@article{MederKoenigOzretićetal.2016, author = {Meder, Lydia and K{\"o}nig, Katharina and Ozretić, Luka and Schultheis, Anne M. and Ueckeroth, Frank and Ade, Carsten P. and Albus, Kerstin and Boehm, Diana and Rommerscheidt-Fuss, Ursula and Florin, Alexandra and Buhl, Theresa and Hartmann, Wolfgang and Wolf, J{\"u}rgen and Merkelbach-Bruse, Sabine and Eilers, Martin and Perner, Sven and Heukamp, Lukas C. and Buettner, Reinhard}, title = {NOTCH, ASCL1, p53 and RB alterations define an alternative pathway driving neuroendocrine and small cell lung carcinomas}, series = {International Journal of Cancer}, volume = {138}, journal = {International Journal of Cancer}, number = {4}, doi = {10.1002/ijc.29835}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-190853}, pages = {927-938}, year = {2016}, abstract = {Small cell lung cancers (SCLCs) and extrapulmonary small cell cancers (SCCs) are very aggressive tumors arising de novo as primary small cell cancer with characteristic genetic lesions in RB1 and TP53. Based on murine models, neuroendocrine stem cells of the terminal bronchioli have been postulated as the cellular origin of primary SCLC. However, both in lung and many other organs, combined small cell/non-small cell tumors and secondary transitions from non-small cell carcinomas upon cancer therapy to neuroendocrine and small cell tumors occur. We define features of "small cell-ness" based on neuroendocrine markers, characteristic RB1 and TP53 mutations and small cell morphology. Furthermore, here we identify a pathway driving the pathogenesis of secondary SCLC involving inactivating NOTCH mutations, activation of the NOTCH target ASCL1 and canonical WNT-signaling in the context of mutual bi-allelic RB1 and TP53 lesions. Additionaly, we explored ASCL1 dependent RB inactivation by phosphorylation, which is reversible by CDK5 inhibition. We experimentally verify the NOTCH-ASCL1-RB-p53 signaling axis in vitro and validate its activation by genetic alterations in vivo. We analyzed clinical tumor samples including SCLC, SCC and pulmonary large cell neuroendocrine carcinomas and adenocarcinomas using amplicon-based Next Generation Sequencing, immunohistochemistry and fluorescence in situ hybridization. In conclusion, we identified a novel pathway underlying rare secondary SCLC which may drive small cell carcinomas in organs other than lung, as well.}, language = {en} } @article{BoehmMeiningerTeschetal.2018, author = {Boehm, Anne and Meininger, Susanne and Tesch, Annemarie and Gbureck, Uwe and M{\"u}ller, Frank A.}, title = {The mechanical properties of biocompatible apatite bone cement reinforced with chemically activated carbon fibers}, series = {Materials}, volume = {11}, journal = {Materials}, number = {2}, issn = {1996-1944}, doi = {10.3390/ma11020192}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-197808}, pages = {192}, year = {2018}, abstract = {Calcium phosphate cement (CPC) is a well-established bone replacement material in dentistry and orthopedics. CPC mimics the physicochemical properties of natural bone and therefore shows excellent in vivo behavior. However, due to their brittleness, the application of CPC implants is limited to non-load bearing areas. Generally, the fiber-reinforcement of ceramic materials enhances fracture resistance, but simultaneously reduces the strength of the composite. Combining strong C-fiber reinforcement with a hydroxyapatite to form a CPC with a chemical modification of the fiber surface allowed us to adjust the fiber-matrix interface and consequently the fracture behavior. Thus, we could demonstrate enhanced mechanical properties of CPC in terms of bending strength and work of fracture to a strain of 5\% (WOF5). Hereby, the strength increased by a factor of four from 9.2 ± 1.7 to 38.4 ± 1.7 MPa. Simultaneously, the WOF5 increased from 0.02 ± 0.004 to 2.0 ± 0.6 kJ∙m-2, when utilizing an aqua regia/CaCl2 pretreatment. The cell proliferation and activity of MG63 osteoblast-like cells as biocompatibility markers were not affected by fiber addition nor by fiber treatment. CPC reinforced with chemically activated C-fibers is a promising bone replacement material for load-bearing applications.}, language = {en} } @article{SeifertGrollWeichholdetal.2021, author = {Seifert, Annika and Groll, J{\"u}rgen and Weichhold, Jan and Boehm, Anne V. and M{\"u}ller, Frank A. and Gbureck, Uwe}, title = {Phase Conversion of Ice-Templated α-Tricalcium Phosphate Scaffolds into Low-Temperature Calcium Phosphates with Anisotropic Open Porosity}, series = {Advanced Engineering Materials}, volume = {23}, journal = {Advanced Engineering Materials}, number = {5}, doi = {10.1002/adem.202001417}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256311}, year = {2021}, abstract = {The current study aims to extend the material platform for anisotropically structured calcium phosphates to low-temperature phases such as calcium-deficient hydroxyapatite (CDHA) or the secondary phosphates monetite and brushite. This is achieved by the phase conversion of highly porous α-tricalcium phosphate (α-TCP) scaffolds fabricated by ice-templating into the aforementioned phases by hydrothermal treatment or incubation in phosphoric acid. Prior to these steps, α-TCP scaffolds are either sintered for 8 h at 1400 °C or remain in their original state. Both nonsintered and sintered α-TCP specimens are converted into CDHA by hydrothermal treatment, while a transformation into monetite and brushite is achieved by incubation in phosphoric acid. Hydrothermal treatment for 72 h at 175 °C increases the porosity in nonsintered samples from 85\% to 88\% and from 75\% to 88\% in the sintered ones. An increase in the specific surface area from (1.102 ± 0.005) to (9.17 ± 0.01) m2 g-1 and from (0.190 ± 0.004) to (2.809 ± 0.002) m2 g-1 due to the phase conversion is visible for both the nonsintered and sintered samples. Compressive strength of the nonsintered samples increases significantly from (0.76 ± 0.11) to (5.29 ± 0.94) MPa due to incubation in phosphoric acid.}, language = {en} }