Endoglin is a transforming growth factor-beta coreceptor with a crucial role in angiogenesis. A soluble form of endoglin is present in the circulation, but the role of soluble endoglin (sEndoglin)... Show moreEndoglin is a transforming growth factor-beta coreceptor with a crucial role in angiogenesis. A soluble form of endoglin is present in the circulation, but the role of soluble endoglin (sEndoglin) is poorly understood. In addition, the endoglin shedding mechanism is not known. Therefore, we examined the role of sEndoglin in tumor angiogenesis and the mechanism by which the extracellular domain of endoglin is released from the membrane. In colorectal cancer specimens, we observed high endothelial endoglin protein expression, accompanied with slightly lower sEndoglin levels in the circulation, compared with healthy controls. In vitro analysis using endothelial sprouting assays revealed that sEndoglin reduced spontaneous and vascular endothelial growth factor-induced endothelial sprouting. Human umbilical vascular endothelial cells were found to secrete high levels of sEndoglin. Endoglin shedding was inhibited by matrix metalloproteinase (MMP) inhibitors and MMP-14 short hairpin RNA, indicating MMP-14 as the major endoglin shedding protease. Coexpression of endoglin and membrane-bound MMP-14 led to a strong increase in sEndoglin levels. Endoglin shedding required a direct interaction between endoglin and membrane-localized MMP-14. Using cleavage site mutants, we determined that MMP-14 cleaved endoglin at a site in close proximity to the transmembrane domain. Taken together, this study shows that MMP-14 mediates endoglin shedding, which may regulate the angiogenic potential of endothelial cells in the (colorectal) tumor microenvironment. Cancer Res; 70(10); 4141-50. (C) 2010 AACR. Show less
Graauw, M. de; Miltenburg, M.H. van; Schmidt, M.K.; Pont, C.; Lalai, R.; Kartopawiro, J.; ... ; Water, B. van de 2010
Annexin A1 (AnxA1) is a candidate regulator of the epithelial-to mesenchymal (EMT)-like phenotypic switch, a pivotal event in breast cancer progression. We show here that AnxA1 expression is... Show moreAnnexin A1 (AnxA1) is a candidate regulator of the epithelial-to mesenchymal (EMT)-like phenotypic switch, a pivotal event in breast cancer progression. We show here that AnxA1 expression is associated with ahighly invasivebasal- likebreast cancer subtypeboth in apanel of human breast cancer cell lines as in breast cancer patients and that AnxA1 is functionally related to breast cancer progression. AnxA1 knockdownininvasivebasal- likebreast cancer cells reduced the number of spontaneous lung metastasis, whereas additional expression of AnxA1 enhanced metastatic spread. AnxA1 promotes metastasis formation by enhancingTGF beta/Smad signalingandactin reorganization, which facilitates an EMT-like switch, thereby allowing ef. cient cell migration and invasion of metastatic breast cancer cells. Show less
Petersen, M.; Pardali, E.; Horst, G. van der; Cheung, H.; Hoogen, C. van den; Pluijm, G. van der; Dijke, P. ten 2010
Transforming growth factor (TGF)-beta can suppress and promote breast cancer progression. How TGF-beta elicits these dichotomous functions and which roles the principle intracellular effector... Show moreTransforming growth factor (TGF)-beta can suppress and promote breast cancer progression. How TGF-beta elicits these dichotomous functions and which roles the principle intracellular effector proteins Smad2 and Smad3 have therein, is unclear. Here, we investigated the specific functions of Smad2 and Smad3 in TGF-beta-induced responses in breast cancer cells in vitro and in a mouse model for breast cancer metastasis. We stably knocked down Smad2 or Smad3 expression in MDA-MB-231 breast cancer cells. The TGF-beta-induced Smad3-mediated transcriptional response was mitigated and enhanced by Smad3 and Smad2 knockdown, respectively. This response was also seen for TGF-beta-induced vascular endothelial growth factor (VEGF) expression. TGF-beta induction of key target genes involved in bone metastasis, were found to be dependent on Smad3 but not Smad2. Strikingly, whereas knockdown of Smad3 in MDA-MB-231 resulted in prolonged latency and delayed growth of bone metastasis, Smad2 knockdown resulted in a more aggressive phenotype compared with control MDA-MB-231 cells. Consistent with differential effects of Smad knockdown on TGF-beta-induced VEGF expression, these opposing effects of Smad2 versus Smad3 could be directly correlated with divergence in the regulation of tumor angiogenesis in vivo. Thus, Smad2 and Smad3 differentially affect breast cancer bone metastasis formation in vivo. Show less
Petersen, M.; Pardali, E.; Horst, G. van der; Cheung, H.; Hoogen, C. van den; Pluijm, G. van der; Dijke, P. ten 2010
Transforming growth factor (TGF)-beta can suppress and promote breast cancer progression. How TGF-beta elicits these dichotomous functions and which roles the principle intracellular effector... Show moreTransforming growth factor (TGF)-beta can suppress and promote breast cancer progression. How TGF-beta elicits these dichotomous functions and which roles the principle intracellular effector proteins Smad2 and Smad3 have therein, is unclear. Here, we investigated the specific functions of Smad2 and Smad3 in TGF-beta-induced responses in breast cancer cells in vitro and in a mouse model for breast cancer metastasis. We stably knocked down Smad2 or Smad3 expression in MDA-MB-231 breast cancer cells. The TGF-beta-induced Smad3-mediated transcriptional response was mitigated and enhanced by Smad3 and Smad2 knockdown, respectively. This response was also seen for TGF-beta-induced vascular endothelial growth factor (VEGF) expression. TGF-beta induction of key target genes involved in bone metastasis, were found to be dependent on Smad3 but not Smad2. Strikingly, whereas knockdown of Smad3 in MDA-MB-231 resulted in prolonged latency and delayed growth of bone metastasis, Smad2 knockdown resulted in a more aggressive phenotype compared with control MDA-MB-231 cells. Consistent with differential effects of Smad knockdown on TGF-beta-induced VEGF expression, these opposing effects of Smad2 versus Smad3 could be directly correlated with divergence in the regulation of tumor angiogenesis in vivo. Thus, Smad2 and Smad3 differentially affect breast cancer bone metastasis formation in vivo. Oncogene (2010) 29, 1351-1361; doi:10.1038/onc.2009.426; published online 14 December 2009 Show less
Cunha, S.I.; Pardali, E.; Thorikay, M.; Anderberg, C.; Hawinkels, L.; Goumans, M.J.; ... ; Pietras, K. 2010
Members of the transforming growth factor beta (TGF-beta) family have been genetically linked to vascular formation during embryogenesis. However, contradictory studies about the role of TGF-beta... Show moreMembers of the transforming growth factor beta (TGF-beta) family have been genetically linked to vascular formation during embryogenesis. However, contradictory studies about the role of TGF-beta and other family members with reported vascular functions, such as bone morphogenetic protein (BMP) 9, in physiological and pathological angiogenesis make the need for mechanistic studies apparent. We demonstrate, by genetic and pharmacological means, that the TGF-beta and BMP9 receptor activin receptor-like kinase (ALK) 1 represents a new therapeutic target for tumor angiogenesis. Diminution of ALK1 gene dosage or systemic treatment with the ALK1-F-c fusion protein RAP-041 retarded tumor growth and progression by inhibition of angiogenesis in a transgenic mouse model of multistep tumorigenesis. Furthermore, RAP-041 significantly impaired the in vitro and in vivo angiogenic response toward vascular endothelial growth factor A and basic fibroblast growth factor. In seeking the mechanism for the observed effects, we uncovered an unexpected signaling synergy between TGF-beta and BMP9, through which the combined action of the two factors augmented the endothelial cell response to angiogenic stimuli. We delineate a decisive role for signaling by TGF-beta family members in tumor angiogenesis and offer mechanistic insight for the forthcoming clinical development of drugs blocking ALK1 in oncology. Show less
Graauw, M. de; Miltenburg, M.H. van; Schmidt, M.K.; Pont, C.M.; Lalai, R.A.; Kartopawiro, J.; ... ; Water, B. van de 2010
