Purpose: Ewing tumor cell survival and proliferation depends on several autocrine loops. Targeting these loops is a promising therapeutic approach. We recently showed the cytostatic role of imatinib, an inhibitor of the SCF-KIT loop, on Ewing tumor cells, and in this study, we intend to analyze the inhibition of the insulin-like growth factor I receptor (IGF1R) loop. Experimental Design: We analyzed IGF1R blockade by ADW742, a small molecule specific for this receptor, alone and in combination with imatinib, vincristine, and doxorubicin on Ewing tumor cell lines. We studied the effect on proliferation, apoptosis, cell cycle, pathway phosphorylation, soft-agar growth, motility, and vascular endothelial growth factor expression levels. Results: Treatment with ADW742 induced down-regulation of IGF1R/AKT/mammalian target of rapamycin (mTOR) phosphorylation, which was deeper in cell lines having higher IGF1R activation levels. Treatment also induced dose-dependent inhibition of cell proliferation (IC 50 = 0.55-1.4 Amol/L), inducing a G 1 phase blockage and apoptosis. Addition of imatinib to ADW742 synergistically augmented these effects and was especially effective in inhibiting AKT/mTOR phosphorylation and reducing vascular endothelial growth factor expression in cell lines having high IGF1R activation levels. Combination with usual chemotherapeutic agents vincristine and doxorubicin showed synergistic interactions. Conclusions: Inhibition of Ewing tumor cell proliferation byADW742 is mediated through blockade of IGF1R signaling. Combination of ADW742 with imatinib, vincristine, and doxorubicin induces a significant reduction of tumor cell growth, mainly by the increase in apoptosis with a pattern depending on IGF1R activation levels.This study supports a potential role forADW742 in the treatment of Ewing tumor and AKT/mTOR as a possible surrogate marker of response to therapy.

PurposeTo differentiate the plasma metabolomic profile of patients with age related macular degeneration (AMD) from that of controls, by Nuclear Magnetic Resonance (NMR) spectroscopy.MethodsTwo cohorts (total of 396 subjects) representative of central Portugal and Boston, USA phenotypes were studied. For each cohort, subjects were grouped according to AMD stage (early, intermediate and late). Multivariate analysis of plasma NMR spectra was performed, followed by signal integration and univariate analysis.ResultsSmall changes were detected in the levels of some amino acids, organic acids, dimethyl sulfone and specific lipid moieties, thus providing some biochemical information on the disease. The possible confounding effects of gender, smoking history and age were assessed in each cohort and found to be minimal when compared to that of the disease. A similar observation was noted in relation to age-related comorbidities. Furthermore, partially distinct putative AMD metabolite fingerprints were noted for the two cohorts studied, reflecting the importance of nutritional and other lifestyle habits in determining AMD metabolic response and potential biomarker fingerprints. Notably, some of the metabolite changes detected were noted as potentially differentiating controls from patients diagnosed with early AMD.ConclusionFor the first time, this study showed metabolite changes in the plasma of patients with AMD as compared to controls, using NMR. Geographical origins were seen to affect AMD patients´ metabolic profile and some metabolites were found to be valuable in potentially differentiating controls from early stage AMD patients. Metabolomics has the potential of identifying biomarkers for AMD, and further work in this area is warranted.

BACKGROUND: Ewing sarcoma is a paradigm of solid tumour -bearing chromosomal translocations resulting in fusion proteins that act as deregulated transcription factors. Ewing sarcoma translocations fuse the EWS gene with an ETS transcription factor, mainly FLI1. Most of the EWS -FLI1 target genes still remain unknown and many have been identified in heterologous model systems. METHODS: We have developed a stable RNA interference model knocking down EWS -FLI1 in the Ewing sarcoma cell line TC71. Gene expression analyses were performed to study the effect of RNA interference on the genetic signature of EWS -FLI1 and to identify genes that could contribute to tumourigenesis. RESULTS: EWS -FLI1 inhibition induced apoptosis, reduced cell migratory and tumourigenic capacities, and caused reduction in tumour growth. IGF-1 was downregulated and the IGF-1/IGF-1R signalling pathway was impaired. PBK/TOPK (T-LAK cell-originated protein kinase) expression was decreased because of EWS -FLI1 inhibition. We showed that TOPK is a new target gene of EWS -FLI1. TOPK inhibition prompted a decrease in the proliferation rate and a dramatic change in the cell's ability to grow in coalescence. CONCLUSION: This is the first report of TOPK activity in Ewing sarcoma and suggests a significant role of this MAPKK-like protein kinase in the Ewing sarcoma biology.

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Ewing Sarcoma (ES) shows several deregulated autocrine loops mediating cell survival and proliferation. Therefore, their blockade is a promising therapeutic approach. We previously reported the in vitro effect of insulin-like growth factor 1 receptor (IGF1R)/KIT pathway blockade on ES cell lines, and we now extend our observations to changes induced by this treatment in interacting proteins/networks. A proteomic analysis revealed that Heat Shock Protein (HSP)90 was differentially expressed between ES cell lines sensitive and resistant to specific IGF1R/KIT inhibitors. We therefore inhibited HSP90 with 17-allylamino-17-demethoxygeldanamycin (17-AAG) and siRNA, and observed that ES cell line growth and survival were reduced, especially in the resistant cell lines. Conversely, HSP90 induced-expression conferred resistance to anti-IGF1R/KIT treatment in the sensitive cell lines. 17-AAG treatment induced HSP90 client protein degradation, including AKT, KIT, or IGF1R, by inhibiting their physical interaction with HSP90. Xenograft models developed with A673 ES cell line confirmed that HSP90 inhibition, alone or combined with IGF1R inhibition, significantly reduced tumor growth and expression of client proteins. Remarkably, using two independent clinical sample sets, we have found that nearly half of IGF1R-positive tumors also show HSP90 overexpression. This delineates a subset of patients that could benefit from combination of anti-HSP90 agents when considering IGF1R-targeting therapies. Importantly, sensitivity to drugs such as ADW/IMA depends not only on the levels of expression and basal activation of IGF1R/KIT, but also, and for the first time reported in ES, on the development of the stress response mechanism. Accordingly, HSP90 expression could be a predictive factor of response to IGF1R-targeting therapies. [Cancer Res 2008;68(15):6260-70]