Mary Poupot

A Phosphorus-Based Dendrimer Targets Inflammation and Osteoclastogenesis in Experimental Arthritis

A phosphorus-based dendrimer suppresses inflammation and reduces bone erosion in mouse models of rheumatoid arthritis. Dendrimer Doubles Up Rheumatoid arthritis (RA) is an autoimmune inflammatory disease that is characterized by inflamed synovial tissue, cartilage degeneration, and bone erosion, leading to joint deformation and physical handicap. Biologic therapeutic approaches, such as monoclonal antibodies and soluble receptors, have been developed to relieve the symptoms of RA. Unfortunately, these drugs typically act on a single target: proinflammatory cytokines. There is an unmet clinical need for anti-RA drugs that target not only proinflammatory molecules and pathways, but also the osteoclastic differentiation of monocytes—a process that leads to bone resorption. In response, Hayder et al. synthesized a new dendrimer-based therapeutic that boasts a two-pronged attack on RA, with both anti-inflammatory and anti-osteoclastogenic activity. Dendrimers are highly branched polymers whose multivalency allows for interaction with several cellular and molecular targets. The authors created an azabisphosphonate (ABP)–capped dendrimer that has been shown to target human monocytes and direct them toward an anti-inflammatory response. Two animal models of autoimmune arthritis were used: the IL-1ra−/− mouse and the K/BxN serum transfer mouse. Dendrimer ABP was administered to IL-1ra−/− mice via weekly intravenous injections. At high doses, the dendrimer completely inhibited inflammation, as evidenced by a decrease in paw swelling, and prevented arthritis histopathology, with ankle joints showing near-normal synovial membranes and intact cartilage after 12 weeks. Dendrimer ABP also decreased the amount of proinflammatory cytokines and increased levels of anti-inflammatory cytokines interleukin-4 (IL-4) and IL-10, thereby suggesting a skewing toward a T helper 2 (TH2) response. The K/BxN mouse demonstrated similar results upon treatment with dendrimer ABP. Treatment with dendrimer ABP also prevented osteoclastogenesis, as shown in human synovial tissue ex vivo and human peripheral blood monocytes in vitro. The authors further outlined a potential dendrimer-mediated mechanism that involves inhibition of c-FMS—a signaling molecule that promotes monocyte differentiation into osteoclasts. This study by Hayder and colleagues has shown that dendrimer ABP, by doubling up against inflammation and bone erosion, might be more effective at treating RA than existing antibody- and small-molecule–based biologic drugs. Dendrimers are highly branched “tree-like” polymers that have demonstrated therapeutic potential in drug delivery, medical imaging, and tissue engineering in recent years. In addition, we have shown that an azabisphosphonate (ABP)–capped dendrimer selectively targets monocytes and directs them toward anti-inflammatory activation. We explored this property to assess the therapeutic potential of dendrimer ABP in the treatment of an inflammatory disease, rheumatoid arthritis. Intravenous injections of dendrimer ABP inhibited the development of inflammatory arthritis in two animal models: IL-1ra−/− mice and mice undergoing K/BxN serum transfer. Suppression of disease was characterized by normal synovial membranes, reduced levels of inflammatory cytokines, and the absence of cartilage destruction and bone erosion. Dendrimer ABP also exhibited anti-osteoclastic activity on mouse and human cells, mediated by c-FMS (cellular-feline McDonough strain sarcoma virus oncogene homolog) inhibition. These preclinical demonstrations suggest the potential use of dendrimer ABP as a nanotherapeutic for rheumatoid arthritis.

What lessons can be learned from γδ T cell-based cancer immunotherapy trials?

During the last several years, research has produced a significant amount of knowledge concerning the characteristics of human γδ T lymphocytes. Findings regarding the immune functions of these cells, particularly their natural killer cell-like lytic activity against tumor cells, have raised expectations for the therapeutic applications of these cells for cancer. Pharmaceutical companies have produced selective agonists for these lymphocytes, and several teams have launched clinical trials of γδ T cell-based cancer therapies. The findings from these studies include hematological malignancies (follicular lymphoma, multiple myeloma, acute and chronic myeloid leukemia), as well as solid tumors (renal cell, breast and prostate carcinomas), consisting of samples from more than 250 patients from Europe, Japan and the United States. The results of these pioneering studies are now available, and this short review summarizes the lessons learned and the role of γδ T cell-based strategies in the current landscape of cancer immunotherapies.

Tailored Control and Optimisation of the Number of Phosphonic Acid Termini on Phosphorus‐Containing Dendrimers for the Ex‐Vivo Activation of Human Monocytes

The syntheses of a series of phosphonic acid-capped dendrimers is described. This collection is based on a unique set of dendritic structural parameters-cyclo(triphosphazene) core, benzylhydrazone branches and phosphonic acid surface-and was designed to study the influence of phosphonate (phosphonic acid) surface loading towards the activation of human monocytes ex vivo. Starting from the versatile hexachloro-cyclo(triphosphazene) N(3)P(3)Cl(6), six first-generation dendrimers were obtained, bearing one to six full branches, that lead to 4, 8, 12, 16, 20 and 24 phosphonate termini, respectively. The surface loading was also explored at the limit of dense packing by means of a first-generation dendrimer having a cyclo(tetraphosphazene) core and bearing 32 termini, and with a first-generation dendrimer based on a AB(2)/CD(5) growing pattern and bearing 60 termini. Human monocyte activation by these dendrimers confirms the requirement of the whole dendritic structure for bioactivity and identifies the dendrimer bearing four branches, thus 16 phosphonate termini, as the most bioactive.

Oncologic Trogocytosis of an Original Stromal Cells Induces Chemoresistance of Ovarian Tumours

Background The microenvironment plays a major role in the onset and progression of metastasis. Epithelial ovarian cancer (EOC) tends to metastasize to the peritoneal cavity where interactions within the microenvironment might lead to chemoresistance. Mesothelial cells are important actors of the peritoneal homeostasis; we determined their role in the acquisition of chemoresistance of ovarian tumours. Methodology/Principal Findings We isolated an original type of stromal cells, referred to as “Hospicells” from ascitis of patients with ovarian carcinosis using limiting dilution. We studied their ability to confer chemoresistance through heterocellular interactions. These stromal cells displayed a new phenotype with positive immunostaining for CD9, CD10, CD29, CD146, CD166 and Multi drug resistance protein. They preferentially interacted with epithelial ovarian cancer cells. This interaction induced chemoresistance to platin and taxans with the implication of multi-drug resistance proteins. This contact enabled EOC cells to capture patches of the Hospicells membrane through oncologic trogocytosis, therefore acquiring their functional P-gp proteins and thus developing chemoresistance. Presence of Hospicells on ovarian cancer tissue micro-array from patients with neo-adjuvant chemotherapy was also significantly associated to chemoresistance. Conclusions/Significance This is the first report of trogocytosis occurring between a cancer cell and an original type of stromal cell. This interaction induced autonomous acquisition of chemoresistance. The presence of stromal cells within patients tumour might be predictive of chemoresistance. The specific interaction between cancer cells and stromal cells might be targeted during chemotherapy.

Recent Advances in Microwave-Based Dielectric Spectroscopy at the Cellular Level for Cancer Investigations

Cancer remains a leading cause of death in the world. To overcome this problem, it is necessary to develop new analysis tools, in complementarity to existing ones, to enable the early diagnostic of the diseases, personalized treatment, and further fundamental cancer mechanisms understanding. In this context, microwave-based and millimeter-wave-based dielectric spectroscopy performed at the cellular and molecular levels is progressively emerging, as it permits the non-invasive and real-time probing of cells in their culture biological medium. The recent advances of this topic are given in this paper with a specific highlight of its various assets.

Spontaneous Membrane Transfer Through Homotypic Synapses Between Lymphoma Cells

Formation of an immunological synapse by T, B, or NK cells is associated with an intercellular transfer of some membrane fragments from their respective target cells. This capture is thought to require effector cell activation by surface recognition of stimulatory ligand(s). However, spontaneous synaptic transfers between homotypic lymphoid cells has never been described. In this study, we show that without adding Ag, resting healthy lymphoid cells and several tumor cell lines are inactive. Conversely, however, some leukemia cell lines including the Burkitt’s lymphoma Daudi continuously uptake patches of autologous cell membranes. This intercellular transfer does not involve cytosol molecules or exosomes, but requires cell contact. In homotypic Daudi cell conjugates, this occurs through immunological synapses, involves constitutive protein kinase C and mitogen-activated protein/extracellular signal-regulated kinase kinase activity and strongly increases upon B cell receptor activation. Thus, spontaneous homosynaptic transfer may reflect the hitherto unsuspected autoreactivity of some leukemia cell lines.

Accurate Nanoliter Liquid Characterization Up to 40 GHz for Biomedical Applications: Toward Noninvasive Living Cells Monitoring

This paper demonstrates an accurate liquid sensing technique, from 40 MHz to 40 GHz, which is suitable for the detection and quantification of very small contents of molecules, proteins, and for the noninvasive and contactless microwave investigation of living cells in their culture medium. The sensor is based on an interdigitated capacitor (IDC) with a microfluidic channel to confine the nanoliter-range liquid and is integrated with microtechnologies to be fully compatible with a massive parallelization at low cost. Both alcohol and biological aqueous solutions are precisely characterized, identified, and quantified in terms of capacitance and conductances contrasts with respect to pure de-ionized water. Mixtures from 20% down to 1% of ethanol in water exhibit large capacitances values of 110 and 7 fF at 11 GHz, respectively. Based on the high accuracy of such characterizations, the detection of very small traces of ethanol (down to 100 ppm) can be envisioned. As far as biomedical applications are targeted, we also demonstrate the potential of fetal bovine serum detection in aqueous solution down to 5% v/v. Finally, the sensor is evaluated with living B lymphoma cells suspension in their traditional biological medium. The in-liquid microwave measurement of less than 20 living cells is successfully performed and corresponds to a capacitance contrast of 5 fF at 3 GHz relative to the reference bio-medium. For low cells concentration, the sensor response is proportional to the number of cells on the IDC, which permits to envision cells quantification and proliferation monitoring with this microwave sensing technique.

Microwave biosensor dedicated to the dielectric spectroscopy of a single alive biological cell in its culture medium

This paper presents a biosensor dedicated to the dielectric spectroscopy of a single and living biological cell in its liquid culture medium in the micro and millimeter wave ranges. This detector works in the near field and involves a capacitive gap to perform the electromagnetic sensing, while a microfluidic system has been developed and adapted to the RF circuit to precisely localize the single biological cell under study. Both capacitive and conductive contrasts of a living biological cell measured in its culture medium are accessible. A living B lymphoma cell has then been measured from 40 MHz up to 40 GHz, with a measured capacitive contrast of the order of several hundreds of attofarads.

Profiling Blood Lymphocyte Interactions with Cancer Cells Uncovers the Innate Reactivity of Human γδ T Cells to Anaplastic Large Cell Lymphoma

Quantifying the contacts that circulating lymphocytes have with cancer cells is useful, because their deficit favors malignancy progression. All normal lymphocytes contact, scan, and acquire membrane fragments (trogocytosis) from foreign cells for their immunosurveillance. So in this study, we used the in vitro trogocytosis of PKH67-stained cancer cell lines as a measure of their interactions with bulks of PBMC freshly isolated from healthy donors. Allogeneic PBMC mixed and coincubated in vitro for 1 h did not trogocytosis, whereas in the same conditions CD20+, CD4+, CD8+, γδ T, and CD16+ PBMC interacted strongly with the cancer cells. Although most unprimed lymphoid effectors of innate (NK) and adaptive (B and T) immunity from healthy donors spontaneously trogocytosed different tumoral cell lines, some carcinoma cell lines could escape them in the coculture. This also uncovered the strong interactions of circulating Vγ9/Vδ2+ central memory γδ T cells with anaplastic large cell lymphoma. These interaction profiles were stable upon time for healthy blood donors but were different with other tumors and blood donors. This profiling provides interaction signatures for the immunomonitoring of cancer.

Anti-Inflammatory Properties of Dendrimers per se

Dendrimers are polybranched and polyfunctionalized tree-like polymers. Unlike linear polymers, they have perfectly defined structure and molecular weight, due to their iterative step-by-step synthesis. Their multivalent structure and supramolecular properties have made them attractive nanotools for applications, particularly in biology and medicine. Among the different biological and medical properties of dendrimers that have been developed over the past decades, the anti-inflammatory properties of several groups of dendrimers are the most recently discovered. Thereof, dendrimers emerge as promising, although heretical, drug candidates for the treatment of still-uncured chronic inflammatory disorders. This mini-review is based on the five main scientific articles giving an overview of what can be the spectrum of anti-inflammatory characteristics displayed by dendrimers.