TY  - JOUR
A1  - Graf, Nicolas
A1  - Li, Zhoulei
A1  - Herrmann, Ken
A1  - Weh, Daniel
A1  - Aichler, Michaela
A1  - Slawska, Jolanta
A1  - Walch, Axel
A1  - Peschel, Christian
A1  - Schwaiger, Markus
A1  - Buck, Andreas K.
A1  - Dechow, Tobias
A1  - Keller, Ulrich
T1  - Positron emission tomographic monitoring of dual phosphatidylinositol-3-kinase and mTOR inhibition in anaplastic large cell lymphoma
JF  - Oncotargets and Therapy
N2  - Background: Dual phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) inhibition offers an attractive therapeutic strategy in anaplastic large cell lymphoma depending on oncogenic nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) signaling. We tested the efficacy of a novel dual PI3K/mTOR inhibitor, NVP-BGT226 (BGT226), in two anaplastic large cell lymphoma cell lines in vitro and in vivo and performed an early response evaluation with positron emission tomography (PET) imaging using the standard tracer, 2-deoxy-2-[F-18] fluoro-D-glucose (FDG) and the thymidine analog, 3'-deoxy-3'-[F-18] fluorothymidine (FLT). 
Methods: The biological effects of BGT226 were determined in vitro in the NPM-ALK positive cell lines SU-DHL-1 and Karpas299 by 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay, propidium iodide staining, and biochemical analysis of PI3K and mTOR downstream signaling. FDG-PET and FLT-PET were performed in immunodeficient mice bearing either SU-DHL-1 or Karpas299 xenografts at baseline and 7 days after initiation of treatment with BGT226. Lymphomas were removed for immunohistochemical analysis of proliferation and apoptosis to correlate PET findings with in vivo treatment effects. 
Results: SU-DHL-1 cells showed sensitivity to BGT226 in vitro, with cell cycle arrest in G0/G1 phase and an IC50 in the low nanomolar range, in contrast with Karpas299 cells, which were mainly resistant to BGT226. In vivo, both FDG-PET and FLT-PET discriminated sensitive from resistant lymphoma, as indicated by a significant reduction of tumor-to-background ratios on day 7 in treated SU-DHL-1 lymphoma-bearing animals compared with the control group, but not in animals with Karpas299 xenografts. Imaging results correlated with a marked decrease in the proliferation marker Ki67, and a slight increase in the apoptotic marker, cleaved caspase 3, as revealed by immunostaining of explanted lymphoma tissue. 
Conclusion: Dual PI3K/mTOR inhibition using BGT226 is effective in ALK-positive anaplastic large cell lymphoma and can be monitored with both FDG-PET and FLT-PET early on in the course of therapy.
KW  - mammalian target of rapamycin
KW  - phosphatidylinositol-3-kinase
KW  - lymphoma
KW  - early response
KW  - NVP-BGT226
KW  - non-hodgkins-lymphoma
KW  - signaling pathway
KW  - FDG-PET
KW  - in-vivo
KW  - target
KW  - tumor
KW  - imaging proliferation
KW  - inhibition
KW  - positron emission tomography
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117915
VL  - 7
ER  - 
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  -