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Cells Correlates (cell + correlate)
Selected AbstractsWhen is high-Ca2+ microdomain required for mitochondrial Ca2+ uptake?,ACTA PHYSIOLOGICA, Issue 1 2009A. Spät Abstract Ca2+ release from IP3 -sensitive stores in the endoplasmic reticulum (ER) induced by Ca2+ -mobilizing agonists generates high-Ca2+ microdomains between ER vesicles and neighbouring mitochondria. Here we present a model that describes when such microdomains are required and when submicromolar [Ca2+] is sufficient for mitochondrial Ca2+ uptake. Mitochondrial Ca2+ uptake rate in angiotensin II-stimulated H295R adrenocortical cells correlates with the proximity between ER vesicles and the mitochondrion, reflecting the uptake promoting effect of high-Ca2+ peri-mitochondrial microdomains. Silencing or inhibition of p38 mitogen-activated protein kinase (MAPK) or inhibition of the novel isoforms of protein kinase C enhances mitochondrial Ca2+ uptake and abolishes the positive correlation between Ca2+ uptake and ER-mitochondrion proximity. Inhibition of protein phosphatases attenuates mitochondrial Ca2+ uptake and also abolishes its positive correlation with ER-mitochondrion proximity. We postulate that during IP3 -induced Ca2+ release, Ca2+ uptake is confined to ER-close mitochondria, because of the simultaneous activation of the protein kinases. Attenuation of Ca2+ uptake prevents Ca2+ overload of mitochondria and thus protects the cell against apoptosis. On the other hand, all the mitochondria accumulate Ca2+ at a non-inhibited rate during physiological Ca2+ influx through the plasma membrane. Membrane potential is higher in ER-distant mitochondria, providing a bigger driving force for Ca2+ uptake. Our model explains why comparable mitochondrial Ca2+ signals are formed in response to K+ and angiotensin II (equipotent in respect to global cytosolic Ca2+ signals), although only the latter generates high-Ca2+ microdomains. [source] Manipulation of NK cytotoxicity by the IAP family member LivinEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2007Boaz Nachmias Abstract Natural killer (NK) cells are part of the innate immune system, capable of killing tumor and virally infected cells. NK cells induce apoptosis in the target cell by either granule- or receptor-mediated pathways. A set of inhibitory and activation ligands governs NK cell activation. As transformed cells often attempt to evade NK cell killing, up-regulation of a potential anti-apoptotic factor should provide a survival advantage. The inhibitor of apoptosis protein (IAP) family can inhibit apoptosis induced by a variety of stimuli. We have previously described a new IAP family member, termed Livin, which has two splice variants (, and ,) with differential anti-apoptotic activities. In this study, we explore the ability of Livin to inhibit NK cell-induced killing. We demonstrate that Livin,, moderately protects against NK cell killing whereas Livin,, augments killing. We show that Livin,, inhibition in Jurkat cells is apparent upon concomitant activation of an inhibitory signal, suggesting that Livin augments an extrinsic inhibitory signal rather than functioning as an independent inhibitory mechanism. Finally, we demonstrate that detection of both Livin isoforms in melanoma cells correlates with a low killing rate. To date, this is the first evidence that directly demonstrates the ability of IAP to protect against NK cell-induced apoptosis. [source] GABAA -receptor expression in glioma cells is triggered by contact with neuronal cellsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2001Michael Synowitz Abstract The expression of functional GABAA -receptors in glioma cells correlates with low malignancy of tumours and cell lines from glioma lack these receptors. Here we show that contact with neurons induces the expression of functional GABAA -receptors. C6 and F98 glioma cell lines were labelled by recombinant expression of enhanced green fluorescent protein injected into rat brain and studied in acute slices after two to three weeks of tumour growth. The cells responded to GABA or the specific agonist, muscimol with a current typical for GABAA -receptors, as studied with the patch-clamp technique. To get insight into the mechanism of GABAA receptor induction, the C6 or F98 cells were co-cultured with neurons, astrocytes, oligodendrocytes and microglia. Glioma cells expressed functional GABAA receptors within 24 h only in cultures where physical contact to neurons occurred. Activation of GABAA -receptors in the co-cultures attenuated glioma cell metabolism while blockade of the receptors increased metabolism. We conclude that with this form of interaction, neurons can influence tumour behaviour in the brain. [source] RESEARCH ARTICLE: Fungicidal activity of amiodarone is tightly coupled to calcium influxFEMS YEAST RESEARCH, Issue 3 2008Sabina Muend Abstract The antiarrhythmic drug amiodarone has microbicidal activity against fungi, bacteria and protozoa. In Saccharomyces cerevisiae, amiodarone triggers an immediate burst of cytosolic Ca2+, followed by cell death markers. Ca2+ transients are a common response to many forms of environmental insults and toxic compounds, including osmotic and pH shock, endoplasmic reticulum stress, and high levels of mating pheromone. Downstream signaling events involving calmodulin, calcineurin and the transcription factor Crz1 are critical in mediating cell survival in response to stress. In this study we asked whether amiodarone induced Ca2+ influx was beneficial, toxic or a bystander effect unrelated to the fungicidal effect of the drug. We show that downregulation of Ca2+ channel activity in stationary phase cells correlates with increased resistance to amiodarone. In actively growing cells, extracellular Ca2+ modulated the size and shape of the Ca2+ transient and directly influenced amiodarone toxicity. Paradoxically, protection was achieved both by removal of external Ca2+ or by adding high levels of CaCl2 (10 mM) to block the drug induced Ca2+ burst. Our results support a model in which the fungicidal activity of amiodarone is mediated by Ca2+ stress, and highlight the pathway of Ca2+ mediated cell death as a promising target for antifungal drug development. [source] Reduction of type II taste cells correlates with taste dysfunction after X-ray irradiation in miceJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 3 2010M. Yamazaki J Oral Pathol Med (2010) 39: 212,218 Background:, Taste dysfunction that develops after radiotherapy for head and neck cancer impairs patients' quality of life. Although taste cells have been shown to degenerate after exposure to X-ray irradiation, the alteration in taste cell population is unclear. This study investigated the histopathological change of taste bud structure and the taste cell population in X-ray irradiated mice. Methods:, The head and neck region of C57BL/6J male mice was exposed to a single 15 Gy dose of X-ray irradiation and a chronological histopathological analysis of the circumvallate papilla was performed. Preference for sweet taste was measured using the two-bottle preference method. Results:, The histological analysis of the circumvallate papilla revealed that the basal cells had almost disappeared, but that there was not clear change in the spindle-shaped taste cells on day 4 after irradiation. The number of taste cells had decreased on day 8, and then remained unchanged until day 20, after which they increased and recovered to their original number by day 24. There was a more marked decrease in the number of ,-gustducin-positive type II taste cells than in the number of serotonin-positive type III taste cells. Preference for sweet taste measured by the two-bottle preference method was decreased in parallel with taste cell number. Conclusion:, These findings suggest that X-ray irradiation disrupts the basal cells, resulting in a decrease of the number of taste cells, particularly type II taste cells, which may be the cause of radiotherapy-induced taste dysfunction. [source] Over-expression of I,B-kinase-, (IKK,/IKKi) induces secretion of inflammatory cytokines in prostate cancer cell linesTHE PROSTATE, Issue 7 2009Benjamin Péant Abstract BACKGROUND Elevated inflammatory cytokine levels in serum have been associated with advanced stage metastasis-related morbidity in prostate cancer. Several studies have shown that IL-6 and IL-8 can accelerate the growth of human prostate cancer cell lines. Previous studies, in murine embryonic fibroblasts, have shown that I,-B kinase-epsilon (IKK,/IKKi)-deficiency results in the reduction of lipopolysaccharide-mediated expression of IL-6. RESULTS In this study, we report that over-expression of IKK, in hormone-sensitive 22Rv1 and LNCaP prostate cancer cells induces the secretion of several inflammatory cytokines including IL-6 and IL-8. Both of these cytokines are secreted by hormone-refractory PC-3 prostate cancer cells and IKK, knock-down in these cells correlates with a strong decrease in IL-6 secretion. Furthermore, we demonstrate that IKK, over-expression does not induce the activation of the IKK, classical targets NF-,B and IRF-3, two transcription factors involved in the regulation of several cytokines. Finally, we observe that high IKK, expression results in its nuclear translocation, a phenomena that is TBK1-independent. CONCLUSIONS This study identifies IKK, as a potential prostate cancer gene that may favor chronic inflammation and create a tumor-supporting microenvironment that promotes prostate cancer progression, particularly by the induction of IL-6 secretion that may act as a positive growth factor in prostate cancer. Prostate 69: 706,718, 2009. © 2009 Wiley-Liss, Inc. [source] Up-regulation of CD40 with juxtacrine activity in human nonsmall lung cancer cells correlates with poor prognosisCANCER, Issue 3 2008Keidai Ishikawa MD Abstract BACKGROUND. CD40 and its ligand, CD154, play a regulatory role in several signaling pathways among lymphocytes. Recently, it was reported that CD40 is expressed in several malignant tumors. However, the clinical impact of CD40 expression in nonsmall cell lung cancer has not been studied widely. METHODS. One hundred twenty-nine surgical specimens of nonsmall cell lung cancer were assessed immunohistochemically for CD40 and CD154 expression, and that expression was correlated with patients' clinicopathologic parameters and outcome. Subsequently, in vitro analysis of CD40-CD154 signaling was performed. RESULTS. Immunohistochemical staining of tumor cells confirmed that 67 patients (51.9%) were positive for CD40, and 76 patients (58.9%) were positive for CD154. The survival of patients who had tumors that were negative for CD40 was significantly better than the survival of patients who had tumors that were positive for CD40 (P = .0004). Multivariate analysis using a Cox regression model indicated that CD40 expression in cancer cells is an independent, unfavorable prognostic factor (risk ratio, 1.855; P = .0403). By using an in vitro juxtacrine growth factor assay, the growth of LK2 cells (CD40-positive/CD154-negative) was accelerated by CD154-positive cancer cells, such as PC10 cells (CD40-negative/CD154-positive), by a juxtacrine mechanism. CONCLUSIONS. The current results suggested that CD40 expression in tumors is associated with a poor prognosis and that the juxtacrine interaction of CD40-CD154 among cancer cells facilitates the development of malignant potential in nonsmall cell lung cancer. Cancer 2008. © 2008 American Cancer Society. [source] In vivo IL-10 and TGF-, production by PBMC from long-term kidney transplant recipients with excellent graft function: a possible feedback mechanism participating in immunological stabilityCLINICAL TRANSPLANTATION, Issue 2 2004Josefina Alberú Abstract:, Background:, Interleukin-10 (IL-10) and transforming growth factor-, (TGF-,) are Th2-derived multifunctional cytokines that exhibit potent immunoregulatory and anti-inflammatory properties which might prolong graft survival. The aim of this study was to explore whether spontaneous production of IL-10 and TGF-, by blood mononuclear cells correlates with excellent long-term graft function. Methods:, A cross-sectional study was carried out in 32 kidney transplant recipients, without albuminuria, treated with azathioprine and prednisone. Spontaneous IL-10 and TGF-, were measured by enzyme-linked immunosorbent assay in supernatants from 24 h cultured unstimulated peripheral blood mononuclear cells. Both cytokines were also determined in 10 healthy kidney donors. Results:, There was no correlation between IL-10 or TGF-, with any variable tested, namely age, SCr, histocompatibility, and post-transplant follow-up. In vivo IL-10 production displayed a statistical trend to be higher in transplant recipients than in controls (362.3 ± 465, range 12.5,1929.3 pg/ml, and 189 ± 170, range 4.17,485.7 pg/ml, respectively; p = 0.08), whereas no difference was observed in TGF-, among the same groups (134.7 ± 79.2, range 68,421 pg/ml, and 121.4 ± 25.8, range 75,151 pg/ml, respectively). Interestingly, a statistically significant inverse correlation was observed between IL-10 and TGF-, in kidney transplant recipients (p = 0.03). Conclusions:, The higher IL-10 production observed in long-term kidney transplant recipients supports the notion that this cytokine contributes in decreasing allogenic immune responses and allows prolongation of allograft survival. The balance between TGF-, and IL-10 may be of paramount importance in graft acceptance. [source] | |||||||||||||