The Inflammatory Profile of the Tumor Microenvironment, Orchestrated by Cyclooxygenase-2, Promotes Epithelial-Mesenchymal Transition

Microbial infections are a major public health concern. Antimicrobial peptides (AMPs) have been demonstrated to be a plausible alternative to the current arsenal of drugs that has become inefficient due to multidrug resistance. Herein we describe a new AMP family, namely the super-cationic peptide dendrimers (SCPDs). Although all members of the series exert some antibacterial activity, we propose that special attention should be given to (KLK)2KLLKLL-NH2 (G1KLK-L2KL2), which shows selectivity for Gram-negative bacteria and virtually no cytotoxicity in HepG2 and HEK293. These results reinforce the validity of the SCPD family as a valuable class of AMP and support G1KLK-L2KL2 as a strong lead candidate for the future development of an antibacterial agent against Gram-negative bacteria

Selective targeting of bioengineered platelets to prostate cancer vasculature: new paradigm for therapeutic modalities

Androgen deprivation therapy (ADT) provides palliation for most patients with advanced prostate cancer (CaP); however, greater than 80% subsequently fail ADT. ADT has been indicated to induce an acute but transient destabilization of the prostate vasculature in animal models and humans. Human re-hydrated lyophilized platelets (hRL-P) were investigated as a prototype for therapeutic agents designed to target selectively the tumour-associated vasculature in CaP. The ability of hRL-P to bind the perturbed endothelial cells was tested using thrombin- and ADP-activated human umbilical vein endothelial cells (HUVEC), as well as primary xenografts of human prostate tissue undergoing acute vascular involution in response to ADT. hRL-P adhered to activated HUVEC in a dose-responsive manner. Systemically administered hRL-P, and hRL-P loaded with super-paramagnetic iron oxide (SPIO) nanoparticles, selectively targeted the ADT-damaged human microvasculature in primary xenografts of human prostate tissue. This study demonstrated that hRL-P pre-loaded with chemo-therapeutics or nanoparticles could provide a new paradigm for therapeutic modalities to prevent the rebound/increase in prostate vasculature after ADT, inhibiting the transition to castration-recurrent growth

Bone Marrow Stromal Cells Modulate Mouse ENT1 Activity and Protect Leukemia Cells from Cytarabine Induced Apoptosis

BACKGROUND: Despite a high response rate to chemotherapy, the majority of patients with acute myeloid leukemia (AML) are destined to relapse due to residual disease in the bone marrow (BM). The tumor microenvironment is increasingly being recognized as a critical factor in mediating cancer cell survival and drug resistance. In this study, we propose to identify mechanisms involved in the chemoprotection conferred by the BM stroma to leukemia cells. METHODS: Using a leukemia mouse model and a human leukemia cell line, we studied the interaction of leukemia cells with the BM microenvironment. We evaluated in vivo and in vitro leukemia cell chemoprotection to different cytotoxic agents mediated by the BM stroma. Leukemia cell apoptosis was assessed by flow cytometry and western blotting. The activity of the equilibrative nucleoside transporter 1 (ENT1), responsible for cytarabine cell incorporation, was investigated by measuring transport and intracellular accumulation of (3)H-adenosine. RESULTS: Leukemia cell mobilization from the bone marrow into peripheral blood in vivo using a CXCR4 inhibitor induced chemo-sensitization of leukemia cells to cytarabine, which translated into a prolonged survival advantage in our mouse leukemia model. In vitro, the BM stromal cells secreted a soluble factor that mediated significant chemoprotection to leukemia cells from cytarabine induced apoptosis. Furthermore, the BM stromal cell supernatant induced a 50% reduction of the ENT1 activity in leukemia cells, reducing the incorporation of cytarabine. No protection was observed when radiation or other cytotoxic agents such as etoposide, cisplatin and 5-fluorouracil were used. CONCLUSION: The BM stroma secretes a soluble factor that significantly protects leukemia cells from cytarabine-induced apoptosis and blocks ENT1 activity. Strategies that modify the chemo-protective effects mediated by the BM microenvironment may enhance the benefit of conventional chemotherapy for patients with AML

Primary Xenografts of Human Prostate Tissue as a Model to Study Angiogenesis Induced by Reactive Stroma

Characterization of the mechanism(s) of androgen-driven human angiogenesis could have significant implications for modeling new forms of anti-angiogenic therapies for CaP and for developing targeted adjuvant therapies to improve efficacy of androgen-deprivation therapy. However, models of angiogenesis by human endothelial cells localized within an intact human prostate tissue architecture are until now extremely limited. This report characterizes the burst of angiogenesis by endogenous human blood vessels in primary xenografts of fresh surgical specimens of benign prostate or prostate cancer (CaP) tissue that occurs between Days 6–14 after transplantation into SCID mice pre-implanted with testosterone pellets. The wave of human angiogenesis was preceded by androgen-mediated up-regulation of VEGF-A expression in the stromal compartment. The neo-vessel network anastomosed to the host mouse vascular system between Days 6–10 post-transplantation, the angiogenic response ceased by Day 15, and by Day 30 the vasculature had matured and stabilized, as indicated by a lack of leakage of serum components into the interstitial tissue space and by association of nascent endothelial cells with mural cells/pericytes. The angiogenic wave was concurrent with the appearance of a reactive stroma phenotype, as determined by staining for α-SMA, Vimentin, Tenascin, Calponin, Desmin and Masson's trichrome, but the reactive stroma phenotype appeared to be largely independent of androgen availability. Transplantation-induced angiogenesis by endogenous human endothelial cells present in primary xenografts of benign and malignant human prostate tissue was preceded by induction of androgen-driven expression of VEGF by the prostate stroma, and was concurrent with and the appearance of a reactive stroma phenotype. Androgen-modulated expression of VEGF-A appeared to be a causal regulator of angiogenesis, and possibly of stromal activation, in human prostate xenografts

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Regulation of adenosine transport by D-glucose in human fetal endothelial cells: involvement of nitric oxide, protein kinase C and mitogen-activated protein kinase

The effects of elevated D-glucose on adenosine transport were investigated in human cultured umbilical vein endothelial cells isolated from normal pregnancies.Elevated D-glucose resulted in a time- (8-12 h) and concentration-dependent (half-maximal at 10 ± 2 mM) inhibition of adenosine transport, which was associated with a reduction in the Vmax for nitrobenzylthioinosine (NBMPR)-sensitive (es) saturable nucleoside with no significant change in Km. D-Fructose (25 mM), 2-deoxy-D-glucose (25 mM) or D-mannitol (20 mM) had no effect on adenosine transport.Adenosine transport was inhibited following incubation of cells with the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA; 100 nM, 30 min to 24 h). D-Glucose-induced inhibition of transport was abolished by calphostin C (100 nM, an inhibitor of PKC), and was not further reduced by PMA.Increased PKC activity in the membrane (particulate) fraction of endothelial cells exposed to D-glucose or PMA was blocked by calphostin C but was unaffected by NG-nitro-L-arginine methyl ester (L-NAME; 100 μM, an inhibitor of nitric oxide synthase (NOS)) or PD-98059 (10 μM, an inhibitor of mitogen-activated protein kinase kinase 1).D-Glucose and PMA increased endothelial NOS (eNOS) activity, which was prevented by calphostin C or omission of extracellular Ca2+ and unaffected by PD-98059.Adenosine transport was inhibited by S-nitroso-N-acetyl-l,D-penicillamine (SNAP; 100 μM, an NO donor) but was increased in cells incubated with L-NAME. The effect of SNAP on adenosine transport was abolished by PD-98059.Phosphorylation of mitogen-activated protein kinases p44mapk (ERK1) and p42mapk (ERK2) was increased in endothelial cells exposed to elevated D-glucose (25 mM for 30 min to 24 h) and the NO donor SNAP (100 μM, 30 min). The effect of D-glucose was blocked by PD-98059 or L-NAME, which also prevented the inhibition of adenosine transport mediated by elevated D-glucose.Our findings provide evidence that D-glucose inhibits adenosine transport in human fetal endothelial cells by a mechanism that involves activation of PKC, leading to increased NO levels and p42-p44mapk phosphorylation. Thus, the biological actions of adenosine appear to be altered under conditions of sustained hyperglycaemia

The angiogenic burst in primary xenografts of prostate tissue is preceded by androgen-modulated up-regulation of VEGF-A gene expression in the stromal compartment.

<p>(<b>a</b>). PCR analysis of expression of transcripts for pro-angiogenic factors in initial prostate tissue specimens before transplantation, and in corresponding primary xenografts after transplantation. Total RNA was extracted from initial prostate tissue (IT), and from prostate xenografts on different days after transplantation (d1–d14). GADPH was used as an internal control. (<b>b</b>). Immuno-histochemical identification of human VEGF protein in primary xenografts of prostate tissue over the 14 days after transplantation (d1–d14) in host mice pre-implanted with (+T), or not pre-implanted with (−T), sustained-release testosterone pellets. Bars = 50 µm.</p

Primary xenografts of human prostate tissue maintain the <i>in vivo</i> tissue architecture and expression of key prostatic markers.

<p>Immuno-histochemical identification of protein expression of androgen receptor (AR), prostate-specific antigen (PSA) and pan-cytokeratin (Cyt) visualized by peroxidase staining demonstrated the level of expression remained constant over the fourteen days post-transplantation (1–14).</p

Determination of hypoxic areas, and of expression of HIF-1α, HIF-2α and GLUT1 in primary xenografts of human prostate.

<p>Animals were administered Hypoxyprobe-1 (HyPo-P, NPI Inc.) via <i>i.p</i> injection (60 mg/100 g body weight) on select days after tissue transplantation. One hour after injection, the prostate xenografts were harvested and hypoxic areas visualized using a monoclonal antibody specific for Hypoxyprobe-1. Immuno-histochemical identification of changes in human HIF-1α, HIF-2α and GLUT1 protein levels in primary xenografts of human prostate tissue over the 4 days after tissue transplantation (1–4). Hypoxic areas, and human HIF-1α, HIF-2α, and GLUT1 protein, were visualized using DAB and hydrogen peroxide.</p