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Sebastian Huss - One of the best experts on this subject based on the ideXlab platform.
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ss18 ssx fusion protein induced wnt β catenin signaling is a therapeutic target in Synovial Sarcoma
Oncogene, 2014Co-Authors: M Trautmann, Nicolaus Friedrichs, Elisabeth Sievers, Stefan Aretz, Dagmar Kindler, Sebastian Michels, Marcus Renner, Jutta Kirfel, S Steiner, Sebastian HussAbstract:Synovial Sarcoma is a high-grade soft tissue malignancy characterized by a specific reciprocal translocation t(X;18), which leads to the fusion of the SS18 (SYT) gene to one of three SSX genes (SSX1, SSX2 or SSX4). The resulting chimeric SS18-SSX protein is suggested to act as an oncogenic transcriptional regulator. Despite multimodal therapeutic approaches, metastatic disease is often lethal and the development of novel targeted therapeutic strategies is required. Several expression-profiling studies identified distinct gene expression signatures, implying a consistent role of Wnt/β-catenin signaling in Synovial Sarcoma tumorigenesis. Here we investigate the functional and therapeutic relevance of Wnt/β-catenin pathway activation in vitro and in vivo. Immunohistochemical analyses of nuclear β-catenin and Wnt downstream targets revealed activation of canonical Wnt signaling in a significant subset of 30 primary Synovial Sarcoma specimens. Functional aspects of Wnt signaling including dependence of Tcf/β-catenin complex activity on the SS18-SSX fusion proteins were analyzed. Efficient SS18-SSX-dependent activation of the Tcf/β-catenin transcriptional complex was confirmed by TOPflash reporter luciferase assays and immunoblotting. In five human Synovial Sarcoma Cell lines, inhibition of the Tcf/β-catenin protein–protein interaction significantly blocked the canonical Wnt/β-catenin signaling cascade, accompanied by the effective downregulation of Wnt targets (AXIN2, CDC25A, c-MYC, DKK1, CyclinD1 and Survivin) and the specific suppression of Cell viability associated with the induction of apoptosis. In SYO-1 Synovial Sarcoma xenografts, administration of small molecule Tcf/β-catenin complex inhibitors significantly reduced tumor growth, associated with diminished AXIN2 protein levels. In summary, SS18-SSX-induced Wnt/β-catenin signaling appears to be of crucial biological importance in Synovial Sarcoma tumorigenesis and progression, representing a potential molecular target for the development of novel therapeutic strategies.
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SS18-SSX fusion protein-induced Wnt/β-catenin signaling is a therapeutic target in Synovial Sarcoma
Oncogene, 2014Co-Authors: M Trautmann, Elisabeth Sievers, Stefan Aretz, Dagmar Kindler, Sebastian Michels, Marcus Renner, Jutta Kirfel, S Steiner, N Friedrichs, Sebastian HussAbstract:Synovial Sarcoma is a high-grade soft tissue malignancy characterized by a specific reciprocal translocation t(X;18), which leads to the fusion of the SS18 ( SYT ) gene to one of three SSX genes ( SSX1 , SSX2 or SSX4 ). The resulting chimeric SS18-SSX protein is suggested to act as an oncogenic transcriptional regulator. Despite multimodal therapeutic approaches, metastatic disease is often lethal and the development of novel targeted therapeutic strategies is required. Several expression-profiling studies identified distinct gene expression signatures, implying a consistent role of Wnt/β-catenin signaling in Synovial Sarcoma tumorigenesis. Here we investigate the functional and therapeutic relevance of Wnt/β-catenin pathway activation in vitro and in vivo . Immunohistochemical analyses of nuclear β-catenin and Wnt downstream targets revealed activation of canonical Wnt signaling in a significant subset of 30 primary Synovial Sarcoma specimens. Functional aspects of Wnt signaling including dependence of Tcf/β-catenin complex activity on the SS18-SSX fusion proteins were analyzed. Efficient SS18-SSX-dependent activation of the Tcf/β-catenin transcriptional complex was confirmed by TOPflash reporter luciferase assays and immunoblotting. In five human Synovial Sarcoma Cell lines, inhibition of the Tcf/β-catenin protein–protein interaction significantly blocked the canonical Wnt/β-catenin signaling cascade, accompanied by the effective downregulation of Wnt targets (AXIN2, CDC25A, c-MYC, DKK1, CyclinD1 and Survivin) and the specific suppression of Cell viability associated with the induction of apoptosis. In SYO-1 Synovial Sarcoma xenografts, administration of small molecule Tcf/β-catenin complex inhibitors significantly reduced tumor growth, associated with diminished AXIN2 protein levels. In summary, SS18-SSX-induced Wnt/β-catenin signaling appears to be of crucial biological importance in Synovial Sarcoma tumorigenesis and progression, representing a potential molecular target for the development of novel therapeutic strategies.
Mamoru Ouchida - One of the best experts on this subject based on the ideXlab platform.
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truncated ssx protein suppresses Synovial Sarcoma Cell proliferation by inhibiting the localization of ss18 ssx fusion protein
PLOS ONE, 2013Co-Authors: Yasushi Yoneda, Aki Yoshida, Yuki Morimoto, Kenji Shimizu, Toshiyuki Kunisada, Toshifumi Ozaki, Sachio Ito, Hirotaka Kanzaki, Mamoru OuchidaAbstract:Synovial Sarcoma is a relatively rare high-grade soft tissue Sarcoma that often develops in the limbs of young people and induces the lung and the lymph node metastasis resulting in poor prognosis. In patients with Synovial Sarcoma, specific chromosomal translocation of t(X; 18) (p11.2;q11.2) is observed, and SS18-SSX fusion protein expressed by this translocation is reported to be associated with pathogenesis. However, role of the fusion protein in the pathogenesis of Synovial Sarcoma has not yet been completely clarified. In this study, we focused on the localization patterns of SS18-SSX fusion protein. We constructed expression plasmids coding for the full length SS18-SSX, the truncated SS18 moiety (tSS18) and the truncated SSX moiety (tSSX) of SS18-SSX, tagged with fluorescent proteins. These plasmids were transfected in Synovial Sarcoma SYO-1 Cells and we observed the expression of these proteins using a fluorescence microscope. The SS18-SSX fusion protein showed a characteristic speckle pattern in the nucleus. However, when SS18-SSX was co-expressed with tSSX, localization of SS18-SSX changed from speckle patterns to the diffused pattern similar to the localization pattern of tSSX and SSX. Furthermore, Cell proliferation and colony formation of Synovial Sarcoma SYO-1 and YaFuSS Cells were suppressed by exogenous tSSX expression. Our results suggest that the characteristic speckle localization pattern of SS18-SSX is strongly involved in the tumorigenesis through the SSX moiety of the SS18-SSX fusion protein. These findings could be applied to further understand the pathogenic mechanisms, and towards the development of molecular targeting approach for Synovial Sarcoma.
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Frequent methylation of RASSF1A in Synovial Sarcoma and the anti-tumor effects of 5-aza-2′-deoxycytidine against Synovial Sarcoma Cell lines
Journal of Cancer Research and Clinical Oncology, 2010Co-Authors: Kunihiko Numoto, Aki Yoshida, Yuki Morimoto, Mamoru Ouchida, Toshiyuki Kunisada, Shinsuke Sugihara, Yasushi Yoneda, Yasuko Fujita, Keiichiro Nishida, Toshifumi OzakiAbstract:Purpose In this study, the methylation status of RASSF1A in Synovial Sarcomas and the effect of de-methylation on Synovial Sarcoma were examined. Methods The methylation status in 74 soft tissue Sarcomas (STSs) including 21 Synovial Sarcomas was determined by methylation specific PCR. The effect of the de-methylating agent 5-aza-2′-deoxycytidine (5-Aza-dC) on Synovial Sarcoma was examined using Synovial Sarcoma Cell lines (SYO-1 and HS-SY-II). Results RASSF1A methylation was observed in 10 (47.6%) of 21 Synovial Sarcomas and in 10 (18.9%) of 53 the other STSs ( P = 0.0295). De-methylation of the Cells by treatment with 5-Aza-dC induced re-expression of RASSF1A and growth suppression of the Cells. The calculated IC50 of 5-Aza-dC against the SYO-1 and the HS-SY-II Cells were 0.9 and 1.3 μM (96 h), respectively. With twice weekly administration of 1 or 10 mg/kg 5-Aza-dC, the growth of the mouse xenograft tumors of SYO-1 was significantly suppressed in comparison to the controls ( P
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frequent methylation of rassf1a in Synovial Sarcoma and the anti tumor effects of 5 aza 2 deoxycytidine against Synovial Sarcoma Cell lines
Journal of Cancer Research and Clinical Oncology, 2010Co-Authors: Kunihiko Numoto, Aki Yoshida, Yuki Morimoto, Mamoru Ouchida, Toshiyuki Kunisada, Shinsuke Sugihara, Yasushi Yoneda, Yasuko Fujita, Keiichiro Nishida, Toshifumi OzakiAbstract:Purpose In this study, the methylation status of RASSF1A in Synovial Sarcomas and the effect of de-methylation on Synovial Sarcoma were examined.
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establishment and characterization of a biphasic Synovial Sarcoma Cell line syo 1
Cancer Letters, 2004Co-Authors: Akira Kawai, Noriko Naito, Aki Yoshida, Yuki Morimoto, Mamoru Ouchida, Kenji Shimizu, Yasuo BeppuAbstract:We describe here the establishment of a new Synovial Sarcoma Cell line, SYO-1, derived from a biphasic Synovial Sarcoma that developed in the groin of a 19-year-old female. The Cell line was maintained for more than 70 passages (more than 24 months) in vitro. The SYO-1 Cells in monolayer culture exhibited a spindle shape without conspicuous pleomorphism. Immunohistochemically, the Cells were positive for vimentin, type IV collagen, S-100, mdm2, bcl-2, c-Met and c-Kit. Tumors developed by their implantation in nude mice histologically showed biphasic features that were composed of areas of fascicles of spindle Cells and areas of compact proliferation of polygonal to ovoid Cells, which occasionally formed epithelial plaque and expressed cytokeratin and EMA. SYO-1 Cells harbored the characteristic t(X;18)(p11.2;q11.2) translocation by chromosome analysis and SYT-SSX2 chimeric transcript by RT-PCR. The SYO-1 Cells, the first characterized Cell line derived from biphasic Synovial Sarcoma retaining the characteristic genetic and phenotypic features of the tumor, will be useful for various investigations on Synovial Sarcoma, especially for its epithelial differentiation.
Toshifumi Ozaki - One of the best experts on this subject based on the ideXlab platform.
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truncated ssx protein suppresses Synovial Sarcoma Cell proliferation by inhibiting the localization of ss18 ssx fusion protein
PLOS ONE, 2013Co-Authors: Yasushi Yoneda, Aki Yoshida, Yuki Morimoto, Kenji Shimizu, Toshiyuki Kunisada, Toshifumi Ozaki, Sachio Ito, Hirotaka Kanzaki, Mamoru OuchidaAbstract:Synovial Sarcoma is a relatively rare high-grade soft tissue Sarcoma that often develops in the limbs of young people and induces the lung and the lymph node metastasis resulting in poor prognosis. In patients with Synovial Sarcoma, specific chromosomal translocation of t(X; 18) (p11.2;q11.2) is observed, and SS18-SSX fusion protein expressed by this translocation is reported to be associated with pathogenesis. However, role of the fusion protein in the pathogenesis of Synovial Sarcoma has not yet been completely clarified. In this study, we focused on the localization patterns of SS18-SSX fusion protein. We constructed expression plasmids coding for the full length SS18-SSX, the truncated SS18 moiety (tSS18) and the truncated SSX moiety (tSSX) of SS18-SSX, tagged with fluorescent proteins. These plasmids were transfected in Synovial Sarcoma SYO-1 Cells and we observed the expression of these proteins using a fluorescence microscope. The SS18-SSX fusion protein showed a characteristic speckle pattern in the nucleus. However, when SS18-SSX was co-expressed with tSSX, localization of SS18-SSX changed from speckle patterns to the diffused pattern similar to the localization pattern of tSSX and SSX. Furthermore, Cell proliferation and colony formation of Synovial Sarcoma SYO-1 and YaFuSS Cells were suppressed by exogenous tSSX expression. Our results suggest that the characteristic speckle localization pattern of SS18-SSX is strongly involved in the tumorigenesis through the SSX moiety of the SS18-SSX fusion protein. These findings could be applied to further understand the pathogenic mechanisms, and towards the development of molecular targeting approach for Synovial Sarcoma.
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Frequent methylation of RASSF1A in Synovial Sarcoma and the anti-tumor effects of 5-aza-2′-deoxycytidine against Synovial Sarcoma Cell lines
Journal of Cancer Research and Clinical Oncology, 2010Co-Authors: Kunihiko Numoto, Aki Yoshida, Yuki Morimoto, Mamoru Ouchida, Toshiyuki Kunisada, Shinsuke Sugihara, Yasushi Yoneda, Yasuko Fujita, Keiichiro Nishida, Toshifumi OzakiAbstract:Purpose In this study, the methylation status of RASSF1A in Synovial Sarcomas and the effect of de-methylation on Synovial Sarcoma were examined. Methods The methylation status in 74 soft tissue Sarcomas (STSs) including 21 Synovial Sarcomas was determined by methylation specific PCR. The effect of the de-methylating agent 5-aza-2′-deoxycytidine (5-Aza-dC) on Synovial Sarcoma was examined using Synovial Sarcoma Cell lines (SYO-1 and HS-SY-II). Results RASSF1A methylation was observed in 10 (47.6%) of 21 Synovial Sarcomas and in 10 (18.9%) of 53 the other STSs ( P = 0.0295). De-methylation of the Cells by treatment with 5-Aza-dC induced re-expression of RASSF1A and growth suppression of the Cells. The calculated IC50 of 5-Aza-dC against the SYO-1 and the HS-SY-II Cells were 0.9 and 1.3 μM (96 h), respectively. With twice weekly administration of 1 or 10 mg/kg 5-Aza-dC, the growth of the mouse xenograft tumors of SYO-1 was significantly suppressed in comparison to the controls ( P
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frequent methylation of rassf1a in Synovial Sarcoma and the anti tumor effects of 5 aza 2 deoxycytidine against Synovial Sarcoma Cell lines
Journal of Cancer Research and Clinical Oncology, 2010Co-Authors: Kunihiko Numoto, Aki Yoshida, Yuki Morimoto, Mamoru Ouchida, Toshiyuki Kunisada, Shinsuke Sugihara, Yasushi Yoneda, Yasuko Fujita, Keiichiro Nishida, Toshifumi OzakiAbstract:Purpose In this study, the methylation status of RASSF1A in Synovial Sarcomas and the effect of de-methylation on Synovial Sarcoma were examined.
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growth suppression and apoptosis induction in Synovial Sarcoma Cell lines by a novel nf κb inhibitor dehydroxymethylepoxyquinomicin dhmeq
Cancer Letters, 2008Co-Authors: Keisuke Horiuchi, Akira Kawai, Hiroshi Sonobe, Hideo Morioka, Kazumasa Nishimoto, Yoshihisa Suzuki, Michiro Susa, Robert Nakayama, Hironari Takaishi, Toshifumi OzakiAbstract:Abstract Synovial Sarcoma is a relatively common soft tissue Sarcoma with an aggressive clinical course. Although surgery is currently the first treatment modality, improvement of adjuvant chemotherapy is deemed essential to improve the clinical outcome. Nuclear factor-κB (NF-κB) is constitutively activated in various cancer Cells and has emerged as a potential therapeutic molecular target; however, the possible involvement of NF-κB in the pathology of Sarcomas remains to be clarified. Herein we examined the effects of a novel NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ) on two Synovial Sarcoma-derived Cell lines, HS-SY-II and SYO-1. The growth of both Cell lines was completely inhibited by DHMEQ and apoptosis was induced at 10 μg/ml. Additionally, we found that DHMEQ showed additive effects when used in combination with other cytotoxic agents. These observations indicate that inhibition of NF-κB activity may serve as a potential therapeutic target for Synovial Sarcoma.
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photodynamic therapy with atx s10 na ii inhibits Synovial Sarcoma Cell growth
Clinical Orthopaedics and Related Research, 2008Co-Authors: Ken Takeda, Toshiyuki Kunisada, Shinichi Miyazawa, Yoshinori Nakae, Toshifumi OzakiAbstract:Photodynamic therapy (PDT) is an effective cancer treatment modality that allows selective destruction of malignant tumor Cells. We asked whether PDT could inhibit in vivo and in vitro growth of Synovial Sarcoma Cells. We analyzed PDT using ATX-S10·Na(II) and a diode laser for a Synovial Sarcoma Cell line (SYO-1). Photodynamic therapy with ATX-S10·Na(II) showed an in vitro cytotoxic effect on the cultured SYO-1 Cells. The in vitro effect of PDT depended on the treatment concentration of ATX-S10·Na(II) and the laser dose of irradiation. ATX-S10·Na(II) was detected in the tumor tissue specimens that were excised from nude mice bearing SYO-1 within 6 hours after intravenous injection, but it was eliminated from the tumor 12 hours after injection. Photodynamic therapy suppressed the tumor growth of nude mice bearing SYO-1, and high-dose irradiation induced no viable tumor Cells in histologic specimens. Photodynamic therapy performed after marginal resection of the tumor of nude mice bearing SYO-1 reduced the rate of local recurrence of the tumor. Our results suggest PDT using ATX-S10·Na(II) and laser irradiation may be a potentially useful treatment for Synovial Sarcoma, especially to reduce the surgical margin and preserve critical anatomic structures adjacent to the tumor.
Torsten O. Nielsen - One of the best experts on this subject based on the ideXlab platform.
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HDAC inhibition by quisinostat synergizes with proteasome inhibition to decrease Synovial Sarcoma Cell viability.
2017Co-Authors: Aimée N. Laporte, Jared J. Barrott, Ren Jie Yao, Neal M. Poulin, Bertha A. Brodin, Kevin B. Jones, Michael T. Underhill, Torsten O. NielsenAbstract:(A) In all Synovial Sarcoma Cell lines, but not HEK293T controls, the addition of 0.005 μM of bortezomib results in a downshift of approximately a full log of quisinostat, decreasing the amount of drug required to achieve the same effect as the HDAC inhibitor alone. (B) Isobologram analysis demonstrates synergy of these drug classes in Synovial Sarcoma Cell lines (but not HEK293T controls), as increasing concentration combinations fall below the additive isoboles. (C) Combination index (CI) values calculated for the combination of bortezomib and quisinostat in Synovial Sarcoma are significantly less than 1, indicating synergy of the compounds is occurring in all six Synovial Sarcoma Cell lines (but not HEK293T controls). Isobolograms and CI values were calculated using the Chou-Talalay-designed program CompuSyn. Statistical significance compared to vehicle treatment controls was determined by Student t test: * denotes p < 0.05; ** denotes p < 0.01; *** denotes p < 0.001. Error bars represent standard error of mean from conditions performed in triplicate.
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Quisinostat-mediated HDAC inhibition results in a dissociation of the driving complex in Synovial Sarcoma.
2017Co-Authors: Aimée N. Laporte, Jared J. Barrott, Ren Jie Yao, Neal M. Poulin, Bertha A. Brodin, Kevin B. Jones, Michael T. Underhill, Torsten O. NielsenAbstract:(A, B) Proximity ligation assay of SS18-SSX/TLE1 nuclear signal demonstrates a significant decrease in detectable protein co-localization following HDAC inhibition in SYO-1 Synovial Sarcoma Cells. (C) Quisinostat treatment at 0.025 μM reactivates targets of SS18-SSX-mediated gene repression, EGR1 and CDKN2A, in six human Synovial Sarcoma Cell lines. (D) Expression of EGR1, p16INKa and p14ARF (CDKN2A) protein levels increase with increasing concentrations of quisinostat, concomitant with a decrease in SS18-SSX protein levels. GAPDH was used as a loading control. Scale bars in panel A represent 20 μm. Statistical significance compared to vehicle treatment controls was determined by Student t test: * denotes p < 0.05. Error bars represent standard error of mean from conditions performed in triplicate.
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HDAC and Proteasome Inhibitors Synergize to Activate Pro-Apoptotic Factors in Synovial Sarcoma
2017Co-Authors: Aimée N. Laporte, Jared J. Barrott, Ren Jie Yao, Neal M. Poulin, Bertha A. Brodin, Kevin B. Jones, Michael T. Underhill, Torsten O. NielsenAbstract:Conventional cytotoxic therapies for Synovial Sarcoma provide limited benefit, and no drugs specifically targeting its driving SS18-SSX fusion oncoprotein are currently available. Patients remain at high risk for early and late metastasis. A high-throughput drug screen consisting of over 900 tool compounds and epigenetic modifiers, representing over 100 drug classes, was undertaken in a panel of Synovial Sarcoma Cell lines to uncover novel sensitizing agents and targetable pathways. Top scoring drug categories were found to be HDAC inhibitors and proteasomal targeting agents. We find that the HDAC inhibitor quisinostat disrupts the SS18-SSX driving protein complex, thereby reestablishing expression of EGR1 and CDKN2A tumor suppressors. In combination with proteasome inhibition, HDAC inhibitors synergize to decrease Cell viability and elicit apoptosis. Quisinostat inhibits aggresome formation in response to proteasome inhibition, and combination treatment leads to elevated endoplasmic reticulum stress, activation of pro-apoptotic effector proteins BIM and BIK, phosphorylation of BCL-2, increased levels of reactive oxygen species, and suppression of tumor growth in a murine model of Synovial Sarcoma. This study identifies and provides mechanistic support for a particular susceptibility of Synovial Sarcoma to the combination of quisinostat and proteasome inhibition.
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HDAC inhibition prevents aggresome formation in response to proteasome inhibitors, and combination treatment leads to endoplasmic reticulum stress.
2017Co-Authors: Aimée N. Laporte, Jared J. Barrott, Ren Jie Yao, Neal M. Poulin, Bertha A. Brodin, Kevin B. Jones, Michael T. Underhill, Torsten O. NielsenAbstract:(A) Knockdown of HDAC6 results in decreased levels of LC3B in the SYO-1 Synovial Sarcoma Cell line. (B) Proteasome inhibition as well as treatment with class I HDAC inhibitor romidepsin increases in LC3B levels, whereas quisinostat treatment decreases protein levels following treatment with proteasome inhibitors bortezomib or carfilzomib. (C) Aggresome formation is induced by bortezomib at 4 hours post treatment by PROTEOSTAT® staining analyzed by flow cytometry, an effect that is abrogated by quisinostat. The aggresome propensity factor (APF) is significantly decreased with the addition of quisinostat in the context of proteasome inhibition. (D) Endoplasmic reticulum stress markers are expressed following combination treatment and (E) a significant increase in ROS activity is measured by mean fluorescence intensity (MFI) of DCFDA, as compared with vehicle treated Cells. ROS activation is abrogated by N-acetylcysteine (N-AC) treatment at 10 mM. (F) Cell death is rescued with N-AC by ~50%. Statistical significance compared to vehicle treatment controls was determined by Student t test: * denotes p < 0.05. Error bars represent standard error of mean from conditions performed in triplicate. Vinculin or α-tubulin was used as a loading control for protein analysis.
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HDAC and proteasome inhibition leads to apoptosis via pro-apoptosis protein activation, ROS production and caspase activation.
2017Co-Authors: Aimée N. Laporte, Jared J. Barrott, Ren Jie Yao, Neal M. Poulin, Bertha A. Brodin, Kevin B. Jones, Michael T. Underhill, Torsten O. NielsenAbstract:(A) Pro-apoptotic proteins BIM and BIK are upregulated by both quisinostat and bortezomib, and the drug combination elicits phosphorylation of anti-apoptotic protein BCL-2 in SYO-1 Cells. (B) Cleavage of caspase 3 occurs following treatment with the drug combination in Synovial Sarcoma Cell lines, demonstrated by staining with IncuCyte™ Kinetic Caspase-3/7 Apoptosis Assay Reagent, (C) inducing significant apoptosis as confirmed by Annexin-V/PI staining in the SYO-1 Cell line (Q3: live, Q2: necrotic/late apoptotic, Q4: early apoptotic). (D) The low-dose quisinostat/bortezomib drug combination brings about a significant decrease in the viability of primary Synovial Sarcoma Cells (83-SS) as compared to matched normal muscle Cells derived from the same patient (83-muscle). Two-way ANOVA indicated a significant interaction between Cell type and response to the drug combination (p < 0.05). (E) Tumor growth in a murine model of Synovial Sarcoma was significantly reduced by day 21 with the quisinostat/bortezomib combination treatment, as compared to the vehicle only control. (F) Taken together, the combination of HDAC and proteasome inhibitors results in dissociation of the SS18-SSX driving complex as well as aggresome inhibition, ER stress and ROS production, leading to apoptosis induction in Synovial Sarcoma. Statistical significance compared to vehicle treatment controls was determined by Student t test or two-way ANOVA where indicated: * denotes p < 0.05. Error bars represent standard error of mean from conditions performed in triplicate. Vinculin was used as a loading control for protein analysis.
M Trautmann - One of the best experts on this subject based on the ideXlab platform.
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ss18 ssx fusion protein induced wnt β catenin signaling is a therapeutic target in Synovial Sarcoma
Oncogene, 2014Co-Authors: M Trautmann, Nicolaus Friedrichs, Elisabeth Sievers, Stefan Aretz, Dagmar Kindler, Sebastian Michels, Marcus Renner, Jutta Kirfel, S Steiner, Sebastian HussAbstract:Synovial Sarcoma is a high-grade soft tissue malignancy characterized by a specific reciprocal translocation t(X;18), which leads to the fusion of the SS18 (SYT) gene to one of three SSX genes (SSX1, SSX2 or SSX4). The resulting chimeric SS18-SSX protein is suggested to act as an oncogenic transcriptional regulator. Despite multimodal therapeutic approaches, metastatic disease is often lethal and the development of novel targeted therapeutic strategies is required. Several expression-profiling studies identified distinct gene expression signatures, implying a consistent role of Wnt/β-catenin signaling in Synovial Sarcoma tumorigenesis. Here we investigate the functional and therapeutic relevance of Wnt/β-catenin pathway activation in vitro and in vivo. Immunohistochemical analyses of nuclear β-catenin and Wnt downstream targets revealed activation of canonical Wnt signaling in a significant subset of 30 primary Synovial Sarcoma specimens. Functional aspects of Wnt signaling including dependence of Tcf/β-catenin complex activity on the SS18-SSX fusion proteins were analyzed. Efficient SS18-SSX-dependent activation of the Tcf/β-catenin transcriptional complex was confirmed by TOPflash reporter luciferase assays and immunoblotting. In five human Synovial Sarcoma Cell lines, inhibition of the Tcf/β-catenin protein–protein interaction significantly blocked the canonical Wnt/β-catenin signaling cascade, accompanied by the effective downregulation of Wnt targets (AXIN2, CDC25A, c-MYC, DKK1, CyclinD1 and Survivin) and the specific suppression of Cell viability associated with the induction of apoptosis. In SYO-1 Synovial Sarcoma xenografts, administration of small molecule Tcf/β-catenin complex inhibitors significantly reduced tumor growth, associated with diminished AXIN2 protein levels. In summary, SS18-SSX-induced Wnt/β-catenin signaling appears to be of crucial biological importance in Synovial Sarcoma tumorigenesis and progression, representing a potential molecular target for the development of novel therapeutic strategies.
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SS18-SSX fusion protein-induced Wnt/β-catenin signaling is a therapeutic target in Synovial Sarcoma
Oncogene, 2014Co-Authors: M Trautmann, Elisabeth Sievers, Stefan Aretz, Dagmar Kindler, Sebastian Michels, Marcus Renner, Jutta Kirfel, S Steiner, N Friedrichs, Sebastian HussAbstract:Synovial Sarcoma is a high-grade soft tissue malignancy characterized by a specific reciprocal translocation t(X;18), which leads to the fusion of the SS18 ( SYT ) gene to one of three SSX genes ( SSX1 , SSX2 or SSX4 ). The resulting chimeric SS18-SSX protein is suggested to act as an oncogenic transcriptional regulator. Despite multimodal therapeutic approaches, metastatic disease is often lethal and the development of novel targeted therapeutic strategies is required. Several expression-profiling studies identified distinct gene expression signatures, implying a consistent role of Wnt/β-catenin signaling in Synovial Sarcoma tumorigenesis. Here we investigate the functional and therapeutic relevance of Wnt/β-catenin pathway activation in vitro and in vivo . Immunohistochemical analyses of nuclear β-catenin and Wnt downstream targets revealed activation of canonical Wnt signaling in a significant subset of 30 primary Synovial Sarcoma specimens. Functional aspects of Wnt signaling including dependence of Tcf/β-catenin complex activity on the SS18-SSX fusion proteins were analyzed. Efficient SS18-SSX-dependent activation of the Tcf/β-catenin transcriptional complex was confirmed by TOPflash reporter luciferase assays and immunoblotting. In five human Synovial Sarcoma Cell lines, inhibition of the Tcf/β-catenin protein–protein interaction significantly blocked the canonical Wnt/β-catenin signaling cascade, accompanied by the effective downregulation of Wnt targets (AXIN2, CDC25A, c-MYC, DKK1, CyclinD1 and Survivin) and the specific suppression of Cell viability associated with the induction of apoptosis. In SYO-1 Synovial Sarcoma xenografts, administration of small molecule Tcf/β-catenin complex inhibitors significantly reduced tumor growth, associated with diminished AXIN2 protein levels. In summary, SS18-SSX-induced Wnt/β-catenin signaling appears to be of crucial biological importance in Synovial Sarcoma tumorigenesis and progression, representing a potential molecular target for the development of novel therapeutic strategies.
