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  • 1
    In: Cellular Oncology, Springer Science and Business Media LLC, Vol. 45, No. 3 ( 2022-06), p. 399-413
    Abstract: Synovial sarcoma (SySa) is a rare soft tissue tumor characterized by a reciprocal t(X;18) translocation. The chimeric SS18-SSX fusion protein represents the major driver of the disease, acting as aberrant transcriptional dysregulator. Oncogenic mechanisms whereby SS18-SSX mediates sarcomagenesis are incompletely understood, and strategies to selectively target SySa cells remain elusive. Based on results of Phospho-Kinase screening arrays, we here investigate the functional and therapeutic relevance of the transcription factor CREB in SySa tumorigenesis. Methods Immunohistochemistry of phosphorylated CREB and its downstream targets (Rb, Cyclin D1, PCNA, Bcl-xL and Bcl-2) was performed in a large cohort of SySa. Functional aspects of CREB activity, including SS18-SSX driven circuits involved in CREB activation, were analyzed in vitro employing five SySa cell lines and a mesenchymal stem cell model. CREB mediated transcriptional activity was modulated by RNAi-mediated knockdown and small molecule inhibitors (666-15, KG-501, NASTRp and Ro 31-8220). Anti-proliferative effects of the CREB inhibitor 666-15 were tested in SySa avian chorioallantoic membrane and murine xenograft models in vivo. Results We show that CREB is phosphorylated and activated in SySa, accompanied by downstream target expression. Human mesenchymal stem cells engineered to express SS18-SSX promote CREB expression and phosphorylation. Conversely, RNAi-mediated knockdown of SS18-SSX impairs CREB phosphorylation in SySa cells. Inhibition of CREB activity reduces downstream target expression, accompanied by suppression of SySa cell proliferation and induction of apoptosis in vitro and in vivo . Conclusion In conclusion, our data underline an essential role of CREB in SySa tumorigenesis and provides evidence for molecular targeted therapies.
    Type of Medium: Online Resource
    ISSN: 2211-3428 , 2211-3436
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2595105-1
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  • 2
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 79, No. 13_Supplement ( 2019-07-01), p. 2139-2139
    Abstract: Introduction: Soft tissue and bone tumors represent a heterogeneous group of neoplasias characterized by a wide variety of genetic aberrations. Albeit knowledge on tumorigenesis in mesenchymal tumors is continuously increasing, specific findings on altered signal transduction pathways as a basis for molecularly targeted therapeutic strategies is still sparse. Given recent studies on aberrant activation of the Hippo pathway transcriptional coactivators YAP and TAZ in different cancer types, the aim of this study was to determine the involvement of YAP/TAZ-mediated signal transduction in soft tissue and bone tumors. Experimental procedures: The expression levels of nuclear YAP and TAZ were analyzed by immunohistochemistry in a large cohort of 486 soft tissue and bone tumors. The comprehensive set of tissue specimens comprised 10 diagnostic categories: Angiosarcomas (AS; n=29), Ewing’s sarcomas (ES; n=20), leiomyosarcomas (LMS; n=68), malignant peripheral nerve sheath tumors (MPNST; n=45), solitary fibrous tumors (SFT; n=36), synovial sarcomas (SySa; n=65), well-differentiated liposarcomas (WDLS; n=55), dedifferentiated liposarcomas (DDLS; n=74), myxoid liposarcomas (MLS; n=85), and pleomorphic liposarcomas (PLS; n=9). The biological effects of the small molecule YAP/TAZ-TEAD inhibitor verteporfin on sarcoma cell proliferation (MPNST, SySa and MLS) were monitored by immunoblotting and cell viability assays in vitro. Results: Moderate to strong nuclear staining of YAP and TAZ was detected in 53% and 33% of soft tissue and bone tumor specimens, respectively. YAP nuclear expression was most prevalent in MPNST (58%), SySa (78%) and MLS (91%), whereas nuclear TAZ was predominately found in AS (55%), MLS (55%) and MPNST (71%). Immunoblotting confirmed the nuclear localization of YAP and TAZ in MPNST, SySa and MLS cell lines. Inhibition of the transcriptionally active YAP/TAZ-TEAD interaction employing the small molecular inhibitor verteporfin resulted in a significant suppression of sarcoma cell viability. Conclusions: This study identifies elevated transcriptional activity of nuclear YAP/TAZ as specific liability of subgroups of soft tissue and bone tumors. We provide preclinical evidence that YAP/TAZ-mediated signal transduction represents a rational target for therapeutic intervention in sarcoma cell lines that warrants further investigation. Citation Format: Ilka Isfort, Sandra Elges, Magdalene Cyra, Danielle Brandes, Ruth Berthold, Marcus Renner, Gunhild Mechtersheimer, Olle Larsson, Sebastian Huss, Eva Wardelmann, Wolfgang Hartmann, Marcel Trautmann. Hippo pathway transcriptional coactivators YAP/TAZ in soft tissue and bone tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2139.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2019
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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  • 3
    In: Scientific Reports, Springer Science and Business Media LLC, Vol. 9, No. 1 ( 2019-12-23)
    Abstract: Tumors of soft tissue and bone represent a heterogeneous group of neoplasias characterized by a wide variety of genetic aberrations. Albeit knowledge on tumorigenesis in mesenchymal tumors is continuously increasing, specific insights on altered signaling pathways as a basis for molecularly targeted therapeutic strategies are still sparse. The aim of this study was to determine the involvement of YAP1/TAZ-mediated signals in tumors of soft tissue and bone. Expression levels of YAP1 and TAZ were analyzed by immunohistochemistry in a large cohort of 486 tumor specimens, comprising angiosarcomas (AS), Ewing sarcomas, leiomyosarcomas, malignant peripheral nerve sheath tumors (MPNST), solitary fibrous tumors, synovial sarcomas (SySa), well-differentiated/dedifferentiated/pleomorphic and myxoid liposarcomas (MLS). Moderate to strong nuclear staining of YAP1 and TAZ was detected in 53% and 33%, respectively. YAP1 nuclear expression was most prevalent in MPNST, SySa and MLS, whereas nuclear TAZ was predominately detected in AS, MLS and MPNST. In a set of sarcoma cell lines, immunoblotting confirmed nuclear localization of YAP1 and TAZ, corresponding to their transcriptionally active pool. Suppression of YAP1/TAZ-TEAD mediated transcriptional activity significantly impaired sarcoma cell viability in vitro and in vivo . Our findings identify nuclear YAP1 and TAZ positivity as a common feature in subsets of sarcomas of soft tissue and bone and provide evidence of YAP1/TAZ-TEAD signaling as a specific liability to be considered as a new target for therapeutic intervention. Nuclear YAP1/TAZ expression may represent a biomarker suited to identify patients that could benefit from YAP1/TAZ-TEAD directed therapeutic approaches within future clinical trials.
    Type of Medium: Online Resource
    ISSN: 2045-2322
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2019
    detail.hit.zdb_id: 2615211-3
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