Drug Carrier For Cancer Therapy Research Articles

Porous Inorganic Carriers Based on Silica, Calcium Carbonate and Calcium Phosphate for Controlled/Modulated Drug Delivery: Fresh Outlook and Future Perspectives.

Porous inorganic nanostructured materials are widely used nowadays as drug delivery carriers due to their adventurous features: suitable architecture, large surface area and stability in the biological fluids. Among the different types of inorganic porous materials, silica, calcium carbonate, and calcium phosphate have received significant attention in the last decade. The use of porous inorganic materials as drug carriers for cancer therapy, gene delivery etc. has the potential to improve the life expectancy of the patients affected by the disease. The main goal of this review is to provide general information on the current state of the art of synthesis of the inorganic porous particles based on silica, calcium carbonate and calcium phosphate. Special focus is dedicated to the loading capacity, controllable release of drugs under internal biological stimuli (e.g., pH, redox, enzymes) and external noninvasive stimuli (e.g., light, magnetic field, and ultrasound). Moreover, the diverse compounds to deliver with silica, calcium carbonate and calcium phosphate particles, ranging from the commercial drugs to genetic materials are also discussed.

A Novel PAA Derivative with Enhanced Drug Efficacy in Pancreatic Cancer Cell Lines.

Nanoparticles have been shown to be effective drug carriers in cancer therapy. Pancreatic cancer forms dense tumours which are often resistant to drug molecules. In order to overcome such multidrug resistance, new drug entities, novel delivery systems and combination therapy strategies are being explored. In this paper, we report the design and synthesis of a poly(allylamine)-based amphiphile modified with hydrophobic naphthalimido pendant groups. Bisnaphthalimide compounds have been shown to possess anticancer activity. The potential of this polymer to encapsulate, solubilize and enhance drug (5-fluorouricil and bis-(naphthalimidopropyl)-diaminooctane) cytotoxicity in BxPC-3 cells was evaluated. Our studies showed that the insoluble drugs could be formulated up to 4.3 mg mL−1 and 2.4 mg mL−1 inside the amphiphiles, respectively. Additionally, the novel poly(allylamine)-naphthalimide carrier resulted in an amplification of cytotoxic effect with drug treatment after 24 h, and was capable of reduction of 50% cell population at concentrations as low as 3 μg mL−1.

PH-sensitive amphiphilic triblock copolymers containing ortho ester main-chains as efficient drug delivery platforms

Triblock copolymer PEG-block-poly(ortho ester urethane)-block-PEG (PEG-POEU-PEG) was conveniently prepared via polycondensation reaction between the ortho ester-containing diol and hexamethylene diisocyanate (HDI) at varying reaction time followed by termination with polyethylene glycol monomethyl ether (mPEG). PEG-POEU-PEG could further self-assemble into nano-scaled micelles. Ortho ester degradation in these micelles was significantly accelerated at pH 5.0 due to its pH sensitivity. In vitro drug release profiles showed that only a small amount of the loaded DOX was released in PBS solution at pH 7.4, while DOX could be quickly released at pH 5.0. MTT assay reveals that the micelles were completely nontoxic to cultured cells. Moreover, DOX-loaded micelles exhibited efficient antitumor efficiency against cancer cells. Therefore, the micelles may be potential drug carriers in cancer therapy.

Charge reversible and biodegradable nanocarriers showing dual pH-/reduction-sensitive disintegration for rapid site-specific drug delivery.

Dual pH-/reduction-sensitive biodegradable poly(methacrylic acid-co-N,N-bis(acryloyl)cystamine)/chitosan/dimethylmaleic anhydride-modified chitosan (PMAABACy/CS/CS-DMMA) nanoparticles with PMAABACy cores as carriers and dimethylmaleic anhydride-modified chitosan as charge reversible shells were rationally designed. PMAABACy cores using N,N-Bis(acryloyl)cystamine (BACy) as a crosslinker and methacrylic acid (MAA) as a monomer were fabricated via a mild and facile one-pot distillation-precipitation polymerization. After that, CS and CS-DMMA were alternately adsorbed on the surface of PMAABACy cores through a mild self-assembly. The results from TEM and DLS reveal that the PMAABACy/CS/CS-DMMA nanoparticles with desired size and hydrodynamic diameter. And then the nanoparticles exhibit the excellent drug-loading capacity and encapsulation efficiency toward anti-cancer agent doxorubicin (DOX), whereas be rapidly triggered to realize the GSH-sensitive site-specific release via the destruction of sulfide cross-linked structure in response to the intracellular environment of tumor cells. Furthermore, their surface charges could transfer from negative in neutral or basic medium to positive in acidic medium to enhance cellular uptake. Most importantly, the excellent anticancer activity has been also revealed using confocal laser scanning microscope (CLSM) analysis, namely successfully delivering DOX molecules to the cell nucleus. These experimental results indicate that such the novel dual pH-/reduction-sensitive biodegradable PMAABACy/CS/CS-DMMA with surface charge reversal have great potential as a desired anticancer drug carrier for cancer therapy.

Magnetic Oleosome as a Functional Lipophilic Drug Carrier for Cancer Therapy.

In the present study, we fabricated magnetic oleosomes functionalized with recombinant proteins as a new carrier for oil-based lipophilic drugs for cancer treatment. The bioengineered oleosome is composed of neutral lipids surrounded by a phospholipid monolayer with embedded oleosin fusion proteins. The oleosin was genetically fused to a nanobody of a green fluorescent protein (GFP). A recombinant protein consisting of immunoglobulin-binding protein LG fused to GFP was used to couple the oleosome to an antibody for targeted delivery to breast cancer cells. The lipid core of the oleosome was loaded with magnetic nanoparticles and carmustine as the lipophilic drug. The magnetic oleosome was characterized using transmission electron microscopy and dynamic light scattering. Moreover, the specific delivery of oleosome into the target cancer cell was investigated via confocal microscopy. To examine the cell viability of the delivered oleosome, a conventional 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was carried out. Furthermore, an animal study was conducted to confirm the effect resulting from the delivery of the anticancer drug-loaded oleosomes. Taken together, the fabricated lipophilic drug-loaded magnetic oleosome can be a powerful tool for oil-based drug delivery agent for cancer therapy.

A reduction-sensitive thermo-responsive polymer: Synthesis, characterization, and application in controlled drug release

Herein, a novel kind of reduction and thermal dual-responsive polymer was synthesized by direct condensation polymerization of poly(ethylene glycol) (PEG) and 3,3′-dithiodipropanoic acid (DTPA). The resulting PEG-DTPA copolymers were soluble in water at room temperature and exhibited reversible thermal-responsive behaviors. The cloud point temperatures of PEG-DTPA copolymers were highly tunable dependent on the polymer concentration and the length of PEG segment. Additionally, the PEG-DTPA copolymers exhibited reduction-responsive behavior due to the presence of disulfide linkage groups in the backbone. This reduction-responsive property allowed the PEG-DTPA copolymers to be used in a drug delivery system. Thus, a triblock copolymer composed of mPEG2k and PEG400-DTPA copolymer was synthesized. The obtained copolymers could self-assemble into spherical micelles and exhibited thermal and reduction dual-responsive structure-variations in aqueous media. Furthermore, the hydrophobic Nile Red was effectively encapsulated into the micelles. The micelles maintained excellent reduction-responsive properties and can release drugs by reduction triggering. These results suggested that the PEG-DTPA copolymer may be promising for use as reduction and thermal dual-responsive drug carriers in cancer therapy.

Cellulose-based Nanocarriers as Platforms for Cancer Therapy.

Cellulose is an important environmentally-friendly renewable polymer on the earth. Cellulose has been widely used as feedstocks for the synthesis of biomaterials, biofuels and biochemicals. Recently, cellulose and cellulose derivatives have received intense attention in biomedical applications, such as tissue engineering, scaffold, artificial blood vessel, skin grafts, artificial skin, drug carrier, and chronic skin diseases, many of which are somehow related to cancer therapy. In this mini-review, we focus on the up-to-date development of cellulosebased nanocarriers used for cancer therapy. Various cellulose-based nanocarriers such as bacterial cellulose (BC), cellulose acetate, microcrystalline cellulose, carboxymethyl cellulose, cellulose nanocrystals, cellulose nanofibrills, etc, are reviewed in terms of being used in drug delivery systems for cancer treatment. Different strategies for the synthesis of cellulose-based nanocarriers are summarized. Special attention is paid on the structure and properties of cellulose-based drug carriers for cancer therapy via some representative examples. Finally, the problems and future developments of these promising polymeric nanocarriers are raised and proposed.

Impact of the surface charge of polydiacetylene micelles on their interaction with human innate immune protein C1q and the complement system

Polydiacetylene (pDA) micelles have been demonstrated to be effective drug carriers for cancer therapy in mouse model. However, little is known about their interaction with the human complement system, which constitutes an important part of the innate immune system and can cause severe hypersensitivity reactions. Herein, we investigate the influence of micelle surface charge on the binding of complement protein C1q, the target recognition unit that activates the classical complement pathway and performs a range of other important physiological functions. Besides the classical pathway, we also investigate the surface charge effect on complement activities through the other activation pathways, namely, the MBL-dependent lectin pathway and the alternative pathway. We synthesized three samples of pDA micelles bearing neutral, anionic, and cationic surface charge motifs, respectively. Surface plasmon resonance showed that none of these micelles interacted with C1q. Results from serum complement activation assays indicated that all micelles were inert to complement, except for the anionic pDA micelles, which activated the alternative pathway.

Comparison of Biomimetic Block Copolymer Micelles as Drug Carriers for Cancer Therapy.

Zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) is a promising alternative for poly(ethylene glycol) (PEG) as micelle shell-forming block. Three different PMPC-based polymeric micelles were designed and compared with PEGylated micelles. Cholesterol-conjugated and disulfide-modified poly(D, L-lactide)-SS-poly(2-methacryloyloxyethyl phosphorylcholine) (CPLA-SS-PMPC) micelles, cholesterol-conjugated CPLA-PMPC micelles without disulfides, and PLA-PMPC micelles without cholesterol-conjugation were compared to PLA-PEG micelles. These PMPC-based micelles showed better hydrophilicity and less protein adsorption. In cellular uptake evaluation, PMPC-based micelles exhibited much better cellular uptake than that of the PLA-PEG, which might reflect strong interaction between the biomimetic PMPC surface and the cellular membrane. In addition, although there was no statistical difference in cellular internalization behavior among these three PMPC-based micelles, the anticancer activity of paclitaxel (PTX)-loaded CPLA-SS-PMPC micelles was significantly higher than those of the other two kinds of micelles. This superiority was attributed to the rapid release of the anticancer drug under the redox environment inside cancer cells.

Amino-functionalized mesoporous silica nanoparticles as efficient carriers for anticancer drug delivery.

Amino-functionalized mesoporous silica nanoparticles (MSN-NH2) were synthesized by a post-grafting method and further studied as carriers for doxorubicin hydrochloride (DOX) delivery. The morphology, structure, and property of MSN-NH2 and DOX-loaded MSN-NH2 (DOX@MSN-NH2) were studied using various techniques, such as transmission electron microscopy, Fourier transformed infrared spectroscopy, N2 adsorption-desorption isotherms, and zeta potentials. The drug loading and release profile as well as the invitro cell cytotoxicity were detaily investigated. The results indicated that the loading content of DOX increased with the decrease of MSN-NH2/DOX mass ratio and/or the increase of amino density. DOX@MSN-NH2 exhibited a pH-dependent drug release, drug release increased as the pH value decreased. Compared with MSN-NH2, which were neglectable cytotoxicity against non-small-cell lung cancer (A549) cells, DOX@MSN-NH2 displayed remarkable cytotoxicity toward A549 cells in dose- and time-dependent manners. It was concluded that the as-synthesized MSN-NH2 could be used as promising drug carriers for cancer therapy.

A magnetic polypeptide nanocomposite with pH and near-infrared dual responsiveness for cancer therapy

A magnetic polypeptide nanocomposite with pH and near-infrared (NIR) dual responsiveness was developed as a drug carrier for cancer therapy, which was prepared through the self-assembly of Fe3O4 superparamagnetic nanoparticles, poly(aspartic acid) derivative (mPEG-g-PDAEAIM) and doxorubicin (DOX) in water. Fe3O4 nanoparticles were prepared to provide the superparamagnetic core of nanocomposites for tumor targeting via chemical co-precipitation. The protonable imidazole groups of mPEG-g-PDAEAIM with a pKa of ~7 were accountable for the pH-responsiveness of nanocomposites. The photothermal effect of nanocomposites under the irradiation of NIR laser was induced via the interactions between dopamine groups of mPEG-g-PDAEAIM and Fe3O4 superparamagnetic nanoparticles to trigger the drug release. NMR, FT-IR, TEM, hysteresis loop analysis and MRI were utilized to characterize the materials. The DOX loaded nanocomposites exhibited pH-responsive and NIR dependent on/off switchable release profiles. The nanocomposites without drug loading (Fe3O4@mPEG-g-PDAEAIM) showed excellent biocompatibility while DOX loaded nanocomposites caused MCF-7 cells’ apoptosis due to the photothermal/chemotherapy combination effects. Overall, the pH and near-infrared dual responsive magnetic nanocomposite had a great potential for cancer therapy.

Abstract 3120: Application of a lectin as a drug carrier for glycan-targeting cancer therapy

Abstract Various cancers such as pancreatic ductal adenocarcinoma (PDAC) remain intractable despite recent advances in tumour-targeting antibody drugs. Although the outermost coating of every cell type is predominantly composed of cell-specific glycans, antibody strategies have hit walls of technical difficulties in intentional glycan targeting, and medico-economic burden. Lectins, proteins with glycan-binding potential, could be used as an alternative scaffold; however, the prejudice that all lectins mediate harmful haemagglutination limited its use only in experimental and diagnostic applications. Here, we show the successful in vivo application of a lectin as a drug carrier for cancer therapy. We have employed rBC2LC-N lectin since this has already shown a specific affinity between PDAC cell-surface glycans. When a lectin-drug conjugate (LecD) was developed by fusion with a bacterial exotoxin, the 50% inhibitory concentration (1.04 pg/ml=0.0195 pM) was 1000 times lower than that of conventional immunotoxins (on the order of ng/ml). In addition, we have revealed that rBC2LC-N lectin was safely administrable to mice without haemagglutination. Administration of this LecD in a PDAC mouse model of subcutaneous nodules and peritoneal dissemination, generated prominent therapeutic effects. The utilization of lectins as an in vivo drug-carrier targeting cancer glycan shows realistic potential when paired with advanced lectin engineering technologies, and their applications could be expanded by coupling with small molecule and/or nanoparticle drugs. Citation Format: Tatsuya Oda, Osamu Shimomura, Hiroaki Tateno, Jun Hirabayashi, Masayuki Noguchi, Shigeru Chiba, Makoto Asashima, Nobuhiro Ohkohchi. Application of a lectin as a drug carrier for glycan-targeting cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3120. doi:10.1158/1538-7445.AM2017-3120

In vitro and in vivo anti-tumor efficiency comparison of phosphorylcholine micelles with PEG micelles

Polymer micelles for anticancer drug delivery have shown many advantages. In this study, poly(ε-caprolactone)-b-poly(2-methacryloyloxyethyl phosphorylcholine) (PCL-PMPC) with bio-inspired structure self-assembled into small and uniform micelles as traditional poly(ε-caprolactone)-b-poly(ethylene glycol) (PCL-PEG). The in vitro and in vivo anti-tumor efficiency of PCL-PMPC and PCL-PEG micelles were detailedly evaluated. The both micelles were able to load DOX with high efficiency. PCL-PMPC micelles exhibited faster drug release at pH 5.5 than that of PCL-PEG micelles. Confocal laser scanning microscopy and flow cytometry results showed that PCL-PMPC micelles were more effectively internalized by tumor cells. DOX-loaded PCL-PMPC micelles presented higher cytotoxicity to tumor cells. PCL-PMPC micelles displayed not only longer circulation time in pharmacokinetics investigation, but also higher accumulation at the tumor site in in vivo imaging study in comparison with PCL-PEG micelles. More importantly, in a tumor model DOX-loaded PCL-PMPC micelles showed better therapeutic efficacy than DOX-loaded PCL-PEG micelles along with mild side effects. Therefore, PCL-PMPC micelles are deemed to be promising drug carriers for cancer therapy.

PH triggered re-assembly of nanosphere to nanofiber: The role of peptide conformational change for enhanced cancer therapy

pH-triggered conformational change and subsequent re-assembly of nanostructures provide a new strategy in nanomedicine for controlled drug release and enhanced therapy. Here, we reported the development of a novel pH-responsive nano-assembly as a drug carrier from peptide amphiphile (PA) consisting of mimicking peptide and stearic acid moieties. The mimicking peptide is a basic 17-amino acid peptide derived from antennapedia homeodomain, and undergoes a conformational transition of the secondary structure from β-sheet at pH7.4 to α-helix at pH5.0. Such transition therefore leads to simultaneous evolution of the self-assembled structure of PA from nanosphere to nanofiber, promotes assemblies retention and then release drugs in the cytoplasm of tumor cell. In vitro studies showed that the doxorubicin (Dox)-loaded PA nanoparticle (PA@Dox) could be uptaken efficiently by the cell due to the membrane penetrating capability of the mimicking peptide and subsequently the released Dox further induce apoptosis of murine colon carcinoma CT26 (MCCC) cell. In a mouse xenograft model of MCCC, administration of PA@Dox via lateral tail vein injection could remarkably retard the tumor growth. The overall results suggested that the PA-based nanocarriers adopting the novel strategy of pH-triggered secondary structural change could enhance therapeutic efficacy and be used as a promising platform for potential development of new generation of drug carriers for cancer therapy.

A fully absorbable biomimetic polymeric micelle loaded with cisplatin as drug carrier for cancer therapy.

cis-dichlorodiammineplatinum(II) (CDDP)-loaded polymeric micelles for cancer therapy have been developed to reduce the serious side effects of cisplatin CDDP. Herein, polymeric micelles incorporated with cisplatin are prepared based on the complexation between CDDP and hydrophilic poly (L-glutamic acid)-b-poly (2-methacryloyloxyethyl phosphorylcholine) (PLG-b-PMPC) diblock copolymers. These CDDP-loaded micelles possess an average size of 91 nm with narrow distribution, providing remarkable stability in media containing proteins. The release of CDDP from the micelles is faster at pH 5.0 and pH 6.0 than that at pH 7.4 and in a sustained manner without initial burst release. In addition, there is almost no difference in cellular uptake between these CDDP-loaded micelles and free CDDP. Moreover, in vitro cytotoxicity test shows they possess high efficacy to kill 4T1 cells as compared with free drug. Thus, PLG-b-PMPC copolymer might be a promising carrier for CDDP incorporating in cancer therapy.

PH responsive micelles based on copolymers mPEG-PCL-PDEA: The relationship between composition and properties

Polymeric micelles with pH response are considered as promising drug carriers for cancer therapy. In this study, copolymers methoxy-poly (ethylene glycol)-b-poly (ε-caprolactone)-b-poly (diethylaminoethyl methacrylate) (mPEG-PCL-PDEA) were designed and synthesized to investigate the relationship between number of pH responsive units and micelle properties. The structures of these copolymers were characterized by nuclear magnetic resonance, Fourier transform infrared, gel permeation chromatograph, differential scanning calorimetry and water contact angle. The micelles of the copolymers were obtained, the micelle properties were studied by critical micellization concentration, micelle size, morphology, pH response, cytotoxicity and drug loading/release. Moreover, dissipative particle dynamics (DPD) was used to investigate the structure of the micelles under different pH. The results showed that the micelle properties including pH sensitivity, cytotoxicity and drug loading/releasing performance, were related to PDEA units in copolymers. So, mPEG-PCL-PDEA micelles with suitable composition are promising as drug carriers due to their high pH sensitivity, low cytotoxicity and good drug loading/releasing performance.

Surface functionalization of methotrexate-loaded chitosan nanoparticles with hyaluronic acid/human serum albumin: Comparative characterization and in vitro cytotoxicity

The active tumor targeting ligands, hyaluronic acid (HA) and human serum albumin (HSA), are considered promising targeting moieties of drug carriers for cancer therapy. The chitosan nanoparticles loaded with methotrexate (MTX-CsNPs) were employed as the core for subsequent coating process. HA and HSA coating solutions were used at different concentrations. The effect of different HA Mw (1000, 360, 10kDa) was also investigated. The coated MTX-CsNPs was characterized proving the success of surface functionalization. The antitumor activity of the prepared MTX-CsNPs was evaluated on MCF-7 breast cancer cell lines. Results showed that both 360 and 10kDa HA allowed for successful HA adsorption, while its Mw and concentration determined negative charge density. HSA coating was accompanied by a slight increase in nanoparticles (NPs) size and a final positive surface charge. The in vitro cytotoxicity proved that HA and HSA coated MTX-CsNPs improved the antitumor activity compared to uncoated NPs and free drug.

A Drug‐Self‐Gated Mesoporous Antitumor Nanoplatform Based on pH‐Sensitive Dynamic Covalent Bond

To achieve on‐demand drug release, mesoporous silica nanocarriers as antitumor platforms generally need to be gated with stimuli‐responsive capping agents. Herein, a “smart” mesoporous nanocarrier that is gated by the drug itself through a pH‐sensitive dynamic benzoic–imine covalent bond is demonstrated. The new system, which tactfully bypasses the use of auxiliary capping agents, could also exhibit desirable drug release at tumor tissues/cells and enhanced tumor inhibition. Moreover, a facile dynamic PEGylation via benzoic–imine bond further endows the drug‐self‐gated nanocarrier with tumor extracellular pH‐triggered cell uptake and improves therapeutic efficiency in vivo. In short, the paradigm shift in capping agents here will simplify mesoporous nanomaterials as intelligent drug carriers for cancer therapy. Moreover, the self‐gated strategy in this work also shows general potential for self‐controlled delivery of natural biomolecules, for example, DNA/RNA, peptides, and proteins, due to their intrinsic amino groups.

Cancer drug delivery in the nano era: An overview and perspectives (Review).

Nanomaterials are increasingly used as drug carriers for cancer therapy. Nanomaterials also appeal to researchers in the areas of cancer diagnosis and biomarker discovery. Several antitumor nanodrugs are currently being tested in preclinical and clinical trials and show promise in therapeutic and other settings. We review the development of nanomaterial drug carriers, including liposomes, polymer nanoparticles, dendritic polymers, and nanomicelles, for the diagnosis and treatment of various cancers. The prospects of nanomaterials as drug carriers for future clinical applications are also discussed.

Dual-pH Sensitive Charge-reversal Nanocomplex for Tumor-targeted Drug Delivery with Enhanced Anticancer Activity.

Poly(β-L-malic acid) (PMLA), a natural aliphatic polyester, has been proven to be a promising carrier for anti-cancer drugs. In spite of excellent bio-compatibility, the application of PMLA as the drug carrier for cancer therapy is limited by its low cellular uptake efficiency. The strong negative charge of PMLA impedes its uptake by cancer cells because of the electrostatic repulsion. In this study, a dual pH-sensitive charge-reversal PMLA-based nanocomplex (PMLA-PEI-DOX-TAT@PEG-DMMA) was developed for effective tumor-targeted drug delivery, enhanced cellular uptake, and intracellular drug release. The prepared nanocomplex showed a negative surface charge at the physiological pH, which could protect the nanocomplex from the attack of plasma proteins and recognition by the reticuloendothelial system, so as to prolong its circulation time. While at the tumor extracellular pH 6.8, the DMMA was hydrolyzed, leading to the charge reversal and exposure of the TAT on the polymeric micelles, thus enhancing the cellular internalization. Then, the polymeric micelles underwent dissociation and drug release in response to the acidic pH in the lyso/endosomal compartments of the tumor cell. Both in vitro and in vivo efficacy studies indicated that the nanocomplex significantly inhibited the tumor growth while the treatment showed negligible systemic toxicity, suggesting that the developed dual pH-sensitive PMLA-based nanocomplex would be a promising drug delivery system for tumor-targeted drug delivery with enhanced anticancer activity.