Although adoptive cell therapy can be highly effective for the treatment of patients with melanoma, the application of this approach to the treatment of other solid tumors has been limited. The ...observation that the cancer germline (CG) antigen NY-ESO-1 is expressed in 70% to 80% and in approximately 25% of patients with synovial cell sarcoma and melanoma, respectively, prompted us to perform this first-in-man clinical trial using the adoptive transfer of autologous peripheral blood mononuclear cells that were retrovirally transduced with an NY-ESO-1-reactive T-cell receptor (TCR) to heavily pretreated patients bearing these metastatic cancers.
HLA-*0201 patients with metastatic synovial cell sarcoma or melanoma refractory to standard treatments and whose cancers expressed NY-ESO-1 received autologous TCR-transduced T cells following a lymphodepleting preparative chemotherapy. Response rates using Response Evaluation Criteria in Solid Tumors (RECIST), as well as immunologic correlates of response, are presented in this report.
Eleven of 18 patients with NY-ESO-1(+) synovial cell sarcomas (61%) and 11 of 20 patients with NY-ESO-1(+) melanomas (55%) who received autologous T cells transduced with an NY-ESO-1-reactive TCR demonstrated objective clinical responses. The estimated overall 3- and 5-year survival rates for patients with synovial cell sarcoma were 38% and 14%, respectively, whereas the corresponding estimated survival rates for patients with melanoma were both 33%.
The adoptive transfer of autologous T cells transduced with a retrovirus encoding a TCR against an HLA-A*0201 restricted NY-ESO-1 epitope can be an effective therapy for some patients bearing synovial cell sarcomas and melanomas that are refractory to other treatments.
Adoptive immunotherapy using tumor-infiltrating lymphocytes represents an effective cancer treatment for patients with metastatic melanoma. The NY-ESO-1 cancer/testis antigen, which is expressed in ...80% of patients with synovial cell sarcoma and approximately 25% of patients with melanoma and common epithelial tumors, represents an attractive target for immune-based therapies. The current trial was carried out to evaluate the ability of adoptively transferred autologous T cells transduced with a T-cell receptor (TCR) directed against NY-ESO-1 to mediate tumor regression in patients with metastatic melanoma and synovial cell sarcoma.
A clinical trial was performed in patients with metastatic melanoma or metastatic synovial cell sarcoma refractory to all standard treatments. Patients with NY-ESO-1-positive tumors were treated with autologous TCR-transduced T cells plus 720,000 iU/kg of interleukin-2 to tolerance after preparative chemotherapy. Objective clinical responses were evaluated using Response Evaluation Criteria in Solid Tumors (RECIST).
Objective clinical responses were observed in four of six patients with synovial cell sarcoma and five of 11 patients with melanoma bearing tumors expressing NY-ESO-1. Two of 11 patients with melanoma demonstrated complete regressions that persisted after 1 year. A partial response lasting 18 months was observed in one patient with synovial cell sarcoma.
These observations indicate that TCR-based gene therapies directed against NY-ESO-1 represent a new and effective therapeutic approach for patients with melanoma and synovial cell sarcoma. To our knowledge, this represents the first demonstration of the successful treatment of a nonmelanoma tumor using TCR-transduced T cells.
Oncogenesis in synovial sarcoma is driven by the chromosomal translocation t(X,18; p11,q11), which generates an in-frame fusion of the SWI/SNF subunit SS18 to the C-terminal repression domains of ...SSX1 or SSX2. Proteomic studies have identified an integral role of SS18-SSX in the SWI/SNF complex, and provide new evidence for mistargeting of polycomb repression in synovial sarcoma. Two recent in vivo studies are highlighted, providing additional support for the importance of WNT signaling in synovial sarcoma: One used a conditional mouse model in which knockout of β-catenin prevents tumor formation, and the other used a small-molecule inhibitor of β-catenin in xenograft models.
Synovial sarcoma appears to arise from still poorly characterized immature mesenchymal progenitor cells through the action of its primary oncogenic driver, the SS18-SSX fusion gene, which encodes a multifaceted disruptor of epigenetic control. The effects of SS18-SSX on polycomb-mediated gene repression and SWI/SNF chromatin remodeling have recently come into focus and may offer new insights into the basic function of these processes. A central role for deregulation of WNT-β-catenin signaling in synovial sarcoma has also been strengthened by recent in vivo studies. These new insights into the the biology of synovial sarcoma are guiding novel preclinical and clinical studies in this aggressive cancer.
Synovial sarcoma (SS) is defined by the hallmark SS18-SSX fusion oncoprotein, which renders BAF complexes aberrant in two manners: gain of SSX to the SS18 subunit and concomitant loss of BAF47 ...subunit assembly. Here we demonstrate that SS18-SSX globally hijacks BAF complexes on chromatin to activate an SS transcriptional signature that we define using primary tumors and cell lines. Specifically, SS18-SSX retargets BAF complexes from enhancers to broad polycomb domains to oppose PRC2-mediated repression and activate bivalent genes. Upon suppression of SS18-SSX, reassembly of BAF47 restores enhancer activation, but is not required for proliferative arrest. These results establish a global hijacking mechanism for SS18-SSX on chromatin, and define the distinct contributions of two concurrent BAF complex perturbations.
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•SS18-SSX assembly results in concurrent gains and losses in genome-wide BAF complex targeting•Synovial sarcoma is transcriptionally distinct from other BAF complex-driven malignancies•SS18-SSX targets BAF complexes to broad polycomb domains to activate bivalent genes•BAF47 reassembly activates enhancers but is dispensable for proliferative arrest
Incorporation of the synovial sarcoma SS18-SSX fusion into BAF complexes results in concomitant eviction of BAF47. McBride et al. show that SS18-SSX retargets BAF complexes from enhancers to polycomb domains to oppose PRC2-mediated repression. Reincorporation of BAF47 upon suppression of SS18-SSX restores enhancer activation but is not required for proliferative arrest.
Synovial sarcoma (SS) is a rare sarcoma driven by a translocation between SS18 and SSX 1, 2, or 4. With approximately 800 to 1,000 cases a year in the United States, it most commonly affects young ...adults between the ages of 15 and 30 years. The resultant tumors are either monophasic (pure sarcomas), biphasic (a combination or epithelioid and sarcomatous components), or poorly differentiated. The hybrid transcription factor SS18:SSX alters SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling and global methylation patterns that may allow for future therapeutic opportunities. In this review, we focus on the pharmacologic management of SS, both in the curative setting, where the standard approach is wide surgical excision combined with radiotherapy and/or (neo)adjuvant chemotherapy as appropriate, and in the palliative setting. In advanced disease, chemotherapy with anthracyclines and/or ifosfamide, trabectedin, or pazopanib has been demonstrated to be more active compared with other soft tissue sarcomas. In addition, a better understanding of the molecular and immunologic characteristics of SS has allowed for the identification of new potential targets and the development of novel biology-driven therapies that are all at different stages of testing. There include targeted agents, immunotherapy, and metabolic therapies. Because the impact of these strategies for improving SS outcome is still limited, current and future research is strongly needed to better understand the tumor biology, to identify predictive biomarkers, and to improve the outcomes for patients with SS.
A promising targeted therapy against NY-ESO-1 (CTAG 1B) using genetically modified T-cells in synovial sarcomas was recently demonstrated in a clinical trial at the NCI. To investigate the role of ...NY-ESO-1 immunohistochemistry in patient selection and gain better insight into the incidence of NY-ESO-1 expression in synovial sarcomas and other mesenchymal tumors, we evaluated NY-ESO-1 expression by immunohistochemistry in 417 tumors. This collection of samples included: 50 SS18/SSX1/2 fusion positive synovial sarcomas, 155 gastrointestinal stromal tumors (GIST), 135 other spindle cell sarcomas as well as 77 other sarcomas (chondrosarcoma, osteosarcoma, dedifferentiated liposarcoma, alveolar soft part sarcoma, rhabdomyosarcoma, angiosarcoma, malignant mesothelioma, and Ewing’s sarcoma). We report that 76% of synovial sarcomas expressed NY-ESO-1 in a strong and diffuse pattern (2−3+, >50–70% of tumor cells). In contrast, only rare cases of other spindle cell mesenchymal tumor expressed NY-ESO-1 (GIST (2/155), malignant peripheral nerve sheath tumors (1/34), and dermatofibrosarcoma protuberans (2/20)). Individual cases of other sarcomas (angiosarcoma, malignant mesothelioma, chondrosarcoma, osteosarcoma, dedifferentiated liposarcoma, alveolar soft part sarcoma, and Ewing’s sarcoma) were positive for NY-ESO-1. However, no positive cases were identified amongst our cohort of leiomyosarcomas (0/24), hemangiopericytoma/solitary fibrous tumors (0/40), and cellular schwannomas (0/17). In summary, we find that NY-ESO-1 is strongly and diffusely expressed in a majority of synovial sarcomas, but only rarely in other mesenchymal lesions. Beyond its role in patient selection for targeted therapy, immunohistochemistry for NY-ESO-1 may be diagnostically useful for the distinction of synovial sarcoma from other spindle cell neoplasms.
Abstract Synovial sarcoma (SS) is a malignant mesenchymal neoplasm with variable epithelial differentiation, with a propensity to occur in young adults and which can arise at almost any site. It is ...generally viewed and treated as a high-grade sarcoma. As one of the first sarcomas to be defined by the presence of a specific chromosomal translocation leading to the production of the SS18-SSX fusion oncogene, it is perhaps the archetypal “translocation-associated sarcoma,” and its translocation remains unique to this tumor type. Synovial sarcoma has a variety of morphologic patterns, but its chief forms are the classic biphasic pattern, of glandular or solid epithelial structures with monomorphic spindle cells and the monophasic pattern, of fascicles of spindle cells with only immunohistochemical or ultrastructural evidence of epithelial differentiation. However, there is significant morphologic heterogeneity and overlap with a variety of other neoplasms, which can cause diagnostic challenge, particularly as the immunoprofile is varied, SS18-SSX is not detected in 100% of SSs, and they may occur at unusual sites. Correct diagnosis is clinically important, due to the relative chemosensitivity of SS in relation to other sarcomas, for prognostication and because of the potential for treatment with specific targeted therapies in the near future. We review SS, with emphasis on the diagnostic spectrum, recent immunohistochemical and genetic findings, and the differential diagnosis.
Recent exon sequencing studies have revealed that over 20% of human tumors have mutations in subunits of mSWI/SNF (BAF) complexes. To investigate the underlying mechanism, we studied human synovial ...sarcoma (SS), in which transformation results from the translocation of exactly 78 amino acids of SSX to the SS18 subunit of BAF complexes. We demonstrate that the SS18-SSX fusion protein competes for assembly with wild-type SS18, forming an altered complex lacking the tumor suppressor BAF47 (hSNF5). The altered complex binds the Sox2 locus and reverses polycomb-mediated repression, resulting in Sox2 activation. Sox2 is uniformly expressed in SS tumors and is essential for proliferation. Increasing the concentration of wild-type SS18 leads to reassembly of wild-type complexes retargeted away from the Sox2 locus, polycomb-mediated repression of Sox2, and cessation of proliferation. This mechanism of transformation depends on only two amino acids of SSX, providing a potential foundation for therapeutic intervention.
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► SS18 is a dedicated and stable subunit of mSWI/SNF (BAF) complexes ► SS18-SSX fusion, the hallmark of synovial sarcomas, disrupts BAF complex composition ► SS18-SSX1 induces Sox2 expression, necessary for SS cell proliferation ► Synovial sarcoma cell proliferation is reversed via reassembly of normal complexes
SS18 is a subunit of the chromatin-remodeling complex BAF. In human synovial sarcoma, a genetic translocation produces an SS18-SSX fusion protein that competes with wild-type SS18, creating an altered BAF complex that activates—rather than suppresses—Sox2 and thus drives proliferation.
Summary Synovial sarcoma (SS) is regarded as a relatively chemosensitive sarcoma, but the prognosis of advanced SSs remains poor. Here we identified highly expressed cancer-testis antigens that could ...be promising immunotherapy targets for SS, using a previously conducted cDNA microarray, and we assessed the clinicopathological or prognostic relationships of these antigens in SS. We compared the gene expression profiles of 11 synovial sarcomas with those of three normal adipose tissues. Among the up-regulated cancer-testis antigens, we analyzed PRAME, MAGEA1 and MAGEA4 and another cancer-testis antigen (NY-ESO-1) together, by immunohistochemistry and real-time polymerase chain reaction (PCR) in 108 synovial sarcomas. Immunohistochemically, NY-ESO-1, PRAME, MAGEA4 and MAGEA1 were positive in 66/108 (61%), 93/108 (86%), 89/108 (82%) and 16/108 (15%) SSs, respectively, and 104/108 (96%) of the SSs showed the immunohistochemical expression of ≥ 1 of NY-ESO-1, PRAME and MAGEA4. Moreover, the high expression of ≥ 1 of these three antigens was observed in 83% of the SSs. High expression of NY-ESO-1 and MAGEA4 was significantly correlated with the presence of necrosis and advanced clinical stage. The immunohistochemical expression of these cancer-testis antigens was not correlated with prognosis, but the coexpression of NY-ESO-1, PRAME and MAGEA4 was significantly associated with adverse prognosis. The real-time PCR results were closely related to the immunohistochemical results: NY-ESO-1 (P = .0019), PRAME (P = .039), MAGEA4 (P = .0149), MAGEA1 (P = .0766). These data support the potential utility of NY-ESO-1, PRAME and MAGEA4 as immunotherapy targets and ancillary prognostic parameters, suggesting the possible benefit of the combined use of these cancer-testis antigens as an SS immunotherapy target.
Synovial sarcoma (SyS) is an aggressive neoplasm driven by the SS18-SSX fusion, and is characterized by low T cell infiltration. Here, we studied the cancer-immune interplay in SyS using an ...integrative approach that combines single-cell RNA sequencing (scRNA-seq), spatial profiling and genetic and pharmacological perturbations. scRNA-seq of 16,872 cells from 12 human SyS tumors uncovered a malignant subpopulation that marks immune-deprived niches in situ and is predictive of poor clinical outcomes in two independent cohorts. Functional analyses revealed that this malignant cell state is controlled by the SS18-SSX fusion, is repressed by cytokines secreted by macrophages and T cells, and can be synergistically targeted with a combination of HDAC and CDK4/CDK6 inhibitors. This drug combination enhanced malignant-cell immunogenicity in SyS models, leading to induced T cell reactivity and T cell-mediated killing. Our study provides a blueprint for investigating heterogeneity in fusion-driven malignancies and demonstrates an interplay between immune evasion and oncogenic processes that can be co-targeted in SyS and potentially in other malignancies.
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