Preparation of novel sulfated polysaccharide-carboxymethyl-5-fluorouracil-folic acid conjugates for targeted anticancer drug delivery

GFP1, a sulfated polysaccharide extracted from Grateloupia filicina, exhibits remarkable immunomodulatory activity. To reduce the side effects of 5-fluorouracil (5-FU), GFP1 was employed as a macromolecular carrier to synthesize of GFP1-C-5-FU by reacting with carboxymethyl-5-fluorouracil (C-5-FU). Subsequently, this new compound was reacted with folic acid (FA) through an ester bond, forming novel conjugates named GFP1-C-5-FU-FA. Nuclear magnetic resonance analysis confirmed the formation of GFP1-C-5-FU-FA. In vitro drug release studies revealed that the cumulative release rate of C-5-FU reached 46.9 % in phosphate buffer (pH 7.4) after 96 h, a rate significantly higher than that of the control groups, indicating the controlled drug release behavior of GFP1-C-5-FU-FA. Additionally, in vitro anticancer assays demonstrated the potent anticancer activity of GFP1-C-5-FU-FA conjugates, as evidenced by the reduced viability of HeLa and AGS cancer cells, along with increased levels of apoptosis and cellular uptake. Western blot analysis indicated that the GFP1-C-5-FU-FA conjugate effectively enhanced phosphorylation in cancer cells through the NF-kB and MAPK pathways, thereby promoting apoptosis. These findings highlight the potential of folate-targeted conjugates in efficiently treating HeLa and AGS cancer cells in vitro and lay a robust theoretical groundwork for future in vivo anti-cancer research involving these cells.

A novel sulfated mannan-carboxymethyl-5-fluorouracil-folic acid conjugates for targeted anticancer drug delivery

CFP₂ is a sulfated polysaccharide isolated from Codium fragile that shows excellent immunomodulatory activity. To reduce the side effects of 5-fluorouracil (5-FU), CFP₂ was used as a macromolecular carrier to react with carboxymethyl-5-fluorouracil (C-5-FU) to form CFP₂-C-5-FU, which further reacted with folic acid (FA) via an ester bond to form novel conjugates (CFP₂-C-5-FU-FA). CFP₂-C-5-FU-FA was confirmed by nuclear magnetic resonance (NMR) analysis. In vitro drug release results showed that the cumulative release rate of C-5-FU was 49.9% in phosphate buffer (pH 7.4) after 96 h, which was much higher than that of the other groups, indicating that CFP2-C-5-FU-FA showed controlled drug release behavior. CFP₂-C-5-FU-FA also exhibited enhanced apoptosis and cellular uptake in vitro. Further, intravenous administration of CFP₂-C-5-FU-FA in an HCT-116 cell-bearing xenograft mouse showed that the conjugates were safe and effective drug delivery systems. These results suggest that folate-targeted conjugates can be used effectively for efficient chemotherapy of colorectal cancer.

Preparation and characterization of folic acid conjugated sulfated polysaccharides on NK cell activation and cellular uptake in HeLa cells

In this study, the sulfated polysaccharide (SP) of Codium fragile was conjugated to folic acid (SP-FA). FT-IR and ¹H NMR techniques revealed the occurrence of esterification reaction between the hydroxyl group of SP and the γ-carboxyl group of FA that confirming the SP-FA conjugation. SP and SP-FA did not show any direct toxicity on NK cells and HeLa cells. However, the treatment of SP and SP-FA enhance the NK cells cytotoxicity against HeLa cells by the upregulation of IFN-γ, TNF-α, perforin, and Granzyme-B. Moreover, NK cells activation was stimulated through NF-кB and MAPK pathways. The binding capacity studies exposed the targeting ability of HeLa cells by folate receptor (FR) which was assessed by a confocal quantitative image cytometer analysis. These results indicate that SP-FA could be used as selective drug delivery systems for targeting FR-overexpressed cancer cells with less toxicity.

In Vitro and In Vivo Evaluation of Novel DTX-Loaded Multifunctional Heparin-Based Polymeric Micelles Targeting Folate Receptors and Endosomes

BACKGROUND

The development of biocompatible tumor-targeting delivery systems for anticancer agents is essential for efficacious cancer chemotherapy. Nanoparticles, as drug delivery cargoes for cancer therapy, are rapidly improving to overcome the limitations of conventional chemotherapeutic agents. Heparin-modified nanoparticles are currently being considered as one of the favorable carriers for the delivery of chemotherapeutics to cancer tissues.

OBJECTIVE

This study was aimed at evaluating the in vitro and in vivo antitumor activity of a novel targeted, pH-sensitive, heparin-based polymeric micelle loaded with the poorly water-soluble anticancer drug, docetaxel (DTX). The micelles could overcome the limited water solubility, non-specific distribution, and insufficient drug concentration in tumor tissues.

METHODS

DTX-loaded folate targeted micelles were prepared and evaluated for physicochemical properties, drug release, in vitro cellular uptake and cytotoxicity in folate receptor-positive and folate receptor-negative cells. Furthermore, the antitumor activity of DTX-loaded micelles was evaluated in the tumor-bearing mice. Some related patents were also studied in this research.

RESULTS

The heparin-based targeted micelles exhibited higher in vitro cellular uptake and cytotoxicity against folate receptor over-expressed cells due to the specific receptor-mediated endocytosis. DTX-loaded micelles displayed greater antitumor activity, higher anti-angiogenesis effects, and lower systemic toxicity compared with free DTX in a tumor-induced mice model as confirmed by tumor growth monitoring, immunohistochemical evaluation, and body weight shift. DTX-loaded targeting micelles demonstrated no considerable toxicity on major organs of tumor-bearing mice compared with free DTX.

CONCLUSION

Our results indicated that DTX-loaded multifunctional heparin-based micelles with desirable antitumor activity and low toxicity possess great potential as a targeted drug delivery system in the treatment of cancer.

Novel pH-triggered biocompatible polymeric micelles based on heparin-α-tocopherol conjugate for intracellular delivery of docetaxel in breast cancer

In this study, pH-triggered polymeric micelle comprising α-tocopherol (TOC) and heparin (HEP) was developed and loaded with docetaxel (DTX). The amphiphilic copolymer was synthesized by grafting TOC onto HEP backbone by a pH-cleavable bond. DTX-loaded micelles were characterized in terms of critical micelle concentration (CMC), particle size, zeta potential, entrapment efficiency (EE), pH-responsive behavior, and drug release. In vitro cytotoxicity of the micelles against breast cancer cells was investigated by MTT assay. The cellular uptake of coumarin-loaded micelles was also evaluated. Furthermore, the pharmacokinetics of DTX-loaded micelles was evaluated and compared with that of Taxotere^®.HEP-CA-TOC copolymers showed low CMC values and high EE. At pH 7.4, the micelles remained stable in size and shape, whereas considerable changes in particle size and morphology were observed at pH 5.5. DTX-loaded micelles showed pH-dependent drug release profiles. Coumarin-loaded micelles showed higher cellular uptake than free coumarin. Therefore, the DTX-loaded micelles showed more toxicity against breast cancer cells than free DTX. A significant increase in T_1/2 β, AUC_0-∞ and MRT was observed in DTX-loaded micelle treated group as compared to the group treated with Taxotere^®.The results suggest that the pH-sensitive HEP-modified micelles could be promising for enhanced intracellular drug delivery of DTX for cancer treatment.

The preparation of pH and GSH dual responsive thiolated heparin/DOX complex and its application as drug carrier

The complicated preparation procedure and carrier's suspicious biocompatibility are two major limitations for traditional drug carrier. In this manuscript, a novel polyion complex (PIC) was prepared by simply mixing two biocompatible components, thiolated heparin and doxorubicin (DOX), and subsequently crosslinking under atmosphere, so that it can overcome the above limitations. The PIC's particle size kept stable for one week storage in PBS, and the particles wouldn't decomposed by the dilution, indicating excellent storage and anti-dilution stability resulting from the crosslinking. The PIC can release the larger amount of DOX in acidic environment than psychological environment, and largest amount in acidic and glutathione (GSH) environment, showing the pH and GSH dual sensitive drug release behavior. Furthermore, the PIC exhibited obvious tumor inhibition effect in vivo as well as long circulation ability and low heart toxicity by anti-tumor tests on tumor-bearing mice. Consequently, as-prepared PIC shows promising potential in drug carrier application.

A strategy using mesoporous polymer nanospheres as nanocarriers of Bcl-2 siRNA towards breast cancer therapy

Small interference RNA (siRNA) has demonstrated unprecedented potential as a therapy for drug-resistant cancer. However, efficient cellular delivery is still a challenge due to hydrolytic sensitivity and poor cellular uptake of siRNA. Strategies to conjugate siRNA to the delivery vehicle and activate innate immunity have shown low in vivo efficacy. Therefore, nanomedicine approaches have become the main focus in this field. B-cell lymphoma 2 (Bcl-2) is the founding member of the Bcl-2 family of regulatory proteins that regulate cell death (apoptosis), by either inducing (pro-apoptotic) or inhibiting (anti-apoptotic) apoptosis. In this report, a nanomedicine system is constructed using Bcl-2 siRNA as the therapeutic agent and mesoporous polymer nanosphere (MPN) carriers to both improve cellular internalization and achieve Bcl-2 silencing and cell apoptosis. MPNs were prepared through a two-stage hydrothermal process at two different temperatures, which was deliberately designed to form nanospheres via self-assembly and create mesoporous structures by removing the pore-forming templates. Such MPNs were proved to be biodegradable. Without any carbonization process, MPNs still keep many active groups which endow them with excellent properties for functionalization purposes. Finally, the FA-targeted-Bcl-2-siRNA-loaded nanoparticles were constructed by a layer-by-layer assembly by electrostatic interactions after nitrification. These nanoparticles were efficiently delivered into breast cancer (BC) cells, showing a significant sequence-specific inhibition of Bcl-2 mRNA expression in BC cells, enhanced tumor cell apoptosis and tumor therapeutic efficacy. Taken together, this study establishes a novel therapeutic system for cancer therapy.

Glucose-Reduced Graphene Oxide with Excellent Biocompatibility and Photothermal Efficiency as well as Drug Loading

In the present work, we report a facile and rapid green strategy to fabricate functionalized reduced nano-graphene oxide (nrGO) as a cooperative nanotemplate for both photothermal therapy and drug loading. Graphite oxide was firstly oxidated by nitronium ions (NO2 (+)) solution at the aid of microwave heating to obtain nano-GO (nGO) with about 50 nm of diameter, and the nGO was then reduced in pure glucose at 135 °C for 30 min to obtain nrGO with about 40 nm of diameter. The nrGO exhibits excellent biocompatibility including stable dispersibility in cell culture medium and rapid cellular uptake as well as non-cytotoxicity up to 100 μg/mL. Absorption of the nrGO at 808 nm wavelength increased more than 10-folds compared with nGO. Moreover, the nrGO has the ability to load about 317 % (w/w) of doxorubicin (DOX), and the loaded DOX could be effectively released by acid condition and/or glutathione (GSH) and/or heating. Finally, a greater cancer cell death efficacy was observed in nrGO/DOX-treated cells with GSH and heating stimulation respectively or their combination. Collectively, the nrGO developed here is an outstanding cooperative nano-platform for high-efficiency photothermal therapy and controllable drug delivery.

Carbohydrate-based amphiphilic nano delivery systems for cancer therapy

Nanoparticles (NPs) are novel drug delivery systems that have been attracting more and more attention in recent years, and have been used for the treatment of cancer, infection, inflammation and other diseases. Among the numerous classes of materials employed for constructing NPs, organic polymers are outstanding due to the flexibility of design and synthesis and the ease of modification and functionalization. In particular, NP based amphiphilic polymers make a great contribution to the delivery of poorly-water soluble drugs. For example, natural, biocompatible and biodegradable products like polysaccharides are widely used as building blocks for the preparation of such drug delivery vehicles. This review will detail carbohydrate based amphiphilic polymeric systems for cancer therapy. Specifically, it focuses on the nature of the polymer employed for the preparation of targeted nanocarriers, the synthetic methods, as well as strategies for the application and evaluation of biological activity. Applications of the amphiphilic polymer systems include drug delivery, gene delivery, photosensitizer delivery, diagnostic imaging and specific ligand-assisted cellular uptake. As a result, a thorough understanding of the relationship between chemical structure and biological properties facilitate the optimal design and rational clinical application of the resulting carbohydrate based nano delivery systems for cancer therapy.

An overview of the effective combination therapies for the treatment of breast cancer

Breast cancer (BC) is generally classified based on the receptors overexpressed on the cell nucleus, which include hormone receptors such as progesterone (PR) and estrogen (ER), and HER2. Triple-negative breast cancer (TNBC) is a type of cancer that lacks any of these three types of receptor proteins (ER/PR/HER2). Tumor cells exhibit drug resistant phenotypes that decrease the efficacy of chemotherapeutic treatments. Generally, drug resistance has a genetic basis that is caused by an abnormal gene expression, nevertheless, there are several types of drug resistance: efflux pumps reducing the cellular concentration of the drug, alterations in membrane lipids that reduce cellular uptake, increased or altered drug targets, metabolic alteration of the drug, inhibition of apoptosis, repair of the damaged DNA, and alteration of the cell cycle checkpoints. The use of "combination therapy" is recognized as an efficient solution to treat human diseases, in particular, breast cancer. In this review, we give examples of different nanocarriers used to co-deliver multiple therapeutics (chemotherapeutic agent and nucleic acid) to drug-resistant tumor cells, and lastly, we give our recommendations for the future directions for the co-delivery treatments.

Highly swellable and biocompatible graphene/heparin-analogue hydrogels for implantable drug and protein delivery

The GO/heparin-analogue hydrogels with hemo- and cyto-compatibility could be used in various biomedical fields, such as drug and protein delivery, tissue regeneration scaffold, and other biomedical systems.

Folate-decorated hydrophilic three-arm star-block terpolymer as a novel nanovehicle for targeted co-delivery of doxorubicin and Bcl-2 siRNA in breast cancer therapy

To minimize the side effects and enhance the efficiency of chemotherapy, a novel folate-decorated hydrophilic cationic star-block terpolymer, [poly(l-glutamic acid γ-hydrazide)-b-poly(N,N-dimethylaminopropyl methacrylamide)]3-g-poly(ethylene glycol) ((PGAH-b-PDMAPMA)3-g-PEG), with disulfide linkages between the PEG and PDMAPMA blocks, was developed for targeted co-delivery of doxorubicin and Bcl-2 small interfering RNA (siRNA) into breast cancer cells. The terpolymer was synthesized by a combination of ring-opening polymerization, reversible addition-fragmentation chain transfer polymerization, PEGylation and hydrazinolysis. The chemical structures of the polymers were confirmed by (1)H-NMR analysis. The terpolymer could conjugate doxorubicin via an acid-labile hydrazone linkage and simultaneously efficiently complex siRNA through electrostatic interaction at N/P ratios of ⩾4:1 to form "two-in-one" nanomicelleplexes, which displayed a spherical shape and had an average size of 101.3 nm. The doxorubicin loading efficiency and content were 61.0 and 13.23%, respectively. The cytotoxicity, drug release profile, targeting ability, cellular uptake and intracellular distribution of the nanomicelleplexes were evaluated in vitro. We found that the release behaviors of doxorubicin and siRNA had a pH/reduction dual dependency. They were released faster under reductive acidic conditions (pH 5.0, glutathione: 10mM) than under physiological conditions (pH 7.4). The folate-decorated nanomicelleplexes could deliver doxorubicin and Bcl-2 siRNA more efficiently into the same MCF-7 cell and exhibited a higher cytotoxicity than non-targeted nanomicelleplexes. These results indicate that the terpolymer could act as an efficient vehicle for targeted intracellular co-delivery of doxorubicin and therapeutic siRNA in cancer therapy.

Robust, highly elastic and bioactive heparin-mimetic hydrogels

We construct robust, highly elastic, and bioactive graphene oxide doped heparin-mimetic hydrogels for use in drug delivery and other potential biomedical applications.

Photodynamic therapy of oligoethylene glycol dendronized reduction-sensitive porphyrins

OEGylation of porphyrins via a disulfide linkage to form a novel class of dendritic porphyrin photosensitizers (PSs) is presented.

DOX-encapsulated intelligent PAA-g-PEG/PEG–Fa polymeric micelles for intensifying antitumor therapeutic effect via active-targeted tumor accumulation

Reduction-breakable active targeting polymeric micelles as drug delivery systems could improve delivery efficiency by tumor-specific recognition.

Nanodrug delivery systems: a promising technology for detection, diagnosis, and treatment of cancer

Nanotechnology has enabled the development of novel therapeutic and diagnostic strategies, such as advances in targeted drug delivery systems, versatile molecular imaging modalities, stimulus responsive components for fabrication, and potential theranostic agents in cancer therapy. Nanoparticle modifications such as conjugation with polyethylene glycol have been used to increase the duration of nanoparticles in blood circulation and reduce renal clearance rates. Such modifications to nanoparticle fabrication are the initial steps toward clinical translation of nanoparticles. Additionally, the development of targeted drug delivery systems has substantially contributed to the therapeutic efficacy of anti-cancer drugs and cancer gene therapies compared with nontargeted conventional delivery systems. Although multifunctional nanoparticles offer numerous advantages, their complex nature imparts challenges in reproducibility and concerns of toxicity. A thorough understanding of the biological behavior of nanoparticle systems is strongly warranted prior to testing such systems in a clinical setting. Translation of novel nanodrug delivery systems from the bench to the bedside will require a collective approach. The present review focuses on recent research efforts citing relevant examples of advanced nanodrug delivery and imaging systems developed for cancer therapy. Additionally, this review highlights the newest technologies such as microfluidics and biomimetics that can aid in the development and speedy translation of nanodrug delivery systems to the clinic.

Heparin-functionalized polymeric biomaterials in tissue engineering and drug delivery applications

Heparin plays an important role in many biological processes via its interaction with various proteins, and hydrogels and nanoparticles comprising heparin exhibit attractive properties, such as anticoagulant activity, growth factor binding, and antiangiogenic and apoptotic effects, making them great candidates for emerging applications. Accordingly, this review summarizes recent efforts in the preparation of heparin-based hydrogels and formation of nanoparticles, as well as the characterization of their properties and applications. The challenges and future perspectives for heparin-based materials are also discussed. Prospects are promising for heparin-containing polymeric biomaterials in diverse applications ranging from cell carriers for promoting cell differentiation to nanoparticle therapeutics for cancer treatment.

Poly(acrylic acid) modified lanthanide-doped GdVO4 hollow spheres for up-conversion cell imaging, MRI and pH-dependent drug release

In this study, multifunctional poly(acrylic acid) modified lanthanide-doped GdVO(4) nanocomposites [PAA@GdVO(4): Ln(3+) (Ln = Yb/Er, Yb/Ho, Yb/Tm)] were constructed by filling PAA hydrogel into GdVO(4) hollow spheres via photoinduced polymerization. The up-conversion (UC) emission colors (green, red and blue) can be tuned by changing the codopant compositions in the matrices. The composites have potential applications as bio-probes for cell imaging. Meanwhile, the hybrid spheres can act as T(1) contrast agents for magnetic resonance imaging (MRI) owing to the existence of Gd(3+) ions on the surface of composites. Due to the nature of PAA, DOX-loaded PAA@GdVO(4):Yb(3+)/Er(3+) system exhibits pH-dependent drug releasing kinetics. A lower pH offers a faster drug release rate. Such character makes the loaded DOX easily released at cancer cells. The cell uptake process of drug-loaded composites was observed by using confocal laser scanning microscopy (CLSM). The results indicate the potential application of the multifunctional composites as theragnostics (effective bimodal imaging probes and pH-responsive drug carriers).

Dendronized heparin-doxorubicin conjugate based nanoparticle as pH-responsive drug delivery system for cancer therapy

Heparin drug conjugates are currently investigated as excellent candidates for drug delivery vehicles. In this study, we report the preparation and characterization of dendronized heparin-doxorubicin (heparin-DOX) conjugate as pH-sensitive drug delivery vehicle by combination of the features of dendrimer and heparin. Dynamic light scattering (DLS) and transmission electron microscope (TEM) studies demonstrated the dendronized heparin-DOX conjugate self-assembled into compact nanoparticles with negatively charged surface. The nanoparticles with 9.0 wt% (weight percent) of doxorubicin (DOX) showed pH-sensitive property due to the faster drug release rate at pH 5.0 and slow release rate at pH 7.4 aqueous. The nanoparticles were shown to effectively kill cancer cells in vitro. Notablely, the nanoparticles resulted in strong antitumor activity, high antiangiogenesis effects and induced apoptosis on the 4T1 breast tumor model due to the evidences from mice weight shifts, tumor weights, tumor growth curves, immunohistochemical assessment and histological analysis. It's also noteworthy that dendronized heparin and its nanoparticle with drug demonstrated no significant toxicity to healthy organs of both tumor-bearing and healthy mice, which was confirmed by histological analysis compared with free drug DOX. The dendronized heparin-DOX conjugate based nanopatilce with high antitumor activity and low side effects may be therefore a potential nanoscale drug delivery vehicle for breast cancer therapy.