Our study provides further evidence of the critical role played by folate pathway enzymes in the outcome of ALL, possibly through the interference of MTX.

BackgroundEnhancer of Zeste Drosophila Homologue 2 (EZH2) is a key regulator of transcription as a member of polycomb repressive complex 2 (PRC2) which exerts repression of downstream genes and is correlated to invasiveness and progression of different tumours. Therefore, we evaluated the expression of PRC2 proteins in pediatric soft tissue sarcoma (rhabdomyosarcoma, RMS and extraosseous Ewing sarcoma, EES) correlating them to the clinical outcome of the patients.MethodsWe analyzed PRC2 protein expression by quantitative real time PCR, western blotting and immunohistochemistry in 17 soft tissue sarcomas (11 RMS and 6 EES) enrolled at Paediatric Oncology Units of the Second University of Naples. Expression analysis was performed for EZH2, SUZ12 and EED.ResultsEnhancer of Zeste Drosophila Homologue 2 was expressed with a different degree in 60 % of samples. Interestingly, the magnitude of EZH2 up regulation was significantly higher in patients presenting lymph node and/or distant metastases at the diagnosis. Moreover, patients overexpressing EZH2 had a lower probability of survival compared to patients negative or with low EZH2 expression.ConclusionsOur study suggests that high EZH2 expression is associated to increased aggressiveness of the disease. Therefore, drugs that control its activity could be potentially used in the epigenetic target treatment of tumors with these alterations.

Neuroblastoma (NB) is a paediatric tumor that arises from neural crest and shows heterogeneous clinical and biological features. The serine-protease high temperature requirement A1 (HtrA1) has a pivotal role in both cell proliferation and differentiation. Here we report the expression and localization of HtrA1 in NB tumor samples to assess HtrA1 role as a possible new biomarker of cellular differentiation in NB patients. HtrA1 protein expression by Western Blot assay was performed in 60 tissue samples of 50 children with NB and 10 children with ganglioneuroblastoma (GNB). HtrA1 was expressed in 56/60 (93.3 %) samples with different expression levels: low levels in 36/56 samples (64.3 %) and high levels in 20/56 (35.7 %). Higher levels were found in 1, 2 and 4s stages (80 %), whereas 3 and 4 stages (20 %) showed a low expression, with a statistically significant difference (p = 0.003). Among not amplified N-MYC group, 28 (60 %) had low/absent expression of HtrA1: seven with recurrent disease and negative outcome and 21 in continuous complete remission (CCR), whereas all samples with high expression of HtrA1 (17/44) were in CCR (p = 0.03). The immunohistochemical analysis showed localization of HtrA1 in differentiated areas higher than in undifferentiated areas where the protein was absent. Moreover, HtrA1 was highly expressed in all GNB samples. In conclusion, the over-expression of HtrA1 is correlated to cellular differentiation grade and stage of NB at diagnosis. Moreover, HtrA1 could represent a new marker of undifferentiation and biological aggressiveness of NB.

BackgroundT-cell Acute Lymphoblastic Leukemia (ALL) represents about 10–15 % of pediatric ALL cases. EZH2, one of the components of Polycomb group proteins (PRC2) complex, catalyzes the trimethylation of histone H3 lysine 27 that is associated with transcriptional repression and tumor development.MethodsWe examined the expression levels of PRC2 complex in primary samples of T cells ALL at diagnosis by western blotting and real time PCR. We evaluated the effect of 3-deazaneplanocin-A (DZNep), an EZH2 inhibitor, alone and in combination with Daunoblastine on cell viability, apoptotic death and cell cycle distribution of T cell established Jurkat cell line.ResultsEZH2 was expressed in 75 % samples at different extents mainly with high expression level. SUZ12 was expressed in 60 % samples and EED in all samples, respectively. The Kaplan-Meier analysis shows that T-ALL expressing EZH2 had a lower probability of disease-free survival (DFS) compared to T-ALL negative for EZH2 (23 % vs 100 %) (p = 0.01). The EZH2 inhibitor DZNep used in combination with Daunoblastine was synergistic in inducing growth inhibition and increasing the apoptosis in T-ALL Jurkat cells at 48 and 72 h paralleled by EZH2 decreased expression. Moreover, the combination decreased the activity of Erk-1/2 proliferation enzymes with no effects on Akt survival pathway.ConclusionsThe evaluation of EZH2 expression in pediatric T-ALL can be useful in predict the clinical outcome of the patients and EZH2 can be a useful target to improve the efficacy of conventional chemotherapy in this subset of patients with bad prognosis.

High-dose methotrexate (MTX) is a key component of most treatment protocols for childhood and adolescent non-Hodgkin lymphoma (NHL). Recent studies have suggested that the toxicity of antifolate drugs, such as MTX, is affected by inherited single nucleotide polymorphisms (SNPs) in folate metabolizing genes. The aim of our study was to investigate the potential influence of the C677T and A1298C genetic variants of the methylenetetrahydrofolate reductase (MTHFR) gene on the clinical toxicity and efficacy of MTX in pediatric patients with NHL (n = 95) treated with therapeutic protocols Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) LNH-97 and EURO LB-02. We demonstrated that patients with the 677T genotype had an approximately six-fold greater risk of developing hematological toxicity compared with wild-type carriers, especially in the 1 g/m(2) treatment group (p = 0.01). Moreover, we identified a correlation between the risk of relapse and the T genotype: T carriers had reduced disease-free survival compared with wild-type patients (67% vs. 100%). Our data suggest a pharmacogenetic influence on the adverse effects of high-dose MTX in the 1 g/m(2) treatment group.

Manganese superoxide dismutase (MnSOD) is a mitochondrial enzyme that defends against oxidative damage due to reactive oxygen species (ROS). A new isoform of MnSOD with cytotoxic activity was recently discovered in liposarcoma cells. Here, we tested the effectiveness of a recombinant form of this isoform (rMnSOD) on leukemic T cells, Jurkat cells, and lymphocytes. Our results confirm that leukemic T cells can internalize rMnSOD and that rMnSOD causes apoptosis of 99% of leukemic cells without showing toxic effects on healthy cells. Using light and electron microscopy, we determined that an rMnSOD concentration of 0.067 μM most effective on apoptosis induction. Western blot analysis showed that treatment with 0.067 μM rMnSOD resulted in high expression of the pro-apoptotic protein Bax and low expression of the anti-apoptotic protein Bcl-2 in leukemia cells. Concerning signal transduction pathway no influence was observed after treatment except for Jurkat cells showing a slightly decreased expression of ERK phosphorylation. These results suggest that rMnSOD may be an effective and non-toxic treatment option for T-cell leukemia.

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