Search

Secreted protein acidic and rich in cysteine (SPARC) is a matricellular glycoprotein overexpressed by several cancers. Because SPARC shows high binding affinity to albumin, we reasoned that pediatric sarcoma xenografts expressing SPARC would show enhanced uptake and accumulation of nanoparticle albumin-bound (nab)-paclitaxel, a potent anticancer drug formulation. We first evaluated the expression of SPARC in patient-derived xenografts (PDXs) of Ewing sarcoma, rhabdomyosarcoma and osteosarcoma, finding variable SPARC gene expression that correlated well with SPARC protein measured by immunoblotting. We revealed that the activity of the fusion gene chimera EWSR1-FLI1, the genetic driver of Ewing sarcoma, leads to lower expression of the gene SPARC in these tumors, likely due to enriched acetylation marks of the histone H3 lysine 27 at regions including the SPARC promoter and potential enhancers. Then, we used SPARC-edited Ewing sarcoma cells (A673 line) to demonstrate that SPARC knocked down (KD) cells accumulated significantly less amount of nab-paclitaxel in vitro than SPARC wild type (WT) cells. In vivo, SPARC KD and SPARC WT subcutaneous xenografts in mice achieved similar maximum intratumoral concentrations of nab-paclitaxel, though drug clearance from SPARC WT tumors was significantly slower. We confirmed such SPARC-mediated long-term intratumoral accumulation of nab-paclitaxel in Ewing sarcoma PDX with high expression of SPARC, which accumulated significantly more nab-paclitaxel than SPARC-low PDX. SPARC-high PDX responded better to nab-paclitaxel than SPARC-low tumors, although these results should be taken cautiously, given that the PDXs were established from different patients that could have specific determinants predisposing response to paclitaxel. In addition, SPARC KD Ewing sarcoma xenografts responded better to soluble docetaxel and paclitaxel than to nab-paclitaxel, while SPARC WT ones showed similar response to soluble and albumin-carried drugs. Overall, our results show that pediatric sarcomas expressing SPARC accumulate nab-paclitaxel for longer periods of time, which could have clinical implications for chemotherapy efficacy., AMC acknowledges funding from AECC Scientific Foundation, MINECO (SAF2011-22660), European Union Seventh Framework Programme (FP7/2007-2013) under Marie Curie International Reintegration Grant (PIRG-08-GA-2010-276998) and ISCIII-FEDER (CP13/00189 and CPII18/00009). EDA, OMT and JM acknowledge support of AECC Scientific Foundation (GCB13131578). NU acknowledges funding by the Basque Government, Research Groups of the Basque University System (Project No. IT 1186-19). We thank support of the Central Service of Analysis in Alava, SGIker (UPV/EHU/ERDF, EU) and Xarxa de Bancs de Tumors de Catalunya (XBTC) sponsored by Pla Director d'Oncologia de Catalunya.

Supplementary Figures S1-S5. MDM4 modulation by HEY1 occurs downstream of TP53 (S1); Modulation of SIRT1 and TP53 induction upon ectopic expression of Flag-tagged HEY1 in the B-cell malignancy cell lines "697" and NALM6, and in primary keratinocytes (S2); The degree of SIRT1 modulation depends on HEY1 levels (S3); Flow-diagram of samples analysed on tissue micro arrays (TMA1, TMA2, TMA3), and FFPE sections used in this study (S4); Kaplan-Meier survival estimates for patients analysed for SIRT1 expression on TMA3 (S5).

Supplementary Table 2 from Caveolin-1 (CAV1) Is a Target of EWS/FLI-1 and a Key Determinant of the Oncogenic Phenotype and Tumorigenicity of Ewing's Sarcoma Cells

PDF file - 180K

Supplementary Tables S1-S4. Identification of HEY1 regulated genes downstream of EWS-FLI1 silencing in Ewing sarcoma (S1); Combined immunohistochemical staining results for samples from patients with metastases at diagnosis on TMA1 and 2 according to site of metastasis (S2); Clinical characteristics and SIRT1 staining results of primary tumors from 43 ES patients treated at St. Jude Children´s Hospital between 1979 and 1987 using vincristine, doxorubicin, and cyclophosphamide-based regimens, with subsequent addition of ifosfamide and etoposide (S3); Materials used in the study (S4).

Supplementary Table 1 from Caveolin-1 (CAV1) Is a Target of EWS/FLI-1 and a Key Determinant of the Oncogenic Phenotype and Tumorigenicity of Ewing's Sarcoma Cells

Tumors of the Ewing's sarcoma family (ESFT), such as Ewing's sarcoma (EWS) and primitive neuroectodermal tumors (PNET), are highly aggressive malignancies predominantly affecting children and young adults. ESFT express chimeric transcription factors encoded by hybrid genes fusing the EWS gene with several ETS genes, most commonly FLI-1. EWS/FLI-1 proteins are responsible for the malignant phenotype of ESFT, but only few of their transcriptional targets are known. Using antisense and short hairpin RNA–mediated gene expression knockdown, array analyses, chromatin immunoprecipitation methods, and reexpression studies, we show that caveolin-1 (CAV1) is a new direct target of EWS/FLI-1 that is overexpressed in ESFT cell lines and tumor specimens and is necessary for ESFT tumorigenesis. CAV1 knockdown led to up-regulation of Snail and the concomitant loss of E-cadherin expression. Consistently, loss of CAV1 expression inhibited the anchorage-independent growth of EWS cells and markedly reduced the growth of EWS cell–derived tumors in nude mice xenografts, indicating that CAV1 promotes the malignant phenotype in EWS carcinogenesis. Reexpression of CAV1 or E-cadherin in CAV1 knockdown EWS cells rescued the oncogenic phenotype of the original EWS cells, showing that the CAV1/Snail/E-cadherin pathway plays a central role in the expression of the oncogenic transformation functions of EWS/FLI-1. Overall, these data identify CAV1 as a key determinant of the tumorigenicity of ESFT and imply that targeting CAV1 may allow the development of new molecular therapeutic strategies for ESFT patients. (Cancer Res 2006; 66(20): 9937-47)

Protein kinases represent promising anticancer drug targets. We describe here the meriolins, a new family of inhibitors of cyclin-dependent kinases (CDK). Meriolins represent a chemical structural hybrid between meridianins and variolins, two families of kinase inhibitors extracted from various marine invertebrates. Variolin B is currently in preclinical evaluation as an antitumor agent. A selectivity study done on 32 kinases showed that, compared with variolin B, meriolins display enhanced specificity toward CDKs, with marked potency on CDK2 and CDK9. The structures of pCDK2/cyclin A/variolin B and pCDK2/cyclin A/meriolin 3 complexes reveal that the two inhibitors bind within the ATP binding site of the kinase, but in different orientations. Meriolins display better antiproliferative and proapoptotic properties in human tumor cell cultures than their parent molecules, meridianins and variolins. Phosphorylation at CDK1, CDK4, and CDK9 sites on, respectively, protein phosphatase 1α, retinoblastoma protein, and RNA polymerase II is inhibited in neuroblastoma SH-SY5Y cells exposed to meriolins. Apoptosis triggered by meriolins is accompanied by rapid Mcl-1 down-regulation, cytochrome c release, and activation of caspases. Meriolin 3 potently inhibits tumor growth in two mouse xenograft cancer models, namely, Ewing's sarcoma and LS174T colorectal carcinoma. Meriolins thus constitute a new CDK inhibitory scaffold, with promising antitumor activity, derived from molecules initially isolated from marine organisms. [Cancer Res 2007;67(17):8325–34]

Supplementary Figure 4 from Meriolins, a New Class of Cell Death–Inducing Kinase Inhibitors with Enhanced Selectivity for Cyclin-Dependent Kinases

PDF file - 78K

Supplementary Figures 1-4 from Caveolin-1 (CAV1) Is a Target of EWS/FLI-1 and a Key Determinant of the Oncogenic Phenotype and Tumorigenicity of Ewing's Sarcoma Cells

Supplementary Materials and Figures 1-3 from PCPH/ENTPD5 Expression Confers to Prostate Cancer Cells Resistance against Cisplatin-Induced Apoptosis through Protein Kinase Cα–Mediated Bcl-2 Stabilization

Supplementary Figure Legends. Legend for Supplementary Figures S1-S5.

Methods and Materials, Figure 4 Legend from Meriolins, a New Class of Cell Death–Inducing Kinase Inhibitors with Enhanced Selectivity for Cyclin-Dependent Kinases

Supplementary Methods, Figure and Table Legends from Caveolin-1 (CAV1) Is a Target of EWS/FLI-1 and a Key Determinant of the Oncogenic Phenotype and Tumorigenicity of Ewing's Sarcoma Cells

Background: Rhabdomyosarcoma (RMS) is the most prevalent soft tissue sarcoma in children and adolescents. It is divided in two major histological subtypes, being the Alveolar (ARMS) the one associated to a poorer prognosis1. The cure rate for these tumors is up to 70% for children with localized disease, but this numbers decrease notably to a 20% 5-year survival rate for patients that show metastatic spreading. However, mechanisms leading to metastatic disease remain poorly understood. Hence, there is an urgent need to better understand this process, which will hopefully lead to novel targeted therapies and improved survival rates for these patients. Methods: ARMS cells (RH4) were injected in the gastrocnemius muscle of Athymic Nude-Foxn1nu mice2. Primary tumors (800mm3) and peritoneal metastases (visible by IVIS®) were collected, and RNA extracted. Xenograft-derived metastatic cell lines were obtained directly as a primary culture from mice metastases. Characterization of paired tumors and metastases was performed using Clariom™ D microarray (Applied Biosystems). After data normalization and comparative analyses (R; RMA and limma), a list of differentially expressed transcripts between sample groups was obtained. These are being validated by qPCR and Western Blot. Results: Transcriptomic profiling of tumors (n=3), paired metastases (n=3), xenograft-derived metastatic cell lines (n=3) and RH4 cell line (n=3) revealed 3420 differentially expressed transcripts (2747 increased in metastases, 673 in tumors). Several transcripts of interest are overexpressed in metastases samples compared to primary tumors as showed by microarray analysis and validated by qPCR. These targets are related in literature to metastasis in other cancers, as well as lymph nodes metastasis, which occurs to happen in our model and in ARMS clinics3. Additionally, some transcripts are overexpressed in tumor samples, which are linked to inhibition of proliferation and motility. Conclusions/Future Work: In vitro phenotypic characterization of the obtained targets will involve proliferation (MTT), migration (Transwell®) and clonogenic assays, including loss-of-function (siRNA and commercial inhibitors). Using stable knock-out and knock-in models of the genes of interest, their role in ARMS metastasis will be further studied in vitro and in vivo. The clinical relevance of these targets will be explored in several cohorts of patients by immunohistochemistry on Tissue Microarrays. Studying the profile of paired tumors and metastases provides a unique tool to decipher the mechanisms of tumor progression. Fully understanding the metastatic process will ultimately lead to the development of better targeted therapies and thus to improved outcomes for ARMS patients. Also, these same steps are being followed in our laboratory for Ewing Sarcoma, another developmental tumor with discouraging survival rates for metastatic patients ( Citation Format: Sara Sanchez-Serra, Mariona Chicon-Bosch, Paola Monaco, Laura Santana-Viera, Susana Maqueda-Marcos, Manuel Gris-Lorente, Roser Lopez-Alemany, Oscar M. Tirado. Transcriptomic analysis to unveil alveolar rhabdomyosarcoma metastatic process [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1299.

Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) shows potent preclinical anticancer activity in pediatric solid tumors such as Ewing sarcoma, rhabdomyosarcoma and neuroblastoma, but responses in clinical trials have been modest. In this work, we aimed to discover a rational biomarker-based approach to select the right candidate patients for this treatment. We assessed the efficacy of nab-paclitaxel in 27 patient-derived xenografts (PDX), including 14 Ewing sarcomas, five rhabdomyosarcomas and several other pediatric solid tumors. Response rate (partial or complete response) was remarkable in rhabdomyosarcomas (four of five) and Ewing sarcomas (four of 14). We addressed several predictive factors of response to nab-paclitaxel such as the expression of the secreted protein acidic and rich in cysteine (SPARC), chromosomal stability of cancer cells and expression of antiapoptotic members of the B-cell lymphoma-2 (Bcl-2) family of proteins such as Bcl-2, Bcl-xL, Bcl-W and Mcl-1. Protein (immunoblotting) and gene expression of SPARC correlated positively, while immunoblotting and immunohistochemistry expression of Bcl-2 correlated negatively with the efficacy of nab-paclitaxel in Ewing sarcoma PDX. The negative correlation of Bcl-2 immunoblotting signal and activity was especially robust (r = 0.8352; P = 0.0007; Pearson correlation). Consequently, we evaluated pharmacological strategies to inhibit Bcl-2 during nab-paclitaxel treatment. We observed that the Bcl-2 inhibitor venetoclax improved the activity of nab-paclitaxel in highly resistant Bcl-2-expressing Ewing sarcoma PDX. Overall, our results suggest that low Bcl-2 expression could be used to select patients with Ewing sarcoma sensitive to nab-paclitaxel, and Bcl-2 inhibitors could improve the activity of this drug in Bcl-2-expressing Ewing sarcoma.

Soft-tissue sarcomas (STS) are an uncommon and heterogeneous group of malignancies that result in high mortality. Metastatic STS have very bad prognosis due to the lack of effective treatments. Dinaciclib is a model drug for the family of CDK inhibitors. Its main targets are cell cycle regulator CDK1 and protein synthesis controller CDK9. We present data supporting Dinaciclib ability to inactivate in vitro different STS models at nanomolar concentrations. Moreover, the different rhythms of cell death induction allow us to further study into the mechanism of action of the drug. Cell death was found to respond to the mitochondrial pathway of apoptosis. Anti-apoptotic Bcl-xL was identified as the key regulator of this process. Already natural low levels of pro-apoptotic proteins BIM and PUMA in tolerant cell lines were insufficient to inhibit Bcl-xL as this anti-apoptotic protein showed a slow decay curve after Dinaciclib-induced protein synthesis disruption. Combination of Dinaciclib with BH3-mimetics led to quick and massive apoptosis induction in vitro, but in vivo assessment was prevented due to liver toxicity. Additionally, Bcl-xL inhibitor A-1331852 also synergized with conventional chemotherapy drugs as Gemcitabine. Thus, Bcl-xL targeted therapy arises as a major opportunity to the treatment of STS.

Sarcomas are malignant soft tissue and bone tumours affecting adults, adolescents and children. They represent a morphologically heterogeneous class of tumours and some entities lack defining histopathological features. Therefore, the diagnosis of sarcomas is burdened with a high inter-observer variability and misclassification rate. Here, we demonstrate classification of soft tissue and bone tumours using a machine learning classifier algorithm based on array-generated DNA methylation data. This sarcoma classifier is trained using a dataset of 1077 methylation profiles from comprehensively pre-characterized cases comprising 62 tumour methylation classes constituting a broad range of soft tissue and bone sarcoma subtypes across the entire age spectrum. The performance is validated in a cohort of 428 sarcomatous tumours, of which 322 cases were classified by the sarcoma classifier. Our results demonstrate the potential of the DNA methylation-based sarcoma classification for research and future diagnostic applications., This work was funded by Deutsche Krebshilfe grant 70112499, the NCT Heidelberg and an Illumina Medical Research Grant. Part of this work was funded by the National Institute of Health Research (to S.B. and Z.J.) and to UCLH Biomedical research centre (BRC399/NS/RB/101410). Human tissues were obtained from University College London NHS Foundation Trust as part of the UK Brain Archive Information Network (BRAIN UK, Ref: 18/004) which is funded by the Medical Research Council and Brain Tumour Research UK. The methylation profiling at NYU is supported by a grant from the Friedberg Charitable Foundation (to M.Sn.). M.Mi. would like to thank the Luxembourg National Research Fond (FNR) for the support (FNR PEARL P16/BM/11192868 grant). Open Access funding enabled and organized by Projekt DEAL.

Metastasis at diagnosis is the most adverse prognostic factor in Ewing Sarcoma (ES), drastically decreasing patients’ overall survival down to Citation Format: Sara Sanchez Serra, Mariona Chicon Bosch, Judith Besalú Velazquez, Susana Maqueda Marcos, Paola Monaco, Laura Santana Viera, Roser Lopez Alemany, Oscar M. Tirado. Identification and characterization of key players in the Ewing Sarcoma metastatic process [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2501.

Orthotopic models are based on the implantation of tumor cells directly into the organ of origin, which allows interaction between the cells and the surrounding host tissues.Here we describe a modified version of an orthotopic model that closely recapitulates the steps required for metastasis development in Ewing sarcoma: tumor cells are injected into the calf muscles of the mouse, and once the tumor reaches a certain volume, the muscles containing the tumor are surgically resected. This procedure involves a nonaggressive surgery of the muscle which allows for the survival of the mouse during a period of time that is long enough to enable the development of distant metastases. This spreading of tumor cells to metastatic sites in other organs takes place by a physiological mechanism similar to what occurs in human Ewing sarcoma.

Orthotopic models are based on the implantation of tumor cells directly into the organ of origin, which allows interaction between the cells and the surrounding host tissues.Here we describe a modified version of an orthotopic model that closely recapitulates the steps required for metastasis development in Ewing sarcoma: tumor cells are injected into the calf muscles of the mouse, and once the tumor reaches a certain volume, the muscles containing the tumor are surgically resected. This procedure involves a nonaggressive surgery of the muscle which allows for the survival of the mouse during a period of time that is long enough to enable the development of distant metastases. This spreading of tumor cells to metastatic sites in other organs takes place by a physiological mechanism similar to what occurs in human Ewing sarcoma.

[Purpose] Epigenetic regulation is crucial in mammalian development and maintenance of tissue-cell specific functions. Perturbation of epigenetic balance may lead to alterations in gene expression, resulting in cellular transformation and malignancy. Previous studies in Ewing sarcoma (ES) have shown that the Nucleosome Remodeling Deacetylase (NuRD) complex binds directly to EWS-FLI1 oncoprotein and modulates its transcriptional activity. The role of EWS-FLI1 as a driver of proliferation and transformation in ES is widely known, but the effect of epigenetic drugs on fusion activity remains poorly described. The present study evaluated the combination effects of the histone deacetylases inhibitor suberoylanilide hydroxamic acid (SAHA) and Lysine-specific demethylase1 inhibitor (HCI-2509) on different biological functions in ES and in comparison to monotherapy treatments., [Results] The study of proliferation and cell viability showed a synergistic effect in most ES cell lines analyzed. An enhanced effect was also observed in the induction of apoptosis, together with accumulation of cells in G1 phase and a blockage of the migratory capacity of ES cell lines. Treatment, either in monotherapy or in combination, caused a significant decrease of EWS-FLI1 mRNA and protein levels and this effect is mediated in part by fusion gene promoter regulation. The anti-tumor effect of this combination was confirmed in patient-derived xenograft mouse models, in which only the combination treatment led to a statistically significant decrease in tumor volume., [Conclusions] The combination of SAHA and HCI-2509 is proposed as a novel treatment strategy for ES patients to inhibit the essential driver of this sarcoma and tumor growth., Research in EDA, JM, and OMT labs is supported by Asociación Española Contra el Cáncer (AECC). Enrique de Alava’s lab is also supported by the Ministry of Economy and Competitiveness of Spain-FEDER (CIBERONC, PI11700464, RD06/0020/0059, FMGE) and the European Commission (FP7-HEALTH-2011-two-stage, Project ID278742 EUROSARC). DGD and LHP are supported by Red Temática de Investigación Cooperativa en Cáncer (RD12/0036/0017) and Centro de Investigación Biomédica en Red de Cáncer (CB16/12/00361)S. PRN is supported by a grant from the María García Estrada Foundation. DGD is a PhD researcher funded by the Consejería de Salud, Junta de Andalucía (PI-0197-2016). MJR is supported by the Consejería de Salud, Junta de Andalucía (ECAIF2-0176-2013).

Ewing sarcoma (EwS) is an aggressive tumor that affects adolescents and young adults. EwS is defined by a chromosomal translocation, EWSR1-FLI1 being the most common, that causes genome reprogramming through remodeling of enhancers. Here, we describe an unexpected function of RING1B, which is highly expressed in EwS. While retaining its repressive activity at Polycomb developmental regulated genes, RING1B colocalizes with EWSR1-FLI1 at active enhancers. We demonstrate that RING1B is necessary for the expression of key EWSR1-FLI1 targets by facilitating oncogene recruitment to their enhancers. Knockdown of RING1B impairs growth of tumor xenografts and expression of genes regulated by EWSR1-FLI1 bound enhancers. Pharmacological inhibition of AURKB with AZD1152 increases H2Aub levels causing down-regulation of RING1B/EWSR1-FLI1 common targets. Our findings demonstrate that RING1B is a critical modulator of EWSR1-FLI1–induced chromatin remodeling, and its inhibition is a potential therapeutic strategy for the treatment of these tumors., S.S.-M. and the project were supported by the Spanish Association Against Cancer (AECC) consolidated groups grant (GCB13131578) consortium. The project also had the support from the Asociacion Pablo Ugarte (APU). E.F.-B. was supported by the Spanish government grant, Instituto de Salud Carlos III (PI16/00245) to J.M. The work in the Di Croce laboratory was supported by grants from the Spanish of Economy, Industry and Competitiveness (MEIC) (BFU2016-75008-P), and Fundacion Vencer El Cancer (VEC).

// Laura Lagares-Tena 1 , Silvia Garcia-Monclus 1 , Roser Lopez-Alemany 1 , Olga Almacellas-Rabaiget 1 , Juan Huertas-Martinez 1 , Miguel Sainz-Jaspeado 1 , Silvia Mateo-Lozano 2 , Carlos Rodriguez-Galindo 3 , Santiago Rello-Varona 1 , David Herrero-Martin 1 , Oscar M. Tirado 1 1 Sarcoma Research Group, Institut d’Investigacio Biomedica de Bellvitge-IDIBELL, L’Hospitalet de Llobregat, Barcelona, Spain 2 Developmental Tumor Biology Laboratory, Hospital Sant Joan de Deu, Barcelona, Spain 3 Pediatric Hematology/Oncology, Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Harvard Medical School, Boston, Massachusetts, USA Correspondence to: Oscar M. Tirado, email: omartinez@idibell.cat Keywords: caveolin-1, Ewing sarcoma, metastasis, mmp9, mapk Received: December 22, 2015 Accepted: July 18, 2016 Published: July 28, 2016 ABSTRACT Ewing sarcoma (ES) is a bone and soft tissue sarcoma affecting mostly children and young adults. Caveolin-1 (CAV1) is a well-known target of EWS/FLI1, the main driver of ES, with an oncogenic role in ES. We have previously described how CAV1 is able to induce metastasis in ES via matrix metalloproteinase-9 (MMP-9). In the present study we showed how CAV1 silencing in ES reduced MEK1/2 and ERK1/2 phosphorylation. Accordingly, chemical inhibition of MEK1/2 resulted in reduction in MMP-9 expression and activity that correlated with reduced migration and invasion. IQ Motif Containing GTPase Activating Protein 1 (IQGAP1) silencing reduced MEK1/2 and ERK1/2 phosphorylation and MMP-9 expression. Furthermore, IQGAP1 silenced cells showed a marked decrease in their migratory and invasive capacity. We demonstrated that CAV1 and IQGAP1 localize in close proximity at the cellular edge, thus IQGAP1 could be the connecting node between CAV1 and MEK/ERK in ES metastatic phenotype. Analysis of the phosphorylation profile of CAV1-silenced cells showed a decrease of p-ribosomal protein S6 (RPS6). RPS6 can be phosphorylated by p90 ribosomal S6 kinases (RSK) proteins. CAV1-silenced cells showed reduced levels of p-RSK1 and treatment with U0126 provoked the same effect. Despite not affecting ERK1/2 and RPS6 phosphorylation status neither MMP-9 expression nor activity, RSK1 silencing resulted in a reduced migratory and invasive capacity in vitro and reduced incidence of metastases in vivo in a novel orthotopic model. The present work provides new insights into CAV1-driven metastatic process in ES unveiling novel key nodes.

Soft-tissue sarcomas (STS) are an uncommon and heterogeneous group of malignancies that result in high mortality. Metastatic STS have very bad prognosis due to the lack of effective treatments. Dinaciclib is a model drug for the family of CDK inhibitors. Its main targets are cell cycle regulator CDK1 and protein synthesis controller CDK9. We present data supporting Dinaciclib ability to inactivate in vitro different STS models at nanomolar concentrations. Moreover, the different rhythms of cell death induction allow us to further study into the mechanism of action of the drug. Cell death was found to respond to the mitochondrial pathway of apoptosis. Anti-apoptotic Bcl-xL was identified as the key regulator of this process. Already natural low levels of pro-apoptotic proteins BIM and PUMA in tolerant cell lines were insufficient to inhibit Bcl-xL as this anti-apoptotic protein showed a slow decay curve after Dinaciclib-induced protein synthesis disruption. Combination of Dinaciclib with BH3-mimetics led to quick and massive apoptosis induction in vitro, but in vivo assessment was prevented due to liver toxicity. Additionally, Bcl-xL inhibitor A-1331852 also synergized with conventional chemotherapy drugs as Gemcitabine. Thus, Bcl-xL targeted therapy arises as a major opportunity to the treatment of STS.

Patients with DICER1 predisposition syndrome have an increased risk to develop pleuropulmonary blastoma, cystic nephroma, embryonal rhabdomyosarcoma, and several other rare tumor entities. In this study, we identified 22 primary intracranial sarcomas, including 18 in pediatric patients, with a distinct methylation signature detected by array-based DNA-methylation profiling. In addition, two uterine rhabdomyosarcomas sharing identical features were identified. Gene panel sequencing of the 22 intracranial sarcomas revealed the almost unifying feature of DICER1 hotspot mutations (21/22; 95%) and a high frequency of co-occurring TP53 mutations (12/22; 55%). In addition, 17/22 (77%) sarcomas exhibited alterations in the mitogen-activated protein kinase pathway, most frequently affecting the mutational hotspots of KRAS (8/22; 36%) and mutations or deletions of NF1 (7/22; 32%), followed by mutations of FGFR4 (2/22; 9%), NRAS (2/22; 9%), and amplification of EGFR (1/22; 5%). A germline DICER1 mutation was detected in two of five cases with constitutional DNA available. Notably, none of the patients showed evidence of a cancer-related syndrome at the time of diagnosis. In contrast to the genetic findings, the morphological features of these tumors were less distinctive, although rhabdomyoblasts or rhabdomyoblast-like cells could retrospectively be detected in all cases. The identified combination of genetic events indicates a relationship between the intracranial tumors analyzed and DICER1 predisposition syndrome-associated sarcomas such as embryonal rhabdomyosarcoma or the recently described group of anaplastic sarcomas of the kidney. However, the intracranial tumors in our series were initially interpreted to represent various tumor types, but rhabdomyosarcoma was not among the typical differential diagnoses considered. Given the rarity of intracranial sarcomas, this molecularly clearly defined group comprises a considerable fraction thereof. We therefore propose the designation "spindle cell sarcoma with rhabdomyosarcoma-like features, DICER1 mutant" for this intriguing group.

In the original publication, the second name of the twentieth author was incorrect. It should read as 'Miguel Sáinz-Jaspeado'. The original publication of the article has been updated to reflect the change. This correction was authored by Ulrich Schüller on behalf of all authors of the original publication.

Olfactory neuroblastoma/esthesioneuroblastoma (ONB) is an uncommon neuroectodermal neoplasm thought to arise from the olfactory epithelium. Little is known about its molecular pathogenesis. For this study, a retrospective cohort of n = 66 tumor samples with the institutional diagnosis of ONB was analyzed by immunohistochemistry, genome-wide DNA methylation profiling, copy number analysis, and in a subset, next-generation panel sequencing of 560 tumor-associated genes. DNA methylation profiles were compared to those of relevant differential diagnoses of ONB. Unsupervised hierarchical clustering analysis of DNA methylation data revealed four subgroups among institutionally diagnosed ONB. The largest group (n = 42, 64%, Core ONB) presented with classical ONB histology and no overlap with other classes upon methylation profiling-based t-distributed stochastic neighbor embedding (t-SNE) analysis. A second DNA methylation group (n = 7, 11%) with CpG island methylator phenotype (CIMP) consisted of cases with strong expression of cytokeratin, no or scarce chromogranin A expression and IDH2 hotspot mutation in all cases. T-SNE analysis clustered these cases together with sinonasal carcinoma with IDH2 mutation. Four cases (6%) formed a small group characterized by an overall high level of DNA methylation, but without CIMP. The fourth group consisted of 13 cases that had heterogeneous DNA methylation profiles and strong cytokeratin expression in most cases. In t-SNE analysis, these cases mostly grouped among sinonasal adenocarcinoma, squamous cell carcinoma, and undifferentiated carcinoma. Copy number analysis indicated highly recurrent chromosomal changes among Core ONB with a high frequency of combined loss of chromosome 1-4, 8-10, and 12. NGS sequencing did not reveal highly recurrent mutations in ONB, with the only recurrently mutated genes being TP53 and DNMT3A. In conclusion, we demonstrate that institutionally diagnosed ONB are a heterogeneous group of tumors. Expression of cytokeratin, chromogranin A, the mutational status of IDH2 as well as DNA methylation patterns may greatly aid in the precise classification of ONB.

ABSTRACT Desmoplastic small round cell tumor (DSRCT) was proposed as a distinct disease entity by William L Gerald and Juan Rosai in 1991. Over 850 patients have been reported in the medical literature. A specific translocation, t(11;22)(p13;q12), is seen in almost all cases, juxtaposing the EWS gene to the WT1 tumor suppressor gene. DSRCT is composed of nests of small round cells with polyphenotypic differentiation, typically a mixture of epithelial, mesenchymal and neural features, surrounded by a prominent desmoplastic stroma. DSRCT has a predilection for adolescent and young adult males, and primarily involves the abdominal cavity and pelvis. Survival is low despite their initial response to multimodal treatment. Most patients relapse with disseminated disease that is unresponsive to further therapy.

During the last decades, the knowledge of cell death mechanisms involved in anticancer therapy has grown exponentially. However, in many studies, cell death is still described in an incomplete manner. The frequent use of indirect proliferation assays, unspecific probes, or bulk analyses leads too often to misunderstandings regarding cell death events. There is a trend to focus on molecular or genetic regulations of cell demise without a proper characterization of the phenotype that is the object of this study. Sometimes, cancer researchers can feel overwhelmed or confused when faced with such a corpus of detailed insights, nomenclature rules, and debates about the accuracy of a particular probe or assay. On the basis of the information available, we propose a simple guide to distinguish forms of cell death in experimental settings using cancer cell lines. Cancer Res; 75(6); 913–7. ©2015 AACR.

Gemcitabine plus sirolimus enhances apoptosis in vitro and increases anti-tumor efficacy in vivo in soft-tissue sarcoma (STS) models. The objective of this study was to evaluate the activity and toxicity of the combination of gemcitabine plus sirolimus in patients with STS after failure of standard chemotherapy. Advanced STS patients, previously treated with doxorubicin and/or ifosfamide, were included in this single-arm phase II study. Patients received gemcitabine 800 mg/m2 intravenously (iv) at 10 mg/m2/min on days 1 and 8 every 3 weeks plus sirolimus 5 mg daily orally (po). After enrolment of the first 12 patients, the study protocol was amended due to toxicity and the starting dose of sirolimus was reduced to 3 mg daily po. Archival tumor samples were analyzed for extracellular signal-regulated kinase 1 and 2 (ERK1/2) expression and correlated with outcome. The primary endpoint was progression-free rate (PFR) at 3 months. From May 2012 to May 2013, 28 patients were enrolled at eight centers. PFR at 3 and 6 months was 44% and 20%, respectively, with 12 patients being free of progression at 3 months. Median progression-free survival (PFS) was 1.85 months (95% confidence interval [CI] 0.73–2.97) and median overall survival (OS) was 9.2 months (95% CI 5.8–12.5). No responses were observed. The most common grade 3–4 hematologic toxicities were neutropenia (48%) and leukopenia (41%) and the most frequent grade 3 non-hematologic toxicities were infection (18.5%), transaminitis (15%), fatigue (11%), and pneumonitis (11%). ERK1/2 expression was significantly correlated with PFS (p = 0.026). The combination of gemcitabine and sirolimus is an active treatment in STS. Further investigation is warranted. ClinicalTrials.gov identifier: NCT01684449.

Ewing sarcoma (ES) is the second most common bone malignancy affecting children and young adults with poor prognosis due to high metastasis incidence. Our group previously described that EphA2, a tyrosine kinase receptor, promotes angiogenesis in Ewing sarcoma (ES) cells via ligand-dependent signaling. Now we wanted to explore EphA2 ligand-independent activity, controlled upon phosphorylation at S897 (p-EphA2(S897)), as it has been linked to metastasis in several malignancies. By reverse genetic engineering we explored the phenotypic changes after EphA2 removal or reintroduction. Gene expression microarray was used to identify key players in EphA2 signaling. Mice were employed to reproduce metastatic processes from orthotopically implanted engineered cells. We established a correlation between ES cells aggressiveness and p-EphA2(S897). Moreover, stable overexpression of EphA2 in low EphA2 expression ES cells enhanced proliferation and migration, but not a non-phosphorylable mutant (S987A). Consistently, silencing of EphA2 reduced tumorigenicity, migration and invasion in vitro, and lung metastasis incidence in experimental and spontaneous metastasis assays in vivo. A gene expression microarray revealed the implication of EphA2 in cell signaling, cellular movement and survival. ADAM19 knockdown by siRNA technology strongly reproduced the negative effects on cell migration observed after EphA2 silencing. Altogether, our results suggest that p-EphA2(S897) correlates with aggressiveness in ES, so blocking its function may be a promising treatment.

Epigenetic modifications have been shown to be important in developmental tumors as Ewing sarcoma. We profiled the DNA methylation status of 15 primary tumors, 7 cell lines, 10 healthy tissues and 4 human mesenchymal stem cells lines samples using the Infinium Human Methylation 450K. Differential methylation analysis between Ewing sarcoma and reference samples revealed 1166 hypermethylated and 864 hypomethylated CpG sites (Bonferroni p < 0.05, delta-beta-value with absolute difference of >0.20) corresponding to 392 and 470 genes respectively. Gene Ontology analysis of genes differentially methylated in Ewing sarcoma samples showed a significant enrichment of developmental genes. Membrane and cell signal genes were also enriched, among those, 11 were related to caveola formation. We identified differential hypermethylation of CpGs located in the body and S-Shore of the PTRF gene in Ewing sarcoma that correlated with its repressed transcriptional state. Reintroduction of PTRF/Cavin-1 in Ewing sarcoma cells revealed a role of this protein as a tumor suppressor. Restoration of caveolae in the membrane of Ewing sarcoma cells, by exogenously reintroducing PTRF, disrupts the MDM2/p53 complex, which consequently results in the activation of p53 and the induction of apoptosis. (C) 2016 Elsevier Ireland Ltd. All rights reserved.

Altres ajuts: This work was supported by grants from Institut Català d'Oncologia (ICO), Instituto de Salud Carlos III (RTICC-RD12/0036/0016, /0020, /0035, /0057; and PI14/00647), Fundació A BOSCH, Fundació Amics Joan Petit, ajuts predoctorals del VHIR and RIS3CAT grants COMRDI15-1-0014 (ACCIÓ and FEDER). Altres ajuts: FEDER/COMRDI15-1-0014 Rhabdomyosarcoma (RMS) is the most common type of soft tissue sarcoma in children. The Hedgehog (HH) pathway is known to develop an oncogenic role in RMS. However, the molecular mechanism that drives activation of the pathway in RMS is not well understood. The expression of HH ligands was studied by qPCR, western blot and immunohistochemistry. Functional and animal model studies were carried out with cells transduced with shRNAs against HH ligands or treated with HH-specific inhibitors (Vismodegib and MEDI-5304). Finally, the molecular characterisation of an off-target effect of Vismodegib was also made. The results showed a prominent expression of HH ligands supporting an autocrine ligand-dependent activation of the pathway. A comparison of pharmacologic Smoothened inhibition (Vismodegib) and HH ligand blocking (MEDI-5304) is also provided. Interestingly, a first description of pernicious off-target effect of Vismodegib is also reported. The clarification of the HH pathway activation mechanism in RMS opens a door for targeted therapies against HH ligands as a possible alternative in the future development of better treatment protocols. Moreover, the description of a pernicious off-target effect of Vismodegib, via unfolded protein response activation, may mechanistically explain its previously reported inefficiency in several ligand-dependent cancers.

The developmental receptor NOTCH plays an important role in various human cancers as a consequence of oncogenic mutations. Here we describe a novel mechanism of NOTCH-induced tumor suppression involving modulation of the deacetylase SIRT1, providing a rationale for the use of SIRT1 inhibitors to treat cancers where this mechanism is inactivated because of SIRT1 overexpression. In Ewing sarcoma cells, NOTCH signaling is abrogated by the driver oncogene EWS-FLI1. Restoration of NOTCH signaling caused growth arrest due to activation of the NOTCH effector HEY1, directly suppressing SIRT1 and thereby activating p53. This mechanism of tumor suppression was validated in Ewing sarcoma cells, B-cell tumors, and human keratinocytes where NOTCH dysregulation has been implicated pathogenically. Notably, the SIRT1/2 inhibitor Tenovin-6 killed Ewing sarcoma cells in vitro and prohibited tumor growth and spread in an established xenograft model in zebrafish. Using immunohistochemistry to analyze primary tissue specimens, we found that high SIRT1 expression was associated with Ewing sarcoma metastasis and poor prognosis. Our findings suggest a mechanistic rationale for the use of SIRT1 inhibitors being developed to treat metastatic disease in patients with Ewing sarcoma. Cancer Res; 74(22); 6578–88. ©2014 AACR.

Contains fulltext : 167540.pdf (Publisher’s version ) (Open Access) This report summarizes the results of the 3rd Joint ENCCA-WP7, EuroSarc, EEC, PROVABES, and EURAMOS European Bone Sarcoma Network Meeting, which was held at the Children's Cancer Research Institute in Vienna, Austria on September 24-25, 2015. The joint bone sarcoma network meetings bring together European bone sarcoma researchers to present and discuss current knowledge on bone sarcoma biology, genetics, immunology, as well as results from preclinical investigations and clinical trials, to generate novel hypotheses for collaborative biological and clinical investigations. The ultimate goal is to further improve therapy and outcome in patients with bone sarcomas.

Despite multimodal treatment, long term outcome for patients with Ewing sarcoma is still poor. The second >European interdisciplinary Ewing sarcoma research summit> assembled a large group of scientific experts in the field to discuss their latest unpublished findings on the way to the identification of novel therapeutic targets and strategies. Ewing sarcoma is characterized by a quiet genome with presence of an EWSR1-ETS gene rearrangement as the only and defining genetic aberration. RNAsequencing of recently described Ewing-like sarcomas with variant translocations identified them as biologically distinct diseases. Various presentations adressed mechanisms of EWS-ETS fusion protein activities with a focus on EWS-FLI1. Data were presented shedding light on the molecular underpinnings of genetic permissiveness to this disease uncovering interaction of EWS-FLI1 with recently discovered susceptibility loci. Epigenetic context as a consequence of the interaction between the oncoprotein, cell type, developmental stage, and tissue microenvironment emerged as dominant theme in the discussion of the molecular pathogenesis and inter- and intratumor heterogeneity of Ewing sarcoma, and the difficulty to generate animal models faithfully recapitulating the human disease. The problem of preclinical development of biologically targeted therapeutics was discussed and promising perspectives were offered from the study of novel in vitro models. Finally, it was concluded that in order to facilitate rapid pre-clinical and clinical development of novel therapies in Ewing sarcoma, the community needs a platform to maintain knowledge of unpublished results, systems and models used in drug testing and to continue the open dialogue initiated at the first two Ewing sarcoma summits., The conference was supported by the European Union’s Seventh Framework Programme grants 261743(ENCCA) and 259348 (ASSET).

Sarcomas represent a heterogeneous group of tumors with a complex and difficult reproducible classification. Their pathogenesis is poorly understood and there are few effective treatment options for advanced disease. Caveolin-1 is a multifunctional scaffolding protein with multiple binding partners that regulates multiple cancer-associated processes including cellular transformation, tumor growth, cell death and survival, multidrug resistance, angiogenesis, cell migration and metastasis. However, ambiguous roles have been ascribed to caveolin-1 in signal transduction and cancer, including sarcomas. In particular, evidence indicating that caveolin-1 function is cell context dependent has been repeatedly reported. Caveolin-1 appears to act as a tumor suppressor protein at early stages of cancer progression. In contrast, a growing body of evidence indicates that caveolin-1 is up-regulated in several multidrug-resistant and metastatic cancer cell lines and human tumor specimens. This review is focused on the role of caveolin-1 in several soft tissue and bone sarcomas and discusses the use of this protein as a potential diagnostic and prognostic marker and as a therapeutic target.

11582Background: Soft tissue sarcomas (STSs) present high mortality rates when metastatic and therefore identification of new active therapies is needed. Dinaciclib is a promising CDK inhibitor und...

Ewing sarcoma (ES) and alveolar rhabdomyosarcoma (ARMS) are pediatric sarcomas characterized by tumor-specific translocations. Besides acting as a direct modulator of transcription, fusion proteins appear to exert its oncogenic functions by epigenetic modifications on the transcriptome. Therefore, the identification of specific DNA methylation markers would be helpful for understanding their pathogenetic mechanism as well as for developing new therapeutic strategies. By using the Illumina Infinium HumanMethylation450 we have analyzed the methylome of ES and ARMS tumors and cell lines. ES and ARMS samples showed, among other epigenetic alterations, differential hypermethylation in the promoter of MIR10A-5p, thus suggesting an inhibition of its expression. Expression of MIR10A-5p is effectively low in ES and ARMS cell lines and patient samples and the treatment with the epigenetic modifier 5-aza restores its expression. MIR10A-5p stable overexpression in two ES (A673 and TC252) and two ARMS (Rh4 and RMS13) cell lines reduces proliferation, diminishes clonogenic growth, and decreases cellular migration. Cell death induced by MIR10A-5p reintroduction is only achieved in the p53wt ES cell line TC252. Proteomic profile of A673 MIR10A-5p cells is altered as assessed by iTRAQ. Protein kinase CRKL is one of the proteins downregulated due to MIR10A-5p reintroduction. Indeed, CRKL expression is also reduced in the other three MIR10A-5p stable overexpression models. Doxycycline-induced silencing of CRKL in ARMS cell line Rh30 provokes cell growth reduction in vitro and in vivo, G0/G1 arrest, and a decrease in the clonogenic capacity (Yeung CL et al., 2013). Interestingly, the migratory ability of Rh30 and A673 CRKL-silenced cells is also impaired. Thus, our results uncover MIR10A-5p as a putative tumor suppressor in ES and ARMS, suggesting a link between MIR10A-5p and CRKL. Further characterization of the oncogenic role of CRKL and the molecular mechanisms associated to MIR10A-5p tumor-suppressor activities in ES and ARMS is ongoing. Citation Format: David Herrero-Martin, Santiago Rello-Varona, Silvia Garcia-Monclus, Juan Huertas-Martinez, Olga Almacellas-Rabaiget, Lee J. Helman, Oscar M. Tirado. Tumor-suppressive activities associated to MIR10A-5p expression in developmental sarcomas [abstract]. In: Proceedings of the AACR Conference on Advances in Sarcomas: From Basic Science to Clinical Translation; May 16-19, 2017; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(2_Suppl):Abstract nr B19.

Rhabdomyosarcoma (RMS) is the most common soft-tissue malignancy in childhood and adolescence that originates as a consequence of regulatory disruption in the growth and differentiation of muscle precursor cells. Members of the lysyl oxidase family of proteins (LOX and LOXL1-4) are amine oxidases that catalyze the covalent crosslinking of collagen and elastin in the extracellular matrix. Apart from their traditional role, novel functions have been attributed to these proteins related to tumor progression. In this study we sought to unravel the potential role of this family of proteins during the progression of RMS. By qRT-PCR and Western blot, lysyl oxidase-like 2 (LOXL2) was found overexpressed in RMS cell lines compared to other sarcoma cells. Then we characterized LOXL2 in RMS cell lines by analyzing the subcellular localization by immunofluorescence and subcellular fractionation. Post-translational modifications were also analyzed: glycosylation and proteolytic processing by tunicamycin treatment and secretion by analysis of the conditioned media by Western blot. Moreover, we characterized the neoplastic phenotype after silencing LOXL2 in two RMS cell lines (RH4 and CW9019). Stable LOXL2 knockdown resulted in a decrease in their clonogenic, proliferative, and cell migratory capabilities. On the other hand, reexpression of LOXL2 in RH28 cells using wild-type or mutated (catalytically inactive) constructs resulted in an increase in cell proliferation and migration, independently of its catalytic activity. Finally, in vivo experiments using an orthotopic model of tumor generation inside the muscle will be carried out to further evaluate the tumorigenic role of LOXL2. Taking all into consideration, our results suggest an oncogenic role of LOXL2 in RMS. Citation Format: Olga Almacellas Rabaiget, Juan Huertas Martínez, Silvia Garcia Monclús, Santiago Rello Varona, David Herrero Martín, Roser López Alemany, Oscar M. Tirado. Uncovering the role of lysyl oxidase-like 2 in rhabdomyosarcoma [abstract]. In: Proceedings of the AACR Conference on Advances in Sarcomas: From Basic Science to Clinical Translation; May 16-19, 2017; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(2_Suppl):Abstract nr B22.

Caveolin-1 (CAV1) has been implicated in the regulation of several signaling pathways and in oncogenesis. Previously, we identified CAV1 as a key determinant of the oncogenic phenotype and tumorigenic activity of cells from tumors of the Ewing's Sarcoma Family (ESFT). However, the possible CAV1 involvement in the chemotherapy resistance commonly presented by an ESFT subset has not been established to date. This report shows that CAV1 expression determines the sensitivity of ESFT cells to clinically relevant chemotherapeutic agents. Analyses of endogenous CAV1 levels in several ESFT cells and ectopic CAV1 expression into ESFT cells expressing low endogenous CAV1 showed that the higher the CAV1 levels, the greater their resistance to drug treatment. Moreover, results from antisense- and shRNA-mediated gene expression knockdown and protein re-expression experiments demonstrated that CAV1 increases the resistance of ESFT cells to doxorubicin (Dox)- and cisplatin (Cp)-induced apoptosis by a mechanism involving the activating phosphorylation of PKCalpha. CAV1 knockdown in ESFT cells led to decreased phospho(Thr(638))-PKCalpha levels and a concomitant sensitization to apoptosis, which were reversed by CAV1 re-expression. These results were recapitulated by PKCalpha knockdown and re-expression in ESFT cells in which CAV1 was previously knocked down, thus demonstrating that phospho(Thr(638))-PKCalpha acts downstream of CAV1 to determine the sensitivity of ESFT cells to chemotherapeutic drugs. These data, along with the finding that CAV1 and phospho(Thr(638))-PKCalpha are co-expressed in approximately 45% of ESFT specimens tested, imply that targeting CAV1 and/or PKCalpha may allow the development of new molecular therapeutic strategies to improve the treatment outcome for patients with ESFT.

Protein kinases represent promising anticancer drug targets. We describe here the meriolins, a new family of inhibitors of cyclin-dependent kinases (CDK). Meriolins represent a chemical structural hybrid between meridianins and variolins, two families of kinase inhibitors extracted from various marine invertebrates. Variolin B is currently in preclinical evaluation as an antitumor agent. A selectivity study done on 32 kinases showed that, compared with variolin B, meriolins display enhanced specificity toward CDKs, with marked potency on CDK2 and CDK9. The structures of pCDK2/cyclin A/variolin B and pCDK2/cyclin A/meriolin 3 complexes reveal that the two inhibitors bind within the ATP binding site of the kinase, but in different orientations. Meriolins display better antiproliferative and proapoptotic properties in human tumor cell cultures than their parent molecules, meridianins and variolins. Phosphorylation at CDK1, CDK4, and CDK9 sites on, respectively, protein phosphatase 1α, retinoblastoma protein, and RNA polymerase II is inhibited in neuroblastoma SH-SY5Y cells exposed to meriolins. Apoptosis triggered by meriolins is accompanied by rapid Mcl-1 down-regulation, cytochrome c release, and activation of caspases. Meriolin 3 potently inhibits tumor growth in two mouse xenograft cancer models, namely, Ewing's sarcoma and LS174T colorectal carcinoma. Meriolins thus constitute a new CDK inhibitory scaffold, with promising antitumor activity, derived from molecules initially isolated from marine organisms. [Cancer Res 2007;67(17):8325–34]