Carriers for hydrophobic drug molecules: lipid-coated hollow mesoporous silica particles, and the influence of shape and size on encapsulation efficiency

Hydrophobic drugs, while designed to interact with specific receptors or enzymes located in lipid-rich cell membranes, often face challenges of limited bioavailability and insufficient circulation time due to their insolubility in aqueous environments. One plausible pathway to increase their blood circulation time is to load these drugs into biocompatible and hydrophilic carriers to enhance their uptake. In this study, mesoporous silica (mSiO2) nanocarriers of various morphologies (including cubes, capsules, and spheres) were synthesized. These nanocarriers were then surface-functionalized with alkyl chain hydrocarbons, specifically octadecyl-trimethoxysilane, (OCH3)3Si(CH2)17CH3, to render them hydrophobic. The resulting nanocarriers (((OCH3)3Si(CH2)17CH3)@mSiO2) showed up to 80% uptake for hydrophobic drugs. However, a significant drawback was observed as most of the drugs were prone to uncontrollable release within 6 h. This challenge of premature drug release was successfully mitigated by effectively sealing the drug-loaded nanocarriers with a pH-sensitive lipid overlayer. The lipid-coated nanocarriers prolonged drug containment and sustained release up to 72 h, compared to 6 h for uncoated nanocarriers, thereby facilitating longer blood circulation times. Moreover, the shape and size of nanocarriers were found to influence both drug entrapment capacity and release behavior with cubic forms exhibiting superior loading capacity due to higher surface area and porosity. Additionally, it was observed that the molecular weight and chemical structure of the drug molecules played a crucial role in determining their uptake and release profiles. Furthermore, the influence of different morphologies of nanocarriers on cell uptake and cytotoxicity in immune cells was elucidated. These findings underscore the importance of nanocarrier morphology and drug properties to enhance loading capacities and controlled release profiles, for designing drug delivery systems tailored for hydrophobic drugs.

Role of the tumor microenvironment in CLL pathogenesis

Chronic lymphocytic leukemia (CLL) cells extensively interact with and depend on their surrounding tumor microenvironment (TME). The TME encompasses a heterogeneous array of cell types, soluble signals, and extracellular vesicles, which contribute significantly to CLL pathogenesis. CLL cells and the TME cooperatively generate a chronic inflammatory milieu, which reciprocally reprograms the TME and activates a signaling network within CLL cells, promoting their survival and proliferation. Additionally, the inflammatory milieu exerts chemotactic effects, attracting CLL cells and other immune cells to the lymphoid tissues. The intricate CLL-TME interactions also facilitate immune evasion and compromise leukemic cell surveillance. We also review recent advances that have shed light on additional aspects that are substantially influenced by the CLL-TME interplay.

LYN kinase programs stromal fibroblasts to facilitate leukemic survival via regulation of c-JUN and THBS1

Microenvironmental bystander cells are essential for the progression of chronic lymphocytic leukemia (CLL). We have discovered previously that LYN kinase promotes the formation of a microenvironmental niche for CLL. Here we provide mechanistic evidence that LYN regulates the polarization of stromal fibroblasts to support leukemic progression. LYN is overexpressed in fibroblasts of lymph nodes of CLL patients. LYN-deficient stromal cells reduce CLL growth in vivo. LYN-deficient fibroblasts show markedly reduced leukemia feeding capacity in vitro. Multi-omics profiling reveals that LYN regulates the polarization of fibroblasts towards an inflammatory cancer-associated phenotype through modulation of cytokine secretion and extracellular matrix composition. Mechanistically, LYN deletion reduces inflammatory signaling including reduction of c-JUN expression, which in turn augments the expression of Thrombospondin-1, which binds to CD47 thereby impairing CLL viability. Together, our findings suggest that LYN is essential for rewiring fibroblasts towards a leukemia-supportive phenotype.

Stromal cells support the survival of human primary chronic lymphocytic leukemia (CLL) cells through Lyn-driven extracellular vesicles

Introduction

In chronic lymphocytic leukemia (CLL), the tumor cells receive survival support from stromal cells through direct cell contact, soluble factors and extracellular vesicles (EVs). The protein tyrosine kinase Lyn is aberrantly expressed in the malignant and stromal cells in CLL tissue. We studied the role of Lyn in the EV-based communication and tumor support.

Methods

We compared the Lyn-dependent EV release, uptake and functionality using Lyn-proficient (wild-type) and -deficient stromal cells and primary CLL cells.

Results

Lyn-proficient cells caused a significantly higher EV release and EV uptake as compared to Lyn-deficient cells and also conferred stronger support of primary CLL cells. Proteomic comparison of the EVs from Lyn-proficient and -deficient stromal cells revealed 70 significantly differentially expressed proteins. Gene ontology studies categorized many of which to organization of the extracellular matrix, such as collagen, fibronectin, fibrillin, Lysyl oxidase like 2, integrins and endosialin (CD248). In terms of function, a knockdown of CD248 in Lyn⁺ HS-5 cells resulted in a diminished B-CLL cell feeding capacity compared to wildtype or scrambled control cells. CD248 is a marker of certain tumors and cancer-associated fibroblast (CAF) and crosslinks fibronectin and collagen in a membrane-associated context.

Conclusion

Our data provide preclinical evidence that the tyrosine kinase Lyn crucially influences the EV-based communication between stromal and primary B-CLL cells by raising EV release and altering the concentration of functional molecules of the extracellular matrix.

Distinct Genetically Determined Origins of Myd88/BCL2-Driven Aggressive Lymphoma Rationalize Targeted Therapeutic Intervention Strategies

Genomic profiling revealed the identity of at least 5 subtypes of diffuse large B-cell lymphoma (DLBCL), including the MCD/C5 cluster characterized by aberrations in MYD88, BCL2, PRDM1, and/or SPIB. We generated mouse models harboring B cell-specific Prdm1 or Spib aberrations on the background of oncogenic Myd88 and Bcl2 lesions. We deployed whole-exome sequencing, transcriptome, flow-cytometry, and mass cytometry analyses to demonstrate that Prdm1- or Spib-altered lymphomas display molecular features consistent with prememory B cells and light-zone B cells, whereas lymphomas lacking these alterations were enriched for late light-zone and plasmablast-associated gene sets. Consistent with the phenotypic evidence for increased B cell receptor signaling activity in Prdm1-altered lymphomas, we demonstrate that combined BTK/BCL2 inhibition displays therapeutic activity in mice and in five of six relapsed/refractory DLBCL patients. Moreover, Prdm1-altered lymphomas were immunogenic upon transplantation into immuno-competent hosts, displayed an actionable PD-L1 surface expression, and were sensitive to antimurine-CD19-CAR-T cell therapy, in vivo.

SIGNIFICANCE

Relapsed/refractory DLBCL remains a major medical challenge, and most of these patients succumb to their disease. Here, we generated mouse models, faithfully recapitulating the biology of MYD88-driven human DLBCL. These models revealed robust preclinical activity of combined BTK/BCL2 inhibition. We confirmed activity of this regimen in pretreated non-GCB-DLBCL patients. See related commentary by Leveille et al., p. 8. This article is highlighted in the In This Issue feature, p. 1.

Non-viral TRAC-knocked-in CD19KICAR-T and gp350KICAR-T cells tested against Burkitt lymphomas with type 1 or 2 EBV infection: In vivo cellular dynamics and potency

Introduction

The ubiquitous Epstein-Barr virus (EBV) is an oncogenic herpes virus associated with several human malignancies. EBV is an immune-evasive pathogen that promotes CD8⁺ T cell exhaustion and dysregulates CD4⁺ T cell functions. Burkitt lymphoma (BL) is frequently associated with EBV infections. Since BL relapses after conventional therapies are difficult to treat, we evaluated prospective off-the-shelf edited CAR-T cell therapies targeting CD19 or the EBV gp350 cell surface antigen.

Methods

We used CRISPR/Cas9 gene editing methods to knock in (KI) the CD19CAR.CD28z or gp350CAR.CD28z into the T cell receptor (TCR) alpha chain (TRAC) locus.

Results

Applying upscaled methods with the ExPERT ATx^® MaxCyte system, KI efficacy was ~20% of the total ~2 × 10⁸ TCR-knocked-out (KO) generated cells. ^KOTCR^KICAR-T cells were co-cultured in vitro with the gp350⁺CD19⁺ BL cell lines Daudi (infected with type 1 EBV) or with Jiyoye (harboring a lytic type 2 EBV). Both types of CAR-T cells showed cytotoxic effects against the BL lines in vitro. CD8^{+ KI}CAR-T cells showed higher persistency than CD4^{+ KI}CAR-T cells after in vitro co-culture with BL and upregulation of the activation/exhaustion markers PD-1, LAG-3, and TIM-3. Two preclinical in vivo xenograft models were set up with Nod.Rag.Gamma mice injected intravenously (i.v.) with 2 × 10⁵ Daudi/fLuc-GFP or with Jiyoye/fLuc-GFP cells. Compared with the non-treated controls, mice challenged with BL and treated with CD19^KICAR-T cells showed delayed lymphoma dissemination with lower EBV DNA load. Notably, for the Jiyoye/fLuc-GFP model, almost exclusively CD4⁺ CD19^KICAR-T cells were detectable at the endpoint analyses in the bone marrow, with increased frequencies of regulatory T cells (T_regs) and TIM-3⁺CD4⁺ T cells. Administration of gp350^KICAR-T cells to mice after Jiyoye/GFP-fLuc challenge did not inhibit BL growth in vivo but reduced the EBV DNA load in the bone marrow and promoted gp350 antigen escape. CD8⁺PD-1⁺LAG-3⁺ gp350^KICAR-T cells were predominant in the bone marrow.

Discussion

The two types of ^KOTCR^KICAR-T cells showed different therapeutic effects and in vivo dynamics. These findings reflect the complexities of the immune escape mechanisms of EBV, which may interfere with the CAR-T cell property and potency and should be taken into account for future clinical translation.

Spleen tyrosine kinase mediates innate and adaptive immune crosstalk in SARS-CoV-2 mRNA vaccination

Durable cell‐mediated immune responses require efficient innate immune signaling and the release of pro‐inflammatory cytokines. How precisely mRNA vaccines trigger innate immune cells for shaping antigen specific adaptive immunity remains unknown. Here, we show that SARS‐CoV‐2 mRNA vaccination primes human monocyte‐derived macrophages for activation of the NLRP3 inflammasome. Spike protein exposed macrophages undergo NLRP3‐driven pyroptotic cell death and subsequently secrete mature interleukin‐1β. These effects depend on activation of spleen tyrosine kinase (SYK) coupled to C‐type lectin receptors. Using autologous cocultures, we show that SYK and NLRP3 orchestrate macrophage‐driven activation of effector memory T cells. Furthermore, vaccination‐induced macrophage priming can be enhanced with repetitive antigen exposure providing a rationale for prime‐boost concepts to augment innate immune signaling in SARS‐CoV‐2 vaccination. Collectively, these findings identify SYK as a regulatory node capable of differentiating between primed and unprimed macrophages, which modulate spike protein‐specific T cell responses.

The scaffold protein NEDD9 is necessary for leukemia-cell migration and disease progression in a mouse model of chronic lymphocytic leukemia

The scaffold protein NEDD9 is frequently upregulated and hyperphosphorylated in cancers, and is associated with poor clinical outcome. NEDD9 promotes B-cell adhesion, migration and chemotaxis, pivotal processes for malignant development. We show that global or B-cell-specific deletion of Nedd9 in chronic lymphocytic leukemia (CLL) mouse models delayed CLL development, markedly reduced disease burden and resulted in significant survival benefit. NEDD9 was required for efficient CLL cell homing, chemotaxis, migration and adhesion. In CLL patients, peripheral NEDD9 expression was associated with adhesion and migration signatures as well as leukocyte count. Additionally, CLL lymph nodes frequently expressed high NEDD9 levels, with a subset of patients showing NEDD9 expression enriched in the CLL proliferation centers. Blocking activity of prominent NEDD9 effectors, including AURKA and HDAC6, effectively reduced CLL cell migration and chemotaxis. Collectively, our study provides evidence for a functional role of NEDD9 in CLL pathogenesis that involves intrinsic defects in adhesion, migration and homing.

CD30-Positive Extracellular Vesicles Enable the Targeting of CD30-Negative DLBCL Cells by the CD30 Antibody-Drug Conjugate Brentuximab Vedotin

CD30, a member of the TNF receptor superfamily, is selectively expressed on a subset of activated lymphocytes and on malignant cells of certain lymphomas, such as classical Hodgkin Lymphoma (cHL), where it activates critical bystander cells in the tumor microenvironment. Therefore, it is not surprising that the CD30 antibody-drug conjugate Brentuximab Vedotin (BV) represents a powerful, FDA-approved treatment option for CD30⁺ hematological malignancies. However, BV also exerts a strong anti-cancer efficacy in many cases of diffuse large B cell lymphoma (DLBCL) with poor CD30 expression, even when lacking detectable CD30⁺ tumor cells. The mechanism remains enigmatic. Because CD30 is released on extracellular vesicles (EVs) from both, malignant and activated lymphocytes, we studied whether EV-associated CD30 might end up in CD30^– tumor cells to provide binding sites for BV. Notably, CD30⁺ EVs bind to various DLBCL cell lines as well as to the FITC-labeled variant of the antibody-drug conjugate BV, thus potentially conferring the BV binding also to CD30^– cells. Confocal microscopy and imaging cytometry studies revealed that BV binding and uptake depend on CD30⁺ EVs. Since BV is only toxic toward CD30^– DLBCL cells when CD30⁺ EVs support its uptake, we conclude that EVs not only communicate within the tumor microenvironment but also influence cancer treatment. Ultimately, the CD30-based BV not only targets CD30⁺ tumor cell but also CD30^– DLBCL cells in the presence of CD30⁺ EVs. Our study thus provides a feasible explanation for the clinical impact of BV in CD30^– DLBCL and warrants confirming studies in animal models.

Features of the Energy Spectrum of Cosmic Rays above 2.5×10^{18} eV Using the Pierre Auger Observatory

We report a measurement of the energy spectrum of cosmic rays above 2.5×10^{18}  eV based on 215 030 events. New results are presented: at about 1.3×10^{19}  eV, the spectral index changes from 2.51±0.03(stat)±0.05(syst) to 3.05±0.05(stat)±0.10(syst), evolving to 5.1±0.3(stat)±0.1(syst) beyond 5×10^{19}  eV, while no significant dependence of spectral features on the declination is seen in the accessible range. These features of the spectrum can be reproduced in models with energy-dependent mass composition. The energy density in cosmic rays above 5×10^{18}  eV is [5.66±0.03(stat)±1.40(syst)]×10^{53}  erg Mpc^{-3}.

Meta-Analysis Reveals Significant Sex Differences in Chronic Lymphocytic Leukemia Progression in the Eµ-TCL1 Transgenic Mouse Model

The Eµ-TCL1 transgenic mouse model represents the most widely and extensively used animal model for chronic lymphocytic leukemia (CLL). In this report, we performed a meta-analysis of leukemia progression in over 300 individual Eµ-TCL1 transgenic mice and discovered a significantly accelerated disease progression in females compared to males. This difference is also reflected in an aggressive CLL mouse model with additional deletion of Tp53 besides the TCL1 transgene. Moreover, after serial adoptive transplantation of murine CLL cells, female recipients also succumbed to CLL earlier than male recipients. This sex-related disparity in the murine models is markedly contradictory to the human CLL condition. Thus, due to our observation we urge both careful consideration in the experimental design and accurate description of the Eµ-TCL1 transgenic cohorts in future studies.

CD74 is dispensable for development of chronic lymphocytic leukemia in Eµ-TCL1 transgenic mice

CD74 is a surface protein expressed on immune cells, which acts as receptor for the chemokine macrophage migration inhibitory factor (MIF). Signaling via the MIF/CD74-axis has been reported to be important for the pathogenesis of chronic lymphocytic leukemia (CLL). We wanted to clarify the role of CD74 in MIF-induced signaling/leukemic development. In Eμ-TCL1 transgenic mice, occurrence of the leukemic phenotype was associated with increased surface CD74 expression. Eμ-TCL1^+/+Cd74^-/- mice showed similar kinetics and clinical features of CLL development as Eμ-TCL1^+/+ mice. MIF stimulation of leukemic splenocytes led to AKT activation in a CD74-dependent manner. AKT activation was reduced in Cd74-deficient splenocytes in the presence of the oncogenic TCL1-transgene. Tumor cell apoptosis/proliferation were unaffected in Eμ-TCL1^+/+Cd74^-/- mice. Our data suggest that the need for active CD74 signaling is overcome in the leukemic context of TCL1-driven CLL, and that CD74 may have a dispensable role for CLL pathogenesis in this model.

Extracellular vesicle measurements with nanoparticle tracking analysis - An accuracy and repeatability comparison between NanoSight NS300 and ZetaView

The expanding field of extracellular vesicle (EV) research needs reproducible and accurate methods to characterize single EVs. Nanoparticle Tracking Analysis (NTA) is commonly used to determine EV concentration and diameter. As the EV field is lacking methods to easily confirm and validate NTA data, questioning the reliability of measurements remains highly important. In this regard, a comparison addressing measurement quality between different NTA devices such as Malvern’s NanoSight NS300 or Particle Metrix’ ZetaView has not yet been conducted. To evaluate the accuracy and repeatability of size and concentration determinations of both devices, we employed comparative methods including transmission electron microscopy (TEM) and single particle interferometric reflectance imaging sensing (SP-IRIS) by ExoView. Multiple test measurements with nanospheres, liposomes and ultracentrifuged EVs from human serum and cell culture supernatant were performed. Additionally, serial dilutions and freeze-thaw cycle-dependent EV decrease were measured to determine the robustness of each system. Strikingly, NanoSight NS300 exhibited a 2.0–2.1-fold overestimation of polystyrene and silica nanosphere concentration. By measuring serial dilutions of EV samples, we demonstrated higher accuracy in concentration determination by ZetaView (% BIAS range: 2.7–8.5) in comparison with NanoSight NS300 (% BIAS range: 32.9–36.8). The concentration measurements by ZetaView were also more precise (% CV range: 0.0–4.7) than measurements by NanoSight NS300 (% CV range: 5.4–10.7). On the contrary, quantitative TEM imaging indicated more accurate EV sizing by NanoSight NS300 (% D_TEM range: 79.5–134.3) compared to ZetaView (% D_TEM range: 111.8–205.7), while being equally repeatable (NanoSight NS300% CV range: 0.8–6.7; ZetaView: 1.4–7.8). However, both devices failed to report a peak EV diameter below 60 nm compared to TEM and SP-IRIS. Taken together, NTA devices differ strongly in their hardware and software affecting measuring results. ZetaView provided a more accurate and repeatable depiction of EV concentration, whereas NanoSight NS300 supplied size measurements of higher resolution.

New roles for B cell receptor associated kinases: when the B cell is not the target

Targeting of B cell receptor associated kinases (BAKs), such as Bruton's tyrosine kinase (BTK) or phosphoinositol-3-kinase (PI3K) delta, by specific inhibitors has revolutionized the therapy of B lymphoid malignancies. BAKs are critical signaling transducers of BCR signaling and seem relevant in B cell lymphoma pathogenesis. The functional relevance of BTK for lymphoid malignancies is strongly supported by the observation that resistance to therapy in CLL patients treated with BTK inhibitors such as ibrutinib is often associated with mutations in genes coding for BTK or Phospholipase-C gamma (PLCɣ). In some contrast, next generation sequencing data show that BAKs are mutated at very low frequency in treatment-naïve B cell lymphomas. Therefore, it remains debatable whether BAKs are essential drivers for lymphoma development. In addition, results obtained by targeted deletion of BAKs such as Lyn and Btk in murine CLL models suggest that BAKs may be essential to shape the dialogue between malignant B cells and the tumor microenvironment (TME). Since BAKs are expressed in multiple cell types, BAK inhibitors may disrupt the lymphoma supportive microenvironment. This concept also explains the typical response to BAK inhibitor treatment, characterized by a long-lasting increase of peripheral blood lymphoid cells, due to a redistribution from the lymphoid homing compartments. In addition, BAK inhibitors have shown some efficacy in solid tumors, probably through mediator cells in the TME. This review summarizes and validates the evidence for BAK inhibitors being part of a class of agents that modulate the (hematopoietic) microenvironment of cancers.

ID: 1023 All-trans retinoic acid targets gastric cancer stem cells and inhibits patient-derived gastric carcinoma tumor growth

Gastric carcinoma is the third leading cause of cancer-related death worldwide. This cancer, most of the time metastatic, is essentially treated by surgery associated with conventional chemotherapy, and has a poor prognosis. The existence of cancer stem cells (CSC) expressing CD44 and a high aldehyde dehydrogenase (ALDH) activity has recently been demonstrated in gastric carcinoma and has opened new perspectives to develop targeted therapy. In this study, we evaluated the effects of all-transretinoic acid (ATRA) on CSCs in human gastric carcinoma. ATRA effects were evaluated on the proliferation and tumorigenic properties of gastric carcinoma cells from patient-derived tumors and cell lines in conventional 2D cultures, in 3D culture systems (tumorsphere assay) and in mouse xenograft models. ATRA inhibited both tumorspheres initiation and growth in vitro, which was associated with a cell-cycle arrest through the upregulation of cyclin-dependent kinase (CDK) inhibitors and the downregulation of cell-cycle progression activators. More importantly, ATRA downregulated the expression of the CSC markers CD44 and ALDH as well as stemness genes such as Klf4 and Sox2 and induced differentiation of tumorspheres. Finally, 2 weeks of daily ATRA treatment were sufficient to inhibit gastric tumor progression in vivo, which was associated with a decrease in CD44, ALDH1, Ki67 and PCNA expression in the remaining tumor cells. Administration of ATRA appears to be a potent strategy to efficiently inhibit tumor growth and more importantly to target gastric CSCs in both intestinal and diffuse types of gastric carcinoma.

Two mouse models reveal an actionable PARP1 dependence in aggressive chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) remains an incurable disease. Two recurrent cytogenetic aberrations, namely del(17p), affecting TP53, and del(11q), affecting ATM, are associated with resistance against genotoxic chemotherapy (del17p) and poor outcome (del11q and del17p). Both del(17p) and del(11q) are also associated with inferior outcome to the novel targeted agents, such as the BTK inhibitor ibrutinib. Thus, even in the era of targeted therapies, CLL with alterations in the ATM/p53 pathway remains a clinical challenge. Here we generated two mouse models of Atm- and Trp53-deficient CLL. These animals display a significantly earlier disease onset and reduced overall survival, compared to controls. We employed these models in conjunction with transcriptome analyses following cyclophosphamide treatment to reveal that Atm deficiency is associated with an exquisite and genotype-specific sensitivity against PARP inhibition. Thus, we generate two aggressive CLL models and provide a preclinical rational for the use of PARP inhibitors in ATM-affected human CLL.

ATM and TP53 mutations are associated with poor prognosis in chronic lymphocytic leukaemia (CLL). Here the authors generate mouse models of Tp53- and Atm-defective CLL mimicking the high-risk form of human disease and show that Atm-deficient CLL is sensitive to PARP1 inhibition.

Testing Hadronic Interactions at Ultrahigh Energies with Air Showers Measured by the Pierre Auger Observatory

Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (E_{CM}=110-170  TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory. The average hadronic shower is 1.33±0.16 (1.61±0.21) times larger than predicted using the leading LHC-tuned models EPOS-LHC (QGSJetII-04), with a corresponding excess of muons.

LYN Kinase in the Tumor Microenvironment Is Essential for the Progression of Chronic Lymphocytic Leukemia

Survival of chronic lymphocytic leukemia (CLL) cells strictly depends on the support of an appropriate tumor microenvironment. Here, we demonstrate that LYN kinase is essential for CLL progression. Lyn deficiency results in a significantly reduced CLL burden in vivo. Loss of Lyn within leukemic cells reduces B cell receptor (BCR) signaling including BTK phosphorylation, but surprisingly does not affect leukemic cell expansion. Instead, syngeneic CLL transplantation of CLL cells into Lyn- or Btk-deficient recipients results in a strongly delayed leukemic progression and prolonged survival. Moreover, Lyn deficiency in macrophages hinders nursing functions for CLL cells, which is mediated by direct contact rather than secretion of soluble factors. Taken together, LYN and BTK seem essential for the formation of a microenvironment supporting leukemic growth.

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst)  MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.

Helicobacter pylori generates cells with cancer stem cell properties via epithelial-mesenchymal transition-like changes

Helicobacter pylori infection is the major risk factor for gastric adenocarcinoma. The link with gastric adenocarcinoma is partly due to the H. pylori CagA oncoprotein. CagA is responsible for a particular cell phenotype in vitro, the 'hummingbird' phenotype, that corresponds to an elongation of the cells, mimicking an epithelial-mesenchymal transition (EMT). EMT participates in the carcinogenesis process, and is involved in the generation of cancer stem cells (CSCs). However, its involvement in gastric carcinogenesis has yet not been studied. Therefore, the aim of this study was to determine the role of H. pylori in EMT and in the emergence of gastric CSCs. For this purpose, gastric epithelial cells were cocultured with a cagA-positive H. pylori strain or its isogenic-deleted mutants or were transfected with CagA expression vectors. Study of the expression of epithelial and mesenchymal markers showed that H. pylori, via CagA, is responsible for an EMT phenotype associated with an increase in mesenchymal markers as well as CD44 expression, a known gastric CSC marker. Moreover, infection led to an increased ability to migrate, to invade and to form tumorspheres. Cell sorting experiments showed that only the CD44(high) cells induced by H. pylori infection displayed the mesenchymal phenotype and CSC properties in vitro, and had higher tumorigenic properties than CD44(low) cells in xenografted mice. Immunohistochemistry analyses on human and mouse gastric mucosa tissue samples confirmed a high expression of CD44 and mesenchymal markers in H. pylori-infected cases, and in gastric dysplasia and carcinoma. All of these data suggest that H. pylori, via CagA, unveils CSC-like properties by induction of EMT-like changes in gastric epithelial cells.

Eph receptor B4 is a regulator of estrogen receptor alpha in breast cancer cells

BACKGROUND

Estrogen receptor alpha (ER-α) plays an important role in breast cancer initiation and progression and represents a major target in cancer therapy. The expression and activity of ER-α is regulated by multiple mechanisms at the transcriptional and post-translational level. Interaction of tyrosine kinase receptor-activated signaling pathways with ER-α function has been reported. We previously performed a kinome-wide small interfering RNA high-throughput screen to identify novel protein kinases involved in the regulation of ER-α transcriptional activity in human breast cancer cells. Our screening analysis identified the Eph receptor tyrosine kinases (Eph) as potential positive regulators of ER-α.

RESULTS

In this study, we demonstrate Eph receptor B4 (EphB4), a member of Eph kinase family, a positive regulator of ER-α in human breast cancer cell lines (MCF-7, T-47D and BT-474). Down-regulation of EphB4 by RNA interference technology impairs estrogen-dependent ER-α transcriptional activity in breast cancer cells. Decreased activity of ER-α after EphB4 knockdown is the consequence of diminished ER-α messenger RNA and protein expression. Furthermore, phosphorylation of Akt, a downstream mediator of EphB4, is reduced following EphB4 silencing.

CONCLUSIONS

Our data suggests EphB4 as an upstream regulator of ER-α in human breast cancer cells by modulating ER-α transcription. The results also suggest Akt as a relevant downstream signaling molecule in this novel EphB4-ER-α pathway.

A User Study on Curved Edges in Graph Visualization

Recently there has been increasing research interest in displaying graphs with curved edges to produce more readable visualizations. While there are several automatic techniques, little has been done to evaluate their effectiveness empirically. In this paper we present two experiments studying the impact of edge curvature on graph readability. The goal is to understand the advantages and disadvantages of using curved edges for common graph tasks compared to straight line segments, which are the conventional choice for showing edges in node-link diagrams. We included several edge variations: straight edges, edges with different curvature levels, and mixed straight and curved edges. During the experiments, participants were asked to complete network tasks including determination of connectivity, shortest path, node degree, and common neighbors. We also asked the participants to provide subjective ratings of the aesthetics of different edge types. The results show significant performance differences between the straight and curved edges and clear distinctions between variations of curved edges.

Adsorption of water vapor by poly(styrenesulfonic acid), sodium salt: isothermal and isobaric adsorption equilibria

Air conditioning and dehumidifying systems based on sorption on solids are of great interest, especially in humid climates, because they allow reduction of thermal loads and use of chlorofluorocarbons. Previous studies have shown that hydrophilic polymers such as sulfonic polymers can have very high performance in water adsorption from air. The aim of this study was to characterize the water vapor adsorption properties of fully sulfonated and monosulfonated poly(styrenesulfonic acid), sodium salt, and to elucidate the mechanism of adsorption on these materials. Adsorption isotherms have been determined by TGA between 298 and 317 K for pressures ranging from 0.1 to 45 hPa. They have type II of the IUPAC classification and a small hysteresis loop between adsorption and desorption processes was observed only for the monosulfonated sample. Water content is up to 80% weight at 80% relative humidity. Adsorption isotherms have been well fitted with the FHH model. Adsorption-desorption isobars have been determined by TGA under 37 hPa in the temperature range 298-373 K. They show that these polymers can be completely regenerated by heating at 313 K under humidified air. No degradation of the adsorption properties has been observed after several regenerations. Adsorption enthalpies and entropies have been deduced from the Clapeyron equation and from DSC measurements. A good agreement was found. A mechanism of adsorption is proposed considering two kinds of adsorbate: bounded water in electrostatic interaction with functional groups and free water resulting from condensation.

Challenges of assuring crew safety in space shuttle missions with international cargoes

The top priority in America's manned space flight program is the assurance of crew and vehicle safety. This priority gained greater focus during and after the Space Shuttle return-to-flight mission (STS-26). One of the interesting challenges has been to assure crew safety and adequate protection of the Space Shuttle, as a national resource, from increasingly diverse cargoes and operations. The control of hazards associated with the deployment of complex payloads and cargoes has involved many international participants. These challenges are examined in some detail along with examples of how crew safety has evolved in the manned space program and how the international partners have addressed various scenarios involving control and mitigation of potential hazards to crew and vehicle safety.

Elevation of internal auditory canal pressure by vestibular schwannomas

OBJECTIVE

The exact mechanism of hearing loss, the most common presenting symptom in patients with vestibular schwannomas, remains unclear. To test whether increased pressure in the internal auditory canal from tumor growth is responsible for this clinical finding, the intracanalicular pressure in patients harboring these tumors was measured.

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral hospital.

PATIENTS

Fifteen consecutive patients undergoing a retrosigmoid approach for resection of vestibular schwannomas were included in the study.

INTERVENTION

The intracanalicular pressure in every patient was measured by introducing a pressure microsensor into the internal auditory canal. The pressure readings, which were performed before tumor resection, were then correlated with tumor size and respective preoperative hearing status.

RESULTS

Placement of the pressure monitor into the internal auditory canal revealed a biphasic waveform in every patient. Whereas the mean intracanalicular pressure was 20 mm Hg, there was significant variability among patients (range, 1-45 mm Hg). The intracanalicular pressure directly correlated with the amount of tumor in the internal auditory canal (r > 0.63, p < 0.012) but not with the total tumor size (r </= 0.40, p > 0.075). Furthermore, eight patients with class A preoperative hearing (American Academy of Otolaryngology-Head and Neck Surgery classification) had lower intracanalicular pressures than did five patients with class B hearing (16 +/- 5 vs. 28 +/- 4). Although this observation suggested an inverse correlation between the intracanalicular pressure and hearing function, the difference between the two groups was not statistically significant (p = 0.14).

CONCLUSION

Pressure on the cochlear nerve as a result of tumor growth in the internal auditory canal may be responsible for hearing loss in patients with vestibular schwannomas. Modification of surgical techniques to address the elevated intracanalicular pressure may be beneficial in improving hearing preservation in these patients.

Influence of muscle fibre type and fitness on the oxygen uptake/power output slope during incremental exercise in humans

We recently reported that a higher percentage of type I fibres in vastus lateralis and a greater peak oxygen uptake (O2) were associated with a greater initial rise in O2 (O2 /W, where W is work rate) following the onset of heavy constant power output exercise (above the lactate threshold, LT). It was unclear if these results were true only for heavy exercise, or if the association between fibre type and/or fitness and O2 /W would also be seen for moderate (< LT) exercise. The purpose of the present study was to compare the relationships between fibre type or peak O2 and O2 /W determined for moderate (< LT) and heavy (> LT) exercise intensities during incremental exercise. Nine healthy subjects performed an incremental ramp test on a cycle ergometer. The O2 /Wslope was calculated for the domain of power outputs up to the LT (S1), from the LT towards peak O2 (S2), and over the entire linear portion of the O2 /W response (ST), and compared to fibre type distribution determined from biopsy of the vastus lateralis, and to peak O2 (as ml kg-1 min-1). Significant correlations between O2 /W and the proportion of type I fibres were found for each exercise domain (r is 0.69, 0.71 and 0.84 for S1, S2 and ST, respectively, P < 0.05). S1 ranged between about 9 ml min-1 W-1 for a low proportion of type I fibres and 11 ml min-1 W-1 for a high proportion of type I fibres. Similar correlations were also found between S2 (r = 0.70) and ST (r = 0.76) and peak O2. These results are consistent with our previous findings during > LT constant power output exercise, and suggest that the proportion of type I fibres, and possibly fitness as indicated by peak O2, is associated with greater O2 /W during the initial adjustment to < LT as well as > LT exercise. These results do not appear to be explained by classical descriptions of the kinetics of adjustment of O2 following the onset of ramp or constant power output exercise. They might reflect enhanced motor unit recruitment in subjects with a greater percentage of type I fibres, and/or who are more aerobically fit. However, the underlying mechanism for these findings must await further study.

A role for Groucho tetramerization in transcriptional repression

The Drosophila Groucho (Gro) protein is a corepressor required by a number of DNA-binding transcriptional repressors. Comparison of Gro with its homologues in other eukaryotic organisms reveals that Gro contains, in addition to a conserved C-terminal WD repeat domain, a conserved N-terminal domain, which has previously been implicated in transcriptional repression. We determined, via a variety of hydrodynamic measurements as well as protein cross-linking, that native Gro is a tetramer in solution and that tetramerization is mediated by two putative amphipathic alpha-helices (termed leucine zipper-like motifs) found in the N-terminal region. Point mutations in the leucine zipper-like motifs that block tetramerization also block repression by Gro, as assayed in cultured Drosophila cells with Gal4-Gro fusion proteins. Furthermore, the heterologous tetramerization domain from p53 fully substitutes for the Gro tetramerization domain in transcriptional repression. These findings suggest that oligomerization is essential for Gro-mediated repression and that the primary function of the conserved N-terminal domain is to mediate this oligomerization.

Expression of the apoptosis-related genes, caspase-1, caspase-3, DNA fragmentation factor, and apoptotic protease activating factor-1, in human granulosa cells

OBJECTIVE

To investigate protein and messenger RNA expression products for a subset of apoptosis-related genes in human granulosa cells.

DESIGN

In vitro experiment.

SETTING

Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.

PATIENT(S)

Women undergoing oocyte retrieval for IVF after ovulation induction with gonadotropins.

INTERVENTION(S)

Granulosa cells were isolated from follicular aspirates after oocyte removal.

MAIN OUTCOME MEASURE(S)

Reverse transcription polymerase chain reaction and Western blotting for apoptosis-related gene products.

RESULT(S)

The expression of caspase-1, caspase-3, DNA fragmentation factor, and apoptotic protease activating factor-1, which are intermediate molecules in phylogenetically conserved apoptotic pathways, was demonstrated in granulosa cells from patients undergoing IVF. Moreover, proforms, but not activated enzymes, for both caspase-1 and caspase-3 were observed.

CONCLUSION(S)

Granulosa cells from patients undergoing IVF have intrinsic apoptotic machinery that could be activated for tissue remodeling.

Modulation of Igf2 genomic imprinting in mice induced by 5-azacytidine, an inhibitor of DNA methylation

The adjacent genes, insulin-like growth factor 2 (Igf2) and H19, are imprinted in both mouse and human. While Igf2 is expressed from the paternal allele, H19 is transcribed exclusively from the maternal allele. To explore the underlying mechanism of Igf2 and H19 imprinting, we studied the effect of DNA demethylation on allelic expression by injecting mice with the demethylating agent 5-azacytidine (5-aza-C). We observed a > or = 2-fold increase in the abundance of Igf2 mRNA in liver from treated mice compared with that of control mice. There was no significant change in Igf2 or H19 expression in brain. In the 5-aza-C-treated mice, there was dramatic modulation of Igf2 imprinting. In some tissues, Igf2 was expressed biallelically, while in other tissues, the paternal allele was silenced and the normally imprinted maternal allele was expressed, an example of allelic switching. There was no change in the normal biallelic pattern of Igf2 expression in brain. H19, on the other hand, remained imprinted in all tissues in mice treated with 5-aza-C. These results provide the first example of a pharmacological manipulation of genomic imprinting of an endogenous gene in vivo and further implicate DNA methylation as an important factor in maintaining the differential allelic expression of the Igf2 gene.

Modulation of Igf2 genomic imprinting in mice induced by 5-azacytidine, an inhibitor of DNA methylation

The adjacent genes, insulin-like growth factor 2 (Igf2) and H19, are imprinted in both mouse and human. While Igf2 is expressed from the paternal allele, H19 is transcribed exclusively from the maternal allele. To explore the underlying mechanism of Igf2 and H19 imprinting, we studied the effect of DNA demethylation on allelic expression by injecting mice with the demethylating agent 5-azacytidine (5-aza-C). We observed a > or = 2-fold increase in the abundance of Igf2 mRNA in liver from treated mice compared with that of control mice. There was no significant change in Igf2 or H19 expression in brain. In the 5-aza-C-treated mice, there was dramatic modulation of Igf2 imprinting. In some tissues, Igf2 was expressed biallelically, while in other tissues, the paternal allele was silenced and the normally imprinted maternal allele was expressed, an example of allelic switching. There was no change in the normal biallelic pattern of Igf2 expression in brain. H19, on the other hand, remained imprinted in all tissues in mice treated with 5-aza-C. These results provide the first example of a pharmacological manipulation of genomic imprinting of an endogenous gene in vivo and further implicate DNA methylation as an important factor in maintaining the differential allelic expression of the Igf2 gene.

Nitric oxide production during exercise in chronic heart failure

In chronic heart failure (CHF), the ventilatory response is increased compared with normal. This response is, in part, caused by reduced perfusion to ventilated lung. Nitric oxide (NO) is a potent vasodilator and may have an important role in pulmonary vasodilatation during exercise. NO is present in exhaled air. The amount of NO in exhaled air, when breathing NO-free compressed air, is known to increase in normal subjects during exercise. In this study, we quantified NO output in exhaled air in patients with CHF during exercise. Six patients with CHF (New York Heart Association Class II and III; two with dilated cardiomyopathy, three with ischemic heart disease, and one with hypertensive heart disease) and six normal subjects were studied with a symptom-limited incremental exercise test on a cycle ergometer. Oxygen uptake (VO2), carbon dioxide output (VCO2), and minute ventilation (VE) were measured breath by breath with a mass spectrometer, flow meter, and computer. The NO concentration was continuously measured in mixed expired air by chemiluminescence. Peak exercise work rate was lower in patients with CHF than in normal subjects (71.3 +/- 41.6 W vs 257.0 +/- 49.7 W; p < 0.01). Patients with CHF showed a higher VE/VCO2 level at peak exercise than normal subjects (CHF, 47.0 +/- 10.7; normal subjects, 35.6 +/- 5.2; p < 0.01). NO concentration of exhaled air at rest was lower in CHF patients than in normal subjects (4.0 +/- 2.2 ppb vs 10.5 +/- 6.2 ppb, respectively; p < 0.05). NO output from the respiratory tract (VNO) was significantly lower in patients with CHF compared with normal subjects at rest (45.3 +/- 24.3 nl/min, 117.5 +/- 60.1 nl/min, respectively, p < 0.05), and although it increased during exercise, it did not increase in patients with CHF as much as in normal subjects (75.3 +/- 43.4 nl/min vs 512.9 +/- 253.6 nl/min, respectively; p < 0.01). The increase above rest (exercise/rest) was smaller in patients with CHF than in normal subjects (2.10 +/- 1.92 vs 4.81 +/- 2.67, p < 0.05). These data support the concept that the smaller increase in NO production (VNO) during exercise may be responsible for a blunted vasodilation in patients with CHF, resulting in a smaller reduction in dead space/tidal volume and VE/VCO2 at the lactic acidosis threshold than normal. This finding may play a role in the abnormally high ventilatory response to exercise in patients with CHF.

CADIAG-2 and MYCIN-like systems

CADIAG-2 and MYCIN-like systems are expert systems with numerous applications in medicine. CADIAG-2 is a fuzzy expert system based on max-min inference, while MYCIN-like systems use combining functions to calculate the global weights (degrees) of suggested diagnoses. This paper brings a comparison of CADIAG-2 and MYCIN-like systems. It studies relations between them and shows how CADIAG-2 can be embedded into MYCIN-like systems. An approach of inclusion of negative knowledge into CADIAG-2 is proposed. Some remarks regarding the acquisition of weights of rules are given as well.

Influence of muscle fiber type and pedal frequency on oxygen uptake kinetics of heavy exercise

We tested the hypothesis that the amplitude of the additional slow component of O2 uptake (VO2) during heavy exercise is correlated with the percentage of type II (fast-twitch) fibers in the contracting muscles. Ten subjects performed transitions to a work rate calculated to require a VO2 equal to 50% between the estimated lactate (Lac) threshold and maximal VO2 (50% delta). Nine subjects consented to a muscle biopsy of the vastus lateralis. To enhance the influence of differences in fiber type among subjects, transitions were made while subjects were pedaling at 45, 60, 75, and 90 rpm in different trials. Baseline VO2 was designed to be similar at the different pedal rates by adjusting baseline work rate while the absolute increase in work rate above the baseline was the same. The VO2 response after the onset of exercise was described by a three-exponential model. The relative magnitude of the slow component at the end of 8-min exercise was significantly negatively correlated with % type I fibers at every pedal rate (r = 0.64 to 0.83, P < 0.05-0.01). Furthermore, the gain of the fast component for VO2 (as ml.min-1.W-1) was positively correlated with the % type I fibers across pedal rates (r = 0.69-0.83). Increase in pedal rate was associated with decreased relative stress of the exercise but did not affect the relationships between % fiber type and VO2 parameters. The relative contribution of the slow component was also significantly negatively correlated with maximal VO2 (r = -0.65), whereas the gain for the fast component was positively associated (r = 0.68-0.71 across rpm). The amplitude of the slow component was significantly correlated with net end-exercise Lac at all four pedal rates (r = 0.64-0.84), but Lac was not correlated with % type I (P > 0.05). We conclude that fiber type distribution significantly affects both the fast and slow components of VO2 during heavy exercise and that fiber type and fitness may have both codependent and independent influences on the metabolic and gas-exchange responses to heavy exercise.

Effects of cocaine and corticotropin-releasing factor on pulsatile ACTH and cortisol release in ovariectomized rhesus monkeys

Cocaine stimulates ACTH secretion by a corticotropin-releasing factor (CRF)-dependent mechanism in male rats, rhesus monkeys, and humans. To determine the generality of this effect, we examined the effects of acute cocaine administration on the pulsatile release of ACTH and cortisol in three ovariectomized (OVX) rhesus monkeys and compared its effects to stimulation with CRF. Venous blood samples were collected at 2-min intervals for 60 min before and after iv administration of cocaine (0.4 and 0.8 mg/kg) and CRF (1.0 and 10 micrograms/kg). Cluster analysis procedures were used to evaluate the pulsatile characteristics of ACTH and cortisol release. After placebo administration, an ACTH pulse frequency of 3 peaks/h was detected. After cocaine administration, plasma cocaine levels peaked at 92 +/- 3.0 and 201 +/- 60 ng/mL within 2 min. However, in contrast to normal intact males, cocaine did not stimulate the pulsatile release of ACTH in OVX females. Cocaine (0.4 mg/kg) decreased ACTH incremental peak height and valley levels compared with pre-cocaine values, and a higher dose of cocaine produced no changes in ACTH release. Bolus injection of a low dose of CRF (1.0 micrograms/kg, iv) significantly increased ACTH incremental peak height (P < 0.05), and a higher dose of CRF (10 micrograms/kg) increased ACTH peak amplitude, percentage increase in peak amplitude, area under the peaks, and incremental peak heights as well as ACTH valley level and nadir (10 micrograms/kg, iv) (P < 0.05). ACTH pulse frequency did not change after CRF or cocaine administration. Pulsatile release of cortisol was 2.7 peaks/h under placebo conditions and did not change after cocaine or CRF administration. Cortisol pulse amplitude was increased after low and high doses of CRF. High doses of CRF (10 micrograms/kg) also increased the mean level of cortisol valleys. In summary, we found that CRF but not cocaine stimulated pulsatile ACTH and cortisol release in OVX rhesus monkeys. The profound ACTH response to CRF challenge suggests that the CRF sensitivity and the ACTH release capacity of the anterior pituitary corticotroph cells were intact. The lack of stimulatory effects of cocaine on the hypothalamic-pituitary-adrenal axis in OVX monkeys, in contrast to normal male monkeys, may reflect the absence of gonadal steroids.

Protective effect of a 21-aminosteroid against hemorrhage-induced ischemia-reperfusion injury in the rat stomach: role of lipid peroxidation

We investigated the role that lipid peroxidation plays in a hemorrhage-induced ischemia-reperfusion model of gastric injury. Rats were pretreated with an inhibitor of this process, a 21-aminosteroid (U-74389G, 10 mg/kg), or an appropriate control solution intravenously 15 min prior to 20 min of ischemia, followed by 20 min of reperfusion. Results indicated that U-74389G pretreatment significantly attenuated gastric damage compared with corresponding control animals (19.8 vs. 176.8 mm2, p < .001). Enaldehyde levels (picomoles/mg protein), a biochemical index of lipid peroxidation, paralleled these injury findings (12 vs 960, p < .001). Histologically, U-74389G pretreatment almost completely prevented gastric injury compared to control stomachs. Additional studies revealed that lipid peroxidation preceded the formation of gastric damage, and injury occurred predominantly during reperfusion, because animals subjected to ischemia alone without reperfusion failed to develop appreciable injury or enhanced enaldehyde formation. Further, if U-74389G was given intravenously after ischemia, but prior to reperfusion, gastric injury and enaldehyde formation were similarly attenuated. Our findings are consistent with the hypothesis that lipid peroxidation likely plays an important role in hemorrhage-induced ischemia-reperfusion injury to the stomach.

Intraleucocytic malaria pigment and prognosis in severe malaria

The quantity of malaria pigment liberated into the circulation at schizogony reflects the pathogenic sequestered parasite burden in Plasmodium falciparum malaria, and may therefore be a measure of disease severity. Among 300 consecutive adult patients with severe falciparum malaria, the 40 who died had significantly higher proportions of malaria pigment-containing neutrophils on admission (mean = 7.7%, standard deviation (SD) = 5.9%) and pigment-containing monocytes (mean = 8.6%, SD = 5.9%) than did survivors (mean 3.2%, SD = 4.1% and mean 4.8%, SD = 4.6%, respectively) (P < 0.0001). This proved a better indicator of prognosis than the peripheral parasite count. A count of peripheral neutrophils containing visible pigment > or = 5% predicted a fatal outcome with 73% sensitivity and 77% specificity (relative risk 6.2, 95% confidence interval (CI) 3.2-11.8) compared to 60% sensitivity and 57% specificity for parasitaemia > 100,000/microL (relative risk 1.8, 95% CI 1.0-3.3). The peripheral blood count of pigment-containing neutrophils in severe malaria is a rapid, simple, and practical prognostic test.