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Purpose: In a previous study, we demonstrated that the combination of fenretinide with lenalidomide, administered by a novel nanomicellar formulation (FLM), provided a strong antitumor effect in a neuroblastoma TrkB-expressing tumor. In this study, we tested the nanomicellar combination in an MYCN amplified neuroblastoma xenograft to assess its efficacy in different tumor genotypes and evaluate the interactions of the nanomicelles with the tumor cells. Experimental Design: FLM was administered to mice bearing human NLF xenografts to evaluate its efficacy in comparison with the nanomicelles containing fenretinide alone (FM). Confocal laser-scanning fluorescence microscopy images of the NLF cells treated with FLM and FM allowed us to estimate the nanomicelle ability to transport the encapsulated drugs inside the tumor cells. Flow cytometric analysis of the cells from treated tumors was performed to assess the effect of treatment on GD2 expression and NK cell infiltration. Results: FLM and FM decreased the growth of NLF xenografts at comparable extents during the treatment period. Afterwards, FLM induced a progressive tumor regression without regrowth, while FM treatment was followed by regrowth within 15-20 days after the end of treatment. Both FLM and FM were able to penetrate the tumor cells transporting the encapsulated drugs. FLM transported higher amount of fenretinide inside the cells. Also, FLM treatment strongly increased GD2 expression in treated tumors and slightly decreased the NK infiltration compared to FM. Conclusion: FLM treatment induced a superior antitumor response than FM in NLF xenografts, presumably due to the combined effects of fenretinide cytotoxicity and lenalidomide antiangiogenic activity. The ability of FLM to penetrate tumor cells, transporting the encapsulated drugs, substantially improved the therapeutic efficiency of this system. Moreover, the enhancement of GD2 expression in FLM treated tumors offers the possibility to further increase the antitumor effect by the use of anti-GD2 CAR-T cells and anti-GD2 antibodies in combination with FLM in multimodal therapies.

Chlorhexidine (CHX) is a bis-bis-guanide widely used to treat skin and mucosa infections, efficient against a wide range of microbial species. The aim of this work was to design and evaluate gels containing CHX associated to mucoadhesive and swelling agents, such as CMC, HPMC, HPC and Poloxamer, to control both the residence time in the oral cavity and the release rate of the drug. Three tests were carried out to evaluate the controlled release of CHX from the gels; also the interaction polymer-mucin by means of viscosimetric measurements was tested. The same tests were also applied to a commercial formulation, Corsodyl gel® for comparison.

Sodium ascorbate, at millimolar concentrations, induces apoptosis of neuroblastoma cell lines in vitro. The caspase cascade is activated following treatment with ascorbate, as assessed by fluorescence assay with the pan-caspase substrate z-VAD-fmk. Sodium ascorbate down-modulates CD71 (transferrin receptor) membrane expression, although overall (membrane and cytoplasmic) expression is not significantly affected. Since NB cells are strongly dependent on iron supply, it is likely that redistribution of CD71 within cellular compartments interferes with a correct iron metabolism, giving rise to apoptosis. The time- and dose-dependence, as well as the extent of the effects of sodium ascorbate on NB cells is likely to depend upon differences in its catabolism and the intensity of CD71 recycling and membrane re-expression among the different NB cell lines. Due to its lack of overt toxicity, high-dose sodium ascorbate can be considered as an additional drug in the traditional therapeutic schedules for NB.

Naphazoline (NPH) is a vasoconstrictor agent, and reduces inflammation and swelling of the conjunctiva. The effect of naphazoline arises from its direct binding to adrenergic receptor sites on unstriated muscle cells in the blood vessels. A modern tendency of ocular delivery is represented by systems capable of both lengthening pre-cornea1 contact time and slowing the release of drug from the vehicle. There is considerable logic in attempting the retention of the delivery systems in the front of the eye, because of the enormous loss of an instilled drug solution that typically occurs soon after administration. In this study we present a low viscous formulation with mucoadesive properties to control the residence time in pre-corneal area and the release and permeation rates of drug.

The anti-tumour activity of fatty acids has been extensively investigated upon a wide range of tumour cell lines. The fatty alcohols activity, on the contrary, has been scarcely studied. It has been reported that the alcohols are more active than the corresponding acids and that unsaturated fatty alcohols inhibits DNA synthesis and growth of Erlich ascites tumour cells more efficiently than their saturated analogs. The interest in oleyl alcohol arises from dietary effects of essential fatty acids and alcohols and their involvement in cardiovascular disorders and cancers. Moreover, oleyl alcohol (cis-9-octadecen-1-ol) was reported to be one of the most active among a series of saturated and unsaturated fatty alcohols and the presence of a single insaturation makes it more stable to oxidation than multiple unsaturations. Since activity is proportionally correlated to the fatty alcohol intracellular accumulation, which depends on the balance of their hydrophobic/ hydrophilic properties and, primarily, on their ability to be solubilized in aqueous media, in this work we evaluate the possibility to improve oleyl alcohol aqueous solubilization by complexation with non toxic amphiphilic polymers self-assembling in aqueous environment. The aim is to develop safe parenteral formulations holding oleyl alcohol solubilization levels suitable to elicit therapeutic responses. The amphiphilic polymers were prepared by partial substitution of polyvinyl alcohol with oleyl chains through a succinyl spacer, in the hypothesis, previously demonstrated in an almost similar situation concerning doxorubicin [1, 2], that structural similarities should improve mutual affinity between the solubilizer and the solubilizing agent.

Naphazoline (NPH) is a vasoconstrictor agent, and reduces inflammation and swelling of the conjunctiva. The effect of naphazoline arises from its direct binding to adrenergic receptor sites on unstriated muscle cells in the blood vessels. A modern tendency of ocular delivery is represented by systems capable of both lengthening pre-cornea1 contact time and slowing the release of drug from the vehicle. There is considerable logic in attempting the retention of the delivery systems in the front of the eye, because of the enormous loss of an instilled drug solution that typically occurs soon after administration. In this study we present a low viscous formulation with mucoadesive properties to control the residence time in pre-corneal area and the release and permeation rates of drug.

Poly-vinylalcohol (PVA), conjugated with oleoyl (PVA-OL) or linoleoyl (PVA-LINOL) chain forms polymer micelles able to solubilize retinoic acid (ATRA). The functional properties of the solubilized systems were evaluated by dynamic light scattering (DLS) and correlated to the physico-chemical characteristics of ATRA and polymer solution. The mean diameter of the aggregates and the counts per second are indicative of the total micelle volume (TMV), used to predict the complexing ability of the amphiphilic micelles towards the hydrophobic drug. TMV was found higher for PVA-LINOL than for PVA-OL and increased at increasing polymer concentration. Increase of temperature increased TMV of both polymers. The effect of filtration on the nature of the final systems was also discussed. Changes, after filtration, was attributed to fragmentation occurring, when aggregates of size, larger than the filter pores, are forced to pass through these pores: aging of the systems in some cases again drives up the formation of larger aggregates. Thermodynamic entities for retinoic acid solubilization into polymer micelles were calculated, assuming that the process is a partition between the bulk solution and the hydrophobic core of micelles.

Recently, several chemotherapeutic drugs have been repositioned in neurological diseases, based on common biological backgrounds and the inverse comorbidity between cancer and neurodegenerative diseases. Fenretinide (all-trans-N-(4-hydroxyphenyl) retinamide, 4-HPR) is a synthetic derivative of all-trans-retinoic acid initially proposed in anticancer therapy for its antitumor effects combined with limited toxicity. Subsequently, fenretinide has been proposed for other diseases, for which it was not intentionally designed for, due to its ability to influence different biological pathways, providing a broad spectrum of pharmacological effects. Here, we review the most relevant preclinical and clinical findings from fenretinide and discuss its therapeutic role towards cancer and neurological diseases, highlighting the hormetic behavior of this pleiotropic molecule.

This study investigated the antitumor effect of a new nanomicellar complex obtained by combining the antitumor agent fenretinide with a quaternary amphiphilic amine RC16+ also endowed with antitumor activity. Methods: The complex (Fen-RC16+) strongly improved the aqueous solubility of fenretinide (from 1,71 ± 0.08 µg/ml, pure fenretinide to 1500 ± 164 µg /ml, Fen-RC16+ complex) and provided a cytotoxic effect on SH-SY5Y neuroblastoma cell lines resulting from the intrinsic activity of both the complex components. Moreover, the mean size of the nanomicellar complex (ranging from 20 ± 1.97 nm to 40 ± 3.05 nm) was suitable for accumulation to the tumor site by the enhanced permeability and retention effect and the positive charge provided by the quaternary RC16+ induced adsorption of the complex on the tumor cell surface improving the intracellular concentration of fenretinide. Results: All these characteristics made the Fen-RC16+ complex a multitasking system for antitumor therapy. Conclusion: Indeed its in vivo activity, evaluated on SH-SY5Y xenografts, was strong, and the tumor growth did not resume after the treatment withdrawal.

Amyotrophic lateral sclerosis (ALS) is the most frequent motor neuron disease for which effective treatment options are still lacking. ALS occurs in sporadic and familial forms which are clinically indistinguishable; about 20% of familial ALS cases are linked to mutations of the superoxide dismutase 1 (SOD1) gene. Fenretinide (FEN), a cancer chemopreventive and antiproliferative agent currently used in several clinical trials, is a multi-target drug which also exhibits redox regulation activities. We analyzed the effects of FEN on mutant SOD1 (mSOD1) toxicity in motoneuronal (NSC34) and a muscle (C2C12) cell lines and evaluated the impacts of chronic administration of a new nanomicellar fenretinide formulation (NanoMFen) on ALS disease progression in the SOD1G93A mouse model. The results showed that FEN significantly prevents the toxicity of mSOD1 expression in NSC34 motor neuron; furthermore, FEN is able to partially overcome the toxic effect of mSOD1 on the myogenic program of C2C12 muscle cells. Administration of NanoMFen ameliorates the disease progression and increases median survival of mSOD1G93A ALS mice, even when given after disease onset; beneficial effects in ALS mice, however, is restricted to female sex. Our data support the therapeutic potential of FEN against ALS-associated SOD1G93A mutant protein toxicity and promote further studies to elucidate specific cellular targets of the drug in ALS. Furthermore, the sex-related efficacy of NanoMFen in mSOD1G93A ALS mice strengthens the importance, in the perspective of a precision medicine approach, of gender pharmacology in ALS research.

At present, there is no vaccine or effective standard treatment for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection (or coronavirus disease-19 (COVID-19)), which frequently leads to lethal pulmonary inflammatory responses. COVID-19 pathology is characterized by extreme inflammation and amplified immune response with activation of a cytokine storm. A subsequent progression to acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) can take place, which is often followed by death. The causes of these strong inflammatory responses in SARS-CoV-2 infection are still unknown. As uncontrolled pulmonary inflammation is likely the main cause of death in SARS-CoV-2 infection, anti-inflammatory therapeutic interventions are particularly important. Fenretinide N-(4-hydroxyphenyl) retinamide is a bioactive molecule characterized by poly-pharmacological properties and a low toxicity profile. Fenretinide is endowed with antitumor, anti-inflammatory, antiviral, and immunomodulating properties other than efficacy in obesity/diabetic pathologies. Its anti-inflammatory and antiviral activities, in particular, could likely have utility in multimodal therapies for the treatment of ALI/ARDS in COVID-19 patients. Moreover, fenretinide administration by pulmonary delivery systems could further increase its therapeutic value by carrying high drug concentrations to the lungs and triggering a rapid onset of activity. This is particularly important in SARS-CoV-2 infection, where only a narrow time window exists for therapeutic intervention.

Fenretinide is a synthetic retinoid characterized by anticancer activity in preclinical models and favorable toxicological profile, but also by a low bioavailability that hindered its clinical efficacy in former clinical trials. We developed a new formulation of fenretinide complexed with 2-hydroxypropyl-beta-cyclodextrin (nanofenretinide) characterized by an increased bioavailability and therapeutic efficacy. Nanofenretinide was active in cell lines derived from multiple solid tumors, in primary spheroid cultures and in xenografts of lung and colorectal cancer, where it inhibited tumor growth independently from the mutational status of tumor cells. A global profiling of pathways activated by nanofenretinide was performed by reverse-phase proteomic arrays and lipid analysis, revealing widespread repression of the mTOR pathway, activation of apoptotic, autophagic and DNA damage signals and massive production of dihydroceramide, a bioactive lipid with pleiotropic effects on several biological processes. In cells that survived nanofenretinide treatment there was a decrease of factors involved in cell cycle progression and an increase in the levels of p16 and phosphorylated p38 MAPK with consequent block in G0 and early G1. The capacity of nanofenretinide to induce cancer cell death and quiescence, together with its elevated bioavailability and broad antitumor activity indicate its potential use in cancer treatment and chemoprevention.

Background An increasing number of anticancer agents has been proposed in recent years with the attempt to overcome treatment-resistant cancer cells and particularly cancer stem cells (CSC), the major culprits for tumour resistance and recurrence. However, a huge obstacle to treatment success is the ineffective delivery of drugs within the tumour environment due to limited solubility, short circulation time or inconsistent stability of compounds that, together with concomitant dose-limiting systemic toxicity, contribute to hamper the achievement of therapeutic drug concentrations. The synthetic retinoid Fenretinide (4-hydroxy (phenyl)retinamide; 4-HPR) formerly emerged as a promising anticancer agent based on pre-clinical and clinical studies. However, a major limitation of fenretinide is traditionally represented by its poor aqueous solubility/bioavailability due to its hydrophobic nature, that undermined the clinical success of previous clinical trials. Methods Here, we developed a novel nano-micellar fenretinide formulation called bionanofenretinide (Bio-nFeR), based on drug encapsulation in an ion-pair stabilized lipid matrix, with the aim to raise fenretinide bioavailability and antitumour efficacy. Results Bio-nFeR displayed marked antitumour activity against lung, colon and melanoma CSC both in vitro and in tumour xenografts, in absence of mice toxicity. Bio-nFeR is suitable for oral administration, reaching therapeutic concentrations within tumours and an unprecedented therapeutic activity in vivo as single agent. Conclusion Altogether, our results indicate Bio-nFeR as a novel anticancer agent with low toxicity and high activity against tumourigenic cells, potentially useful for the treatment of solid tumours of multiple origin. Electronic supplementary material The online version of this article (10.1186/s13046-019-1383-9) contains supplementary material, which is available to authorized users.

Novel polylactide (PLA) microspheres endowed with hydrophilic and bioadhesive surfaces as injectable formulations for the controlled release of fenretinide were prepared, using a novel technique based on the co-precipitation of PLA with gelatin, at the interface of a liquid dispersion formed by the addition of N-methylpyrrolidone containing PLA and dextrin (DX), towards an aqueous solution of gelatin (G). The resulting PLA-G-DX microspheres were compared with others prepared by the same technique using polylactide-co-glycolide (PLGA), with or without DX, and with or without phosphatidylcholine. Of the different systems, the PLA-G-DX microspheres had the best morphological, dimensional and functional characteristics. They had the highest drug loading, and their drug release was the most efficient over time without any burst effect. Their in vitro anti-tumoural activity was strongly enhanced with respect to the pure fenretinide. This paralleled the increased drug concentration inside the cells due to their marked bioadhesion to the tumour cell membranes as indicated by scanning electron microscope images.

Objectives The major limitation to successful chemotherapy of neuroblastoma (NB) is the toxicity and the poor bioavailability of traditional drugs. Methods We synthesised an amphiphilic dextrin derivative (DX-OL) able to host fenretinide (4-HPR) by complexation. In this study, we have investigated the effects of 4-HPR-loaded amphipilic dextrin (DX-OL/4-HPR) in comparison with 4-HPR alone both in vitro on human NB cells and in vivo in pseudometastatic NB models. The haemolysis assay was used as a measure of the potential damage caused by the pharmaceutical formulation in vivo. Pharmacokinetic experiments were performed to assess drug plasma levels in mice treated with free or complexed 4-HPR. Key findings DX-OL/4-HPR exerted a more potent cytotoxic activity on NB cells. Complexed 4-HPR significantly increased the proportion of sub-G1 cells with respect to free 4-HPR. Dextrin derivatives showed no haemolytic activity, indicating their suitability for parenteral administration. DX-OL/4-HPR increased the lifespan and the long-term survival of treated mice over controls. The analysis of drug plasma levels indicates that the complexed drug has a higher AUC due to a reduced clearance from the blood. Conclusions Our data suggest that DX-OL/4-HPR is an injectable formulation that is able to improve drug aqueous solubility and bioavailability.

This study relates to the preparation of a series of amphiphilic dextrins and their evaluation as complexing agents for anti-tumor hydrophobic drugs such as fenretinide, paclitaxel, etoposide, and camptothecin. The amphiphilic dextrins were obtained by conjugation of low molecular weight dextrin (average molecular weight 1670, average polymerization degree 9.33 glucose monomer) with hydrocarbon chains at substitution degree of about 0.1 mole hydrocarbon chain per mole of glucose monomer, as confirmed by 1H-NMR spectra. The conjugates were highly soluble in water and dissolved with formation of nano-aggregates endowed with hydrophobic inner cores able to host hydrophobic drugs by complexation. Complexation raised hydrophobic drugs aqueous solubility; the best results were obtained with fenretinide. Solid complexes with fenretinide were prepared by using three different approaches: the kneading method, the co-solubilisation method, and the co-precipitation method. Kneading method provided the complexes endowed with the best functional properties. Thermogravimetric analysis on solid samples suggested a notable thermal stability up to 300 degrees C for both the conjugated dextrins and the solid complexes. In differential scanning calorimetry profiles no significant differences were observed among amphiphilic dextrins and complexed drug, indicating that the guest molecule exists in an amorphous state in the solid matrices. Particle size analysis confirmed the dimensional suitability of the complexes for parenteral administration. Moreover, sustained drug release, in vitro, has been observed from all the complexes analyzed. Regarding the biological effects, the cytotoxicity of complexed fenretinide towards HTLA-230 neuroblastoma cell line was always higher than the free drug, suggesting that complexation increased drug bioavailability. These findings, taken together, indicated that these biodegradable, self-assembling dextrin conjugates may be regarded as new potential complexing agents for hydrophobic drugs and, in particular, for fenretinide, to increase drug solubility, bioavailability, and thus therapeutic efficacy.

The present study deals with the preparation of albumin nanocapsules containing fenretinide and their evaluation in experimental models of human non-small cell lung cancer. These nanocapsules showed enhanced antitumor activity with respect to free fenretinide due to the solubilization effect of albumin on the hydrophobic drug, known to improve bioavailability. The high expression of caveolin-1 on the A549 cell surface further enhanced the antitumor activity of the nanoencapsulated fenretinide. Caveolin-1 favored albumin uptake and improved the efficacy of the fenretinide-loaded albumin nanocapsules, especially in 3-D cultures where the densely packed 3-D structures impaired drug diffusibility and severely reduced the activity of the free drug. The efficacy of the fenretinide albumin nanocapsules was further confirmed in tumor xenograft models of A549 by the significant delay in tumor progression observed with respect to control after intravenous administration of the novel formulation. From the Clinical Editor This study describes the preparation of fenretinide containing albumin nanocapsules and their evaluation in experimental models of non-small cell lung cancer, showing enhanced antitumor activity compared to free fenretinide.

Background and purpose 13-cis-Retinoic acid represents a well-established clinical strategy for the management of minimal residual disease of high risk neuroblastoma (NB) patients. However, the clinical efficacy on the overall survival of these patients remains limited, addressing the issue of better understanding the molecular mechanisms and intracellular pathways mediating Retinoic Acid (RA) clinical effects. Experimental approach This work investigates the mechanism underlying the sensitivity/resistance to RA in NB by taking advantage of the paired SK-N-AS/rAS-ST cells showing different responsivity to ATRA. The subline rAS-ST was selected by inducing resistance to the novel retinoid ST1926 in the NB SK-N-AS cell line. Key results Resistance to ST1926 was neither dependent on cellular uptake nor on multi-drug resistance phenotype. Rather, both delayed/lower DNA damage and apoptosis appeared involved in reduced sensitivity of rAS-ST cells to ST1926. This subline showed enhanced responsivity to ATRA compared to the wt counterpart, that was associated with enhanced RARα/β expression, DNA damage, G2 accumulation, PI3K/AKT pathway inhibition, cellular differentiation and delayed telomerase inhibition, without involvement of either p27/p53 or caspase-mediated apoptosis. Conclusions and implications The present data add important information to the understanding of RA sensitivity in NB, providing further insights towards a more efficacious clinical use of this drug.