Breast cancer stem cells with tumor- versus metastasis-initiating capacities are modulated by TGFBR1 inhibition

Cancer stem cells (CSCs) are defined by their ability to regenerate a tumor upon transplantation. However, it is not yet clear whether tumors contain a single CSC population or different subsets of cells with mixed capacities for initiating primary and secondary tumors. Using two different identification strategies, we studied the overlap between metastatic stem cells and tumor-initiating cells (TICs) in the MMTV-PyMT model. Our results show that in the MMTV-PyMT model, Lin−CD90−ALDHhigh cells retained a high tumor-initiating potential (TIP) in orthotopic transplants, in contrast to Lin−CD24+CD90+, which retained higher metastatic capacity. Interestingly, suppression of TGFβ signaling increased TIC numbers. We here describe the existence of distinct populations of CSCs with differing capacities to initiate tumors in the primary or the secondary site. Inhibiting TGFβ signaling shifts the balance toward the former, which may have unanticipated implications for the therapeutic use of TGFβ/TGFBR1 inhibitors

MAGI1 mediates eNOS activation and NO production in endothelial cells in response to fluid shear stress

Fluid shear stress stimulates endothelial nitric oxide synthase (eNOS) activation and nitric oxide (NO) production through multiple kinases, including protein kinase A (PKA), AMP-activated protein kinase (AMPK), AKT and Ca2+/calmodulin-dependent protein kinase II (CaMKII). Membrane-associated guanylate kinase (MAGUK) with inverted domain structure-1 (MAGI1) is an adaptor protein that stabilizes epithelial and endothelial cell-cell contacts. The aim of this study was to assess the unknown role of endothelial cell MAGI1 in response to fluid shear stress. We show constitutive expression and co-localization of MAGI1 with vascular endothelial cadherin (VE- cadherin) in endothelial cells at cellular junctions under static and laminar flow conditions. Fluid shear stress increases MAGI1 expression. MAGI1 silencing perturbed flow-dependent responses, specifically, Krüppel-like factor 4 (KLF4) expression, endothelial cell alignment, eNOS phosphorylation and NO production. MAGI1 overexpression had opposite effects and induced phosphorylation of PKA, AMPK, and CAMKII. Pharmacological inhibition of PKA and AMPK prevented MAGI1- mediated eNOS phosphorylation. Consistently, MAGI1 silencing and PKA inhibition suppressed the flow-induced NO production. Endothelial cell-specific transgenic expression of MAGI1 induced PKA and eNOS phosphorylation in vivo and increased NO production ex vivo in isolated endothelial cells. In conclusion, we have identified endothelial cell MAGI1 as a previously unrecognized mediator of fluid shear stress- induced and PKA/AMPK dependent eNOS activation and NO productio

Obesity promotes the expansion of metastasis-initiating cells in breast cancer

Obesity is a strong predictor of poor prognosis in breast cancer, especially in postmenopausal women. In particular, tumors in obese patients tend to seed more distant metastases, although the biology behind this observation remains poorly understood.Methods: To elucidate the effects of the obese microenvironment on metastatic spread, we ovariectomized C57BL/6 J female mice and fed them either a regular diet (RD) or a high-fat diet (HFD) to generate a postmenopausal diet-induced obesity model. We then studied tumor progression to metastasis of Py230 and EO771 grafts. We analyzed and phenotyped the RD and HFD tumors and the surrounding adipose tissue by flow cytometry, qPCR, immunohistochemistry (IHC) and western blot. The influence of the microenvironment on tumor cells was assessed by performing cross-transplantation of RD and HFD tumor cells into other RD and HFD mice. The results were analyzed using the unpaired Student t test when comparing two variables, otherwise we used one-way or two-way analysis of variance. The relationship between two variables was calculated using correlation coefficients.Results: Our results show that tumors in obese mice grow faster, are also less vascularized, more hypoxic, of higher grade and enriched in CD11b+Ly6G+ neutrophils. Collectively, this favors induction of the epithelial-to-mesenchymal transition and progression to claudin-low breast cancer, a subtype of triple-negative breast cancer that is enriched in cancer stem cells. Interestingly, transplanting HFD- derived tumor cells in RD mice transfers enhanced tumor growth and lung metastasis formation.Conclusions: These data indicate that a pro-metastatic effect of obesity is acquired by the tumor cells in the primary tumor independently of the microenvironment of the secondary site

Étude des effets de l'adénosine sur le remodelage ventriculaire gauche survenant après un infarctus du myocarde

Left ventricular (LV) remodeling can follow myocardial infarction (MI), an acute ischemic event which occurs after occlusion of a coronary artery. Remodeling allows maintaining and adapting cardiac function by geometric and functional changes of the myocardium. If this process becomes maladaptive, the patients? prognostic and life quality are impaired by the development of heart failure. Adenosine is an ubiquitous nucleoside with partially characterized effects on LV remodeling. These effects depend on the type of receptor activated. Previous in vitro studies from our laboratory have shown that adenosine regulates several key processes involved in LV remodeling. Here, we hypothesized that adenosine may have beneficial effects on LV remodeling after MI. First, we showed that positon emission tomography (PET) can accurately characterize MI severity and predicts subsequent LV remodeling in the rat model of MI induced by coronary occlusion. Using this technique, we described the case of a rat that survived after a massive infarct covering 70% of the left ventricle. Second, we showed that a chronic administration of adenosine preserves cardiac contractility in the border zone, two months after MI. This cardioprotective effect can be explained, in part, by the stimulation of angiogenesis involving a stimulation of the recruitment of endothelial progenitor cells to the heart. Then, we showed that the Monocyte Chemotactic Protein 3 stimulates the migration of endothelial progenitor cells and is thereby a potential therapeutic target after MI. Finally, we started the preclinical study of an A2A agonist / A3 antagonist, a promising candidate to prevent LV remodeling after MILe remodelage ventriculaire est un processus réactionnel pouvant faire suite à un infarctus du myocarde (IDM), évènement ischémique aigu survenant lors de l'obstruction d'une artère coronaire. Le remodelage provoque alors des changements géométriques et fonctionnels du tissu myocardique qui permettent de maintenir et d'adapter la fonction cardiaque. Lorsque ce processus est délétère, la maladie évolue vers l'insuffisance cardiaque, ce qui altère le pronostic et la qualité de vie des patients. L'adénosine est un nucléoside ubiquitaire dont les effets sur le remodelage ventriculaire après IDM sont encore peu connus et dépendent du type de récepteur activé. Au sein de notre laboratoire, de précédentes études in vitro ont montré que l'adénosine régule de nombreux acteurs clés du remodelage. Dans ce travail de thèse, nous avons émis l'hypothèse que l'adénosine pouvait avoir un effet bénéfique sur le remodelage ventriculaire après la survenue d'un IDM. Dans un premier temps, nous avons montré que la tomographie par émission de positrons (TEP) permet de caractériser précisément les séquelles d'IDM et de prédire le remodelage ventriculaire chez le rat après occlusion coronaire. Cette technique nous a permis de mettre en évidence le cas d'un rat ayant survécu à un IDM touchant plus de 70% de son ventricule gauche. Dans un deuxième temps, nous avons montré que l'administration chronique d'adénosine, à long terme après IDM chez le rat, permet de maintenir la contractilité cardiaque dans la zone bordant l'IDM. Cet effet cardioprotecteur peut s'expliquer par une stimulation de l'angiogenèse elle-même due à un recrutement de cellules endothéliales progénitrices circulantes. Ensuite, nous avons montré que la chimiokine Monocyte Chemotactic Protein 3 est capable de stimuler la migration des cellules endothéliales progénitrices et est ainsi un agent thérapeutique potentiel après IDM. Enfin, nous avons commencé l'étude préclinique d'une molécule agoniste du récepteur A2A à l'adénosine et antagoniste du récepteur A3, un candidat particulièrement prometteur pour prévenir le remodelage ventriculaire après ID

Study of the effects of adenosine on left ventricular remodelling

Le remodelage ventriculaire est un processus réactionnel pouvant faire suite à un infarctus du myocarde (IDM), évènement ischémique aigu survenant lors de l'obstruction d'une artère coronaire. Le remodelage provoque alors des changements géométriques et fonctionnels du tissu myocardique qui permettent de maintenir et d'adapter la fonction cardiaque. Lorsque ce processus est délétère, la maladie évolue vers l'insuffisance cardiaque, ce qui altère le pronostic et la qualité de vie des patients. L'adénosine est un nucléoside ubiquitaire dont les effets sur le remodelage ventriculaire après IDM sont encore peu connus et dépendent du type de récepteur activé. Au sein de notre laboratoire, de précédentes études in vitro ont montré que l'adénosine régule de nombreux acteurs clés du remodelage. Dans ce travail de thèse, nous avons émis l'hypothèse que l'adénosine pouvait avoir un effet bénéfique sur le remodelage ventriculaire après la survenue d'un IDM. Dans un premier temps, nous avons montré que la tomographie par émission de positrons (TEP) permet de caractériser précisément les séquelles d'IDM et de prédire le remodelage ventriculaire chez le rat après occlusion coronaire. Cette technique nous a permis de mettre en évidence le cas d'un rat ayant survécu à un IDM touchant plus de 70% de son ventricule gauche. Dans un deuxième temps, nous avons montré que l'administration chronique d'adénosine, à long terme après IDM chez le rat, permet de maintenir la contractilité cardiaque dans la zone bordant l'IDM. Cet effet cardioprotecteur peut s'expliquer par une stimulation de l'angiogenèse elle-même due à un recrutement de cellules endothéliales progénitrices circulantes. Ensuite, nous avons montré que la chimiokine Monocyte Chemotactic Protein 3 est capable de stimuler la migration des cellules endothéliales progénitrices et est ainsi un agent thérapeutique potentiel après IDM. Enfin, nous avons commencé l'étude préclinique d'une molécule agoniste du récepteur A2A à l'adénosine et antagoniste du récepteur A3, un candidat particulièrement prometteur pour prévenir le remodelage ventriculaire après IDMLeft ventricular (LV) remodeling can follow myocardial infarction (MI), an acute ischemic event which occurs after occlusion of a coronary artery. Remodeling allows maintaining and adapting cardiac function by geometric and functional changes of the myocardium. If this process becomes maladaptive, the patients? prognostic and life quality are impaired by the development of heart failure. Adenosine is an ubiquitous nucleoside with partially characterized effects on LV remodeling. These effects depend on the type of receptor activated. Previous in vitro studies from our laboratory have shown that adenosine regulates several key processes involved in LV remodeling. Here, we hypothesized that adenosine may have beneficial effects on LV remodeling after MI. First, we showed that positon emission tomography (PET) can accurately characterize MI severity and predicts subsequent LV remodeling in the rat model of MI induced by coronary occlusion. Using this technique, we described the case of a rat that survived after a massive infarct covering 70% of the left ventricle. Second, we showed that a chronic administration of adenosine preserves cardiac contractility in the border zone, two months after MI. This cardioprotective effect can be explained, in part, by the stimulation of angiogenesis involving a stimulation of the recruitment of endothelial progenitor cells to the heart. Then, we showed that the Monocyte Chemotactic Protein 3 stimulates the migration of endothelial progenitor cells and is thereby a potential therapeutic target after MI. Finally, we started the preclinical study of an A2A agonist / A3 antagonist, a promising candidate to prevent LV remodeling after M

Étude des effets de l'adénosine sur le remodelage ventriculaire gauche survenant après un infarctus du myocarde

Le remodelage ventriculaire est un processus réactionnel pouvant faire suite à un infarctus du myocarde (IDM), évènement ischémique aigu survenant lors de l'obstruction d'une artère coronaire. Le remodelage provoque alors des changements géométriques et fonctionnels du tissu myocardique qui permettent de maintenir et d'adapter la fonction cardiaque. Lorsque ce processus est délétère, la maladie évolue vers l'insuffisance cardiaque, ce qui altère le pronostic et la qualité de vie des patients. L'adénosine est un nucléoside ubiquitaire dont les effets sur le remodelage ventriculaire après IDM sont encore peu connus et dépendent du type de récepteur activé. Au sein de notre laboratoire, de précédentes études in vitro ont montré que l'adénosine régule de nombreux acteurs clés du remodelage. Dans ce travail de thèse, nous avons émis l'hypothèse que l'adénosine pouvait avoir un effet bénéfique sur le remodelage ventriculaire après la survenue d'un IDM. Dans un premier temps, nous avons montré que la tomographie par émission de positrons (TEP) permet de caractériser précisément les séquelles d'IDM et de prédire le remodelage ventriculaire chez le rat après occlusion coronaire. Cette technique nous a permis de mettre en évidence le cas d'un rat ayant survécu à un IDM touchant plus de 70% de son ventricule gauche. Dans un deuxième temps, nous avons montré que l'administration chronique d'adénosine, à long terme après IDM chez le rat, permet de maintenir la contractilité cardiaque dans la zone bordant l'IDM. Cet effet cardioprotecteur peut s'expliquer par une stimulation de l'angiogenèse elle-même due à un recrutement de cellules endothéliales progénitrices circulantes. Ensuite, nous avons montré que la chimiokine Monocyte Chemotactic Protein 3 est capable de stimuler la migration des cellules endothéliales progénitrices et est ainsi un agent thérapeutique potentiel après IDM. Enfin, nous avons commencé l'étude préclinique d'une molécule agoniste du récepteur A2A à l'adénosine et antagoniste du récepteur A3, un candidat particulièrement prometteur pour prévenir le remodelage ventriculaire après IDMLeft ventricular (LV) remodeling can follow myocardial infarction (MI), an acute ischemic event which occurs after occlusion of a coronary artery. Remodeling allows maintaining and adapting cardiac function by geometric and functional changes of the myocardium. If this process becomes maladaptive, the patients? prognostic and life quality are impaired by the development of heart failure. Adenosine is an ubiquitous nucleoside with partially characterized effects on LV remodeling. These effects depend on the type of receptor activated. Previous in vitro studies from our laboratory have shown that adenosine regulates several key processes involved in LV remodeling. Here, we hypothesized that adenosine may have beneficial effects on LV remodeling after MI. First, we showed that positon emission tomography (PET) can accurately characterize MI severity and predicts subsequent LV remodeling in the rat model of MI induced by coronary occlusion. Using this technique, we described the case of a rat that survived after a massive infarct covering 70% of the left ventricle. Second, we showed that a chronic administration of adenosine preserves cardiac contractility in the border zone, two months after MI. This cardioprotective effect can be explained, in part, by the stimulation of angiogenesis involving a stimulation of the recruitment of endothelial progenitor cells to the heart. Then, we showed that the Monocyte Chemotactic Protein 3 stimulates the migration of endothelial progenitor cells and is thereby a potential therapeutic target after MI. Finally, we started the preclinical study of an A2A agonist / A3 antagonist, a promising candidate to prevent LV remodeling after MIMETZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Obesity promotes the expansion of metastasis-initiating cells in breast cancer

Abstract Background Obesity is a strong predictor of poor prognosis in breast cancer, especially in postmenopausal women. In particular, tumors in obese patients tend to seed more distant metastases, although the biology behind this observation remains poorly understood. Methods To elucidate the effects of the obese microenvironment on metastatic spread, we ovariectomized C57BL/6 J female mice and fed them either a regular diet (RD) or a high-fat diet (HFD) to generate a postmenopausal diet-induced obesity model. We then studied tumor progression to metastasis of Py230 and EO771 grafts. We analyzed and phenotyped the RD and HFD tumors and the surrounding adipose tissue by flow cytometry, qPCR, immunohistochemistry (IHC) and western blot. The influence of the microenvironment on tumor cells was assessed by performing cross-transplantation of RD and HFD tumor cells into other RD and HFD mice. The results were analyzed using the unpaired Student t test when comparing two variables, otherwise we used one-way or two-way analysis of variance. The relationship between two variables was calculated using correlation coefficients. Results Our results show that tumors in obese mice grow faster, are also less vascularized, more hypoxic, of higher grade and enriched in CD11b+Ly6G+ neutrophils. Collectively, this favors induction of the epithelial-to-mesenchymal transition and progression to claudin-low breast cancer, a subtype of triple-negative breast cancer that is enriched in cancer stem cells. Interestingly, transplanting HFD-derived tumor cells in RD mice transfers enhanced tumor growth and lung metastasis formation. Conclusions These data indicate that a pro-metastatic effect of obesity is acquired by the tumor cells in the primary tumor independently of the microenvironment of the secondary site. Graphical abstract Effects of postmenopausal obesity on primary breast cancer tumours

Cardioprotective effects of adenosine within the border and remote areas of myocardial infarction.

International audienceBACKGROUND: Adenosine may have beneficial effects on left ventricular function after myocardial infarction (MI), but the magnitude of this effect on remote and MI areas is controversial. We assessed the long-term effects of adenosine after MI using electrocardiogram-triggered 18 F-fluorodeoxyglucose positron emission tomography. METHODS: Wistar rats were subjected to coronary ligation and randomized into three groups treated daily for 2 months by NaCl (control; n = 7), 2-chloroadenosine (CADO; n = 8) or CADO with 8-sulfophenyltheophilline, an antagonist of adenosine receptors (8-SPT; n = 8). RESULTS: After 2 months, control rats exhibited left ventricular remodelling, with increased end-diastolic volume and decreased ejection fraction. Left ventricular remodelling was not significantly inhibited by CADO. Segmental contractility, as assessed by the change in myocardial thickening after 2 months, was improved in CADO rats compared to control rats (+1.6% +/- 0.8% vs. -2.3% +/- 0.8%, p < 0.001). This improvement was significant in border (+5.6% +/- 0.8% vs. +1.5% +/- 0.8%, p < 0.001) and remote (-4.0% +/- 1.0% vs. -10.4% +/- 1.3%, p < 0.001) segments, but absent in MI segments. Histological analyses revealed that CADO reduced fibrosis, cardiomyocyte hypertrophy and apoptosis. Protective effects of CADO were blunted by 8-SPT. CONCLUSION: Long-term administration of adenosine protects the left ventricle from contractile dysfunction following MI

Adenosine Stimulates the Migration of Human Endothelial Progenitor Cells. Role ofCXCR4 and MicroRNA-150

International audienceBACKGROUND:Administration of endothelial progenitor cells (EPC) represents a promising option to regenerate the heart after myocardial infarction, but is limited because of low recruitment and engraftment in the myocardium. Mobilization and migration of EPC are mainly controlled by stromal cell-derived factor 1α (SDF-1α) and its receptor CXCR4. We hypothesized that adenosine, a cardioprotective molecule, may improve the recruitment of EPC to the heart.METHODS:EPC were obtained from peripheral blood mononuclear cells of healthy volunteers. Expression of chemokines and their receptors was evaluated using microarrays, quantitative PCR, and flow cytometry. A Boyden chamber assay was used to assess chemotaxis. Recruitment of EPC to the infarcted heart was evaluated in rats after permanent occlusion of the left anterior descending coronary artery.RESULTS:Microarray analysis revealed that adenosine modulates the expression of several members of the chemokine family in EPC. Among these, CXCR4 was up-regulated by adenosine, and this result was confirmed by quantitative PCR (3-fold increase, P<0.001). CXCR4 expression at the cell surface was also increased. This effect involved the A(2B) receptor. Pretreatment of EPC with adenosine amplified their migration towards recombinant SDF-1α or conditioned medium from cardiac fibroblasts. Both effects were abolished by CXCR4 blocking antibodies. Adenosine also increased CXCR4 under ischemic conditions, and decreased miR-150 expression. Binding of miR-150 to the 3' untranslated region of CXCR4 was verified by luciferase assay. Addition of pre-miR-150 blunted the effect of adenosine on CXCR4. Administration of adenosine to rats after induction of myocardial infarction stimulated EPC recruitment to the heart and enhanced angiogenesis.CONCLUSION:Adenosine increases the migration of EPC. The mechanism involves A(2B) receptor activation, decreased expression of miR-150 and increased expression of CXCR4. These results suggest that adenosine may be used to enhance the capacity of EPC to revascularize the ischemic heart