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Inducing mitochondrial malfunction is an appealing strategy to overcome tumor multidrug resistance (MDR). Reported here a versatile mitochondrial-damaging molecule, vitamin E succinate (VES), is creatively utilized to assist MDR reversal of doxorubicin hydrochloride (DOX·HCl) via a nanovesicle platform self-assembled from amphiphilic polyphosphazenes containing pH-sensitive 1H-benzo-[d]imidazol-2-yl) methanamine (BIMA) groups. Driven by multiple non-covalent interactions, VES is fully introduced into the hydrophobic membrane of DOX·HCl-loaded nanovesicles with loading content of 23.5%. The incorporated VES also offers robust anti-leakage property toward DOX·HCl under normal physiological conditions. More importantly, upon release within acidic tumor cells, VES can target mitochondria and result in various dysfunctions including excessive generation of reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨm) loss, and inhibited adenosine triphosphate (ATP) synthesis, which contribute to cell apoptosis and insufficient energy supply for drug efflux pumps. Consequently, the killing-effect of DOX·HCl is significantly enhanced toward drug resistant cancer cells at the optimal mass ratio of DOX·HCl to VES. Further in vivo antitumor investigation on nude mice bearing xenograft drug-resistant human chronic myelogenous leukemia K562/ADR tumors verifies the extremely enhanced anti-tumor efficacy of the dual drug-loaded nanovesicle with the tumor inhibition rate (TIR) of 82.38%. Collectively, this study provides a s safe, facile and promising strategy for both precise drug delivery and MDR eradication to improve cancer therapy.

The in vivo delivery of nanomedicine is severely hampered by the limited enhanced permeability and retention effect (EPR) in tumors. Aiming at overcoming this limitation and achieving high anti-tumor effect of chemotherapeutics, we specially addressed an available strategy from a viewpoint of increasing the drug loading of nano-carriers. Here, we constructed a novel pH-responsive polymersome based on the drug-driven self-assembly of amphiphilic polyphosphazenes PAP containing the ortho ester group ABD and mPEG2000. Due to the non-covalent attractive forces between PAP and doxorubicin hydrochloride (DOX·HCl), DOX·HCl can induce the self-assembly of PAP via embedding itself in the lamella to form vesicles and the subsequent location in the center aqueous chamber of the resultant nano-vesicles, which resulted in the high drug loading content of 35.77 wt%. In addition, with the incorporation of cholesteryl hemisuccinate (CholHS), the premature leakage of DOX·HCl was significantly inhibited under physiological conditions. Meanwhile, the pH-sensitive drug release occurred at pH 5.5 by the advantage of the pH-sensitive biodegradation of ABD in PAP. Consequently, this CholHS-incorporated DOX·HCl-driven PAP vesicle achieved excellent anti-tumor effect with tumor growth inhibition up to 82.4% in S180 tumor-bearing mice. Taken together, our newly developed drug-driven vesicles may promote the development of efficient drug delivery systems for application in cancer therapy.

Aimed at evoking an adequate anti-tumor immune response via oral administration route, this study constructed functionally and structurally mimicking-bacteria-membrane (MBM) nano-vesicle (RGD-PEOP) to orally deliver ovalbumin (OVA) antigen. In terms of simulating bacterial membrane structure, we creatively designed this nano-vesicle to have phospholipid-like octadecylphosphoethanolamine groups in vesicle membrane to improve OVA loading by means of specific interactions including salt bridge and hydrogen bond interaction. For simulating bacterial membrane function, the RGD peptide was modified onto the nano-vesicle surface, and the resulting vector displayed a good transport ability with a 3.4-fold higher than free OVA. In vitro and in vivo assay showed that the expression of co-stimulatory molecules and MHC class II complexes was significantly enhanced by MBM nano-vesicle. IFN-γ and IL-4 levels also increased several folds in the MBM nano-vesicle group. Consequently, MBM nano-vesicle achieved the highest in vivo inhibition rate of 69% against E.G7-OVA tumors among all the oral groups. These results suggest that this MBM nano-vesicle may be a promising vector to orally deliver OVA antigen for cancer immunotherapy. STATEMENT OF SIGNIFICANCE: Developing an effective non-bacterial carrier for oral cancer immunotherapy remains challenging. This work constructed a mimicking-bacteria-membrane nano-vesicle based on phospholipid-like amphiphilic polyphosphazenes for oral delivery of ovalbumin antigen. With the considerable capability to load ovalbumin antigen and target M cells, the nano-vesicle produced remarkable tumor suppression in vivo by evoking anti-tumor immune response.

L-arginine (L-Arg) is an important nitric oxide (NO) donor, and its exploration in NO gas therapy has received widespread attention. Application of nano-platforms that can efficiently deliver L-Arg and induce its rapid conversion to NO becomes a predominant strategy to achieve promising therapeutic effects in tumor treatment. Herein, an enhanced nano-vesicular system of ternary synergistic treatment combining NO therapy, photodynamic therapy (PDT) along with mild photothermal therapy (MPTT) was developed for cancer therapy. We integrated photosensitizer PEGylated indocyanine green (mPEG-ICG) into polyphosphazene PEP nano-vesicles through co-assembly and simultaneously encapsulated NO donor L-Arg into the vesicle center chambers to form mPEG-ICG/L-Arg co-loaded system IA-PEP. The unique nanostructure of vesicle provided considerable loading capacity for mPEG-ICG and L-Arg with 15.9% and 17.95% loading content, respectively, and efficiently prevented mPEG-ICG and L-Arg from leaking. Significantly, the reactive oxygen species (ROS) was produced by IA-PEP under 808 nm laser irradiation to perform PDT against tumors, which concurrently reacted with L-Arg to release NO and arouse gas therapy effectively. Moreover, the mild heat produced by IA-PEP could exhibit cooperative anti-tumor effect with minimal damage. As a consequence, in vivo antitumor investigation on nude mice bearing xenograft MCF-7 tumors verified the potent anti-tumor efficacy of IA-PEP under 808 nm laser irradiation with complete tumor elimination. Taken together, the IA-PEP nano-vesicle system designed in this work may provide a promising treatment paradigm for synergistic cancer treatment. STATEMENT OF SIGNIFICANCE: Nitric oxide (NO) gas therapy has drawn widespread attention due to its "green" treatment paradigm with negligible side effects. L-arginine (L-Arg) is an important NO donor. However, how to efficiently deliver L-Arg and induce NO generation remains a big challenge since L-Arg is a water-soluble small molecule. Herein, we developed a nano-vesicle system IA-PEP to integrate photosensitizer PEGylated indocyanine green and L-Arg with high loading content and to produce a ternary synergistic treatment combining NO therapy, photodynamic therapy (PDT) along with mild-temperature photothermal therapy (MPTT) under 808 nm laser irradiation. The in vivo investigation on nude mice bearing xenograft MCF-7 tumors verified its potent anti-tumor efficacy with complete tumor elimination.

To explore effective therapeutic strategy on nonalcoholic fatty liver disease (NAFLD), the amphiphilic oligochitosan derivative containing ursodeoxycholic acid (UDCA) was synthesized and named as UBC, which could self-assemble and encapsulate exenatide (Exe) to obtain Exe-UBC nano-vesicle. Exe-UBC could be uptaken by fatty-acid cultured cells and release UDCA and Exe responsive to the high esterase concentration. In vitro experiments demonstrated that Exe-UBC activated the expression level of SIRT1 with inhibited expression of PGC-1β and PPAR-γ and consequently exerted synergistic bioaction immediately on reducing lipidosis. After a month of Exe-UBC treated through intravenous injection, the body weight of high-fat diet feeding C57BL/6 mice recovered to ordinary level, and their lipid contents in the liver declined significantly. The recovery in hepatic function indexes like TG, AST, and ALT further revealed the superiority of Exe-UBC vesicles. These results suggested that the co-delivery of UDCA and Exe via Exe-UBC could be a potent platform for NAFLD treatment.

Carboplatin is one of the few platinum-based antitumor drugs used worldwide. Unfortunately, systemic carboplatin therapy is limited by its dose-related myelosuppression. In this study, a viable way to reduce the serious myelotoxicity of carboplatin while improving its therapeutic efficacy using amino-functionalized polyphosphazene vesicles is reported. First, three polyphosphazenes with different amino content were synthesized by amidating hydrophobic side groups; these polyphosphazenes could self-assemble into polymersomes with similar particle size and morphology. Based on FTIR analysis, hydrogen bonding interactions between the polymeric carriers and carboplatin were validated and shown to predominantly contribute to the significant improvement of drug loading in polymersomes. Therefore, it turned out that the amino level of polymers played a substantial role in carboplatin encapsulation. Then, PEAP-2-C polymersomes were optimized for further experimental verification to achieve depressed carboplatin-induced myelotoxicity as well as promote curative effects against CT-26 colon adenocarcinoma. These results in vitro and in vivo proved that amino-functionalized polyphosphazene vesicles have great potential for carboplatin delivery in the application of cancer therapy.

Acids can disturb the ecosystem of wild animals through altering their olfaction and olfaction-related survival behaviors. It is known that the main olfactory epithelia (MOE) of mammals rely on odorant receptors and type III adenylyl cyclase (AC3) to detect general odorants. However, it is unknown how the olfactory system sense protons or acidic odorants. Here, we show that while the MOE of AC3 knockout (KO) mice failed to respond to an odor mix in electro-olfactogram (EOG) recordings, it retained a small fraction of acid-evoked EOG responses. The acetic acid-induced EOG responses in wild-type (WT) MOE can be dissected into two components: the big component dependent on the AC3-mediated cAMP pathway and the much smaller component not. The small acid-evoked EOG response of the AC3 KOs was blocked by diminazene, an inhibitor of acid-sensing ion channels (ASICs), but not by forskolin/IBMX that desensitize the cAMP pathway. AC3 KO mice lost their sensitivity to detect pungent odorants but maintained sniffing behavior to acetic acid. Immunofluorescence staining demonstrated that ASIC1 proteins were highly expressed in olfactory sensory neurons (OSNs), mostly enriched in the knobs, dendrites, and somata, but not in olfactory cilia. Real-time polymerase chain reaction further detected the mRNA expression of ASIC1a, ASIC2b, and ASIC3 in the MOE. Additionally, mice exhibited reduced preference to attractive objects when placed in an environment with acidic volatiles. Together, we conclude that the mouse olfactory system has a non-conventional, likely ASIC-mediated ionotropic mechanism for acid sensing.

Plasmid DNA gp100 is able to act as an available vaccine against metastatic melanoma, but its administration is usually limited to parenteral route. Since oral delivery of plasmid DNA is intervened by various physical obstacles, here we constructed a nanogel (Alg-Tat-gp100) with multi-faceted functions through blending-by-blending method. Due to the cooperation of alginate and Tat peptide, Alg-Tat-gp100 demonstrated the significant improvement of stability in the stomach, mucus penetration ability in intestine, and transport across mucus layer and MDCK cells. Moreover, the bone marrow-derived cells were activated with an enhanced co-stimulatory molecule expression. Following immunization using Alg-Tat-gp100 nanogels in C57BL/6 mice, the secretion of IFN-γ and the activation of cytotoxic T cells were significantly improved. Benefiting from those cases, the B16F10 tumor inhibition rate achieved 42.5% by this oral DNA vaccine, suggesting that this multi-faceted nanogel prepared by simple blending-by-blending method may provide a new strategy for oral DNA vaccine delivery.

Clinical extensive application of indocyanine green (ICG) is limited by several drawbacks such as poor bioenvironmental stability, aggregate propensity, and rapid elimination from the body, etc. In this study, we construct a novel amphiphilic mPEG-ACA-ICG conjugate by modifying synthetic heptamethine cyanine derivative ICG-COOH with a hydrophobic linker 6-aminocaproic acid (ACA) and amino-terminal poly(ethylene glycol) (mPEG-NH2). The as-prepared mPEG-ACA-ICG conjugate has the ability to self-assemble into micellar aggregates in an aqueous solution with a lower CMC value than mPEG-ICG conjugate without ACA linker. More importantly, compared with free ICG and mPEG-ICG conjugate, mPEG-ACA-ICG nanomicelles exhibited better stability and higher photothermal conversion efficiency upon near-infrared light irradiation due to the intramolecular introduction of a hydrophobic ACA segment. In our in vivo experiment, mPEG-ACA-ICG nanomicelles ensured the formidable effect on tumor photothermal therapy (PTT) and the maximum tumor inhibition rate reached 72.6 %. In addition, real-time determination ability for fluorescence image-guided surgery (FIGS) of mPEG-ACA-ICG nanomicelles was also confirmed on tumor xenograft mice model. Taken together, mPEG-ACA-ICG conjugate may hold great promise for non-invasive cancer theranostics.

Aim: In this study, we constructed a novel vector (BioPf-M-loaded Alg-microparticles [Alg-BioPf-M]) with nano-in-micro structure to improve the oral absorption of docetaxel (DTX) by sequentially dual-targeting functions toward intestine and sodium-dependent multivitamin transporter based on entrapping biotin-modified micelles into alginate microparticles. Methods: A series of characteristics of this system was investigated, such as drug release, cellular uptake, transport pathway and the comprehensive in vivo studies including pharmacokinetic studies, anti-tumor activity and toxicity study. Results: The bioavailability of DTX-loaded Alg-BioPf-M was 27.4-fold higher than that of free DTX after oral administration and achieved superior tumor inhibition of 84.6% against sarcoma 180 tumors. Conclusion: These results demonstrated that the Alg-BioPf-M was a promising vector for oral delivery of DTX.

MiR-200c has been confirmed to display remarkable effects on proliferation inhibition and apoptosis induction of certain cancer cells, but the main challenge for its successful translation into the clinic remains its effective delivery to the action site in vivo. In this study, a novel composite polyphosphazene vesicle system composed of amphiphilic [NP(PEG)0.3(EAB)1.7]n (PEEP) and weakly cationic [NP(PEG)0.5(DPA)1.5]n (PEDP) was prepared via a very simple dialysis method. The loading of miR-200c was accomplished with high efficiency by taking advantage of the combination effect of physical encapsulation and electrostatic interaction between vectors and miR-200c. The resultant miR-200c-loaded PEEP-PEDP polymersome (Nano-ED-200c) displayed suitable particle size, electric neutrality, excellent Ribonuclease stability and hemocompatibility. We also evaluated its subsequent miR-200c function in paclitaxel resistance human lung cancer (A549/T) cells in culture and tumor xenografts in nude mice. The results showed that Nano-ED-200c could achieve a higher miR-200c level and the enhanced antitumor efficacy with 68% tumor inhibition ratio at a very low dose of 1.0 mg/kg than PEEP nanoparticle, PEDP nanoparticle, even than Lipo2000. All these evidences indicated that this miR-200c delivery via polyphosphazene vesicles could act as a potential new therapeutic option for paclitaxel resistant human lung cancer.

Understanding how the size of nanocarriers affects their fate in biological systems in vivo is of fundamental importance for rational design of drug delivery systems. In this study, five docetaxel (DTX)-loaded methoxy poly(ethylene glycol)-poly(lactide) micelles of different sizes (30-230nm) were prepared. It was observed that the permeation of micelles within both the multicellular tumor spheroids and tumor xenografts in mice was dependent on the size of the micelle. In addition, the size of micelles influenced their pharmacokinetic behavior. DTX-loaded pH-sensitive micelle based on poly(ethylene glycol)-poly(lactide)-poly(β-amino ester) (DTX-pHPM) was constructed to further illustrate the effect of particle size. As expected, DTX-pHPM improved tumor penetration, uptake by tumor cells, and prolonged circulation time, consequently demonstrating the highest inhibition of in vivo tumor growth (84.4%) in oral epidermoid carcinoma. Taken together, our findings can aid in designing nano-scale drug delivery systems for cancer therapy by optimizing the particle size.

Lu Zhang,1–3 Jiafei Lu,3 Liyan Qiu1 1Ministry of Education (MOE) Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 2Drug Clinical Trial Office, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 3College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, People’s Republic of China Abstract: P-glycoprotein (P-gp) overexpression has become the most common cause of occurrence of multidrug resistance in clinical settings. We aimed to construct a micellar polymer carrier to sensitize drug-resistant tumors to doxorubicin (DOX). This A-B-C-type amphiphilic copolymer was prepared by the sequential linkage of β-cyclodextrin, hydrophobic poly(D,L-lactide), and hydrophilic poly(ethylene glycol). Upon incubation of the DOX-loaded micelles with DOX-resistant human breast carcinoma MCF-7/ADR cells, significantly enhanced cytotoxicity and apoptosis were achieved. A series of studies on the action mechanism showedthat the polymer components such as β-cyclodextrin, hydrophobic poly(D,L-lactide) segment, and poly(ethylene glycol) coordinatively contributed to the improved intracellular ATP depletion and ATPase activity, increased intracellular uptake of P-gp substrates via competitive binding to P-gp, and decreased P-gp expression in MCF-7/ADR cells. More interestingly, a similar phenomenon was observed in the zebrafish xenograft model, resulting in ~64% inhibition of MCF-7/ADR tumor growth. These results implied that the polymeric micelles displayed great potentials as P-gp modulators to reverse DOX resistance in MCF-7/ADR breast carcinoma. Keywords: multidrug resistance, P-glycoprotein, micelle, doxorubicin, zebrafish

Abnormal lipid metabolism is a hallmark of tumorigenesis. Accumulating evidence demonstrates that fatty acid synthase (FAS, FASN) is a metabolic oncogene that supports the growth and survival of tumor cells and is highly expressed in many cancers. Here, we report that the oncoprotein, hepatitis B X-interacting protein (HBXIP, LAMTOR5) contributes to abnormal lipid metabolism. We show that high expression of HBXIP in 236 breast cancer patients was significantly associated with decreased overall survival and progression-free survival. Interestingly, the expression of HBXIP was positively related to that of FAS in clinical breast cancer tissues, and HBXIP overexpression in breast cancer cells resulted in FAS upregulation. Mechanistically, HBXIP upregulated SREBP-1c (SREBF1), which activates the transcription of FAS, by directly interacting with and coactivating nuclear receptor (NR) liver X receptors (LXR). Physiologically, LXRs are activated via a coactivator containing NR motif in a ligand-dependent manner. However, in breast cancer cells, HBXIP containing the corepressor/nuclear receptor motif with special flanking sequence could coactivate LXRs independent of ligand. Moreover, overexpressed SREBP-1c was able to activate the transcription of HBXIP, forming a positive-feedback loop. Functionally, HBXIP enhanced lipogenesis, resulting in the growth of breast cancer cells in vitro and in vivo. Thus, we conclude that the oncoprotein HBXIP contributes to the abnormal lipid metabolism in breast cancer through LXRs/SREBP-1c/FAS signaling, providing new insights into the mechanisms by which cancer cells reprogram lipid metabolism in their favor. Cancer Res; 76(16); 4696–707. ©2016 AACR.

Chemotherapy is one of the main strategies for cancer treatment, but its effective application is seriously limited by the development of drug resistance. In this study, we designed micellar vectors for doxorubicin based on amphiphilic copolymers sequentially linking β-cyclodextrin (β-CD), polylacticacid (PLA) or polycaprolactone (PCL) block, and polyethylene glycol (PEG) block to overcome drug resistance in human acute myeloid leukemia cells (HL60/ADR) overexpressing multidrug resistance protein 1 (MRP1). The significant enhancement in cytotoxicity and inhibited HL60/ADR tumor growth in mouse was achieved. More importantly, several analyses were performed to understand the interactions between various polymers and MRP1 at the cellular level. The results showed that the polymers did not show remarkable correlation of MRP1 gene and protein expression, but could decrease intracellular ATP, mitochondrial membrane potential and glutathione levels, which was greatly dependent on the molecular structure of polymers. In conclusion, these novel micelles can be considered as a kind of promising drug delivery system for tumor therapy to reverse drug resistance related to MRP1 overexpression.

Polymersomes represent a promising pharmaceutical vehicle for the delivery of hydrophilic therapeutic agents. However, modification of polymersomes with molecules that confer targeting functions remains challenging because of the strict requirements regarding the weight fractions of the hydrophilic and hydrophobic block polymers. In this study, based on the compatibility between cholesterol and polymeric carriers, polymersomes self-assembled by amphiphilic graft polyphosphazenes were endowed with a targeting function by incorporating the cholesterol-linked aptamer through a simple dialysis method. The aqueous interior of the polymersomes was employed to encapsulate water-soluble doxorubicin hydrochloride. In vivo experiments in tumor-bearing mice showed that the aptamer-anchored vesicle targeted accumulation at the tumor site, favorable penetration through tumor tissue, and incremental endocytosis into tumor cells. Correspondingly, the aptamer-anchored vesicle decreased systemic toxicity and effectively suppressed the growth of subcutaneous MCF-7 xenografts. These findings suggested that vesicles modified with targeted groups via hydrophobic supermolecular interactions could provide a platform for selective delivery of hydrophilic drug. Statement of Significance Polymersomes have represented a promising type of pharmaceutical vehicles due to their predominant physical properties. However, it is still a challenge to endow polymersomes with active target function because of strict requirements of the weight fractions of hydrophilic polymer block to hydrophobic one. In this research, by taking advantage of the supermolecular interactions between amphiphilic graft polyphosphazene and cholesterol which was linked to aptamer AS1411, we prepared a targeted functional polymersome (PEP-DOX·HCl-Ap) through a simple method with high loading of water soluble anti-cancer drug doxorubicin hydrochloride. The in vivo experiments in MCF-7 tumor-bearing mice demonstrated several advantages of PEP-DOX·HCl-Ap vesicle such as prolonged circulation time in blood, targeted accumulation at tumor site, permeation through the tumor tissue and incremental endocytosis by tumor cells, which consequently resulted in the significantly improved anti-cancer efficacy. Moreover, this novel polymersome designed in this study has built a research platform to achieve targeted delivery of hydrophilic chemotherapeutics for cancer therapy.

The conventional chemotherapeutic agent doxorubicin hydrochloride (DOX·HCl) is often accompanied by drug resistance which has severely hindered its clinical application. By taking advantage of the self-assembled behavior of amphiphilic polyphosphazenes, we constructed novel polymersomes loading DOX·HCl or desalted DOX with chloroquine phosphate (CQ) as a drug resistance-reversal agent at 1:1 or 2:1 weight ratios via a one-step common dialysis method. The cytotoxicity evaluation of this dual drug-loaded polymersome was performed on DOX-resistant MCF-7/Adr breast cancer and HL60/Adr leukemia cells. Simultaneously, to simulate in vivo cancerous tissue, 3D tumor spheroid was constructed for tissue penetration and anti-cancer effect evaluation. As a result, PEP-DHC-1 containing DOX·HCl and CQ at 1:1 weight ratio exhibited the strongest toxicity. Furthermore, the in vivo tumor inhibition study carried out on a zebrafish xenograft model also validated that PEP-DHC-1 made the outstanding contribution to improve the sensitivity of MCF-7/Adr breast cancer to chemotherapeutics. These findings suggest that this DOX·HCl and CQ co-delivery system based on PEP polymersomes might be promising for drug resistance reversal of cancer therapy and consequently enhanced anti-cancer efficacy.

Aptamers are single-stranded RNA or DNA ligands that can specifically bind to various molecular targets with high affinity. Owing to this unique character, they have become increasingly attractive in the field of drug delivery. In this study, we developed a multifunctional composite micelle (CM) with surface modification of aptamer AS1411 (Ap) for targeted delivery of doxorubicin (DOX) to human breast tumors. This binary mixed system consisting of AS1411 modified Pluronic F127 and beta-cyclodextrin-linked poly(ethylene glycol)-b-polylactide could enhance DOX-loading capacity and increase micelle stability. Cellular uptake of CM-Ap was found to be higher than that of untargeted CM due to the nucleolin-mediated endocytosis effect. In vivo study in MCF-7 tumor-bearing mice demonstrated that the AS1411-functionalized composite micelles showed prolonged circulation time in blood, enhanced accumulation in tumor, improved antitumor activity, and decreased cardiotoxicity. In conclusion, aptamer-conjugated multifunctional composite micelles could be a potential delivery vehicle for cancer therapy.

A polymersome system for delivering protein antigen ovalbumin (OVA) based on amphiphilic polyphosphazene grafting with N,N-diisopropylethylenediamine (DPA) and poly(ethylene glycol) (PEG) groups (poly[(DPA)m (PEG)n phosphazene], PEDP) was designed and constructed. The 200-240 nm-size OVA-loaded polymersomes displayed high stability at physiological pH, slow internalization through clathrin-mediated endocytosis pathway, and then a pH-triggered sustained OVA release in acidic environment, leading to extensive antigen access to cytosol. Prime-boost vaccine kept high antibody titers for 8 weeks and the subcutaneous vaccine of OVA polymersomes biased the immune response towards a type 1 T helper (Th1) response. Animal experiment results showed that the antigen-specific prophylactic vaccination by PEDP polymersomes delivery was much more rapid and efficient in depressing tumor growth and progress when compared with the therapeutic vaccination. These results suggested that PEDP-based polymersomes are very promising in controlled cytosolic delivery of protein antigens, and enhanced Th1 specific immune response.

Combretastatin A4 phosphate (CA4P) is a novel vascular disrupting agent for cancer therapy. However, frequent dosing and negative patient compliance have been encountered over CA4P by injection administration due to its quite short-term action and acute side effects. Therefore, it is significant to develop an oral formulation of CA4P. We established a novel method to prepare CA4P-loaded nanoparticles (CA4P-NPs) for oral administration by combining methoxy poly(ethylene glycol)-b-polylactide (PELA) and poly(d,l-lactic-co-glycolic acid) (PLGA) polymers. Transport study in vitro was evaluated on Madin-Darby canine kidney cell models, and antitumor effect evaluation in vivo was performed on S180 subcutaneous xenotransplanted tumor models in mice. The highest entrapment efficiency of CA4P-NPs was achieved when the weight ratio of PELA to PLGA was optimized to 1:1. The apparent permeability coefficient of CA4P-NPs was found to be 2.08-fold higher than that of free CA4P in transport study. CA4P-NPs reached an absolute bioavailability of 77.6% with the tumor inhibition ratio of 41.2% that was significantly superior to free CA4P. These results suggest a promising application of this composite nanoparticle for the oral delivery of water-soluble drugs.

Breast cancer remains one of the most common cancers for females. Drug delivery based on cancer nanotechnology could improve the performance of some chemotherapeutic medicines already used in clinic. The emergence of polymersomes provided the potential to encapsulate hydrophobic/hydrophilic drugs. By modifying the weight ratio of methoxy-poly (ethylene glycol) (mPEG) chain to ethyl-p-aminobenzoate (EAB) side group, a series of amphiphilic graft polyphosphazenes (PEPs) was prepared. PEP can be tuned from micelles to polymersomes with the decrease of mPEG content via dialysis. Either hydrophilic doxorubicin hydrochloride (DOX·HCl) or hydrophobic doxorubicin base (DOX) could be encapsulated into PEP polymersomes with high payload and high encapsulation efficiency due to the strong intermolecular interaction with PEP. Compared with free DOX·HCl administration, in vivo investigation in growth inhibition of MCF-7 xenograft tumors in nude mice demonstrated that PEP polymersomes could enhance life safety without compromise of therapeutic efficacy, especially DOX·HCl loaded delivery system. From the Clinical Editor In this preclinical study, polymerosomes based on PEPs were investigated as doxorubicin delivery systems, demonstrating similar efficacy but less toxicity compared to standard delivery methods.

The transmembrane transport of drug loaded micelles to intracellular compartment is quite crucial for efficient drug delivery. In the current study, we investigated the cellular internalization and anticancer activity of doxorubicin loaded micelles with folate modified stealthy PEOz corona. Folate-decorated micelles incorporating doxorubicin were characterized for particle size, degree of folate decoration, drug loading content and encapsulation efficiency, morphology, and surface charge. The targeting capability and cell viability were assessed using HeLa, KB, A549 and MCF-7/ADR cell lines. In vitro study clearly illustrated the folate receptor (FR) mediated targeting of FA modified micelles to FR-positive human HeLa, KB and MCF-7/ADR cells, while specific delivery to FR-negative A549 cells was not apparently increased at the same experimental conditions. Cytotoxicity assay showed 60% and 58% decrease in IC50 values for HeLa and KB cells, while only a slight decrease for A549 cells, following treatment with folate modified formulations. The enhanced intracellular delivery of FA modified micelles in MCF-7/ADR cells was also observed. In vivo antitumor tests revealed DOX entrapped FA-PEOz-PCL micelles effectively inhibited the tumor growth and reduced the toxicity to mice compared with free DOX. The current study showed that the targeted nano-vector improved cytotoxicity of DOX and suggested that this novel PEOz endowed stealthy micelle system held great promise in tumor targeted therapy.

Adenosine triphosphate (ATP)-binding cassette (ABC) transporters play a key role in the development of multidrug resistance (MDR) in cancer cells. P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1) are important proteins in this superfamily which are widely expressed on the membranes of multidrug resistance (MDR) cancer cells. Besides, upregulation of cellular autophagic responses is considered a contributing factor for MDR in cancer cells. We designed a liposome system co-encapsulating a chemotherapeutic drug (doxorubicin hydrochloride, DOX) and a typical autophagy inhibitior (chloroquine phosphate, CQ) at a weight ratio of 1:2 and investigated its drug resistance reversal mechanism. MTT assay showed that the IC

To circumvent the severe toxicity of the systemic delivery of IL-12 protein and the limits of local administration of IL-12 gene, we constructed a polymersome system for systemic delivery of recombinant murine IL-12 plasmid (pmIL-12) based on amphiphilic polyphosphazenes containing weakly cationic N,N-diisopropylethylenediamine (DPA) as hydrophobic groups and monomethoxy poly(ethylene glycol) (mPEG) as hydrophilic tails. By simple dialysis method, pmIL-12 was successfully loaded into polymersomes due to the combination effect of physical encapsulation and electrostatic interaction. This pmIL-12 polymersome delivery system was validated with good biocompatibility and stability despite of serum protein and DNase challenging. The results of in vivo antitumor experiments showed that intravenous injection of pmIL-12 polymersomes achieved significant suppression of tumor growth in BALB/c mice bearing CT-26 colon carcinoma. The analysis revealed that the mechanism was related to the antitumor immune response induced by efficient transfection of pmIL-12 polymersomes, which maybe involved lymphocytes infiltration and angiogenic inhibition at the tumor site.

To date, improving oral bioavailability of water-soluble drugs with poor membrane permeability is still challenging. An example of this includes doxorubicin hydrochloride (DOX·HCl), a widely used chemotherapeutic. We therefore developed a novel DOX·HCl-loaded polymersome (Ps-DOX·HCl) self-assembled by amphiphilic β-cyclodextrin-centered triarm star polymer (mPEG(2k)-PLA(3k))3-CD with the considerable drug loading capability. Using Madin-Darby canine kidney (MDCK) cells trans-well models, it was found that the cellular uptake and absorptive transport of DOX·HCl was significantly increased and the efflux was attenuated when delivered through polymersomes than free drugs. This phenomenon was further verified in mechanistic studies, which was attributed to the change in membrane transport pathway from paracellular route (free DOX·HCl) to active transcellular transport (drug-loaded polymersomes). Moreover, in vivo pharmacokinetic studies in mice demonstrated a significant increase in the oral bioavailability of Ps-DOX·HCl compared with free DOX·HCl (7.32-fold), as well as extended half-life (8.22-fold). This resulted in a substantial anticancer efficacy against mouse sarcoma 180 (S180) tumor in vivo. The cardiotoxicity, which is intrinsically induced by DOX·HCl, and toxicity toward gastrointestinal tissues were avoided according to histological studies. These findings indicate that (mPEG(2k)-PLA(3k))3-CD copolymer displays great potential as a vehicle for the effective oral delivery of water-soluble drugs with low permeability.

Emerging evidence has shown that hepatitis B virus (HBV) X protein (HBx) plays a crucial role in the development of hepatocellular carcinoma. Complement regulatory proteins including CD46, CD55 and CD59 contribute to escape of tumor cells from complement-dependent cytotoxicity (CDC). However, little is known about the potential role of HBx in anti-CDC activity during hepatocarcinogenesis. In the present study, we for the first time report that HBx decreases the sensitivity of hepatoma and hepatic cells to CDC. Coincidentally, we demonstrated that HBx increased the promoter activity of CD59, as well as their messenger RNA and protein levels. Moreover, flow cytometry showed the increased expression level of CD59 protein on the surface of HBx-positive cells. Of interest, we found that HBx up-regulated CD59 by binding with cAMP response element-binding to the promoter region of the CD59 gene using chromatin immunoprecipitation assay. In addition, we showed that HBx up-regulated CD59 by let-7i at post-transcriptional regulation level. Our data showed that the deposition of C5b-9 were decreased on the cell surface in HepG2-X cells relative to HepG2 cells, suggesting that increased CD59 mediated by HBx prevents the formation of functional membrane attack complex. Furthermore, we demonstrated that down-regulation of CD59 was sufficient to abolish the resistance capability of CDC in HBx-positive cells by RNA interference (siRNA) in vitro and in vivo. Thus, we conclude that HBx contributes to cells resistance to CDC through CD59. Therapeutically, CD59 may serve as a target in HBV-associated hepatoma patients.

Objectives Polymeric nanoparticles have been extensively studied as drug carriers. Chitosan and its derivatives have attracted significant attention in this regard but have limited application because of insolubility in biological solution. In this work, we attempted to utilize cholesterol-modified glycol chitosan (CHGC) self-aggregated nanoparticles to increase aqueous solubility, and to reduce side effects and enhance the antitumour efficacy of the anticancer drug doxorubicin. Methods CHGC nanoparticles were loaded with doxorubicin by a dialysis method, and their characteristics were determined by transmission electron microscopy examination, light-scattering study, in-vitro drug-release study, pharmacokinetic study in rats and in-vivo antitumour activity in mice. Key findings The resulting doxorubicin-loaded CHGC nanoparticles (DCNs) formed self-assembled aggregates in aqueous medium. From the observation by transmission electron microscopy, DCNs were almost spherical in shape. The mean diameters of these nanoparticles determined by dynamic light scattering were in the range of 237–336 nm as the doxorubicin-loading content increased from 1.73% to 9.36%. In-vitro data indicated that doxorubicin release from DCNs was much faster in phosphate-buffered saline at pH 5.5 than at pH 6.5 and 7.4, and the release rate was dependent on the loading content of doxorubicin in these nanoparticles. It was observed that DCN-16 (drug loaded content: 9.36%) exhibited prolonged circulation time in rat plasma and showed higher antitumour efficacy against S180-bearing mice than free doxorubicin. Conclusions These results indicated that CHGC nanoparticles had potential as a carrier for insoluble anticancer drugs in cancer therapy.

Preparation, in vitro and in vivo evaluation of indomethacin-loaded polymeric micelles based on amphiphilic polyphosphazene. Amphiphilic polyphosphazenes (PNIPAAm/EAB-PPPs) with poly (N-isopropylacrylamide) (PNIPAAm) and ethyl 4-aminobenzoate (EAB) as side groups were synthesized through thermal ring-opening polymerization and subsequent substitution reactions. Indomethacin (IND) loaded polymeric micelles based on PNIPAAm/EAB-PPPs were prepared by dialysis procedure. In vitro IND release kinetics was investigated in 0.1 M PBS (pH 7.4), while in vivo pharmacokinetics was performed in Sprague–Dawley rats. In vivo pharmacodynamic study was carried out based on two animal models, i.e. carrageenan-induced acute paw edema and complete Freund’s adjuvant (CFA) induced ankle arthritis model. Drug loading capacity of micelles based on this type of amphiphilic copolymers was mainly determined by copolymer composition and the chemical structure of drug. In addition to the compatibility between drug and micellar core, hydrogen bonding interaction between drug and hydrophilic corona may significantly influence drug loading as well. In vitro drug release in PBS suggested that there was no significant difference in release rate between micelles based on copolymers with various EAB content. Compared with the rats administered with free IND aqueous solution, IND concentration in rats’ plasma showed a prolonged maintenance in experimental group treated with IND-loaded polymeric micelles. In vivo pharmacodynamic study indicated that sustained therapeutic efficacy could be achieved through topical injection of the aqueous solution of IND-loaded micelles. Local delivery of IND can avoid the severe gastrointestinal stimulation, which was frequently associated with oral administration as evidenced by ulceration evaluation. The promising results of current preliminary study suggest that this type of amphiphilic copolymers could be used as injectable drug carriers for hydrophobic drugs.

In this study, we designed biodegradable polymersomes for co-delivery of an antiangiogenic drug combretastatin-A4 phosphate (CA4P) and doxorubicin (DOX) to collapse tumor neovasculature and inhibit cancer cell proliferation with the aim to achieve synergistic antitumor effects. The polymersomes co-encapsulating DOX and CA4P (Ps-DOX-CA4P) were prepared by solvent evaporation method using methoxy poly(ethylene glycol)-b-polylactide (mPEG-PLA) block copolymers as drug carriers. The resulting Ps-DOX-CA4P has vesicles shape with uniform sizes of about 50 nm and controlled co-encapsulation ratios of DOX to CA4P. More importantly, Ps-DOX-CA4P (1:10) showed strong synergistic cytotoxicity (combination index CI = 0.31) against human nasopharyngeal epidermal carcinoma (KB) cells. Furthermore, Ps-DOX-CA4P accumulated remarkably in KB tissues xenografts in nude mice. Consistent with these observations, Ps-DOX-CA4P (1:10) achieved significant antitumor potency because of fast tumor vasculature disruption and sustained tumor cells proliferation inhibition in vivo. The overall findings indicate that co-delivery of an antiangiogenic drug and a chemotherapeutic agent in polymersomes is a potentially promising strategy for cancer therapy.

Aim: Indocyanine green (ICG) is a promising near-infrared (NIR) dye for tumor imaging and photothermal therapy; however, the poor stability and lack of targeting limit its application. In this study, ICG was encapsulated into folate-conjugated poly(2-ethyl-2-oxazoline)-b-poly(ε-caprolactone) micelles to overcome these problems. Materials & methods: ICG-loaded micelles were prepared by solvent evaporation method. Cell uptake and in vitro photothermal cytotoxicity were evaluated on KB cells. In vivo NIR imaging and photothermal therapy were conducted on KB tumor-bearing mice. Results: ICG-loaded micelles with favorable sizes and stable NIR optical properties were successfully prepared. These micelles could target to KB tumors and enabled high-resolution NIR imaging. Moreover, they could effectively convert the absorbed NIR laser energy into heat, resulting in significant tumor damage and inhibition. Conclusion: This novel micellar system, integrating stable NIR properties, excellent tumor targeting and photothermal capability, showed great potential in tumor imaging and therapy.

The effects of copolymer composition, drug structure and initial drug feed on drug loading of polymeric micelles based on amphiphilic polyphosphazenes were investigated. It was found that the drug loading capacity of micelles based on this type of amphiphilic copolymers was mainly determined by copolymer composition and the chemical structure of drug. In addition to the compatibility between drug and micellar core, hydrogen bonding interaction between drug and hydrophilic corona may significantly influence drug loading as well. In vitro drug release in 0.1 M PBS (pH 7.4) suggested that indomethacin (IND) in the micelles was released through Fickian diffusion, and no significant difference in release rate was observed for micelles based on copolymers with various EtTrp content. Compared with in vitro IND release profile, in vivo pharmacokinetic study after subcutaneous administration provides a more sustained release behavior. Additionally, in comparison with free drug solution at the same dose, IND concentration in rat plasma showed a prolonged retention when the drug was delivered through polymeric micelles. In vivo pharmacodynamic study based on both carrageenan-induced acute and complete Freund's adjuvant-induced adjuvant arthritis model indicated that sustained therapeutic efficacy could be achieved through intraarticular injection of IND-loaded micelles. Most importantly, local delivery of IND can avoid the severe gastrointestinal stimulation, which was frequently associated with oral administration.

In order to enhance the antitumor effects of doxorubicin (DOX), a novel micellar vector with high DOX loading and tumor targeting function based on folate-conjugated amphiphilic copolymer folate-poly(ethylene glycol)-poly(d,l-lactide)-β-cyclodextrin (FA-PEL-CD) was constructed. Cytotoxicity and cellular uptake experiments were performed in HeLa, KB, and A549 cell lines expressing different amounts of folate receptors in order to evaluate the targeting effect of the folate modification. The antitumor experiments performed in a KB cell-xenografted nude mouse model showed that the treatment with 10mg/kg DOX loaded FA-PEL-CD micelles achieved approximately 86% of tumor growth inhibition compared to the control. Ex vivo fluorescence imaging experiments and histological examination confirmed that folate modification can enhance the antitumorigenesis efficacy and reduce the cardiotoxicity of DOX. These results suggest that FA-PEL-CD copolymer-based micelles are promising nanocarriers for targeted doxorubicin delivery, with improved antitumor efficacy and reduced toxicity in normal tissues.

Modifying positive surface charge and reducing bulk size of nanoparticles has been proven beneficial to cancer cellular delivery, but meanwhile results in fast clearance and unspecific distribution in body after intravenous injection. How to balance these problems is still a challenge to construct an ideal nano-scaled drug delivery system in cancer treatment. Herein, we developed a multistage drug delivery system to enhance anticancer efficacy of curcumin (CUR), which could intelligently alter its size and surface charge after long-circulation and extravasation from leaky blood vessels at tumor sites. This micellar system was constructed by amphiphilic and pH-sensitive methoxy poly(ethylene glycol)-poly(lactide)-poly(β-amino ester) (MPEG-PLA-PAE) copolymers. As compared with MPEG-PLA micelles, MPEG-PLA-PAE micelles displayed several advantageous characteristics for drug delivery and treatment. We found that CUR-loaded MPEG-PLA-PAE micelles remained stable in murine plasma at 37 °C even with high drug loading. More interestingly, when the media pH decreased from 7.4 to 5.5, the micelles shrank from 171.0 nm to 22.6 nm and their surface charge increased to 24.8 mV meanwhile, which resulted in the significantly improved cell uptake of CUR by human breast cancer MCF-7 cells. Using indocyanine green (ICG) as a fluorescence probe, it was observed that MPEG-PLA-PAE micelles experienced longer circulation than MPEG-PLA micelles followed by accumulation at tumors with stronger fluorescence intensity. Consequently, MPEG-PLA-PAE micelles achieved enhanced cancer growth inhibition of 65.6% in vivo. All these findings demonstrated the potential of size/charge-changing MPEG-PLA-PAE micelles as a promising drug delivery system for tumor-targeted therapy.

Aptamers are a class of oligonucleotides that can specifically bind to different targets with high affinity. Since their discovery in 1980s, aptamers have attracted considerable interests in medical applications. So far, initial research using aptamers as delivery systems has produced exciting results. In this review, we summarize recent progress in aptamer-mediated chemotherapeutic drug and siRNA delivery systems in tumor treatment. With regard to chemotherapeutic drugs, the 2 main methods for targeted delivery using aptamers are as follows: aptamer-drug systems (in which aptamers directly deliver the drug both as a carrier and as a ligand) and aptamer-nanoparticles systems (in which nanoparticles function together with aptamers for targeted delivery of drugs). For delivery of siRNA, aptamers can be utilized by the following ways to facilitate targeting: (1) linked by a connector; (2) form a chimera; and (3) combined with nanoparticles. In co-delivery system, the advantages associated with the use of aptamers are beginning to become apparent also. Here, the challenges and new perspectives in the field of aptamer-mediated delivery have been discussed.

A novel biodegradable and injectable in situ gel-forming controlled drug delivery system based on thermosensitive β-cyclodextrin-modified poly(e-caprolactone)-poly(ethylene glycol)-poly(e-caprolactone) co-polymer (PCEC-β-CD) was studied in this work. The drug encapsulating capacity has been improved by introducing β-CD bound to the PCEC co-polymer. The prepared PCEC-β-CD co-polymers self-assembled in water to form micelles, and underwent a temperature-dependent gel-sol transition, which was in the form of a flowing injectable solution at low temperatures but became a non-flowing gel at around physiological body temperature. Furthermore, a small hydrophobic drug molecule indomethacin (IND) was successfully encapsulated in PCEC-β-CD micelles by dialysis at a high encapsulation efficiency and drug loading capacity. The IND-loaded micelles (IND-M) exhibited controlled release in vitro. Additionally, a pharmacodynamic study in vivo based on both the carrageenan-induced acute and complete Freund's adjuvant-induced adjuvant arthritis models indicated that sustained therapeutic efficacy could be achieved through subcutaneous injection of IND-loaded micelles. A significant improvement in the anti-inflammatory effect of IND in rats occurred on encapsulation in PCEC-β-CD micelles.

Acid-sensing ion channels (ASICs) are proton-gated cation channels that are predominantly expressed in the nervous system. ASICs are involved in a number of neurological diseases such as pain, ischemic stroke and multiple sclerosis but limited tools are available to target these channels and provide probes for their physiological functions. Here we report that the anti-protozoal diarylamidines, 4',6-diamidino-2-phenylindole (DAPI), diminazene, hydroxystilbamidine (HSB) and pentamidine potently inhibit ASIC currents in primary cultured hippocampal neurons with apparent affinities of 2.8 microM, 0.3 microM, 1.5 microM and 38 microM, respectively. These four compounds (100 microM) failed to block ENaC channels expressed in oocytes. Sub-maximal concentrations of diminazene also strongly accelerated desensitization of ASIC currents in hippocampal neurons. Diminazene blocked ASIC1a, -1b -2a, and -3 currents expressed in CHO cells with a rank order of potency 1b > 3 > 2a >or= 1a. Patchdock computational analysis suggested a binding site of diarylamidines on ASICs. This study indicates diarylamidines constitute a novel class of non-amiloride ASIC blockers and suggests that diarylamidines may be developed as therapeutic agents in treatment of ASIC-involved diseases.

Poly(epsilon-caprolactone)-poly(ethylene glycol) (PCL-PEG) copolymers are important synthetic biomedical materials with amphiphilicity, controlled biodegradability, and great biocompatibility. They have great potential application in the fields of nanotechnology, tissue engineering, pharmaceutics, and medicinal chemistry. This review introduced several aspects of PCL-PEG copolymers, including synthetic chemistry, PCL-PEG micro/nanoparticles, PCL-PEG hydrogels, and physicochemical and toxicological properties.

Hepatitis B virus X protein (HBx) plays a crucial role in the development of hepatocellular carcinoma (HCC). However, the significance of circulating antibody to hepatitis B virus X antigen (anti-HBx) in sera remains unclear. In the present study, we examined the titers of anti-HBx (IgG) in the sera from 173 patients with chronic hepatitis B (CHB), 106 liver cirrhosis (LC), and 61 HCC by enzyme-linked immunosorbent assay (ELISA), respectively. Our data showed that the positive rates of anti-HBx were higher in sera of LC (40.6%) and HCC (34.4%) than those of CHB (10.4%),P<.05. In all 40 patients with anti-HBx+ out of 340 patients, 39 (97.5%) were HBsAg/HBeAg/anti-HBc+ and 1 (2.5%) was anti-HBs+ (P<.01), suggesting that anti-HBx in sera is a marker of HBV replication rather than a protective antibody. Thus, our findings reveal that circulating anti-HBx in sera is one of the markers of development of LC and HCC mediated by HBV.

Copolymeric nanocarriers assembled by amphiphilic polyphosphazene bearing poly(N-isopropylacrylamide) (PNIPAAm) and ethyl glycinate (EtGly) as substitutes, were investigated as drug vehicles for indomethacin (IND). The physicochemical characteristics of the novel nanocontainers were studied, including lower critical solution temperature (LCST), critical micelle concentration (CMC) and drug loading capacity. LCST measurements revealed that copolymer is more sensitive to the introduction of salts into aqueous solution compared with homopolymer. A significant decrease in CMC was observed when the temperature increased above LCST. As evidenced by transmission electron microscopy (TEM) measurement, morphological transformation from multicompartment into spherical nanoparticles was observed when nanocarriers with higher IND content were concerned. In vitro release tests suggested that IND-loaded nanocontainers exhibited pH dependent release profiles. In vivo pharmacokinetic study after subcutaneous administration provided a relatively sustained release behavior. Additionally, compared with free drug solution at the same dose, IND concentration in rat plasma showed a prolonged retention in experimental group treated with IND-loaded micelles. In vivo pharmacodynamic study based on both carrageenan-induced acute and complete Freund's adjuvant (CFA) induced adjuvant-arthritis models indicated that sustained therapeutic efficacy could be achieved through intraarticular injection of IND-loaded micelles. Most importantly, local delivery of IND can avoid the severe gastrointestinal stimulation, which is frequently associated with oral administration.

Menghua Gao,1 Yuzhen Xu,1 Liyan Qiu2,3 1College of Pharmaceutical Sciences, 2Ministry of Education (MOE) Key Laboratory of Synthesis and Functionalization, Department of Polymer Science and Engineering, ZhejiangUniversity, Hangzhou, 3Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, People’s Republic of China Abstract: A novel composite liposomal system co-encapsulating paclitaxel (PTX) with chloroquine phosphate (CQ) was designed for treating PTX-resistant carcinoma. It was confirmed that liposomal CQ can sensitize PTX by means of autophagy inhibition and competitively binding with multidrug-resistance transporters. Furthermore, according to the in vitro cytotoxicity and apoptosis assay, real-time observation of cellular uptake, and in vivo tissue distribution study, co-encapsulation of PTX and CQ in liposomes was validated as superior to the mixture of PTX liposome plus CQ liposome due to the simultaneous delivery and synergetic effect of the two drugs. Consequently, this composite liposome achieved significantly stronger anticancer efficacy in vivo than the PTX liposome plus CQ liposome mixture. This study helps to guide and enlighten ongoing and future clinical trials about the optimal administration modes for drug combination therapy. Keywords: paclitaxel, chloroquine, liposome, drug resistance, combination therapy

Yuzhen Xu,1 Liyan Qiu2 1College of Pharmaceutical Sciences, 2Ministry of Education Key Laboratory of Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, People’s Republic of China Abstract: The use of vincristine (VCR) to treat cancer has been limited by its dose-dependent toxicity and development of drug resistance after repeated administrations. In this study, we investigated the mechanism by which quinine hydrochloride (QN) acts as a sensitizer for VCR. Our experiments used three kinds of multidrug-resistant cancer cells and demonstrated that QN worked by inducing intracellular depletion of adenosine triphosphate, increasing adenosine triphosphatase activity, and decreasing P-glycoprotein expression. Based on these results, we designed and prepared a VCR and QN codelivery liposome (VQL) and investigated the effect of coencapsulated QN on the in vitro cytotoxicity of VCR in cells and three-dimensional multicellular tumor spheroids. The antitumor effects of the formulation were also evaluated in multidrug-resistant tumor-bearing mice. The results of this in vivo study indicated that VQL could reverse VCR resistance. In addition, it reduced tumor volume 5.4-fold when compared with other test groups. The data suggest that VQL could be a promising nanoscaled therapeutic agent to overcome multidrug resistance, and may have important clinical implications for the treatment of cancer. Keywords: vincristine, quinine, combination therapy, liposome, multidrug resistance reversal, P-glycoprotein&nbsp

The interaction of 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and a poorly water-soluble flavonoid, baicalein (Ba), chemically 5,6,7-trihydroxy flavone in solution and solid-state was studied. Ba/HP-beta-CD solid systems were prepared by freeze-drying method. The formation of Ba/HP-beta-CD complex in aqueous solution was demonstrated by UV spectroscopy, while Ba/HP-beta-CD co-lyophilized product was characterized by differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). Through complexation with HP-beta-CD, the solubility of Ba in neutral aqueous solution was improved significantly. The phase-solubility profile was AP-type, indicating the formation of higher-order complexes or complex aggregates. Ba/HP-beta-CD solid powders were amorphous and show a significantly improved dissolution rate in comparison with free Ba. Comparison of the pharmacokinetics between Ba/HP-beta-CD co-lyophilized product and free Ba was also performed in rats. The concentration of Ba and its mainly conjugated metabolite, 7-O-glucuronide of baicalein (BG) in rat plasma was determined by HPLC method. The in vivo results show that Ba/HP-beta-CD co-lyophilized product exhibits the similar pharmacokinetics as that of free Ba after intravenous administration. Ba/HP-beta-CD co-lyophilized product displays earlier tmax and higher Cmax of BG than free Ba after oral dosing. By comparing the AUC0-infinity of BG between oral dosing, the relative bioavailability of Ba/HP-beta-CD co-lyophilized product to free Ba was 165.0%, which highlighted the evidence of significantly improved bioavailability of formulation of Ba with HP-beta-CD.

Sendai virosomes can deliver encapsulated contents into the cytoplasm directly in a virus fusion-dependent manner. In this paper, Sendai virosomes-formulated melanoma vaccine was constructed and its anti-tumor effects were investigated. The melanoma vaccine was prepared by encapsulating mixture antigen into the Sendai virosomes. The antigen, mixture proteins were extracted from B 16 melanoma cells. The cytotoxic T lymphocyte (CTL) response level was evaluated by 51 Cr release method, and the change of CD4 + and CD8 + expression as well as the concentration of IgG in serum of immunized mice was measured. The results showed that Sendai virosomes-formulated melanoma vaccine can effectively elicit not only systemic immune response but also strong CTL response. Sendai virosomes can be used as an effective vector for use in anti-tumor vaccine therapy.

The degradation performance and tissue compatibility of polyphosphazene/polyester or polyanhydride (PGP/PLGA or PGP/PSTP) blend films were investigated in mice. The results showed that the blend degradation rate could be regulated by adjusting PLGA or PSTP content in the blends. For example, the weight loss of PGP/PLGA (70:30 by wt) film was 68.4% after 55 days, whereas that of PGP/PSTP (70:30 by wt) was 88.5% only after 12 days. Also the mechanisms for in vivo degradation of blends of PGP/PLGA and PGP/PSTP were hydrolysed enzymatically and non-enzymatically, respectively. The tissue compatibility of PGP/PLGA was better than that of PGP/PSTP, and an increase of the percentage of PGP in PGP/PSTP blends would help improve the tissue compatibility. These findings suggested that polyphosphazene blends be potential materials applied in medical field.