Increasing vaccine potency through exosome antigen targeting.

While many tumor associated antigens (TAAs) have been identified in human cancers, efforts to develop efficient TAA "cancer vaccines" using classical vaccine approaches have been largely ineffective. Recently, a process to specifically target proteins to exosomes has been established which takes advantage of the ability of the factor V like C1C2 domain of lactadherin to specifically address proteins to exosomes. Using this approach, we hypothesized that TAAs could be targeted to exosomes to potentially increase their immunogenicity, as exosomes have been demonstrated to traffic to antigen presenting cells (APC).

Targeting tumor antigens to secreted membrane vesicles in vivo induces efficient antitumor immune responses.

Expression of non-self antigens by tumors can induce activation of T cells in vivo, although this activation can lead to either immunity or tolerance. CD8+ T-cell activation can be direct (if the tumor expresses MHC class I molecules) or indirect (after the capture and cross-presentation of tumor antigens by dendritic cells). The modes of tumor antigen capture by dendritic cells in vivo remain unclear.

Exosomes as novel therapeutic nanodevices.

Exosomes are small vesicles (60 to 100 nm) that are released by many cell types. Their heterogeneous protein and lipid compositions, in addition to their enduring physicochemical features have led to the idea of using these natural vesicles as nanodevices for the development of new therapeutic applications. The first exosome-based nanodevices evaluated in the clinic consisted of autologous dexosomes (patient-specific exosomes released by dendritic cells and loaded with tumor antigen-derived peptides).

Exosome Display technology: applications to the development of new diagnostics and therapeutics.

Exosome Display is a novel methodology enabling the manipulation of exosome protein content. This technology stems from the identification of addressing domains that mediate the specific distribution of proteins on exosomes. More particularly, Lactadherin expressed in non-mammary gland tissue has been found to localize to exosomes via binding of its C1C2 domain to exosome lipids.

An analysis of variability in the manufacturing of dexosomes: implications for development of an autologous therapy.

Dexosomes are nanometer-size vesicles released by dendritic-cells, possessing much of the cellular machinery required to stimulate an immune response (i.e. MHC Class I and II).

Dexosomes as a therapeutic cancer vaccine: from bench to bedside.

Exosomes released from dendritic cells, now referred as dexosomes, have recently been extensively characterized. Preclinical studies in mice have shown that, when properly loaded with tumor antigens, dexosomes can elicit a strong antitumor activity. Before dexosomes could be used in humans as a therapeutic vaccine, extensive development work had to be performed to meet the present regulatory requirements.

Dendritic cell-derived exosomes in cancer immunotherapy: exploiting nature's antigen delivery pathway.

Dendritic cells release large quantities of exosomes, known as dexosomes. These dexosomes are heat-stable, small vesicles (60-90 nm in diameter) made up of a lipid bilayer displaying an enrichment in sphingomyelin and a decrease in phosphatidylcholine content with no measurable asymmetry. They incorporate a characteristic set of proteins, including a large quantity of tetraspanins such as CD9 and CD81, all the known antigen presenting molecules (major histocompatibility complex class I and II, CD1 a, b, c and d) and the costimulatory molecule CD86.

Vaccination of metastatic melanoma patients with autologous dendritic cell (DC) derived-exosomes: results of thefirst phase I clinical trial.

BACKGROUND: DC derived-exosomes are nanomeric vesicles harboring functional MHC/peptide complexes capable of promoting T cell immune responses and tumor rejection. Here we report the feasability and safety of the first Phase I clinical trial using autologous exosomes pulsed with MAGE 3 peptides for the immunization of stage III/IV melanoma patients. Secondary endpoints were the monitoring of T cell responses and the clinical outcome.

A phase I study of dexosome immunotherapy in patients with advanced non-small cell lung cancer.

BACKGROUND: There is a continued need to develop more effective cancer immunotherapy strategies. Exosomes, cell-derived lipid vesicles that express high levels of a narrow spectrum of cell proteins represent a novel platform for delivering high levels of antigen in conjunction with costimulatory molecules. We performed this study to test the safety, feasibility and efficacy of autologous dendritic cell (DC)-derived exosomes (DEX) loaded with the MAGE tumor antigens in patients with non-small cell lung cancer (NSCLC).

Exosomes as a tumor vaccine: enhancing potency through direct loading of antigenic peptides.

Exosomes secreted by dendritic cells (DCs) contain MHC-I, MHC-II, and other accessory molecules required for antigen presentation to T cells. Previous studies have shown that exosome MHC-I "indirectly" loaded by adding peptides to DC cultures are immunogenic. However, analysis of peptide binding was not performed to link T-cell-stimulating activity with the amount of MHC-I/peptide complexes on the exosomes.

Production and characterization of clinical grade exosomes derived from dendritic cells.

We describe methods for the production, purification, and characterization of clinical grade (cGMP) exosomes derived from antigen presenting cells (APCs). Exosomes have been shown to have immunotherapeutic properties through their presentation of biologically relevant antigens [Nat. Med.

Another link between phospholipid transmembrane migration and ABC transporter gene family, inferred from a rare inherited disorder of phosphatidylserine externalization.

The mechanisms involved in the maintenance or loss of the asymmetric distribution of phospholipids in the cell plasma membrane remain mysterious. In the yeast Saccharomyces cerevisiae, the transmembrane migration of certain phospholipids is controlled by transcription regulators of various ATP-binding cassette (ABC) transporters. The P-glycoprotein membrane transporters encoded by the multidrug resistance (MDR) genes, members of the ABC protein family, act as lipid translocases in mammalian cells.

Betulinic acid derivatives: a new class of specific inhibitors of human immunodeficiency virus type 1 entry.

A novel series of omega-aminoalkanoic acid derivatives of betulinic acid were synthesized and evaluated for their activity against human immunodeficiency virus (HIV). The anti-HIV-1 activity of several members of this new series was found to be in the nanomolar range in CEM 4 and MT-4 cell cultures. The optimization of the omega-aminoalkanoic acid side chain is described.

Betulinic acid derivatives: a new class of human immunodeficiency virus type 1 specific inhibitors with a new mode of action.

A series of omega-undecanoic amides of lup-20(29)-en-28-oic acid derivatives were synthesized and evaluated for activity in CEM 4 and MT-4 cell cultures against human immunodeficiency virus type 1 (HIV-1) strain IIIB/LAI. The potent HIV inhibitors which emerged, compounds 5a, 16a, and 17b, were all derivatives of betulinic acid (3beta-hydroxylup-20(29)-en-28-oic acid). No activity was found against HIV-2 strain ROD.

Binding of the Escherichia coli UvrAB proteins to the DNA mono- and diadducts of cis-[N-2-amino-N-2-methylamino-2,2,1-bicycloheptane]dichloroplatinum(II ) and cisplatin. Analysis of the factors controlling recognition and proof of monoadduct-mediated UvrB-DNA cross-linking.

The interactions of the Escherichia coli endonuclease UvrAB proteins with the DNA mono- and diadducts of both the cis-racemic exo-[N-2-amino-N-2-methylamino-2,2,1-bicycloheptane]dichloroplatin um(II) (complex 1) and cisplatin (cis-diamminedichloroplatinum(II) (cis-DDP)), have been studied. Complex 1 reacts faster with DNA than cis-DDP and gives monoadducts with a longer lifetime (8 h 20 min chelation t 1/2 compared with 2 h 40 min for cis-DDP). Using pSP65 plasmid [3H]DNA, the filter binding assay was associated with the analysis of the nucleoprotein complexes to characterize the UvrAB recognition of the platinum adducts and to demonstrate the occurrence of platinum-mediated DNA-protein cross-linking.

Asymmetrically substituted ethylenediamine platinum(II) complexes as antitumor agents: synthesis and structure-activity relationships.

A series of platinum dichloroethylenediamine complexes [PtCl2(R-en)] bearing a side chain on one carbon atom of the ethylenediamine ligand, with or without a functional group on the side chain, have been prepared and investigated for antitumor activity against L1210 leukemia. They were tested both in vitro, with cisplatin-sensitive and resistant cell lines, and in vivo, with cisplatin-sensitive and resistant tumors grafted i.p.

Structure-activity relationships in a series of 5-[(2,5-dihydroxybenzyl)amino]salicylate inhibitors of EGF-receptor-associated tyrosine kinase: importance of additional hydrophobic aromatic interactions.

Potent inhibitors of EGF-dependent protein tyrosine kinase (PTK) activity were synthesized in a series of 5-[(2,5-dihydroxybenzyl)amino]salicylates. Several of these compounds inhibited EGF-dependent DNA synthesis in ER 22 cells with IC50 < 1 microM. In this series of PTK inhibitors, the role of the salicylate moiety as a potential divalent ion chelator was tested and found to be nonessential in all cases.

Synthesis and biological activity of new dimers in the 7H-pyrido[4,3-c] carbazole antitumor series.

Ditercalinium (NSC 366241) is a 7H-pyrido[4,3-c]carbazole dimer with a diethylbipiperidine rigid chain linking the two heterocyclic rings. Ditercalinium is characterized by a high DNA affinity and bisintercalating ability, associated with potent antitumor properties, involving an original mechanism of action. Unfortunately as ditercalinium is hepatotoxic, its clinical evaluation has been interrupted.

Removal of DNA curving by DNA ligands: gel electrophoresis study.

The removal of inherent curving in Crithidia fasciculata kinetoplast DNA by various small DNA ligands, groove binders and mono- and bisintercalators, has been studied by gel retardation and electron microscopy. The migration of the kinetoplast DNA fragment is highly retarded during gel electrophoresis. We demonstrate that this retardation is suppressed by DNA ligands such as distamycin and ditercalinium, which have different modes of binding and sequence specificities.

[Genomic pharmacology].

The aim of genomic pharmacology is to discover substances able to influence the expression of specific genes. These substances could be used in many pathologies in which the expression of specific genes is abnormal and in the control of viral infection. The potential targets of genomic pharmacology may be classified in two groups: first, the proteins regulating genetic expression, and, second, the nucleic acids which carry the genetic information.

Comparative cytotoxicities of a series of ellipticine and olivacine derivatives on multidrug resistant cells of human and murine origins.

The MDR P-glycoprotein has been described as a major factor of multidrug resistance. This transmembrane glycoprotein acts like an energy dependent efflux pump which possesses a broad specificity. It seems to be acting as a pump requiring drug fixation prior to extrusion.

DNase I susceptibility of bent DNA and its alteration by ditercalinium and distamycin.

The bending of kinetoplast DNA from Crithidia fasciculata is thought to be related to the periodic distribution of AA or TT cluster sequences. The sensitivity to DNase I of the two strands of this DNA was analyzed at nucleotide resolution by sequencing gel electrophoresis. The effect on the DNase I cleavage pattern of two drugs, ditercalinium and distamycin, that are able to remove bending was analyzed.

Interaction of cationic porphyrins with DNA: importance of the number and position of the charges and minimum structural requirements for intercalation.

Thirty-three porphyrins or metalloporphyrins corresponding to the general formula [meso-[N-methyl-4(or 3 or 2)-pyridiniumyl]n(aryl)4-nporphyrin]M (M = H2, CuII, or ClFeIII), with n = 2-4, have been synthesized and characterized by UV-visible and 1H NMR spectroscopy and mass spectrometry. These porphyrins differ not only in the number (2-4) and position of their cationic charges but also in the steric requirements to reach even temporarily a completely planar geometry. In particular, they contain 0, 1, 2, 3, or 4 meso-aryl substituents not able to rotate.