TY  - JOUR
A1  - Effenberger, Madlen
A1  - Bommert, Kathryn S.
A1  - Kunz, Viktoria
A1  - Kruk, Jessica
A1  - Leich, Ellen
A1  - Rudelius, Martina
A1  - Bargou, Ralf
A1  - Bommert, Kurt
T1  - Glutaminase inhibition in multiple myeloma induces apoptosis via MYC degradation
JF  - Oncotarget
N2  - Multiple Myeloma (MM) is an incurable hematological malignancy affecting millions of people worldwide. As in all tumor cells both glucose and more recently glutamine have been identified as important for MM cellular metabolism, however there is some dispute as to the role of glutamine in MM cell survival. Here we show that the small molecule inhibitor compound 968 effectively inhibits glutaminase and that this inhibition induces apoptosis in both human multiple myeloma cell lines (HMCLs) and primary patient material. The HMCL U266 which does not express MYC was insensitive to both glutamine removal and compound 968, but ectopic expression of MYC imparted sensitivity. Finally, we show that glutamine depletion is reflected by rapid loss of MYC protein which is independent of MYC transcription and post translational modifications. However, MYC loss is dependent on proteasomal activity, and this loss was paralleled by an equally rapid induction of apoptosis. These findings are in contrast to those of glucose depletion which largely affected rates of proliferation in HMCLs, but had no effects on either MYC expression or viability. Therefore, inhibition of glutaminolysis is effective at inducing apoptosis and thus serves as a possible therapeutic target in MM.
KW  - Multiple Myeloma
KW  - glutaminase inhibition
KW  - apoptosis
KW  - MYC
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170168
VL  - 8
IS  - 49
ER  - 
TY  - JOUR
A1  - Schlereth, Katharina
A1  - Heyl, Charlotte
A1  - Krampitz, Anna-Maria
A1  - Mernberger, Marco
A1  - Finkernagel, Florian
A1  - Scharfe, Maren
A1  - Jarek, Michael
A1  - Leich, Ellen
A1  - Rosenwald, Andreas
A1  - Stiewe, Thorsten
T1  - Characterization of the p53 Cistrome - DNA Binding Cooperativity Dissects p53's Tumor Suppressor Functions
JF  - PLOS Genetics
N2  - p53 protects us from cancer by transcriptionally regulating tumor suppressive programs designed to either prevent the development or clonal expansion of malignant cells. How p53 selects target genes in the genome in a context-and tissue-specific manner remains largely obscure. There is growing evidence that the ability of p53 to bind DNA in a cooperative manner prominently influences target gene selection with activation of the apoptosis program being completely dependent on DNA binding cooperativity. Here, we used ChIP-seq to comprehensively profile the cistrome of p53 mutants with reduced or increased cooperativity. The analysis highlighted a particular relevance of cooperativity for extending the p53 cistrome to non-canonical binding sequences characterized by deletions, spacer insertions and base mismatches. Furthermore, it revealed a striking functional separation of the cistrome on the basis of cooperativity; with low cooperativity genes being significantly enriched for cell cycle and high cooperativity genes for apoptotic functions. Importantly, expression of high but not low cooperativity genes was correlated with superior survival in breast cancer patients. Interestingly, in contrast to most p53-activated genes, p53-repressed genes did not commonly contain p53 binding elements. Nevertheless, both the degree of gene activation and repression were cooperativity-dependent, suggesting that p53-mediated gene repression is largely indirect and mediated by cooperativity-dependently transactivated gene products such as CDKN1A, E2F7 and non-coding RNAs. Since both activation of apoptosis genes with non-canonical response elements and repression of pro-survival genes are crucial for p53's apoptotic activity, the cistrome analysis comprehensively explains why p53-induced apoptosis, but not cell cycle arrest, strongly depends on the intermolecular cooperation of p53 molecules as a possible safeguard mechanism protecting from accidental cell killing.
KW  - cell-cycle arrest
KW  - gene expression
KW  - breast cancer
KW  - human genome
KW  - transcriptional repression
KW  - consensus DNA
KW  - in-vivo
KW  - apoptosis
KW  - network
KW  - damage
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127579
SN  - 1553-7404
VL  - 9
IS  - 8
ER  -