Federica Foglietta

Application of lipid nanoparticles to ocular drug delivery

ABSTRACT Introduction: Although eye drops are widely used as drug delivery systems for the anterior segment of the eye, they are also associated with poor drug bioavailability due to transient contact time and rapid washout by tearing. Moreover, effective drug delivery to the posterior segment of the eye is challenging, and alternative routes of administration (periocular and intravitreal) are generally needed, the blood–retinal barrier being the major obstacle to systemic drug delivery. Areas covered: Nanotechnology, and especially lipid nanoparticles, can improve the therapeutic efficiency, compliance and safety of ocular drugs, administered via different routes, to both the anterior and posterior segment of the eye. This review highlights the main ocular barriers to drug delivery, as well as the most common eye diseases suitable for pharmacological treatment in which lipid nanoparticles have proved efficacious as alternative delivery systems. Expert opinion: Lipid-based nanocarriers are among the most biocompatible and versatile means for ocular delivery. Mucoadhesion with consequent increase in pre-corneal retention time, and enhanced permeation due to cellular uptake by corneal epithelial cells, are the essential goals for topical lipid nanoparticle delivery. Gene delivery to the retina has shown very promising results after intravitreal administration of lipid nanoparticles as non-viral vectors.

Nanosonotechnology: the next challenge in cancer sonodynamic therapy

Abstract Sonodynamic therapy (SDT) is a newly developed anticancer treatment where ultrasound is used to trigger the cytotoxic effect of chemical compounds, known as sonosensitizers. Although SDT is similar to photodynamic therapy (PDT), SDT activates the chemical compounds through energy transfer using ultrasound rather than light. Moreover, SDT can focus the ultrasound energy onto malignant sites situa\xadted deeply within tissues, thus overcoming the main drawback linked to the use of PDT. Several physical and chemical mechanisms underlying ultrasound bioeffects and anticancer SDT take advantage of the non-thermal effect of acoustic cavitation generated by selected pulsed or continuous ultrasound. As the physical-chemical structure of the sonosentizer is essential for the success of SDT, we believe that the different aspects related to nanotechnology in medicine might well be able to improve the triggering effect ultrasound has on sonosensitizing agents. Therefore, the aim of this review is to focus on how nanotechnology might improve this innovative anticancer therapeutic approach.

Polymeric nanoparticles enhance the sonodynamic activity of meso-tetrakis (4-sulfonatophenyl) porphyrin in an in vitro neuroblastoma model

Purpose Sonodynamic therapy is a developing noninvasive modality for cancer treatment, based on the selective activation of a sonosensitizer agent by acoustic cavitation. The activated sonosensitizer agent might generate reactive oxygen species leading to cancer cell death. We investigated the potential poly-methyl methacrylate core-shell nanoparticles (NPs) loaded with meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS) have to function as an innovative sonosensitizing system, ie, TPPS-NPs. Methods Shockwaves (SWs) generated by a piezoelectric device were used to induce acoustic cavitation. The cytotoxic effect of the sonodynamic treatment with TPPS-NPs and SWs was investigated on the human neuroblastoma cell line, SH-SY5Y. Cells were exposed for 12 hours to TPPS-NPs (100 μg/mL) and then to SWs (0.43 mJ/mm2 for 500 impulses, 4 impulses/second). Treatment with SWs, TPPS, and NPs alone or in combination was carried out as control. Results There was a statistically significant decrease in SH-SY5Y cell proliferation after the sonodynamic treatment with TPPS-NPs and SWs. Indeed, there was a significant increase in necrotic (16.91% ± 3.89%) and apoptotic (27.45% ± 3.03%) cells at 48 hours. Moreover, a 15-fold increase in reactive oxygen species production for cells exposed to TPPS-NPs and SWs was observed at 1 hour compared with untreated cells. A statistically significant enhanced mRNA (messenger ribonucleic acid) expression of NRF2 (P<0.001) and a significant downregulation of TIGAR (P<0.05) and MAP3K5 (P<0.05) genes was observed in cells exposed to TPPS-NPs and SWs at 24 hours, along with a statistically significant release of cytochrome c (P<0.01) at 48 hours. Lastly, the sonosensitizing system was also investigated in an in vitro three-dimensional model, and the sonodynamic treatment significantly decreased the neuroblastoma spheroid growth. Conclusion The sonosensitizing properties of TPPS were significantly enhanced once loaded onto NPs, thus enhancing the sonodynamic treatment’s efficacy in an in vitro neuroblastoma model.

Engineered porphyrin loaded core-shell nanoparticles for selective sonodynamic anticancer treatment

AIM Porphyrin-loaded core-shell nanoparticles have been engineered for use as in vivo sonosensitizing systems, radio-tracers or magnetic resonance (MR) imaging agents, which may be suitable for the selective treatment of solid tumors and imaging analyses. MATERIALS & METHODS Polymethyl methacrylate nanoparticles (PMMANPs) have been either loaded with meso-tetrakis (4-sulphonatophenyl) porphyrin (TPPS) for sonodynamic anticancer treatment, with (64)Cu-TPPS for positron emission tomography biodistribution studies or with Mn(III)-TPPS for MR tumor accumulation evaluation. RESULTS PMMANPs are easily functionalized with negatively charged molecules and show favorable biodistribution. In vivo TPPS-PMMANPs have demonstrated shock wave responsiveness in a Mat B III syngeneic rat breast cancer model as measured by MR analyses of pre- and post-treatment tumor volumes. CONCLUSION TPPS-PMMANPs are a multimodal system which can efficiently induce in vivo sonodynamic anticancer activity.

Squaraines bearing halogenated moieties as anticancer photosensitizers: Synthesis, characterization and biological evaluation

We report the synthesis and characterization of a series of symmetrical indolenine-based squaraine dyes along with the evaluation of their singlet oxygen generation efficiency. The photodynamic activity of these new photosensitizers has been evaluated on a human tumor fibrosarcoma (HT-1080) cell line. The cytotoxicity increased over time and is induced by the photoactivation of bromo (Br-C4) and iodio (I-C4) long carbon chain squaraine dyes and the consequent increase in reactive oxygen species (ROS) production (p < 0.001), which leads to necrosis 6 h after treatment. Induction of cytochrome c release, DNA damage and up-regulation of GPX1, NQO1 and SOD2 mRNA gene expression after PDT were investigated.

Modulation of Butyrate Anticancer Activity by Solid Lipid Nanoparticle Delivery: An in Vitro Investigation on Human Breast Cancer and Leukemia Cell Lines

PURPOSE Histone modification has emerged as a promising approach to cancer therapy. The short-chain fatty acid, butyric acid, a histone deacetylase (HD) inhibitor, has shown anticancer activity. Butyrate transcriptional activation is indeed able to withdraw cancer cells from the cell cycle, leading to programmed cell death. Since butyrates clinical use is hampered by unfavorable pharmacokinetic and pharmacodynamic properties, delivery systems, such as solid lipid nanoparticles (SLN), have been developed to overcome these constraints. METHODS In order to outline the influence of butyrate delivery on its anticancer activity, the effects of butyrate as a free (sodium butyrate, NB) or nanoparticle (cholesteryl butyrate solid lipid nanoparticles, CBSLN) formulation on the growth of different human cancer cell lines, such as the promyelocytic leukemia, HL-60, and the breast cancer, MCF-7 was investigated. A detailed investigation into the mechanism of the induced cytotoxicity was also carried out, with a special focus on the modulation of HD and cyclin-dependent kinase (CDK) mRNA gene expression by real time PCR analysis. RESULTS In HL-60 cells, CBSLN induced a higher and prolonged expression level of the butyrate target genes at lower concentrations than NB. This led to a significant decrease in cell proliferation, along with considerable apoptosis, cell cycle block in the G0/G1 phase, significant inhibition of total HD activity and overexpression of the p21 protein. Conversely, in MCF-7 cells, CBSLN did not enhance the level of expression of the butyrate target genes, leading to the same anticancer activity as that of NB. CONCLUSIONS Solid lipid nanoparticles were able to improve butyrate anticancer activity in HL-60, but not in MCF-7 cells. This is consistent with difference in properties of the cells under study, such as expression of the TP53 tumor suppressor, or the transporter for short-chain fatty acids, SLC5A8.

Photodynamic activity of thiophene-derived lysosome-specific dyes.

The photodynamic activity occurring through the lysosome photo-damage is effective in terms of triggered synergic effects which can avoid chemo-resistance pathways. The potential photodynamic activity of two fluorescent lysosome-specific probes was studied providing their interaction with human serum albumin, demonstrating their in vitro generation of singlet oxygen and investigating the resulted photo-toxic effect in human cancer cells.

Solid Lipid Nanoparticles Loaded with Fluorescent-labelled Cyclosporine A: Anti-Inflammatory Activity In Vitro

FMOC-isocyclosporine A, a fluorescent labeled cyclosporine A, was encapsulated in solid lipid nanoparticles (SLN) prepared by the coacervation technique, and its anti-inflammatory activity was evaluated. The anti-inflammatory activity of the fluorescent labelled molecule, measured as inhibition of TNF-α secretion, is similar to the native one. SLN were compared to commercial formulations, through measurement of cytokine release and drug uptake in rat peripheral blood mononuclear cells. Drug-loaded SLN inhibit TNF-α secretion in a lower extent than commercial formulations, probably due to a lower uptake by the cells, but the increase of IL-10 secretion caused by the lipid matrix itself makes this formulation interesting for its anti-inflammatory activity.

Insight into ultrasound-mediated reactive oxygen species generation by various metal-porphyrin complexes

ABSTRACT Ultrasound is used to trigger the cytotoxicity of chemical compounds, known as sonosensitisers, in an approach called sonodynamic therapy (SDT), which is under investigation herein. The generation of reactive oxygen species (ROS) has been proposed as the main biological occurrence that leads to the cytotoxic effects, which are achieved via the synergistic action of two components: the energy‐absorbing sonosensitiser and ultrasound (US), which are both harmless per se. Despite some promising results, a lack of investigation into the mechanisms behind US sonosensitiser‐mediated ROS generation has prevented SDT from reaching its full potential. The aim of this work is to investigate the US‐responsiveness of a variety of metal‐porphyrin complexes, free‐base porphyrin and Fe(III), Zn(II) and Pd(II) porphyrin, by analyzing their ROS generation under US exposure and related bio‐effects. All experiments were also carried out under light exposure and the results were used as references. Our results show that porphyrin ultrasound‐responsiveness depends on the metal ion present, with Zn(II) and Pd(II) porphyrin being the most efficient in generating singlet oxygen and hydroxyl radicals. ROS production efficiency is lower after ultrasound exposure than after light exposure, because of the various physico‐chemical mechanisms involved in sensitiser activation. US and porphyrin‐mediated ROS generation is oxygen‐dependent and the activation of porphyrin by US appears to be more compatible with sonoluminescence‐based photo‐activation rather than a radical path process that occurs via the homolytic bond rupture of water. Notably, the cytotoxicity results reported herein, which are mirrored by ex‐cellulo data, confirm that the type of ROS generation achieved by the US activation of intracellular porphyrins is pivotal to the effectiveness of cancer cell killing. HIGHLIGHTSThe ultrasound‐responsiveness of porphyrins depends on the metal moiety.Zn(II) and Pd(II) porphyrin complexes are the most efficient at generating ROS.US and porphyrin‐mediated ROS generation is oxygen‐dependent.The sonoluminescence role in the electronic excitation of porphyrins is suggested.The ultrasound activation of intracellular porphyrins leads to cancer cell death.

Solid lipid nanoparticles delivering anti-inflammatory drugs to treat inflammatory bowel disease: Effects in an in vivo model

AIM To improve anti-inflammatory activity while reducing drug doses, we developed a nanoformulation carrying dexamethasone and butyrate. METHODS Dexamethasone cholesteryl butyrate-solid lipid nanoparticles (DxCb-SLN) were obtained with the warm microemulsion method. The anti-inflammatory activity of this novel nanoformulation has been investigated in vitro (cell adhesion to human vascular endothelial cells and pro-inflammatory cytokine release by lipopolysaccharide-induced polymorphonuclear cells) and in vivo (disease activity index and cytokine plasma concentrations in a dextran sulfate sodium-induced mouse colitis) models. Each drug was also administered separately to compare its effects with those induced by their co-administration in SLN at the same concentrations. RESULTS DxCb-SLN at the lowest concentration tested (Dx 2.5 nmol/L and Cb 0.1 μmol/L) were able to exert a more than additive effect compared to the sum of the individual effects of each drug, inducing a significant in vitro inhibition of cell adhesion and a significant decrease of pro-inflammatory cytokine (IL-1β and TNF-α) in both in vitro and in vivo models. Notably, only the DxCb nanoformulation administration was able to achieve a significant cytokine decrease compared to the cytokine plasma concentration of the untreated mice with dextran sulfate sodium-induced colitis. Specifically, DxCb-SLN induced a IL-1β plasma concentration of 61.77% ± 3.19%, whereas Dx or Cb used separately induced a concentration of 90.0% ± 2.8% and 91.40% ± 7.5%, respectively; DxCb-SLN induced a TNF-α plasma concentration of 30.8% ± 8.9%, whereas Dx or Cb used separately induced ones of 99.5% ± 4.9% and 71.1% ± 10.9%, respectively. CONCLUSION Our results indicate that the co-administration of dexamethasone and butyrate by nanoparticles may be beneficial for inflammatory bowel disease treatment.