@article{SolimandoDaViaBollietal.2022,
  author    = {Solimando, Antonio Giovanni and Da Vi{\`a}, Matteo Claudio and Bolli, Niccol{\`o} and Steinbrunn, Torsten},
  title     = {The route of the malignant plasma cell in its survival niche: exploring "Multiple Myelomas"},
  series = {Cancers},
  volume    = {14},
  journal   = {Cancers},
  number    = {13},
  issn      = {2072-6694},
  doi       = {10.3390/cancers14133271},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-281728},
  year      = {2022},
  abstract  = {Growing evidence points to multiple myeloma (MM) and its stromal microenvironment using several mechanisms to subvert effective immune and anti-tumor responses. Recent advances have uncovered the tumor-stromal cell influence in regulating the immune-microenvironment and have envisioned targeting these suppressive pathways to improve therapeutic outcomes. Nevertheless, some subgroups of patients include those with particularly unfavorable prognoses. Biological stratification can be used to categorize patient-, disease- or therapy-related factors, or alternatively, these biological determinants can be included in a dynamic model that customizes a given treatment to a specific patient. Genetic heterogeneity and current knowledge enforce a systematic and comprehensive bench-to-bedside approach. Given the increasing role of cancer stem cells (CSCs) in better characterizing the pathogenesis of solid and hematological malignancies, disease relapse, and drug resistance, identifying and describing CSCs is of paramount importance in the management of MM. Even though the function of CSCs is well-known in other cancer types, their role in MM remains elusive. With this review, we aim to provide an update on MM homing and resilience in the bone marrow micro milieu. These data are particularly interesting for clinicians facing unmet medical needs while designing novel treatment approaches for MM.},
  language  = {en}
}
@article{WeissbachHerediaGuerreroBarnsteineretal.2020,
  author    = {Weißbach, Susann and Heredia-Guerrero, Sofia Catalina and Barnsteiner, Stefanie and Großhans, Lukas and Bodem, Jochen and Starz, Hanna and Langer, Christian and Appenzeller, Silke and Knop, Stefan and Steinbrunn, Torsten and Rost, Simone and Einsele, Hermann and Bargou, Ralf Christian and Rosenwald, Andreas and St{\"u}hmer, Thorsten and Leich, Ellen},
  title     = {Exon-4 Mutations in KRAS Affect MEK/ERK and PI3K/AKT Signaling in Human Multiple Myeloma Cell Lines},
  series = {Cancers},
  volume    = {12},
  journal   = {Cancers},
  number    = {2},
  issn      = {2072-6694},
  doi       = {10.3390/cancers12020455},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200617},
  year      = {2020},
  abstract  = {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.},
  language  = {en}
}
@article{KepplerWeissbachLangeretal.2016,
  author    = {Keppler, Sarah and Weißbach, Susann and Langer, Christian and Knop, Stefan and Pischimarov, Jordan and Kull, Miriam and St{\"u}hmer, Thorsten and Steinbrunn, Torsten and Bargou, Ralf and Einsele, Hermann and Rosenwald, Andreas and Leich, Ellen},
  title     = {Rare SNPs in receptor tyrosine kinases are negative outcome predictors in multiple myeloma},
  series = {Oncotarget},
  volume    = {7},
  journal   = {Oncotarget},
  number    = {25},
  doi       = {10.18632/oncotarget.9607},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177840},
  pages     = {38762-38774},
  year      = {2016},
  abstract  = {Multiple myeloma (MM) is a plasma cell disorder that is characterized by a great genetic heterogeneity. Recent next generation sequencing studies revealed an accumulation of tumor-associated mutations in receptor tyrosine kinases (RTKs) which may also contribute to the activation of survival pathways in MM. To investigate the clinical role of RTK-mutations in MM, we deep-sequenced the coding DNA-sequence of EGFR, EPHA2, ERBB3, IGF1R, NTRK1 and NTRK2 which were previously found to be mutated in MM, in 75 uniformly treated MM patients of the "Deutsche Studiengruppe Multiples Myelom". Subsequently, we correlated the detected mutations with common cytogenetic alterations and clinical parameters. We identified 11 novel non-synonymous SNVs or rare patient-specific SNPs, not listed in the SNP databases 1000 genomes and dbSNP, in 10 primary MM cases. The mutations predominantly affected the tyrosine-kinase and ligand-binding domains and no correlation with cytogenetic parameters was found. Interestingly, however, patients with RTK-mutations, specifically those with rare patient-specific SNPs, showed a significantly lower overall, event-free and progression-free survival. This indicates that RTK SNVs and rare patient-specific RTK SNPs are of prognostic relevance and suggests that MM patients with RTK-mutations could potentially profit from treatment with RTK-inhibitors.},
  language  = {en}
}
@article{SteinbrunnChatterjeeBargouetal.2014,
  author    = {Steinbrunn, Torsten and Chatterjee, Manik and Bargou, Ralf C. and St{\"u}hmer, Thorsten},
  title     = {Efficient Transient Transfection of Human Multiple Myeloma Cells by Electroporation - An Appraisal},
  series = {PLoS ONE},
  volume    = {9},
  journal   = {PLoS ONE},
  number    = {6},
  doi       = {10.1371/journal.pone.0097443},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119616},
  pages     = {e97443},
  year      = {2014},
  abstract  = {Cell lines represent the everyday workhorses for in vitro research on multiple myeloma (MM) and are regularly employed in all aspects of molecular and pharmacological investigations. Although loss-of-function studies using RNA interference in MM cell lines depend on successful knockdown, no well-established and widely applied protocol for efficient transient transfection has so far emerged. Here, we provide an appraisal of electroporation as a means to introduce either short-hairpin RNA expression vectors or synthesised siRNAs into MM cells. We found that electroporation using siRNAs was much more efficient than previously anticipated on the basis of transfection efficiencies deduced from EGFP-expression off protein expression vectors. Such knowledge can even confidently be exploited in "hard-to-transfect" MM cell lines to generate large numbers of transient knockdown phenotype MM cells. In addition, special attention was given to developing a protocol that provides easy implementation, good reproducibility and manageable experimental costs.},
  language  = {en}
}
@article{ChatterjeeAndrulisStuehmeretal.2013,
  author    = {Chatterjee, Manik and Andrulis, Mindaugas and St{\"u}hmer, Thorsten and M{\"u}ller, Elisabeth and Hofmann, Claudia and Steinbrunn, Torsten and Heimberger, Tanja and Schraud, Heike and Kressmann, Stefanie and Einsele, Hermann and Bargou, Ralf C.},
  title     = {The PI3K/Akt signaling pathway regulates the expression of Hsp70, which critically contributes to Hsp90-chaperone function and tumor cell survival in multiple myeloma},
  series = {Haematologica},
  volume    = {98},
  journal   = {Haematologica},
  number    = {7},
  doi       = {10.3324/haematol.2012.066175},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130574},
  pages     = {1132-1141},
  year      = {2013},
  abstract  = {Despite therapeutic advances multiple myeloma remains largely incurable, and novel therapeutic concepts are needed. The Hsp90-chaperone is a reasonable therapeutic target, because it maintains oncogenic signaling of multiple deregulated pathways. However, in contrast to promising pre-clinical results, only limited clinical efficacy has been achieved through pharmacological Hsp90 inhibition. Because Hsp70 has been described to interact functionally with the Hsp90-complex, we analyzed the suitability of Hsp72 and Hsp73 as potential additional target sites. Expression of Hsp72 and Hsp73 in myeloma cells was analyzed by immunohistochemical staining and western blotting. Short interfering RNA-mediated knockdown or pharmacological inhibition of Hsp72 and Hsp73 was performed to evaluate the role of these proteins in myeloma cell survival and for Hsp90-chaperone function. Furthermore, the role of PI3K-dependent signaling in constitutive and inducible Hsp70 expression was investigated using short interfering RNA-mediated and pharmacological PI3K inhibition. Hsp72 and Hsp73 were frequently overexpressed in multiple myeloma. Knockdown of Hsp72 and/or Hsp73 or treatment with VER-155008 induced apoptosis of myeloma cells. Hsp72/Hsp73 inhibition decreased protein levels of Hsp90-chaperone clients affecting multiple oncogenic signaling pathways, and acted synergistically with the Hsp90 inhibitor NVP-AUY922 in the induction of death of myeloma cells. Inhibition of the PI3K/Akt/GSK3b pathway with short interfering RNA or PI103 decreased expression of the heat shock transcription factor 1 and down-regulated constitutive and inducible Hsp70 expression. Treatment of myeloma cells with a combination of NVP-AUY922 and PI103 resulted in additive to synergistic cytotoxicity. In conclusion, Hsp72 and Hsp73 sustain Hsp90-haperone function and critically contribute to the survival of myeloma cells. Translation of Hsp70 inhibition into the clinic is therefore highly desirable. Treatment with PI3K inhibitors might represent an alternative therapeutic strategy to target Hsp70.},
  language  = {en}
}