209 research outputs found
Extracellular Matrix Protein Tenascin C Increases Phagocytosis Mediated by CD47 Loss of Function in Glioblastoma.
Glioblastomas (GBM) are highly infiltrated by myeloid-derived innate immune cells that contribute to the immunosuppressive nature of the brain tumor microenvironment (TME). CD47 has been shown to mediate immune evasion, as the CD47-SIRPα axis prevents phagocytosis of tumor cells by macrophages and other myeloid cells. In this study, we established CD47 homozygous deletion (CD47-/-) in human and mouse GBM cells and investigated the impact of eliminating the "don't eat me" signal on tumor growth and tumor-TME interactions. CD47 knockout (KO) did not significantly alter tumor cell proliferation in vitro but significantly increased phagocytosis of tumor cells by macrophages in cocultures. Compared with CD47 wild-type xenografts, orthotopic xenografts derived from CD47-/- tumor cells grew significantly slower with enhanced tumor cell phagocytosis and increased recruitment of M2-like tumor-associated microglia/macrophages (TAM). CD47 KO increased tumor-associated extracellular matrix protein tenascin C (TNC) in xenografts, which was further examined in vitro. CD47 loss of function upregulated TNC expression in tumor cells via a Notch pathway-mediated mechanism. Depletion of TNC in tumor cells enhanced the growth of CD47-/- xenografts in vivo and decreased the number of TAM. TNC knockdown also inhibited phagocytosis of CD47-/- tumor cells in cocultures. Furthermore, TNC stimulated release of proinflammatory factors including TNFα via a Toll-like receptor 4 and STAT3-dependent mechanism in human macrophage cells. These results reveal a vital role for TNC in immunomodulation in brain tumor biology and demonstrate the prominence of the TME extracellular matrix in affecting the antitumor function of brain innate immune cells. SIGNIFICANCE: These findings link TNC to CD47-driven phagocytosis and demonstrate that TNC affects the antitumor function of brain TAM, facilitating the development of novel innate immune system-based therapies for brain tumors
Ex-vivo Fluorescence Confocal Microscopy: The First Application For Real-Time Pathologic Examination of Prostatic Tissue
Prostate cancer "real time" intra-operative pathological examination currently utilizes frozen section, despite the many inherent limitations of this procedure. Ex vivo Fluorescence Confocal Microscopy (FCM) is a novel technology, which provides fast microscopic fluorescence and reflectance tissue imaging. FCM has been proven beneficial in colorectal, breast, thyroid and skin lesions. However, it was never applied in urology. The aim of our study is to report the first application of FCM in the urologic field assessing its diagnostic accuracy for non-neoplastic and cancerous prostate tissue (prostatic adenocarcinoma) compared to the gold standard histopathological diagnoses.Objective: To report the first application of ex vivo fluorescence confocal microscopy (FCM) - a novel optical technology that is capable of providing fast microscopic imaging of unfixed tissue specimens- in the urological field assessing its diagnostic accuracy for non neoplastic and cancerous prostate tissue (prostatic adenocarcinoma) compared to the 'gold standard' histopathological diagnoses. Patients and methods: In all, 89 specimens from 13 patients with clinically localised prostate cancer were enrolled into the study. All patients underwent robot-assisted laparoscopic radical prostatectomy with fresh prostatic tissue biopsies taken at the end of each intervention using an 18-G biopsy punch. Specimens were randomly assigned to the three collaborating pathologists for evaluation. Intra- and inter-observer agreement was tested by the means of Cohen's κ. The diagnostic performance was evaluated on receiver operating characteristic curve analysis. Results: The overall diagnostic agreement between FCM and histopathological diagnoses was substantial with a 91% correct diagnosis (κ = 0.75) and an area under the curve of 0.884 (95% confidence interval 0.840–0.920), 83.33% sensitivity, and 93.53% specificity. Conclusion: FCM seems to be a promising tool for enhanced specimens' reporting performance, given its simple application and very rapid microscopic image generation (<5 min/specimen). This technique may potentially be used for intraoperative pathological specimens' analysis
Entanglement and the Kondo effect in double quantum dots
We investigate entanglement between electrons in serially coupled double
quantum dots attached to non interacting leads. In addition to local repulsion
we consider the influence of capacitive inter-dot interaction. We show how the
competition between extended Kondo and local singlet phases determines the
ground state and thereby the entanglement.Comment: EPJ Special Topics 200
Life expectancy of young adults with follicular lymphoma
FL patients younger than 40 have a median OS of 24 years and their outcome improved over time. However, they still have a significantly shorter life expectancy when compared with that of an age-matched general healthy population. FL in young adults, differently from paediatric FL, does not seem to represent a distinct entit
Targeting RNA transcription and translation in ovarian cancer cells with pharmacological inhibitor CDKI-73
Dysregulation of cellular transcription and translation is a fundamental hallmark
of cancer. As CDK9 and Mnks play pivotal roles in the regulation of RNA transcription
and protein synthesis, respectively, they are important targets for drug development.
We herein report the cellular mechanism of a novel CDK9 inhibitor CDKI-73 in an
ovarian cancer cell line (A2780). We also used shRNA-mediated CDK9 knockdown
to investigate the importance of CDK9 in the maintenance of A2780 cells. This study
revealed that CDKI-73 rapidly inhibited cellular CDK9 kinase activity and downregulated
the RNAPII phosphorylation. This subsequently caused a decrease in the
eIF4E phosphorylation by blocking Mnk1 kinase activity. Consistently, CDK9 shRNA
was also found to down-regulate the Mnk1 expression. Both CDKI-73 and CDK9 shRNA
decreased anti-apoptotic proteins Mcl-1 and Bcl-2 and induced apoptosis. The study
confirmed that CDK9 is required for cell survival and that ovarian cancer may be
susceptible to CDK9 inhibition strategy. The data also implied a role of CDK9 in eIF4Emediated
translational control, suggesting that CDK9 may have important implication
in the Mnk-eIF4E axis, the key determinants of PI3K/Akt/mTOR- and Ras/Raf/MAPKmediated
tumorigenic activity. As such, CDK9 inhibitor drug candidate CDKI-73 should
have a major impact on these pathways in human cancers
Quantum Integrals of Motion for Variable Quadratic Hamiltonians
We construct the integrals of motion for several models of the quantum damped
oscillators in nonrelativistic quantum mechanics in a framework of a general
approach to the time-dependent Schroedinger equation with variable quadratic
Hamiltonians. An extension of Lewis-Riesenfeld dynamical invariant is given.
The time-evolution of the expectation values of the energy related positive
operators is determined for the oscillators under consideration. A proof of
uniqueness of the corresponding Cauchy initial value problem is discussed as an
application.Comment: 32 pages, no figure
Nine-Year Effects of 3.7 Years of Intensive Glycemic Control on Cardiovascular Outcomes
In the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, ∼4 years of intensive versus standard glycemic control in participants with type 2 diabetes and other cardiovascular risk factors had a neutral effect on the composite cardiovascular outcome, increased cardiovascular and total mortality, and reduced nonfatal myocardial infarction. Effects of the intervention during prolonged follow-up were analyzed
Diabetic cardiomyopathy
Diabetic cardiomyopathy is a distinct primary disease process, independent of coronary artery disease, which leads to heart failure in diabetic patients. Epidemiological and clinical trial data have confirmed the greater incidence and prevalence of heart failure in diabetes. Novel echocardiographic and MR (magnetic resonance) techniques have enabled a more accurate means of phenotyping diabetic cardiomyopathy. Experimental models of diabetes have provided a range of novel molecular targets for this condition, but none have been substantiated in humans. Similarly, although ultrastructural pathology of the microvessels and cardiomyocytes is well described in animal models, studies in humans are small and limited to light microscopy. With regard to treatment, recent data with thiazoledinediones has generated much controversy in terms of the cardiac safety of both these and other drugs currently in use and under development. Clinical trials are urgently required to establish the efficacy of currently available agents for heart failure, as well as novel therapies in patients specifically with diabetic cardiomyopathy
Pivotal Role of Inosine Triphosphate Pyrophosphatase in Maintaining Genome Stability and the Prevention of Apoptosis in Human Cells
Pure nucleotide precursor pools are a prerequisite for high-fidelity DNA replication and the suppression of mutagenesis and carcinogenesis. ITPases are nucleoside triphosphate pyrophosphatases that clean the precursor pools of the non-canonical triphosphates of inosine and xanthine. The precise role of the human ITPase, encoded by the ITPA gene, is not clearly defined. ITPA is clinically important because a widespread polymorphism, 94C>A, leads to null ITPase activity in erythrocytes and is associated with an adverse reaction to thiopurine drugs. We studied the cellular function of ITPA in HeLa cells using the purine analog 6-N hydroxylaminopurine (HAP), whose triphosphate is also a substrate for ITPA. In this study, we demonstrate that ITPA knockdown sensitizes HeLa cells to HAP-induced DNA breaks and apoptosis. The HAP-induced DNA damage and cytotoxicity observed in ITPA knockdown cells are rescued by an overexpression of the yeast ITPase encoded by the HAM1 gene. We further show that ITPA knockdown results in elevated mutagenesis in response to HAP treatment. Our studies reveal the significance of ITPA in preventing base analog-induced apoptosis, DNA damage and mutagenesis in human cells. This implies that individuals with defective ITPase are predisposed to genome damage by impurities in nucleotide pools, which is drastically augmented by therapy with purine analogs. They are also at an elevated risk for degenerative diseases and cancer
Does board independence influence financial performance in IPO firms? The moderating role of the national business system
Prior evidence suggests that board independence may enhance financial performance, but this relationship has been tested almost exclusively for Anglo-American countries. To explore the boundary conditions of this prominent governance mechanism, we examine the impact of the formal and information institutions of 18 national business systems on the board independence-financial performance relationship. Our results show that while the direct effect of independence is weak, national-level institutions significantly moderate the independence-performance relationship. Our findings suggest that the efficacy of board structures is likely to be contingent on the specific national context, but the type of legal system is insignificant
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