ABSTRACT
The current global COVID-19 pandemic led to an unprecedented effort to develop effective vaccines against SARS-CoV-2. mRNA vaccines were developed very rapidly during the last year, and became the leading immunization platform against the virus, with highly promising phase-3 results and remarkable efficacy data. Since most animal models are not susceptible to SARS CoV-2 infection, pre-clinical studies are often limited to infection-prone animals such as hamsters and non-human primates. In these animal models, SARS-CoV-2 infection results in viral replication and a mild disease disease. Therefore, the protective efficacy of the vaccine in these animals is commonly evaluated by its ability to elicit immunologic responses, diminish viral replication and prevent weight loss. Our lab recently reported the design of a SARS-CoV-2 human Fc-conjugated receptor-binding domain (RBD-hFc) mRNA vaccine delivered via lipid nanoparticles (LNPs). These experiments demonstrated the development of a robust and specific immunologic response in RBD-hFc mRNA-vaccinated BALB/c mice. In the current study, we evaluated the protective effect of this RBD-hFc mRNA vaccine by employing the K18-hACE2 mouse model. We report that administration of RBD-hFc mRNA vaccine to K18-hACE2 mice led to a robust humoral response comprised of both binding and neutralizing antibodies. In accordance with the recorded immunologic immune response, 70% of vaccinated mice were protected against a lethal dose (3000 plaque forming units) of SARS-CoV-2, while all control animals succumbed to infection. To the best of our knowledge, this is the first non-replicating mRNA vaccine study reporting protection of K18-hACE2 against a lethal SARS-CoV-2 infection.
ABSTRACT
Etoposide phosphate (EP), a water-soluble anticancer prodrug, is widely used for treatment of many cancers. After administration it is rapidly converted to etoposide, its parent compound, which exhibits anticancer activity. Difficulty in parenteral administration necessitates the development of a suitable nanoparticle delivery system for EP. Here we have used indium both as a carrier to deliver etoposide phosphate to tumor cells and as a SPECT imaging agent through incorporation of (111)In. Etoposide phosphate was successfully encapsulated together with indium in nanoparticles, and exhibited dose dependent cytotoxicity and induction of apoptosis in cultured H460 cancer cells via G2/M cell cycle arrest. In a mouse xenograft lung cancer model, etoposide phosphate/indium nanoparticles induce tumor cell apoptosis, leading to significant enhancement of tumor growth inhibition compared to the free drug.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Etoposide/analogs & derivatives , Indium , Lung Neoplasms , Nanoparticles/chemistry , Organophosphorus Compounds , Theranostic Nanomedicine/methods , Animals , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/metabolism , Carcinoma, Non-Small-Cell Lung/pathology , Drug Carriers , Etoposide/chemistry , Etoposide/pharmacology , G2 Phase Cell Cycle Checkpoints/drug effects , Humans , Indium/chemistry , Indium/pharmacology , Lung Neoplasms/drug therapy , Lung Neoplasms/metabolism , Lung Neoplasms/pathology , M Phase Cell Cycle Checkpoints/drug effects , Mice , Mice, Nude , Organophosphorus Compounds/chemistry , Organophosphorus Compounds/pharmacology , Xenograft Model Antitumor AssaysABSTRACT
Dendritic cells (DCs) pulsed/transduced with tumor-associated or viral antigens have shown promise in combating cancer and infectious diseases. Despite significant progresses, development of a biologically safe DC-based genetic immunization (DNA vaccination) system capable of providing truly long-lasting protective immunity remains a significant scientific challenge. Here we show that immunization with autologous DCs pre-transfected with electrostatic complexes (lipoplexes) of a plasmid DNA encoding melanoma tumor associated antigen and liposomes of two lysinylated cationic amphiphiles with mannose-mimicking quinic and shikimic acid head-groups provides long-lasting (300 days post tumor challenge) protective immunity with significant memory response (more than six months after the second tumor challenge) in more than 80% immunized mice. The presently described non-viral ex vivo DC-transfection system may be exploited in inducing long-lasting immune response in DC-based genetic immunization.
Subject(s)
Dendritic Cells/immunology , Mannose/chemistry , Melanoma/immunology , Transfection/methods , Vaccines, DNA/chemistry , Vaccines, DNA/therapeutic use , Animals , Antigen-Presenting Cells/immunology , Antigen-Presenting Cells/metabolism , Cell Line, Tumor , Cells, Cultured , Dendritic Cells/metabolism , Flow Cytometry , Interferon-gamma/metabolism , Interleukin-4/metabolism , Male , Melanoma/metabolism , Melanoma/prevention & control , Mice , Mice, Inbred C57BLABSTRACT
Mannosylated cationic vectors have been previously used for delivering DNA vaccines to antigen presenting cells (APCs) via mannose receptors expressed on the cell surface of APCs. Here we show that cationic amphiphiles containing mannose-mimicking quinic acid and shikimic acid headgroups deliver genes to APCs via mannose receptor. Cationic amphiphile with shikimic acid headgroup was more efficacious than its mannosyl counterpart in combating mouse tumor growth by dendritic cell (the most professional APC) based genetic immunization.
Subject(s)
Cations/chemistry , Dendritic Cells/metabolism , Mannose/chemistry , Mannose/pharmacology , Melanoma, Experimental/drug therapy , Shikimic Acid/chemistry , Vaccines, DNA/administration & dosage , Animals , Antigen-Presenting Cells , Cells, Cultured , Enzyme-Linked Immunosorbent Assay , Female , Immunization , Lectins, C-Type/metabolism , Liposomes , Mannose/chemical synthesis , Mannose Receptor , Mannose-Binding Lectins/metabolism , Mass Spectrometry , Mice , Mice, Inbred C57BL , NIH 3T3 Cells , Receptors, Cell Surface/metabolismABSTRACT
The clinical success of gene therapy critically depends on the use of efficient and safe gene delivery reagents. The present tutorial review is aimed at inspiring young researchers and students to take up the unsolved challenges in using cationic amphiphiles as safe gene transfer reagents. The review highlights important structure-activity studies in the field to date including the use of cationic amphiphiles for receptor specific targeted gene therapy and for delivery of siRNAs in the emerging field of RNA interference.
