Mass Spectrometry-Based Workflow for the Identification and Quantification of Alternative and Canonical Proteins in Pancreatic Cancer Cells.

The identification of small proteins and proteins produced from unannotated open reading frames (called alternative proteins or AltProts) has changed our vision of the proteome and has attracted more and more attention from the scientific community. Despite several studies investigating particular AltProts in diseases and demonstrating their importance in such context, we are still missing data on their expression and functions in many pathologies. Among these, pancreatic ductal adenocarcinoma (PDAC) is a particularly relevant case to study alternative proteins.

IL-33-primed human mast cells drive IL-9 production by CD4 effector T cells in an OX40L-dependent manner.

Interleukin-33 (IL-33) is an alarmin released by epithelial cells in response to tissue damage. It activates resident immune sentinel cells, which then produce signals commonly associated with type 2 immune responses, particularly affecting infiltrating antigen-specific T cells. Given that mast cells (MCs) are a primary target of IL-33 and can shape T helper (Th) cell responses, we investigated the effect of IL-33 priming on the ability of MCs to influence Th cell cytokine production.

Overexpression of Growth Differentiation Factor 15 in Glioblastoma Stem Cells Promotes Their Radioresistance.

GSCs play an important role in GBM recurrence. Understanding the resistance mechanisms in these cells is therefore crucial for radiation therapy optimization. In this study, using patient-derived GSCs, we demonstrate that GDF15, a cytokine belonging to the TGF-β superfamily, is regulated by irradiation (IR) and the transcription factor WWTR1/TAZ.

Polo-like kinase 1 regulates immune synapse assembly and cytotoxic T cell function by driving microtubule dynamics.

Elimination of virally infected or tumoral cells is mediated by cytotoxic T cells (CTL). Upon antigen recognition, CTLs assemble a specialized signaling and secretory domain at the interface with their target, the immune synapse (IS). During IS formation, CTLs acquire a transient polarity, marked by re-orientation of the centrosome and microtubule cytoskeleton toward the IS, thus directing the transport and delivery of the lytic granules to the target cell.

Evolutionary design of explainable algorithms for biomedical image segmentation.

An unresolved issue in contemporary biomedicine is the overwhelming number and diversity of complex images that require annotation, analysis and interpretation. Recent advances in Deep Learning have revolutionized the field of computer vision, creating algorithms that compete with human experts in image segmentation tasks. However, these frameworks require large human-annotated datasets for training and the resulting "black box" models are difficult to interpret.

Visualizing the subcellular localization of RHOB-GTP and GTPase-Effector complexes using a split-GFP/nanobody labelling assay.

Small GTPases are highly regulated proteins that control essential signaling pathways through the activity of their effector proteins. Among the RHOA subfamily, RHOB regulates peculiar functions that could be associated with the control of the endocytic trafficking of signaling proteins. Here, we used an optimized assay based on tripartite split-GFP complementation to localize GTPase-effector complexes with high-resolution.

PPARγ activation modulates the balance of peritoneal macrophage populations to suppress ovarian tumor growth and tumor-induced immunosuppression.

Background: Ovarian adenocarcinoma (OVAD) frequently metastasizes to the peritoneal cavity and manifests by the formation of ascites, which constitutes a tumor-promoting microenvironment. In the peritoneal cavity, two developmentally, phenotypically and functionally distinct macrophage subsets, immunocompetent large peritoneal macrophages (LPM) and immunosuppressive small peritoneal macrophages (SPM), coexist. Because peroxisome proliferator-activated receptor γ (PPARγ) is a critical factor participating in macrophage differentiation and cooperates with CCAAT/enhancer binding protein β (C/EBPβ), a transcription factor essential for SPM-to-LPM differentiation, PPARγ could be also involved in the regulation of SPM/LPM balance and could be a promising therapeutic target.

Hypofractionated Stereotactic Re-irradiation and Anti-PDL1 Durvalumab Combination in Recurrent Glioblastoma: STERIMGLI Phase I Results.

Background: Hypofractionated stereotactic radiotherapy (hFSRT) is a salvage option for recurrent glioblastoma (GB) which may synergize anti-PDL1 treatment. This phase I study evaluated the safety and the recommended phase II dose of anti-PDL1 durvalumab combined with hFSRT in patients with recurrent GB.

Methods: Patients were treated with 24 Gy, 8 Gy per fraction on days 1, 3, and 5 combined with the first 1500 mg Durvalumab dose on day 5, followed by infusions q4weeks until progression or for a maximum of 12 months.

Measuring CTL Lytic Granule Secretion and Target Cell Membrane Repair by Fluorescent Lipophilic Dye Uptake at the Lytic Synapse.

CD8 cytotoxic T lymphocytes (CTL) play a key role in anti-tumor immune response. They are therefore at the heart of current immunotherapy protocols against cancer. Despite current strategies to potentiate CTL responses, cancer cells can resist CTL attack, thus limiting the efficacy of immunotherapies.

SK2 channels set a signalling hub bolstering CAF-triggered tumourigenic processes in pancreatic cancer.

Objective: Intercellular communication within pancreatic ductal adenocarcinoma (PDAC) dramatically contributes to metastatic processes. The underlying mechanisms are poorly understood, resulting in a lack of targeted therapy to counteract stromal-induced cancer cell aggressiveness. Here, we investigated whether ion channels, which remain understudied in cancer biology, contribute to intercellular communication in PDAC.

Resisting T cell attack: tumor-cell-intrinsic defense and reparation mechanisms.

Cytotoxic T lymphocytes (CTLs) are antigen-specific killer cells equipped to identify and eliminate host cells that have been altered through infection or transformation. Both chimeric antigen-receptor (CAR) T cell therapies and immune checkpoint blockade (ICB) therapies are based on successful elimination of tumor cells by cytotoxic effectors. In this opinion article, we outline cell-intrinsic mechanisms by which tumor cells defend against CTLs, highlighting pathways that confer resistance and proposing opportunities for combination therapies.

Human septins organize as octamer-based filaments and mediate actin-membrane anchoring in cells.

Septins are cytoskeletal proteins conserved from algae and protists to mammals. A unique feature of septins is their presence as heteromeric complexes that polymerize into filaments in solution and on lipid membranes. Although animal septins associate extensively with actin-based structures in cells, whether septins organize as filaments in cells and if septin organization impacts septin function is not known.

Learning from TCR Signaling and Immunological Synapse Assembly to Build New Chimeric Antigen Receptors (CARs).

Chimeric antigen receptor (CAR) T cell immunotherapy is a revolutionary pillar in cancer treatment. Clinical experience has shown remarkable successes in the treatment of certain hematological malignancies but only limited efficacy against B cell chronic lymphocytic leukemia (CLL) and other cancer types, especially solid tumors. A wide range of engineering strategies have been employed to overcome the limitations of CAR T cell therapy.

Translational alterations in pancreatic cancer: a central role for the integrated stress response.

mRNA translation is a key mechanism for cancer cell proliferation and stress adaptation. Regulation of this machinery implicates upstream pathways such as PI3K/AKT/mTOR, RAS/MEK/ERK and the integrated stress response (ISR), principally coordinating the translation initiation step. During the last decade, dysregulation of the mRNA translation process in pancreatic cancer has been widely reported, and shown to critically impact on cancer initiation, development and survival.

Tripartite split-GFP assay to identify selective intracellular nanobody that suppresses GTPase RHOA subfamily downstream signaling.

Strategies based on intracellular expression of artificial binding domains present several advantages over manipulating nucleic acid expression or the use of small molecule inhibitors. Intracellularly-functional nanobodies can be considered as promising macrodrugs to study key signaling pathways by interfering with protein-protein interactions. With the aim of studying the RAS-related small GTPase RHOA family, we previously isolated, from a synthetic phage display library, nanobodies selective towards the GTP-bound conformation of RHOA subfamily proteins that lack selectivity between the highly conserved RHOA-like and RAC subfamilies of GTPases.

Epicutaneous allergen immunotherapy induces a profound and selective modulation in skin dendritic-cell subsets.

Background: Epicutaneous immunotherapy (EPIT) protocols have recently been developed to restore tolerance in patients with food allergy. The mechanisms by which EPIT protocols promote desensitization rely on a profound immune deviation of pathogenic T- and B-cell responses.

Objective: To date, little is known about the contribution of skin dendritic cells (skDCs) to T-cell remodeling and EPIT efficacy.

: How Tumor Cells Defend Against the Siege Weapons of Cytotoxic T Lymphocytes.

CD8 cytotoxic T lymphocytes (CTLs) are the main cellular effectors of the adaptive immune response against cancer cells, which in turn have evolved sophisticated cellular defense mechanisms to withstand CTL attack. Herein we provide a critical review of the pertinent literature on early and late attack/defense events taking place at the CTL/target cell lytic synapse. We examine the earliest steps of CTL-mediated cytotoxicity ("the poison arrows") elicited within seconds of CTL/target cell encounter, which face commensurately rapid synaptic repair mechanisms on the tumor cell side, providing the first formidable barrier to CTL attack.

Phenotypic and Histological Distribution Analysis Identify Mast Cell Heterogeneity in Non-Small Cell Lung Cancer.

Mast cells (MCs) are multifaceted innate immune cells often present in the tumor microenvironment (TME). However, MCs have been only barely characterized in studies focusing on global immune infiltrate phenotyping. Consequently, their role in cancer is still poorly understood.

Ultrarapid lytic granule release from CTLs activates Ca-dependent synaptic resistance pathways in melanoma cells.

Human cytotoxic T lymphocytes (CTLs) exhibit ultrarapid lytic granule secretion, but whether melanoma cells mobilize defense mechanisms with commensurate rapidity remains unknown. We used single-cell time-lapse microscopy to offer high spatiotemporal resolution analyses of subcellular events in melanoma cells upon CTL attack. Target cell perforation initiated an intracellular Ca wave that propagated outward from the synapse within milliseconds and triggered lysosomal mobilization to the synapse, facilitating membrane repair and conferring resistance to CTL induced cytotoxicity.

IL-17 Mast Cell/T Helper Cell Axis in the Early Stages of Acne.

Acne is a multifactorial disease driven by physiological changes occurring during puberty in the pilosebaceous unit (PSU) that leads to sebum overproduction and a dysbiosis involving notably . These changes in the PSU microenvironment lead to a shift from a homeostatic to an inflammatory state. Indeed, immunohistochemical analyses have revealed that inflammation and lymphocyte infiltration can be detected even in the infraclinical acneic stages, highlighting the importance of the early stages of the disease.