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Ungefroren H.,Clinic for Applied Cellular Medicine
Advances in Experimental Medicine and Biology | Year: 2010

Adult stem or programmable cells hold great promise in diseases in which damaged or non-functional cells need to be replaced, such as in type 1 diabetes. We have recently demonstrated that peripheral blood monocytes can be differentiated in vitro into pancreatic β-cell-like cells capable of synthesizing insulin. The two-step phenotypic conversion commences with growth factor-induced partial reprogramming during which the cells acquire a state of plasticity along with expression of various markers of pluripotency. These cells, termed "programmable cells of monocytic origin" (PCMOs), can then be induced with appropriate differentiation media to become insulin-producing cells (NeoIslet cells). Expression profiling of transcription factors known to determine endocrine and β-cell development in vivo indicated that NeoIslet cells resemble cells with an immature β-cell phenotype. Current efforts focus on establishing culture conditions that (i) increase the plasticity and proliferation potential of PCMOs by enhancing the reprogramming process and (ii) improve insulin production by mimicking in vivo lineage specification and normal pancreatic endocrine development. Combining these two strategies has great potential in generating large amounts of blood-derived cells suitable for both autologous and allogeneic therapy of type 1 diabetes. © Springer Science+Business Media B.V. 2010. Source


Held-Feindt J.,University of Kiel | Hattermann K.,University of Kiel | Muerkoster S.S.,Laboratory of Molecular Gastroenterology and Hepatology | Wedderkopp H.,University of Kiel | And 4 more authors.
Experimental Cell Research | Year: 2010

The transmembrane chemokine CX3CL1 and its receptor CX3CR1 are thought to be involved in the trafficking of immune cells during an immune response and in the pathology of various human diseases including cancer. However, little is known about the expression and function of CX3CR1 in human glioma-infiltrating microglia/macrophages (GIMs), representing the major cellular stroma component of highly malignant gliomas. Here, we show that CX3CR1 is overexpressed at both the mRNA and protein level in solid human astrocytomas of different malignancy grades and in glioblastomas. CX3CR1 was localized in ionized calcium-binding adapter molecule 1 (Iba1) and CD11b/c positive GIMs in situ as shown by fluorescence microscopy. In accordance with this, freshly isolated human GIM-enriched fractions separated by CD11b MACS technology displayed high Iba1 and CX3CR1 mRNA expression levels in vitro. Moreover, cultured human GIMs responded to CX3CL1-triggered activation of CX3CR1 with adhesion and migration in vitro. Besides an increase in motility, CX3CL1 also enhanced expression of matrix metalloproteases 2, 9, and 14 in GIM fractions in vitro. These data indicate that the CX3CL1/CX3CR1 system has a crucial tumor-promoting role in human glioblastomas via its impact on glioma-infiltrating immune subsets. © 2010. Source


Ungefroren H.,UKSH | Hyder A.,Clinic for Applied Cellular Medicine | Hyder A.,Damietta University | Schulze M.,University of Duisburg - Essen | And 5 more authors.
Stem Cells International | Year: 2016

Adult stem or programmable cells hold great promise in diseases in which damaged or nonfunctional cells need to be replaced. We have recently demonstrated that peripheral blood monocytes can be differentiated in vitro into cells resembling specialized cell types like hepatocytes and pancreatic beta cells. During phenotypic conversion, the monocytes downregulate monocyte/macrophage differentiation markers, being indicative of partial dedifferentiation, and are partially reprogrammed to acquire a state of plasticity along with expression of various markers of pluripotency and resumption of mitosis. Upregulation of stem cell markers and mitotic activity in the cultures was shown to be controlled by autocrine production/secretion of activin A and transforming growth factor-beta (TGF-β). These reprogrammed monocyte derivatives were termed "programmable cells of monocytic origin" (PCMO). Current efforts focus on establishing culture conditions that increase both the plasticity and proliferation potential of PCMO in order to be able to generate large amounts of blood-derived cells suitable for both autologous and allogeneic therapies. © 2016 Hendrik Ungefroren et al. Source


Ungefroren H.,Clinic for Applied Cellular Medicine | Sebens S.,University of Kiel | Sebens S.,C o Laboratory of Molecular Gastroenterology and Hepatology | Groth S.,Clinic for Applied Cellular Medicine | And 2 more authors.
International Journal of Oncology | Year: 2011

Both transforming growth factor (TGF)-β and the non-receptor tyrosine kinase Src play major roles during tumorigenesis by regulating cell growth, epithelial-to-mesenchymal transition (EMT), migration/invasion and metastasis, but little is known about the signaling crosstalk between them. To interfere with Src function in vitro and in vivo many studies have employed the pharmacologic Src inhibitors PP2 and PP1. Both agents have recently been shown to be powerful inhibitors of TGF-β receptor type I/ALK5 and type II. As this situation prohibited any definite conclusions with respect to the relative contribution of TGF-β vs. Src signaling, we decided to reappraise a potential role of Src in TGF-β1-mediated cellular responses using RNA and dominant-negative (dn) interference to block Src expression and function, respectively. In TGF-β-responsive pancreatic ductal adenocarcinoma (PDAC) cells, we show that Src is activated by TGF-β1 and that its specific inhibition strongly attenuated basal proliferation and enhanced TGF-β1-mediated growth arrest. However, Src inhibition was unable to impair TGF-β1-controlled EMT as evidenced by cell morphology and regulation of the epithelial marker E-cadherin. Despite its dispensibility for TGF-β-induced EMT, specific inhibition of Src dramatically reduced basal and TGF-β1-induced cell migration in Panc-1 cells as measured with a novel real-time migration assay (xCELLigence DP system). Biochemically, dnSrc inhibition failed to block TGF-β1/ALK5-induced activation of Smad2 and Smad3, but partially inhibited transcriptional activation of TGF-β/Smad-responsive reporter genes, and effectively blocked basal and TGF-β1-induced activation of p38 MAPK. Together, the data provide evidence for a role of Src in the regulation of basal proliferation as well as in basal and TGFβ1-mediated cell motility but not EMT in TGF-β-responsive pancreatic (tumor) cells. Source


Ungefroren H.,Clinic for Applied Cellular Medicine | Sebens S.,University of Kiel | Sebens S.,Laboratory of Molecular Gastroenterology and Hepatology | Groth S.,Clinic for Applied Cellular Medicine | And 2 more authors.
Current Cancer Drug Targets | Year: 2011

Both the nonreceptor tyrosine kinase Src and the receptors for transforming growth factor (TGF)-β (TβRI, TβRII) play major roles during tumorigenesis by regulating cell growth, migration/invasion and metastasis. The common Src family kinase inhibitors PP2 and PP1 effectively block Src activity in vitro and in vivo, however, they may exert nonspecific effects on other kinases. In this study, we have evaluated PP2 and PP1 for their ability to inhibit TGFβ1-mediated responses in the TGF-β-responsive pancreatic adenocarcinoma cell line Panc1. We show that PP2 and PP1 but not the more specific Src inhibitor SU6656 effectively relieved TGF-β1-induced growth arrest and p21WAF1 induction, while basal growth was enhanced by PP2 and PP1, and suppressed by SU6656. PP2 and PP1 but not SU6656 also suppressed TGF-β1-induced epithelial-to-mesenchymal transition (EMT) as evidenced by their ability to inhibit downregulation of the epithelial marker E-cadherin, and upregulation of the EMT-associated transcription factor Slug. Likewise, PP2 and PP1 but not SU6656 effectively blocked TGF-β1-induced activation of Smad2 and p38 MAPK and partially suppressed Smad activation and transcriptional activity on TGF-β/Smad-responsive reporters of a kinase-active TβRI mutant ectopically expressed in Panc1 cells. Interestingly, PP2 and PP1 strongly inhibited recombinant TβRI in an in vitro kinase assay, with PP1 being more potent and PP2 being nearly as potent as the established TβRI inhibitor SB431542. PP2 but not PP1 also weakly inhibited the TβRII kinase. Together, these data provide evidence that PP2 and PP1 are powerful inhibitors of TβR function that can block TGF-β/Smad signaling in a Src-unrelated fashion. Both agents may be useful as dual TGF-β/Src inhibitors in experimental therapeutics of late stage metastatic disease. © 2011 Bentham Science Publishers Ltd. Source

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