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

Polyphenol-Based Particles for Theranostics

Polyphenols, due to their high biocompatibility and wide occurrence in nature, have attracted increasing attention in the engineering of functional materials ranging from films, particles, to bulk hydrogels. Colloidal particles, such as nanogels, hollow capsules, mesoporous particles and core-shell structures, have been fabricated from polyphenols or their derivatives with a series of polymeric or biomolecular compounds through various covalent and non-covalent interactions. These particles can be designed with specific properties or functionalities, including multi-responsiveness, radical scavenging capabilities, and targeting abilities. Moreover, a range of cargos (e.g., imaging agents, anticancer drugs, therapeutic peptides or proteins, and nucleic acid fragments) can be incorporated into these particles. These cargo-loaded carriers have shown their advantages in the diagnosis and treatment of diseases, especially of cancer. In this review, we summarize the assembly of polyphenol-based particles, including polydopamine (PDA) particles, metal-phenolic network (MPN)-based particles, and polymer-phenol particles, and their potential biomedical applications in various diagnostic and therapeutic applications.

Ingredients in Zijuan Pu'er Tea Extract Alleviate β-Amyloid Peptide Toxicity in a Caenorhabditis elegans Model of Alzheimer's Disease Likely through DAF-16

Amyloid-β, one of the hallmarks of Alzheimer's disease (AD), is toxic to neurons and can also cause brain cell death. Oxidative stress is known to play an important role in AD, and there is strong evidence that oxidative stress is associated with amyloid-β. In the present study we report the protective effect of Zijuan Pu'er tea water extract (ZTWE) and the mixture of main ingredients (+)-catechins, caffeine and procyanidin (MCCP) in ZTWE on β-amyloid-induced toxicity in transgenic Caenorhabditis elegans (C. elegans) CL4176 expressing the human Aβ_1⁻42 gene. ZTWE, (+)-catechins, caffeine, procyanidin and MCCP delayed the β-amyloid-induced paralysis to different degrees. The MCCP treatment did not affect the transcript abundance of amyloid-β transgene (amy-1); however, Thioflavin T staining showed a significant decrease in Aβ accumulation compared to untreated worms. Further research using transgenic worms found that MCCP promoted the translocation of DAF-16 from cytoplasm to nucleus and increased the expression of superoxide dismutase 3 (SOD-3). In addition, MCCP decreased the reactive oxygen species (ROS) content and increased the SOD activity in CL4176 worms. In conclusion, the results suggested that MCCP had a significant protective effect on β-amyloid-induced toxicity in C. elegans by reducing β-amyloid aggregation and inducing DAF-16 nuclear translocation that could activate the downstream signal pathway and enhance resistance to oxidative stress.

Vitamin B12-conjugated sericin micelles for targeting CD320-overexpressed gastric cancer and reversing drug resistance

AIM

Our previous research has introduced sericin micelles to reverse drug resistance. However, these micelles could not selectively bind to gastric cancer (GC) cells. We developed vitamin B12 (VB12) conjugated sericin micelles for targeted GC therapy.

MATERIALS & METHODS

We used VB12, sericin, synthetic poly(γ-benzyl-L-glutamate) (PBLG) and paclitaxel (PTX) to develop VB12-conjugated and PTX-loaded micelles (VB12-sericin-PBLG-PTX). Then we explored their physicochemical properties, cellular uptake and antitumor mechanism.

RESULTS

VB12-sericin-PBLG-PTX micelles were proved to be of appropriate particle size, have good dispersion and are bio-safe. Following transcobalamin II (CD320)-receptor-mediated endocytosis, these swallowed micelles with GC-targeting and enhanced cellular uptake abilities, alter mitochondrial transmembrane potential/apoptosis pathway and reverse drug resistance.

CONCLUSION

VB12-sericin-PBLG-PTX micelles are promising materials for GC-targeted clinical applications.

DOX-assisted functionalization of green tea polyphenol nanoparticles for effective chemo-photothermal cancer therapy

Green tea polyphenol nanoparticles with chemotherapeutic and photothermal performance exhibited effective anti-tumor effects in vivo with intravenous injection.

Self-assembly of porphyrin-grafted lipid into nanoparticles encapsulating doxorubicin for synergistic chemo-photodynamic therapy and fluorescence imaging

The limited clinical efficacy of monotherapies in the clinic has urged the development of novel combination platforms. Taking advantage of light-triggered photodynamic treatment combined together with the controlled release of nanomedicine, it has been possible to treat cancer without eliciting any adverse effects. However, the challenges imposed by limited drug loading capacity and complex synthesis process of organic nanoparticles (NPs) have seriously impeded advances in chemo-photodynamic combination therapy. In this experiment, we utilize our previously synthesized porphyrin-grafted lipid (PGL) NPs to load highly effective chemotherapeutic drug, doxorubicin (DOX) for synergistic chemo-photodynamic therapy.

Methods: A relatively simple and inexpensive rapid injection method was used to prepare porphyrin-grafted lipid (PGL) NPs. The self-assembled PGL NPs were used further to encapsulate DOX via a pH-gradient loading protocol. The self-assembled liposome-like PGL NPs having a hydrophilic core were optimized to load DOX at an encapsulation efficiency (EE) of ~99%. The resultant PGL-DOX NPs were intact, highly stable and importantly these NPs successfully escaped from the endo-lysosomal compartment after laser irradiation to release DOX in the cytosol. The therapeutic efficacy of the aforementioned formulation was validated both in vitro and in vivo.

Results: PGL-DOX NPs demonstrated excellent cellular uptake, chemo-photodynamic response, and fluorescence imaging ability in different cell lines. Under laser irradiation, cells treated with a low molar concentration of PGL-DOX NPs reduced cell viability significantly. Moreover, in vivo experiments conducted in a xenograft mouse model further demonstrated the excellent tumor accumulation capability of PGL-DOX NPs driven by the enhanced permeability and retention (EPR) effect. Through fluorescence imaging, the biodistribution of PGL-DOX NPs in tumor and major organs was also easily monitored in real time in vivo. The inherent ability of porphyrin to generate ROS under laser irradiation combined with the cytotoxic effect of the anticancer drug DOX significantly suppressed tumor growth in vivo.

Conclusion: In summary, the PGL-DOX NPs combined chemo-photodynamic nanoplatform may serve as a potential candidate for cancer theranostics.

Design, Synthesis, and Characterization of Schiff Base Bond-Linked pH-Responsive Doxorubicin Prodrug Based on Functionalized mPEG-PCL for Targeted Cancer Therapy

The side effects of doxorubicin (DOX) extremely limit its application in the treatment of malignant tumors. Nano-sized polymeric drugs based on the acidic microenvironment of tissular- or intra- tumor have attracted ample attention because of their potential in reducing side effects. In this research, an amphiphilic diblock copolymer based on poly (ethylene glycol) (PEG) and functionalized polycaprolactone (PCL) was synthesized and utilized as the drug carrier. DOX was chemically conjugated with the polymer via acid-cleavable imine bonds to obtain a novel pH-sensitive DOX prodrug (mPEG-PCL-Imi-DOX). mPEG-PCL-Imi-DOX (24.2 wt % DOX content) formed micelles with an average diameter of 125 nm through a simple solvent evaporation method. The in vitro release profile demonstrated that DOX release of the prodrug micelles was pH-responsive and able to be accelerated with the decrease of pH. In vitro cytotoxicity assay tests revealed that the pH-sensitive DOX prodrug micelles exhibited relatively lower toxicity and similar antitumor efficacy towards MCF-7 cells compared with free DOX. Hence, the DOX prodrug micelles with imine bonds can offer a carrier with great potential for chemo-therapeutics.

Rational design of multimodal therapeutic nanosystems for effective inhibition of tumor growth and metastasis

Simultaneous inhibition of both tumor growth and metastasis is the key to treating metastatic cancer, yet the development of effective drug delivery systems represents a great challenge since multimodal therapeutic agents must be rationally combined to overcome the biological mechanisms underpinning tumor cell proliferation and invasion. In this context, we report a hybrid therapeutic nanoscale platform that incorporates an anti-proliferative drug, doxorubicin (DOX), and an anti-NF-κB agent, p65-shRNA, for effective treatment of metastatic breast cancer. In our design, we first conjugated DOX via an acid-labile linker onto gold nanorods that were pre-modified with the tumor targeting peptide RGD and a positively charged, disulfide cross-linked short polyethylenimines (DSPEI), and then incorporated shRNA through electrostatic complexation with DSPEI. We show that this "all in one" nanotherapeutic system (RDG/shRNA@DOX) can be effectively internalized through RGD-mediated endocytosis, followed by stimuli-responsive intracellular co-release of DOX and shRNA. Our in vitro experiments suggest that this multimodal system can significantly inhibit cell proliferation, angiogenesis, and invasion of metastatic MDA-MB-435 cancer cells. Systemic administration of RDG/shRNA@DOX into a metastatic mouse model led to enhanced tumor accumulation, and, most importantly, significant inhibition of in situ tumor growth and almost complete suppression of tumor metastasis. We believe this hybrid multimodal nanotherapeutic system provides important insight into the rational design of therapeutic systems for the effective treatment of metastatic carcinoma.

STATEMENT OF SIGNIFICANCE

The key to successfully treat metastatic cancer is the simultaneous inhibition of both tumor growth and metastasis. This represents a great challenge for the design of drug delivery systems since multimodal therapeutic agents must be rationally combined to overcome the respective biological mechanisms underpinning tumor cell proliferation and invasion. Toward this end, we developed a hybrid nanomedicine platform that incorporates an anti-proliferative drug, doxorubicin (DOX), and an anti-NF-κB agent, p65-shRNA, for effective treatment of metastatic breast cancer. We showed that this multimodal system (RDG/shRNA@DOX) enhanced tumor accumulation, led to prolonged circulation, and most importantly, significant inhibition of in situ tumor growth and almost complete suppression of tumor metastasis. We believe this hybrid multimodal nanotherapeutic system provides significant insight into the rational design of therapeutic systems for the effective treatment of metastatic cancer.

Sialic-Acid-Anchored Micelles: A Hierarchical Targeting Device for Enhanced Tumor Tissue Accumulation and Cellular Internalization

Targeted drug delivery systems (TDDS) have attracted wide attention for their reduced drug side effects and improved antitumor efficacy in comparison with traditional preparations. While targeting moieties in existing TDDS have principally focused on recognition of receptors on the surface of tumor cells, accumulation into tumor tissue only could be performed by enhanced permeability and retention effects and active transportation into tumor cells. Doxorubicin (DOX)-loaded sialic acid-dextran (Dex)-octadecanoic acid (OA) micelles (SA-Dex-OA/DOX) were designed for targeting hepatocellular carcinoma effectively. The synthesized conjugates could self-aggregate to form micelles with a critical micelle concentration of 27.6 μg·mL^-1 and diameter of 54.53 ± 3.23 nm. SA-Dex-OA micelles incorporated with 4.36% DOX-loading content could prolong in vitro drug release to 96 h with 80% of final release. Cellular transportation studies revealed that SA-Dex-OA micelles mediated more efficient DOX delivery into Bel-7402 cells than those without SA modification. In vivo biodistribution testing demonstrated that SA-Dex-OA/ICG micelles showed 3.05-fold higher accumulation into Bel-7402 tumors. The recognition of overexpressed E-selectin in inflammatory tumor vascular endothelial cells led to a large accumulation of SA-Dex-OA/ICG micelles into tumor tissue, and the E-selectin upregulated on the surface of tumor cells contributed to active cellular transportation into tumor cells. Accordingly, SA-Dex-OA/DOX exhibited prior suppression of Bel-7402 tumor growth greater than that of Dex-OA/DOX micelles and free DOX (the tumor inhibition: 79.2% vs 61.0 and 51.3%). These results suggest that SA-functionalized micelles with dual targeting properties have high potential for liver cancer therapy.

Highly Augmented Drug Loading and Stability of Micellar Nanocomplexes Composed of Doxorubicin and Poly(ethylene glycol)-Green Tea Catechin Conjugate for Cancer Therapy

Low drug loading and instability in blood circulation are two key challenges that impede the successful clinical translation of nanomedicine, as they result in only marginal therapeutic efficacy and toxic side effects associated with premature drug leakage, respectively. Herein, highly stable and ultrahigh drug loading micellar nanocomplexes (MNCs) based on the self-assembly of the anticancer drug doxorubicin (DOX) and a poly(ethylene glycol)-epigallocatechin-3-O-gallate (EGCG) conjugate are developed. The formation of these MNCs is facilitated by strong favorable intermolecular interactions between the structurally similar aromatic EGCG and DOX molecules, which impart exceptionally high drug-loading capability of up to 88% and excellent thermodynamic and kinetic stability. Unlike two clinical formulations of DOX-free DOX and liposomal DOX, which are not effective below their lethal dosages, these DOX-loaded MNCs demonstrate significant tumor growth inhibition in vivo on a human liver cancer xenograft mouse model with minimal unwanted toxicity. Overall, these MNCs can represent a safe and effective strategy to deliver DOX for cancer therapy.

E. coli Nissle 1917-Derived Minicells for Targeted Delivery of Chemotherapeutic Drug to Hypoxic Regions for Cancer Therapy

Purpose: Systemic administration of free chemotherapeutic drugs leads to severe toxic effects, and physiological characteristics of solid tumors restrain the drugs from reaching the hypoxic regions. E. coli Nissle 1917 (EcN) has been known to penetrate the barrier and proliferate in the interface between the viable and necrotic regions of tumors. This study aimed to fabricate a nanoscale minicell via genetic engineering of EcN for targeted delivery of chemotherapeutic drugs to the hypoxic regions of tumors for cancer therapy. Methods: A large number of minicells were produced by knocking out the minCD gene and enhancing the minE expression in EcN. Then, a pH (low) insertion peptide (pHLIP) was displayed on the membrane surface through protein display technology to endow the cells with the ability to target the acidic microenvironments of tumors. The acidic-microenvironment targeting ability and therapeutic effect of the engineered minicells with chemotherapeutic drugs was thoroughly evaluated by using breast cancer cells and an orthotopic model of breast tumor. Results: The EcN-derived minicells displaying pHLIP could be directly extracted from the fermentation broth and used for delivering chemotherapeutic drugs without any further modification. Targeting of doxorubicin (DOX)-loaded minicells to cancer cells via pHLIP resulted in rapid internalization and drug release in acidic media. Importantly, the pHLIP-mosaic minicells successfully invaded the necrotic and hypoxic regions of orthotopic breast cancers where free chemotherapeutic drugs could never get to because of vascular insufficiency and high interstitial fluid pressure. This invasion resulted in significant regression of an orthotopic breast tumor in a mouse model, while no seriously pathogenic effects were observed during the animal experiments. Conclusions: This study provides a novel strategy for the fabrication of tumor-targeting carriers via genetic engineering based on biomaterials with the ability to penetrate hypoxic regions of tumors, high biocompatibility and low toxicity.

Size-controlled, colloidally stable and functional nanoparticles based on the molecular assembly of green tea polyphenols and keratins for cancer therapy

Molecular assembly of green tea polyphenols and keratins into size-controlled, colloidally stable and functional nanoparticles for enhanced cancer therapy was achieved.

Polymerization-induced self-assembly of large-scale iohexol nanoparticles as contrast agents for X-ray computed tomography imaging

Fundamental research for CT imaging, in which iohexol nanoparticles (INPs) were synthesised using a one-pot strategy via polymerization-induced self-assembly (PISA).

Indomethacin-based stimuli-responsive micelles combined with paclitaxel to overcome multidrug resistance

Development of multidrug resistance against antitumor agents is a major limiting factor for the successful chemotherapy. Currently, both amphiphilic polymeric micelles and chemosensitizers have been proposed to overcome MDR during chemotherapy. Herein, the redox-responsive polymeric micelles composed of dextran and indomethacin (as chemosensitizer) using a disulfide bond as the linker are prepared (DEX-SS-IND) for delivery of antitumor agent paclitaxel (PTX). The high level of glutathione in tumor cells selectively breaks the disulfide bond, leading to the rapid breakdown and deformation of redox-responsive polymeric micelles. The data show that DEX-SS-IND can spontaneously form the stable micelles with high loading content (9.48 ± 0.41%), a favorable size of 45 nm with a narrow polydispersity (0.157), good stability, and glutathione-triggered drug release behavior due to the rapid breakdown of disulfide bond between DEX and IND. In vitro antitumor assay shows DEX-SS-IND/PTX micelles effectively inhibit the proliferation of PTX-resistant breast cancer (MCF-7/PTX) cells. More impressively, DEX-SS-IND/PTX micelles possess the improved plasma pharmacokinetics, enhanced antitumor efficacy on tumor growth in the xenograft models of MCF-7/PTX cells, and better in vivo safety. Overall, DEX-SS-IND/PTX micelles display a great potential for cancer treatment, especially for multidrug resistance tumors.

Nanocapsules for the co-delivery of selol and doxorubicin to breast adenocarcinoma 4T1 cells in vitro

Nanocapsules (NCS-DOX) with an oily core of selol and a shell of poly(methyl vinyl ether-co-maleic anhydride) covalently conjugated to doxorubicin were developed. These nanocapsules are spherical, with an average hydrodynamic diameter of about 170 nm, and with negative zeta potential. NCS-DOX effectively co-delivered the selol and the doxorubicin into 4T1 cells and changed the intracellular distribution of DOX from the nuclei to the mitochondria. Moreover, a significantly increased cytotoxicity against 4T1 cells was observed, which is suggestive of additive or synergic effect of selol and doxorubicin. In conclusion, PVM/MA nanocapsules are suitable platforms to co-deliver drugs into cancer cells.

Doxorubicin synergism and resistance reversal in human neuroblastoma BE(2)C cell lines: An in vitro study with dextran-catechin nanohybrids

Hybrid nanocarrier consisting in nanographene oxide coated by a dextran-catechin conjugate was proposed in the efforts to find more efficient Neuroblastoma treatment with Doxorubicin chemotherapy. The dextran-catechin conjugate was prepared by immobilized laccase catalysis and its peculiar reducing ability exploited for the synthesis of the hybrid carrier. Raman spectra and DSC thermograms were recorded to check the physicochemical properties of the nanohybrid, while DLS measurements, SEM, TEM, and AFM microscopy allowed the determination of its morphological and dimensional features. A pH dependent Doxorubicin release was observed, with 30 and 75% doxorubicin released at pH 7.4 and 5.0, respectively. Viability assays on parental BE(2)C and resistant BE(2)C/ADR cell lines proved that the high anticancer activity of dextran-catechin conjugate (IC₅₀ 19.9 ± 0.6 and 18.4 ± 0.7 µg mL^-1) was retained upon formation of the nanohybrids (IC₅₀ 24.8 ± 0.7 and 22.9 ± 1 µg mL^-1). Combination therapy showed a synergistic activity between doxorubicin and either bioconjugate or nanocarrier on BE(2)C. More interestingly, on BE(2)C/ADR we recorded both the reversion of doxorubicin resistance mechanism as a consequence of decreased P-gp expression (Western Blot analysis) and a synergistic effect on cell viability, confirming the proposed nanohybrid as a very promising starting point for further research in neuroblastoma treatment.

Ginsenoside Rg3 micelles mitigate doxorubicin-induced cardiotoxicity and enhance its anticancer efficacy

Doxorubicin (DOX) is one of the most effective chemotherapy agents used in the treatment of hematological and solid tumors, however, it causes dose-related cardiotoxicity that may lead to heart failure in patients. One of the major reasons was increased reactive oxygen species (ROS) production. Ginsenoside Rg3 (Rg3), was powerful free radical scavengers and possessed cardioprotective effects. Nevertheless, Rg3 has low aqueous solubility and oral bioavailability, limiting its effects. Herein, we encapsulated Rg3 through spontaneous self-assembly of Pluronic F127 to improve its solubility and oral bioavailability. Moreover, co-administering Rg3 in Pluronic F127 micelles with doxorubicin can mitigate the cardiotoxicity, with ameliorating mitochondrial and metabolic function, improving calcium handling, and decreasing ROS production. In addition, it can improve the anticancer efficacy of doxorubicin. Therefore, our study provides a rational strategy for further developing a potentially viable adjunct-supportive treatment for reducing toxicity and increasing efficiency on chemotherapy.

Temperature-Sensitive Gold Nanoparticle-Coated Pluronic-PLL Nanoparticles for Drug Delivery and Chemo-Photothermal Therapy

Gold nanoparticle-coated Pluronic-b-poly(L-lysine) nanoparticles (Pluronic-PLL@Au NPs) were synthesized via an easy one-step method and employed as carriers for the delivery of paclitaxel (PTX) in chemo-photothermal therapy, in which Pluronic-PLL acts as the reductant for the formation of AuNPs without the need for an additional reducing agent.

METHODS

The deposition of AuNPs on the surface of Pluronic-PLL micelles and the thermal response of the system were followed via ultraviolet-visible spectroscopy and dynamic light scattering. Calcein-AM and MTT assays were used to study the cell viability of MDA-MB-231 cells treated with PTX-loaded Pluronic-PLL@Au NPs, and we then irradiated the cells with NIR light.

RESULTS

An obvious temperature response was observed for the Pluronic-PLL@Au NPs. Blood compatibility and in vitro cytotoxicity assays confirmed that the Pluronic-PLL@Au NPs have excellent biocompatibility. Compared to Taxol, the PTX-loaded Pluronic-PLL@Au NPs exhibited higher cytotoxicity in MDA-MB-231 cells. All of these results and confocal laser scanning microscopy analysis results suggest that Pluronic-PLL@Au NPs greatly enhance the cellular uptake efficiency of the drug.

CONCLUSION

As confirmed by in vitro and in vivo studies, the combination of chemotherapy and photothermal therapy can cause more damage than chemo- or photothermal therapy did alone, demonstrating the synergistic effect of chemo-photothermal treatment. Thus, the as-prepared Pluronic-PLL@Au NPs are promising for chemo-photothermal therapy.

Catechin ameliorates doxorubicin-induced neuronal cytotoxicity in in vitro and episodic memory deficit in in vivo in Wistar rats

Cognitive dysfunction by chemotherapy compromises the quality of life in cancer patients. Tea polyphenols are known chemopreventive agents. The present study was designed to evaluate the neuroprotective potential of (+) catechin hydrate (catechin), a tea polyphenol, in IMR-32 neuroblastoma cells in vitro and alleviation of episodic memory deficit in Wistar rats in vivo against a widely used chemotherapeutic agent, Doxorubicin (DOX). In vitro, neuroprotective studies were assessed in undifferentiated IMR-32 cells using percentage viability and in differentiated cells by neurite length. These studies showed catechin increased percentage viability of undifferentiated IMR-32 cells. Catechin pretreatment also showed an increase in neurite length of differentiated cells. In vivo neuroprotection of catechin was evaluated using novel object recognition task in time-induced memory deficit model at 50, 100 and 200 mg/kg dose and DOX-induced memory deficit models at 100 mg/kg dose. The latter model was developed by injection of DOX (2.5 mg/kg, i.p.) in 10 cycles over 50 days in Wistar rats. Catechin showed a significant reversal of time-induced memory deficit in a dose-dependent manner and prevention of DOX-induced memory deficit at 100 mg/kg. In addition, catechin treatment showed a significant decrease in oxidative stress, acetylcholine esterase and neuroinflammation in the hippocampus and cerebral cortex in DOX-induced toxicity model. Hence, catechin may be a potential adjuvant therapy for the amelioration of DOX-induced cognitive impairment which may improve the quality of life of cancer survivors. This improvement might be due to the elevation of antioxidant defense, prevention of neuroinflammation and inhibition of acetylcholine esterase enzyme.

Doxorubicin-loaded redox-responsive micelles based on dextran and indomethacin for resistant breast cancer

Multidrug resistance (MDR) against chemotherapeutic agents has become one of the major obstacles to successful cancer therapy and MDR-associated proteins (MRPs)-mediated drug efflux is the key factor for MDR. In this study, a redox-responsive polymer based on dextran (DEX) and indomethacin (IND), which could reduce MRPs-mediated efflux of chemotherapeutics, was synthesized, and the obtained polymer could spontaneously form stable micelles with well-defined core-shell structure and a uniform size distribution with an average diameter of 50 nm and effectively encapsulate doxorubicin (DOX); the micelles contain a disulfide bridge (cystamine, SS) between IND and DEX (DEX-SS-IND). In vitro drug release results indicated that DEX-SS-IND/DOX micelles could maintain good stability in a stimulated normal physiological environment and promptly depolymerized and released DOX in a reducing environment. After incubating DEX-SS-IND/DOX micelles with drug-resistant tumor (MCF-7/ADR) cells, the intracellular accumulation and retention of DOX were significantly increased under the synergistic effects of redox-responsive delivery and the inhibitory effect of IND on MRPs. In vitro cytotoxicity showed that DEX-SS-IND/DOX micelles exhibited higher cytotoxicity against MCF-7/ADR cells. Moreover, DEX-SS-IND/DOX micelles showed significantly enhanced inhibition of tumor in BALB/c nude mice bearing MCF-7/ADR tumors and reduced systemic toxicity. Overall, the cumulative evidence indicates that DEX-SS-IND/DOX micelles hold significant promise for overcoming MDR for cancer therapy.

Chemosensitizing indomethacin-conjugated dextran-based micelles for effective delivery of paclitaxel in resistant breast cancer therapy

Multidrug resistance (MDR) against chemotherapeutic agents has become the major obstacle to successful cancer therapy and multidrug resistance-associated proteins (MRPs) mediated drug efflux is the key factor for MDR. Indomethacin (IND), one of the non-steroidal anti-inflammatory agents, has been demonstrated to increase cytotoxic effects of anti-tumor agents as MRP substrates. In this study, dextran-g-indomethacin (DEX-IND) polymeric micelles were designed to delivery paclitaxel (PTX) for the treatment of MDR tumors. The DEX-IND polymer could effectively encapsulate PTX with high loading content and DEX-IND/PTX micelles present a small size distribution. Compared with free PTX, the release of PTX from DEX-IND/PTX micelles could be prolonged to 48 h. Cellular uptake test showed that the internalization of DEX-IND/PTX micelles by drug-sensitive MCF-7/ADR cells was significantly higher than free PTX benefiting from the inhibitory effect of IND on MRPs. In vitro cytotoxicity test further demonstrated that DEX-IND/PTX micelles could enhance the cytotoxicity of PTX against MCF-7/ADR tumor cells. In vivo pharmacokinetic results showed that DEX-IND/PTX micelles had longer systemic circulation time and slower plasma elimination rate in comparison to PTX. The anti-tumor efficacy test showed that DEX-IND/PTX micelles exhibited greater tumor growth-inhibition effects on MDR tumor-bearing mice, with good correlation between in vitro and in vivo. Overall, the cumulative evidence indicates that DEX-IND/PTX micelles hold significant promise for the treatment of MDR tumors.

Targeted Chemo-Photodynamic Combination Platform Based on the DOX Prodrug Nanoparticles for Enhanced Cancer Therapy

Chemo-photodynamic combination therapy has been received widespread attention in cancer treatment due to its excellent characteristics, such as reducing the adverse side effects of chemo-drugs and improving the therapeutic effects for various cancers. In this study, RGD and DOX was conjugated to PEG by thiol-ene addition and Schiff's base reaction, respectively, to prepare the targeted and pH-sensitive antitumor prodrug nanoparticles (RGD-PEG-DOX NPs, RGD-NPs). Subsequently, the photosensitizer chlorin e6 (Ce6) was encapsulated into RGD-NPs, thus obtaining a simple and efficient chemo-photodynamic combination platform (RGD-PEG-DOX/Ce6 NPs, RGD-NPs/Ce6). This nanoparticle possessed high drug loading property of both the chemo-drug and photosensitizer and could simultaneously release them under the mild acidic microenvironment of cancer cells, which was expected to realize the synchronization therapy of chemotherapy and photodynamic therapy (PDT). Compared with free DOX and Ce6, RGD-NPs/Ce6 could significantly improve the cellular uptake capacities of DOX and Ce6, resulting in the increased contents of ROS in cancer cells and effective cytotoxicity for tumor cells (MDA-MB-231 cells and MCF-7 cells) upon a laser radiation. The in vivo experiment showed that RGD-NPs/Ce6 displayed superior tumor targeting, accumulation, and retention ability than the other groups (free DOX, free Ce6 and NPs/Ce6), and thus significantly enhancing the antitumor effect in vivo with a laser radiation. In addition, the cardiotoxicity induced by DOX was thoroughly wiped out after being loaded and delivered by the nanoparticles according to the pathological analysis. Therefore, the targeted chemo-photodynamic combination therapeutic platform may be a promising candidate for enhanced cancer therapy.

Gold nanorod-based poly(lactic-co-glycolic acid) with manganese dioxide core-shell structured multifunctional nanoplatform for cancer theranostic applications

Recently, photothermal therapy has become a promising strategy in tumor treatment. However, the therapeutic effect was seriously hampered by the low tissue penetration of laser. Therefore, in this study, radiofrequency (RF) with better tissue penetration was used for tumor hyperthermia. First, one type of gold nanorods (AuNRs) suitable for RF hyperthermia was selected. Then, poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with AuNRs and docetaxel (DTX) (PLGA/AuNR/DTX) NPs were constructed. Finally, manganese dioxide (MnO2) ultrathin nanofilms were coated on the surfaces of PLGA/AuNR/DTX NPs by the reduction of KMnO4 to construct the PLGA/AuNR/DTX@MnO2 drug delivery system. This drug delivery system can not only be used for the combined therapy of chemotherapy and RF hyperthermia but can also produce Mn2+ to enable magnetic resonance imaging. Furthermore, the RF hyperthermia and the degradation of MnO2 can significantly promote the controlled drug release in a tumor region. The in vitro and in vivo results suggested that the PLGA/AuNR/DTX@MnO2 multifunctional drug delivery system is a promising nanoplatform for effective cancer theranostic applications.

Phosphorylcholine-based stealthy nanocapsules enabling tumor microenvironment-responsive doxorubicin release for tumor suppression

The efficient delivery of anticancer drugs into tumor tissues to improve therapeutic efficacy remains an urgent demand. To satisfy this demand, a drug delivery system based on a stealthy nanocapsule was developed. This nanocapsule was fabricated by encapsulating stealthy cross-linked poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and benzaldehyde groups around the protein bovine serum albumin (BSA) followed by conjugation of doxorubicin (Dox) through a pH-responsive benzoic-imine bond. The in vitro results show that the Dox-conjugated nanocapsule (nBSA-Dox) released the drug under an acidic tumor microenvironment (pH ~6.5) and killed HepG2 human liver cancer cells. The half-life of Dox conjugated to nBSA in mice was significantly prolonged, and the area-under-curve of plasma Dox of the mice treated with nBSA-Dox was as much as 242 fold of free Dox. The in vivo results confirmed that this nanocapsule efficiently accumulated in tumor tissue and significantly suppressed the tumor growth.

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.

Anti‑proliferative activity of epigallocatechin‑3‑gallate and silibinin on soft tissue sarcoma cells

Disseminated soft tissue sarcomas (STS) present a therapeutic dilemma. The first-line cytostatic doxorubicin demonstrates a response rate of 30% and is not suitable for elderly patients with underlying cardiac disease, due to its cardiotoxicity. Well‑tolerated alternative treatment options, particularly in palliative situations, are rare. Therefore, the present study assessed the anti‑proliferative effects of the natural compounds epigallocatechin-3-gallate (EGCG), silibinin and noscapine on STS cells. A total of eight different human STS cell lines were used in the study: Fibrosarcoma (HT1080), liposarcoma (SW872, T778 and MLS‑402), synovial sarcoma (SW982, SYO1 and 1273) and pleomorphic sarcoma (U2197). Cell proliferation and viability were analysed by 5‑bromo-2'-deoxyuridine and MTT assays and real‑time cell analysis (RTCA). RTCA indicated that noscapine did not exhibit any inhibitory effects. By contrast, EGCG decreased proliferation and viability of all cell lines except for the 1273 synovial sarcoma cell line. Silibinin exhibited anti‑proliferative effects on all synovial sarcoma, liposarcoma and fibrosarcoma cell lines. Liposarcoma cell lines responded particularly well to EGCG while synovial sarcoma cell lines were more sensitive to silibinin. In conclusion, the green tea polyphenol EGCG and the natural flavonoid silibinin from milk thistle suppressed the proliferation and viability of liposarcoma, synovial sarcoma and fibrosarcoma cells. These compounds are therefore potential candidates as mild therapeutic options for patients that are not suitable for doxorubicin‑based chemotherapy and require palliative treatment. The findings from the present study provide evidence to support in vivo trials assessing the effect of these natural compounds on solid sarcomas.

Nanostructure-Based Theranostic Systems

This themed issue continues the focus on the recent developments of nanoscaled theranostic systems for early and accurate disease diagnosis, especially cancer diagnosis, as well as effective cancer treatment and management.