Strategies for cancer gene-delivery improvement by non-viral vectors

Lack of selectivity together with severe side effects in conventional cancer treatment have afforded the devel- opment of new strategies based on gene therapy. Nowadays, gene therapy is employed through both viral and non-viral vectors. In spite of the high transfection activity of viral vectors, some drawbacks have pointed out to non-viral vectors as a safer alternative. To overcome low efficiency as well as other issues associated with the use of non-viral vectors, complexes formed by lipids and polymers with DNA, named lipoplexes and polyplexes respectively, have been modified in order to improve its features. Suitability of cancer gene therapy also requires the capacity to distinguish between normal and tumoral cells. This requirement has been solved by the addition of specific ligands that enable receptor binding and subsequent endocytosis. In this article we review the most recent approaches in structure modification of non-viral vectors through different methods comprising conjugation, addition of helper lipids or changes in design and synthesis as well as the strategy based on exploiting receptors that are usually overexpressed in malignancies. Such improvements confer specificity, efficient gene delivery, condensation, protection of DNA and low levels of toxicity avoiding off-target effects which turn into a potential tool to treat cancer

Enhanced Gene Delivery Triggered by Dual pH/Redox Responsive Host-Guest Dimerization of Cyclooligosaccharide Star Polycations

A robust strategy is reported to build perfectly monodisperse star polycationscombining a trehalose-based cyclooligosaccharide (cyclotrehalan, CT) centralcore onto which oligoethyleneimine radial arms are installed. Thearchitectural perfection of the compounds is demonstrated by a variety ofphysicochemical techniques, including NMR, MS, DLS, TEM, and GPC. Key tothe strategy is the possibility of customizing the cavity size of the macrocyclicplatform to enable/prevent the inclusion of adamantane motifs. Theseproperties can be taken into advantage to implement sequential levels ofstimuli responsiveness by combining computational design, precisionchemistry and programmed host-guest interactions. Specifically, it is shownthat supramolecular dimers implying a trimeric CT-tetraethyleneimine starpolycation and purposely designed bis-adamantane guests are preorganizedto efficiently complex plasmid DNA (pDNA) into transfection-competentnanocomplexes. The stability of the dimer species is responsive to theprotonation state of the cationic clusters, resulting in dissociation at acidicpH. This process facilitates endosomal escape, but reassembling can takeplace in the cytosol then handicapping pDNA nuclear import. By equippingthe ditopic guest with a redox-sensitive disulfide group, recapturingphenomena are prevented, resulting in drastically improved transfectionefficiencies both in vivo and in vitro.Ministerio de Ciencia e Innovación y Agencia Estatal de Investigación, de España-MCIN/AEI/10.13039/501100011033Fondo Europeo de Desarrollo Regional de la Unión Europea-RTI2018-097609-B-C21, RTI2018-097609-B-C22, PID2019-105858RB-I00 y PID2020-118384GB-I00Junta de Andalucía-P20_0016

Trifaceted Mickey Mouse Amphiphiles for Programmable Self-Assembly, DNA Complexation and Organ-Selective Gene Delivery

Instilling segregated cationic and lipophilic domains with an angular disposition in a trehalose-based trifaceted macrocyclic scaffold allows engineering patchy molecular nanoparticles leveraging directional interactions that emulate those controlling self-assembling processes in viral capsids. The resulting trilobular amphiphilic derivatives, featuring a Mickey Mouse architecture, can electrostatically interact with plasmid DNA (pDNA) and further engage in hydrophobic contacts to promote condensation into transfectious nanocomplexes. Notably, the topology and internal structure of the cyclooligosaccharide/pDNA co-assemblies can be molded by fine-tuning the valency and characteristics of the cationic and lipophilic patches, which strongly impacts the transfection efficacy in vitro and in vivo. Outstanding organ selectivities can then be programmed with no need of incorporating a biorecognizable motif in the formulation. The results provide a versatile strategy for the construction of fully synthetic and perfectly monodisperse nonviral gene delivery systems uniquely suited for optimization schemes by making cyclooligosaccharide patchiness the focus.Peer reviewe

Strategies for cancer gene-delivery improvement by non-viral vectors

Lack of selectivity together with severe side effects in conventional cancer treatment have afforded the devel- opment of new strategies based on gene therapy. Nowadays, gene therapy is employed through both viral and non-viral vectors. In spite of the high transfection activity of viral vectors, some drawbacks have pointed out to non-viral vectors as a safer alternative. To overcome low efficiency as well as other issues associated with the use of non-viral vectors, complexes formed by lipids and polymers with DNA, named lipoplexes and polyplexes respectively, have been modified in order to improve its features. Suitability of cancer gene therapy also requires the capacity to distinguish between normal and tumoral cells. This requirement has been solved by the addition of specific ligands that enable receptor binding and subsequent endocytosis. In this article we review the most recent approaches in structure modification of non-viral vectors through different methods comprising conjugation, addition of helper lipids or changes in design and synthesis as well as the strategy based on exploiting receptors that are usually overexpressed in malignancies. Such improvements confer specificity, efficient gene delivery, condensation, protection of DNA and low levels of toxicity avoiding off-target effects which turn into a potential tool to treat cancer

Trifaceted Mickey Mouse Amphiphiles for Programmable Self‐Assembly, DNA Complexation and Organ‐Selective Gene Delivery

Instilling segregated cationic and lipophilic domains with an angular disposition in a trehalose-based trifaceted macrocyclic scaffold allows engineering patchy molecular nanoparticles leveraging directional interactions that emulate those controlling self-assembling processes in viral capsids. The resulting trilobular amphiphilic derivatives, featuring a Mickey Mouse architecture, can electrostatically interact with plasmid DNA (pDNA) and further engage in hydrophobic contacts to promote condensation into transfectious nanocomplexes. Notably, the topology and internal structure of the cyclooligosaccharide/pDNA co-assemblies can be molded by fine-tuning the valency and characteristics of the cationic and lipophilic patches, which strongly impacts the transfection efficacy in vitro and in vivo. Outstanding organ selectivities can then be programmed with no need of incorporating a biorecognizable motif in the formulation. The results provide a versatile strategy for the construction of fully synthetic and perfectly monodisperse nonviral gene delivery systems uniquely suited for optimization schemes by making cyclooligosaccharide patchiness the focus.Peer reviewe

Gravest Empirical Mode to be used by Inverted Echo Sounders in order to determine the zonal flows in the South Atlantic

Four Pressure-equipped Inverted Echo Sounders (PIES) were deployed at about 10°W, between 19 and 35°S, the South Atlantic Gateway (SAGA), in order to determine the zonal flows in the South Atlantic. Those PIES will allow to observe the circulation of two water masses, the South Atlantic Central Water (SACW) and the North Atlantic Deep Water (NADW), that flow in opposite directions across the South Atlantic, between Cape town and Brazil, through the SAGA. The measurements from the PIES, together with historical hydrographic data, permit to estimate the profiles of temperature and salinity of the water column, and therefore the density. Besides, using the thermal-wind equation, it is possible to retrieve the geostrophic velocity from an array of PIES. In order to get those estimations of temperature and salinity, it is necessary to determine the Gravest Empirical Mode (GEM), a relationship between the acoustic travel time observed by the PIES and the historical observations of salinity and temperature in the study area. In this work, we will show the GEM estimated for the SAGA, calculated using historical hydrographic data from CTDs and Argo Float, as well as, the estimations of the error in the geostrophic transport

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved