Optimization of Tyrosine Kinase Inhibitor-Loaded Gold Nanoparticles for Stimuli-Triggered Antileukemic Drug Release

Tyrosine kinase inhibitor (TKI) therapy is gaining attraction in advanced cancer therapeutics due to the ubiquity of kinases in cell survival and differentiation. Great progress was made in the past years in identifying tyrosine kinases that can function as valuable molecular targets and for the entrapment of their corresponding inhibitors in delivery compounds for triggered release. Herein we present a class of drug-delivery nanocompounds based on TKI Midostaurin-loaded gold nanoparticles that have the potential to be used as theranostic agents for the targeting of the FMS-like tyrosine kinase 3 (FLT3) in acute myeloid leukemia. We optimized the nanocompounds' formulation with loading efficiency in the 84-94% range and studied the drug release behavior in the presence of stimuli-responsive polymers. The therapeutic activity of MDS-loaded particles, superior to that of the free drug, was confirmed with toxicities depending on specific dosage ranges. No effect was observed on FLT3-negative cells or for the unloaded particles. Beyond druggability, we can track this type of nanocarrier inside biological structures as demonstrated via dark field microscopy. These properties might contribute to the facilitation of personalized drug dosage administration, critical for attaining a maximal therapeutic effect.

Hybrid Clustered Nanoparticles for Chemo-Antibacterial Combinatorial Cancer Therapy

Background: A great number of therapeutic limitations, such as chemoresistance, high dosage, and long treatments, are still present in cancer therapy, and are often followed by side effects such as infections, which represent the primary cause of death among patients. Methods: We report pH- and enzymatic-responsive hybrid clustered nanoparticles (HC-NPs), composed of a PCL polymeric core loaded with an anticancer drug, such as Imatinib Mesylate (IM), and coated with biodegradable multilayers embedded with antibacterial and anticancer baby-ship silver NPs, as well as a monoclonal antibody for specific targeting of cancer cells conjugated on the surface. Results: The HC-NPs presented an onion-like structure that serially responded to endogenous stimuli. After internalization into targeted cancer cells, the clustered nanoparticles were able to break up, thanks to intracellular proteases which degraded the biodegradable multilayers and allowed the release of the baby-ship NPs and the IM loaded within the pH-sensible polymer present inside the mothership core. In vitro studies validated the efficiency of HC-NPs in human chronic leukemic cells. This cellular model allowed us to demonstrate specificity and molecular targeting sensitivity, achieved by using a combinatorial approach inside a single nano-platform, instead of free administrations. The combinatory effect of chemotherapic drug and AgNPs in one single nanosystem showed an improved cell death efficacy. In addition, HC-NPs showed a good antibacterial capacity on Gram-negative and Gram-positive bacteria. Conclusions: This study shows an important combinatorial anticancer and antimicrobial effect in vitro.

Diosgenin-conjugated PCL–MPEG polymeric nanoparticles for the co-delivery of anticancer drugs: design, optimization, in vitro drug release and evaluation of anticancer activity

In this study, a polymeric nanoparticle-mediated dual anti-cancer drug delivery system was designed and developed.

Mesoporous bioactive glass-polyurethane nanocomposites as reservoirs for sustained drug delivery

The materials capable of sustained drug release are highly desired in the biomedical field, and for this purpose, mesoporous bioactive glass (MBG) and polyurethanes (PUs) are being used along with various other materials. However, MBG is highly brittle and PUs suffer from the lower tensile strength value. Therefore, to overcome these shortcomings, bioactive nanocomposites were designed and fabricated by using MBG and biodegradable PUs. MBG with variable percentages was used as filler in arginine and starch-based PU matrices. The structural, mechanical and physicochemical properties were evaluated by fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), stress-strain curves and MTT assay. All the nanocomposites exhibited high cell viability (96-100%) and are therefore designated as biocompatible. The young's modulus is in the range of 0.5-0.8 MPa, which perfectly matches with that of cancellous bones. The nanocomposites were further studied for sustained drug delivery of an anti-cancer drug, imatinib. There was no burst effect and 52-84% of the drug was released over a period of three weeks. Consequently, these nanocomposites behaved as reservoirs for sustained drug release and can be applied for reducing the dose frequency where required.

Wool-Like Hollow Polymeric Nanoparticles for CML Chemo-Combinatorial Therapy

Chronic myeloid leukaemia (CML) is caused by the BCR-ABL oncogene, which encodes the constitutively active BCR-ABL tyrosine kinase. Targeted therapy with tyrosine-kinase inhibitors induces a partial cytogenetic response in most patients. Nanosystems can represent an opportunity for combinatorial therapy with the capacity to simultaneously release different therapeutic agents, checking the pharmacokinetic properties. In this work, we have developed a novel poly-(ε-caprolactone) (PCL) nanosystem for combinatorial therapy in CML, composed of a biodegradable pH sensitive core releasing Nilotinib (Nil) and an enzymatic sensitive outer shell releasing Imatinib Mesylate (IM), resulting in wool-like nanoparticles (NPs). The resulting double loaded wool-like hollow PCL NPs showed a high dual-drug encapsulation efficiency, pH and enzymatic sensitivity and synchronized drug release capability. The combinatorial delivery of IM and Nil exhibited an importantly reduced IC50 value of IM and Nil on leukaemia cells compared to single free drugs administration. In vitro results, showed that combinatorial nanomixures preserved the biological activity of loaded drugs for extensive time windows and led to a constant release of active drug. In addition, the combination of IM and Nil in single PCL NPs have shown a more therapeutic efficiency at a low dose with respect to the single drug nanomixures, confirming that both drugs reached the target cell precisely, maximizing the cytotoxicity while minimizing the chances of cell resistance to drugs.

Membrane perturbation through novel cell-penetrating peptides influences intracellular accumulation of imatinib mesylate in CML cells

Chronic myeloid leukemia is a stem cell disease with the presence of Philadelphia chromosome generated through reciprocal translocation of chromosome 9 and 22. The use of first- and second-generation tyrosine kinase inhibitors has been successful to an extent. However, resistance against such drugs is an emerging problem. Apart from several drug-resistant mechanisms, drug influx/efflux ratio appears to be one of the key determinants of therapeutic outcomes. In addition, intracellular accumulation of drug critically depends on cell membrane fluidity and lipid raft dynamics. Previously, we reported two novel cell-penetrating peptides (CPPs), namely, cationic IR15 and anionic SR11 present in tryptic digest of Abrus agglutinin. Here, the potential of IR15 and SR11 to influence intracellular concentration of imatinib has been evaluated. Fluorescent correlation spectroscopy and lifetime imaging were employed to map membrane fluidity and lipid raft distribution following peptide-drug co-administration. Results show that IR15 and SR11 are the two CPPs which can modulate membrane fluidity and lipid raft distribution in K562 cells. Both IR15 and SR11 significantly reduce the viability of CML cells in the presence of imatinib by increasing the intracellular accumulation of the drug.

Label-free visualization of nilotinib-functionalized gold nanoparticles within single mammalian cells by C60- SIMS imaging

Obtaining a comprehensive grasp of the behavior and interaction of pharmaceutical compounds within single cells provides some of the fundamental details necessary for more effective drug development. In particular, the changes ensuing in the carrier, drug, and host environment in targeted drug therapy applications must be explored in greater detail, as these are still not well understood. Here, nilotinib-functionalized gold nanoparticles are examined within single mammalian cells with use of imaging cluster secondary ion mass spectrometry in a model study designed to enhance our understanding of what occurs to these particles once that have been internalized. Nilotinib, several types of gold nanoparticles, and the functionalized combination of the two were surveyed and successfully imaged within single cells to determine uptake and performance. Both nilotinib and the gold particle are able to be distinguished and visualized in the functionalized nanoparticle assembly within the cell. These compounds, while both internalized, do not appear to be present in the same pixels of the chemical image, indicating possible cleavage of nilotinib from the particle after cell uptake. The method provided in this work is a direct measurement of uptake and subcellular distribution of an active drug and its carrier within a framework. The results obtained from this study have the potential to be applied to future studies to provide more effective and specific cellular delivery of a relevant pharmaceutical compound.

In vitro effect of imatinib mesylate loaded on polybutylcyanoacrylate nanoparticles on leukemia cell line K562

The study aimed to prepare imatinib mesylate-loaded polybutylcyanoacrylate (PBCA) nanoparticles and evaluate their efficacy on leukemia cell line K562. The formulation was prepared by miniemulsion polymerization technique. Nanoparticles were characterized by dynamic light scattering (DLS), spectrophotometry, Fourier transform infrared spectroscopy (FTIR), dialysis membrane, and 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) techniques. Nanoscale particles with high encapsulation efficiency (86%) and physical entrapment of drug were observed. In addition, nanoparticles showed suitable drug retention capability and potentiate the cytotoxicity effects of imatinib mesylate. Findings of study suggested PBCA nanoparticles are promising carrier for imatinib mesylate delivery to leukemia cell line K562.

A vegetable oil-based organogel for use in pH-mediated drug delivery

Organogels prepared with vegetable oils as the liquid organic phase present an excellent platform for the controlled delivery of hydrophobic guest molecules. We disclose a graft copolymer comprised of a poly(L-serine) backbone linked to alkane side-chains by hydrolytically susceptible ester bonds, that is capable of gelating edible safflower oil. The thermoresponsive organogel formed, which is non-cytotoxic, is capable of withholding guest molecules before undergoing targeted disassembly upon incubation in solutions of acidic pH, permitting the directed release of payload molecules. The presented material offers an extremely promising candidate for the controlled delivery of hydrophobic agents within acidic environments, such as cancer tumour sites.