Peaaju difuussete astrotsütaarsete glioomide loomupärane invasiivsus

Inimese astrotsütaarsetele glioomidele iseomane invasiivne käitumine on üheks peamiseks probleemiks neuroonkoloogias. Astrotsütoomirakkude migratsioon on aluseks nende kasvajate ulatuslikule levikule närvisüsteemis, mis raskendab oluliselt kasvaja piiride kindlaksmääramist diagnostikas ning viib sageli kirurgilisele ja adjuvantravile vaatamata kasvajahaiguse retsidiveerumisele. Invasioonimehhanismide mõistmine on oluliseks ja ehk ka peamiseks eelduseks leidmaks potentsiaalseid ravistrateegilisi ründepunkte astrotsütaarse rea kasvajate efektiivseks käsitlemiseks lähitulevikus. Eesti Arst 2003; 82 (10): 699–70

A widespread viral entry mechanism : The C-end Rule motif-neuropilin receptor interaction

Many phylogenetically distant animal viruses, including the new coronavirus severe acute respiratory syndrome coronavirus 2, have surface proteins with polybasic sites that are cleaved by host furin and furin-like proteases. Other than priming certain viral surface proteins for fusion, cleavage generates a carboxy-terminal RXXR sequence. This C-end Rule (CendR) motif is known to bind to neuropilin (NRP) receptors on the cell surface. NRPs are ubiquitously expressed, pleiotropic cell surface receptors with important roles in growth factor signaling, vascular biology, and neurobiology, as well as immune homeostasis and activation. The CendR-NRP receptor interaction promotes endocytic internalization and tissue spreading of different cargo, including viral particles. We propose that the interaction between viral surface proteins and NRPs plays an underappreciated and prevalent role in the transmission and pathogenesis of diverse viruses and represents a promising broad-spectrum antiviral target.Peer reviewe

Pl1 peptide engages acidic surfaces on tumor-associated fibronectin and tenascin isoforms to trigger cellular uptake

Tumor extracellular matrix (ECM) is a high-capacity target for the precision delivery of affinity ligand-guided drugs and imaging agents. Recently, we developed a PL1 peptide (sequence: PPRRGLIKLKTS) for systemic targeting of malignant ECM. Here, we map the dynamics of PL1 binding to its receptors Fibronectin Extra Domain B (FN-EDB) and Tenascin C C-isoform (TNC-C) by computational modeling and cell-free binding studies on mutated receptor proteins, and study cellular binding and internalization of PL1 nanoparticles in cultured cells. Molecular dynamics simulation and docking analysis suggested that the engagement of PL1 peptide with both receptors is primarily driven by electrostatic interactions. Substituting acidic amino acid residues with neutral amino acids at predicted PL1 binding sites in FN-EDB (D52N-D49N-D12N) and TNC-C (D39N-D45N) resulted in the loss of binding of PL1 nanoparticles. Remarkably, PL1-functionalized nanoparticles (NPs) were not only deposited on the target ECM but bound the cells and initiated a robust cellular uptake via a pathway resembling macropinocytosis. Our studies establish the mode of engagement of the PL1 peptide with its receptors and suggest applications for intracellular delivery of nanoscale payloads. The outcomes of this work can be used for the development of PL1-derived peptides with improved stability, affinity, and specificity for precision targeting of the tumor ECM and malignant cells.Fil: Lingasamy, Prakash. University of Tartu; EstoniaFil: Põnograjeva, Kristina. University of Tartu; EstoniaFil: Kopanchuk, Sergei. University of Tartu; EstoniaFil: Tobi, Allan. University of Tartu; EstoniaFil: Rinken, Ago. University of Tartu; EstoniaFil: General, Ignacio. University of California; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Asciutto, Eliana Karina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias Físicas. - Universidad Nacional de San Martín. Instituto de Ciencias Físicas; ArgentinaFil: Teesalu, Tambet. University of Tartu; Estoni

Epithelial V-like Antigen (EVA), a Novel Member of the Immunoglobulin Superfamily, Expressed in Embryonic Epithelia with a Potential Role as Homotypic Adhesion Molecule in Thymus Histogenesis

Thymus development depends on a complex series of interactions between thymocytes and the stromal component of the organ. To identify regulated genes during this codependent developmental relationship, we have applied an RNA fingerprinting technique to the analysis of thymus expansion and maturation induced in recombinase-deficient mice injected with anti-CD3 antibodies. This approach led us to the identification of a gene encoding a new member of the immunoglobulin superfamily, named epithelial V-like antigen (EVA), which is expressed in thymus epithelium and strongly downregulated by thymocyte developmental progression. This gene is expressed in the thymus and in several epithelial structures early in embryogenesis. EVA is highly homologous to the myelin protein zero and, in thymus-derived epithelial cell lines, is poorly soluble in nonionic detergents, strongly suggesting an association to the cytoskeleton. Its capacity to mediate cell adhesion through a homophilic interaction and its selective regulation by T cell maturation might imply the participation of EVA in the earliest phases of thymus organogenesis

Tumor-penetrating peptide for systemic targeting of Tenascin-C

Extracellular matrix in solid tumors has emerged as a specific, stable, and abundant target for affinity-guided delivery of anticancer drugs. Here we describe the homing peptide that interacts with the C-isoform of Tenascin-C (TNC-C) upregulated in malignant tissues. TNC-C binding PL3 peptide (amino acid sequence: AGRGRLVR) was identified by in vitro biopanning on recombinant TNC-C. Besides TNC-C, PL3 interacts via its C-end Rule (CendR) motif with cell-and tissue penetration receptor neuropilin-1 (NRP-1). Functionalization of iron oxide nanoworms (NWs) and metallic silver nanoparticles (AgNPs) with PL3 peptide increased tropism of systemic nanoparticles towards glioblastoma (GBM) and prostate carcinoma xenograft lesions in nude mice (eight and five-fold respectively). Treatment of glioma-bearing mice with proapoptotic PL3-guided NWs improved the survival of the mice, whereas treatment with untargeted particles had no effect. PL3-coated nanoparticles were found to accumulate in TNC-C and NRP-1-positive areas in clinical tumor samples, suggesting a translational relevance. The systemic tumor-targeting properties and binding of PL3-NPs to the clinical tumor sections, suggest that the PL3 peptide may have applications as a targeting moiety for the selective delivery of imaging and therapeutic agents to solid tumors.publishedVersio

Enhancing Apoptosome Assembly via Mito-Biomimetic Lipid Nanocarrier for Cancer Therapy

Apoptosis is the natural programmed cell death process, which is responsible for abnormal cell clearance. However, many cancer cells develop various mechanisms to escape apoptosis through interrupting apoptosome assembly, which is a key step to initiate apoptosis. This promotes tumorigenesis and drug resistance, and thus, poses a great challenge in cancer treatment. Herein, a biomimetic lipid nanocarrier mimicking mitochondrial Cytochrome C (Cyt C) binding is developed. Cardiolipin, the major phospholipid of mitochondrial inner membrane, is introduced as the main component in biomimetic liposomal formulation. With the help of cardiolipin, Cyt C is sufficiently loaded in liposome based on electrostatic and hydrophobic interaction with cardiolipin. Lonidamine (LND) is added in hydrophobic phase of liposome to modulate the metabolic activity within cancer cells and sensitize the cells to Cyt C-induced apoptosis. The results suggest that LND reduces ATP level and creates favorable environment for Cyt C induced apoptosome assembly, exhibiting higher apoptosis level and anti-tumor efficacy in vitro and in vivo. The conjugation of a tumor-homing peptide, LinTT1, on the nanovesicle, increases the efficacy due to enhanced tumor accumulation. Overall, this biomimetic lipid nanocarrier proves to be an efficient delivery system with great potential of pro-apoptosis cancer therapy

LinTT1 peptide-functionalized liposomes for targeted breast cancer therapy

Breast cancer, with around 2 million new cases in 2019, is the second most common cancer worldwide and the second leading cause of cancer death among females. The aim of this work is to prepare a targeting nanoparticle through the conjugation of LinTT1 peptide, a specific molecule targeting p32 protein overexpressed by breast cancer and cancer associated cells, on liposomes' surface. This approach increases the cytotoxic effects of doxorubicin (DOX) and sorafenib (SRF) co-loaded in therapeutic liposomes on both 2D and 3D breast cancer cellular models. The liposome functionalization leads to a higher interaction with 3D breast cancer spheroids than bare ones. Moreover, interaction studies between LinTT1-functionalized liposomes and M2 primary human macrophages show an internalization of 50% of the total nanovesicles that interact with these cells, while the other 50% results only associated to cell surface. This finding suggests the possibility to use the amount of associated liposomes to enrich the hypoxic tumor area, exploiting the ability of M2 macrophages to accumulate in the central core of tumor mass. These promising results highlight the potential use of DOX and SRF co-loaded LinTT1-functionalized liposomes as nanomedicines for the treatment of breast cancer, especially in triple negative cancer cells.Peer reviewe

Hõbekuulid vähiteraapias: teel suunatud vähiravi poole

Vähiuuringute üheks keskseks eesmärgiks on vähirakke normaalsetest rakkudest eristavate ravimite väljatöötamine. Kliinilises kasutuses olevate vähiravimite puuduseks on nende vähene selektiivsus ja sellest tingitud kõrvalmõjud normaalsetes kudedes. Artiklis on antud ülevaade suunatud vähiravimite valjatöötamisest ja suundumustest. Suunatud vähiravi põhineb molekulaarsetel erinevustel vähikoe ja normaalsete veresoonte vahel. In vivo faagidisplei meetodi abil on võimalik veresoonte haigusspetsiifilisi molekulaarseid mustreid kaardistada. Selle tulemuseks on peptiidid, mis seostuvad selektiivselt vähiveresoontega. Need kullerpeptiidid nagu ka teised kasvaja veresoontega selektiivselt seonduvad molekulid (antikehad, aptameerid) võimaldavad kasvajasse viia vähiravimeid ja kontrastaineid. Hiljuti avastatud kasvajakude penetreerivad peptiidid põhjustavad vähiveresoonte selektiivset lekkimist. Koos ravimitega manustatuna põhjustavad need peptiidid ravimi väljumist kasvaja veresoontest ja tungimist kasvajakoesse – tulemuseks on ravimi terapeutilise indeksi paranemine.Eesti Arst 2015; 94(5):281–28

Targeted Delivery of Epidermal Growth Factor to the Human Placenta to Treat Fetal Growth Restriction

Placental dysfunction is the underlying cause of pregnancy complications such as fetal growth restriction (FGR) and pre-eclampsia. No therapies are available to treat a poorly functioning placenta, primarily due to the risks of adverse side effects in both the mother and the fetus resulting from systemic drug delivery. The use of targeted liposomes to selectively deliver payloads to the placenta has the potential to overcome these issues. In this study, we assessed the safety and efficacy of epidermal growth factor (EGF)-loaded, peptide-decorated liposomes to improve different aspects of placental function, using tissue from healthy control pregnancies at term, and pregnancies complicated by FGR. Phage screening identified a peptide sequence, CGPSARAPC (GPS), which selectively homed to mouse placentas in vivo, and bound to the outer syncytiotrophoblast layer of human placental explants ex vivo. GPS-decorated liposomes were prepared containing PBS or EGF (50–100 ng/mL), and placental explants were cultured with liposomes for up to 48 h. Undecorated and GPS-decorated liposomes containing PBS did not affect the basal rate of amino acid transport, human chorionic gonadotropin (hCG) release or cell turnover in placental explants from healthy controls. GPS-decorated liposomes containing EGF significantly increased amino acid transporter activity in healthy control explants, but not in placental explants from women with FGR. hCG secretion and cell turnover were unaffected by EGF delivery; however, differential activation of downstream protein kinases was observed when EGF was delivered via GPS-decorated vs. undecorated liposomes. These data indicate that targeted liposomes represent a safe and useful tool for the development of new therapies for placental dysfunction, recapitulating the effects of free EGF

Peptide-guided resiquimod-loaded lignin nanoparticles convert tumor-associated macrophages from M2 to M1 phenotype for enhanced chemotherapy

Nanomedicines represent innovative and promising alternative technologies to improve the therapeutic effects of different drugs for cancer ablation. Targeting M2-like tumor-associated macrophages (TAMs) has emerged as a favorable therapeutic approach to fight against cancer through the modulation of the tumor microenvironment. However, the immunomodulatory molecules used for this purpose present side effects upon systemic administration, which limits their clinical translation. Here, the biocompatible lignin polymer is used to prepare lignin nanoparticles (LNPs) that carry a dual agonist of the toll-like receptors TLR7/8 (resiquimod, R848). These LNPs are targeted to the CD206-positive M2-like TAMs using the “mUNO” peptide, in order to revert their pro-tumor phenotype into anti-tumor M1-like macrophages in the tumor microenvironment of an aggressive triple-negative in vivo model of breast cancer. Overall, we show that targeting the resiquimod (R848)-loaded LNPs to the M2-like macrophages, using very low doses of R848, induces a profound shift in the immune cells in the tumor microenvironment towards an anti-tumor immune state, by increasing the representation of M1-like macrophages, cytotoxic T cells, and activated dendritic cells. This effect consequently enhances the anticancer effect of the vinblastine (Vin) when co-administered with R848-loaded LNPs to the M2-like macrophages, using very low doses of R848, induces a profound shift in the immune cells in the tumor microenvironment towards an anti-tumor immune state, by increasing the representation of M1-like macrophages, cytotoxic T cells, and activated dendritic cells. This effect consequently enhances the anticancer effect of the vinblastine (Vin) when co-administered with R848-loaded LNPs. Statement of significance Lignin-based nanoparticles (LNPs) were successfully developed to target a potent TLR7/8 agonist (R848) of the tumor microenvironment (TME). This was achieved by targeting the mannose receptor (CD206) on the tumor supportive (M2-like) macrophages with the "mUNO" peptide, to reprogram them into an antitumor (M1-like) phenotype for enhanced chemotherapy. LNPs modified the biodistribution of the R848, and enhanced its accumulation and efficacy in shifting the immunological profile of the cells in the TME, which was not achieved by systemic administration of free R848. Moreover, a reduction in the tumor volumes was observed at lower equivalent doses of R848 compared with other studies. Therefore, the co-administration of R848@LNPs is a promising chemotherapeutic application in aggressive tumors, such as the triple-negative breast cancer. (c) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.Peer reviewe