Understanding Aberrant Signaling to Elude Therapy Escape Mechanisms in Myeloproliferative Neoplasms

Aberrant signaling in myeloproliferative neoplasms may arise from alterations in genes coding for signal transduction proteins or epigenetic regulators. Both mutated and normal cells cooperate, altering fragile balances in bone marrow niches and fueling persistent inflammation through paracrine or systemic signals. Despite the hopes placed in targeted therapies, myeloid proliferative neoplasms remain incurable diseases in patients not eligible for stem cell transplantation. Due to the emergence of drug resistance, patient management is often very difficult in the long term. Unexpected connections among signal transduction pathways highlighted in neoplastic cells suggest new strategies to overcome neoplastic cell adaptation.

Oral high-dose sucrosomial iron vs intravenous iron in sideropenic anemia patients intolerant/refractory to iron sulfate: a multicentric randomized study

Iron deficiency anemia is among the most frequent causes of disability. Intravenous iron is the quickest way to correct iron deficiency, bypassing the bottleneck of iron intestinal absorption, the only true mechanism of iron balance regulation in human body. Intravenous iron administration is suggested in patients who are refractory/intolerant to oral iron sulfate. However, the intravenous way of iron administration requires several precautions; as the in-hospital administration requires a resuscitation service, as imposed in Europe by the European Medicine Agency, it is very expensive and negatively affects patient's perceived quality of life. A new oral iron formulation, Sucrosomial iron, bypassing the normal way of absorption, seems to be cost-effective in correcting iron deficiency anemia at doses higher than those usually effective with other oral iron formulations. In this multicentric randomized study, we analyze the cost-effectiveness of intravenous sodium ferrigluconate vs oral Sucrosomial iron in patients with iron deficiency anemia refractory/intolerant to oral iron sulfate without other interfering factors on iron absorption.

Germline GATA2 variant disrupting endothelial eNOS cell function and angiogenesis can be restored by c-Jun/AP-1 upregulation

GATA2 is a transcription factor with key roles in hematopoiesis. Germline GATA2 gene variants have been associated with several inherited and acquired hematologic disorders, including myelodysplastic syndromes. Among the spectrum of GATA2 deficiency- associated manifestations thrombosis has been reported in 25% of patients, but the mechanisms are unknown. GATA2 was shown to be involved in endothelial nitric oxide synthase (eNOS) regulation and vascular development. We assessed eNOS expression and angiogenesis in patients with GATA2 deficiency. Platelets and blood outgrowth endothelial cells (BOEC) from GATA2 variant carriers showed impaired NO production and reduction of eNOS mRNA and protein expression and of eNOS activity. GATA2 binding to the eNOS gene was impaired in BOEC from GATA2-deficient patients, differently from control BOEC. GATA2 deficiency BOEC showed also defective angiogenesis, which was completely restored by treatment with the NO-donor Snitroso- N-acetylpenicillamine (SNAP). Atorvastatin, but not resveratrol, largely restored eNOS expression, NO biosynthesis and neoangiogenesis in GATA2-deficient BOEC by a mechanism involving increased expression of the eNOS transcription factor AP-1/c-JUN, replacing GATA2 when the latter is inactive. Our results unravel a possible thrombogenic mechanism of GATA2 mutations, definitely establish the regulation of eNOS by GATA2 in endothelial cells and show that endothelial angiogenesis is strictly dependent on the eNOS/NO axis. Given the ability of atorvastatin to restore NO production and angiogenesis by GATA2-deficient endothelial cells, the preventive effect of atorvastatin on thrombotic events and possibly on other clinical manifestations of the syndrome related to deranged angiogenesis should be explored in patients with GATA2 deficiency in an ad hoc designed clinical trial.

A novel mutation of indoleamine 2,3-dioxygenase 1 causes a rapid proteasomal degradation and compromises protein function

Indoleamine 2,3-dioxygenase 1 (IDO1) - the enzyme catalyzing the rate-limiting step of tryptophan catabolism along the kynurenine pathway - belongs to the class of inhibitory immune checkpoint molecules. Such regulators of the immune system are crucial for maintaining self-tolerance and thus, when properly working, preventing autoimmunity. A dysfunctional IDO1 has recently been associated with a specific single nucleotide polymorphism (SNP) and with the occurrence of autoimmune diabetes and multiple sclerosis. Many genetic alterations of IDO1 have been proposed being related with dysimmune disorders. However, the molecular and functional meaning of variations in IDO1 exomes as well as the promoter region remains a poorly explored field. In the present study, we identified a rare missense variant (rs751360195) at the IDO1 gene in a patient affected by coeliac disease, thyroiditis, and selective immunoglobulin A deficiency. Molecular and functional studies demonstrated that the substitution of lysine (K) at position 257 with a glutamic acid (E) results in an altered IDO1 protein that undergoes a rapid protein turnover. This genotype-to-phenotype relation is produced by peripheral blood mononuclear cells (PBMCs) of the patient bearing this variation and is associated with a specific phenotype (i.e., impaired tryptophan catabolism and defective mechanisms of immune tolerance). Thus decoding functional mutations of the IDO1 exome may provide clinically relevant information exploitable to personalize therapeutic interventions.

A distinct epigenetic program underlies the 1;7 translocation in myelodysplastic syndromes

The unbalanced translocation dic(1;7)(q10;p10) in myelodysplastic syndromes (MDS) is originated by centromeric juxtaposition resulting into 1q trisomy and 7q monosomy. More than half of cases arise after chemo/radio-therapy. To date, given the absence of genes within the centromeric regions, no specific molecular events have been identified in this cytogenetic subgroup. We performed the first comprehensive genetic and epigenetic analysis of MDS with dic(1;7)(q10;p10) compared to normal controls and therapy-related myeloid neoplasms (t-MNs). RNA-seq showed a unique downregulated signature in dic(1;7) cases, affecting more than 80% of differentially expressed genes. As revealed by pathway and gene ontology analyses, downregulation of ATP-binding cassette (ABC) transporters and lipid-related genes and upregulation of p53 signaling were the most relevant biological features of dic(1;7). Epigenetic supervised analysis revealed hypermethylation at intronic enhancers in the dicentric subgroup, in which low expression levels of enhancer putative target genes accounted for around 35% of the downregulated signature. Enrichment of Krüppel-like transcription factor binding sites emerged at enhancers. Furthermore, a specific hypermethylated pattern on 1q was found to underlie the hypo-expression of more than 50% of 1q-deregulated genes, despite trisomy. In summary, dic(1;7) in MDS establishes a specific transcriptional program driven by a unique epigenomic signature.

Lenalidomide treatment of myelodysplastic syndromes with chromosome 5q deletion: Results from the National Registry of the Italian Drug Agency

OBJECTIVE

The most typical cytogenetic aberration in myelodysplastic syndromes is del(5q), which, when isolated, is associated with refractory anaemia and good prognosis. Based on high rates of erythroid response and transfusion independence, Lenalidomide (LEN) became the standard treatment. This multi-centre study was designed to supplement Italian Registry data on LEN by addressing prescription, administration appropriateness, haematological and cytogenetic responses and disease evolution.

METHODS

MORE study was an observational, non-interventional, multi-centre, retrospective and prospective study. Cases were recruited from 45 Haematological Centres throughout Italy. Data were collected from the Italian National Registry for Lenalidomide administration and supplemented by a MORE data form.

RESULTS

Data from 190/213 patients were analysed. In all, 149 had been diagnosed by conventional cytogenetics (GROUP A) and 41 only by FISH (GROUP B). Overall erythroid response was obtained in 92.8% of cases. Overall cytogenetic remission was achieved in 22.6% of cases. Disease progression occurred in 15.6% of cases. Clonal cytogenetic evolution characterised progression to AML but not to higher risk MDS.

CONCLUSIONS

Erythroid response to Lenalidomide was similar in MDS with isolated del(5q) and with del(5q) plus one anomaly. Progression to AML or higher risk MDS showed different cytogenetic features.

Extension of the celiac intestinal antibody (CIA) pattern through eight antibody assessments in fecal supernatants from patients with celiac disease

BACKGROUND

Detection of anti-transglutaminase, anti-endomysium and anti-gliadin antibodies is commonly used to screen celiac disease patients. Besides that in serum, these antibodies are detectable in culture supernatants of oral, duodenal and colonic biopsy samples, saliva, gut lavage fluid samples, and fecal supernatants. Our aim was to extend the intestinal antibody pattern in fecal supernatants from patients with celiac disease.

METHODS

The fecal supernatants obtained from 25 celiac disease patients and 12 healthy volunteers were used to determine IgA and IgG1 anti-endomysium by immunofluorescence analysis, IgA and IgG anti-transglutaminase, IgA and IgG anti-deamidated gliadin peptides, IgA/IgG anti-transglutaminase/deamidated gliadin peptides and IgA anti-actin by enzyme-linked immunosorbent assay.

RESULTS

IgA anti-endomysium were found in 11 of 25 (44.0%) celiac disease patients and in none of healthy volunteers (p=0.0066). The levels of IgA anti-transglutaminase, IgA anti-deamidated gliadin peptides, IgA/IgG anti-transglutaminase/deamidated gliadin peptides and IgA anti-actin determined in celiac disease patients were significantly higher (p=0.0005, p=0.0018, p=0.0061 and p=0.0477, respectively) than those measured in healthy volunteers. The ROC curve analysis showed a diagnostic significance in IgA anti-transglutaminase (AUC=0.862, p<0.0001), IgA anti-deamidated gliadin peptides (AUC=0.822, p<0.0001) and IgA/IgG anti-transglutaminase/deamidated gliadin peptides (AUC=0.783, p=0.0003) fecal tests.

CONCLUSIONS

Our data extend the intestinal antibody pattern detectable in fecal supernatants, thus increasing the knowledge in the humoral immunity of celiac disease. Further studies are needed to better evaluate the role of fecal antibody tests in identifying celiac disease patients.