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Death receptor 6 (DR6) is required for mouse B16 tumor angiogenesis via the NF-κB, P38 MAPK and STAT3 pathways.

Yang X, Shi B, Li L, Xu Z, Ge Y, Shi J, Liu Y, Zheng D - Oncogenesis (2016)

Bottom Line: Although death receptor 6 (DR6) is aberrantly expressed in certain cancer cell lines, its function, signaling pathway and potential clinical significance in tumor progression are not well characterized.Deficiency of DR6 changes cytokine expression and secretion; in particular, it inhibits the proinflammatory cytokine interleukin-6 (IL-6), which is able to induce the expression of the angiogenesis-related factors: vascular endothelial growth factor-A, platelet-derived growth factor-β, vascular endothelial growth factor-D and platelet-derived growth factor receptor-α.Further experiments demonstrate that DR6-dependent angiogenesis is involved in the IL-6/P38 MAPK and IL-6/STAT3 pathways.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

ABSTRACT
Although death receptor 6 (DR6) is aberrantly expressed in certain cancer cell lines, its function, signaling pathway and potential clinical significance in tumor progression are not well characterized. We report here that knocking down DR6 in the mouse B16 cell line has no effect on B16 cell death in vitro but suppresses xenograft B16 tumor growth by preventing tumor blood vessel formation in vivo. Deficiency of DR6 changes cytokine expression and secretion; in particular, it inhibits the proinflammatory cytokine interleukin-6 (IL-6), which is able to induce the expression of the angiogenesis-related factors: vascular endothelial growth factor-A, platelet-derived growth factor-β, vascular endothelial growth factor-D and platelet-derived growth factor receptor-α. Further experiments demonstrate that DR6-dependent angiogenesis is involved in the IL-6/P38 MAPK and IL-6/STAT3 pathways. Our novel findings demonstrate for the first time that DR6 expression in B16 cells facilitates tumor growth by accelerating tumor angiogenesis. Moreover, these results suggest that DR6 is involved in three important intracellular pathways that lead to homeostatic angiogenesis in tumor growth.

No MeSH data available.


Related in: MedlinePlus

DR6 mediates tumor angiogenesis via IL-6. (a) Secreted IL-6 protein levels in cultivated media from B16 cells measured by ELISA. (b) VEGF-D and PDGFR-α protein in B16 cells were tested by rescue experiment. (c) VEGF-A protein in the cultured media of B16 cells was evaluated by ELISA assays. For (b) and (c), B16 cells were transfected with siDR6 or control (siNC) for 48 h and then treated with IL-6 for 12 h. The error bars represent the standard deviation of the mean values obtained from triplicate experiments. P<0.05 is considered to be statistically significant. (d) DR6 expression in B16 cells. B16 cells were treated with exogenous IL-6 (40 ng/ml) for 0–12 h and then were subjected to western blot assays. GAPDH was used as the loading control.
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fig4: DR6 mediates tumor angiogenesis via IL-6. (a) Secreted IL-6 protein levels in cultivated media from B16 cells measured by ELISA. (b) VEGF-D and PDGFR-α protein in B16 cells were tested by rescue experiment. (c) VEGF-A protein in the cultured media of B16 cells was evaluated by ELISA assays. For (b) and (c), B16 cells were transfected with siDR6 or control (siNC) for 48 h and then treated with IL-6 for 12 h. The error bars represent the standard deviation of the mean values obtained from triplicate experiments. P<0.05 is considered to be statistically significant. (d) DR6 expression in B16 cells. B16 cells were treated with exogenous IL-6 (40 ng/ml) for 0–12 h and then were subjected to western blot assays. GAPDH was used as the loading control.

Mentions: Knocking down DR6 of B16 cells decreased IL-6 mRNA (Figure 3c), and secreted IL-6 in B16 cells cultured media was dramatically downregulated in DR6 deficient (siDR6), compared with control (siNC) (Figure 4a), suggesting that IL-6 is involved in DR6 signaling. IL-6 signaling has been reported to play an important role in VEGF-A-dependent tumor angiogenesis.8, 13 Therefore, we next examined its role in DR6-mediated mouse B16 tumor angiogenesis. In B16 cells, VEGF-A, VEGF-D, PDGF-β and PDGFR-α were upregulated by IL-6 treatment on a concentration- or a time-dependent manner (Supplementary Figure S6). Not surprisingly, as shown in Figures 4b and c, the VEGF-D and PDGFR-α protein in B16 cells and the secreted VEGF-A in the cell media from DR6-deficient B16 cells were rescued by the treatment with IL-6.


Death receptor 6 (DR6) is required for mouse B16 tumor angiogenesis via the NF-κB, P38 MAPK and STAT3 pathways.

Yang X, Shi B, Li L, Xu Z, Ge Y, Shi J, Liu Y, Zheng D - Oncogenesis (2016)

DR6 mediates tumor angiogenesis via IL-6. (a) Secreted IL-6 protein levels in cultivated media from B16 cells measured by ELISA. (b) VEGF-D and PDGFR-α protein in B16 cells were tested by rescue experiment. (c) VEGF-A protein in the cultured media of B16 cells was evaluated by ELISA assays. For (b) and (c), B16 cells were transfected with siDR6 or control (siNC) for 48 h and then treated with IL-6 for 12 h. The error bars represent the standard deviation of the mean values obtained from triplicate experiments. P<0.05 is considered to be statistically significant. (d) DR6 expression in B16 cells. B16 cells were treated with exogenous IL-6 (40 ng/ml) for 0–12 h and then were subjected to western blot assays. GAPDH was used as the loading control.
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Related In: Results  -  Collection

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fig4: DR6 mediates tumor angiogenesis via IL-6. (a) Secreted IL-6 protein levels in cultivated media from B16 cells measured by ELISA. (b) VEGF-D and PDGFR-α protein in B16 cells were tested by rescue experiment. (c) VEGF-A protein in the cultured media of B16 cells was evaluated by ELISA assays. For (b) and (c), B16 cells were transfected with siDR6 or control (siNC) for 48 h and then treated with IL-6 for 12 h. The error bars represent the standard deviation of the mean values obtained from triplicate experiments. P<0.05 is considered to be statistically significant. (d) DR6 expression in B16 cells. B16 cells were treated with exogenous IL-6 (40 ng/ml) for 0–12 h and then were subjected to western blot assays. GAPDH was used as the loading control.
Mentions: Knocking down DR6 of B16 cells decreased IL-6 mRNA (Figure 3c), and secreted IL-6 in B16 cells cultured media was dramatically downregulated in DR6 deficient (siDR6), compared with control (siNC) (Figure 4a), suggesting that IL-6 is involved in DR6 signaling. IL-6 signaling has been reported to play an important role in VEGF-A-dependent tumor angiogenesis.8, 13 Therefore, we next examined its role in DR6-mediated mouse B16 tumor angiogenesis. In B16 cells, VEGF-A, VEGF-D, PDGF-β and PDGFR-α were upregulated by IL-6 treatment on a concentration- or a time-dependent manner (Supplementary Figure S6). Not surprisingly, as shown in Figures 4b and c, the VEGF-D and PDGFR-α protein in B16 cells and the secreted VEGF-A in the cell media from DR6-deficient B16 cells were rescued by the treatment with IL-6.

Bottom Line: Although death receptor 6 (DR6) is aberrantly expressed in certain cancer cell lines, its function, signaling pathway and potential clinical significance in tumor progression are not well characterized.Deficiency of DR6 changes cytokine expression and secretion; in particular, it inhibits the proinflammatory cytokine interleukin-6 (IL-6), which is able to induce the expression of the angiogenesis-related factors: vascular endothelial growth factor-A, platelet-derived growth factor-β, vascular endothelial growth factor-D and platelet-derived growth factor receptor-α.Further experiments demonstrate that DR6-dependent angiogenesis is involved in the IL-6/P38 MAPK and IL-6/STAT3 pathways.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

ABSTRACT
Although death receptor 6 (DR6) is aberrantly expressed in certain cancer cell lines, its function, signaling pathway and potential clinical significance in tumor progression are not well characterized. We report here that knocking down DR6 in the mouse B16 cell line has no effect on B16 cell death in vitro but suppresses xenograft B16 tumor growth by preventing tumor blood vessel formation in vivo. Deficiency of DR6 changes cytokine expression and secretion; in particular, it inhibits the proinflammatory cytokine interleukin-6 (IL-6), which is able to induce the expression of the angiogenesis-related factors: vascular endothelial growth factor-A, platelet-derived growth factor-β, vascular endothelial growth factor-D and platelet-derived growth factor receptor-α. Further experiments demonstrate that DR6-dependent angiogenesis is involved in the IL-6/P38 MAPK and IL-6/STAT3 pathways. Our novel findings demonstrate for the first time that DR6 expression in B16 cells facilitates tumor growth by accelerating tumor angiogenesis. Moreover, these results suggest that DR6 is involved in three important intracellular pathways that lead to homeostatic angiogenesis in tumor growth.

No MeSH data available.


Related in: MedlinePlus