Endoplasmic reticulum Ca2+-homeostasis is altered in small and non-small cell lung cancer cell lines

<p>Abstract</p> <p>Background</p> <p>Knowledge of differences in the cellular physiology of malignant and non-malignant cells is a prerequisite for the development of cancer treatments that effectively kill cancer without damaging normal cells. Calcium is a ubiquitous signal molecule that is involved in the control of proliferation and apoptosis. We aimed to investigate if the endoplasmic reticulum (ER) Ca²⁺-homeostasis is different in lung cancer and normal human bronchial epithelial (NHBE) cells.</p> <p>Methods</p> <p>The intracellular Ca²⁺-signaling was investigated using fluorescence microscopy and the expression of Ca²⁺-regulating proteins was assessed using Western Blot analysis.</p> <p>Results</p> <p>In a Small Cell Lung Cancer (H1339) and an Adeno Carcinoma Lung Cancer (HCC) cell line but not in a Squamous Cell Lung Cancer (EPLC) and a Large Cell Lung Cancer (LCLC) cell line the ER Ca²⁺-content was reduced compared to NHBE. The reduced Ca²⁺-content correlated with a reduced expression of SERCA 2 pumping calcium into the ER, an increased expression of IP₃R releasing calcium from the ER, and a reduced expression of calreticulin buffering calcium within the ER. Lowering the ER Ca²⁺-content with CPA led to increased proliferation NHBE and lung cancer cells.</p> <p>Conclusion</p> <p>The significant differences in Ca²⁺-homeostasis between lung cancer and NHBE cells could represent a new target for cancer treatments.</p

Orai1 contributes to the establishment of an apoptosis-resistant phenotype in prostate cancer cells

The molecular nature of calcium (Ca2+)-dependent mechanisms and the ion channels having a major role in the apoptosis of cancer cells remain a subject of debate. Here, we show that the recently identified Orai1 protein represents the major molecular component of endogenous store-operated Ca2+ entry (SOCE) in human prostate cancer (PCa) cells, and constitutes the principal source of Ca2+ influx used by the cell to trigger apoptosis. The downregulation of Orai1, and consequently SOCE, protects the cells from diverse apoptosis-inducing pathways, such as those induced by thapsigargin (Tg), tumor necrosis factor α, and cisplatin/oxaliplatin. The transfection of functional Orai1 mutants, such as R91W, a selectivity mutant, and L273S, a coiled-coil mutant, into the cells significantly decreased both SOCE and the rate of Tg-induced apoptosis. This suggests that the functional coupling of STIM1 to Orai1, as well as Orai1 Ca2+-selectivity as a channel, is required for its pro-apoptotic effects. We have also shown that the apoptosis resistance of androgen-independent PCa cells is associated with the downregulation of Orai1 expression as well as SOCE. Orai1 rescue, following Orai1 transfection of steroid-deprived cells, re-established the store-operated channel current and restored the normal rate of apoptosis. Thus, Orai1 has a pivotal role in the triggering of apoptosis, irrespective of apoptosis-inducing stimuli, and in the establishment of an apoptosis-resistant phenotype in PCa cells

Flavonoids in prevention of diseases with respect to modulation of Ca-pump function

Flavonoids, natural phenolic compounds, are known as agents with strong antioxidant properties. In many diseases associated with oxidative/nitrosative stress and aging they provide multiple biological health benefits. Ca2+-ATPases belong to the main calcium regulating proteins involved in the balance of calcium homeostasis, which is impaired in oxidative/nitrosative stress and related diseases or aging. The mechanisms of Ca2+-ATPases dysfunction are discussed, focusing on cystein oxidation and tyrosine nitration. Flavonoids act not only as antioxidants but are also able to bind directly to Ca2+-ATPases, thus changing their conformation, which results in modulation of enzyme activity

Method triangulation to assess different aspects of food safety culture in food service operations

The advantages and added value of applying method triangulation to gain a more comprehensive evaluation of the prevailing food safety culture in catering establishments is illustrated by means of a case study. Three methods are applied assessing the food safety culture in food service operations of a Flemish University spread over different locations in the city of Ghent, but centrally managed. Each method sheds light on one of the aspects of 'food safety culture' as defined in the food safety culture conceptual model, in which food safety culture is considered as the interplay between a techno-managerial route/aspect and a human route/aspect Two system and product related methods, being internal audits and verification of monitoring data of Critical Control Points (CCPs) as part of the HACCP system, both assessing the performance of the food safety management system and as such belonging to the techno-managerial route, are compared with a people related method using the food safety climate self-assessment tool, which is belonging to the human route. By triangulation of these three methods different aspects of the food safety culture at the different locations could be investigated, illustrating how single-method derived results could lead to wrong conclusions. Moreover, by combining the assessment methods case by case, locations in which the hazard of optimistic bias and complacency might exist, can be identified. As such, more tailored and location specific strategies for improvement of food safety management and/or food safety culture can be put in place

Overexpression of an alpha(1H) (Ca(v)3.2) T-type calcium channel during neuroendocrine differentiation of human prostate cancer cells

International audienceno abstrac

A Security Architecture for Web 2.0 Applications

The problem of supporting the secure execution of potentially malicious third-party applications has received a considerable amount of attention in the past decade. In this paper we describe a security architecture for Web 2.0 applications that supports the flexible integration of a variety of advanced technologies for such secure execution of applications, including run-time monitoring, static verification and proof-carrying code. The architecture also supports the execution of legacy applications that have not been developed to take advantage of our architecture, though it can provide better performance and additional services for applications that are architecture-aware. A prototype of the proposed architecture has been built that offers substantial security benefits compared to standard (state-of-practice) security architectures, even for legacy applications

Caspase-mediated cleavage of Beclin-1 inactivates Beclin-1-induced autophagy and enhances apoptosis by promoting the release of proapoptotic factors from mitochondria

Autophagy and apoptosis are two important and interconnected stress-response mechanisms. However, the molecular interplay between these two pathways is not fully understood. To study the fate and function of autophagic proteins at the onset of apoptosis, we used a cellular model system in which autophagy precedes apoptosis. IL-3 depletion of Ba/F3 cells caused caspase (casp)-mediated cleavage of Beclin-1 and PI3KC3, two crucial components of the autophagy-inducing complex. We identified two casp cleavage sites in Beclin-1, TDVD133 and DQLD149, cleavage at which yields fragments lacking the autophagyinducing capacity. Noteworthy, the C-terminal fragment, Beclin-1-C, localized predominantly at the mitochondria and sensitized the cells to apoptosis. Moreover, on isolated mitochondria, recombinant Beclin-1-C was able to induce the release of proapoptotic factors. These findings point to a mechanism by which casp-dependent generation of Beclin-1-C creates an amplifying loop enhancing apoptosis upon growth factor withdrawal