α-Tocopherol at Nanomolar Concentration Protects Cortical Neurons against Oxidative Stress.

The aim of the present work is to study the mechanism of the α-tocopherol (α-T) protective action at nanomolar and micromolar concentrations against H2O2-induced brain cortical neuron death. The mechanism of α-T action on neurons at its nanomolar concentrations characteristic for brain extracellular space has not been practically studied yet. Preincubation with nanomolar and micromolar α-T for 18 h was found to increase the viability of cortical neurons exposed to H2O2; α-T effect was concentration-dependent in the nanomolar range. However, preincubation with nanomolar α-T for 30 min was not effective. Nanomolar and micromolar α-T decreased the reactive oxygen species accumulation induced in cortical neurons by the prooxidant. Using immunoblotting it was shown that preincubation with α-T at nanomolar and micromolar concentrations for 18 h prevented Akt inactivation and decreased PKCδ activation induced in cortical neurons by H2O2. α-T prevented the ERK1/2 sustained activation during 24 h caused by H2O2. α-T at nanomolar and micromolar concentrations prevented a great increase of the proapoptotic to antiapoptotic proteins (Bax/Bcl-2) ratio, elicited by neuron exposure to H2O2. The similar neuron protection mechanism by nanomolar and micromolar α-T suggests that a "more is better" approach to patients' supplementation with vitamin E or α-T is not reasonable.

GM1 and GD1a gangliosides modulate toxic and inflammatory effects of E. coli lipopolysaccharide by preventing TLR4 translocation into lipid rafts.

Exogenous gangliosides are known to inhibit the effects of Escherichia coli lipopolysaccharide (LPS) in different cells exhibiting anti-inflammatory and immunosuppressive activities. The mechanisms underlying ganglioside action are not fully understood. Because LPS recognition and receptor complex formation occur in lipid rafts, and gangliosides play a key role in their maintenance, we hypothesize that protective effects of exogenous gangliosides would depend on inhibition of LPS signaling via prevention of TLR4 translocation into lipid rafts. The effect of GM1 and GD1a gangliosides on LPS-induced toxic and inflammatory reactions in PC12 cells, and in epithelial cells isolated from the frog urinary bladder, was studied. In PC12 cells, GD1a and GM1 significantly reduced the effect of LPS on the decrease of cell survival and on stimulation of reactive oxygen species production. In epithelial cells, gangliosides decreased LPS-stimulated iNOS expression, NO, and PGE2 production. Subcellular fractionation, in combination with immunoblotting, showed that pretreatment of cells with GM1, GD1a, or methyl-ß-cyclodextrin, completely eliminated the effect of LPS on translocation of TLR4 into lipid rafts. The results are consistent with the hypothesis that ganglioside-induced prevention of TLR4 translocation into lipid rafts could be a mechanism of protection against LPS in various cells.

GM1 ganglioside activates ERK1/2 and Akt downstream of Trk tyrosine kinase and protects PC12 cells against hydrogen peroxide toxicity.

Ganglioside GM1 at micro- and nanomolar concentrations was shown to increase the viability of pheochromocytoma PC12 cells exposed to hydrogen peroxide and diminish the accumulation of reactive oxygen species and oxidative inactivation of Na(+),K(+)-ATPase, the effects of micromolar GM1 being more pronounced than those of nanomolar GM1. These effects of GM1 were abolished by Trk receptor tyrosine kinase inhibitor and diminished by MEK1/2, phosphoinositide 3-kinase and protein kinase C inhibitors. Hydrogen peroxide activates Trk tyrosine kinase; Akt and ERK1/2 are activated downstream of this protein kinase. GM1 was found to activate Trk receptor tyrosine kinase in PC12 cells. GM1 (100 nM and 10 µM) increased the basal activity of Akt, but did not change Akt activity in cells exposed to hydrogen peroxide. Basal ERK1/2 activity in PC12 cells was increased by GM1 at a concentration of 10 µM, but not at nanomolar concentrations. Activation of ERK1/2 by hydrogen peroxide was enhanced by GM1 at a concentration of 10 µM and to a lesser extent at a concentration of 100 nM. Thus, the protective and metabolic effects of GM1 ganglioside on PC12 cells exposed to hydrogen peroxide appear to depend on the activation of Trk receptor tyrosine kinase and downstream activation of Akt and ERK1/2.

Computational analysis of R-X oxidative addition to Pd nanoparticles.

Oxidative addition (OA) is a necessary step in mechanisms of widely used synthetic methodologies such as the Heck reaction, cross-coupling reactions, and the Buchwald-Hartwig amination. This study pioneers the exploration of OA of aryl halide to palladium nanoparticles (NPs), a process previously unaddressed in contrast to the activity of well-studied Pd(0) complexes. Employing DFT modeling and semi-empirical metadynamics simulations, the oxidative addition of phenyl bromide to Pd nanoparticles was investigated in detail. Energy profiles of oxidative addition to Pd NPs were analyzed and compared to those involving Pd(0) complexes forming under both ligand-stabilized (phosphines) and ligandless (amine base) conditions. Metadynamics simulations highlighted the edges of the (1 1 1) facets of Pd NPs as the key element of oxidative addition activity. We demonstrate that OA to Pd NPs is not only kinetically facile at ambient temperatures but also thermodynamically favorable. This finding accentuates the necessity of incorporating OA to Pd NPs in future investigations, thus providing a more realistic view of the involved catalytic mechanisms. These results enhance the understanding of aryl halide (cross-)coupling reactions, reinforcing the concept of a catalytic "cocktail". This concept posits dynamic interconversions between diverse active and inactive centers, collectively affecting the outcome of the reaction. High activity of Pd NPs in direct C-X activation paves the way for novel approaches in catalysis, potentially enhancing the field and offering new catalytic pathways to consider.

First-line steroid-free systemic treatment of acute and chronic graft-versus-host disease after novel prophylaxis regimens.

In the early randomized trials the efficacy of calcineurin inhibitors (CNI) in the treatment of graft-versus-host disease (GVHD) was comparable to corticosteroids (CS), but these results became obsolete with the introduction of CNIs in prophylaxis. Recently several effective CNI-free GVHD prophylaxis regimens were introduced based on posttransplantation cyclophosphamide (PTCY) and αß ex vivo T-cell depletion (αß-TCD). Among patients treated under these protocols 34 patients with grade II-IV acute (aGVHD) and 40 with moderate and severe chronic (cGVHD) disease were treated with CNIs or other CS-free regimens as the first line. Overall response rate (ORR) was significantly higher in cGVHD than in aGVHD: 80% (95% CI 68-92) vs 47% (95% CI 30-64%), p = 0.0031. In aGVHD it was almost completely restricted to isolated stage III skin GVHD. In cGVHD patients with moderate disease ORR was higher than in severe: 96% (95% CI 88-100%) vs 56% (95%CI 32-81%), p = 0.0022. Two-year overall survival was 76% (95% CI 58-87%) in aGVHD and 95% (95% CI 81-99%) in cGVHD. Failure-free survival was 21% (95% CI 9-37%) in aGVHD and 81% (95% CI 64-91%) in cGVHD. Patients responding to steroid-free regimens had lower use of systemic antibiotics (p = 0.0095), antifungals (p = 0.0319) and antivirals (p < 0.0001).

20-Hydroxyecdysone Confers Antioxidant and Antineoplastic Properties in Human Non-Small Cell Lung Cancer Cells.

20-Hydroxyecdysone (20E) is an arthropod hormone which is synthesized by some plants as part of their defense mechanism. In humans, 20E has no hormonal activity but possesses a number of beneficial pharmacological properties including anabolic, adaptogenic, hypoglycemic, and antioxidant properties, as well as cardio-, hepato-, and neuroprotective features. Recent studies have shown that 20E may also possess antineoplastic activity. In the present study, we reveal the anticancer properties of 20E in Non-Small Cell Lung Cancer (NSCLC) cell lines. 20E displayed significant antioxidant capacities and induced the expression of antioxidative stress response genes. The RNA-seq analysis of 20E-treated lung cancer cells revealed the attenuation of genes involved in different metabolic processes. Indeed, 20E suppressed several enzymes of glycolysis and one-carbon metabolism, as well as their key transcriptional regulators-c-Myc and ATF4, respectively. Accordingly, using the SeaHorse energy profiling approach, we observed the inhibition of glycolysis and respiration mediated by 20E treatment. Furthermore, 20E sensibilized lung cancer cells to metabolic inhibitors and markedly suppressed the expression of Cancer Stem Cells (CSCs) markers. Thus, in addition to the known beneficial pharmacological activities of 20E, our data uncovered novel antineoplastic properties of 20E in NSCLC cells.

Long-term outcomes of third-line therapy with tyrosine kinase inhibitors in chronic phase chronic myeloid leukemia: A real-life experience.

Introduction: Tyrosine kinase inhibitor (TKI) therapy has greatly improved the prognosis of patients with chronic myeloid leukemia (CML), improving the survival expectancy of patients with chronic phase (CP) CML to that of the general population. However, despite these advances, nearly 50% of patients with CP CML experience failure to respond to frontline therapy, and most fail to respond to the subsequent second-line TKI. Treatment guidelines for patients failing second-line therapy are lacking. This study aimed to determine the efficacy of TKIs as third-line therapy in a "real-world" clinical practice setting and identify factors favorably influencing the long-term outcomes of therapy. Methods: We have retrospectively analyzed the medical records of 100 patients with CP CML. Results: The median age of the patients was 51 (range, 21-88) years, and 36% of the patients were men. The median duration of the third-line TKI therapy was 22 (range, 1- 147) months. Overall, the rate of achieving complete cytogenetic response (CCyR) was 35%. Among the four patient groups with different levels of responses at baseline, the best results were achieved in the groups with any CyR at the baseline of third-line therapy. Thus, СCyR was reached in all 15 and 8/ 16 (50%) patients with partial cytogenetic response (PCyR) or minimal or minor CyR (mmCyR), respectively, whereas CCyR was detected only in 12/69 (17%) patients without any CyR at baseline (p < 0.001). Univariate regression analysis revealed that the factors negatively associated with CCyR achievement in thirdline TKI therapy were the absence of any CyR on first- or second-line TKI therapy (p < 0.001), absence of CHR prior to third-line TKI (p = 0.003), and absence of any CyR prior to third-line TKI (p < 0.001). During the median observation time from treatment initiation to the last visit [56 (4-180) months], 27% of cases progressed into accelerated phase or blast phase CML, and 32% of patients died. Discussion: Progression-free survival (PFS) and overall survival (OS) were significantly higher in patients with CCyR on third-line than in the group without CCyR on third-line therapy. At the last visit, third-line TKI therapy was ongoing in 18% of patients, with a median time of treatment exposure of 58 (range, 6-140) months; 83% of these patients had stable and durable CCyR, suggesting that patients without CHR at baseline and without CCyR at least by 12 months on third-line TKI should be candidates for allogeneic stem cell transplantation, third-generation TKIs, or experimental therapies.

Trends in Outcome of Hematopoietic Stem Cell Transplantation: 5000 Transplantations and 30 Years of Single-Center Experience.

In this single-center analysis, we evaluated the trends in 5185 hematopoietic cell transplantations performed between 1990 and 2022. The study group comprised 3237 allogeneic (alloHCT) and 1948 autologous (autoHCT) hematopoietic cell transplantations. In the multivariate analysis, there was an improvement in event-free-survival (EFS) after autoHCT (HR 0.6, 95% CI 0.4-0.7, p < 0.0001) due to reduced cumulative incidence of relapse in the last five years (56% in 2010-2014 vs. 38% in 2015-2022). An improvement in EFS after alloHCT over time was observed (HR 0.33, 95% CI 0.23-0.48, p < 0.0001), which was due to reduced non-relapse mortality. No difference in cumulative relapse incidence was observed over the last decade for allografted patients. Survival after autoHCT improved in Hodgkin's disease (HR 0.1, 95% CI 0.1-0.3), multiple myeloma (HR 0.4, 95% CI 0.2-0.7) and solid tumors (HR 0.2, 95% CI 0.2-0.4), while after alloHCT, improvement was observed in acute myeloid leukemia (HR 0.3, 95% CI 0.1-0.5), acute lymphoblastic leukemia (HR 0.2, 95% CI 0.1-0.5), Hodgkin's disease (HR 0.1, 95% CI 0.0-0.4), non-Hodgkin's lymphomas and chronic lymphocytic leukemia (HR 0.2, 95% CI 0.0-0.6), inborn diseases (HR 0.2, 95% CI 0.2-0.4) and acquired aplastic anemia with matched related donors and matched unrelated donors (HR 0.3, 95% CI 0.2-0.8).

α-Tocopherol at nanomolar concentration protects PC12 cells from hydrogen peroxide-induced death and modulates protein kinase activities.

The aim of this work was to compare protective and anti-apoptotic effects of α-tocopherol at nanomolar and micromolar concentrations against 0.2 mM H(2)O(2)-induced toxicity in the PC12 neuronal cell line and to reveal protein kinases that contribute to α-tocopherol protective action. The protection by 100 nM α-tocopherol against H(2)O(2)-induced PC12 cell death was pronounced if the time of pre-incubation with α-tocopherol was 3-18 h. For the first time, the protective effect of α-tocopherol was shown to depend on its concentration in the nanomolar range (1 nM < 10 nM < 100 nM), if the pre-incubation time was 18 h. Nanomolar and micromolar α-tocopherol decreased the number of PC12 cells in late apoptosis induced by H(2)O(2) to the same extent if pre-incubation time was 18 h. Immunoblotting data showed that α-tocopherol markedly diminished the time of maximal activation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and protein kinase B (Akt)-induced in PC12 cells by H(2)O(2). Inhibitors of MEK 1/2, PI 3-kinase and protein kinase C (PKC) diminished the protective effect of α-tocopherol against H(2)O(2)-initiated toxicity if the pre-incubation time was long. The modulation of ERK 1/2, Akt and PKC activities appears to participate in the protection by α-tocopherol against H(2)O(2)-induced death of PC12 cells. The data obtained suggest that inhibition by α-tocopherol in late stage ERK 1/2 and Akt activation induced by H(2)O(2) in PC12 cells makes contribution to its protective effect, while total inhibition of these enzymes is not protective.

Graft-versus-Host Disease Prophylaxis with Post-Transplantation Bendamustine in Patients with Refractory Acute Leukemia: A Dose-Ranging Study.

The prognosis of acute leukemia refractory to induction chemotherapy or immunotherapy is dismal. Salvage allogeneic hematopoietic stem cell transplantation (HSCT) is widely used option for these patients, but only 10% to 15% of patients are cured by the procedure. Preclinical studies indicate that substitution of post-transplantation cyclophosphamide with bendamustine (PTB) in a prophylaxis regimen may be associated with an augmented graft-versus-leukemia (GVL) reaction. The aim of this study was to establish the optimal dose of PTB and evaluate the antileukemic effect of HSCT with this type of graft-versus-host disease (GVHD) prophylaxis. In the prospective trial (NCT02799147), PTB was administered in doses of 140, 100, and 70 mg/m2 on days +3 and +4. Myeloablative conditioning with fludarabine and oral busulfan was provided to all patients. The first 12 patients received single-agent PTB, and subsequent patients received combination therapy with tacrolimus and mycophenolate mofetil (MMF). Inclusion criteria were acute myelogenous leukemia (AML) or acute lymphoblastic leukemia (ALL) refractory to at least one induction course of chemotherapy or target therapy and ≥5% clonal blasts in the bone marrow. The study cohort comprised 22 patients with AML and 5 with ALL. Seven patients were enrolled in the 140 mg/m2 group (due to a stopping rule), and 10 each were enrolled in the 100 mg/m2 and 70 mg/m2 groups. Primary refractory disease was documented in 41% of the patients, and secondary refractory was documented in 59%. The median blast count in the bone marrow at the start of the conditioning was 18% (range, 6% to 97%). Transplantation was performed with a matched sibling donor in 5 patients, a matched or mismatched unrelated donor in 15, and a haploidentical donor in 7. Engraftment was documented in 93% of the patients, including 89% with complete remission and 63% without measurable residual disease. After PTB prophylaxis, we observed an unusual complication, a cytokine release syndrome (CRS), in 70% of the patients, including grade 3 to 5 CRS in 44%. The most frequent clinical symptoms included high fever in 67% of patients, abnormal liver function tests in 67%, pancreatitis in 63%, skin vasculitis in 56%, enterocolitis in 48%, inflammation of oral mucosa in 37%, disseminated intravascular coagulation in 37%, and central nervous system toxicity in 26%. The development of CRS was associated with use of an HLA-mismatched donor (75% versus 20%; P = .0043). Classic acute GVHD was documented in 44% of the patients. Grade II-IV acute GVHD was associated with grade 3 to 5 CRS (67% versus 25%; P = .031). Moderate and severe chronic GVHD in the 100-day survivors were more often observed after single-agent PTB than after the combination immunosuppression (100% versus 18%; P = .002). A relatively low relapse rate was observed for this patient population. Three-year overall survival was 28% (95% confidence interval [CI], 13% to 46%), and event-free survival was 29% (95% CI, 13% to 46%). Nonrelapse mortality was 46% (95% CI, 25% to 64%), and the cumulative incidence of relapse was 26% (95% CI, 11% to 44%). No relapses were documented after day +100. There were no statistically significant differences among the dose groups (P = .3481); however, survival was higher in the 100 mg/kg group. Survival was higher in patients with AML compared with those with ALL (35% versus 0%; P = .0157). PTB represents a promising option to augment the GVL effect in refractory AML; however, the high CRS-associated mortality necessitates additional studies to reduce the risk of this complication. Thus, routine clinical application of PTB cannot be currently recommended. Combination immunosuppression with tacrolimus and MMF partially ameliorates these complications, at least in the setting of HLA-matched allografts. Biological mechanisms of CRS and GVL after PTB require further elucidation.

Protective and antioxidative effects of GM1 ganglioside in PC12 cells exposed to hydrogen peroxide are mediated by Trk tyrosine kinase.

GM1 ganglioside was found to increase the survival of PC12 cells exposed to H(2)O(2), its action was blocked by Trk tyrosine kinase inhibitor K-252a. Thus, the inhibition of H(2)O(2) cytotoxic action by GM1 constituted 52.8 +/- 4.3%, but in the presence of 1.0 microM K-252a it was only 11.7 +/- 10.8%, i.e. the effect of GM1 became insignificant. Exposure to GM1 markedly reduced the increased accumulation of reactive oxygen species (ROS) and diminished the inactivation of Na(+),K(+)-ATPase induced in PC12 cells by H(2)O(2), but in the presence of K-252a GM1 did not change these metabolic parameters. The inhibitors of extracellular signal-regulated protein kinase, phosphatidyl inositol 3-kinase and protein kinase C decreased the effects of GM1. A combination of these protein kinase inhibitors reduced inhibition of H(2)O(2) cytotoxic action by GM1 to the larger extent than each of the inhibitors and practically abolished the ability of GM1 to decrease H(2)O(2)-induced ROS accumulation. The protective and antioxidative effects of GM1 in PC12 cells exposed to H(2)O(2) appear to be mediated by activation of Trk receptor tyrosine kinase and the protein kinases downstream from this enzyme.