Browsing by Author "Greve, Burkhard"

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    HS2ST1‐dependent signaling pathways determine breast cancer cell viability, matrix interactions and invasive behavior
    (wiley online library, 6/23/2020) Vijaya Kumar, Archana; Brézillon, Stéphane; Untereiner, Valérie; Dhruvananda Sockalingum, Ganesh; Kumar Katakam, Sampath; Taha Mohamed, Hossam; Kemper, Björn; Greve, Burkhard; Mohr, Benedikt; Ibrahim, Sherif A.; Goycoolea, Francisco M.; Kiesel, Ludwig; Pavão, Mauro S.G.; Motta, Juliana M.; Götte, Martin
    Heparan sulfate proteoglycans (HSPGs) act as signaling coreceptors by interactions of their sulfated glycosaminoglycan chains with numerous signaling molecules. In breast cancer, the function of heparan sulfate 2‐O‐sulfotransferase (HS2ST1 ), the enzyme mediating 2‐O‐sulfation of HS, is largely unknown. Hence, a comparative study on the functional consequences of HS2ST1 overexpression and siRNA knockdown was performed in the breast cancer cell lines MCF‐7 and MDA‐MB‐231. HS2ST1 overexpression inhibited matrigel invasion, while its knockdown reversed the phenotype. Likewise, cell motility and adhesion to fibronectin and laminin were affected by altered HS2ST1 expression. Phosphokinase array screening revealed a general decrease in signaling via multiple pathways. Fluorescent ligand binding studies revealed altered binding of fibroblast growth factor 2 (FGF‐2) to HS2ST1 expressing cells compared to control cells. HS2ST1 overexpressing cells showed reduced MAPK signaling responses to FGF‐2, and altered expression of EGFR, E‐cadherin, Wnt‐7a and Tcf4. The increased viability of HS2ST1 depleted cells was reduced to control levels by pharmacological MAPK pathway inhibition. Moreover, MAPK inhibitors generated a phenocopy of the HS2ST1 ‐dependent delay in scratch wound repair. In conclusion, HS2ST1 modulation of breast cancer cell invasiveness is a compound effect of altered E‐cadherin and EGFR expression, leading to altered signaling via MAPK and additional pathways
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    Syndecan-1 is a novel molecular marker for triple negative inflammatory breast cancer and modulates the cancer stem cell phenotype via the IL-6/STAT3, Notch and EGFR signaling pathways
    (BioMed Central, 2017) Abdelaziz Ibrahim, Sherif; Gadalla, Ramy; A. El-Ghonaimy, Eslam; Samir, Omnia; Taha Mohamed, Hossam; Hassan, Hebatallah; Greve, Burkhard; El-Shinawi, Mohamed; Mostafa Mohamed, Mona; Götte, Martin
    Background Inflammatory breast cancer (IBC), a particularly aggressive form of breast cancer, is characterized by cancer stem cell (CSC) phenotype. Due to a lack of targeted therapies, the identification of molecular markers of IBC is of major importance. The heparan sulfate proteoglycan Syndecan-1 acts as a coreceptor for growth factors and chemokines, modulating inflammation, tumor progression, and cancer stemness, thus it may emerge as a molecular marker for IBC. Methods We characterized expression of Syndecan-1 and the CSC marker CD44, Notch-1 & -3 and EGFR in carcinoma tissues of triple negative IBC (n = 13) and non-IBC (n = 17) patients using qPCR and immunohistochemistry. Impact of siRNA-mediated Syndecan-1 knockdown on the CSC phenotype of the human triple negative IBC cell line SUM-149 and HER-2-overexpressing non-IBC SKBR3 cells employing qPCR, flow cytometry, Western blotting, secretome profiling and Notch pharmacological inhibition experiments. Data were statistically analyzed using Student’s t-test/Mann-Whitney U-test or one-way ANOVA followed by Tukey’s multiple comparison tests. Results Our data indicate upregulation and a significant positive correlation of Syndecan-1 with CD44 protein, and Notch-1 & -3 and EGFR mRNA in IBC vs non-IBC. ALDH1 activity and the CD44(+)CD24(-/low) subset as readout of a CSC phenotype were reduced upon Syndecan-1 knockdown. Functionally, Syndecan-1 silencing significantly reduced 3D spheroid and colony formation. Intriguingly, qPCR results indicate downregulation of the IL-6, IL-8, CCL20, gp130 and EGFR mRNA upon Syndecan-1 suppression in both cell lines. Moreover, Syndecan-1 silencing significantly downregulated Notch-1, -3, -4 and Hey-1 in SUM-149 cells, and downregulated only Notch-3 and Gli-1 mRNA in SKBR3 cells. Secretome profiling unveiled reduced IL-6, IL-8, GRO-alpha and GRO a/b/g cytokines in conditioned media of Syndecan-1 knockdown SUM-149 cells compared to controls. The constitutively activated STAT3 and NFκB, and expression of gp130, Notch-1 & -2, and EGFR proteins were suppressed upon Syndecan-1 ablation. Mechanistically, gamma-secretase inhibition experiments suggested that Syndecan-1 may regulate the expression of IL-6, IL-8, gp130, Hey-1, EGFR and p-Akt via Notch signaling. Conclusions Syndecan-1 acts as a novel tissue biomarker and a modulator of CSC phenotype of triple negative IBC via the IL-6/STAT3, Notch and EGFR signaling pathways, thus emerging as a promising therapeutic target for IBC.