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Malignant peripheral nerve sheath tumors (MPNST) are rare, highly aggressive sarcomas that can occur spontaneously or from pre-existing plexiform neurofibromas in neurofibromatosis type1 (NF1) patients. MPNSTs have high local recurrence rates, metastasize easily, are generally resistant to therapeutic intervention and frequently fatal for the patient. Novel targeted therapeutic strategies are urgently needed. Standard treatment for patients presenting with advanced disease is doxorubicin based chemotherapy which inhibits the actions of the enzyme topoisomerase IIα (TOP2A). Recent molecular studies using murine models and cell lines identified the bromodomain containing protein 4 (BRD4) and enhancer of zeste homolog 2 (EZH2) as novel targets for MPNST treatment. We investigated the expression and potential use of BRD4, EZH2 and TOP2A as therapeutic targets in human NF1-derived MPNSTs. The transcript levels of BRD4, EZH2 and TOP2A were determined in paired formalin-fixed paraffin-embedded (FFPE) neurofibroma/MPNST samples derived from the same NF1 patient and in a set of plexiform neurofibromas, atypical neurofibromas and MPNST. We further examined the effect on cell viability of genetic or pharmacological inhibition of BRD4, EZH2 and TOP2A in an MPNST cell line panel. Our results indicated that in MPNST samples BRD4 mRNA levels were not upregulated and that MPNST cell lines were relatively insensitive to the bromodomain inhibitor JQ1. We corroborated that EZH2 mRNA expression is increased in MPNST but failed to confirm its reported pivotal role in MPNST pathogenesis as EZH2 knockdown by siRNA did not interfere with cellular proliferation and viability. Finally, the relation between TOP2A levels and sensitivity for doxorubicin was examined, confirming reports that TOP2A mRNA levels were overexpressed in MPNST and showing that MPNST cell lines exhibited relatively high TOP2A protein levels and sensitivity to doxorubicin. We tentatively conclude that the potential for effective therapeutic intervention in MPNST by targeting BRD4, EZH2 and TOP2A individually, may be limited. Clinical studies are necessary to ultimately prove the relevance of BRD4 and EZH2 inhibition as novel therapeutic strategies for MPNST.

Invasive Staphylococcus aureus infections are frequently associated with bacteraemia. To support clinical decisions on antibiotic therapy, there is an urgent need for reliable markers as predictors of infection outcome. In the present study in mice, bacteraemia was established by intravenous inoculation of a clinical S. aureus isolate at the LD50 inoculum. As potential biomarkers for fatal outcome, blood culture (qualitative and quantitative), serum levels of C-reactive protein (CRP), as well as 31 selected cytokines and chemokines were assessed during the first three days of infection. A positive S. aureus blood culture, the quantitative blood culture, CRP levels, and levels of eight cytokines were indicative for the presence of S. aureus bacteraemia. However, only tumor necrosis factor (TNF) α, interleukin (IL) 1α, and keratinocyte chemoattractant (KC; a functional homologue of human IL-8) were each significantly elevated in eventually non-surviving infected mice versus eventually surviving infected mice. In severe S. aureus bacteraemia in mice, TNF-α, IL-1α, and KC are biomarkers predicting fatal outcome of infection. KC was a biomarker elevated irrespective the progression of infection, which is very interesting regarding clinical application in view of the heterogeneity of patients experiencing bacteraemia in this respect.

Aims: Non-invasive measures of brain iron content would be of great benefit in neurodegeneration with brain iron accumulation (NBIA) to serve as a biomarker for disease progression and evaluation of iron chelation therapy. Although magnetic resonance imaging (MRI) provides several quantitative measures of brain iron content, none of these have been validated for patients with a severely increased cerebral iron burden. We aimed to validate R2* as a quantitative measure of brain iron content in aceruloplasminemia, the most severely iron-loaded NBIA phenotype. Methods: Tissue samples from 50 gray- and white matter regions of a postmortem aceruloplasminemia brain and control subject were scanned at 1.5 T to obtain R2*, and biochemically analyzed with inductively coupled plasma mass spectrometry. For gray matter samples of the aceruloplasminemia brain, sample R2* values were compared with postmortem in situ MRI data that had been obtained from the same subject at 3 T – in situ R2*. Relationships between R2* and tissue iron concentration were determined by linear regression analyses. Results: Median iron concentrations throughout the whole aceruloplasminemia brain were 10 to 15 times higher than in the control subject, and R2* was linearly associated with iron concentration. For gray matter samples of the aceruloplasminemia subject with an iron concentration up to 1000 mg/kg, 91% of variation in R2* could be explained by iron, and in situ R2* at 3 T and sample R2* at 1.5 T were highly correlated. For white matter regions of the aceruloplasminemia brain, 85% of variation in R2* could be explained by iron. Conclusions: R2* is highly sensitive to variations in iron concentration in the severely iron-loaded brain, and might be used as a non-invasive measure of brain iron content in aceruloplasminemia and potentially other NBIA disorders.