Nathalie Wauthoz

Lycorine, the main phenanthridine Amaryllidaceae alkaloid, exhibits significant antitumor activity in cancer cells that display resistance to proapoptotic stimuli: an investigation of structure-activity relationship and mechanistic insight.

Twenty-two lycorine-related compounds were investigated for in vitro antitumor activity using four cancer cell lines displaying different levels of resistance to proapoptotic stimuli and two cancer cell lines sensitive to proapoptotic stimuli. Lycorine and six of its congeners exhibited potency in the single-digit micromolar range, while no compound appeared more active than lycorine. Lycorine also displayed the highest potential (in vitro) therapeutic ratio, being at least 15 times more active against cancer than normal cells. Our studies also showed that lycorine exerts its in vitro antitumor activity through cytostatic rather than cytotoxic effects. Furthermore, lycorine provided significant therapeutic benefit in mice bearing brain grafts of the B16F10 melanoma model at nontoxic doses. Thus, the results of the current study make lycorine an excellent lead for the generation of compounds able to combat cancers, which are naturally resistant to proapoptotic stimuli, such as glioblastoma, melanoma, non-small-cell-lung cancers, and metastatic cancers, among others.

Lactose characteristics and the generation of the aerosol

The delivery efficiency of dry-powder products for inhalation is dependent upon the drug formulation, the inhaler device, and the inhalation technique. Dry powder formulations are generally produced by mixing the micronised drug particles with larger carrier particles. These carrier particles are commonly lactose. The aerosol performance of a powder is highly dependent on the lactose characteristics, such as particle size distribution and shape and surface properties. Because lactose is the main component in these formulations, its selection is a crucial determinant of drug deposition into the lung, as interparticle forces may be affected by the carrier-particle properties. Therefore, the purpose of this article is to review the various grades of lactose, their production, and the methods of their characterisation. The origin of their adhesive and cohesive forces and their influence on aerosol generation are described, and the impact of the physicochemical properties of lactose on carrier-drug dispersion is discussed in detail.

Formulations for Intranasal Delivery of Pharmacological Agents to Combat Brain Disease: A New Opportunity to Tackle GBM?

Despite recent advances in tumor imaging and chemoradiotherapy, the median overall survival of patients diagnosed with glioblastoma multiforme does not exceed 15 months. Infiltration of glioma cells into the brain parenchyma, and the blood-brain barrier are important hurdles to further increase the efficacy of classic therapeutic tools. Local administration methods of therapeutic agents, such as convection enhanced delivery and intracerebral injections, are often associated with adverse events. The intranasal pathway has been proposed as a non-invasive alternative route to deliver therapeutics to the brain. This route will bypass the blood-brain barrier and limit systemic side effects. Upon presentation at the nasal cavity, pharmacological agents reach the brain via the olfactory and trigeminal nerves. Recently, formulations have been developed to further enhance this nose-to-brain transport, mainly with the use of nanoparticles. In this review, the focus will be on formulations of pharmacological agents, which increase the nasal permeation of hydrophilic agents to the brain, improve delivery at a constant and slow release rate, protect therapeutics from degradation along the pathway, increase mucoadhesion, and facilitate overall nasal transport. A mounting body of evidence is accumulating that the underexplored intranasal delivery route might represent a major breakthrough to combat glioblastoma.

Solid dispersions of itraconazole for inhalation with enhanced dissolution, solubility and dispersion properties

The purpose of this study was to produce a dry powder for inhalation (DPI) of a poorly soluble active ingredient (itraconazole: ITZ) that would present an improved dissolution rate and enhanced solubility with good aerosolization properties. Solid dispersions of amorphous ITZ, mannitol and, when applicable, D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) were produced by spray-drying hydro-alcoholic solutions in which all agents were dissolved. These dry formulations were characterized in terms of their aerosol performances and their dissolution, solubility and physical properties. Modulate differential scanning calorimetry and X-ray powder diffraction analyses showed that ITZ recovered from the different spray-dried solutions was in an amorphous state and that mannitol was crystalline. The inlet drying temperature and, indirectly, the outlet temperature selected during the spray-drying were critical parameters. The outlet temperature should be below the ITZ glass transition temperature to avoid severe particle agglomeration. The formation of a solid dispersion between amorphous ITZ and mannitol allowed the dry powder to be produced with an improved dissolution rate, greater saturation solubility than bulk ITZ and good aerosol properties. The use of a polymeric surfactant (such as TPGS) was beneficial in terms of dissolution rate acceleration and solubility enhancement, but it also reduced aerosol performance. For example, significant dissolution rate acceleration (f(2)<50) and greater saturation solubility were obtained when introducing 1% (w/w) TPGS (mean dissolution time dropped from 50.4 min to 36.9 min and saturation solubility increased from 20 ± 3 ng/ml to 46 ± 2 ng/ml). However, the fine particle fraction dropped from 47 ± 2% to 37.2 ± 0.4%. This study showed that mannitol solid dispersions may provide an effective formulation type for producing DPIs of poorly soluble active ingredients, as exemplified by ITZ.

In vivo assessment of temozolomide local delivery for lung cancer inhalation therapy

The aim of this study was to compare the efficacy of local drug delivery by inhalation to intravenous delivery in a B16F10 melanoma metastatic lung model. Temozolomide was formulated as a suspension, which was elaborated and evaluated in terms of particle size, shape and agglomeration. An endotracheal administration device was used to aerosolise the suspension. This mode of delivery was evaluated at different temozolomide concentrations and was optimized for the uniformity of delivered dose, the droplet size distribution and the distribution of droplets in vivo. Of the particles in the stabilised suspension, 79% were compatible with the human respirable size range, and this formulation retained 100% in vitro anticancer activity as compared to temozolomide alone in three distinct cancer cell lines. The pulmonary delivery device provided good reproducibility in terms of both the dose delivered and the droplet size distribution. Most of the lung tissues that were exposed to aerosol droplets contained the particles, as revealed by fluorescent microscopy techniques. The global in vivo antitumour activity of the inhaled temozolomide provided a median survival period similar to that for intravenous temozolomide delivery, and three out of 27 mice (11%) survived with almost complete eradication of the lung tumours. The present study thus shows that inhalation of a simple liquid formulation is well tolerated and active against a very biologically aggressive mouse melanoma pulmonary pseudo-metastatic model. This inhalation delivery could be used to deliver other types of anticancer drugs.

Simple di- and trivanillates exhibit cytostatic properties toward cancer cells resistant to pro-apoptotic stimuli

A series of 33 novel divanillates and trivanillates were synthesized and found to possess promising cytostatic rather than cytotoxic properties. Several compounds under study decreased by >50% the activity of Aurora A, B, and C, and WEE1 kinase activity at concentrations <10% of their IC(50) growth inhibitory ones, accounting, at least partly, for their cytostatic effects in cancer cells and to a lesser extent in normal cells. Compounds 6b and 13c represent interesting starting points for the development of cytostatic agents to combat cancers, which are naturally resistant to pro-apoptotic stimuli, including metastatic malignancies.

New inhalation-optimized itraconazole nanoparticle-based dry powders for the treatment of invasive pulmonary aspergillosis

Purpose Itraconazole (ITZ) dry powders for inhalation (DPI) composed of nanoparticles (NP) embedded in carrier microparticles were prepared and characterized. Methods DPIs were initially produced by reducing the ITZ particle size to the nanometer range using high-pressure homogenization with tocopherol polyethylene 1000 succinate (TPGS, 10% w/w ITZ) as a stabilizer. The optimized nanosuspension and the initial microsuspension were then spray-dried with different proportions of or in the absence of mannitol and/or sodium taurocholate. DPI characterization was performed using scanning electron microscopy for morphology, laser diffraction to evaluate the size-reduction process, and the size of the dried NP when reconstituted in aqueous media, impaction studies using a multistage liquid impactor to determine the aerodynamic performance and fine-particle fraction that is theoretically able to reach the lung, and dissolution studies to determine the solubility of ITZ. Results Scanning electron microscopy micrographs showed that the DPI particles were composed of mannitol microparticles with embedded nano- or micro-ITZ crystals. The formulations prepared from the nanosuspension exhibited good flow properties and better fine-particle fractions, ranging from 46.2% ± 0.5% to 63.2% ± 1.7% compared to the 23.1% ± 0.3% that was observed with the formulation produced from the initial microsuspension. Spray-drying affected the NP size by inducing irreversible aggregation, which was able to be minimized by the addition of mannitol and sodium taurocholate before the drying procedure. The ITZ NP-based DPI considerably increased the ITZ solubility (58 ± 2 increased to 96 ± 1 ng/mL) compared with that of raw ITZ or an ITZ microparticle-based DPI (<10 ng/mL). Conclusion Embedding ITZ NP in inhalable microparticles is a very effective method to produce DPI formulations with optimal aerodynamic properties and enhanced ITZ solubility. These formulations could be applied to other poorly water-soluble drugs and could be a very effective alternative for treating invasive pulmonary aspergillosis.

In vitro and in vivo evaluation of a dry powder endotracheal insufflator device for use in dose-dependent preclinical studies in mice

The aim of this study was to evaluate the ability of the Penn-Century Dry Powder Insufflator for mice (DP-4M) to reproducibly, uniformly, and deeply deliver dry powders for inhalation in the mouse lung. Itraconazole-based dry powder formulations produced by spray-drying were different in terms of composition (different ratios of drug and mannitol, with or without phospholipids), but relatively similar in terms of particle size and mass median aerodynamic diameter. The ability of the dry powder insufflator to disaggregate each formulation was the same, indicated by the absence of a statistically significant difference between the particle size distribution parameters, as measured by laser scattering. The emitted fraction varied in vivo compared to the in vitro condition. Fluorescent particle distribution in the lungs was uniform and reached the alveolar spaces, as visualized by fluorescent microscopy. In terms of drug recovery in lung tissue, a minimum administered powder mass (in this case ∼1 mg) was necessary to recover at least 30% of the emitted dose in the lung and to obtain reproducible pulmonary concentrations. To reduce the dose administered in the lung, it was preferable to dilute the active ingredient within the carrier instead of reducing the dry powder mass inserted in the sampling chamber. Dry powder insufflators are devices usable in dose-dependent preclinical trials but have critical parameters to efficiently deliver reproducible doses depending on the type of formulation.

Development of siRNA-loaded chitosan nanoparticles targeting Galectin-1 for the treatment of glioblastoma multiforme via intranasal administration

Galectin-1 (Gal-1) is a naturally occurring galactose-binding lectin, which is overexpressed in glioblastoma multiforme (GBM). Gal-1 is associated with tumor progression, and is a potent immune suppressor in the tumor micro-environment. To inhibit Gal-1 in GBM, an effective therapy is required that reaches the central nervous system tumor, with limited systemic effects. In this study, we report for the first time that concentrated chitosan nanoparticle suspensions can deliver small interfering RNA (siRNA) into the central nervous system tumor within hours after intranasal administration. These nanoparticles are able to complex siRNA targeting Gal-1 to a high percentage, and protect them from RNAse degradation. Moreover, a successful intracellular delivery of anti-Gal-1 siRNA resulted in a decreased expression of Gal-1 in both murine and human GBM cells. Sequence specific RNAinterference, resulted in more than 50% Gal-1 reduction in tumor bearing mice. This study indicates that the intranasal pathway is an underexplored transport route for delivering siRNA-based therapies targeting Gal-1 in the treatment of GBM.

Ophiobolin A, a sesterterpenoid fungal phytotoxin, displays higher in vitro growth-inhibitory effects in mammalian than in plant cells and displays in vivo antitumor activity.

Ophiobolin A, a sesterterpenoid produced by plant pathogenic fungi, was purified from the culture extract of Drechslera gigantea and tested for its growth-inhibitory activity in both plant and mammalian cells. Ophiobolin A induced cell death in Nicotiana tabacum L. cv. Bright Yellow 2 (TBY-2) cells at concentrations ≥10 µM, with the TBY-2 cells showing typical features of apoptosis-like cell death. At a concentration of 5 µM, ophiobolin A did not affect plant cell viability but prevented cell proliferation. When tested on eight cancer cell lines, concentrations <1 µM of ophiobolin A inhibited growth by 50% after 3 days of culture irrespective of their multidrug resistance (MDR) phenotypes and their resistance levels to pro-apoptotic stimuli. It is, thus, unlikely that ophiobolin A exerts these in vitro growth-inhibitory effects in cancer cells by activating pro-apoptotic processes. Highly proliferative human keratinocytes appeared more sensitive to the growth-inhibitory effects of ophiobolin A than slowly proliferating ones. Ophiobolin A also displayed significant antitumor activity at the level of mouse survival when assayed at 10 mg/kg in the B16F10 mouse melanoma model with lung pseudometastases. Ophiobolin A could, thus, represent a novel scaffold to combat cancer types that display various levels of resistance to pro-apoptotic stimuli and/or various MDR phenotypes.