Albin Pourtier

University of Lille CNRS; Inserm CHU of Lille Pasteur Insitute of Lille · UMR 9020-UMR-S 1277 CANTHER: "Cancer Heterogeneity Plasticity and Resistance to Therapies". F-59000 Lille France

Cellular senescence is a complex cell state that can occur during physiological ageing or after exposure to stress signals, regardless of age. It is a dynamic process that continuously evolves in a context-dependent manner. Senescent cells interact with their microenvironment by producing a heterogenous and plastic secretome referred to as the sene...

A rare but severe complication of curative-intent radiation therapy is the induction of second primary cancers. These cancers preferentially develop not inside the planning target volume (PTV) but around, over several centimeters, after a latency period of 1-40 years. We show here that normal human or mouse dermal fibroblasts submitted to the out-o...

In addition to their well-known role in the control of cellular proliferation and cancer, cell cycle regulators are increasingly identified as important metabolic modulators. Several GWAS have identified SNPs near CDKN2A, the locus encoding for p16INK4a (p16), associated with elevated risk for cardiovascular diseases and type-2 diabetes development...

Ets-1 transcription factor overexpression in breast cancers is associated with invasive features and is associated with a poor prognosis. Beyond its role in driving carcinoma cell invasion, in this study, we wished to determine whether Ets-1 overexpression in cancer cells promotes angiogenesis by creating a paracrine pro-invasive environment for en...

The incidence of carcinomas highly increases with age. However, the initial steps of the age-related molecular carcinogenic processes remain poorly characterized. We previously showed that normal human epidermal keratinocytes spontaneously and systematically escape from senescence to give rise to preneoplastic emerging cells through a process calle...

Senescence is a cell state occurring in vitro and in vivo after successive replication cycles and/or upon exposition to various stressors. It is characterized by a strong cell cycle arrest associated with several molecular, metabolic and morphologic changes. The accumulation of senescent cells in tissues and organs with time plays a role in organis...

Cellular senescence is known as an anti-tumor barrier and is characterized by a number of determinants including cell cycle arrest, senescence associated β-galactosidase activity and secretion of pro-inflammatory mediators. Senescent cells are also subjected to enlargement, cytoskeleton-mediated shape changes and organelle alterations. However, the...

The main characteristic of senescence is its stability which relies on the persistence of DNA damage. We show that unlike fibroblasts, senescent epithelial cells do not activate an ATM-or ATR-dependent DNA damage response (DDR), but accumulate oxidative-stress-induced DNA single-strand breaks (SSBs). These breaks remain unrepaired because of a decr...

Supplementary Figures 1-18 and Supplementary Tables 1-3

The endoplamic reticulum (ER) is a multifunctional organelle critical for the proper folding, assembly of secreted and transmembrane proteins. Perturbations of ER functions cause ER stress, which activates a coordinated system of transcriptional and translational controls called the unfolded protein response (UPR), to cope with accumulation of misf...

Senescence is a non-proliferative state reached by normal cells in response to various stresses, including telomere uncapping, oxidative stress or oncogene activation. In previous reports, we have highlighted that senescent human epidermal keratinocytes have two opposite outcomes: either they die by autophagic programmed cell death or they evade in...

Ets-1 overexpression in human breast cancers is associated with invasiveness and poor prognosis. By overexpressing Ets-1 or a dominant negative mutant in MMT breast cancer cells, we previously highlighted the key role of Ets-1 in coordinating multiple invasive features of these cells. Interestingly, we also noticed that Ets-1 decreased the density...

Cyclooxygenase 2 and release of prostaglandin E2 are involved in many responses including inflammation and are upregulated during cellular senescence. However, little is known about the role of lipid inflammatory mediators in senescence. Here, we investigated the mechanism by which the COX-2/PGE2 axis induces senescence. Using the NS398 specific in...

The incidence of carcinoma increases greatly with aging, but the cellular and molecular mechanisms underlying this correlation are only partly known. It is established that senescent fibroblasts promote the malignant progression of already-transformed cells through secretion of inflammatory mediators. We investigated here whether the senescent fibr...

Typical senescence of NHDFs in vitro. A. Growth curve of NHDFs from donor 2F1966. The young fibroblasts used in this study were taken at 10–20 PDs. Senescent fibroblasts were taken after day 200. This growth curve is representative of more than 30 experiments performed with cells from this donor and is also representative of growth curves obtained...

Corpses induced by MnSOD overexpression have their membranes altered and display oxidative damages NHEKs at the exponential growth phase were infected with AdMnSOD as in Fig. 6. (A) Annexin-V assays performed 10 days post-infection. Both typical large senescent cells and corpses that appeared in the AdMnSOD-infected cultures display some staining o...

Supporting information for Figure 2. A. Densitometric analysis of the western blots of Figure 2B. The density of each band was divided by that of the corresponding actin band, and the obtained value was divided by the value obtained for young NHDFs. B. Western-blot analysis of MMP-1 in concentrated conditioned media from cultures of young (YF) and...

Checking of the efficacy of MMP-1 and MMP-2 inhibition/knockdown in senescent NHDFs and of PAR-1 inhibition/knockdown in PSE-NHEKs. A. In-gel zymography performed to test the ability of the broad-spectrum MMP inhibitor GM6001 to inhibit the proteinolytic activity of MMP-2 present in serum (FGM) or in the media conditioned by young (YF-CM) or senesc...

Complementary results, statistics, and quantification of the results of Figure 1. A. Statistical analysis of the results in Figure 1B. B. Western-blot analysis of E-cadherin and vimentin in young NHEKs cultured in the presence of the different conditioned media that later have given rise to the PSE-NHEKs assayed in Figure 1C. In contrast to the res...

Neither the HGF-SF/c-Met nor the TGF-β1/TGF-bRII axis is involved in SF-CM-induced migration of PSE-NHEKs. A. Western-blot analysis of HGF/SF in YF-CM and SF-CM (media conditioned by NHDFs obtained from donor 2F1966). B. ELISA analysis of the HGF/SF concentration in the same conditioned media. Data are representative of 3 independent experiments pe...

Characteristics of skin sample donors and presence/absence of TWIST-1, PAR-1, and MMPs in the corresponding biopsies. (DOC)

Quantitative analyses of the western blotting experiments of Figures 4 and 5. A. Densitometric analysis of the western blots of Figure 4B, lower panel (A), 4C (B), 5A (C), 5B (D) 5C (E). The optical density of each band was divided by that of the corresponding GAPDH band, and the obtained value was divided by that obtained for the control. (TIF)

PAR-1 activation by CM components is monitored by its internalization and accumulation in bafilomycin-sensitive vesicles. PSE-NHEK/YF-CM cells (upper panels) and PSE-NHEK/SF-CM cells (lower panels) were seeded onto coverglasses, starved for 16 h in KBM to allow PAR-1 re-expression at the membrane (from active transcription), and simultaneously trea...

List of primers used in qRT-PCR experiments. (DOC)

This chapter is devoted to the study of the role of TRP channels in tumorigenesis in vivo using a tumor xenograft model in immunodeficient mice. Either cancerous cells naturally expressing TRP channels, or TRP channel stably expressing cancerous or normal cells, could be injected into immunodeficient mice. After grafting cells may grow in mice and...

La morphogenese de l'arbre vasculaire commence par la formation massive des ebauches de capillaires, suivie du developpement et de la maturation de certaines branches et la regression des autres. C'est l'observation directe et la manipulation de modeles in vivo, et recemment une serie d'experiences de recombinaison homologue, qui ont permis de decr...

The receptor tyrosine kinase Met and its ligand, the hepatocyte growth factor/scatter factor, are essential for embryonic development, whereas deregulation of Met signaling pathways is associated with tumorigenesis and metastasis. The presenilin-regulated intramembrane proteolysis (PS-RIP) is involved in ligand-independent downregulation of Met. Th...

The transcriptional repressor HIC1 (Hypermethylated in Cancer 1) is a tumor suppressor gene inactivated in many human cancers including breast carcinomas. In this study, we show that HIC1 is a direct transcriptional repressor of β-2 adrenergic receptor (ADRB2). Through promoter luciferase activity, chromatin immunoprecipitation (ChIP) and sequentia...

The transcription factor Ets-1 is known to be involved in a broad variety of cellular functions such as cell proliferation, migration, invasion, apoptosis and angiogenesis. In nearly all these reports, the full-length Ets-1 (p51) is commonly considered to be the active form and the role of the Ets-1ΔVII splice variant (p42) has not been addressed....

Senescent keratinocytes accumulate reactive oxygen species NHEKs at the exponential growth phase or at the senescence plateau were suspended and stained with H2-DCFDA. They were then analyzed by flow cytometry for forward (FS, indicative of size, in Y in the dot plot) and side scatter (SS, indicative of granularity, in X in the dot plot) factors an...

Statistical analysis of the results of Figures 11 and 12. (0.61 MB TIF)

Senescence is a state of growth arrest resulting mainly from telomere attrition and oxidative stress. It ultimately leads to cell death. We have previously shown that, in keratinocytes, senescence is induced by NF-kappaB activation, MnSOD upregulation and H(2)O(2) overproduction. We have also shown that senescent keratinocytes do not die by apoptos...

Castration resistance in prostate cancer (PCa) constitutes an advanced, aggressive disease with poor prognosis, associated with uncontrolled cell proliferation, resistance to apoptosis, and enhanced invasive potential. The molecular mechanisms involved in the transition of PCa to castration resistance are obscure. Here, we report that the nonselect...

Studies on human fibroblasts have led to viewing senescence as a barrier against tumorigenesis. Using keratinocytes, we show here that partially transformed and tumorigenic cells systematically and spontaneously emerge from senescent cultures. We show that these emerging cells are generated from senescent cells, which are still competent for replic...

The physiological role, the mechanisms of activation, as well as the endogenous regulators for the non-selective cationic channel TRPV2 are not known so far. In the present work we report that endogenous lysophospholipids such as lysophosphatidylcholine (LPC) and lysophosphatidylinositol (LPI) induce a calcium influx via TRPV2 channel. This activat...

We previously reported that the inactivation of the Ets 1 transcription factor by a specific decoy strategy reduces rat C6 glioma cell proliferation and mmp-9 expression. In the present study, we analysed the effects of the dominant-negative form of Ets 1 (Ets-DB) on rat C6 glioma cell proliferation, migration, invasion, in vivo tumor growth on the...

Acquisition of invasive characteristics is a hallmark of breast carcinoma progression. During this phenomenon, Ets-1 transcription factor overexpression is induced and associated with breast cancer invasiveness, and poor prognosis. We hypothesized that Ets-1 transcription factor could be the orchestrator of a genetic program inducing the expression...

After a finite doubling number, normal cells become senescent, i.e., nonproliferating and apoptosis resistant. Because Rel/nuclear factor (NF)-kappaB transcription factors regulate both proliferation and apoptosis, we have investigated their involvement in senescence. cRel overexpression in young normal keratinocytes results in premature senescence...

Prostate cancer is one of the most diagnosed and mortal cancers in western countries. A major clinical problem is the development of androgen-independent prostate cancer (AIPC) during antihormonal treatment. The molecular mechanisms underlying the change from androgen dependence to independence of these tumors are poorly understood and represent a...

We and others have shown that members of the Ets family of transcription factors are involved in morphogenic properties of endothelial cells in vitro. To investigate the role of these factors in the transcriptional regulation of angiogenesis in vivo, we set up a nontraumatic model that allows daily macroscopic examination of both growth factor- and...

During morphogenesis of the vascular tree, the massive outgrowth of primitive capillaries is followed by the development and the maturation of some capillary branches whereas others regress. The direct observation and the manipulation of in vivo models, including a series of recent knock-out experiments, allow to delineate the mechanisms controllin...

During morphogenesis of the vascular tree, the massive outgrowth of primitive capillaries is followed by the development and the maturation of some capillary branches whereas others regress. The direct observation and the manipulation of in vivo models, including a series of recent knock-out experiments, allow to delineate the mechanisms controllin...

The human multidrug resistance protein (MRP1) confers resistance of cells to a number of different cytostatic drugs and functions as an export pump for glutathione S-conjugates, glucuronides and other amphiphilic anions. The present study details for the first time MRP1-mediated ATP-dependent transport of various glutathione S-conjugates of the bif...

In the mouse, the P-glycoprotein-directed chemosensitizer SDZ PSC 833 could both restore a therapeutic window for doxorubicin against multidrug-resistant tumors, by inhibiting P-glycoprotein function, and increase the anti-cancer drug efficacy against drug-sensitive tumors, by increasing doxorubicin bioavailability. Since the success of such combin...

Multidrug resistance (MDR) of tumor cells may result from overexpression of P-glycoprotein (Pgp) but may be down-modulated by resistance-modifying agents (RMAs). The cyclosporin SDZ PSC 833 and the cyclopeptolide SDZ 280-446 were found to be the strongest RMAs known to date for restoring the sensitivity of MDR cells to anticancer drugs, as well as...

The in vitro proliferative response of mouse spleen cells (SC) to the T-cell mitogen, concanavalin A (ConA), displays a doxorubicin (DOX)-resistant component. This T-cell proliferative response displays a much higher DOX sensitivity in the presence of novel potent inhibitors of P-glycoprotein (Pgp)-mediated multidrug resistance (MDR), the cyclospor...

SDZ 280-446 is a semi-synthetic derivative of a natural cyclic peptolide. Its ability to sensitise in vitro tumour cells whose resistance is due to P-glycoprotein-mediated anticancer-drug efflux was shown using four different pairs of parental drug-sensitive (Par-) and multidrug-resistant (MDR-) cell lines, from three different species (mouse, huma...

Overexpression of P-glycoprotein may cause increased efflux of a variety of anticancer drugs (ACD) leading to multidrug resistance (MDR) of tumor cells. Two sublines of murine monocytic leukemia P388 cells were used, one parental (Par-P388) and one multidrug resistant (MDR-P388). In cell growth inhibition assays in vitro, the Par-P388 cells showed...

The new nonimmunosuppressive cyclosporin analogue, SDZ PSC 833, is a very potent multidrug-resistance modifier. In vitro, it was shown to be at least 10-fold more active than cyclosporin A (Sandimmune), itself more active than verapamil, on most P-glycoprotein-expressing multidrug-resistant (MDR) tumor cell lines. In vivo, SDZ PSC 833 was tested in...

Cyclosporin A (CsA) and FK-506 have similar immunosuppressive activity profiles and cyclophilin-like intracellular targets. Since CsA can reverse the multidrug resistance of tumor cells showing P-glycoprotein-mediated drug efflux, the possible resistance-modulating activity of FK-506 was evaluated in vitro with multidrug-resistant P388 cells and th...