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The G protein-coupled receptor proteinase-activated receptor 2 (PAR2) has been implicated
in various aspects of cellular physiology including inflammation, obesity and cancer. In cancer,
it usually acts as a driver of cancer progression in various tumor types by promoting invasion and
metastasis in response to activation by serine proteinases. Recently, we discovered another mode
through which PAR2 may enhance tumorigenesis: crosstalk with transforming growth factor-β
(TGF-β) signaling to promote TGF-β1-induced cell migration/invasion and invasion-associated gene
expression in ductal pancreatic adenocarcinoma (PDAC) cells. In this chapter, we review what is
known about the cellular TGF-β responses and signaling pathways affected by PAR2 expression,
the signaling activities of PAR2 required for promoting TGF-β signaling, and the potential molecular
mechanism(s) that underlie(s) the TGF-β signaling–promoting effect. Since PAR2 is activated through
various serine proteinases and biased agonists, it may couple TGF-β signaling to a diverse range of
other physiological processes that may or may not predispose cells to cancer development such as
local inflammation, systemic coagulation and pathogen infection.
Leukocyte telomere length (TL) has been suggested as a marker of biological age in healthy
individuals, but can also reflect inherited and acquired hematopoietic dysfunctions or indicate an
increased turnover of the hematopoietic stem and progenitor cell compartment. In addition, TL is able
to predict the response rate of tyrosine kinase inhibitor therapy in chronic myeloid leukemia (CML),
indicates clinical outcomes in chronic lymphocytic leukemia (CLL), and can be used as screening tool
for genetic sequencing of selected genes in patients with inherited bone marrow failure syndromes
(BMFS). In tumor cells and clonal hematopoietic disorders, telomeres are continuously stabilized by
reactivation of telomerase, which can selectively be targeted by telomerase-specific therapy. The use of
the telomerase inhibitor Imetelstat in patients with essential thrombocythmia or myelofibrosis as well
as the use of dendritic cell-based telomerase vaccination in AML patients with complete remissions are
promising examples for anti-telomerase targeted strategies in hematologic malignancies. In contrast,
the elevation in telomerase levels through treatment with androgens has become an exciting clinical
intervention for patients with BMFS. Here, we review recent developments, which highlight the
impact of telomeres and telomerase targeted therapies in hematologic dysfunctions.
: Human osteosarcoma (OS) is the most common primary malignant bone tumor occurring
most commonly in adolescents and young adults. Major improvements in disease-free survival have
been achieved by implementing a combination therapy consisting of radical surgical resection of the
tumor and systemic multi-agent chemotherapy. However, long-term survival remains poor, so novel
targeted therapies to improve outcomes for patients with osteosarcoma remains an area of active
research. This includes immunotherapy, photodynamic therapy, or treatment with nanoparticles.
Cold atmospheric plasma (CAP), a highly reactive (partially) ionized physical state, has been shown
to inherit a significant anticancer capacity, leading to a new field in medicine called “plasma oncology.”
The current article summarizes the potential of CAP in the treatment of human OS and reviews the
underlying molecular mode of action.
Multiple evidence in animal models and in humans suggest a beneficial role of cold physical
plasma in wound treatment. Yet, risk assessment studies are important to further foster therapeutic
advancement and acceptance of cold plasma in clinics. Accordingly, we investigated the long-term
side effects of repetitive plasma treatment over 14 consecutive days in a rodent full-thickness ear
wound model. Subsequently, animals were housed for 350 days and sacrificed thereafter. In blood,
systemic changes of the pro-inflammatory cytokines interleukin 1β and tumor necrosis factor α
were absent. Similarly, tumor marker levels of α-fetoprotein and calcitonin remained unchanged.
Using quantitative PCR, the expression levels of several cytokines and tumor markers in liver,
lung, and skin were found to be similar in the control and treatment group as well. Likewise,
histological and immunohistochemical analysis failed to detect abnormal morphological changes
and the presence of tumor markers such as carcinoembryonic antigen, α-fetoprotein, or the neighbor
of Punc 11. Absence of neoplastic lesions was confirmed by non-invasive imaging methods such as
anatomical magnetic resonance imaging and positron emission tomography-computed tomography.
Our results suggest that the beneficial effects of cold plasma in wound healing come without apparent
side effects including tumor formation or chronic inflammation.
Background: Recently, the expression of proteinase-activated receptor 2 (PAR2) has been
shown to be essential for activin receptor-like kinase 5 (ALK5)/SMAD-mediated signaling and cell
migration by transforming growth factor (TGF)-β1. However, it is not known whether activation
of non-SMAD TGF-β signaling (e.g., RAS–RAF–MEK–extracellular signal-regulated kinase (ERK)
signaling) is required for cell migration and whether it is also dependent on PAR2. Methods: RNA
interference was used to deplete cells of PAR2, followed by xCELLigence technology to measure
cell migration, phospho-immunoblotting to assess ERK1/2 activation, and co-immunoprecipitation
to detect a PAR2–ALK5 physical interaction. Results: Inhibition of ERK signaling with the MEK
inhibitor U0126 blunted the ability of TGF-β1 to induce migration in pancreatic cancer Panc1 cells.
ERK activation in response to PAR2 agonistic peptide (PAR2–AP) was strong and rapid, while it was
moderate and delayed in response to TGF-β1. Basal and TGF-β1-dependent ERK, but not SMAD
activation, was blocked by U0126 in Panc1 and other cell types indicating that ERK activation is
downstream or independent of SMAD signaling. Moreover, cellular depletion of PAR2 in HaCaT
cells strongly inhibited TGF-β1-induced ERK activation, while the biased PAR2 agonist GB88 at 10
and 100 µM potentiated TGF-β1-dependent ERK activation and cell migration. Finally, we provide
evidence for a physical interaction between PAR2 and ALK5. Our data show that both PAR2–APand TGF-β1-induced cell migration depend on ERK activation, that PAR2 expression is crucial for
TGF-β1-induced ERK activation, and that the functional cooperation of PAR2 and TGF-β1 involves a
physical interaction between PAR2 and ALK5
The multifunctional sphingosine-1-phosphate (S1P) is a lipid signaling molecule and central
regulator in the development of several cancer types. In recent years, intriguing information has
become available regarding the role of S1P in the progression of Glioblastoma multiforme (GBM),
the most aggressive and common brain tumor in adults. S1P modulates numerous cellular processes
in GBM, such as oncogenesis, proliferation and survival, invasion, migration, metastasis and stem cell
behavior. These processes are regulated via a family of five G-protein-coupled S1P receptors (S1PR1-5)
and may involve mainly unknown intracellular targets. Distinct expression patterns and multiple
intracellular signaling pathways of each S1PR subtype enable S1P to exert its pleiotropic cellular
actions. Several studies have demonstrated alterations in S1P levels, the involvement of S1PRs
and S1P metabolizing enzymes in GBM pathophysiology. While the tumorigenic actions of S1P
involve the activation of several kinases and transcription factors, the specific G-protein (Gi, Gq,
and G12/13)-coupled signaling pathways and downstream mediated effects in GBM remain to be
elucidated in detail. This review summarizes the recent findings concerning the role of S1P and its
receptors in GBM. We further highlight the current insights into the signaling pathways considered
fundamental for regulating the cellular processes in GMB and ultimately patient prognosis.
Abstract
Alkali ion beams are among the most intense produced by the ISOLDE facility. These were the first to be studied by the ISOLTRAP mass spectrometer and ever since, new measurements have been regularly reported. Recently the masses of very neutron-rich and short-lived cesium isotopes were determined at ISOLTRAP. The isotope 148Cs was measured directly for the first time by Penning-trap mass spectrometry. Using the new results, the trend of two-neutron separation energies in the cesium isotopic chain is revealed to be smooth and gradually decreasing, similar to the ones of the barium and xenon isotopic chains. Predictions of selected microscopic models are employed for a discussion of the experimental data in the region.
Abstract
The presented work highlights the role of residual weakly-bound surface electrons acting as an effective seed electron reservoir that favors the pre-ionization of diffuse barrier discharges (BDs). A glow-like BD was operated in helium at a pressure of 500 mbar in between two plane electrodes each covered with float glass at a distance of
3 mm.The change in discharge development due to laser photodesorption of surface electrons was studied by electrical measurements and optical emission spectroscopy. Moreover, a 1D numerical fluid model of the diffuse discharge allowed the simulation of the laser photodesorption experiment, the estimation of the released surface electrons, and the understanding of their impact on the reaction kinetics in the volume. The breakdown voltage is clearly reduced when the laser beam at photon energy of 2.33 eV hits the cathodic dielectric that is charged with residual electrons during the discharge pre-phase. According to the adapted simulation, the laser releases only a small amount of surface electrons in the order of
10 pC. Nevertheless, this significantly supports the pre-ionization. Using a lower photon energy of 1.17 eV, the transition from the glow mode to the Townsend mode is induced due to a much higher electron yield up to 1 nC. In this case, both experiment and simulation indicate a retarded stepwise release of surface electrons initiated by the low laser photon energy.
Abstract
In this series of two papers we present results about the E-H transition of an inductively coupled oxygen discharge driven at radio frequency (13.56 MHz) for different total gas pressures. The mode transition from the low density E-mode to the high density H-mode is studied using comprehensive plasma diagnostics. The measured electron density can be used to distinguish between the different operation modes. This paper focuses on the determination of the negative atomic ion density and the electronegativity by two experimental methods and global rate equation calculation. As a result, the electronegativity significantly decreases over two orders of magnitude from about 25 in the E-mode to about 0.1 in the H-mode. The temporal behavior of the electronegativity in pulsed ICP shows that the negative atomic ion density reaches a steady state after 10 ms. Negative atomic ions are mainly produced by the dissociative attachment with the molecular ground state. The ion–ion recombination with the positive molecular ions and the collisional detachment with the singlet molecular metastables contribute significantly to the loss of the negative atomic ions.
Abstract
In this series of two papers, the E-H transition in a planar inductively coupled radio frequency discharge (13.56 MHz) in pure oxygen is studied using comprehensive plasma diagnostic methods. The electron density serves as the main plasma parameter to distinguish between the operation modes. The (effective) electron temperature, which is calculated from the electron energy distribution function and the difference between the floating and plasma potential, halves during the E-H transition. Furthermore, the pressure dependency of the RF sheath extension in the E-mode implies a collisional RF sheath for the considered total gas pressures. The gas temperature increases with the electron density during the E-H transition and doubles in the H-mode compared to the E-mode, whereas the molecular ground state density halves at the given total gas pressure. Moreover, the singlet molecular metastable density reaches 2% in the E-mode and 4% in the H-mode of the molecular ground state density. These measured plasma parameters can be used as input parameters for global rate equation calculations to analyze several elementary processes. Here, the ionization rate for the molecular oxygen ions is exemplarily determined and reveals, together with the optical excitation rate patterns, a change in electronegativity during the mode transition.