Valentina Gambini

Personalized liposome-protein corona in the blood of breast, gastric and pancreatic cancer patients

When nanoparticles (NPs) are dispersed in a biofluid, they are covered by a protein corona the composition of which strongly depends on the protein source. Recent studies demonstrated that the type of disease has a crucial role in the protein composition of the NP corona with relevant implications on personalized medicine. Proteomic variations frequently occur in cancer with the consequence that the bio-identity of NPs in the blood of cancer patients may differ from that acquired after administration to healthy volunteers. In this study we investigated the correlation between alterations of plasma proteins in breast, gastric and pancreatic cancer and the biological identity of clinically approved AmBisome-like liposomes as determined by a combination of dynamic light scattering, zeta potential analysis, one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (1D-SDS-PAGE) and semi-quantitative densitometry. While size of liposome-protein complexes was not significantly different between cancer groups, the hard corona from pancreatic cancer patients was significantly less negatively charged. Of note, the hard corona from pancreatic cancer patients was more enriched than those of other cancer types this enrichment being most likely due to IgA and IgG with possible correlations with the autoantibodies productions in cancer. Given the strict relationship between tumor antigen-specific autoantibodies and early cancer detection, our results could be the basis for the development of novel nanoparticle-corona-based screening tests of cancer.

Sanguinarine suppresses basal-like breast cancer growth through dihydrofolate reductase inhibition

Basal-like breast cancer (BLBC) remains a great challenge because of its clinically aggressive nature and lack of effective targeted therapy. We analyzed the potential anti-neoplastic effects of sanguinarine, a natural benzophenanthridine alkaloid, against BLBC cells. Sanguinarine treatment resulted in a reduction of cell migration, in a dose-dependent inhibition of cell viability and in the induction of cell death by apoptosis in both human (MDA-MB-231 cells) and mouse (A17 cells) in vitro models of BLBC. In vivo experiments demonstrated that oral administration of sanguinarine reduced the development and growth of A17 transplantable tumors in FVB syngeneic mice. Western blotting analysis revealed that suppression of BLBC growth by sanguinarine was correlated with a concurrent upregulation of p27 and downregulation of cyclin D1 and with the inhibition of STAT3 activation. In addition, we identified sanguinarine as a potent inhibitor of dihydrofolate reductase (DHFR), able to impair enzyme activity even in methotrexate resistant MDA-MB-231 cells. These results provide evidence that sanguinarine is a promising anticancer drug for the treatment of BLBC.

The water soluble ruthenium(II) organometallic compound [Ru(p-cymene)(bis(3,5 dimethylpyrazol-1-yl)methane)Cl]Cl suppresses triple negative breast cancer growth by inhibiting tumor infiltration of regulatory T cells.

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.

Manipulation of lipoplex concentration at the cell surface boosts transfection efficiency in hard-to-transfect cells

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 vivo protein corona patterns of lipid nanoparticles

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 NPs 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.

Lyotropic Liquid Crystalline Nanosystems as Drug Delivery Agents for 5-Fluorouracil: Structure and Cytotoxicity

Lyotropic cubic liquid-crystalline systems have received increasing attention due to their unique microstructural and physicochemical properties as efficient nanocarriers for drug delivery. We report the preparation and characterization of bulk phases and cubosome dispersions of phytantriol loaded with the anticancer drug 5-fluorouracil, in neutral and anionic forms. In both cases, a Pn3m cubic phase was observed. The phytantriol phase behavior can be influenced by the addition of ionic agents, and, to this purpose, a positively charged lipid, such as N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride salt (DOTAP), was included in the studied formulations. It was found to induce a variation of the spontaneous membrane curvature of the phytantriol lipid bilayer, generating a transition from the Pn3m to the Im3m cubic phase. When 5-fluorouracil, in its anionic form (5-FUs), was encapsulated in these latter systems, a further transition to the HII hexagonal phase was observed as a consequence of the formation of a complex phytantriol/DOTAP/5-FUs. The physicochemical characterization was performed with various complementary techniques including synchrotron small-angle X-ray scattering, dynamic light scattering, and attenuated total reflection Fourier transform infrared and UV resonance Raman spectroscopies. Encapsulation of 5-fluorouracil in the corresponding nanodispersions was evaluated, and their in vitro cytotoxicity was assessed in MDA-MB-231 cell line. Phytantriol cubosomes containing 5-fluorouracil showed a higher toxicity compared with the bare drug solution, and hence they represent potential nanocarriers in the delivery of 5-fluorouracil for cancer therapy.

Irreversible inhibition of Δ16HER2 is necessary to suppress Δ16HER2-positive breast carcinomas resistant to Lapatinib

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.