Chemical warfare | EPFL Graph Search

Chemical warfare (CW) involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from nuclear warfare, biological warfare and radiological warfare, which together make up CBRN, the military acronym for chemical, biological, radiological, and nuclear (warfare or weapons), all of which are considered "weapons of mass destruction" (WMDs), a term that contrasts with conventional weapons. The use of chemical weapons is prohibited under customary international humanitarian law. Definition Chemical warfare is different from the use of conventional weapons or nuclear weapons because the destructive effects of chemical weapons are not primarily due to any explosive force. The offensive use of living organisms (such as anthrax) is considered biological warfare rather than chemical warfare; however, the use of nonliving toxic products produced by living organisms (e.g. toxins such as botulinum toxin, ricin, and saxitoxin) is considered che

Thrombosis efficacy induced by photodynamic therapy using different photosensitizers

Bernadette Pegaz-Toquet

Various human pathologies, such as cancers or, notably, exudative age-related macular degeneration (AMD), are characterized by an abnormal vascular proliferation (angiogenesis), which in the case of this type of AMD, can rapidly lead to blindness if no countermeasures are taken. In the past few years, it has become possible to stop - or at least to notably slow down - the evolution of AMD, by applying treatments based on photodynamic therapy (PDT), whereby, through the action of a molecule acting as photosensitizer (PS) which is targeted preferentially to the choroidal neovessels (CNV), the effects of this abnormal angiogenesis are stopped by provoking the closure of the neovessels. In particular, the PDT group at EPF-Lausanne has, in the past, already tested on the model of the chick embryo chorioallantoic membrane (known as the CAM model) several PSs of potential interest as substitute to the product currently considered as standard (Visudyne® , itself co-developed in this group) for the treatment of the CNV associated with AMD. The aim of this thesis was to study new molecules and/or formulations, potentially suitable as substitutes to the current photodynamic treatment of AMD, while diminishing its negative side-effects: general phototoxicity due to diffusion of the product out of the vasculature and further lack of selectivity leading to (undesirable) partial occlusion of the normal vasculature. In order to enable extrapolation and comparison of the results obtained, we have focused our attention on vascular effects only and administered the tested PSs under essentially similar conditions (formulation in DMSO; same delivery system through biodegradable nanoparticles built with the same polymer). In addition, the same animal model (the CAM model) was used throughout the entire study, the formulations being administered by intravenous injection. This model, importantly, allows for an easy and real-time semi-quantitative visualisation and recording of the vascular effects of a PS induced during a PDT session. In the first part of this work, we demonstrate that the tetra-phenylporphyrin molecule, when formulated in nanoparticles based on poly(D, L - lactic acid, of well defined size (ca. 200 nm or less) is a very interesting PS-candidate potentially suitable as a replacement of the currently used one. We show that inclusion of this PS in nanoparticles notably reduces the PDT's general phototoxicity. We believe therefore that this PS would deserve more thorough pre-clinical studies, on an animal model closer to the human case (for example, Ryan's model). The second part of this thesis aimed at elaborating a strategy allowing, in due time, for an improved selectivity of occlusion of the neovasculature, said strategy aiming at an active targeting of neovessels. Recently, a number of possible biochemical targets have been identified, including the so-called ανβ3 receptors, which are highly expressed at the level of the neovessels' endothelial cells. Our approach consisted in coupling a fluorescent molecule (fluorescein, easily visualized by epi-microscopy) to a protein (a kistrin) which contains the RGD peptide sequence, known for its affinity for the ανβ3 receptors. We have thus been able to demonstrate that the kistrin was effectively linked to these receptors and, therefore, that active targeting of the neovessels had indeed taken place. A complete proof of this concept by realizing the coupling of this kistrin with a PS molecule will be the next step in this research.

EPFL2007

Mechanical Immunoengineering of T Cells for Enhanced Cancer Immunotherapy

Kewen Lei

Cancer is one of the leading causes of death globally. Immunotherapy represents one of the most promising cancer treatments inducing complete and durable responses in a fraction of cancer patients. Despite the unprecedented clinical success achieved by T cell-based cancer immunotherapies, there are tremendous outstanding challenges, including low response rate and severe toxicities, which substantially limit the clinical benefits in a majority of cancer patients. At present, enormous efforts have been spent on modulating biochemical interactions for improving the efficacy and safety of T cell-based cancer immunotherapy. Besides biochemical exchanges, mechanical interactions are universal in every step of T cell immunity and are crucial in regulating T cell functions. Thus, immunoengineering approaches that modulate mechanical interactions in T cell immunity hold great promise to improve current cancer immunotherapy. This thesis aims to develop novel mechanical immunoengineering approaches for improving cancer immunotherapy. Specifically, it includes the following parts:Developing a spiky artificial antigen-presenting cell (aAPC) to enhance ex vivo T cell expansion. Ex vivo expansion of T cells is critical in adoptive T cell therapy (ACT) to ensure an effective therapeutic dosage for cancer treatment. By mimicking the dendritic morphology of dendritic cells, I developed a spiky TiO2 microparticle presenting T cell stimulatory ligands as an aAPC to enhance ex vivo T cell expansion. The spiky aAPC outperformed the smooth counterpart, as well as Dynabead®, a standard aAPC used in clinical manufacturing of ACT therapy, for T cell activation and expansion depending on F-actin polymerization in T cells. Therefore, this finding identifies the morphology of aAPCs as a critical parameter to improve ex vivo T cell manufacturing for ACT therapy.Boosting T cell-mediated cytotoxicity by stiffening cancer cells. I discovered that cancer cell softening derived from cholesterol enrichment in the plasma membrane led to resistance to T cell-mediated cytotoxicity. Stiffening cancer cells via membrane cholesterol depletion substantially enhanced T cell-mediated cytotoxicity against cancer cells through augmenting T cell mechanical force but not any known biochemical pathways of T cell-mediated cytotoxicity. Cancer cell stiffening intervention in vivo enhanced the efficacy of ACT therapy in multiple preclinical solid tumor models. Cancer cell softness thus represents a new immune checkpoint of mechanical basis, and therapeutically targeting this mechanical immune checkpoint has the potential to improve the clinical response of T cell-based cancer immunotherapy.Utilizing T cell force as a trigger to achieve specific release of anti-cancer drugs. Specific delivery of T cell supporting drugs and/or anti-cancer drugs into tumors has the potential to increase the response rate of ACT therapy without causing systemic toxicity. To this end, I developed a T cell force-responsive drug release system based on a mesoporous silica microparticle with DNA force sensors as gatekeepers. T cell force as a highly specific signal upon recognizing cancer cells presenting cognate antigens was shown to trigger specific drug release when T cell receptor signaling was activated. Further, the T cell force-responsive drug release system could deliver anti-cancer drugs in vitro and in vivo in a T cell force-dependent manner and holds promise to enhance cancer immunotherapy.

EPFL2022

Glucose transporters in cancer - from tumor cells to the tumor microenvironment

Pierre-Benoit Bernard Ancey, Caroline Anne-Lyse Contat, Etienne Meylan

Solute carriers of the glucose transporter (GLUT) family mediate the first step for cellular glucose usage. The upregulation of GLUTs has been reported in numerous cancer types as a result of perturbation of gene expression or protein relocalization or stabilization. Because they enable to sustain the energy demand required by tumor cells for various biochemical programs, they are promising targets for the development of anticancer strategies. Recently, important biological insights have come from the fine crystal structure determination of several GLUTs; these advances will likely catalyze the development of new selective inhibitory compounds. Furthermore, deregulated glucose metabolism of nontumor cells in the tumor mass is beginning to be appreciated and could have major implications for our understanding of how glucose uptake by specific cell types influences the behavior of neighboring cells in the same microenvironment. In this review, we discuss some of the deregulation mechanisms of glucose transporters, their genetic and pharmacological targeting in cancer, and new functions they may have in nontumor cells of the tumor environment or beyond glucose uptake for glycolysis.