Targeting Carrier Research Articles

Design and synthesis of novel dual-cyclic RGD peptides for αvβ3 integrin targeting

The specific binding of RGD cyclic peptide with integrin αvβ3 attracts great research interest for tumor-targeting drug delivery. Herein, we designed and synthesized a series of dual-ring RGD-peptide derivatives as a drug carrier for αvβ3 targeting. Three novel peptides showed excellent cell adhesion inhibition effect, in which, P3 exhibited 7-fold enhancement in IC50 compared with cyclo(RGDfK). Drug-loaded cytotoxicity experiment and imaging experiment indicated that such dual-cyclic RGD peptides have good tumor targeting effects. This work provides a new strategy for the design of novel RGD peptides.

Mitoxantrone-Loaded PEGylated Gold Nanocomplexes for Cancer Therapy.

Gold nanoparticles (AuNPs) have been widely used as drug delivery carriers for cancer targeting and therapy. In this study, we developed mitoxantrone (MX)-loaded poly(ethylene glycol)-modified AuNPs complexes (AuNPs-PEG-MX) and evaluated its physicochemical properties compared to AuNPs, free MX, and MX-loaded AuNPs (AuNPs-MX). The results of surface plasmon resonance (SPR) measurement provided corresponded characteristics of free MX and AuNP groups, which determined by electrophoretic light scattering (ELS) method. The hydrodynamic size of AuNPs-PEG-MX was lower than that of AuNPs-MX. Furthermore, loading efficiency of AuNPs-PEG-MX was 1.9-fold increased than AuNPs-MX. In addition, AuNPs-PEG-MX showed similar cytotoxicity compared to AuNPs-MX group in HeLa cells with enhanced drug release. Conclusively, AuNPs-PEG-MX could be applied for in vivo cancer therapy via passive targeting based on the enhanced permeability and retention effect after intravenous injection.

RGD Conjugated Hyperbranched Cationic Amylopectin Nanoparticle as Hypoxia Inducible Factor-1α Targeting Carrier Promotes Neovascularization in Cerebral Infarction

Promoting the regeneration of new blood vessels is a crucial treatment in cerebral infarction and hypoxia-inducible factor 1-α (HIF-1α) plays a pivotal role in the regulation of neovascularization. Nevertheless, the degradation of HIF-1α and poor homing into ischemic sites greatly limit its clinical application. In this study, we encapsulated mutant HIF-1α in RGD modified hyperbranched cationic amylopectin derivative conjugated with 3-(dimethylamino)-1-propylamine (RGD-DMAPA-Amyp) nanoparticles. RGD-DMAPA-Amyp nanoparticles exhibited good blood compatibility and low cytotoxicity in hemolysis and MTT assay, and in vivo study showed low concentrations of RGD-DMAPA-Amyp and DMAPA-Amyp had no significant toxicity to zebrafish embryos. Further to investigate the targeting ability of RGD-DMAPA-Amyp in human umbilical vein endothelial cells and rats model of transient middle cerebral artery occlusion, the in vitro and in vivo results showed RGD-DMAPA-Amyp could specifically bind to vascular endothelial cells. Moreover, the RGD-DMAPA-Amyp/HIF-1α administration significantly reduced the incidence of cerebral ischemia in zebrafish. The pro-angiogenic effect of RGD-DMAPA-Amyp/HIF-1α was evaluated on zebra fish model of vascular loss, RGD-DMAPA-Amyp/HIF-1α were found could improve the growth of subintestinal vessels (SIVs). Our results imply that RGD-DMAPA-Amyp/HIF-1α might alleviate cerebral infarction in vivo via promoting neovascularization and could potentially be a very promising approach for cerebral infarction or ischemic diseases.

Nanostructured cubosomes in an in situ nasal gel system: an alternative approach for the controlled delivery of donepezil HCl to brain

The purpose of this research was to develop cubosomal mucoadhesive in situ nasal gel to enhance the donepezil HCl delivery to the brain. Glycerol mono-oleate (GMO) and surfactant poloxamer 407 were used to prepare cubosomes. The developed formulations were characterized for particle size (PS), poly dispersity index (PDI), zeta potential (ZP), entrapment efficiency (EE), transmission electron microscopy (TEM), in vitro drug release and in vivo bio-distribution study in blood and brain tissue. Central composite design was used for the optimization purpose and the selected formulation (containing GMO 2 g and poloxamer 1.5%) was prepared in presence of gellan gum and konjac gum as gelling agent and mucoadhesive agent respectively. The optimal cubosomal dispersion and optimal cubosomal mucoadhesive in situ nasal gel were subjected to in vivo bio-distribution studies in rat model. It showed significantly higher transnasal permeation and better distribution to the brain, when compared to the drug solution. Thus, the formulated cubosomal mucoadhesive in situ gel could be considered as a promising carrier for brain targeting of CNS acting drugs through the transnasal route.

Antibacterial Activity of Gold Nanoparticles Conjugated by Aminoglycosides Against A. baumannii Isolates from Burn Patients.

Today, resistance to multiple classes of antibiotics, and notably to the β-lactam and aminoglycosides in A. baumannii is becoming a great problem and it necessitates to make a new approach to combat with multidrug-resistant (MDR), extensive drug-resistance (XDR) or Pandrug-resistant (PDR) isolates. In this case, a new strategy and ways should be designed and introduced against such infections. Therefore the aim of the present study was the evaluation of antibacterial activity of nanoconjugate gentamicin and amikacin with gold against clinical isolates of A. baumannii that were collected from burn wound infection. There are some patents of gold nanoparticles that are conjugated with antibiotics (WO2017161296A1, US20090181101A1). Eighteen A. baumannii were collected from burn wound infections. For confirmation and detection of aminoglycoside-resistant genes, PCR was carried out. Gold nanoparticles and nanoconjugates were prepared according to the protocol. For the evaluation of the nanoconjugate, Dynamic light cattering, Transmission electron microscopy and FTIR Analysis were carried out. Then, the antibacterial activity of nanoconjugates was conducted by using micro broth dilution method. Prevalence of aminoglycoside-resistant genes was aacC1, aphA6, aadA1, aadB genes 55.5%, 22.2%, 38.8% and 22.2% respectively. Synthesis of bare nanoconjugates resulted in nanoparticle in a size of 10 nm. Amikacin bound to Gnps showed excellent antibacterial activity (94.5%) and just one isolate showed intermediate resistance. Also, gentamicin bound to Gnps had a good antimicrobial effect (50%) in contrast to gentamicin alone. Our study showed that a combination of amikacin and gentamicin with Gnps has a significant antibacterial efficiency against clinical isolates of A. baumannii. Gnps can be used as extraordinary molecular carriers for targeting, and delivery of the antibiotic molecules to the specific infection.

Design of 5-fluorouracil (5-FU) loaded, folate conjugated peptide linked nanoparticles, a potential new drug carrier for selective targeting of tumor cells.

In the present investigation folate peptide (FA-Pep) conjugated 5-fluorouracil (5-FU) loaded nanoparticles were synthesized and their tumor targeting potentiality was monitored by different in vitro and in vivo techniques. FA-Pep-1 and FA-Pep-2 were synthesized and radiolabeled with 99mTc(CO)3(H2O)3. 99mTc(CO)3-FA-Pep-1 exhibited promising tumor uptake in an in vivo model (nude mice bearing HeLa cell xenograft and Balb/c mice bearing B16F10 melanoma tumor) as compared to 99mTc(CO)3-FA-Pep-2. FA-Pep-1 was then conjugated with 5-FU-NPs (118 ± 4.3), as confirmed by the XPS study. These showed promising cytotoxic and apoptotic potential in B16F10 cell lines as compared to free 5-FU and unconjugated 5-FU-NPs. In vivo biodistribution and gamma-scintigraphy showed good accumulation of peptide conjugated NPs in the tumor region. Therapeutic efficacy studies in B16F10 tumor xenografts also exhibited substantial tumor growth inhibition. The above studies reveal that folate peptide conjugation may facilitate the tumor-targeting approach of 5-FU-NPs.

Folate-Modified Liposomes Loaded with Telmisartan Enhance Anti-Atherosclerotic Potency for Advanced Atherosclerosis in ApoE-/- Mice.

For the effective inhibition of atherosclerotic plaque rupture, there is an urgent need to develop a carrier which can specifically deliver the therapeutic agents to atherosclerotic lesions. Since the representative hallmark of plaques in advanced atherosclerosis is the large number of macrophages which highly upregulate folate receptor beta (FR-β), we herein investigated the potential of folate-modified liposomes (FA-P-LP) as the carrier for active targeting of atherosclerotic plaques. In vitro cellular uptake tests, FA-P-LP exhibited an enhanced uptake in activated RAW264.7 macrophages with high expression of FR-β, whereas this enhanced effect was dramatically diminished when the cells were pretreated with excess amount of free folate, indicating that FA-P-LP were mainly taken up by the receptor-mediated endocytosis. From the in vivo distribution assay, it was confirmly demonstrated that FA-P-LP significantly accumulated in atherosclerotic lesions and were co-localized with macrophages within plaques. Thereafter, we utilized the FA-P-LP to deliver an angiotensin receptor blocker (ARB), telmisartan (Tel), to macrophages in atherosclerotic plaques and evaluated their therapeutic effects on plaque destabilization. After 12 weeks treatment in ApoE-/- mice with established atherosclerosis, FA-P-LP/Tel exerted a marked improvement in key advanced plaque properties without affecting the plasma lipid level and blood pressure. These beneficial effects include the regression of atherosclerotic plaques possibly attributing to the enhanced cellular cholesterol efflux and reduced macrophage infiltration, an increase in the protective collagen layer overlying lesions resulting from suppression of collagenase activity and decrease in matrix 2/9 (MMP 2/9) expression, suppression of oxidative stress, and a reduction in plaque necrosis and calcification. Thus, administration of Tel in a targeted liposome could stabilize the advanced atherosclerotic lesions independent of lipid lowering and blood pressure decrease. In conclusion, FA-P-LP could effectively home to the atherosclerotic lesion through the active targeting mechanism after systemic administration, indicating their high potential as the carrier for atherosclerosis therapy. Together, the FA-P-LP/Tel would be considered as a promising nanotherapeutic approach to prevent plaque rupture, providing an alternative regimen for clinical treatment of advanced atherosclerosis.

Delivery of 5'-triphosphate RNA with endosomolytic nanoparticles potently activates RIG-I to improve cancer immunotherapy.

RNA agonists of the retinoic acid gene I (RIG-I) pathway have recently emerged as a promising class of cancer immunotherapeutics, but their efficacy is hindered by drug delivery barriers, including nuclease degradation, poor intracellular uptake, and minimal access to the cytosol where RIG-I is localized. Here, we explore the application of pH-responsive, endosomolytic polymer nanoparticles (NPs) to enhance the cytosolic delivery and immunostimulatory activity of synthetic 5' triphosphate, short, double-stranded RNA (3pRNA), a ligand for RIG-I. Delivery of 3pRNA with pH-responsive NPs with an active endosomal escape mechanism, but not control carriers lacking endosomolytic activity, significantly increased the activity of 3pRNA in dendritic cells, macrophages, and cancer cell lines. In a CT26 colon cancer model, activation of RIG-I via NP delivery of 3pRNA induced immunogenic cell death, triggered expression of type I interferon and pro-inflammatory cytokines, and increased CD8+ T cell infiltration into the tumor microenvironment. Consequently, intratumoral (IT) delivery of NPs loaded with 3pRNA inhibited CT26 tumor growth and enhanced the therapeutic efficacy of anti-PD-1 immune checkpoint blockade, resulting in a 30% complete response rate and generation of immunological memory that protected against tumor rechallenge. Collectively, these studies demonstrate that pH-responsive NPs can be harnessed to strongly enhance the immunostimulatory activity and therapeutic efficacy of 3pRNA and establish endosomal escape as a critical parameter in the design of carriers for immunotherapeutic targeting of the RIG-I pathway.

A dual fluorescent reverse targeting drug delivery system based on curcumin-loaded ovalbumin nanoparticles for allergy treatment

A reverse targeting drug delivery based on antigen-modified nanoparticles provided an innovative strategy for effectively alleviating or inhibiting immune response. In this study, a dual fluorescent reverse targeting drug delivery system based on curcumin-loaded ovalbumin nanoparticles is developed for allergy treatment. The self-crosslinked ovalbumin nanoparticles achieved the double function of reverse targeting and sustained delivery carriers to maximize the anti-allergy of curcumin. Using a murine model of ovalbumin-induced allergy, this drug delivery system suppressed antigen-specific IgG1 and IgE production, inhibited CD4+ T activity, and decreased the level of ovalbumin-sensitized memory B cells. The curcumin-loaded ovalbumin nanoparticles exert stronger and more effective treatment on the immunomodulatory role. Furthermore, fluorescence imaging in vivo can reveal the precise delivery process for the effective allergy immunotherapy. The dual fluorescent reverse targeting delivery system provided a significant potential for the visible treatment of allergy with the merged functions of targeting, vehicles and fluorescence.

Polymer Self-Assembled BMSCs with Cancer Tropism and Programmed Homing.

Targeted therapy can improve the accuracy of diagnosis and treatment in the field of cancer management. Cellular surface engineering can enhance cell functions via mounting functional molecules onto cellular membranes. A novel amphiphilic hyperbranched polymer (AHP) conjugated with oleic acid (OA) and tumor-targeted ligand folic acid (FA) is employed. The lipophilic chain can self-assemble and infuse with the cytomembrane of bone marrow mesenchymal stem cells (BMSCs) with the end of FA left on the outside for targeting. The polymer tailored BMSCs can enhance tumor tropism in gastric cancer. BMSCs are characterized by the low immunogenicity and tumor tropism, which makes them promising targeting carriers. Regarding the integrated advantages of these two vectors, it is demonstrated that the functional amphiphilic AHP-OA-FA enhances the tumor tropism of BMSCs. Flow cytometry, standard MTT assay, and wound-healing assay show that AHP-OA-FA has no influence on CD expression, proliferative capacity, and cell motility of BMSCs, respectively. Furthermore, in vitro transwell assay and ex vivo fluorescence image verify that AHP-OA-FA enhances tumor tropism of BMSCs compared to BMSCs and AHP-OA-Rhodamine B-BMSCs. Finally, histological analysis demonstrates that AHP-OA-FA causes no damage to major organs. The results of this study suggest that living BMSCs self-assembled with a polymer might be a promising vehicle for targeted delivery to cancer cells.

Glutaryl Polyamidoamine Dendrimer for Overcoming Cisplatin-Resistance of Breast Cancer Cells

Cisplatin has limited clinical applications due to drug resistance. PAMAM dendrimer was chosen as a vehicle to counteract cisplatin-resistance and its mechanism was assessed. Generation 5 Polyamidoamine dendrimer (G5) was modified by glutaric anhydride (GA) and then conjugated with cisplatin. The cisplatin release of G5-GA-cisplatin was evaluated at pH 5.5 and pH 7.4. The cytotoxicity of G5-GA-cisplatin and free cisplatin was compared in cisplatin-resistant breast cancer cell line MCF-7R. The intracellular platinum content of MCF-7R was determined using ICP-MS. The expression of Ctr1 and ATP7B of MCF-7R cells was also evaluated. An average of 75 amino groups present in the G5 PAMAM surface were converted into glutaric acid (G5-GA75) and platinum loading was 350±21 μg per 1 mg of G5-GA75. G5-Ac75-cisplatin complex exhibited controlled release of cisplatin at different pH over a period of 96 h. After 96 h incubation with G5-Ac75-cisplatin, cell viability was 27.47±2.53%, 12.18±0.65% and 11.62±0.84% using platinum concentration of 1 μg/ml, 3 μg/ml and 5 μg/ml, respectively. Meanwhile, 46.33±5.06% cells survived even in the high platinum concentration of 5 μg/ml after 96 h incubation with free cisplatin. G5-GA75 led to 3-6 times higher cisplatin accumulation than free cisplatin in MCF-7R cells, because MCF-7R cells exhibited lower Ctr1 expression and higher ATP7B expression than MCF-7 cells. The G5-GA75-cisplatin complex displayed greater anticancer activity than free cisplatin in the cisplatin-resistant breast cancer cell line MCF-7R. The low levels of Ctr1 and high levels of ATP7B in MCF-7R caused G5-GA75 to allow the accumulation of cisplatin, which in turn increased the cytotoxicity. Results indicated that glutaryl G5 PAMAM may be a potential carrier for cisplatin targeting in breast cancer.

Bifunctional reactive pentamethine cyanine dyes for biomedical applications

New unsymmetrical pentamethine cyanine dyes containing two non-equivalent reactive groups selected from carboxyl, amino and hydroxyl in different combinations were synthesized and their spectral properties investigated. Amino and hydroxy groups were used for binding the dyes to the anticancer drug, chlorambucil (CLB) via biodegradable amide or ester linker while the second reactive functionality could be utilized for attachment at mild conditions to a targeting carrier such as an antibody or peptide. These conjugates can thereby potentially be suitable for fluorescence-based monitoring of drug delivery. The CLB release profiles triggered by biodegradable linker were investigated in buffer solutions and cell medium using LC-MS and spectrofluorimetric methods.

Synthesis of multifunctional Fe3O4@PLGA-PEG nano-niosomes as a targeting carrier for treatment of cervical cancer

A new folic acid (FA)-conjugated poly (lactic-co-glycolicacid) (PLGA)-polyethylene glycol (PEG) nano-noisome was prepared. The noisome was employed as a drug delivery system to load curcumin (Cur) as a model drug and fluorescent probe for cervical cancer therapy and cell imaging. The Fe3O4@PLGA-PEG@FA noisomes were prepared through facile emulsion solvent evaporation and conjugation chemistry method, possessing the properties of high rapid magnetic separation and targeting character. X-ray photoelectron spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM) were adopted to characterize the chemical structure and properties of these niosomes. MTT assay revealed that the blank noisomes exhibited excellent biocompatibility. The in vitro drug loading and release behavior studier showed the as prepared nano-noisome presented ultrahigh performance as drug carrier. The confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) experiments demonstrated that Cur-loaded Fe3O4@PLGA-PEG@FA niosomes achieved significantly high targeting efficiency for cervical cancer. Additionally, the FA-targeted niosomes exhibited higher antitumor efficiency than free Cur. Cell morphology, the mitochondrial membrane potential and cell cycle changes indicated that Cur-loaded niosomes induced HeLa229 cells to apoptosis by destroying mitochondrion of cervical tumor cells, simultaneously changing nuclear morphology and blocking tumor cell proliferation. These results demonstrate that Fe3O4@PLGA-PEG@FA noisomes have promising applications as targeted drug delivery system for sustained drug release in cancer treatment.

Nanostructured gel for topical delivery of azelaic acid: Designing, characterization, and in-vitro evaluation

The study is designed to formulate, optimize and evaluate Azelaic acid loaded nano-structured lipid carrier (NLCs) with an aim to enhance its skin targeting, retention, and achieve sustained release with reduced drug related side effects. NLCs were formulated by melt emulsification and ultra-sonication technique and optimized employing 33 full factorial design taking lipid:drug ratio, surfactant concentration and sonication time as independent variables with particle size (PS) and entrapment efficiency (EE) as dependent variables. The optimized formulation (F23) exhibited spherical surfaced stable nano particles of 49.6 ± 1.24 nm size and 83.4 ± 2.14% EE. Formulation F23 was then incorporate to aloe-vera based carbopol gel and evaluated for its physiological properties, drug content, in-vitro release and skin distribution (fluorescent microscopy) analysis. The gel was found to be non-irritating, homogenous, with optimum moisture content, spreadability and occlusivity. In-vitro permeation studies showed NLC preparation to markedly enhance the dug's skin retention in comparison to drug suspended in gel and marketed preparation. The skin distribution studies employing rhodamine 6G further confirmed the permeation of NLCs to the deeper layers of skin. The experimental findings suggested that NLCs could serve as a promising carrier for site specific targeting with better skin retention abilities.

Radio-pharmaceuticals for cancer treatment: are they ready for prime time yet?

Radio-pharmaceuticals for cancer treatment: are they ready for prime time yet?

Abstract 2780: Engineering human fusion constructs for targeted delivery of granzyme B to CD33 and CEA antigens

Abstract Our laboratory has developed a unique platform for the delivery of the highly pro-apoptotic serine protease granzyme B (GrB). The construct contains enzymatically active GrB and therefore does not require release from the targeting carrier by a fragile linker in contrast to conventional antibody-drug conjugates (ADCs). We employed two scFvs targeting the CD33 antigen found on AML and the juxtamembrane epitope of CEA found on numerous solid tumors. These human scFvs (designated HU33 and CEA respectively) were fused to human GrB through an engineered IgG heavy-chain fragment (hinge to Fc and designated Fc) which contains a dimerization domain. The GrB-Fc-HU33 and GrB-Fc-CEA constructs were cloned into the pSECTag vector containing an upstream 5kDa purification tag with an enterokinase (EK) cleavage site for facile removal. The molecules were expressed in transiently-transfected HEK-293E suspension cells and grown at 37°C for 3 days in 5% CO2. The molecules were isolated from culture media and purified by IMAC followed by EK cleavage and SP chromatography to remove the free tag. The yields were 6-10 mg/L for both molecules. Specific binding of each molecule to the antigen target is undergoing Biacore and/or ELISA assessment. The cytotoxicity of the GrB-Fc-HU33 against HL-60 cells showed a specific cytotoxic effect with an IC50 of 120 nM. Tests of this agent against a panel of cells expressing various levels of CD33 are ongoing. The cytotoxic effects of the GrB-Fc-CEA were assessed against HT29, HT1080-CEA and A431 cells and demonstrated IC50 values of 80, 110 and 95 nM respectively. Based on IC50 values, these data demonstrate that the fusion construct targeting CD33 is efficiently internalized and effectively delivers active serine protease to the cytosol even at relatively low antigen expression levels. In addition, the juxtamembrane epitope of the CEA antibody also allows efficient internalization for delivery of GrB to the cytosol. Immunofluorescence and confocal studies to examine the time course of internalization and the pro-apoptotic events triggered by these agents are under examination and will be presented. Research conducted, in part, by the Clayton Foundation for Research. Citation Format: Lawrence H. Cheung, Khalid A. Mohamedali, Walter N. Hittelman, Michael G. Rosenblum. Engineering human fusion constructs for targeted delivery of granzyme B to CD33 and CEA antigens [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2780.

Carbon nanotubes with controlled length – preparation, characterization and their cytocompatibility effects

Abstract Multiwalled carbon nanotubes (MWCNTs) have attracted huge attention due to their multifunctionality. Their unique properties allows for covalent and noncovalent modifications. The most simple method for functionalization of carbon nanotubes is their decoration with the oxygen containing moieties which can be further simultaneously functionalized for design of new class carriers for targeting and imaging. Here, we present methodology for chopping nanotubes, characterization of MWCNTs, the effect of size on the biocompatibility in culture of L929 mouse fibroblasts using WST-1, LDH and apoptosis assays. The analysis provides the optimal carbon nanotubes length and concentration which can be used for functionalization in order to minimize the effect of the secondary agglomeration when interacting with cells.

Large set data mining reveals overexpressed GPCRs in prostate and breast cancer: potential for active targeting with engineered anti-cancer nanomedicines.

Over 800 G-protein-coupled receptors (GPCRs) are encoded by the human genome and many are overexpressed in tumors. GPCRs are triggered by ligand molecules outside the cell and activate internal signal transduction pathways driving cellular responses. The receptor signals are desensitized by receptor internalization and this mechanism can be exploited for the specific delivery of ligand-linked drug molecules directly into cells. Detailed expression analysis in cancer tissue can inform the design of GPCR-ligand decorated drug carriers for active tumor cell targeting. The active targeting process utilizes ligand receptor interactions leading to binding and in most cases internalization of the ligand-attached drug carrier resulting in effective targeting of cancer cells. In this report public microarray data from the Gene Expression Omnibus (GEO) repository was used to identify overexpressed GPCRs in prostate and breast cancer tissues. The analyzed data confirmed previously known cancer receptor associations and identified novel candidates for potential active targeting. Prioritization of the identified targeting receptors is also presented based on high expression levels and frequencies in cancer samples but low expression in healthy tissue. Finally, some selected examples were used in ligand docking studies to assess the feasibility for chemical conjugation to drug nanocarriers without interference of receptor binding and activation. The presented data demonstrate a large untapped potential to improve efficacy and safety of current and future anti-cancer compounds through active targeting of GPCRs on cancer cells.

Amphiphilic prodrug-decorated graphene oxide as a multi-functional drug delivery system for efficient cancer therapy

Graphene oxide (GO) has shown great potential in drug delivery. However, the aqueous stability, non-specific drug release and slow release rate are major problems of the GO-based drug delivery system. Herein, we for the first time integrate the dispersant, stabilizing agent and active targeting carrier into a novel drug delivery system based on GO/PP-SS-DOX nanohybrids. The redox-sensitive PP-SS-DOX prodrug was obtained by conjugating mPEG-PLGA (PP) with doxorubicin (DOX) via disulfide bond. PEG-FA provided active targeting property for the constructed drug delivery system, GO/PP-SS-DOX/PEG-FA. In this demonstrated system, PP-SS-DOX markedly increases the stability in physiological solutions of GO and guarantees the DOX release in the reductive environment (cancerous cells). And PEG-FA helps target to cancerous tissues and induces FR-mediated endocytosis. In vitro drug release exhibited the obvious reductive sensitivity and the cumulative release amount was up to 90%, while 40% in previous reports within 72 h. The in vitro cytotoxicity of targeting nanohybrids was significantly cytotoxic than that of non-targeting nanohybrids. In vivo results displayed that the as-prepared targeting nanohybrids showed efficacious antitumor effect while it had nearly no systemic adverse toxicity on B16 tumor-bearing mice. Therefore, the in vitro and in vivo results indicate that our constructed GO/PP-SS-DOX/PEG-FA drug delivery system is a promising carrier in cancer therapy.

Enhanced anti-proliferative efficacy of epothilone B loaded with Escherichia coli Nissle 1917 bacterial ghosts on the HeLa cells by mitochondrial pathway of apoptosis

Epothilones constitute a new class of microtubule-stabilizing anti-cancer agents with promising preclinical and clinical activity. However, its systemic application still causes some toxic side effects. To reduce these undesired effects, advanced drug delivery systems based on cell targeting carriers are needed currently. In this study, the high quality bacterial ghosts of the probiotic Escherichia coli Nissle 1917 (EcN) were prepared in a large scale and retained fully intact surface structures for specific attachment to mammalian cells. The EcN ghosts could be efficiently loaded with the low hydrophilic drug Epothilone B (Epo B) and the maximal load efficiency was approximately 2.5% (w/w). Cytotoxicity assays revealed that Epo B-ghosts exhibited enhanced anti-proliferative properties on the HeLa cells. The Epo B associated with EcN ghosts was more cytotoxic at least 10 times than the free Epo B at the same concentrations. Apoptosis assays showed that both Epo B-ghosts and free Epo B induced time course-dependent apoptosis and necrosis in HeLa cells, respectively. While the former induced more apoptosis and necrosis than the latter. Furthermore, the cytochrome C release and the activation of caspase-3 were more remarkable after treatment with the Epo B-ghosts compared to the free Epo B, which implied that Epo B-ghosts might more effectively induce the apoptosis mediated by mitochondrial pathway in HeLa cells. Therefore, the higher anti-proliferative effects of the Epo B-ghosts on the HeLa cells were mediated by mitochondrial pathway of apoptosis. The EcN ghosts may provide a useful drug delivery carrier for drug candidates in cancer therapy.