Myoferlin contributes to the metastatic phenotype of pancreatic cancer cells by enhancing their migratory capacity through the control of oxidative phosphorylation

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies with an overall survival of 5%, and is the second cause of death by cancer, mainly linked to its high metastatic aggressiveness. Accordingly, understanding the mechanisms sustaining the PDAC metastatic phenotype remains a priority. In this study, we have generated and used a murine in vivo model to select clones from the human PANC-1 PDAC cell line that exhibit a high propensity to seed and metastasized into the liver. We showed that myoferlin, a protein previously reported to be overexpressed in PDAC, is significantly involved in the migratory abilities of the selected cells. We first report that highly PANC-1 metastatic clones expressed significantly higher myoferlin level than the corresponding low metastatic ones. Using scratch wound and Boyden’s chamber assays, we show that cells expressing high myoferlin level have higher migratory potential than cells characterized by a low myoferlin abundance. Moreover, we demonstrate that myoferlin silencing leads to a migration decrease associated to a reduction of mitochondrial respiration. Since mitochondrial oxidative phosphorylation has been shown to be implicated in the tumor progression and dissemination, our data identify myoferlin as a valid potential therapeutic target in PDAC

Characterization and quality control of antibodies used in ChIP assays.

We present here the very robust characterization and quality control (QC) process that we have established for our polyclonal antibodies, which are mainly directed against targets relevant to the epigenetics field such as modified histones, modifying enzymes, and chromatin-interacting proteins. The final purpose of the characterization and QC is to label antibodies as chromatin immunoprecipitation (ChIP) grade. Indeed, the ChIP method is extensively used in epigenetics to study gene regulation and relies on the use of antibodies to select the protein of interest and then precipitate and identify the DNA associated to it. We have optimized in-house all protocols and reagents needed from the first to the last step of antibody characterization. First, following immunizations, the rabbit crude serum is tested for immune response. Whether or not the antibody is specific is determined in further characterizations. Then, only specific antibodies are tested in ChIP using an optimized method which is ideal for antibody screening. Once QC is established for one antibody, it is used to similarly characterize each antibody batch in order to supply researchers in a reproducible manner with validated antibodies. All in all, this demonstrates that we develop epigenetics research tools based on everyday's researcher's needs by providing batch-specific fully characterized ChIP-grade antibodies

The last 750 ka in loess–palaeosol sequences from northern France: environmental background and dating of the western European Palaeolithic

International audienceThis study presents an overview of Middle Pleistocene loess–palaeosol sequences (LPS) in northern France and discusses the palaeoclimatic significance of the pedosedimentary record in the context of western European LPS and of global climatic cycles for the last 750 ka. In this area, the oldest loess deposits (early Middle Pleistocene) are preserved in sedimentary traps (leeward scarps of fluvial terraces and dissolution sinkholes). They result from local deflation processes reworking Pleistocene sandy fluvial deposits or relicts of Tertiary sands. A large extension of typical calcareous loess over the landscape, the Loess Revolution, is then observed during MIS 6, with heavy mineral assemblages testifying to long‐distance transport from the polar desert area of the dried eastern Channel. A correlation scheme is proposed between the global records of northern France in continental environments and both global palaeoclimatic records and other main western European LPS. After 30 years of research, northern France LPS stand as a fundamental archive of the impact of interglacial–glacial climatic cycles as well as millennial events. Finally, these works provide a robust chronoclimatic framework for the study of the western European Late Acheulean and Middle Palaeolithic and for the relative dating of the various fluvial terraces that they fossilise

The last 400 ka in loess-palaeosols records from Northern France: environmental background and dating of the Palaeolithic

International audienceIn Northern France Quaternary loess-palaeosol sequences represent the main deposits in which Palaeolithic sites are generally recovered. The oldest loess, dating from the Middle Pleistocene, are generally preserved in sedimentary traps formed by the junction between the chalky slopes and the alluvial formations of the Somme River fluvial terrace system or by deep sinkholes (3-5 m) resulting from the dissolution of the chalky substratum on the plateaus. They are mainly resulting from local deflation processes reworking the top of sandy fluvial deposits. A large extension of typical calcareous loess over the whole landscape is only observed from the end of the Saalian (ca. 150-135 ka). The heavy mineral content of these aeolian deposits testifies to a distant transport from the polar desert areas of the dried Eastern Channel (≥ 100 km). Following the last Interglacial (Eemian), the Last glacial (Weichselian) is represented by a sub-continuous loess cover rising up to 7-8 m in thickness in the best locations as leeward slopes. In this large area, pedostratigraphic sequences from the last Interglacial-glacial cycle have been intensely studied, especially in the frame of rescue archaeological programs that have provided hundreds of individual sequences from test-pits or excavations and numerous archaeological layers. The pedostratigraphic sequences from the last Interglacial-glacial cycle exhibit a regular pedosedimentary pattern including well identified pedological and periglacial marker horizons that can be followed towards the East at least in Belgium and Germany. This approach leads to a detailed pedostratigraphic and chronostratigraphic scheme that represents a unique database to discuss the relations between Palaeolithic occupations and environment in Europe. It can be summarised by the succession of four main chrono-climatic phases following the erosion of the eemian brown leached soil during MIS 5d: (1) Early-glacial (112-72 ka) including a phase with grey forest soils (Early-glacial A: MIS 5d-5a) and a phase with steppe-like soils (Early-glacial B: end of MIS 5a), (2) Lower Pleniglacial (ca.70-58 ka): erosion, colluvial deposits then first typical homogeneous loess deposits marking the first occurrence of typical periglacial conditions, (3) Middle Pleniglacial (ca. 58-30): intense and short erosive episode (thermokarst) / deposition of bedded colluviums reworking the whole underlying units / development of a brown soil complex and weak aeolian deposition during most of MIS 3, (4) Upper Pleniglacial (ca. 30-15 ka): main network of large ice-wedge casts / drastic increase in loess sedimentation including tundra-gley horizons and large Ice wedge casts. In this context, the data show that Human occupation of Northern France was discontinuous during the Last glacial, with a clear concentration of Palaeolithic remains during the Early-glacial in forest-steppe contexts under continental climate. Only a few occupations were attributed to the Lower Pleniglacial and to the course of the MPGL and a gap is attested between ca. 25 and ca.15 ka mainly during the period of maximal loess deposition. It thus appears to be a strong relationship between the intensity of human occupation and the climatic and environmental context. This could be conditioned by the relative abundance of large fauna, itself linked to vegetation density, as indicated by the extremely sparse biomass contemporaneous with the UPGL loess. Even if data are much more scattered for the Middle Pleistocene, a markedly concentration of Palaeolithic occupations is observed during the Early-glacial transitional phases (Early-glacial MIS 11/10, 9/8 and 7/6)

The prevention of spontaneous apoptosis of follicular lymphoma B cells by a follicular dendritic cell line: involvement of caspase-3, caspase-8 and c-FLIP.

BACKGROUND: Follicular lymphoma, the neoplastic counterpart of germinal center B cells, typically recapitulates a follicular architecture. Several observations point to the crucial role of the cellular microenvironment in the development and/or progression of follicular lymphoma cells in vivo. The aim of our study was to characterize the spontaneous apoptosis of follicular lymphoma cells in vitro, and the modulation of this apoptosis by follicular dendritic cells. DESIGN AND METHODS: We used a cell line derived from follicular dendritic cells to model the functional interactions of these cells and lymphoma cells in co-culture. Follicular lymphoma cells were isolated from tissue biopsies. Apoptosis was quantified by flow cytometry and apoptotic pathways were investigated by western blotting. RESULTS: The spontaneous apoptosis of follicular lymphoma cells in vitro involves the activation of caspases-3 and -8 but not of caspase-9, occurs despite persistent high levels of BCL-2 and MCL-1, and is associated with down-regulation of c-FLIP(L). Spontaneous apoptosis of follicular lymphoma cells is partially prevented by co-culture with the follicular dendritic cells, which prevents activation of caspase-8, caspase-3 and induces an upregulation of c-FLIP(L). Using neutralizing antibodies, we demonstrated that interactions involving CD54 (ICAM-1), CD106 (VCAM-1) and CD40 are implicated in this biological process. CONCLUSIONS: Follicular dendritic cells constitute a useful tool to study the functional interactions between follicular lymphoma cells and follicular dendritic cells in vitro. Understanding the molecular mechanisms involved in these protective interactions may lead to the identification of therapeutic agents that might suppress the survival and growth of follicular lymphoma cells

Upper Pleistocene Loess-Palaeosols Records from Northern France in the European Context: Environmntal Background and Dating of the Middle Palaeolithic

International audienceIn Northern France the loess cover from the Last Glacial (Weichselian) is represented by a subcontinuous cover rising up to 8-9 m in thickness in the best locations as leeward slopes (E-NE exposition). In this large area, pedostratigraphic sequences from the Last Interglacial-glacial cycle (Eemian-Weichselian) have been intensely studied, especially in the frame of very active rescue archaeological programs that have provided hundreds of individual sequences from test-pits or excavations. In spite of variations in the thickness of the different stratigraphic units, driven by differences in geomorphological contexts and in location of the profiles regarding to sources of aeolian material, the pedostratigraphic sequences from the last Interglacial-glacial cycle exhibit a particularly constant pedosedimentary pattern including well identified pedological and periglacial marker horizons that can be followed towards the East in Belgium, in Germany and even in Central-Europe.The main objective of the presentation is to propose a summary of the pedostratigraphic sequence from Northern France and a global correlation scheme with surrounding areas. The great homogeneity that is evidenced in the response of Western European environments to rapid climatic changes provides a solid base for the discussion of relations between man, climate and environment since the Eemian Interglacial. In Northern France, the synthesis of the observations carried out on no more than 80 sequences during the last 20 years allows to draw a highly detailed pedostratigraphic and chronostratigraphic scheme that represents a unique database to discuss the relations between Palaeolithic occupations and environment. This frame can be summarised by the succession of four main chrono-climatic phases that follow the erosion of the interglacial brown leached soil (Eemian) during MIS 5d:1. Early-glacial (112-72 ky): including a phase with grey forest soils (Early-glacial A: ~MIS 5a-5d GIS interstadials 21-24) and a phase with steppe-like soils (Early-glacial B: end of MIS 5a GIS 19 & 20).2. Lower Pleniglacial (~70-58 ky): first typical homogeneous loess deposits marking the first occurrence of typical periglacial conditions.3. Middle Pleniglacial (~ 58-30 ky): intense and short erosive episode (thermokarst)/deposition of thick body of bedded colluviums reworking the whole underlying units/development of a soil, or of a soil complex (Saint-Acheul-Villiers-Adam Complex) during most of MIS 3.4. Upper Pleniglacial (~30-15 ky): main network of large ice-wedge casts/drastic acceleration of loess sedimentation (mainly between 27 and 22 ky) including tundra-gley horizons and large Ice wedge casts.In this context, the data concerning the last climatic cycle (Eemian-Weichselian) show that Human occupation of Northern France was clearly discontinuous, with a clear concentration of remains during the Early-glacial in forest-steppe contexts developed under continental climate. Only a few occupations were attributed to the Lower Pleniglacial and to the course of the MPGL. A total abandon of the region is attested between ca. 25 and ca. 15 ky mainly during the period of maximal loess deposition. Given these results there appears to be a strong relationship between the intensity of human occupation and the climatic and environmental context. This relationship appears to be conditioned by the relative abundance of large fauna, itself linked to vegetation density, as indicated by the extremely sparse biomass contemporaneous with the UPGL loess

Chapitre V. Quaternaire et géoarchéologie de la Préhistoire

Introduction Contexte géologique et géomorphologique régional Le bassin de la Somme est un bassin hydrographique de faible superficie dont le substratum antéquaternaire est constitué par la craie du Crétacé supérieur, roche dans l’ensemble très homogène, présentant une grande porosité et qui constitue l’une des originalités du secteur étudié. Les grandes lignes du réseau hydrographique y sont guidées par des structures tectoniques d’axe NW/SE, comme le synclinal de la Somme. Au cours des péri..

Myoferlin Contributes to the Metastatic Phenotype of Pancreatic Cancer Cells by Enhancing Their Migratory Capacity Through the Control of Oxidative Phosphorylation

peer reviewedPancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies with an overall survival of 5%, and is the second cause of death by cancer, mainly linked to its high metastatic aggressiveness. Accordingly, understanding the mechanisms sustaining the PDAC metastatic phenotype remains a priority. In this study, we have generated and used a murine in vivo model to select clones from the human PANC-1 PDAC cell line that exhibit a high propensity to seed and metastasized into the liver. We showed that myoferlin, a protein previously reported to be overexpressed in PDAC, is significantly involved in the migratory abilities of the selected cells. We first report that highly PANC-1 metastatic clones expressed significantly higher myoferlin level than the corresponding low metastatic ones. Using scratch wound and Boyden’s chamber assays, we show that cells expressing high myoferlin level have higher migratory potential than cells characterized by a low myoferlin abundance. Moreover, we demonstrate that myoferlin silencing leads to a migration decrease associated to a reduction of mitochondrial respiration. Since mitochondrial oxidative phosphorylation has been shown to be implicated in the tumor progression and dissemination, our data identify myoferlin as a valid potential therapeutic target in PDAC