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  • American Society of Hematology  (37)
  • Bassermann, Florian  (37)
  • 1
    In: Blood, American Society of Hematology, Vol. 134, No. Supplement_1 ( 2019-11-13), p. 624-624
    Abstract: Achieving durable clinical responses to immune checkpoint inhibitors still remains a challenge. Here we demonstrate in preclinical models that immunotherapy with anti-CTLA-4 and its combination with anti-PD-1 rely on tumor cell-intrinsic activation of the cytosolic RNA receptor RIG-I (Fig. 1A). Mechanistically, tumor cell-intrinsic RIG-I signaling induced caspase-3-mediated tumor cell death, cross-presentation of tumor-associated antigen by CD103+ dendritic cells, subsequent expansion of tumor antigen-specific CD8+ T cells, and their accumulation within tumor tissue. Consistently, therapeutic targeting of RIG-I with 5'-triphosphorylated-RNA in both tumor and non-malignant host cells potently augmented the efficacy of CTLA-4 checkpoint blockade in several tumor models. In humans, transcriptome analysis of primary melanoma samples revealed a strong association between high expression of DDX58 (the gene encoding RIG-I), T cell receptor and antigen presentation pathway activity and prolonged overall survival (Fig. 1B). Moreover, in melanoma patients treated with anti-CTLA-4 checkpoint blockade, high RIG-I transcriptional activity significantly associated with durable clinical responses (Fig. 1C). Our preclinical data further demonstrate that tumor cell-intrinsic RIG-I signaling is also an essential pathway for the efficacy of other immunomodulating anticancer treatments including radiotherapy or hypomethylating agents such as 5-azacytidine. We thus identify aberrant tumor cell-intrinsic RIG-I signaling to be a crucial mechanism underlying cancer resistance to checkpoint inhibitor-based and other immunotherapies. These data have immediate translational potential as a RIG-I agonist for human application has been tested in phase I/II clinical trials with local administration in solid tumors and lymphomas (NCT03065023). Intratumoral RIG-I gene expression may not only serve as a biomarker to select patients that will likely benefit from anti-CTLA-4 therapy, but clinical RIG-I targeting in patients may also increase overall response rates of checkpoint inhibitor-based immunotherapy of malignancy including lymphoma. Figure 1. (A) Wild-type (WT) mice were bilaterally challenged with either WT or RIG-I-deficient (RIG-I-/-) B16.OVA melanoma cells.Recipients were repeatedly treated with anti-CTLA-4. Some mice were additionally injected with the RIG-I ligand 3pRNA into the right-sided tumor. Overall survival of treated mice bearing WT or RIG-I-/- B16.OVA tumors. (B) Overall survival in 456 TCGA melanoma patients by expression of DDX58 (RIG-I) in tumor samples. (C)DDX58 (RIG-I) expression in tumor samples from 18 patients with durable clinical response to anti-CTLA-4 treatment versus non-responders. Date give values from individual patients + geometric mean. Figure 1 Disclosures van den Brink: Seres Therapeutics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Flagship Ventures: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Evelo: Consultancy, Honoraria; Jazz Pharmaceuticals: Consultancy, Honoraria; Therakos: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Merck & Co, Inc.: Consultancy, Honoraria; Acute Leukemia Forum (ALF): Consultancy, Honoraria; Magenta and DKMS Medical Council: Membership on an entity's Board of Directors or advisory committees; Juno Therapeutics: Other: Licensing.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2019
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 2
    In: Blood, American Society of Hematology, Vol. 108, No. 11 ( 2006-11-16), p. 1118-1118
    Abstract: The regulated oscillation of protein expression is an essential mechanism of cell cycle control. The SCF class of E3 ubiquitin ligases is involved in this process by targeting cell cycle regulatory proteins for degradation by the proteasome, with the F-Box subunit of the SCF specifically recruiting a given substrate to the SCF core. We previously reported the cloning of NIPA (Nuclear Interaction Partner of ALK) in complex with constitutively active oncogenic fusions of ALK, which contributes to the development of lymphomas and sarcomas. Subsequently we characterized NIPA as a F-Box protein (FBP) that defines an oscillating ubiquitin E3 ligase targeting nuclear cyclin B1 in interphase thus contributing to the timing of mitotic entry. Using a conditional knockout strategy we inactivated the gene encoding the FBP NIPA to determined the consequences of NIPA deletion in vivo. The targeting construct was designed to flank exon 1 and 2 of the NIPA gene with loxP-sites. Deletion of this region was obtained by crossing the floxed mice to a cre-transgenic mouse strain expressing cre ubiquitously. NIPA deficiency did not affect the viability of NIPA −/− animals. Mating of heterozygotes yielded NIPA +/+, NIPA +/− and NIPA −/− offspring approximately at the expected Mendelian ratio. Although copulatory behavior was normal and vaginal plugs were produced, NIPA-deficient animals have a fertility defect. 100% of the tested NIPA −/− males and 60% of NIPA −/− females never produced progeny with young fertile wild-type mice. Interestingly, histological evaluation showed progressive testis atrophy in NIPA −/− males. Further analyses indicate a block in germ cell differentiation at the stage of meiotic prophase, no spermatides or spermatozoa were observed in NIPA-deficient animals. High levels of nuclear cyclin B1, a previously reported NIPA substrate, were present in NIPA-deficient germ cells. Furthermore, inactivation of NIPA leads to premature mitotic entry and subsequent mitotic catastrophe and TUNEL positive apoptosis in germ cells. Long-term studies of NIPA deficient mice may display a potential role of NIPA in tumor development. Since we found the most striking phenotype in high proliferating germ cells our results strongly confirm the cell cycle regulatory function of NIPA.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2006
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 3
    In: Blood, American Society of Hematology, Vol. 140, No. Supplement 1 ( 2022-11-15), p. 8711-8712
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2022
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 4
    In: Blood, American Society of Hematology, Vol. 124, No. 21 ( 2014-12-06), p. 177-177
    Abstract: Background Induction triplets with at least one of the “novel drugs” and steroids with or without chemotherapy are deemed standard of care in newly diagnosed multiple myeloma (MM). Medically fit patients (pts) remain candidates for subsequent autologous (auto) stem cell transplant (SCT) while the use of allogeneic (allo) SCT is an ongoing matter of debate. We had previously shown the RAD regimen to be well tolerated and highly effective in relapsed and relapsed/refractory disease. Based on the overall results we decided to further evaluate the combination in first-line treatment. Methods The current phase II trial was designed to include pts up to 65 years of age with newly diagnosed, symptomatic MM. Four 4-week RAD induction cycles (lenalidomide 25 mg/day, d 1-21; infusional adriamycin 9 mg/m², d1-4; oral dexamethasone 40 mg, d1-4 and 17-20; pegfilgrastim 6 mg, d 6) were followed by stem cell chemomobilization. Pts received either tandem auto SCT (melphalan 200 mg/m²; Mel) or auto followed by allo SCT. Allo SCT (conditioning regimen: treosulfan/fludarabine) was reserved for pts featuring at least one cytogenetic or serologic risk factor who had a matched sibling or unrelated donor available. Target dose for subsequent lenalidomide maintenance (R-maint; for one year) was 10 mg/d for tandem Mel and 5mg/d for auto/allo pts. Primary endpoint was response (at least VGPR) following second SCT. Results 190 pts with a median age of 55 (range, 30-66) years were recruited by 17 German centers between 8/2009 and 4/2012. 103 pts (56%) had ISS stage II/III disease and 165 pts are evaluable for molecular cytogenetic abnormalities assessed by fluorescence in situ hybridisation (FISH). Incidences were as follows: 29.6% had deletion of (del) chromosome 13q, 11.5% showed translocation (t) (4;14), 9% presented with del 17p, and 0.6% had a t(14;16). 163 pts completed all 4 RAD cycles and 47 underwent allogeneic SCT. 60 pts following tandem Mel and 15 pts after auto-allo SCT proceeded to R-maint. Median number of maintenance cycles was significantly higher in tandem Mel compared with auto-allo pts (12 versus 3; p=.01). Rate of at least (≥) VGPR increased from 47.9% following RAD induction to 60.6% following double SCT. Accordingly, post-induction complete response (CR)/stringent CR rate of 7.9% increased to 31%. In pts with FISH results, ≥ VGPR rate was 44% with t(4;14)/t(14;16)/del 17p versus 53% without those abnormalities, respectively (p=.34). Following double SCT, ≥ VGPR was increased to 63% [t(4;14)/t(14;16)/del 17 pts.] versus 65%, respectively (p=.84). Response was not different with either transplant strategy. No treatment-related mortality occurred during RAD induction, while non-relapse mortality at one year from allo SCT was 10.6%. Incidences of pneumonia, venous thromboembolism, and febrile neutropenia were 11, 7.2, and 5.3%, respectively. Preliminary overall survival results will be presented. Conclusions Our data show RAD induction to be very effective in newly diagnosed MM and to be well tolerated. By subsequent double SCT, a high number of CR/sCR was added. Correlative studies suggests response to be independent of known unfavourable cytogenetic prognosticators, such as t(4;14) and del 17p while time-to-event data will be needed to ultimately confirm a lenalidomide-based triple regimen being able to overcome adverse cytogenetic risk. Administration of R-maint to auto-allo pts was challenging despite a lenalidomide target dose of 5 mg/day. Disclosures Knop: Celgene GmbH: Consultancy, Honoraria. Off Label Use: Use of lenalidomide, doxorubicin, and dexamethasone in newly diagnosed multiple myeloma. Einsele:Celgene GmbH: Consultancy, Research Funding. Bargou:Amgen Inc.: Consultancy, Honoraria, Other.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2014
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 5
    In: Blood, American Society of Hematology, Vol. 124, No. 21 ( 2014-12-06), p. 648-648
    Abstract: Multiple myeloma (MM) is a plasma cell neoplasm characterized by the clonal expansion of an immunoglobulin-secreting terminally differentiated B cell. MM patients classically suffer from the triade consisting of plasma cell infiltration of the bone marrow, lytic bone lesions and monoclonal gammopathy in plasma and/or urine. During disease progress patients develop end organ damage such as nephropathy, neuropathy and bone marrow insufficiency. New treatment options including immunomodulatory drugs and proteasome inhibitors have prolonged overall survival and quality of life. However MM is still considered an incurable disease by conventional treatment approaches. Deregulated signal transduction pathways, in particular the Interleukin-6-JAK-STAT3 pathway, play an important role in the growth regulation and survival of MM cells. IL-6 binds to the specific IL-6 receptor and this complex associates with two molecules of the ubiquitously expressed common signal transducer gp130, which leads to JAK-STAT3 activation and STAT3 target expression. Using immunohistochemistry for STAT3 phosphorylation and by assessing gene expression data we have identified a recurrent STAT3 pathway activation pattern in approximately 40% of all MM patients, strongly indicating that deregulated gp130 downstream activation constitutes an attractive therapeutic target in MM. Based on these findings we generated a novel retroviral bone marrow transduction-transplantation MM mouse model using a constitutively active form of gp130, L-gp130. This L-gp130 mouse model shows all characteristics of the human disease, including monoclonal gammopathy, bone marrow infiltration with lytic bone lesions, and protein deposition in the kidney. Essentially, as compared to previous MM models, MM penetrance is very high and tumor latency with a median of approximately 200 days short. The disease is easily transplantable into secondary recipient mice. To assess clonality we subcloned and sequenced IgH rearrangements from individual tumors. Our analyses revealed that diseased mice contained monoclonal and oligoclonal B cell expansions, and also demonstrated a germinal center passage. Fluorescence in situ hybridization revealed the occurrence of Myc aberrations, a genetic feature that is associated with aggressive disease and short survival in human MM. A genetic in vivo approach revealed that gp130 signaling collaborates with Myc to induce MM, and that gp130 signaling is responsible and sufficient for directing the plasma cell phenotype and to dominantly regulate the expression of antiapoptotic proteins. Finally, testing of murine primary MM cells isolated from diseased L-gp130 animals with currently used anti-myeloma drugs such as bortezomib, carfilzomib, melphalan and doxorubicin revealed significant anti-tumor activity. In summary, the L-gp130 MM mouse model provides a novel tool with clinical and genetic features of human MM. It offers several clear advantages over existing murine MM models. Regarding the patient subgroup with a recurrent STAT3 pathway activation pattern it may serve as a genetic and preclinical tool for delineating MM pathogenesis, for evaluation of targeted therapies, and for assessment of in vivo treatment resistance. Disclosures Keller: Cellgene: Research Funding.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2014
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 6
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    American Society of Hematology ; 2008
    In:  Blood Vol. 112, No. 11 ( 2008-11-16), p. 5194-5194
    In: Blood, American Society of Hematology, Vol. 112, No. 11 ( 2008-11-16), p. 5194-5194
    Abstract: The ubiquitin-proteasome system plays a central role in the regulation of cell growth and cell proliferation by controlling the abundance of key cell cycle proteins. Increasing evidence indicates that unscheduled proteolysis of many cell cycle regulators contributes significantly to tumourigenesis and is indeed found in many types of human cancers, including colon and renal cell cancer, non hodgkin lymphomas, and multiple myelomas. Protein degradation pathways are also targets for cancer therapy, as shown by the successful introduction of bortezomib (B), an inhibitor of the 26S proteasome, for the therapy of multiple myeloma. Recently, protease inhibitors conventional in HIV therapy (e.g., ritonavir (R)) have been found to exert an antiproliferative effect on different tumor types, including multiple myeloma cells. More recently, ritonavir has been shown to induce endoplasmic reticulum stress and to sensitize sarcoma cells towards bortezomib induced apoptosis. In this study, we show that the combination of therapeutic concentrations of bortezomib and ritonavir acts synergistically on cultured multiple myeloma cell lines (U266, RPMI 8226, ARH-77 (2 variants-One is more resistant)). Cell proliferation was significantly reduced in an overadditive fashion as compared to individual treatments (proliferation as % of DMSO control after 48hrs: CRL-1621 (ARH-77): B: 40%, R: 50%, R & B: 7%, CCL-155 (RPMI 8226): B: 37%, R: 50%, B+R: 6%; n=3). Moreover, we found proteasome inhibition by bortezomib to be associated with low levels of expression of Skp2 and consequent stabilization of its target p27Kip1, a negative cell cycle regulator at the G1/S cell cycle transition. Accordingly, bortezomib induced cell cycle arrest at the G1/S transition followed by caspase dependent apoptosis. In contrast, only mild induction of apoptosis and no activation of Caspase 3 were observed in myeloma cells treated with ritonavir, although growth arrest was present. Interestingly, growth arrest in ritonavir-treated cells was associated with an accumulation in G2 phase. In a limited clinical study, we treated two patients with stage III relapsed and refractory myeloma with a combination of bortezomib at standard doses and ritonavir at 600 mg twice a day. Both patients had MR or greater lasting for more than 2 months. Only grade 2 GI toxicity was seen. Taken together, our findings suggest different mechanisms of action for bortezomib and ritonavir on myeloma cells and suggest that the combination of the two drugs may be a valid therapeutic strategy.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2008
    detail.hit.zdb_id: 1468538-3
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  • 7
    In: Blood, American Society of Hematology, Vol. 140, No. Supplement 1 ( 2022-11-15), p. 7619-7621
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2022
    detail.hit.zdb_id: 1468538-3
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  • 8
    In: Blood, American Society of Hematology, Vol. 140, No. Supplement 1 ( 2022-11-15), p. 2906-2907
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2022
    detail.hit.zdb_id: 1468538-3
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  • 9
    In: Blood, American Society of Hematology, Vol. 137, No. 2 ( 2021-01-14), p. 155-167
    Abstract: The histone mark H3K27me3 and its reader/writer polycomb repressive complex 2 (PRC2) mediate widespread transcriptional repression in stem and progenitor cells. Mechanisms that regulate this activity are critical for hematopoietic development but are poorly understood. Here we show that the E3 ubiquitin ligase F-box only protein 11 (FBXO11) relieves PRC2-mediated repression during erythroid maturation by targeting its newly identified substrate bromo adjacent homology domain–containing 1 (BAHD1), an H3K27me3 reader that recruits transcriptional corepressors. Erythroblasts lacking FBXO11 are developmentally delayed, with reduced expression of maturation-associated genes, most of which harbor bivalent histone marks at their promoters. In FBXO11−/− erythroblasts, these gene promoters bind BAHD1 and fail to recruit the erythroid transcription factor GATA1. The BAHD1 complex interacts physically with PRC2, and depletion of either component restores FBXO11-deficient erythroid gene expression. Our studies identify BAHD1 as a novel effector of PRC2-mediated repression and reveal how a single E3 ubiquitin ligase eliminates PRC2 repression at many developmentally poised bivalent genes during erythropoiesis.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2021
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 10
    In: Blood, American Society of Hematology, Vol. 134, No. Supplement_1 ( 2019-11-13), p. 314-314
    Abstract: Introduction: Cereblon (CRBN) is the target for immunomodulatory drugs (IMiDs) such as thalidomide and its derivatives lenalidomide and pomalidomide, which are key therapeutics for hematologic malignancies such as multiple myeloma (MM) and del(5q) myelodysplastic syndrome (MDS). We have previously described a ubiquitin-independent chaperone-like function of CRBN, which stabilizes the transmembrane proteins CD147 and MCT1. IMiDs interfere with this chaperone-like function of CRBN in a competitive manner to mediate both their anti-tumor and their teratotoxic effects (Eichner et al. Nature Medicine 2016). So far, the underlying mechanisms of transmembrane protein maturation, the global impact of CRBN on the cell surface proteome and the precise molecular mechanism of IMiDs, especially their clinically well-established synergy with proteasomal inhibitors remain unclear. Methods: Novel CRBN-clients were identified by cross-validation of the CRBN-interactome with a cell surface proteomic screen. Various molecular and cell biological methods including immunofluorescence, flow cytometry, immunoprecipitations, GST-pulldowns, amino acid transport and proliferation assays were used to decipher underlying mechanisms. In vitro assays and in vivo xenograft experiments were performed using MM cell lines and patient-derived CD138+ MM cells. 18FDG- and 18FET-PET was used for imaging of xenografted tumors. Results: Our unbiased screening approaches imply a global role of CRBN in transmembrane protein maturation. In particular, we identify the amino acid transporter LAT1 and its functional subunit CD98hc as novel CRBN client proteins, which are frequently overexpressed in MM to drive cell proliferation. CD98hc/LAT1 become destabilized and inactivated upon IMiD treatment, which attenuates MM cell proliferation, tumor formation and perturbs the uptake of essential amino acids, thereby further linking IMiD-activity to tumor-metabolism. CD98hc/LAT1 destabilization only occurs in IMiD-sensitive patients and cell lines, thus being a potential biomarker to predict IMiD-response. Moreover, inhibition of LAT1 is cytotoxic in both IMiD-sensitive and -resistant cells, which makes it an attractive therapeutic option for IMiD-resistant and -refractory patients. Mechanistically, we show CRBN to function as a new selective co-chaperone of HSP90, which facilitates transmembrane protein maturation in a ubiquitin-independent way, which is impaired by IMiD-treatment. Conclusion: We establish CRBN as a transmembrane protein-specific co-chaperone for HSP90 and identify modulation of the CRBN-CD98hc/LAT1 axis as crucial means by which IMiDs mediate their anti-tumor activity. Notably, we specify CD98hc/LAT1 as valuable biomarkers for IMiD-response and druggable targets for IMiD-resistant and -refractory MM patients and beyond. Furthermore, this ubiquitin-independent mechanism solves the paradox regarding the well documented synergistic anti-myeloma activity of IMiDs and proteasomal inhibitors. Disclosures Götze: AbbVie: Membership on an entity's Board of Directors or advisory committees. Bassermann:Celgene: Consultancy, Research Funding.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2019
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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