CD44-mediated Endocytosis Research Articles

Preparation, characterisation and in vitro and in vivo evaluation of CD44-targeted chondroitin sulphate-conjugated doxorubicin PLGA nanoparticles

The purpose of this study was to ascertain the effect of chondroitin sulphate-modified doxorubicin (Dox) nanoparticles on enhancing the tumour-targeting effect and tumour growth inhibition effect of doxorubicin both in vitro and in vivo. The chondroitin sulphate-doxorubicin conjugate and its poly(lactic-co-glycolic acid) (PLGA) nanoparticles (CS-Dox-PLGA) were successfully synthesised, and then characterized by Fourier-transform infrared spectroscopy (FTIR), proton magnetic resonance (1HNMR), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), transmission electron microscope (TEM), zeta potential and laser light scattering. Taking advantage of the enhanced permeability and CD44-mediated endocytosis, CS-Dox-PLGA showed excellent capacity for penetrating the peripheral tumour barrier and into the nucleus of tumour cells. The CS-Dox-PLGA cellular uptake was improved and exhibited a significantly higher level of cytotoxicity in U251 cells. After intravenous administration, the CS-Dox-PLGA showed good pharmacokinetic properties and excellent U251-induced tumour inhibition with low cardiac toxicity. Therefore, CS-Dox-PLGA with low cardiac toxicity and good anti-tumour ability might be a better choice for Dox in clinical practice.

Hyaluronic Acid-Decorated Laponite® Nanocomposites for Targeted Anticancer Drug Delivery.

In this study, hyaluronic acid (HA), a natural polysaccharide that can specifically bind to CD44 receptors, was conjugated onto laponite® (LAP) nanodisks for the encapsulation and specific delivery of the anti-cancer drug doxorubicin (DOX) to CD44-overexpressed cancer cells. The prepared LM-HA could encapsulate DOX efficiently and release drug in a continuous manner with pH-responsiveness. In vitro cell viability assay proved that LM-HA had good biocompatibility, and drug-loaded LM-HA/DOX exhibited targeted anti-tumor effects against HeLa cells with CD44 receptors overexpressed. In addition, the flow cytometric detection and confocal laser scanning microscope results confirmed that LM-HA/DOX could be specifically internalized by HeLa cells via CD44-mediated endocytosis. Therefore, the HA-modified LAP nanodisks with high drug loading efficiency, pH-sensitive drug release properties and CD44 targetability might be an efficient nanoplatform for cancer chemotherapy.

Light-activated drug release from a hyaluronic acid targeted nanoconjugate for cancer therapy.

Hyaluronic acid (HA)-based nanocarriers are of great interest in the drug delivery field due to the tumor targetability via CD44-mediated recognition and endocytosis. However, sufficient tumor-specific release of encapsulated cargoes with steady controllability is necessary to optimize their outcome for cancer therapy. In this study, we constructed a light-activated nanocarrier TKHCENPDOX to enable on-demand drug release at the desired site (tumor). Particularly, TKHCENPDOX encapsulating doxorubicin (DOX) was self-assembled from a HA-photosensitizer conjugate (HA-TK-Ce6) containing reactive oxygen species (ROS)-sensitive thioketal (TK) linkers. Following i.v. injection, TKHCENPDOX was accumulated in the MDA-MB-231 breast tumor xenograft more efficiently through preventing drug leakage in the bloodstream and the HA-mediated targeting effect. Upon internalization into tumoral cells, 660 nm laser irradiation generated ROS during a photodynamic (PDT) process to cleave the TK linker next to Ce6, resulting in light-induced TKHCENPDOX dissociation and selective DOX release in the tumor area. Consequently, TKHCENPDOX showed a remarkable therapeutic effect and minimized toxicity in vivo. This strategy might provide new insight for designing cancer-selective nanoplatforms with active targeting and locoregional drug release simultaneously.

Nanoparticulate photosensitizer decorated with hyaluronic acid for photodynamic/photothermal cancer targeting therapy.

A photomedicine consisting of a core for photothermal therapy, a photosensitizer for photodynamic therapy, and a cancer-targeting moiety was fabricated to improve photosensitizer selectivity and antitumor efficiency. Hyaluronic acid-decorated polydopamine nanoparticles with conjugated chlorin e6 (HA-PDA-Ce6) were synthesized and characterized. Cell uptake, phototoxicity, penetration, distribution and therapeutic effects were evaluated. HA-PDA-Ce6 had high photoactivities for photodynamic therapy/photothermal therapy and was readily internalized via CD44-mediated endocytosis. Enhanced accumulation and deeper penetration into tumors were achieved by the diffusion molecular retention tumor targeting effect following peritumoral injection. In the combination therapy, HA-PDA-Ce6 displayed the highest tumor growth inhibition in HCT-116 tumor-bearing mice. HA-PDA-Ce6 is promising for targeted colorectal cancer therapy.

Development and evaluation of hyaluronic acid-based polymeric micelles for targeted delivery of photosensitizer for photodynamic therapy in vitro

To enhance the effectiveness and specificity of photodynamic therapy (PDT) in CD44-overexpressing cancers, the hyaluronic acid-b-poly (d,l-lactide-co-glycolide) copolymer (HA-b-PLGA) was synthesized, and potent photosensitizer protoporphyrin IX (PpIX) loaded polymeric micelles were prepared. The formulation organic solvent, polymer concentration, and feeding weight ratio of PpIX to polymer were optimized. PpIX-loaded HA-b-PLGA micelles (PpIX HA-PLGA micelles) were obtained with a drug loading rate of 2%, encapsulation efficiency of 43%, average diameter of 213 nm and zeta potential of −24 mV. The PpIX HA-PLGA micelles exhibited enhanced phototoxicity toward A549 cells. A cellular uptake study indicated that the micelles were internalized by CD44-mediated endocytosis. Exposure of A549 cell spheroids to HA-PLGA micelles showed deeper penetration and improved phototoxicity compared with nanoparticle and free drug analogues. PpIX HA-PLGA micelles have great potential for CD44-targeting delivery in PDT treatment.

Dual pH-responsive multifunctional nanoparticles for targeted treatment of breast cancer by combining immunotherapy and chemotherapy.

Combination of immunotherapy and chemotherapy is becoming a promising new treatment for cancer. The major challenge is to target cancer and immune cells simultaneously and specifically. In this study, a dual pH-responsive multifunctional nanoparticle system based on poly(L-histidine) and hyaluronic acid was designed for co-loading R848 (immune-regulator) and doxorubicin (chemotherapeutic drug) through different encapsulation modes. By responding to the acidic pHs of tumor microenvironment and intracellular organelles, this multifunctional nanoparticle system could release R848 extracellularly and deliver DOX targetedly to breast cancer cells, thus achieving synergistic effects of immunotherapy and chemotherapy against breast cancer.

Tumor microenvironment dual-responsive core-shell nanoparticles with hyaluronic acid-shield for efficient co-delivery of doxorubicin and plasmid DNA.

As the tumor microenvironment (TME) develops, it is critical to take the alterations of pH value, reduction and various enzymes of the TME into consideration when constructing the desirable co-delivery systems. Herein, TME pH and enzyme dual-responsive core–shell nanoparticles were prepared for the efficient co-delivery of chemotherapy drug and plasmid DNA (pDNA). A novel pH-responsive, positively charged drug loading material, doxorubicin (DOX)-4-hydrazinobenzoic acid (HBA)-polyethyleneimine (PEI) conjugate (DOX-HBA-PEI, DHP), was synthesized to fabricate positively charged polyion complex inner core DHP/DNA nanoparticles (DDN). Hyaluronic acid (HA) was an enzyme-responsive shell which could protect the core and enhance the co-delivery efficiency through CD44-mediated endocytosis. The HA-shielded pH and enzyme dual-responsive nanoparticles (HDDN) were spherical with narrow distribution. The particle size of HDDN was 148.3±3.88 nm and the zeta potential was changed to negative (−18.1±2.03 mV), which led to decreased cytotoxicity. The cumulative release of DOX from DHP at pH 5.0 (66.4%) was higher than that at pH 7.4 (30.1%), which indicated the pH sensitivity of DHP. The transfection efficiency of HDDN in 10% serum was equal to that in the absence of serum, while the transfection of DDN was significantly decreased in the presence of 10% serum. Furthermore, cellular uptake studies and co-localization assay showed that HDDN were internalized effectively through CD44-mediated endocytosis in the tumor cells. The efficient co-delivery of DOX and pEGFP was confirmed by fluorescent image taken by laser confocal microscope. It can be concluded that TME dual-responsive HA-shielded core–shell nanoparticles could be considered as a promising platform for the co-delivery of chemotherapy drug and pDNA.

Synthesis and characterization of a bimodal nanoparticle based on the host-guest self-assembly for targeted cellular imaging

Multimodal imaging provides distinct advantages over traditional single modal imaging. The combined modalities of magnetic resonance imaging (MRI) and near-infrared imaging (NIR), in particular, provide a powerful tool for tumor diagnosis. In this study, a bimodal MRI and NIR self-assembled supramolecular nanoparticle was developed via the self-assembly of host-guest interactions between hyaluronic acid–β-cyclodextrin (HA–CD) and amantadine (Ad)-modified imaging agents (Gd–DOTA and NIR cyanine dye Cy7). The supramolecular HA–CD–GC nanoparticles (NPs) were characterized by transmission electron microscopy (TEM), Zeta potential, and dynamic light-scattering (DLS) experiments. The relaxivity and fluorescent properties of the NPs were also determined. HA–CD–GC NPs exhibited an enhanced relaxivity of 11.4mM−1S−1, which was three-fold higher than that of clinical Gd3+-chelated complex, for MRI imaging. Moreover, HA–CD–GC NPs displayed excellent fluorescence. In addition, HA–CD–GC NPs were internalized into tumor cells via HA-receptor CD44-mediated endocytosis. Therefore, the self-assembled HA–CD–GC NPs are effective targeted tumor cell imaging systems and have potential applications in cancer diagnosis and treatment.

Hyaluronic acid–nimesulide conjugates as anticancer drugs against CD44-overexpressing HT-29 colorectal cancer in vitro and in vivo

Carrier-mediated drug delivery systems are promising therapeutics for targeted delivery and improved efficacy and safety of potent cytotoxic drugs. Nimesulide is a multifactorial cyclooxygenase 2 nonsteroidal anti-inflammatory drug with analgesic, antipyretic and potent anticancer properties; however, the low solubility of nimesulide limits its applications. Drugs conjugated with hyaluronic acid (HA) are innovative carrier-mediated drug delivery systems characterized by CD44-mediated endocytosis of HA and intracellular drug release. In this study, hydrophobic nimesulide was conjugated to HA of two different molecular weights (360 kDa as HA with high molecular weight [HAH] and 43kDa as HA with low molecular weight [HAL]) to improve its tumor-targeting ability and hydrophilicity. Our results showed that hydrogenated nimesulide (N-[4-amino-2-phenoxyphenyl]methanesulfonamide) was successfully conjugated with both HA types by carbodiimide coupling and the degree of substitution of nimesulide was 1%, which was characterized by 1H nuclear magnetic resonance 400 MHz and total correlation spectroscopy. Both Alexa Fluor® 647 labeled HAH and HAL could selectively accumulate in CD44-overexpressing HT-29 colorectal tumor area in vivo, as observed by in vivo imaging system. In the in vitro cytotoxic test, HA–nimesulide conjugate displayed >46% cell killing ability at a nimesulide concentration of 400 µM in HT-29 cells, whereas exiguous cytotoxic effects were observed on HCT-15 cells, indicating that HA–nimesulide causes cell death in CD44-overexpressing HT-29 cells. Regarding in vivo antitumor study, both HAL–nimesulide and HAH–nimesulide caused rapid tumor shrinkage within 3 days and successfully inhibited tumor growth, which reached 82.3% and 76.4% at day 24 through apoptotic mechanism in HT-29 xenografted mice, without noticeable morphologic differences in the liver or kidney, respectively. These results indicated that HA–nimesulide with improved selectivity through HA/CD44 receptor interactions has the potential to enhance the therapeutic efficacy and safety of nimesulide for cancer treatment.

Multifunctional mesoporous silica nanoparticles modified with tumor-shedable hyaluronic acid as carriers for doxorubicin

In this paper, a CD44-targeted and redox-responsive drug delivery system based on mesoporous silica nanoparticles (MSNs) was synthesized by conjugating tumor-shedable hyaluronic acid (HA) on the surface of MSNs via disulfide bonds. Doxorubicin hydrochloride (DOX·HCl) was physically encapsulated into HA modified MSNs (MSNs/SS/HA@DOX) as a model drug. MSNs/SS/HA@DOX (40nm) had a high drug loading (14.1%) and redox-responsive drug release property. The cellular uptake behaviors of MSNs/SS/HA@DOX by HeLa and LO2 cells were evaluated by confocal laser scanning microscopy (CLSM) and flow cytometry (FCM). MSNs/SS/HA@DOX exhibited higher cellular uptake efficacy via CD44-mediated endocytosis by HeLa cells (CD44 over-expressed cells) than by LO2 cells (CD44 deficient cells). The in vitro cytotoxicity assay demonstrated that MSNs/SS/HA@DOX exhibited higher cytotoxicity to HeLa cells than to LO2 cells. These results indicated that MSNs/SS/HA@DOX might be promising as a multifunctional drug delivery system to improve the anti-tumor efficacy of chemotherapeutic drugs.

Systemic delivery of siRNA by hyaluronan-functionalized calcium phosphate nanoparticles for tumor-targeted therapy.

In this study, hyaluronan (HA)-functionalized calcium phosphate nanoparticles (CaP-AHA/siRNA NPs) were developed for an injectable and targetable delivery of siRNA, which were prepared by coating the alendronate-hyaluronan graft polymer (AHA) around the surface of calcium phosphate-siRNA co-precipitates. The prepared CaP-AHA/siRNA NPs had a uniform spherical core-shell morphology with an approximate size of 170 nm and zeta potential of -12 mV. The coating of hydrophilic HA improved the physical stability of nanoparticles over one month due to the strong interactions between phosphonate and calcium. In vitro experiments demonstrated that the negatively charged CaP-AHA/siRNA NPs could effectively deliver EGFR-targeted siRNA into A549 cells through CD44-mediated endocytosis and significantly down-regulate the level of EGFR expression. Also, the internalized CaP-AHA/siRNA NPs exhibited a pH-responsive release of siRNA, indicating that the acidification of lysosomes probably facilitated the disassembling of nanoparticles and the resultant ions sharply increased the inner osmotic pressure and thus expedited the release of siRNA from late lysosomes into the cytoplasm. Furthermore, in vivo tumor therapy demonstrated that high accumulation of CaP-AHA/siEGFR NPs in tumor led to a significant tumor growth inhibition with a specific EGFR gene silencing effect after intravenous administration in nude mice xenografted with A549 tumor, along with a negligible body weight loss. These results suggested that the CaP-AHA/siRNA NPs could be an effective and safe systemic siRNA delivery system for a RNAi-based tumor targeted therapy strategy.

Inhibition of cell proliferation and migration by chondroitin sulfate-g-polyethylenimine-mediated miR-34a delivery

Chondroitin sulfate was chemically conjugated to PEI25K through Michael addition to construct a non-viral gene carrier CS-PEI, and then the carrier was employed in miR-34a delivery to achieve the inhibition of cell proliferation and migration, using prostate tumor cell PC-3 as a model. The nanoparticle from CS-PEI and miR-34a at a mass ratio of 10 was prepared with particle size and zeta potential of 170.7nm and +42.2mV, respectively. Flow cytometry and fluorescence microscopy revealed that CS-PEI could efficiently induce the cellular uptake of miR-34a in a CD44-mediated endocytosis manner. Through CS-PEI-mediated miR-34a transfection, obvious cell apoptosis was observed with early apoptotic cells of 47.49%, and meanwhile the activation of caspase-3, -8 and -9, and decreased expression level of Bcl-2 were detected. Moreover, wound healing assay showed that CS-PEI/miR-34a transfection could inhibit the cell migration. Overall, CS-PEI is potentially employed as a promising tumor-targeting system for miR-34a delivery in tumor gene therapy.

Chemically conjugating poly(amidoamine) with chondroitin sulfate to promote CD44-mediated endocytosis for miR-34a delivery

Chemically conjugating poly(amidoamine) with chondroitin sulfate to promote CD44-mediated endocytosis for miR-34a delivery

Abstract 4471: The antitumor activity of hyaluronic acid nimuselide-NH2 bioconjugate (CA102N) in human colorectal cancer (CRC)

Abstract Carrier mediated drug delivery systems are promising next generation therapeutics for targeted delivery and improved efficacy and safety of cytotoxic drugs. Hyaluronic Acid conjugated drugs (HACD) are novel carrier-mediated drug delivery systems (Targeting Carrier™) characterized by CD44-mediated endocytosis of Hyaluronic Acid (HA) and intracellular drug release. The present study investigates the in vitro and in vivo antitumor activity of CA102N, an HA- Cyclooxygenase-2 inhibitor conjugate, HA-Nimesulide, currently in preclinical development. Cyclooxygenase-2 (COX-2) inhibitors are a class of compounds that are associated with anticancer properties. CA102N was able to selectively inhibit HCT116 and HT29, CRC cancer cell growth in vitro with an IC50 of 57.7 and 77.14 μM respectively. In in vivo studies, strong anti-tumor effects and rapid tumor shrinkage was observed within 3 days posttherapy in mice bearing HT-29 xenografts treated with either 1.5 or 4.5 mg/kg of relative amount of the conjugate. Further, full and sustained regression of tumors was also attained during the entire observational period (14 days) after the last dose. No treatment related toxicity was noticed in mice. HACD drug delivery systems may offer great advantages in the development of a new class of bioconjugated drugs for intracellular delivery and enhanced safety of potent cytotoxic drugs. Citation Format: Eskouhie Tchaparian. The antitumor activity of hyaluronic acid nimuselide-NH2 bioconjugate (CA102N) in human colorectal cancer (CRC). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4471. doi:10.1158/1538-7445.AM2015-4471

Hyaluronic acid-fabricated nanogold delivery of the inhibitor of apoptosis protein-2 siRNAs inhibits benzo[a]pyrene-induced oncogenic properties of lung cancer A549 cells

Benzo[a]pyrene (BaP), a component of cooking oil fumes (COF), promotes lung cancer cell proliferation and survival via the induction of inhibitor of apoptosis protein-2 (IAP-2) proteins. Thus knockdown of IAP-2 would be a promising way to battle against lung cancer caused by COF. Functionalized gold nanoparticle (AuNP) is an effective delivery system for bio-active materials. Here, biocompatible hyaluronic acid (HA) was fabricated into nanoparticles to increase the target specificity by binding to CD44-over-expressed cancer cells. IAP-2-specific small-interfering RNA (siRNAs) or fluorescein isothiocyanate (FITC) were then incorporated into AuNP-HA. Conjugation of IAP-2 siRNA into AuNPs-HA was verified by the UV–vis spectrometer and Fourier transform infrared spectrometer. Further studies showed that AuNP-HA/FITC were effectively taken up by A549 cells through CD44-mediated endocytosis. Incubation of BaP-challenged cells with AuNP-HA-IAP-2 siRNAs silenced the expression of IAP-2, decreased cell proliferation and triggered pronounced cell apoptosis by the decrease in Bcl-2 protein and the increase in Bax protein as well as the active form of caspases-3. The BaP-elicited cell migration and enzymatic activity of the secreted matrix metalloproteinase-2 were also substantially suppressed by treatment with AuNP-HA-IAP-2 siRNAs. These results indicated that IAP-2 siRNAs can be efficiently delivered into A549 cells by functionalized AuNP-HA to repress the IAP-2 expression and BaP-induced oncogenic events, suggesting the potential therapeutic application of IAP-2 siRNA or other siRNA-conjugated AuNP-HA composites to COF-induced lung cancer and other gene-caused diseases in the future.

Hyaluronic acid/chitosan nanoparticles for delivery of curcuminoid and its in vitro evaluation in glioma cells

The aim of this work was to evaluate the potential of polyelectrolyte complex nanoparticles (PENPs) based on hyaluronic acid/chitosan (HA/CS) as carriers for water-insoluble curcuminoid (CUR) and explore in vitro performance against brain glioma cells. PENPs were observed to be affected by the order of addition, mass ratios and initial concentrations of the HA/CS, pH and ionic strength. PENPs remained stable over a temperature range of 5–-55(C. CUR was successfully encapsulated into the PENPs. CUR-PENPs showed spherical shape with a mean diameter of 207nm and positive charge of 25.37mV. High encapsulation efficiency (89.9%) and drug loading (6.5%) was achieved. Drug release studies revealed initial burst release of drug from the PENPs up to 4h followed by sustained release pattern. DSC thermograms and XRD patterns showed that CUR was encapsulated inside the PENPs in a molecular or amorphous state. Compared with CUR-solution, CUR-PENPs showed stronger dose dependent cytotoxicity against C6 glioma cells and higher performance in uptake efficiency in C6 cells. Cellular uptake of CUR-PENPs was found to be governed by multi-mechanism in C6 cells, involving active endocytosis, macropinocytosis, clathrin-, caveolae-, and CD44-mediated endocytosis. In conclusion, CUR-PENPs might be a promising carrier for therapy of brain gliomas.

Chitosan-Based Polyelectrolyte Complexes as Potential Nanoparticulate Carriers: Physicochemical and Biological Characterization

To investigate the effect of polyelectrolytes on the formation and physicochemical properties of chitosan nanoparticles (CS-NPs) used for the delivery of an anticancer drug, doxorubicin (DOX). Three DOX-loaded CS-NPs were formulated with tripolyphosphate (CS-TP/DOX NPs), dextran sulfate (CS-DS/DOX NPs), and hyaluronic acid (CS-HA/DOX NPs) by using ionotropic gelation or complex coacervation. CS-TP/DOX NPs were the smallest, with an average size of ~100nm and a narrow size distribution, while CS-DS/DOX and CS-HA/DOX NPs were ~200nm in size. Transmission electron microscopy clearly showed a spherical shape for all the NPs. The strong binding affinity of DOX for the multiple sulfate groups in DS resulted in a sustained release profile from CS-DS/DOX NPs at pH7.4, while CS-HA/DOX NPs exhibited faster DOX release. This trend was also present under acidic conditions, where release of DOX was significantly augmented because of polymer protonation. Compared to CS-TP/DOX or CS-DS/DOX NPs, CS-HA/DOX NPs showed superior cellular uptake and cytotoxicity in MCF-7 and A-549 cells, because of their ability to undergo CD44-mediated endocytosis. Pharmacokinetic studies clearly showed that all CS-NPs tested significantly improved DOX plasma circulation time and decreased its elimination rate constant. Consistent with the in vitro release data, CS-DS/DOX NPs exhibited a relatively better DOX plasma profile and enhanced blood circulation, compared to CS-HA/DOX or CS-TP/DOX NPs. Overall, these results demonstrated how NP design can influence their function. Taken together, CS-based polyelectrolyte complexes could provide a versatile delivery system with enormous potential in the pharmaceutical and biomedical sectors.

Multifunctional Tumor-Targeting Nanocarriers Based on Hyaluronic Acid-Mediated and pH-Sensitive Properties for Efficient Delivery of Docetaxel

The objective of this work was to develop a multifunctional tumor-targeting nanocarrier based on the mechanism of CD44-mediated endocytosis and pH-induced drug release to improve the therapeutic efficacy of docetaxel (DTX). Hyaluronic acid-coated docetaxel-loaded cholesteryl hemisuccinate vesicles (HA-CHEMS vesicles) were prepared. The physiochemical properties and pH-dependent drug release of HA-CHEMS vesicles were evaluated. The HA-CHEMS vesicles were investigated for CD44-mediated internalization and in vitro cell viability using MCF-7,A549 and L929 cells.In addition,tissue distribution as well as antitumor efficacy was also evaluated in MCF-7 tumor-bearing mouse model. The particle size and zeta potential of HA-CHEMS vesicles were 131.4 ± 6.2nm and -13.3 ± 0.04mV,respectively. The in vitro drug release results demonstrated a pH-responsive drug release under different pH conditions. In vitro cell viability tests suggested that the encapsulation of DTX in HA-CHEMS vesicles led to more than 51.6-fold and 46.3-fold improved growth inhibition in MCF-7 and A549 cell lines,respectively compared to Taxotere®. From the cell uptake studies,the coumarin 6-loaded HA-CHEMS vesicles enhanced intracellular fluorescent intensity in the CD44-overexpressing cell line (MCF-7). Biodistribution studies revealed selective accumulation of HA-CHEMS vesicles in the MCF-7 bearing BalB/c nude mice as a result of passive accumulation and active targeting (CD44-mediated endocytosis). Compared to Taxotere®,HA-CHEMS vesicles exhibited higher antitumor activity by reducing tumor volume (P < 0.05) and drug toxicity,demonstrating the success of the multifunctional targeting delivery. This work corresponds to the preparation of a multifunctional tumor-targeted delivery system. Our investigation shows that hyaluronan-bearing docetaxel-loaded cholesteryl hemisuccinate vesicles (HA-CHEMS vesicles) is a highly promising therapeutic system,leading to tumor regression after intravenous administration without visible toxicity.

Biodegradable self-assembled nanoparticles of poly (d,l-lactide-co-glycolide)/hyaluronic acid block copolymers for target delivery of docetaxel to breast cancer

To develop biodegradable docetaxel-loaded self-assembled nanoparticles of poly (d,l-lactide-co-glycolide)/hyaluronic acid block copolymers were successfully synthesized. These copolymers could form nanoparticles with small size (<200 nm), an acceptable CMC (∼7.9 mg/L), typical core/shell structure and superior stability in one week. DTX-loaded PLGA502H-b-HA5.6k nanoparticles (DTX/SANPs) showed a biphasic release pattern within 120 h, and exhibited enhanced cytotoxicity toward CD44-overexpressing MDA-MB-231 cells. Cellular uptake study indicated that PLGA502H-b-HA5.6k nanoparticles (SANPs) were taken up in MDA-MB-231 cells by CD44-mediated endocytosis. Pharmacokinetics study revealed DTX/SANPs could prolong the circulation of DTX in the blood. In vivo studies demonstrated that SANPs exhibited enhanced tumor targeting and antitumor activity with lower systemic toxicity. In conclusion, DTX/SANPs have great potential for targeted chemotherapy for CD44-overexpressing breast cancer.

The Copolymer of Poly(2‐dimethylaminoethyl methacrylate) and Methacrylated Chondroitin Sulfate with Low Cytotoxicity for Gene Delivery

Poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) is one of the most potent synthetic nonviral gene-delivery vectors because of its high transfection efficiency. However, the cytotoxicity of PDMAEMA is a major concern for its clinical applications. An anionic crosslinker is synthesized based on a natural polysaccharide, chondroitin sulfate (CS), by introducing methacrylate groups (CSMA). By systematically adjusting the substitution degree of methacrylation on CS and the weight percent of CSMA and PDMAEMA, sol-type copolymers are obtained as a gene-delivery vector. The combination of CS and PDMAEMA is expected not only to reduce the cytotoxicity of PDMAEMA, but also to facilitate better transfection efficiency than PDMAEMA because of the recognition of CS by CD44 receptors on cell surfaces. Two CSMA-modified PDMAEMA copolymers with different CSMA constituents are selected and their polyplexes prepared with plasmid DNA. The cytotoxicity and gene transfection efficiency of the polyplexes are tested and compared with those of PDMAEMA/pDNA. The copolymers of CSMA and PDMAEMA show significantly improved cell viability as compared with PDMAEMA. Their formed polyplexes with pDNA also show lower cytotoxicity than does PDMAEMA/pDNA. The transfection efficiency remarkably increases as the CSMA-modified PDMAEMA/pDNA polyplex is prepared at a weight ratio of 2.4. The internalization mechanism of CSMA-modified PDMAEMA/pDNA in HEK 293T cells is mainly based on caveolae-mediated endocytosis. However, both caveolae-mediated and CD44-mediated endocytosis mechanisms are involved in U87 cells.