DNA origami systems could be important candidates for clinical applications. Unfortunately, their intrinsic properties such as the activation of non-specific immune system responses leading to inflammation, instability in physiological solutions, and a short in vivo lifetime are the major challenges for real world applications. A compact short tube DNA origami (STDO) of 30 nm in length and 10 nm in width was designed to fit inside the core of a stealth liposome (LSTDO) of about 150 nm to remote load doxorubicin. Biocompatibility was tested in three-dimensional (3D) organoid cultures and in vivo. Efficacy was evaluated in different cell lines and in a xenograft breast cancer mouse model. As described in a previous work, LSTDO is highly stable and biocompatible, escaping the recognition of the immune system. Here we show that LSTDO have an increased toleration in mouse liver organoids used as an ex vivo model that recapitulate the tissue of origin. This innovative drug delivery system (DDS) improves the antitumoral efficacy and biodistribution of doxorubicin in tumor-bearing mice and decreases bone marrow toxicity. Our application is an attractive system for the remote loading of other drugs able to interact with DNA for the preparation of liposomal formulations.

Although glucose is one of the most important physio-pathological substrates of aldose reductase, it is not an easy molecule for in vitro investigation into the enzyme. In many cases alternative aldoses have been used for kinetic characterization and inhibition studies. However these molecules do not completely match the structural features of glucose, thus possibly leading to results that are not fully applicable to glucose. We show how aldose reductase is able to act efficiently on L-idose, the C-5 epimer of D-glucose. This is verified using both the bovine lens and the human recombinant enzymes. While the kcat values obtained are essentially identical to those measured for D-glucose, a significant decrease in KM was observed. This can be due to the significantly higher level of the free aldehyde form present in L-idose compared to D-glucose. We believe that L-idose is the best alternative to D-glucose in studies on aldose reductase.

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Human recombinant carbonyl reductase 1 (E.C. 1.1.1.184, hCBR1) is shown to efficiently act as aldehyde reductase on glutathionylated alkanals, namely 3-glutathionyl-4-hydroxynonanal (GSHNE), 3-glutathionyl-nonanal, 3-glutathionyl-hexanal and 3-glutathionyl-propanal. The presence of the glutathionyl moiety appears as a necessary requirement for the susceptibility of these compounds to the NADPH-dependent reduction by hCBR1. In fact the corresponding alkanals and alkenals, and the cysteinyl and γ-glutamyl-cysteinyl alkanals adducts were either ineffective or very poorly active as CBR1 substrates. Mass spectrometry analysis reveals the ability of hCBR1 to reduce GSHNE to the corresponding GS-dihydroxynonane (GSDHN) and at the same time to catalyze the oxidation of the hemiacetal form of GSHNE, generating the 3-glutathionylnonanoic-δ-lactone. These data are indicative of the ability of the enzyme to catalyze a disproportion reaction of the substrate through the redox recycle of the pyridine cofactor. A rationale for the observed preferential activity of hCBR1 on different GSHNE diastereoisomers is given by molecular modelling. These results evidence the potential of hCBR1 acting on GSHNE to accomplish a dual role, both in terms of HNE detoxification and, through the production of GSDHN, in terms of involvement into the signalling cascade of the cellular inflammatory response.