TY  - JOUR
A1  - Kunz, Viktoria
A1  - Bommert, Kathryn S.
A1  - Kruk, Jessica
A1  - Schwinning, Daniel
A1  - Chatterjee, Manik
A1  - Stühmer, Thorsten
A1  - Bargou, Ralf
A1  - Bommert, Kurt
T1  - Targeting of the E3 ubiquitin-protein ligase HUWE1 impairs DNA repair capacity and tumor growth in preclinical multiple myeloma models
JF  - Scientific Reports
N2  - Experimental evidence suggests that ubiquitin-protein ligases regulate a number of cellular processes involved in tumorigenesis. We analysed the role of the E3 ubiquitin-protein ligase HUWE1 for pathobiology of multiple myeloma (MM), a still incurable blood cancer. mRNA expression analysis indicates an increase in HUWE1 expression levels correlated with advanced stages of myeloma. Pharmacologic as well as RNAi-mediated HUWE1 inhibition caused anti-proliferative effects in MM cell lines in vitro and in an MM1.S xenotransplantation mouse model. Cell cycle analysis upon HUWE1 inhibition revealed decreased S phase cell fractions. Analyses of potential HUWE1-dependent molecular functions did not show involvement in MYC-dependent gene regulation. However, HUWE1 depleted MM cells displayed increased DNA tail length by comet assay, as well as changes in the levels of DNA damage response mediators such as pBRCA1, DNA-polymerase beta, gamma H2AX and Mcl-1. Our finding that HUWE1 might thus be involved in endogenous DNA repair is further supported by strongly enhanced apoptotic effects of the DNA-damaging agent melphalan in HUWE1 depleted cells in vitro and in vivo. These data suggest that HUWE1 might contribute to tumour growth by endogenous repair of DNA, and could therefore potentially be exploitable in future treatment developments.
KW  - MYC
KW  - interacts
KW  - gene
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230632
VL  - 10
ER  - 
TY  - JOUR
A1  - Weißbach, Susann
A1  - Heredia-Guerrero, Sofia Catalina
A1  - Barnsteiner, Stefanie
A1  - Großhans, Lukas
A1  - Bodem, Jochen
A1  - Starz, Hanna
A1  - Langer, Christian
A1  - Appenzeller, Silke
A1  - Knop, Stefan
A1  - Steinbrunn, Torsten
A1  - Rost, Simone
A1  - Einsele, Hermann
A1  - Bargou, Ralf Christian
A1  - Rosenwald, Andreas
A1  - Stühmer, Thorsten
A1  - Leich, Ellen
T1  - Exon-4 Mutations in KRAS Affect MEK/ERK and PI3K/AKT Signaling in Human Multiple Myeloma Cell Lines
JF  - Cancers
N2  - Approximately 20% of multiple myeloma (MM) cases harbor a point mutation in KRAS. However, there is still no final consent on whether KRAS-mutations are associated with disease outcome. Specifically, no data exist on whether KRAS-mutations have an impact on survival of MM patients at diagnosis in the era of novel agents. Direct blockade of KRAS for therapeutic purposes is mostly impossible, but recently a mutation-specific covalent inhibitor targeting KRAS\(^{p.G12C}\) entered into clinical trials. However, other KRAS hotspot-mutations exist in MM patients, including the less common exon-4 mutations. For the current study, the coding regions of KRAS were deep-sequenced in 80 newly diagnosed MM patients, uniformely treated with three cycles of bortezomib plus dexamethasone and cyclophosphamide (VCD)-induction, followed by high-dose chemotherapy and autologous stem cell transplantation. Moreover, the functional impact of KRAS\(^{p.G12A}\) and the exon-4 mutations p.A146T and p.A146V on different survival pathways was investigated. Specifically, KRAS\(^{WT}\), KRAS\(^{p.G12A}\), KRAS\(^{p.A146T}\), and KRAS\(^{p.A146V}\) were overexpressed in HEK293 cells and the KRAS\(^{WT}\) MM cell lines JJN3 and OPM2 using lentiviral transduction and the Sleeping Beauty vector system. Even though KRAS-mutations were not correlated with survival, all KRAS-mutants were found capable of potentially activating MEK/ERK- and sustaining PI3K/AKT-signaling in MM cells.
KW  - multiple myeloma
KW  - KRAS
KW  - MEK/ERK-signaling
KW  - AKT-signaling
KW  - amplicon sequencing
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200617
SN  - 2072-6694
VL  - 12
IS  - 2
ER  -