Metastatic Melanoma: A Preclinical Model Standardization and Development of a Chitosan-Coated Nanoemulsion Containing Temozolomide to Treat Brain Metastasis.

Melanoma is the most aggressive type of skin cancer. Brain metastasis is the worst scenario in metastatic melanoma and the treatment options for these patients are limited. Temozolomide (TMZ) is a chemotherapy agent used to treat primary central nervous system tumors. Our objective was to develop chitosan-coated nanoemulsion containing temozolomide (CNE-TMZ) for nasal route administration to melanoma brain metastasis treatment. A preclinical model of metastatic brain melanoma was standardized, and the efficiency of the developed formulation was further determined in vitro and in vivo. The nanoemulsion was done by spontaneous emulsification method and the formulation was characterized by size, pH, polydispersity index, and zeta potential. Culture assessments to determine cell viability were done in the A375 human melanoma cell line. To determine the safety of formulation, healthy C57/BL6 mice were treated with a nanoemulsion without TMZ. The model in vivo used B16-F10 cells implanted by stereotaxic surgery in C57/BL6 mice brains. The results demonstrate that the preclinical model used showed to be useful to analyze the efficiency of new candidate drugs to treat melanoma brain metastasis. The chitosan-coated nanoemulsions with TMZ showed the expected physicochemical characteristics and demonstrated safety and efficacy, reducing around 70% the tumor size compared to control mice, and presenting a tendency in mitotic index reduction, becoming an interesting approach to treat melanoma brain metastasis.

CD73 in glioblastoma: Where are we now and what are the future directions?

Glioblastoma (GB) is the most aggressive type of brain tumor with heterogeneity, strong invasive ability, and high resistance to therapy due to immunosuppressive mechanisms. CD73 is an overexpressed enzyme in GB that acts via two main mechanisms: (1) CD73 acts as an adhesion protein independent of the enzymatic activity or (2) via the catalyses of AMP to adenosine (ADO) generating a strong modulatory molecule that induces alterations in the tumor cells and in the tumor microenvironment cells (TME). Taken together, CD73 is receiving attention during the last years and studies demonstrated its dual potential benefit as a target to GB therapy. Here, we review the roles of CD73 and P1 receptors (ADO receptors) in GB, the impact of CD73 in the immune interactions between tumor and other immune cells, the proposed therapeutic strategies based on CD73 regulation, and discuss the gap in knowledge and further directions to bring this approach from preclinical to clinical use.

Nasal administration of a temozolomide-loaded thermoresponsive nanoemulsion reduces tumor growth in a preclinical glioblastoma model.

Glioblastoma (GB) is the worst and most common primary brain tumor. Temozolomide (TMZ), an alkylating agent, is widely used for treating primary and recurrent high-grade gliomas. However, at least 50% of TMZ treated patients do not respond to TMZ and the development of chemoresistance is a major problem. Here, we designed a lipid nanoemulsion containing a thermoresponsive polymer (poloxamer 407) aiming to improve TMZ release into the brain via nasal delivery. Increasing amounts of poloxamer 407 were added to preformed nanoemulsions (250 nm-range) obtained by spontaneous emulsification. The influence of the polymer concentration (from 2.5% to 12.5%) and temperature on viscosity was clearly evidenced. Such effect was also noticed on the mucoadhesiveness of formulations, as well as TMZ release rate and retention/permeation through nasal porcine mucosa using Franz-type diffusion cells. From these results, a formulation containing 10% of poloxamer (NTMZ-P10) was selected for further experiments by nasal route. A significantly higher TMZ amount was observed in the brain of rats from NTMZ-P10 in comparison with controls. Finally, our results show that formulation reduced significantly tumor growth by three-fold: 103.88 ± 43.67 mm3 (for NTMZ-P10) and 303.28 ± 95.27 mm3 (control). Overall, these results suggest the potential of the thermoresponsive formulation, administered by the non-invasive nasal route, as a future effective glioblastoma treatment.

Design and synthesis of new adamantyl derivatives as promising antiproliferative agents.

A series of adamantyl carboxamide derivatives containing sulfonate or sulfonamide moiety were designed as multitargeted inhibitors of ectonucleotide pyrophosphatases/phosphodiesterases (NPPs) and carbonic anhydrases (CAs). The target compounds were investigated for their antiproliferative activity against NCI-60 cancer cell lines panel. Three main series composed of 3- and 4-aminophenol, 4-aminoaniline, and 5-hydroxyindole scaffolds were designed based on a lead compound (A). Compounds 1e (benzenesulfonyl) and 1i (4-fluorobenzenesulfonyl) of 4-aminophenol backbone exhibited the most promising antiproliferative activity. Both compounds exhibited a broad-spectrum and potent inhibition against all the nine tested cancer subtypes. Both compounds showed nanomolar IC50 values over several cancer cell lines that belong to leukemia and colon cancer such as K-562, RPMI-8226, SR, COLO 205, HCT-116, HCT-15, HT29, KM12, and SW-620 cell lines. Compounds 1e and 1i induced apoptosis in K-562 leukemia cells in a dose-dependent manner. Compound 1i showed the highest cytotoxic activity with IC50 value of 200 nM against HT29 cell line. In addition, compounds 1e and 1i were tested against normal breast cells (HME1) and normal skin fibroblast cells (F180) and the results revealed that the compounds are safe toward normal cells compared to cancers cells. Enzymatic assays against NPP1-3 and carbonic anhydrases II, IX, and XII were performed to investigate the possible molecular target(s) of compounds 1e and 1i. Furthermore, a molecular docking study was performed to predict the binding modes of compounds 1e and 1i in the active site of the most sensitive enzymes subtypes.

Achyrocline satureioides (Lam.) DC (Asteraceae) Extract-Loaded Nanoemulsions as a Promising Topical Wound Healing Delivery System: In Vitro Assessments in Human Keratinocytes (HaCaT) and HET-CAM Irritant Potential.

Achyrocline satureioides (Lam.) DC Asteraceae extracts (ASEs) have been investigated for the treatment of various skin disorders. This study reports the effects of ASE-loaded nanoemulsions (NEASE) on the cellular viability, death by necrosis, and migration of immortalized human keratinocytes (HaCaT cell line), as well as the irritant potential through the hen's egg chorioallantoic membrane test (HET-CAM). NEASE exhibited a polydispersity index above 0.12, with a droplet size of 300 nm, ζ-potential of -40 mV, and content of flavonoids close to 1 mg/mL. No cytotoxicity of the ASE was observed on HaCaT by MTT assay (up to 10 µg/mL). A significant increase of HaCaT viability was observed to NEASE (up to 5 µg/mL of flavonoids), compared to treatment with the ASE. The necrosis death evaluation demonstrated that only NEASE did not lead to cell death at all the tested concentrations. The scratch assay demonstrated that NEASE was able to increase the cell migration at low flavonoid concentrations. Finally, the HET-CAM test proved the non-irritative potential of NEASE. Overall, the results indicate the potential of the proposed formulations for topical use in wound healing, in view of their promising effects on proliferation and migration in keratinocytes, combined with an indication of the absence of cytotoxicity and non-irritating potential.

Chitosan-coated rosmarinic acid nanoemulsion nasal administration protects against LPS-induced memory deficit, neuroinflammation, and oxidative stress in Wistar rats.

Rosmarinic acid (RA) lipid-nanotechnology-based delivery systems associate with mucoadhesive biopolymers for nasal administration has arisen as a new promising neuroprotective therapy for neurodegenerative disorders (ND). We have previously demonstrated the glioprotective effect of chitosan-coated RA nanoemulsions (RA CNE) against lipopolysaccharide (LPS)-induced damage in rat astrocyte primary culture. Here, we further investigate the protective effect of RA CNE nasal administration on LPS-induced memory deficit, neuroinflammation, and oxidative stress in Wistar rats, since these in vivo studies were crucial to understand the impact of developed delivery systems in the RA neuroprotective effects. The animals were treated through nasal route with RA CNE (2 mg·mL-1), free RA (2 mg·mL-1), blank CNE, and saline (control and LPS groups) administrations (n.a., 100 µL per nostril) twice a day (7 a.m./7 p.m.) for six days. On the sixth day, the animals received the last treatments and LPS was intraperitoneally (i.p.) administrated (250 µg·kg-1). Overall results, proved for the first time that the RA CNE nasal administration elicits a neuroprotective effect against LPS-induced damage, which was associated with increased 1.6 times recognition index, decreased 5.0 and 1.9 times in GFAP+ cell count and CD11b expression, respectively, as well as increased 1.7 times SH in cerebellum and decreased 3.9 times TBARS levels in cerebral cortex in comparison with LPS group. RA CNE treatment also facilitates RA bioavailability in the brain, confirmed by RA quantification. Free RA also demonstrates a protective effect in some studied parameters, although no RA was quantified in the brain.

Antitumor action of diphenyl diselenide nanocapsules: In vitro assessments and preclinical evidence in an animal model of glioblastoma multiforme.

BACKGROUND: Gliomas are the most aggressive malignant tumors of the central nervous system. The diphenyl diselenide [(PhSe)2] is an organoselenium compound that has multiple pharmacological properties. Previous reports showed that (PhSe)2 nanoencapsulation potentiates its in vitro antitumoral action and reduces its toxicity. OBJECTIVE: In this sense, the current study was designed to further evaluate the (PhSe)2 antitumoral effect by a set of in vitro techniques using a glioma cell line as well as by an animal model of gliobastoma. METHODS: For the in vitro tests, the cell viability, propidium iodide uptake and nitrite levels of rat glioma C6 cells were determined after incubation with free (PhSe)2 or (PhSe)2-loaded nanocapsules (NC). The glioblastoma model was induced by implantation of C6 glioma cells in the right striatum of rats. Following, animals were submitted to a repeated intragastric administration treatment with (PhSe)2 or NC (PhSe)2 (1 mg/kg/day for 15 days) to assess the possible antitumor effect. MAIN FINDINGS: Both compound forms decreased the C6 glioma cells viability without causing any effect in astrocytes cells (healthy control). Importantly, the NC (PhSe)2 had superior cytotoxic effect than its free form and increased the nitrite content. Independent of the (PhSe)2 forms, the intragastric treatment reduced brain tumor size and caused neither alteration in the plasma renal and hepatic markers of function nor in the parameters of oxidative balance in brain, liver and kidneys. PRINCIPAL CONCLUSIONS: The (PhSe)2 nanoencapsulation improved its cytotoxic effect against C6 glioma cells and both compound forms attenuated the tumor development.