| 1. |
- Baan, Bart, et al.
(författare)
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In situ proximity ligation detection of c-Jun/AP-1 dimers reveals increased levels of c-Jun/Fra1 complexes in aggressive breast cancer cell lines in vitro and in vivo
- 2010
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 9:9, s. 1982-1990
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Tidskriftsartikel (refereegranskat)abstract
- Genetic and biochemical studies have shown that selective interactions between the Jun, Fos, and activating transcription factor (ATF) components of transcription factor activating protein 1 (AP-1) exhibit specific and critical functions in the regulation of cell proliferation, differentiation, and survival. For instance, the ratio between c-Jun/c-Fos and c-Jun/ATF2 dimers in the cell can be a determining factor in the cellular response to oncogenic or apoptotic stimuli. Until recently, no methods were available to detect endogenous AP-1 complexes in cells and tissues in situ. Here, we validated the proximity ligation assay (PLA) for its ability to specifically visualize and quantify changes in endogenous c-Jun/c-Fos, c-Jun/ATF2, and c-Jun/Fra1 complexes by using, among others, partner-selective c-Jun mutants. Furthermore, we examined the levels of c-Jun/AP-1 dimers in cell lines representing different types of human breast cancer and found that aggressive basal-like breast cancer cells can be discriminated from much less invasive luminal-like cells by PLA detection of c-Jun/Fra1 rather than of c-Jun/ATF2 and c-Jun/c-Fos. Also in tumor tissue derived from highly metastatic basal-like MDA-MB231 cells, high levels of c-Jun/Fra1 complexes were detected. Together, these results demonstrate that in situ PLA is a powerful diagnostic tool to analyze and quantify the amounts of biologically critical AP-1 dimers in fixed cells and tissue material.
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| 2. |
- Cunha, Sara I, et al.
(författare)
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Genetic and pharmacological targeting of activin receptor-like kinase 1 impairs tumor growth and angiogenesis
- 2010
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Ingår i: Journal of Experimental Medicine. - : The Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 207:1, s. 85-100
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Tidskriftsartikel (refereegranskat)abstract
- 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 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.
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| 3. |
- De Boeck, Miriam, et al.
(författare)
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Key role for ubiquitin protein modification in TGFβ signal transduction
- 2012
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Ingår i: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 117:2, s. 153-165
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Forskningsöversikt (refereegranskat)abstract
- The transforming growth factor β (TGFβ) superfamily of signal transduction molecules plays crucial roles in the regulation of cell behavior. TGFβ regulates gene transcription through Smad proteins and signals via non-Smad pathways. The TGFβ pathway is strictly regulated, and perturbations lead to tumorigenesis. Several pathway components are known to be targeted for proteasomal degradation via ubiquitination by E3 ligases. Smurfs are well known negative regulators of TGFβ, which function as E3 ligases recruited by adaptors such as I-Smads. TGFβ signaling can also be enhanced by E3 ligases, such as Arkadia, that target repressors for degradation. It is becoming clear that E3 ligases often target multiple pathways, thereby acting as mediators of signaling cross-talk. Regulation via ubiquitination involves a complex network of E3 ligases, adaptor proteins, and deubiquitinating enzymes (DUBs), the last-mentioned acting by removing ubiquitin from its targets. Interestingly, also non-degradative ubiquitin modifications are known to play important roles in TGFβ signaling. Ubiquitin modifications thus play a key role in TGFβ signal transduction, and in this review we provide an overview of known players, focusing on recent advances.
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| 4. |
- de Kruijf, E M, et al.
(författare)
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The prognostic role of TGF-β signaling pathway in breast cancer patients
- 2013
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Ingår i: Annals of Oncology. - : Elsevier BV. - 0923-7534 .- 1569-8041. ; 24:2, s. 384-390
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe transforming growth factor-β (TGF-β) pathway has dual effects on tumor growth. Seemingly, discordant results have been published on the relation between TGF-β signaling markers and prognosis in breast cancer. Improved prognostic information for breast cancer patients might be obtained by assessing interactions among TGF-β signaling biomarkers.Patients and methodsThe expression of nuclear Smad4, nuclear phosphorylated-Smad2 (p-Smad2), and the membranous expression of TGF-β receptors I and II (TβRI and TβRII) was determined on a tissue microarray of 574 breast carcinomas. Tumors were stratified according to the Smad4 expression in combination with p-Smad2 expression or Smad4 in combination with the expression of both TGF-β receptors.ResultsTumors with high expression of TβRII, TβRI and TβRII, and p-Smad2 (P = 0.018, 0.005, and 0.022, respectively), and low expression of Smad4 (P = 0.005) had an unfavorable prognosis concerning progression-free survival. Low Smad4 expression combined with high p-Smad2 expression or low expression of Smad4 combined with high expression of both TGF-β receptors displayed an increased hazard ratio of 3.04 [95% confidence interval (CI) 1.390-6.658] and 2.20 (95% CI 1.464-3.307), respectively, for disease relapse.ConclusionsCombining TGF-β biomarkers provides prognostic information for patients with stage I-III breast cancer. This can identify patients at increased risk for disease recurrence that might therefore be candidates for additional treatment.
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| 5. |
- Drabsch, Yvette, et al.
(författare)
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TGF-beta Signaling in Breast Cancer Cell Invasion and Bone Metastasis
- 2011
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Ingår i: Journal of mammary gland biology and neoplasia. - : Springer. - 1083-3021 .- 1573-7039. ; 16:2, s. 97-108
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Tidskriftsartikel (refereegranskat)abstract
- The contribution of transforming growth factor beta (TGF-beta) signaling to breast cancer has been studied for more than two decades. In an early phase TGF-beta may act as a tumour suppressor, while later, when cells have become resistant to its anti-mitogenic effects, the role of TGF-beta switches towards malignant conversion and progression. TGF-beta stimulates cell invasion and modifies the microenvironment to the advantage of cancer cells. Studies have shown that TGF-beta promotes bone and lung metastasis via different mechanisms. The therapeutic strategies to target the TGF-beta pathway in breast cancer are becoming increasingly clear. This review will focus on the role TGF-beta in breast cancer invasion and metastasis.
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| 6. |
- Drabsch, Yvette, et al.
(författare)
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TGF-β signalling and its role in cancer progression and metastasis
- 2012
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Ingår i: Cancer Metastasis Review. - : Springer Science and Business Media LLC. - 0167-7659 .- 1573-7233. ; 31:3-4, s. 553-568
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Forskningsöversikt (refereegranskat)abstract
- The transforming growth factor-β (TGF-β) system signals via protein kinase receptors and SMAD mediators to regulate a large number of biological processes. Alterations of the TGF-β signalling pathway are implicated in human cancer. Prior to tumour initiation and early during progression, TGF-β acts as a tumour suppressor; however, at later stages, it is often a tumour promoter. Knowledge about the mechanisms involved in TGF-β signal transduction has allowed a better understanding of cancer progression, invasion, metastasis and epithelial-to-mesenchymal transition. Furthermore, several molecular targets with great potential in therapeutic interventions have been identified. This review discusses the TGF-β signalling pathway, its involvement in cancer and current therapeutic approaches.
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| 7. |
- Drabsch, Yvette, et al.
(författare)
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Transforming growth factor-β signalling controls human breast cancer metastasis in a zebrafish xenograft model
- 2013
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Ingår i: Breast Cancer Research. - : Springer Science and Business Media LLC. - 1465-5411 .- 1465-542X. ; 15:6, s. R106-
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The transforming growth factor beta (TGF-β) signalling pathway is known to control human breast cancer invasion and metastasis. We demonstrate that the zebrafish xenograft assay is a robust and dependable animal model for examining the role of pharmacological modulators and genetic perturbation of TGF-β signalling in human breast tumour cells.METHODS: We injected cancer cells into the embryonic circulation (duct of cuvier) and examined their invasion and metastasis into the avascular collagenous tail. Various aspects of the TGF-β signalling pathway were blocked by chemical inhibition, small interfering RNA (siRNA), or small hairpin RNA (shRNA). Analysis was conducted using fluorescent microscopy.RESULTS: Breast cancer cells with different levels of malignancy, according to in vitro and in vivo mouse studies, demonstrated invasive and metastatic properties within the embryonic zebrafish model that nicely correlated with their differential tumourigenicity in mouse models. Interestingly, MCF10A M2 and M4 cells invaded into the caudal hematopoietic tissue and were visible as a cluster of cells, whereas MDA MB 231 cells invaded into the tail fin and were visible as individual cells. Pharmacological inhibition with TGF-β receptor kinase inhibitors or tumour specific Smad4 knockdown disturbed invasion and metastasis in the zebrafish xenograft model and closely mimicked the results we obtained with these cells in a mouse metastasis model. Inhibition of matrix metallo proteinases, which are induced by TGF-β in breast cancer cells, blocked invasion and metastasis of breast cancer cells.CONCLUSIONS: The zebrafish-embryonic breast cancer xenograft model is applicable for the mechanistic understanding, screening and development of anti-TGF-β drugs for the treatment of metastatic breast cancer in a timely and cost-effective manner.
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| 8. |
- Hawinkels, Lukas J A C, et al.
(författare)
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Exploring anti-TGF-β therapies in cancer and fibrosis
- 2011
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Ingår i: Growth Factors. - : Informa UK Limited. - 0897-7194 .- 1029-2292. ; 29:4, s. 140-152
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor-β (TGF-β) is a multifunctional cytokine, with important roles in maintaining tissue homeostasis. TGF-β signals via transmembrane serine/threonine kinase receptors and intracellular Smad transcriptional regulators. Perturbed TGF-β signaling has been implicated in a large variety of pathological conditions. Increased TGF-β levels have been found in patients with cancer, fibrosis, and systemic sclerosis, and were correlated with disease severity. In cancer, TGF-β mediates tumor invasion and metastasis by affecting both tumor cells and the tumor microenvironment including fibroblast activation and immune suppression. Furthermore, TGF-β is a strong stimulator of extracellular matrix deposition. On the basis of these observations, small molecule inhibitors of the TGF-β receptor kinases, neutralizing antibodies that interfere with ligand?receptor interactions, antisense oligonucleotides reducing TGF-β expression, and soluble receptor ectodomains that sequester TGF-β have been developed to intervene with excessive TGF-β signaling activity in the aforementioned disorders. Here, we review the current state of anti-TGF-β therapy in clinical trials.
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| 10. |
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