Combining sufficient stability during circulation and desirable drug release is still a great challenge for the clinical applications of nanocarriers. To satisfy this demand, we developed a novel unimolecular micelle (UM) to deliver the antitumor agent 1,2-diaminocyclohexane-platinum(II) (DACHPt) for enhanced therapy of lung cancer. This DACHPt-loaded UM (UM/DACHPt) was formed through chelate complexation between DACHPt and a hydrophilic and biodegradable dendritic block copolymer poly(amidoamine)-polyglutamic acid-b-polyethylene glycol (PAM-PGlu-b-PEG), which was composed of generation 3 PAMAM (PAMAM-G3), polyglutamic acid, and long-circulating polymer PEG. This UM/DACHPt displayed robust stability and would effectively inhibit the undesired release under physiological condition, thus exhibiting much longer in vivo half-life than diblock copolymer micelles. With significant in vitro cell cytotoxicity to A549 lung cancer cells, this UM/DACHPt demonstrated efficient antitumor efficacy on an A549 xenograft tumor model with negligible tissue cytotocxity. Therefore, this UM/DACHPt provides a promising new strategy for lung cancer therapy.Keywords: DACHPt; dendritic block copolymers; lung cancer; polyglutamic acid; unimolecular micelles;

Polymeric nanoparticles such as PLGA-based nanoparticles are emerging as promising carriers for controlled drug delivery. However, little is known about the intracellular trafficking network of polymeric nanoparticles. Here, more than 30 Rab proteins were used as markers of multiple trafficking vesicles in endocytosis, exocytosis and autophagy to investigate in detail the intracellular trafficking pathways of PLGA nanoparticles. We observed that coumarin-6-loaded PLGA nanoparticles were internalized by the cells mainly through caveolin and clathrin-dependent endocytosis and Rab34-mediated macropinocytosis. Then the PLGA nanoparticles were transported to early endosomes (EEs), late endosomes (LEs), and finally to lysosomes. Two novel transport pathways were identified in our research: the macropinocytosis (Rab34 positive)–LE (Rab7 positive)–lysosome pathway and the EE–liposome (Rab18)–lysosome pathway. Moreover, the slow (Rab11 and Rab35 positive), fast (Rab4 positive) and apical (Rab20 and Rab25 positive) endocytic recycling endosome pathways could transport the PLGA nanoparticles to lysosomes. The PLGA nanoparticles were transported out of the cells by GLUT4 transport vesicles (Rab8, Rab10 positive), classic secretory vesicles (Rab3, Rab27 positive vesicles) and melanosomes (Rab32, Rab38 positive vesicles). Besides, the PLGA nanoparticles were observed in autophagosomes (LC3 positive), which means that the nanoparticles can be delivered by the autophagy pathway. Multiple cross-talk pathways were identified connecting autophagy and endocytosis or exocytosis by screening the co-localization of the Rab proteins with the LC3 protein. Degradation of nanoparticles through lysosomes can be blocked by autophagy inhibitors (3 MA and CQ). A better understanding of intracellular trafficking mechanisms involved in polymeric nanoparticle-based drug delivery is a prerequisite to clinical application.

Cancer cells use autophagy to resist poor survival environmental conditions such as low PH, poor nutrients as well as chemical therapy. Nanogels have been used as efficient chemical drug carriers for cancer treatment. However, the effect of nanogels on autophagy is still unknown. Here, we used Rab proteins as the marker of multiple trafficking vesicles in endocytosis and LC3 as the marker of autophagy to investigate the intracellular trafficking network of Rhodamine B (Rho)-labeled nanogels. The nanogels were internalized by the cells through multiple protein dependent endocytosis and micropinocytosis. After inception by the cells, the nanogels were transported into multiple Rab positive vesicles including early endosomes (EEs), late endosomes (LEs), recycling endosomes (REs) and lipid droplets. Finally, these Rab positive vesicles were transported to lysosome. In addition, GLUT4 exocytosis vesicles could transport the nanogels out of the cells. Moreover, nanogels could induce autophagy and be sequestered in autophagosomes. The crosstalk between autophagosomes and Rab positive vesicles were investigated, we found that autophagosomes may receive nanogels through multiple Rab positive vesicles. Co-delivery of autophagy inhibitors such as chloroquine (CQ) and the chemotherapeutic drug doxorubicin (DOX) by nanogels blocked the autophagy induced by DOX greatly decreasing both of the volume and weight of the tumors in mice tumor models. Investigation and intervention of the autophagy pathway could provide a new method to improve the therapeutic effect of anticancer nanogels.

Magnetite (iron oxide, Fe3O4) nanoparticles have been widely used for drug delivery and magnetic resonance imaging (MRI). Previous studies have shown that many metal-based nanoparticles including Fe3O4 nanoparticles can induce autophagosome accumulation in treated cells. However, the underlying mechanism is still not clear. To investigate the biosafety of Fe3O4 and PLGA-coated Fe3O4 nanoparticles, some experiments related to the mechanism of autophagy induction by these nanoparticles have been investigated. In this study, the results showed that Fe3O4, PLGA-coated Fe3O4, and PLGA nanoparticles could be taken up by the cells through cellular endocytosis. Fe3O4 nanoparticles extensively impair lysosomes and lead to the accumulation of LC3-positive autophagosomes, while PLGA-coated Fe3O4 nanoparticles reduce this destructive effect on lysosomes. Moreover, Fe3O4 nanoparticles could also cause mitochondrial damage and ER and Golgi body stresses, which induce autophagy, while PLGA-coated Fe3O4 nanoparticles reduce the destructive effect on these organelles. Thus, the Fe3O4 nanoparticle-induced autophagosome accumulation may be caused by multiple mechanisms. The autophagosome accumulation induced by Fe3O4 was also investigated. The Fe3O4, PLGA-coated Fe3O4, and PLGA nanoparticle-treated mice were sacrificed to evaluate the toxicity of these nanoparticles on the mice. The data showed that Fe3O4 nanoparticle treated mice would lead to the extensive accumulation of autophagosomes in the kidney and spleen in comparison to the PLGA-coated Fe3O4 and PLGA nanoparticles. Our data clarifies the mechanism by which Fe3O4 induces autophagosome accumulation and the mechanism of its toxicity on cell organelles and mice organs. These findings may have an important impact on the clinical application of Fe3O4 based nanoparticles.

Ultraviolet (UV) radiation has deleterious effects on living organisms, and functions as a tumor initiator and promoter. Multiple natural compounds, like quercetin, have been shown the protective effects on UV-induced damage. However, quercetin is extremely hydrophobic and limited by its poor percutaneous permeation and skin deposition. Here, we show that quercetin-loaded PLGA-TPGS nanoparticles could overcome low hydrophilicity of quercetin and improve its anti-UVB effect. Quercetin-loaded NPs can significantly block UVB irradiation induced COX-2 up-expression and NF-kB activation in Hacat cell line. Moreover, PLGA-TPGS NPs could efficiently get through epidermis and reach dermis. Treatment of mice with quercetin-loaded NPs also attenuates UVB irradiation-associated macroscopic and histopathological changes in mice skin. These results demonstrated that copolymer PLGA-TPGS could be used as drug nanocarriers against skin damage and disease. The findings provide an external use of PLGA-TPGS nanocarriers for application in the treatment of skin diseases.From the Clinical EditorSkin is the largest organ in the body and is subjected to ultraviolet (UV) radiation damage daily from the sun. Excessive exposure has been linked to the development of skin cancer. Hence, topically applied agents can play a major role in skin protection. In this article, the authors developed quercetin-loaded PLGA-TPGS nanoparticles and showed their anti-UVB effect.Quercetin-loaded nanoparticles can effectively protect UVB induced damage both in vitro and in vivo experiments and PLGA-TPGS nanoparticles could also be applicable to other drugs of difficulty in formulation due to low hydrophilicity for the external use.

Poly(lactide-co-glycolide) (PLGA)-based particles have been widely used as carriers of various kinds of drugs, which are sequestered by the cell membrane and degraded through endo-lysosome and auto-lysosomal pathways. Lysosome is the destination of endocytosis and autophagy, which is also an organelle for the cell to execute death. Here, we show that chloroquine (CQ) and ciprofloxacin (CPX) (LMP inducer reagents)-loaded PLGA hollow microspheres (HMs) could be delivered by passive targeting into endo-lysosome and auto-lysosome. Co-loading with NaHCO3 accelerates the release of CQ and CPX in the acid environment of endo-lysosome and auto-lysosome. Subsequently, the released CQ and CPX induce lysosomal membrane permeabilization (LMP), which leads to cancer cell death in three different manners: apoptosis, autophagic cell death and apoptosis with autophagosome. Moreover, we use rapamycin, the inhibitor of the mammalian target of rapamycin (mTOR), to induce autophagy and inhibit cell growth. Rapamycin–NaHCO3-loaded HMs combined CQ–NaHCO3-loaded HMs could efficiently induce cancer cell death through apoptosis with autophagosome both in vitro and in vivo.

A star-shaped random copolymer, cholic acid functionalized poly(ε-caprolactone-ran-lactide)-b-poly(ethylene glycol) 1000 (CA-(PCL-ran-PLA)-b-PEG1k), was synthesized by a core-first approach involving three stages of chemical reactions, and was characterized by hydrogen-1 nuclear magnetic resonance (1H NMR), gel permeation chromatography and thermogravimetric analysis. The docetaxel-loaded nanoparticles (NPs) were prepared by a modified nano-precipitation method. The formation and characterization of these NPs were confirmed through dynamic light scattering, zeta potential measurements, field emission scanning electron microscopy, and transmission electron microscopy. The in vitro release profiles indicated that CA-(PCL-ran-PLA)-b-PEG1k NPs had excellent sustained and controlled drug release properties. Both confocal laser scanning microscope and flow cytometric results showed that the coumarin-6 loaded CA-(PCL-ran-PLA)-b-PEG1k NPs had the highest cellular uptake efficiency compared with PEG1k-b-(PCL-ran-PLA) NPs and CA-(PCL-ran-PLA) NPs in human hepatic carcinoma cells. The docetaxel-loaded CA-(PCL-ran-PLA)-b-PEG1k NPs were also proved to have the highest drug loading content, encapsulation efficiency, and the best anti-tumor efficacy both in vitro and in vivo. In conclusion, the star-shaped CA-(PCL-ran-PLA)-b-PEG1k copolymer was successfully synthesized and could be used as a promising drug-loaded biomaterial for liver cancer chemotherapy.

A novel of hydrophilic and polar N-vinylpyrrolidone modified post-crosslinked resin was synthesized and the adsorption behaviors toward puerarin from aqueous solution were investigated. The post-crosslinked adsorbent PNVP-DVBpc was prepared by Friedel–Crafts reaction of residual double bonds without external crosslinking agent. The specific surface area of precursor PNVP-DVB increased obviously after post-crosslinking modification. The synthesized adsorbents were characterized by BET surface area, Fourier transform infrared (FTIR), and scanning electron microscopy (SEM). The adsorption behaviors of puerarin from aqueous solution onto precursor PNVP-DVB and post-crosslinked adsorbent PNVP-DVBpc were thoroughly researched. Commercial polymeric adsorbents Amberlite XAD-4 and AB-8 were chosen as the comparison. Among the four media, PNVP-DVBpc presented the largest adsorption capacity of puerarin, which resulted from the synergistic effect of high specific surface area and polar groups (amide groups) onto the adsorbent matrix. Experimental results showed that equilibrium isotherms could be fitted by Freundlich model and the kinetic data could be characterized by pseudo-second order model reasonably. Column adsorption experiments indicated that the puerarin could be completely desorbed by 4.0 BV industrial alcohol. Continuous column adsorption–regeneration cycles demonstrated the PNVP-DVBpc without any significant adsorption capacity loss during operation.Graphical abstractHighlights► A novel of hydrophilic and polar post-crosslinked resin with high surface area was synthesized. ► SEM indicated that the precursor become more highly porous after the Friedel–Crafts modification. ► Post-crosslinked adsorbent showed the largest adsorption capacity of puerarin. ► The adsorption mechanism of puerarin was investigated.

The purpose of this research was to develop formulation of docetaxel-loaded biodegradable TPGS-b-(PCL-ran-PGA) nanoparticles for breast cancer chemotherapy. A novel diblock copolymer, D-α-tocopheryl polyethylene glycol 1000 succinate-b-poly(ε-caprolactone-ran-glycolide) [TPGS-b-(PCL-ran-PGA)], was synthesized from ε-caprolactone, glycolide and D-α-tocopheryl polyethylene glycol 1000 succinate by ring-opening polymerization using stannous octoate as catalyst. The obtained copolymers were characterized by 1H NMR, GPC and TGA. The docetaxel-loaded TPGS-b-(PCL-ran-PGA) nanoparticles were prepared and characterized. The data showed that the fluorescence TPGS-b-(PCL-ran-PGA) nanoparticles could be internalized by MCF-7 cells. The TPGS-b-(PCL-ran-PGA) nanoparticles achieved significantly higher level of cytotoxicity than commercial Taxotere®. MCF-7 xenograft tumor model on SCID mice showed that docetaxel formulated in the TPGS-b-(PCL-ran-PGA) nanoparticles could effectively inhibit the growth of tumor over a longer period of time than Taxotere® at the same dose. In conclusion, the TPGS-b-(PCL-ran-PGA) copolymer could be acted as a novel and potential biologically active polymeric material for nanoformulation in breast cancer chemotherapy.

Cancer is the leading cause of death worldwide. Nanomaterials and nanotechnologies could provide potential solutions. In this research, a novel biodegradable poly(lactide-co-glycolide)-d-a-tocopheryl polyethylene glycol 1000 succinate (PLGA-TPGS) random copolymer was synthesized from lactide, glycolide and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) by ring-opening polymerization using stannous octoate as catalyst. The obtained random copolymers were characterized by 1H NMR, FTIR, GPC and TGA. The docetaxel-loaded nanoparticles made of PLGA-TPGS copolymer were prepared by a modified solvent extraction/evaporation method. The nanoparticles were then characterized by various state-of-the-art techniques. The results revealed that the size of PLGA-TPGS nanoparticles was around 250 nm. The docetaxel-loaded PLGA-TPGS nanoparticles could achieve much faster drug release in comparison with PLGA nanoparticles. In vitro cellular uptakes of such nanoparticles were investigated by CLSM, demonstrating the fluorescence PLGA-TPGS nanoparticles could be internalized by human cervix carcinoma cells (HeLa). The results also indicated that PLGA-TPGS-based nanoparticles were biocompatible, and the docetaxel-loaded PLGA-TPGS nanoparticles had significant cytotoxicity against Hela cells. The cytotoxicity against HeLa cells for PLGA-TPGS nanoparticles was in time- and concentration-dependent manner. In conclusion, PLGA-TPGS random copolymer could be acted as a novel and promising biocompatible polymeric matrix material applicable to nanoparticle-based drug delivery system for cancer chemotherapy.

Cervical cancer remains a critical problem that is second only to breast cancer affecting women worldwide. The objective of this study was to develop formulation of docetaxel-loaded biodegradable poly(ɛ-caprolactone-co-lactide)-d-α-tocopheryl polyethylene glycol 1000 succinate (PCL-PLA-TPGS) nanoparticles for cervical cancer chemotherapy. A novel random copolymer, PCL-PLA-TPGS, was synthesized from ɛ-caprolactone, lactide and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) by ring-opening polymerization. The obtained polymers were characterized by 1H NMR, FTIR, GPC and TGA. The docetaxel-loaded PCL-PLA-TPGS nanoparticles were prepared by a modified solvent extraction/evaporation technique and characterized in terms of size and size distribution, morphology, surface charge and physical state of encapsulated docetaxel. Cellular uptake and in vitro cytotoxicity of nanoparticle formulations were done in comparison with commercial formulation Taxotere® to investigate the efficacy of PCL-PLA-TPGS nanoparticles. In vitro cellular uptakes of such nanoparticles were investigated with CLSM, demonstrating the coumarin 6-loaded PCL-PLA-TPGS nanoparticles could be internalized by Hela cells. In vitro cancer cell viability experiment showed that judged by IC50, the PCL-PLA-TPGS nanoparticle formulation was found to be more effective in cell number reduction than the Taxotere® after 48 h (p < 0.05), 72 h (p < 0.05) treatment. In conclusion, the PCL-PLA-TPGS copolymer could be acted as a novel and promising biologically active polymeric matrix material for nanoparticle formulation in cervical cancer treatment.

The aim of this work was to investigate the effect of triblock copolymer poloxamer 188 on nanoparticle morphology, size, cancer cell uptake, and cytotoxicity. Docetaxel-loaded nanoparticles were prepared by oil-in-water emulsion/solvent evaporation technique using biodegradable poly(lactic-co-glycolic acid) (PLGA) with or without addition of poloxamer 188, respectively. The resulting nanoparticles were found to be spherical with a rough and porous surface. The nanoparticles had an average size of around 200 nm with a narrow size distribution. The in vitro drug-release profile of both nanoparticle formulations showed a biphasic release pattern. An increased level of uptake of PLGA/poloxamer 188 nanoparticles in the docetaxel-resistant MCF-7 TAX30 human breast cancer cell line could be found in comparison with that of PLGA nanoparticles. In addition, the docetaxel-loaded PLGA/poloxamer 188 nanoparticles achieved a significantly higher level of cytotoxicity than that of docetaxel-loaded PLGA nanoparticles and Taxotere (P < .05). In conclusion, the results showed advantages of docetaxel-loaded PLGA nanoparticles incorporated with poloxamer 188 compared with the nanoparticles without incorporation of poloxamer 188 in terms of sustainable release and efficacy in breast cancer chemotherapy.From the Clinical EditorThe effects of poloxamer 188, a triblock copolymer were studied on nanoparticle morphology, size, cancer cell uptake and cytotoxicity. An increased level of uptake of PLGA/poloxamer 188 nanoparticles in resistant human breast cancer cell line was demonstrated, resulting in a significantly higher level of cytotoxicity.

Multidrug resistance (MDR) in tumor cells is a significant obstacle to the success of chemotherapy in many cancers. The purpose of this research is to test the possibility of docetaxel-loaded poly (ε-caprolactone)/Pluronic F68 (PCL/Pluronic F68) nanoparticles to overcome MDR in docetaxel-resistance human breast cancer cell line. Docetaxel-loaded nanoparticles were prepared by modified solvent displacement method using commercial PCL and self-synthesized PCL/Pluronic F68, respectively. PCL/Pluronic F68 nanoparticles were found to be of spherical shape with a rough and porous surface. The nanoparticles had an average size of around 200 nm with a narrow size distribution. The in vitro drug release profile of both nanoparticle formulations showed a biphasic release pattern. There was an increased level of uptake of PCL/Pluronic F68 nanoparticles in docetaxel-resistance human breast cancer cell line, MCF-7 TAX30, when compared with PCL nanoparticles. The cytotoxicity of PCL nanoparticles was higher than commercial Taxotere®in the MCF-7 TAX30 cell culture, but the differences were not significant (p > 0.05). However, the PCL/Pluronic F68 nanoparticles achieved significantly higher level of cytotoxicity than both of PCL nanoparticles and Taxotere®(p < 0.05), indicating docetaxel-loaded PCL/Pluronic F68 nanoparticles could overcome multidrug resistance in human breast cancer cells and therefore have considerable potential for treatment of breast cancer.

Cyclo-trans-4-l-hydroxyprolyl-l-serine (JBP485) is a dipeptide with anti-hepatitis activity that has been chemically synthesized. Previous experiments in rats showed that JBP485 was well absorbed by the intestine after oral administration. The human peptide transporter (PEPT1) is expressed in the intestine and recognizes compounds such as dipeptides and tripeptides. The purposes of this study were to determine if JBP485 acted as a substrate for intestinal PEPT1, and to investigate the characteristics of JBP485 uptake and transepithelial transport by PEPT1. The uptake of JBP485 was pH dependent in human intestinal epithelial cells Caco-2. And JBP485 uptake was also significantly inhibited by glycylsarcosine (Gly-Sar, a typical substrate for PEPT1 transporters), JBP923 (a derivative of JBP485), and cephalexin (CEX, a β-lactam antibiotic and a known substrate of PEPT1) in Caco-2 cells. The rate of apical-to-basolateral transepithelial transport of JBP485 was 1.84 times higher than that for basolateral-to-apical transport. JBP485 transport was obviously inhibited by Gly-Sar, JBP923 and CEX in Caco-2 cells. The uptake of JBP485 was increased by verapamil but not by cyclosporin A (CsA) and inhibited by the presence of Zn2+ or the toxic metabolite of ethanol, acetaldehyde (AcH) in Caco-2 cells. The in vivo uptake of JBP485 was increased by verapamil and decreased by ethanol in vivo, which was consisted with the in vitro study. PEPT1 mRNA levels were enhanced after exposure of the cells to JBP485 for 24 h, compared to control. In conclusion, JBP485 was actively transported by the intestinal oligopeptide transporter PEPT1. This mechanism is likely to contribute to the rapid absorption of JBP485 by the gastrointestinal tract after oral administration.Graphical abstractDownload full-size imageResearch highlights► JBP485 is a substrate of PEPT1 and its absorption is actively mediated by PEPT1. ► The mRNA expression of PEPT1 is increased when treated with JBP485. ► The uptake of JBP485 could be changed when coadministered with other drugs.

A star-shaped random copolymer, cholic acid functionalized poly(ε-caprolactone-ran-lactide)-b-poly(ethylene glycol) 1000 (CA-(PCL-ran-PLA)-b-PEG1k), was synthesized by a core-first approach involving three stages of chemical reactions, and was characterized by hydrogen-1 nuclear magnetic resonance (1H NMR), gel permeation chromatography and thermogravimetric analysis. The docetaxel-loaded nanoparticles (NPs) were prepared by a modified nano-precipitation method. The formation and characterization of these NPs were confirmed through dynamic light scattering, zeta potential measurements, field emission scanning electron microscopy, and transmission electron microscopy. The in vitro release profiles indicated that CA-(PCL-ran-PLA)-b-PEG1k NPs had excellent sustained and controlled drug release properties. Both confocal laser scanning microscope and flow cytometric results showed that the coumarin-6 loaded CA-(PCL-ran-PLA)-b-PEG1k NPs had the highest cellular uptake efficiency compared with PEG1k-b-(PCL-ran-PLA) NPs and CA-(PCL-ran-PLA) NPs in human hepatic carcinoma cells. The docetaxel-loaded CA-(PCL-ran-PLA)-b-PEG1k NPs were also proved to have the highest drug loading content, encapsulation efficiency, and the best anti-tumor efficacy both in vitro and in vivo. In conclusion, the star-shaped CA-(PCL-ran-PLA)-b-PEG1k copolymer was successfully synthesized and could be used as a promising drug-loaded biomaterial for liver cancer chemotherapy.

Poly(lactide-co-glycolide) (PLGA)-based particles have been widely used as carriers of various kinds of drugs, which are sequestered by the cell membrane and degraded through endo-lysosome and auto-lysosomal pathways. Lysosome is the destination of endocytosis and autophagy, which is also an organelle for the cell to execute death. Here, we show that chloroquine (CQ) and ciprofloxacin (CPX) (LMP inducer reagents)-loaded PLGA hollow microspheres (HMs) could be delivered by passive targeting into endo-lysosome and auto-lysosome. Co-loading with NaHCO3 accelerates the release of CQ and CPX in the acid environment of endo-lysosome and auto-lysosome. Subsequently, the released CQ and CPX induce lysosomal membrane permeabilization (LMP), which leads to cancer cell death in three different manners: apoptosis, autophagic cell death and apoptosis with autophagosome. Moreover, we use rapamycin, the inhibitor of the mammalian target of rapamycin (mTOR), to induce autophagy and inhibit cell growth. Rapamycin–NaHCO3-loaded HMs combined CQ–NaHCO3-loaded HMs could efficiently induce cancer cell death through apoptosis with autophagosome both in vitro and in vivo.