Endoplasmic Reticulum Calcium Pumps and Tumor Cell Differentiation.

Endoplasmic reticulum (ER) calcium homeostasis plays an essential role in cellular calcium signaling, intra-ER protein chaperoning and maturation, as well as in the interaction of the ER with other organelles. Calcium is accumulated in the ER by sarco/endoplasmic reticulum calcium ATPases (SERCA enzymes) that generate by active, ATP-dependent transport, a several thousand-fold calcium ion concentration gradient between the cytosol (low nanomolar) and the ER lumen (high micromolar). SERCA enzymes are coded by three genes that by alternative splicing give rise to several isoforms, which can display isoform-specific calcium transport characteristics.

Validation of Novaprep(®) HQ+ liquid-based cytology medium for high-risk human papillomavirus detection by hc2.

Background: Preanalytical conditions determine the reliability and validity of bioassays. Therefore, the analytic performances of biological tests need to be determined when preanalytical steps differ from those recommended by the manufacturer. The objective of the study was to assess the analytic performance of the hc2 test for the detection of high-risk HPV DNA from cells stored in the new Novaprep® HQ+ medium.

Efferocytosis of apoptotic human papillomavirus-positive cervical cancer cells by human primary fibroblasts.

Background Information: Efficient clearance of apoptotic cells, named efferocytosis, is a fundamental physiological process for tissue development and homeostasis. The contribution of non-professional phagocytes like fibroblasts to efferocytosis has been established, although the underlying mechanisms are not well understood. We recently demonstrated that horizontal DNA transfer can occur through the uptake of apoptotic human papillomavirus-positive cancer cells by human primary fibroblasts leading to their transformation.

Apoptotic HPV positive cancer cells exhibit transforming properties.

Previous studies have shown that DNA can be transferred from dying engineered cells to neighboring cells through the phagocytosis of apoptotic bodies, which leads to cellular transformation. Here, we provide evidence of an uptake of apoptotic-derived cervical cancer cells by human mesenchymal cells. Interestingly, HeLa (HPV 18+) or Ca Ski (HPV16+) cells, harboring integrated high-risk HPV DNA but not C-33 A cells (HPV-), were able to transform the recipient cells.

A step further toward glyphosate-induced epidermal cell death: involvement of mitochondrial and oxidative mechanisms.

A deregulation of programmed cell death mechanisms in human epidermis leads to skin pathologies. We previously showed that glyphosate, an extensively used herbicide, provoked cytotoxic effects on cultured human keratinocytes, affecting their antioxidant capacities and impairing morphological and functional cell characteristics. The aim of the present study, carried out on the human epidermal cell line HaCaT, was to examine the part of apoptosis plays in the cytotoxic effects of glyphosate and the intracellular mechanisms involved in the apoptotic events.

Position-referenced microscopy for live cell culture monitoring.

Position-referenced microscopy (PRM) is based on smart sample holders that integrate a position reference pattern (PRP) in their depth, allowing the determination of the lateral coordinates with respect to the sample-holder itself. Regions of interest can thus be retrieved easily after culture dish transfers from a cell incubator to the microscope stage. Images recorded at different instants in time are superimposed in a common coordinate system with subpixel accuracy.

Sodium butyrate with UCN-01 has marked antitumour activity against cervical cancer cells.

Aim: The effect of combining sodium butyrate (NaB), a histone deacetylase inhibitor, and 7-hydroxy-staurosporine (UCN-01) on cytotoxicity in human cervical carcinoma cells was evaluated.

Materials And Methods: HeLa and CaSki cells were treated using NaB alone or in combination with staurosporine (STS) or its analog UCN-01. Cytotoxicity was determined by flow cytometry and morphological assays.

Spatiotemporal activation of caspase-dependent and -independent pathways in staurosporine-induced apoptosis of p53wt and p53mt human cervical carcinoma cells.

Background Information: Caspase-dependent and -independent death mechanisms are involved in apoptosis in a variety of human carcinoma cells treated with antineoplastic compounds. Our laboratory has reported that p53 is a key contributor of mitochondrial apoptosis in cervical carcinoma cells after staurosporine exposure. However, higher mitochondrial membrane potential dissipation and greater DNA fragmentation were observed in p53wt (wild-type p53) HeLa cells compared with p53mt (mutated p53) C-33A cells.

Caspase-8 prevents sustained activation of NF-kappaB in monocytes undergoing macrophagic differentiation.

Caspases have demonstrated several nonapoptotic functions including a role in the differentiation of specific cell types. Here, we show that caspase-8 is the upstream enzyme in the proteolytic caspase cascade whose activation is required for the differentiation of peripheral-blood monocytes into macrophages. On macrophage colony-stimulating factor (M-CSF) exposure, caspase-8 associates with the adaptor protein Fas-associated death domain (FADD), the serine/threonine kinase receptor-interacting protein 1 (RIP1) and the long isoform of FLICE-inhibitory protein FLIP.

Identification of proteins cleaved downstream of caspase activation in monocytes undergoing macrophage differentiation.

We have shown previously that caspases were specifically involved in the differentiation of peripheral blood monocytes into macrophages while not required for monocyte differentiation into dendritic cells. To identify caspase targets in monocytes undergoing macrophagic differentiation, we used the human monocytic leukemic cell line U937, whose macrophagic differentiation induced by exposure to 12-O-tetradecanoylphorbol 13-acetate (TPA) can be prevented by expression of the baculovirus caspase-inhibitory protein p35. A comparative two-dimensional gel proteomic analysis of empty vector- and p35-transfected cells after 12 h of exposure to 20 nm TPA, followed by mass spectrometry analysis, identified 38 differentially expressed proteins.

Vital functions for lethal caspases.

Caspases are a family of cysteine proteases expressed as inactive zymogens in virtually all animal cells. These enzymes play a central role in most cell death pathways leading to apoptosis but growing evidences implicate caspases also in nonapoptotic functions. Several of these enzymes, activated in molecular platforms referred to as inflammasomes, play a role in innate immune response by processing some of the cytokines involved in inflammatory response.

Translocation of the inhibitor of apoptosis protein c-IAP1 from the nucleus to the Golgi in hematopoietic cells undergoing differentiation: a nuclear export signal-mediated event.

The caspase inhibitor and RING finger-containing protein cellular inhibitor of apoptosis protein 1 (c-IAP1) has been shown to be involved in both apoptosis inhibition and signaling by members of the tumor necrosis factor (TNF) receptor family. The protein is regulated transcriptionally (eg, is a target for nuclear factor-kappaB [NF-kappaB]) and can be inhibited by mitochondrial proteins released in the cytoplasm upon apoptotic stimuli. The present study indicates that an additional level of regulation of c-IAP1 may be cell compartmentalization.

Bcl-2 proteins: targets and tools for chemosensitisation of tumor cells.

Proteins of the Bcl-2 family share one or several Bcl-2 homology (BH) regions and behave as pro- or anti-apoptotic proteins. Prosurvival members such as Bcl-2 and Bcl-X(L) are supposed to preserve mitochondrial outer membrane integrity, thus preventing the release of soluble apoptogenic molecules. Pro-apoptotic members include BH3-only proteins that act as sensors of cellular damage and initiate the death process and Bax-like proteins that act downstream of BH3-only proteins to permeabilise the mitochondrial outer membrane.

Expression of WASP and Scar1/WAVE1 actin-associated proteins is differentially modulated during differentiation of HL-60 cells.

The Wiskott-Aldrich Syndrome (WAS) is a disease associated with mutations in the WAS gene and characterised by developmental defects in haematopoietic cells such as myeloid cells. The Wiskott-Aldrich Syndrome protein (WASP)-family includes Scar1 and WASP, which are key regulators of actin reorganization in motile cells. To understand the roles of Scar1 and WASP in myeloid cells and their cytoskeletal control in haematopoietic tissues, we have explored their expression during differentiation of the promyeloid cell line HL-60.

Involvement of the Arp2/3 complex and Scar2 in Golgi polarity in scratch wound models.

Cell motility and cell polarity are essential for morphogenesis, immune system function, and tissue repair. Many animal cells move by crawling, and one main driving force for movement is derived from the coordinated assembly and disassembly of actin filaments. As tissue culture cells migrate to close a scratch wound, this directional extension is accompanied by Golgi apparatus reorientation, to face the leading wound edge, giving the motile cell inherent polarity aligned relative to the wound edge and to the direction of cell migration.

Enhancement of ATRA-induced cell differentiation by inhibition of calcium accumulation into the endoplasmic reticulum: cross-talk between RAR alpha and calcium-dependent signaling.

Sarco-endoplasmic reticulum calcium ATPase (SERCA) enzymes control calcium-induced cellular activation by accumulating calcium from the cytosol into the endoplasmic reticulum (ER). To better understand the role of SERCA proteins and cellular calcium homeostasis in all-trans retinoic acid (ATRA)-induced differentiation, we investigated the effect of pharmacologic inhibition of SERCA-dependent calcium uptake into the ER on ATRA-induced differentiation of the HL-60 myelogenous and the NB4 promyelocytic cell lines. SERCA inhibitors di-tert-butyl-benzohydroquinone (tBHQ), thapsigargin, and cyclopiazonic acid significantly enhanced the induction of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and CD11b marker expression induced by suboptimal concentrations of ATRA (50 nM) in both cell lines.

Identification and characterisation of a novel human isoform of Arp2/3 complex subunit p16-ARC/ARPC5.

The Arp2/3 complex is an actin filament nucleator that activates regulated actin assembly in response to extracellular signals. The mammalian complex is composed of seven subunits, the smallest of which is known as ARPC5 or p16-Arc. We have identified a human cDNA sequence with homology to ARPC5 and here provide evidence that this encodes a novel ARPC5 isoform.