Hyaluronic acid-shelled acid-activatable paclitaxel prodrug micelles effectively target and treat CD44-overexpressing human breast tumor xenografts in vivo

Recent Advances in Targeted Tumor Chemotherapy Based on Smart Nanomedicines

Efficacy and safety of chemotherapeutic drugs constitute two major criteria in tumor chemotherapy. Nanomedicines with tumor-targeted properties hold great promise for improving the efficacy and safety. To design targeted nanomedicines, the pathological characteristics of tumors are extensively and deeply excavated. Here, the rationale, principles, and advantages of exploiting these pathological characteristics to develop targeted nanoplatforms for tumor chemotherapy are discussed. Homotypic targeting with the ability of self-recognition to source tumors is reviewed individually. In the meanwhile, the limitations and perspective of these targeted nanomedicines are also discussed.

Small-Sized Cationic miRi-PCNPs Selectively Target the Kidneys for High-Efficiency Antifibrosis Treatment

Small-sized cationic miRi (microRNA-21 inhibitor)-PCNPs (low molecular weight chitosan (LMWC)-modified polylactide-co-glycoside (PLGA) nanoparticles (PLNPs)) with special kidney-targeting and high-efficiency antifibrosis treatment are fabricated through coupling miRi, PLGA, and LMWC. In the miRi-PCNPs, easily degraded miRi is encapsulated in PCNPs and thus prevented from degradation by nuclease. Cytotoxicity, immunotoxicity, and systemic toxicity assays and in vitro and ex vivo fluorescence imaging suggest that PCNPs possess excellent biocompatibility, higher cellular uptake efficiency, and selective kidney-targeting capacity. Western blotting, pathological staining, and real-time polymerase chain reaction analyses show that the therapeutic effect of miRi-PCNPs on kidney fibrosis is much higher than that of miRi, which is mainly through suppressing transforming growth factor beta-1/drosophila mothers against decapentaplegic protein 3 (TGF-β1/Smad3) and extracellular signal-regulated kinases/mitogen-activated protein kinase signaling pathway by inhibiting the expression of microRNA-21. For example, the tubule damage index and tubulointerstitial fibrosis area in the miRi-PCNPs group are ≈2.5-fold lower than those in the saline and bare miRi groups. The miRi-PCNPs with special kidney-targeting and high-efficiency antifibrosis treatment may represent a promising strategy for designing and developing a therapeutic treatment for kidney fibrosis.

Anisotropic Gold Nanoparticles in Biomedical Applications

Gold nanoparticles (AuNPs) play a crucial role in the development of nanomedicine, principally due to their unique photophysical properties and high biocompatibility. The possibility to tune and customize the localized surface plasmon resonance (LSPR) toward near-infrared region by modulating the AuNP shape is one of the reasons for the huge widespread use of AuNPs. The controlled synthesis of no-symmetrical nanoparticles, named anisotropic, is an exciting goal achieved by the scientific community which explains the exponential increase of the number of publications related to the synthesis and use of such type of AuNPs. Even with such steps forward and the AuNP translation in clinic being done, some key issues are still remain and they are related to a reliable and scalable production, a full characterization, and to the development of nanotoxicology studies on the long run. In this review we highlight the very recent advances on the synthesis of the main classes of anisotropic AuNPs (nanorods, nanourchins and nanocages) and their use in the biomedical fields, in terms of diagnosis and therapeutics.

Gastric cancer combination therapy: synthesis of a hyaluronic acid and cisplatin containing lipid prodrug coloaded with sorafenib in a nanoparticulate system to exhibit enhanced anticancer efficacy and reduced toxicity

Purpose

Gastric cancer is one of the most common human epithelial malignancies, and using nanoparticles (NPs) in the diagnosis and treatment of cancer has been extensively studied. The aim of this study was to develop hyaluronic acid (HA) containing lipid NPs coloaded with cisplatin (CDDP) and sorafenib (SRF) for the treatment of gastric cancer.

Materials and methods

HA and CDDP containing lipid prodrug was synthesized using polyethylene glycol (PEG) as a linker (HA-PEG-CDDP). HA-PEG-CDDP and SRF were entrapped into the lipid NPs by nanoprecipitation method (H-CS-NPs). The physicochemical and biochemical properties such as size, zeta potential, and drug release pattern were studied. In vitro viability was also evaluated with MKN28 and SGC7901 human gastric cancer cells. In vivo testing including biodistribution and accumulation in tumor tissue was applied in gastric tumor-bearing mice to confirm the inhibition of gastric cancer.

Results

H-CS-NP has a particle size of 173.2±5.9 nm, with a zeta potential of −21.5±3.2 mV. At day 21 of in vivo treatment, H-CS-NPs inhibited the tumor volume from 1,532.5±41.3 mm³ to 259.6±16.3 mm³ with no obvious body weight loss. In contrast, mice treated with free drugs had body weight loss from 20 to 15 g at the end of study.

Conclusion

The results indicate that H-CS-NPs enhanced the antitumor effect of drugs and reduced the systemic toxicity effects. It could be used as a promising nanomedicine for gastric cancer combination therapy.

Bioresponsive albumin-conjugated paclitaxel prodrugs for cancer therapy

The efficacy of traditional chemotherapy often suffers from rapid clearance and off-target toxicity. Drug delivery systems and controlled release are applied to improve the therapeutic efficiencies of small-molecule drugs. In this work, two novel oxidative/reductive (Ox/Re) -sensitive and one non-sensitive Paclitaxel (PTX) prodrugs were synthesized with a maleimide group, which rapidly conjugates with albumin in vivo. Albumin serves as a good vehicle to deliver more prodrug to tumors due to the enhanced permeation and retention (EPR) effect. PTX was then released from the prodrugs in glutathione(GSH)/ reactive oxygen species(ROS)-rich tumor microenvironments. This bioresponsive prodrug strategy demonstrates potent chemotherapeutic efficiency in vivo and may be utilized in clinical cancer therapy.

Smart nanocarrier based on PEGylated hyaluronic acid for deacetyl mycoepoxydience: High stability with enhanced bioavailability and efficiency

Deacetyl mycoepoxydience (DM) nanocrystals core were stabilized by the folate modified distearoylphosphatidyl ethanolamine-polyethylene glycol (DSPE-PEG₂₀₀₀-FA) as the active-targeting stabilizer and D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) as the reversion of multidrug resistance stabilizer, respectively. The DM nanocrystals was acted as the core and shelled by the polyethylene glycol-hyaluronic acid (PEG-HA). The optimal core-shell system demonstrated superior stability at 4 °C for 6 weeks by the stability study and higher dissolution velocity. Cytotoxicity in vitro and cell proliferation inhibition was evaluated by MCF-7 cells line. Furthermore, the core-shell nanocrystals revealed a concentration- and time-dependent cytotoxicity activity and enhanced the cell proliferation inhibition. Pharmacokinetic studies in rabbits showed core-shelled DM nanocrystals significantly increased AUC and t_1/2 and reduced CL_z compared to the DM solution for intravenous delivery. Results indicated that core-shell nanocrystals nanogel was successfully established with higher stability and the bioavailability of DM with higher safety was improved.

Sequentially self-assembled polysaccharide-based nanocomplexes for combined chemotherapy and photodynamic therapy of breast cancer

Combination of chemotherapy and photodynamic therapy has emerged as a promising anticancer strategy. Polysaccharide-based nanoparticles are being intensively explored as drug carriers for different forms of combination therapy. In this study, novel multifunctional polysaccharide-based nanocomplexes were prepared from aldehyde-functionalized hyaluronic acid and hydroxyethyl chitosan via sequential self-assembly method. Stable nanocomplexes were obtained through both Schiff's base bond and electrostatic interactions. Chemotherapeutics doxorubicin and pro-photosensitizer 5-aminolevulinic acid were chemically conjugated onto the nanocomplexes via Schiff base linkage. Anti-HER2 antibody as targeting moiety was decorated onto the surface of nanocomplexes. The obtained near-spherical shaped nanocomplexes had an average size of 140 nm and a zeta potential of -24.6 mV, and displayed pH-responsive surface charge reversal and drug release. Active targeting strategy significantly enhanced the cellular uptake of nanocomplexes and combined anticancer efficiency of chemo-photodynamic dual therapy in breast cancer MCF-7 cells. These results suggested that the nanocomplexes had great potential for targeted combination therapy of breast cancer.

pH-Responsive hyaluronated liposomes for docetaxel delivery

In this study, we report pH-responsive liposomes consisting of hydrogenated soy phosphatidylcholine (HSPC) as a lipid, hyaluronic acid (HA) grafted with functional 3-diethylaminopropyl (DEAP) groups (hereafter denoted as HA-g-DEAP) as a pH-responsive polymer, and docetaxel (DTX) as an antitumor drug. DTX-loaded HSPC liposomes were prepared via a conventional liposome manufacturing procedure and then were decorated with HA-g-DEAP (HA-g-DEAP0.15, HA-g-DEAP0.25, and HA-g-DEAP0.40, according to the molar conjugate ratio of DEAP to HA) in an aqueous solution (pH 7.4), by sonication. The liposomes with HA-g-DEAP0.40 allowed the efficient release of the encapsulated DTX content when the pH of the solution decreased to 6.5 (i.e., endosomal pH), owing to the acidic pH-induced protonation of the DEAP anchored to the vesicular lipid bilayers. These hyaluronated liposomes were effective at entering the human colon carcinoma HCT-116 cells with a CD44 receptor overexpression. In an in vitro tumor cell cytotoxicity test, the DTX-loaded liposomes caused a significant increase in HCT-116 tumor cell death, revealing their pharmaceutical potential in tumor therapy.

LAPONITE® nanoplatform functionalized with histidine modified oligomeric hyaluronic acid as an effective vehicle for the anticancer drug methotrexate

The synthetic clay material, LAPONITE® (LAP), having a nanodisk structure together with a negatively charged surface, has been used for effective drug encapsulation by virtue of its interlayer space. In this research effort, the LAP nanodisk was used for the first time to encapsulate the antifolic methotrexate (MTX); the MTX-loaded LAP nanodisks (LAP/MTX) demonstrated a high drug loading efficiency of 80.39%. An efficient and reliable tumor-targeting device that rests on the synthesized oligomeric hyaluronic acid-l-histidine (oHA-His) was then encapsulated in the MTX-loaded LAP disks (forming LAP/MTX/oHA-His nanohybrids). The drug released from the LAP/MTX/oHA-His nanohybrids was pH-dependent and matched the first-order kinetics that describes the diffusion mechanism. In vitro biological evaluation manifested that the MTX-loaded LAP nanocarriers, particularly the LAP/MTX/oHA-His nanohybrids that have targetability and lysosomal antineoplastic activity, can be effectively internalized by the MCF-7 cell line, and can exhibit a more prominent anticancer cytotoxicity than free MTX. In vivo studies with mice indicated that the LAP/MTX/oHA-His nanohybrids demonstrated much higher antitumor efficiency compared to the LAP/MTX nanohybrids and pure MTX. Taken together, the LAP/oHA-His, CD44 receptor targeting and pH-sensitive multifunctional nanohybrids conferred the MTX with excellent cytocompatibility, dispersion stability, sustained pH-responsive release properties, and improved anticancer activity, and may be further developed as a potential active nanoplatform for various anticancer drugs.

Development of a novel morphological paclitaxel-loaded PLGA microspheres for effective cancer therapy: in vitro and in vivo evaluations

Sustained release of therapeutic agents into tumor cells is a potential approach to improve therapeutic efficacy, decrease side effects, and the drug administration frequency. Herein, we used the modified double-emulsion solvent evaporation (DSE) method to prepare a novel morphological paclitaxel (PTX) loaded poly(lactide-co-glycolide) (PLGA) microspheres (MS). The prepared rough PTX-PLGA-MS possessed microporous surface and highly porous internal structures, which significantly influenced the drug entrapment and release behaviors. The rough MS with an average particle size of 53.47 ± 2.87 μm achieved high drug loading (15.63%) and encapsulation efficiency (92.82%), and provided a favorable sustained drug release. The in vitro antitumor tests of flow cytometry and fluoroimmunoassay revealed that the rough PTX-PLGA-MS displayed effective anti-gliomas activity and enhanced the cellular PTX uptake through adsorptive endocytosis. Both in vitro and in vivo antitumor results demonstrated that the sustained-release PTX could induce the microtubules assembly and the over-expression of Bax and Cyclin B1 proteins, resulting in the microtubule dynamics disruption, G2/M phase arrest, and cell apoptosis accordingly. Furthermore, as the rough PTX-PLGA-MS could disperse and adhere throughout the tumor sites and cause extensive tumor cell apoptosis with one therapeutic course (12 days), they could reduce the system toxicity and drug administration frequency, thus achieving significant tumor inhibitory effects with rapid sustained drug release. In conclusion, our results verified that the rough PTX-PLGA-MS drug release system could serve as a promising treatment to malignant glioma.

One-Pot Synthesis of pH/Redox Responsive Polymeric Prodrug and Fabrication of Shell Cross-Linked Prodrug Micelles for Antitumor Drug Transportation

Shell cross-linked (SCL) polymeric prodrug micelles have the advantages of good blood circulation stability and high drug content. Herein, we report on a new kind of pH/redox responsive dynamic covalent SCL micelle, which was fabricated by self-assembly of a multifunctional polymeric prodrug. At first, a macroinitiator PBYP- ss- iBuBr was prepared via ring-opening polymerization (ROP), wherein PBYP represents poly[2-(but-3-yn-1-yloxy)-2-oxo-1,3,2-dioxaphospholane]. Subsequently, PBYP- hyd-DOX- ss-P(DMAEMA- co-FBEMA) prodrug was synthesized by a one-pot method with a combination of atom transfer radical polymerization (ATRP) and a Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction using a doxorubicin (DOX) derivative containing an azide group to react with the alkynyl group of the side chain in the PBYP block, while DMAEMA and FBEMA are the abbriviations of N, N-(2-dimethylamino)ethyl methacrylate and 2-(4-formylbenzoyloxy)ethyl methacrylate, respectively. The chemical structures of the polymer precursors and the prodrugs have been fully characterized. The SCL prodrug micelles were obtained by self-assembly of the prodrug and adding cross-linker dithiol bis(propanoic dihydrazide) (DTP). Compared with the shell un-cross-linked prodrug micelles, the SCL prodrug micelles can enhance the stability and prevent the drug from leaking in the body during blood circulation. The average size and morphology of the SCL prodrug micelles were measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The SCL micelles can be dissociated under a moderately acidic and/or reductive microenvironment, that is, endosomal/lysosomal pH medium or high GSH level in the tumorous cytosol. The results of DOX release also confirmed that the SCL prodrug micelles possessed pH/reduction responsive properties. Cytotoxicity and cellular uptake analyses further revealed that the SCL prodrug micelles could be rapidly internalized into tumor cells through endocytosis and efficiently release DOX into the HeLa and HepG2 cells, which could efficiently inhibit the cell proliferation. This study provides a fast and precise synthesis method for preparing multifunctional polymer prodrugs, which hold great potential for optimal antitumor therapy.

Reduction-sensitive CD44 receptor-targeted hyaluronic acid derivative micelles for doxorubicin delivery

Introduction

A reduction-sensitive CD44-positive tumor-targetable drug delivery system for doxorubicin (DOX) delivery was developed based on hyaluronic acid (HA)-grafted polymers.

Materials and methods

HA was conjugated with folic acid (FA) via a reduction-sensitive disulfide linkage to form an amphiphilic polymer (HA-ss-FA). The chemical structure of HA-ss-FA was analyzed by ultraviolet spectroscopy, Fourier transform infrared spectroscopy, and ¹H nuclear magnetic resonance (NMR) spectroscopy. The molecular weight of HA-ss-FA was determined by high-performance gel permeation chromatography. Blank HA-ss-FA micelles and DOX-loaded micelles were prepared and characterized. The reduction responsibility, cellular uptake, and in vivo biodistribution of HA-ss-FA micelles were investigated.

Results

DOX-loaded micelles were of high encapsulation efficiency (88.09%), high drug-loading content (22.70%), appropriate mean diameter (100-120 nm), narrow size distribution, and negative zeta potential (-6.7 to -31.5 mV). The DOX release from the micelles was significantly enhanced in reduction environment compared to normal environment. The result of in vitro cytotoxicity assay indicated that the blank micelles were of low toxicity and good biocompatibility and the cell viabilities were >100% with the concentration of HA-ss-FA from 18.75 to 600.00 μg/mL. Cellular uptake and in vivo biodistribution studies showed that DOX-loaded micelles were tumor-targetable and could significantly enhance cellular uptake by CD44 receptor-mediated endocytosis, and the cellular uptake of DOX in CD44-positve A549 cells was 1.6-fold more than that in CD44-negative L02 cells. In vivo biodistribution of HA-ss-FA micelles showed that micelles were of good in vivo tumor targetability and the fluorescence of indocyanine green (ICG)-loaded micelles was 4- to 6.6-fold stronger than free ICG within 6 h in HCCLM3 tumor-bearing nude mice.

Conclusion

HA-ss-FA is a promising nanocarrier with excellent biocompatibility, tumor targetability, and controlled drug release capability for delivery of chemotherapy drugs in cancer therapy.

Hyaluronic acid functionalized green reduced graphene oxide for targeted cancer photothermal therapy

Reduced graphene oxide (rGO) nanomaterials display promising properties for application in cancer photothermal therapy (PTT). rGO is usually obtained by treating graphene oxide (GO) with hydrazine hydrate. However, this reducing agent contributes for the low cytocompatibility exhibited by rGO. Furthermore, rGO has a low water stability and does not show selectivity towards cancer cells. Herein, rGO attained using an environmentally-friendly method was functionalized with a novel hyaluronic acid (HA)-based amphiphilic polymer to be used in targeted cancer PTT. Initially, the green-reduction of GO with L-Ascorbic acid was optimized considering the near infrared absorption and the size distribution of the nanomaterials. Then, rGO was functionalized with the HA-based amphiphile. The functionalization of rGO improved its stability, cytocompatibility and internalization by CD44 overexpressing cells, which indicates the targeting capacity of this nanoformulation. Furthermore, the on-demand PTT mediated by HA-functionalized rGO induced cancer cells' ablation, thereby confirming its potential for targeted cancer therapy.

A targeted nanoplatform co-delivering chemotherapeutic and antiangiogenic drugs as a tool to reverse multidrug resistance in breast cancer

Several obstacles are currently impeding the successful treatment of breast cancer, namely impaired drug accumulation into the tumor site, toxicity to normal cells and narrow therapeutic index of chemotherapy, multidrug resistance (MDR) and the metastatic spread of cancer cells through the blood and lymphatic vessels. In this regard, we designed a novel multifunctional nano-sized drug delivery system based on LyP-1 peptide-modified low-molecular-weight heparin-quercetin conjugate (PLQ). This nanosystem was developed for targeted co-delivery of multiple anticancer drugs to p32-overexpressing tumor cells and peritumoral lymphatic vessels, using LyP-1 peptide as active targeting ligand, with the aim to achieve a targeted combinatorial chemo/angiostatic therapy and MDR reversal. The cellular uptake of PLQ nanoparticles by p32-overexpressing breast cancer cells was significantly higher than nonfunctionalized nanoparticles. Besides, the anti-angiogenic activity of PLQ nanoparticles was proven by the effective inhibition of the bFGF-induced neovascularization in subcutaneous Matrigel plugs. More importantly, PLQ/GA nanoparticles with better targeting ability toward p32-positive tumors, displayed a high antitumor outcome by inhibition of tumor cells proliferation and angiogenesis. Immunohistochemistry and western blot assay showed that PLQ/GA nanoparticles significantly disrupted the lymphatic formation of tumor, and inhibited the P-glycoprotein (P-gp) expression in MCF-7 tumor cells, respectively. In conclusion, PLQ/GA nanoparticles provide a synergistic strategy for effective targeted co-delivery of chemotherapeutic and antiangiogenic agents and reversing MDR and metastasis in breast cancer.

STATEMENT OF SIGNIFICANCE

Herein, we successfully developed a novel amphiphilic nanomaterial, LyP-1-LMWH-Qu (PLQ) conjugate, consisting of a tumor-targeting moiety LyP-1, a hydrophobic quercetin (a multidrug resistance [MDR]-reversing drug) inner core, and a hydrophilic low-molecular-weight heparin (an antiangiogenic agent) outer shell for encapsulating and delivering a hydrophobic chemotherapeutic agent (gambogic acid). This versatile nanoplatform with multiple targeted features, i.e., dual chemo/angiostatic effects, destruction ability of the peritumoral lymphatic vessels, and reversal of MDR, resulted in a significantly stronger antitumor efficacy and lower toxic side effect than those of nontargeted nanoparticles and the free drug solution. Therefore, this versatile nanosystem might provide a novel insight for the treatment and palliation of breast cancer by targeted co-delivery of chemo/antiangiogenic agents and reversing MDR and metastasis.

Polysaccharide-modified nanoparticles with intelligent CD44 receptor targeting ability for gene delivery

BACKGROUND

Hyaluronic acid (HA) and chondroitin sulfate (CD) are endogenous polysaccharides. In recent years, they have aroused the interest of scientists because of specific binding to CD44 receptors, which are overexpressed in several types of tumors.

METHODS

In this study, HA- and CD-modified poly(D,L-lactide-co-glycolide)-poly(ethylene glycol) (PLGA-PEG) copolymers were synthesized and applied to encapsulate 1,2-Dioleoyl-3-trimethylammonium-propane (DOTAP)/pDNA (D/P) lipoplex as CD44 receptor targeting gene delivery nanoparticles (NPs).

RESULTS

The particle size of CD-PEG-PLGA-D/P (186.8 ± 21.7 nm) was smaller than that of HA-PEG-PLGA-D/P (270.2 ± 13.8 nm), with narrow size distribution, and both HA-PEG-PLGA-D/P NPs and CD-PEG-PLGA NPs possessed negative zeta potentials (-39.63 ± 5.44 mV and -38.9 ± 2.0 mV, respectively), which prevent erythrocytes from agglutination. Both NPs exhibited pH-dependent release and had faster release in pH 4.0 than in pH 7.4. Generally, the CD-PEG-PLGA-D/P NPs possessed less cytotoxicity than HA-PEG-PLGA-D/P NPs. The D/P-loaded HA-PEG-PLGA and CD-PEG-PLGA NPs expressed significantly higher transfection in CD44 high-expressed U87 (30.1% ± 2.1% and 40.7% ± 4.3%, respectively) than in CD44-negative HepG2 (3.3% ± 1.5% and 1.4% ± 1.0%, respectively) (p < 0.001). It was revealed that the endocytosis of HA-PEG-PLGA-D/P NPs was majorly dominated by macropinocytosis and the endocytosis of CD-PEG-PLGA-D/P NPs was dominated by clathrin-mediated endocytosis pathway (p < 0.001).

CONCLUSION

The high selectivity to CD44-positive U87 cancer cells and low cytotoxicity in L929 normal cells assured the promising potential of CD-PEG-PLGA NPs as gene delivery nano-carriers.

Tumor-targeted and nitric oxide-generated nanogels of keratin and hyaluronan for enhanced cancer therapy

The development of safe and effective nano-drug delivery systems to deliver anticancer drugs to targeted cells and organs is crucial to enhance the therapeutic efficacy and overcome unwanted side effects of chemotherapy. Herein, we prepared CD44-targeted dual-stimuli responsive human hair keratin and hyaluronic acid nanogels (KHA-NGs) through a simple crosslinking method. KHA-NGs, which consisted of spheres 50 nm in diameter, were used as carriers to load the anticancer drug doxorubicin hydrochloride (DOX). The drug release, cellular uptake, cytotoxicity, and targeting ability of DOX-loaded KHA-NGs (DOX@KHA-NGs) were assessed in vitro and the anticancer effects were further evaluated in vivo. The DOX@KHA-NGs had a super-high drug loading capacity (54.1%, w/w) and were stable under physiological conditions (10 μM glutathione (GSH)), with the drug being rapidly released under a tumor cell microenvironment of trypsin and 10 mM GSH. Cellular uptake and in vitro cytotoxicity results indicated that DOX@KHA-NGs specifically targeted cancer cells and effectively inhibited their growth. Furthermore, KHA-NGs were capable of improving intracellular nitric oxide levels, which sensitizes the cells and enhances the anticancer efficacy of chemotherapeutic drugs. In vivo experiments showed that DOX@KHA-NGs had a better anti-tumor effect and lower side effects compared to free DOX. These results suggest that the bio-responsive KHA-NGs have potential applications for targeted cancer therapy.

Drug Delivery Systems from Self-Assembly of Dendron-Polymer Conjugates †

This review highlights the utilization of dendron-polymer conjugates as building blocks for the fabrication of nanosized drug delivery vehicles. The examples given provide an overview of the evolution of these delivery platforms, from simple micellar containers to smart stimuli- responsive drug delivery systems through their design at the macromolecular level. Variations in chemical composition and connectivity of the dendritic and polymeric segments provide a variety of self-assembled micellar nanostructures that embody desirable attributes of viable drug delivery systems.

HAase-sensitive dual-targeting irinotecan liposomes enhance the therapeutic efficacy of lung cancer in animals

Among all cancers, lung cancer is one of the most common and serious types of cancer. It is challenging for site-specific delivery of anticancer therapeutics to tumor cells. Herein, we developed a novel“smart” dual-targeting liposomal platform to respond to the highly expressed hyaluronidase (HAase) in the tumor microenvironment and improve tumor targeting and antitumor efficacy.

Methods: In our design, the HA was used as a sensitive linker between a liposomal lipid and long chain PEG block to synthesize three functional conjugates in order to prepare“smart” liposomal platform modified with epidermal growth factor receptor (EGFR) antibody (GE11) and cell-penetrating peptide (TATp). Using irinotecan as a model therapeutic, evaluations were performed on the human lung adenocarcinoma A549 cells as well as the xenografted A549 cancer cells in nude mice.

Results: The GE11/HA/TATp-irinotecan liposomes evidently increased the uptake of irinotecan and showed significant antitumor efficacy in the xenografted A549 cancer cells in nude mice by intravenous administration. The mechanisms were defined to be two aspects: GE11 exhibits high affinity for EGFR binding and the degradation of the HA by HAase results in the long-chain PEG removal and exposure of the previously hidden surface-attached TATp to enhance the target cell internalization.

Conclusion: Our findings suggest that this functional liposomal platform may provide a novel strategy for treating lung cancers because of effective intracellular delivery.

Self-assembled dual fluorescence nanoparticles for CD44-targeted delivery of anti-miR-27a in liver cancer theranostics

Despite the vital role miRNA-27a plays in driving the development and progress of liver cancer, miRNA-based inhibition therapy is hampered due to its undesired degradation and off-target effects. Herein, a multifunctional nanoparticle for noninvasive tracking of targeted delivery of anti-miR-27a oligonucleotides against liver cancer was constructed.

Methods: Dual-fluorescent conjugates (QD-HA-PEI) were first fabricated through crosslinking hyaluronic acid (HA), polyethyleneimine (PEI) and near-infrared (NIR) fluorescent quantum dots (QDs) via a facile one-pot approach. Antisense oligonucleotide was then encapsulated by QD-HA-PEI to form anti-miR-27a/QD-HA-PEI via electrostatic interactions. Targeting, biodistribution, bioimaging, in vitro cytotoxicity and in vivo anti-tumor effects were evaluated and the underlying mechanism was studied.

Results: The NIR fluorescence of anti-miR-27a/QD-HA-PEI could be employed to monitor CD44 receptor-targeted cellular uptake and tumor accumulation. Importantly, the intrinsic fluorescence of anti-miR-27a/QD-HA-PEI remained in the “ON” state in extracellular or blood environment, but switched to the “OFF” state in the intracellular environment, indicating pH-responsive oligonucleotide release. Furthermore, anti-miR-27a/QD-HA-PEI exhibited effective and selective anti-cancer effects in vitro and in vivo with fewer side effects via the direct down-regulation of oncogenic transcription factors FOXO1 and PPAR-γ.

Conclusion: Our findings validate the dual-fluorescent nanoparticles as delivery vectors of therapeutic miRNA, capable of simultaneous tumor imaging and tracking of miRNA-based modulation therapy, thereby providing an efficient and safe approach for liver cancer theranostics.

Factors relating to the biodistribution & clearance of nanoparticles & their effects on in vivo application

Nanoparticles have promising biomedical applications for drug delivery, tumor imaging and tumor treatment. Pharmacokinetics are important for the in vivo application of nanoparticles. Biodistribution and clearance are largely defined as the key points of pharmacokinetics to maximize therapeutic efficacy and to minimize side effects. Different engineered nanoparticles have different biodistribution and clearance processes. The interactions of organs with nanoparticles, which are determined by the characteristics of the organs and the biochemical/physical properties of the nanoparticles, are a major factor influencing biodistribution and clearance. In this review, the clearance functions of organs and the properties related to pharmacokinetics, including nanoparticle size, shape, biodegradation and surface modifications are discussed.

CD44 targeting biocompatible and biodegradable hyaluronic acid cross-linked zein nanogels for curcumin delivery to cancer cells: In vitro and in vivo evaluation

In this study, we developed novel hyaluronic acid cross-linked zein nanogels (HA-Zein NGs) to deliver the potential anticancer agent curcumin (CRC), a naturally occurring phytochemical drug in cancer cells. In vitro studies showed that they are highly compatible with the tested cell lines. They showed CD44 specific uptake in CT26 cell line more than by the CD44 receptor pre-inhibited CT26 cells. The CRC encapsulated HA-Zein NGs (HA-Zein-CRC NGs) found to exert a specific toxicity against CT26 sparing healthy normal fibroblast cells in vitro. The apoptotic effects were further confirmed with flow cytometry showing that the HA-Zein-CRC NGs exhibited high anticancer activity against the CT26 cells. The in vivo bio-distribution with a CT26 tumor model showed their high tumor accumulation thereby improved antitumor efficacy with a low dosage of CRC, compared to the previous reports. Thus, the preclinical studies clearly showed that these novel HA-Zein NGs would be highly beneficial in encapsulating hydrophobic drugs with improved pharmacokinetics thereby enhancing the therapeutic outcomes.

Polysaccharide-Based Controlled Release Systems for Therapeutics Delivery and Tissue Engineering: From Bench to Bedside

Polysaccharides or polymeric carbohydrate molecules are long chains of monosaccharides that are linked by glycosidic bonds. The naturally based structural materials are widely applied in biomedical applications. This article covers four different types of polysaccharides (i.e., alginate, chitosan, hyaluronic acid, and dextran) and emphasizes their chemical modification, preparation approaches, preclinical studies, and clinical translations. Different cargo fabrication techniques are also presented in the third section. Recent progresses in preclinical applications are then discussed, including tissue engineering and treatment of diseases in both therapeutic and monitoring aspects. Finally, clinical translational studies with ongoing clinical trials are summarized and reviewed. The promise of new development in nanotechnology and polysaccharide chemistry helps clinical translation of polysaccharide-based drug delivery systems.

Rational Design of an Amphiphilic Chlorambucil Prodrug Realizing Self-Assembled Micelles for Efficient Anticancer Therapy

The application of anticancer drug chlorambucil (CLB) in chemotherapy is severely restricted by its insolubility, lability, and toxic side effects; therefore, it is challenging to realize a highly efficient anticancer therapy of chlorambucil. To solve the above drawbacks encountered by chlorambucil, herein we proposed an amphiphilic chlorambucil prodrug-based self-assembled micelle strategy to realize the highly efficient anticancer therapy of chlorambucil. 1,6-Hexanediamine hydrochloride (HDH) serving as the hydrophilic segment was covalently bound to hydrophobic CLB to prepare an amphiphilic prodrug CLB-HDH which could self-assemble into micelles in aqueous solution. These micelles can passively target tumor tissues via the enhanced permeability and retention (EPR) effect, leading to enhanced cellular internalization. Both the cytotoxicity assay in vitro and anticancer study in vivo confirmed the excellent therapeutic activity of CLB-HDH micelles in comparison with free chlorambucil. Moreover, the hemolysis examination and histological analysis demonstrated the designed CLB-HDH micelles are safe in drug delivery. Therefore, our designed amphiphilic prodrug CLB-HDH micelles bring new opportunity for chlorambucil clinical application to combat cancers.

Mesoporous silica nanoparticles functionalized with hyaluronic acid. Effect of the biopolymer chain length on cell internalization

Mesoporous silica nanoparticles (MSNs) were functionalized with amino groups (MSN-NH₂) and then with hyaluronic acid, a biocompatible biopolymer which can be recognized by CD44 receptors in tumor cells, to obtain a targeting drug delivery system. To this purpose, three hyaluronic acid samples differing for the molecular weight, namely HA_S (8-15 kDa), HA_M (30-50 kDa) and HA_L (90-130 kDa), were used. The MSN-HA_S, MSN-HA_M, and MSN-HA_L materials were characterized through zeta potential and dynamic light scattering measurements at pH = 7.4 and T = 37 °C to simulate physiological conditions. While zeta potential showed an increasing negative value with the increase of the HA chain length, an anomalous value of the hydrodynamic diameter was observed for MSN-HA_L, which was smaller than that of MSN-HA_S and MSN-HA_M samples. The cellular uptake of MSN-HA samples on HeLa cells at 37 °C was studied by optical and electron microscopy. HA chain length affected significantly the cellular uptake that occurred at a higher extent for MSN-NH₂ and MSN-HA_S than for MSN-HA_M and MSN-HA_L samples. Cellular uptake experiments carried out at 4 °C showed that the internalization process was inhibited for MSN-HA samples but not for MSN-NH₂. This suggests the occurrence of two different mechanisms of internalization. For MSN-NH₂ the uptake is mainly driven by the attractive electrostatic interaction with membrane phospholipids, while MSN-HA internalization involves CD44 receptors overexpressed in HeLa cells.

New utilization of Polygonum multiflorum polysaccharide as macromolecular carrier of 5-fluorouracil for controlled release and immunoprotection

WPMP-2 is an acid polysaccharide isolated from Polygonum multiflorum, which demonstrated excellent immunomodulatory activity. In order to reduce immunosuppression of 5-fluorouracil (5-Fu), WPMP-2 was utilized as a macromolecular carrier to conjugate the 5-Fu derivatives 5-fluorouracil-1-acetic acid (5-FUAC) through ester bond. The conjugate showed controlled drug release behaviour in vitro at 37°C in phosphate buffer (pH7.4), and only 5-FUAC was detected in the media. The cytotoxicity test in vitro showed that the conjugate exhibited different cytotoxicity to HepG-2 and HT-29 cells. In addition, immunization study in vivo illustrated that the conjugate displayed immunoprotective effect by mitigating inhibition and damage effects of 5-Fu on secretion of cytokines, proliferation of splenocytes, and phagocytosis of peritoneal macrophages. It was indicated that the conjugation of 5-Fu and WPMP-2 could be a potential double effective drug delivery system.

Bile Acid-Based Drug Delivery Systems for Enhanced Doxorubicin Encapsulation: Comparing Hydrophobic and Ionic Interactions in Drug Loading and Release

Doxorubicin (Dox) is a drug of choice in the design of drug delivery systems directed toward breast cancers, but is often limited by loading and control over its release from polymer micelles. Bile acid-based block copolymers present certain advantages over traditional polymer-based systems for drug delivery purposes, since they can enable a higher drug loading via the formation of a reservoir through their aggregation process. In this study, hydrophobic and electrostatic interactions are compared for their influence on Dox loading inside cholic acid based block copolymers. Poly(allyl glycidyl ether) (PAGE) and poly(ethylene glycol) (PEG) were grafted from the cholic acid (CA) core yielding a star-shaped block copolymer with 4 arms (CA-(PAGE- b-PEG)₄) and then loaded with Dox via a nanoprecipitation technique. A high Dox loading of 14 wt % was achieved via electrostatic as opposed to hydrophobic interactions with or without oleic acid as a cosurfactant. The electrostatic interactions confer a pH responsiveness to the system. 50% of the loaded Dox was released at pH 5 in comparison to 12% at pH 7.4. The nanoparticles with Dox loaded via hydrophobic interactions did not show such a pH responsiveness. The systems with Dox loaded via electrostatic interactions showed the lowest IC₅₀ and highest cellular internalization, indicating the pre-eminence of this interaction in Dox loading. The blank formulations are biocompatible and did not show cytotoxicity up to 0.17 mg/mL. The new functionalized star block copolymers based on cholic acid show great potential as drug delivery carriers.

Suppress orthotopic colon cancer and its metastasis through exact targeting and highly selective drug release by a smart nanomicelle

The treatment of metastatic cancer is a huge challenge at the moment. Highly precise targeting delivery and drug release in tumor have always been our pursuit in cancer therapy, especially to advance cancer with metastasis, for increasing the efficacy and biosafety. We established a smart nanosized micelle, formed by tocopherol succinate (TOS) conjugated hyaluronic acid (HA) using a disulfide bond linker. The micelle (HA-SS-TOS, HSST) can highly specifically bind with CD44 receptor over-expressed tumor, and response selectively to high GSH level in the cells, inducing disulfide bond breakage and the release of the payload (paclitaxel, PTX). To predict the antitumor efficacy of the micelles more clinically, we established an orthotopic colon cancer model with high metastasis rate, which could be visualized by the luciferase bioluminescence. Our data confirmed CD44 high expression in the colon cancer cells. Highly matching between the micellar fluorescence and bioluminescence of cancer cells in intestines demonstrated an exact recognition of our micelles to orthotopic colon tumor and its metastatic cells, attributing to the mediation of CD44 receptors. Furthermore, the fluorescence of the released Nile Red from the micelles was found only in the tumor and its metastatic cells, and almost completely overlapped with the bioluminescence of the cancer cells, indicating a highly selective drug release. Our micelles presented an excellent therapeutic effect against metastatic colon cancer, and induced significantly prolonged survival time for the mice, which might become a promising nanomedicine platform for the future clinical application against advanced cancers with high CD44 receptor expression.

Hyaluronic Acid-Shelled Disulfide-Cross-Linked Nanopolymersomes for Ultrahigh-Efficiency Reactive Encapsulation and CD44-Targeted Delivery of Mertansine Toxin

It was and remains a big challenge for cancer nanomedicines to achieve high and stable drug loading with fast drug release in the target cells. Here, we report on novel hyaluronic acid-shelled disulfide-cross-linked biodegradable polymersomes (HA-XPS) self-assembled from hyaluronic acid-b-poly(trimethylene carbonate-co-dithiolane trimethylene carbonate) diblock copolymer for ultrahigh-efficiency reactive encapsulation and CD44-targeted delivery of mertansine (DM1) toxin, a highly potent warhead for clinically used antibody-drug conjugates. Remarkably, HA-XPS showed quantitative encapsulation of DM1 even with a high drug loading content of 16.7 wt %. DM1-loaded HA-XPS (HA-XPS-DM1) presented a small size of ∼80 nm, low drug leakage under physiological conditions, and fast glutathione-triggered drug release. MTT assays revealed that HA-XPS was noncytotoxic while HA-XPS-DM1 was highly potent to MDA-MB-231 cells with an IC₅₀ comparable to that of free DM1. The in vitro and in vivo inhibition experiments indicated that HA-XPS could actively target MDA-MB-231 cells. Notably, HA-XPS-DM1 while causing little adverse effect could effectively inhibit tumor growth and significantly prolong survival time in MDA-MB-231 human breast tumor-bearing mice. HA-XPS-DM1 provides a novel and unique treatment for CD44-positive cancers.

pH-Sensitive Coiled-Coil Peptide-Cross-Linked Hyaluronic Acid Nanogels: Synthesis and Targeted Intracellular Protein Delivery to CD44 Positive Cancer Cells

The clinical translation of protein drugs that act intracellularly is limited by the absence of safe and efficient intracellular protein delivery vehicles. Here, pH-sensitive coiled-coil peptide-cross-linked hyaluronic acid nanogels (HA-cNGs) were designed and investigated for targeted intracellular protein delivery to CD44 overexpressing MCF-7 breast cancer cells. HA-cNGs were obtained with a small size of 176 nm from an equivalent mixture of hyaluronic acid conjugates with GY(EIAALEK)₃GC (E3) and GY(KIAALKE)₃GC (K3) peptides, respectively, at pH 7.4 by nanoprecipitation. Circular dichroism (CD) proved the formation of coiled-coil structures between E3 and K3 peptides at pH 7.4 while fast uncoiling at pH 5.0. HA-cNGs showed facile loading of cytochrome C (CC) and greatly accelerated CC release under mild acidic conditions (18.4%, 76.8%, and 91.4% protein release in 24 h at pH 7.4, 6.0, and 5.0, respectively). Confocal microscopy and flow cytometry displayed efficient internalization of CC-loaded HA-cNGs and effective endosomal escape of CC in MCF-7 cancer cells. Remarkably, HA-cNGs loaded with saporin, a ribosome inactivating protein, exhibited significantly enhanced apoptotic activity to MCF-7 cells with a low IC₅₀ of 12.2 nM. These coiled-coil peptide-cross-linked hyaluronic acid nanogels have appeared as a simple and multifunctional platform for efficient intracellular protein delivery.

Self-stabilized, hydrophobic or PEGylated paclitaxel polymer prodrug nanoparticles for cancer therapy

Facile derivatization of paclitaxel (Ptx) and subsequent “drug-initiated” synthesis of well-defined Ptx-polymer prodrugs was performed from nitroxide-mediated polymerization or reversible addition–fragmentation chain transfer polymerization.

Hyaluronan-based graft copolymers bearing aggregation-induced emission fluorogens

In order to develop a technology platform based on two natural compounds from biorenewable resources, a short series of hyaluronan (HA) copolymers grafted with propargylated ferulic acid (HA–FA–Pg) were designed and synthesized to show different grafting degree values and their optical properties were characterized in comparison with reference compounds containing the same ferulate fluorophore. Interestingly, these studies revealed that the ferulate fluorophore was quite sensitive to the restriction of intramolecular motion and its introduction into the rigid HA backbone, as in HA–FA–Pg graft copolymers, led to higher photoluminescence quantum yield values than those obtained with the isolated fluorophore. Thus, the propargyl groups of HA–FA–Pg derivatives were exploited in the coupling with oleic acid through a biocompatible nona(ethylene glycol) spacer as an example of the possible applications of this technology platform. The resulting HA–FA–NEG–OA materials showed self-assembling capabilities in aqueous environment. Furthermore, HA–FA–NEG–OA derivatives have been shown to interact with phospholipid bilayers both in liposomes and living cells, retaining their fluorogenic properties and showing a high degree of cytocompatibility and for this reason they were proposed as potential biocompatible self-assembled aggregates forming new materials for biomedical applications.

A new technology platform has been developed with hyaluronan playing the role of the macromolecular carrier and ferulate the central role of natural small molecule fluorogenic clickable linker.

A dual-responsive, hyaluronic acid targeted drug delivery system based on hollow mesoporous silica nanoparticles for cancer therapy

A novel enzyme and redox dual-responsive targeted drug delivery system based on hollow mesoporous silica nanoparticles was developed for cancer therapy.

A sequential enzyme-activated and light-triggered pro-prodrug nanosystem for cancer detection and therapy

A sequential enzyme-activated and light-triggered pro-prodrug has been developed for cancer biomarker detection and on-demand therapy.

Biomacromolecules as carriers in drug delivery and tissue engineering

Natural biomacromolecules have attracted increased attention as carriers in biomedicine in recent years because of their inherent biochemical and biophysical properties including renewability, nontoxicity, biocompatibility, biodegradability, long blood circulation time and targeting ability. Recent advances in our understanding of the biological functions of natural-origin biomacromolecules and the progress in the study of biological drug carriers indicate that such carriers may have advantages over synthetic material-based carriers in terms of half-life, stability, safety and ease of manufacture. In this review, we give a brief introduction to the biochemical properties of the widely used biomacromolecule-based carriers such as albumin, lipoproteins and polysaccharides. Then examples from the clinic and in recent laboratory development are summarized. Finally the current challenges and future prospects of present biological carriers are discussed.

Acetal-Linked Paclitaxel Polymeric Prodrug Based on Functionalized mPEG-PCL Diblock Polymer for pH-Triggered Drug Delivery

The differences in micro-environment between cancer cells and the normal ones offer the possibility to develop stimuli-responsive drug-delivery systems for overcoming the drawbacks in the clinical use of anticancer drugs, such as paclitaxel, doxorubicin, and etc. Hence, we developed a novel endosomal pH-sensitive paclitaxel (PTX) prodrug micelles based on functionalized poly(ethylene glycol)-poly(ε-caprolactone) (mPEG-PCL) diblock polymer with an acid-cleavable acetal (Ace) linkage (mPEG-PCL-Ace-PTX). The mPEG-PCL-Ace-PTX₅ with a high drug content of 23.5 wt % was self-assembled in phosphate buffer (pH 7.4, 10 mM) into nanosized micelles with an average diameter of 68.5 nm. The in vitro release studies demonstrated that mPEG-PCL-Ace-PTX₅ micelles was highly pH-sensitive, in which 16.8%, 32.8%, and 48.2% of parent free PTX was released from mPEG-PCL-Ace-PTX₅ micelles in 48 h at pH 7.4, 6.0, and 5.0, respectively. Thiazolyl Blue Tetrazolium Bromide (MTT) assays suggested that the pH-sensitive PTX prodrug micelles displayed higher therapeutic efficacy against MCF-7 cells compared with free PTX. Therefore, the PTX prodrug micelles with acetal bond may offer a promising strategy for cancer therapy.

pH-triggered surface charge-switchable polymer micelles for the co-delivery of paclitaxel/disulfiram and overcoming multidrug resistance in cancer

Multidrug resistance (MDR) remains a major challenge for providing effective chemotherapy for many cancer patients. To address this issue, we report an intelligent polymer-based drug co-delivery system which could enhance and accelerate cellular uptake and reverse MDR. The nanodrug delivery systems were constructed by encapsulating disulfiram (DSF), a P-glyco-protein (P-gp) inhibitor, into the hydrophobic core of poly(ethylene glycol)-block-poly(l-lysine) (PEG-b-PLL) block copolymer micelles, as well as 2,3-dimethylmaleic anhydride (DMA) and paclitaxel (PTX) were grafted on the side chain of l-lysine simultaneously. The surface charge of the drug-loaded micelles represents as negative in plasma (pH 7.4), which is helpful to prolong the circulation time, and in a weak acid environment of tumor tissue (pH 6.5-6.8) it can be reversed to positive, which is in favor of their entering into the cancer cells. In addition, the carrier could release DSF and PTX successively inside cells. The results of in vitro studies show that, compared to the control group, the DSF and PTX co-loaded micelles with charge reversal exhibits more effective cellular uptake and significantly increased cytotoxicity of PTX to MCF-7/ADR cells which may be due to the inhibitory effect of DSF on the efflux function of P-gp. Accordingly, such a smart pH-sensitive nanosystem, in our opinion, possesses significant potential to achieve combinational drug delivery and overcome drug resistance in cancer therapy.

Nano-delivery system targeting to cancer stem cell cluster of differentiation biomarkers

Cancer stem cells (CSCs) are one of the most important origins of cancer progression and metastasis. CSCs have unique self-renewal properties and diverse cell membrane receptors that induced the resistance to the conventional chemotherapeutic agents. Therefore, the therapeutic removal of CSCs could result in the cancer cure with lack of recurrence and metastasis. In this regard, targeting CSCs in accordance to their specific biomarkers is a talented attitude in cancer therapy. Various CSCs surface biomarkers have been described, which some of them exhibited similarities on different cancer cell types, while the others are cancer specific and have just been reported on one or a few types of cancers. In this review, the importance of CSCs in cancer development and therapeutic response has been stated. Different CSCs cluster of differentiation (CD) biomarkers and their specific function and applications in the treatment of cancers have been discussed, Special attention has been made on targeted nano-delivery systems. In this regard, several examples have been illustrated concerning specific natural and artificial ligands against CSCs CD biomarkers that could be decorated on various nanoparticulated drug delivery systems to enhance therapeutic index of chemotherapeutic agents or anticancer gene therapy. The outlook of CSCs biomarkers discovery and therapeutic/diagnostic applications was discussed.

Paclitaxel and quercetin nanoparticles co-loaded in microspheres to prolong retention time for pulmonary drug delivery

High drug resistance, poor water solubility, short half-life, and low local drug concentration are obstacles for successful delivery of chemotherapeutic drugs for lung cancer. A new method involving the use of nanoparticles (NPs) for pulmonary delivery is proposed. However, use of NPs is limited by the particle size range for pulmonary drug delivery considering that NPs cannot be deposited directly into the lungs. NPs polymerized into microspheres (polymeric microspheres, PMs) will result in suitable particle sizes and retain the advantages of nanodrugs after redispersion when applied in pulmonary delivery. We report the development of novel NPs in the form of PMs loaded with paclitaxel (PTX) and quercetin (QUE) double drugs based on the synthesis of oleic acid-conjugated chitosan (OA-CTS) for pulmonary delivery. This approach is aimed toward prolonging PTX retention time in the presence of QUE and bypassing P-glycoprotein drug efflux pumps. NPs loaded with PTX or QUE were prepared with 11% substitution degree using OA-CTS as the carrier by ionic cross-linking method, which NPs loaded with PTX or QUE were used in the preparation of PMs by spray-drying. The diameters of the PMs ranged from 1 to 5 μm which had uniform size range. Scanning electron microscopy showed that PMs were polymers formed by a large number of NPs and readily redispersed (after redispersion, size of NPs ranged between 250 and 350 nm) in water within 1 h. PMs displayed slow-release characteristics at pH 4.5 and 7.4. The in vivo pharmacokinetic and biodistribution studies suggested that PMs exhibit prolonged circulation time and a markedly high accumulation in the lung. The obtained results indicate that PMs can serve as a promising pulmonary delivery system for combined pharmacotherapy using hydrophobic anticancer drugs.

Targeted inhibition of human hematological cancers in vivo by doxorubicin encapsulated in smart lipoic acid-crosslinked hyaluronic acid nanoparticles

The chemotherapy of hematological cancers is challenged by its poor selectivity that leads to low therapeutic efficacy and pronounced adverse effects. Here, we report that doxorubicin encapsulated in lipoic acid-crosslinked hyaluronic acid nanoparticles (LACHA-DOX) mediate highly efficacious and targeted inhibition of human hematological cancers including LP-1 human multiple myeloma (MM) and AML-2 human acute myeloid leukemia xenografted in nude mice. LACHA-DOX had a size of ca. 183 nm and a DOX loading content of ca. 12.0 wt.%. MTT and flow cytometry assays showed that LACHA-DOX possessed a high targetability and antitumor activity toward CD44 receptor overexpressing LP-1 human MM cells and AML-2 human acute myeloid leukemia cells. The in vivo and ex vivo images revealed that LACHA-DOX achieved a significantly enhanced accumulation in LP-1 and AML-2 tumor xenografts. Notably, LACHA-DOX effectively suppressed LP-1 as well as AML-2 tumor growth and drastically increased mice survival rate as compared to control groups receiving free DOX or PBS. Histological analyses exhibited that LACHA-DOX caused little damage to the major organs like liver and heart. This study provides a proof-of-concept that lipoic acid-crosslinked hyaluronic acid nanoparticulate drugs may offer a more safe and effective treatment modality for CD44 positive hematological malignancies.

Role of Pericellular Matrix in the Regulation of Cancer Stemness

Cancer stem cells (CSC) are a prominent component of the tumor bulk and extensive research has now identified them as the subpopulation responsible for tumor relapse and resistance to anti-cancer treatments. Surrounding the bulk formed of tumor cells, an extracellular matrix contributes to cancer growth; the main component of the tumor micro-environment is hyaluronan, a large disaccharide forming a molecular network surrounding the cells. The hyaluronan-dependent coat can regulate cell division and motility in cancer progression and metastasis. One of the receptors of hyaluronan is CD44, a surface protein frequently used as a CSC marker. Indeed, tumor cells with high levels of CD44 appear to exhibit CSC properties and are characterized by elevated relapse rate. The CD44-hyaluronan-dependent interactions are Janus-faced: on one side, they have been shown to be crucial in both malignancy and resistance to therapy; on the other, they represent a potential value for future therapies, as disturbing the CD44-hyaluronan axis would not only impair the pericellular matrix but also the subpopulation of self-renewing oncogenic cells. Here, we will review the key roles of HA and CD44 in CSC maintenance and propagation and will show that CSC-like spheroids from a rabdhomyosarcoma cell line, namely RD, have a prominent pericellular coat necessary for sphere formation and for elevated migration. Thus, a better understanding of the hyaluronan-CD44 interactions holds the potential for ameliorating current cancer therapies and eradicating CSC.

New developments and clinical transition of hyaluronic acid-based nanotherapeutics for treatment of cancer: reversing multidrug resistance, tumour-specific targetability and improved anticancer efficacy

This review aims to overview and critically analyses recent developments in achieving tumour-specific delivery of anticancer agents, maximizing anticancer efficacy, and mitigating tumour progression and off-target effects. Stemming from critical needs to develop target-specific delivery vehicles in cancer therapy, various hyaluronic acid (HA)-conjugated nanomedicines have been fabricated owing to their biocompatibility, safety, tumour-specific targetability of drugs and genes, and proficient interaction with cluster-determinant-44 (CD44) receptors over-expressed on the surface of tumour cells. HA-based conjugation or surface modulation of anticancer drugs encapsulated nanocarriers have shown promising efficacy against the various types of carcinomas of liver, breast, colorectal, pancreatic, lung, skin, ovarian, cervical, head and neck and gastric. The success of this emerging platform is assessed in achieving the rapid internalization of anticancer payloads into the tumour cells, impeding cancer cells division and proliferation, induction of cancer-specific apoptosis and prevention of metastasis (tumour progression). This review extends detailed insight into the engineering of HA-based nanomedicines, characterization, utilization for the diagnosis or treatment of CD44 over-expressing cancer subtypes and emphasizing the transition of nanomedicines to clinical cancer therapy.

αvβ3 integrin-targeted micellar mertansine prodrug effectively inhibits triple-negative breast cancer in vivo

Antibody-mertansine (DM1) conjugates (AMCs) are among the very few active targeting therapeutics that are approved or clinically investigated for treating various cancers including metastatic breast cancer. However, none of the AMCs are effective for the treatment of triple-negative breast cancers (TNBCs). Here, we show that cRGD-decorated, redox-activatable micellar mertansine prodrug (cRGD-MMP) can effectively target and deliver DM1 to α_vβ₃ integrin overexpressing MDA-MB-231 TNBC xenografts in nude mice, resulting in potent tumor growth inhibition. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays showed that cRGD-MMP had obvious targetability to MDA-MB-231 cells with a low half-maximal inhibitory concentration (IC₅₀) of 0.18 μM, which was close to that of free DM1 and 2.2-fold lower than that of micellar mertansine prodrug (MMP; nontargeting control). The confocal microscopy studies demonstrated that cRGD-MMP mediated a clearly more efficient cellular uptake and intracellular release of doxorubicin (used as a fluorescent anticancer drug model) in MDA-MB-231 cells. Notably, cRGD-MMP loaded with 1,1′-dioctadecyltetramethyl indotricarbocyanine iodide (DiR; a hydrophobic near-infrared dye) was shown to quickly accumulate in the MDA-MB-231 tumor with strong DiR fluorescence from 2 to 24 h post injection. MMP loaded with DiR could also accumulate in the tumor, although significantly less than cRGD-MMP. The biodistribution studies revealed a high DM1 accumulation of 8.1%ID/g in the tumor for cRGD-MMP at 12 h post injection. The therapeutic results demonstrated that cRGD-MMP effectively suppressed MDA-MB-231 tumor growth at 1.6 mg DM1 equiv./kg without causing noticeable side effects, as shown by little body weight loss and histological analysis. This MMP has appeared as a promising platform for potent treatment of TNBCs.