In vitro anti-synovial sarcoma effect of diallyl trisulfide and mRNA profiling.

OBJECTIVE: Synovial sarcoma (SS) is a malignant soft tissue sarcoma and its natural history is a long, indolent clinical course followed by high rate of local recurrence and distant metastasis. Current therapies are still limited in increasing satisfactory of 5-year survival, especially for patients with recurrence and metastasis. Accordingly, finding new therapeutic drug for SS treatment is clinically urgent need. Diallyl trisulfide (DATS), a bioactive compound derived from garlic, is reported as a promising anti-cancer agent for various carcinomas. However, its effect on anti-SS remains unknown. This study investigated the anti-SS effect of DATS in human synovial sarcoma SW982 cells. METHODS: CCK-8 assay were used to examine the cell viability. High-content Imaging System was used to examine the apoptosis, intracellular ROS and autophagy. Flow cytometry was used to detect cell cycle. qPCR and Western blot were used to examine the expression of related mRNA and protein. High-throughput RNA-sequencing and bio-information analysis were used to investigate the mRNA profiling. RESULTS: The results showed a suppressive effect of DATS on tumor biology of SW982 cells including inducing apoptosis, triggering G2/M cell cycle arrest, elevating intracellular ROS and damaging mitochondria. Further high-throughput RNA-sequencing analysis clarified a comprehensive molecular portrait for DATS-induced transcriptional regulation. Besides, protein-protein interaction (PPI) analysis demonstrated that a network consisted of FOXM1, CCNA2, CCNB1, MYBL2, PLK1 and CDK1 might be response for DATS-induced G2/M cell cycle arrest and increased intracellular ROS. Notably, protein feature analysis revealed structure enrichment in microtubule network like kinesin motors domain, and tubulin domain. Molecular function analysis suggested that DATS-induced dysfunction of microtubule network might be the major cause for its effect on cell cycle arrest and successive apoptosis. Furthermore, 28 hub genes (including KIF2C, PLK1, CDK1, BIRC5, CCNB2, CENPF, TPX2, TOP2A and so on) were determined. Finally, pathway analysis showed that DATS-induced differentially expressed genes were mainly involved in cell cycle. CONCLUSION: Collectively, our findings for the first time provided the DATS-induced cellular response and transcriptional profiling of SW982 cells, which proposes that suppression of DATS on SS is multi-targeted and represent a therapeutic evidence for SS.

In silico and in vitro screening of small molecule Inhibitors against SYT-SSX1 fusion protein in synovial sarcoma.

Synovial sarcoma (SS) is characterized by a tumour specific chromosomal translocation t(X;18) (p11;q11) which results in the formation of SYT-SSX1 fusion protein. This fusion protein represents a clear therapeutic target and molecules specifically targeting SYT-SSX1 fusion protein are currently not available. In this study, SYT-SSX1 fusion protein sequence was retrieved from Uniprot and 3D structure was generated using I-TASSER modeling program. A structure based computational screening approach has been employed using Glide docking software to identify potential SYT-SSX1 small molecule inhibitors that bind to the junction region of the fusion protein. The obtained inhibitors were further filtered based on the docking score and ADME/T properties. Ten best fit compounds were chosen for in vitro studies. The anti-proliferative activities of these 10 compounds were screened in Yamato, ASKA (carries SYT-SSX1 fusion protein) and other sarcoma cell lines such as A673, 143B to understand the specificity of inhibition of the chosen compounds. The in vitro activity was compared against HEK293 cell lines. The compound 5-fluoro-3-(1-phenyl-1H-tetraazol-5-yl)-1H-indole (FPTI) was found to be selectively cytotoxic in synovial sarcoma cell lines (Yamato and ASKA) and this compound also showed insignificant anti proliferative activity on other cell lines. Further, target gene expression study confirmed that FPTI treatment down-regulated SYT-SSX1 and modulated its downstream target genes. Cell cycle analysis revealed the involvement of an apoptotic mechanism of cell death. Further experimental validations may elucidate the therapeutic potentials of FPTI against SYT-SSX1 fusion protein.

HMGB1-mediated autophagy decreases sensitivity to oxymatrine in SW982 human synovial sarcoma cells.

Oxymatrine (OMT) is a type of alkaloid extracted from a traditional Chinese medicinal herb, Sophora flavescens. Although the antitumor activities of OMT have been observed in various cancers, there are no reports regarding the effects of OMT on human synovial sarcoma. In the present study, we analyzed the antitumor activities of OMT in SW982 human synovial sarcoma cells and determine whether high mobility group box protein 1 (HMGB1)-mediated autophagy was associated with its therapeutic effects. We found that OMT exhibited antitumor activity in SW982 cells and facilitated increases in autophagy. Inhibition of autophagy by 3-MA or ATG7 siRNA increased the level of apoptosis, which indicated that OMT-induced autophagy protected cells from the cytotoxicity of OMT. Administration of OMT to SW982 cells increased the expression of HMGB1. When HMGB1 was inhibited via HMGB1-siRNA, OMT-induced autophagy was decreased, and apoptosis was increased. Furthermore, we found that HMGB1-siRNA significantly increased the expression of p-Akt and p-mTOR. OMT-induced autophagy may be mediated by the Akt/mTOR pathway, and HMGB1 plays a vital role in the regulation of autophagy. Therefore, we believe that combining OMT with an inhibitor of autophagy or HMGB1 may make OMT more effective in the treatment of human synovial sarcoma.

Pneumothorax as a complication of combination antiangiogenic therapy in children and young adults with refractory/recurrent solid tumors.

PURPOSE: Antiangiogenic agents show significant antitumor activity against various tumor types. In a study evaluating the combination of sorafenib, bevacizumab, and low-dose cyclophosphamide in children with solid tumors, an unexpectedly high incidence of pneumothorax was observed. We evaluated patient characteristics and risk factors for the development of pneumothorax in patients receiving this therapy. PATIENTS AND METHODS: Demographics, clinical course, and radiographic data of 44 patients treated with sorafenib, bevacizumab and cyclophosphamide were reviewed. Risk factors associated with the development of pneumothorax were analyzed. RESULTS: Pneumothorax likely related to study therapy developed in 11 of 44 (25%) patients of whom 33 had pulmonary abnormalities. Median age of patients was 14.7 years (range, 1.08-24.5). Histologies associated with pneumothorax included rhabdoid tumor, synovial sarcoma, osteosarcoma, Ewing sarcoma, Wilms tumor, and renal cell carcinoma. Cavitation of pulmonary nodules in response to therapy was associated with pneumothorax development (P<0.001). Median time from start of therapy to development of pneumothorax was 5.7 weeks (range, 2.4-31). CONCLUSION: The development of cavitary pulmonary nodules in response to therapy is a risk factor for pneumothorax. As pneumothorax is a potentially life-threatening complication of antiangiogenic therapy in children with solid tumors, its risk needs to be evaluated when considering this therapy.

Response to trabectedin in a patient with advanced synovial sarcoma with lung metastases.

Trabectedin is an alkylating agent registered in Europe for the treatment of advanced metastatic soft-tissue sarcomas, whose activity has been documented mainly in liposarcomas or leiomyosarcomas. Here, we report the response achieved in a patient with lung metastases from synovial sarcoma. A man with a large synovial sarcoma of the axilla underwent three cycles of neoadjuvant epirubicin+ifosfamide before complete excision, followed by three additional cycles of chemotherapy and radiotherapy. After 14 months, bilateral lung metastases appeared and were first treated with a prolonged 14-day continuous infusion of high-dose ifosfamide without response, and then with second-line trabectedin. A partial radiological response was achieved; dosage was reduced to 1.1 mg/m because of mild asthenia, grade 3 neutropenia, grade 3 nausea and vomiting, and reversible transaminase elevation. After 9 months of treatment, the lung nodules progressed, the patient received sorafenib, but further progressed and died 19 months after the first appearance of lung metastases. Trabectedin was the only drug that led to a radiological response in this patient with synovial sarcoma, despite being administered at 75% of the standard dose because of dose-limiting nausea and vomiting, in line with more recent data demonstrating activity in translocated sarcomas. We believe that trabectedin represents an attractive option for the treatment of metastatic synovial sarcoma and further clinical studies are warranted.

Emerging therapeutic targets for synovial sarcoma.

Synovial sarcoma is part of soft tissue sarcomas, an uncommon group of malignant tumors of mesenchymal origin. Unfortunately, a very limited number of useful drugs are active for most advanced synovial sarcoma. These tumors showed VEGF expression, and elevated serum VEGF levels correlate with higher histologic tumor grade. Inhibition of VEGFR was associated with tumor activity in preclinical models of synovial sarcoma and drugs such as sorafenib, pazopanib and bevacizumab have been employed in synovial sarcoma in monotherapy and in combination with chemotherapy. Other targets such as EGFR, HER2, IGFR-1R and mTOR have been exploited, but their inhibition by drugs such as gefitinib, trastuzumab, figitumumab, and temsirolimus, has not resulted in meaningful activity. Newer approaches include CXCR4 inhibition, immune-based therapies (NY-ESO-1), targeting epigenetic misregulation with HDAC inhibitors and targeting developmental pathways such Notch and Hedgehog. This review will summarize achievements and pitfalls of drugs against emerging therapeutic targets for synovial sarcoma.

PDGF receptor alpha is an alternative mediator of rapamycin-induced Akt activation: implications for combination targeted therapy of synovial sarcoma.

Akt activation by the IGF-1 receptor (IGF-1R) has been posited to be a mechanism of intrinsic resistance to mTORC1 inhibitors (rapalogues) for sarcomas. Here we show that rapamycin-induced phosphorylation of Akt can occur in an IGF-1R-independent manner. Analysis of synovial sarcoma cell lines showed that either IGF-1R or the PDGF receptor alpha (PDGFRA) can mediate intrinsic resistance to rapamycin. Repressing expression of PDGFRA or inhibiting its kinase activity in synovial sarcoma cells blocked rapamycin-induced phosphorylation of Akt and decreased tumor cell viability. Expression profiling of clinical tumor samples revealed that PDGFRA was the most highly expressed kinase gene among several sarcoma disease subtypes, suggesting that PDGFRA may be uniquely significant for synovial sarcomas. Tumor biopsy analyses from a synovial sarcoma patient treated with the mTORC1 inhibitor everolimus and PDGFRA inhibitor imatinib mesylate confirmed that this drug combination can impact both mTORC1 and Akt signals in vivo. Together, our findings define mechanistic variations in the intrinsic resistance of synovial sarcomas to rapamycin and suggest therapeutic strategies to address them.

Flavokawain B, a kava chalcone, induces apoptosis in synovial sarcoma cell lines.

Synovial sarcomas (SS) are soft tissue sarcomas with poor prognosis, displaying a lack of response to conventional cytotoxic chemotherapy. Although SS cell lines have moderate chemosensitivity to isofamide and doxorubicin therapy, the clinical prognosis is still poor. In this article, we showed that flavokawain B (FKB), a novel chalcone from kava extract, potently inhibits the growth of SS cell lines SYO-I and HS-SY-II through induction of apoptosis. Treatment with FKB increased caspase 8, 9, and 3/7 activity compared to vehicle-treated controls, indicating that both extrinsic and intrinsic apoptotic pathways were activated. Furthermore, FKB treatment of both cell lines resulted in increased mRNA and protein expression of death receptor-5 and the mitochondrial pro-apoptotic proteins Bim and Puma, while down-regulating the expression of an inhibitor of apoptosis, survivin in a dose-dependent manner. Our results suggest the natural compound FKB has a pro-apoptotic effect on SS cell lines. FKB may be a new chemotherapeutic strategy for patients with SS and deserves further investigation as a potential agent in the treatment of this malignancy.

Of mice and men: opportunities to use genetically engineered mouse models of synovial sarcoma for preclinical cancer therapeutic evaluation.

BACKGROUND: Synovial sarcoma is a soft tissue malignancy with a predilection for adolescents and young adults. Despite recent improvements in the understanding of its character and etiology, few therapeutic advances have been made. The mortality rate is high among the young population it affects. The low incidence of most subtypes of sarcoma, such as synovial sarcoma, makes disease-specific trials difficult to organize. The biological differences between sarcoma subtypes make inclusion of multiple types in general trials unsatisfactory as well. METHODS: A review of the literature regarding targetable pathways in synovial sarcoma was undertaken. A strategy has been devised to utilize available technologies in order to prioritize drug trial planning. RESULTS: Cell culture and xenograft research with synovial sarcoma cell lines have identified some critical pathways that may be targetable. Promising therapeutic strategies include newer cytotoxic chemotherapies, antiangiogenic agents, anti-IGF1R pathway agents, anti-Bcl-2/proapoptotic agents, and histone deacetylase complex inhibitors. CONCLUSIONS: We propose to prioritize potential therapeutic strategies via preclinical testing of agents in a genetic mouse model of synovial sarcoma. Preclinical optimization of treatment regimens can guide the development of more focused patient trials.

[Molecular pathology of sarcomas. Update on the research group "Molecular Diagnosis of Sarcomas"]. / Molekularpathologie von Sarkomen. Erste Ergebnisse des Sarkomforschungsverbundes KoSar.

To establish precise diagnostic algorithms and standardised treatment of sarcomas in specialized centers, the interdisciplinary research group KoSar (sarcoma competence network) has been funded by German Cancer Aid. A sarcoma tissue repository and a diagnostic reference center have been set up, presently containing about 1000 accurately diagnosed sarcomas of different entities. Significant gene expression profiles for synovial sarcomas, leiomyosarcomas, myxoid liposarcomas and a small profile for myxofibrosarcomas as well as a new classification of angiosarcomas were defined. We systematically searched for activated signal transduction pathways in sarcoma cell lines and xenograft transplant models and candidate targets for molecular therapies were identified. Based on these results first clinical studies have been initiated by the German Interdisciplinary Sarcoma Study Group (GISG).

Radiological assessment following thermoradiation therapy for primary pleural synovial sarcoma: case report.

Primary pleural synovial sarcoma is a rare disease with poor outcomes. Although hyperthermia therapy as part of a combined treatment regimen can offer improved local tumor control, only two reports of hyperthermia therapy for synovial sarcoma have appeared in the literature, and these sarcomas were not of pleuropulmonary origin. This report of an advanced inoperable primary pleural synovial sarcoma is the first to address the use of hyperthermia therapy in combination with chemoradiotherapy for this disease, together with radiological assessment following that therapy. Computed tomography performed after thermoradiation showed a decrease in tumor size and a characteristic unenhanced low-density area in the tumor suggesting that tumor necrosis resulted from the therapy. These image findings were helpful in assessing the tumor response to thermoradiation. We believe that hyperthermia therapy combined with chemoradiotherapy should be regarded as an option for advanced primary pleural synovial sarcoma. This would give computed tomography important role in evaluating this approach.

Preclinical analysis of tasidotin HCl in Ewing's sarcoma, rhabdomyosarcoma, synovial sarcoma, and osteosarcoma.

PURPOSE: Dolastatins are a group of structurally unique peptides originally isolated from a sea hare, Dolabella auricularia, which seem to inhibit tubulin polymerization and mitosis. Tasidotin hydrochloride (tasidotin), a novel synthetic analogue of dolastatin 15, is evaluated in preclinical models of pediatric tumors. EXPERIMENTAL DESIGN: The cytotoxicity of tasidotin was evaluated in a panel of pediatric sarcoma cell lines in vitro and in vivo. RESULTS: The IC(50) in Ewing's sarcoma, rhabdomyosarcoma, osteosarcoma, and synovial sarcoma lines ranged from 0.002 micro to 0.32 micromol/L. In the SK-ES1 and RH30 cell lines, tasidotin induced a G(2)-M arrest that persisted for 48 h after the drug was washed from the cells. In vitro, more than half the cells were in the early or late phase of apoptosis 48 h after treatment with tasidotin. In vivo, a significant increase in apoptotic nuclei was apparent in xenograft tumors harvested within 24 h after a 5-day course of tasidotin. In vivo response was determined in severe combined immunodeficient xenograft models of pediatric sarcomas implanted heterotopically. Significant antitumor activity was observed in all tumor lines tested. A complete response was observed in 2 synovial sarcoma lines, 1 osteosarcoma line, 1 rhabdomyosarcoma line, and 1 Ewing's sarcoma line. A partial response was observed in 1 rhabdomyosarcoma and 1 Ewing's sarcoma. CONCLUSIONS: Tasidotin induces a G(2)-M block in treated cells ultimately resulting in apoptosis. Antitumor activity is confirmed in vivo in preclinical xenograft models of pediatric sarcomas.

Ukrain treatment of a patient with retroperitoneal synovial sarcoma. Case report.

A 23-year-old woman, diagnosed with a synovial sarcoma of the peritoneum, underwent an operation for tumor extraction. In the postoperative period, Ukrain was injected i.v. at a dose of 10 mg on alternate days, for a total of 10 injections. After a 2-month break, this schedule was repeated. Ukrain treatment was well tolerated by the patient and there were no complications in the postoperative period. The following changes in immunohematological parameters were observed: increased total leucocytes, T lymphocytes and T helpers. Nearly 4 years after Ukrain therapy, the patient is in complete remission.

Tumor-induced hypercalcemia in a patient with extensive soft tissue sarcoma: effects of bisphosphonate therapy and surgery.

Tumor-induced hypercalcemia (TIH) is a frequent complication of advanced cancer, but it has been rarely reported in patients with sarcoma. We describe the case of a young female patient with TIH and with an extensive synoviosarcoma of the left lower limb destroying the bony structures. Hypercalcemia was severe (18.3 mg/dl) and accompanied by low serum Pi and suppressed parathyroid hormone (PTH) and 1,25(OH)2 vit D3 serum concentrations. Hypercalcemia was successfully treated with ibandronate, a new third-generation bisphosphonate, and radical surgery was performed when the patient was normocalcemic. Circulating levels of PTH-related protein (PTHrP) were elevated at 22.5 pmol/L (NI < 9). PTHrP levels did not change after successful therapy of TIH, in contrast with PTH, which increased sharply. PTHrP levels were normalized after radical surgery. Moreover, low serum Pi with reduced threshold for phosphate excretion and increased tubular calcium reabsorption supported the notion that PTHrP was indeed the essential mediator of paraneoplastic hypercalcemia in this case despite the extensive bone destruction.

Synovial sarcoma. Uniform response of metastases to high dose ifosfamide.

BACKGROUND: This report describes the unusually high response rate of metastatic synovial sarcoma to high dose ifosfamide (14-18 g/m2) when that drug was used to treat 13 consecutive patients with recurrent metastatic synovial sarcoma before surgery (or thoracotomies) to provide optimal salvage therapy for these patients. PATIENTS AND METHODS: Thirteen patients with recurrent or pulmonary metastatic synovial sarcoma seen at the Cedars-Sinai Comprehensive Cancer Center (Los Angeles, CA) from April, 1989 through January, 1993 were treated with high dose ifosfamide (14-18 g/m2). Ifosfamide was infused at the dose of 2 g/m2 over a 4-hour bolus infusion, followed by 2-g/m2 24-hour continuous infusions of ifosfamide, for a total of 14 or 18 g/m2 (6-8 days). Mesna (Mesnex, Bristol-Myers Oncology, Princeton, NJ) was infused with the ifosfamide at equimolar doses. Supplemental sodium bicarbonate (180 mEq) was given daily to prevent severe acidosis. Nine of the thirteen patients were treated with prior chemotherapy for their primary tumors. Prior chemotherapy consisted of doxorubicin (Adriamycin, Adria Labs, Dublin, OH) in all patients and doxorubicin combined with cisplatin in eight of them. RESULTS: All 13 patients had objective responses to high dose ifosfamide chemotherapy. There were nine partial responses and four complete responses. Five of the patients died of disease at 20-40 months (median, 27 months) from initial therapy. Eight patients have survived from 2 to 43 months (median, 20 months) from initial therapy, and three of these patients are disease free. Those patients surviving disease free had successful surgical removal of their residual metastatic disease after chemotherapy. CONCLUSION: Metastatic synovial sarcoma appears to be particularly sensitive to high dose ifosfamide chemotherapy. This experience suggests that there is a role for high dose ifosfamide chemotherapy in preoperative and postoperative adjuvant chemotherapy for primary synovial sarcoma, which is usually always a high grade malignant lesion with a poor prognosis after surgery alone.

Tetany due to hypomagnesemia induced by cisplatin and doxorubicin treatment for synovial sarcoma.

Hypocalcemic crisis developed in a patient with monophasic synovial sarcoma after amputation of the right leg, followed by long-term treatment with cisplatin and doxorubicin. Laboratory data revealed severe hypomagnesemia and hypocalcemia. High normal intact parathyroid hormone (PTH), elevated mid-region PTH and undetectable osteocalcin levels had already been found before the appearance of obvious symptoms concomitantly associated with moderate hypomagnesemia and hypocalcemia. Further, both PTH levels measured by two different methods gradually decreased until the initiation of magnesium supplementation. The magnesium supplement immediately relieved the tetany, and induced striking increases in both intact and mid-region PTH levels transiently and continuous elevations of osteocalcin levels. These results suggest that magnesium depletion has dual effects on PTH secretion, from stimulation to inhibition, as hypomagnesemia progresses. Both relative hypoparathyroidism and refractoriness of bone to PTH were thought to be responsible for hypocalcemia due to hypomagnesemia.

Oncogenic osteomalacia: imaging studies.

X-ray und NMR imaging studies of a 34-year-old patient with tumor-induced hypophosphatemic osteomalacia (OM) are presented. Besides typical features of OM, periosteal new bone formation was noticed initially. After 17 months of conservative treatment with supplements of inorganic phosphorus and 1,25-dihydroxyvitamin D, bone density had increased but Looser's zones were still present, while periosteal new bone formation was strikingly less evident. At this time a tumor in the first left metatarsal space became palpable, was surgically excised and proved to be a low-grade synovial sarcoma with hypervascular and partially calcified structures. Six months later an X-ray survey showed no more signs of metabolic osteopathy. Preoperatively, the pronounced vascularity of the tumor could be demonstrated by angiography and NMR scanning.

Differential response of retinoic acid pretreated human synovial sarcoma cell line to anticancer drugs.

The response of tumorigenic human synovial sarcoma (HSS) cell line to 10(-5)M optimum concentration of retinoic acid (RA) included changes in morphology, growth rate, suppression of anchorage-independent growth, induction of high alkaline phosphatase activity and excessive secretion of a 68 kDA glycoprotein of unknown function. HSS cells pretreated with 10(-5)M RA exhibited differential response to 3 potent anticancer drugs, namely cisplatin, vincristine and adriamycin. Sensitivity of the cells to cisplatin was found to be considerably enhanced after exposure to retinoic acid.