TY - JOUR A1 - Otto, Christoph A1 - Kastner, Carolin A1 - Schmidt, Stefanie A1 - Uttinger, Konstantin A1 - Baluapuri, Apoorva A1 - Denk, Sarah A1 - Rosenfeldt, Mathias T. A1 - Rosenwald, Andreas A1 - Roehrig, Florian A1 - Ade, Carsten P. A1 - Schuelein-Voelk, Christina A1 - Diefenbacher, Markus E. A1 - Germer, Christoph-Thomas A1 - Wolf, Elmar A1 - Eilers, Martin A1 - Wiegering, Armin T1 - RNA polymerase I inhibition induces terminal differentiation, growth arrest, and vulnerability to senolytics in colorectal cancer cells JF - Molecular Oncology N2 - Ribosomal biogenesis and protein synthesis are deregulated in most cancers, suggesting that interfering with translation machinery may hold significant therapeutic potential. Here, we show that loss of the tumor suppressor adenomatous polyposis coli (APC), which constitutes the initiating event in the adenoma carcinoma sequence for colorectal cancer (CRC), induces the expression of RNA polymerase I (RNAPOL1) transcription machinery, and subsequently upregulates ribosomal DNA (rDNA) transcription. Targeting RNAPOL1 with a specific inhibitor, CX5461, disrupts nucleolar integrity, and induces a disbalance of ribosomal proteins. Surprisingly, CX5461-induced growth arrest is irreversible and exhibits features of senescence and terminal differentiation. Mechanistically, CX5461 promotes differentiation in an MYC-interacting zinc-finger protein 1 (MIZ1)- and retinoblastoma protein (Rb)-dependent manner. In addition, the inhibition of RNAPOL1 renders CRC cells vulnerable towards senolytic agents. We validated this therapeutic effect of CX5461 in murine- and patient-derived organoids, and in a xenograft mouse model. These results show that targeting ribosomal biogenesis together with targeting the consecutive, senescent phenotype using approved drugs is a new therapeutic approach, which can rapidly be transferred from bench to bedside. KW - CRC KW - CX5461 KW - MIZ1 KW - MYC KW - ribosome KW - RNAPOL1 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312806 VL - 16 IS - 15 ER - TY - JOUR A1 - Hartmann, Oliver A1 - Reissland, Michaela A1 - Maier, Carina R. A1 - Fischer, Thomas A1 - Prieto-Garcia, Cristian A1 - Baluapuri, Apoorva A1 - Schwarz, Jessica A1 - Schmitz, Werner A1 - Garrido-Rodriguez, Martin A1 - Pahor, Nikolett A1 - Davies, Clare C. A1 - Bassermann, Florian A1 - Orian, Amir A1 - Wolf, Elmar A1 - Schulze, Almut A1 - Calzado, Marco A. A1 - Rosenfeldt, Mathias T. A1 - Diefenbacher, Markus E. T1 - Implementation of CRISPR/Cas9 Genome Editing to Generate Murine Lung Cancer Models That Depict the Mutational Landscape of Human Disease JF - Frontiers in Cell and Developmental Biology N2 - Lung cancer is the most common cancer worldwide and the leading cause of cancer-related deaths in both men and women. Despite the development of novel therapeutic interventions, the 5-year survival rate for non-small cell lung cancer (NSCLC) patients remains low, demonstrating the necessity for novel treatments. One strategy to improve translational research is the development of surrogate models reflecting somatic mutations identified in lung cancer patients as these impact treatment responses. With the advent of CRISPR-mediated genome editing, gene deletion as well as site-directed integration of point mutations enabled us to model human malignancies in more detail than ever before. Here, we report that by using CRISPR/Cas9-mediated targeting of Trp53 and KRas, we recapitulated the classic murine NSCLC model Trp53fl/fl:lsl-KRasG12D/wt. Developing tumors were indistinguishable from Trp53fl/fl:lsl-KRasG12D/wt-derived tumors with regard to morphology, marker expression, and transcriptional profiles. We demonstrate the applicability of CRISPR for tumor modeling in vivo and ameliorating the need to use conventional genetically engineered mouse models. Furthermore, tumor onset was not only achieved in constitutive Cas9 expression but also in wild-type animals via infection of lung epithelial cells with two discrete AAVs encoding different parts of the CRISPR machinery. While conventional mouse models require extensive husbandry to integrate new genetic features allowing for gene targeting, basic molecular methods suffice to inflict the desired genetic alterations in vivo. Utilizing the CRISPR toolbox, in vivo cancer research and modeling is rapidly evolving and enables researchers to swiftly develop new, clinically relevant surrogate models for translational research. KW - non-small cell lung cancer KW - CRISPR-Cas9 KW - mouse model KW - lung cancer KW - MYC KW - JUN Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230949 SN - 2296-634X VL - 9 ER - TY - JOUR A1 - Lorenzin, Francesca A1 - Benary, Uwe A1 - Baluapuri, Apoorva A1 - Walz, Susanne A1 - Jung, Lisa Anna A1 - von Eyss, Björn A1 - Kisker, Caroline A1 - Wolf, Jana A1 - Eilers, Martin A1 - Wolf, Elmar T1 - Different promoter affinities account for specificity in MYC-dependent gene regulation JF - eLife N2 - Enhanced expression of the MYC transcription factor is observed in the majority of tumors. Two seemingly conflicting models have been proposed for its function: one proposes that MYC enhances expression of all genes, while the other model suggests gene-specific regulation. Here, we have explored the hypothesis that specific gene expression profiles arise since promoters differ in affinity for MYC and high-affinity promoters are fully occupied by physiological levels of MYC. We determined cellular MYC levels and used RNA- and ChIP-sequencing to correlate promoter occupancy with gene expression at different concentrations of MYC. Mathematical modeling showed that binding affinities for interactions of MYC with DNA and with core promoter-bound factors, such as WDR5, are sufficient to explain promoter occupancies observed in vivo. Importantly, promoter affinity stratifies different biological processes that are regulated by MYC, explaining why tumor-specific MYC levels induce specific gene expression programs and alter defined biological properties of cells. KW - MYC KW - promoter affinity KW - human KW - mathematical modeling KW - mouse KW - ChIP-sequencing KW - MIZ1 KW - cancer biology KW - cell biology KW - WDR5 Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-162913 VL - 5 ER -