not significantly different at 3 and 6 weeks, or on endothelial cells isolated from normal mouse skeletal muscle.*P < 0.05; **0.001< P <0.01; ***P < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig07: Ensemble-averaged time course of vascular endothelial growth factor receptor (VEGFR) surface distribution. (A) Tumor cells show significantly higher levels of VEGFR1 compared to VEGFR2. For a given VEGFR, the surface levels are not significantly different early in tumor development, 3 weeks, compared late in tumor development, 6 weeks. (B) Tumor endothelial cells show significant differences in VEGFR1 surface levels early in tumor development, 3 weeks, with nearly ∼15,000 VEGFR1/tEC. These levels are nearly halved late in tumor development, 6 weeks. The levels of VEGFR1/tEC at 3 and 6 weeks are significantly different from one another, and are also significantly different from the levels of VEGFR1 found to endothelial cells obtained from normal mouse skeletal muscle. The levels of VEGFR2 on tumor endothelial cells are not significantly different at 3 and 6 weeks, or on endothelial cells isolated from normal mouse skeletal muscle.*P < 0.05; **0.001< P <0.01; ***P < 0.001.
Mentions: Although it is apparent that the isolated cells display significant heterogeneity, trends can be observed from the ensemble-averaged data. The large cells show: consistently low levels of VEGFRs; tECs having a higher average surface-VEGFRs compared to the tumor cells; and the highest VEGFR-surface levels are seen at week 6 (Table 3). The small cells have a higher average level of VEGFRs compared to the large cells (Tables 3 and 4). The small tEC have a higher average surface-VEGFRs compared to the small tumor cells (Table 4). VEGFRs on the small tumor cells remain approximately constant at weeks 3 and 6 (Fig. 7A). However, early-stage tumors (week 3) present significantly higher surface VEGFR1 on small tEC, ∼15,000 surface-VEGFR1/tEC when compared to week 6, where VEGFR1 surface levels are reduced by 45% on small tEC to 8150 surface-VEGFR1/tEC (Fig. 7B). Overall, the average levels of VEGFR2 on small tEC are between ∼1200 and 1700 surface-VEGFR2/tEC at weeks 3 and 6 (Fig. 7B), and they are in fact similar to the surface levels of VEGFR2 on endothelial cells derived from mouse skeletal muscle, ∼1100–1700 surface-VEGFR2/EC 41.

Bottom Line: Plasma membrane-localized vascular endothelial growth factor receptors (VEGFR) play a critical role in transducing VEGF signaling toward pro and antiangiogenic outcomes and quantitative characterization of these receptors is critical toward identifying biomarkers for antiangiogenic therapies, understanding mechanisms of action of antiangiogenic drugs, and advancing predictive computational models.Furthermore, when these ex vivo data are compared to in vitro data, we observe little to no VEGFRs on MDA-MB-231 cells, and the MDA-MB-231 VEGFR surface levels are not regulated by a saturating dose of VEGF.Overall, the quantification of these dissimilarities for the first time in tumor provides insight into the balance of modulatory (VEGFR1) and proangiogenic (VEGFR2) receptors.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, University of Illinois at Urbana Champaign, Urbana, Illinois, 61801.

Show MeSH
Related in: MedlinePlus