Systematic evaluation of multifunctional paclitaxel-loaded polymeric mixed micelles as a potential anticancer remedy to overcome multidrug resistance

Overcoming colloidal nanoparticle aggregation in biological milieu for cancer therapeutic delivery: Perspectives of materials and particle design

Nanoparticles as cancer therapeutic carrier fail in clinical translation due to complex biological environments in vivo consisting of electrolytes and proteins which render nanoparticle aggregation and unable to reach action site. This review identifies the desirable characteristics of nanoparticles and their constituent materials that prevent aggregation from site of administration (oral, lung, injection) to target site. Oral nanoparticles should ideally be 75-100 nm whereas the size of pulmonary nanoparticles minimally affects their aggregation. Nanoparticles generally should carry excess negative surface charges particularly in fasting state and exert steric hindrance through surface decoration with citrate, anionic surfactants and large polymeric chains (polyethylene glycol and polyvinylpyrrolidone) to prevent aggregation. Anionic as well as cationic nanoparticles are both predisposed to protein corona formation as a function of biological protein isoelectric points. Their nanoparticulate surface composition as such should confer hydrophilicity or steric hindrance to evade protein corona formation or its formation should translate into steric hindrance or surface negative charges to prevent further aggregation. Unexpectedly, smaller and cationic nanoparticles are less prone to aggregation at cancer cell interface favoring endocytosis whereas aggregation is essential to enable nanoparticles retention and subsequent cancer cell uptake in tumor microenvironment. Present studies are largely conducted in vitro with simplified simulated biological media. Future aggregation assessment of nanoparticles in biological fluids that mimic that of patients is imperative to address conflicting materials and designs required as a function of body sites in order to realize the future clinical benefits.

Enhancing the antitumor immunosurveillance of PD-L1-targeted gene therapy for metastatic melanoma using cationized Panax Notoginseng polysaccharide

Improved curative effects with reduced toxicity has always been the ultimate goal of gene delivery vectors for tumor immunotherapy. Panax notoginseng polysaccharide (PNP), a natural plant-derived macromolecule, not only has antitumor immune activity but also has the typical structural characteristics useful for gene delivery. In this work, positively charged polyethyleneimine (PEI) was directly grafted to the backbone of PNP to induced its charge reversal and generate a functional gene vector (PNP-PEI). Moreover, a short hairpin RNA targeting the programmed death-ligand 1 (PD-L1) was loaded into PNP-PEI to generate a potentially therapeutic nanoparticle (PNP-PEI/shPD-L1). In vitro and in vivo experiments demonstrated that PNP-PEI could efficiently carry the therapeutic shPD-L1 into tumor cells and that PNP-PEI/shPD-L1 could significantly inhibit the expression of PD-L1 and growth of B16-F10 cells. Noteworthily, treatment with PNP-PEI reversed the phenotype of macrophages from M2 to M1 subtype and promoted dendritic cell maturation, which encouraged the host immunity and enhanced the therapeutic antitumor effects. In summary, this study describes a PNP-based gene delivery vector and highlights the beneficial immunopotentiating therapeutic outcomes of PNP-PEI for tumor immunotherapy.

Overcoming multidrug resistance through targeting ABC transporters: lessons for drug discovery

INTRODUCTION

The argument around cancer therapy is an old one. Using chemotherapeutic drugs, as one of the most effective strategies in treatment of malignancies, is restricted by various issues that progress during therapy and avoid achieving clinical endpoints. Multidrug resistance (MDR), frequently mediated by ATP-binding cassette (ABC) transporters, is one of the most recognized obstacles in the success of pharmacological anticancer approaches. These transporters efflux diverse drugs to extracellular environment, causing MDR and responsiveness of tumor cells to chemotherapy diminishes.

AREAS COVERED

Several strategies have been used to overcome MDR phenomenon. Succession in this field requires complete knowledge about features and mechanism of ABC transporters. In this review, conventional synthetic and natural inhibitors are discussed first and then novel approaches including RNA, monoclonal antibodies, nanobiotechnology, and structural modification techniques are represented.

EXPERT OPINION

With increasing frequency of MDR in cancer cells, it is essential to develop new drugs to inhibit MDR. Using knowledge acquired about ABC transporter's structure, rational design of inhibitors is possible. Also, some herbal products have shown to be potential lead compounds in drug discovery for reversal of MDR.

Tumor-associated macrophage membrane-camouflaged pH-responsive polymeric micelles for combined cancer chemotherapy-sensitized immunotherapy

The low immunogenicity and tumor immunosuppressive microenvironment (TIM) are two major obstacles for cancer immunotherapy. Synergistically immunogenic cell death induction and tumor-associated macrophages depletion could perfectly overcome this limitation. Herein, a tumor-associated macrophage (TAMs) membrane-camouflaged pH-responsive doxorubicin (DOX) loaded hyaluronic acid (HA)-g-poly (histidine) polymeric micelles (DHP@M2) was fabricated for the first time. DHP@M2 could effectively accumulated into tumor regions via TAMs membrane mediated immune camouflage. In acidic tumor microenvironment, particle size of DHP was enlarged due to decrease hydrophobic interaction of inner core, which caused a "membrane escape effect" to expose inner HA residue. Together high expression of α4β1 integrin, DHP@M2 could reach CD44/VCAM-1 dual-targetability to facilitate intracellular DOX accumulation for efficient ICD induction. Meanwhile, TAMs membrane could absorb colony stimulating factor 1(CSF1) through high expression of its receptor (CSF1R) on TAMs membrane to deplete TAMs in tumor tissues and relieved TIM. This strategy could efficiently induce cytotoxic T lymphocyte (CTLs) infiltration for antitumor immune response and inhibit tumor progression in 4T1 tumor bearing Balb/c mice. Therefore, DHP@M2 is suitable for cancer chemotherapy-sensitized immunotherapy.

Strategies and Mechanism in Reversing Intestinal Drug Efflux in Oral Drug Delivery

Efflux transporters distributed at the apical side of human intestinal epithelial cells actively transport drugs from the enterocytes to the intestinal lumen, which could lead to extremely poor absorption of drugs by oral administration. Typical intestinal efflux transporters involved in oral drug absorption process mainly include P-glycoprotein (P-gp), multidrug resistance proteins (MRPs) and breast cancer resistance protein (BCRP). Drug efflux is one of the most important factors resulting in poor absorption of oral drugs. Caco-2 monolayer and everted gut sac are sued to accurately measure drug efflux in vitro. To reverse intestinal drug efflux and improve absorption of oral drugs, a great deal of functional amphiphilic excipients and inhibitors with the function of suppressing efflux transporters activity are generalized in this review. In addition, different strategies of reducing intestinal drugs efflux such as silencing transporters and the application of excipients and inhibitors are introduced. Ultimately, various nano-formulations of improving oral drug absorption by inhibiting intestinal drug efflux are discussed. In conclusion, this review has significant reference for overcoming intestinal drug efflux and improving oral drug absorption.

Watson-Crick Base Pairing-Inspired Laser/GSH Activatable miRNA-Coordination Polymer Nanoplexes for Combined Cancer Chemo-Immuno-Photothermal Therapy

The tumor immunosuppressive microenvironment (TIM) greatly hindered the efficacy of cancer immunotherapy. Overexpressed indoleamine 2,3-dioxygenase-1 (IDO1) in tumor tissues plays a vital role in TIM generation, and downregulation of IDO1 expression may reverse TIM. Inspired by the Watson-Crick base-pairing rule, a versatile noncationic miRNA vector (miDAC@PDA) is developed for cancer immunotherapy. Doxorubicin (DOX), adenosine triphosphate (ATP), and copper ions (Cu²⁺) are coassembled into coordination polymer nanoparticles (DAC) and bind miRNA via the hydrogen bond interaction (miDAC) between adenine residues (ATP) and uracil residues (miRNA). Polydopamine (PDA) is deposited onto the surface of miDAC for photothermal therapy. miDAC@PDA can efficiently accumulate into tumor tissues for cellular uptake. Under laser irradiation and high intracellular GSH levels, the PDA shell of miDAC@PDA can dissociate from miDAC for miRNA release due to local hyperthermia. Cu²⁺-mediated GSH consumption and intracellular ATP release can amplify the DOX-based immunogenic cell death (ICD) cascade, together with miR-448-mediated IDO1 inhibition, and these versatile nanoplexes will not only restrain primary tumor growth but also display a remarkable abscopal effect on distant tumors. Collectively, our study provides a unique strategy for intracellular gene delivery and an inspirational approach for multimechanism cancer management.

Two-Pronged Anti-Tumor Therapy by a New Polymer-Paclitaxel Conjugate Micelle with an Anti-Multidrug Resistance Effect

Introduction

Cancerous tumors are still a major disease that threatens human life, with tumor multidrug resistance (MDR) being one of the main reasons for the failure of chemotherapy. Thus, reversing tumor MDR has become a research focus of medical scientists.

Methods

Here, a reduction-sensitive polymer prodrug micelle, mPEG-DCA-SS-PTX (PDSP), was manufactured with a new polymer inhibitor of drug resistance as a carrier to overcome MDR and improve the anti-tumor effect of PTX.

Results

The PDSP micelles display good stability, double-responsive drug release, and excellent biocompatibility. The PDSP micelles reduced the cytotoxicity of PTX to normal HL-7702 cells and enhanced that to SMMC-7721 and MCF-7 cells in vitro. Improved sensitivity of A549/ADR to PDSP was also observed in vitro. Furthermore, in vivo experiments show reduced systemic toxicity and enhanced therapeutic efficacy of PTX to H22 subcutaneous tumor-bearing mice.

Conclusion

This work proves that the reduction-sensitive polymer prodrug micelles carried by the new polymer inhibitor can be used as an alternative delivery system to target tumors and reverse MDR for paclitaxel and other tumor-resistant drugs.

Case ReportPaclitaxel-loaded TPGS2k/Gelatin-grafted Cyclodextrin/Hyaluronic acid-grafted Cyclodextrin nanoparticles for oral bioavailability and targeting enhancement

The clinical applications of paclitaxel (PTX), a natural compound with broad-spectrum antitumor effects, have been markedly limited owing to its poor oral bioavailability and lack of targeting ability. Recently, several drug carriers, such as TPGS_2k, gelatin (Gel), cyclodextrin (CD), and hyaluronic acid (HA), have been identified as promising enhancers of drug efficacy. Therefore, Gel-grafted CD (GEL-CD) and HA-grafted CD (HA-CD) were synthesized via grafting, and PTX-loaded TPGS_2k/GEL-CD/HA-CD nanoparticles (TGHC-PTX-NPs) were successfully prepared using the ultrasonic crushing method. The mean particles size, polydispersity index, and Zeta potential of TGHC-PTX-NPs were 253.57 ± 2.64 nm, 0.13 ± 0.03, and 0.087 ± 0.005 mV, respectively. TGHC-PTX-NPs with an encapsulation efficiency of 61.77 ± 0.47% and a loading capacity of 6.86 ± 0.32% appeared round and uniformly dispersed based on transmission electron microscopy. In vitro release data revealed that TGHC-PTX-NPs had good sustained-release properties. Further, TGHC-PTX-NPs had increased the targeted uptake by HeLa cells as HA can specifically bind to the CD44 receptor at the cell surface, and its intestinal absorption is related to caveolin-mediated endocytosis. The pharmacokinetic results indicated that TGHC-PTX-NPs significantly enhanced the absorption of PTX in vivo compared to the PTX suspension, with a relative bioavailability of 227.21%. Such findings indicate the potential of TGHC-PTX-NPs for numerous clinical applications.

Recent advances in polymeric core-shell nanocarriers for targeted delivery of chemotherapeutic drugs

The treatment effect of chemotherapeutics is often impeded by nonspecific biodistribution and limited biocompatibility. Polymeric core-shell nanocarriers (PCS NCs) composed of a polymer core and at least one shell have been widely applied for cancer therapy and have shown great potential in selectively delivering chemotherapeutic drugs to tumor sites. These PCS NCs can effectively ameliorate the delivery efficiency and therapeutic index of anticarcinogens by prolonging drug residence in the bloodstream, enhancing tumor tissue drug penetration, facilitating cellular drug uptake, controlling the spatiotemporal release of payloads, or codelivering two or more bioactive agents. This review summarizes recently published literature on using PCS NCs to transport chemotherapeutic drugs with poor aqueous solubility and discusses their design principles, structural features, functional properties, and potential limitations.

Progress in the study of D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) reversing multidrug resistance

Currently, multidrug resistance (MDR) is one of the major reasons for failure in clinical cancer chemotherapy. Overexpression of the ATP binding cassette (ABC) transporter P-glycoprotein (P-gp), which significantly increases the efflux of anticancer drugs from tumor cells, enhances MDR. In the past few decades, four generations of P-gp inhibitors have appeared. However, they are limited in clinical application due to their severe toxic side effects. As a P-gp inhibitor and carrier for loading chemotherapy agents, TPGS has received increasing attention due to its advantages and unique properties of reversing MDR. TPGS is an amphipathic agent that increases the solubility of most chemotherapy drugs and decreases severe side effects. In addition, TPGS is an excellent carrier with P-gp-inhibiting ability. In this review, we summarize the latest articles on TPGS-based nanodelivery systems to prevent MDR.

T cell membrane cloaking tumor microenvironment-responsive nanoparticles with a smart "membrane escape mechanism" for enhanced immune-chemotherapy of melanoma

The application of combination immune-chemotherapy makes up for the limitation of monotherapy and achieves superior antitumor activity against cancer. However, combinational therapy is always restricted by poor tumor targeted drug delivery efficacy. Herein, novel T cell membrane cloaking tumor microenvironment-responsive nanoparticles (PBA modified T cell membrane cloaking hyaluronic acid (HA)-disulfide bond-vitamin E succinate/curcumin, shortened as RCM@T) were developed. T cell membrane cloaking not only serves as a protection shell for sufficient drug delivery but also acts as a programmed cell death-1(PD-1) "antibody" to selectively bind the PD-L1 of tumor cells. When RCM@T is intravenously administrated into the blood stream, it accumulates at tumor sites and responds to an acidic pH to achieve a "membrane escape effect" and expose the HA residues of RCM for tumor targeted drug delivery. RCM accumulates in the cytoplasm via CD44 receptor mediated endocytosis and intracellularly releases antitumor drug in the intracellular redox microenvironment for tumor chemotherapy. T cell membrane debris targets the PD-L1of tumor cells for tumor immunotherapy, which not only directly kills tumor cells, but also improves the CD8+ T cell level and facilitates effector cytokine release. Taken together, the as-constructed RCM@T creates a new way for the rational design of a drug delivery system via the combination of stimuli-responsive drug release, chemotherapeutical agent delivery and cell membrane based immune checkpoint blockade immunotherapy.

Integrating transcriptomics, proteomics, glycomics and glycoproteomics to characterize paclitaxel resistance in breast cancer cells

Chemoresistance is a major factor driving breast cancer (BC) relapse and the high rates of cancer-related deaths. Aberrant levels of glycans are closely correlated with chemoresistance. The essential functions of glycans in chemoresistance is not systematically studied. In this study, an integrated strategy with a combination of transcriptomics, proteomics, glycomics and glycoproteomics was applied to explore the dysregulation of glycogenes, glycan structures and glycoproteins in chemoresistance of breast cancer cells. In paclitaxel (PTX) resistant MCF7 cells, 19 differentially expressed N-glycan-related proteins were identified, of which MGAT4A was the most significantly down-regulated, consistent with decrease in MGAT4A expression at mRNA level in PTX treated BC cells. Glycomic analysis consistently revealed suppressed levels of multi-antennary branching structures using MALDI-TOF/TOF-MS and lectin microarray. Several target glycoproteins bearing suppressed levels of multi-antennary branching structures were identified, and ERK signaling pathway was strongly suppressed in PTX resistant MCF7 cells. Our findings demonstrated the aberrant levels of multi-antennary branching structures and their target glycoproteins on PTX resistance. Systematically integrative multi-omic analysis is expected to facilitate the discovery of the aberrant glycosyltransferases, N-glycosylation and glycoproteins in tumor progression and chemoresistance. SIGNIFICANCE: An integrated strategy with a combination of transcriptomics, proteomics, glycomics and glycoproteomics is crucial to understand the association between glycans and chemoresistance in BC. In this multi-omic analysis, we identified unique glycan-related protein, glycan and glycoprotein signatures defining PTX chemoresistance in BC. This study might provide valuable information to understand molecular mechanisms underlying chemoresistance in BC.

Nanomedicines for combating multidrug resistance of cancer

Chemotherapy typically involves the use of specific chemodrugs to inhibit the proliferation of cancer cells, but the frequent emergence of a variety of multidrug-resistant cancer cells poses a tremendous threat to our combat against cancer. The fundamental causes of multidrug resistance (MDR) have been studied for decades, and can be generally classified into two types: one is associated with the activation of diverse drug efflux pumps, which are responsible for translocating intracellular drug molecules out of the cells; the other is linked with some non-efflux pump-related mechanisms, such as antiapoptotic defense, enhanced DNA repair ability, and powerful antioxidant systems. To overcome MDR, intense efforts have been made to develop synergistic therapeutic strategies by introducing MDR inhibitors or combining chemotherapy with other therapeutic modalities, such as phototherapy, gene therapy, and gas therapy, in the hope that the drug-resistant cells can be sensitized toward chemotherapeutics. In particular, nanotechnology-based drug delivery platforms have shown the potential to integrate multiple therapeutic agents into one system. In this review, the focus was on the recent development of nanostrategies aiming to enhance the efficiency of chemotherapy and overcome the MDR of cancer in a synergistic manner. Different combinatorial strategies are introduced in detail and the advantages as well as underlying mechanisms of why these strategies can counteract MDR are discussed. This review is expected to shed new light on the design of advanced nanomedicines from the angle of materials and to deepen our understanding of MDR for the development of more effective anticancer strategies. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Emerging nanotaxanes for cancer therapy

The clinical application of taxane (including paclitaxel, docetaxel, and cabazitaxel)-based formulations is significantly impeded by their off-target distribution, unsatisfactory release, and acquired resistance/metastasis. Recent decades have witnessed a dramatic progress in the development of high-efficiency, low-toxicity nanotaxanes via the use of novel biomaterials and nanoparticulate drug delivery systems (nano-DDSs). Thus, in this review, the achievements of nanotaxanes-targeted delivery and stimuli-responsive nano-DDSs-in preclinical or clinical trials have been outlined. Then, emerging nanotherapeutics against tumor resistance and metastasis have been overviewed, with a particular emphasis on synergistic therapy strategies (e.g., combination with surgery, chemotherapy, radiotherapy, biotherapy, immunotherapy, gas therapy, phototherapy, and multitherapy). Finally, the latest oral nanotaxanes have been briefly discussed.

NO-releasing polypeptide nanocomposites reverse cancer multidrug resistance via triple therapies

Multidrug resistance (MDR) induced by the overexpression of P-glycoprotein (P-gp) transporters mainly leads to chemotherapy (CT) failure. Herein, a NIR/pH dual-sensitive charge-reversal polypeptide nanocomposite (PDA-PLC) was developed for co-delivering a nitric oxide (NO) donor and doxorubicin (DOX). Under near-infrared (NIR) irradiation, the released high-concentration of NO gas inhibited the P-gp expression to sensitize the chemotherapeutic medicine DOX and assisted photothermal therapy (PTT) to eradicate cancer cells without skin scarring. Further, the distinctive charge-reversal capacity of PDA-PLC significantly facilitated cellular uptake in the tumor acidic microenvironment (pH 6.8) and enhanced its stability in the physiological environment (pH 7.4). This DOX-loading polypeptide nanocomposite (PDA-PLC/DOX) provides an effective strategy for the PTT-NO-CT triple-combination therapy to overcome MDR STATEMENT OF SIGNIFICANCE: Multidrug resistance (MDR) has been considered to be the paramount factor of chemotherapy (CT) failure in cancer. In this work, an NIR/pH dual-sensitive charge-reversal polypeptide nanomedicine (PDA-PLC/DOX) was developed to overcome MDR through the triple combination therapy of photothermal therapy (PTT), NO gas therapy, and CT. The distinctive charge-reversal capacity of PDA-PLC/DOX significantly facilitated cellular uptake in the tumor acidic microenvironment (pH 6.8) and enhanced its stability in the physiological environment (pH 7.4), while the NIR trigger-released NO gas greatly inhibited the expression of P-gp and synergistically enhanced PTT and CT efficacy. This polypeptide nanocomposite PDA-PLC/DOX provides an effective strategy of using the PTT-NO-CT triple combination therapy with charge-reversal property to completely eradicate the MCF-7/ADR tumor.

Rational Design of Hyaluronic Acid-Based Copolymer-Mixed Micelle in Combination PD-L1 Immune Checkpoint Blockade for Enhanced Chemo-Immunotherapy of Melanoma

The application of combinational therapy breaks the limitation of monotherapy and achieves better clinical benefit for tumor therapy. Herein, a hyaluronic acid/Pluronic F68-based copolymer-mixed micelle was constructed for targeted delivery of chemotherapeutical agent docetaxel (PHDM) in combination with programmed cell death ligand-1(PD-L1) antibody. When PHDM+anti-PDL1 was injected into the blood system, PHDM could accumulate into tumor sites and target tumor cells via CD44-mediated endocytosis and possess tumor chemotherapy. While anti-PDL1 could target PD-L1 protein expressed on surface of tumor cells to the immune checkpoint blockade characteristic for tumor immunotherapy. This strategy could not only directly kill tumor cells but also improve CD8+ T cell level and facilitate effector cytokines release. In conclusion, the rational-designed PHDM+anti-PDL1 therapy strategy creates a new way for tumor immune-chemotherapy.

Chemosensitizing micelles self-assembled from amphiphilic TPGS-indomethacin twin drug for significantly synergetic multidrug resistance reversal

Vitamin E d-ɑ-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS) and indomethacin (IDM) can reverse multidrug resistance (MDR) via inhibiting P-glycoprotein (P-gp) and multidrug resistance associated protein 1 (MRP1) respectively, but their drawbacks in physicochemical properties limit their clinical application. To overcome these defects and enhance MDR reversal, the amphiphilic TPGS-IDM twin drug was successfully synthesized via esterification, and could self-assemble into free and paclitaxel-loaded (PTX-loaded) micelles. The micelles exhibited lower CMC values (5.2 × 10^-5mg/mL), long-term stability in PBS (pH 7.4) for 7 days and SDS solution (5 mg/mL) for 3 days, and effective drug release at esterase/pH 5.0. Moreover, the micelles could down-regulate ATP levels and promote ROS production in MCF-7/ADR via the mitochondrial impairment, therefore achieving MDR reversal and cell apoptosis. Additionally, the PTX-loaded micelles could significantly inhibit the cell proliferation and promote apoptosis for MCF-7/ADR via the synergistic chemosensitizing effect of TPGS and IDM, and synergistic cytotoxic effect of TPGS and PTX. Thus, the chemosensitizing micelles self-assembled from amphiphilic TPGS-indomethacin twin drug have the great potentials for reversing MDR in clinical cancer therapy.

Recent Development of Copolymeric Nano-Drug Delivery System for Paclitaxel

Background:

Paclitaxel (PTX) has been clinically used for several years due to its good therapeutic effect against cancers. Its poor water-solubility, non-selectivity, high cytotoxicity to normal tissue and worse pharmacokinetic property limit its clinical application.

Objective:

To review the recent progress on the PTX delivery systems.

Methods:

In recent years, the copolymeric nano-drug delivery systems for PTX are broadly studied. It mainly includes micelles, nanoparticles, liposomes, complexes, prodrugs and hydrogels, etc. They were developed or further modified with target molecules to investigate the release behavior, targeting to tissues, pharmacokinetic property, anticancer activities and bio-safety of PTX. In the review, we will describe and discuss the recent progress on the nano-drug delivery system for PTX since 2011.

Results:

The water-solubility, selective delivery to cancers, tissue toxicity, controlled release and pharmacokinetic property of PTX are improved by its encapsulation into the nano-drug delivery systems. In addition, its activities against cancer are also comparable or high when compared with the commercial formulation.

Conclusion:

Encapsulating PTX into nano-drug carriers should be helpful to reduce its toxicity to human, keeping or enhancing its activity and improving its pharmacokinetic property.

Novel pH-Sensitive Urushiol-Loaded Polymeric Micelles for Enhanced Anticancer Activity

Purpose

The aim of this study was to develop a means of improving the bioavailability and anticancer activity of urushiol by developing an urushiol-loaded novel tumor-targeted micelle delivery system based on amphiphilic block copolymer poly(ethylene glycol)-b-poly-(β-amino ester) (mPEG-PBAE).

Materials and Methods

We synthesized four different mPEG-PBAE copolymers using mPEG-NH₂ with different molecular weights or hydrophobicity levels. Of these, we selected the mPEG₅₀₀₀-PBAE-C₁₂ polymer and used it to develop an optimized means of preparing urushiol-loaded micelles. Response surface methodology was used to optimize this formulation process. The micellar properties, including particle size, pH sensitivity, drug release dynamics, and critical micelle concentrations, were characterized. We further used the MCF-7 human breast cancer cell line to explore the cytotoxicity of these micelles in vitro and assessed their pharmacokinetics, tissue distribution, and antitumor activity in vivo.

Results

The resulting micelles had a mean particle size of 160.1 nm, a DL value of 23.45%, and an EE value of 80.68%. These micelles were found to release their contents in a pH-sensitive manner in vitro, with drug release being significantly accelerated at pH 5.0 (98.74% in 72 h) without any associated burst release. We found that urushiol-loaded micelles were significantly better at inducing MCF-7 cell cytotoxicity compared with free urushiol, with an IC₅₀ of 1.21 mg/L. When these micelles were administered to tumor model animals in vivo, pharmacokinetic analysis revealed that the total AUC and MRT of these micelles were 2.28- and 2.53-fold higher than that of free urushiol, respectively. Tissue distribution analyses further revealed these micelles to mediate significantly enhanced tumor urushiol accumulation.

Conclusion

The pH-responsive urushiol-loaded micelles described in this study may be ideally suited for clinical use for the treatment of breast cancer.

Recent Advances of D-α-tocopherol Polyethylene Glycol 1000 Succinate Based Stimuli-responsive Nanomedicine for Cancer Treatment

D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) is a pharmaceutical excipient approved by Chinese NMPA and FDA of USA. It's widely applied as a multifunctional drug carrier for nanomedicine. The advantages of TPGS include P-glycoprotein (P-gp) inhibition, penetration promotion, apoptosis induction via mitochondrial-associated apoptotic pathways, multidrug resistant (MDR) reversion, metastasis inhibition and so on. TPGS-based drug delivery systems which are responding to external stimulus can combine the inhibitory functions of TPGS towards P-gp with the environmentally responsive controlled release property and thus exerts a synergistic anti-cancer effect, through increased intracellular drug concentration in tumors cells and well-controlled drug release behavior. In this review, TPGS-based nano-sized delivery systems responsive to different stimuli were summarized and discussed, including pH-responsive, redoxresponsive and multi-responsive systems in various formulations. The achievements, mechanisms and different characteristics of TPGS-based stimuli-responsive drug-delivery systems in tumor therapy were also outlined.

Chemotherapeutic Efficacy Enhancement in P-gp-Overexpressing Cancer Cells by Flavonoid-Loaded Polymeric Micelles

Multidrug resistance is the major problem in cancer treatment nowadays. Compounds from plants are the new targets to solve this problem. Quercetin (QCT), quercetrin (QTR), and rutin (RUT) are potential anticancer flavonoids but their poor water solubility leads to less efficacy. In this study, the polymeric micelles of benzoylated methoxy-poly (ethylene glycol)-b-oligo(ε-caprolactone) or mPEG-b-OCL-Bz loading with the flavonoids were prepared to solve these problems. The flavonoid-loaded micelles showed an average size of 13-20 nm and maximum loading capacity of 35% (w/w). The release of QCT (21%, 3 h) was lower than that of QTR (51%, 3 h) and RUT (58%, 3 h). QCT (free and micelle forms) exhibited significantly higher cytotoxicity against P-glycoprotein-overexpressing leukemia (K562/ADR) cells than QTR and RUT (p < 0.05). The results demonstrated that QCT-loaded micelles effectively reversed cytotoxicity of both doxorubicin (multidrug resistant reversing (δ) values up to 0.71) and daunorubicin (δ values up to 0.74) on K562/ADR cells. It was found that QCT-loaded micelles as well as empty polymeric micelles inhibited P-gp efflux of tetrahydropyranyl Adriamycin. Besides, mitochondrial membrane potential was decreased by QCT (in its free form and micellar formation). Our results suggested that the combination effects of polymeric micelles (inhibiting P-gp efflux) and QCT (interfering mitochondrial membrane potential) might be critical factors contributing to the reversing multidrug resistance of K562/ADR cells by QCT-loaded micelles. We concluded that QCT-loaded mPEG-b-OCL-Bz micelles are the attractive systems for overcoming multidrug-resistant cancer cells.

Dual Receptor-Targeted and Redox-Sensitive Polymeric Micelles Self-Assembled from a Folic Acid-Hyaluronic Acid-SS-Vitamin E Succinate Polymer for Precise Cancer Therapy

Purpose

Poor site-specific delivery and insufficient intracellular drug release in tumors are inherent disadvantages to successful chemotherapy. In this study, an extraordinary polymeric micelle nanoplatform was designed for the efficient delivery of paclitaxel (PTX) by combining dual receptor-mediated active targeting and stimuli response to intracellular reduction potential.

Methods

The dual-targeted redox-sensitive polymer, folic acid-hyaluronic acid-SS-vitamin E succinate (FHSV), was synthesized via an amidation reaction and characterized by ¹H-NMR. Then, PTX-loaded FHSV micelles (PTX/FHSV) were prepared by a dialysis method. The physiochemical properties of the micelles were explored. Moreover, in vitro cytological experiments and in vivo animal studies were carried out to evaluate the antitumor efficacy of polymeric micelles.

Results

The PTX/FHSV micelles exhibited a uniform, near-spherical morphology (148.8 ± 1.4 nm) and a high drug loading capacity (11.28% ± 0.25). Triggered by the high concentration of glutathione, PTX/FHSV micelles could quickly release their loaded drug into the release medium. The in vitro cytological evaluations showed that, compared with Taxol or single receptor-targeted micelles, FHSV micelles yielded higher cellular uptake by the dual receptor-mediated endocytosis pathway, thus leading to significantly superior cytotoxicity and apoptosis in tumor cells but less cytotoxicity in normal cells. More importantly, in the in vivo antitumor experiments, PTX/FHSV micelles exhibited enhanced tumor accumulation and produced remarkable tumor growth inhibition with minimal systemic toxicity.

Conclusion

Our results suggest that this well-designed FHSV polymer has promising potential for use as a vehicle of chemotherapeutic drugs for precise cancer therapy.

Combination Therapy of Doxorubicin and Quercetin on Multidrug-Resistant Breast Cancer and Their Sequential Delivery by Reduction-Sensitive Hyaluronic Acid-Based Conjugate/d-α-Tocopheryl Poly(ethylene glycol) 1000 Succinate Mixed Micelles

The therapeutic efficacy of chemotherapy in many types of hematological malignancies and solid tumors is dramatically hindered by multidrug resistance (MDR). This work presents a combination strategy of pretreatment of MDA-MB-231/MDR1 cells with quercetin (QU) followed by doxorubicin (DOX) to overcome MDR, which can be delivered by mixed micelles composed of the reduction-sensitive hyaluronic acid-based conjugate and d-α-tocopheryl poly(ethylene glycol) 1000 succinate. The combination strategy can enhance the cytotoxicity of DOX on MDA-MB-231/MDR1 cells by increasing intracellular DOX accumulation and facilitating DOX-induced apoptosis. The probable MDR reversal mechanisms are that the pretreatment cells with QU-loaded mixed micelles downregulate P-glycoprotein expression to decrease DOX efflux as well as initiate mitochondria-dependent apoptotic pathways to accelerate DOX-induced apoptosis. In addition, this combination strategy can not only potentiate in vivo tumor-targeting efficiency but also enhance the antitumor effect in MDA-MB-231/MDR1-bearing nude mice without toxicity or side effects. This research suggests that the co-administration of natural compounds and chemotherapeutic drugs could be an effective strategy to overcome tumor MDR, which deserves further exploration.

Stimuli-responsive release and efficient siRNA delivery in non-small cell lung cancer by a poly(l-histidine)-based multifunctional nanoplatform

Small interfering RNA (siRNA) has extensive potential for the treatment of non-small cell lung cancer (NSCLC). While both cationic lipids and polymers have demonstrated promise to facilitate siRNA encapsulation, they can also hamper cytosolic siRNA release and induce severe cytotoxicity. To address these issues, a unique polymer hybrid nanoparticle (NP) nanoplatform was developed for multistage siRNA delivery based on both pH-responsive and endo/lysosomal escape characteristics, which was formed via a combination of an electrostatic interactions between the copolymer methoxy poly(ethylene glycol)-poly(l-histidine)-poly(sulfadimethoxine) (mPEG-PHis-PSD, shortened to PHD), dendritic poly-l-lysine (PLL) and PLK1 siRNA (shortened to siPLK1). The biological composition of the proton sponge effect polymer of the PHis chain, which was in position to make efficient endo/lysosomal escape, and the pH-responsive polymer of the PSD fragment, which could accelerate the release of siPLK1. In the present study, the NP illustrated excellent physiochemical properties and rapid endo/lysosomal escape in vitro. Besides this, compared with the PD/PLL/siRNA formulation, the PHD/PLL/siRNA NP indicated higher cellular uptake, and higher cell cytotoxicity in vitro. The in vivo results demonstrated that the PHD/PLL/siRNA NP exhibited the strongest tumor growth inhibition rate and ideal safety compared with the control and other siPLK1-treated formulations, which can be mainly attributed to pH-induced instantaneous dissociation and efficient endo/lysosomal escape arising from the PHD copolymer. Consequently, the above evidence indicates that the PHD/PLL/siRNA NP is a favorable gene delivery system and provides a potential strategy for siRNA delivery.

Doxorubicin-Loaded Carbon Dots Lipid-Coated Calcium Phosphate Nanoparticles for Visual Targeted Delivery and Therapy of Tumor

Background

Carbon dots (CDs) have attracted extensive attention in recent years because of their high biocompatibility and unique optical property. But they could not be well applied in the drug delivery system to enable distribution in tumor sites with their low pH sensitivity. They are barriers for drug delivery. CDs as an imaging proper were conjugated with doxorubicin (DOX) lipid-coated calcium phosphate (LCP) nanoparticle, for a pH-sensitive nanocarrier and delivery of the antitumor drugs.

Materials and Methods

CDs were prepared by one-step hydrothermal treatment of citric acid and ethylenediamine. The nanoparticles were simply prepared by using microemulsion technology to form calcium phosphate (CaP) core and further coated with cationic lipids.

Results

The structure was characterized by FTIR, XRD and TEM. In vitro release study revealed that DOX-CDs@LCP was pH dependent. The cytotoxicity assay demonstrated that it exhibited enhanced efficiency compared to the control group (DOX-CDs), but weaker than free DOX. The cellular uptake revealed that these pH-sensitive nanoparticles could be taken up effectively and deliver DOX into the cytoplasm to reach antitumor effect. The fluorescence imaging indicated that DOX-CDs@LCP mostly distributed in the tumor region due to the enhanced permeability and retention effect (EPR) to reduce its systematical toxicity. Importantly, an antitumor activity study demonstrated that the DOX-CDs@LCP nanoparticles had higher antitumor activity than any other groups and lower toxicity. The results showed that LCP could significantly promote the release in tumor microenvironment due to pH-response. The DOX-CDs could enhance load capacity and reduce drug premature releasing; real-time tracking of efficacy as confocal imaging contrast agent. Thus, DOX-CDs@LCP had antitumor capacity and lower systematic toxicity in tumor therapy.

Conclusion

DOX-CDs@LCP were proven as a promising tumor pH-sensitive and imaging-guided drug delivery system for liver cancer chemotherapy.

A siramesine-loaded metal organic framework nanoplatform for overcoming multidrug resistance with efficient cancer cell targeting

ZIF-8@Sira/FA induces the cancer cells apoptosis and then eliminates cancer cells from the inside through the lysosomal death pathway.

Near-infrared light switching nitric oxide nanoemitter for triple-combination therapy of multidrug resistant cancer

The multidrug resistance (MDR) of tumor cells often leads to the failure of chemotherapy against cancer. It is urgently needed to develop a safe and effective strategy of overcoming MDR for enhancing chemotherapy efficiency. In this work, one type of new folic acid-polyethylene glycol (FA-PEG) modified polydopamine nanoparticles (FAPPs) was synthesized for gas/chemo/photothermal triple-combination therapy of multidrug resistant cancer. The nanoparticles loaded nitric oxide (NO) donor act as a NO nanoemitter to generate NO via a NIR light irradiation switch, which has a great capacity of reversing MDR via inhibiting the overexpression of P-glycoprotein (P-gp) and cell respiration with the reduction of both the adenosine triphosphate (ATP) content and mitochondrial membrane potential (ΔΨ_m) in MDR tumor cells. Moreover, the amount of generated NO can be regulated by changing the action time of the nanoparticles. After that, the nanoparticles loaded chemotherapeutic agent (DOX) act as a photothermal-chemotherapy nanomedicine, which can release DOX with a high concentration in tumor cell for chemotherapy and simultaneously produce a large amount of heat for photothermal therapy under NIR irradiation. Finally, the gas/chemo/photothermal triple-combination therapy with the nanomedicines displays an excellent therapeutic efficacy in nude mice bearing MDR tumors. STATEMENT OF SIGNIFICANCE: The multidrug resistance (MDR) of tumor cells frequently leads to the failure of chemotherapy against cancer. It is urgently needed to develop a safe and effective strategy of overcoming MDR for enhancing chemotherapy efficiency. In this paper, a NIR light switching nitric oxide nanoemitter is successfully developed for gas/chemo/photothermal triple-combination therapy of multidrug resistant cancer. The controllably generated NO under NIR irradiation can effectively reverse multidrug resistance by inhibiting the overexpression of P-gp and cell respiration, significantly enhancing the chemotherapeutic agent concentration in tumor cells, and simultaneously a large amount of heat is produced for photothermal therapy.

The dextrans as vehicles for gene and drug delivery

Dextran has become a hot research topic in drug vehicle material because of its biodegradable, nonspecific cell adhesion, resistance to protein adsorption, low price and ease of structural modification. The fate and changes of dextran in vivo are not fully understood. It is helpful to guide the design and modification of dextran drug vehicles to clarify the changes in the morphology, metabolism and function of drug targets. With the deep understanding of dextran and the emergence of new functional dextran derivatives, its application in nanodrug delivery systems will be more and more, clinically applicable delivery systems may also be available.

Dual-Responsive Size-Shrinking Nanocluster with Hierarchical Disassembly Capability for Improved Tumor Penetration and Therapeutic Efficacy

It is generally known that, for nanoparticles in cancer therapy, sufficient tumor penetration needs a minor particle size, while long in vivo circulation time needs a larger particle size. It is hard to balance them because they are standing on either side of a seesaw. To address these two different requirements, a dual-responsive size-shrinking nanocluster can self-adaptively respond to a complicated tumor microenvironment and transform its particulate property to overcome sequential in vivo barriers and reach a preferable antitumor activity. The nanocluster (RPSPT@SNCs) could preferentially accumulate into tumor tissue and dissociate under extracellular matrix metalloproteinase-2 (MMP-2) to release small-sized micelle formulations (RPSPTs). RPSPT possesses favorable tumor penetration and tumor targeting capability to deliver the antitumor agent paclitaxel (PTX) into deep regions of solid tumor. The intracellular redox microenvironment can also accelerate drug accumulation. The prepared RPSPT@SNCs possesses enhanced cell cytotoxicity and tumor penetration capability on MCF-7 cells and a favorable antitumor activity on the xenograft tumor mouse model.

Polymeric Micelles of Modified Chitosan Block Copolymer as Nanocarrier for Delivery of Paclitaxel

Background:

Polymeric micelles are being used as successful nanocarriers for the delivery of diverse drug molecules due to properties like solubilization, selective targeting, P-glycoprotein inhibition, altered drug internalization route and subcellular localization etc.

Objective:

The present investigation was planned to prepare and characterize novel polymeric micelles derived from self assembly of amphiphilic chitosan-bile salt derivative (CS-mPEG-DA) as nanocarrier and evaluate their potential in delivery of an anticancer drug, paclitaxel.

Method:

Paclitaxel, a diterpenoid compound, useful in clinical treatment of several solid tumors such as ovarian cancer, breast cancer and lung cancer suffers from limitations like low aqueous solubility and bioavailability and subsequently was used as the model drug.

Results:

Paclitaxel was successfully incorporated into polymeric micelles using dialysis and emulsion method with encapsulation efficiency up to 95% having particle size in nanometer range (<200 nm). Paclitaxel loaded micelles were found to release the drug in a sustained manner up to 96 h in PBS containing 0.1% (w/v) tween 80 at 37&#176;C. The micelles powders subjected to stability studies for a period of 90 days were found to be stable at 4 &#177; 2&#176;C with respect to particle size and drug content. In vivo cytotoxicity assay confirmed that paclitaxel encapsulated in polymeric micelles showed higher cytotoxicity against cultured MCF-7 breast cancer cells than paclitaxel alone.

Conclusion:

Polymeric micellar systems derived from copolymerization of chitosan exhibit a great potential in successful delivery of poorly water soluble or low bioavailable drugs like paclitaxel.

A dual pH-sensitive liposomal system with charge-reversal and NO generation for overcoming multidrug resistance in cancer

In cancer therapy, chemotherapeutic drugs frequently encounter multidrug resistance (MDR) induced by the overexpression of drug transporters such as P-glycoprotein (P-gp). Herein, in order to overcome MDR and improve the effectiveness of chemotherapy, we developed a novel pH-sensitive charge-reversal and NO generation liposomal system by modifying a pH-sensitive polymer (PEG-PLL-DMA) on the surface of cationic liposomes for delivering a NO donor (DETA NONOate) and a chemotherapy drug (paclitaxel, PTX) into MDR cells. The proposed liposomal system (PTX/NO/DMA-L) exhibited a distinctive charge-reversal capacity, which was negatively charged under physiological conditions (pH 7.4) but could reverse to positive charge in a tumor microenvironment (pH 6.5) due to the cleavable amide linkages formed between PEG-PLL and DMA, leading to the improvement of cell uptake. Once arrived in the endosomes and lysosomes (pH 5.0), DETA NONOate was triggered to decompose and release NO, which further promoted the quick release of PTX and inhibited the P-gp mediated efflux. The charge-reversal, NO generation and NO-triggered rapid release of drugs could significantly increase the accumulation of PTX in tumors and eventually improve the antitumor efficacy. These results indicate that this dual pH-sensitive liposomal system is a highly promising approach for chemotherapy and may pave a new avenue for overcoming MDR in cancer.

Hydrophobic Nature of Methacrylate-POSS in Combination with 2-(Methacryloyloxy)ethyl Phosphorylcholine for Enhanced Solubility and Controlled Release of Paclitaxel

Amphiphilic copolymers consisting of 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) and hydrophobic monomers are known as biomaterials for the administration of poorly water-soluble drugs such as paclitaxel (PTX). However, the hydrophobic monomers to be copolymerized with MPC have not been optimized for PTX solubilization and its dosage forms. Here, we show the enhanced PTX solubility by only an MPC-based amphiphilic copolymer using a polyhedral oligomeric silsesquioxane (POSS) methacrylate (MA) bearing an ethyl (C₂H₅) group as a vertex group. MPC was copolymerized with POSS methacrylates bearing different vertex groups of ethyl (C₂H₅), hexyl (C₆H₁₃), and octyl (C₈H₁₇) via radical polymerization. We found that the strong interaction between C₂H₅-POSS and PTX contributed to the slow release of PTX without any burst release. The C₂H₅-POSS-MA MPC copolymer was internalized into the cultured HeLa cells, which was confirmed by using a fluorescein-4-isothiocyanate (FITC)-labeled PTX, and the PTX-dissolved copolymer induced cell death. We anticipate that the C₂H₅-POSS-MA MPC copolymer is a good solubilizer bearing a controlled release function for PTX.

A Smart pH-Sensitive Delivery System for Enhanced Anticancer Efficacy via Paclitaxel Endosomal Escape

Micelles are highly attractive nano-drug delivery systems for targeted cancer therapy. While they have been demonstrated to significantly alleviate the side-effects of their cargo drugs, the therapy outcomes are usually suboptimal partially due to ineffective drug release and endosome entrapment. Stimulus-responsive nanoparticles have allowed controlled drug release in a smart fashion, and we want to use this concept to design novel micelles. Herein, we reported pH-sensitive paclitaxel (PTX)-loaded poly (ethylene glycol)-phenylhydrazone-dilaurate (PEG-BHyd-dC12) micelles (PEG-BHyd-dC12/PTX). The micelles were spherical, with an average particle size of ∼135 nm and a uniform size distribution. The pH-responsive properties of the micelles were certified by both colloidal stability and drug release profile, where the particle size was strikingly increased accompanied by faster drug release as pH decreased from 7.4 to 5.5. As a result, the micelles exhibited much stronger cytotoxicity than the pH-insensitive counterpart micelles against various types of cancer cells due to the hydrolysis of the building block polymers and subsequent rapid PTX release. Overall, these results demonstrate that the PEG-BHyd-dC12 micelle is a promising drug delivery system for cancer therapy.

pH-responsive hybrid nanoparticle with enhanced dissociation characteristic for siRNA delivery

INTRODUCTION

Specific polo-like kinase (PLK1) silencing with small interface RNA (siRNA) may be an effective approach for PLK1-overexpressed lung cancer. However, low siRNA concentration into cytoplasm of tumor tissue severely limits its application.

MATERIALS AND METHODS

In this study, a novel triblock copolymer methoxy poly(ethylene glycol)-poly(histidine)-poly(sulfadimethoxine) (mPEG-PHis-PSD, shorten as PHD) was synthesized and used to construct novel nonviral gene vector with cationic liposomes.

RESULTS

The resulting hybrid nanoparticles (PHD/LR) loaded with siPLK1 possessed excellent physiochemical properties. In vitro study indicated that PHD/LR could be efficiently internalized into human lung adenocarcinoma A549 cells and downregulated PLK1 protein expression to induce cell apoptosis, which was attributed to pH-induced instantaneous dissociation, efficient endo/lysosomal escape arose from PHD copolymer. Furthermore, in vivo antitumor activity demonstrated that PHD/LR could efficiently accumulated into tumor tissue and silenced PLK1 expression to possess antitumor activity.

CONCLUSION

Taken all these together, PHD/LR was expected to be a suitable carrier for specific delivering siRNA for lung cancer therapy.

Mitochondria-targeted delivery of doxorubicin to enhance antitumor activity with HER-2 peptide-mediated multifunctional pH-sensitive DQAsomes

Introduction

Multidrug resistance (MDR) of breast cancer is the major challenge to successful chemotherapy while mitochondria-targeting therapy was a promising strategy to overcome MDR.

Materials and methods

In this study, HER-2 peptide-PEG₂₀₀₀-Schiff base-cholesterol (HPSC) derivate was synthesized successfully and incorporated it on the surface of the doxorubicin (DOX)-loaded dequalinium (DQA) chloride vesicle (HPS-DQAsomes) to treat drug-resistant breast cancer. Evaluations were performed using human breast cancer cell and DOX-resistant breast cancer cell lines (MCF-7 and MCF-7/ADR).

Results

The particle size of HPS-DQAsomes was ~110 nm with spherical shape. In vitro cytotoxicity assay indicated that HPS-DQAsomes could increase the cytotoxicity against MCF-7/ADR cell line. Cellular uptake and mitochondria-targeting assay demonstrated that HPS-DQAsomes could target delivering therapeutical agent to mitochondria and inducing mitochondria-driven apoptosis process. In vivo antitumor assay suggested that HPS-DQAsomes could reach favorable antitumor activity due to both tumor targetability and sub-organelles’ targetability. Histological assay also indicated that HPS-DQAsomes showed a strong apoptosis-inducing effect. No obvious systematic toxicity of HPS-DQAsomes could be observed.

Conclusion

In summary, multifunctional HPS-DQAsomes provide a novel and versatile approach for overcoming MDR via mitochondrial pathway in cancer treatment.

A vascular disrupting agent overcomes tumor multidrug resistance by skewing macrophage polarity toward the M1 phenotype

Multidrug resistance (MDR) mediated by ATP-binding cassette (ABC) transporters is the major obstacle for chemotherapeutic success. Although attempts have been made to circumvent ABC transporter-mediated MDR in past decades, there is still no effective agent in clinic. Here, we identified a vascular disrupting agent, Z-GP-DAVLBH, that significantly inhibited the growth of multidrug-resistant human hepatoma HepG2/ADM and human breast cancer MCF-7/ADR tumor xenografts, although these cells were insensitive to Z-GP-DAVLBH in vitro. Z-GP-DAVLBH increased the secretion of granulocyte-macrophage colony-stimulating factor in tumor tissues and serum of tumor-bearing mice to skew tumor-associated macrophages from the pro-tumor M2 phenotype to the antitumor M1 phenotype, thereby contributing to the induction of HepG2/ADM and MCF-7/ADR cell apoptosis. Our findings shed new light on the underlying mechanisms of VDAs in the treatment of drug-resistant tumors and provide strong evidence that Z-GP-DAVLBH should be a promising agent for overcoming MDR.

Theranostic system based on NaY(Mn)F4:Yb/Er upconversion nanoparticles with multi-drug resistance reversing ability

An innovative theranostic system (D-UNT) for MDR tumors diagnosis and therapy based on the red emitter NaY(Mn)F₄:Yb/Er with optimized luminescence was developed.

A cyclo-trimer of acetonitrile combining fluorescent property with ability to induce osteogenesis and its potential as multifunctional biomaterial

A biomaterial combining fluorescent property with ability to induce osteogenesis can serve as an ideal multifunctional scaffold in bone tissue engineering. However, the frequently used fluorescent agents can only serve as imaging probes. The polymer or oligomer with a conjugated system containing nitrogen atoms will fulfill these criteria. In this study, a cyclo-trimer of acetonitrile is synthesized using a facile method, which is proved to be 4-amino-2,6-dimethylpyrimidine. The cyclo-trimer of acetonitrile demonstrates strong intrinsic photoluminescence and has the potential for in vivo imaging. The cyclo-trimer of acetonitrile shows no toxicity both in vitro and in vivo. Moreover, the cyclo-trimer of acetonitrile significantly promotes the osteogenesis of SaOS-2 cells by improving alkaline phosphatase activity, collagen type I and osteocalcin expression, as well as expressions of osteoblastic genes, and enhances the matrix mineralization of rBMSCs. Thus, the cyclo-trimer of acetonitrile synthesized in present study illustrates the employment of this kind multifunctional biomaterial in bone tissue engineering and may offer great potential in biomedical applications where bioimaging and osteogenesis are both required.

STATEMENT OF SIGNIFICANCE

A conjugated cyclo-trimer of acetonitrile combining intrinsic fluorescent property with ability to induce osteogenesis was reported. Different from the traditional fluorescent dye or quantum dots, which are just "imaging agents", the cyclo-trimer of acetonitrile can serve as a multifunctional biomaterial and offer great potential in biomedical applications where bioimaging and osteogenesis are both required. To our best knowledge, the fluorescent property, especially fluorescent property in vivo and the ability of this molecule to induce osteogenesis have not been reported before. Our work illustrates the employment of this kind multifunctional biomaterial in bone tissue engineering and will highlight the importance of multifunctional biomaterial in biomedical applications.

Polymeric mixed micelles loaded mitoxantrone for overcoming multidrug resistance in breast cancer via photodynamic therapy

Mitoxantrone (MIT) is an anticancer agent with photosensitive properties that is commonly used in various cancers. Multidrug resistance (MDR) effect has been an obstacle to using MIT for cancer therapy. Photochemical internalization, on account of photodynamic therapy, has been applied to improve the therapeutic effect of cancers with MDR effect. In this study, an MIT-poly(ε-caprolactone)-pluronic F68-poly(ε-caprolactone)/poly(d,l-lactide-co-glycolide)–poly(ethylene glycol)–poly(d,l-lactide-co-glycolide) (MIT-PFP/PPP) mixed micelles system was applied to reverse the effect of MDR in MCF-7/ADR cells via photochemical reaction when exposed to near-infrared light. MIT-PFP/PPP mixed micelles showed effective interaction with near-infrared light at the wavelength of 660 nm and exerted great cytotoxicity in MCF-7/ADR cells with irradiation. Furthermore, MIT-PFP/PPP mixed micelles could improve reactive oxygen species (ROS) levels, decrease P-glycoprotein activity, and increase the cellular uptake of drugs with improved intracellular drug concentrations, which induced cell apoptosis in MCF-7/ADR cells under irradiation, despite MDR effect, as indicated by the increased level of cleaved poly ADP-ribose polymerase. These findings suggested that MIT-PFP/PPP mixed micelles may become a promising strategy to effectively reverse the MDR effect via photodynamic therapy in breast cancer.