A DOX-loaded polymer micelle for effectively inhibiting cancer cells

Interrogating the Role of Endocytosis Pathway and Organelle Trafficking for Doxorubicin-Based Combination Ionic Nanomedicines

We have studied the endocytic mechanisms that determine subcellular localization for three carrier-free chemotherapeutic-photothermal (chemo-PTT) combination ionic nanomedicines (INMs) composed of doxorubicin (DOX) and an near-infrared (NIR) dye (ICG, IR820, or IR783). This study aims to understand the cellular basis for previously published enhanced toxicity results of these combination nanomedicines toward MCF-7 breast cancer cells. The active transport mechanism of INMs, unlike free DOX, which is known to employ passive transport, was validated by conducting temperature-dependent cellular uptake of the drug in MCF-7 cells using confocal microscopy. The internalization pathway of these INMs was further probed in the presence and absence of different endocytosis inhibitors. Detailed examination of the mode of entry of the carrier-free INMs in MCF-7 cells revealed that they are primarily internalized through clathrin-mediated endocytosis. In addition, time-dependent subcellular localization studies were also investigated. Examination of time-dependent confocal images indicated that the INMs targeted multiple organelles, in contrast to free DOX that primarily targets the nucleus. Collectively, the high cellular endocytic uptake in cancerous cells (EPR effect) and the multimode targeting ability demonstrated the main reason for the low half-maxima inhibitory concentration (IC50) value (the high cytotoxicity) of these carrier-free INMs as compared to their respective parent chemo and PTT drugs.

A new approach to the development and assessment of doxorubicin-loaded nanoliposomes for the treatment of osteosarcoma in 2D and 3D cell culture systems

Doxorubicin (DOX) is an effective anticancer drug used for the treatment of osteosarcoma. Liposomal nanocarriers for doxorubicin administration are now regarded as one of the most promising approaches to overcome multiple drug resistance and adverse side effects. The use of hydrogel as a 3D scaffold to mimic the cellular environment and provide comparable biological conditions for deeper investigations of cellular processes has attracted considerable attention. This study aimed to evaluate the impact of liposomal doxorubicin on the osteosarcoma cell line in the presence of alginate hydrogel as a three-dimensional scaffold. Different liposomal formulations based on cholesterol, phospholipids, and surfactants containing doxorubicin were developed using the thin-layer hydration approach to improve therapeutic efficacy. The final selected formulation was superficially modified using DSPE-mPEG2000. A three-dimensional hydrogel culture model with appropriate structure and porosity was synthesized using sodium alginate and calcium chloride as crosslinks for hydrogel. Then, the physical properties of liposomal formulations, such as mechanical and porosity, were characterized. The toxicity of the synthesized hydrogel was also assessed. Afterward, the cytotoxicity of nanoliposomes was analyzed on the Saos-2 and HFF cell lines in the presence of a three-dimensional alginate scaffold using the MTT assay. The results indicated that the encapsulation efficiency, the amount of doxorubicin released within 8 h, the mean size of vesicles, and the surface charge were 82.2%, 33.0%, 86.8 nm, and -4.2 mv, respectively. As a result, the hydrogel scaffolds showed sufficient mechanical resistance and suitable porosity. The MTT assay demonstrated that the synthesized scaffold had no cytotoxicity against cells, while nanoliposomal DOX exhibited marked toxicity against the Saos-2 cell line in the 3D culture medium of alginate hydrogel compared to the free drug in the 2D culture medium. Our research showed that the 3D culture model physically resembles the cellular matrix, and nanoliposomal DOX with proper size could easily penetrate into cells and cause higher cytotoxicity compared to the 2D cell culture.

A Smart Benzothiazole-Based Conjugated Polymer Nanoplatform with Multistimuli Response for Enhanced Synergistic Chemo-Photothermal Cancer Therapy

The combination of chemotherapy and phototherapy has received tremendous attention in multimodal cancer therapy. However, satisfactory therapeutic outcomes of chemo-photothermal therapy (chemo-PTT) still remain challenging. Herein, a biocompatible smart nanoplatform based on benzothiazole-linked conjugated polymer nanoparticles (CPNs) is rationally designed, for effectively loading doxorubicin (DOX) and Mo-based polyoxometalate (POM) through both dynamic chemical bond and intermolecular interactions, with an expectation to obtain new anticancer drugs with multiple stimulated responses to the tumor microenvironment (TME) and external laser irradiation. Controlled drug release of DOX from the obtained nanoformulation (CPNs-DOX-PEG-cRGD-BSA@POM) triggered by both endogenous stimulations (GSH and low pH) and exogenous laser irradiation has been well demonstrated by pharmacodynamics investigations. More intriguingly, incorporating POM into the nanoplatform not only enables the nanomedicine to achieve mild hyperthermia but also makes it exhibit self-assembly behavior in acidic TME, producing enhanced tumor retention. Benefiting from the versatile functions, the prepared CPNs-DOX-PEG-cRGD-BSA@POM exhibited excellent tumor targeting and therapeutic effects in murine xenografted models, showing great potential in practical cancer therapy.

Syntheses of Polypeptides and Their Biomedical Application for Anti-Tumor Drug Delivery

Polypeptides have attracted considerable attention in recent decades due to their inherent biodegradability and biocompatibility. This mini-review focuses on various ways to synthesize polypeptides, as well as on their biomedical applications as anti-tumor drug carriers over the past five years. Various approaches to preparing polypeptides are summarized, including solid phase peptide synthesis, recombinant DNA techniques, and the polymerization of activated amino acid monomers. More details on the polymerization of specifically activated amino acid monomers, such as amino acid N-carboxyanhydrides (NCAs), amino acid N-thiocarboxyanhydrides (NTAs), and N-phenoxycarbonyl amino acids (NPCs), are introduced. Some stimuli-responsive polypeptide-based drug delivery systems that can undergo different transitions, including stability, surface, and size transition, to realize a better anti-tumor effect, are elaborated upon. Finally, the challenges and opportunities in this field are briefly discussed.

Recent Advances in the Local Drug Delivery Systems for Improvement of Anticancer Therapy

The conventional anticancer chemotherapies not only cause serious toxic effects, but also produce resistance in tumor cells exposed to long-term therapy. Usually, the killing of metastasized cancer cells requires long-term therapy with higher drug doses, because the cancer cells develop resistance due to the induction of poly-glycoproteins (P-gps) that act as a transmembrane efflux pump to transport drugs out of the cells. During the last few decades, scientists have been exploring new anticancer drug delivery systems such as microencapsulation, hydrogels, and nanotubes to improve bioavailability, reduce drug-dose requirement, decrease multiple drug resistance, and to save normal cells as non-specific targets. Hopefully, the development of novel drug delivery vehicles (nanotubes, liposomes, supramolecules, hydrogels, and micelles) will assist to deliver drug molecules at the specific target site and reduce the undesirable side effects of anticancer therapies in humans. Nanoparticles and lipid formulations are also designed to deliver small drug payload at the desired tumor cell sites for their anticancer actions. This review will focus on the recent advances in the drug delivery systems, and their application in treating different cancer types in humans.

Silk Sericin-Polylactide Protein-Polymer Conjugates as Biodegradable Amphiphilic Materials and Their Application in Drug Release Systems

Silk sericin (SS) is a byproduct of silk production. In order to transform it into value-added products, sericin can be used as a biodegradable and pH-responsive building block in drug delivery materials. To this end, amphiphilic substances were synthesized via the conjugation of hydrophobic polylactide (PLA) to the hydrophilic sericin using a bis-aryl hydrazone linker. PLA was esterified with a terephthalaldehydic acid to obtain aromatic aldehyde terminated PLA (PLA-CHO). In addition, lysine groups of SS were modified with the linker succinimidyl-6-hydrazino-nicotinamide (S-HyNic). Then, both macromolecules were mixed to form the amphipilic protein-polymer conjugate in buffer-DMF solution. The formation of bis-aryl hydrazone linkages was confirmed and quantified by UV-vis spectroscopy. SS-PLA conjugates self-assembled in water into spherical multicompartment micelles with a diameter of around 100 nm. Doxorubicin (DOX) was selected as a model drug for studying the pH-dependent drug release from SS-PLA nanoparticles. The release rate of the encapsulated drug was slower than that of the free drug and dependent on pH, faster at pH 5.0, and it resulted in a larger cumulative amount of drug released than at physiological pH of 7.4. The SS-PLA conjugate of high PLA branches showed smaller particle size and lower loading capacity than the one with low PLA branches. Both SS-PLA conjugates had negligible cytotoxicity, whereas after loading with DOX, the SS-PLA micelles were highly toxic for the human liver carcinoma immortalized cell line HepG2. Therefore, the SS-based biodegradable amphiphilic material showed great potential as a drug carrier for cancer therapy.

Hypoxia-Responsive Polymeric Micelles for Enhancing Cancer Treatment

Polymeric drug vectors have shown great potentials in cancer therapy. However, intelligent controlled release of drugs has become a major challenge in nanomedicine research. Hypoxia-responsive polymeric micelles have received widespread attention in recent years due to the inherent hypoxic state of tumor tissue. In this study, a novel diblock polymer consisting of polyethylene glycol and poly[glutamic acid (3-(2-nitro-imidazolyl)-propyl)] was synthesized and self-assembled into hypoxia-responsive polymeric micelles for the controlled release of doxorubicin (DOX). The cell experiments demonstrated that DOX-loaded micelles had a stronger killing capacity on tumor cells under hypoxic conditions, while the blank micelles had good biocompatibility. All the experiments indicate that our hypoxia-responsive polymeric micelles have a great potential for enhanced cancer treatment.

The potential of micelleplexes as a therapeutic strategy for osteosarcoma disease

Osteosarcoma (OS) is a rare aggressive bone, presenting low patient survival rate, high metastasis and relapse occurrence, mostly due to multi-drug resistant cells. To surpass that, the use of nanomedicine for the targeted delivery of genetic material, drugs or both have been extensively researched. In this review, we address the current situation of the disorder and some gene therapy options in the nanomedicine field that have been investigated. Among them, polymeric micelles (PM) are an advantageous therapeutic alternative highly explored for OS, as they allow for the targeted transportation of poorly water-soluble drugs to cancer cells. In addition, micelleplexes are PMs with cationic properties with promising features, such as the possibility for a dual therapy, which have made them an attractive research subject. The aim of this review article is to elucidate the application of a micelleplex formulation encapsulating the underexpressed miRNA145 to achieve an active targeting to OS cells and overcome multi-drug resistance, as a new and viable therapeutic strategy.

Redox Stimuli Delivery Vehicle Based on Transferrin-Capped MSNPs for Targeted Drug Delivery in Cancer Therapy

Cancer has become one of the major diseases of human health around the world. Conventional antitumor drugs cannot specifically target cancers and result in serious side effects. To achieve better therapy, innovative functional drug delivery platforms that will aid specific targeting for cancer cells need to be developed. In this study, transferrin (Tf), which can target cancer cells, is covalently anchored onto the surface of MSNPs via disulfide linkage, which is used for glutathione-triggered intracellular drug release in tumor cells. The successful functionalization of redox-responsive MSNPs is confirmed by using BET/BJH, TEM, TGA, NMR, and FT-IR (BET, Brunauer-Emmett-Teller; BJH, Barrett-Joyner-Halenda). In addition, polyethylene glycol (PEG) is further grafted onto the surface of MSNPs to improve the biocompatibility and stability under physiological conditions for longer blood circulation. Our in vitro studies demonstrate that DOX-loaded MSNP-SS-Tf@PEG can selectively be internalized into cancer cells via Tf/Tf receptor interactions, and then, DOX is released in HT-29 and MCF-7 cells triggered by high GSH concentration in tumor cells. Remarkably, in vivo studies demonstrate that DOX-loaded MSNP-SS-Tf@PEG can significantly inhibit tumor growth with minimized side effects through cell apoptosis determined by TUNEL assay, whereas MSNP-SS-Tf@PEG revealed no significant inhibition. In conclusion, DOX-MSNP-SS-Tf@PEG with active targeting moieties and a redox-responsive strategy has been demonstrated as a great effective drug carrier for tumor therapy in vitro and in vivo.

Dual-generation dendritic mesoporous silica nanoparticles for co-delivery and kinetically sequential drug release

Although multi-drug synergetic therapy is increasingly important in clinical application, sophisticated delivery systems with the ability to deliver multiple drugs and realize sequential release with independently tunable kinetics at different stages are highly desirable. In this study, a dual-generation mesoporous silica nanoparticle (DAMSN) with three-dimensional dendrimer-like structure as an adaptable dual drug delivery system is developed. The DAMSN was synthesized via a heterogeneous interfacial reaction and was of uniformly spherical morphology (150–170 nm) with dendritic structures and hierarchical pores (inner pore, 3.5 nm; outer pore, 8.3 nm). And the inner generation of DAMSN was modified with 3-aminopropyltriethoxysilane (APTMS). The IBU and BSA as model drugs were loaded into the inner generation via covalent conjugation and the outer generation by electrostatic adsorption, respectively. Intriguingly, DAMSN underwent a rapid bio-degradation for about 4 days, partly due to its center-radial dendritic channel structure. The release results showed that IBU was of a typical two-phase release profile with almost zero release in the first 12 h and more sustained release for the following 88 h, while BSA was sustained over a long period of 100 h. Notably, the release behaviors of both drugs can be independently tailored by changing the intrinsic properties of the DAMSN. In addition, DAMSN exhibited good bio-compatibility. These results indicated that the dual-generation, dendrimer-like MSN structure could spatiotemporally present different drugs to realize sequential drug release, and has potential use in the field of tissue engineering and regenerative medicine.

The designed DAMSN could simultaneously load IBU and BSA, and realize sequential drug release efficiently.