Quality of Life in COVID-19 Outpatients: A Long-Term Follow-Up Study

Background: The long-term issues faced by COVID-19 survivors remain unclear. Symptoms may persist for several months, even in non-hospitalized patients, probably impacting the quality of life. Objective: To assess the health-related quality of life of outpatients one year after SARS-CoV-2 infection. Design, Settings, and Participants: This prospective multicentre study, conducted in France from February 2020 to February 2022, compared 150 COVID-19 cases (PCR+ and/or CT scan+) and 260 controls (PCR-) selected from a database of four COVID centres. Main outcomes: Health-related quality of life assessed using the EQ-5D-5L scale. Results: COVID-19 outpatients (n = 96) had significantly lower health-related quality of life than controls (n = 81) one year after SARS-CoV-2 infection: the EQ-5D-5L index averaged 0.87 in cases and 0.95 in controls (p = 0.002); the EQ- VAS averaged 78 in cases and 86.7 in controls (p < 0.001). This alteration in quality of life was more intense in the areas of pain or discomfort and daily activities. Conclusions: This study is the first to show an alteration in the quality of life of COVID-19 outpatients after one year. Appropriate guidance and community rehabilitation programs are required for outpatients with persistent symptoms of COVID-19. Research must continue to confirm these results in larger cohorts.

Prescription of benzodiazepines and Z-drugs among older patients in primary care: a French, national, cohort study

BACKGROUND

In France, general practitioners (GPs) prescribe benzodiazepines and Z-drugs (BZD/ZDs) widely, and especially to older adults. Several characteristics of patients and/or GPs linked to BZD/ZD overprescription have been described in the general population but not among older patients in primary care.

OBJECTIVES

To estimate the proportion of GP consultations by patients aged 65 and over that resulted in a BZD/ZD prescription, and determine whether any GP-related factors predicted BZD/ZD overprescription in this setting.

METHODS

We analyzed sociodemographic and practice-related GP characteristics, and aggregated data on consultations recorded prospectively by 117 GPs in a database between 2000 and 2010. Next, we used logistic regression models to look for factors potentially associated with BZD/ZD overprescription (defined as an above-median prescription rate).

RESULTS

The GPs' mean age at inclusion was 47.4 (7.1), and 87.9% were male. During the study period, the median (95% confidence interval) proportion of consultations with patients aged 65 and over resulting in a BZD/ZD prescription was 21.8% (18.1-26.1) (range per GP: 5-34.1%). In a multivariable analysis, a greater number of chronic disease (OR [95% CI] = 2.10 [1.22-3.64]), a greater number of drugs prescribed per consultation (5.29 [2.72-10.28]), and shorter study participation were independently associated with BZD/ZD overprescription.

CONCLUSIONS

BZD/ZD overprescription was associated with a greater chronic disease burden and the number of drugs prescribed per consultation but not with any sociodemographic or practice-related GP characteristics. Targeted actions are needed to help GPs limit their prescription of BZD/ZDs to older patients with multiple comorbidities and polypharmacy.

Upregulated Apelin Signaling in Pancreatic Cancer Activates Oncogenic Signaling Pathways to Promote Tumor Development

Despite decades of effort in understanding pancreatic ductal adenocarcinoma (PDAC), there is still a lack of innovative targeted therapies for this devastating disease. Herein, we report the expression of apelin and its receptor, APJ, in human pancreatic adenocarcinoma and its protumoral function. Apelin and APJ protein expression in tumor tissues from patients with PDAC and their spatiotemporal pattern of expression in engineered mouse models of PDAC were investigated by immunohistochemistry. Apelin signaling function in tumor cells was characterized in pancreatic tumor cell lines by Western blot as well as proliferation, migration assays and in murine orthotopic xenograft experiments. In premalignant lesions, apelin was expressed in epithelial lesions whereas APJ was found in isolated cells tightly attached to premalignant lesions. However, in the invasive stage, apelin and APJ were co-expressed by tumor cells. In human tumor cells, apelin induced a long-lasting activation of PI3K/Akt, upregulated β-catenin and the oncogenes c-myc and cyclin D1 and promoted proliferation, migration and glucose uptake. Apelin receptor blockades reduced cancer cell proliferation along with a reduction in pancreatic tumor burden. These findings identify the apelin signaling pathway as a new actor for PDAC development and a novel therapeutic target for this incurable disease.

Real-Time Observation and Analysis of Magnetomechanical Actuation of Magnetic Nanoparticles in Cells

The origin of cell death in the magnetomechanical actuation of cells induced by magnetic nanoparticle motion under low-frequency magnetic fields is still elusive. Here, a miniaturized electromagnet fitted under a confocal microscope is used to observe in real time cells specifically targeted by superparamagnetic nanoparticles and exposed to a low-frequency rotating magnetic field. Our analysis reveals that the lysosome membrane is permeabilized in only a few minutes after the start of magnetic field application, concomitant with lysosome movements toward the nucleus. Those events are associated with disorganization of the tubulin microtubule network and a change in cell morphology. This miniaturized electromagnet will allow a deeper insight into the physical, molecular, and biological process occurring during the magnetomechanical actuation of magnetic nanoparticles.

Magneto-mechanical destruction of cancer-associated fibroblasts using ultra-small iron oxide nanoparticles and low frequency rotating magnetic fields

The destruction of cells using the mechanical activation of magnetic nanoparticles with low-frequency magnetic fields constitutes a recent and interesting approach in cancer therapy. Here, we showed that superparamagnetic iron oxide nanoparticles as small as 6 nm were able to induce the death of pancreatic cancer-associated fibroblasts, chosen as a model. An exhaustive screening of the amplitude, frequency, and type (alternating vs. rotating) of magnetic field demonstrated that the best efficacy was obtained for a rotating low-amplitude low-frequency magnetic field (1 Hz and 40 mT), reaching a 34% ratio in cell death induction; interestingly, the cell death was not maximized for the largest amplitudes of the magnetic field. State-of-the-art kinetic Monte-Carlo simulations able to calculate the torque undergone by assemblies of magnetic nanoparticles explained these features and were in agreement with cell death experiments. Simulations showed that the force generated by the nanoparticles once internalized inside the lysosome was around 3 pN, which is in principle not large enough to induce direct membrane disruption. Other biological mechanisms were explored to explain cell death: the mechanical activation of magnetic nanoparticles induced lysosome membrane permeabilization and the release of the lysosome content and cell death was mediated through a lysosomal pathway depending on cathepsin-B activity. Finally, we showed that repeated rotating magnetic field exposure halted drastically the cell proliferation. This study established a proof-of-concept that ultra-small nanoparticles can disrupt the tumor microenvironment through mechanical forces generated by mechanical activation of magnetic nanoparticles upon low-frequency rotating magnetic field exposure, opening new opportunities for cancer therapy.

Predictive factors for non-participation or partial participation in breast, cervical and colorectal cancer screening programmes†

BACKGROUND

No study has investigated factors associated with non-participation or partial participation in the different combination patterns of screening programmes for all three cancers, that is, breast, colorectal and cervical cancer.

METHODS

In a retrospective cohort study, we sought to describe combinations of cancer screening participation rates among women in the Val-de-Marne area of France and to identify individual and contextual factors associated with non-participation or partial participation.

RESULTS

Women aged between 50 and 65 and who were eligible for all three screening programmes (n = 102 219) were analysed in multilevel logistic models, with the individual as the Level 1 variable and the place of residence as the Level 2 variable. The women who did not participate in any of the screening programmes were 34.4%, whereas 30.1%, 24% and 11.5% participated in one, two or all three screening programmes, respectively. Age below 55, a previous false-positive mammography, prior opportunistic mammography only, no previous mammography, membership of certain health insurance schemes (all P < 0.05) and residence in a deprived area (P < 0.001) were independently associated with non-participation or partial participation. We observed a stronger effect of deprivation on non-participation in all three cancers than in combinations of screening programmes.

CONCLUSION

Our findings suggest that the health authorities should focus on improving cancer screenings in general rather than screenings for specific types of cancer, especially among younger women and those living in the most socially deprived areas.

Combined Treatments of Magnetic Intra-Lysosomal Hyperthermia with Doxorubicin Promotes Synergistic Anti-Tumoral Activity

Doxorubicin is a cytotoxic drug used for the treatment of many cancer types. However, its significant dose-related adverse effects including cardiotoxicity may hamper its efficiency. Moreover, the multidrug resistance that appears during treatments limits anti-cancer therapies. Hyperthermia has been introduced as an adjuvant anti-cancer therapy and presents promising opportunities especially in combination with chemotherapy. However, hyperthermia methods including standard magnetic hyperthermia do not discriminate between the target and the surrounding normal tissues and can lead to side effects. In this context, a Magnetic Intra-Lysosomal Hyperthermia (MILH) approach, which occurs without perceptible temperature rise, has been developed. We previously showed that minute amounts of iron oxide magnetic nanoparticles targeting the gastrin receptor (CCK2R) are internalized by cancer cells through a CCK2R-dependent physiological process, accumulated into their lysosomes and kill cancer cells upon high frequency alternating magnetic field (AMF) application through lysosomal cell death. Here, we show that the combination of MILH with doxorubicin increases the efficiency of the eradication of endocrine tumor cells with synergism. We also demonstrate that these two treatments activate two different cell death pathways that are respectively dependent on Caspase-1 and Caspase-3 activation. These findings will result in the development of new anti-tumoral, intra-lysosomal-thermo/chemotherapy with better curative effects than chemotherapy alone and that are devoid of adverse effects linked to standard hyperthermia approaches.

Efficacy of nurse-led and general practitioner-led comprehensive geriatric assessment in primary care: protocol of a pragmatic three-arm cluster randomised controlled trial (CEpiA study)

INTRODUCTION

Older patients raise therapeutic challenges, because they constitute a heterogeneous population with multimorbidity. To appraise this complexity, geriatricians have developed a multidimensional comprehensive geriatric assessment (CGA), which may be difficult to apply in primary care settings. Our primary objective was to compare the effect on morbimortality of usual care compared with two complex interventions combining educational seminars about CGA: a dedicated geriatric hotline for general practitioners (GPs) and CGA by trained nurses or GPs.

METHODS AND ANALYSIS

The Clinical Epidemiology and Ageing study is an open-label, pragmatic, multicentre, three-arm, cluster randomised controlled trial comparing two intervention groups and one control group. Patients must be 70 years or older with a long-term illness or with unscheduled hospitalisation in the past 3 months (750 patients planned). This study involves volunteering GPs practising in French primary care centres, with randomisation at the practice level. The multifaceted interventions for interventional arms comprise an educational interactive multiprofessional seminar for GPs and nurses, a geriatric hotline dedicated to GPs in case of difficulties and the performance of a CGA updated to primary care. The CGA is systematically performed by a nurse in arm 1 but is GP-led on a case-by-case basis in arm 2. The primary endpoint is a composite criterion comprising overall death, unscheduled hospitalisations, emergency admissions and institutionalisation within 12 months after inclusion. Intention-to-treat analysis will be performed using mixed-effects logistic regression models, with adjustment for potential confounders.

ETHICS AND DISSEMINATION

The protocol was approved by an appropriate ethics committee (CPP Ile-de-France IV, Paris, France, approval April 2015;15 664). This study is conducted according to principles of good clinical practice in the context of current care and will provide useful knowledge on the clinical benefits achievable by CGA in primary care.

TRIAL REGISTRATION NUMBER

NCT02664454; Pre-results.

Internalized Receptor for Glucose-dependent Insulinotropic Peptide stimulates adenylyl cyclase on early endosomes

Until very recently, G-protein dependent signal of GPCRs was thought to originate exclusively from the plasma membrane and internalized GPCRs were considered silent. Here, we demonstrated that, once internalized and located in the membrane of early endosomes, glucose-dependent Insulinotropic receptor (GIPR) continues to trigger production of cAMP and PKA activation. Direct evidence is based on identification of the active form of Gαs in early endosomes containing GIPR using a genetically encoded GFP tagged nanobody, and on detection of a distinct FRET signal accounting for cAMP production at the surface of endosomes containing GIP, compared to endosomes without GIP. Furthermore, decrease of the sustained phase of cAMP production and PKA activation kinetics as well as reversibility of cAMP production and PKA activity following GIP washout in cells treated with a pharmacological inhibitor of GIPR internalization, and continuous increase of cAMP level over time in the presence of dominant-negative Rab7, which causes accumulation of early endosomes in cells, were noticed. Hence the GIPR joins the few GPCRs which signal through G-proteins both at plasma membrane and on endosomes.

Internalization and desensitization of the human glucose-dependent-insulinotropic receptor is affected by N-terminal acetylation of the agonist

How incretins regulate presence of their receptors at the cell surface and their activity is of paramount importance for the development of therapeutic strategies targeting these receptors. We have studied internalization of the human Glucose-Insulinotropic Polypeptide receptor (GIPR). GIP stimulated rapid robust internalization of the GIPR, the major part being directed to lysosomes. GIPR internalization involved mainly clathrin-coated pits, AP-2 and dynamin. However, neither GIPR C-terminal region nor β-arrestin1/2 was required. Finally, N-acetyl-GIP recognized as a dipeptidyl-IV resistant analogue, fully stimulated cAMP production with a ∼15-fold lower potency than GIP and weakly stimulated GIPR internalization and desensitization of cAMP response. Furthermore, docking N-acetyl-GIP in the binding site of modeled GIPR showed slighter interactions with residues of helices 6 and 7 of GIPR compared to GIP. Therefore, incomplete or partial activity of N-acetyl-GIP on signaling involved in GIPR desensitization and internalization contributes to the enhanced incretin activity of this peptide.

Real-Time Analysis of Magnetic Hyperthermia Experiments on Living Cells under a Confocal Microscope

Combining high-frequency alternating magnetic fields (AMF) and magnetic nanoparticles (MNPs) is an efficient way to induce biological responses through several approaches: magnetic hyperthermia, drug release, controls of gene expression and neurons, or activation of chemical reactions. So far, these experiments cannot be analyzed in real-time during the AMF application. A miniaturized electromagnet fitting under a confocal microscope is built, which produces an AMF of frequency and amplitude similar to the ones used in magnetic hyperthermia. AMF application induces massive damages to tumoral cells having incorporated nanoparticles into their lysosomes without affecting the others. Using this setup, real-time analyses of molecular events occurring during AMF application are performed. Lysosome membrane permeabilization and reactive oxygen species production are detected after only 30 min of AMF application, demonstrating they occur at an early stage in the cascade of events leading eventually to cell death. Additionally, lysosomes self-assembling into needle-shaped organization under the influence of AMF is observed in real-time. This experimental approach will permit to get a deeper insight into the physical, molecular, and biological process occurring in several innovative techniques used in nanomedecine based on the combined use of MNPs and high-frequency magnetic fields.

[Restructuring of ambulatory care in France: proposals for the management of hypertensive patients]

One of the factors responsible for the creation of multidisciplinary health centres is the growth of outpatient management of multiple chronic conditions. Based on a classification of hypertensive patients into eight groups, the authors discuss the interrelations between health care organization and modification of management. They discuss the effects of modification of health care structures and the need to create new job positions for the purposes of coordination, support of patients in the form of therapeutic education and support ofyoung professionals in multidisciplinary practice. External effects are improvement of office-hospital flows, especially with the development of second-line consultant roles and improved management of patient admissions and discharges. However, to ensure sustainable changes, there must be a change of mentalities with new modalities of remuneration of private practitioners and development of the health information system.

Drp1 is dispensable for apoptotic cytochrome c release in primed MCF10A and fibroblast cells but affects Bcl-2 antagonist-induced respiratory changes

BACKGROUND AND PURPOSE

Dynamin-related protein 1 (Drp1) mediates mitochondrial fission and is thought to promote Bax/Bak-induced cytochrome c release during apoptosis. Conformationally active Bax, Bak and Bax/Bak-activating BH3-only proteins, such as Bim, are restrained by anti-apoptotic Bcl-2 proteins in cells that are 'primed for death'. Inhibition of Bcl-2/Bcl-xL/Bcl-w by the antagonist ABT-737 causes rapid apoptosis of primed cells. Hence, we determined whether Drp1 is required for cytochrome c release, respiratory alterations and apoptosis of cells that are already primed for death.

EXPERIMENTAL APPROACH

We tested the Drp1 inhibitor mdivi-1 for inhibition of cytochrome c release in MCF10A cells primed by Bcl-2 overexpression. We measured ATP synthesis-dependent, -independent and cytochrome c-limited maximal oxygen consumption rates (OCRs) and cell death of immortalized wild-type (WT) and Drp1 knockout (KO) mouse embryonic fibroblasts (MEFs) treated with ABT-737.

KEY RESULTS

Mdivi-1 failed to attenuate ABT-737-induced cytochrome c release. ABT-737 decreased maximal OCR measured in the presence of uncoupler in both WT and Drp1 KO MEF, consistent with respiratory impairment due to release of cytochrome c. However, Drp1 KO MEF were slightly less sensitive to this ABT-737-induced respiratory inhibition compared with WT, and were resistant to an initial ABT-737-induced increase in ATP synthesis-independent O2 consumption. Nevertheless, caspase-dependent cell death was not reduced. Pro-apoptotic Bax was unaltered, whereas Bak was up-regulated in Drp1 KO MEF.

CONCLUSIONS AND IMPLICATIONS

The findings indicate that once fibroblast cells are primed for death, Drp1 is not required for apoptosis. However, Drp1 may contribute to ABT-737-induced respiratory changes and the kinetics of cytochrome c release.

Targeting a G-protein-coupled receptor overexpressed in endocrine tumors by magnetic nanoparticles to induce cell death

Nanotherapy using targeted magnetic nanoparticles grafted with peptidic ligands of receptors overexpressed in cancers is a promising therapeutic strategy. However, nanoconjugation of peptides can dramatically affect their properties with respect to receptor recognition, mechanism of internalization, intracellular trafficking, and fate. Furthermore, investigations are needed to better understand the mechanism whereby application of an alternating magnetic field to cells containing targeted nanoparticles induces cell death. Here, we designed a nanoplatform (termed MG-IONP-DY647) composed of an iron oxide nanocrystal decorated with a ligand of a G-protein coupled receptor, the cholecystokinin-2 receptor (CCK2R) that is overexpressed in several malignant cancers. MG-IONP-DY647 did not stimulate inflammasome of Raw 264.7 macrophages. They recognized cells expressing CCK2R with a high specificity, subsequently internalized via a mechanism involving recruitment of β-arrestins, clathrin-coated pits, and dynamin and were directed to lysosomes. Binding and internalization of MG-IONP-DY647 were dependent on the density of the ligand at the nanoparticle surface and were slowed down relative to free ligand. Trafficking of CCK2R internalized with the nanoparticles was slightly modified relative to CCK2R internalized in response to free ligand. Application of an alternating magnetic field to cells containing MG-IONP-DY647 induced apoptosis and cell death through a lysosomal death pathway, demonstrating that cell death is triggered even though nanoparticles of low thermal power are internalized in minute amounts by the cells. Together with pioneer findings using iron oxide nanoparticles targeting tumoral cells expressing epidermal growth factor receptor, these data represent a solid basis for future studies aiming at establishing the proof-of-concept of nanotherapy of cancers using ligand-grafted magnetic nanoparticles specifically internalized via cell surface receptors.

Oxidative stress induced by inactivation of TP53INP1 cooperates with KrasG12D to initiate and promote pancreatic carcinogenesis in the murine pancreas

Tumor protein p53-induced nuclear protein 1 (TP53INP1) is involved in cell stress response. Its expression is lost at the pancreatic intraepithelial neoplasia 1b (PanIN1b)/PanIN2 stage of pancreatic carcinogenesis. Our objective was to determine whether TP53INP1 loss of expression contributes to pancreatic cancer formation in a conditional KrasG12D mouse model. We generated Kras-INP1KO mice using LSL-Kras(G12D/+);Pdx1-Cre(+/-) mice (Kras mice) and TP53INP1(-/-) mice. Analysis of pancreases during ageing shows that in the presence of activated Kras, TP53INP1 loss of expression accelerated PanIN formation and increased pancreatic injury and the number of high-grade lesions as compared with what occurs in Kras mice. Moreover, cystic lesions resembling intraductal papillary mucinous neoplasm (IPMN) were observed as early as 2 months of age. Remarkably, TP53INP1 is down-regulated in human IPMN. Activation of the small GTPase Rac1 shows that more oxidative stress is generated in Kras-INP1KO than in Kras mice pancreas despite elevated levels of the Nrf2 antioxidant regulator. We firmly establish the link between Kras-INP1KO pancreatic phenotype and oxidative stress with rescue of the phenotype by the antioxidant action of N-acetylcysteine. Our data provide in vivo functional demonstration that TP53INP1 deficiency accelerates progression of pancreatic cancer, underlining its role in the occurrence of IPMN and highlighting the importance of TP53INP1 in the control of oxidative status during development of pancreatic cancer.

Distinct CCK-2 receptor conformations associated with β-arrestin-2 recruitment or phospholipase-C activation revealed by a biased antagonist

Seven-transmembrane receptors (7TMRs), also termed G protein-coupled receptors (GPCRs), form the largest class of cell surface membrane receptors, involving several hundred members in the human genome. Nearly 30% of marketed pharmacological agents target 7TMRs. 7TMRs adopt multiple conformations upon agonist binding. Biased agonists, in contrast to non-biased agonists, are believed to stabilize conformations preferentially activating either G-protein- or β-arrestin-dependent signaling pathways. However, proof that cognate conformations of receptors display structural differences within their binding site where biased agonism initiates, are still lacking. Here, we show that a non-biased agonist, cholecystokinin (CCK) induces conformational states of the CCK2R activating Gq-protein-dependent pathway (CCK2R(G)) or recruiting β-arrestin2 (CCK2R(β)) that are pharmacologically and structurally distinct. Two structurally unrelated antagonists competitively inhibited both pathways. A third ligand (GV150013X) acted as a high affinity competitive antagonist on CCK2R(G) but was nearly inefficient as inhibitor of CCK2R(β). Several structural elements on both GV150013X and in CCK2R binding cavity, which hinder binding of GV150013X only to the CCK2R(β) were identified. At last, proximity between two conserved amino acids from transmembrane helices 3 and 7 interacting through sulfur-aromatic interaction was shown to be crucial for selective stabilization of the CCK2R(β) state. These data establish structural evidence for distinct conformations of a 7TMR associated with β-arrestin-2 recruitment or G-protein coupling and validate relevance of the design of biased ligands able to selectively target each functional conformation of 7TMRs.

Characterization of a novel five-transmembrane domain cholecystokinin-2 receptor splice variant identified in human tumors

The cholecystokinin-2 receptor (CCK2R), is expressed in cancers where it contributes to tumor progression. The CCK2R is over-expressed in a sub-set of tumors, allowing its use in tumor targeting with a radiolabel ligand. Since discrepancies between mRNA levels and CCK2R binding sites were noticed, we searched for abnormally spliced variants in tumors from various origins having been previously reported to frequently express cholecystokinin receptors, such as medullary thyroid carcinomas, gastrointestinal stromal tumors, leiomyomas and leiomyosarcomas, and gastroenteropancreatic tumors. A variant of the CCK2R coding for a putative five-transmembrane domains receptor has been cloned. This variant represented as much as 6% of CCK2R levels. Ectopic expression in COS-7 cells revealed that this variant lacks biological activity due to its sequestration in endoplasmic reticulum. When co-expressed with the CCK2R, this variant diminished membrane density of the CCK2R and CCK2R-mediated activity (phospholipase-C and ERK activation). In conclusion, a novel splice variant acting as a dominant negative on membrane density of the CCK2R may be of importance for the pathophysiology of certain tumors and for their in vivo CCK2R-targeting.

TP53INP1 decreases pancreatic cancer cell migration by regulating SPARC expression

Tumor protein 53 induced nuclear protein 1 (TP53INP1) is a p53 target gene that induces cell growth arrest and apoptosis by modulating p53 transcriptional activity. TP53INP1 interacts physically with p53 and is a major player in the p53-driven oxidative stress response. Previously, we demonstrated that TP53INP1 is downregulated in an early stage of pancreatic cancerogenesis and when restored is able to suppress pancreatic tumor development. TP53INP1 downregulation in pancreas is associated with an oncogenic microRNA miR-155. In the present work, we studied the effects of TP53INP1 on cell migration. We found that TP53INP1 inactivation correlates with increased cell migration both in vivo and in vitro. The impact of TP53INP1 expression on cell migration was studied in different cellular contexts: mouse embryonic fibroblast and different pancreatic cancer cell lines. Its expression decreases cell migration by the transcriptional downregulation of secreted protein acidic and rich in cysteine (SPARC). SPARC is a matrix cellular protein, which governs diverse cellular functions and has a pivotal role in regulating cell-matrix interactions, cellular proliferation and migration. SPARC was also showed to be upregulated in normal pancreas and in pancreatic intraepithelial neoplasia lesions in a pancreatic adenocarcinoma mouse model only in the TP53INP1-deficient animals. This novel TP53INP1 activity on the regulation of SPARC expression could explain in part its tumor suppressor function in pancreatic adenocarcinoma by modulating cellular spreading during the metastatic process.

Id3 modulates cellular localization of bHLH Ptf1-p48 protein

Ptf1-p48 is a pancreas-specific bHLH transcriptional protein, which, in the normal adult pancreas, shows a restricted expression in acinar cells where it is predominantly localized in the nucleus and activates the transcription of exocrine-specific genes. Ptf1-p48 partners with two proteins to form the PTF1 active complex: a bHLH E-protein and suppressor of hairless RBP-J. Cytoplasmic mislocalization of Ptf1-p48 has been reported in pancreatic pathologies, suggesting its contribution in the early steps of pancreatic carcinogenesis. The aim of the our work was to elucidate the mechanisms regulating Ptf1-p48 subcellular localization. We hypothesized a role of Id proteins acting in a dominant-negative fashion by heterodimerizing with bHLH proteins. We reproduced Ptf1-p48 cytoplasmic mislocalization in acinar AR4-2J cells and demonstrated that a proliferative signal elicited by gastrin leads to increases in Id3 protein expression and levels of Id3/E47 and Id3/Ptf1-p48 interactions, and a decrease in the level of E47/Ptf1-p48 interaction. By contrast, Id3 silencing reversed the cytoplasmic mislocalization of Ptf1-p48 induced by gastrin. As E47 is responsible for the nuclear import of the PTF1 complex, disruption of this complex via Id3 interactions with both E47 and Ptf1-p48 appears to induce cytoplasmic mislocalization of Ptf1-p48. We then found that Ptf1-p48 is either absent or mislocalized in the cytoplasm and Id3 is overexpressed in human and murine pancreatic preneoplastic lesions. Our data provide novel insight into the regulation of Ptf1-p48 function and provide evidence that Ptf1-p48 cytoplasmic mislocalization and Id3 overexpression are early events in pancreatic cancer progression.

Reg genes are CCK2 receptor targets in ElasCCK2 mice pancreas

We previously demonstrated that expression of the gastrin receptor, CCK2R, in pancreatic acini of transgenic ElasCCK2 mice induced alteration of acinar morphology and differentiation, increased sensitivity to a carcinogen and development of preneoplastic lesions and tumours. Reg proteins are suggested to be involved in pancreatic cancer and in regeneration of endocrine pancreas. Reg I gene is a known target of gastrin. We examined whether an expression of CCK2R in the pancreatic acini of ElasCCK2 mice is linked to induction of Reg proteins expression. We analyzed Reg expression by Western-blot and immunohistochemistry in pancreas from ElasCCK2 and control mice. Islet neogenesis, glucose homeostasis, insulin secretion and content were also evaluated. Reg I is exclusively produced in acini in ElasCCK2 and control mice. In tumoral pancreas, Reg I and Reg III proteins are expressed in duct-like cells in preneoplastic lesions or in the periphery of tumours and in adjacent acini. The expression of Reg III proteins is increased in ElasCCK2 pancreas before the development of preneoplastic lesions in a subpopulation of islet cells and in small islet-like cell clusters dispersed within the acinar tissue. Several criteria of an enhanced neogenesis are fulfilled in ElasCCK2 pancreas. Moreover, ElasCCK2 mice have an improved response to glucose load, an increased insulin secretion and a doubling of insulin content compared to control mice. We show that Reg proteins are targets of CCK2R activation and are induced during early steps of carcinogenesis in ElasCCK2 mice pancreas. Alterations of exocrine tissue homeostasis in ElasCCK2 pancreas concomitantly activate regenerative responses of the endocrine pancreas possibly linked to paracrine actions of Reg III proteins.

Reg genes are CCK2 receptor targets in ElasCCK2 mice pancreas

We previously demonstrated that expression of the gastrin receptor, CCK2R, in pancreatic acini of transgenic ElasCCK2 mice induced alteration of acinar morphology and differentiation, increased sensitivity to a carcinogen and development of preneoplastic lesions and tumours. Reg proteins are suggested to be involved in pancreatic cancer and in regeneration of endocrine pancreas. Reg I gene is a known target of gastrin. We examined whether an expression of CCK2R in the pancreatic acini of ElasCCK2 mice is linked to induction of Reg proteins expression. We analyzed Reg expression by Western-blot and immunohistochemistry in pancreas from ElasCCK2 and control mice. Islet neogenesis, glucose homeostasis, insulin secretion and content were also evaluated. Reg I is exclusively produced in acini in ElasCCK2 and control mice. In tumoral pancreas, Reg I and Reg III proteins are expressed in duct-like cells in preneoplastic lesions or in the periphery of tumours and in adjacent acini. The expression of Reg III proteins is increased in ElasCCK2 pancreas before the development of preneoplastic lesions in a subpopulation of islet cells and in small islet-like cell clusters dispersed within the acinar tissue. Several criteria of an enhanced neogenesis are fulfilled in ElasCCK2 pancreas. Moreover, ElasCCK2 mice have an improved response to glucose load, an increased insulin secretion and a doubling of insulin content compared to control mice. We show that Reg proteins are targets of CCK2R activation and are induced during early steps of carcinogenesis in ElasCCK2 mice pancreas. Alterations of exocrine tissue homeostasis in ElasCCK2 pancreas concomitantly activate regenerative responses of the endocrine pancreas possibly linked to paracrine actions of Reg III proteins.

Reg genes are CCK2 receptor targets in ElasCCK2 mice pancreas

We previously demonstrated that expression of the gastrin receptor, CCK2R, in pancreatic acini of transgenic ElasCCK2 mice induced alteration of acinar morphology and differentiation, increased sensitivity to a carcinogen and development of preneoplastic lesions and tumours. Reg proteins are suggested to be involved in pancreatic cancer and in regeneration of endocrine pancreas. Reg I gene is a known target of gastrin. We examined whether an expression of CCK2R in the pancreatic acini of ElasCCK2 mice is linked to induction of Reg proteins expression. We analyzed Reg expression by Western-blot and immunohistochemistry in pancreas from ElasCCK2 and control mice. Islet neogenesis, glucose homeostasis, insulin secretion and content were also evaluated. Reg I is exclusively produced in acini in ElasCCK2 and control mice. In tumoral pancreas, Reg I and Reg III proteins are expressed in duct-like cells in preneoplastic lesions or in the periphery of tumours and in adjacent acini. The expression of Reg III proteins is increased in ElasCCK2 pancreas before the development of preneoplastic lesions in a subpopulation of islet cells and in small islet-like cell clusters dispersed within the acinar tissue. Several criteria of an enhanced neogenesis are fulfilled in ElasCCK2 pancreas. Moreover, ElasCCK2 mice have an improved response to glucose load, an increased insulin secretion and a doubling of insulin content compared to control mice. We show that Reg proteins are targets of CCK2R activation and are induced during early steps of carcinogenesis in ElasCCK2 mice pancreas. Alterations of exocrine tissue homeostasis in ElasCCK2 pancreas concomitantly activate regenerative responses of the endocrine pancreas possibly linked to paracrine actions of Reg III proteins.

Involvement of cholecystokinin 2 receptor in food intake regulation: hyperphagia and increased fat deposition in cholecystokinin 2 receptor-deficient mice

The role of cholecystokinin (CCK) as a satiety factor has been extensively documented. Although most work implies that CCK1 receptor mediates the control of food intake, a contributing role for CCK2 receptor (CCK2R) in the CCK-induced satiety cannot be totally excluded. The hypothesis that CCK2R invalidation disrupts regulatory pathways with impact on feeding behavior was examined in CCK2R(-/-) mice. CCK2R(-/-) mice developed obesity that was associated with hyperphagia. Obesity was related with increased fat deposition resulting from adipocyte hypertrophy. Expression of several adipokines was dysregulated consistently with obesity. Moreover, obesity was associated with disturbed glucose homeostasis as revealed by increased fasting glycemia and insulinemia, impaired glucose tolerance, and hepatic insulin resistance in CCK2R(-/-) mice. In vitro analysis of isolated adipocytes metabolism was consistent with increased storage but preserved insulin sensitivity. Suppression of feeding and concomitant increased expression of hypothalamic proopiomelanocortin after intracerebroventricular injection of gastrin into control mice demonstrates that hypothalamic CCK2 receptors mediate inhibition of food intake. Comparative analysis of hypothalamic mediator gene expression in fed knockout and control mice demonstrated overexpression of ghrelin receptors in CCK2R(-/-) mice, indicating up-regulation of orexigenic pathways. This effect was also observed after body weight normalization, indicating a causative role in the development of hyperphagia and obesity of CCK2R(-/-) mice. Our results give evidence that CCK2 receptor activity plays a contributing regulatory role in the control of food intake.

Cholecystokinin-2 receptor modulates cell adhesion through beta 1-integrin in human pancreatic cancer cells

Several lines of evidence suggest that gastrin and the CCK-2 receptor (CCK2R) could contribute to pancreatic carcinogenesis by modulating processes such as proliferation, cell adhesion or migration. In the current study, we used a 'cancer gene array' and identified beta1-integrin subunit as a new gastrin-regulated gene in human pancreatic cancer cells. We also demonstrated that Src family kinases and the phosphatidylinositol-3-kinase (PI-3-kinase) pathway play a crucial role in the expression of beta1-integrin induced by gastrin. Our results also showed that gastrin modulates cell-substrate adhesion via beta1-integrin. Indeed, using blocking anti-beta1-integrin monoclonal antibodies, we completely reversed the increase in cell-substrate adhesion induced by gastrin. In addition, we observed that in response to gastrin, beta1-integrin is tyrosine phosphorylated by Src family kinases and associates with paxillin, a scaffold protein involved in focal adhesion and integrin signalling. This mechanism might be involved in gastrin-induced cell adhesion. Moreover, we showed in vivo that targeted CCK2R expression in the pancreas of Elas-CCK2 mice leads to the overexpression of beta1-integrin. This process may contribute to pancreatic tumour development observed in these transgenic animals.

Expression of cholecystokinin-2/gastrin receptor in the murine pancreas modulates cell adhesion and cell differentiation in vivo

The presence of gastrin and cholecystokinin-2 (CCK2) receptors in human preneoplastic and neoplastic gastrointestinal lesions suggests a role in cancer development. In addition to the growth-promoting action of gastrin, recently a role of the cholecystokinin-2/gastrin receptor (CCK2-R) modulating cellular morphology in cultured epithelial cells has been shown. Here, we have investigated in transgenic (ElasCCK2) mice whether ectopic expression of human CCK2-R in the exocrine pancreas affected epithelial differentiation. Cellular localization of cell adhesion molecules, differentiation markers, and transcription factors was determined using immunofluorescence techniques. Before tumor formation, expression and subcellular localization of proteins of the adherens junction complex, differentiation markers, and transcription factors were altered in ElasCCK2 exocrine pancreas, indicating an evolution from an acinar to a ductal phenotype. Loss of cell polarity, defective secretion, and loss of intercellular adhesion in acini of ElasCCK2 mice was confirmed by ultrastructural analysis. Finally, expression of the transgene in mice treated with the carcinogen azaserine resulted in enhanced size of preneoplastic lesions as well as an increased degree of acinar-ductal transdifferentiation. Thus, these data represent the first evidence for the CCK2-R modulating intercellular adhesion and cell fate in vivo and show that these alterations may contribute to enhanced sensitivity of ElasCCK2 pancreas to chemical carcinogens.

Molecular mechanism underlying partial and full agonism mediated by the human cholecystokinin-1 receptor

The cholecystokinin-1 receptor (CCK1R) is a G protein-coupled receptor (GPCR) that regulates important physiological functions. As for other GPCRs, the molecular basis of full and partial agonism is still far from clearly understood. In the present report, using both laboratory experiments and molecular modeling approaches, we have investigated the partial agonism mechanism of JMV 180, on the human CCK1R. We first showed that efficacy of the CCK1R to activate phospholipase C is dependent on the correct orientation of the C-terminal end of peptidic ligands toward residue Phe(330) of helix VI. We have previously reported that a single mutation of Met(121) (helix III) markedly reduced the receptor-mediated inositol phosphate production upon stimulation by CCK. Computational simulations predicted that residue 121 affected orientation of the C-terminal end of CCK, thus suggesting that the molecular complex with a reduced inositol phosphate production observed with the mutated CCK1R resembles that resulting from binding of JMV 180 to the WT-CCK1R. Pharmacological, biochemical, and functional characterizations of the two receptor.ligand complexes with decreased abilities to signal were carried out in different cell types. We found that they presented the same features, such as total dependence of inositol phosphate production to Galpha(q) expression, single affinity of binding sites, insensitivity of binding to non-hydrolyzable GTP, absence of GTPgamma[S(35)] binding following agonist stimulation, similarity of dose-response curves for amylase secretion, and incapacity to induce acute pancreatitis in pancreatic acini. We concluded that helices VI and III of the CCK1R are functionally linked through the CCK1R agonist binding site and that positioning of the C-terminal ends of peptidic agonists toward Phe(330) of helix VI is responsible for extent of phospholipase C activation through Galpha(q) coupling. Given the potential therapeutic interest of partial agonists such as JMV 180, our structural data will serve for target structure-based design of new CCK1R ligands.

Transgenic expression of CCK2 receptors sensitizes murine pancreatic acinar cells to carcinogen-induced preneoplastic lesions formation

In humans, initial events of pancreatic carcinogenesis remain unknown, and the question of whether this cancer, which has a ductal phenotype, exclusively arises from duct cells has been raised. Previous studies have demonstrated that transgenic expression of the CCK2 receptor in acinar cells of ElasCCK2 mice plays a role in the development of pancreatic neoplasia. The aim of our study was to examine initial steps of carcinogenesis in ElasCCK2 mice, adding a supplementary defect by using a chemical carcinogen, azaserine. Results of posttreatment sequential immunohistochemical examinations and quantifications demonstrate that mice responded to azaserine. Transition of acinar cells into duct-like cells expressing Pdx1 and gastrin, as well as proliferation of acinar cells, were transiently observed in both transgenic and control mice. The carcinogen also induced formation of preneoplastic lesions, adenomas, exhibiting properties of autonomous growth. Importantly, expression of the CCK2 receptor increased the susceptibility of pancreas to azaserine. Indeed, treated ElasCCK2 mice exhibited larger areas of pancreatic acinar-ductal transition, increased cellular proliferation as well as larger adenomas areas vs. control mice. These amplified responses may be related to auto/paracrine stimulation of CCK2 receptor by gastrin expressed in newly formed duct-like cells. Our results demonstrate that activation of CCK2 receptor and azaserine result in cumulative effects to favor the emergence of a risk situation that is a potential site for initiation of carcinogenesis.

Essential interaction of Egr-1 at an islet-specific response element for basal and gastrin-dependent glucagon gene transactivation in pancreatic alpha-cells

The peptide hormone gastrin is secreted from G cells of the gastric antrum and is the main inducer of gastric acid secretion via activation of its receptor the cholecystokinin 2 (CCK2) receptor. Both gastrin and CCK2 receptors are also transiently detected in the fetal pancreas and believed to exert growth/differentiation effects during endocrine pancreatic development. We demonstrated previously that whereas gastrin expression is extinguished in adult pancreas, CCK2 receptors are present in human glucagon-producing cells where their activation stimulates glucagon secretion. Based on these findings, we investigate in the present study whether gastrin regulates glucagon gene expression. To this aim, the CCK2 receptor was stably expressed into a glucagon-producing pancreatic islet cell line, and a glucagon-reporter fusion gene was transiently transfected in this new cellular model. We report that gastrin stimulates glucagon gene expression in glucagon-producing pancreatic cells. By using progressively 5'-increased sequences of the glucagon gene, gastrin responsiveness was located within the minimal promoter. Moreover, we clearly identified early growth response protein 1 (Egr-1) as an essential transcription factor interacting with the islet cell-specific G4 element. Egr-1 was shown to be essential for basal and gastrin-dependent glucagon gene transactivation. Furthermore, our results demonstrate that the MEK1/ERK1/2 pathway couples the CCK2 receptor to nuclearization and DNA binding of Egr-1. In conclusion, our data provide new information concerning the transcriptional regulation of the glucagon gene. Moreover they open new working hypothesis with reference to a potential role of gastrin in glucagon-producing pancreatic cells.

Transgenic mice expressing cholecystokinin 2 receptors in the pancreas

Several studies argue for the presence of CCK2 receptors in the human pancreas but their physiological role in normal exocrine pancreas and their contribution to pancreatic pathologies is unknown. In order to allow an easy investigation of their pancreatic function, we created the ElasCCK2 transgenic mice expressing the human receptor in pancreatic exocrine cells. In this model, the CCK2 receptor is specifically expressed in the exocrine pancreas and has typical molecular and binding features. It is functional and mediates enzyme release but stimulating concentrations of agonists are not physiological. Results of phenotypic and long-term studies show that activation of CCK2 receptors stimulates growth of the pancreas in correlation with an increase of acinar tissue. This finding is also consistent with the demonstration of an efficient coupling of the transgenic receptor to protein synthesis. Alterations in pancreatic histology and development of preneoplastic lesions are apparent from postnatal day 50. Moreover, expression of this G-protein-coupled receptor leads to the development of tumours in older animals with an incidence of 15%. Although tumours have distinct phenotypes they all exhibit ductular structures. Immunohistochemical analysis of these structures shows their acinar origin. These data, linking for the first time the development of pancreatic carcinogenesis in vivo to the expression of the CCK2 receptor, support a key role of the CCK2 receptor in the initiation of pancreatic cancer. Moreover, ElasCCK2 mice provide a model for carcinogenesis by transformation and dedifferentiation of acinar cells.

Transgenic mice expressing cholecystokinin 2 receptors in the pancreas

Several studies argue for the presence of CCK2 receptors in the human pancreas but their physiological role in normal exocrine pancreas and their contribution to pancreatic pathologies is unknown. In order to allow an easy investigation of their pancreatic function, we created the ElasCCK2 transgenic mice expressing the human receptor in pancreatic exocrine cells. In this model, the CCK2 receptor is specifically expressed in the exocrine pancreas and has typical molecular and binding features. It is functional and mediates enzyme release but stimulating concentrations of agonists are not physiological. Results of phenotypic and long-term studies show that activation of CCK2 receptors stimulates growth of the pancreas in correlation with an increase of acinar tissue. This finding is also consistent with the demonstration of an efficient coupling of the transgenic receptor to protein synthesis. Alterations in pancreatic histology and development of preneoplastic lesions are apparent from postnatal day 50. Moreover, expression of this G-protein-coupled receptor leads to the development of tumours in older animals with an incidence of 15%. Although tumours have distinct phenotypes they all exhibit ductular structures. Immunohistochemical analysis of these structures shows their acinar origin. These data, linking for the first time the development of pancreatic carcinogenesis in vivo to the expression of the CCK2 receptor, support a key role of the CCK2 receptor in the initiation of pancreatic cancer. Moreover, ElasCCK2 mice provide a model for carcinogenesis by transformation and dedifferentiation of acinar cells.

Transgenic mice expressing cholecystokinin 2 receptors in the pancreas

Several studies argue for the presence of CCK2 receptors in the human pancreas but their physiological role in normal exocrine pancreas and their contribution to pancreatic pathologies is unknown. In order to allow an easy investigation of their pancreatic function, we created the ElasCCK2 transgenic mice expressing the human receptor in pancreatic exocrine cells. In this model, the CCK2 receptor is specifically expressed in the exocrine pancreas and has typical molecular and binding features. It is functional and mediates enzyme release but stimulating concentrations of agonists are not physiological. Results of phenotypic and long-term studies show that activation of CCK2 receptors stimulates growth of the pancreas in correlation with an increase of acinar tissue. This finding is also consistent with the demonstration of an efficient coupling of the transgenic receptor to protein synthesis. Alterations in pancreatic histology and development of preneoplastic lesions are apparent from postnatal day 50. Moreover, expression of this G-protein-coupled receptor leads to the development of tumours in older animals with an incidence of 15%. Although tumours have distinct phenotypes they all exhibit ductular structures. Immunohistochemical analysis of these structures shows their acinar origin. These data, linking for the first time the development of pancreatic carcinogenesis in vivo to the expression of the CCK2 receptor, support a key role of the CCK2 receptor in the initiation of pancreatic cancer. Moreover, ElasCCK2 mice provide a model for carcinogenesis by transformation and dedifferentiation of acinar cells.

Expression of CCK2 receptors in the murine pancreas: proliferation, transdifferentiation of acinar cells, and neoplasia

BACKGROUND & AIMS

To explore the pancreatic function of CCK2/gastrin receptor, we created ElasCCK2 transgenic mice expressing the human receptor in pancreatic exocrine cells. In previous studies, the transgenic CCK2/gastrin receptor was demonstrated to mediate enzyme release and protein synthesis. We now report results of phenotypic and long-term studies.

METHODS

Pancreas was characterized using morphometry and immunohistochemistry. ElasCCK2 mice were crossed with INS-GAS mice expressing gastrin in pancreatic beta cells to achieve continuous stimulation of the CCK2/gastrin receptor.

RESULTS

The pancreatic weight of ElasCCK2 mice was increased by 40% and correlated with an increase in the area of exocrine tissue. Alterations in pancreatic histology were apparent from postnatal day 50. Crossing the ElasCCK2 mice with INS-GAS mice resulted in development of morphologic changes in younger animals. Malignant transformation occurred in 3 of 20 homozygous ElasCCK2 mice. Although tumors had different phenotypes, they all developed through an acinar-ductal carcinoma sequence.

CONCLUSIONS

Our data show that transgenic expression of a G protein-coupled receptor can lead to cancer. This study also supports a key role of the CCK2/gastrin receptor in the development of pre- and neoplastic lesions of the pancreas. ElasCCK2 mice provide a model for carcinogenesis by transformation and dedifferentiation of acinar cells.

Tsix-mediated repression of Xist accumulation is not sufficient for normal random X inactivation

During the X inactivation process, one X chromosome in each female embryonic cell is chosen at random to become coated by Xist RNA and silenced. Tsix, a transcript anti-sense to Xist, participates in the choice of the inactive X and in Xist regulation through as yet unknown mechanisms. Undifferentiated female ES cells, which have two active Xs, recapitulate random X inactivation when induced to differentiate. A 65 kb deletion targeted to one of the two Xs in a female ES cell line, and including both the end of the Xist gene and the site of initiation of Tsix, resulted in the exclusive inactivation of the deleted X in differentiated ES cells. We have re-examined the phenotype of the 65 kb deletion and targeted Tsix and the terminal exons of Xist back to the deleted locus using a cre/loxP site-specific re-insertion strategy. We show that prior to inactivation the deleted X is associated in undifferentiated ES cells with both increased Xist expression and diffusion of the Xist transcript away from its site of synthesis. Restoration of Tsix repressed the steady-state level of Xist expression and restricted Xist RNA to its transcription site. At the onset of inactivation in differentiated ES cells, restoration of Tsix failed to restore random X-inactivation, even though the levels of Xist RNA accumulation in cis were markedly reduced. These results identify for the first time a dual function for Tsix as both a repressor of the steady-state level of Xist expression and as a regulator of the distribution of Xist RNA within the nucleus. They also establish that random inactivation requires mechanisms additional to the in cis repression of XIST:

Genetics. Reprogramming X inactivation

Inactivation of one of the two X chromosomes occurs in all cells of female adult mice so that genes are expressed from only one X chromosome. In a Perspective, Clerc and Avner describe an elegant series of experiments in mouse embryos cloned from adult and embryonic female cell nuclei (Eggan et al.) that reveal how the inactivation state of the X chromosomes is reprogrammed.