Anti‐VEGF‐A therapy reduces lymphatic vessel density and expression of VEGFR‐3 in an orthotopic breast tumor model

Abstract

Because metastasis contributes significantly to cancer mortality, understanding its mechanisms is crucial to developing effective therapy. Metastasis is facilitated by lymphangiogenesis, the growth of new intratumoral or peritumoral lymphatic vessels from pre-existing vessels. Vascular endothelial growth factor A (VEGF-A) is a well-known angiogenic factor. Increasing evidence implicates VEGF-A in lymphangiogenesis, although the mechanism of its pro-lymphangiogenic effect is poorly understood. We examined the effect of the anti-VEGF-A neutralizing antibody 2C3 on tumor lymphangiogenesis and metastasis in an orthotopic breast carcinoma model using MDA-MB-231 cells and its luciferase-tagged derivative, 231-Luc 1 cells. Anti-VEGF-A antibody therapy reduced blood and lymphatic vessel densities by 70% and 80%, respectively, compared with the control antibody. Treatment with 2C3 antibody also decreased incidence of lymphatic and pulmonary metastases by 3.2-and 4.5-fold, respectively. Macrophage infiltration was reduced in 2C3-treated tumors by 32%, but VEGF-C expression was unchanged. In contrast, neoplastic cells and blood vessels in tumors from 2C3-treated mice expressed significantly less angiopoietin-2 (Ang-2) than tumors from control mice. The reduction in Ang-2 was associated with inhibition of VEGFR-3 expression in intratumoral lymphatic endothelial cells. Both VEGF-A and Ang-2 upregulated the expression of VEGFR-3 in cultured lymphatic endothelial cells. VEGF-A induced proliferation of lymphatic endothelial cells was reduced by 50% by soluble Tie-2, suggesting that Ang-2 is an intermediary of the pro-lymphangiogenic VEGF-A effect. These results suggest a novel mechanism by which anti-VEGF-A therapy may suppress tumor lymphangiogenesis and subsequent metastasis supporting the use of anti-VEGF-A therapy to control metastasis clinically.

Overexpression of the RNA binding protein HuR impairs tumor growth in triple negative breast cancer associated with deficient angiogenesis

“…[29][30][31][32] It has also been demonstrated that TSP1 can mediate tumor growth suppression via blocking angiogenesis, consistent with our results. 33,34 As previously mentioned HuR has been described to stabilize TSP1 and VEGF mRNA resulting in greater levels and increased protein expression.…”

E7080 Suppresses Hematogenous Multiple Organ Metastases of Lung Cancer Cells with Nonmutated Epidermal Growth Factor Receptor

“…Double staining for CD31 and LYVE-1 showed that a small population of cells in the periphery was doubly positive for both (Fig. 4B), consistent with previous findings (26,27). Importantly, E7080 treatment dramatically inhibited the numbers of CD31-and LYVE-1-positive cells (Fig.…”

Combination therapy with short interfering RNA vectors against VEGF-C and VEGF-A suppresses lymph node and lung metastasis in a mouse immunocompetent mammary cancer model

“…39 Indeed, inhibition of VEGF-A expression is associated with decreases in tumor lymphangiogenesis and metastasis. 40,41 Moreover, a reduction in metastasis by downregulation of VEGF-A may be responsible for inhibition of angiogenesis and lymphangiogenesis in tumors, prevention of angiogenic switching in micrometastases and blockage of macrophage recruitment. 42,43 AntiVEGF-A therapy reduces lymphatic vessels and expression of VEGFR-3 in an orthotopic breast tumor model, 41 which may be the mechanism for the anti-metastasis effect.…”