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To date, efficiency upon non-viral DNA delivery remains low and this implies the existence of unidentified transfection barriers. Here we explore the mechanisms of action of multicomponent (MC) cationic liposome/DNA complexes (lipoplexes) by a combination of reporter technologies, dynamic light scattering (DLS), synchrotron small angle X-ray scattering (SAXS), fluorescence activated cell sorting (FACS) analysis and laser scanning confocal microscopy (LSCM) in live cells. Lipofectamine - the gold standard among transfection reagents - was used as a reference. On the basis of our results, we suggest that an additional transfection barrier impairs transfection efficiency, that is: low lipoplex concentration at the cell surface. Based on the acquired knowledge we propose an optimized transfection protocol that allowed us to efficiently transfect DND41, JURKAT, MOLT3, P12-ICHIKAWA, ALL-SILL, TALL-1 human T-cell acute lymphoblastic leukemia (T-ALL) cell lines known to be difficult-to-transfect by using non-viral vectors and where LFN-based technologies fail to give satisfactory results.

In physiological environments (e.g. the blood), nanoparticles (NPs) are surrounded by a layer of biomolecules referred to as a ‘protein corona’ (PC). The most tightly NP-bound proteins form the so-called hard corona (HC), the key bio-entity that determines the NP's biological identity and physiological response. To date, NP-HC has been almost exclusively characterized in vitro, while NP–protein interactions under realistic in vivo conditions remain largely unexplored. In this study, we thoroughly characterized the in vivo HC of a NP formulation that forms around lipid nanoparticles with a lipid composition equal to that of clinically used liposomal amphotericin B (AmBisome®) after the recovery of the NPs from the blood circulation of FVB/N mice 10 minutes post intravenous administration. In vitro HC formed by 10 minutes incubation of NPs in FVB/N mouse plasma was used for comparison. Here we show that the biological identity (i.e. size, zeta-potential and aggregation state) of NPs in vivo is significantly different from that acquired in vitro. Furthermore, the variety of protein species in the in vivo HC was considerably larger. The present work has demonstrated that characterization of the in vivo HC is essential to provide an accurate molecular description of the biological identity of NPs in physiological environments.

HER2 tyrosine kinase receptor is a validated target in breast cancer therapy. However, increasing evidence points to a major role of Δ16HER2 splice variant commonly coexpressed with HER2 and identified as a clinically important HER2 molecular alteration promoting aggressive metastatic breast cancer. Consistently, mice transgenic for the human Δ16HER2 isoform (Δ16HER2 mice) develop invasive mammary carcinomas with early onset and 100% penetrance. The present study provides preclinical evidence that Δ16HER2 expression confers de novo resistance to standard anti-HER2-therapies such as Lapatinib and acquired resistance to the selective Src inhibitor Saracatinib in breast cancer. Of note, Dacomitinib, an irreversible small molecule pan-HER inhibitor, was able to completely suppress Δ16HER2-driven breast carcinogenesis. Thus, only Dacomitinib may offer benefit in this molecularly defined patient subset by irreversibly inhibiting Δ16HER2 activation.

Ruthenium compounds have become promising alternatives to platinum drugs by displaying specific activities against different cancers and favorable toxicity and clearance properties. Here, we show that the ruthenium(II) complex [Ru(p-cymene)(bis(3,5-dimethylpyrazol-1-yl)methane)Cl]Cl (UNICAM-1) exhibits potent in vivo antitumor effects. When administered as four-dose course, by repeating a single dose (52.4mgkg-1) every three days, UNICAM-1 significantly reduces the growth of A17 triple negative breast cancer cells transplanted into FVB syngeneic mice. Pharmacokinetic studies indicate that UNICAM-1 is rapidly eliminated from kidney, liver and bloodstream thanks to its high hydrosolubility, exerting excellent therapeutic activity with minimal side effects. Immunohistological analysis revealed that the efficacy of UNICAM-1, mainly relies on its capacity to reverse tumor-associated immune suppression by significantly reducing the number of tumor-infiltrating regulatory T cells. Therefore, UNICAM-1 appears very promising for the treatment of TNBC.