Four-arm PEG cross-linked hyaluronic acid hydrogels containing PEGylated apoptotic TRAIL protein for treating pancreatic cancer

Innovative theranostic hydrogels for targeted gastrointestinal cancer treatment

Gastrointestinal tumors are the main causes of death among the patients. These tumors are mainly diagnosed in the advanced stages and their response to therapy is unfavorable. In spite of the development of conventional therapeutics including surgery, chemotherapy, radiotherapy and immunotherapy, the treatment of these tumors is still challenging. As a result, the new therapeutics based on (nano)biotechnology have been introduced. Hydrogels are polymeric 3D networks capable of absorbing water to swell with favorable biocompatibility. In spite of application of hydrogels in the treatment of different human diseases, their wide application in cancer therapy has been improved because of their potential in drug and gene delivery, boosting chemotherapy and immunotherapy as well as development of vaccines. The current review focuses on the role of hydrogels in the treatment of gastrointestinal tumors. Hydrogels provide delivery of drugs (both natural or synthetic compounds and their co-delivery) along with gene delivery. Along with delivery, hydrogels stimulate phototherapy (photothermal and photodynamic therapy) in the suppression of these tumors. Besides, the ability of hydrogels for the induction of immune-related cells such as dendritic cells can boost cancer immunotherapy. For more specific cancer therapy, the stimuli-responsive types of hydrogels including thermo- and pH-sensitive hydrogels along with their self-healing ability have improved the site specific drug delivery. Moreover, hydrogels are promising for diagnosis, circulating tumor cell isolation and detection of biomarkers in the gastrointestinal tumors, highlighting their importance in clinic. Hence, hydrogels are diagnostic and therapeutic tools for the gastrointestimal tumors.

Hydrogel-Based Therapeutics for Pancreatic Ductal Adenocarcinoma Treatment

Pancreatic ductal adenocarcinoma (PDAC), one of the deadliest malignancies worldwide, is characteristic of the tumor microenvironments (TME) comprising numerous fibroblasts and immunosuppressive cells. Conventional therapies for PDAC are often restricted by limited drug delivery efficiency, immunosuppressive TME, and adverse effects. Thus, effective and safe therapeutics are urgently required for PDAC treatment. In recent years, hydrogels, with their excellent biocompatibility, high drug load capacity, and sustainable release profiles, have been developed as effective drug-delivery systems, offering potential therapeutic options for PDAC. This review summarizes the distinctive features of the immunosuppressive TME of PDAC and discusses the application of hydrogel-based therapies in PDAC, with a focus on how these hydrogels remodel the TME and deliver different types of cargoes in a controlled manner. Furthermore, we also discuss potential drug candidates and the challenges and prospects for hydrogel-based therapeutics for PDAC. By providing a comprehensive overview of hydrogel-based therapeutics for PDAC treatment, this review seeks to serve as a reference for researchers and clinicians involved in developing therapeutic strategies targeting the PDAC microenvironment.

TRAIL-modified, doxorubicin-embedded periodic mesoporous organosilica nanoparticles for targeted drug delivery and efficient antitumor immunotherapy

Traditional anticancer treatments directly target tumor cells. In contrast, cancer immunotherapy fortifies host immunity. Nanoparticles that incorporate both immunomodulatory and chemotherapeutic agents regulate the tumor microenvironment by activating immune cells and enhancing antitumor immunity. Nanoparticle-based cancer immunotherapy has received considerable attention and has been extensively studied in recent years. In this study, we developed a targeted drug delivery system to enhance immunotherapeutic efficacy and overcome drug resistance by inducing tumor apoptosis and immunogenic cell death (ICD), and activating immune cells. Periodic mesoporous organosilica nanoparticles (PMOs) bore tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on their surfaces, and their inner cores were loaded with doxorubicin (DOX). TRAIL enhanced the nanoparticle-targeting capacity and worked synergistically with DOX against breast cancer cells in vitro and in vivo. Furthermore, we revealed for the first time the ability of PMOs to activate dendritic cells (DCs) and elevate ICD levels of DOX in vitro, and TRAIL further enhances the immunomodulatory function of PMOs. Systemic exposure to DOX@PMO-hT induced an immune response, activated DCs and CD4⁺ and CD8⁺ T cells, and significantly suppressed tumor growth in a 4T1-bearing immunocompetent mouse model. Overall, our study demonstrates that TRAIL-modified, DOX-embedded PMO nanoparticles represent a good candidate for tumor-targeted immunotherapy, which has relatively superior therapeutic efficacy and highly promising future application prospects. STATEMENT OF SIGNIFICANCE: This study revealed for the first time the ability of PMOs to elevate ICD levels and activate DCs in vitro. The results explained the immunomodulatory function of PMOs and demonstrated the synergistic effects of TRAIL and DOX in triple-negative breast cancer. In addition, immunomodulatory effects of the drug delivery vectors constructed in this study were verified in vivo.

TRAIL/S-layer/graphene quantum dot nanohybrid enhanced stability and anticancer activity of TRAIL on colon cancer cells

Tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL), known as a cytokine of the TNF superfamily, is considered a promising antitumor agent due to its ability to selectively induce apoptosis in a wide variety of cancer cells. However, failure of its successful translation into clinic has led to development of nano-based platforms aiming to improve TRAIL therapeutic efficacy. In this regard, we fabricated a novel TRAIL-S-layer fusion protein (S-TRAIL) conjugated with graphene quantum dots (GQDs) to benefit both the self-assembly of S-layer proteins, which leads to elevated TRAIL functional stability, and unique optical properties of GQDs. Noncovalent conjugation of biocompatible GQDs and soluble fusion protein was verified via UV–visible and fluorescence spectroscopy, size and ζ-potential measurements and transmission electron microscopy. The potential anticancer efficacy of the nanohybrid system on intrinsically resistant cells to TRAIL (HT-29 human colon carcinoma cells) was investigated by MTT assay and flow cytometry, which indicated about 80% apoptosis in cancer cells. These results highlight the potential of TRAIL as a therapeutic protein that can be extensively improved by taking advantage of nanotechnology and introduce S-TRAIL/GQD complex as a promising nanohybrid system in cancer treatment.

Challenges and recent trends with the development of hydrogel fiber for biomedical applications

Hydrogel is the most emblematic soft material which possesses significantly tunable and programmable characteristics. Polymer hydrogels possess significant advantages including, biocompatible, simple, reliable and low cost. Therefore, research on the development of hydrogel for biomedical applications has been grown intensely. However, hydrogel development is challenging and required significant effort before the application at an industrial scale. Therefore, the current work focused on evaluating recent trends and issues with hydrogel development for biomedical applications. In addition, the hydrogel's development methodology, physicochemical properties, and biomedical applications are evaluated and benchmarked against the reported literature. Later, biomedical applications of the nano-cellulose-based hydrogel are considered and critically discussed. Based on a detailed review, it has been found that the surface energy, intermolecular interactions, and interactions of hydrogel adhesion forces are major challenges that contribute to the development of hydrogel. In addition, compared to other hydrogels, nanocellulose hydrogels demonstrated higher potential for drug delivery, 3D cell culture, diagnostics, tissue engineering, tissue therapies and gene therapies. Overall, nanocellulose hydrogel has the potential for commercialization for different biomedical applications.

Photoreactive-proton-generating hyaluronidase/albumin nanoparticles-loaded PEG-hydrogel enhances antitumor efficacy and disruption of the hyaluronic acid extracellular matrix in AsPC-1 tumors

Depletion of tumor extracellular matrix (ECM) is viewed as a promising approach to enhance the antitumor efficacy of chemotherapeutic-loaded nanoparticles. Hyaluronidase (HAase) destroys hyaluronic acid-based tumor ECM, but it is active solely at acidic pHs of around 5.0 and is much less active at physiological pH. Herein, we report the development of our novel UV-light-reactive proton-generating and hyaluronidase-loaded albumin nanoparticles (o-NBA/HAase-HSA-NPs). The method to prepare the nanoparticles was based on pH-jump chemistry using o-nitrobenzaldehyde (o-NBA) in an attempt to address the clinical limitation of HAase. When in suspension/PEG-hydrogel and irradiated with UV light, the prepared o-NBA/HAase-HSA-NPs clearly reduced the pH of the surrounding medium to as low as 5.0 by producing protons and were better able to break down HA-based tumor cell spheroids (AsPC-1) and HA-hydrogel/microgels, presumably due to the enhanced HA activity at a more optimal pH. Moreover, when formulated as an intratumor-injectable PEG hydrogel, the o-NBA/HAase-HSA-NPs displayed significantly enhanced tumor suppression when combined with intravenous paclitaxel-loaded HSA-NPs (PTX-HSA-NPs) in AsPC-1 tumor-bearing mice: The tumor volume in mice administered UV-activated o-NBA/HAase-HSA-NPs and PTX-HSA-NPs was 198.2 ​± ​30.0 ​mm³, whereas those administered PBS or non-UV-activated o-NBA/HAase-HSA-NPs and PTX-HSA-NPs had tumor volumes of 1230.2 ​± ​256.2 and 295.4 ​± ​17.1 ​mm³, respectively. These results clearly demonstrated that when administered with paclitaxel NPs, our photoreactive o-NBA/HAase-HSA-NPs were able to reduce pH and degrade HA-based ECM, and thereby significantly suppress tumor growth. Consequently, we propose our o-NBA/HAase-HSA-NPs may be a prototype for development of future nanoparticle-based HA-ECM-depleting tumor-ablating agents.

Engineered Cytokines for Cancer and Autoimmune Disease Immunotherapy

Cytokine signaling is critical to a range of biological processes including cell development, tissue repair, aging, and immunity. In addition to acting as key signal mediators of the immune system, cytokines can also serve as potent immunotherapies with more than 20 recombinant products currently Food and Drug Administration (FDA)-approved to treat conditions including hepatitis, multiple sclerosis, arthritis, and various cancers. Yet despite their biological importance and clinical utility, cytokine immunotherapies suffer from intrinsic challenges that limit their therapeutic potential including poor circulation, systemic toxicity, and low tissue- or cell-specificity. In the past decade in particular, methods have been devised to engineer cytokines in order to overcome such challenges and here, the myriad strategies are reviewed that may be employed in order to improve the therapeutic potential of cytokine and chemokine immunotherapies with applications in cancer and autoimmune disease therapy, as well as tissue engineering and regenerative medicine. For clarity, these strategies are collected and presented as they vary across size scales, ranging from single amino acid substitutions, to larger protein-polymer conjugates, nano/micrometer-scale particles, and macroscale implants. Together, this work aims to provide readers with a timely view of the field of cytokine engineering with an emphasis on early-stage therapeutic approaches.

Dual mechanistic TRAIL nanocarrier based on PEGylated heparin taurocholate and protamine which exerts both pro-apoptotic and anti-angiogenic effects

The selective cytotoxicity of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) to cancer cells but not to normal cells makes it an attractive candidate for cancer therapeutics. However, the disadvantages of TRAIL such as physicochemical instability and short half-life limit its further clinical applications. In this study, TRAIL was encapsulated into a novel anti-angiogenic nanocomplex for both improved drug distribution at the tumor site and enhanced anti-tumor efficacy. A nanocomplex was prepared firstly by entrapping TRAIL into PEG-low molecular weight heparin-taurocholate conjugate (LHT7), which is previously known as a potent angiogenesis inhibitor. Then, protamine was added to make a stable form of nanocomplex (PEG-LHT7/TRAIL/Protamine) by exerting electrostatic interactions. We found that entrapping TRAIL into the nanocomplex significantly improved both pharmacokinetic properties and tumor accumulation rate without affecting the tumor selective cytotoxicity of TRAIL. Furthermore, the anti-tumor efficacy of nanocomplex was highly augmented (73.77±4.86%) compared to treating with only TRAIL (18.49 ± 19.75%), PEG-LHT7/Protamine (47.84 ± 14.20%) and co-injection of TRAIL and PEG-LHT7/Protamine (56.26 ± 9.98%). Histological analysis revealed that treatment with the nanocomplex showed both anti-angiogenic efficacy and homogenously induced cancer cell apoptosis, which suggests that accumulated TRAIL and LHT7 in tumor tissue exerted their anti-tumor effects synergistically. Based on this study, we suggest that PEG-LHT7/Protamine complex is an effective nanocarrier of TRAIL for enhancing drug distribution as well as improving anti-tumor efficacy by exploiting the synergistic mechanism of anti-angiogenesis.

Microbial Exopolysaccharides as Drug Carriers

Microbial exopolysaccharides are peculiar polymers that are produced by living organisms and protect them against environmental factors. These polymers are industrially recovered from the medium culture after performing a fermentative process. These materials are biocompatible and biodegradable, possessing specific and beneficial properties for biomedical drug delivery systems. They can have antitumor activity, they can produce hydrogels with different characteristics due to their molecular structure and functional groups, and they can even produce nanoparticles via a self-assembly phenomenon. This review studies the potential use of exopolysaccharides as carriers for drug delivery systems, covering their versatility and their vast possibilities to produce particles, fibers, scaffolds, hydrogels, and aerogels with different strategies and methodologies. Moreover, the main properties of exopolysaccharides are explained, providing information to achieve an adequate carrier selection depending on the final application.

Harmonious Biomaterials for Development of In situ Approaches for Locoregional Delivery of Anti-cancer Drugs: Current Trends

Locoregional drug delivery is a novel approach for the effective delivery of anti-cancer agents as it exposes the tumors to high concentration of drugs. In situ gelling systems have fetched paramount attention in the field of localized cancer chemotherapy due to their targeted delivery, ease of preparation, prolonged or sustained drug release and improved patient compliance. Numerous polymers have been investigated for their properties like swelling along with biodegradation, drug release and physicochemical properties for successful targeting of the drugs at the site of implantation. The polymers such as chitosan, Hyaluronic Acid (HA), poloxamer, Poly Glycolic Lactic Acid (PGLA) and Poly Lactic Acid (PLA) tend to form in situ hydrogels and have been exploited to develop localized delivery vehicles. These formulations are administered in the solution form and on exposure to physiological environment such as temperature, pH or ionic composition they undergo phase conversion into a hydrogel drug depot. The use of in situ gelling approach has provided prospects to increase overall survival and life quality of cancer patient by enhancing the bioavailability of drug to the site of tumor by minimizing the exposure to normal cells and alleviating systemic side effects. Because of its favorable safety profile and clinical benefits, United States Food and Drug Administration (U.S. FDA) has approved polymer based in situ systems for prolonged locoregional activity. This article discusses the rationale for developing in situ systems for targeted delivery of anti-cancer agents with special emphasis on types of polymers used to formulate the in situ system. In situ formulations for locoregional anti-cancer drug delivery that are marketed and are under clinical trials have also been discussed in detail in this article.

Development of Biocompatible HA Hydrogels Embedded with a New Synthetic Peptide Promoting Cellular Migration for Advanced Wound Care Management

In the past few years, there have been many efforts underway to develop effective wound healing treatments for traumatic injuries. In particular, wound-healing peptides (WHPs) and peptide-grafted dressings hold great promise for novel therapeutic strategies for wound management. This study reports a topical formulation of a new synthetic WHP (REGRT, REG) embedded in a hyaluronic acid (HA)-based hydrogel dressing for the enhancement of acute excisional wound repair. The copper-free click chemistry is utilized to form biocompatible HA hydrogels by cross-linking dibenzocyclooctyl-functionalized HA with 4-arm poly(ethylene glycol) (PEG) azide. The HA hydrogels are grafted with the REG peptide, a functional derivative of erythroid differentiation regulator1, displaying potent cell motility-stimulating ability, thus sustainably releasing physiologically active peptides for a prolonged period. Combined with the traditional wound healing benefits of HA, the HA hydrogel embedded REG (REG-HAgel) accelerates re-epithelialization in skin wound healing, particularly by promoting migration of fibroblasts, keratinocytes, and endothelial cells. REG-HAgels improve not only rate, but quality of wound healing with higher collagen deposition and more microvascular formation while being nontoxic. The peptide-grafted HA hydrogel system can be considered as a promising new wound dressing formulation strategy for the treatment of different types of wounds with combinations of various natural and synthetic WHPs.

Designer hydrogels: Shedding light on the physical chemistry of the pancreatic cancer microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is currently the third leading cause of cancer mortality in the United States, with a 5-year survival of ∼8%. PDAC is characterized by a dense and hypo-vascularized stroma consisting of proliferating cancer cells, cancer-associated fibroblasts, macrophages and immune cells, as well as excess matrices including collagens, fibronectin, and hyaluronic acid. In addition, PDAC has increased interstitial pressures and a hypoxic/acidic tumor microenvironment (TME) that impedes drug delivery and blocks cancer-directed immune mechanisms. In spite of increasing options in targeted therapy, PDAC has mostly remained treatment recalcitrant. Owing to its critical roles on governing PDAC progression and treatment outcome, TME and its interplay with the cancer cells are increasingly studied. In particular, three-dimensional (3D) hydrogels derived from or inspired by components in the TME are progressively developed. When properly designed, these hydrogels (e.g., Matrigel, collagen gel, hyaluronic acid-based, and semi-synthetic hydrogels) can provide pathophysiologically relevant compositions, conditions, and contexts for supporting PDAC cell fate processes. This review summarizes recent efforts in using 3D hydrogels for fundamental studies on cell-matrix or cell-cell interactions in PDAC.

Chitosan-alginate BSA-gel-capsules for local chemotherapy against drug-resistant breast cancer

BACKGROUND AND OBJECT

Polyelectrolyte microcapsule is a promising candidate for multifunctional drug delivery system. However, the lack of reports about animal experiments have greatly slowed down their development for drug delivery. We engineered biodegradable chitosan-alginate polyelectrolyte multilayer capsule filled with bovine serum albumin gel (BSA-gel-capsule). Herein, we demonstrated their applicability for local chemotherapy, a means of treating local or regional malignancies by direct administration of anti-tumor agents to tumor sites.

METHOD

Doxorubicin (DOX) was loaded in BSA-gel-capsules and DOX-resistant cell line (MCF-7/ADR cells) was employed for antitumor studies in vitro. The cytotoxicity, cellular uptake and distribution of DOX from BSA-gel-capsules were studied. Afterwards, MCF-7/ADR xenografts tumor model was established in nude mice. The in vivo antitumor efficacy of DOX-loaded BSA-gel-capsules by intratumor injection was then evaluated.

RESULT

Compared with free DOX, more effective cytotoxicity against MCF-7/ADR cells after treatment with DOX-loaded BSA-gel-capsules was revealed, demonstrating the positive reversal effect on drug-resistance. Thereafter, the more cellular uptake and nucleus distribution of DOX from BSA-gel-capsules in MCF-7/ADR cells provided convincing explanation for the reversal effect. DOX-loaded BSA-gel-capsules displayed remarkably more antitumor efficacy than free DOX in MCF-7/ADR cell-xenografted mice. Finally, the high DOX accumulation and prolonged retention in tumor site after local administration of DOX-loaded BSA-gel-capsules was demonstrated, displaying the unique advantages of BSA-gel-capsules for local chemotherapy.

CONCLUSION

These findings indicate that DOX-loaded BSA-gel-capsules should be considered a potential candidate for the treatment of drug-resistant breast cancer. This paper provides a feasibility for the local chemotherapy of polyelectrolyte microcapsules, which will be a big step towards their application as drug delivery vehicles.

Nanocarriers for TRAIL delivery: driving TRAIL back on track for cancer therapy

Since its initial identification, tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) has been shown to be capable of selectively inducing apoptosis in cancer cells. However, translation of the encouraging preclinical studies of this cytokine into the clinic has been restricted by its extremely short half-life, the presence of resistant cancer cell populations, and its inefficient in vivo delivery. Recently, there has been exceptional progress in developing novel formulations to increase the circulatory half-life of TRAIL and new combinations to treat cancers that are resistant to TRAIL. In particular, TRAIL-based nanotherapies offer the potential to improve the stability of TRAIL and prolong its half-life in plasma, to specifically deliver TRAIL to a particular target site, and to overcome resistance to TRAIL. The aim of this review is to provide an overview of the state-of-the art drug delivery systems that are currently being tested or developed to improve the biological attributes of TRAIL-based therapies.

Engineering of Micro- to Nanostructured 3D-Printed Drug-Releasing Titanium Implants for Enhanced Osseointegration and Localized Delivery of Anticancer Drugs

Primary and secondary bone cancers are major causes of pathological bone fractures which are usually treated through implant fixation and chemotherapy. However, both approaches face many limitations. On one hand, implants may suffer from poor osseointegration, and their rejection results in repeated surgery, patient's suffering, and extensive expenses. On the other hand, there are severe systemic adverse effects of toxic chemotherapeutics which are administrated systemically. In this paper, in order to address these two problems, we present a new type of localized drug-releasing titanium implants with enhanced implants' biointegration and drug release capabilities that could provide a high concentration of anticancer drugs locally to treat bone cancers. The implants are fabricated by 3D printing of Ti alloy followed by an anodization process featuring unique micro- (particles) and nanosurface (tubular arrays) topography. We successfully demonstrate their enhanced bone osseointegration and drug loading capabilities using two types of anticancer drugs, doxorubicin (DOX) and apoptosis-inducing ligand (Apo2L/TRAIL). In vitro study showed strong anticancer efficacy against cancer cells (MDA-MB-231-TXSA), confirming that these drug-releasing implants can be used for localized chemotherapy for treatment of primary and secondary bone cancers together with fracture support.

Multiple hyperthermia-mediated release of TRAIL/SPION nanocomplex from thermosensitive polymeric hydrogels for combination cancer therapy

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) possesses strong anti-cancer potential because of its ability to specifically kill cancer cells. However, clinical use of TRAIL is impeded by its short in vivo half-life and native TRIAL-resistant cancer cell populations. To overcome these limitations, we designed a multiple magnetic hyperthermia (MHT)-mediated TRAIL release system for combination therapy using an injectable, biodegradable and thermosensitive polymeric hydrogel. In this system, positively charged TRAIL and hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs) are complexed with negatively charged poly(organophosphazene) polymers via ionic and hydrophobic interactions, respectively. Transmission electron microscopy images showed a nano-sized core-shell structure of the TRAIL/SPION polymeric nanocomplex in aqueous solution that transformed into a hydrogel at body temperature. Hyperthermia can enhance the release of TRAIL from hydrogels through temperature-sensitive hydrogel dissolution. TRAIL-resistant U-87 MG cells were killed by the combination of TRAIL and multiple hyperthermia via caspase-3 and -8 active apoptosis. The hyperthermia-enhanced cytotoxicity of TRAIL was dependent on the hyperthermia cycle number and corresponding TRAIL release. Significant in vivo tumor reduction was observed by combining 2 cycles of mild MHT and TRAIL release using a single injection of TRAIL/SPION nanocomplex hydrogels without damage to main organs. Furthermore, the therapeutic outcomes can be monitored by long-term magnetic resonance imaging.

Improved antitumor activity of TRAIL fusion protein via formation of self-assembling nanoparticle

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been known as a promising agent for cancer therapy due to its specific apoptosis-inducing effect on tumor cells rather than most normal cells. However, systemically delivered TRAIL suffers from a rapid clearance from the body with an extremely short half-life. Thermally responsive elastin-like polypeptides (ELPs) are a promising class of temperature sensitive biopolymers based on the structural motif found in mammalian tropoelastin and retain the advantages of polymeric drug delivery systems. We therefore expressed RGD-TRAIL fused with ELP (RGD-TRAIL-ELP) in E. coli. Purification of RGD-TRAIL-ELP was achieved by the conveniently inverse transition cycling (ITC). The purified RGD-TRAIL-ELP without any chemical conjugation was able to self-assemble into nanoparticle under physiological condition. Non-reducing SDS-PAGE results showed that trimer content of RGD-TRAIL-ELP increased 3.4-fold than RGD-TRAIL. Flow cytometry confirmed that RGD-TRAIL-ELP 3-fold enhanced apoptosis-inducing capacity than RGD-TRAIL. Single intraperitoneal injection of the RGD-TRAIL-ELP nanoparticle induced nearly complete tumor regression in the COLO-205 tumor xenograft model. Histological observation confirmed that RGD-TRAIL-ELP induced significant tumor cell apoptosis without apparent liver toxicity. These findings suggested that a great potential application of the RGD-TRAIL-ELP nanoparticle system as a safe and efficient delivery strategy for cancer therapy.

Hyaluronic acid and its derivatives in drug delivery and imaging: Recent advances and challenges

Hyaluronic acid (HA) is a biodegradable, biocompatible, nontoxic, and non-immunogenic glycosaminoglycan used for various biomedical applications. The interaction of HA with the CD44 receptor, whose expression is elevated on the surface of many types of tumor cells, makes this polymer a promising candidate for intracellular delivery of imaging and anticancer agents exploiting a receptor-mediated active targeting strategy. Therefore, HA and its derivatives have been most investigated for the development of several carrier systems intended for cancer diagnosis and therapy. Nonetheless, different and important delivery applications of the polysaccharide have also been described, including gene and peptide/protein drugs delivery. The aim of this review was to provide an overview of the existing recent literature on the use of HA and its derivatives for drug delivery and imaging. Notable attention is given to nanotheranostic systems obtained after conjugation of HA to nanocarriers as quantum dots, carbon nanotubes and graphene. Meanwhile, attention is also paid to some challenging aspects that need to be addressed in order to allow translation of preclinical models based on HA and its derivatives for drug delivery and imaging purposes to clinical testing and further their development.

Hyaluronic acid-coated, prodrug-based nanostructured lipid carriers for enhanced pancreatic cancer therapy

CONTEXT

Gemcitabine (GEM) and Baicalein (BCL) are reported to have anti-tumor effects including pancreatic cancer. Hyaluronic acid (HA) can bind to over-expressed receptors in various kinds of cancer cells.

OBJECTIVE

The aim of this study is to develop prodrugs containing HA, BCL and GEM, and construct nanomedicine incorporate GEM and BCL in the core and HA on the surface. This system could target the cancer cells and co-deliver the drugs.

METHODS

GEM-stearic acid lipid prodrug (GEM-SA) and hyaluronic acid-amino acid-baicalein prodrug (HA-AA-BCL) were synthesized. Then, GEM and BCL prodrug-based targeted nanostructured lipid carriers (HA-GEM-BCL NLCs) were prepared by the nanoprecipitation technique. The in vitro cytotoxicity studies of the NLCs were evaluated on AsPC1 pancreatic cancer cell line. In vivo anti-tumor effects were observed on the murine-bearing pancreatic cancer model.

RESULTS

HA-GEM-BCL NLCs were effective in entering pancreatic cancer cells over-expressing HA receptors, and showed cytotoxicity of tumor cells in vitro. In vivo study revealed significant tumor growth inhibition ability of HA-GEM-BCL NLCs in murine pancreatic cancer model.

CONCLUSION

It could be concluded that HA-GEM-BCL NLCs could be featured as promising co-delivery, tumor-targeted nanomedicine for the treatment of cancers.

Hyaluronic acid for anticancer drug and nucleic acid delivery

Hyaluronic acid (HA) is widely used in anticancer drug delivery, since it is biocompatible, biodegradable, non-toxic, and non-immunogenic; moreover, HA receptors are overexpressed on many tumor cells. Exploiting this ligand-receptor interaction, the use of HA is now a rapidly-growing platform for targeting CD44-overexpressing cells, to improve anticancer therapies. The rationale underlying approaches, chemical strategies, and recent advances in the use of HA to design drug carriers for delivering anticancer agents, are reviewed. Comprehensive descriptions are given of HA-based drug conjugates, particulate carriers (micelles, liposomes, nanoparticles, microparticles), inorganic nanostructures, and hydrogels, with particular emphasis on reports of preclinical/clinical results.

Doxorubicin-loaded nanoparticles consisted of cationic- and mannose-modified-albumins for dual-targeting in brain tumors

Albumin nanoparticles have been increasingly viewed as an effective way of delivering chemotherapeutics to solid tumors. Here, we report the one-pot development of a unique prototype of doxorubicin-loaded nanoparticles (NPs) made of naïve albumin (HSA) plus cationic- (c-HSA) or mannose-modified-albumin (m-HSA), with the goal of traversing the blood-brain barrier and targeting brain tumors. c-HSA was synthesized by conjugating ethylenediamine to naïve HSA. Then, m-HSA was derivatized using mannopyranoside via a thiol-maleimide reaction. The c/m-HSA NPs were prepared using a mixture solution of c- and m-HSAs in deionized water and doxorubicin in ethanol/chloroform in the same pot using a high-pressure homogenizer. The c/m-HSA NPs were spherical and well-dispersed, with a particle size of 90.5±3.1nm and zeta-potential of -12.0±0.3mV at c- and m-HSA feed ratios of 5% and 10%, respectively. The c/m-HSA NPs displayed good stability over 3days based on particle size and a linear gradual doxorubicin release over 2days. Specifically, the inhibitory concentration (IC50; 0.5±0.02μg/ml) of c/m-HSA NPs was >2.2-15.6 fold lower than those of doxorubicin or the other HSA NPs. Moreover, among HSA NPs, c/m-HSA NPs exhibited the most prominent performances in transport across the bEnd.3 cell monolayer and uptake in bEnd.3 cells as well as U87MG glioblastoma cells and spheroids. Furthermore, c/m-HSA NPs were localized to a greater extent in brain glioma compared to naïve HSA NPs. Orthotopic glioma-bearing mice treated with c/m-HSA NPs displayed significantly smaller tumors than the mice treated with saline, doxorubicin or HSA NPs. This improved anti-glioma efficacy seemed to be due to the dual-enhanced system of dual cationic absorptive transcytosis and glucose-transport by the combined use of c- and m-HSAs. The c/m-HSA NPs have potential as a novel anti-brain cancer agent with good targetability.

Hydrogels 2.0: improved properties with nanomaterial composites for biomedical applications

The incorporation of nanomaterials in hydrogels (hydrated networks of crosslinked polymers) has emerged as a useful method for generating biomaterials with tailored functionality. With the available engineering approaches it is becoming much easier to fabricate nanocomposite hydrogels that display improved performance across an array of electrical, mechanical, and biological properties. In this review, we discuss the fundamental aspects of these materials as well as recent developments that have enabled their application. Specifically, we highlight synthesis and fabrication, and the choice of nanomaterials for multifunctionality as ways to overcome current material property limitations. In addition, we review the use of nanocomposite hydrogels within the framework of biomedical and pharmaceutical disciplines.

Doxorubicin-Bound Albumin Nanoparticles Containing a TRAIL Protein for Targeted Treatment of Colon Cancer

PURPOSE

We developed a new nanoparticle formulation comprised of human serum albumin (HSA) for co-delivery of doxorubicin (Dox) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) with the goal of apoptotic synergy in the treatment of colon cancer.

METHODS

TRAIL (0.2, 0.4, 1.0%)- and Dox-loaded HSA nanoparticles (TRAIL/Dox HSA NPs) were prepared by using the nab(TM) technology. Morphological and physicochemical characterizations were investigated by dynamic light scattering and transmission electron microscopy. Synergistic cytotoxicity, apoptotic activity, and potential penetration into mass tumor were determined in HCT116 cell-based systems. Furthermore, antitumor efficacy and tumor targeting were also investigated.

RESULTS

TRAIL/Dox HSA NPs were uniformly spherical with sizes of 60 ~ 120 nm. The encapsulation efficacy of Dox and TRAIL was 68.9-77.2% and 80.4-86.0%, respectively. TRAIL 1.0%/Dox HSA NPs displayed the best inhibition of HCT116 colon cancer cells; inhibition was 6 times higher than achieved with Dox HSA NPs. The TRAIL 1.0%/Dox HSA NPs formulation was studied further. Flow cytometry analysis and TUNEL assay revealed that TRAIL 1.0%/Dox HSA NPs had markedly greater apoptotic activity than Dox HSA NPs. In HCT116 tumor-bearing BALB/c nu/nu mice, TRAIL 1.0%/Dox HSA NPs had significantly higher antitumor efficacy than Dox HSA NPs (tumor volume; 933.4 mm(3) vs. 3183.7 mm(3), respectively). TRAIL 1.0%/Dox HSA NPs penetrated deeply into tumor masses in a HCT116 spheroid model and localized in tumor sites after tail vein injection.

CONCLUSIONS

Data indicate that TRAIL 1.0%/Dox HSA NPs offer advantages of co-delivery of Dox and TRAIL in tumors, with potential synergistic apoptosis-based anticancer therapy.

In situ facile-forming PEG cross-linked albumin hydrogels loaded with an apoptotic TRAIL protein

The key to making a practicable hydrogel for pharmaceutical or medical purposes is to endow it with relevant properties, i.e., facile fabrication, gelation time-controllability, and in situ injectability given a firm basis for safety/biocompatibility. Here, the authors describe an in situ gelling, injectable, albumin-cross-linked polyethylene glycol (PEG) hydrogel that was produced using a thiol-maleimide reaction. This hydrogel consists of two biocompatible components, namely, thiolated human serum albumin and 4-arm PEG20k-maleimide, and can be easily fabricated and gelled in situ within 60s by simply mixing its two components. In addition, the gelation time of this system is controllable in the range 15s to 5min. This hydrogel hardly interacted with an apoptotic TRAIL protein, ensuring suitable release profiles that maximize therapeutic efficacy. Specifically, tumors (volume: 278.8mm(3)) in Mia Paca-2 cell-xenografted BALB/c nu/nu mice treated with the TRAIL-loaded HSA-PEG hydrogel were markedly smaller than mice treated with the hydrogel prepared via an amine-N-hydroxysuccinimide reaction or non-treated mice (1275.5mm(3) and 1816.5mm(3), respectively). We believe that this hydrogel would be a new prototype of locally injectable sustained-release type anti-cancer agents, and furthermore offers practical convenience for a doctor and universal applicability for a variety of therapeutic proteins.

Hyaluronic acid hydrogel scaffolds with a triple degradation behavior for bone tissue engineering

In this study, in order to better mimick the nature of bone extracellular matrix, hyaluronic acid (HA) hydrogels having a triple degradation behavior were synthesized from 3,3'-dithiodipropionate hydrazide-modified HA (DTPH-HA) and polyethylene glycol dilevulinate (LEV-PEG-LEV) via the reaction of the ketone carbonyl groups of LEV-PEG-LEV with the hydrazide groups of DTPH-HA. The HA hydrogels were characterized by solid state (13)C NMR, FT-IR, SEM, and rheological, swelling and degradation tests. The results showed that the HA hydrogels exhibited a highly porous morphology and had pore diameters ranging from 20 to 200 μm. The equilibrium swelling ratio of the HA hydrogels was no less than 37.5. The HA hydrogels could be degraded by hyaluronidase and reducing substances or at acidic pH values. The biocompatibility of the HA hydrogels was evaluated using osteoblast-like MC3T3-E1 cells by live/dead staining and MTT assays. The results revealed that the HA hydrogels had good biocompatibility and could support the attachment and proliferation of MC3T3-E1 cells. All the results indicated that the HA hydrogels synthesized by hydrazone bond crosslinking might have great potential to be used in bone tissue engineering.

PEGylated apoptotic protein-loaded PLGA microspheres for cancer therapy

The aim of the current study was to investigate the antitumor potential of poly (D,L-lactic-co-glycolic acid) microspheres (PLGA MSs) containing polyethylene glycol (PEG)-conjugated (PEGylated) tumor necrosis factor–related apoptosis-inducing ligand (PEG-TRAIL). PEG-TRAIL PLGA MSs were prepared by using a water-in-oil-in-water double-emulsion method, and the apoptotic activities of supernatants released from the PLGA MSs at days 1, 3, and 7 were examined. The antitumor effect caused by PEG-TRAIL PLGA MSs was evaluated in pancreatic Mia Paca-2 cell-xenografted mice. PEG-TRAIL PLGA MS was found to be spherical and 14.4±1.06 μm in size, and its encapsulation efficiency was significantly greater than that of TRAIL MS (85.7%±4.1% vs 43.3%±10.9%, respectively). The PLGA MS gradually released PEG-TRAIL for 14 days, and the released PEG-TRAIL was shown to have clear apoptotic activity in Mia Paca-2 cells, whereas TRAIL released after 1 day had a negligible activity. Finally, PEG-TRAIL PLGA MS displayed remarkably greater antitumor efficacy than blank or TRAIL PLGA MS in Mia Paca-2 cell-xenografted mice in terms of tumor volume and weight, apparently due to increased stability and well-retained apoptotic activity of PEG-TRAIL in PLGA MS. We believe that this PLGA MS system, combined with PEG-TRAIL, should be considered a promising candidate for treating pancreatic cancer.

Opportunities for multicomponent hybrid hydrogels in biomedical applications

Hydrogels provide mechanical support and a hydrated environment that offer good cytocompatibility and controlled release of molecules, and myriad hydrogels thus have been studied for biomedical applications. In the past few decades, research in these areas has shifted increasingly to multicomponent hydrogels that better capture the multifunctional nature of native biological environments and that offer opportunities to selectively tailor materials properties. This review summarizes recent approaches aimed at producing multicomponent hydrogels, with descriptions of contemporary chemical and physical approaches for forming networks, and of the use of both synthetic and biologically derived molecules to impart desired properties. Specific multicomponent materials with enhanced mechanical properties are presented, as well as materials in which multiple biological functions are imparted for applications in tissue engineering, cancer treatment, and gene therapies. The progress in the field suggests significant promise for these approaches in the development of biomedically relevant materials.

Supramolecular hydrogels co-loaded with camptothecin and doxorubicin for sustainedly synergistic tumor therapy

A supramolecular hydrogel was prepared to encapsulate and release both camptothecin and doxorubicin in a controlled manner for sustainedly synergistic tumor therapy.