Akt-Activated Endothelium Increases Cancer Cell Proliferation and Resistance to Treatment in Ovarian Cancer Cell Organoids.

Ovarian cancer (OC) is a heterogeneous disease characterized by its late diagnosis (FIGO stages III and IV) and the importance of abdominal metastases often observed at diagnosis. Detached ovarian cancer cells (OCCs) float in ascites and form multicellular spheroids. Here, we developed endothelial cell (EC)-based 3D spheroids to better represent in vivo conditions. When co-cultured in 3D conditions, ECs and OCCs formed organized tumor angiospheres with a core of ECs surrounded by proliferating OCCs. We established that Akt and Notch3/Jagged1 pathways played a role in angiosphere formation and peritoneum invasion. In patients' ascites we found angiosphere-like structures and demonstrated in patients' specimens that tumoral EC displayed Akt activation, which supports the importance of Akt activation in ECs in OC. Additionally, we demonstrated the importance of FGF2, Pentraxin 3 (PTX3), PD-ECGF and TIMP-1 in angiosphere organization. Finally, we confirmed the role of Notch3/Jagged1 in OCC-EC crosstalk relating to OCC proliferation and during peritoneal invasion. Our results support the use of multicellular spheroids to better model tumoral and stromal interaction. Such models could help decipher the complex pathways playing critical roles in metastasis spread and predict tumor response to chemotherapy or anti-angiogenic treatment.

Akt-activated endothelium promotes ovarian cancer proliferation through notch activation.

BACKGROUND: One main challenge in ovarian cancer rests on the presence of a relapse and an important metastatic disease, despite extensive surgical debulking and chemotherapy. The difficulty in containing metastatic cancer is partly due to the heterotypic interaction of tumor and its microenvironment. In this context, evidence suggests that endothelial cells (EC) play an important role in ovarian tumor growth and chemoresistance. Here, we studied the role of tumor endothelium on ovarian cancer cells (OCCs). METHODS: We evaluated the effect of activated endothelial cells on ovarian cancer cell proliferation and resistance to chemotherapy and investigated the survival pathways activated by endothelial co-culture. RESULTS: The co-culture between OCCs and E4+ECs, induced an increase of OCCs proliferation both in vitro and in vivo. This co-culture induced an increase of Notch receptors expression on OCC surface and an increase of Jagged 1 expression on E4+ECs surface and activation of survival pathways leading to chemoresistance by E4+ECs. CONCLUSION: The targeting of aberrant NOTCH signaling could constitute a strategy to disrupt the pro-tumoral endothelial niche.

CCL2/CCL5 secreted by the stroma induce IL-6/PYK2 dependent chemoresistance in ovarian cancer.

BACKGROUND: Minimal residual disease is the main issue of advanced ovarian cancer treatment. According to the literature and previous results, we hypothesized that Mesenchymal Stromal Cells (MSC) could support this minimal residual disease by protecting ovarian cancer cells (OCC) from chemotherapy. In vitro study confirmed that MSC could induce OCC chemoresistance without contact using transwell setting. Further experiments showed that this induced chemoresistance was dependent on IL-6 OCC stimulation. METHODS: We combined meticulous in vitro profiling and tumor xenograft models to study the role of IL-6 in MSC/OCC intereactions. RESULTS: We demonstrated that Tocilizumab® (anti-IL-6R therapy) in association with chemotherapy significantly reduced the peritoneal carcinosis index (PCI) than chemotherapy alone in mice xenografted with OCCs+MSCs. Further experiments showed that CCL2 and CCL5 are released by MSC in transwell co-culture and induce OCCs IL-6 secretion and chemoresistance. Finally, we found that IL-6 induced chemoresistance was dependent on PYK2 phosphorylation. CONCLUSIONS: These findings highlight the potential key role of the stroma in protecting minimal residual disease from chemotherapy, thus favoring recurrences. Future clinical trials targeting stroma could use anti-IL-6 therapy in association with chemotherapy.

Surgical peritoneal stress creates a pro-metastatic niche promoting resistance to apoptosis via IL-8.

BACKGROUND: The mainstay of treatment of advanced ovarian cancer (AOC) involves chemotherapy, and debulking surgery. However, despite optimal surgical procedure and adjuvant chemotherapy, 60% of patients with AOC will relapse within 5 years. Most recurrences occur in the peritoneal cavity, suggesting the existence of occult sanctuaries where ovarian cancer cells (OCC) are protected. In murine models, surgical stress favors tumor growth; however, it has never been established that surgery may affect OCC sensitivity to subsequent chemotherapy. In this study, we investigated how the surgical stress could affect the chemosensitivity of OCC. METHODS: To avoid bias due to tumor burden in peritoneal cavity and duration of surgery, we used peritoneal biopsies from patients without a malignancy at precise time points. During laparotomies, peritoneal biopsies at the incision site were performed at the time of incision (H0 sample) and 1 h after initiation of surgery (H1 sample). We evaluated the chemoresistance to Taxol (0-20 µM) induced by H0 or H1 incubation (24 h) in two ovarian cancer cell lines OVCAR3 and SKOV3 and a primary cancer cell lines derived in our laboratory. RESULTS: Our results indicate that stressed peritoneum overexpressed cytokines, resulting in OCC increased resistance to therapy. Among these cytokines, IL8 was responsible for the resistance to apoptosis through the AKT pathway activation. Chemoresistance in OCC persists through the establishment of an autocrine IL8 loop. Finally, in a cohort of 32 patients, we showed an impact of IL8 tumoral overexpression on chemosensitivity and survival outcomes with a significant association to earlier recurrence. CONCLUSIONS: Our study demonstrated that precision surgery where targeted treatment would be used in combination with surgery is essential to obtain better tumor control.

Halfway between 2D and Animal Models: Are 3D Cultures the Ideal Tool to Study Cancer-Microenvironment Interactions?

An area that has come to be of tremendous interest in tumor research in the last decade is the role of the microenvironment in the biology of neoplastic diseases. The tumor microenvironment (TME) comprises various cells that are collectively important for normal tissue homeostasis as well as tumor progression or regression. Seminal studies have demonstrated the role of the dialogue between cancer cells (at many sites) and the cellular component of the microenvironment in tumor progression, metastasis, and resistance to treatment. Using an appropriate system of microenvironment and tumor culture is the first step towards a better understanding of the complex interaction between cancer cells and their surroundings. Three-dimensional (3D) models have been widely described recently. However, while it is claimed that they can bridge the gap between in vitro and in vivo, it is sometimes hard to decipher their advantage or limitation compared to classical two-dimensional (2D) cultures, especially given the broad number of techniques used. We present here a comprehensive review of the different 3D methods developed recently, and, secondly, we discuss the pros and cons of 3D culture compared to 2D when studying interactions between cancer cells and their microenvironment.

SDF-1alpha concentration dependent modulation of RhoA and Rac1 modifies breast cancer and stromal cells interaction.

BACKGROUND: The interaction of SDF-1alpha with its receptor CXCR4 plays a role in the occurrence of distant metastasis in many solid tumors. This interaction increases migration from primary sites as well as homing at distant sites. METHODS: Here we investigated how SDF-1α could modulate both migration and adhesion of cancer cells through the modulation of RhoGTPases. RESULTS: We show that different concentrations of SDF-1α modulate the balance of adhesion and migration in cancer cells. Increased migration was obtained at 50 and 100 ng/ml of SDF-1α; however migration was reduced at 200 ng/ml. The adhesion between breast cancer cells and BMHC was significantly increased by SDF-1α treatment at 200 ng/ml and reduced using a blocking monoclonal antibody against CXCR4. We showed that at low SDF-1α concentration, RhoA was activated and overexpressed, while at high concentration Rac1 was promoting SDF-1α mediating-cell adhesion. CONCLUSION: We conclude that SDF-1α concentration modulates migration and adhesion of breast cancer cells, by controlling expression and activation of RhoGTPases.

Epigenetics and Cardiovascular Disease in Diabetes.

Type 2 diabetes has become a major health issue worldwide. Chronic hyperglycemia induces a low-grade inflammation that, on top of other mechanisms, leads to endothelial dysfunction. Mounting evidence suggests that DNA methylation, post-translational modifications of histones, and long non-coding RNAs play an important role in the initiation, maintenance, and progression of both macro- and micro-vascular complications of diabetes. Long-term exposure to hyperglycemia induces epigenetic changes that could become irreversible, a phenomenon known as the 'metabolic memory.' Whether epigenetic-based therapies could be used to slow or limit the progression of cardiovascular disease remains unclear. While non-coding RNAs are currently investigated as potential biomarkers that predict diabetic cardiovascular disease incidence and progression, their therapeutic role is only hypothetical. In this review, we highlight the latest findings in experimental and clinical studies relevant to epigenetics and cardiovascular disease in diabetes.

Evidence for P-Glycoprotein Involvement in Cell Volume Regulation Using Coulter Sizing in Flow Cytometry.

The regulation of cell volume is an essential function that is coupled to a variety of physiological processes such as receptor recycling, excitability and contraction, cell proliferation, migration, and programmed cell death. Under stress, cells undergo emergency swelling and respond to such a phenomenon with a regulatory volume decrease (RVD) where they release cellular ions, and other osmolytes as well as a concomitant loss of water. The link between P-glycoprotein, a transmembrane transporter, and cell volume regulation is controversial, and changes in cells volume are measured using microscopy or electrophysiology. For instance, by using the patch-clamp method, our team demonstrated that chloride currents activated in the RVD were more intense and rapid in a breast cancer cell line overexpressing the P-glycoprotein (P-gp). The Cell Lab Quanta SC is a flow cytometry system that simultaneously measures electronic volume, side scatter and three fluorescent colors; altogether this provides unsurpassed population resolution and accurate cell counting. Therefore, here we propose a novel method to follow cellular volume. By using the Coulter-type channel of the cytometer Cell Lab Quanta SC MPL (multi-platform loading), we demonstrated a role for the P-gp during different osmotic treatments, but also a differential activity of the P-gp through the cell cycle. Altogether, our data strongly suggests a role of P-gp in cell volume regulation.

Differentially expressed circulating microRNAs in the development of acute diabetic Charcot foot.

AIM: Charcot foot (CF) is a rare complication of Type 2 diabetes (T2D). MATERIALS & METHODS: We assessed circulating miRNAs in 17 patients with T2D and acute CF (G1), 17 patients with T2D (G2) and equivalent neuropathy and 17 patients with T2D without neuropathy (G3) using the high-throughput miRNA expression profiling. RESULTS: 51 significantly deregulated miRNAs were identified in G1 versus G2, 37 in G1 versus G3 and 64 in G2 versus G3. Furthermore, we demonstrated that 16 miRNAs differentially expressed between G1 versus G2 could be involved in osteoclastic differentiation. Among them, eight are key factors involved in CF pathophysiology. CONCLUSION: Our data reveal that CF patients exhibit an altered expression profile of circulating miRNAs.

Coculturing with endothelial cells promotes in vitro maturation and electrical coupling of human embryonic stem cell-derived cardiomyocytes.

BACKGROUND: Pluripotent human embryonic stem cells (hESC) are a promising source of repopulating cardiomyocytes. We hypothesized that we could improve maturation of cardiomyocytes and facilitate electrical interconnections by creating a model that more closely resembles heart tissue; that is, containing both endothelial cells (ECs) and cardiomyocytes. METHODS: We induced cardiomyocyte differentiation in the coculture of an hESC line expressing the cardiac reporter NKX2.5-green fluorescent protein (GFP), and an Akt-activated EC line (E4+ECs). We quantified spontaneous beating rates, synchrony, and coordination between different cardiomyocyte clusters using confocal imaging of Fura Red-detected calcium transients and computer-assisted image analysis. RESULTS: After 8 days in culture, 94% ± 6% of the NKX2-5GFP+ cells were beating when hESCs embryonic bodies were plated on E4+ECs compared with 34% ± 12.9% for controls consisting of hESCs cultured on BD Matrigel (BD Biosciences) without ECs at Day 11 in culture. The spatial organization of beating areas in cocultures was different. The GFP+ cardiomyocytes were close to the E4+ECs. The average beats/min of the cardiomyocytes in coculture was faster and closer to physiologic heart rates compared with controls (50 ± 14 [n = 13] vs 25 ± 9 [n = 8]; p < 0.05). The coculture with ECs led to synchronized beating relying on the endothelial network, as illustrated by the loss of synchronization upon the disruption of endothelial bridges. CONCLUSIONS: The coculturing of differentiating cardiomyocytes with Akt-activated ECs but not EC-conditioned media results in (1) improved efficiency of the cardiomyocyte differentiation protocol and (2) increased maturity leading to better intercellular coupling with improved chronotropy and synchrony.

Circulating microparticles in acute diabetic Charcot foot exhibit a high content of inflammatory cytokines, and support monocyte-to-osteoclast cell induction.

Circulating microparticles (MPs) are major mediators in cardiovascular complications of type 2 diabetes (T2D); however, their contribution to Charcot foot (CF) disease is not known. Here, we purified and assessed the origin, concentration and content of circulating MPs from 33 individuals: 11 with T2D and acute CF, 11 T2D patients with equivalent neuropathy and 11 non-diabetic controls. First, we demonstrated that there were no differences in the distribution of MPs of endothelial, platelet origin among the 3 groups. However, MPs from leukocytes and monocytes origin were increased in CF patients. Moreover, we demonstrated that monocytes-derived MPs originated more frequently from intermediate and non-classical monocytes in CF patients. Five cytokines (G-CSF, GM-CSF, IL-1-ra, IL-2 and IL-16) were significantly increased in MPs from acute CF patients. Applying ingenuity pathways analysis, we found that those cytokines interacted well and induced the activation of pathways that are involved in osteoclast formation. Further, we treated THP-1 monocytes and monocytes sorted from healthy patients with CF-derived MPs during their differentiation into osteoclasts, which increased their differentiation into multinucleated osteoclast-like cells. Altogether, our study suggests that circulating MPs in CF disease have a high content of inflammatory cytokines and could increase osteoclast differentiation in vitro.

VE-cadherin cleavage by ovarian cancer microparticles induces ß-catenin phosphorylation in endothelial cells.

Microparticles (MPs) are increasingly recognized as important mediators of cell-cell communication in tumour growth and metastasis by facilitating angiogenesis-related processes. While the effects of the MPs on recipient cells are usually well described in the literature, the leading process remains unclear. Here we isolated MPs from ovarian cancer cells and investigated their effect on endothelial cells. First, we demonstrated that ovarian cancer MPs trigger ß-catenin activation in endothelial cells, inducing the upregulation of Wnt/ß-catenin target genes and an increase of angiogenic properties. We showed that this MPs mediated activation of ß-catenin in ECs was Wnt/Frizzled independent; but dependent on VE-cadherin localization disruption, αVß3 integrin activation and MMP activity. Finally, we revealed that Rac1 and AKT were responsible for ß-catenin phosphorylation and translocation to the nucleus. Overall, our results indicate that MPs released from cancer cells could play a major role in neo-angiogenesis through activation of beta catenin pathway in endothelial cells.

Applying chaperones to protein-misfolding disorders: molecular chaperones against α-synuclein in Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the accumulation of a protein called α-synuclein (α-syn) into inclusions known as lewy bodies (LB) within neurons. This accumulation is also due to insufficient formation and activity of dopamine produced in certain neurons within the substantia nigra. Lewy bodies are the pathological hallmark of the idiopathic disorder and the cascade that allows α-synuclein to misfold, aggregate and form these inclusions has been the subject of intensive research. Targeting these early steps of oligomerization is one of the main therapeutic approaches in order to develop neurodegenerative-modifying agents. Because the folding and refolding of alpha synuclein is the key point of this cascade, we are interested in this review to summarize the role of some molecular chaperones proteins such as Hsp70, Hsp90 and small heat shock proteins (sHsp) and Hsp 104. Hsp70 and its co-chaperone, Hsp70 and small heat shock proteins can prevent neurodegeneration by preventing α-syn misfolding, oligomerization and aggregation in vitro and in Parkinson disease animal models. Hsp104 is able to resolve disordered protein aggregates and cross beta amyloid conformers. Together, these chaperones have a complementary effect and can be a target for therapeutic intervention in PD.