Drug and gene co-delivery systems for cancer treatment

A Cationic Smart Copolymer for DNA Binding

A new block copolymer with a temperature-responsive block and a cationic block was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization, with good control of its size and composition. The first block is composed by di(ethylene glycol) methyl ether methacrylate (DEGMA) and oligo(ethylene glycol) methyl ether methacrylate (OEGMA), with the ratio DEGMA/OEGMA being used to choose the volume phase transition temperature of the polymer in water, tunable from ca. 25 to above 90 °C. The second block, of trimethyl-2-methacroyloxyethylammonium chloride (TMEC), is positively charged at physiological pH values and is used for DNA binding. The coacervate complexes between the block copolymer and a model single strand DNA are characterized by fluorescence correlation spectroscopy and fluorescence spectroscopy. The new materials offer good prospects for biomedical application, for example in controlled gene delivery.

Drug nanocrystals for cancer therapy

Drug nanocrystals (NCs) with fascinating physicochemical properties have attracted great attention in drug delivery. High drug-loading efficiency, great structural stability, steady dissolution, and long circulation time are a few examples of these properties, which makes drug NCs an excellent formulation for efficient cancer therapy. In the last two decades, there are a lot of hydrophobic or lipophilic drugs, such as paclitaxel (PTX), camptothecin (CPT), thymectacin, busulfan, cyclosporin A, 2-devinyl-2-(1-hexyloxyethyl) pyropheophorbide (HPPH), and so on, which have been formulated into drug NCs for cancer therapy. In this review, we summarized the recent advances in drug NCs-based cancer treatment. So far, there are main three methods to synthesize drug NCs, including top-down, bottom-up, and combination methods. The characterization methods of drug NCs were also elaborated. Furthermore, the applications and mechanisms of drug NCs were introduced by their administration routes. At the end, we gave a brief conclusion and discussed the future perspectives of drug NCs in cancer therapy. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Recent advances in co-delivery systems based on polymeric nanoparticle for cancer treatment

Cancer is a broad term for a class of prevalent diseases as one in three people develop cancer during their lifetime. Although, there are few success stories of cancer therapy, most of the existing medications do not lead to complete recovery. Because of the complexity of cancer, usually a single therapeutic approach is insufficient for the suppression of cancer growth and metastasis. Simultaneous loading and co-delivery of different agents with different physiochemical characteristics to the same tumors have been suggested for minimizing the dose of anticancer drugs and achieving the synergistic therapeutic impacts in cancers treatment. Intense work to develop nanotechnology-based systems as a suitable option for cancer treatment is currently underway. The purpose of this review is to provide an overview of the co-delivery systems based on polymeric nanoparticles including polymeric micelles, dendrimers, poly-d,l-lactide-co-glycolide, polyethylenimine, poly(l-lysine) and chitosan for efficacious cancer therapy.

Postsynthetic Modification of ZIF-90 for Potential Targeted Codelivery of Two Anticancer Drugs

Combination therapy has been regarded as a promising strategy for cancer treatment due to the enhanced anticancer efficacy achieved by blocking multiple drug resistance pathways. In this work, a drug carrier based on nanoscale ZIF-90 for the codelivery of two anticancer drugs has been synthesized by covalently attaching doxorubicin (DOX) to the surface of ZIF-90 via Schiff base reaction of amino group in DOX and aldehyde group of imidazole-2-carboxaldehyde (ICA) ligand and encapsulating 5-fluorouracil (5-FU) into the pores of the framework. The results of drug loading measurements show that the loading amount of drugs was estimated as high as 36.35 and 11-13.5 wt % for 5-FU and DOX, respectively. Moreover, we demonstrated that the carrier had the potential of cancer-targeted delivery of drugs for the collapse of framework under the pH environment around cancer cells and subsequently releasing drugs. Drug release at pH 5.5, imitating the environment of tumor, can reach over 95%, and the release time is less 16 h, meaning a more effective and faster release of drugs around tumoral cells than that in a normal environment. This is the first report for cancer-targeted codelivery of two different chemical drugs based on nanoscale metal-organic frameworks (NMOFs).

Curcumin loading potentiates the chemotherapeutic efficacy of selenium nanoparticles in HCT116 cells and Ehrlich's ascites carcinoma bearing mice

The anticancer properties of selenium (Se) and curcumin nanoparticles in solo formulations as well as in combination with other therapeutic agents have been proved time and again. Exploiting this facet of the two, we clubbed their tumoricidal characteristics and designed curcumin loaded Se nanoparticles (Se-CurNPs) to achieve an enhanced therapeutic effect. We evaluated their therapeutic effects on different cancer cell lines and Ehrlich's ascites carcinoma mouse model. In vitro results showed that Se-CurNPs were most effective on colorectal carcinoma cells (HCT116) compared to the other cancer cell lines used and possessed pleiotropic anticancer effects. The therapeutic effect on HCT116 was primarily attributed to an elevated level of autophagy and apoptosis as evident from significant up-regulation of autophagy associated (LC3B-II) and pro-apoptotic (Bax) proteins, down-regulation of anti-apoptotic (Bcl-2) protein and Cytochrome c (cyt c) release from mitochondria along with reduced NFκB signaling and EMT based machineries marked by downregulation of inflammation (NFκB, phospho-NFκB) and epithelial-mesenchymal transition (CD44, N-cadherin) associated proteins. In vivo studies on Ehrlich's ascites carcinoma (EAC) mice model indicated that Se-CurNPs significantly reduced the tumor load and enhanced the mean survival time (days) of tumor-bearing EAC mice.

Well-defined star polymers for co-delivery of plasmid DNA and imiquimod to dendritic cells

Co-delivery of antigen-encoding plasmid DNA (pDNA) and immune-modulatory molecules has importance in advancing gene-based immunotherapy and vaccines. Here novel star polymer nanocarriers were synthesized for co-delivery of pDNA and imiquimod (IMQ), a poorly soluble small-molecule adjuvant, to dendritic cells. Computational modeling and experimental results revealed that the polymers formed either multimolecular or unimolecular core-shell-type micelles in water, depending on the nature of the outer hydrophilic shell. Micelles loaded with both IMQ and pDNA were able to release IMQ in response to intracellular pH of the endo-lysosome and transfect mouse dendritic cells (DC2.4 line) in vitro. Importantly, IMQ-loaded micelle/pDNA complexes displayed much enhanced transfection efficiency than IMQ-free complexes. These results demonstrate the feasibility of co-delivery of pDNA and IMQ to antigen-presenting cells by multifunctional polymer nanocarriers with potential use in gene-based vaccine approaches.

Insight into the interactions between nanoparticles and cells

This review summarizes the latest advances in nanoparticle (NP)–cell interactions. The influence of NP size, shape, shell structure, surface chemistry and protein corona formation on cellular uptake and cytotoxicity is highlighted in detail. Their impact on other cellular responses such as cell proliferation, differentiation and cellular mechanics is also discussed.

Recent progress in nanomedicine-based combination cancer therapy using a site-specific co-delivery strategy

This review article highlights the recent progresses in nanomedicine-based combination cancer therapy via site-specific co-delivery strategies.

Mustard-inspired delivery shuttle for enhanced blood–brain barrier penetration and effective drug delivery in glioma therapy

A mustard-inspired delivery shuttle was constructed for enhanced blood–brain barrier penetration and effective drug delivery in glioma therapy.

Magnetic solid lipid nanoparticles in hyperthermia against colon cancer

A reproducible double emulsion/solvent evaporation procedure is developed to formulate magnetic solid lipid nanoparticles (average size≈180 nm) made of iron oxide cores embedded within a glyceryl trimyristate solid matrix. The physicochemical characterization of the nanocomposites ascertained the efficacy of the preparation conditions in their production, i.e. surface properties (electrokinetic and thermodynamic data) were almost indistinguishable from those of the solid lipid nanomatrix, while electron microscopy characterizations and X-ray diffraction patterns confirmed the satisfactory coverage of the magnetite nuclei. Hemocompatibility of the particles was established in vitro. Hysteresis cycle determinations defined the appropriate magnetic responsiveness of the nanocomposites, and their heating characteristics were investigated in a high frequency alternating gradient of magnetic field: a constant maximum temperature of 46 °C was obtained within 40 min. Finally, in vitro tests performed on human HT29 colon adenocarcinoma cells demonstrated a promising decrease in cell viability after treatment with the nanocomposites and exposure to that alternating electromagnetic field. To the best of our knowledge, this is the first time that such type of nanoformulation with very promising hyperthermia characteristics has been developed for therapeutic aims.

Smart micro/nanoparticles in stimulus-responsive drug/gene delivery systems

New achievements in the realm of nanoscience and innovative techniques of nanomedicine have moved micro/nanoparticles (MNPs) to the point of becoming actually useful for practical applications in the near future. Various differences between the extracellular and intracellular environments of cancerous and normal cells and the particular characteristics of tumors such as physicochemical properties, neovasculature, elasticity, surface electrical charge, and pH have motivated the design and fabrication of inventive "smart" MNPs for stimulus-responsive controlled drug release. These novel MNPs can be tailored to be responsive to pH variations, redox potential, enzymatic activation, thermal gradients, magnetic fields, light, and ultrasound (US), or can even be responsive to dual or multi-combinations of different stimuli. This unparalleled capability has increased their importance as site-specific controlled drug delivery systems (DDSs) and has encouraged their rapid development in recent years. An in-depth understanding of the underlying mechanisms of these DDS approaches is expected to further contribute to this groundbreaking field of nanomedicine. Smart nanocarriers in the form of MNPs that can be triggered by internal or external stimulus are summarized and discussed in the present review, including pH-sensitive peptides and polymers, redox-responsive micelles and nanogels, thermo- or magnetic-responsive nanoparticles (NPs), mechanical- or electrical-responsive MNPs, light or ultrasound-sensitive particles, and multi-responsive MNPs including dual stimuli-sensitive nanosheets of graphene. This review highlights the recent advances of smart MNPs categorized according to their activation stimulus (physical, chemical, or biological) and looks forward to future pharmaceutical applications.

A Polyethylenimine-Containing and Transferrin-Conjugated Lipid Nanoparticle System for Antisense Oligonucleotide Delivery to AML

Limited success of antisense oligonucleotides (ASO) in clinical anticancer therapy calls for more effective delivery carriers. The goal of this study was to develop a nanoparticle system for delivery of ASO G3139, which targets mRNA of antiapoptotic protein Bcl-2, to acute myeloid leukemia (AML) cells. The synthesized nanoparticle Tf-LPN-G3139 contained a small molecular weight polyethylenimine and two cationic lipids as condensing agents, with transferrin on its surface for selective binding and enhanced cellular uptake. The optimized nitrogen to phosphate (N/P) ratio was 4 to achieve small particle size and high G3139 entrapment efficiency. The Tf-LPN-G3139 exhibited excellent colloidal stability during storage for at least 12 weeks and remained intact for 4 hours in nuclease-containing serum. The cellular uptake results showed extensive internalization of fluorescence-labelled G3139 in MV4-11 cells through Tf-LPN. Following transfection, Tf-LPN-G3139 at 1 µM ASO level induced 54% Bcl-2 downregulation and >20-fold apoptosis compared to no treatment. When evaluated in mice bearing human xenograft AML tumors, Tf-LPN-G3139 suppressed tumor growth by ~60% at the end of treatment period, accompanied by remarkable pharmacological effect of Bcl-2 inhibition in tumor. In conclusion, Tf-LPN-G3139 is a promising nanoparticle system for ASO G3139 delivery to AML and warrants further investigations.

A poly(ascorbyl acrylate)-containing nanoplatform with anticancer activity and the sequential combination therapy with its loaded paclitaxel

The complex nanocarriers combined with the loaded therapeutic agents to achieve synergistic tumor inhibition.

Theranostics for hepatocellular carcinoma with Fe3O4@ZnO nanocomposites

An Fe₃O₄@ZnO/Dox/TfR Ab was designed and synthesized as a theranostic agent for hepatocellular carcinoma, allowing for a targeted drug delivery with concurrent chemoradiotherapy and visual MRI evaluation of the therapeutic effect.

Bioreducible poly(2-ethyl-2-oxazoline)-PLA-PEI-SS triblock copolymer micelles for co-delivery of DNA minicircles and Doxorubicin

The co-delivery of minicircle DNA (mcDNA) and small anti-cancer drugs via stimuli-sensitive nanocarriers is a promising approach for combinatorial cancer therapy. However, the simultaneous loading of drugs and DNA in nanosized delivery systems is remarkably challenging. In this study we describe the synthesis of triblock copolymer micelles based on poly(2-ethyl-2-oxazoline)-poly(L-lactide) grafted with bioreducible polyethylenimine (PEOz-PLA-g-PEI-SS) for co-delivery of supercoiled (sc) mcDNA vectors and Doxorubicin (Dox). These amphiphilic carriers take advantage of non-fouling oxazolines to confer biological stability, of PLA to provide a hydrophobic core for drug encapsulation and of bioreducible PEI-SS to provide mcDNA complexation and an on-demand stimuli-responsive release. The obtained results show that mcDNA-loaded micelleplexes penetrate into in vitro tumor spheroid models with specific kinetics and exhibit a higher gene expression when compared to non-bioreducible nanocarriers. Moreover, in vivo bioluminescence imaging showed that gene expression is detected up to 8days following mcDNA-micelles intratumoral administration. Furthermore, drug-gene co-delivery in PEOz-PLA-g-PEI-SS carriers was verified by successful encapsulation of both Dox and mcDNA with high efficacy. Moreover, dual-loaded micelleplexes presented significant uptake and a cytotoxic effect in 2D cultures of cancer cells. The co-delivery of mcDNA-Dox to B16F10-Luciferase tumor bearing mice resulted in a reduction in tumor volume and cancer cells viability. Overall, such findings indicate that bioreducible triblock micelles are efficient for focal delivery in vivo and have potential for future application in combinatorial DNA-drug therapy.

Ultrasound-Triggered Phase-Transition Cationic Nanodroplets for Enhanced Gene Delivery

Ultrasound as an external stimulus for enhanced gene transfection represents a safe, noninvasive, cost-effective delivery strategy for gene therapy. Herein, we have developed an ultrasound-triggered phase-transition cationic nanodroplet based on a novel perfluorinated amphiphilic poly(amino acid), which could simultaneously load perfluoropentane (PFP) and nucleic acids. The heptadecafluoroundecylamine (C11F17-NH2) was chosen to initiate β-benzyl-L-aspartate N-carboxyanhydride (BLA-NCA) ring-opening polymerization to prepare C11F17-poly(β-benzyl-L-aspartate) (C11F17-PBLA). Subsequently, C11F17-poly{N-[N'-(2-aminoethyl)]aspartamide} [C11F17-PAsp(DET)] was synthesized by aminolysis reaction of C11F17-PBLA with diethylenetriamine (DET). PFP/pDNA-loaded nanodroplets PFP-TNDs [PFP/C11F17-PAsp(DET)/LucDNA/γ-PGA or poly(glutamic acid)-g-MeO-poly(ethylene glycol) (PGA-g-mPEG) ternary nanodroplets] were primarily formulated by an oil/water emulsification method, followed by surface modification with PGA-g-mPEG. The average diameter of PFP-TNDs ranged from 300 to 400 nm, and transmission electron microscopy images showed that the nanodroplets were nearly spherical in shape. The ζ potential of the nanodroplets dramatically decreased from +54.3 to +15.3 mV after modification with PGA-g-mPEG, resulting in a significant increase of the stability of the nanodroplets in the serum-containing condition. With ultrasound irradiation, the gene transfection efficiency was enhanced 14-fold on HepG2 cells, and ultrasound-triggered phase-transition cationic nanodroplets also displayed a good ultrasound contrast effect. These results suggest that the PFP/DNA-loaded phase-transition cationic nanodroplets can be utilized as efficient theranostic agents for targeting gene delivery.