Self-assembled micellar nanocomplexes comprising green tea catechin derivatives and protein drugs for cancer therapy

Phenolic compounds based conjugates from dextran aldehyde and BSA: Preparation, characterization and evaluation of their anti-cancer efficacy for therapeutic applications

Here, we have synthesized phenolic compounds (pc) based on conjugates from dextran aldehyde (dex-ald) and bovine serum albumin (BSA) and screening their potential activity as therapeutic agents in cancer disease. The synthesized conjugates were analyzed by UV-vis, FT-IR, XRD and SEM analysis. UV-vis spectra of conjugates showed the shifting of spectral peak at UV to visible region revealed the enhanced conjugation due to formation of linkage. The XRD peaks of conjugates found broader and indicating the amorphous phase of conjugating materials in compared to free components. The SEM images showed that the conjugated materials having numerous pores on its surface, which proved its porous nature. The amount of phenolic compounds conjugated with (dex-ald-pc) and (BSA-pc) were found to be 65.4 and 73.91mg/g of conjugates, respectively. Cells viability was significantly decreased approximately 80-85% at concentration of 100μg conjugates whereas the free polymers or phenolics did not affect the viability of cancer cells. Generation of high quantity of reactive oxygen species (ROS) in cells treated with conjugate materials, which may caused cell apoptosis in cancer cell line. The results clearly showed that conjugation of phenolic compounds were an effective method to improve the functional properties for therapeutic applications.

A new molecular mechanism underlying the EGCG-mediated autophagic modulation of AFP in HepG2 cells

Epigallocatechingallate (EGCG) is a major bioactive component of green tea and is associated with health benefits against multiple diseases including cancer. As an indicator of hepatocellular carcinoma (HCC), high levels of α-fetal protein (AFP) are related to malignant differentiation and poor prognosis of cancer cells. In this study, EGCG can effectively reduce AFP secretion and simultaneously induce AFP aggregation in human HCC HepG₂ cells. EGCG-stimulated autophagy induces the degradation of AFP aggregates in HepG₂ cells. Furthermore, we thoroughly studied the underlying molecular mechanisms behind EGCG-stimulated autophagy by using large-scale all-atom molecular dynamics simulations, which revealed a novel molecular mechanism. EGCG directly interacts with LC3-I protein, readily exposing the pivotal Gly-120 site of the latter to other important binding partners such as 1,2-distearoyl-sn-glycero-3-phosphoethanolamine and promoting the synthesis of LC3-II, a characteristic autophagosomal marker. Our results suggest that EGCG is critical in regulating AFP secretion and in modulating autophagic activities of HepG₂ cells, providing a molecular basis for potentially preventing and treating HCC.

Active Antioxidizing Particles for On-Demand Pressure-Driven Molecular Release

Overproduced reactive oxygen species (ROS) are closely related to various health problems including inflammation, infection, and cancer. Abnormally high ROS levels can cause serious oxidative damage to biomolecules, cells, and tissues. A series of nano- or microsized particles has been developed to reduce the oxidative stress level by delivering antioxidant drugs. However, most systems are often plagued by slow molecular discharge, driven by diffusion. Herein, this study demonstrates the polymeric particles whose internal pressure can increase upon exposure to H₂O₂, one of the ROS, and in turn, discharge antioxidants actively. The on-demand pressurized particles are assembled by simultaneously encapsulating water-dispersible manganese oxide (MnO₂) nanosheets and green tea derived epigallocatechin gallate (EGCG) molecules into a poly(lactic-co-glycolic acid) (PLGA) spherical shell. In the presence of H₂O₂, the MnO₂ nanosheets in the PLGA particle generate oxygen gas by decomposing H₂O₂ and increase the internal pressure. The pressurized PLGA particles release antioxidative EGCG actively and, in turn, protect vascular and brain tissues from oxidative damage more effectively than the particles without MnO₂ nanosheets. This H₂O₂ responsive, self-pressurizing particle system would be useful to deliver a wide array of molecular cargos in response to the oxidation level.

pH-Responsive Nanoscale Coordination Polymer for Efficient Drug Delivery and Real-Time Release Monitoring

Both excess dosages of drug and unwanted drug carrier can lead to severe side effects as well as the failure of tumor therapy. Here, an Fe³⁺ -gallic acid based drug delivery system is designed for efficient monitoring of drug release in tumor. Fe³⁺ and polyphenol gallic acid can form polygonal nanoscale coordination polymer in aqueous solution, which exhibits certain antitumor effect. Importantly, this coordination polymer possesses extremely high doxorubicin (DOX) loading efficacy (up to 48.3%). In vitro studies demonstrate that the fluorescence of DOX can be quenched efficiently when DOX is loaded on the coordination polymer. The acidity in lysosome also triggers the release of DOX and fluorescence recovery simultaneously, which realizes real-time monitoring of drug release in tumor cells. In vivo studies further indicate that this polyphenol-rich drug delivery system can significantly inhibit tumor growth with negligible heart toxicity of DOX. This system with minimal side effects should be a promising nanoplatform for tumor treatment.

Modulation of oncogenic transcription factors by bioactive natural products in breast cancer

Carcinogenesis, a multi-step phenomenon, characterized by alterations at genetic level and affecting the main intracellular pathways controlling cell growth and development. There are growing number of evidences linking oncogenes to the induction of malignancies, especially breast cancer. Modulations of oncogenes lead to gain-of-function signals in the cells and contribute to the tumorigenic phenotype. These signals yield a large number of proteins that cause cell growth and inhibit apoptosis. Transcription factors such as STAT, p53, NF-κB, c-JUN and FOXM1, are proteins that are conserved among species, accumulate in the nucleus, bind to DNA and regulate the specific genes targets. Oncogenic transcription factors resulting from the mutation or overexpression following aberrant gene expression relay the signals in the nucleus and disrupt the transcription pattern. Activation of oncogenic transcription factors is associated with control of cell cycle, apoptosis, migration and cell differentiation. Among different cancer types, breast cancer is one of top ten cancers worldwide. There are different subtypes of breast cancer cell-lines such as non-aggressive MCF-7 and aggressive and metastatic MDA-MB-231 cells, which are identified with distinct molecular profile and different levels of oncogenic transcription factor. For instance, MDA-MB-231 carries mutated and overexpressed p53 with its abnormal, uncontrolled downstream signalling pathway that account for resistance to several anticancer drugs compared to MCF-7 cells with wild-type p53. Appropriate enough, inhibition of oncogenic transcription factors has become a potential target in discovery and development of anti-tumour drugs against breast cancer. Plants produce diverse amount of organic metabolites. Universally, these metabolites with biological activities are known as "natural products". The chemical structure and function of natural products have been studied since 1850s. Investigating these properties leaded to recognition of their molecular effects as anticancer drugs. Numerous natural products extracted from plants, fruits, mushrooms and mycelia, show potential inhibitory effects against several oncogenic transcription factors in breast cancer. Natural compounds that target oncogenic transcription factors have increased the number of candidate therapeutic agents. This review summarizes the current findings of natural products in targeting specific oncogenic transcription factors in breast cancer.

Evolution and Clinical Translation of Drug Delivery Nanomaterials

With the advent of technology, the role of nanomaterials in medicine has grown exponentially in the last few decades. The main advantage of such materials has been exploited in drug delivery applications, due to their effective targeting that in turn reduces systemic toxicity compared to the conventional routes of drug administration. Even though these materials offer broad flexibility based on targeting tissue, disease, and drug payload, the demand for more effective yet highly biocompatible nanomaterial-based drugs is increasing. While therapeutically improved and safe materials have been introduced in nanomedicine platforms, issues related to their degradation rates and bio-distribution still exist, thus making their successful translation for human use very challenging. Researchers are constantly improving upon novel nanomaterials that are safer and more effective not only as therapeutic agents but as diagnostic tools as well, making the research in the field of nanomedicine ever more fascinating. In this review stress has been made on the evolution of nanomaterials that have been approved for clinical applications by the United States Food and Drug Administration Agency (FDA).

Self-Assembled Nanoparticles from Phenolic Derivatives for Cancer Therapy

Therapeutic nanoparticles hold clinical promise for cancer treatment by avoiding limitations of conventional pharmaceuticals. Herein, a facile and rapid method is introduced to assemble poly(ethylene glycol) (PEG)-modified Pt prodrug nanocomplexes through metal-polyphenol complexation and combined with emulsification, which results in ≈100 nm diameter nanoparticles (PtP NPs) that exhibit high drug loading (0.15 fg Pt per nanoparticle) and low fouling properties. The PtP NPs are characterized for potential use as cancer therapeutics. Mass cytometry is used to quantify uptake of the nanoparticles and the drug concentration in individual cells in vitro. The PtP NPs have long circulation times, with an elimination half-life of ≈18 h in healthy mice. The in vivo antitumor activity of the PtP NPs is systematically investigated in a human prostate cancer xenograft mouse model. Mice treated with the PtP NPs demonstrate four times better inhibition of tumor growth than either free prodrug or cisplatin. This study presents a promising strategy to prepare therapeutic nanoparticles for biomedical applications.

pH-Responsive de-PEGylated nanoparticles based on triphenylphosphine-quercetin self-assemblies for mitochondria-targeted cancer therapy

We have developed mitochondria-targeted self-assembled nanoparticles (NPs) based on amphiphilic triphenylphosphine-quercetin (TPP-Que) conjugates, which were further modified by poly(ethylene glycol) via a pH-responsive coordination bond to form TQ-PEG NPs. And it is revealed that the TQ-PEG NPs were more effective therapeutic agents compared with Que in vitro and in vivo.

EGFR and CD44 Dual-Targeted Multifunctional Hyaluronic Acid Nanogels Boost Protein Delivery to Ovarian and Breast Cancers In Vitro and In Vivo

Protein drugs with intracellular targets like Granzyme B (GrB) have demonstrated great proliferative inhibition activity in cancer cells. Their clinical translation, however, relies on the development of safe, efficient, and selective protein-delivery vehicles. Here, we report that epidermal growth factor receptor (EGFR) and CD44 dual-targeted multifunctional hyaluronic acid nanogels (EGFR/CD44-NGs) boost protein delivery to ovarian and breast cancers in vitro and in vivo. EGFR/CD44-NGs obtained via nanoprecipitation and photoclick chemistry from hyaluronic acid derivatives with tetrazole, GE11 peptide/tetrazole, and cystamine methacrylate groups had nearly quantitative loading of therapeutic proteins like cytochrome C (CC) and GrB, a small size of ca. 165 nm, excellent stability in serum, and fast protein release under a reductive condition. Flow cytometry assays showed that EGFR/CD44-NGs exhibited over 6-fold better uptake in CD44 and EGFR-positive SKOV-3 ovarian cancer cells than CD44-NGs. In accordance, GrB-loaded EGFR/CD44-NGs (GrB-EGFR/CD44-NGs) displayed enhanced caspase activity and growth inhibition in SKOV-3 cells as compared to GrB-loaded CD44-NGs (GrB-CD44-NGs) control. Intriguingly, the therapeutic studies in SKOV-3 human ovarian carcinoma and MDA-MB-231 human breast tumor xenografted in nude mice revealed that GrB-EGFR/CD44-NGs at a low dose of 3.85 nmol GrB equiv/kg induced nearly complete growth suppression of both tumors, which was obviously more effective than GrB-CD44-NGs, without causing any adverse effects. EGFR and CD44 dual-targeted multifunctional hyaluronic acid nanogels have appeared as a safe and efficacious platform for cancer protein therapy.

Polyphenol-Inspired Facile Construction of Smart Assemblies for ATP- and pH-Responsive Tumor MR/Optical Imaging and Photothermal Therapy

Smart assemblies have attracted increased interest in various areas, especially in developing novel stimuli-responsive theranostics. Herein, commercially available, natural tannic acid (TA) and iron oxide nanoparticles (Fe₃ O₄ NPs) are utilized as models to construct smart magnetic assemblies based on polyphenol-inspired NPs-phenolic self-assembly between NPs and TA. Interestingly, the magnetic assemblies can be specially disassembled by adenosine triphosphate, which shows a stronger affinity to Fe₃ O₄ NPs than that of TA and partly replaces the surface coordinated TA. The disassembly can further be facilitated by the acidic environment hence causing the remarkable change of the transverse relaxivity and potent "turn-on" of fluorescence (FL) signals. Therefore, the assemblies for specific and sensitive tumor magnetic resonance and FL dual-modal imaging and photothermal therapy after intravenous injection of the assemblies are successfully employed. This work not only provides understandings on the self-assembly between NPs and polyphenols, but also will open new insights for facilely constructing versatile assemblies and extending their biomedical applications.

Therapeutic PEG-ceramide nanomicelles synergize with salinomycin to target both liver cancer cells and cancer stem cells

AIM

Salinomycin (SAL)-loaded PEG-ceramide nanomicelles (SCM) were prepared to target both liver cancer cells and cancer stem cells.

MATERIALS & METHODS

The synergistic ratio of SAL/PEG-ceramide was evaluated to prepare SCM, and the antitumor activity of SCM was examined both in vitro and in vivo.

RESULTS

SAL/PEG-ceramide molar ratio of 1:4 was chosen as the synergistic ratio, and SCM showed superior cytotoxic effect and increased apoptosis-inducing activity in both liver cancer cells and cancer stem cells. In vivo, SCM showed the best tumor inhibitory effect with a safety profile.

CONCLUSION

Thus, PEG-ceramide nanomicelles could serve as an effective and safe therapeutic drug carrier to deliver SAL into liver cancer, opening up the avenue of using PEG-ceramide as therapeutic drug carriers.

Functional nanoparticles of tea polyphenols for doxorubicin delivery in cancer treatment

Simply-prepared nanoparticles of tea polyphenols are biocompatible, stimuli-responsive carriers for therapeutic agents, resulting in enhanced anticancer efficacy.

Tannic acid-mediated surface functionalization of polymeric nanoparticles

Polymeric nanoparticles (NPs) are decorated with various types of molecules to control their functions and interactions with specific cells. We previously used polydopamine (pD) to prime-coat poly(lactic-co-glycolic acid) (PLGA) NPs and conjugated functional ligands onto the NPs via the pD coating. In this study, we report tannic acid (TA) as an alternative prime coating that is functionally comparable to pD but does not have drawbacks of pD such as optical properties and interference of ligand characterization. TA forms a stable and optically inert coating on PLGA NPs, which can accommodate albumin, chitosan, and folate-terminated polyethylene glycol to control the cell-NP interactions. Moreover, TA coating allows for surface loading of polycyclic planar aromatic compounds. TA is a promising reactive intermediate for surface functionalization of polymeric NPs.

Hyaluronic Acid/PLGA Core/Shell Fiber Matrices Loaded with EGCG Beneficial to Diabetic Wound Healing

During the last few decades, considerable research on diabetic wound healing strategies has been performed, but complete diabetic wound healing remains an unsolved problem, which constitutes an enormous biomedical burden. Herein, hyaluronic acid (HA)/poly(lactic-co-glycolic acid, PLGA) core/shell fiber matrices loaded with epigallocatechin-3-O-gallate (EGCG) (HA/PLGA-E) are fabricated by coaxial electrospinning. HA/PLGA-E core/shell fiber matrices are composed of randomly-oriented sub-micrometer fibers and have a 3D porous network structure. EGCG is uniformly dispersed in the shell and sustainedly released from the matrices in a stepwise manner by controlled diffusion and PLGA degradation over four weeks. EGCG does not adversely affect the thermomechanical properties of HA/PLGA-E matrices. The number of human dermal fibroblasts attached on HA/PLGA-E matrices is appreciably higher than that on HA/PLGA counterparts, while their proliferation is steadily retained on HA/PLGA-E matrices. The wound healing activity of HA/PLGA-E matrices is evaluated in streptozotocin-induced diabetic rats. After two weeks of surgical treatment, the wound areas are significantly reduced by the coverage with HA/PLGA-E matrices resulting from enhanced re-epithelialization/neovascularization and increased collagen deposition, compared with no treatment or HA/PLGA. In conclusion, the HA/PLGA-E matrices can be potentially exploited to craft strategies for the acceleration of diabetic wound healing and skin regeneration.

In Vitro and in Vivo Mechanism of Bone Tumor Inhibition by Selenium-Doped Bone Mineral Nanoparticles

Biocompatible tissue-borne crystalline nanoparticles releasing anticancer therapeutic inorganic elements are intriguing therapeutics holding the promise for both tissue repair and cancer therapy. However, how the therapeutic inorganic elements released from the lattice of such nanoparticles induce tumor inhibition remains unclear. Here we use selenium-doped hydroxyapatite nanoparticles (Se-HANs), which could potentially fill the bone defect generated from bone tumor removal while killing residual tumor cells, as an example to study the mechanism by which selenium released from the lattice of Se-HANs induces apoptosis of bone cancer cells in vitro and inhibits the growth of bone tumors in vivo. We found that Se-HANs induced apoptosis of tumor cells by an inherent caspase-dependent apoptosis pathway synergistically orchestrated with the generation of reactive oxygen species. Such mechanism was further validated by in vivo animal evaluation in which Se-HANs tremendously induced tumor apoptosis to inhibit tumor growth while reducing systemic toxicity. Our work proposes a feasible paradigm toward the design of tissue-repairing inorganic nanoparticles that bear therapeutic ions in the lattice and can release them in vivo for inhibiting tumor formation.

Renal Clearable Organic Nanocarriers for Bioimaging and Drug Delivery

Renally cleared zwitterionic nanocarriers (H-Dots) are composed of ε-polylysine backbone for charge variations, near-infrared fluorophores for bioimaging, and β-cyclodextrins for potential drug delivery. H-Dots show ideal systemic circulation and rapid distribution and excrete from normal tissue/organ via renal excretion after complete targeting to the tumor site without nonspecific uptake by the immune system.

Mitochondria-Targeted Chimeric Peptide for Trinitarian Overcoming of Drug Resistance

In this report, an amphiphilic mitochondria-targeted chimeric peptide-based drug delivery system (DDS) was designed to overcome drug resistance. In vitro studies revealed that chimeric peptide could encapsulate doxorubicin (DOX) with high efficacy and target tumor mitochondria, realizing controlled release of DOX and in situ photodynamic therapy (PDT) in mitochondria. Importantly, reactive oxygen species (ROS) during PDT significantly disrupted mitochondria, leading to a dramatic decrease of intracellular adenosine 5'-triphophate (ATP). As a result, ATP-dependent efflux of DOX was remarkably inhibited. Trinitarian therapeutic strategy was developed to ablation of drug-resistant cells, that is, (1) enhanced cellular uptake of hydrophobic DOX via encapsulation in DDS, (2) combined chemo-/photodynamic therapies, and (3) suppressed generation of intracellular ATP as well as drug efflux via in situ PDT in mitochondria. This trinitarian strategy may open a new window in the fabrication of subcellular organelle destructive DDS in overcoming drug resistance.

Carbon-Dot-Decorated Carbon Nitride Nanoparticles for Enhanced Photodynamic Therapy against Hypoxic Tumor via Water Splitting

Hypoxia, a typical feature of solid tumors, remarkably restricts the efficiency of photodynamic therapy (PDT). Here, a carbon nitride (C3N4)-based multifunctional nanocomposite (PCCN) for light-driven water splitting was used to solve this problem. Carbon dots were first doped with C3N4 to enhance its red region absorption because red light could be used to trigger the in vivo water splitting process. Then, a polymer containing a protoporphyrin photosensitizer, a polyethylene glycol segment, and a targeting Arg-Gly-Asp motif was synthesized and introduced to carbon-dot-doped C3N4 nanoparticles. In vitro study showed that PCCN, thus obtained, could increase the intracellular O2 concentration and improve the reactive oxygen species generation in both hypoxic and normoxic environments upon light irradiation. Cell viability assay demonstrated that PCCN fully reversed the hypoxia-triggered PDT resistance, presenting a satisfactory growth inhibition of cancer cells in an O2 concentration of 1%. In vivo experiments also indicated that PCCN had superior ability to overcome tumor hypoxia. The use of water splitting materials exhibited great potential to improve the intratumoral oxygen level and ultimately reverse the hypoxia-triggered PDT resistance and tumor metastasis.

Cancer-Targeted Nanotheranostics: Recent Advances and Perspectives

Cancer-targeted nanotechnology is experiencing the trend of finding new materials with multiple functions for imaging and therapeutic applications. With the rapid development of the related fields, there exists a large number of reports regarding theranostic nanomedicine, decreasing the gap between cancer diagnosis and treatment with minimized separate comprehensions. In order to present an overview on the cancer-targeted nanotheranostics, we first describe their essential building blocks, including platforms, therapeutic agents and imaging agents, and then the recently rapidly developed multimodal theranostic systems. Finally we discuss the major challenges and the perspectives of future development of nanotheranostics toward clinical translations and personalized nanomedicine.

Redox-Sensitive and Intrinsically Fluorescent Photoclick Hyaluronic Acid Nanogels for Traceable and Targeted Delivery of Cytochrome c to Breast Tumor in Mice

In spite of their high specificity and potency, few protein therapeutics are applied in clinical cancer therapy owing to a lack of safe and efficacious delivery systems. Here, we report that redox-sensitive and intrinsically fluorescent photoclick hyaluronic acid nanogels (HA-NGs) show highly efficient loading and breast tumor-targeted delivery of cytochrome c (CC). HA-NGs were obtained from hyaluronic acid-graft-oligo(ethylene glycol)-tetrazole (HA-OEG-Tet) via inverse nanoprecipitation and catalyst-free photoclick cross-linking with l-cystine dimethacrylamide (MA-Cys-MA). HA-NGs exhibited a superb CC loading content of up to 40.6 wt %, intrinsic fluorescence (λem = 510 nm), and a small size of ca. 170 nm. Notably, CC-loaded nanogels (CC-NGs) showed a fast glutathione-responsive protein release behavior. Importantly, released CC maintained its bioactivity. MTT assays revealed that CC-NGs were highly potent with a low IC50 of 3.07 μM to CD44+ MCF-7 human breast tumor cells. Confocal microscopy observed efficient and selective internalization of fluorescent HA-NGs into MCF-7 cells. Interestingly, HA-NGs exhibited also effective breast tumor penetration. The therapeutic results demonstrated that CC-NGs effectively inhibited the growth of MCF-7 breast tumor xenografts at a particularly low dose of 80 or 160 nmol CC equiv./kg. Moreover, CC-NGs did not cause any change in mice body weight, corroborating their low systemic side effects. Redox-sensitive and intrinsically fluorescent photoclick hyaluronic acid nanogels have appeared as a "smart" protein delivery nanoplatform enabling safe, efficacious, traceable, and targeted cancer protein therapy in vivo.

Efficient Inhibition of Protein Aggregation, Disintegration of Aggregates, and Lowering of Cytotoxicity by Green Tea Polyphenol-Based Self-Assembled Polymer Nanoparticles

Green tea polyphenol epigallocatechin-3-gallate (EGCG) is known for its antiamyloidogenic property, and it is observed that molecular EGCG binds with amyloid structure, redirects fibrillation kinetics, remodels mature fibril, and lowers the amyloid-derived toxicity. However, this unique property of EGCG is difficult to utilize because of their poor chemical stability and substandard bioavailability. Here we report a nanoparticle form of EGCG of 25 nm size (nano-EGCG) which is 10-100 times more efficient than molecular EGCG in inhibiting protein aggregation, disintegrating mature protein aggregates, and lowering amyloidogenic cytotoxicity. The most attractive advantage of nano-EGCG is that it efficiently protects neuronal cells from the toxic effect of extracellular amyloid beta or intracellular mutant huntingtin protein aggregates by preventing their aggregation. We found that the better performance of nano-EGCG is due to the combined effect of increased chemical stability of EGCG against degradation, stronger binding with protein aggregates, and efficient entry into the cell for interaction with aggregated protein structure. This result indicates that the nanoparticle form of antiamyloidogenic molecules can be more powerful in prevention and curing of protein aggregation derived diseases.

Emerging hydrogel designs for controlled protein delivery

Hydrogels have evolved into indispensable biomaterials in the fields of drug delivery and regenerative medicine. This minireview aims to highlight the recent advances in the hydrogel design for controlled release of bioactive proteins. The latest developments of enzyme-responsive and externally regulated drug delivery systems are summarized. The design strategies and applications of phase-separated hydrogel systems are also described. We expect that these emerging approaches will enable expanded use of hydrogels in biomedicine and healthcare.

Interfacial Cohesion and Assembly of Bioadhesive Molecules for Design of Long-Term Stable Hydrophobic Nanodrugs toward Effective Anticancer Therapy

The majority of anticancer drugs are poorly water-soluble and thus suffer from rather low bioavailability. Although a variety of delivery carriers have been developed for bioavailability improvement, they are severely limited by low drug loading and undesired side effects. The optimum delivery vehicle would be a biocompatible and biodegradable drug nanoparticle of uniform size with a thin but stable shell, making it soluble, preventing aggregation and enabling targeting. Here, we present a general strategy for the rational design of hydrophobic drug nanoparticles with high drug loading by means of interfacial cohesion and supramolecular assembly of bioadhesive species. We demonstrate that the pathway is capable of effectively suppressing and retarding Ostwald ripening, providing drug nanoparticles with small and uniform size and long-term colloidal stability. The final complex drug nanoparticles provide higher tumor accumulation, negligible toxicity, and enhanced antitumor activity, superior to commercial formulations. Our findings demonstrate that local, on-demand coating of hydrophobic nanoparticles is achievable through cooperation and compromise of interfacial adhesion and assembly.

Biophysical characteristics of proteins and living cells exposed to the green tea polyphenol epigallocatechin-3-gallate (EGCg): review of recent advances from molecular mechanisms to nanomedicine and clinical trials

Herbs and traditional medicines have been applied for thousands of years, but researchers started to study their mode of action at the molecular, cellular and tissue levels only recently. Nowadays, just like in ancient times, natural compounds are still determining factors in remedies. To support this statement, the recently won Nobel Prize for an anti-malaria agent from the plant sweet wormwood, which had been used to effectively treat the disease, could be mentioned. Among natural compounds and traditional Chinese medicines, the green tea polyphenol epigallocatechin gallate (EGCg) is one of the most studied active substances. In the present review, we summarize the molecular scale interactions of proteins and EGCg with special focus on its limited stability and antioxidant properties. We outline the observed biophysical effects of EGCg on various cell lines and cultures. The alteration of cell adhesion, motility, migration, stiffness, apoptosis, proliferation as well as the different impacts on normal and cancer cells are all reviewed. We also handle the works performed using animal models, microbes and clinical trials. Novel ways to develop its utilization for therapeutic purposes in the future are discussed too, for instance, using nanoparticles and green tea polyphenols together to cure illnesses and the combination of EGCg and anticancer compounds to intensify their effects. The limitations of the employed experimental models and criticisms of the interpretation of the obtained experimental data are summarized as well.

Green Tea Catechin-Based Complex Micelles Combined with Doxorubicin to Overcome Cardiotoxicity and Multidrug Resistance

Chemotherapy for cancer treatment has been demonstrated to cause some side effects on healthy tissues and multidrug resistance of the tumor cells, which greatly limits therapeutic efficacy. To address these limitations and achieve better therapeutic efficacy, combination therapy based on nanoparticle platforms provides a promising approach through delivering different agents simultaneously to the same destination with synergistic effect. In this study, a novel green tea catechin-based polyion complex (PIC) micelle loaded with doxorubicin (DOX) and (-)-Epigallocatechin-3-O-gallate (EGCG) was constructed through electrostatic interaction and phenylboronic acid-catechol interaction between poly(ethylene glycol)-block-poly(lysine-co-lysine-phenylboronic acid) (PEG-PLys/PBA) and EGCG. DOX was co-loaded in the PIC micelles through π-π stacking interaction with EGCG. The phenylboronic acid-catechol interaction endowed the PIC micelles with high stability under physiological condition. Moreover, acid cleavability of phenylboronic acid-catechol interaction in the micelle core has significant benefits for delivering EGCG and DOX to same destination with synergistic effects. In addition, benefiting from the oxygen free radicals scavenging activity of EGCG, combination therapy with EGCG and DOX in the micelle core could protect the cardiomyocytes from DOX-mediated cardiotoxicity according to the histopathologic analysis of hearts. Attributed to modulation of EGCG on P-glycoprotein (P-gp) activity, this kind of PIC micelles could effectively reverse multidrug resistance of cancer cells. These results suggested that EGCG based PIC micelles could effectively overcome DOX induced cardiotoxicity and multidrug resistance.

Carrier-Free, Chemophotodynamic Dual Nanodrugs via Self-Assembly for Synergistic Antitumor Therapy

There are tremendous challenges from both tumor and its therapeutic formulations affecting the effective treatment of tumor, including tumor recurrence, and complex multistep preparations of formulation. To address these issues, herein a simple and green approach based on the self-assembly of therapeutic agents including a photosensitizer (chlorine e6, Ce6) and a chemotherapeutic agent (doxorubicin, DOX) was developed to prepare carrier-free nanoparticles (NPs) with the ability to inhibit tumor recurrence. The designed NPs were formed by self-assembly of Ce6 and DOX associated with electrostatic, π-π stacking and hydrophobic interactions. They have a relatively uniform size of average 70 nm, surface charge of -20 mV and high drug encapsulation efficiency, which benefits the favorable accumulation of drugs at the tumor region through a potential enhanced permeability and retention (EPR) effect as compared to their counterpart of free Ce6 solution. In addition, they could eradiate tumors without recurrence in a synergistic way following one treatment cycle. Furthermore, the NPs are safe without any activation of inflammation or immune response in separated organs. Taken together, the rationale of these pure nanodrugs via the self-assembly approach might open an alternative avenue and give inspiration to fabricate new carrier-free nanodrugs for tumor theranostics, especially for two small molecular antitumor drugs with the aim of combinational antitumor therapy in a synergistic way.

Microneedles Integrated with Pancreatic Cells and Synthetic Glucose-Signal Amplifiers for Smart Insulin Delivery

An innovative microneedle (MN)-based cell therapy is developed for glucose-responsive regulation of the insulin secretion from exogenous pancreatic β-cells without implantation. One MN patch can quickly reduce the blood-sugar levels (BGLs) of chemically induced type-1 diabetic mice and stabilize BGLs at a reduced level for over 10 h.

Melanin nanoparticles derived from a homology of medicine and food for sentinel lymph node mapping and photothermal in vivo cancer therapy

The use of non-toxic or low toxicity materials exhibiting dual functionality for use in sentinel lymph node (SLN) mapping and cancer therapy has attracted considerable attention during the past two decades. Herein, we report that the natural black sesame melanin (BSM) extracted from black sesame seeds (Sesamum indicum L.) shows exciting potential for SLN mapping and cancer photothermal therapy. Aqueous solutions of BSM under neutral and alkaline conditions can assemble into sheet-like nanoparticles ranging from 20 to 200 nm in size. The BSM nanoparticles were encapsulated by liposomes to improve their water solubility and the encapsulated and bare BSM nanoparticles were both non-toxic to cells. Furthermore, the liposome-encapsulated BSM nanoparticles (liposome-BSM) did not exhibit any long-term toxicity in mice. The liposome-BSM nanoparticles were subsequently used to passively target healthy and tumor-bearing mice SLNs, which were identified by the black color of the nanoparticles. BSM also strongly absorbed light in the near-infrared (NIR) range, which was rapidly converted to heat energy. Human esophagus carcinoma cells (Eca-109) were killed efficiently by liposome-BSM nanocomposites upon NIR laser irradiation. Furthermore, mouse tumor tissues grown from Eca-109 cells were seriously damaged by the photothermal effects of the liposome-BSM nanocomposites, with significant tumor growth suppression compared with controls. Given that BSM is a safe and nutritious biomaterial that can be easily obtained from black sesame seed, the results presented herein represent an important development in the use of natural biomaterials for clinical SLN mapping and cancer therapy.

Targeted intracellular protein delivery based on hyaluronic acid-green tea catechin nanogels

A novel ternary nanogel based on the self-assembly of hyaluronic acid-epigallocatechin gallate conjugates (HA-EGCG), linear polyethylenimine (PEI) and Granzyme B (GzmB) in an aqueous environment was developed for the targeted intracellular delivery of GzmB into cancer cells. Lysozyme-encapsulated HA-EGCG nanogels were first prepared and characterized. HA-EGCG nanogels exhibited smaller particle sizes and a more homogeneous size distribution than the HA counterpart. Fluorescence quenching and lysozyme activity studies revealed that EGCG moieties facilitated protein binding through physical interactions and led to the formation of stable nanogels. When CD44-overexpressing HCT-116 colon cancer cells were treated with GzmB-encapsulated HA-EGCG nanogels in vitro, a significant cytotoxic effect was observed. Caspase assays and intracellular trafficking studies confirmed that cell death was due to apoptosis triggered by the delivery of GzmB to the cytosol of those cells. In comparison, little cytotoxic effect was observed in CD44-deficient cells treated with GzmB-encapsulated HA-EGCG nanogels. This study highlights the potential utility of HA-EGCG as effective intracellular protein carriers for targeted cancer therapy.

STATEMENT OF SIGNIFICANCE

Intracellularly activated cytotoxic proteins can be used to kill cancer cells but viable carriers for such proteins are lacking. In this work, we developed novel nanogels based on selfassembly of hyaluronic acid (HA)-(-)-epigallocatechin-3-gallate (EGCG) conjugates, linear polyethylenemine (PEI) and the cytotoxic protein Granzyme B (GzmB) for the intracellular delivery of GzmB for cancer therapy. HA was exploited for its ability to target CD44 which are overexpressed in many types of cancer cells, while EGCG, the main component of green tea catechins, was chosen for its ability to bind to proteins. Characterization studies showed that EGCG facilitated protein complexation through physical interactions and led to the formation of stable nanogels. HA-EGCG nanogels were able to achieve CD44 targeted killing of HCT-116 cancer cells by delivering GzmB into the cytosol of these cells. We believe that the applications of the HA-EGCG nanogels can be expanded to the intracellular delivery of other cytotoxic protein drugs for cancer therapy.

Self-assembled ternary complexes stabilized with hyaluronic acid-green tea catechin conjugates for targeted gene delivery

Nanosized polyelectrolyte complexes are attractive delivery vehicles for the transfer of therapeutic genes to diseased cells. Here we report the application of self-assembled ternary complexes constructed with plasmid DNA, branched polyethylenimine and hyaluronic acid-green tea catechin conjugates for targeted gene delivery. These conjugates not only stabilize plasmid DNA/polyethylenimine complexes via the strong DNA-binding affinity of green tea catechin, but also facilitate their transport into CD44-overexpressing cells via receptor-mediated endocytosis. The hydrodynamic size, surface charge and physical stability of the complexes are characterized. We demonstrate that the stabilized ternary complexes display enhanced resistance to nuclease attack and polyanion-induced dissociation. Moreover, the ternary complexes can efficiently transfect the difficult-to-transfect HCT-116 colon cancer cell line even in serum-supplemented media due to their enhanced stability and CD44-targeting ability. Confocal microscopic analysis demonstrates that the stabilized ternary complexes are able to promote the nuclear transport of plasmid DNA more effectively than binary complexes and hyaluronic acid-coated ternary complexes. The present study suggests that the ternary complexes stabilized with hyaluronic acid-green tea catechin conjugates can be widely utilized for CD44-targeted delivery of nucleic acid-based therapeutics.

EGCG in Green Tea Induces Aggregation of HMGB1 Protein through Large Conformational Changes with Polarized Charge Redistribution

As a major effective component in green tea, (-)-epigallocatechin-3-gallate (EGCG)'s potential benefits to human health have been widely investigated. Recent experimental evidences indicate that EGCG can induce the aggregation of HMGB1 protein, a late mediator of inflammation, which subsequently stimulates the autophagic degradation and thus provides protection from lethal endotoxemia and sepsis. In this study, we use molecular dynamics (MD) simulations to explore the underlying molecular mechanism of this aggregation of HMGB1 facilitated by EGCG. Our simulation results reveal that EGCG firmly binds to HMGB1 near Cys106, which supports previous preliminary experimental evidence. A large HMGB1 conformational change is observed, where Box A and Box B, two homogenous domains of HMGB1, are repositioned and packed together by EGCG. This new HMGB1 conformation has large molecular polarity and distinctive electrostatic potential surface. We suggest that the highly polarized charge distribution leads to the aggregation of HMGB1, which differs from the previous hypothesis that two HMGB1 monomers are linked by the dimer of EGCG. Possible aggregating modes have also been investigated with potential of mean force (PMF) calculations. Finally, we conclude that the conformation induced by EGCG is more aggregation-prone with higher binding free energies as compared to those without EGCG.

Programmed Nanococktail for Intracellular Cascade Reaction Regulating Self-Synergistic Tumor Targeting Therapy

In this work, a ZnO based nanococktail with programmed functions is designed and synthesized for self-synergistic tumor targeting therapy. The nanococktail can actively target tumors via specific interaction of hyaluronic acid (HA) with CD44 receptors and respond to HAase-rich tumor microenvironment to induce intracellular cascade reaction for controlled therapy. The exposed cell-penetrating peptide (R8) potentiates the cellular uptake of therapeutic nanoparticles into targeted tumor cells. Then ZnO cocktail will readily degrade in acidic endo/lysosomes and induce the production of desired reactive oxygen species (ROS) in situ. The destructive ROS not only leads to serious cell damage but also triggers the on-demand drug release for precise chemotherapy, thus achieving enhanced antitumor efficiency synergistically. After tail vein injection of ZnO cocktail, a favorable tumor apoptosis rate (71.2 ± 8.2%) is detected, which is significantly superior to that of free drug, doxorubicin (12.9 ± 5.2%). Both in vitro and in vivo studies demonstrate that the tailor-made ZnO cocktail with favorable biocompatibility, promising tumor specificity, and self-synergistically therapeutic capacity opens new avenues for cancer therapy.

Zero-order release of polyphenolic drugs from dynamic, hydrogen-bonded LBL films

Drug carriers capable of releasing drugs at a constant rate, or following zero-order kinetics, can lead to the best control of plasma drug concentration. Here we demonstrated that zero-order release of polyphenolic drugs, including tannic acid, epigallocatechin gallate, proanthocyanidins, and theaflavin-3'-gallate, could be achieved using hydrogen-bonded layer-by-layer films as the drug carrier. The films were fabricated using the polyphenolic drugs as hydrogen donors and polyethylene glycol (PEG) as the hydrogen acceptor. Because the drugs and PEG are bonded with reversible, dynamic hydrogen bonds, the films disintegrate gradually in aqueous solutions, and thus release the drugs into the media. Furthermore, because the PEG polymers have a narrow molecular weight distribution, the films disintegrate and release the polyphenolic drugs at a constant rate. Besides allowing for zero-order release, the drug carrier developed here also provides various ways to tune the drug release rate. The drug release rate increases with decreasing molecular weight of PEG. More importantly, the release rate could be tuned using external stimuli. Increasing the pH or temperature results in accelerated drug release, while the addition of salt retards the drug release.

PEG-derivatized octacosanol as micellar carrier for paclitaxel delivery

In this study, PEG-derivatized octacosanol copolymer was successfully developed to improve the anti-tumor activity and eliminate toxicity of the commercial formulation of paclitaxel (PTX). MPEG2K-C28, the conjugation of monomethoxy Poly(ethylene glycol) 2000 and octacosanol, was readily soluble in aqueous solution and self-assembled to form micelles with small sizes (< 20 nm) that are efficient in encapsulating PTX with a drug loading of 9.38 ± 0.18% and an encapsulation efficiency of 93.90 ± 2.12%. Meanwhile, octacosanol is very safe for humans and amazingly exhibits antitumor activity through inhibition activity of matrix metalloproteinases (MMPs) and translocation of the transcription factor (nuclear factor-kappa B, NF-κB) to the nucleus, which may be able to promote synergistic effects with PTX. A sustained and slower in vitro release behavior was observed in the (PTX micelles) than that of Taxol. PTX micelles exhibited more potent cytotoxicity than Taxol in the 4T1 breast cancer cell line. More interestingly, MPEG2K-C28 selectively inhibited the growth of 4T1 cells rather than the normal cells (HEK293 and L929 cell lines), indicating the antitumor activity of octacosanol remained after conjugation with MPEG. Acute toxicity evaluations indicated that MPEG2K-C28 was a safe drug carrier. Pharmacokinetic study revealed that PTX micelles improved the T1/2 and AUC of PTX (compared with Taxol) from 1.910 ± 0.139 h and 13.999 ± 1.109 mg/l × h to 2.876 ± 0.532 h and 76.462 ± 8.619 mg/l × h in vivo, respectively. The maximal tolerated dose (MTD) for PTX micelles (ca. 120 mg PTX/kg) in mice was significantly higher than that for Taxol (ca. 20mg PTX/kg). PTX micelles exhibited slightly better antitumor activity than Taxol but safer in 4T1 breast cancer model in vivo. The cell apoptosis in the immunofluorescent studies and the cell proliferation in the immunohistochemical studies also proved the results. In conclusion, MPEG2K-C28 is a simple, safe and effective drug delivery carrier for PTX, and has some therapeutic effects in 4T1 cells in vitro. PTX micelles showed significant antitumor activity in vivo with low systemic toxicity in 4T1 breast cancer. MPEG2K-C28 micelles entrapping PTX deserve more studies in the future.

Enhancing the therapeutic effects of polyphenols with macromolecules

A review of key macromolecular systems employed to stabilise polyphenols, including direct polymerisation of polyphenol monomers and conjugation with macromolecules.