New doxorubicin nanocarriers based on cyclodextrins

Codelivery of Doxorubicin and p53 Gene by β-Cyclodextrin-Based Supramolecular Nanoparticles Formed via Host-Guest Complexation and Electrostatic Interaction

We developed a supramolecular system for codelivery of doxorubicin (Dox) and p53 gene based on a β-CD-containing star-shaped cationic polymer. First, a star-shaped cationic polymer consisting of a β-CD core and 3 arms of oligoethylenimine (OEI), named CD-OEI, was used to form a supramolecular inclusion complex with hydrophobic Dox. The CD-OEI/Dox complex was subsequently used to condense plasmid DNA via electrostatic interactions to form CD-OEI/Dox/DNA polyplex nanoparticles with positive surface charges that enhanced the cellular uptake of both Dox and DNA. This supramolecular drug and gene codelivery system showed high gene transfection efficiency and effective protein expression in cancer cells. The codelivery of Dox and DNA encoding the p53 gene resulted in reduced cell viability and enhanced antitumor effects at low Dox concentrations. With its enhanced cellular uptake and anticancer efficacy, the system holds promise as a delivery carrier for potential combination cancer therapies.

Hyaluronan-Cyclodextrin Conjugates as Doxorubicin Delivery Systems

In the last years, nanoparticles based on cyclodextrins have been widely investigated for the delivery of anticancer drugs. In this work, we synthesized nanoparticles with a hyaluronic acid backbone functionalized with cyclodextrins under green conditions. We functionalized hyaluronic acid with two different molecular weights (about 11 kDa and 45 kDa) to compare their behavior as doxorubicin delivery systems. We found that the new hyaluronan-cyclodextrin conjugates increased the water solubility of doxorubicin. Moreover, we tested the antiproliferative activity of doxorubicin in the presence of the new cyclodextrin polymers in SK-N-SH and SK-N-SH-PMA (over-expressing CD44 receptor) cancer cells. We found that hyaluronan-cyclodextrin conjugates improved the uptake and antiproliferative activity of doxorubicin in the SK-N-SH-PMA compared to the SK-N-SH cell line at the ratio 8/1 doxorubicin/polymer. Notably, the system based on hyaluronan (45 kDa) was more effective as a drug carrier and significantly reduced the IC50 value of doxorubicin by about 56%. We also found that hyaluronic acid polymers determined an improved antiproliferative activity of doxorubicin (IC50 values are on average reduced by about 70% of free DOXO) in both cell lines at the ratio 16/1 doxorubicin/polymer.

Mitochondria-targeting nano therapy altering IDH2-mediated EZH2/EZH1 interaction as precise epigenetic regulation in glioblastoma

Glioblastoma (GBM) is a complex brain cancer with frequent relapses and high mortality and still awaits effective treatment. Mitochondria dysfunction is a pathogenic condition in GBM and could be a prime therapeutic target for ceasing GBM progression. Strategies to overcome brain solid tumor barriers and selectively target mitochondria within specific cell types may improve GBM treatment. Here, we present hypericin-conjugated gold nanoparticles (PEG-AuNPs@Hyp) where hypericin is a mitochondrion-targeting agent exhibiting multimodal therapy by critically impacting the IDH2 gene (Isocitrate dehydrogenase) and its interaction with polycomb methyltransferase EZH1/2 for GBM therapy. It significantly localizes in mitochondria by enhanced cellular uptake in the human GBM cell lines/three-dimensional (3D) culture model under red-light exposure. It triggers oxidative stress and changes the mitochondrial potential, with increased Bax/Bcl2 ratio enhancing GBM cell death. The suppressed expression of mutated IDH2 and polycomb group of proteins upon PEG-AuNPs@Hyp/light exposure regulates mitochondria-targeting-mediated GBM metabolism with epigenetic repression of complex machinery function. Polyubiquitination and proteasomal degradation of EZH1 indicate the implication of these polycomb proteins in GBM progression. Chromatin immunoprecipitation reveals the IDH2 and EZH1/EZH2 direct interaction, confirming the role played by IDH2 in modulating the expression of EZH1 and EZH2. In vivo studies further displayed better tumor ablation in a GBM tumor-bearing nude mouse model. The present multimodal nanoformulation compromised the functional dependency of polycomb on mitochondrial IDH2 and established the mechanism of GBM inhibition.

Functionalization of β-cyclodextrin with a urea-based PSMA ligand and preliminary studies on targeting prostate cancer cells

Targeted delivery of drugs into specific cancer cells is an effective way to enhance the efficacy and minimize the side effects of therapy. Prostate malignant cells overexpress the prostate-specific membrane antigen (PSMA), a membrane protein that may be a valid target for selective drug administration. To target prostate cancer cells, a β-cyclodextrin perfunctionalised with dipeptide-like urea arms, a well-established mimic of a selective ligand against PSMA, is herein reported, to develop a multivalent drug delivery and targeting system. Firstly, fluorescein was used to validate the system on cells that express high levels of PSMA (prostate tumoral cells, LNCap) or very low levels of PSMA (non-tumoral cells, Hek293T). Then, the antineoplastic agent doxorubicin complexed with β-cyclodextrin functionalized with PSMA-like ligand takes less time to induce cytotoxicity on LNCap cells compared to doxorubicin alone. This might represent a promising drug-delivery approach to selectively target prostate cancer cells.

Characteristic of Cyclodextrins: Their Role and Use in the Pharmaceutical Technology

About 40% of newly-discovered entities are poorly soluble in water, and this may be an obstacle in the creation of new drugs. To address this problem, the present review article examines the structure and properties of cyclodextrins and the formation and potential uses of drug - cyclodextrin inclusion complexes. Cyclodextrins are cyclic oligosaccharides containing six or more D-(+)- glucopyranose units linked by α-1,4-glycosidic bonds, which are characterized by a favourable toxicological profile, low local toxicity and low mucous and eye irritability; they are virtually non-toxic when administered orally. They can be incorporated in the formulation of new drugs in their natural form (α-, β-, γ-cyclodextrin) or as chemically-modified derivatives. They may also be used as an excipient in drugs delivered by oral, ocular, dermal, nasal and rectal routes, as described in the present paper. Cyclodextrins are promising compounds with many beneficial properties, and their use may be increasingly profitable for pharmaceutical scientists.

Enhanced therapeutic index of liposomal doxorubicin Myocet locally delivered by fibrin gels in immunodeficient mice bearing human neuroblastoma

Caelyx and Myocet are clinically used liposomal forms of doxorubicin (Dox). To explore ways to improve their therapeutic index, we have studied their activity in vitro and in vivo when locally delivered by fibrin gels (FBGs). In vivo local toxic and anti-tumour activities of loaded FBGs were assessed in two immunodeficient mouse orthotopic human neuroblastoma (NB) models after application in the visceral space above the adrenal gland, either still tumour-bearing or after tumour removal. In parallel, in vitro assays were used to mimic the in vivo overlaying of FBGs on the tumour surface. FBGs were prepared with different concentrations of fibrinogen (FG) and clotted in the presence of Ca2+ and thrombin. The in vitro assays showed that FBGs loaded with Myocet possess a cytotoxic activity against NB cell lines generally greater than those loaded with free Dox or Caelyx. In vivo FBGs loaded with Myocet showed lower general and local toxicities as compared to gels loaded with Caelyx or free Dox, and also to free Dox administered i.v. (all treatments with Dox at 2.5 mg/Kg). The anti-tumour activity, evaluated in the two mouse orthotopic NB models of adjuvant and neo-adjuvant therapy, resulted in a better performance of FBGs loaded with Myocet compared to the other local (FBGs loaded with Caelyx or free Dox) or systemic (free Dox) treatments (administered at 2.5 and 5 mg/Kg Dox). Specifically, the application of FBGs at 40 mg/mL in the adjuvant model caused 92 % tumour volume reduction, while by the neo-adjuvant application of FBGs at 22 mg/mL a re-growing tumour volume reduction of 89 % was obtained. Taken together, our in vitro and in vivo results indicate a significantly higher activity for the FBGs loaded with Myocet. In particular, the lower toicity coupled with the higher anti-tumour activity on both the local treatment modalities strongly suggest a better therapeutic index when Myocet is administered through FBGs. Therefore, FBGs loaded with Myocet may be considered as a possible new tool for the loco-regional treatment of NB or even other tumour histotypes treatable by loco-regional chemotherapy.

Fibrin gels entrapment of a doxorubicin-containing targeted polycyclodextrin: Evaluation of in vivo antitumor activity in orthotopic models of human neuroblastoma

In vivo local antitumor activity of fibrin gels (FBGs) loaded with the poly-cyclodextrin oCD-NH₂/Dox, compared to free Dox, was evaluated in two mouse orthotopic neuroblastoma (NB) models, after positioning of the releasing devices in the visceral space. FBGs were prepared at the fibrinogen (FG) concentrations of 22 and 40 mg/ml clotted in the presence of 0.81 mM/mg FG Ca²⁺ and 1.32 U/mg FG thrombin. Our results indicate that FBGs loaded with oCD-NH₂/Dox and applied as neoadjuvant loco-regional treatment, show an antitumor activity significantly greater than that displayed by the same FBGs loaded with identical dose of Dox or after free Dox administered intra venous (iv). In particular, FBGs prepared at 40 mg/ml showed a slightly lower antitumor activity, although after their positioning we observed a significant initial reduction of tumor burden lasting for several days after gel implantation. FBGs at 22 mg/ml loaded with oCD-NH₂/Dox and applied after tumor removal (adjuvant treatment model) showed a significantly better antitumor activity than the iv administration of free Dox, with 90% tumor regrowth reduction compared to untreated controls. In all cases the weight loss post-treatment was limited after gel application, although in the adjuvant treatment the loss of body weight lasted longer than in the other treatment modality. In accordance with our recent published data on the low local toxic effects of FBGs, the present findings also underline an increase of the therapeutic index of Dox when locally administered through FBGs loaded with the oCD-NH₂/Dox complex.

A NIR-responsive indocyanine green-genistein nanoformulation to control the polycomb epigenetic machinery for the efficient combinatorial photo/chemotherapy of glioblastoma

Combinatorial photodynamics and chemotherapy have drawn enormous attention as therapeutic modalities via precise stimuli-responsive drug delivery for glioblastoma, which can overcome the limitations associated with conventional therapies. Herein, we have prepared an indocyanine green tagged, genistein encapsulated casein nanoformulation (ICG-Gen@CasNPs) that exhibits the near infra-red region responsive controlled release of genistein and enhanced cellular uptake in the human glioblastoma monolayer and a three-dimensional raft culture model via the enhanced retention effect. ICG-Gen@CasNPs, with the integrated photosensitizer indocyanine green within the nanoformulation, triggered oxidative stress, activating the apoptosis cascade, promoting cell cycle arrest and damaging the mitochondrial membrane potential, collectively directing glioblastoma cell death. The suppression of the polycomb group of proteins in the glioblastoma upon ICG-Gen@CasNPs/NIR exposure revealed the involvement of the epigenetic repression complex machinery in the regulation. Furthermore, ICG-Gen@CasNPs/PDT/PTT directed ubiquitination and proteasomal degradation of EZH2 and BMI1 indicates the implication of the polycomb in conferring glioblastoma survival. The increased activation of the apoptotic pathways and the generation of cellular reactive oxygen species upon inhibiting the expression of EZH2 and BMI1 strengthen our observations. It is worth noting that ICG-Gen@CasNPs robustly accumulated in the brain after crossing the blood-brain barrier, which represents the eminent biocompatibility and means that the system is devoid of any nonspecific toxicity in vivo. Moreover, a superior anti-tumor effect was demonstrated on a three-dimensional glioma spheroid model. Thus, this combinatorial chemo/photodynamic therapy revealed that ICG-Gen@CasNPs mediated epigenetic regulation, which is a crucial molecular mechanism of GBM suppression.

Fibrin Gels Entrapment of a Poly-Cyclodextrin Nanocarrier as a Doxorubicin Delivery System in an Orthotopic Model of Neuroblastoma: Evaluation of In Vitro Activity and In Vivo Toxicity

PURPOSE

Fibrin gels (FBGs) are potential delivery vehicles for many drugs, and can be easily prepared from purified components. We previously demonstrated their applicability for the release of different doxorubicin (Dox) nanoparticles used clinically or in an experimental stage, such as its inclusion complex with the amino β-cyclodextrin polymer (oCD-NH₂/Dox). Here we extend these studies by in vitro and in vivo evaluations.

METHODS

An in vitro cytotoxicity model consisting of an overlay of a neuroblastoma (NB) cell-containing agar layer above a drug-loaded FBG layer was used. Local toxicity in vivo (histology and blood analysis) was studied in a mouse orthotopic NB model (SHSY5YLuc⁺ cells implanted into the left adrenal gland).

RESULTS

In vitro data show that FBGs loaded with oCD-NH₂/Dox have a slightly lower cytotoxicity against NB cell lines than those loaded with Dox. Fibrinogen (FG), and Ca²⁺ concentrations may modify this activity. In vivo data support a lower general and local toxicity for FBGs loaded with oCD-NH₂/Dox than those loaded with Dox.

CONCLUSION

Our results suggest a possible increase of the therapeutic index of Dox when locally administered through FBGs loaded with oCD-NH₂/Dox, opening the possibility of using these releasing systems for the treatment of neuroblastoma.

Functionalized β-Cyclodextrin Immobilized on Ag-Embedded Silica Nanoparticles as a Drug Carrier

Cyclodextrins (CDs) have beneficial characteristics for drug delivery, including hydrophobic interior surfaces. Nanocarriers with β-CD ligands have been prepared with simple surface modifications as drug delivery vehicles. In this study, we synthesized β-CD derivatives on an Ag-embedded silica nanoparticle (NP) (SiO₂@Ag NP) structure to load and release doxorubicin (DOX). Cysteinyl-β-CD and ethylenediamine-β-CD (EDA-β-CD) were immobilized on the surface of SiO₂@Ag NPs, as confirmed by transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectrophotometry, and Fourier transform infrared (FTIR) spectroscopy. DOX was introduced into the β-CD on the SiO₂@Ag NPs and then successfully released. Neither cysteinyl-β-CD and EDA-β-CD showed cytotoxicity, while DOX-loaded cysteinyl-β-CD and EDA-β-CD showed a significant decrease in cell viability in cancer cells. The SiO₂@Ag NPs with β-CD provide a strategy for designing a nanocarrier that can deliver a drug with controlled release from modified chemical types.

Cyclodextrin complexes: Perspective from drug delivery and formulation

Cyclodextrins (CDs) have been widely investigated as a unique pharmaceutical excipient for past few decades and is still explored for new applications. They are highly versatile oligosaccharides which possess multifunctional characteristics, and are mainly used to improve the physicochemical stability, solubility, dissolution rate, and bioavailability of drugs. Stability constant, factors affecting complexation, techniques to enhance complexation efficiency, the preparation methods for molecular inclusion complexes and release of guest molecules are discussed in brief. In addition, different CD derivatives and their pharmacokinetics are elaborated. Further, the significance of CD complex in aqueous solubility, dissolution and bioavailability, stability, and taste masking is explained. The recent advancement of CDs in developing various drug delivery systems is enlightened. Indeed, the potential of CDs by means of inclusion complex formation have widen the applicability of these materials in various drug delivery systems including ocular, osmotic, mucoadhesive, transdermal, nasal, and targeted delivery systems. Feasibility studies have been performed on the benefit of these cyclic oligomers as nanocarriers, a strategy that can modify the drugs with improved physicochemical properties. Studies also demonstrated the feasibility of CDs to self-assemble in the form of stable nanoaggregates, which may extend the scope of CDs in drug delivery to the continually expanding list of new drug entities.

Cyclodextrin polymers decorated with RGD peptide as delivery systems for targeted anti-cancer chemotherapy

Polymeric cyclodextrin-based nanoparticles are currently undergoing clinical trials as nanotherapeutics. Using a non-covalent approach, we decorated two cross-linked cyclodextrin polymers of different molecular weights with an RGD peptide derivative to construct a novel carrier for the targeted delivery of doxorubicin. RGD is the binding sequence for the integrin receptor family that is highly expressed in tumour tissues. The assembled host-guest systems were investigated using NMR and DLS techniques. We found that, in comparison with free doxorubicin or the binary complex doxorubicin/cyclodextrin polymer, the RGD units decorating the cyclodextrin-based nanosystems improved the selectivity and cytotoxicity of the complexed doxorubicin towards cultured human tumour cell lines. Our results suggest that the nanocarriers under study may contribute to the development of new platforms for cancer therapy.

pH-Sensitive Co-Adsorption/Release of Doxorubicin and Paclitaxel by Carbon Nanotube, Fullerene, and Graphene Oxide in Combination with N-isopropylacrylamide: A Molecular Dynamics Study

Nanotechnology based drug delivery systems for cancer therapy have been the topic of interest for many researchers and scientists. In this research, we have studied the pH sensitive co-adsorption and release of doxorubicin (DOX) and paclitaxel (PAX) by carbon nanotube (CNT), fullerene, and graphene oxide (GO) in combination with N-isopropylacrylamide (PIN). This simulation study has been performed by use of molecular dynamics. Interaction energies, hydrogen bond, and gyration radius were investigated. Results reveal that, compared with fullerene and GO, CNT is a better carrier for the co-adsorption and co-release of DOX and PAX. It can adsorb the drugs in plasma pH and release it in vicinity of cancerous tissues which have acidic pH. Investigating the number of hydrogen bonds revealed that PIN created many hydrogen bonds with water resulting in high hydrophilicity of PIN, hence making it more stable in the bloodstream while preventing from its accumulation. It is also concluded from this study that CNT and PIN would make a suitable combination for the delivery of DOX and PAX, because PIN makes abundant hydrogen bonds and CNT makes stable interactions with these drugs.

Linear polymers of β and γ cyclodextrins with a polyglutamic acid backbone as carriers for doxorubicin

Cyclodextrins have been used to encapsulate drugs improving their stability and efficiently regulating their release. Polymeric nanoparticles containing cyclodextrins are currently undergoing clinical trials as nanotherapeutics. In this context, we have synthesized new linear polymers based on polyglutamic acid with pendant β- or γ-cyclodextrins, using a high yield reaction route. The new polymers with an average number of about 17 cyclodextrin cavities were characterized (NMR, MALDI-MS, DLS) and tested as carriers of doxorubicin in human tumor cells. They can include doxorubicin, and the inclusion complexes show antiproliferative activity in human tumor cells.