Hereditary Haemorrhagic Telangiectasia (HHT) Marked by ACVRL1C1120T Variant Displays Hypopigmented Naevi and Frequent Bleeding Episodes if CYP2C9 Co-Mutated: Clinical Notes & Rationale of Patient Registry.

Hereditary haemorrhagic telangiectasia (HHT) exhibits considerable phenotypic heterogeneity. Therefore, precise mutation screening and evaluation of patient risk must be determined in every HHT family. We present an HHT-2 case with an initial life-threatening bleeding episode that led to identification of a relatively large HHT family. Exome sequencing of the family members determined HHT-associated ACVRL1C1120T variant resulting in Arg374Trp substitution at the Ser/Thr-kinase domain region. The affected members display typical epistaxis symptomatology from early childhood resulting in sideropoenia. In addition, the HHT patients also displayed dermatology findings such as facial teleangiectasias and trunk/limb white spots representing post-inflammatory hypopigmentation. Interestingly, co-segregating with modifying cytochrome P450 (CYP2C) variant in the HHT patients led to NSAID intolerance marked by increased frequency of bleeding episodes. No arterial-venous malformation of the visceral organs and brain or association with cancer were observed. The heterogeneity of clinical presentation and the role of other variants support the need of regular patient monitoring and development of a nation-wide patient registry.

Modeling cancer driver events in vitro using barrier bypass-clonal expansion assays and massively parallel sequencing.

The information on candidate cancer driver alterations available from public databases is often descriptive and of limited mechanistic insight, which poses difficulties for reliable distinction between true driver and passenger events. To address this challenge, we performed in-depth analysis of whole-exome sequencing data from cell lines generated by a barrier bypass-clonal expansion (BBCE) protocol. The employed strategy is based on carcinogen-driven immortalization of primary mouse embryonic fibroblasts and recapitulates early steps of cell transformation. Among the mutated genes were almost 200 COSMIC Cancer Gene Census genes, many of which were recurrently affected in the set of 25 immortalized cell lines. The alterations affected pathways regulating DNA damage response and repair, transcription and chromatin structure, cell cycle and cell death, as well as developmental pathways. The functional impact of the mutations was strongly supported by the manifestation of several known cancer hotspot mutations among the identified alterations. We identified a new set of genes encoding subunits of the BAF chromatin remodeling complex that exhibited Ras-mediated dependence on PRC2 histone methyltransferase activity, a finding that is similar to what has been observed for other BAF subunits in cancer cells. Among the affected BAF complex subunits, we determined Smarcd2 and Smarcc1 as putative driver candidates not yet fully identified by large-scale cancer genome sequencing projects. In addition, Ep400 displayed characteristics of a driver gene in that it showed a mutually exclusive mutation pattern when compared with mutations in the Trrap subunit of the TIP60 complex, both in the cell line panel and in a human tumor data set. We propose that the information generated by deep sequencing of the BBCE cell lines coupled with phenotypic analysis of the mutant cells can yield mechanistic insights into driver events relevant to human cancer development.

Association of Low Ficolin-Lectin Pathway Parameters with Cardiac Syndrome X.

In patients with typical angina pectoris, inducible myocardial ischaemia and macroscopically normal coronaries (cardiac syndrome X (CSX)), a significantly elevated plasma level of terminal complement complex (TCC), the common end product of complement activation, has been observed without accompanying activation of the classical or the alternative pathways. Therefore, our aim was to clarify the role of the ficolin-lectin pathway in CSX. Eighteen patients with CSX, 37 stable angina patients with significant coronary stenosis (CHD) and 54 healthy volunteers (HC) were enrolled. Serum levels of ficolin-2 and ficolin-3, ficolin-3/MASP-2 complex and ficolin-3-mediated TCC deposition (FCN3-TCC) were determined. Plasma level of TCC was significantly higher in the CSX than in the HC or CHD group (5.45 versus 1.30 versus 2.04 AU/ml, P < 0.001). Serum levels of ficolin-2 and ficolin-3 were significantly lower in the CSX compared to the HC or CHD group (3.60 versus 5.80 or 5.20 µg/ml, P < 0.05; 17.80 versus 24.10 or 26.80 µg/ml, P < 0.05). The ficolin-3/MASP-2 complex was significantly lower in the CSX group compared to the HC group (92.90 versus 144.90 AU/ml, P = 0.006). FCN3-TCC deposition was significantly lower in the CSX group compared to the HC and CHD groups (67.8% versus 143.3% or 159.7%, P < 0.05). In the CSX group, a significant correlation was found between TCC and FCN3-TCC level (r = 0.507, P = 0.032) and between ficolin-3/MASP-2 complex level and FCN3-TCC deposition (r = 0.651, P = 0.003). In conclusion, in patients with typical angina and myocardial ischaemia despite macroscopically normal coronary arteries, low levels of several lectin pathway parameters were observed, indicating complement activation and consumption. Complement activation through the ficolin-lectin pathway might play a role in the complex pathomechanism of CSX.

Aggressive acute myeloid leukemia in PU.1/p53 double-mutant mice.

PU.1 downregulation within hematopoietic stem and progenitor cells (HSPCs) is the primary mechanism for the development of acute myeloid leukemia (AML) in mice with homozygous deletion of the upstream regulatory element (URE) of PU.1 gene. p53 is a well-known tumor suppressor that is often mutated in human hematologic malignancies including AML and adds to their aggressiveness; however, its genetic deletion does not cause AML in mouse. Deletion of p53 in the PU.1(ure/ure) mice (PU.1(ure/ure)p53(-/-)) results in more aggressive AML with shortened overall survival. PU.1(ure/ure)p53(-/-) progenitors express significantly lower PU.1 levels. In addition to URE deletion we searched for other mechanisms that in the absence of p53 contribute to decreased PU.1 levels in PU.1(ure/ure)p53(-/-) mice. We found involvement of Myb and miR-155 in downregulation of PU.1 in aggressive murine AML. Upon inhibition of either Myb or miR-155 in vitro the AML progenitors restore PU.1 levels and lose leukemic cell growth similarly to PU.1 rescue. The MYB/miR-155/PU.1 axis is a target of p53 and is activated early after p53 loss as indicated by transient p53 knockdown. Furthermore, deregulation of both MYB and miR-155 coupled with PU.1 downregulation was observed in human AML, suggesting that MYB/miR-155/PU.1 mechanism may be involved in the pathogenesis of AML and its aggressiveness characterized by p53 mutation.

5-azacitidine in aggressive myelodysplastic syndromes regulates chromatin structure at PU.1 gene and cell differentiation capacity.

Epigenetic 5-azacitidine (AZA) therapy of high-risk myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML) represents a promising, albeit not fully understood, approach. Hematopoietic transcription factor PU.1 is dynamically regulated by upstream regulatory element (URE), whose deletion causes downregulation of PU.1 leading to AML in mouse. In this study a significant group of the high-risk MDS patients, as well as MDS cell lines, displayed downregulation of PU.1 expression within CD34+ cells, which was associated with DNA methylation of the URE. AZA treatment in vitro significantly demethylated URE, leading to upregulation of PU.1 followed by derepression of its transcriptional targets and onset of myeloid differentiation. Addition of colony-stimulating factors (CSFs; granulocyte-CSF, granulocyte-macrophage-CSF and macrophage-CSF) modulated AZA-mediated effects on reprogramming of histone modifications at the URE and cell differentiation outcome. Our data collectively support the importance of modifying the URE chromatin structure as a regulatory mechanism of AZA-mediated activation of PU.1 and induction of the myeloid program in MDS.

Circulating endothelial cell count, plasma vWF and soluble ICAM-1 levels following primary or elective percutaneous coronary intervention.

BACKGROUND: Percutaneous coronary intervention (PCI) is an important therapeutic strategy in patients with ischaemic heart disease. Our aim was to clarify the extent of endothelial injury induced by PCI in stable angina (SA) or in acute ST-elevation myocardial infarction (STEMI). METHODS: Circulating endothelial cell (CEC) count, von Willebrand factor (vWF) and soluble intercellular adhesion molecule-1 (sICAM-1) levels were determined pre-, post-, 24 and 96h after PCI in patients with SA (n=23) and with STEMI (n=28). To provide control data regarding the effect of angiography itself stable angina patients with coronarography only (n=23) were enrolled. RESULTS: PCI and coronarography in stable angina patients caused measurable, but only non-significant elevation of CEC count and plasma vWF (p=NS). In STEMI, significantly higher baseline CEC count (p=0.019) and vWF plasma levels (p=0.046) were found compared to SA with PCI/or coronarography. After PCI, explicit increase in CEC count was observed (significant peak at 24h) (p=0.036). Positive correlation was found between baseline CKMB and CEC count at 24h (r=0.51, p<0.05). CONCLUSION: Both coronary angiography and elective PCI cause only mild endothelial injury. However, in patients with STEMI, not only the procedure itself but myocardial ischemia and the ongoing atherothrombotic process might be responsible for the prolonged and more pronounced endothelial damage.

[Growth and puberty in children after treatment of acute lymphoblastic leukemia]. / Rast a puberta u detí po liecbe akútnej lymfoblastickej leukémie.

BACKGROUND: Growth retardation and other endocrine abnormalities were recognized as sequelae of therapy of acute lymphoblastic leukemia (ALL), especially when chemotherapy was combined with cranial irradiation. The aim of our study was to establish growth and pubertal development in the group of children who had been previously successfully treated for ALL. METHODS AND RESULTS: 58 children (30 F, 28 M, age 8-18 y.) in complete initial remission lasting 4-15 y. (m 8 y.) after standard antileukemic therapy (including cranial irradiation) completed 2-9 y. ago (m 3 including y.) were studied. Standard deviation score (SDS) of standing height (SH) to chronological age (CA) and to genetic target height (GTH), index of body proportionality and timing of puberty were followed up. The final height attained 21 girls and 3 boys. The height of the boys differed neither from the average for our men, nor from their GTH. Girls: SH 148 cm-169 cm, SH of 7 girls > or = -1.5 SDS, 8 girls > or = -1.5 SDS to their GTH. The final height didn't reach yet 23 boys and 9 girls. Their SH to CA as well as SH to GTH didn't substantially differ from average. Index of body proportionality > or = 1.5 SDS in 12/30 girls and 6/28 boys. Menarche was already reached in 25 girls in age ranging from 10-15 y. (mean 11.3 y.), what was less than average for our population (13.3 y.). CONCLUSION: Even the height of prepubertal children under study didn't differ from average, the final height of girls (boys could not be evaluated because of small numbers) was significantly lower as could be expected. We suppose the early ending of puberty as a contributing factor of short stature in girls. Clear tendency to obesity especially among older girls was observed. Children who underwent antileukemic therapy deserve careful endocrinological follow-up.