Identification of new drugs is strongly needed for sarcomas.

Ewing sarcoma (EWS) is an aggressive bone tumor of uncertain cellular origin. CD99 is a membrane protein that is expressed in most cases of EWS, although its function in the disease is unknown. Here we have shown that endogenous CD99 expression modulates EWS tumor differentiation and malignancy. We determined that knocking down CD99 expression in human EWS cell lines reduced their ability to form tumors and bone metastases when xenografted into immunodeficient mice and diminished their tumorigenic characteristics in vitro. Further, reduction of CD99 expression resulted in neurite outgrowth and increased expression of β-III tubulin and markers of neural differentiation. Analysis of a panel of human EWS cells revealed an inverse correlation between CD99 and H-neurofilament expression, as well as an inverse correlation between neural differentiation and oncogenic transformation. As knockdown of CD99 also led to an increase in phosphorylation of ERK1/2, we suggest that the CD99-mediated prevention of neural differentiation of EWS occurs through MAPK pathway modulation. Together, these data indicate a new role for CD99 in preventing neural differentiation of EWS cells and suggest that blockade of CD99 or its downstream molecular pathway may be a new therapeutic approach for EWS.

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.

Altered expression of CCN3 has been observed in a variety of musculoskeletal tumours, including Ewing's sarcoma (ES). Despite its widespread distribution, very little is known about its biological functions and molecular mechanisms of action. We transfected CCN3 gene into a CCN3-negative ES cell line and analysed the in vitro and in vivo behaviours of stably transfected clones. Forced expression of CCN3 significantly reduced cell proliferation in vitro, growth in anchorage-independent conditions, and tumorigenicity in nude mice. Despite the antiproliferative effect, CCN3-transfected ES cells displayed increased migration and invasion of Matrigel. The decreased expression of a2b1 integrin receptor and the increased amount of cell surface-associated matrix metalloproteinase (MMP)-9 following the expression of CCN3 may be the basis for the increased migratory abilities of transfected cells. Cells lacking a 2 b 1 are less facilitated to have stable anchorage since the predominant collagen extracted from ES tissue is indeed type I collagen, and proMMP-9 was recently found to provide a cellular switch between stationary and migratory ES cell phase. Our findings are in line with those recently obtained in glioblastoma. However, the underlying molecular mechanisms appear to be different, further highlighting the importance of the cellular context in the regulation of function of CCN proteins.

Purpose: Small-molecule insulin-like growth factor-I receptor (IGF-IR)-specific tyrosine kinase inhibitors have been recently proposed as clinically viable approaches to impair IGF-IR functions. NVP-AEW541 seems one of the most promising agents. In this article, we point out its effects against migration, metastasis, vasculogenicity, and angiogenesis of Ewing's sarcoma cells. Experimental Design: In vivo NVP-AEW541effectiveness was analyzed againstTC-71Ewing's sarcoma growth and bone metastasis after cell inoculation in athymic mice. Activity of the compound against angiogenesis as well as vasculogenesis properties was also considered both in vitro and in xenografts. Serum glucose, urea, transaminase levels, as well as other signs of distress were checked in mice treated with the IGF-IR inhibitor. Results: Significant inhibition of migration, metastasis, vasculogenicity, and angiogenesis was recorded after treatment of Ewing's sarcoma cells with NVP-AEW541. In view of its application and the similarity of insulin receptor and IGF-IR, diabetogenic side effects were considered. We observed a significant decrease of glucose blood serum due to increased glucose uptake at cellular level and an increase in urea concentration. Moreover, an initial weight loss was observed in mice bearing tumors. All these side effects were similarly detected in mice treated with vincristine. After the first days of treatment, all the animals started to grow again. Conclusions: Our results globally reinforce the idea that IGF-IR inhibitor NVP-AEW541 could have a role in future combined therapies and suggest to pursue a thorough molecular analysis of the metabolic activity of IGF-IR to avoid possible side effects of these inhibitors.

Previous work had suggested that recombinant CCN3 was partially inhibiting cell proliferation. Here we show that native CCN3 protein secreted into the conditioned medium of glioma transfected cells indeed induces a reduction in cell proliferation. Large amounts of CCN3 are shown to accumulate both cytoplasmically and extracellularly as cells reach high density, therefore highlighting new aspects on how cell growth may be regulated by CCN proteins. Evidence is presented establishing that the amount of CCN3 secreted into cell culture medium is regulated by post-translational proteolysis. As a consequence, the production of CCN3 varies throughout the cell cycle and CCN3 accumulates at the G2/M transition of the cycle. We also show that CCN3-induced inhibition of cell growth can be partially reversed by specific antibodies raised against a C-terminal peptide of CCN3. The use of several clones expressing various portions of CCN3 established that the CT module of CCN3 is sufficient to induce cell growth inhibition.

BackgroundEwing sarcoma family of tumors (ESFT), characterized by t(11;22)(q24;q12), is one of the most common tumors of bone in children and young adults. In addition to EWS/FLI1 gene fusion, copy number changes are known to be significant for the underlying neoplastic development of ESFT and for patient outcome. Our genome-wide high-resolution analysis aspired to pinpoint genomic regions of highest interest and possible target genes in these areas.MethodsArray comparative genomic hybridization (CGH) and expression arrays were used to screen for copy number alterations and expression changes in ESFT patient samples. A total of 31 ESFT samples were analyzed by aCGH and in 16 patients DNA and RNA level data, created by expression arrays, was integrated. Time of the follow-up of these patients was 5–192 months. Clinical outcome was statistically evaluated by Kaplan-Meier/Logrank methods and RT-PCR was applied on 42 patient samples to study the gene of the highest interest.ResultsCopy number changes were detected in 87% of the cases. The most recurrent copy number changes were gains at 1q, 2, 8, and 12, and losses at 9p and 16q. Cumulative event free survival (ESFT) and overall survival (OS) were significantly better (P < 0.05) for primary tumors with three or less copy number changes than for tumors with higher number of copy number aberrations. In three samples copy number imbalances were detected in chromosomes 11 and 22 affecting the FLI1 and EWSR1 loci, suggesting that an unbalanced t(11;22) and subsequent duplication of the derivative chromosome harboring fusion gene is a common event in ESFT. Further, amplifications on chromosomes 20 and 22 seen in one patient sample suggest a novel translocation type between EWSR1 and an unidentified fusion partner at 20q. In total 20 novel ESFT associated putative oncogenes and tumor suppressor genes were found in the integration analysis of array CGH and expression data. Quantitative RT-PCR to study the expression levels of the most interesting gene, HDGF, confirmed that its expression was higher than in control samples. However, no association between HDGF expression and patient survival was observed.ConclusionWe conclude that array CGH and integration analysis proved to be effective methods to identify chromosome regions and novel target genes involved in the tumorigenesis of ESFT.

Purpose: Osteosarcoma, the most common bone tumor, lacks prognostic markers that could distinguish patients before therapy and drive treatment choices.We assessed the prognostic value of CCN1, CCN2, and CCN3 genes, involved in fundamental biological processes. Experimental Design: Expression of CCN1, CCN2, and CCN3 was measured by quantitative PCR in 45 newly diagnosed osteosarcomas. Cancer-specific survival was estimated using the Kaplan-Meier method. Associations with osteoblastic differentiation and/or drug response genes were assessed in tumor cells using Spearman correlation and Fisher's exact tests. Results: CCN1 and CCN2 expression was associated with genes involved in commitment of mesenchymal stem cells toward osteoblasts and in early phases of osteoblastic differentiation (RUNX family genes; cadherin 4, 11, and 13; jun and fos; collagen I and SPARC). Although CCN3 is barely expressed in normal proliferating osteoblasts and mesenchymal stem cells, its expression was generally high in osteosarcoma and its level of expression did not correlate with any specific osteoblastic differentiation genes. High expression of CCN3 significantly correlated with worse prognosis in osteosarcoma. This may be only partly explained by the association with the expression of multidrug resistance^related protein 1and 4, two ATP-binding cassette transporters that also acted as predictors of worse outcome in our study. Conclusions: Our study showed temporal and coordinated expression of CCN1, CCN2, and CCN3 genes during osteoblastic differentiation and highlighted significant differences between human normal and osteosarcoma cell differentiation in vitro. CCN1 and CCN2 expression shows no prognostic relevance in osteosarcoma. In contrast, assessment for CCN3 expression levels at diagnosis may represent a useful molecular tool to early identification of patients with different prognosis.Osteosarcomas constitute a heterogeneous group of malignant neoplasms, the great majority of which are represented by high-grade tumors with advanced phenotypes at the time of diagnosis. In spite of their relatively low incidence, <10% of all tumors, these sarcomas represent a considerable burden because they are one of the most frequent pediatric bone tumors and remain prominent among both teenagers and young adults.Although new therapies that combine high-dose chemotherapy with local control of the tumor have led to a significant benefit in terms of patient survival (1, 2), there is a need for molecular prognostic markers that would permit, at the time of diagnosis, identification of poorly responsive tumors that may benefit from modified treatment regimen.To date, aside from metastasis at presentation, the other most accepted prognostic factors are based on the response to treatment (percentage of necrosis or P-glycoprotein expression). However, P-glycoprotein overexpression still suffers from an undisputed recognition as a prognostic factor (2 -4) and of lack of suitable drugs that are available for clinical practice, impairing its ...