In Chronic Lymphocytic Leukemia the JAK2/STAT3 Pathway Is Constitutively Activated and Its Inhibition Leads to CLL Cell Death Unaffected by the Protective Bone Marrow Microenvironment

The bone marrow microenvironment promotes proliferation and drug resistance in chronic lymphocytic leukemia (CLL). Although ibrutinib is active in CLL, it is rarely able to clear leukemic cells protected by bone marrow mesenchymal stromal cells (BMSCs) within the marrow niche. We investigated the modulation of JAK2/STAT3 pathway in CLL by BMSCs and its targeting with AG490 (JAK2 inhibitor) or Stattic (STAT3 inhibitor). B cells collected from controls and CLL patients, were treated with medium alone, ibrutinib, JAK/Signal Transducer and Activator of Transcription (STAT) inhibitors, or both drugs, in the presence of absence of BMSCs. JAK2/STAT3 axis was evaluated by western blotting, flow cytometry, and confocal microscopy. We demonstrated that STAT3 was phosphorylated in Tyr705 in the majority of CLL patients at basal condition, and increased following co-cultures with BMSCs or IL-6. Treatment with AG490, but not Stattic, caused STAT3 and Lyn dephosphorylation, through re-activation of SHP-1, and triggered CLL apoptosis even when leukemic cells were cultured on BMSC layers. Moreover, while BMSCs hamper ibrutinib activity, the combination of ibrutinib+JAK/STAT inhibitors increase ibrutinib-mediated leukemic cell death, bypassing the pro-survival stimuli derived from BMSCs. We herein provide evidence that JAK2/STAT3 signaling might play a key role in the regulation of CLL-BMSC interactions and its inhibition enhances ibrutinib, counteracting the bone marrow niche

Targeted activation of the SHP-1/PP2A signaling axis elicits apoptosis of chronic lymphocytic leukemia cells

Lyn, a member of the Src family of kinases, is a key factor in the dys-regulation of survival and apoptotic pathways of malignant B cells in chronic lymphocytic leukemia. One of the effects of Lyn's action is spatial and functional segregation of the tyrosine phosphatase SHP-1 into two pools, one beneath the plasma membrane in an active state promoting pro-survival signals, the other in the cytosol in an inhibited conformation and unable to counter the elevated level of cytosolic tyrosine phosphorylation. We herein show that SHP-1 activity can be elicited directly by nintedanib, an agent also known as a triple angiokinase inhibitor, circumventing the phospho-S591-dependent inhibition of the phosphatase, leading to the dephosphorylation of pro-apoptotic players such as procaspase-8 and serine/threonine phosphatase 2A, eventually triggering apoptosis. Furthermore, the activation of PP2A by using MP07-66, a novel FTY720 analog, stimulated SHP-1 activity via dephosphorylation of phospho-S591, which unveiled the existence of a positive feedback signaling loop involving the two phosphatases. In addition to providing further insights into the molecular basis of this disease, our findings indicate that the PP2A/SHP-1 axis may emerge as an attractive, novel target for the development of alternative strategies in the treatment of chronic lymphocytic leukemia

Lyn sustains oncogenic signaling in chronic lymphocytic leukemia by strengthening SET-mediated inhibition of PP2A.

Aberrant protein kinase activities, and the consequent dramatic increase of Ser/Thr and -Tyr phosphorylation, promote the deregulation of the survival pathways in chronic lymphocytic leukemia (CLL), which is crucial to the pathogenesis and progression of the disease. In this study, we show that the tumor suppressor Protein Phosphatase 2A (PP2A), one of the major Ser/Thr phosphatase, is in an inhibited form due to the synergistic contribution of two events, the interaction with its physiological inhibitor SET and the phosphorylation of Y307 of the catalytic subunit of PP2A. The latter event is mediated by Lyn, a Src family kinase previously found to be overexpressed, delocalized and constitutively active in CLL cells. This Lyn/PP2A axis accounts for the persistent high level of phosphorylation of the phosphatase's targets and represents a key connection linking phosphotyrosine- and phosphoserine/threonine-mediated oncogenic signals. The data herein presented show that the disruption of the SET/PP2A complex by a novel FTY720-analogue (MP07-66) devoid of immunosuppressive effects leads to the reactivation of PP2A, which in turn triggers apoptosis of CLL cells. When used in combination with SFK inhibitors, the action of MP07-66 is synergistically amplified, providing a new option in the therapeutic strategy for CLL patients

HS1, a Lyn Kinase Substrate, Is Abnormally Expressed in B-Chronic Lymphocytic Leukemia and Correlates with Response to Fludarabine-Based Regimen

In B-Chronic Lymphocytic Leukemia (B-CLL) kinase Lyn is overexpressed, active, abnormally distributed, and part of a cytosolic complex involving hematopoietic lineage cell-specific protein 1 (HS1). These aberrant properties of Lyn could partially explain leukemic cells’ defective apoptosis, directly or through its substrates, for example, HS1 that has been associated to apoptosis in different cell types. To verify the hypothesis of HS1 involvement in Lyn-mediated leukemic cell survival, we investigated HS1 protein in 71 untreated B-CLL patients and 26 healthy controls. We found HS1 overexpressed in leukemic as compared to normal B lymphocytes (1.38±0.54 vs 0.86±0.29, p<0.01), and when HS1 levels were correlated to clinical parameters we found a higher expression of HS1 in poor-prognosis patients. Moreover, HS1 levels significantly decreased in ex vivo leukemic cells of patients responding to a fludarabine-containing regimen. We also observed that HS1 is partially localized in the nucleus of neoplastic B cells. All these data add new information on HS1 study, hypothesizing a pivotal role of HS1 in Lyn-mediated modulation of leukemic cells’ survival and focusing, one more time, the attention on the BCR-Lyn axis as a putative target for new therapeutic strategies in this disorder

Furostanol saponins in Allium cepa L. var. tropeana seeds.

An analysis of the polar extracts from seeds of Allium caepa L. var. tropeana led to the isolation of eight furostanol saponins, one of which was previously reported in the literature. On the basis of 1D, 2D NMR and mass spectrometry data, the structures of the compounds were elucidated as 1-O-β-D-glucopyranosyl-(25R)-furost-5(6)-en-1β,3β,22α,26-tetraol-26-O-α-L-rhamnopyranosyl-(1‴ → 2″)-O-α-L-arabinopyranoside (1a), its epimer at position 22, 1-O-β-D-glucopyranosyl-(25R)-furost-5(6)-en-1β,3β,22β,26-tetraol-26-O-α-L-rhamnopyranosyl-(1‴ → 2″)-O-α-L-arabinopyranoside (1b), 1-O-β-D-glucopyranosyl-22-O-methyl-(25R)-furost-5(6)-en-1β,3β,22ξ,26-tetraol-26-O-α-L-rhamnopyranosyl-(1‴ → 2″)-O-α-L-arabinopyranoside (probably artefact) (2), 1-O-β-D-glucopyranosyl-(25R)-furost-5(6)-en-1β,3β,22β,26-tetraol-26-O-α-L-rhamnopyranosyl-(1‴ → 6″)-O-β-D-galactopyranoside (3), 1-O-β-D-glucopyranosyl-22-O-methyl-(25R)-furost-5(6)-en-1β,3β,22ξ,26-tetraol-26-O-α-L-rhamnopyranosyl-(1‴ → 6″)-O-β-D-galactopyranoside (probably artefact) (4), 26-O-β-D-glucopyranosyl-(25R)-furost-5(6)-en-3β,22α,26-triol-3-O-α-L-rhamnopyranosyl-(1″ → 2′)-O-[β-D-glucopyranosyl-(1‴ → 6′)-O]-β-D-glucopyranoside (5a) and its epimer at position 22,26-O-β-D-glucopyranosyl-(25R)-furost-5(6)-en-3β,22β,26-triol-3-O-α-L-rhamnopyranosyl-(1″ → 2′)-O-[β-D-glucopyranosyl-(1‴ → 6′)-O]-β-D-glucopyranoside (5b) and the known compound 26-O-β-D-glucopyranosyl-22-O-methyl-(25R)-furost-5(6)-en-3β,22ξ,26-triol-3-O-α-L-rhamnopyranosyl-(1″ → 2′)-O-[β-D-glucopyranosyl-(1‴ → 6′)-O]-β-D-glucopyranoside (6) [Mimaki, Y., Satou, T., Kuroda, M., Sashida, Y., & Hatakeyama, Y. (1999). Steroidal saponins from the bulbs of Lilium candidum. Phytochemistry, 51, 567–573]. This is the first report on furostanol saponins in the seeds of Allium caepa L. var. tropeana

Development of new atherosclerotic plaque in hypertensive patients: an observational registry study from the Campania-Salute network

Carotid atherosclerotic plaques (CAPs) can develop despite appropriate antihypertensive therapy. In this observational study, we assessed characteristics associated with risk of incident CAP in a large hypertensive registry

Rac 1 modulates endothelial function and platelet aggregation in diabetes mellitus

Background--Vascular complications and abnormal platelet function contribute to morbidity and mortality in diabetes mellitus. We hypothesized that the Rho-related GTPase protein, Rac1, can influence both endothelial and platelet function and might represent a potential novel therapeutic target in diabetes mellitus. Methods and Results--We used both in vitro and ex vivo approaches to test the effects of pharmacological inhibition of Rac1 during hyperglycemic condition. We evaluated the effect of NSC23766, a pharmacological inhibitor of Rac1, on vascular function in diabetic mice and platelet aggregation in diabetic subjects. We demonstrated that the administration of NSC23766 protects from hyperglycemia-induced endothelial dysfunction, restoring NO levels, and reduces oxidative stress generated by nicotinamide adenine dinucleotide phosphate oxidase. Mechanistically, we identified Rho-associated coiled-coil serine/threonine kinase-1 as a downstream target of Rac1. Moreover, we reported that during hyperglycemic conditions, human platelets showed hyperactivation of Rac1 and impaired NO release, which were both partially restored after NSC23766 treatment. Finally, we characterized the antiplatelet effect of NSC23766 during hyperglycemic conditions, demonstrating the additional role of Rac1 inhibition in reducing platelet aggregation in diabetic patients treated with common antiplatelet drugs. Conclusions--Our data suggest that the pharmacological inhibition of Rac1 could represent a novel therapeutic strategy to reduce endothelial dysfunction and platelet hyperaggregation in diabetes mellitus

Prediction of Long-Term Survival in Chronic Heart Failure by Multiple Biomarker Assessment: A 15-Year Prospective Follow-Up Study

Background: In chronic heart failure (CHF), several plasma biomarkers identify subjects at risk of death over the midterm. However, their long-term predictive value in the context of other candidate predictors has never been assessed. This information may prove valuable in the management of a chronic disease with a long natural history, as CHF is today. Hypothesis: We aimed to assess the very-long-term prognostic power of a set of biomarkers to identify CHF patients at highest risk for all-cause mortality. Methods: A group of 106 consecutive outpatients with CHF (85 male and 21 female, median age 56 y) was followed for 15 years. Echocardiographic tracings and blood samples were collected at study entry to evaluate cardiac function, plasma atrial natriuretic peptide (ANP), aldosterone, and erythropoietin, and plasma renin activity. The relationships between biomarkers, clinical and echocardiographic variables, and mortality were assessed. Results: After 15 years, 86 of the 106 patients (81%) had died. Multivariate analysis showed that ANP was the best independent predictor of survival over several clinical, echocardiographic, and humoral variables (hazard ratio: 5.62, 95% confidence interval: 3.37-9.39, P < 0.001 for plasma levels < median value of 71 pg/mL). Plasma renin activity and erythropoietin provided prognostic information in univariate analysis, but lost their predictive power when adjusted for covariates. Conclusions: The present study represents the longest available follow-up of patients with CHF evaluating the prognostic power of multiple biomarkers. It shows that a simple assessment of plasma ANP levels is the strongest long-term predictor of death in all stages of heart failure

Advanced imaging tools for evaluating cardiac morphological and functional impairment in hypertensive disease

Arterial hypertension represents a systemic burden, and it is responsible of various morphological, functional and tissue modifications affecting the heart and the cardiovascular system. Advanced imaging techniques, such as speckle tracking and three-dimensional echocardiography, cardiac magnetic resonance, computed tomography and PET-computed tomography, are able to identify cardiovascular injury at different stages of arterial hypertension, from subclinical alterations and overt organ damage to possible complications related to pressure overload, thus giving a precious contribution for guiding timely and appropriate management and therapy, in order to improve diagnostic accuracy and prevent disease progression. The present review focuses on the peculiarity of different advanced imaging tools to provide information about different and multiple morphological and functional aspects involved in hypertensive cardiovascular injury. This evaluation emphasizes the usefulness of the emerging multiimaging approach for a comprehensive overview of arterial hypertension induced cardiovascular damage