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Stat3 orchestrates interaction between endothelial and tumor cells and inhibition of Stat3 suppresses brain metastasis of breast cancer cells.

Lee HT, Xue J, Chou PC, Zhou A, Yang P, Conrad CA, Aldape KD, Priebe W, Patterson C, Sawaya R, Xie K, Huang S - Oncotarget (2015)

Bottom Line: WP1066 inhibited Stat3 activation in tumor-associated endothelial cells, reducing their infiltration and angiogenesis.WP1066 also inhibited breast cancer cell invasion.Our results indicate that WP1066 can inhibit tumor angiogenesis and brain metastasis mediated by Stat3 in endothelial and tumor cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.

ABSTRACT
Brain metastasis is a major cause of morbidity and mortality in patients with breast cancer. Our previous studies indicated that Stat3 plays an important role in brain metastasis. Here, we present evidence that Stat3 functions at the level of the microenvironment of brain metastases. Stat3 controlled constitutive and inducible VEGFR2 expression in tumor-associated brain endothelial cells. Furthermore, inhibition of Stat3 by WP1066 decreased the incidence of brain metastases and increased survival in a preclinical model of breast cancer brain metastasis. WP1066 inhibited Stat3 activation in tumor-associated endothelial cells, reducing their infiltration and angiogenesis. WP1066 also inhibited breast cancer cell invasion. Our results indicate that WP1066 can inhibit tumor angiogenesis and brain metastasis mediated by Stat3 in endothelial and tumor cells.

No MeSH data available.


Related in: MedlinePlus

WP1066 inhibits the invasion and migration ability of bEnd.3 cells(A) Cytotoxicity of WP1066 in bEnd.3 cells by MTT assay. bEnd.3 cells were treated with various concentrations of WP1066 or with DMSO for 72 hours. Values are means ± SD for triplicate experiments. *, P<0.1; #, P<0.001. (B) bEnd.3 cells were treated with vehicle or WP1066 1 μM in CM of MDA-MB-231BR cells. Protein expression of VEGFR-2, pVEGFR-2, and β-actin was analyzed by immunoblotting. (C) bEnd.3 cells were cultured with serum-free medium or CM from MDA-MB-231BR cells treated with vehicle or WP1066 1 μM. Then migration ability was determined using the migration assay at 12 hours. Left panels, representative photos of the results. Right panel, quantification of results. Each column indicates the mean ± SD from results of three different experiments. **, P<0.01; ***, P<0.001. (D) bEnd.3 cells were cultured medium as described in (C). Then invasiveness was determined using the invasion assay at 16 hours. Left panels, representative photos of the results. Right panel, quantification of results. Each column indicates the mean ± SD from results of three different experiments. **, P<0.01; ***, P<0.001. (E) Stat3 regulates breast cancer cell brain metastasis by affecting interaction between tumor cells and endothelial cells and tumor cell invasive. Activated Stat3 in tumor cells upregulates the expression of VEGF that induces the phosphorylation of VEGFR2 in endothelial cells. The phosphorylated VEGFR2 leads to phosphorylation hence activation of Stat3 in endothelial cells. Then the activated Stat3 directly upregulates VEGFR2 expression in endothelial cells, which leads to further activation of VEGFR2 in the cells, increasing their infiltration and angiogenesis. Therefore, Stat3 activation orchestrates the interaction between endothelial and tumor cells. Stat3 also directly regulates MMP-9 expression hence breast cancer cell and endothelial invasion. WP1066 can effectively inhibit tumor angiogenesis and invasion thus brain metastasis mediated by Stat3.
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Figure 6: WP1066 inhibits the invasion and migration ability of bEnd.3 cells(A) Cytotoxicity of WP1066 in bEnd.3 cells by MTT assay. bEnd.3 cells were treated with various concentrations of WP1066 or with DMSO for 72 hours. Values are means ± SD for triplicate experiments. *, P<0.1; #, P<0.001. (B) bEnd.3 cells were treated with vehicle or WP1066 1 μM in CM of MDA-MB-231BR cells. Protein expression of VEGFR-2, pVEGFR-2, and β-actin was analyzed by immunoblotting. (C) bEnd.3 cells were cultured with serum-free medium or CM from MDA-MB-231BR cells treated with vehicle or WP1066 1 μM. Then migration ability was determined using the migration assay at 12 hours. Left panels, representative photos of the results. Right panel, quantification of results. Each column indicates the mean ± SD from results of three different experiments. **, P<0.01; ***, P<0.001. (D) bEnd.3 cells were cultured medium as described in (C). Then invasiveness was determined using the invasion assay at 16 hours. Left panels, representative photos of the results. Right panel, quantification of results. Each column indicates the mean ± SD from results of three different experiments. **, P<0.01; ***, P<0.001. (E) Stat3 regulates breast cancer cell brain metastasis by affecting interaction between tumor cells and endothelial cells and tumor cell invasive. Activated Stat3 in tumor cells upregulates the expression of VEGF that induces the phosphorylation of VEGFR2 in endothelial cells. The phosphorylated VEGFR2 leads to phosphorylation hence activation of Stat3 in endothelial cells. Then the activated Stat3 directly upregulates VEGFR2 expression in endothelial cells, which leads to further activation of VEGFR2 in the cells, increasing their infiltration and angiogenesis. Therefore, Stat3 activation orchestrates the interaction between endothelial and tumor cells. Stat3 also directly regulates MMP-9 expression hence breast cancer cell and endothelial invasion. WP1066 can effectively inhibit tumor angiogenesis and invasion thus brain metastasis mediated by Stat3.

Mentions: The above results indicated that Stat3 activity regulated VEGFR-2 in brain endothelial cells and hence regulated their activation, thus, we examined whether WP1066 has direct cytotoxic effects on brain endothelial cells. WP1066 at low concentrations (1-3 μM) was not cytotoxic to bEnd.3 cells (Fig. 6A). However, a low concentration of WP1066 (1 μM) inhibited the activation of brain endothelial cells induced by brain metastatic breast cancer cells (Fig. 6B).


Stat3 orchestrates interaction between endothelial and tumor cells and inhibition of Stat3 suppresses brain metastasis of breast cancer cells.

Lee HT, Xue J, Chou PC, Zhou A, Yang P, Conrad CA, Aldape KD, Priebe W, Patterson C, Sawaya R, Xie K, Huang S - Oncotarget (2015)

WP1066 inhibits the invasion and migration ability of bEnd.3 cells(A) Cytotoxicity of WP1066 in bEnd.3 cells by MTT assay. bEnd.3 cells were treated with various concentrations of WP1066 or with DMSO for 72 hours. Values are means ± SD for triplicate experiments. *, P<0.1; #, P<0.001. (B) bEnd.3 cells were treated with vehicle or WP1066 1 μM in CM of MDA-MB-231BR cells. Protein expression of VEGFR-2, pVEGFR-2, and β-actin was analyzed by immunoblotting. (C) bEnd.3 cells were cultured with serum-free medium or CM from MDA-MB-231BR cells treated with vehicle or WP1066 1 μM. Then migration ability was determined using the migration assay at 12 hours. Left panels, representative photos of the results. Right panel, quantification of results. Each column indicates the mean ± SD from results of three different experiments. **, P<0.01; ***, P<0.001. (D) bEnd.3 cells were cultured medium as described in (C). Then invasiveness was determined using the invasion assay at 16 hours. Left panels, representative photos of the results. Right panel, quantification of results. Each column indicates the mean ± SD from results of three different experiments. **, P<0.01; ***, P<0.001. (E) Stat3 regulates breast cancer cell brain metastasis by affecting interaction between tumor cells and endothelial cells and tumor cell invasive. Activated Stat3 in tumor cells upregulates the expression of VEGF that induces the phosphorylation of VEGFR2 in endothelial cells. The phosphorylated VEGFR2 leads to phosphorylation hence activation of Stat3 in endothelial cells. Then the activated Stat3 directly upregulates VEGFR2 expression in endothelial cells, which leads to further activation of VEGFR2 in the cells, increasing their infiltration and angiogenesis. Therefore, Stat3 activation orchestrates the interaction between endothelial and tumor cells. Stat3 also directly regulates MMP-9 expression hence breast cancer cell and endothelial invasion. WP1066 can effectively inhibit tumor angiogenesis and invasion thus brain metastasis mediated by Stat3.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496337&req=5

Figure 6: WP1066 inhibits the invasion and migration ability of bEnd.3 cells(A) Cytotoxicity of WP1066 in bEnd.3 cells by MTT assay. bEnd.3 cells were treated with various concentrations of WP1066 or with DMSO for 72 hours. Values are means ± SD for triplicate experiments. *, P<0.1; #, P<0.001. (B) bEnd.3 cells were treated with vehicle or WP1066 1 μM in CM of MDA-MB-231BR cells. Protein expression of VEGFR-2, pVEGFR-2, and β-actin was analyzed by immunoblotting. (C) bEnd.3 cells were cultured with serum-free medium or CM from MDA-MB-231BR cells treated with vehicle or WP1066 1 μM. Then migration ability was determined using the migration assay at 12 hours. Left panels, representative photos of the results. Right panel, quantification of results. Each column indicates the mean ± SD from results of three different experiments. **, P<0.01; ***, P<0.001. (D) bEnd.3 cells were cultured medium as described in (C). Then invasiveness was determined using the invasion assay at 16 hours. Left panels, representative photos of the results. Right panel, quantification of results. Each column indicates the mean ± SD from results of three different experiments. **, P<0.01; ***, P<0.001. (E) Stat3 regulates breast cancer cell brain metastasis by affecting interaction between tumor cells and endothelial cells and tumor cell invasive. Activated Stat3 in tumor cells upregulates the expression of VEGF that induces the phosphorylation of VEGFR2 in endothelial cells. The phosphorylated VEGFR2 leads to phosphorylation hence activation of Stat3 in endothelial cells. Then the activated Stat3 directly upregulates VEGFR2 expression in endothelial cells, which leads to further activation of VEGFR2 in the cells, increasing their infiltration and angiogenesis. Therefore, Stat3 activation orchestrates the interaction between endothelial and tumor cells. Stat3 also directly regulates MMP-9 expression hence breast cancer cell and endothelial invasion. WP1066 can effectively inhibit tumor angiogenesis and invasion thus brain metastasis mediated by Stat3.
Mentions: The above results indicated that Stat3 activity regulated VEGFR-2 in brain endothelial cells and hence regulated their activation, thus, we examined whether WP1066 has direct cytotoxic effects on brain endothelial cells. WP1066 at low concentrations (1-3 μM) was not cytotoxic to bEnd.3 cells (Fig. 6A). However, a low concentration of WP1066 (1 μM) inhibited the activation of brain endothelial cells induced by brain metastatic breast cancer cells (Fig. 6B).

Bottom Line: WP1066 inhibited Stat3 activation in tumor-associated endothelial cells, reducing their infiltration and angiogenesis.WP1066 also inhibited breast cancer cell invasion.Our results indicate that WP1066 can inhibit tumor angiogenesis and brain metastasis mediated by Stat3 in endothelial and tumor cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.

ABSTRACT
Brain metastasis is a major cause of morbidity and mortality in patients with breast cancer. Our previous studies indicated that Stat3 plays an important role in brain metastasis. Here, we present evidence that Stat3 functions at the level of the microenvironment of brain metastases. Stat3 controlled constitutive and inducible VEGFR2 expression in tumor-associated brain endothelial cells. Furthermore, inhibition of Stat3 by WP1066 decreased the incidence of brain metastases and increased survival in a preclinical model of breast cancer brain metastasis. WP1066 inhibited Stat3 activation in tumor-associated endothelial cells, reducing their infiltration and angiogenesis. WP1066 also inhibited breast cancer cell invasion. Our results indicate that WP1066 can inhibit tumor angiogenesis and brain metastasis mediated by Stat3 in endothelial and tumor cells.

No MeSH data available.


Related in: MedlinePlus