Glutamate signaling in human melanoma cell line SK-MEL-28

Glutamate, recognized as the major excitatory neurotransmitter in the mammalian central nervous system, has been shown to regulate proliferation, migration and survival of immature and mature neurons. In addition, glutamate exerts regulatory roles in the physiology of non-neuronal cells, as confirmed by its expression in peripheral tissues [1]. Recently, the involvement of both ionotropic and metabotropic glutamate receptors in the pathophysiology of various human malignancies such as melanoma has been proposed [2]. In this study, we investigate the role of ionotropic NMDA and AMPA receptors in human melanoma cell line SK-MEL-28, via the evaluation of gene expression profile of markers for neural crest (Slug, Snail, Twist), mesenchymal stem cell (Vimentin) and embryonic stem cell (Nanog and Oct4). We reported significant alterations in neural crest and embryonic stem cell markers expression in SK-MEL-28 following stimulation with 10 or 100 mM AMPA or NMDA. In addition, modulatory actions of glutamate receptors on cell proliferation and migration were also demonstrated via in vitro proliferation assay and wound healing assay. Overall, our results enhance the knowledge of glutamate signaling in human melanoma

Iron-mediated oxidative stress induces PD-L1 expression via activation of c-Myc in lung adenocarcinoma

Introduction: The PD-1/PD-L1 axis is hijacked by lung adenocarcinoma (LUAD) cells to escape immune surveillance. PD-L1 expression in LUAD is affected, among others, by the metabolic trafficking between tumor cells and the tumor microenvironment (TME). Methods: Correlation between PD-L1 expression and iron content within the TME was established on FFPE LUAD tissue samples. The effects of an iron rich microenvironment on PD-L1 mRNA and protein levels were assessed in vitro in H460 and A549 LUAD by using qPCR, western blot and flow citometry. c-Myc knockdown was performed to validate the role of this transcription factor on PD-L1 expression. The effects of iron-induced PD-L1 on T cell immune function was assessed by quantifying IFN-γ release in a co-colture system. TCGA dataset was used to analyse the correlation between PD-L1 and CD71 mRNA expression in LUAD patients. Results: In this study, we highlight a significant correlation between iron density within the TME and PD-L1 expression in 16 LUAD tissue specimens. In agreement, we show that a more pronounced innate iron-addicted phenotype, indicated by a higher transferrin receptor CD71 levels, significantly correlates with higher PD-L1 mRNA expression levels in LUAD dataset obtained from TCGA database. In vitro, we demonstrate that the addition of Fe3+ within the culture media promotes the significant overexpression of PD-L1 in A549 and H460 LUAD cells, through the modulation of its gene transcription mediated by c-Myc. The effects of iron lean on its redox activity since PD-L1 up-regulation is counteracted by treatment with the antioxidant compound trolox. When LUAD cells are co-cultured with CD3/CD28-stimulated T cells in an iron-rich culture condition, PD-L1 up-regulation causes the inhibition of T-lymphocytes activity, as demonstrated by the significant reduction of IFN-γ release. Discussion: Overall, in this study we demonstrate that iron abundance within the TME may enhance PD-L1 expression in LUAD and, thus, open the way for the identification of possible combinatorial strategies that take into account the iron levels within the TME to improve the outcomes of LUAD patients treated with anti-PD-1/PD-L1-based therapies

Hypoxia induces Galectin-3 and Bcl-2 over-expression in human umbilical vein endothelial cells (HUVECs)

Angiogenesis, the growth of new blood vessels from pre-existing endothelium, is a critical phenomenon occurring during development and tissue regeneration. In pathological conditions such as inflammation and malignancies, hypoxia represent one of the most important driver of angiogenesis, mainly via the release of nitric oxide [1]. Here we investigate the behavior of human umbilical vein endothelial cells (HUVECs) treated with 100 mM CoCl2 for 24 hours, a condition mimicking hypoxia by the stabilization of HIF-1α and HIF-2α [2,3]. MTT and wound healing assays were performed to evaluate cell migration and proliferation, respectively, while Bcl-2 and Galectin-3 expression levels were analyzed by western blotting. We showed that hypoxic condition resulted in reduced proliferation and migration with increased expression of Galectin-3 and Bcl-2. These preliminary results provide new insights in the characterization of Galectin-3/Bcl-2 interplay in endothelial cell survival under hypoxic condition, and will contribute to a better understanding of hypoxia influences on tumor angiogenesis

Erectile dysfunction of sclerodermic patients correlates with digital vascular damage

Background: The prevalence of erectile dysfunction (ED) in men with systemic sclerosis (SSc) can be considered a manifestation of endothelium damage. Aim of the study is to investigate ED in SSc patients by color Doppler ultrasound examination and to correlate it with disease severity and digital vascular damage. Methods: In 20 males SSc patients blood flow velocity in the cavernous artery was determined with Duplex ultrasonography. Naifold videocapillaroscopy, Sexual Health Inventory for Men (SHIM) and Medsger Disease Severity Scale (DSS) were performed. Arteriogenic ED was defined by the presence of a reduced peak systolic velocity (PSVs), while diastolic velocity (EDV) and the resistive index (RI) were estimated to evaluate venocclusive dysfunction. SSc patients are classified by capillaroscopic pattern and vascular domain of DSS into two groups: low vascular damage (early or active capillaroscopic pattern and score of vascular domain of DSS = 3). Results: In all SSc patients a reduction of SHIM is present (mean 13.5 +/- 6.3). Patients with less vascular damage have a significantly (p0.5) between the two groups of vascular damage was found in PSVs. Venocclusive dysfunction was present only (p<0.001) in the group with high vascular damage. Conclusion: We can assert that there is a relationship between SSc vascular digital damage and ED. (C) 2010 European Federation of Internal Medicine. Published by Elsevier B. V. All rights reserved

Immunity to infections after haploidentical hematopoietic stem cell transplantation

The advantage of using a Human Leukocyte Antigen (HLA)-mismatched related donor is that almost every patient who does not have an HLA-identical donor or who urgently needs hematopoietic stem cell transplantation (HSCT) has at least one family member with whom shares one haplotype (haploidentical) and who is promptly available as a donor. The major challenge of haplo-HSCT is intense bi-directional alloreactivity leading to high incidences of graft rejection and graft-versus-host disease (GVHD). Advances in graft processing and pharmacologic prophylaxis of GVHD have reduced these risks and have made haplo-HSCT a viable alternative for patients lacking a matched donor. Indeed, the haplo-HSCT has spread to centers worldwide even though some centers have preferred an approach based on T cell depletion of G-CSF-mobilized peripheral blood progenitor cells (PBPCs), others have focused on new strategies for GvHD prevention, such as G-CSF priming of bone marrow and robust post-transplant immune suppression or post-transplant cyclophosphamide (PTCY). Today, the graft can be a megadose of T-cell depleted PBPCs or a standard dose of unmanipulated bone marrow and/or PBPCs. Although haplo-HSCT modalities are based mainly on high intensity conditioning regimens, recently introduced reduced intensity regimens (RIC) showed promise in decreasing early transplant-related mortality (TRM), and extending the opportunity of HSCT to an elderly population with more comorbidities. Infections are still mostly responsible for toxicity and non-relapse mortality due to prolonged immunosuppression related, or not, to GVHD. Future challenges lie in determining the safest preparative conditioning regimen, minimizing GvHD and promoting rapid and more robust immune reconstitution

Ferroptosis and Cancer: Mitochondria Meet the “Iron Maiden” Cell Death

Ferroptosis is a new type of oxidative regulated cell death (RCD) driven by iron-dependent lipid peroxidation. As major sites of iron utilization and master regulators of oxidative metabolism, mitochondria are the main source of reactive oxygen species (ROS) and, thus, play a role in this type of RCD. Ferroptosis is, indeed, associated with severe damage in mitochondrial morphology, bioenergetics, and metabolism. Furthermore, dysregulation of mitochondrial metabolism is considered a biochemical feature of neurodegenerative diseases linked to ferroptosis. Whether mitochondrial dysfunction can, per se, initiate ferroptosis and whether mitochondrial function in ferroptosis is context-dependent are still under debate. Cancer cells accumulate high levels of iron and ROS to promote their metabolic activity and growth. Of note, cancer cell metabolic rewiring is often associated with acquired sensitivity to ferroptosis. This strongly suggests that ferroptosis may act as an adaptive response to metabolic imbalance and, thus, may constitute a new promising way to eradicate malignant cells. Here, we review the current literature on the role of mitochondria in ferroptosis, and we discuss opportunities to potentially use mitochondria-mediated ferroptosis as a new strategy for cancer therapy

Chemoresistance in H-Ferritin Silenced Cells: The Role of NF-κB

Nuclear Factor-&kappa;B (NF-&kappa;B) is frequently activated in tumor cells contributing to aggressive tumor growth and resistance to chemotherapy. Here we demonstrate that Ferritin Heavy Chain (FHC) protein expression inversely correlates with NF-&kappa;B activation in cancer cell lines. In fact, FHC silencing in K562 and SKOV3 cancer cell lines induced p65 nuclear accumulation, whereas FHC overexpression correlated with p65 nuclear depletion in the same cell lines. In FHC-silenced cells, the p65 nuclear accumulation was reverted by treatment with the reactive oxygen species (ROS) scavenger, indicating that NF-&kappa;B activation was an indirect effect of FHC on redox metabolism. Finally, FHC knock-down in K562 and SKOV3 cancer cell lines resulted in an improved cell viability following doxorubicin or cisplatin treatment, being counteracted by the transient expression of inhibitory of NF-&kappa;B, I&kappa;B&alpha;. Our results provide an additional layer of information on the complex interplay of FHC with cellular metabolism, and highlight a novel scenario of NF-&kappa;B-mediated chemoresistance triggered by the downregulation of FHC with potential therapeutic implications

Author response: Lipid droplets and ferritin heavy chain: a devilish liaison in human cancer cell radioresistance

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Maintenance of renal function in a patient with a history of acute paroxysmal nocturnal hemoglobinuria-associated kidney injury

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening blood disorder characterized by intravascular hemolysis, thrombosis and bone marrow failure. Acute kidney injury, including acute renal failure, have been reported in patients with PNH. We report the case of a 36-year-old male patient with PNH who developed acute kidney injury following an infection of undetermined diagnosis. Although hemolysis was initially controlled and renal function stabilized following packed red blood cell transfusion and empirical levofloxacin and prednisone, he later experienced recurrent episodes of hemolysis and hematuria requiring monthly red blood cell support. Given the high risk of thromboembolic events, treatment with standard-dose eculizumab was started. The patient's hematologic values improved, renal function was maintained, and no thromboembolic events occurred