Insulin-Like Growth Factor 2 mRNA-Binding Protein 3 is a Novel Post-Transcriptional Regulator of Ewing Sarcoma Malignancy.

Purpose: Large-scale sequencing studies have indicated that besides genomic alterations, the posttranscriptional regulation of gene expression or epigenetic mechanisms largely influences the clinical behavior of Ewing sarcoma. We investigated the significance of the RNA-binding protein IGF2BP3 in the regulation of Ewing sarcoma aggressiveness.Experimental Design: Explorative study was performed in 14 patients with localized Ewing sarcoma using RNA sequencing. Next, 128 patients with localized Ewing sarcoma were divided into two cohorts. In the training set, 29 Ewing sarcoma samples were analyzed using Affymetrix GeneChip arrays. In the validation set, 99 Ewing sarcoma samples were examined using qRT-PCR. Patient-derived cell lines and experimental models were used for functional studies.Results:Univariate and multivariate analyses indicated IGF2BP3 as a potent indicator of poor prognosis. Furthermore, ABCF1 mRNA was identified as a novel partner of IGF2BP3. Functional studies indicated IGF2BP3 as an oncogenic driver and ABCF1 mRNA as a sponge that by binding IGF2BP3, partly repressed its functions. The combined evaluation of IGF2BP3 and ABCF1 could identify different patient outcomes-high IGF2BP3 and low ABCF1 levels indicated poor survival (25%), whereas low IGF2BP3 and high ABCF1 levels indicated favorable survival (85.5%). The bromodomain and extraterminal domain inhibitor (BETi) JQ1 decreased IGF2BP3 expression, modified the expression of its validated targets and inhibited the capability of Ewing sarcoma cells to grow under anchorage-independent conditions.Conclusions: The combined assessment of IGF2BP3 and ABCF1 predicts recurrence in Ewing sarcoma patients. Thus, for patients with high expression of IGF2BP3 and poor probability of survival, the use of BETis should be clinically evaluated. Clin Cancer Res; 24(15); 3704-16. ©2018 AACR.

Human myeloma cell lines induce osteoblast downregulation of CD99 which is involved in osteoblast formation and activity.

CD99 is a transmembrane glycoprotein expressed in physiological conditions by cells of different tissues, including osteoblasts (OBs). High or low CD99 levels have been detected in various pathological conditions, and the supernatant of some carcinoma cell lines can modulate CD99 expression in OB-like cells. In the present work we demonstrate for the first time that two different human myeloma cell lines (H929 and U266) and, in a less degree, their conditioned media significantly downregulate CD99 expression in normal human OBs during the differentiation process. In the same experimental conditions the OBs display a less differentiated phenotype as demonstrated by the decreased expression of RUNX2 and Collagen I. On the contrary, when CD99 was activated by using a specific agonist antibody, the OBs become more active as demonstrated by the upregulation of Alkaline Phosphatase, Collagen I, RUNX2, and JUND expression. Furthermore, we demonstrate that the activation of CD99 is able to induce the phosphorylation of ERK 1/2 and AKT intracellular signal transduction molecules in the OBs.

ERG deregulation induces IGF-1R expression in prostate cancer cells and affects sensitivity to anti-IGF-1R agents.

Identifying patients who may benefit from targeted therapy is an urgent clinical issue in prostate cancer (PCa). We investigated the molecular relationship between TMPRSS2-ERG (T2E) fusion gene and insulin-like growth factor receptor (IGF-1R) to optimize the use of IGF-1R inhibitors.IGF-1R was analyzed in cell lines and in radical prostatectomy specimens in relation to T2E status. ERG binding to IGF-1R promoter was evaluated by chromatin immunoprecipitation (ChIP). Sensitivity to anti-IGF-1R agents was evaluated alone or in combination with anti-androgen abiraterone acetate in vitro at basal levels or upon ERG modulation.IGF-1R analysis performed in PCa cells or clinical samples showed that T2E expression correlated with higher IGF-1R expression at mRNA and protein levels. Genetic modulation of ERG directly affected IGF-1R protein levels in vitro. ChIP analysis showed that ERG binds IGF-1R promoter and that promoter occupancy is higher in T2E-positive cells. IGF-1R inhibition was more effective in cell lines expressing the fusion gene and combination of IGF-1R inhibitors with abiraterone acetate produced synergistic effects in T2E-expressing cells.Here, we provide the rationale for use of T2E fusion gene to select PCa patients for anti-IGF-1R treatments. The combination of anti-IGF-1R-HAbs with an anti-androgen therapy is strongly advocated for patients expressing T2E.

The first European interdisciplinary ewing sarcoma research summit.

The European Network for Cancer Research in Children and Adolescents (ENCCA) provides an interaction platform for stakeholders in research and care of children with cancer. Among ENCCA objectives is the establishment of biology-based prioritization mechanisms for the selection of innovative targets, drugs, and prognostic markers for validation in clinical trials. Specifically for sarcomas, there is a burning need for novel treatment options, since current chemotherapeutic treatment protocols have met their limits. This is most obvious for metastatic Ewing sarcoma (ES), where long term survival rates are still below 20%. Despite significant progress in our understanding of ES biology, clinical translation of promising laboratory results has not yet taken place due to fragmentation of research and lack of an institutionalized discussion forum. To fill this gap, ENCCA assembled 30 European expert scientists and five North American opinion leaders in December 2011 to exchange thoughts and discuss the state of the art in ES research and latest results from the bench, and to propose biological studies and novel promising therapeutics for the upcoming European EWING2008 and EWING2012 clinical trials.

miR-34a predicts survival of Ewing's sarcoma patients and directly influences cell chemo-sensitivity and malignancy.

Identification of factors to detect chemotherapy-resistant tumours at diagnosis is a first priority for risk-adapted therapy in the oncology of children and young adults, where more individualized, effective, and less toxic treatments are highly desirable. In this study, we analysed the miRNAs discriminating Ewing's sarcoma (EWS) patients with different clinical outcomes in order to identify new indicators of prognosis. miRNA expression was investigated in 49 primary EWSs by using the Agilent human miRNA microarray v.2 and/or qRT-PCR. Statistical power of the samples studied for miRNA expression was verified, indicating adequate sample size. Microarray analysis defined a signature of five miRNAs (miR-34a, miR-23a, miR-92a, miR-490-3p, and miR-130b) as an independent predictor of risk for disease progression and survival. Validation analysis in the extended sample set indicated that both miR-34a and miR-490-3p achieved sufficient statistical power to predict prognosis. Results were particularly robust for miR-34a, which appeared associated with either event-free or overall survival and emerged as a significant predictor also after multivariate analysis. Patients with the highest expression of miR-34a did not experience adverse events in 5 years; in contrast, patients with the lowest expression recurred within 2 years. High expression of miR34a can be detected also in paraffin-embedded tissues by in situ hybridization, thus contributing to an easy routine evaluation of this miRNA. Functional analysis of miR-34a in EWS cell lines indicated that when miR-34a expression was enforced, cells were less proliferative, less malignant, and sensitized to doxorubicin and vincristine. Expression of miR-34a could be increased in p53wt cells by treatment with nutlin-3a. Accordingly, nutlin-3a synergizes with doxorubicin. Overall, our data indicate that miR-34a expression is a strong predictor of outcome in EWS. Restoration of miR-34a activity may be useful to decrease malignancy and increase tumour sensitivity to current drugs, so sparing excessive long-term toxicity to EWS patients.

Expression of insulin-like growth factor system components in Ewing's sarcoma and their association with survival.

AIMS: The role of IGF system in the pathogenesis of Ewing's sarcoma (EWS) is well-documented. However, still little information is available about the value of IGF system components as indicators of prognosis. Understanding the clinical role for IGF system in EWS patients may be important because different subtypes of patients have distinct outcome and may require different treatment protocol. We evaluated the expression of insulin-like growth factor (IGF)-receptor (IGF-IR), insulin receptor (IR), IGF-I and some major intracellular mediators (IRS1, p-ERK) in specimens from EWS patients with primary localised untreated tumours. PATIENTS AND METHODS: 290 samples were used for immunohistochemistry studies; 57 samples for Real-Time PCR studies; and serum of 67 patients for ELISA. RESULTS: IGF-IR and IR are expressed in virtually all EWS tumours. Usually both the receptors are present in the same tumour but when one receptor is lacking the other one is always present. Evaluation of IGF-IR, IR and IGF-I with quantitative methods may discriminate differential levels of expression with influences on the patients' outcome. High expression of IGF-IR, IR and IGF-I mRNAs is significantly associated with more favourable clinical outcomes. Higher circulating levels of IGF-I also correlated with lower risk to disease progression and death. CONCLUSIONS: Overall, our clinical data are in contrast with the assumption that higher amounts of IGF/IGF-IR are a surrogate for higher aggressiveness and indicate that in some cancers the transition to frank malignancy and poor treatment responsiveness seem to be associated with a reduction of IGF system activity.

NVP-BEZ235 as a new therapeutic option for sarcomas.

PURPOSE: To evaluate the in vitro and in vivo effects of NVP-BEZ235, a dual pan-phosphoinositide 3-kinase-mammalian target of rapamycin inhibitor in the three most common musculoskeletal tumors (osteosarcoma, Ewing's sarcoma, and rhabdomyosarcoma). EXPERIMENTAL DESIGN: Antiproliferative activity as well as the effects on migration and metastasis were evaluated in a panel of osteosarcoma, Ewing's sarcoma, as well as rhabdomyosarcoma cell lines. Moreover, simultaneous and sequential treatments were done in association with two of the most important conventional drugs in the treatment of sarcoma, doxorubicin and vincristine. RESULTS: NVPBEZ235 effectively blocked the pathway in in vitro and in vivo settings. Under the experimental conditions tested, the compound induced disease stasis, by arresting cells in G(1) phase of cell cycle, without remarkable effects on apoptosis. As a consequence, to obtain the maximum exploitation of its therapeutic potential, NVP-BEZ235 has been evaluated in combination with conventional cytotoxic agents, thus showing promising efficacy with either doxorubicin and vincristine. Inhibition of the phosphoinositide 3-kinase/mammalian target of rapamycin pathway increased activation of extracellular signal-regulated kinase 1/2, likely due to the presence of autocrine circuits shifting growth factor signaling toward the mitogen-activated protein kinase pathway. This supports the combined use of NVP-BEZ235 with other small signaling inhibitors. Here, we showed synergistic effects when the compound was associated with a anti-insulin-like growth factor-I receptor tyrosine kinase inhibitor. NVP-BEZ235 also inhibited cell migration and metastasis. Combination with vincristine further potentiated the antimetastatic effects. CONCLUSIONS: NVP-BEZ235 displays the features to be considered for sarcoma therapy to potentiate the activity of other anticancer agents. The drug is currently undergoing phase I/II clinical trials in advanced cancer patients.