| 1. |
- Aripaka, Karthik, et al.
(författare)
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TRAF6 function as a novel co-regulator of Wnt3a target genes in prostate cancer
- 2019
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Ingår i: EBioMedicine. - : Elsevier. - 2352-3964. ; 45, s. 192-207
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Tidskriftsartikel (refereegranskat)abstract
- Background: Tumour necrosis factor receptor associated factor 6 (TRAF6) promotes inflammation in response to various cytokines. Aberrant Wnt3a signals promotes cancer progression through accumulation of β-Catenin. Here we investigated a potential role for TRAF6 in Wnt signaling.Methods: TRAF6 expression was silenced by siRNA in human prostate cancer (PC3U) and human colorectal SW480 cells and by CRISPR/Cas9 in zebrafish. Several biochemical methods and analyses of mutant phenotype in zebrafish were used to analyse the function of TRAF6 in Wnt signaling.Findings: Wnt3a-treatment promoted binding of TRAF6 to the Wnt co-receptors LRP5/LRP6 in PC3U and LNCaP cells in vitro. TRAF6 positively regulated mRNA expression of β-Catenin and subsequent activation of Wnt target genes in PC3U cells. Wnt3a-induced invasion of PC3U and SW480 cells were significantly reduced when TRAF6 was silenced by siRNA. Database analysis revealed a correlation between TRAF6 mRNA and Wnt target genes in patients with prostate cancer, and high expression of LRP5, TRAF6 and c-Myc correlated with poor prognosis. By using CRISPR/Cas9 to silence TRAF6 in zebrafish, we confirm TRAF6 as a key molecule in Wnt3a signaling for expression of Wnt target genes.Interpretation: We identify TRAF6 as an important component in Wnt3a signaling to promote activation of Wnt target genes, a finding important for understanding mechanisms driving prostate cancer progression.
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| 2. |
- Christoffersson, Gustav, et al.
(författare)
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Vascular adaptation to a dysfunctional endothelium as a consequence of Shb deficiency
- 2012
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Ingår i: Angiogenesis. - : Springer Science and Business Media LLC. - 0969-6970 .- 1573-7209. ; 15:3, s. 469-480
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Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial growth factor (VEGF)-A regulates angiogenesis, vascular morphology and permeability by signaling through its receptor VEGFR-2. The Shb adapter protein has previously been found to relay certain VEGFR-2 dependent signals and consequently vascular physiology and structure was assessed in Shb knockout mice. X-ray computed tomography of vessels larger than 24 mm diameter (micro-CT) after contrast injection revealed an increased frequency of 48-96 µm arterioles in the hindlimb calf muscle in Shb knockout mice. Intravital microscopy of the cremaster muscle demonstrated a less regular vasculature with fewer branch points and increased vessel tortuosity, changes that led to an increased blood flow velocity. Reduced in vivo angiogenesis was observed in Shb knockout MatrigelTM plugs. Unlike the wild-type situation, VEGF-A did not provoke a dissociation of VE-cadherin from adherens junctions in Shb knockout venules. The reduced angiogenesis and altered properties of junctions had consequences for two patho-physiological responses to arterial occlusion: vascular permeability was reduced in the Shb knockout cremaster muscle after ligation of one supplying artery and heat-induced blood flow determined by Laser-Doppler measurements was decreased in the hindlimb after ligation of the femoral artery. Consequently, the Shb knockout mouse exhibited structural and functional (angiogenesis and vascular permeability) vascular abnormalities that have implications for understanding the function of VEGF-A under physiological conditions.
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| 3. |
- Funa, Nina S, et al.
(författare)
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Dysfunctional microvasculature as a consequence of shb gene inactivation causes impaired tumor growth
- 2009
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 69:5, s. 2141-2148
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Tidskriftsartikel (refereegranskat)abstract
- Shb (Src homology 2 protein B) is an adapter protein downstream of the vascular endothelial growth factor receptor receptor-2 (VEGFR-2). Previous experiments have suggested a role for Shb in endothelial cell function. Recently, the Shb gene was inactivated and Shb null mice were obtained on a mixed genetic background, but not on C57Bl6 mice. The present study was performed to address endothelial function in the Shb knockout mouse and its relevance for tumor angiogenesis. Tumor growth was retarded in Shb mutant mice, and this correlated with decreased angiogenesis both in tumors and in Matrigel plugs. Shb null mice display an abnormal endothelial ultrastructure in liver sinusoids and heart capillaries with cytoplasmic extensions projecting toward the lumen. Shb null heart VE-cadherin staining was less distinct than that of control heart, exhibiting in the former case a wavy and punctuate pattern. Experiments on isolated endothelial cells suggest that these changes could partly reflect cytoskeletal abnormalities. Vascular permeability was increased in Shb null mice in heart, kidney, and skin, whereas VEGF-stimulated vascular permeability was reduced in Shb null mice. It is concluded that Shb plays an important role in maintaining a functional vasculature in adult mice, and that interference with Shb signaling may provide novel means to regulate tumor angiogenesis.
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| 4. |
- Gudey, Shyam Kumar, et al.
(författare)
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TRAF6 stimulates the tumor-promoting effects of TGF beta type I receptor through polyubiquitination and activation of Presenilin 1
- 2014
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Ingår i: Science Signaling. - : American Association for the Advancement of Science. - 1945-0877 .- 1937-9145. ; 7:307
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor-beta (TGF beta) can be both a tumor promoter and suppressor, although the mechanisms behind the protumorigenic switch remain to be fully elucidated. The TGF beta type I receptor (T beta RI) is proteolytically cleaved in the ectodomain region. Cleavage requires the combined activities of tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) and TNF-alpha-converting enzyme (TACE). The cleavage event occurs selectively in cancer cells and generates an intracellular domain (ICD) of T beta RI, which enters the nucleus to mediate gene transcription. Presenilin 1 (PS1), a gamma-secretase catalytic core component, mediates intramembrane proteolysis of transmembrane receptors, such as Notch. We showed that TGF beta increased both the abundance and activity of PS1. TRAF6 recruited PS1 to the T beta RI complex and promoted lysine-63-linked polyubiquitination of PS1, which activated PS1. Furthermore, PS1 cleaved T beta RI in the transmembrane domain between valine-129 and isoleucine-130, and ICD generation was inhibited when these residues were mutated to alanine. We also showed that, after entering the nucleus, T beta RI-ICD bound to the promoter and increased the transcription of the gene encoding T beta RI. The TRAF6- and PS1-induced intramembrane proteolysis of T beta RI promoted TGF beta-induced invasion of various cancer cells in vitro. Furthermore, when a mouse xenograft model of prostate cancer was treated with the gamma-secretase inhibitor DBZ {(2S)-2-[2-(3,5-difluorophenyl)-acetylamino]-N-(5-methyl-6-oxo-6,7-dihydro-5H-dibenzo[b, d]azepin-7-yl)-propionamide}, generation of T beta RI-ICD was prevented, transcription of the gene encoding the proinvasive transcription factor Snail1 was reduced, and tumor growth was inhibited. These results suggest that gamma-secretase inhibitors may be useful for treating aggressive prostate cancer.
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| 5. |
- Gudey, Shyam Kumar, et al.
(författare)
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TRAF6 Stimulates the Tumor-Promoting Effects of TGFβ Type I Receptor Through Polyubiquitination and Activation of Presenilin 1
- 2014
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Ingår i: Science signaling. - : American Association for the Advancement of Science (AAAS). - 1937-9145 .- 1945-0877. ; 7:307, s. ra2-
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor-β (TGFβ) can be both a tumor promoter and suppressor, although the mechanisms behind the protumorigenic switch remain to be fully elucidated. The TGFβ type I receptor (TβRI) is proteolytically cleaved in the ectodomain region. Cleavage requires the combined activities of tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) and TNF-α-converting enzyme (TACE). The cleavage event occurs selectively in cancer cells and generates an intracellular domain (ICD) of TβRI, which enters the nucleus to mediate gene transcription. Presenilin 1 (PS1), a γ-secretase catalytic core component, mediates intramembrane proteolysis of transmembrane receptors, such as Notch. We showed that TGFβ increased both the abundance and activity of PS1. TRAF6 recruited PS1 to the TβRI complex and promoted lysine-63-linked polyubiquitination of PS1, which activated PS1. Furthermore, PS1 cleaved TβRI in the transmembrane domain between valine-129 and isoleucine-130, and ICD generation was inhibited when these residues were mutated to alanine. We also showed that, after entering the nucleus, TβRI-ICD bound to the promoter and increased the transcription of the gene encoding TβRI. The TRAF6- and PS1-induced intramembrane proteolysis of TβRI promoted TGFβ-induced invasion of various cancer cells in vitro. Furthermore, when a mouse xenograft model of prostate cancer was treated with the γ-secretase inhibitor DBZ {(2S)-2-[2-(3,5-difluorophenyl)-acetylamino]-N-(5-methyl-6-oxo-6,7-dihydro-5H-dibenzo[b,d]azepin-7-yl)-propionamide}, generation of TβRI-ICD was prevented, transcription of the gene encoding the proinvasive transcription factor Snail1 was reduced, and tumor growth was inhibited. These results suggest that γ-secretase inhibitors may be useful for treating aggressive prostate cancer.
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| 6. |
- Henriksnäs, Johanna, et al.
(författare)
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Markedly Decreased Blood Perfusion of Pancreatic Islets Transplanted Intraportally Into the Liver : Disruption of Islet Integrity Necessary for Islet Revascularization
- 2012
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 61:3, s. 665-673
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Tidskriftsartikel (refereegranskat)abstract
- Experimental studies indicate low revascularization of intraportally transplanted islets. This study aimed to quantify, for the first time, the blood perfusion of intrahepatically transplanted islets and elucidate necessary factors for proper islet graft revascularization at this site. Yellow chameleon protein 3.0 islets expressing fluorescent protein in all cells were transplanted. Graft blood perfusion was determined by microspheres. The vascular density and relative contribution of donor blood vessels in revascularization was evaluated using islets expressing green fluorescent protein under the Tie-2 promoter. Blood perfusion of intrahepatic islets was as a mean only 5% of that of native islets at 1-month posttransplantation. However, there was a marked heterogeneity where blood perfusion was less decreased hi islets transplanted without prior culture and in many cases restored in islets with disrupted integrity. Analysis of vascular density showed that distorted islets were well revascularized, whereas islets still intact at 1-month posttransplantation were almost avascular. Few donor endothelial cells were observed in the new islet vasculature. The very low blood perfusion of intraportally transplanted islets is likely to predispose for ischemia and hamper islet function. Since donor endothelial cells do not expand posttransplantation, disruption of islet integrity is necessary for revascularization to occur by recipient blood vessels.
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| 7. |
- Hui, Zhixuan, et al.
(författare)
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TGFβ-induced EN1 promotes tumor budding of adenoid cystic carcinoma in patient-derived organoid model
- 2024
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Ingår i: International Journal of Cancer. - : John Wiley & Sons. - 0020-7136 .- 1097-0215. ; 154:10, s. 1814-1827
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Tidskriftsartikel (refereegranskat)abstract
- Adenoid cystic carcinoma (ACC) and basal cell adenoma (BCA) share many histological characteristics and often need a differential diagnosis in clinical pathology. Recently, we found homeobox protein engrailed-1 (EN1) was a potential diagnostic marker for ACC in an organoids library of salivary gland tumors (SGTs). Here we aim to confirm EN1 as a differential diagnostic marker for ACC, and further investigate the regulatory mechanism and biological function of EN1 in tumor progression. The transcriptional analysis, quantitative polymerase chain reaction, Western blot and immunohistochemistry staining were performed and revealed that EN1 was specifically and highly expressed in ACC, and accurately differentiated ACC from BCA. Furthermore, TGFβ signaling pathway was found associated with ACC, and the regulation of EN1 through TGFβ was detected in the human ACC cell lines and patient-derived organoids (PDOs). TGFβ-induced EN1 was important in promoting tumor budding in the PDOs model. Interestingly, a high level of EN1 and TGFβ1 in the budding tips was observed in ACC clinical samples, and the expression of EN1 and TGFβ1 in ACC was significantly associated with the clinical stage. In summary, our study verified EN1 is a good diagnostic marker to differentiate ACC from BCA. TGFβ-induced EN1 facilitates the tumor budding of ACC, which might be an important mechanism related to the malignant phenotype of ACC.
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| 8. |
- Mu, Yabing, et al.
(författare)
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TGF beta-induced phosphorylation of Par6 promotes migration and invasion in prostate cancer cells
- 2015
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Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 112:7, s. 1223-1231
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Tidskriftsartikel (refereegranskat)abstract
- Background:The Par complex - comprising partition-defective 6 (Par6), Par3, and atypical protein kinase C (aPKC) - is crucial for cell polarisation, the loss of which contributes to cancer progression. Transforming growth factor beta (TGF beta)-induced phosphorylation of Par6 on the conserved serine 345 is implicated in epithelial-to-mesenchymal transition (EMT) in breast cancer. Here we investigated the importance of phosphorylated Par6 in prostate cancer.Methods:We generated a p-Par6(345)-specific antibody and verified its specificity in vitro. Endogenous p-Par6(345) was analysed by immunoblotting in normal human prostate RWPE1 and prostate cancer (PC-3U) cells. Subcellular localisation of p-Par6(345) in migrating TGF beta-treated PC-3U cells was analysed by confocal imaging. Invasion assays of TGF beta-treated PC-3U cells were performed. p-Par6 expression was immunohistochemically analysed in prostate cancer tissues.Results:TGF beta induced Par6 phosphorylation on Ser345 and its recruitment to the leading edge of the membrane ruffle in migrating PC-3U cells, where it colocalised with aPKC zeta. The p-Par6-aPKC zeta complex is important for cell migration and invasion, as interference with this complex prevented prostate cancer cell invasion. High levels of activated Par6 correlated with aggressive prostate cancer.Conclusions: Increased p-Par6Ser(345) levels in aggressive prostate cancer tissues and cells suggest that it could be a useful novel biomarker for predicting prostate cancer progression.
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| 9. |
- Mu, Yabing, et al.
(författare)
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TGFβ-induced activation of PKCζ confers invasive prostate cancer growth
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- One of the hallmarks for aggressivecancer is the capability oftumor cells to become invasive and metastatic. Cancer cells and tumor stromal cells oftenproduce high levels of transforming growth factor b(TGFb) which initiates intracellular signaling pathways in cancer cells in a contextualdependentmanner. Atypical protein kinase C z(PKCz) is a multifunctional protein which maintains cell polarity of normal epithelial cells, while itsaberrantexpression and activation is linked to tumor progression. Tumor necrosisfactor receptor-associated factor6 (TRAF6) is amplified in lung cancer and caninitiate intracellular oncogenic signals. In prostate cancer cellsTRAF6 promotesligand-induced proteolytic cleavage of TGFbtype I receptor(TbRI), and nuclear translocation of its intracellular domain (ICD) to confer invasion of cancer cells. Here we report our novel findingsthat PKCzharboursa TRAF6 consensus binding site and that TRAF6 causes Lys63-linked polyubiquitination of PKCz. TGFb-induced phosphorylationof PKCzis dependent on TRAF6in prostate cancer cells and we have investigated the potential usefulness of twodifferent inhibitors of PKCzas potential novel anti-cancer drugs.
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| 10. |
- Sun, Zuyue, et al.
(författare)
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VEGFR2 induces c-Src signaling and vascular permeability in vivo via the adaptor protein TSAd
- 2012
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Ingår i: Journal of Experimental Medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 209:7, s. 1363-1377
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Tidskriftsartikel (refereegranskat)abstract
- Regulation of vascular endothelial (VE) growth factor (VEGF)-induced permeability is critical in physiological and pathological processes. We show that tyrosine phosphorylation of VEGF receptor 2 (VEGFR2) at Y951 facilitates binding of VEGFR2 to the Rous sarcoma (Src) homology 2-domain of T cell-specific adaptor (TSAd), which in turn regulates VEGF-induced activation of the c-Src tyrosine kinase and vascular permeability. c-Src was activated in vivo and in vitro in a VEGF/TSAd-dependent manner, and was regulated via increased phosphorylation at pY418 and reduced phosphorylation at pY527. Tsad silencing blocked VEGF-induced c-Src activation, but did not affect pathways involving phospholipase C gamma, extracellular regulated kinase, and endothelial nitric oxide. VEGF-induced rearrangement of VE-cadherin-positive junctions in endothelial cells isolated from mouse lungs, or in mouse cremaster vessels, was dependent on TSAd expression, and TSAd formed a complex with VE-cadherin, VEGFR2, and c-Src at endothelial junctions. Vessels in tsad(-/-) mice showed undisturbed flow and pressure, but impaired VEGF-induced permeability, as measured by extravasation of Evans blue, dextran, and microspheres in the skin and the trachea. Histamine-induced extravasation was not affected by TSAd deficiency. We conclude that TSAd is required for VEGF-induced, c-Src-mediated regulation of endothelial cell junctions and for vascular permeability.
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| 11. |
- Wang, Bo, et al.
(författare)
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An organoid library of salivary gland tumors reveals subtype-specific characteristics and biomarkers
- 2022
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Ingår i: Journal of Experimental & Clinical Cancer Research. - : BioMed Central (BMC). - 1756-9966. ; 41:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Salivary gland tumors (SGTs) include a large group of rare neoplasms in the head and neck region, and the heterogeneous and overlapping features among the subtypes frequently make diagnostic difficulties. There is an urgent need to understand the cellular mechanisms underlying the heterogeneity and overlap among the subtypes, and explore the subtype-specific diagnostic biomarkers.Methods: The tumor tissue and the adjacent normal tissue from the 6 most common types of SGTs were processed for organoid culture which only maintained tumor epithelial cells. Organoids were histologically evaluated based on phenotype markers, followed by transcriptional profiling using RNA-sequencing. The transcriptomic similarities and differences among the subtypes were analyzed by subtype consensus clustering and hierarchical clustering. Furthermore, by comparative transcriptional analysis for these 6 types of SGTs and the matched organoids, the potential diagnostic biomarkers from tumor epithelium were identified, in which two selected biomarkers were evaluated by qPCR and confirmed by immunohistochemistry staining using a tissue microarray.Results: We generated a biobank of patient-derived organoids (PDOs) with 6 subtypes of SGTs, including 21 benign and 24 malignant SGTs. The PDOs recapitulated the morphological and transcriptional characteristics of the parental tumors. The overlap in the cell types and the heterogenous growth patterns were observed in the different subtypes of organoids. Comparing the bulk tissues, the cluster analysis of the PDOs remarkably revealed the epithelial characteristics, and visualized the intrinsic relationship among these subtypes. Finally, the exclusive biomarkers for the 6 most common types of SGTs were uncovered by comparative analysis, and PTP4A1 was demonstrated as a useful diagnostic biomarker for mucoepidermoid carcinoma.Conclusions: We established the first organoid biobank with multiple subtypes of SGTs. PDOs of SGTs recapitulate the morphological and transcriptional characteristics of the original tumors, which uncovers subtype-specific biomarkers and reveals the molecular distance among the subtype of SGTs.
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| 12. |
- Welsh, Michael, et al.
(författare)
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The role of the Src Homology-2 domain containing protein B (SHB) in β cells
- 2015
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Ingår i: Journal of Molecular Endocrinology. - 0952-5041 .- 1479-6813. ; 56:1, s. R21-R31
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Forskningsöversikt (refereegranskat)abstract
- This review will describe the SH2-domain signaling protein Src Homology-2 domaincontaining protein B (SHB) and its role in various physiological processes relating inparticular to glucose homeostasis andbcell function. SHB operates downstream of severaltyrosine kinase receptors and assembles signaling complexes in response to receptoractivation by interacting with other signaling proteins via its other domains (proline-rich,phosphotyrosine-binding and tyrosine-phosphorylation sites). The subsequent responsesare context-dependent. Absence ofShbin mice has been found to exert effects onhematopoiesis, angiogenesis and glucose metabolism. Specifically, first-phase insulinsecretion in response to glucose was impaired and this effect was related to alteredcharacteristics of focal adhesion kinase activation modulating signaling through Akt, ERK,bcatenin and cAMP. It is believed that SHB plays a role in integrating adaptive responses tovarious stimuli by simultaneously modulating cellular responses in different cell-types, thusplaying a role in maintaining physiological homeostasis
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| 13. |
- Yakymovych, Ihor, et al.
(författare)
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CIN85 modulates TGF beta signaling by promoting the presentation of TGF beta receptors on the cell surface
- 2015
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Ingår i: Journal of Cell Biology. - : Rockefeller University Press. - 0021-9525 .- 1540-8140. ; 210:2, s. 319-332
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Tidskriftsartikel (refereegranskat)abstract
- Members of the transforming growth factor beta (TGF beta) family initiate cellular responses by binding to TGF beta receptor type II (Tf3R11) and type I (TpRI) serine/threonine kinases, whereby Srnad2 and Smad3 are phosphorylated and activated, promoting their association with Smadzi. We report here that T beta RI interacts with the SH3 domains of the adaptor protein CIN85 in response to TGF beta stimulation in a TRAF6-dependent manner. Small interfering RNA mediated knockdown of CIN85 resulted in accumulation of T beta RI in intracellular compartments and diminished TGF beta-stimulated Sniad2 phosphorylation. Overexpression of CIN85 instead increased the amount of T beta RI at the cell surface. This effect was inhibited by a dominant-negative mutant of Rab11, suggesting that CIN85 promoted recycling of TGF beta receptors. CIN85 enhanced TGF beta-stimulated Smad2 phosphorylation, transcriptional responses, and cell migration. CIN85 expression correlated with the degree of malignancy of prostate cancers. Collectively, our results reveal that CIN85 promotes recycling of TGF beta receptors and thereby positively regulates TGF beta signaling.
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| 14. |
- Zang, Guangxiang, et al.
(författare)
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Aberrant association between vascular endothelial growth factor receptor-2 and VE-cadherin in response to vascular endothelial growth factor-a in Shb-deficient lung endothelial cells
- 2013
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Ingår i: Cellular Signalling. - : Elsevier BV. - 0898-6568 .- 1873-3913. ; 25:1, s. 85-92
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Tidskriftsartikel (refereegranskat)abstract
- Vascular permeability is a hallmark response to the main angiogenic factor VEGF-A and we have previously described a reduction of this response in Shb knockout mice. To characterize the molecular mechanisms responsible for this effect, endothelial cells were isolated from lungs and analyzed in vitro. Shb deficient endothelial cells exhibited less migration in a scratch wound-healing assay both under basal conditions and after vascular endothelial growth factor-A (VEGF-A) stimulation, suggesting a functional impairment of these cells in vitro. Staining for VE-cadherin and vascular endothelial growth factor receptor-2 (VEGFR-2) showed co-localization in adherens junctions and in intracellular sites such as the perinuclear region in wild-type and Shb knockout cells. VEGF-A decreased the VE-cadherin/VEGFR-2 co-localization in membrane structures resembling adherens junctions in wild-type cells whereas no such response was noted in the Shb knockout cells. VE-cadherin/VEGFR-2 co-localization was also recorded using spinning-disc confocal microscopy and VEGF-A caused a reduced association in the wild-type cells whereas the opposite pattern was observed in the Shb knockout cells. The latter expressed slightly more of cell surface VEGFR-2. VEGF-A stimulated extracellular-signal regulated kinase, Akt and Rac1 activities in the wild-type cells whereas no such responses were noted in the knockout cells. We conclude that aberrant signaling characteristics with respect to ERK, Akt and Rac1 are likely explanations for the observed altered pattern of VE-cadherin/VEGFR-2 association. The latter is important for understanding the reduced in vivo vascular permeability response in Shb knockout mice, a phenomenon that has patho-physiological relevance.
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| 15. |
- Zang, Guangxiang, et al.
(författare)
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Activated pancreatic stellate cells can impair pancreatic islet function in mice
- 2015
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Ingår i: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 120:3, s. 169-180
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Tidskriftsartikel (refereegranskat)abstract
- Background. Pancreatic or islet fibrosis is often associated with activated pancreatic stellate cells (PSCs). PSCs are considered not only to promote fibrosis, but also to be associated with glucose intolerance in some diseases. We therefore evaluated morphological and functional relationships between islets and PSCs in the normal mouse pancreas and transplanted islets. Methods. Immunohistochemistry was used to map the presence of PSCs in the normal mouse pancreas and islets implanted under the renal capsule. We isolated and cultured mouse PSCs and characterized them morphologically by immunofluorescence staining. Furthermore, we measured their cytokine production and determined their effects on insulin release from simultaneously cultured islets. Results. PSCs were scattered throughout the pancreas, with occasional cells within the islets, particularly in the islet capsule. In islet transplants they were found mainly in the graft periphery. Cultured PSCs became functionally activated and produced several cytokines. Throughout the culture period they linearly increased their production of interleukin-6 and mammalian keratinocyte-derived chemokine. PSC cytokine production was not affected by acute hyperglycemia. Syngeneic islets cocultured with PSCs for 24-48 h increased their insulin release and lowered their insulin content. However, short-term insulin release in batch-type incubations was unaffected after 48 h of co-culture. Increased islet cell caspase-3 activation and a decreased islet cell replication were consistently observed after co-culture for 2 or 7 days. Conclusion. Activated PSCs may contribute to impaired islet endocrine function seen in exocrine pancreatitis and in islet fibrosis associated with some cases of type 2 diabetes.
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| 16. |
- Zang, Guangxiang, et al.
(författare)
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PKC sigma facilitates lymphatic metastatic spread of prostate cancer cells in a mice xenograft model
- 2019
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Ingår i: Oncogene. - : Nature Publishing Group. - 0950-9232 .- 1476-5594. ; 38:22, s. 4215-4231
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Tidskriftsartikel (refereegranskat)abstract
- Prostate cancer disseminates primarily into the adjacent lymph nodes, which is related to a poor outcome. Atypical protein kinase C ζ (PKCζ) is highly expressed in aggressive prostate cancer and correlates with Gleason score, clinical stage, and poor prognosis. Here, we report the molecular mechanisms of PKCζ in lymphatic metastasis during prostate cancer progression. Using zinc-finger nuclease technology or PKCζ shRNA lentiviral particles, and orthotopic mouse xenografts, we show that PKCζ-knockout or knockdown from aggressive prostate cancer (PC3 and PC3U) cells, decreasesd tumor growth and lymphatic metastasis in vivo. Intriguingly, PKCζ-knockout or knockdown impaired the activation of AKT, ERK, and NF-κB signaling in prostate cancer cells, thereby impairing the expression of lymphangiogenic factors and macrophage recruitment, resulting in aberrant lymphangiogenesis. Moreover, PKCζ regulated the expression of hyaluronan synthase enzymes, which is important for hyaluronan-mediated lymphatic drainage and tumor dissemination. Thus, PKCζ plays a crucial oncogenic role in the lymphatic metastasis of prostate cancer and is predicted to be a novel therapeutic target for prostate cancer.
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| 17. |
- Zang, Guangxiang, et al.
(författare)
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Vascular dysfunction and increased metastasis of B16F10 melanomas in Shb deficient mice as compared with their wild type counterparts
- 2015
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Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background Shb is a signaling protein downstream of vascular endothelial growth factor receptor-2 and Shb deficiency has been found to restrict tumor angiogenesis. The present study was performed in order to assess metastasis in Shb deficiency using B16F10 melanoma cells. Methods B16F10 melanoma cells were inoculated subcutaneously on wild type or Shb +/− mice. Primary tumors were resected and lung metastasis determined after tumor relapse. Lung metastasis was also assessed after bone marrow transplantation of wild type bone marrow to Shb +/− recipients and Shb +/− bone marrow to wild type recipients. Primary tumors were subject to immunofluorescence staining for CD31, VE-cadherin, desmin and CD8, RNA isolation and isolation of vascular fragments for further RNA isolation. RNA was used for real-time RT-PCR and microarray analysis. Results Numbers of lung metastases were increased in Shb +/− or −/− mice and this coincided with reduced pericyte coverage and increased vascular permeability. Gene expression profiling of vascular fragments isolated from primary tumors and total tumor RNA revealed decreased expression of different markers for cytotoxic T cells in tumors grown on Shb +/− mice, suggesting that vascular aberrations caused altered immune responses. Conclusions It is concluded that a unique combinatorial response of increased vascular permeability and reduced recruitment of cytotoxic CD8+ cells occurs as a consequence of Shb deficiency in B16F10 melanomas. These changes may promote tumor cell intravasation and metastasis.
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| 18. |
- Åkerblom, Björn, et al.
(författare)
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Heterogeneity among RIP-Tag2 insulinomas allows vascular endothelial growth factor-A independent tumor expansion as revealed by studies in Shb mutant mice : implications for tumor angiogenesis
- 2012
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Ingår i: Molecular Oncology. - : Wiley. - 1574-7891 .- 1878-0261. ; 6:3, s. 333-346
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Tidskriftsartikel (refereegranskat)abstract
- The Shb adapter protein is a signaling intermediate that operates downstream of vascular endothelial growth factor receptor-2 (VEGFR-2) in endothelial cells. The Shb knockout mouse displays a dysfunctional microvasculature and impaired growth of subcutaneously implanted tumor cells. We decided to investigate tumor growth and angiogenesis in the absence of Shb in an inheritable tumor model, the RIP-Tag2 mouse, which produces insulinomas in a manner highly dependent on de novo angiogenesis. We observed a reduced tumor incidence and burden in both RIP-Tag2 Shb-/- and RIP-Tag2 Shb+/- mice. This correlated with a reduced microvascular density, measured as percentage of insulinoma area positive for CD31 staining, and altered vascular morphology. However, treatment with a VEGF-A blocking antibody was without effect on the Shb mutant tumor volume whereas it significantly inhibited tumor volume in the wild-type mice, suggesting that in mice with reduced Shb expression tumor angiogenesis was primarily sustained by VEGF-A independent pathway(s). This notion was further substantiated by gene expression analysis of angiogenic markers showing reduced VEGF-A expression in Shb deficient tumors. Considerable heterogeneity with respect to the gene expression profiles of other angiogenic markers and the signal-transduction characteristics was observed between different tumors, suggesting that multiple “rescue” pathways could be operating. The numbers of invasive tumors or metastases were unchanged in the Shb mutant. It is concluded that the Shb mutant background reduces tumor frequency by chronically suppressing VEGF-A dependent angiogenesis. However, VEGF-A independent angiogenesis supports a significant degree of tumor expansion in Shbdeficient mice, indicating heterogeneity in the mechanisms by which tumor expansion is promoted. Interference with Shb signaling may provide novel means for future cancer therapy.
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