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We examined the effects of interferon-alpha (IFN-alpha) treatment on the growth, cell cycle, proliferation, and apoptotic parameters as well as adhesive properties and proteome of chronic myelogenous leukemia (CML)-derived K562 cells. IFN-alpha treatment (200 to 600 U/ml, 24 to 72 h) suppressed growth and caused accumulation of K562 cells in the S-phase of cell cycle (increase in S-phase cells by up to 52% in comparison with the untreated controls) at the expenses of cells in G1-phase. No transition of cells to G0-phase occurred as followed from Ki-67 protein determination. Although the level of chimeric gene product, BCR-ABL mRNA coding for BCR-ABL protein with anti-apoptotic properties, decreased by 30%, apoptosis was not triggered as judged from Annexin-V, APO2.7, and TUNEL assays. Adhesion of K562 cells to fibronectin-coated surfaces increased by up to 52% as determined by calcein assay. The proteomic analysis (2-D electrophoresis in combination with mass spectrometry, MALDI-MS) revealed a single protein, ubiquitine cross-reactive protein (UBCR), whose level markedly increased due to IFN-alpha treatment. The ubiquitination-like directed degradation processes may thus play a role in the mechanism of IFN-alpha antiproliferative effects.

Background Comparison between consensual approaches for the detection of paroxysmal nocturnal hemoglobinuria (PNH) clones by flow cytometry (FCM) following the international clinical cytometry society (ICCS) guidelines has not been widely reported. Methods We determined the performance characteristics of 4, 5, and 6-color protocols for white blood cell (WBC) and one and two-color protocols for red blood cell (RBC) evaluation for different PNH target clones and compared results from PNH patient analysis. Results Coefficient of variation (CV) for precision/reproducibility analysis ranged from 0.01%/0.12% to 2.56%/ 3.59% for granulocytes, from 0.07%/0.08% to 3.87%/11.61% for monocytes and from 0.4%/1.02% to 6.53%/ 5.1% for RBCs within different approaches and target PNH clones. Comparison of individual protocols revealed excellent correlation (r = 0.99), Wilcoxon rank tests found no statistically significant differences (p > 0.05), Bland-Altman analysis proved agreement for all PNH clones (mean bias ranging from 0.02 to 2.2). Conclusions Our results confirm good intralaboratory characteristics for precision and reproducibility analysis, excellent correlation and agreement between approaches underlining the primary role of optimally selected glycophosphatidylinositol (GPI)-specific reagents and secondary role of number, type of gating reagents and gating strategy.

Histone deacetylase inhibitors (HDACi) are emerging new class of anticancer agents that act by inhibiting cell growth, inducing cell cycle arrest and apoptosis of various cancer cells. However, in some conditions, apoptosis can be blocked and non apoptotic cell death and irreversible growth arrest, namely senescence, can be activated as potential tumor-suppressor mechanism. Here we evaluated the dosage effects of HDAC inhibitors suberoylanilide hydroxamic acid (SAHA) and valproic acid (VPA) in a series of human leukaemia cell lines. We investigated, what concentration of SAHA and VPA can optimally induce apoptosis, growth inhibition or stress-induced premature senescence. We have found that SAHA inhibited proliferation and induced apoptosis in concentration 1000x lower than VPA. The senescence phenotype was preferentially induced by lower dosage of HDACi and required longer incubation time (5 days) while apoptosis was induced by higher dosage and appeared already after 24h. The optimal doses for the induction of cell death are 2,5-5 μM of SAHA and 2,5-5 mM of VPA. These doses of HDACi induce both apoptosis and senescence of studied leukemia cell lines.

Diabetes mellitus is associated with a number of prothrombotic abnormalities, and correction of these abnormalities might translate into the reduction of cardiovascular risk. Glitazones improve endothelial function and reduce inflammation, but much less is known about their effect on thrombogenic factors. We have therefore studied the effect of rosiglitazone on leukocyte and soluble thrombogenic markers in patients with type 2 diabetes mellitus. Thirty-three subjects with type 2 diabetes and 32 normal controls were included; patients were examined at baseline and after 5 months of rosiglitazone treatment (4 mg/day). We measured leukocyte-platelet aggregates and leukocyte expression of either P-selectin glycoprotein ligand 1 (PSGL-1) or receptor for urokinase-type plasminogen activator (uPAR) using flow cytometry, as well as several circulating soluble thrombogenic markers by ELISA method. Leukocyte expression of uPAR and PSGL-1 was significantly higher in patients than in controls. Leukocyte-platelet aggregates and leukocyte expression of uPAR and PSGL-1 significantly decreased after rosiglitazone. There was also significant decrease in CRP and fibrinogen levels, but there was no effect of diabetes and/or rosiglitazone on other circulating molecules. In conclusions, we observed a substantial improvement in the expression of thrombogenic markers on leukocytes after rosiglitazone treatment, suggesting the novel antithrombotic effects of rosiglitazone.

Diabetes mellitus is associated with increased inflammatory response, which may contribute to atherosclerosis progression. Experimental results demonstrated anti-inflammatory activity of glitazones; their effect on leukocyte adhesion molecules has not been studied to date. We therefore studied the effect of rosiglitazone treatment on leukocyte surface expression of adhesion molecules in patients with type 2 diabetes mellitus and compared our results with findings in healthy subjects. 33 subjects with type 2 diabetes and 32 healthy controls were included; patients were examined at baseline and after 5 months of rosiglitazone treatment (4 mg/d). Leukocyte expression of adhesion molecules LFA-1, CD18 and ICAM-1 was quantified using flow cytometry; in addition, CD14 (lipopolysaccharide receptor) expression was analyzed as a marker of nonspecific immunity. The expression of examined molecules at baseline was higher in patients compared to controls. Despite only mild decrease in blood glucose, rosiglitazone treatment induced substantial decrease of CD18 and CD14 expression and borderline decrease of LFA-1 and ICAM-1 expression (on monocytes only). We thus observed improvement in the expression of leukocyte inflammatory markers after rosiglitazone treatment. This effect is supposed to be mediated by direct effect of rosiglitazone on PPAR-γ receptors on leukocytes.

Atherogenesis involves the migration of leukocytes into vascular subendothelial space, a process mediated by endothelial and leukocyte cell adhesion molecules. Endothelial molecules are assessed indirectly via serum levels, but leukocyte molecules can be assessed directly. We have therefore hypothesized that leukocyte adhesion molecules are altered to a greater degree in hypercholesterolemia than serum endothelial adhesion molecules. We examined 29 subjects with hypercholesterolemia and 27 controls at baseline and after 12 weeks of atorvastatin treatment (20 mg/day). Expression of leukocyte integrins CD11a, CD11b, CD18, and CD49d and of L-selectin was measured by flow cytometry. Serum ICAM-1, E-selectin and von Willebrand factor were measured by ELISA. Expression of leukocyte adhesion molecules was significantly higher in patients at baseline than in the controls, except for CD11a. Expression significantly decreased after atorvastatin in most adhesion molecules except for CD11b. In contrast, there was no effect of hypercholesterolemia and/or atorvastatin on the serum endothelial molecules. Leukocyte but not endothelial adhesion molecules were influenced by hypercholesterolemia and by lipid lowering treatment. Leukocyte molecules may therefore be a more sensitive marker of atherogenesis than endothelial molecules. Our results support the role of increased leukocyte adhesiveness in atherogenesis.

Bone marrow transplantation or ponatinib treatment are currently recommended strategies for management of patients with chronic myeloid leukemia (CML) harboring the T315I mutation and compound or polyclonal mutations. However, in some individual cases, these treatment scenarios cannot be applied. We used an alternative treatment strategy with interferon-α (IFN-α) given solo, sequentially or together with TKI in a group of 6 cases of high risk CML patients, assuming that the TKI-independent mechanism of action may lead to mutant clone repression. IFN-α based individualized therapy decreases of T315I or compound mutations to undetectable levels as assessed by next-generation deep sequencing, which was associated with a molecular response in 4/6 patients. Based on the observed results from immune profiling, we assumed that the principal mechanism leading to the success of the treatment was the immune activation induced with dasatinib pre-treatment followed by restoration of immunological surveillance after application of IFN-α therapy. Moreover, we showed that sensitive measurement of mutated BCR-ABL1 transcript levels augments the safety of this individualized treatment strategy.