Biological evaluation of RGDfK-gold nanorod conjugates for prostate cancer treatment

Selective delivery of gold nanorods (GNRs) to sites of prostate tumor angiogenesis is potentially advantageous for localized photothermal therapy. Here, we report the cellular uptake and biodistribution of GNRs surface functionalized with the cyclic RGDfK peptide. The GNRs were synthesized to have a surface plasmon resonance (SPR) peak at 800?nm and grafted with a thiolated poly(ethylene glycol) (PEG) corona with or without RGDfK. The binding and uptake of the targeted (RGDfK) and untargeted GNRs were evaluated in DU145 prostate cancer and human umbilical vein endothelial cells (HUVEC) by high-resolution dark field microscopy, inductively coupled plasma mass spectrometry (ICP-MS), and transmission electron microscopy (TEM). The biodistribution of both GNRs was then evaluated in prostate tumor bearing mice. Targeting of the RGDfK surface-modified GNRs was confirmed in vitro due to selective binding and uptake by endothelial cells. Tumor targeting was not observed in vivo, however, due to fast clearance of the RGDfK-GNRs from the blood. Further modifications of the nanoparticle’s surface properties are needed to enhance localization of the targetable system in sites of tumor angiogenesis.     

Three-step tumor targeting of paclitaxel using biotinylated PLA-PEG nanoparticles and avidin-biotin technology: Formulation development and in vitro anticancer activity

Despite recent advances in cancer therapy, many malignant tumors still lack effective treatment and the prognosis is very poor. Paclitaxel is a potential anticancer drug, but its use is limited by the facts that paclitaxel is a P-gp substrate and its aqueous solubility is poor. In this study, three-step tumor targeting of paclitaxel using biotinylated PLA-PEG nanoparticles and avidin-biotin technology was evaluated in vitro as a way of enhancing delivery of paclitaxel. Paclitaxel was incorporated both in biotinylated (BP) and non-biotinylated (LP) PEG-PLA nanoparticles by the interfacial deposition method. Small (mean size approximately 110nm), spherical and slightly negatively charged (-10mV) BP and LP nanoparticles achieving over 90% paclitaxel incorporation were obtained. The successful biotinylation of nanoparticles was confirmed in a novel streptavidin assay. BP nanoparticles were targeted in vitro to brain tumor (glioma) cells (BT4C) by three-step avidin-biotin technology using transferrin as the targeting ligand. The three-step targeting procedure increased the anti-tumoral activity of paclitaxel when compared to the commercial paclitaxel formulation Taxol((R)) and non-targeted BP and LP nanoparticles. These results indicate that the efficacy of paclitaxel against tumor cells can be increased by this three-step targeting method.     

Degradable and biocompatible nanoparticles decorated with cyclic RGD peptide for efficient drug delivery to hepatoma cells in vitro

Amphiphilic derivatives of poly(benzyl malate) were synthesized and characterized with the aim of being used as degradable and biocompatible building blocks for the design of functional nanoparticles (NPs). An anti-cancer model drug, doxorubicin, has been successfully encapsulated into the prepared NPs and its release profile has been evaluated in water and in culture medium. NPs bearing biotin molecules were prepared either for site-specific drug delivery via the targeting of biotin receptors overexpressed on the surface of several cancer cells, or for grafting biotinylated cyclic RGD peptide onto their surface using the strong and highly specific interactions between biotin and the streptavidin protein. We have shown that this binding did not affect dramatically the physico-chemical properties of the corresponding NPs. Cyclic RGD grafted fluorescent NPs were more efficiently uptaken by the HepaRG hepatoma cells than biotinylated fluorescent NPs. Furthermore, the targeting of HepaRG hepatoma cells with NPs bearing cyclic RGD was very efficient and much weaker for HeLa and HT29 cell lines confirming that cyclic RGD is a suitable targeting agent for liver cells. Our results also provide a new mean for rapid screening of short hepatotropic peptides in order to design NPs showing specific liver targeting properties.     

Noninvasive Monitoring of HPMA Copolymer–RGDfK Conjugates by Magnetic Resonance Imaging

Purpose  To evaluate the tumor targeting potential of N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer–gadolinium(Gd)–RGDfK conjugates by magnetic resonance (MR) T1-mapping. Methods  HPMA copolymers with and without RGDfK were synthesized to incorporate side chains for Gd chelation. The conjugates were characterized by their side-chain contents and r₁ relaxivity. In vitro integrin-binding affinities of polymeric conjugates were assessed via competitive cell binding assays on HUVEC endothelial cells and MDA-MB-231 breast cancer cells. In vivo MR imaging was performed on MDA-MB-231 tumor-bearing SCID mice at different time points using non-targetable and targetable polymers. The specificity of αvβ3 targeting was assessed by using non-paramagnetic targetable polymer to block αvβ3 integrins followed by injection of paramagnetic targetable polymers after 2 h. Results  The polymer conjugates showed relaxivities higher than Gd-DOTA. Endothelial cell binding studies showed that IC₅₀ values for the copolymer with RGDfK binding to αvβ3 integrin-positive HUVEC and MDA-MB-231 cells were similar to that of free peptide. Significantly lower T1 values were observed at the tumor site after 2 h using targetable conjugate (p < 0.012). In vivo blocking study showed significantly higher T1 values (p < 0.045) compared to targetable conjugate. Conclusion  These results demonstrate the potential of this conjugate as an effective targetable MR contrast agent for tumor imaging and therapy monitoring.     

Effect of surface ligand density on cytotoxicity and pharmacokinetic profile of docetaxel loaded liposomes

Various biotin-modified liposomes incorporated with docetaxel (DTX) were prepared to study the effect of surface biotin density on the pharmacokinetic profile of the liposome. Four types of liposomes such as PEG modified liposome (PDL), 0.5% (mol) biotin modified liposome (0.5BDL), 1% (mol) biotin modified liposome (1BDL) and 2% (mol) biotin modified liposome (2BDL) were prepared using thin film dispersion method. The prepared liposomes were characterized by measuring encapsulation efficiency (EE), particle size, Zeta-potential, physical stability and drug release profiles in vitro. MTT assay was performed to elevate the cytotoxicity of liposomes on MCF-7 cells. In vivo evaluation was further performed to investigate the effect of biotin surface density on the pharmacokinetic profiles. All the prepared liposomes exhibited high encapsulation efficiency, small particle size, narrow particle distribution and sustained release profiles in vitro. In MTT assay, 0.5BDL showed largest tumor cell toxicity, compared with DTX solution. All liposomes containing DTX showed prolonged blood circulation in vivo, and 0.5BDL showed the longest circulation time among the biotin modified liposome. Surface modification of liposome had a negative impact on the circulation of liposomes in the blood, which needs to be considered when designing the ligand mediated targeting delivery systems. A proper amount of biotin liposome with 0.5% molar ratio is expected to produce the best anti-tumor effect.     

All-stage targeted therapy for the brain metastasis from triple-negative breast cancer

Brain metastasis is a common and serious complication of breast cancer, which is commonly associated with poor survival and prognosis. In particular, the treatment of brain metastasis from triple-negative breast cancer (BM-TNBC) has to face the distinct therapeutic challenges from tumor heterogeneity, circulating tumor cells (CTCs), blood–brain barrier (BBB) and blood–tumor barrier (BTB), which is in unmet clinical needs. Herein, combining with the advantages of synthetic and natural targeting moieties, we develop a “Y-shaped” peptide pVAP-decorated platelet-hybrid liposome drug delivery system to address the all-stage targeted drug delivery for the whole progression of BM-TNBC. Inherited from the activated platelet, the hybrid liposomes still retain the native affinity toward CTCs. Further, the peptide-mediated targeting to breast cancer cells and transport across BBB/BTB are demonstrated in vitro and in vivo. The resultant delivery platform significantly improves the drug accumulation both in orthotopic breast tumors and brain metastatic lesions, and eventually exhibits an outperformance in the inhibition of BM-TNBC compared with the free drug. Overall, this work provides a promising prospect for the comprehensive treatment of BM-TNBC, which could be generalized to other cell types or used in imaging platforms in the future.     

Intravenous siRNA of Brain Cancer with Receptor Targeting and Avidin–Biotin Technology

Purpose The effective delivery of short interfering RNA (siRNA) to brain following intravenous administration requires the development of a delivery system for transport of the siRNA across the brain capillary endothelial wall, which forms the blood–brain barrier in vivo. Methods siRNA was delivered to brain in vivo with the combined use of a receptor-specific monoclonal antibody delivery system, and avidin–biotin technology. The siRNA was mono-biotinylated on either terminus of the sense strand, in parallel with the production of a conjugate of the targeting MAb and streptavidin. Results Rat glial cells (C6 or RG-2) were permanently transfected with the luciferase gene, and implanted in the brain of adult rats. Following the formation of intra-cranial tumors, the rats were treated with a single intravenous injection of 270 μg/kg of biotinylated siRNA attached to a transferrin receptor antibody via a biotin–streptavidin linker. The intravenous administration of the siRNA caused a 69–81% decrease in luciferase gene expression in the intracranial brain cancer in vivo. Conclusions Brain delivery of siRNA following intravenous administration is possible with siRNAs that are targeted to brain with the combined use of receptor specific antibody delivery systems and avidin–biotin technology.     

Engineering a folic acid-decorated ultrasmall gemcitabine nanocarrier for breast cancer therapy: Dual targeting of tumor cells and tumor-associated macrophages

Combination of passive targeting with active targeting is a promising approach to improve the therapeutic efficacy of nanotherapy. However, most reported polymeric systems have sizes above 100 nm, which limits effective extravasation into tumors that are poorly vascularized and have dense stroma. This will, in turn, limit the overall effectiveness of the subsequent uptake by tumor cells via active targeting. In this study, we combined the passive targeting via ultra-small-sized gemcitabine (GEM)-based nanoparticles (NPs) with the active targeting provided by folic acid (FA) conjugation for enhanced dual targeted delivery to tumor cells and tumor-associated macrophages (TAMs). We developed an FA-modified prodrug carrier based on GEM (PGEM) to load doxorubicin (DOX), for co-delivery of GEM and DOX to tumors. The co-delivery system showed small particle size of ～10 nm in diameter. The ligand-free and FA-targeted micelles showed comparable drug loading efficiency and a sustained DOX release profile. The FA-conjugated micelles effectively increased DOX uptake in cultured KB cancer cells that express a high level of folate receptor (FR), but no obvious increase was observed in 4T1.2 breast cancer cells that have a low-level expression of FR. Interestingly, in vivo, systemic delivery of FA-PGEM/DOX led to enhanced accumulation of the NPs in tumor and drastic reduction of tumor growth in a murine 4T1.2 breast cancer model. Mechanistic study showed that 4T1.2 tumor grown in mice expressed a significantly higher level of FOLR2, which was selectively expressed on TAMs. Thus, targeting of TAM may also contribute to the improved in vivo targeted delivery and therapeutic efficacy.     

Targetable HPMA Copolymer–Aminohexylgeldanamycin Conjugates for Prostate Cancer Therapy

Purpose  This study focuses on the synthesis and characterization of N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer–cyclo-RGD (Arg-Gly-Asp) conjugates for delivery of geldanamycin to prostate tumors. Materials and Methods  HPMA copolymers containing aminohexylgeldanamycin (AH-GDM) with and without the targeting peptide RGDfK were synthesized and characterized. Drug release from copolymers was evaluated using cathepsin B. Competitive binding of copolymer conjugates to α_vβ₃ integrin was evaluated in prostate cancer (PC-3) and endothelial (HUVEC) cell lines and in vitro growth inhibition was assessed. The maximum tolerated dose for single i.v. injections of free drug and the conjugates was established in nude mice. Results  HPMA copolymers containing AH-GDM and RGDfK showed active binding to the α_vβ₃ integrin similar to that of free peptide. Similarly, growth inhibition of cells by conjugates was comparable to that of the free drug. Single intravenous doses of HPMA copolymer–AH-GDM–RGDfK conjugates in mice were tolerated at 80 mg/kg drug equivalent, while free drug caused morbidity at 40 mg/kg. No signs of toxicity were present in mice receiving HPMA copolymer-AH-GDM-RGDfK over the 14-day evaluation period. Conclusion  Results of in vitro activity and in vivo tolerability experiments hold promise for the utility of HPMA copolymer–AH-GDM–RGDfK conjugates for treatment of prostate cancer with greater efficacy and reduced toxicity.     

HPMA-copolymer conjugates targeted to tumor endothelium using synthetic oligopeptides

Synthesis and characterization of N-(2-hydroxypropyl)methacrylamide (HPMA)-copolymer–based drug carriers targeted on specific receptors in the membrane of endothelial cells by oligopeptides (GRGDG, cyclo(RGDfK), and PHSCN) are described in this study. The copolymers containing targeting oligopeptides bound to the polymer via dodeca(ethylene glycol) spacer showed a receptor-specific time-dependent uptake with selected endothelial cell lines. The polymers were labeled with a fluorescent dye to enable monitoring of the interaction of the polymer conjugate with cells using fluorescence microscopy. Cellular uptake and apoptosis induction have been studied in vitro using various cell lines (EA.hy926, 3T3, SW620, and EL4). In vivo accumulation of the conjugate specifically targeted with cyclo(RGDfK) within the tumor vasculature was detected using fluorescence intravital microscopy in mice. The conjugate targeted by cyclo(RGDfK) was accumulated preferentially in the periphery of the growing tumor suggesting that the cyclo(RGDfK) peptide targets the polymer conjugate to the site of neoangiogenesis, rather than to the tumor mass.     

Surface modification of poly(glycolic acid) (PGA) for biomedical applications

The immobilization of biological ligands (such as biotin and peptides) onto biodegradable polymer surfaces, including poly(glycolic acid) (PGA) sutures, is complicated by the absence of functional groups on the polymer backbone. We demonstrate a method for overcoming this problem, by attaching (+)-biotinyl-3,6,9-trioxaundecanediamine to the surface of PGA sutures, which immobilizes the ligand through an amide bond between amine (ligands) and carboxylic acid groups (surface-hydrolyzed PGA sutures). Fluorescence microscopy was used to verify the attachment of the biotin ligand to the surface of the PGA suture after a complexation with fluorescein-conjugated streptavidin. The strategy can be generalized to surface modifications of other biodegradable aliphatic polyesters, which would improve the properties of the polymers in biomedical applications such as active targeting of drugs based on ligand-attached, polymeric drug delivery systems.     

Self-assembled multifunctional nanotheranostics against circulating tumor clusters in metastatic breast cancer

Circulating tumor clusters(CTC) disseminating from the primary tumor are responsible for secondary tumor formation where the conventional treatments such as chemotherapy and radiotherapy does not prevent the metastasis at locally advanced stage of breast cancer. In this study, a smart nanotheranostic system has been developed to track and eliminate the CTCs before it can colonize at a new site,which would reduce metastatic progression and increase the five-year survival rate of the breast cancer...     

PK11195-chitosan-graft-polyethylenimine-modified SPION as a mitochondria-targeting gene carrier

Superparamagnetic iron oxide nanoparticle (SPION) holds great potential as a gene delivery system due to its unique properties, such as good biocompatibility and non-invasive targeting ability. In this study, we modified SPION with chitosan-graft-PEI (CHI-g-PEI) and PK11195, to fabricate a mitochondria-targeting gene carrier, PK-CP-SPION. PK-CP-SPION manifested prominent physicochemical properties for magnetic guided gene delivery, and it could effectively condense and protect DNA at proper weight ratios. The in vitro cytotoxicity of PK-CP-SPIONs was mild. Under an external magnetic field, the transfection efficiency of PK-CP-SPIONs was comparable to PEI 25?K with shorter transfection time. PK11195 facilitated the specific accumulation of PK-CP-SPIONs in mitochondria, leading to the leakage of cytochrome c, the dissipation of mitochondrial membrane potential and subsequently the activation of mitochondria apoptosis pathway. These results indicated that with further development, PK-CP-SPIONs could serve as a multifunctional nanoplatform for magnetic targeting gene delivery and mitochondria-targeting therapy, leading enhanced therapeutic effect towards tumor cells.     

Interesting possibilities to improve the safety and efficacy of ipilimumab (Yervoy)

As predicted, an anti-CTLA-4 mAb (ipilimumab) on binding to T lymphocytes breaks down immune-tolerance. Thereby, it was hoped, tumor-specific-T cells would be freed for a sustained attack on cancer cells. Data on ipilimumab treatment in 1498 patients with advanced melanoma (in 14 phase I-III trials) has shown immune-related adverse events (irAEs) in 64.2% of the patients consistent with tolerance breakdown. However, there is no evidence that the antitumor effects via a CTLA-4 blockade are attributable to T cells specifically targeting tumor cells. In fact, several trials indicate a possible correlation between grade 3 and 4 irAEs with clinical efficacy of ipilimumab; tumor regression may be associated with autoimmunity development. Therefore, we suggest a new treatment paradigm. The non-tumor specific pan-lymphocytic activation should be exploited by a 'pretargeting' approach proven successful in radioimmunodetection and radioimmunotherapy. First, an anti-tumor mAb conjugated with streptavidin (StAv) should be administered to be followed by the delivery of biotin-labeled anti-CTLA-4 mAb. This schedule has the virtue of endowing T cells with the ability to travel to tumor sites without prematurely succumbing to apoptosis, while streptavidin's ultra-high affinity for biotin (K(D), 10?1? M) ensures capturing all T cells binding biotin labeled anti-CTLA-4. Using the law of mass action, we calculated that following administration of ipilimumab at >1 mg/L concentration (～5 mg per patient ～70 kgbw), the immense forces of the immune system liberated by the anti-CTLA-4 antibody blockade would then be focused with laser sharp accuracy on tumor cells without collateral damage to normal host cells.     

Salmonella-mediated blood‒brain barrier penetration,tumor homing and tumor microenvironment regulation for enhanced chemo/bacterial glioma therapy

Chemotherapy is an important adjuvant treatment of glioma, while the efficacy is far from satisfactory, due not only to the biological barriers of blood?brain barrier (BBB) and blood?tumor barrier (BTB) but also to the intrinsic resistance of glioma cells via multiple survival mechanisms such as up-regulation of P-glycoprotein (P-gp). To address these limitations, we report a bacteria-based drug delivery strategy for BBB/BTB transportation, glioma targeting, and chemo-sensitization. Bacteria selectively colonized into hypoxic tumor region and modulated tumor microenvironment, including macrophages repolarization and neutrophils infiltration. Specifically, tumor migration of neutrophils was employed as hitchhiking delivery of doxorubicin (DOX)-loaded bacterial outer membrane vesicles (OMVs/DOX). By virtue of the surface pathogen-associated molecular patterns derived from native bacteria, OMVs/DOX could be selectively recognized by neutrophils, thus facilitating glioma targeted delivery of drug with significantly enhanced tumor accumulation by 18-fold as compared to the classical passive targeting effect. Moreover, the P-gp expression on tumor cells was silenced by bacteria type III secretion effector to sensitize the efficacy of DOX, resulting in complete tumor eradication with 100% survival of all treated mice. In addition, the colonized bacteria were finally cleared by anti-bacterial activity of DOX to minimize the potential infection risk, and cardiotoxicity of DOX was also avoided, achieving excellent compatibility. This work provides an efficient trans-BBB/BTB drug delivery strategy via cell hitchhiking for enhanced glioma therapy.     

Biotin as a masking agent in chorionic gonadotropin assays utilizing biotinylated antibodies

Biotin interference in streptavidin/biotin-based immunoassays has been recently recognized as a confounding factor in clinical settings. Depending on the nature of the assay, the presence of excess biotin in patient samples can cause falsely high or low results. One of the platforms known to be affected, Roche Cobas, is widely used in anti-doping laboratories to test for intact chorionic gonadotropin (hCG) in urine. While biotin levels in blood have been well studied, less is known about urinary biotin due to its limited clinical significance. Having analyzed over 4,000 urine samples, we have established a reference range for urinary biotin with a median concentration of approximately 12 ng/ml. However, a significant number of samples contain much higher amounts, with a maximum approaching 10 μg/ml, suggesting biotin supplementation. Consequently, the tolerance of hCG STAT assay towards biotin was investigated over a wide concentration range. The apparent hCG concentration was found to decrease almost linearly as biotin increased from 100 to 1,000 ng/ml, with only 10% of the expected value reported by the assay as biotin reached 1,000 ng/ml. Further increase of biotin resulted in a progressive, albeit more moderate, decline in measured hCG concentration. To avoid a false negative result in the context of anti-doping analysis, it is highly recommended to monitor biotin in urine and perform diafiltration before hCG measurement in samples with elevated biotin to remove the interference.     

Efficient drug-delivery using magnetic nanoparticles — biodistribution and therapeutic effects in tumour bearing rabbits

To treat tumours efficiently and spare normal tissues, targeted drug delivery is a promising alternative to conventional, systemic administered chemotherapy. Drug-carrying magnetic nanoparticles can be concentrated in tumours by external magnetic fields, preventing the nanomaterial from being cleared by metabolic burden before reaching the tumour. Therefore in Magnetic Drug Targeting (MDT) the favoured mode of application is believed to be intra-arterial. Here, we show that a simple yet versatile magnetic carrier-system (hydrodynamic particles diameter < 200 nm) accumulates the chemotherapeutic drug mitoxantrone efficiently in tumours. With MDT we observed the following drug accumulations relative to the recovery from all investigated tissues: tumour region: 57.2%, liver: 14.4%, kidneys: 15.2%. Systemic intra-venous application revealed different results: tumour region: 0.7%, liver: 14.4 % and kidneys: 77.8%. The therapeutic outcome was demonstrated by complete tumour remissions and a survival probability of 26.7% (P = 0.0075). These results are confirming former pilot experiments and implying a milestone towards clinical studies.From the Clinical EditorThis team of investigators studied drug carrying nanoparticles for magnetic drug targeting (MDT), demonstrating the importance of intra-arterial administration resulting in improved clinical outcomes in the studied animal model compared with intra-venous.     

Drug targeting to the brain using avidin-biotin technology in the mouse; (blood-brain barrier, monoclonal antibody, transferrin receptor, Alzheimer's disease)

A beta1-40 peptide radiopharmaceuticals could be used to image A beta brain amyloid in transgenic mouse models of Alzheimer's disease should the A beta peptide radiopharmaceutical be made transportable through the blood-brain barrier (BBB) in vivo. The present studies used the RI7-217 rat monoclonal antibody to the mouse transferrin receptor as a BBB drug targeting vector for the delivery to brain of A beta1-40 radiolabeled with either 125-Iodine or 111-Indium. The A beta peptide radiopharmaceutical is conjugated to the RI7 MAb using avidin biotin technology, wherein the A beta1-40 peptide radiopharmaceutical is monobiotinylated (bio) and bound to a conjugate of the RI7 MAb and streptavidin (SA). The [125 I]-bio-A beta1-40 or the [111 In]-bio-A beta1-40 either free or bound to the RI7/SA conjugate was injected intravenously into anesthetized adult mice and plasma pharmacokinetics and organ uptake were measured over the next 60 minutes. The A beta1-40 peptide radiopharmaceutical radiolabeled with 111-Indium was the preferred formulation, compared to peptide labeled with 125-Iodine, because there was a greater metabolic stability and reduced artifactual organ uptake of metabolites associated with the use of the 111-Indium nuclide. However, biotinylated A beta1-40 peptide radiopharmaceuticals conjugated to the RI7/SA brain drug targeting system were metabolically unstable in mice in vivo owing to active biotinidase activity. Future work involving brain drug targeting in mice that utilizes avidin biotin technology will need to incorporate biotin analogues that are resistant to biotinidase.     

Cancer-cell-biomimetic nanoparticles systemically eliminate hypoxia tumors by synergistic chemotherapy and checkpoint blockade immunotherapy

Checkpoint blockade-based immunotherapy has shown unprecedented effect in cancer treatments, but its clinical implementation has been restricted by the low host antitumor response rate. Recently, chemotherapy is well recognized to activate the immune system during some chemotherapeutics-mediated tumor eradication. The enhancement of immune response during chemotherapy might further improve the therapeutic efficiency through the synergetic mechanism. Herein, a synergistic antitumor platform (designated as BMS/RA@CC-Liposome) was constructed by utilizing CT26 cancer-cell-biomimetic nanoparticles that combined chemotherapeutic drug (RA-V) and PD-1/PD-L1 blockade inhibitor (BMS-202) to remarkably enhance antitumor immunity. In this study, the cyclopeptide RA-V as chemotherapeutic drugs directly killing tumor cells and BMS-202 as anti-PD agents eliciting antitumor immune responses were co-encapsulated in a pH-sensitive nanosystem. To achieve the cell-specific targeting drug delivery, the combination therapy nanosystem was functionalized with cancer cell membrane camouflage. The biomimetic drug delivery system perfectly disguised as endogenous substances, and realized elongated blood circulation due to anti-phagocytosis capability. Moreover, the BMS/RA@CC-Liposome also achieved the selective targeting of CT26 cells by taking advantage of the inherent homologous adhesion property of tumor cells. The in vitro and in vivo experiments revealed that the BMS/RA@CC-Liposome realized PD-1/PD-L1 blockade-induced immune response, RA-V-induced PD-L1 down-regulation and apoptosis in cancer cells. Such a system combining the advantages of chemotherapy and checkpoint blockade-based immunotherapy to create an immunogenic tumor microenvironment systemically, demonstrated improved therapeutic efficacy against hypoxic tumor cells and offers an alternative strategy based on the immunology of the PD-1/PD-L1 pathway.     

Surface-engineered liposomes for dual-drug delivery targeting strategy against methicillin-resistant Staphylococcus aureus (MRSA)

This study focused on the encapsulation of vancomycin(VAN) into liposomes coated with a red blood cell membrane with a targeting ligand, daptomycin–polyethylene glycol–1,2-distearoyl-sn-glycero-3-phosphoethanolamine, formed by conjugation of DAPT and Nhydroxysuccinimidyl-polyethylene glycol-1,2-distearoyl-sn-glycero-3-phosphoethanolamine.This formulation is capable of providing controlled and targeted drug delivery to the bacterial cytoplasm. We performed MALDI-TOF, NMR and FTIR analyses to conf...