Inhibition of protein kinase CK2 with the clinical-grade small ATP-competitive compound CX-4945 or by RNA interference unveils its role in acute myeloid leukemia cell survival,p53-dependent apoptosis and daunorubicin-induced cytotoxicity

Background

The involvement of protein kinase CK2 in sustaining cancer cell survival could have implications also in the resistance to conventional and unconventional therapies. Moreover, CK2 role in blood tumors is rapidly emerging and this kinase has been recognized as a potential therapeutic target. Phase I clinical trials with the oral small ATP-competitive CK2 inhibitor CX-4945 are currently ongoing in solid tumors and multiple myeloma.

Methods

We have analyzed the expression of CK2 in acute myeloid leukemia and its function in cell growth and in the response to the chemotherapeutic agent daunorubicin We employed acute myeloid leukemia cell lines and primary blasts from patients grouped according to the European LeukemiaNet risk classification. Cell survival, apoptosis and sensitivity to daunorubicin were assessed by different means. p53-dependent CK2-inhibition-induced apoptosis was investigated in p53 wild-type and mutant cells.

Results

CK2α was found highly expressed in the majority of samples across the different acute myeloid leukemia prognostic subgroups as compared to normal CD34⁺ hematopoietic and bone marrow cells. Inhibition of CK2 with CX-4945, K27 or siRNAs caused a p53-dependent acute myeloid leukemia cell apoptosis. CK2 inhibition was associated with a synergistic increase of the cytotoxic effects of daunorubicin. Baseline and daunorubicin-induced STAT3 activation was hampered upon CK2 blockade.

Conclusions

These results suggest that CK2 is over expressed across the different acute myeloid leukemia subsets and acts as an important regulator of acute myeloid leukemia cell survival. CK2 negative regulation of the protein levels of tumor suppressor p53 and activation of the STAT3 anti-apoptotic pathway might antagonize apoptosis and could be involved in acute myeloid leukemia cell resistance to daunorubicin.

     

Polymorphisms within the Novel Type 2 Diabetes Risk Locus MTNR1B Determine β-Cell Function

Background

Very recently, a novel type 2 diabetes risk gene, i.e., MTNR1B, was identified and reported to affect fasting glycemia. Using our thoroughly phenotyped cohort of subjects at an increased risk for type 2 diabetes, we assessed the association of common genetic variation within the MTNR1B locus with obesity and prediabetes traits, namely impaired insulin secretion and insulin resistance.

Methodology/Principal Findings

We genotyped 1,578 non-diabetic subjects, metabolically characterized by oral glucose tolerance test, for five tagging single nucleotide polymorphisms (SNPs) covering 100% of common genetic variation (minor allele frequency >0.05) within the MTNR1B locus (rs10830962, rs4753426, rs12804291, rs10830963, rs3781638). In a subgroup (N = 513), insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp, and in a further subgroup (N = 301), glucose-stimulated insulin secretion was determined by intravenous glucose tolerance test. After appropriate adjustment for confounding variables and Bonferroni correction for multiple comparisons, none of the tagging SNPs was reliably associated with measures of adiposity. SNPs rs10830962, rs4753426, and rs10830963 were significantly associated with higher fasting plasma glucose concentrations (p<0.0001) and reduced OGTT- and IVGTT-induced insulin release (p≤0.0007 and p≤0.01, respectively). By contrast, SNP rs3781638 displayed significant association with lower fasting plasma glucose levels and increased OGTT-induced insulin release (p<0.0001 and p≤0.0002, respectively). Moreover, SNP rs3781638 revealed significant association with elevated fasting- and OGTT-derived insulin sensitivity (p≤0.0021). None of the MTNR1B tagging SNPs altered proinsulin-to-insulin conversion.

Conclusions/Significance

In conclusion, common genetic variation within MTNR1B determines glucose-stimulated insulin secretion and plasma glucose concentrations. Their impact on β-cell function might represent the prevailing pathomechanism how MTNR1B variants increase the type 2 diabetes risk.     

Homonuclear and heteronuclear transition metal complexes by syn-proportionation reactions

Redox processes consisting of disproportionation and syn-proportionation are reviewed with special attention to metal complexes containing carbon-based ligands, i.e. carbon monoxide or unsaturated hydrocarbons. An introduction and a survey of reactions aimed to show the large applicability of syn-proportionation reactions in the field of coordination chemistry, is followed by examples of the use of these redox processes for the preparation of catalytic precursors. The latter studies derive from the idea that if a syn-proportionation reaction can be carried out between two complexes containing different metals in different oxidation states, inter-metallic systems could be formed which may act as active catalysts, e.g. for polymerization reactions.     

An Ultrastructural Investigation on Vitellophage Invasion of the Yolk Mass during and after Germ Band Formation in Embryos of the Stick Insect Carausius morosus Br.

Developing embryos of the stick insect Carausius morosus were examined ultrastructurally with a view to studying vitellophage invasion of the yolk mass during and after germ band formation. Newly laid eggs in C.morosus have a unique yolk fluid compartment surrounded by a narrow fringe of cytoplasm comprising several small yolk granules. Vitellophages originate mainly from a thin layer of stem cells, the so-called yolk cell membrane, interposed between the germ band and the yolk mass. Throughout development, a thin basal lamina separates the yolk cell membrane from the overlying embryo.
Vitellophages extend from the yolk cell membrane with long cytoplasmic processes or filopodia to invade the central yolk mass. Along their route of entrance, filopodia engulf portions of the yolk mass and sequester it into membrane-bounded granules. As this process continues, the yolk mass is gradually partitioned into a number of yolk granules inside the vitellophages.
Later in development, the yolk cell membrane is gradually replaced by the endodermal cells that emerge from the anterior and posterior embryonic rudiments. From this stage of development onwards, vitellophages remain attached to the basal lamina through long filopodia extending between the endodermal cells. Yolk confined in different vitellophagic cells appears heterogeneous both in density and texture, suggesting that yolk degradation may be spatially differentiated.     

Regulation of insulin-like growth factors I and II and their binding proteins in human bone marrow stromal cells by dexamethasone

Glucocorticoids inhibit the proliferation, but induce the differentiation, of bone marrow stromal cells into osteoblast-like cells. The mechanisms, however, are still conjectural. Since insulin-like growth factors (IGFs) have profound effects on osteoblast growth and differentiation, it is possible that glucocorticoids exert their effects on bone marrow stromal cells in part via regulation of IGFs. Therefore, we analyzed the effects of dexamethasone (Dex) on the expression of IGF I and IGF II in cultured preosteoblastic normal human bone marrow stromal cells (HBMSC). Whereas Dex decreased the concentration of IGF I in the conditioned medium since early in the treatment, the concentration of IGF II was increased progressively as culture period lengthened. As the activities of IGF I and IGF II are regulated by the IGF binding proteins (IGFBPs), we analyzed the effects of Dex on the expression of IGFBPs. Dex increased IGFBP-2 in a time-dependent manner. The increase in IGFBP-2, however, was only to the same extent as that of IGF II at most, depending on the length of treatment. Therefore, the increase in IGFBP-2 would dampen, but not eliminate, the increased IGF II activities. By contrast, Dex decreased IGFBP-3 levels, the latter increasing the bioavailability of IGF II. Although IGFBP-4 mRNA levels were stimulated by Dex, IGFBP-4 concentration in the conditioned medium was unchanged as measured by RIA. IGFBP-5 and IGFBP-6 mRNA levels were decreased by Dex in a time-dependent fashion. IGFBP-5 protein level was also decreased 1–4 days after Dex treatment. IGFBP-1 mRNA was not detectable in HBMSC. These accumulated data indicate that Dex regulates IGF I and IGF II and their binding proteins differentially in normal human bone marrow stromal cells. The progressive increase in IGF II may contribute to Dex-induced cell differentiation. J. Cell. Biochem. 71:449–458, 1998. © 1998 Wiley-Liss, Inc.     

Reconstruction of the Evolutionary Dynamics of A(H3N2) Influenza Viruses Circulating in Italy from 2004 to 2012

Background

Influenza A viruses are characterised by their rapid evolution, and the appearance of point mutations in the viral hemagglutinin (HA) domain causes seasonal epidemics. The A(H3N2) virus has higher mutation rate than the A(H1N1) virus. The aim of this study was to reconstruct the evolutionary dynamics of the A(H3N2) viruses circulating in Italy between 2004 and 2012 in the light of the forces driving viral evolution.

Methods

Phylodinamic analyses were made using a Bayesian method, and codon-specific positive selection acting on the HA coding sequence was evaluated.

Results

Global and local phylogenetic analyses showed that the Italian strains collected between 2004 and 2012 grouped into five significant Italian clades that included viral sequences circulating in different epidemic seasons. The time of the most recent common ancestor (tMRCA) of the tree root was between May and December 2003. The tMRCA estimates of the major clades suggest that the origin of a new viral strain precedes the effective circulation of the strain in the Italian population by 6–31 months, thus supporting a central role of global migration in seeding the epidemics in Italy. The study of selection pressure showed that four codons were under positive selection, three of which were located in antigenic sites. Analysis of population dynamics showed the alternation of periods of exponential growth followed by a decrease in the effective number of infections corresponding to epidemic and inter-epidemic seasons.

Conclusions

Our analyses suggest that a complex interaction between the immune status of the population, migrations, and a few selective sweeps drive the influenza A(H3N2) virus evolution. Our findings suggest the possibility of the year-round survival of local strains even in temperate zones, a hypothesis that warrants further investigation.     

Morpho-agronomic and molecular characterisation of oil palm Elaeis guineensis Jacq. material from Angola

The characterisation of phytogenetic resources is used to improve conservation strategies, promote new sources of plant material, and design breeding strategies. In this study, we evaluated oil palm material with nine morpho-agronomic traits and 30 microsatellite markers (Simple Sequence Repeats; SSRs) that had been previously collected in five geographical regions of Angola. The analysis of variance for components of bunch production and oil yield showed highly significant (p?<?0.001) statistical differences between geographical regions and among families for all traits evaluated. The SSRs were highly informative, suggesting high genetic diversity (H _T ?=?0.666) among the accessions evaluated. However, the clustering pattern at both morpho-agronomic and molecular levels did not match the geographical distribution of accessions, showing a low genetic differentiation (G _ST ?=?0.039) between regions. On the other hand, genotypic (G _ST ?=?0.150) and phenotypic differences were found among families, which could offer the potential for future genetic gains in the oil palm. The information generated indicates that the evaluated accessions have desirable characteristics that should be included in breeding programs, which could expand the genetic basis of the crop.