Clinical impact of miR-223 expression in pediatric T-Cell lymphoblastic lymphoma

Although probability of event-free survival in pediatric lymphoblastic T-cell lymphoma (T-LBL) is about 75%, survival in relapsed patients is very poor, so the identification of new molecular markers is crucial for treatment optimization. Here, we demonstrated that the over-expression of miR-223 promotes tumor T-LBL cell growth, migration and invasion in vitro. We found out that SIK1, an anti-metastatic protein, is a direct target of miR-223 and consequently is significantly reduced in miR-223-overexpressing tumor cells. We measured miR-223 expression levels at diagnosis in tumor biopsies from 67 T-LBL pediatric patients for whom complete clinical and follow up data were available, and we found that high miR-223 expression (above the median value) is associated with worse prognosis (PFS 66% vs 94%, P=0.0036). In addition, the multivariate analysis, conducted taking into account miR-223 expression level and other molecular and clinical characteristics, showed that only high level of miR-223 is an independent factor for worse prognosis. MiR-223 represents a promising marker for treatment stratification in pediatric patients with T-LBL and we provide the first evidence of miR-223 potential role as oncomir by SIK1 repression.

Kinetics of Circulating Plasma Cell-Free DNA in Paediatric Classical Hodgkin Lymphoma

Levels of plasma cell-free DNA (cfDNA) of a large series of children with classical Hodgkin lymphoma (cHL) were evaluated and analyzed at diagnosis and during chemotherapy treatment in relation with clinical characteristics. CfDNA levels in cHL patients were significantly higher compared with controls (p=0.002). CfDNA at diagnosis was correlated with presence of B symptoms (p=0.027) and high erythrocyte sedimentation rate (p=0.049). We found that the increasing of plasma cfDNA after first chemotherapy cycle seems to be associated with a worse prognosis (p=0.049). Levels of plasma cfDNA might constitute an interesting non-invasive tool in cHL patients' management.

Plasma membrane calcium ATPases and related disorders

The plasma membrane Ca(2+) ATPases (PMCA pumps) cooperate with other transport systems in the plasma membrane and in the organelles in the regulation of cell Ca(2+). They have high Ca(2+) affinity and are thus the fine tuners of cytosolic Ca(2+). They belong to the superfamily of P-type ATPases: their four basic isoforms share the essential properties of the reaction cycle and the general membrane topography motif of 10 transmembrane domains and three large cytosolic units. However they also differ in other important properties, e.g., tissue distribution and regulatory mechanisms. Their chief regulator is calmodulin, that removes their C-terminal cytosolic tail from autoinhibitory binding sites next to the active site of the pump, restoring activity. The number of pump isoforms is increased to over 30 by alternative splicing of the transcripts at a N-terminal site (site A) and at site C within the C-terminal calmodulin binding domain: the splice variants are tissue specific and developmentally regulated. The importance of PMCAs in the maintenance of cellular Ca(2+) homeostasis is underlined by the disease phenotypes, genetic or acquired, caused by their malfunction. Non-genetic PMCA deficiencies have long been considered possible causative factors in disease conditions as important as cancer, hypertension, or neurodegeneration. Those of genetic origin are better characterized: some have now been discovered in humans as well. They concern all four PMCA isoforms, and range from cardiac dysfunctions, to deafness, to hypertension, to cerebellar ataxia.