TY  - JOUR
A1  - Engel, Katharina
A1  - Rudelius, Martina
A1  - Slawska, Jolanta
A1  - Jacobs, Laura
A1  - Abhari, Behnaz Ahangarian
A1  - Altmann, Bettina
A1  - Kurutz, Julia
A1  - Rathakrishnan, Abirami
A1  - Fernández-Sáiz, Vanesa
A1  - Brunner, Andrä
A1  - Targosz, Bianca-Sabrina
A1  - Loewecke, Felicia
A1  - Gloeckner, Christian Johannes
A1  - Ueffing, Marius
A1  - Fulda, Simone
A1  - Pfreundschuh, Michael
A1  - Trümper, Lorenz
A1  - Klapper, Wolfram
A1  - Keller, Ulrich
A1  - Jost, Philipp J.
A1  - Rosenwald, Andreas
A1  - Peschel, Christian
A1  - Bassermann, Florian
T1  - USP9X stabilizes XIAP to regulate mitotic cell death and chemoresistance in aggressive B-cell lymphoma
JF  - EMBO Molecular Medicine
N2  - The mitotic spindle assembly checkpoint (SAC) maintains genome stability and marks an important target for antineoplastic therapies. However, it has remained unclear how cells execute cell fate decisions under conditions of SAC‐induced mitotic arrest. Here, we identify USP9X as the mitotic deubiquitinase of the X‐linked inhibitor of apoptosis protein (XIAP) and demonstrate that deubiquitylation and stabilization of XIAP by USP9X lead to increased resistance toward mitotic spindle poisons. We find that primary human aggressive B‐cell lymphoma samples exhibit high USP9X expression that correlate with XIAP overexpression. We show that high USP9X/XIAP expression is associated with shorter event‐free survival in patients treated with spindle poison‐containing chemotherapy. Accordingly, aggressive B‐cell lymphoma lines with USP9X and associated XIAP overexpression exhibit increased chemoresistance, reversed by specific inhibition of either USP9X or XIAP. Moreover, knockdown of USP9X or XIAP significantly delays lymphoma development and increases sensitivity to spindle poisons in a murine Eμ‐Myc lymphoma model. Together, we specify the USP9X–XIAP axis as a regulator of the mitotic cell fate decision and propose that USP9X and XIAP are potential prognostic biomarkers and therapeutic targets in aggressive B‐cell lymphoma.
KW  - B‐cell lymphoma
KW  - mitosis
KW  - ubiquitin
KW  - USP9X
KW  - XIAP
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-165016
VL  - 8
ER  - 
TY  - JOUR
A1  - Lapa, Constantin
A1  - Lückerath, Katharina
A1  - Kleinlein, Irene
A1  - Monoranu, Camelia Maria
A1  - Linsenmann, Thomas
A1  - Kessler, Almuth F.
A1  - Rudelius, Martina
A1  - Kropf, Saskia
A1  - Buck, Andreas K.
A1  - Ernestus, Ralf-Ingo
A1  - Wester, Hans-Jürgen
A1  - Löhr, Mario
A1  - Herrmann, Ken
T1  - \(^{68}\)Ga-Pentixafor-PET/CT for Imaging of Chemokine Receptor 4 Expression in Glioblastoma
JF  - Theranostics
N2  - Chemokine receptor-4 (CXCR4) has been reported to be overexpressed in glioblastoma (GBM) and to be associated with poor survival. This study investigated the feasibility of non-invasive CXCR4-directed imaging with positron emission tomography/computed tomography (PET/CT) using the radiolabelled chemokine receptor ligand \(^{68}\)Ga-Pentixafor.
15 patients with clinical suspicion on primary or recurrent glioblastoma (13 primary, 2 recurrent tumors) underwent \(^{68}\)Ga-Pentixafor-PET/CT for assessment of CXCR4 expression prior to surgery. O-(2-\(^{18}\)F-fluoroethyl)-L-tyrosine (\(^{18}\)F-FET) PET/CT images were available in 11/15 cases and were compared visually and semi-quantitatively (SUV\(_{max}\), SUV\(_{mean}\)). Tumor-to-background ratios (TBR) were calculated for both PET probes. \(^{68}\)Ga-Pentixafor-PET/CT results were also compared to histological CXCR4 expression on neuronavigated surgical samples.
\(^{68}\)Ga-Pentixafor-PET/CT was visually positive in 13/15 cases with SUV\(_{mean}\) and SUV\(_{max}\) of 3.0±1.5 and 3.9±2.0 respectively. Respective values for \(^{18}\)F-FET were 4.4±2.0 (SUV\(_{mean}\)) and 5.3±2.3 (SUV\(_{max}\)). TBR for SUV\(_{mean}\) and SUV\(_{max}\) were higher for \(^{68}\)Ga-Pentixafor than for \(^{18}\)F-FET (SUV\(_{mean}\) 154.0±90.7 vs. 4.1±1.3; SUV\(_{max}\) 70.3±44.0 and 3.8±1.2, p<0.01), respectively. Histological analysis confirmed CXCR4 expression in tumor areas with high \(^{68}\)Ga-Pentixafor uptake; regions of the same tumor without apparent \(^{68}\)Ga-Pentixafor uptake showed no or low receptor expression.
In this pilot study, \(^{68}\)Ga-Pentixafor retention has been observed in the vast majority of glioblastoma lesions and served as readout for non-invasive determination of CXCR4 expression. Given the paramount importance of the CXCR4/SDF-1 axis in tumor biology, \(^{68}\)Ga-Pentixafor-PET/CT might prove a useful tool for sensitive, non-invasive in-vivo quantification of CXCR4 as well as selection of patients who might benefit from CXCR4-directed therapy.
KW  - imaging
KW  - chemokine receptor-4
KW  - glioblastoma
KW  - positron emission tomography/computed tomography
KW  - \(^{68}\)Ga-Pentixafor
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-168174
VL  - 6
IS  - 3
ER  -