To overcome the P-glycoprotein (P-gp)-induced multidrug resistance (MDR) of cancer cells, a novel copolymer, chitosan-graft-d-α-tocopheryl polyethylene glycol 1000 (TPGS) (CT) was synthesized for doxorubicin (DOX) delivery by the P-gp inhibiting virtue of TPGS. DOX-loaded CT nanoparticles (NPs) were fabricated by a modified solvent extraction/evaporation method combined with ionic cross-linking to form a uniform particle size of 140–180 nm with ∼40% DOX loading efficiency. These drug-loaded CT NPs demonstrated a pH-responsive release behavior, and DOX was released more quickly under low pH values. Significant cell cytotoxicity was observed on the human hepatocarcinoma cells (HepG2 and BEL-7402) and human breast adenocarcinoma cells (MCF-7). The cell cytotoxicity and apoptosis of drug-resistant cells (MCF-7/DOX and BEL-7402/5-Fu), was greatly enhanced as compared to Adriamycin. The IC50 value showed that DOX-loaded CT NPs could be 1.5–199-fold more effective than Adriamycin. This can be attributed to the P-gp blocking and down-regulation of ATP levels by the CT NPs. The potential of these NPs to act as an oral delivery system was also investigated. Both the pharmacokinetic properties and in vivo antitumor activity of DOX-loaded CT NPs were improved compared with Adriamycin.Keywords: chitosan; doxorubicin; multidrug resistance; nanoparticles; TPGS;

AbstractVarious types of cell can change the cytoskeleton and shed microvesicles (MVs) with biomimic properties as parent cells in response to stimuli. To take use of the drug package capability of MVs and the potent antigen presentation property of dendritic cells (DCs), DC-derived antigenic MVs are constructed by priming DCs with tumor-derived MVs and then encapsulating a chemotherapeutic drug during MVs shedding. This kind of MVs exhibit significant inhibition on melanoma tumor growth and metastasis. The MV-encapsulated chemotherapeutics can induce direct cytotoxicity and immunogenic cell death in tumor cells. Moreover, a robust antitumor immunity is induced in both, the tumor-draining lymph node and the tumor microenvironment as the infiltration and activation of T lymphocytes increases. This kind of MVs is further explored in a hepatic ascites model with remarkable prolonged overall survival of mice. More importantly, the MVs can extend the survival of 60% mice more than 150 d without ascites even after rechallenging the tumor twice. This study demonstrates that antigenic MVs with chemotherapeutics possess great potential in cancer immunochemotherapy.

A redox/pH dual-sensitive graft copolymer, poly(β-amino ester)-g-D-α-tocopherol polyethylene glycol succinate (PBAE-g-TPGS), was synthesized through a Michael-type step polymerization using disulfide linkage-containing TPGS macromonomers. Pluronic F127 (F127) and folate-F127 conjugation were introduced to prepare paclitaxel (PTX)-loaded hybrid micelles to improve their biocompatibility and serum stability and also to achieve targeted delivery. The hybrid micelles exhibited in vitro redox/pH-sensitive PTX release, enhanced cellular uptake through receptor-mediated endocytosis, and strengthened anticancer activities in both the drug-sensitive human breast cancer MCF-7 and drug-resistant MCF-7/ADR cells. P-Glycoprotein inhibition by TPGS and folate-mediated targeted delivery helped overcome multidrug resistance (MDR) and increase the therapeutic efficiency of the drug, leading to good anticancer effects in the MCF-7/ADR xenograft model. Overall, the folate-modified redox/pH-sensitive hybrid micelles provided a three-step approach to enhance anticancer activities via targeted delivery, controlled release, and depressed drug efflux; thus, these micelles may be a powerful weapon against MDR cancers in the future.

Conventional tumor starving therapy by reducing its vessel density may be effective at early treatment but potentially contributes to tumor hypoxia, drug resistance and metastasis. A new strategy through enhancing tumor angiogenesis in combination with effective chemotherapeutic drugs, has shown successful tumor growth and spread inhibition. To achieve in situ release of angiogenic and antitumor drugs in tumor, we designed a precise ratiometric polymeric hybrid micelle system for co-delivering nitric oxide and paclitaxel. The hybrid micelles could accumulate in tumor via the long blood circulation and enhanced permeability and retention (EPR) effect, promote the drug accumulation and penetration in tumor by in situ increased vascular permeability, blood perfusion and vessel density, achieve the synergistic antitumor effect of nitric oxide and paclitaxel through modified tumor microenvironment, overcome multidrug resistance and inhibit metastasis. This study presents a combinational therapy against tumor progression and spread, which shows great potential in cancer therapy of the future.Download high-res image (158KB)Download full-size image

Developing multifunctional nanoparticles (NPs) to improve therapeutic efficacy is highly desirable in cancer therapy. In an attempt to respond to such a challenge, a novel copolymer, D-α-tocopherol polyethylene glycol succinate-SS-poly(lactide) (TPGS-SS-PLA) with a disulfide linkage between the TPGS and PLA units, was synthesized for paclitaxel (PTX) delivery. PTX-loaded NPs were fabricated using a nanoprecipitation method to form a particle size of ∼130 nm with good in vitro stability, which can be disassociated under intracellular reductive conditions to release PTX rapidly. The detached TPGS can further promote the drug retention and cytotoxicity through its P-glycoprotein inhibiting property. Integrin-specific targeting peptide, cyclic RGD (cRGD), was further conjugated to the surface of the NPs for targeting the drug delivery. The RGD-decorated NPs exhibited enhanced cellular uptake, PTX accumulation and cell cytotoxicity as compared to non-targeted NPs on murine melanoma B16F10 cells, PTX-sensitive human ovarian A2780 cells and PTX-resistant A2780/T cells. In vivo evaluation of the targeted NPs further showed an extended half-life, increased AUC (area under the concentration–time curve), and significant tumor growth inhibition in mouse sarcoma S180- and B16F10-tumor bearing mice, with reduced side effects as compared to Taxol® and non-targeted NPs. These results indicate that the RGD decorated redox-sensitive NPs could deliver chemotherapies specifically inside the cell via receptor-mediated endocytosis with enhanced efficacy, especially in integrin αvβ3/αvβ5-rich tumor cells. Such a targeted nanocarrier against receptor clustering prepared from a non-cytotoxic and biodegradable copolymer might have great potential in cancer treatment.

A pH-sensitive prodrug, TPGS-CHN-DOX, was introduced by conjugating anticancer drug, doxorubicin (DOX), onto d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) via a cleavable Schiff base linkage. The prodrug was mixed with a PEGylated lipid to form a simple but multifunctional hybrid micelle system, which can realize high drug loading capability and biocompatibility, extended blood circulation time, inhibited drug resistance in cancer cells, improved therapeutic response, reduced side effects, and easy functionalities for targeting delivery. The hybrid micelles exhibited in vitro pH-sensitive drug release, enhanced cellular uptake and strengthened cytotoxicity on both drug-sensitive human breast cancer MCF-7 and resistant MCF-7/ADR cells. P-glycoprotein functional inhibition and mitochondria-associated cell apoptosis induced by TPGS were thought to play an important role in overcoming the multidrug resistance. As a result, the hybrid micelles demonstrated good anticancer efficacy in MCF-7/ADR xenograft model. Additionally, after modifying with a tumor-specific targeting peptic ligand, cRGD, the tumor growth/metastasis inhibition was further evidenced in integrin receptor overexpressed melanoma cancer B16F10 and even murine hepatocarcinoma H22 models. This TPGS-based pH-sensitive prodrug provides a safe and “Molecular economical” way in the rational design of prodrugs for overcoming multidrug resistance and targeting delivery, which can improve the potency for clinical use.TPGS-CHN-DOX prodrug hybrid micelles were developed with synergistic effect of pH-triggered burst release behavior and additional bioactivity of drug carrier to overcome MDR and inhibit the potential metastasis of tumor.

Combination therapy has been regarded as a potent strategy to overcome multidrug resistance (MDR). In this study, we adopt Adjudin (ADD), a mitochondria inhibitor, and Doxorubicin (DOX), a common chemo-drug, to treat drug-resistant cancer cells (MCF-7/ADR) in combination. Given the different physico-chemical properties of ADD and DOX, we develop a novel drug formulation (ADD–DOX (M)) by integrating drug conjugation and nanocarrier approaches to realize the co-delivery of the two drugs. We demonstrate the conjugation of ADD and DOX via formation of an acid-sensitive hydrazone bond, and then the encapsulation of ADD–DOX conjugates by DSPE-PEG2000 micelles with high drug encapsulation efficiency and well-controllable drug loading efficiency. The obtained ADD–DOX (M) micelles are found to be stable under physiological conditions, but can rapidly release drugs within acidic environments. Following cellular experiments confirm that ADD–DOX (M) vehicles can be internalized by MCF-7/ADR cancer cells through an endocytic pathway and exist within the moderate acidic endolysosomes, thus accelerating the hydrolysis of ADD–DOX and the release of free ADD and DOX. As a result, the ADD–DOX (M) formulation exhibits an excellent anti-MDR effect. In summary, we for the first time report the combinational use of ADD and DOX with an effective co-delivery strategy for the treatment of MDR cancer cells.

Cancer immunotherapy is mainly focused on manipulating patient’s own immune system to recognize and destroy cancer cells. Vaccine formulations based on nanotechnology have been developed to target delivery antigens to antigen presenting cells (APCs), especially dendritic cells (DCs) for efficiently induction of antigen–specific T cells response. To enhance DC targeting and antigen presenting efficiency, we developed erythrocyte membrane-enveloped poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles for antigenic peptide (hgp10025–33) and toll-like receptor 4 agonist, monophosphoryl lipid (MPLA). A Mannose-inserted membrane structure was constructed to actively target APCs in the lymphatic organ, and redox-sensitive peptide-conjugated PLGA nanoparticles were fabricated which prone to cleave in the intracellular milieu. The nanovaccine demonstrated the retained protein content in erythrocyte and enhanced in vitro cell uptake. An antigen-depot effect was observed in the administration site with promoted retention in draining lymph nodes. Compared with other formulations after intradermal injection, the nanovaccine prolonged tumor-occurring time, inhibited tumor growth, and suppressed tumor metastasis in prophylactic, therapeutic, and metastatic melanoma models, respectively. Additionally, we revealed that nanovaccine effectively enhanced IFN-γ secretion and CD8+ T cell response. Taken together, these results demonstrated the great potential in applying an erythrocyte membrane-enveloped polymeric nanoplatform for an antigen delivery system in cancer immunotherapy.Keywords: cancer vaccine· red blood cell; dendritic cells·immunotherapy; nanoparticles;

Nitric oxide (NO) has attracted much attention for its antitumor activity and synergistic effects when codelivered with anticancer agents. However, due to its chemical instability and short half-life, delivering gaseous NO directly to tumors is still challenging. Herein, we synthesized a NO releasing polymer, nitrate functionalized d-α-tocopheryl polyethylene glycol succinate (TNO3). TNO3 was able to self-assemble into stable micelles in physiological conditions, accumulate in tumors, and release ∼90% of NO content in cancer cells for 96 h. It further exhibited significant cancer cell cytotoxicity and apoptosis compared with nitroglycerine (GTN). Notably, TNO3 could also serve as an enhancer for the common chemotherapeutic drug doxorubicin (DOX). Codelivering TNO3 with DOX to hepatocarcinoma HepG2 cancer cells strengthened the cellular uptake of DOX and enabled the synergistic effect between NO and DOX to induce higher cytotoxicity (∼6.25-fold lower IC50). Moreover, for DOX-based chemotherapy in tumor-bearing mice, coadministration with TNO3 significantly extended the blood circulation time of DOX (14.7-fold t1/2, 6.5-fold mean residence time (MRT), and 13.7-fold area under curve (AUC)) and enhanced its tumor accumulation and penetration, thus resulting in better antitumor efficacy. In summary, this new NO donor, TNO3, may provide a simple but effective strategy to enhance the therapeutic efficacy of chemotherapeutic drugs.Keywords: antitumor; doxorubicin; nitric oxide; TPGS;

•74 lyso PCs were recognized and characterized in mice serum using LC-QTOF-MS/MS.•59 lyso PCs were quantitated in hyperlipidaemic mice fed turmeric.•Preventive effects of turmeric on HFD-induced mice were elucidated.•A targeted metabolomic approach for the analysis of serum lyso PC was established.Consumption of turmeric diets demonstrated preventive effects on high-fat diet (HFD) induced hyperlipidaemia. However, the preventive effects on serum lysophosphatidylcholines (Lyso PCs) have not yet been studied. For this study, an approach for characterization of Lyso PCs in mice serum using LC-QTOF-MS/MS was developed. The preventive effects of turmeric diets were evaluated on quantitative changes of individual Lyso PCs in mice serum by LC-QTRAP-MS/MS. As a result, 74 Lyso PCs were characterized, among which 59 Lyso PCs were quantified. The results indicated that significant changes occurred for the Lyso PCs with higher degree of unsaturation in the fatty acid chain. This is the first report regarding a targeted metabolomic approach for analyses of serum Lyso PCs and its application to interpretation of preventive effects of turmeric on mice hyperlipidaemia. These metabolic changes and potential biomarkers might serve as scientific evidence for future diagnosis and therapeutic intervention of hyperlipidaemia.

Recent advances in nanotechnology and material sciences have promoted the development of nanomedicine. Among the formulations developed, novel lipid-enveloped hybrid nanoparticles have attracted more attention because of their special structure, properties and clinical applicability. The hybrid nanoparticles are composed of a hydrophilic PEG shell, a nano-sized polymeric or inorganic core and a lipid mono- or bi-layer between the core and PEG shell. This kind of nanoparticle possesses both the characteristics of liposomes and nanoparticles which endows it with many advantages like long circulation, high drug loading efficiency, high stability and biocompatibility, controlled release properties, and drug cocktail delivery. This review describes the recent developments of lipid-enveloped hybrid nanoparticles in cancer treatment, including the fabrication methods, formulations and applications of these hybrid nanoparticles. We expect that the continuing development of lipid-based nanomedicine will greatly improve cancer treatment.

Multidrug resistance (MDR) is one of the major obstacles to successful chemotherapy. Overexpression of drug efflux transporters such as P-glycoprotein (P-gp) is an important factor responsible for MDR. Herein, a novel copolymer, d-α-tocopheryl polyethylene glycol 1000-block-poly(β-amino ester) (TPGS-b-PBAE, TP), was synthesized for overcoming multidrug resistance by the synergistic effect of the pH-sensitive behavior of PBAE and P-gp inhibiting activity of TPGS. Docetaxel (DTX) was chosen as the model drug. The resulting DTX-loaded nanoparticles were stable at pH 7.4, while they dissociated in a weakly acidic environment (pH 5.5) and released the incorporated DTX quickly. The DTX-loaded TP nanoparticles increased the cell cytotoxicity against both drug-sensitive human ovarian A2780 and drug-resistant A2780/T cells. The IC50 of DTX-loaded TP against A2780/T cells was 100-fold lower than that of commercial DTX. This was associated with enhanced DTX-induced apoptosis and cell arrest in the G2/M phase. Furthermore, P-gp inhibition assays, including enhancement of the fluorescence intensity of rhodamine 123 and reduction of the intracellular ATP levels, confirmed the P-gp inhibition nature of the TP copolymer. The use of the TP copolymer is a new approach to improve the therapeutic effect of anticancer drugs in MDR tumors.

d-α-Tocopheryl polyethylene glycol 1000 succinate (simply TPGS or Vitamin E TPGS) is formed by the esterification of Vitamin E succinate with polyethylene glycol 1000. As novel nonionic surfactant, it exhibits amphipathic properties and can form stable micelles in aqueous vehicles at concentration as low as 0.02 wt%. It has been widely investigated for its emulsifying, dispersing, gelling, and solubilizing effects on poorly water-soluble drugs. It can also act as a P-glycoprotein (P-gp) inhibitor and has been served as an excipient for overcoming multidrug resistance (MDR) and for increasing the oral bioavailability of many anticancer drugs. Since TPGS has been approved by FDA as a safe pharmaceutic adjuvant, many TPGS-based drug delivery systems (DDS) have been developed. In this review, we discuss TPGS properties as a P-gp inhibitor, solubilizer/absorption and permeation enhancer in drug delivery and TPGS-related formulations such as nanocrystals, nanosuspensions, tablets/solid dispersions, adjuvant in vaccine systems, nutrition supplement, plasticizer of film, anticancer reagent and so on. This review will greatly impact and bring out new insights in the use of TPGS in DDS.Download high-res image (113KB)Download full-size image

A redox/pH dual-sensitive graft copolymer, poly(β-amino ester)-g-D-α-tocopherol polyethylene glycol succinate (PBAE-g-TPGS), was synthesized through a Michael-type step polymerization using disulfide linkage-containing TPGS macromonomers. Pluronic F127 (F127) and folate-F127 conjugation were introduced to prepare paclitaxel (PTX)-loaded hybrid micelles to improve their biocompatibility and serum stability and also to achieve targeted delivery. The hybrid micelles exhibited in vitro redox/pH-sensitive PTX release, enhanced cellular uptake through receptor-mediated endocytosis, and strengthened anticancer activities in both the drug-sensitive human breast cancer MCF-7 and drug-resistant MCF-7/ADR cells. P-Glycoprotein inhibition by TPGS and folate-mediated targeted delivery helped overcome multidrug resistance (MDR) and increase the therapeutic efficiency of the drug, leading to good anticancer effects in the MCF-7/ADR xenograft model. Overall, the folate-modified redox/pH-sensitive hybrid micelles provided a three-step approach to enhance anticancer activities via targeted delivery, controlled release, and depressed drug efflux; thus, these micelles may be a powerful weapon against MDR cancers in the future.

Developing multifunctional nanoparticles (NPs) to improve therapeutic efficacy is highly desirable in cancer therapy. In an attempt to respond to such a challenge, a novel copolymer, D-α-tocopherol polyethylene glycol succinate-SS-poly(lactide) (TPGS-SS-PLA) with a disulfide linkage between the TPGS and PLA units, was synthesized for paclitaxel (PTX) delivery. PTX-loaded NPs were fabricated using a nanoprecipitation method to form a particle size of ∼130 nm with good in vitro stability, which can be disassociated under intracellular reductive conditions to release PTX rapidly. The detached TPGS can further promote the drug retention and cytotoxicity through its P-glycoprotein inhibiting property. Integrin-specific targeting peptide, cyclic RGD (cRGD), was further conjugated to the surface of the NPs for targeting the drug delivery. The RGD-decorated NPs exhibited enhanced cellular uptake, PTX accumulation and cell cytotoxicity as compared to non-targeted NPs on murine melanoma B16F10 cells, PTX-sensitive human ovarian A2780 cells and PTX-resistant A2780/T cells. In vivo evaluation of the targeted NPs further showed an extended half-life, increased AUC (area under the concentration–time curve), and significant tumor growth inhibition in mouse sarcoma S180- and B16F10-tumor bearing mice, with reduced side effects as compared to Taxol® and non-targeted NPs. These results indicate that the RGD decorated redox-sensitive NPs could deliver chemotherapies specifically inside the cell via receptor-mediated endocytosis with enhanced efficacy, especially in integrin αvβ3/αvβ5-rich tumor cells. Such a targeted nanocarrier against receptor clustering prepared from a non-cytotoxic and biodegradable copolymer might have great potential in cancer treatment.

Combination therapy has been regarded as a potent strategy to overcome multidrug resistance (MDR). In this study, we adopt Adjudin (ADD), a mitochondria inhibitor, and Doxorubicin (DOX), a common chemo-drug, to treat drug-resistant cancer cells (MCF-7/ADR) in combination. Given the different physico-chemical properties of ADD and DOX, we develop a novel drug formulation (ADD–DOX (M)) by integrating drug conjugation and nanocarrier approaches to realize the co-delivery of the two drugs. We demonstrate the conjugation of ADD and DOX via formation of an acid-sensitive hydrazone bond, and then the encapsulation of ADD–DOX conjugates by DSPE-PEG2000 micelles with high drug encapsulation efficiency and well-controllable drug loading efficiency. The obtained ADD–DOX (M) micelles are found to be stable under physiological conditions, but can rapidly release drugs within acidic environments. Following cellular experiments confirm that ADD–DOX (M) vehicles can be internalized by MCF-7/ADR cancer cells through an endocytic pathway and exist within the moderate acidic endolysosomes, thus accelerating the hydrolysis of ADD–DOX and the release of free ADD and DOX. As a result, the ADD–DOX (M) formulation exhibits an excellent anti-MDR effect. In summary, we for the first time report the combinational use of ADD and DOX with an effective co-delivery strategy for the treatment of MDR cancer cells.