Effect of persistent organic pollutants and pre-adipocytes in tumor progression in breast cancer

Malgré les avancées dans le diagnostic et le traitement du (CS), plus de 12 000 femmes décéderont de cette maladie en France cette année. Ces décès sont en grande partie dues à la dissémination de la maladie, la survie globale à 5 ans n'étant que de 26% dans les cas de formes métastatiques. Comprendre les facteurs de risque de progression tumorale et les mécanismes sous-jacents est un enjeu majeur en termes de santé publique notamment dans les populations à risque comme les patients obèses. Le tissu adipeux, composant majeur du microenvironnement tumoral dans le CS, est un réservoir important de polluants organiques persistants (POP) à la fois cancérigènes et perturbateurs endocriniens, et également une source interne chronique de ces molécules qui sont libérées de façon constante dans le sang. Outre leur effets toxiques et pro-invasifs directs, nous avons postulé l'hypothèse que ces POP, dont les dioxines, pouvaient avoir des interactions avec le tissu adipeux et modifier le phénotype des adipocytes péri-tumoraux dont l'effet pro-invasif sur les cellules tumorales est déjà connu. Les résultats de l'étude clinique METAPOP qui évalue l'association entre les taux sériques et adipeux de POP et la présence d'une atteinte métastatique ganglionnaire chez les patientes prise en charge pour un CS montrent que les concentrations de dioxines et de certains autres polluants donc plusieurs polychlorobiphényles dans le tissu adipeux sont positivement associées 1) au risque de métastase ganglionnaire et à la taille de la tumeur et 2) que cette association était encore plus forte chez les patientes présentant un IMC égal ou supérieur à 25 kg/m2 (c'est à dire une majorité de la population dans les pays Européens). Au niveau expérimental, à l'aide d'un système de co-culture en insert de cellules cancéreuses mammaires et de cellules pré-adipocytaires, exposées ou non à la dioxine, nous avons montré que la co-exposition « pré-adipocytes/polluant » entrainait des modifications majeures du phénotype des cellules cancéreuses mammaires avec l'acquisition d'un caractère « cellule souche cancéreuse » associé à la progression tumorale métastatique et à la chimiorésistance. Ce phénotype agressif et pro-métastatique est confirmé in vivo sur un modèle de xénogreffe chez l'embryon de poisson zèbre. La génération par la co-exposition de cellules géantes polynucléées est l'une des hypothèses pouvant expliquer l'acquisition de ces propriétés pro-invasives. Les POP pourraient ainsi contribuer à la progression tumorale et au développement métastatique dans le CS d'une part par leurs effets toxiques directs et d'autre part en ciblant le microenvironnement tumoral. Ces résultats pourraient expliquer le pronostic sombre chez les patientes obèses. Compte tenu du nombre important de cas, cette problématique représente potentiellement un problème majeur de santé publique, qui nécessite des investigations complémentaires pour mieux appréhender les mécanismes d'action mis en jeu.Despite advances in the diagnosis and treatment of breast cancer (BC), more than 12 000 women in France will die this year of this disease. Most of these deaths are due to the spread of cancer cells in the body, the 5-year overall survival is only 26% in metastatic forms. Understanding tumor progression risk factors and the underlying mechanisms is a major challenge in terms of public health, especially in high-risk populations such as obese patients. Adipose tissue, an important component in BC tumoral microenvironment, is a major reservoir of carcinogenic persistent organic pollutants (POP) and also a chronic internal source of pollutants that are released slowly in the blood. In addition to their direct toxic and pro-invasive effects, we postulated the hypothesis that these POP including dioxins, could interact with adipose tissue and change peritumoral adipocytes phenotype already known for their pro-invasive effects on cancer cells. The results of the METAPOP clinical trial, which assesses the association between serum and adipose levels of POPs and the presence of metastatic lymph node involvement in BC patients, show that concentrations of dioxins and some other pollutant as polychlorinated biphenyl in adipose tissue are positively associated 1/with the risk of lymph node metastasis and tumor size, and 2/ this association was even stronger in patients with BMI greater than or equal to 25 kg / m2 (more than 50% of the European population). At the experimental level, through an insert co-culture system of mammary cancer cells and pre-adipocyte cells, exposed or not to dioxin, we have shown that pre-adipocyte / pollutant co-exposure lead to major phenotypical modifications of breast cancer cells with the acquisition of "cancer stem cell" properties associated with metastatic tumor progression and chemoresistance. This aggressive and prometastatic phenotype is confirmed in vivo on a zebrafish embryo xenograft model. The generation by co-exposure of polynucleate giant cells is one of the hypotheses to explain the acquisition of these pro-invasive properties. POP could contribute to tumor progression and metastatic development in BC by their direct effects and by targeting the tumor microenvironment. These data could explain the poor prognosis in obese patients. Given to the high number of cases, this question is potentially a major public health concern and further investigations are needed to understand the mechanisms involved

Formation à l'éthique et à l'intégrité scientifique au sein des écoles doctorales françaises

La formation à l'éthique de la recherche et à l'intégrité scientifique des doctorants au cours de leur formation, toutes spécialités confondues, est obligatoire depuis 2016. Elle est confiée aux écoles doctorales, qui sont libres d'organiser cet enseignement comme elles le souhaitent. Nous avons réalisé une étude auprès de l'ensemble des écoles doctorales de France afin de connaître les modalités de cette formation en 2018. Il apparaît que ces écoles sont bien engagées dans cet enseignement sur l'ensemble du territoire et que la tendance est à son renforcement, ce qui témoigne d'une prise de conscience générale de l'importance de ces sujets pour la recherche de demain

The Role of the Kynurenine/AhR Pathway in Diseases Related to Metabolism and Cancer

The Aryl hydrocarbon receptor (AhR) is a xenobiotic and endobiotic receptor, which regulates many cellular processes from contaminant metabolism to immunomodulation. Consequently, it is also involved in pathophysiological pathways and now represents a potential therapeutical target. In this review, we will highlight the ancestral function of the protein together with an illustration of its ligand’s battery, emphasizing the different responses triggered by these high diverse molecules. Among them, several members of the kynurenine pathway (one key process of tryptophan catabolism) are AhR agonists and are subsequently involved in regulatory functions. We will finally display the interplay between Tryptophan (Trp) catabolism and dysregulation in metabolic pathways drawing hypothesis on the involvement of the AhR pathway in these cancer-related processes

Aggressiveness and Metastatic Potential of Breast Cancer Cells Co-Cultured with Preadipocytes and Exposed to an Environmental Pollutant Dioxin: An in Vitro and in Vivo Zebrafish Study

International audienceBACKGROUND: Breast cancer (BC) is a major public health concern, and its prognosis is very poor once metastasis occurs. The tumor microenvironment and chemical pollution have been suggested recently to contribute, independently, to the development of metastatic cells. The BC microenvironment consists, in part, of adipocytes and preadipocytes in which persistent organic pollutants (POPs) can be stored. OBJECTIVES: We aimed to test the hypothesis that these two factors (2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an extensively studied, toxic POP and the microenvironment) may interact to increase tumor aggressiveness. METHODS: We used a co-culture model using BC MCF-7 cells or MDA-MB-231 cells together with hMADS preadipocytes to investigate the contribution of the microenvironment and 2,3,7,8-tetrachlorodibenzo-p-dioxin TCDD on BC cells. Global differences were characterized using a highthroughput proteomic assay. Subsequently we measured the BC stem cell-like activity, analyzed the cell morphology, and used a zebrafish larvae model to study the metastatic potential of the BC cells. RESULTS: We found that coexposure to TCDD and preadipocytes modified BC cell properties; moreover, it induced the expression of ALDH1A3, a cancer stem cell marker, and the appearance of giant cancer cells with cell-in-cell structures (CICs), which are associated with malignant metastatic progression, that we demonstrated in vivo. DISCUSSION: The results of our study using BC cell lines co-cultured with preadipocytes and a POP and an in vivo zebrafish model of metastasis suggest that the interactions between BC cells and their microenvironment could affect their invasive or metastatic potential

Aryl Hydrocarbon Receptor and Its Diverse Ligands and Functions: An Exposome Receptor

International audienceThe aryl hydrocarbon receptor (AhR) is a transcriptional factor that regulates multiple functions following its activation by a variety of ligands, including xenobiotics, natural products, microbiome metabolites, and endogenous molecules. Because of this diversity, the AhR constitutes an exposome receptor. One of its main functions is to regulate several lines of defense against chemical insults and bacterial infections. Indeed, in addition to its well-established detoxication function, it has several functions at physiological barriers, and it plays a critical role in immunomodulation. The AhR is also involved in the development of several organs and their homeostatic maintenance. Its activity depends on the type of ligand and on the time frame of the receptor activation, which can be either sustained or transient, leading in some cases to opposite modes of regulations as illustrated in the regulation of different cancer pathways. The development of selective modulators and their pharmacological characterization are important areas of research

Outcomes of robotic surgery for endometrial cancer in elderly women

International audienceIntroduction: Few data have been reported on robot-assisted surgery in elderly. The objectives were to compare feasibility, complication data, and survival of patients under and upper the age of 70 who are managed for endometrial cancer by robot-assisted laparoscopy.Materials and methods: This is a retrospective comparative single-center study including patients treated between January 2007 and December 2016. Patients were divided into 2 groups: less than 70 years and greater than or equal to 70 years. The primary endpoint was the rate of complications. The secondary endpoints were conversion rate and follow-up.Results: 148 patients were included: 86 under 70 (group A) and 62 aged 70 and over (group B). More adhesiolysis was performed in group B (p < .01); the pelvic and para-aortic lymph node dissection rates were not different between both groups (p = .2 and p = .9). The operating times were significantly longer in group B (220.1 vs. 234.4 min, p = .02). The conversion rate was similar between the 2 groups (p = .7). The tumors were endometrioid adenocarcinomas for 77.9 and 66.7% respectively (p = .2), with grade 3 tumors more represented in older patients (24.4% vs. 48.4%, p < .01). There were more tumors at high risk of recurrence after 70 years (33.7 vs. 45.2%, p = .04). No significant difference was found for postoperative complications. There was no difference in overall survival (p = .7) or progression-free survival (p = .2). Undertreated women rate was similar in both groups (p = .1).Conclusion: Robotic surgery appears feasible and reproducible and could bring a benefit and allow optimal surgery without increasing the morbidity in the management of endometrial cancers whatever the age is

Associations between exposure to organochlorine chemicals and endometriosis in experimental studies: A systematic review protocol

Background: Endometriosis is a hormone-dependent gynaecological disease characterised by the presence and growth of endometrial tissues outside of the uterus. There is growing experimental evidence that suggests environmental endocrine disrupting chemicals, specifically organochlorine chemicals (OCCs), may play a role in the pathogenesis of endometriosis, but to date, there are no studies attempting to gather and synthesise the published literature systematically. Objectives: The main objective of this SR is to evaluate the associations between the exposure to OCCs and endometriosis in experimental models (in vivo and in vitro). Methods: The SR framework has been developed following the guidelines established in National Toxicology Program/Office of Health Assessment and Translation (NTP/OHAT) Handbook for Conducting a LiteratureBased Health Assessment, which provides a standardised methodology to implement the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to environmental health assessments. The review process will be managed and documented through HAWC, an open-source content management system, to guarantee transparency. Eligibility criteria: Only experimental studies, in vivo, ex vivo or in vitro, exploring associations between controlled exposures to OCCs and endometriosis and related outcomes will be included. Eligible studies will include peer reviewed articles of any publication date which are sources of primary data. Only studies published in English will be considered. Information sources: We will apply the search strings to the scientific literature databases NCBI PubMed, Web of Science and SCOPUS. Manual searches will be performed through the list of references of included articles. Data extraction and synthesis or results: Data will be extracted according to a pre-defined set of forms and synthesised in a narrative report. Given sufficient commensurate data, a meta-analysis may also be performed. Risk of bias: A quality assessment will be performed for in vivo and in vitro studies using the NTP/OHAT Risk of Bias Rating Tool for Human and Animal Studies. Level of evidence rating: Following a comprehensive assessment of the quality of evidence for both in vivo and in vitro studies, a confidence rating will be assigned to the body of literature and subsequently translated into a rating on the level of evidence (high, moderate, low, or inadequate) regarding the research question

Associations between Exposure to Organochlorine Chemicals and Endometriosis: A Systematic Review of Experimental Studies and Integration of Epidemiological Evidence

International audienceBACKGROUND: Growing epidemiological evidence suggests that organochlorine chemicals (OCCs), including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), may play a role in the pathogenesis of endometriosis.OBJECTIVES: We aimed to systematically review the experimental evidence (in vivo and in vitro) on the associations between exposure to OCCs and endometriosis-related end points.METHODS: A systematic review protocol was developed following the National Toxicology Program /Office of Health Assessment and Translation (NTP/OHAT) framework and managed within a web-based interface. In vivo studies designed to evaluate the impact of OCCs on the onset or progression of endometriosis and proliferation of induced endometriotic lesions were eligible. Eligible in vitro studies included single-cell and co-culture models to evaluate the proliferation, migration, and/or invasion of endometrial cells. We applied the search strings to PubMed, Web of Science, and Scopus ®. A final search was performed on 24 June 2020. Assessment of risk of bias and the level of evidence and integration of preevaluated epidemiological evidence was conducted using NTP/OHAT framework RESULTS: Out of 812 total studies, 39 met the predetermined eligibility criteria (15 in vivo, 23 in vitro, and 1 both). Most studies (n = 27) tested TCDD and other dioxin-like chemicals. In vivo evidence supported TCDD's promotion of endometriosis onset and lesion growth. In vitro evidence supported TCDD's promotion of cell migration and invasion, but there was insufficient evidence for cell proliferation. In vitro evidence further supported the roles of the aryl hydrocarbon receptor and matrix metalloproteinases in mediating steroidogenic disruption and inflammatory responses. Estrogen interactions were found across studies and end points.CONCLUSION: Based on the integration of a high level of animal evidence with a moderate level of epidemiological evidence, we concluded that TCDD was a known hazard for endometriosis in humans and the conclusion is supported by mechanistic in vitro evidence. Nonetheless, there is need for further research to fill in our gaps in understanding of the relationship between OCCs and their mixtures and endometriosis, beyond the prototypical TCDD

Adverse outcome pathway from activation of the AhR to breast cancer-related death

International audienceAdverse outcome pathways (AOPs) are formalized and structured linear concepts that connect one molecular initiating event (MIE) to an adverse outcome (AO) via different key events (KE) through key event relationships (KER). They are mainly used in ecotoxicology toxicology, and regulatory health issues. AOPs must respond to specific guidelines from the Organization for Economic Cooperation and Development (OECD) to weight the evidence between each KE. Breast cancer is the deadliest cancer in women with a poor prognosis in case of metastatic breast cancer. The role of the environments in the formation of metastasis has been suggested. We hypothesized that activation of the AhR (MIE), a xenobiotic receptor, could lead to breast cancer related death (AO), through different KEs, constituting a new AOP. An artificial intelligence tool (AOP-helpfinder), which screens the available literature, was used to collect all existing scientific abstracts to build a novel AOP, using a list of key words. Four hundred and seven abstracts were found containing at least a word from our MIE list and either one word from our AO or KE list. A manual curation retained 113 pertinent articles, which were also screened using PubTator. From these analyses, an AOP was created linking the activation of the AhR to breast cancer related death through decreased apoptosis, inflammation, endothelial cell migration, angiogenesis, and invasion. These KEs promote an increased tumor growth, angiogenesis and migration which leads to breast cancer metastasis and breast cancer related death. The evidence of the proposed AOP was weighted using the tailored Bradford Hill criteria and the OECD guidelines. The confidence in our AOP was considered strong. An in vitro validation must be carried out, but our review proposes a strong relationship between AhR activation and breast cancer-related death with an innovative use of an artificial intelligence literature search

Impact of mixtures of persistent organic pollutants on breast cancer aggressiveness

Introduction: Breast cancer (BC) is frequent with a poor prognosis in case of metastasis. The role of the environment has been poorly evaluated in its progression. We searched to assess whether a mixture of pollutants could be responsible of BC aggressiveness. Methods: Patients undergoing surgery for their BC were prospectively included in the METAPOP cohort. Forty-two POPs were extracted, among them 17 dioxins (PCDD/F), 16 polychlorobiphenyls (PCB), 8 polybromodiphenylethers (PBDE) and 2,2′,4,4′,5,5′-hexabromobiphenyl (PBB153) were measured in the adipose tissue surrounding the tumor. BC aggressiveness was defined using tumor size and metastasis (distant or lymph nodes). Two complementary models were used to evaluate the impact of the mixture of pollutants: the BKMR (Bayesian Kernel machine regression) and WQS (weighted quantile sum regression) models. The WQS estimates the weight (positive or negative) of a certain chemical based on its quantile and the BKMR model applies a kernel-based approach to estimate posterior inclusion probabilities. The sub-group of patients with a body mass index (BMI) > 22 kg/ m2 was also analyzed. Results: Ninety-one patients were included. Of these, 38 patients presented a metastasis, and the mean tumor size was 25.4 mm. The mean BMI was 24.5 kg/m2 (+/- 4.1). No statistical association was found in the general population. However, in patients with a BMI > 22 kg/ m2, our mixture was positively associated with tumor size (OR: 9.73 95 %CI: 1.30–18.15) and metastasis (OR = 3.98 95 %CI = 1.09–17.53) using the WQS model. Moreover, using the BKMR model on chemical families, dioxin like chemicals and PCDD were associated with a higher risk of metastasis. Discussion: These novel findings identified a mixture associated with breast cancer aggressiveness in patients with a BMI > 22 kg/ m2