Dysfonctionnement systémique de la différenciation ostéoblastique des cellules souches adipeuses des patients atteints de myélome multiple

International audienceMultiple myeloma is characterized by bone lesions linked to increased osteoclast and decreased osteoblast activities. In particular, the osteoblast differentiation of bone marrow-derived stem cells (MSC) is impaired. Among the potential therapeutic tools for counteracting bone lesions, adipose-derived stem cells (ASC) could represent an appealing source for regenerative medicine due to their similar characteristics with MSC. Our study is among the first giving detailed insights into the osteoblastogenic capacities of ASC isolated by fat aspiration from myeloma patients (MM-ASC) compared to healthy subjects (HD-ASC). We showed that MM-ASC and HD-ASC exhibited comparable morphology, proliferative capacity, and immunophenotype. Unexpectedly, although normal in adipocyte differentiation, MM-ASC present a defective osteoblast differentiation, as indicated by less calcium deposition, decreased alkaline phosphatase activity, and downregulation of RUNX2 and osteocalcin. Furthermore, these ASC-derived osteoblasts displayed enhanced senescence, as shown by an increased β-galactosidase activity and cell cycle inhibitors expression (p16 INK4A , p21 WAF1/CIP1 .), associated with a markedly increased expression of DKK1, a major inhibitor of osteoblastogenesis in multiple myeloma. Interestingly, inhibition of DKK1 attenuated senescence and rescued osteoblast differentiation, highlighting its key role. Our findings show, for the first time, Cells 2019, 8, 441 2 of 16 that multiple myeloma is a systemic disease and suggest that ASC from patients would be unsuitable for tissue engineering designed to treat myeloma-associated bone disease.Le myélome multiple est caractérisé par des lésions osseuses liées à une augmentation de l'activité ostéoclastique et à une diminution de l'activité ostéoblastique. En particulier, la différenciation ostéoblastique des cellules souches issues de la moelle osseuse (CSM) est altérée. Parmi les outils thérapeutiques potentiels pour contrer les lésions osseuses, les cellules souches dérivées de l'adipeux (CSA) pourraient représenter une source intéressante pour la médecine régénérative en raison de leurs caractéristiques similaires à celles des cellules MSC. Notre étude est l'une des premières à donner un aperçu détaillé des capacités ostéoblastogènes de l'ASC isolée par aspiration graisseuse chez les patients atteints de myélome (MM-ASC) par rapport aux sujets sains (HD-ASC). Nous avons montré que le MM-ASC et le HD-ASC présentaient une morphologie, une capacité proliférative et un immunophénotype comparables. De façon inattendue, bien que normal dans la différenciation adipocytaire, le MM-ASC présente une différenciation ostéoblastique défectueuse, comme l'indiquent la diminution des dépôts de calcium, la diminution de l'activité des phosphatases alcalines et la régulation négative de RUNX2 et de l'ostéocalcine. De plus, ces ostéoblastes dérivés de l'ASC présentaient une sénescence accrue, comme en témoigne l'augmentation de l'activité de la β-galactosidase et de l'expression des inhibiteurs du cycle cellulaire (p16 INK4A, p21 WAF1/CIP1 .), associée à une expression nettement accrue du DKK1, un inhibiteur majeur de l'ostéoblastogenèse dans les myélomes multiples. Il est intéressant de noter que l'inhibition du DKK1 a atténué la sénescence et sauvé la différenciation des ostéoblastes, soulignant son rôle clé. Nos résultats montrent, pour la première fois, que le myélome multiple est une maladie systémique et suggèrent que les cellules 2019, 8, 441 2 sur 16 ne conviennent pas au génie tissulaire conçu pour traiter les maladies osseuses associées au myélome

Molecular and pathological signatures of epithelial–mesenchymal transitions at the cancer invasion front

Reduction of epithelial cell–cell adhesion via the transcriptional repression of cadherins in combination with the acquisition of mesenchymal properties are key determinants of epithelial–mesenchymal transition (EMT). EMT is associated with early stages of carcinogenesis, cancer invasion and recurrence. Furthermore, the tumor stroma dictates EMT through intensive bidirectional communication. The pathological analysis of EMT signatures is critically, especially to determine the presence of cancer cells at the resection margins of a tumor. When diffusion barriers disappear, EMT markers may be detected in sera from cancer patients. The detection of EMT signatures is not only important for diagnosis but can also be exploited to enhance classical chemotherapy treatments. In conclusion, further detailed understanding of the contextual cues and molecular mediators that control EMT will be required in order to develop diagnostic tools and small molecule inhibitors with potential clinical implications

Hybrid Molecularly Imprinted Polymers: The Future of Nanomedicine?

International audienceMolecularly imprinted polymers (MIPs) have been widely used in nanomedicine in the last few years. However, their potential is limited by their intrinsic properties resulting, for instance, in lack of control in drug release processes or complex detection for in vivo imaging. Recent attempts in creating hybrid nanomaterials combining MIPs with inorganic nanomaterials succeeded in providing a wide range of new interesting properties suitable for nanomedicine. Through this review, we aim to illustrate how hybrid molecularly imprinted polymers may improve patient care with enhanced imaging, treatments, and a combination of both

One‐Step Synthesis of Fluorescent Poly(divinylbenzene) Particles without Fluorescent Monomers

A simple and cost-efficient method for fluorescent microsphere synthesis, which does not require any fluorescent monomers or modification steps to incorporate fluorescent moieties into the polymer particles, is reported. Using rhodamine B and benzophenone as bimolecular initiation system in type II photoinitiated precipitation polymerization, the method enables the preparation of fluorescent microspheres in one step, at room temperature and without the need for a stabilizer or surfactant of any type

Osteopontin as a Regulator of Colorectal Cancer Progression and Its Clinical Applications

International audienceA high expression of the phosphoprotein osteopontin (OPN) has been associated with cancer progression in several tumor types, including breast cancer, hepatocarcinoma, ovarian cancer, and colorectal cancer (CRC). Interestingly, OPN is overexpressed in CRC and is associated with a poor prognosis linked to invasion and metastasis. Here, we review the regulation and functions of OPN with an emphasis on CRC. We examine how epigenetic and genetic regulators interact with the key signaling pathways involved in this disease. Then, we describe the role of OPN in cancer progression, including proliferation, survival, migration, invasion, and angiogenesis. Furthermore, we outline the interest of using OPN as a clinical biomarker, and discuss if and how osteopontin can be implemented as a routine assay in clinical laboratories for monitoring CRC patients. Finally, we discuss the use of OPN an attractive, but challenging, therapeutic target

A model for membrane degradation using a gelatin invadopodia assay

One of the most crucial and lethal characteristics of solid tumors is represented by the increased ability of cancer cells to migrate and invade other organs during the so-called metastatic spread. This is allowed thanks to the production of matrix metalloproteinases (MMPs), enzymes capable of degrading a type of collagen abundant in the basal membrane separating the epithelial tissue from the connective one. In this work, we employ a synergistic experimental and mathematical modelling approach to explore the invasion process of tumor cells. A mathematical model composed of reaction-diffusion equations describing the evolution of the tumor cells density on a gelatin substrate, MMPs enzymes concentration and the degradation of the gelatin is proposed. This is completed with a calibration strategy. We perform a sensitivity analysis and explore a parameter estimation technique both on synthetic and experimental data in order to find the optimal parameters that describe the in vitro experiments. A comparison between numerical and experimental solutions ends the work.Asymptotic approach to spatial and dynamical organization

p21(WAF1/CIP1) Selectively Controls the Transcriptional Activity of Estrogen Receptor α

Estrogen receptors (ER) are ligand-dependent transcription factors that regulate growth, differentiation, and maintenance of cellular functions in a wide variety of tissues. We report here that p21(WAF1/CIP1), a cyclin-dependent kinase (Cdk) inhibitor, cooperates with CBP to regulate the ERα-mediated transcription of endogenous target genes in a promoter-specific manner. The estrogen-induced expression of the progesterone receptor and WISP-2 mRNA transcripts in MCF-7 cells was enhanced by p21(WAF1/CIP1), whereas that of the cyclin D1 mRNA was reduced and the pS2 mRNA was not affected. Chromatin immunoprecipitation assays revealed that p21(WAF1/CIP1) was recruited simultaneously with ERα and CBP to the endogenous progesterone receptor gene promoter in an estrogen-dependent manner. Experiments in which the p21(WAF1/CIP1) protein was knocked down by RNA interference showed that the induction of the expression of the gene encoding the progesterone receptor required p21(WAF1/CIP1), in contrast with that of the cyclin D1 and pS2 genes. p21(WAF1/CIP1) induced not only cell cycle arrest in breast cancer cells but also milk fat globule protein and lipid droplets, indicators of the differentiated phenotype, as well as cell flattening and increase of the volume of the cytoplasm. These results indicate that p21(WAF1/CIP1), in addition to its Cdk-regulatory role, behaves as a transcriptional coactivator in a gene-specific manner implicated in cell differentiation