Relationship Between Psychological Empowerment and Nurses' Job Satisfaction: A Systematic Review and Correlational Meta-Analysis

Psychological empowerment is a motivational concept that encompasses a person's thoughts and perceptions that give a sense of behavior and commitment to the work. Psychological empowerment is widely acknowledged to be associated with nurses' job satisfaction. However, this relationship has been found to be controversial. Therefore, this systematic review and meta-analysis aimed to investigate the relationship between psychological empowerment and nurses' job satisfaction. The electronic databases CINAHL, PubMed, Web of Science, and Google Scholar were utilized to search for relevant studies published from 2001 to 2024. The correlation coefficients were extracted for each eligible study and transformed into Fisher's Z. Then, the pooled effect size (r coefficient) was computed using Fisher's Z and the corresponding standard error. Moreover, I2 was used to assess the heterogeneity of studies. Begg's rank and Egger's test were employed to assess the publication bias. Sensitivity analysis was utilized to measure the robustness of study findings using the one-leave-out approach, and a critical appraisal tool for cross-sectional studies was adopted to assess the quality of included studies. A total of 18 studies were selected for analysis with a total sample of 6,353 nurses from different countries. The included studies ranged from moderate to high quality based on the quality assessment checklist. The pooled effect size for the correlation between psychological empowerment and nurses' job satisfaction was 0.512 (95% confidence interval = 0.406-0.604) with mild-to-moderate heterogeneity. Moreover, the majority of the studies confirmed a positive relationship between the two measured concepts. This study presents evidence indicating that psychological empowerment has a sensible relationship with nurses' job satisfaction. Therefore, nurse administrators should implement tailored strategies to trigger nurses' psychological empowerment, aiming to boost job satisfaction and reduce turnover and burnout. However, additional studies are essential to establish a causal relationship.

Correction: Krayem et al. The Benefit of Reactivating p53 under MAPK Inhibition on the Efficacy of Radiotherapy in Melanoma. Cancers 2019, 11, 1093

In the original article [...].

MA-QC: Free online software for prostate MR quality control and PI-QUAL assessment

PURPOSE

To validate MRI Analyzer Quality Control (MA-QC), a free and open-source online software designed to facilitate MR data acquisition quality control and PI-QUAL score calculation.

MATERIAL AND METHODS

MA-QC is a web-based software, designed for analysing DICOM data related to MR acquisition parameters. The software allows automatic extraction of 18 technical criteria, and manual input of 12 visual criteria, to calculate the PI-QUAL score. We collected 100 prostate MRI datasets from four MR device manufacturers to test data compatibility, automatic sequence recognition, and robustness of technical criteria extraction from DICOM data. The main issue was to determine the spatial resolution in the phase and frequency directions, due to variable encoding of the DICOM datasets.

RESULTS

Acquisition data could be extracted from all sample examinations (100%), with a median analysis speed of 15.2 ± 4.4 images per second and mean processing time of 96 [11-326] seconds per examination. MA-CQ automatically detected the optimal T2-w, DWI and DCE sequences in 71 out of 100 (71%) cases, and required manual selection of at least one sequence in 29 out of 100 (29%) cases to get the best parameters. Display of technical criteria for the 3 sequences was instantaneous. PI-QUAL score could be calculated in all cases.

CONCLUSION

This software brings substantial help in the quality assessment of prostate MRI examinations, by providing fast extraction of series data and the 18 technical parameters of PI-QUAL. PI-QUAL scoring can be performed in less than two minutes, helping to focus on the visual criteria, allowing use of this software in the clinical workflow in the aim of improving overall image quality in prostate MR imaging.

The benefit of co-targeting PARP-1 and c-Met on the efficacy of radiotherapy in wild type BRAF melanoma

Melanoma is known to be a radioresistant cancer. Melanoma radioresistance can be due to several factors such as pigmentation, antioxidant defenses and high Deoxyribonucleic acid (DNA) repair efficacy. However, irradiation induces intracellular translocation of RTKs, including cMet, which regulates response to DNA damage activating proteins and promotes DNA repair. Accordingly, we hypothesized that co-targeting DNA repair (PARP-1) and relevant activated RTKs, c-Met in particular, may radiosensitize wild-type B-Raf Proto-Oncogene, Serine/Threonine Kinase (WTBRAF) melanomas where RTKs are often upregulated. Firstly, we found that PARP-1 is highly expressed in melanoma cell lines. PARP-1 inhibition by Olaparib or its KO mediates melanoma cell sensitivity to radiotherapy (RT). Similarly, specific inhibition of c-Met by Crizotinib or its KO radiosensitizes the melanoma cell lines. Mechanistically, we show that RT causes c-Met nuclear translocation to interact with PARP-1 promoting its activity. This can be reversed by c-Met inhibition. Accordingly, RT associated with the inhibition of both c-Met and PARP-1 resulted in a synergistic effect not only on tumor growth inhibition but also on tumor regrowth control in all animals following the stop of the treatment. We thus show that combining PARP and c-Met inhibition with RT appears a promising therapeutic approach in WTBRAF melanoma.

Tyrosine-Dependent Phenotype Switching Occurs Early in Many Primary Melanoma Cultures Limiting Their Translational Value

The use of patient-derived primary cell cultures in cancer preclinical assays, including drug screens and genotoxic studies, has increased in recent years. However, their translational value is constrained by several limitations, including variability that can be caused by the culture conditions. Here, we show that the medium composition commonly used to propagate primary melanoma cultures has limited their representability of their tumor of origin and their cellular plasticity, and modified their sensitivity to therapy. Indeed, we established and compared cultures from different melanoma patients propagated in parallel in low-tyrosine (Ham's F10) or in high-tyrosine (Ham's F10 supplemented with tyrosine or RPMI1640 or DMEM) media. Tyrosine is the precursor of melanin biosynthesis, a process particularly active in differentiated melanocytes and melanoma cells. Unexpectedly, we found that the high tyrosine concentrations promoted an early phenotypic drift towards either a mesenchymal-like or senescence-like phenotype, and prevented the establishment of cultures of melanoma cells harboring differentiated features, which we show are frequently present in human clinical biopsies. Moreover, the invasive phenotype emerging in these culture conditions appeared irreversible and, as expected, associated with intrinsic resistance to MAPKi. In sharp contrast, differentiated melanoma cell cultures retained their phenotypes upon propagation in low-tyrosine medium, and importantly their phenotypic plasticity, a key hallmark of melanoma cells. Altogether, our findings underline the importance of culturing melanoma cells in low-tyrosine-containing medium in order to preserve their phenotypic identity of origin and cellular plasticity.

Clinical outcomes with drug-eluting stents, bare-metal stents, and bioresorbable scaffolds implanted in patients with AMI treated with primary PCI. Data from the Prague-18 trial

Background

Drug-eluting stents (DESs) are the recommended choice of stents for primary PCI.

Purpose/Methods

The study aimed to determine why interventional cardiologists used non-DESs and how they had influenced the patient prognosis. The efficacy and safety outcomes of the different stents were also compared in treated with either prasugrel or ticagrelor.

Results

Of the PRAGUE 18 study patients, 749 (67.4%) were treated with DESs, 296 (26.6%) with BMS, and 66 (5.9%) with BVS. Cardiogenic shock at presentation and the left main disease, especially as culprit lesion, and right coronary artery stenosis were the reasons for BMS selection.

The incidence of the primary net-clinical EP (CV death, nonfatal MI, stroke, major bleeding, or revascularization) at 7 days was 2.6% vs. 6.5%, and 3.0% in the DESs, BMSs, and BVSs, respectively (HR 2.7; 95% CI 1.419–5.15, P=0.002 for BMS vs. DES and 1.25 (0.29–5.39) for BVS vs. DES, P=0.76). Patients with BMSs were at higher risk of death at 30 days (HR 2.20; 95% CI 1.01–4.76; for BMS vs. DES, P=0.045), and at one year (HR 2.1; 95% CI 1.19–3.69; P=0.01); they also had higher composite of cardiac death, re-MI and stroke (HR 1.66; 95% CI 1.0–2.74; P=0.047) at one year. BMSs were associated with significantly higher rate of primary EPs either treated with prasugrel or ticagrelor.

Conclusion

Patients with the highest risk profile were preferably treated with BMS the contrary to BVS. BMSs were associated with a significantly higher rate of cardiovascular events either treated with prasugrel or ticagrelor.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Charles University Cardiovascular Research Program P-35 and Q-38, Charles University, Czech Republic

RTK Inhibitors in Melanoma: From Bench to Bedside

MAPK (mitogen activated protein kinase) and PI3K/AKT (Phosphatidylinositol-3-Kinase and Protein Kinase B) pathways play a key role in melanoma progression and metastasis that are regulated by receptor tyrosine kinases (RTKs). Although RTKs are mutated in a small percentage of melanomas, several receptors were found up regulated/altered in various stages of melanoma initiation, progression, or metastasis. Targeting RTKs remains a significant challenge in melanoma, due to their variable expression across different melanoma stages of progression and among melanoma subtypes that consequently affect response to treatment and disease progression. In this review, we discuss in details the activation mechanism of several key RTKs: type III: c-KIT (mast/stem cell growth factor receptor); type I: EGFR (Epidermal growth factor receptor); type VIII: HGFR (hepatocyte growth factor receptor); type V: VEGFR (Vascular endothelial growth factor), structure variants, the function of their structural domains, and their alteration and its association with melanoma initiation and progression. Furthermore, several RTK inhibitors targeting the same receptor were tested alone or in combination with other therapies, yielding variable responses among different melanoma groups. Here, we classified RTK inhibitors by families and summarized all tested drugs in melanoma indicating the rationale behind the use of these drugs in each melanoma subgroups from preclinical studies to clinical trials with a specific focus on their purpose of treatment, resulted effect, and outcomes.

Dasatinib Stimulates Its Own Mechanism of Resistance by Activating a CRTC3/MITF/Bcl-2 Pathway in Melanoma with Mutant or Amplified c-Kit

Amplification or activating mutations of c-Kit are a frequent oncogenic alteration, which occurs commonly in acral and mucosal melanoma. Among c-Kit inhibitors, dasatinib is the most active due to its ability to bind both active and inactive conformations of the receptor. However, its use as a single agent in melanoma showed limited clinical benefit. We first found that sensitivity to dasatinib is restricted to melanoma cell lines harboring c-Kit alteration but, unexpectedly, we observed lower effect at higher concentrations that can readily be found in patient blood. We then investigated relevant pathway alterations and found complete inhibition of MAPK and PI3K/AKT pathways but an increase in MITF and its downstream target Bcl-2 through CRTC3 pathway, which turn on the CREB regulated transcription of MITF. More importantly, dasatinib upregulates MITF and Bcl-2 through SIK2 inhibition revealed by CRTC3 reduced phosphorylation, CREB transcription activation of MITF, MITF transcription activation of Bcl-2 as well as pigmentation. Furthermore, overexpression of MITF renders melanoma cells resistant to all dasatinib concentrations. Selective Bcl-2 inhibition by ABT-199 or Bcl-2 knockout restores the sensitivity of melanoma cells to dasatinib, validating the involvement of MITF and Bcl-2 axis in the resistance of melanoma to dasatinib. In conclusion, we showed for the first time that dasatinib in melanoma stimulates its proper mechanism of resistance, independently of MAPK and PI3K/AKT pathways reactivation commonly associated to secondary c-Kit mutations, but through CRTC3/MITF/Bcl-2 pathway activation at clinically relevant doses which may explain the weak clinical benefit of dasatinib in patients with melanoma. IMPLICATIONS: Dasatinib stimulates its proper mechanism of resistance through CRTC3/MITF/Bcl-2 pathway, which may explain its modest clinical efficiency in patients with melanoma.

Infarct size following loading with ticagrelor/prasugrel versus clopidogrel in ST-segment elevation myocardial infarction

Background

Treatment with newer direct-acting anti-platelet drugs (Ticagrelor and Prasugrel) prior to primary percutaneous coronary intervention (PCI) is associated with improved clinical outcome in patients with ST-segment elevation myocardial infarction (STEMI) when compared with Clopidogrel.

Purpose

We retrospectively compared infarct size following non-randomized treatment with

Ticagrelor/Prasugrel versus Clopidogrel in a population of STEMI patients treated with primary PCI.

Methods

Patients were loaded with Clopidogrel, Ticagrelor or Prasugrel in the ambulance before primary PCI. Infarct size and myocardial salvage index were calculated using cardiac magnetic resonance (CMR) during index admission and at three-month follow-up.

Results

693 patients were included in this analysis. Clopidogrel was given to 351 patients and Ticagrelor/Prasugrel to 342 patients. The groups were generally comparable in terms of baseline and procedural characteristics. Median infarct size at three-month follow-up was 12.9% vs 10.0%, in patients treated with Clopidogrel and Ticagrelor/ Prasugrel respectively (p<0.001), and myocardial salvage index was 66% vs 71% (p<0.001). Results remained significant in a multiple regression model (p<0.001).

Conclusion

Pre-hospital loading with Ticagrelor or Prasugrel compared to Clopidogrel, was associated with smaller infarct size and larger myocardial salvage index at three-month follow-up in patients with STEMI treated with primary PCI.

Infarct size at three month follow-up

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): The Novo Nordisk Foundation. The Alfred Benzon Foundatioun.

Twenty-year survival of patients with atherosclerotic non-obstructive coronary plaques

Background

Atherosclerotic non-obstructive coronary artery disease (NObCAD) is frequently observed in patients referred for coronary angiography. No available data exist for the long-term prognosis of NObCAD patients beyond 10 years.

Purpose

We sought to compare the 15- and 20-year survival among patients presenting with chronic stable angina who had smooth coronary vessels, NobCAD, and obstructive (ObCAD), on invasive coronary angiography.

Methods

Coronary angiography of 671 consecutive patients presented with suspected CAD were retrospectively evaluated from single center registry between January and December 1998 and linked to administrative databases for outcomes evaluation. No CAD, NobCAD, and ObCAD were defined as 0%, 1% to 49%, and ≥50% luminal narrowing in epicardial coronary artery, respectively. The 15- and the 20-year survival rates were compared by Kaplan-Meier curve and multivariate Cox proportional hazards regression was used to identify significant independent predictors of mortality.

Results

Of 613 individuals (78.7% men with median age of 55.6 (51.0–65.2) years), 74 (12.1%) had normal coronary arteries, 42 (6.9%) had NobCAD, and 497 (81%) had ObCAD. The 15- and the 20-year survival rates were 89%, 66.7%, 62.4% and 79.7%, 54.7%, 42,5% in patients with normal, NobCAD, and ObCAD, respectively, (P=0.050 for no versus NobCAD; P=0.001 for no versus ObCAD at 20-year), These angiographic severity categories showed a strong gradient (P<0.001) (Figure 1). At 15-year follow-up, both ObCAD (adjusted HR=2.42, 95% CI (1.21–4.85), p=0.013) and NobCAD patients (HR=2.65, 95% CI (1.15–6.11), p=0.023) showed higher mortality compared to no CAD group. Independent predictors of mortality were, obstructive CAD (HR=2.34, 95% CI (1.407–3.916), P=0.001 for no versus NobCAD; HR=1.93, 95% CI (1.0–3.72), P=0.050, for no versus obstructive CAD), and age at addmission (HR=1.06, 95% CI (1.04–1.07), P<0.001).

Conclusion

The result of this analysis highlighted the less benign course of NobCAD that carries a mortality risk similar to patients with ObCAD at 15-and at 20-year follow-up. These findings support the need for aggressive anti-atherosclerotic drug therapy in such individuals and underscore the necessary efforts to improve the risk stratification and management of patients with non-obstructive CAD.

Funding Acknowledgement

Type of funding source: None

FGF2 Induces Resistance to Nilotinib through MAPK Pathway Activation in KIT Mutated Melanoma

KIT is a bona fide oncogene in a subset of melanoma and, ex vivo, KIT inhibitors are very efficient at killing KIT-mutant melanoma cell lines. However, KIT-mutant melanoma tumors tend to show a de novo resistance in most cases and a limited duration of response when response is achieved. We performed pharmacodynamic studies on patients with KIT-mutated melanoma treated with nilotinib, which suggested that the FGF2 axis may be a mechanism of resistance in this subset of melanoma. Using several melanoma cell lines, which are dependent on oncogenic KIT, we showed that although KIT inhibition markedly decreased cell viability in melanoma cell lines with distinct KIT mutations, this effect was lessened in the presence of FGF2 due to inhibition of BIM expression by MAPK pathway activation. Addition of a MEK inhibitor reversed the FGF2-driven resistance for all KIT mutants. We confirmed the expression of FGF2 and activation of MEK-ERK in melanoma patients using in situ data from a clinical trial. Therefore, the combined inhibition of KIT with FGFR or MEK may be a next-step effective clinical strategy in KIT-mutant melanoma.

Kinome Profiling to Predict Sensitivity to MAPK Inhibition in Melanoma and to Provide New Insights into Intrinsic and Acquired Mechanism of Resistance

Mitogen-activated protein kinase (MAPK) inhibition with the combination of BRAF (Rapidly Accelerated Fibrosarcoma) and MEK (Mitogen-activated protein kinase kinase) inhibitors has become the standard of first-line therapy of metastatic melanoma harbouring BRAF V600 mutations. However, about half of the patients present with primary resistance while the remaining develop secondary resistance under prolonged treatment. Thus, there is a need for predictive biomarkers for sensitivity and/or resistance to further refine the patient population likely to benefit from MAPK inhibitors. In this study, we explored a top-down approach using a multiplex kinase assay, first, to discover a kinome signature predicting sensitivity, intrinsic and acquired resistance to MAPK inhibitors in melanoma, and second, to understand the mechanism of resistance using cell lines. Pre-dose tissues from patients (four responders and three non-responders to BRAFi monotherapy) were profiled for phosphotyrosine kinase (PTK) and serine-threonine kinase (STK) activities on a PamChip^® peptide microarray in the presence and absence of ex vivo BRAFi. In addition, molecular studies were conducted on four sensitive parental lines, their offspring with acquired resistance to BRAFi and two lines with intrinsic resistance. PTK and STK activities in cell lysates were measured in the presence and absence of ex vivo BRAFi and/or MEKi. In tissue lysates, concentration-dependent ex vivo inhibition of STK and PTK activities with dabrafenib was stronger in responders than in non-responders. This difference was confirmed in cell lines comparing sensitive and resistant ones. Interestingly, common features of resistance were increased activity of receptor tyrosine kinases, Proto-oncogene tyrosine-protein kinase Src (Src) family kinases and protein kinase B (PKB, AKT) signalling. These latter results were confirmed by Western blots. While dabrafenib alone showed an inhibition of STK and PTK activities in both tissues and cell lines, the combination of dabrafenib and trametinib showed an antagonism on the STK activities and a synergism on PTK activities, resulting in stronger inhibitions of overall tyrosine kinase activities. Altogether; these data reveal that resistance of tumours and cell lines to MAPK inhibitors can be predicted using a multiplex kinase assay and is associated with an increase in specific tyrosine kinase activities and globally to AKT signalling in the patient’s tissue. Thus, such a predictive kinome signature would help to identify patients with innate resistance to MAPK double inhibition in order to propose other therapies.

The Benefit of Reactivating p53 under MAPK Inhibition on the Efficacy of Radiotherapy in Melanoma

Radiotherapy (RT) in patients with melanoma historically showed suboptimal results, because the disease is often radioresistant due to various mechanisms such as scavenging free radicals by thiols, pigmentary machinery, or enhanced DNA repair. However, radiotherapy has been utilized as adjuvant therapy after the complete excision of primary melanoma and lymph nodes to reduce the rate of nodal recurrences in high-risk patients. The resistance of melanoma cells to radiotherapy may also be in relation with the constitutive activation of the MAPK pathway and/or with the inactivation of p53 observed in about 90% of melanomas. In this study, we aimed to assess the potential benefit of adding RT to BRAF-mutated melanoma cells under a combined p53 reactivation and MAPK inhibition in vitro and in a preclinical animal model. We found that the combination of BRAF inhibition (vemurafenib, which completely shuts down the MAPK pathway), together with p53 reactivation (PRIMA-1Met) significantly enhanced the radiosensitivity of BRAF-mutant melanoma cells. This was accompanied by an increase in both p53 expression and activity. Of note, we found that radiation alone markedly promoted both ERK and AKT phosphorylation, thus contributing to radioresistance. The combination of vemurafenib and PRIMA-1Met caused the inactivation of both MAPK kinase and PI3K/AKT pathways. Furthermore, when combined with radiotherapy, it was able to significantly enhance melanoma cell radiosensitivity. Interestingly, in nude mice bearing melanoma xenografts, the latter triple combination had not only a synergistic effect on tumor growth inhibition, but also a potent control on tumor regrowth in all animals after finishing the triple combination therapy. RT alone had only a weak effect. In conclusion, we provide a basis for a strategy that may overcome the radioresistance of BRAF-mutated melanoma cells to radiotherapy. Whether this will translate into a rational to use radiotherapy in the curative setting in BRAF-mutated melanoma patients deserves consideration.

ICSI outcomes using testicular spermatozoa in non-azoospermic couples with recurrent ICSI failure and no previous live births

BACKGROUND

The use of testicular over ejaculated spermatozoa for ICSI has been presented as an alternative to overcome infertility in men with poor semen parameters or high levels of sperm DNA fragmentation.

OBJECTIVE

To evaluate the efficacy of testicular ICSI outcomes in couples with no previous live birth and recurrent ICSI failure using ejaculated spermatozoa by comparison to the outcomes of couples with similar history of recurrent ICSI using ejaculated spermatozoa only.

MATERIALS AND METHODS

A total of 145 couples undergoing ejaculated or testicular ICSI cycles with no previous live births and with at least two previous failed ICSI cycles with ejaculated spermatozoa were evaluated retrospectively. ICSI was performed either with ejaculated (E-ICSI) or with testicular (T-ICSI) spermatozoa. Semen parameters and sperm DNA quality were assessed prior to the oocyte collection day. Primary outcomes included cumulative live birth and pregnancy rates. Secondary analysis included percentage of DNA fragmentation in ejaculated spermatozoa (SCSA^® and TUNEL).

RESULTS

Patients undergoing T-ICSI (n = 77) had a significantly higher clinical pregnancy rate/fresh embryo transfer (ET) (27.9%; 17/61) and cumulative live birth rate (23.4%; 15/64) compared to patients using E-ICSI (n = 68) (clinical pregnancy rate/fresh ET: 10%; 6/60 and cumulative live birth rate: 11.4%; 7/61). Further, T-ICSI yield significantly better cumulative live birth rates than E-ICSI for men with high TUNEL (≥36%) (T-ICSI: 20%; 3/15 vs. E-ICSI: 0%; 0/7, p < 0.025), high SCSA^® (≥25%) scores (T-ICSI: 21.7%; 5/23 vs. E-ICSI: 9.1%; 1/11, p < 0.01), or abnormal semen parameters (T-ICSI: 28%; 7/25 vs. E-ICSI: 6.7%; 1/15, p < 0.01).

CONCLUSIONS

The use of testicular spermatozoa for ICSI in non-azoospermic couples with no previous live births, recurrent ICSI failure, and high sperm DNA fragmentation yields significantly better live birth outcomes than a separate cohort of couples with similar history of ICSI failure entering a new ICSI cycle with ejaculated spermatozoa.

Abstract P6-07-05: Interactions between adipocyte stem cells and normal or tumoral mammary epithelial cells. Potantial role of BRCA status and estrogen pathway

Prophylactic mastectomies are more and more frequent. As a result, breast reconstruction is also more frequent and mammary lipofilling often used to improve the aesthetic results. Contradictory cliniacal data have been published concerning the risk of breast cancer after using this technique. It is possible that Adipose-Derived Stem / Stromal Cells (ADSC or ASC), present in the lipofilling may interact with normal or tumoral epithelial mammary cells.

In this context, we studied the effect of conditioned media of human ASC on different tumor breast lines (MCF7, T47D, ZR75-1, SKBR3, SUM159). The ASCs were extracted from non-cancer patients with identical body mass index (BRCA1 and BRCA2 mutated or wild-type).

We observed that the conditioned media of ASC induced the proliferation of luminal, Her2 and basal-like tumor breast lines. This proliferative effect is more important when ASCs are differentiated and the BRCA mutation status has no impact on it. Finally, we have demonstrated an estrogen signaling within the ASCs which is set up during their differentiation. Differentiated ASCs express ERα and produce 17β-estradiol (E2). This estrogenic pathway seems to be established independently of the BRCA mutational status. The proliferative effect on luminal mammary lines induced by conditioned media of ASC could pass through this estrogenic signaling, but remains to be confirmed.

These data highlight the fact that adipose-derived stem cells in mammary lipofilling should only be used after a cancer has been eliminated, as there are still some uncertainties concerning their implication on carcinogenesis.

Citation Format: Benderra M-A, Zaoui M, Atlan M, Ferrand N, Denis JA, Leban M, Lamari F, Larsen AK, Sabbah M, Gligorov J. Interactions between adipocyte stem cells and normal or tumoral mammary epithelial cells. Potantial role of BRCA status and estrogen pathway [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-07-05.

B-ind1, a novel mediator of Rac1 signaling cloned from sodium butyrate-treated fibroblasts

Sodium butyrate is a multifunctional agent known to inhibit cell proliferation and to induce differentiation by modulating transcription. We have performed differential display analysis to identify transcriptional targets of sodium butyrate in Balb/c BP-A31 mouse fibroblasts. A novel butyrate-induced transcript B-ind1 has been cloned by this approach. The human homologue of this transcript contains an open reading frame that codes for a protein of 370 amino acids without known functional motifs. In transfected cells, the B-ind1 protein has been found to potentiate different effects of the small GTPase Rac1, such as c-Jun N-terminal kinase activation and transcriptional activity of nuclear factor kappaB (NF-kappaB). In addition, we have demonstrated that B-ind1 forms complexes with the constitutively activated Rac1 protein. To investigate the role of B-ind1 in Rac1 signaling, we have constructed several deletion mutants of B-ind1 and tested their ability to affect the activation of NF-kappaB by Rac1. Interestingly, the fragment encoding the median region of human B-ind1 acted as a dominant-negative variant to block Rac1-mediated NF-kappaB activity. These data define B-ind1 as a novel component of Rac1-signaling pathways leading to the modulation of gene expression.

Estrogen induction of the cyclin D1 promoter: involvement of a cAMP response-like element

Estrogens induce cell proliferation in target tissues by stimulating progression through the G(1) phase of the cell cycle. Induction of cyclin D1 expression is a critical feature of the mitogenic action of estrogen. We have determined a region between -96 and -29 in the cyclin D1 promoter that confers regulation by estrogens in the human mammary carcinoma cells MCF-7. This region encompasses a unique known transcription factor binding site with a sequence of a potential cAMP response element (CRE-D1). The induction is strictly hormone dependent and requires the DNA binding domain as well as both AF-1 and AF-2 domains of the estrogen receptor (ER) alpha. Destruction of the CRE-D1 motif caused complete loss of estrogen responsiveness. Both c-Jun and ATF-2 transactivated the cyclin D1 promoter in transient transfection experiments, and a clear additional increase was detected when ER was cotransfected with either c-Jun or with c-Jun and ATF-2 but not with ATF-2 alone. Furthermore, the expression of a dominant negative variant of c-Jun, TAM67, completely abolished the induction of the cyclin D1 promoter both in the absence and presence of ER. We show that ATF-2 homodimers and ATF-2/c-Jun heterodimers, but not c-Jun homodimers, were able to bind the CRE of the cyclin D1 promoter. To interpret these results, we propose a mechanism in which ATF-2/c-Jun heterodimers bind to the CRE-D1 element and mediate the activation of cyclin D1 promoter by the ER. This mechanism represents a pathway by which estrogens control the proliferation of target cells.

Oestrogen receptor facilitates the formation of preinitiation complex assembly: involvement of the general transcription factor TFIIB

The action of oestrogen hormones is mediated through the oestrogen receptor (ER), a member of a large superfamily of nuclear receptors that function as ligand-activated transcription factors. Sequence-specific transcription factors, including the nuclear receptor superfamily, are thought to interact either directly or indirectly with general transcription factors to regulate transcription. Although numerous studies have focused on the identification of potential co-activators interacting with isolated trans-activation domains of ER, few have investigated the mechanisms by which ER transmits its signal to the basal transcription machinery. We show that ER does not stabilize the binding of the TATA-box binding protein (TBP) of the TFIID complex, or of TFIIB to the promoter, although a stable ER-TBP-TFIIB-promoter complex was detected, suggesting that ER, TBP and TFIIB might interact with each other to form a complex to the promoter. We also demonstrate that ER binds specifically to TFIIB, a key component of the preinitiation complex. Affinity chromatography with immobilized deletion mutants of ER maps a TFIIB interaction region that encompasses the DNA-binding domain. The addition of excess TFIIB to transcription reactions in vitro did not, however, affect the magnitude of transcriptional activation by ER. These results indicate that, in contrast with current models, ER does not activate transcription by increasing the rate of assembly of TFIIB into the transcription complex. An increased concentration of TFIIB was unable, by itself, to overcome the requirement for ER. By using an immobilized promoter-template assay employing nuclear extract from HeLa cells, recombinant human ER increased the stable association of subsequent components of the transcription machinery (TFIIE and TFIIF), in correlation with ER-induced transcription. Our results suggest that ER acts, in an early step, during or immediately after the formation of template-committed complexes containing TFIIB, favouring the recruitment of one or more components of the basic transcription machinery as well as co-activators.

Properties of overlapping EREs: synergistic activation of transcription and cooperative binding of ER

We have designed a novel estrogen-responsive unit, overERE, which consists of two overlapping ERE separated by 5 bp (center-to-center). In gel retardation assays, this sequence forms a low-mobility complex that migrates like an estrogen receptor tetramer. The receptor-overERE complex was specific and was supershifted by anti-ER H222 antibodies. Dose response studies showed that the formation of the receptor tetramer-overERE complex was cooperative. Truncated receptors were used to assess the contribution of the receptor domains. Deletion of the E domain of the ER prevented the formation of an ER-tetramer complex, which reflects a novel function of this receptor domain. In transfection experiments, 17-beta-estradiol activated transcription from an overERE-containing promoter 4-6 times better than from an ERE-containing promoter. This synergistic effect was observed using either the natural hormone (17-beta-estradiol) or xenoestrogens (phenol red, chlordane). We conclude that two overlapping estrogen-responsive elements can elicit synergistic induction of transcription.

Direct inhibition of the expression of cyclin D1 gene by sodium butyrate

In the mouse fibroblasts BP-A31 as well as in the human epidermoid carcinoma cells KB-3-1, both cyclin D1 mRNA and protein contents decreased rapidly during incubation with sodium butyrate. The decrease of cyclin D1 mRNA was not prevented by cycloheximide indicating that protein synthesis is not required for the inhibition of the expression of cyclin D1 gene by sodium butyrate. The 973 bp region upstream of the human cyclin D1 gene conferred inhibition of the expression of an indicator gene in transiently transfected cells. An 11 base-pair segment situated within this region, with a strong homology to the butyrate-response consensus element identified in butyrate-inducible promoters, also caused an inhibition of transcription under these conditions, indicating that cyclin D1 expression is inhibited by butyrate at the transcriptional level.

Characterization of insulin-like growth factor binding proteins and regulation of IGFBP3 in human mesangial cells

IGF-I regulates renal growth and development. Insulin-like growth factor binding proteins (IGFBPs) are synthesized by the kidney and may modulate the local autocrine and/or paracrine actions of IGF-I. We have previously demonstrated that mesangial cells (MC) release IGF-I and IGF-binding activity; however, the specific IGFBPs produced by these cells and the factors involved in their regulation are unknown. We examined MC for expression of IGFBP-1 to -6 mRNAs and proteins. RNase protection assays using total RNA demonstrated that MC express all of the IGFBPs. [125I]IGF-I Western ligand blot of conditioned medium demonstrated that MC release IGFBPs of 24, 29, 32 kDa, and a doublet at 46 kDa, consistent with IGFBP-4, -5, -2 and -3, respectively. IGFBP species of 28 and 34 kDa were also detected. Since IGF-I and TGF-beta are implicated in glomerular hypertrophy and matrix expansion, we tested their effect on IGFBPs released by MC. IGF-I (100 ng/ml), TGF-beta (2 ng/ml) and forskolin (10(-5) M) differentially regulated the abundance of IGFBPs released in the conditioned medium in a time-dependent manner. IGF-I and TGF-beta were potent inducers of the release of IGFBP3 protein; however, TGF-beta, but not IGF-I, increased IGFBP3 mRNA levels. Recombinant IGFBP3 was tested for its effect on IGF-I-induced mitogenesis. IGFBP3 inhibited IGF-I-stimulated DNA synthesis in a dose-dependent manner with a peak effect observed at 50 nM IGFBP3. Although TGF-beta is a potent inhibitor of IGF-I-stimulated DNA synthesis, this effect is not mediated via IGFBPs. Expression of IGFBP-1 to -6 by MC suggests that these proteins may modulate IGF-I bioavailability in the glomerulus. IGF-I itself, TGF-beta and cAMP agonists may indirectly modulate the effects of IGF-I via the release of IGFBPs by MC.

The 90 kDa heat-shock protein (hsp90) modulates the binding of the oestrogen receptor to its cognate DNA

The role of heat-shock protein 90 (hsp90) in the regulation of the oestrogen receptor (ER) function is less well understood than for other steroid-hormone receptors because hsp90 is not involved in the stabilization or induction of a high-affinity ligand-binding state of ER nor in the inhibition of receptor dimerization. Electrophoretic mobility-shift assays, using purified ER and hsp90, were employed to investigate directly the effect of hsp90 on the ability of ER to bind to the oestrogen-response element (ERE) from the vitellogenin A2 gene. Contrary to models in which hsp90 binds to and passively inactivates steroid-hormone receptors, our studies show that the binding of ER to ERE is inversely dependent on the relative concentration of hsp90. Exposure of purified ER-hsp90 complexes to ERE led to the dissociation of hsp90 and concomitant specific binding of ER to ERE. We demonstrate that the amount of ER-ERE complex decreased with increasing concentrations of hsp90. Furthermore hsp90 dissociated preformed high-affinity ER-ERE complexes. Kinetic dissociation experiments indicate the hsp90 acts in a dynamic and specific process rather than by simple trapping of ER owing to its inherent off-rate. The receptor released from the ERE-bound state by hsp90 was recovered associated with hsp90 and was able to rebind to ERE. These results indicate that hsp90 does not suppress ER function merely by steric hindrance. On the basis of these results and others, we propose that, in vivo, hsp90 may play a dual role in ER function: (i) at a physiological temperature, hsp90 stabilizes an active form of the receptor in accordance with its general molecular chaperone role; (ii) at elevated temperatures or under other environmental stress, the increased cellular concentration of hsp90 negatively interferes with ER-dependent transcription, in accordance with the inhibition of gene transcription attributed to hsp90 after heat shock.

Tyrosine phosphorylation of the erythropoietin receptor: role for differentiation and mitogenic signal transduction

The erythropoietin (Epo) receptor belongs to the cytokine receptor superfamily. Although the cytokine receptors do not possess a tyrosine kinase consensus sequence in the intracellular domain, rapid stimulation of a tyrosine kinase activity occurs after activation by the ligand. We and others have shown that Epo induces the tyrosine phosphorylation of its cognate receptor as well as phosphorylation of other proteins. In this report, we examined the role of the receptor tyrosine residues in signal transduction. Eight tyrosine residues are located within the intracellular domain of the murine Epo receptor. A single tyrosine residue is present in the region previously shown to be sufficient for proliferative signal transduction. This tyrosine (Tyr 343) was mutated to phenylalanine. Moreover, mutant receptors were also generated with either a tyrosine residue or a phenylalanine residue at position 343 and with a COOH terminal truncation that removed the 7 other tyrosine residues. Expression vectors carrying these mutated receptors were transfected into the interleukin-3-dependent murine cell line Ba/F3. Epo-induced growth was sustained efficiently by all these receptors, although receptors without any tyrosine residues conferred a significantly reduced mitogenic activity. Moreover, all receptors were able to mediate Epo-dependant accumulation of beta-globin mRNA. The mutated receptors all induced the tyrosine phosphorylation of several cellular proteins after Epo stimulation. However, the truncated receptors induced the phosphorylation of a reduced number of proteins, suggesting that phosphorylated tyrosines of the receptor could have a role in the recruitment either of a tyrosine kinase or of tyrosine kinase substrate proteins. The receptors were all able to mediate Epo-induced activation of phosphatidylinositol 3-kinase, although truncated receptors no longer bound phosphatidylinositol 3-kinase.

Erythropoietin induces the association of phosphatidylinositol 3'-kinase with a tyrosine-phosphorylated protein complex containing the erythropoietin receptor

Stimulation of sensitive cells with erythropoietin results in rapid induction of protein tyrosine phosphorylation. Other than tyrosine phosphorylation of one chain of the erythropoietin receptor, the identities of the remaining tyrosine-phosphorylated proteins are undefined. In this report, we demonstrate that the stimulation of the erythropoietin-sensitive human UT7 cells by erythropoietin rapidly resulted in the appearance of phosphatidylinositol 3-kinase activity in anti-phosphotyrosine immunoprecipitates. Erythropoietin action was rapid, detectable after as early as 1 min stimulation, transient, returning to control level after 30 min stimulation and was observed using the erythropoietin concentrations able to stimulate the cell proliferation. Anti-(phosphatidylinositol 3-kinase) antibodies specifically immunoprecipitated 125I-erythropoietin bound to its receptor, strongly suggesting that phosphatidylinositol 3-kinase associated with a protein complex containing the activated erythropoietin receptor. To confirm this result, phosphatidylinositol 3-kinase was immunoprecipitated from erythropoietin-stimulated cells using mild conditions followed by Western analysis using anti-phosphotyrosine antibodies. Five tyrosine phosphorylated proteins were revealed: the cloned chain of the erythropoietin receptor, the regulatory subunit of phosphatidylinositol 3-kinase and three unidentified proteins of 111, 97 and 64 kDa. None of these tyrosine phosphorylated proteins was detected in anti-(phosphatidylinositol 3-kinase) immunoprecipitates from unstimulated cells. Thus, our results show that phosphatidylinositol 3-kinase associates with a tyrosine-phosphorylated protein complex containing the activated erythropoietin receptor.

Estrogen receptor-induced bending of the Xenopus vitellogenin A2 gene hormone response element

DNA bending is increasingly proposed as an essential step for the establishment of the multiprotein complexes required for transcription initiation. Polyamines and metallic cations, known to promote DNA-bending, enhance the binding of purified estrogen receptor (ER) to the estrogen response element (ERE) of the Xenopus vitellogenin A2 gene. Using both circular permutation electrophoretic mobility and cyclization assays, we provide evidence that ER bends the DNA at the estrogen response element. The same bending occurs as a result of estrogen receptor protein binding independently of its conformational changes induced by hormone or anti-hormone. We suggest a role of the observed DNA bending in estrogen-regulated transcription.

[Volvulus of the sigmoid colon. Emergency resection and anastomosis]

Eleven cases of sigmoid volvulus in patients aged 76 years in average, without visible signs of necrosis on endoscopy, are reported. All patients were treated within 6 to 48 hours by colic resection and immediate restoration of continuity with a mechanical anastomosis. Morbidity was low, including one case of evisceration and one of pneumonia, and there was no mortality after three months. Early resection seems to prevent the risks of necrosis and recurrence, and to have a good prognosis for survival.

Role of chromatin structure in transcriptional regulation of MMTV LTR hormone-dependent promoter

Studies of chromatin structure were performed in mouse fibroblast cell lines containing Bovine Papilloma Virus (BPV) based artificial minichromosomes containing Mouse Mammary Tumor Virus (MMTV) Long Terminal Repeat (LTR), a retroviral promoter regulated by glucocorticoids, driving the transcription of v-Ha-ras. These minichromosomes fractionate with the "active chromatin", indicating an association of the minichromosomes with components of the "nuclear matrix". Two regions of the minichromosomes upstream and downstream of v-Ha-ras are involved in this interaction. MMTV LTR promoter is associated with nucleosomes precisely positioned on the DNA sequences. Hormonal activation is accompanied by a structural change of the nucleosome associated with the hormone response elements (HREs). This structural change can be visualized by the appearance of a hormono-dependent DNaseI hypersensitive site. Anti-hormones, even when able to promote a strong binding of the receptor to the nucleus, are unable to induce the chromatin structural change. The strong association of the hormone-receptor complex with the nucleus is necessary to induce the DNaseI hypersensitive site and to maintain the transcription, but is not necessary for DNaseI hypersensitivity maintenance. This suggests a double role for the hormone-receptor complex: 1) induction of a chromatin rearrangement and 2) transcriptional transactivation.

Subunit composition of the estrogen receptor. Involvement of the hormone-binding domain in the dimeric state

The purified estrogen receptor (ER) whether in 9 or 5 S molecular form, binds more than one molecule of the monoclonal antibody JS 34/32 (Redeuilh, G., Moncharmont, B., Secco, C., and Baulieu, E.-E. (1987) J. Biol. Chem. 262, 6969-6975). We now have investigated the effects of controlled trypsin proteolysis and of a dissociating chaotropic salt (NaSCN) on the structure of the estrogen receptor covalently labeled with radioactive tamoxifen aziridine. When the DNA-binding transformed 5S ER was dialyzed against a buffer containing 0.5 M NaSCN, it was converted into a form sedimenting at 3.7 S +/- 0.1 (n = 3). It reverted to the 5 S molecular form when NaSCN was dialyzed away. Fluorographic analysis of both the 5 and 3.7 S ER following SDS-gel electrophoresis revealed one main band corresponding to Mr congruent to 66,000. After limited trypsin treatment of the 5 S ER, tamoxifen aziridine-binding protein sedimented at 4.3 S +/- 0.1 (n = 5), had a Stokes radius of 3.6 nm (calculated Mr = 65,000), and did not bind DNA. The same form was obtained after limited trypsin digestion of the ER bound to DNA-cellulose or to hsp 90 (the nontransformed 8-9 S ER molecular form). This 4.3 S trypsinized ER was reversibly dissociated by NaSCN into a congruent to 3 S +/- 0.1 (n = 3) molecular form. Fluorographic analysis of both the 4.3 and 3 S ER after SDS-gel electrophoresis showed one main radioactive band of Mr congruent to 30,000. Taken together our results suggest that 1) the 5 S ER is a homodimer of two Mr congruent to 66,000 hormone binding subunits which may be released as such from the nontransformed 8-9 S ER, 2) the trypsin digestion products yield two carboxyl-terminal fragments of Mr congruent to 30,000 that remain in the form of a dimer having lost their DNA-binding region, and 3) the trypsin cleavage would occur within the region located between the hormone-binding domain and the DNA-binding domain. These data indicate that the dimerization of the receptor occurs through hydrophobic interaction of its hormone-binding domain but cannot exclude that other part(s) of the receptor may also contribute to the dimer formation. The dimerization may be critically involved in the mechanism by which estradiol-receptor complexes promote change of gene transcription.

Chick heat-shock protein of Mr = 90,000, free or released from progesterone receptor, is in a dimeric form

A monoclonal antibody (BF4) has been used to characterize and purify the heat-shock protein of Mr approximately 90,000 (hsp 90) present in the chick oviduct. In low salt cytosol, the sedimentation coefficient of hsp 90 is approximately 6.8 S, the Stokes radius approximately 7.1 nm, and the calculated Mr approximately 204,000, thus suggesting a dimeric structure. In 0.4 M KCl cytosol, only slightly smaller values were determined (approximately 6.5 S, approximately 6.8 nm, and approximately 187,000). Following purification by ion exchange and immunoaffinity chromatography, hsp 90 migrated as a single silver-stained band at Mr approximately 90,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, while the sedimentation coefficient 6.2 S, the Stokes radius approximately 6.8 nm, and the Mr approximately 178,000 confirmed the dimeric structure. However, in both antigen or antibody excess conditions, only one molecule of monoclonal antibody could be bound to the hsp 90 dimer. Whether steric hindrance in a homodimer or the presence of two different 90-kDa proteins in a heterodimer explains this result cannot yet be decided. The dimer is not dissociated by high salt (1 M KCl) or the chaotropic agent (0.5 M NaSCN), but is disrupted by 4 M urea, suggesting a stabilization of the structure by hydrogen bonds. The molybdate-stabilized progesterone receptor hetero-oligomer form of approximately 8 S sedimentation coefficient was purified, and its hsp 90 component was then released by salt treatment. It was found to sediment at approximately 5.8 S and have a Stokes radius approximately 7.1 nm, giving Mr approximately 174,000. This observation is consistent with a previous report suggesting from specific activity determination, scanning of polyacrylamide gels, and cross-linking experiments that each purified nontransformed progesterone receptor molecule includes one progesterone binding unit per two 90-kDa protein molecules (Renoir, J. M., Buchou, T., Mester, J., Radanyi, C., and Baulieu, E. E. (1984) Biochemistry 23, 6016-6023). This work brings direct evidence that both free hsp 90 and the non-hormone binding hsp 90 component released from the nontransformed steroid receptor in the cytosol are in a dimeric form.