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1

Functionalized nanospheres for targeted delivery of paclitaxel.  

PubMed

Targeted delivery of anti-cancer agents to cancer cells is a mature line of investigation that has yet to realize its full potential. In this study we report on the development of a delivery platform with the future goal of merging two thus far parallel methods for selective elimination of cancer cells: targeted nanospheres and pretargeted radioimmunotherapy. Several clinical trials have shown the promise of pretargeted radioimmunotherapy, which leverages the specificity of antibodies for targeted cell populations and delivers a localized dose of a biotinylated radionuclide that is most often administered following binding of a biotinylated antibody and streptavidin (StA) to the target cells. The work presented here describes the development of biotinylated nanospheres based on an ABA-type copolymer comprised of a tyrosine-derived oligomer as the B-block and poly(ethylene glycol) (PEG) A-blocks. The biotinylated nanospheres encapsulate paclitaxel (PTX) to the same extent as unbiotinylated nanospheres. Efficacy of targeting was shown on CD44 positive cells in the SUM159 breast cancer cell line by incubating the cells sequentially with a biotinylated anti-CD44 antibody, StA and the biotinylated nanospheres encapsulating PTX. Targeted nanospheres achieved the half maximal inhibitory concentration of PTX on SUM159 cells at a 5-10 fold lower concentration than that of PTX applied in either non-targeted nanospheres or free drug approaches. Moreover, targeted nanospheres selectively eliminated CD44 positive SUM159 cells compared to free PTX and untargeted nanospheres. This new generation of nano-sized carrier offers a versatile platform that can be adopted for a wide variety of drug and target specific applications and has the potential to be combined with the clinically emerging method of pretargeted radioimmunotherapy. PMID:23792807

Bushman, Jared; Vaughan, Asa; Sheihet, Larisa; Zhang, Zheng; Costache, Marius; Kohn, Joachim

2013-06-20

2

HFT-T, a targeting nanoparticle, enhances specific delivery of paclitaxel to folate receptor-positive tumors.  

PubMed

Nonspecific distribution of chemotherapeutic drugs (such as paclitaxel) is a major factor contributing to side effects and poor clinical outcomes in the treatment of human head and neck cancer. To develop novel drug delivery systems with enhanced efficacy and minimized adverse effects, we synthesized a ternary conjugate heparin-folic acid-paclitaxel (HFT), loaded with additional paclitaxel (T). The resulting nanoparticle, HFT-T, is expected to retain the antitumor activity of paclitaxel and specifically target folate receptor (FR)-expressing tumors, thereby increasing the bioavailability and efficacy of paclitaxel. In vitro experiments found that HFT-T selectively recognizes FR-positive human head and neck cancer cell line KB-3-1, displaying higher cytotoxicity compared to the free form of paclitaxel. In a subcutaneous KB-3-1 xenograft model, HFT-T administration enhanced the specific delivery of paclitaxel into tumor tissues and remarkably improved antitumor efficacy of paclitaxel. The average tumor volume in the HFT-T treatment group was 92.9 +/- 78.2 mm(3) vs 1670.3 +/- 286.1 mm(3) in the mice treated with free paclitaxel. Furthermore, paclitaxel tumors showed a resurgence of growth after several weeks of treatment, but this was not observed with HFT-T. This indicates that HFT-T could be more effective in preventing tumors from developing drug resistance. No significant acute in vivo toxicity was observed. These results indicate that specific delivery of paclitaxel with a ternary structured nanoparticle (HFT-T) targeting FR-positive tumor is a promising strategy to enhance chemotherapy efficacy and minimize adverse effects. PMID:19761191

Wang, Xu; Li, Jun; Wang, Yiqing; Cho, Kwang Jae; Kim, Gloria; Gjyrezi, Ada; Koenig, Lydia; Giannakakou, Paraskevi; Shin, Hyung Ju C; Tighiouart, Mourad; Nie, Shuming; Chen, Zhuo Georgia; Shin, Dong M

2009-10-27

3

CD133-targeted paclitaxel delivery inhibits local tumor recurrence in a mouse model of breast cancer.  

PubMed

Expression of the membrane protein CD133 marks a subset of cancer cells with drug resistant phenotype and enhanced tumor initiating ability in xenotransplantation assays. Because drug resistance and tumor relapse are significant problems, approaches to eliminate these cells are urgently needed. As a step towards achieving this goal, we developed polymeric nanoparticles targeting CD133 by conjugating an anti-CD133 monoclonal antibody to nanoparticles formulated using poly(D,L lactide-co-glycolide) polymer. Nanoparticles were loaded with paclitaxel, a microtubule-stabilizing anticancer agent, as well as with 6-coumarin, a fluorescent probe. CD133-targeted nanoparticles (CD133NPs) were efficiently internalized by Caco-2 cells, which abundantly express CD133 (>9-fold higher uptake than non-targeted control nanoparticles). The effectiveness of CD133NPs in reducing tumor initiating cell (TIC) fraction was investigated using mammosphere formation and soft-agar colony formation assays. Free paclitaxel treatment was not effective in decreasing the TIC population relative to untreated control, whereas CD133NPs effectively decreased the number of mammospheres and colonies formed. In vivo studies in the MDA-MB-231 xenograft model showed that free paclitaxel was initially effective in inhibiting tumor growth but the tumors rebounded rapidly once the treatment was stopped. Tumor regrowth was significantly lower when paclitaxel was delivered through CD133NPs (tumor volume was 518.6±228 vs. 1370.9±295mm(3) for free paclitaxel at 63days; P<0.05). Our studies thus show that encapsulation of paclitaxel in CD133NPs results in a significant decrease in the TIC population and improved therapeutic efficacy compared to that with free paclitaxel treatment. These results indicate the potential of targeting anticancer therapeutics to CD133+ cells for reducing tumor recurrence. PMID:23871962

Swaminathan, Suresh Kumar; Roger, Emilie; Toti, Udaya; Niu, Lin; Ohlfest, John R; Panyam, Jayanth

2013-07-18

4

Dual targeting folate-conjugated hyaluronic acid polymeric micelles for paclitaxel delivery.  

PubMed

A series of novel self-assembled hyaluronic acid derivatives (HA-C(18)) grafted with hydrophobic octadecyl moiety and further dual targeting folic acid-conjugated HA-C(18) (FA-HA-C(18)) were synthesized. With the increase in the degree of substitution of octadecyl group from 12.7% to 19.3%, the critical micellar concentration of HA-C(18) copolymers decreased from 37.3 to 10.0 ?g/mL. Paclitaxel (PTX) was successfully encapsulated into the hydrophobic cores of the HA-C(18) and FA-HA-C(18) micelles, with encapsulation efficiency as high as 97.3%. The physicochemical properties of the polymeric micelles were measured by DLS, TEM and DSC. Moreover, in vitro release behavior of PTX was investigated by dialysis bag method and PTX was released from micelles in a near zero-order sustained manner. In vitro antitumor activity tests suggested PTX-loaded HA-C(18) and FA-HA-C(18) micelles exhibited significantly higher cytotoxic activity against MCF-7 and A549 cells compared to Taxol at a lower PTX concentration. The cellular uptake experiments were conducted by quantitative assay of PTX cellular accumulation and confocal laser scanning microscopy imaging of coumarin-6 labeled HA-C(18) and FA-HA-C(18) micelles in folate receptor overexpressing MCF-7 cells. Folate and CD44 receptor competitive inhibition studies performed by fluorescence microscopy imaging suggested intracellular delivery of HA-C(18) and FA-HA-C(18) micelles were efficiently taken up via CD44 receptor-mediated endocytosis. The folate receptor-mediated endocytosis further enhanced internalized amounts of FA-HA-C(18) micelles in MCF-7 cells, as compared with HA-C(18) micelles. The internalization pathways of PTX-loaded HA-C(18) and FA-HA-C(18) micelles might include clathrin-mediated endocytosis, caveolae-mediated endocytosis and macropinocytosis. Therefore, the present study suggested that HA-C(18) and FA-HA-C(18) copolymers as biodegradable, biocompatible and cell-specific targetable nanostructure carriers, are promising nanosystems for cellular and intracellular targeting delivery of hydrophobic anticancer drugs. PMID:21945183

Liu, Yanhua; Sun, Jin; Cao, Wen; Yang, Jianhong; Lian, He; Li, Xin; Sun, Yinghua; Wang, Yongjun; Wang, Siling; He, Zhonggui

2011-09-16

5

Targeted delivery of albumin bound paclitaxel in the treatment of advanced breast cancer  

PubMed Central

Taxanes are chemotherapeutic agents with a large spectrum of antitumor activity when used as monotherapy or in combination regimens. Paclitaxel and docetaxel have poor solubility and require a complex solvent system for their commercial formulation, Cremophor EL® (CrEL) and Tween 80® respectively. Both these biological surfactants have recently been implicated as contributing not only to the hypersensitivity reactions, but also to the degree of peripheral neurotoxicity and myelosuppression, and may antagonize the cytotoxicity. Nab-paclitaxel, or nanoparticle albumin-bound paclitaxel (ABI-007; Abraxane®), is a novel formulation of paclitaxel that does not employ the CrEL solvent system. Nab-paclitaxel demonstrates greater efficacy and a favorable safety profile compared with standard paclitaxel in patients with advanced disease (breast cancer, non-small cell lung cancer, melanoma, ovarian cancer). Clinical studies in breast cancer have shown that nab-paclitaxel is significantly more effective than standard paclitaxel in terms of overall objective response rate (ORR) and time to progression. Nab-paclitaxel in combination with gemcitabine, capecitabine or bevacizumab has been shown to be very active in patients with advanced breast cancer. An economic analysis showed that nab-paclitaxel would be an economically reasonable alternative to docetaxel or standard paclitaxel in metastatic breast cancer. Favorable tumor ORR and manageable toxicities have been reported for nab-paclitaxel as monotherapy or in combination treatment in advanced breast cancer.

Di Costanzo, Francesco; Gasperoni, Silvia; Rotella, Virginia; Di Costanzo, Federica

2009-01-01

6

Targeted delivery of insoluble cargo (paclitaxel) by PEGylated chitosan nanoparticles grafted with Arg-Gly-Asp (RGD).  

PubMed

Poor delivery of insoluble anticancer drugs has so far precluded their clinical application. In this study, we developed a tumor-targeting delivery system for insoluble drug (paclitaxel, PTX) by PEGylated O-carboxymethyl-chitosan (CMC) nanoparticles grafted with cyclic Arg-Gly-Asp (RGD) peptide. To improve the loading efficiency (LE), we combined O/W/O double emulsion method with temperature-programmed solidification technique and controlled PTX within the matrix network as in situ nanocrystallite form. Furthermore, these CMC nanoparticles were PEGylated, which could reduce recognition by the reticuloendothelial system (RES) and prolong the circulation time in blood. In addition, further graft of cyclic RGD peptide at the terminal of PEG chain endowed these nanoparticles with higher affinity to in vitro Lewis lung carcinoma (LLC) cells and in vivo tumor tissue. These outstanding properties enabled as-designed nanodevice to exhibit a greater tumor growth inhibition effect and much lower side effects over the commercial formulation Taxol. PMID:22559746

Lv, Pi-Ping; Ma, Yu-Feng; Yu, Rong; Yue, Hua; Ni, De-Zhi; Wei, Wei; Ma, Guang-Hui

2012-05-15

7

Enhanced antitumor effect of novel dual-targeted paclitaxel liposomes  

NASA Astrophysics Data System (ADS)

A novel dual-targeted peptide containing an alpha V integrins specific ligand and a neuropilin-1 specific motif was developed which showed an increased specific targeting affinity to tumors. Active dual-targeted liposomes were then produced with this peptide and exhibited greater binding activity than single-targeted liposomes in vitro. Paclitaxel entrapped in this formulation greatly increased the uptake of paclitaxel in the targeting cells and significantly suppressed the growth of HUVEC and A549 cells compared with general paclitaxel injections (Taxol) and single-targeted paclitaxel liposomes. The treatment of tumor xenograft models with dual-targeted paclitaxel liposomes also resulted in better tumor growth inhibition than any other treatment groups. Therefore, the dual-targeted paclitaxel liposomes prepared in the present study might be a more promising drug for cancer treatment. Furthermore, the dual-targeting approach may produce synergistic effects that can be applied in the development of new targeted drug delivery systems.

Meng, Shuyan; Su, Bo; Li, Wei; Ding, Yongmei; Tang, Liang; Zhou, Wei; Song, Yin; Li, Heyan; Zhou, Caicun

2010-10-01

8

Paclitaxel Nano-Delivery Systems: A Comprehensive Review  

PubMed Central

Paclitaxel is one of the most effective chemotherapeutic drugs ever developed and is active against a broad range of cancers, such as lung, ovarian, and breast cancers. Due to its low water solubility, paclitaxel is formulated in a mixture of Cremophor EL and dehydrated ethanol (50:50, v/v) a combination known as Taxol. However, Taxol has some severe side effects related to Cremophor EL and ethanol. Therefore, there is an urgent need for the development of alternative Taxol formulations. The encapsulation of paclitaxel in biodegradable and non-toxic nano-delivery systems can protect the drug from degradation during circulation and in-turn protect the body from toxic side effects of the drug thereby lowering its toxicity, increasing its circulation half-life, exhibiting improved pharmacokinetic profiles, and demonstrating better patient compliance. Also, nanoparticle-based delivery systems can take advantage of the enhanced permeability and retention (EPR) effect for passive tumor targeting, therefore, they are promising carriers to improve the therapeutic index and decrease the side effects of paclitaxel. To date, paclitaxel albumin-bound nanoparticles (Abraxane®) have been approved by the FDA for the treatment of metastatic breast cancer and non-small cell lung cancer (NSCLC). In addition, there are a number of novel paclitaxel nanoparticle formulations in clinical trials. In this comprehensive review, several types of developed paclitaxel nano-delivery systems will be covered and discussed, such as polymeric nanoparticles, lipid-based formulations, polymer conjugates, inorganic nanoparticles, carbon nanotubes, nanocrystals, and cyclodextrin nanoparticles.

Ma, Ping; Mumper, Russell J.

2013-01-01

9

Paclitaxel loaded fibrinogen coated CdTe/ZnTe core shell nanoparticles for targeted imaging and drug delivery to breast cancer cells.  

PubMed

The study aims at the targeted imaging using CdTe/ZnTe core shell QDs and delivery of paclitaxel (PTX) loaded fibrinogen coated yellow-QDs (PTX-fib-yellow-QDs) towards breast cancer cells via the alpha5Beta1-integrins. We developed fibrinogen coated different sized CdTe/ZnTe core shell quantum dots of 2-10 nm size, which have been prepared by one-pot aqueous-phase approach. The fib-coated-QDs (fib-coated-QDs) and PTX-fib-yellow-QDs were prepared by two-step coacervation technique using CaCl2 as cross-linker. Particle size of fib-coated-QDs was in between 60-220 nm while PTX-fib-yellow-QDs showed 180 +/- 40 nm. The MTT assay confirmed cytocompatibility of fib-coated-QDs on L929 and MCF-7 than bare QDs, whereas significant toxicity toward MCF-7 by PTX-fib-yellow-QDs was observed. The hemocompatible fib-coated-QDs showed enhanced localization and retention toward alpha5beta1-integrins +ve MCF-7 compared to alpha5beta1-integrins -ve L929 cells. The specific binding of fib-coated-yellow-QDs was further confirmed with alpha5beta1-integrins +ve HeLa and alpha5/beta1-integrins -ve HT29 cells. Cellular uptake studies revealed localization of PTX-fib-coated-yellow-QDs inside MCF-7 cells compared to the normal L929 cells. These results indicated that fib-coated-QDs could be used for targeted imaging and as a suitable "nanocarrier" aiming breast cancer cells. PMID:24015495

Rejinold, N Sanoj; Baby, Thejus; Nair, Shantikumar V; Jayakumar, R

2013-10-01

10

Folate-mediated targeted and intracellular delivery of paclitaxel using a novel deoxycholic acid-O-carboxymethylated chitosan-folic acid micelles  

PubMed Central

Background A critical disadvantage for successful chemotherapy with paclitaxel (PTX) is its nontargeting nature to cancer cells. Folic acid has been employed as a targeting ligand of various anticancer agents to increase their cellular uptake within target cells since the folate receptor is overexpressed on the surface of such tumor cells. In this study, a novel biodegradable deoxycholic acid-O-carboxymethylated chitosan–folic acid conjugate (DOMC-FA) was used to form micelles for encapsulating the anticancer drug PTX. Methods and results The drug-loading efficiency, encapsulation efficiency, in vitro drug release and physicochemical properties of PTX-loaded micelles were investigated in detail. In vitro cell culture studies were carried out in MCF-7 cells, a human breast carcinoma cell line, with folate receptor overexpressed on its surface. An increased level of uptake of folate-conjugated micelles compared to plain micelles in MCF-7 cells was observed, and the enhanced uptake of folate-micelles mainly on account of the effective process of folate receptor-mediated endocytosis. The MTT assay, morphological changes, and apoptosis test implied that the folate-conjugated micelles enhanced the cell death by folate-mediated active internalization, and the cytotoxicity of the FA-micellar PTX (DOMC-FA/PTX) to cancer cells was much higher than micelles without folate (DOMC/PTX) or the commercially available injectable preparation of PTX (Taxol). Conclusion Results indicate that the PTX-loaded DOMC-FA micelle is a successful anticancertargeted drug-delivery system for effective cancer chemotherapy.

Wang, Feihu; Chen, Yuxuan; Zhang, Dianrui; Zhang, Qiang; Zheng, Dandan; Hao, Leilei; Liu, Yue; Duan, Cunxian; Jia, Lejiao; Liu, Guangpu

2012-01-01

11

Doxorubicin and paclitaxel loaded microbubbles for ultrasound triggered drug delivery  

PubMed Central

A polymer ultrasound contrast agent (UCA) developed in our lab has been shown to greatly reduce in size when exposed to ultrasound, resulting in nanoparticles less than 400 nm in diameter capable of escaping the leaky vasculature of a tumor to provide a sustained release of drug. Previous studies with the hydrophilic drug doxorubicin (DOX) demonstrated enhanced drug delivery to tumors when triggered with ultrasound. However the therapeutic potential has been limited due to the relatively low payload of DOX. This study compares the effects of loading the hydrophobic drug paclitaxel (PTX) on the agent’s acoustic properties, drug payload, tumoricidal activity, and the ability to deliver drugs through 400 nm pores. A maximum payload of 129.46 ± 1.80 ?g PTX/mg UCA (encapsulation efficiency 71.92 ± 0.99 %) was achieved, 20 times greater than the maximum payload of DOX (6.2 ?g/mg), while maintaining the acoustic properties. In vitro, the tumoricidal activity of paclitaxel loaded UCA exposed to ultrasound was significantly greater than controls not exposed to ultrasound (p<0.0016). This study has shown that PTX loaded UCA triggered with focused ultrasound have the potential to provide a targeted and sustained delivery of drug to tumors.

Cochran, Michael C.; Eisenbrey, John; Ouma, Richard O.; Soulen, Michael; Wheatley, Margaret A.

2011-01-01

12

The anticancer efficacy of paclitaxel liposomes modified with mitochondrial targeting conjugate in resistant lung cancer.  

PubMed

Lung cancer is the leading cause of cancer-related death in humans and the multidrug resistance (MDR) is the major obstacle to successful chemotherapy of lung cancer. In this study, a d-?-tocopheryl polyethylene glycol 1000 succinate-triphenylphosphine conjugate (TPGS1000-TPP) was synthesized as the mitochondrial targeting molecule, and was incorporated onto the surface of paclitaxel liposomes to treat the drug-resistant lung cancer. Evaluations were performed on the human lung cancer A549 cells, the drug-resistant lung cancer A549/cDDP cells, and the drug-resistant lung cancer A549/cDDP cells xenografted nude mice. The yield of TPGS1000-TPP conjugate synthesized was about 50% and the particle size of targeting paclitaxel liposomes developed was approximately 80 nm. In comparison with taxol and regular paclitaxel liposomes, the targeting paclitaxel liposomes exhibited the strongest anticancer efficacy in vitro and in the drug-resistant A549/cDDP xenografted tumor model. The targeting paclitaxel liposomes could significantly enhance the cellular uptake, be selectively accumulated into the mitochondria, and cause the release of cytochrome C. This targeting delivery of drug initiated a cascade of caspase 9 and 3 reactions, activated the pro-apoptotic Bax and Bid proteins and suppressed the anti-apoptotic Bcl-2 protein, thereby enhancing the apoptosis by acting on the mitochondrial signaling pathways. In conclusion, the targeting paclitaxel liposomes have the potential to treat drug-resistant lung cancer. PMID:23422592

Zhou, Jia; Zhao, Wei-Yu; Ma, Xu; Ju, Rui-Jun; Li, Xiu-Ying; Li, Nan; Sun, Meng-Ge; Shi, Ji-Feng; Zhang, Cheng-Xiang; Lu, Wan-Liang

2013-02-16

13

Efficient simultaneous tumor targeting delivery of all-trans retinoid acid and Paclitaxel based on hyaluronic acid-based multifunctional nanocarrier.  

PubMed

An amphiphilic hyaluronic acid (HA)-g-all-trans retinoid acid (HRA) conjugate was successfully developed as a tumor-targeting nanocarrier for potentially synergistic combination chemotherapy of all-trans retinoid acid (ATRA) and paclitaxel (PTX). The HRA conjugate was synthesized by an imine reaction between HA-COOH and ATRA-NH2. PTX-loaded HRA nanoparticles possessed a high loading capacity, nanoscale particle sizes, and good biocompatible characteristics. Cell viability assays indicated that PTX-loaded HRA nanoparticles exhibited concentration- and time-dependent cytotoxicity. Moreover, they displayed obvious superiority in inducing the apoptosis of tumor cells. Cellular uptake analysis suggested that HRA nanoparticles could be efficiently taken up by cells via endocytic pathway and transport into the nucleus, contributing to HA receptor-mediated endocytosis and ATRA-induced nuclear translocation, respectively. Moreover, in vivo imaging analysis indicated that the accumulation of DiR-loaded HRA nanoparticles in tumor was increased obviously after intravenous administration as compared to free DiR solution, which confirmed that the HRA nanoparticles could assist the drugs targeting to the tumor. Furthermore, PTX-loaded HRA nanoparticles exhibited greater tumor growth inhibition effect in vivo with reducing the toxicity. Therefore, HRA nanoparticles can be considered as a promising targeted codelivery system for combination cancer chemotherapy. PMID:23320642

Yao, Jing; Zhang, Li; Zhou, Jianping; Liu, Hongpan; Zhang, Qiang

2013-01-31

14

Stepwise Orthogonal Click Chemistry toward Fabrication of Paclitaxel/Galactose Functionalized Fluorescent Nanoparticles for HepG2 Cell Targeting and Delivery.  

PubMed

In this report, we used stepwise orthogonal click chemistry (SOCC) involving strain-promoted azide-alkyne cycloaddition (SPAAC) and microwave-assisted Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) to assemble an anticancer drug (paclitaxel, PTX) and a targeting ligand (trivalent galactoside, TGal) on a fluorescent silicon oxide nanoparticle (NP) by using dialkyne linker 8 as a bridge. The fluorescent NH2@Cy3SiO2NP was fabricated using a competition method to incorporate Cy3 without loss of the original surface amine density on the NPs. The concept of SOCC was first investigated in a solution-phase model study that showed quantitative reaction yield. In the fabrication of TGal-PTX@Cy3SiO2NP, the expensive compound azido-functionalized PTX 12 used in SPAAC can be easily recovered due to the absence of other reagents in the reaction mixture. High loading of the sugar ligand on the NP surface serves a targeting function and also overcomes the low water solubility of PTX. Confocal fluorescence microscopy and cytotoxicity assay showed that TGal-PTX@Cy3SiO2NP was taken up by HepG2 cells and was affected by the microtubule skeleton in these cells and inhibited the proliferation of these cells in a dose-dependent manner. The presence of a fluorescent probe, a targeting ligand, and an anticancer drug on the multifunctional TGal-PTX@Cy3SiO2NP allows for real-time imaging, specific cancer-cell targeting, and the cell-killing effect which is better than free PTX. PMID:23987828

Lai, Chian-Hui; Chang, Tsung-Che; Chuang, Yung-Jen; Tzou, Der-Lii; Lin, Chun-Cheng

2013-09-19

15

Designing Paclitaxel Drug Delivery Systems Aimed at Improved Patient Outcomes: Current Status and Challenges  

PubMed Central

Paclitaxel is one of the most widely used and effective antineoplastic agents derived from natural sources. It has a wide spectrum of antitumor activity, particularly against ovarian cancer, breast cancer, nonsmall cell lung cancer, head and neck tumors, Kaposi's sarcoma, and urologic malignancies. It is a highly lipophilic compound with a log P value of 3.96 and very poor aqueous solubility of less than 0.01?mg/mL. In addition, the compound lacks functional groups that are ionizable which could potentially lead to an increase in its solubility with the alteration in pH. Therefore, the delivery of paclitaxel is associated with substantial challenges. Until the introduction of Abraxane, only commercial formulation was solution of paclitaxel in cremophor, which caused severe side effects. However, in recent years, a number of approaches have been reported to solubilize paclitaxel using cosolvents and inclusion complexes. In addition, innovative approaches have been reported for passive targeting of tumors using nanoparticles, nanosuspensions, liposomes, emulsions, micelles, implants, pastes and gels. All approaches for delivery of improved therapeutic outcome have been discussed in this paper.

Surapaneni, Madhu S.; Das, Sudip K.; Das, Nandita G.

2012-01-01

16

Antitumour activity of ANG1005, a conjugate between paclitaxel and the new brain delivery vector Angiopep-2  

PubMed Central

Background and purpose: Paclitaxel is highly efficacious in the treatment of breast, head and neck, non-small cell lung cancers and ovarian carcinoma. For malignant gliomas, paclitaxel is prevented from reaching its target by the presence of the efflux pump P-glycoprotein (P-gp) at the blood–brain barrier. We investigated the utilization of a new drug delivery system to increase brain delivery of paclitaxel. Experimental approach: Paclitaxel molecules were conjugated to a brain peptide vector, Angiopep-2, to provide a paclitaxel–Angiopep-2 conjugate named ANG1005. We determined the brain uptake capacity, intracellular effects and antitumour properties of ANG1005 in vitro against human tumour cell lines and in vivo in human xenografts. We then determined ANG1005 activity on brain tumours with intracerebral human tumour models in nude mice. Key results: We show by in situ brain perfusion that ANG1005 enters the brain to a greater extent than paclitaxel and bypasses the P-gp. ANG1005 has an antineoplastic potency similar to that of paclitaxel against human cancer cell lines. We also demonstrate that ANG1005 caused a more potent inhibition of human tumour xenografts than paclitaxel. Finally, ANG1005 administration led to a significant increase in the survival of mice with intracerebral implantation of U87 MG glioblastoma cells or NCI-H460 lung carcinoma cells. Conclusions and implications: These results demonstrate the antitumour potential of a new drug, ANG1005, and establish that conjugation of anticancer agents with the Angiopep-2 peptide vector could increase their efficacy in the treatment of brain cancer.

Regina, A; Demeule, M; Che, C; Lavallee, I; Poirier, J; Gabathuler, R; Beliveau, R; Castaigne, J-P

2008-01-01

17

Paclitaxel nanosuspensions for targeted chemotherapy - nanosuspension preparation, characterization, and use.  

PubMed

Abstract Objective: The purpose of this work was to prepare a stable paclitaxel nanosuspension and test it for potential use as a targeted chemotherapeutic. Different particle coatings were employed to assess their impact on cellular uptake in vitro. In vivo work was then performed to demonstrate efficacy in tumor-bearing mouse models. Materials and method: Paclitaxel nanosuspensions were prepared using a homogenization process and coated with excipients. Surface charge was measured by zeta potential, potency by high-performance liquid chromatography, and solubility using an in-line UV probe. Cellular uptake studies were performed via flow cytometry. In vivo experiments were performed to determine residence time, maximum tolerated dose, and the efficacy of paclitaxel nanosuspensions (Paclitaxel-NS). Results: A stable paclitaxel nanosuspension was prepared and coated with various excipients. Studies in mice showed that the nanosuspension was well-tolerated and at least as effective as the IV Taxol control in prolonging mouse survival in a head and neck cancer model as well as an ovarian cancer model with a lower overall drug dose than the traditional IV administration route. Conclusions: The paclitaxel nanosuspension is suitable for cellular uptake. The nanosuspension was effective in prolonging life in two separate xenograft orthotopic murine cancer models through two separate routes of administration. PMID:23617261

Lee, Sarah E; Bairstow, Shawn F; Werling, Jane O; Chaubal, Mahesh V; Lin, Lawrence; Murphy, Mary Ann; Diorio, James P; Gass, Jerome; Rabinow, Barrett; Wang, Xiaoen; Zhang, Yong; Yang, Zhijian; Hoffman, Robert M

2013-04-25

18

Covalent linkage of nanodiamond-paclitaxel for drug delivery and cancer therapy  

NASA Astrophysics Data System (ADS)

A nanoparticle-conjugated cancer drug provides a novel strategy for cancer therapy. In this study, we manipulated nanodiamond (ND), a carbon nanomaterial, to covalently link paclitaxel for cancer drug delivery and therapy. Paclitaxel was bound to the surface of 3-5 nm sized ND through a succession of chemical modifications. The ND-paclitaxel conjugation was measured by atomic force microscope and nuclear magnetic resonance spectroscopy, and confirmed with infrared spectroscopy by the detection of deuterated paclitaxel. Treatment with 0.1-50 µg ml - 1 ND-paclitaxel for 48 h significantly reduced the cell viability in the A549 human lung carcinoma cells. ND-paclitaxel induced both mitotic arrest and apoptosis in A549 cells. However, ND alone or denatured ND-paclitaxel (after treatment with strong alkaline solution, 1 M NaOH) did not induce the damage effects on A549 cells. ND-paclitaxel was taken into lung cancer cells in a concentration-dependent manner using flow cytometer analysis. The ND-paclitaxel particles were located in the microtubules and cytoplasm of A549 cells observed by confocal microscopy. Furthermore, ND-paclitaxel markedly blocked the tumor growth and formation of lung cancer cells in xenograft SCID mice. Together, we provide a functional covalent conjugation of ND-paclitaxel, which can be delivered into lung carcinoma cells and preserves the anticancer activities on the induction of mitotic blockage, apoptosis and anti-tumorigenesis.

Liu, Kuang-Kai; Zheng, Wen-Wei; Wang, Chi-Ching; Chiu, Yu-Chung; Cheng, Chia-Liang; Lo, Yu-Shiu; Chen, Chinpiao; Chao, Jui-I.

2010-08-01

19

Combined Delivery of Paclitaxel and Tanespimycin via Micellar Nanocarriers: Pharmacokinetics, Efficacy and Metabolomic Analysis  

PubMed Central

Background Despite the promising anticancer efficacy observed in preclinical studies, paclitaxel and tanespimycin (17-AAG) combination therapy has yielded meager responses in a phase I clinical trial. One serious problem associated with paclitaxel/17-AAG combination therapy is the employment of large quantities of toxic organic surfactants and solvents for drug solubilization. The goal of this study was to evaluate a micellar formulation for the concurrent delivery of paclitaxel and 17-AAG in vivo. Methodology/Principal Findings Paclitaxel/17-AAG-loaded micelles were assessed in mice bearing human ovarian tumor xenografts. Compared with the free drugs at equivalent doses, intravenous administration of paclitaxel/17-AAG-loaded micelles led to 3.5- and 1.7-fold increase in the tumor concentrations of paclitaxel and 17-AAG, respectively, without significant altering drug levels in normal organs. The enhanced tumor accumulation of the micellar drugs was further confirmed by the whole-body near infrared imaging using indocyanine green-labeled micelles. Subsequently, the anticancer efficacy of paclitaxel/17-AAG-loaded micelles was examined in comparison with the free drugs (weekly 20 mg/kg paclitaxel, twice-weekly 37.5 mg/kg 17-AAG). We found that paclitaxel/17-AAG-loaded micelles caused near-complete arrest of tumor growth, whereas the free drug-treated tumors experienced rapid growth shortly after the 3-week treatment period ended. Furthermore, comparative metabolomic profiling by proton nuclear magnetic resonance revealed significant decrease in glucose, lactate and alanine with simultaneous increase in glutamine, glutamate, aspartate, choline, creatine and acetate levels in the tumors of mice treated with paclitaxel/17-AAG-loaded micelles. Conclusions/Significance We have demonstrated in the current wok a safe and efficacious nano-sized formulation for the combined delivery of paclitaxel and 17-AAG, and uncovered unique metabolomic signatures in the tumor that correlate with the favorable therapeutic response to paclitaxel/17-AAG combination therapy.

Wang, Yingzhe; Teng, Quincy; Tan, Chalet

2013-01-01

20

Targeting of albumin-embedded paclitaxel nanoparticles to tumors  

Microsoft Academic Search

We have used tumor-homing peptides to target abraxane, a clinically approved paclitaxel-albumin nanoparticle, to tumors in mice. The targeting was accomplished with two peptides, CREKA and LyP-1 (CGNKRTRGC). Fluorescein (FAM)-labeled CREKA-abraxane, when injected intravenously into mice bearing MDA-MB-435 human cancer xenografts, accumulated in tumor blood vessels, forming aggregates that contained red blood cells and fibrin. FAM-LyP-1-abraxane co-localized with extravascular islands

Priya Prakash Karmali; Venkata Ramana Kotamraju; Mark Kastantin; Matthew Black; Dimitris Missirlis; Matthew Tirrell; Erkki Ruoslahti

2009-01-01

21

Targeted nanoparticles that deliver a sustained, specific release of paclitaxel to irradiated tumors  

PubMed Central

To capitalize on the response of tumor cells to ionizing radiation, we developed a controlled-release nanoparticle drug delivery system using a targeting peptide that recognizes a radiation-induced cell surface receptor. Phage display biopanning identified Gly-Ile-Arg-Leu-Arg-Gly (GIRLRG) as a peptide that selectively recognizes tumors responding to ionizing radiation. Membrane protein extracts of irradiated glioma cells identified glucose-regulated protein GRP78 as the receptor target for GIRLRG. Antibodies to GRP78 blocked the binding of GIRLRG in vitro and in vivo. Conjugation of GIRLRG to a sustained-release nanoparticle drug delivery system yielded increased paclitaxel concentration and apoptosis in irradiated breast carcinomas for up to three weeks. Compared to controls, a single administration of the GIRLRG-targeted nanoparticle drug delivery system to irradiated tumors delayed the in vivo tumor tripling time by 55 days (P=0.0001) in MDA-MB-231, and 12 days in GL261 (P<0.005). This targeting agent combines a novel recombinant peptide with a paclitaxel encapsulating nanoparticle that specifically targets irradiated tumors, increasing apoptosis and tumor growth delay in a manner superior to known chemotherapy approaches.

Passarella, Ralph J.; Spratt, Daniel E.; van der Ende, Alice E.; Phillips, John G.; Wu, Hongmei; Sathiyakumar, Vasanth; Zhou, Li; Hallahan, Dennis E.; Harth, Eva; Diaz, Roberto

2010-01-01

22

Inhibition of neointimal hyperplasia in vascular grafts by sustained perivascular delivery of paclitaxel  

Microsoft Academic Search

Inhibition of neointimal hyperplasia in vascular grafts by sustained perivascular delivery of paclitaxel.BackgroundNeointimal hyperplasia occurs commonly at the anastomoses of arteriovenous grafts for chronic hemodialysis, causing stenosis and occlusion. Antiproliferative drugs may be effective in inhibiting hyperplasia, but local drug delivery would be required to minimize systemic side effects. We examined the feasibility of local drug delivery to inhibit neointimal

TAKAHISA MASAKI; RAMESH RATHI; GAYLEN ZENTNER; John K. Leypoldt; Syed F. Mohammad; Gregory L. Burns; LI LI; SERGEY ZHUPLATOV; THANIT CHIRANANTHAVAT; SEUNG-JUNG KIM; STEVEN KERN; JOHN HOLMAN; SUNG WAN KIM; Alfred K. Cheung

2004-01-01

23

Self-aggregated pegylated poly (trimethylene carbonate) nanoparticles decorated with c(RGDyK) peptide for targeted paclitaxel delivery to integrin-rich tumors  

Microsoft Academic Search

Cyclic RGD peptide-decorated polymeric micellar-like nanoparticles (MNP) based on PEGylated poly (trimethylene carbonate) (PEG-PTMC) were prepared for active targeting to integrin-rich cancer cells. An amphiphilic diblock copolymer, ?-carboxyl poly (ethylene glycol)-poly (trimethylene carbonate) (HOOC-PEG-PTMC)?was synthesized by ring-opening polymerization. The c(RGDyK) ligand, a cyclic RGD peptide that can bind to the integrin proteins predominantly expressed on the surface of tumor cells

Xinyi Jiang; Xianyi Sha; Hongliang Xin; Liangcen Chen; Xihui Gao; Xiao Wang; Kitki Law; Jijin Gu; Yanzuo Chen; Ye Jiang; Xiaoqing Ren; Qiuyue Ren; Xiaoling Fang

2011-01-01

24

Localized delivery of paclitaxel using elastic liposomes: formulation development and evaluation.  

PubMed

In the present study an elastic liposomes-based paclitaxel formulation was developed with the objective to remove Cremophor EL. Cremophor EL is currently used for solubilizing paclitaxel in the marketed formulation and is known to produce toxic effects. Elastic liposomal paclitaxel formulation was extensively characterized in vitro, ex-vivo, and in vivo. The results obtained were compared against the marketed paclitaxel formulation. The maximum amount of paclitaxel loaded in the elastic liposomal formulation was found to be 6.0 mg/ml, which is similar to the commercial strength of marketed paclitaxel formulation. In vitro skin permeation and deposition studies showed 10.8-fold enhanced steady state transdermal flux and 15.0-fold enhanced drug deposition in comparison to drug solution. These results further confirmed with the vesicle-skin interaction study using FTIR technique. Results of the hemolytic toxicity assay indicate that elastic liposomal formulation induced only 11.2 ± 0.2% hemolysis in comparison to the commercial formulation which showed 38 ± 3.0%. Further, results of the Draize test showed no skin irritation of paclitaxel elastic liposomal formulation. Findings of the study demonstrate that elastic liposomes as a carrier is an attractive approach for localized delivery of paclitaxel. PMID:21428706

Utreja, Puneet; Jain, Subheet; Tiwary, A K

2011-03-23

25

Tumor targeting effects of a novel modified paclitaxel-loaded discoidal mimic high density lipoproteins.  

PubMed

Abstract Objective: Monocholesterylsuccinate (CHS)-modified paclitaxel-loaded discoidal reconstituted high density lipoproteins (cP-d-rHDL) as novel biomimetic nanocarriers that were developed for tumor targeting delivery to avoid unexpected drug leakage from discoidal reconstituted high density lipoproteins (d-rHDL) during remodeling process associated with lecithin-cholesterol acyltransferase (LCAT). Methods: Their in vitro characterizations and biomimetic properties, simultaneously tumor distribution and pharmacodynamics in tumor bearing mice were elaborately investigated. Results. In vitro characterization results showed that cP-d-rHDL had nano-size diameter, high negative zeta potential and high entrapment efficiency (EE). Furthermore, morphology study indicated that cP-d-rHDL did not remodel in the presence of LCAT, compared with that of paclitaxel-loaded d-rHDL (P-d-rHDL, not modified). And cellular uptake, together with cytotoxicity toward tumor cells of cP-d-rHDL was not affected after interaction with LCAT. Tumor distribution and pharmacodynamics tests revealed that cP-d-rHDL possessed specific targeting property and anti-tumor efficacy. Conclusion: cP-d-rHDL served to restrain remodeling process and drug leakage, at the same time reinforce the targeting effect, and could act as a potential drug delivery system for cancer therapy. PMID:24079327

Wang, Ji; Jia, Junting; Liu, Jianping; He, Hongliang; Zhang, Wenli; Li, Zhenghua

2013-09-30

26

Co-delivery of TRAIL gene enhances the anti-glioblastoma effect of paclitaxel in vitro and in vivo.  

PubMed

Co-delivery of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and paclitaxel (PTX) is an attractive strategy to enhance their anti-tumor efficacy. As the most aggressive brain tumor, glioblastoma is sensitive to TRAIL and PTX. However, their therapeutic efficacy for intracranial glioblastoma is significantly impaired by blood-brain barrier (BBB) and blood-tumor barrier (BTB). Previously, we have prepared c(RGDyK)-poly(ethylene glycol)-polyethyleneimine (RGD-PEG-PEI) as a non-viral gene carrier for glioblastoma targeted therapy by employing a cyclic RGD peptide (c(RGDyK), cyclic arginine-glycine-aspartic acid-d-tyrosine-lysine), which binds to integrin ?(v)?(3) over-expressed neovasculature and U87 glioblastoma cells with high affinities. In the present work, it was found that low concentration of paclitaxel (10nM) significantly enhanced the gene transfection of RGD-PEG-PEI/pDNA nanoparticle, which, in turn, dramatically elevated the anti-glioblastoma effect of paclitaxel in vitro. The gene transfection was also elevated in vivo. Co-delivery of brain-targeted CDX-PEG-PLA-PTX micelle dramatically enhanced gene transfection efficiency in the intracranial brain tumor. Due to the change of BBB integrity and the formation of BTB, we subsequently investigated the anti-glioblastoma effects of RGD-PEG-PEI/pORF-hTRAIL nanoparticle combined with CDX-PEG-PLA-PTX micelle (paclitaxel loaded CDX-poly(ethylene glycol)-block-poly(lactic acid) micelle). While at the same dosages, the median survival of the intracranial glioblastoma-bearing model mice treated with co-delivery (33.5 days) is significantly longer than those of solely treated mice with CDX-PEG-PLA-PTX (25.5 days), RGD-PEG-PEI/pORF-hTRAIL (24.5 days) or physiological saline (21.5 days). Herein, we verify the high potency of co-delivery of TRAIL gene and paclitaxel in the intervention of intracranial glioblastoma by employing tumor-targeted gene carrier RGD-PEG-PEI and brain-targeted micelle CDX-PEG-PLA, respectively. PMID:22410115

Zhan, Changyou; Wei, Xiaoli; Qian, Jun; Feng, Linglin; Zhu, Jianhua; Lu, Weiyue

2012-03-03

27

Oral paclitaxel and concurrent cyclosporin A: targeting clinically relevant systemic exposure to paclitaxel.  

PubMed

Oral paclitaxel is not inherently bioavailable because of the overexpression of P-glycoprotein by intestinal cells and the significant first-pass extraction by cytochrome P450-dependent processes. This study sought to simulate the toxicological and pharmacological profile of a clinically relevant schedule of paclitaxel administered on clinically relevant i.v. dosing schedules in patients with advanced solid malignancies using oral paclitaxel administered with cyclosporin A, an inhibitor of both P-glycoprotein and P450 CYP3A. Nine patients were treated with a single course of oral paclitaxel in its parenteral formulation at a paclitaxel dose level of 180, 360, or 540 mg. Cyclosporin A was administered at a dose of 5 mg/kg p.o. 1 h before and concurrently with oral paclitaxel. Blood sampling was performed to evaluate the pharmacokinetics of paclitaxel, 6-alpha-hydroxypaclitaxel, 3-p-hydroxypaclitaxel, and cyclosporin A. The pharmacokinetic behavior of paclitaxel was characterized using both compartmental and noncompartmental methods. Model-estimated parameters were used to simulate paclitaxel concentrations after once daily and twice daily oral administration of paclitaxel and cyclosporin A. Aside from an unpleasant taste, the oral regimen was well tolerated, and there were no grade 3 or 4 drug-related toxicities. The systemic exposure to paclitaxel, as assessed by maximum plasma concentration (Cmax) and area under the plasma concentration versus time curve (AUC) values, did not increase as the dose of paclitaxel was increased from 180 to 540 mg, and there was substantial interindividual variability (4-6-fold) at each dose level. Mean paclitaxel Cmax values approached plasma concentrations achieved with clinically relevant parenteral dose schedules, averaging 268+/-164 ng/ml. AUC values averaged 3306+/-1977 ng x h/ ml, which was significantly lower than AUC values achieved with clinically relevant i.v. paclitaxel dose schedules. However, computer simulations using pharmacokinetic parameters derived from the present study demonstrated that pharmacodynamically relevant steady-state plasma paclitaxel concentrations of at least 0.06 microM would be achieved after protracted once daily and twice daily dosing with oral paclitaxel and cyclosporin A. Paclitaxel metabolites were detectable in three patients, and the 6-alpha-hydroxypaclitaxel: paclitaxel and 3-p-hydroxypaclitaxel:paclitaxel AUC ratios averaged 0.63 and 0.86, respectively; these values were substantially higher than values reported in patients treated with i.v. paclitaxel. Oral paclitaxel was bioavailable in humans when administered in combination with oral cyclosporin A 5 mg/kg 1 h before and concurrently with paclitaxel treatment, and plasma paclitaxel concentrations achieved with this schedule were biologically relevant and approached concentrations attained with clinically relevant parenteral dose schedules. However, treatment of patients with oral paclitaxel using a single oral dose administration schedule failed to achieve sufficiently high systemic drug exposure and pharmacodynamic effects. In contrast, computer simulations demonstrated that clinically relevant pharmacodynamic effects are likely to be achieved with multiple once daily and twice daily oral paclitaxel-cyclosporin A dosing schedules. PMID:10999729

Britten, C D; Baker, S D; Denis, L J; Johnson, T; Drengler, R; Siu, L L; Duchin, K; Kuhn, J; Rowinsky, E K

2000-09-01

28

Aptamer conjugated paclitaxel and magnetic fluid loaded fluorescently tagged PLGA nanoparticles for targeted cancer therapy  

NASA Astrophysics Data System (ADS)

Controlled and targeted drug delivery is an essential criterion in cancer therapy to reduce the side effects caused by non-specific drug release and toxicity. Targeted chemotherapy, sustained drug release and optical imaging have been achieved using a multifunctional nanocarrier constructed from poly (D, L-lactide-co-glycolide) nanoparticles (PLGA NPs), an anticancer drug paclitaxel (PTX), a fluorescent dye Nile red (NR), magnetic fluid (MF) and aptamers (Apt, AS1411, anti-nucleolin aptamer). The magnetic fluid and paclitaxel loaded fluorescently labeled PLGA NPs (MF-PTX-NR-PLGA NPs) were synthesized by a single-emulsion technique/solvent evaporation method using a chemical cross linker bis (sulfosuccinimidyl) suberate (BS3) to enable binding of aptamer on to the surface of the nanoparticles. Targeting aptamers were then introduced to the particles through the reaction with the cross linker to target the nucleolin receptors over expressed on the cancer cell surface. Specific binding and uptake of the aptamer conjugated magnetic fluid loaded fluorescently tagged PLGA NPs (Apt-MF-NR-PLGA NPs) to the target cancer cells induced by aptamers was observed using confocal microscopy. Cytotoxicity assay conducted in two cell lines (L929 and MCF-7) confirmed that targeted MCF-7 cancer cells were killed while control cells were unharmed. In addition, aptamer mediated delivery resulting in enhanced binding and uptake to the target cancer cells exhibited increased therapeutic effect of the drug. Moreover, these aptamer conjugated magnetic polymer vehicles apart from actively transporting drugs into specifically targeted tumor regions can also be used to induce hyperthermia or for facilitating magnetic guiding of particles to the tumor regions.

Aravind, Athulya; Nair, Remya; Raveendran, Sreejith; Veeranarayanan, Srivani; Nagaoka, Yutaka; Fukuda, Takahiro; Hasumura, Takahashi; Morimoto, Hisao; Yoshida, Yasuhiko; Maekawa, Toru; Sakthi Kumar, D.

2013-10-01

29

Thermoreversible liposomal poloxamer gel for the delivery of paclitaxel: dose proportionality and hematological toxicity studies.  

PubMed

The currently existing treatment modalities of cancer suffer from a major drawback of systemic toxicity, which results from high systemic drug exposure. Delivery of chemotherapeutic agents by delivery systems that alleviate systemic side effects but at the same time provide therapeutic advantage by controlling tumor growth exists as a viable option. To achieve this objective, a thermo reversible poloxamer gel containing paclitaxel incorporated in liposomes was formulated at three dose loadings. These paclitaxel loaded formations were injected subcutaneously (s.c.) in Sprague Dawley rats. Blood samples collected at various time points were used in the determination of drug concentration as well as white blood cell and neutrophil counts for the estimation of systemic toxicity of the formulation. Absorption of paclitaxel after s.c. injection occurred slowly with prominence of absorption phase in plasma profile, suggesting presence of flip-flop pharmacokinetics. In spite of increase in dose of paclitaxel administered, no statistically significant increase in plasma levels and pharmacokinetic parameters occurred. Further, no significant increase in hematological toxicity was observed with increased drug exposure to animals. These results show that liposomal poloxamer gels reduce systemic toxicity of paclitaxel even at high doses; and thus, can serve as an effective delivery system for alleviating body burden of this toxic chemotherapeutic agent. PMID:18604987

Dhanikula, R S; Dhanikula, A B; Panchagnula, R

2008-06-01

30

Targeted Paclitaxel by conjugation to iron oxide and gold nanoparticles.  

PubMed

The Fe(3)O(4) nanoparticles, tailored with maleimidyl 3-succinimidopropionate ligands, were conjugated with paclitaxel molecules that were attached with a poly(ethylene glycol) (PEG) spacer through a phosphodiester moiety at the (C-2')-OH position. The average number of paclitaxel molecules/nanoparticles was determined as 83. These nanoparticles liberated paclitaxel molecules upon exposure to phosphodiesterase. PMID:19072111

Hwu, Jih Ru; Lin, Yu Sern; Josephrajan, Thainashmuthu; Hsu, Ming-Hua; Cheng, Fong-Yu; Yeh, Chen-Sheng; Su, Wu-Chou; Shieh, Dar-Bin

2009-01-14

31

Ultrasound activated paclitaxel delivery in mice using a combined therapy and imaging probe system  

Microsoft Academic Search

Localized therapeutic effects of an experimental therapeutic agent on a mouse MC38 tumor model were evaluated using a combined ultrasound therapy and imaging probe system (TIPS). With ultrasound activated paclitaxel delivery, the tumor growth is substantially retarded for at least 3 days. The therapeutic effect of ultrasound is statistically significant (p=0.03) within one day after treatment but gradually decreases with

William T. Shi; Marcel Böhmer; Muzaffer Celebi; Annemieke van Wamel; Chien Ting Chin; Ceciel Chlon; Alexander L. Klibanov; Christopher S. Hall

2008-01-01

32

Paclitaxel-liposome-microbubble complexes as ultrasound-triggered therapeutic drug delivery carriers.  

PubMed

Liposome-microbubble complexes (LMC) have become a promising therapeutic carrier for ultrasound-triggered drug delivery to treat malignant tumors. However, the efficacy for ultrasound-assisted chemotherapy in vivo and the underlying mechanisms remain to be elucidated. Here, we investigated the feasibility of using paclitaxel-liposome-microbubble complexes (PLMC) as possible ultrasound (US)-triggered targeted chemotherapy against breast cancer. PTX-liposomes (PL) were conjugated to the microbubble (MB) surface through biotin-avidin linkage, increasing the drug-loading efficiency of MBs. The significant increased release of payloads from liposome-microbubble complexes was achieved upon US exposure. We used fluorescent quantum dots (QDs) as a model drug to show that released QDs were taken up by 4T1 breast cancer cells treated with QD-liposome-microbubble complexes (QLMC) and US, and uptake depended on the exposure time and intensity of insonication. We found that PLMC plus US inhibited tumor growth more effectively than PL plus US or PLMC without US, not only in vitro, but also in vivo. Histologically, the inhibition of tumor growth appeared to result from increased apoptosis and reduced angiogenesis in tumor xenografts. In addition, a significant increase of drug concentration in tumors was observed in comparison to treatment with non-conjugated PL or PLMC without US. The significant increase in an antitumor efficacy of PLMC plus US suggests their potential use as a new targeted US chemotherapeutic approach to inhibit breast cancer growth. PMID:23306023

Yan, Fei; Li, Lu; Deng, Zhiting; Jin, Qiaofeng; Chen, Juanjuan; Yang, Wei; Yeh, Chih-Kuang; Wu, Junru; Shandas, Robin; Liu, Xin; Zheng, Hairong

2013-01-07

33

Electrospun Micro and Nanofibers for Sustained Delivery of Paclitaxel to Treat C6 Glioma in Vitro  

Microsoft Academic Search

Purpose  The present study aims to develop electrospun PLGA-based micro- and nanofibers as implants for the sustained delivery of anticancer drug to treat C6 glioma in vitro.Methods  PLGA and an anticancer drug—paclitaxel-loaded PLGA micro- and nanofibers were fabricated by electrospinning and the key processing parameters were investigated. The physical and chemical properties of the micro- and nanofibers were characterized by various state-of-the-art

Jingwei Xie; Chi-Hwa Wang

2006-01-01

34

COLON TARGETED DRUG DELIVERY SYSTEMS  

Microsoft Academic Search

Colon targeted drug delivery systems have the potential to deliver drugs for the treatment of a variety of colonic diseases and to deliver proteins and peptides to the colon for their systemic absorption. In recent years, various pharmaceutical approaches have been developed for targeting the drugs to the colon include, formation of prodrugs, coating of pH-sensitive polymers, use of colon

Ceyda Tuba

35

In vivo prevention of arterial restenosis with paclitaxel-encapsulated targeted lipid-polymeric nanoparticles  

PubMed Central

Following recent successes with percutaneous coronary intervention (PCI) for treating coronary artery disease (CAD), many challenges remain. In particular, mechanical injury from the procedure results in extensive endothelial denudation, exposing the underlying collagen IV-rich basal lamina, which promotes both intravascular thrombosis and smooth muscle proliferation. Previously, we reported the engineering of collagen IV-targeting nanoparticles (NPs) and demonstrated their preferential localization to sites of arterial injury. Here, we develop a systemically administered, targeted NP system to deliver an antiproliferative agent to injured vasculature. Approximately 60-nm lipid–polymeric NPs were surface functionalized with collagen IV-targeting peptides and loaded with paclitaxel. In safety studies, the targeted NPs showed no signs of toxicity and a ?3.5-fold improved maximum tolerated dose versus paclitaxel. In efficacy studies using a rat carotid injury model, paclitaxel (0.3 mg/kg or 1 mg/kg) was i.v. administered postprocedure on days 0 and 5. The targeted NP group resulted in lower neointima-to-media (N/M) scores at 2 wk versus control groups of saline, paclitaxel, or nontargeted NPs. Compared with sham-injury groups, an ?50% reduction in arterial stenosis was observed with targeted NP treatment. The combination of improved tolerability, sustained release, and vascular targeting could potentially provide a safe and efficacious option in the management of CAD.

Chan, Juliana M.; Drum, Chester L.; Bronson, Roderick T.; Golomb, Gershon; Langer, Robert; Farokhzad, Omid C.

2011-01-01

36

Effects of local intracoronary paclitaxel delivery using the Remedy transport catheter on neointimal hyperplasia after stent implantation in a porcine model  

Microsoft Academic Search

PurposeTo assess the effects of local paclitaxel delivery using the Remedy catheter on neointimal hyperplasia in a porcine model and compare these results to commercially available BMS and biodegradable polymer-coated paclitaxel-eluting stents (BP-PES).

Krzysztof Milewski; Aleksander Zurakowski; Jacek Pajak; Lukasz Liszka; Marcin Debinski; Piotr P. Buszman; Motaz Abu Samra; Piotr Dominek; Michael S. Aboodi; Grzegorz L. Kaluza; Pawel Buszman

2011-01-01

37

Formulation and pharmacokinetic evaluation of a paclitaxel nanosuspension for intravenous delivery  

PubMed Central

Paclitaxel is a diterpenoid isolated from Taxus brevifolia. It is effective for various cancers, especially ovarian and breast cancer. Due to its aqueous insolubility, it is administered dissolved in ethanol and Cremophor® EL (BASF, Ludwigshafen, Germany), which can cause serious allergic reactions. In order to eliminate Cremophor EL, paclitaxel was formulated as a nanosuspension by high-pressure homogenization. The nanosuspension was lyophilized to obtain the dry paclitaxel nanoparticles (average size, 214.4 ± 15.03 nm), which enhanced both the physical and chemical stability of paclitaxel nanoparticles. Paclitaxel dissolution was also enhanced by the nanosuspension. Differential scanning calorimetry showed that the crystallinity of paclitaxel was preserved during the high-pressure homogenization process. The pharmacokinetics and tissue distribution of paclitaxel were compared after intravenous administration of paclitaxel nanosuspension and paclitaxel injection. In rat plasma, paclitaxel nanosuspension exhibited a significantly (P < 0.01) reduced area under the concentration curve (AUC)0–? (20.343 ± 9.119 ?g · h · mL?1 vs 5.196 ± 1.426 ?g · h · mL?1), greater clearance (2.050 ± 0.616 L · kg?1 · h?1 vs 0.556 ± 0.190 L · kg?1 · h?1), and shorter elimination half-life (5.646 ± 2.941 vs 3.774 ± 1.352 hours) compared with the paclitaxel solution. In contrast, the paclitaxel nanosuspension resulted in a significantly greater AUC0–? in liver, lung, and spleen (all P < 0.01), but not in heart or kidney.

Wang, Yonglu; Li, Xueming; Wang, Liyao; Xu, Yuanlong; Cheng, Xiaodan; Wei, Ping

2011-01-01

38

Enhanced Oral Absorption of Paclitaxel in a Novel Self-Microemulsifying Drug Delivery System with or Without Concomitant Use of P-Glycoprotein Inhibitors  

Microsoft Academic Search

Purpose. The objective of this study was to evaluate the pharmacokinetics of paclitaxel in a novel self-microemulsifying drug delivery system (SMEDDS) for improved oral administration with or without P-glycoprotein (P-gp) inhibitors.

Shicheng Yang; R. Neslihan Gursoy; Gregory Lambert; Simon Benita

2004-01-01

39

Integrin Targeted Delivery of Radiotherapeutics  

PubMed Central

Targeted radionuclide therapy, which is based on the selective delivery of a sufficient radiation dose to tumors without significantly affecting normal tissues, is a promising therapeutic approach for the treatment of a wide variety of malignancies. Integrins, a family of cell adhesion molecules, play key roles during tumor angiogenesis and metastasis. Among all the integrins, ?v?3 seems to be the most important in the process of tumor angiogenesis. Integrin ?v?3 is highly expressed on activated endothelial cells, new-born vessels as well as some tumor cells, but is not present in resting endothelial cells and most normal organ systems, making it a suitable target for anti-tumor therapy. In this review, we summarize the current development and applications of antibody-, peptide-, and other ligand-based integrin targeted radiotherapeutics for tumor radiation therapy.

Liu, Zhaofei; Wang, Fan; Chen, Xiaoyuan

2011-01-01

40

Dendritic poly(ethylene glycol) bearing paclitaxel and alendronate for targeting bone neoplasms.  

PubMed

Poly(ethylene glycol) (PEG) is the most popular polymer for protein conjugation, but its potential as carrier of low molecular weight drugs has been limited by the intrinsic low loading, owing to its chemical structure. In fact, only the two end chain groups of PEG can be modified and exploited for drug coupling. We have demonstrated that by synthesizing a dendrimer structure at the polymer end chains, it is possible to increase the drug payload and overcome this limitation. Furthermore, this approach can be improved by using heterobifunctional PEG. These polymers allow the precise linking of two different drugs, or a drug and a targeting agent, on the same polymeric chain. Heterobifunctional PEG-dendrimers have been obtained with defined chemical structures leading to their attractive use as drug delivery systems. In fact, they offer a double benefit; first, the possibility to choose the best drug/targeting agent ratio, and second, the separation of the two functions, activity and targeting, which are coupled at the opposite polymer end chains. In this study, we investigated the role of a PEG-dendrimer, H(2)N-PEG-dendrimer-(COOH)(4), as carrier for a combination of paclitaxel (PTX) and alendronate (ALN). PTX is a potent anticancer drug that is affected by severe side effects originating from both the drug itself and its solubilizing formulation, Cremophor EL. ALN is an aminobiphosphonate used for the treatment of osteoporosis and bone metastases as well as a bone-targeting moiety. The PTX-PEG-ALN conjugate was designed to exploit active targeting by the ALN molecule and passive targeting through the enhanced permeability and retention (EPR) effect. Our conjugate demonstrated a great binding affinity to the bone mineral hydroxyapatite in vitro and an IC(50) comparable to that of the free drugs combination in human adenocarcinoma of the prostate (PC3) cells. The PTX-PEG-ALN conjugate exhibited an improved pharmacokinetic profile compared with the free drugs owed to the marked increase in their half-life. In addition, PTX-PEG-ALN could be solubilized directly in physiological solutions without the need for Cremophor EL. The data presented in this manuscript encourage further investigations on the potential of PTX-PEG-ALN as treatment for cancer bone metastases. PMID:21608527

Clementi, Chiara; Miller, Keren; Mero, Anna; Satchi-Fainaro, Ronit; Pasut, Gianfranco

2011-05-24

41

Effective Drug Delivery, in vitro and in vivo, By Carbon-Based Nanovectors Non-Covalently Loaded With Unmodified Paclitaxel  

PubMed Central

Many new drugs have low aqueous solubility and high therapeutic efficacy. Paclitaxel (PTX) is a classic example of this type of compound. Here we show that extremely small (<40 nm) hydrophilic carbon clusters (HCCs) that are PEGylated (PEG-HCCs) are effective drug delivery vehicles when simply mixed with paclitaxel. This formulation of PTX sequestered in PEG-HCCs (PTX/PEG-HCCs) is stable for at least twenty weeks. The PTX/PEG-HCCs formulation was as effective as PTX in a clinical formulation in reducing tumor volumes in an orthotopic murine model of oral squamous cell carcinoma. Preliminary toxicity and biodistribution studies suggest that the PEG-HCCs are not acutely toxic and, like many other nanomaterials, are primarily accumulated in the liver and spleen. This work demonstrates that carbon nanomaterials are effective drug delivery vehicles in vivo when non-covalently loaded with an unmodified drug.

Berlin, Jacob M.; Leonard, Ashley D.; Pham, Tam T.; Sano, Daisuke; Marcano, Daniela C.; Yan, Shayou; Fiorentino, Stefania; Milas, Zvonimir L.; Kosynkin, Dmitry V.; Katherine Price, B.; Lucente-Schultz, Rebecca M.; Wen, XiaoXia; Gabriela Raso, M.; Craig, Suzanne L.; Tran, Hai T.; Myers, Jeffrey N.; Tour, James M.

2010-01-01

42

Effective drug delivery, in vitro and in vivo, by carbon-based nanovectors noncovalently loaded with unmodified Paclitaxel.  

PubMed

Many new drugs have low aqueous solubility and high therapeutic efficacy. Paclitaxel (PTX) is a classic example of this type of compound. Here we show that extremely small (<40 nm) hydrophilic carbon clusters (HCCs) that are PEGylated (PEG-HCCs) are effective drug delivery vehicles when simply mixed with paclitaxel. This formulation of PTX sequestered in PEG-HCCs (PTX/PEG-HCCs) is stable for at least 20 weeks. The PTX/PEG-HCCs formulation was as effective as PTX in a clinical formulation in reducing tumor volumes in an orthotopic murine model of oral squamous cell carcinoma. Preliminary toxicity and biodistribution studies suggest that the PEG-HCCs are not acutely toxic and, like many other nanomaterials, are primarily accumulated in the liver and spleen. This work demonstrates that carbon nanomaterials are effective drug delivery vehicles in vivo when noncovalently loaded with an unmodified drug. PMID:20681596

Berlin, Jacob M; Leonard, Ashley D; Pham, Tam T; Sano, Daisuke; Marcano, Daniela C; Yan, Shayou; Fiorentino, Stefania; Milas, Zvonimir L; Kosynkin, Dmitry V; Price, B Katherine; Lucente-Schultz, Rebecca M; Wen, Xiaoxia; Raso, M Gabriela; Craig, Suzanne L; Tran, Hai T; Myers, Jeffrey N; Tour, James M

2010-08-24

43

Poly(vinyl alcohol)-graft-poly(lactide-co-glycolide) nanoparticles for local delivery of paclitaxel for restenosis treatment  

Microsoft Academic Search

Catheter-based local delivery of biodegradable nanoparticles (NP) with sustained release characteristics represents a therapeutic approach to reduce restenosis. Paclitaxel-loaded NP consisting of poly(vinyl alcohol)-graft-poly(lactide-co-glycolide) (PVA-g-PLGA) with varying PLGA chain length as well as poly(lactide-co-glycolide) (PLGA), were prepared by a solvent evaporation technique. NP of <180 nm in diameter characterized by photon correlation spectroscopy (PCS), scanning electron microscopy (SEM), and atomic force

Ulrich Westedt; Marc Kalinowski; Matthias Wittmar; Thomas Merdan; Florian Unger; Jutta Fuchs; Susann Schäller; Udo Bakowsky; Thomas Kissel

2007-01-01

44

THE USE OF NANOPARTICLE-MEDIATED TARGETED GENE SILENCING AND DRUG DELIVERY TO OVERCOME TUMOR DRUG RESISTANCE  

PubMed Central

Overexpression of drug efflux transporters such as P-glycoprotein (P-gp) enables cancer cells to develop resistance to multiple anticancer drugs. Functional inhibitors of P-gp have shown promising efficacy in early clinical trials, but their long-term safety is yet to be established. A novel approach to overcome drug resistance is to use siRNA-mediated RNA interference to silence the expression of the efflux transporter. Because P-gp plays an important role in the physiological regulation of endogenous and xenobiotic compounds in the body, it is important to deliver P-gp targeted siRNA and anticancer drug specifically to tumor cells. Further, for optimal synergy, both the drug and siRNA may need to be temporally colocalized in the tumor cells. In the current study, we investigated the effectiveness of simultaneous and targeted delivery of anticancer drug, paclitaxel, along with P-gp targeted siRNA, using poly(D,L-lactide-co-glycolide) nanoparticles to overcome tumor drug resistance. Nanoparticles were surface functionalized with biotin for active tumor targeting. Dual agent nanoparticles encapsulating the combination of paclitaxel and P-gp targeted siRNA showed significantly higher cytotoxicity in vitro than nanoparticles loaded with paclitaxel alone. Enhanced therapeutic efficacy of dual agent nanoparticles could be correlated with effective silencing of the MDR1 gene that encodes for P-gp and with increased accumulation of paclitaxel in drug-resistant tumor cells. In vivo studies in a mouse model of drug-resistant tumor demonstrated significantly greater inhibition of tumor growth following treatment with biotin-functionalized nanoparticles encapsulating both paclitaxel and P-gp targeted siRNA at a paclitaxel dose that was ineffective in the absence of gene silencing. These results suggest that that the combination of P-gp gene silencing and cytotoxic drug delivery using targeted nanoparticles can overcome tumor drug resistance.

Patil, Yogesh; Swaminathan, Suresh; Sadhukha, Tanmoy; Ma, Linan; Panyam, Jayanth

2009-01-01

45

Well-defined degradable brush polymer-drug conjugates for sustained delivery of Paclitaxel.  

PubMed

To achieve a conjugated drug delivery system with high drug loading but minimal long-term side effects, a degradable brush polymer-drug conjugate (BPDC) was synthesized through azide-alkyne click reaction of acetylene-functionalized polylactide (PLA) with azide-functionalized paclitaxel (PTXL) and poly(ethylene glycol) (PEG). Well-controlled structures of the resulting BPDC and its precursors were verified by (1)H NMR and gel permeation chromatography (GPC) characterizations. With nearly quantitative click efficiency, drug loading amount of the BPDC reached 23.2 wt %. Both dynamic light scattering (DLS) analysis and transmission electron microscopy (TEM) imaging indicated that the BPDC had a nanoscopic size around 10-30 nm. The significant hydrolytic degradability of the PLA backbone of the BPDC was confirmed by GPC analysis of its incubated solution. Drug release study showed that PTXL moieties can be released through the cleavage of the hydrolyzable conjugation linkage in pH 7.4 at 37 °C, with 50% release in about 22 h. As illustrated by cytotoxicity study, while the polymeric scaffold of the BPDC is nontoxic, the BPDC exhibited higher therapeutic efficacy toward MCF-7 cancer cells than free PTXL at 0.1 and 1 ?g/mL. Using Nile red as encapsulated fluorescence probe, cell uptake study showed effective internalization of the BPDC into the cells. PMID:23181264

Yu, Yun; Chen, Chih-Kuang; Law, Wing-Cheung; Mok, Jorge; Zou, Jiong; Prasad, Paras N; Cheng, Chong

2012-12-07

46

Controlled preparation and antitumor efficacy of vitamin E TPGS-functionalized PLGA nanoparticles for delivery of paclitaxel.  

PubMed

Vitamin E TPGS-functionalized polymeric nanoparticles have been developed as a promising drug delivery platform in recent years. Obtaining reproducible monodisperse TPGS/polymeric nanoparticles with high encapsulation efficiency (EE%) still remains a big challenge. In this study, an inverse-phase nanoprecipitation method was developed to synthesize TPGS-functionalized PLGA nanoparticles (TPNs) for controlled release of paclitaxel (PTX). To take advantages of lipids, a part of TPGS in the TPNs was replaced by lipids. The results showed that with weight ratio of TPGS-to-PLGA of 2-3 and a molar replacement of lecithin ratio of 30%, the PTX-loaded TPNs (PTPNs) and PTX-loaded lipid-containing TPNs (PLTPNs) exhibited controllable and nearly uniform size of 130-150nm and EE% of over 80%. Compared to Taxol(®), both the PTPNs and PLTPNs significantly increased the intracellular uptake and exerted strong inhibitory effect on human lung cancer A549 model cells. Furthermore, a selective accumulation to tumor site and significant antitumor efficacy of TPNs in the A549 lung cancer xenografted nude mice were observed by intravenous administration, especially for the PTPNs group. Our data suggested that the inverse-phase nanoprecipitation method holds great potential for the fabrication of the paclitaxel-loaded TPNs and the TPNs prepared here is a promising controllable delivery system for paclitaxel. PMID:23402977

Wang, Guoying; Yu, Bo; Wu, Yuequn; Huang, Baolin; Yuan, Yuan; Liu, Chang Sheng

2013-02-10

47

Membranes and Barriers: Targeted Drug Delivery.  

National Technical Information Service (NTIS)

Contents: Retrometabolic Approaches to Drug Targeting; Vector-Mediated Delivery of Opioid Peptides to the Brain; Conformationally Constrained Peptide Drugs Targeted at the Blood-Brain Barrier; Passive and Facilitative Transport of Nucleobases, Nucleosides...

R. S. Rapaka

1995-01-01

48

Intratumoral delivery of paclitaxel using a thermosensitive hydrogel in human tumor xenografts.  

PubMed

Poly(organophosphazene), a novel thermosensitive hydrogel, is an injectable drug delivery system (DDS) that transforms from sol to gel at body temperature. Paclitaxel (PTX) is a mitotic inhibitor used in the treatment of various solid tumors. Due to its poor solubility in water and efflux systems in the gastrointestinal tract, PTX is a good candidate for local DDS. Here, we evaluated the penetration kinetics of PTX released from the PTX-poly(organophosphazene) hydrogel mixture in multicellular layers (MCLs) of human cancer cells. We also investigated the tumor pharmacokinetics of PTX (60 mg/kg) when administered as an intratumoral injection using poly(organophosphazene) in mice with human tumor xenografts. When PTX was formulated at 0.6 % w/w into a 10 % w/w hydrogel, the in vitro and in vivo release were found to be 40 and 90 % of the dose, respectively, in a sustained manner over 4 weeks. Exposure of MCLs to PTX-hydrogel showed time-dependent drug penetration and accumulation. In mice, the hydrogel mass was well retained over 6 weeks, and the PTX concentration in the tumor tissue was maximal at 14 days, which rapidly decreased and coincided with rebound tumor growth after 14 days of suppression. These data indicate that PTX-hydrogel should be intratumorally injected every 14 days, or drug release duration should be prolonged in order to achieve a long-term antitumor effect. Overall, poly(organophosphazene) represents a novel thermosensitive DDS for intratumoral delivery of PTX, which can accommodate a large dose of the drug in addition to reducing its systemic exposure by restricting biodistribution to tumor tissue alone. PMID:23371803

Kim, Jung Ho; Lee, Joo-Ho; Kim, Kwang-Suck; Na, Kun; Song, Soo-Chang; Lee, Jaehwi; Kuh, Hyo-Jeong

2013-01-01

49

Applying models of targeted drug delivery to gene delivery.  

PubMed

Gene delivery requires targeted delivery systems. Exploratory simulations using models of targeted drug delivery helps one assess the worthiness of such systems, and helps quantify the expected therapeutic benefits of the systems. The drug targeting index (DTI), a ratio of availabilities, is a measure of pharmacokinetic benefit of the delivery device, based on a combination of a physiologically-based pharmacokinetic model and a single pharmacodynamic Emaxmodel. Pharmacodynamic outcomes are quantified by the degree of separation between the dose-response and dose-toxicity curves (SRT). Simulations are undertaken to investigate the potential linkage of DTI and SRT, a pharmacodynamic outcome. A significant positive linear relationship is found between the DTI and SRT. The relationship can be translated into a minimum pharmacokinetic requirement that can be used to guide making decisions regarding whether or not further pursue the development of a candidate gene-delivery device as a therapeutic agent. PMID:17271053

Lam, Tai Ning; Hunt, C Anthony

2004-01-01

50

Enhancement of the targeting capabilities of the Paclitaxel-loaded pluronic nanoparticles with a glycol chitosan/heparin composite.  

PubMed

An enhancement of tumor-targeting capability was demonstrated with paclitaxel (PTX)-loaded Pluronic nanoparticles (NPs) with immobilized glycol chitosan and heparin. The PTX-loaded Pluronic NPs were prepared as described in our previous report by means of a temperature-induced phase transition in a mixture of Pluronic F-68 and liquid polyethylene glycol (PEG; molecular weight: 400) containing PTX. The liquid PEG is used as the solubilizer of PTX, and Pluronic F-68 is the polymer that encapsulates the PTX. The glycol chitosan and heparin were immobilized on the surface of the Pluronic NPs in an aqueous medium, and a powdery form of the glycol chitosan/heparin immobilized Pluronic NPs (composite NPs) was obtained by freeze-drying. Field emission scanning electron microscopy and a particle size analyzer were used to observe the morphology and size distribution of the prepared NPs. To apply the composite NPs as a delivery system for the model anticancer drug PTX, the release pattern and pharmacokinetic parameters were observed, and the tumor growth was monitored by injecting the composite NPs into the tail veins of tumor-bearing mice. An enhancement of tumor-targeting capability of NPs was verified by using noninvasive live animal imaging technology to observe the time-dependent excretion profile, the in vivo biodistribution, circulation time, and the tumor-targeting capability of composite NPs. PMID:22149139

Yuk, Soon Hong; Oh, Keun Sang; Cho, Sun Hang; Kim, Sang Yoon; Oh, Sangkwon; Lee, Jin Ho; Kim, Kwangmeyung; Kwon, Ick Chan

2011-12-23

51

The ClC-3 chloride channel associated with microtubules is a target of paclitaxel in its induced-apoptosis.  

PubMed

Recent evidences show that cationic fluxes play a pivotal role in cell apoptosis. In this study, the roles of Cl(-) channels in paclitaxel-induced apoptosis were investigated in nasopharyngeal carcinoma CNE-2Z cells. Chloride current and apoptosis were induced by paclitaxel and inhibited by chloride channel blockers. Paclitaxel-activated current possessed similar properties to volume-activated chloride current. After ClC-3 was knocked-down by ClC-3-siRNA, hypotonicity-activated and paclitaxel-induced chloride currents were obviously decreased, indicating that the chloride channel involved in paclitaxel-induced apoptosis may be ClC-3. In early apoptotic cells, ClC-3 was up-regulated significantly; over-expressed ClC-3 was accumulated in cell membrane to form intercrossed filaments, which were co-localized with ?-tubulins; changes of ultrastructures and decrease of flexibility in cell membrane were detected by atomic force microscopy. These suggest that ClC-3 is a critical target of paclitaxel and the involvement of ClC-3 in apoptosis may be associated with its accumulation with membrane microtubules and its over activation. PMID:24026363

Zhang, Haifeng; Li, Huarong; Yang, Lili; Deng, Zhiqin; Luo, Hai; Ye, Dong; Bai, Zhiquan; Zhu, Linyan; Ye, Wencai; Wang, Liwei; Chen, Lixin

2013-09-12

52

The ClC-3 chloride channel associated with microtubules is a target of paclitaxel in its induced-apoptosis  

PubMed Central

Recent evidences show that cationic fluxes play a pivotal role in cell apoptosis. In this study, the roles of Cl? channels in paclitaxel-induced apoptosis were investigated in nasopharyngeal carcinoma CNE-2Z cells. Chloride current and apoptosis were induced by paclitaxel and inhibited by chloride channel blockers. Paclitaxel-activated current possessed similar properties to volume-activated chloride current. After ClC-3 was knocked-down by ClC-3-siRNA, hypotonicity-activated and paclitaxel-induced chloride currents were obviously decreased, indicating that the chloride channel involved in paclitaxel-induced apoptosis may be ClC-3. In early apoptotic cells, ClC-3 was up-regulated significantly; over-expressed ClC-3 was accumulated in cell membrane to form intercrossed filaments, which were co-localized with ?-tubulins; changes of ultrastructures and decrease of flexibility in cell membrane were detected by atomic force microscopy. These suggest that ClC-3 is a critical target of paclitaxel and the involvement of ClC-3 in apoptosis may be associated with its accumulation with membrane microtubules and its over activation.

Zhang, Haifeng; Li, Huarong; Yang, Lili; Deng, Zhiqin; Luo, Hai; Ye, Dong; Bai, Zhiquan; Zhu, Linyan; Ye, Wencai; Wang, Liwei; Chen, Lixin

2013-01-01

53

Specific tumor delivery of paclitaxel using glycolipid-like polymer micelles containing gold nanospheres.  

PubMed

It is difficult for most of the drug delivery systems to really display a temporal and spatial release of entrapped drug once the systems are iv administrated. We hypothesized that the photothermal effect, mediated by a near-infrared (NIR) laser and hollow gold nanospheres (HAuNS), can modulate paclitaxel (PTX) release from polymer micelles, and further result in the enhanced antitumor activity of the micelles. We loaded PTX and HAuNS, which display strong plasmon absorption in the NIR region, into glycolipid-like polymer micelles with an excellent cell internalization capability. The surface of the micelles was conjugated successfully with a peptide, which has the specific-binding with EphB4, a member of the Eph family of receptor tyrosine kinases overexpressed on cell membrane of numerous tumors, to increase the delivery of PTX into tumor cells. Rapid and repetitive drug release from our polymer (HP-TCS) micelles could be readily achieved upon NIR laser irradiation. Our data demonstrated the specific delivery of HP-TCS micelles into positive-EphB4 tumors using a duel-tumor model after iv administration during the whole experiment process (1-48 h). Interestingly, significantly higher uptake of the micelles by SKOV3 tumors (positive-EphB4) than A549 tumors (negtive-EphB4) was observed, with increased ratio on experiment time. However, the specific cell uptake was observed only during the short incubation time (1-4 h) in vitro. Our data also indicated the treatment of tumor cells with the micelles followed by NIR laser irradiation showed significantly greater toxicity activity than the treatment with the micelles alone, free PTX and the micelles (without PTX loading) plus NIR laser irradiation. The enhanced toxicity activity to tumor cells should be attributed to the enhanced drug cellular uptake mediated by the glycolipid-like micelles, chemical toxicity of the released drug from the micelles due to the trigger of NIR laser, and the photothermal ablation under NIR laser irradiation. PMID:23510855

You, Jian; Wang, Zuhua; Du, Yongzhong; Yuan, Hong; Zhang, Peizun; Zhou, Jialin; Liu, Fei; Li, Chun; Hu, Fuqiang

2013-03-16

54

Paclitaxel inhibits killing by murine cytotoxic T lymphocytes in vivo but not in vitro  

Microsoft Academic Search

To kill antigen-specific target cells (TCs), cytotoxic T lymphocytes (CTLs) reorganise their microtubule cytoskeleton to deliver lytic granules to the TCs. We used two drugs that stabilise microtubules, paclitaxel and peloruside, to determine how the stabilising microtubule network affects CTL function in vitro and in vivo. In vitro, neither paclitaxel nor peloruside inhibited antigen-specific killing, lytic granule delivery to the

Marcus James Robinson; Franca Ronchese; John H Miller; Anne Camille La Flamme; AC La Flamme

2010-01-01

55

Targeted Delivery Systems for Oligonucleotide Therapeutics  

Microsoft Academic Search

Oligonucleotides including antisense oligonucleotides and siRNA are emerging as promising therapeutic agents against a variety\\u000a of diseases. Effective delivery of these molecules is critical to their successful clinical application. Targeted systems\\u000a can greatly improve the efficiency and specificity of oligonucleotides delivery. Meanwhile, an effective delivery system must\\u000a successfully overcome a multitude of biological barriers to enable the oligonucleotides to reach

Bo Yu; Xiaobin Zhao; L. James Lee; Robert J. Lee

2009-01-01

56

Polymers for colon targeted drug delivery.  

PubMed

The colon targeted drug delivery has a number of important implications in the field of pharmacotherapy. Oral colon targeted drug delivery systems have recently gained importance for delivering a variety of therapeutic agents for both local and systemic administration. Targeting of drugs to the colon via oral administration protect the drug from degradation or release in the stomach and small intestine. It also ensures abrupt or controlled release of the drug in the proximal colon. Various drug delivery systems have been designed that deliver the drug quantitatively to the colon and then trigger the release of drug. This review will cover different types of polymers which can be used in formulation of colon targeted drug delivery systems. PMID:21969739

Rajpurohit, H; Sharma, P; Sharma, S; Bhandari, A

2010-11-01

57

Non-Covalent Functionalization of Carbon Nanovectors with an Antibody Enables Targeted Drug Delivery  

PubMed Central

Current chemotherapeutics are characterized by efficient tumor cell-killing and severe side effects mostly derived from off target toxicity. Hence targeted delivery of these drugs to tumor cells is actively sought. We previously demonstrated that poly(ethylene glycol)-functionalized carbon nanovectors are able to sequester paclitaxel, a widely used hydrophobic cancer drug, by simple physisorption and deliver the drug for killing of cancer cells. The cell-killing when these drug-loaded carbon nanoparticles were used was equivalent to when a commercial formulation of paclitaxel was used. Here we show that by further mixing the drug-loaded nanoparticles with Cetuximab, a monoclonal antibody that recognizes the epidermal growth factor receptor (EGFR), paclitaxel is preferentially targeted to EGFR+ tumor cells in vitro. This supports progressing to in vivo studies. Moreover, the construct is unusual in that all three components are assembled through non-covalent interactions. Such non-covalent assembly could enable high-throughput screening of drug/antibody combinations.

Berlin, Jacob M.; Pham, Tam T.; Sano, Daisuke; Mohamedali, Khalid A.; Marcano, Daniela C.; Myers, Jeffrey N.; Tour, James M.

2011-01-01

58

Simple approach to stabilized micelles employing miktoarm terpolymers and stereocomplexes with application in paclitaxel delivery.  

PubMed

A simple and versatile approach to miktoarm co- and terpolymers from carbonate functional oligomers is described. The key building block employed is a carboxylic acid functional cyclic carbonate, derived from 2,2-bis(methylol)propionic acid, that was readily coupled to a hydroxyl functional monomethylether poly(ethylene glycol) oligomer. Ring-opening of the cyclic carbonate using functional amines generates a carbamate linkage bearing a functional group capable of initiating either controlled radical or ring-opening polymerization, together with a primary hydroxyl group for ring-opening polymerization. Two tandem polymerization steps were possible which add the second two arms, thus generating the targeted ABC miktoarm terpolymer. The resulting amphiphilic miktoarm terpolymers containing poly(D- and L-lactide) formed polylactide stereocomplexes in the bulk. In aqueous solution, the stereocomplex mixture of Y-shaped miktoarm copolymers, poly(ethylene glycol)-poly(D-lactide)-poly(D-lactide) and poly(ethylene glycol)-poly(L-lactide)-poly(L-lactide), or the stereoblock miktoarm poly(ethylene glycol)-poly(D-lactide)-poly(L-lactide) form stabilized micelles with a significantly lower critical micelle concentration than those derived from conventional stereo regular linear or Y-shaped amphiphiles. This simple and versatile approach provides a useful synthetic route to complex macromolecular architectures that can assemble into stable micelles. These micelles provide high capacity for loading of the anticancer drug paclitaxel and possess narrow size distribution as well as unique structure, leading to sustained and near zero-ordered release of drug without significant initial burst. PMID:19385659

Nederberg, Fredrik; Appel, Eric; Tan, Jeremy P K; Kim, Sung Ho; Fukushima, Kazuki; Sly, Joseph; Miller, Robert D; Waymouth, Robert M; Yang, Yi Yan; Hedrick, James L

2009-06-01

59

Tumor-Targeted Drug Delivery with Aptamers  

PubMed Central

Cancer is one of the leading causes of death around the world. Tumor-targeted drug delivery is one of the major areas in cancer research. Aptamers exhibit many desirable properties for tumor-targeted drug delivery, such as ease of selection and synthesis, high binding affinity and specificity, low immunogenicity, and versatile synthetic accessibility. Over the last several years, aptamers have quickly become a new class of targeting ligands for drug delivery applications. In this review, we will discuss in detail about aptamer-based delivery of chemotherapy drugs (e.g. doxorubicin, docetaxel, daunorubicin, and cisplatin), toxins (e.g. gelonin and various photodynamic therapy agents), and a variety of small interfering RNAs. Although the results are promising which warrants enthusiasm for aptamer-based drug delivery, tumor homing of aptamer-based conjugates after systemic injection has only been achieved in one report. Much remains to be done before aptamer-based drug delivery can reach clinical trials and eventually the day-to-day management of cancer patients. Therefore, future directions and challenges in aptamer-based drug delivery are also discussed.

Zhang, Yin; Hong, Hao; Cai, Weibo

2011-01-01

60

Endocytic mechanisms for targeted drug delivery  

Microsoft Academic Search

Advances in the delivery of targeted drug systems have evolved to enable highly regulated site specific localization to subcellular organelles. Targeting therapeutics to individual intracellular compartments has resulted in benefits to therapies associated with these unique organelles. Endocytosis, a mechanism common to all cells in the body, internalizes macromolecules and retains them in transport vesicles which traffic along the endolysosomal

Lisa M. Bareford; Peter W. Swaan

2007-01-01

61

Mathematical modelling of magnetically targeted drug delivery  

Microsoft Academic Search

A mathematical model for targeted drug delivery using magnetic particles is developed. This includes a diffusive flux of particles arising from interactions between erythrocytes in the microcirculation. The model is used to track particles in a vessel network. Magnetic field design is discussed and we show that it is impossible to specifically target internal regions using an externally applied field.

Andrew D. Grief; Giles Richardson

2005-01-01

62

Effect of Paclitaxel Local Delivery on Neointimal Formation after Endothelial Denudation of the Rat Carotid Artery  

Microsoft Academic Search

Background and Objectives:Mechanisms of restenosis following successful coronary angioplasty (PTCA are known as vascular smooth muscle cells (VSMCs proliferation and migration, elastic recoil or vascular wall remodeling. Paclitaxel whose effect on the stabilization of microtubles leads to cell death is highly lipophilic, permitting easy pass through cell membrane, and has a long-term antiproliferative effect. This study was performed to evaluate

Myeong-Chan Cho; Nam Joo Kwak; Hainan Piao; Tae Jin Youn

63

Targeting the Overproduction of Peroxynitrite for the Prevention and Reversal of Paclitaxel-Induced Neuropathic Pain  

PubMed Central

Chemotherapy-induced peripheral neuropathy (CIPN) accompanied by chronic neuropathic pain is a major dose-limiting side effect of a large number of antitumoral agents including paclitaxel (Taxol). Thus, CIPN is one of most common causes of dose reduction and discontinuation of what is otherwise a life-saving therapy. Neuropathological changes in spinal cord are linked to CIPN, but the causative mediators and mechanisms remain poorly understood. We report that formation of peroxynitrite (PN) in response to activation of nitric oxide synthases and NADPH oxidase in spinal cord contributes to neuropathological changes through two mechanisms. The first involves modulation of neuroexcitatory and proinflammatory (TNF-? and IL-1?) and anti-inflammatory (IL-10 and IL-4) cytokines in favor of the former. The second involves post-translational nitration and modification of glia-derived proteins known to be involved in glutamatergic neurotransmission (astrocyte-restricted glutamate transporters and glutamine synthetase). Targeting PN with PN decomposition catalysts (PNDCs) not only blocked the development of paclitaxel-induced neuropathic pain without interfering with antitumor effects, but also reversed it once established. Herein, we describe our mechanistic study on the role(s) of PN and the prevention of neuropathic pain in rats using known PNDCs (FeTMPyP5+ and MnTE-2-PyP5+). We also demonstrate the prevention of CIPN with our two new orally active PNDCs, SRI6 and SRI110. The improved chemical design of SRI6 and SRI110 also affords selectivity for PN over other reactive oxygen species (such as superoxide). Our findings identify PN as a critical determinant of CIPN, while providing the rationale toward development of superoxide-sparing and “PN-targeted” therapeutics.

Doyle, Timothy; Chen, Zhoumou; Muscoli, Carolina; Bryant, Leesa; Esposito, Emanuela; Cuzzocrea, Salvatore; Dagostino, Concetta; Ryerse, Jan; Rausaria, Smita; Kamadulski, Andrew; Neumann, William L.

2012-01-01

64

Targeting the overproduction of peroxynitrite for the prevention and reversal of paclitaxel-induced neuropathic pain.  

PubMed

Chemotherapy-induced peripheral neuropathy (CIPN) accompanied by chronic neuropathic pain is a major dose-limiting side effect of a large number of antitumoral agents including paclitaxel (Taxol). Thus, CIPN is one of most common causes of dose reduction and discontinuation of what is otherwise a life-saving therapy. Neuropathological changes in spinal cord are linked to CIPN, but the causative mediators and mechanisms remain poorly understood. We report that formation of peroxynitrite (PN) in response to activation of nitric oxide synthases and NADPH oxidase in spinal cord contributes to neuropathological changes through two mechanisms. The first involves modulation of neuroexcitatory and proinflammatory (TNF-? and IL-1?) and anti-inflammatory (IL-10 and IL-4) cytokines in favor of the former. The second involves post-translational nitration and modification of glia-derived proteins known to be involved in glutamatergic neurotransmission (astrocyte-restricted glutamate transporters and glutamine synthetase). Targeting PN with PN decomposition catalysts (PNDCs) not only blocked the development of paclitaxel-induced neuropathic pain without interfering with antitumor effects, but also reversed it once established. Herein, we describe our mechanistic study on the role(s) of PN and the prevention of neuropathic pain in rats using known PNDCs (FeTMPyP(5+) and MnTE-2-PyP(5+)). We also demonstrate the prevention of CIPN with our two new orally active PNDCs, SRI6 and SRI110. The improved chemical design of SRI6 and SRI110 also affords selectivity for PN over other reactive oxygen species (such as superoxide). Our findings identify PN as a critical determinant of CIPN, while providing the rationale toward development of superoxide-sparing and "PN-targeted" therapeutics. PMID:22553021

Doyle, Timothy; Chen, Zhoumou; Muscoli, Carolina; Bryant, Leesa; Esposito, Emanuela; Cuzzocrea, Salvatore; Dagostino, Concetta; Ryerse, Jan; Rausaria, Smita; Kamadulski, Andrew; Neumann, William L; Salvemini, Daniela

2012-05-01

65

Matrix metalloproteases: Underutilized targets for drug delivery  

PubMed Central

Pathophysiological molecules in the extracellular environment offer excellent targets that can be exploited for designing drug targeting systems. Matrix metalloproteases (MMPs) are a family of extracellular proteolytic enzymes that are characterized by their overexpression or overactivity in several pathologies. Over the last two decades, the MMP literature reveals heightened interest in the research involving MMP biology, pathology, and targeting. This review describes various strategies that have been designed to utilize MMPs for targeting therapeutic entities. Key factors that need to be considered in the successful design of such systems have been identified based on the analyses of these strategies. Development of targeted drug delivery using MMPs has been steadily pursued; however, drug delivery efforts using these targets need to be intensified and focused to realize the clinical application of the fast developing fundamental MMP research.

Vartak, Deepali G.; Gemeinhart, Richard A.

2013-01-01

66

Endocytic mechanisms for targeted drug delivery.  

PubMed

Advances in the delivery of targeted drug systems have evolved to enable highly regulated site specific localization to subcellular organelles. Targeting therapeutics to individual intracellular compartments has resulted in benefits to therapies associated with these unique organelles. Endocytosis, a mechanism common to all cells in the body, internalizes macromolecules and retains them in transport vesicles which traffic along the endolysosomal scaffold. An array of vesicular internalization mechanisms exist, therefore understanding the key players specific to each pathway has allowed researchers to bioengineer macromolecular complexes for highly specialized delivery. Membrane specific receptors most frequently enter the cell through endocytosis following the binding of a high affinity ligand. High affinity ligands interact with membrane receptors, internalize in membrane bound vesicles, and traffic through cells in different manners to allow for accumulation in early endosomal fractions or lysosomally associated fractions. Although most drug delivery complexes aim to avoid lysosomal degradation, more recent studies have shown the clinical utility in directed protein delivery to this environment for the enzymatic release of therapeutics. Targeting nanomedicine complexes to the endolysosomal pathway has serious potential for improving drug delivery for the treatment of lysosomal storage diseases, cancer, and Alzheimer's disease. Although several issues remain for receptor specific targeting, current work is investigating a synthetic receptor approach for high affinity binding of targeted macromolecules. PMID:17659804

Bareford, Lisa M; Swaan, Peter W

2007-06-28

67

Nanoparticles for intracellular-targeted drug delivery  

NASA Astrophysics Data System (ADS)

Nanoparticles (NPs) are very promising for the intracellular delivery of anticancer and immunomodulatory drugs, stem cell differentiation biomolecules and cell activity modulators. Although initial studies in the area of intracellular drug delivery have been performed in the delivery of DNA, there is an increasing interest in the use of other molecules to modulate cell activity. Herein, we review the latest advances in the intracellular-targeted delivery of short interference RNA, proteins and small molecules using NPs. In most cases, the drugs act at different cellular organelles and therefore the drug-containing NPs should be directed to precise locations within the cell. This will lead to the desired magnitude and duration of the drug effects. The spatial control in the intracellular delivery might open new avenues to modulate cell activity while avoiding side-effects.

Paulo, Cristiana S. O.; Pires das Neves, Ricardo; Ferreira, Lino S.

2011-12-01

68

Visualization and comparison of drug effects after local paclitaxel delivery with different catheter types  

Microsoft Academic Search

Background: The microtubule stabilizing compound paclitaxel has proved to have potent antiproliferative effects on smooth muscle cells\\u000a both in vitro and in vivo. It induces cellular modifications that result in reduced proliferation, migration and signal transduction\\u000a by shifting the cellular microtubule equilibrium towards assembly. We therefore reasoned that a visualization of the altered\\u000a cytoskeleton could enable an evaluation of the

Christian Herdeg; Martin Oberhoff; Andreas Baumbach; Andreas Blattner; Axel Küttner; Stephen Schröder; Karl K. Haase; Karl R. Karsch

1999-01-01

69

Nanoparticle mediated co-delivery of paclitaxel and a TLR-4 agonist results in tumor regression and enhanced immune response in the tumor microenvironment of a mouse model.  

PubMed

Inefficiency of cancer chemotherapy to improve life expectancy in majority of patients raises serious concern and warrants development of novel therapeutic strategies. Immunotherapy in combination with chemotherapy has shown promising outcomes in recent years. Herein, we report better tumor regression and enhancement of antitumor immune response at the tumor microenvironment by co-delivery of paclitaxel and a TLR4 agonist through a PLGA based nanoparticle preparation (TLNP). Particle characterization showed high encapsulation of both components and retention of their biological activities. In vivo tumor regression studies demonstrated clear benefit of TLNP over the paclitaxel. The mean tumor volume of the TLNP treated animals was found to be 40% less than that of the Paclitaxel treated animals. Flow cytometric analysis of tumor infiltrating immune cells indicated activation of antigen presenting cells and T-cells providing evidence of Th1 immune response. In vivo results are promising and could pave way for novel chemo-immunotherapeutic treatment modality. PMID:23376226

Roy, Aniruddha; Singh, Manu Smriti; Upadhyay, Pramod; Bhaskar, Sangeeta

2013-01-30

70

Implications of nanoscale based drug delivery systems in delivery and targeting tubulin binding agent, noscapine in cancer cells.  

PubMed

Noscapine, a tubulin binding anticancer agent undergoing Phase I/II clinical trials, inhibits tumor growth in nude mice bearing human xenografts of breast, lung, ovarian, brain, and prostrate origin. The analogues of noscapine like 9-bromonoscapine (EM011) are 5 to 10-fold more active than parent compound, noscapine. Noscapinoids inhibit the proliferation of cancer cells that are resistant to paclitaxel and epothilone. Noscapine also potentiated the anticancer activity of doxorubicin in a synergistic manner against triple negative breast cancer (TNBC). However, physicochemical and pharmacokinetic (ED50˜300-600 mg/kg bodyweight) limitations of noscapine present hurdle in development of commercial anticancer formulations. Therefore, objectives of the present review are to summarize the chemotherapeutic potential of noscapine and implications of nanoscale based drug delivery systems in enhancing the therapeutic efficacy of noscapine in cancer cells. We have constructed noscapine-enveloped gelatin nanoparticles, NPs and poly (ethylene glycol) grafted gelatin NPs as well as inclusion complex of noscapine in ?-cyclodextrin (?-CD) and evaluated their physicochemical characteristics. The Fe3O4 NPs were also used to incorporate noscapine in its polymeric nanomatrix system where molecular weight of the polymer governed the encapsulation efficiency of drug. The enhanced noscapine delivery using ?PAR-targeted optical-MR imaging trackable NPs offer a great potential for image directed targeted delivery of noscapine. Human Serum Albumin NPs (150-300 nm) as efficient noscapine drug delivery systems have also been developed for potential use in breast cancer. PMID:22571485

Chandra, Ramesh; Madan, Jitender; Singh, Prashant; Chandra, Ankush; Kumar, Pradeep; Tomar, Vartika; Dass, Sujata K

2012-12-01

71

Special delivery: targeted therapy with small RNAs.  

PubMed

Harnessing RNA interference using small RNA-based drugs has great potential to develop drugs designed to knock down expression of any disease-causing gene, thereby greatly expanding the universe of possible drug targets. However, delivering small RNAs into specific tissues and cells is still a hurdle. Here, we review recent progress in overcoming systemic, local and cellular barriers to RNA drug delivery, focusing on strategies for targeted uptake. PMID:21490679

Peer, D; Lieberman, J

2011-04-14

72

Special delivery: targeted therapy with small RNAs  

Microsoft Academic Search

Harnessing RNA interference using small RNA-based drugs has great potential to develop drugs designed to knock down expression of any disease-causing gene, thereby greatly expanding the universe of possible drug targets. However, delivering small RNAs into specific tissues and cells is still a hurdle. Here, we review recent progress in overcoming systemic, local and cellular barriers to RNA drug delivery,

D Peer; J Lieberman

2011-01-01

73

Tumor-host interaction in the optimization of paclitaxel-based combination therapies with vascular targeting compounds.  

PubMed

Targeting of the tumor stroma, including the tumor vasculature, represents a new frontier in the treatment of malignancy. Preclinical studies and clinical experiences have established that stroma-directed novel agents must be combined with conventional therapies in order to achieve relevant therapeutic efficacy. Here we review our preclinical experience on combinations of paclitaxel with a tyrosine kinase receptor inhibitor of angiogenesis (SU6668) and a vascular disrupting agent (VDA, ZD6126), and discuss the critical factors that determine the outcome of these treatments. We also analyze the relevance of the intrinsic sensitivity of the tumor to the drugs, as well as the possibility that the two combined agents synergistically affect the vasculature or independently target the host and the tumor compartments. Finally, we discuss the need to carefully optimize scheduling and sequencing, through the use of reliable end points, in order to avoid negative pharmacological interactions and to improve the antineoplastic efficacy of paclitaxel-based combination treatments. PMID:17896168

Giavazzi, Raffaella; Bani, Maria Rosa; Taraboletti, Giulia

2007-12-01

74

Polysaccharides for colon targeted drug delivery.  

PubMed

Colon targeted drug delivery has the potential to deliver bioactive agents for the treatment of a variety of colonic diseases and to deliver proteins and peptides to the colon for their systemic absorption. Various strategies, currently available to target the release of drugs to colon, include formation of prodrug, coating of pH-sensitive polymers, use of colon-specific biodegradable polymers, timed released systems, osmotic systems, and pressure controlled drug delivery systems. Among the different approaches to achieve targeted drug release to the colon, the use of polymers especially biodegradable by colonic bacteria holds great promise. Polysaccharidases are bacterial enzymes that are available in sufficient quantity to be exploited in colon targeting of drugs. Based on this approach, various polysaccharides have been investigated for colon-specific drug release. These polysaccharides include pectin, guar gum, amylose, inulin, dextran, chitosan, and chondroitin sulphate. This family of natural polymers has an appeal to drug delivery as it is comprised of polymers with a large number of derivatizable groups, a wide range of molecular weights, varying chemical compositions, and, for the most part, low toxicity and biodegradability yet high stability. The most favorable property of these materials is their approval as pharmaceutical excipients. PMID:15200012

Chourasia, M K; Jain, S K

75

The Formulation of Aptamer-Coated Paclitaxel-Polylactide Nanoconjugates and Their Targeting to Cancer Cells  

PubMed Central

Paclitaxel-polylactide (Ptxl-PLA) conjugate nanoparticles, termed as nanoconjugates (NCs), were prepared through Ptxl/(BDI)ZnN(TMS)2 (BDI = 2-((2,6-diisopropylphenyl)-amido)-4-((2,6-diisopropylphenyl)-imino)-2-pentene)-mediated controlled polymerization of lactide (LA) followed by nanoprecipitation. Nanoprecipitation of Ptxl-PLA resulted in sub-100 nm NCs with monomodal particle distributions and low polydispersities. The sizes of Ptxl-PLA NCs could be precisely controlled by using appropriate water-miscible solvents and by controlling the concentration of Ptxl-PLA during nanoprecipitation. Co-precipitation of a mixture of PLA-PEG-PLA (PLA = 14 kDa; PEG = 5kDa) and Ptxl-PLA in PBS resulted in NCs that could stay non-aggregated in PBS for an extended period of time. To develop solid formulations of NCs, we evaluated a series of lyoprotectants, aiming to identify candidates that could effectively reduce or eliminate NC aggregation during lyophilization. Albumin was found to be an excellent lyoprotectant for the preparation of NCs in solid form, allowing lyophilized NCs to be readily dispersed in PBS without noticeable aggregates. Aptamer-NCs bioconjugates were prepared and found to be able to effectively target prostate-specific membrane antigen in a cell-specific manner.

Tong, Rong; Yala, Linda; Fan, Timothy M.; Cheng, Jianjun

2011-01-01

76

The formulation of aptamer-coated paclitaxel-polylactide nanoconjugates and their targeting to cancer cells.  

PubMed

Paclitaxel-polylactide (Ptxl-PLA) conjugate nanoparticles, termed as nanoconjugates (NCs), were prepared through Ptxl/(BDI)ZnN(TMS)(2) (BDI = 2-((2,6-diisopropylphenyl)-amido)-4-((2,6-diisopropylphenyl)-imino)-2-pentene)-mediated controlled polymerization of lactide (LA) followed by nanoprecipitation. Nanoprecipitation of Ptxl-PLA resulted in sub-100 nm NCs with monomodal particle distributions and low polydispersities. The sizes of Ptxl-PLA NCs could be precisely controlled by using appropriate water-miscible solvents and by controlling the concentration of Ptxl-PLA during nanoprecipitation. Co-precipitation of a mixture of PLA-PEG-PLA (PLA = 14 kDa; PEG = 5 kDa) and Ptxl-PLA in PBS resulted in NCs that could stay non-aggregated in PBS for an extended period of time. To develop solid formulations of NCs, we evaluated a series of lyoprotectants, aiming to identify candidates that could effectively reduce or eliminate NC aggregation during lyophilization. Albumin was found to be an excellent lyoprotectant for the preparation of NCs in solid form, allowing lyophilized NCs to be readily dispersed in PBS without noticeable aggregates. Aptamer-NCs bioconjugates were prepared and found to be able to effectively target prostate-specific membrane antigen in a cell-specific manner. PMID:20122727

Tong, Rong; Yala, Linda; Fan, Timothy M; Cheng, Jianjun

2010-02-01

77

Bioresorbable polymersomes for targeted delivery of cisplatin.  

PubMed

Nontoxic bioresorbable polymersomes have been developed that efficiently and site-selectively tether targeting peptides under mild conditions with no toxic catalysts. The binding and release properties of these polymersomes have been evaluated when targeting DLD-1 human colon cancer cells overexpressing the ?(5)?(1) integrin. The delivery efficacy to these cells is markedly improved over commonly used RGD targeting peptides by use of an ?(5)?(1)-specific targeting peptide, PR_b. Release profiles in buffered solution from pH 7.4 to 4.5 were evaluated and compared to release after binding to cells, and enzymatic degradation was identified as a major cause of rapid payload release in the cell. Intracellular trafficking and release were imaged via confocal microscopy in live cells and colocalization with organelles was evaluated quantitatively over time. Finally, the anticancer drug cisplatin was encapsulated in the PR_b functionalized polymersomes and the presence of PR_b greatly improved delivery efficacy, with increased cisplatin-induced losses to targeted DLD-1 colon cancer cell viability. When delivered to CACO-2 model human epithelial cells expressing low levels of ?(5)?(1) integrin, low toxicity was maintained, suggesting that targeting was specific to ?(5)?(1) overexpressing cells. These results demonstrate that PR_b-functionalized bioresorbable polymersomes may be an attractive route to minimizing the dose-limiting side effects associated with existing approaches to cisplatin chemotherapy. PMID:23521104

Petersen, Matthew A; Hillmyer, Marc A; Kokkoli, Efrosini

2013-04-05

78

Liposomes Loaded with Paclitaxel and Modified with Novel Triphenylphosphonium-PEG-PE Conjugate Possess Low Toxicity, Target Mitochondria and Demonstrate Enhanced Antitumor Effects In Vitro and In Vivo  

PubMed Central

Previously, stearyl triphenylphosphonium (STPP)-modified liposomes (STPP-L) were reported to target mitochondria. To overcome a non-specific cytotoxicity of STPP-L, we synthesized a novel polyethylene glycol- phosphatidylethanolamine (PEG-PE) conjugate with the TPP group attached to the distal end of the PEG block (TPP-PEG-PE). This conjugate was incorporated into the liposomal lipid bilayer, and the modified liposomes were studied for their toxicity, mitochondrial targeting, and efficacy in delivering paclitaxel (PTX) to cancer cells in vitro and in vivo. These TPP-PEG-PE-modified liposomes (TPP-PEG-L), surface grafted with as high as 8 mole % of the conjugate, were less cytotoxic compared to STPP-L or PEGylated STPP-L. At the same time, TPP-PEG-L demonstrated efficient mitochondrial targeting in cancer cells as shown by confocal microscopy in co-localization experiments with stained mitochondria. PTX-loaded TPP-PEG-L demonstrated enhanced PTX-induced cytotoxicity and anti-tumor efficacy in cell culture and mouse experiments compared to PTX-loaded unmodified plain liposomes (PL). Thus, TPP-PEG-PE can serve as a targeting ligand to prepare non-toxic liposomes as mitochondria-targeted drug delivery systems (DDS).

Biswas, Swati; Dodwadkar, Namita S.; Deshpande, Pranali P.; Torchilin, Vladimir P.

2012-01-01

79

Integrin Targeted Delivery of Gene Therapeutics  

PubMed Central

Integrins have become key targets for molecular imaging and for selective delivery of anti-cancer agents. Here we review recent work concerning the targeted delivery of antisense and siRNA oligonucleotides via integrins. A variety of approaches have been used to link oligonucleotides to ligands capable of binding integrins with high specificity and affinity. This includes direct chemical conjugation, incorporating oligonucleotides into lipoplexes, and use of various polymeric nanocarriers including dendrimers. The ligand-oligonucleotide conjugate or complex associates selectively with the integrin, followed by internalization into endosomes and trafficking through subcellular compartments. Escape of antisense or siRNA from the endosome to the cytosol and nucleus may come about through endogenous trafficking mechanisms, or because of membrane disrupting capabilities built into the conjugate or complex. Thus a variety of useful strategies are available for using integrins to enhance the pharmacological efficacy of therapeutic oligonucleotides.

Juliano, Rudy L; Ming, Xin; Nakagawa, Osamu; Xu, Rongzuo; Yoo, Hoon

2011-01-01

80

Self-assembled silk sericin/poloxamer nanoparticles as nanocarriers of hydrophobic and hydrophilic drugs for targeted delivery  

NASA Astrophysics Data System (ADS)

In recent times self-assembled micellar nanoparticles have been successfully employed in tissue engineering for targeted drug delivery applications. In this review, silk sericin protein from non-mulberry Antheraea mylitta tropical tasar silk cocoons was blended with pluronic F-127 and F-87 in the presence of solvents to achieve self-assembled micellar nanostructures capable of carrying both hydrophilic (FITC-inulin) and hydrophobic (anticancer drug paclitaxel) drugs. The fabricated nanoparticles were subsequently characterized for their size distribution, drug loading capability, cellular uptake and cytotoxicity. Nanoparticle sizes ranged between 100 and 110 nm in diameter as confirmed by dynamic light scattering. Rapid uptake of these particles into cells was observed in in vitro cellular uptake studies using breast cancer MCF-7 cells. In vitro cytotoxicity assay using paclitaxel-loaded nanoparticles against breast cancer cells showed promising results comparable to free paclitaxel drugs. Drug-encapsulated nanoparticle-induced apoptosis in MCF-7 cells was confirmed by FACS and confocal microscopic studies using Annexin V staining. Up-regulation of pro-apoptotic protein Bax, down-regulation of anti-apoptotic protein Bcl-2 and cleavage of regulatory protein PARP through Western blot analysis suggested further drug-induced apoptosis in cells. This study projects silk sericin protein as an alternative natural biomaterial for fabrication of self-assembled nanoparticles in the presence of poloxamer for successful delivery of both hydrophobic and hydrophilic drugs to target sites.

Mandal, Biman B.; Kundu, S. C.

2009-09-01

81

Self-assembled silk sericin/poloxamer nanoparticles as nanocarriers of hydrophobic and hydrophilic drugs for targeted delivery.  

PubMed

In recent times self-assembled micellar nanoparticles have been successfully employed in tissue engineering for targeted drug delivery applications. In this review, silk sericin protein from non-mulberry Antheraea mylitta tropical tasar silk cocoons was blended with pluronic F-127 and F-87 in the presence of solvents to achieve self-assembled micellar nanostructures capable of carrying both hydrophilic (FITC-inulin) and hydrophobic (anticancer drug paclitaxel) drugs. The fabricated nanoparticles were subsequently characterized for their size distribution, drug loading capability, cellular uptake and cytotoxicity. Nanoparticle sizes ranged between 100 and 110 nm in diameter as confirmed by dynamic light scattering. Rapid uptake of these particles into cells was observed in in vitro cellular uptake studies using breast cancer MCF-7 cells. In vitro cytotoxicity assay using paclitaxel-loaded nanoparticles against breast cancer cells showed promising results comparable to free paclitaxel drugs. Drug-encapsulated nanoparticle-induced apoptosis in MCF-7 cells was confirmed by FACS and confocal microscopic studies using Annexin V staining. Up-regulation of pro-apoptotic protein Bax, down-regulation of anti-apoptotic protein Bcl-2 and cleavage of regulatory protein PARP through Western blot analysis suggested further drug-induced apoptosis in cells. This study projects silk sericin protein as an alternative natural biomaterial for fabrication of self-assembled nanoparticles in the presence of poloxamer for successful delivery of both hydrophobic and hydrophilic drugs to target sites. PMID:19671963

Mandal, Biman B; Kundu, S C

2009-08-11

82

AS1411 aptamer for targetable photosensitizer delivery  

Microsoft Academic Search

A specialized G-quadruplex DNA aptamer with nucleolin targeting ability, AS1411, has been studied for cancer therapy. In this study, we report a novel delivery strategy for chemo-photodynamic combined treatment using AS1411 aptamer conjugated with tetra-(N-methyl-4-pyridyl)-porphine by intercalation and outside binding. Our results show that the apt-TMP complex exhibited higher TMPyP4 accumulation in nucleolin over-expressing MCF-7 breast cancer cells than in

M. J. Shieh; Y. A. Shieh; P. S. Lai

2009-01-01

83

New Approaches to Targeted Drug Delivery  

NASA Astrophysics Data System (ADS)

For targeted drug delivery, one of the primary drawbacks lies with the inability to design a delivery system that can be loaded with a variety of drugs and biomolecules. Motivated by this challenge, we will present data showing 400 nm liposomes loaded via the novel method of lysenin pores. These pores are approximately 3 nm in diameter and can be closed with divalent and trivalent ions in addition to charged polymers. This new method allows for the controllable passage of large biomolecules such as DNA and protein without the inherent problems common to active and passive loading methods. We will show proof-of-concept results of this method using fluorescent calcein as a drug simulator. Furthermore, data demonstrating current attempts at loading DNA will also be presented.

Cooper, James; Oliver, William; Fologea, Daniel

2013-03-01

84

PEG-Derivatized Embelin as a Dual Functional Carrier for the Delivery of Paclitaxel  

PubMed Central

Embelin, identified primarily from the Embelia ribes plant, has been shown to be a natural small molecule inhibitor of X-linked inhibitor of apoptosis protein (XIAP). It is also a potent inhibitor of NF-?B activation, which makes it a potentially effective suppressor of tumor cell survival, proliferation, invasion, angiogenesis, and inflammation. However, embelin itself is insoluble in water, which makes it unsuitable for in vivo applications. In this work, we developed a novel micelle system through conjugating embelin to a hydrophilic polymer, polyethylene glycol 3,500 (PEG3.5K) through an aspartic acid bridge. The PEG3.5k-embelin2 (PEG3.5k-EB2) conjugate readily forms micelles in aqueous solutions with a CMC of 0.0205mg/mL. Furthermore, PEG3.5k-EB2 micelles effectively solubilize paclitaxel (PTX), a model hydrophobic drug used in this study. Both drug-free and drug-loaded micelles were small in sizes (20 ~ 30 nm) with low polydispersity indexes. In vitro cytotoxicity studies with several tumor cell lines showed that PEG3.5k-EB2 is comparable to embelin in antitumor activity and synergizes with PTX at much lower doses. Our results suggest that PEG-derivatized embelin may represent a novel and dual-functional carrier to facilitate the in vivo applications of poorly water-soluble anticancer drugs such as PTX.

Huang, Yixian; Lu, Jianqin; Gao, Xiang; Li, Jiang; Zhao, Wenchen; Sun, Ming; Stolz, Donna Beer; Venkataramanan, Raman; Rohan, Lisa Cencia; Li, Song

2012-01-01

85

Hyaluronic acid-based hydrogel for regional delivery of paclitaxel to intraperitoneal tumors  

PubMed Central

Intraperitoneal (IP) chemotherapy is an effective way of treating local and regional malignancies confined in the peritoneal cavity such as ovarian cancer. However, a persistent major challenge in IP chemotherapy is the need to provide effective drug concentrations in the peritoneal cavity for an extended period of time. We hypothesized that hyaluronic acid (HA)-based in-situ crosslinkable hydrogel would serve as a carrier of paclitaxel (PTX) particles to improve their IP retention and therapeutic effects. In-vitro gel degradation and release kinetics studies demonstrated that HA gels could entrap microparticulate PTX (>100 ?m) and release the drug over 10 days, gradually degraded by hyaluronidase, but had limited effect on retention of Taxol, a 14-nm micelle form of PTX. When administered IP to tumor-bearing nude mice, PTX was best retained in the peritoneal cavity as PTX-gel (microparticulate PTX entrapped in the HA gel), whereas Taxol-gel and other Taxol-based formulations left negligible amount of PTX in the cavity after 14 days. Despite the increase in IP retention of PTX, PTX-gel did not further decrease the tumor burdens than Taxol-based formulations, presumably due to the limited dissolution of PTX. This result indicates that spatial availability of a drug does not necessarily translate to the enhanced anti-tumor effect unless it is accompanied by the temporal availability.

Bajaj, Gaurav; Kim, Mi Ran; Mohammed, Sulma I.; Yeo, Yoon

2012-01-01

86

Paclitaxel loaded folic acid targeted nanoparticles of mixed lipid-shell and polymer-core: in vitro and in vivo evaluation.  

PubMed

A functional drug carrier comprised of folic acid modified lipid-shell and polymer-core nanoparticles (FLPNPs) including poly(D,L-lactide-co-glycolide) (PLGA) core, PEGylated octadecyl-quaternized lysine modified chitosan (PEG-OQLCS) as lipid-shell, folic acid as targeting ligand and cholesterol was prepared and evaluated for targeted delivery of paclitaxel (PTX). Confocal microscopy analysis confirmed the coating of the lipid-shell on the polymer-core. Physicochemical characterizations of FLPNPs, such as particle size, zeta potential, morphology, encapsulation efficiency, and in vitro PTX release, were also evaluated. The internalization efficiency and targeting ability of FLPNPs were demonstrated by flow cytometry and confocal microscopy. PTX loaded FLPNPs showed a significantly higher cytotoxicity than the commercial PTX formulation (Taxol®). The intravenous administration of PTX encapsulated FLPNPs led to tumor regression and improvement of animal survival in a murine model, compared with that observed with Taxol® and biodistribution study showed that PTX concentration in tumor for PTX encapsulated FLPNPs was higher than other PTX formulations. Our data indicate that PTX loaded FLPNPs are a promising nano-sized drug formulation for cancer therapy. PMID:22446630

Zhao, Peiqi; Wang, Hanjie; Yu, Man; Liao, Zhenyu; Wang, Xianhuo; Zhang, Fei; Ji, Wei; Wu, Bing; Han, Jinghua; Zhang, Haichang; Wang, Huaqing; Chang, Jin; Niu, Ruifang

2012-03-14

87

Targeted delivery of colloids by swimming bacteria.  

PubMed

The possibility of exploiting motile microorganisms as tiny propellers represents a fascinating strategy for the transport of colloidal cargoes. However, delivery on target sites usually requires external control fields to steer propellers and trigger cargo release. The need for a constant feedback mechanism prevents the design of compact devices where biopropellers could perform their tasks autonomously. Here we show that properly designed three-dimensional (3D) microstructures can define accumulation areas where bacteria spontaneously and efficiently store colloidal beads. The process is stochastic in nature and results from the rectifying action of an asymmetric energy landscape over the fluctuating forces arising from collisions with swimming bacteria. As a result, the concentration of colloids over target areas can be strongly increased or depleted according to the topography of the underlying structures. Besides the significance to technological applications, our experiments pose some important questions regarding the structure of stationary probability distributions in non-equilibrium systems. PMID:24100868

Koumakis, N; Lepore, A; Maggi, C; Di Leonardo, R

2013-01-01

88

Targeted delivery of colloids by swimming bacteria  

NASA Astrophysics Data System (ADS)

The possibility of exploiting motile microorganisms as tiny propellers represents a fascinating strategy for the transport of colloidal cargoes. However, delivery on target sites usually requires external control fields to steer propellers and trigger cargo release. The need for a constant feedback mechanism prevents the design of compact devices where biopropellers could perform their tasks autonomously. Here we show that properly designed three-dimensional (3D) microstructures can define accumulation areas where bacteria spontaneously and efficiently store colloidal beads. The process is stochastic in nature and results from the rectifying action of an asymmetric energy landscape over the fluctuating forces arising from collisions with swimming bacteria. As a result, the concentration of colloids over target areas can be strongly increased or depleted according to the topography of the underlying structures. Besides the significance to technological applications, our experiments pose some important questions regarding the structure of stationary probability distributions in non-equilibrium systems.

Koumakis, N.; Lepore, A.; Maggi, C.; di Leonardo, R.

2013-10-01

89

Targeted estrogen delivery reverses the metabolic syndrome.  

PubMed

We report the development of a new combinatorial approach that allows for peptide-mediated selective tissue targeting of nuclear hormone pharmacology while eliminating adverse effects in other tissues. Specifically, we report the development of a glucagon-like peptide-1 (GLP-1)-estrogen conjugate that has superior sex-independent efficacy over either of the individual hormones alone to correct obesity, hyperglycemia and dyslipidemia in mice. The therapeutic benefits are driven by pleiotropic dual hormone action to improve energy, glucose and lipid metabolism, as shown by loss-of-function models and genetic action profiling. Notably, the peptide-based targeting strategy also prevents hallmark side effects of estrogen in male and female mice, such as reproductive endocrine toxicity and oncogenicity. Collectively, selective activation of estrogen receptors in GLP-1-targeted tissues produces unprecedented efficacy to enhance the metabolic benefits of GLP-1 agonism. This example of targeting the metabolic syndrome represents the discovery of a new class of therapeutics that enables synergistic co-agonism through peptide-based selective delivery of small molecules. Although our observations with the GLP-1-estrogen conjugate justify translational studies for diabetes and obesity, the multitude of other possible combinations of peptides and small molecules may offer equal promise for other diseases. PMID:23142820

Finan, Brian; Yang, Bin; Ottaway, Nickki; Stemmer, Kerstin; Müller, Timo D; Yi, Chun-Xia; Habegger, Kirk; Schriever, Sonja C; García-Cáceres, Cristina; Kabra, Dhiraj G; Hembree, Jazzminn; Holland, Jenna; Raver, Christine; Seeley, Randy J; Hans, Wolfgang; Irmler, Martin; Beckers, Johannes; de Angelis, Martin Hrab?; Tiano, Joseph P; Mauvais-Jarvis, Franck; Perez-Tilve, Diego; Pfluger, Paul; Zhang, Lianshan; Gelfanov, Vasily; DiMarchi, Richard D; Tschöp, Matthias H

2012-11-11

90

PEG-PE-based micelles co-loaded with paclitaxel and cyclosporine A or loaded with paclitaxel and targeted by anticancer antibody overcome drug resistance in cancer cells.  

PubMed

The over-expression of the P-glycoprotein (P-gp) in cancer cells is one of the main reasons of the acquired Multidrug Resistance (MDR). Combined treatment of MDR cancer cells with P-gp inhibitors and chemotherapeutic agents could result in reversal of resistance in P-gp-expressing cells. In this study, paclitaxel (PTX) was co-encapsulated in actively targeted (anticancer mAb 2C5-modified) polymeric lipid-core PEG-PE-based micelles with Cyclosporine A (CycA), which is one of the most effective first generation P-gp inhibitors. Cell culture studies performed using MDCKII (parental and MDR1) cell lines to investigate the potential MDR reversal effect of the formulations. The average size of both empty and loaded PEG????-PE/Vitamin E mixed micelles was found between 10 and 25 nm. Zeta potentials of the formulations were found between -7 and -35 mV. The percentage of PTX in the micelles was found higher than 3% for both formulations and cumulative PTX release of about 70% was demonstrated. P-gp inhibition with CycA caused an increase in the cytotoxicity of PTX. Dual-loaded micelles demonstrated significantly higher cytotoxicity in the resistant MDCKII-MDR1 cells than micelles loaded with PTX alone. Micelle modification with mAb 2C5 results in the highest cytotoxicity against resistant cells, with or without P-gp modulator, probably because of better internalization bypassing the P-gp mechanism. Our results suggest that micelles delivering a combination of P-gp modulator and anticancer drug or micelles loaded with only PTX, but targeted with mAb 2C5 represent a promising approach to overcome drug resistance in cancer cells. PMID:22506922

Sarisozen, Can; Vural, Imran; Levchenko, Tatyana; Hincal, A Atilla; Torchilin, Vladimir P

2012-04-16

91

Multifunctional Magnetic Nanoparticles for Targeted Delivery  

PubMed Central

A major problem associated with therapy is the inability to deliver pharmaceuticals to a specific site of the body without causing nonspecific toxicity. Development of magnetic nanoparticles and techniques for their safe transport and concentration in specific sites in the body would constitute a powerful tool for gene/drug therapy in vivo. Furthermore, drug delivery in vitro could improve further if the drugs were modified with antibodies, proteins or ligands. For in vivo experiments, magnetic nanoparticles were conjugated with plasmid DNA expressing GFP and then coated with chitosan. These particles were injected into mice through tail vein and directed to heart and kidney by means of external magnets of 25 gauss or 2kA –kA/m. These particles were concentrated in the lungs, heart, and kidney of mice and the expression of GFP in these sites were monitored. The expression of GFP in specific locations was visualized by whole-body fluorescent imaging and the concentration of these particles in the designated body locations was confirmed by transmission electron microscopy. In another model system, we used atrial natriuretic peptide (ANP) and Carcino Embryonic Antigen (CEA) antibodies coupled to the chitosan coated magnetic nanoparticles to target cells in vitro. The present work demonstrates that a simple external magnetic field is all that is necessary to target a drug to a specific site inside the body without the need to functionalize the nanoparticles. However, the option to use magnetic targeting with external magnets on functionalized nanoparticles could prove as a more efficient means of drug delivery.

Kumar, Arun; Jena, Prasanna K.; Behera, Sumita; Lockey, Richard F.; Mohapatra, Subhra; Mohapatra, Shyam

2012-01-01

92

Design and characterization of chitosan nanoparticles as delivery systems for paclitaxel  

Microsoft Academic Search

The main objective of this research is to design a new extended release multiparticulate delivery system by incorporation into nanoparticles made of chitosan-polymethacrylic acid copolymers. As the first part of a continued research on conversion of chitosan to useful biopolymer-based materials, by grafting polymethacrylic acid (PMAA), free radical graft copolymerization was carried out at 70°C, with bis-acrylamide as a cross-linking

Mohammad Reza Saboktakin; Roya M. Tabatabaee; Abel Maharramov; Mohammad Ali Ramazanov

2010-01-01

93

Toward Intracellular Targeted Delivery of Cancer Therapeutics  

PubMed Central

A number of anti-cancer drugs have their targets localized to particular intracellular compartments. These drugs reach the targets mainly through diffusion, dependent on biophysical and biochemical forces that allow cell penetration. This means that both cancer cells and normal cells will be subjected to such diffusion; hence many of these drugs, like chemotherapeutics, are potentially toxic and the concentration achieved at the site of their action is often suboptimal. The same relates to radiation that indiscriminately affects normal and diseased cells. However, nature-designed systems enable compounds present in the extracellular environment to end up inside the cell and even travel to more specific intracellular compartments. For example, viruses and bacterial toxins can more or less specifically recognize eukaryotic cells, enter these cells, and direct some protein portions to designated intracellular areas. These phenomena have led to creative thinking, such as employing viruses or bacterial toxins for cargo delivery to cells and, more specifically, to cancer cells. Proteins can be genetically engineered in order to not only mimic what viruses and bacterial toxins can do, but also to add new functions, extending or changing the intracellular routes. It is possible to make conjugates or, more preferably, single-chain proteins that recognize cancer cells and deliver cargo inside the cells, even to the desired subcellular compartment. These findings offer new opportunities to deliver drugs/labels only to cancer cells and only to their site of action within the cells. The development of such dual-specificity vectors for targeting cancer cells is an attractive and potentially safer and more efficacious way of delivering drugs. We provide examples of this approach for delivering brain cancer therapeutics, using a specific biomarker on glioblastoma tumor cells.

Pandya, Hetal; Debinski, Waldemar

2013-01-01

94

Magnetizable implants for targeted drug delivery  

Microsoft Academic Search

The capability to deliver high effective dosages to specific sites in the human body has become the holy grail of drug delivery research. Drugs with proven effectiveness under in vitro investigation often reach a major roadblock under in vivo testing due to a lack of an effective delivery strategy. In addition, many clinical scenarios require delivery of agents that are

Zachary Graham Forbes

2005-01-01

95

The formulation of aptamer-coated paclitaxel–polylactide nanoconjugates and their targeting to cancer cells  

Microsoft Academic Search

Paclitaxel–polylactide (Ptxl–PLA) conjugate nanoparticles, termed as nanoconjugates (NCs), were prepared through Ptxl\\/(BDI)ZnN(TMS)2 (BDI = 2-((2,6-diisopropylphenyl)-amido)-4-((2,6-diisopropylphenyl)-imino)-2-pentene)-mediated controlled polymerization of lactide (LA) followed by nanoprecipitation. Nanoprecipitation of Ptxl–PLA resulted in sub-100 nm NCs with monomodal particle distributions and low polydispersities. The sizes of Ptxl–PLA NCs could be precisely controlled by using appropriate water-miscible solvents and by controlling the concentration of Ptxl–PLA during nanoprecipitation. Co-precipitation of a

Rong Tong; Linda Yala; Timothy M. Fan; Jianjun Cheng

2010-01-01

96

Supramolecular micellar nanoaggregates based on a novel chitosan/vitamin E succinate copolymer for paclitaxel selective delivery  

PubMed Central

Background Nowadays, many cytotoxic anticancer drugs exhibit low solubility and poor tumor selectivity, which means that the drug formulation is very important. For example, in the case of paclitaxel (PTX), Cremophor EL® (BASF, Ludwigshafen, Germany) needs to be used as a solubilizer in its clinical formulation (Taxol®, Bristol-Myers Squibb, New York, NY), although it can cause serious side effects. Nanomicellar systems are promising carriers to resolve the above problems, and the polymer chosen is the key element. Methods In this study, a novel amphiphilic chitosan/vitamin E succinate (CS-VES) copolymer was successfully synthesized for self-assembling polymeric micelles. Proton nuclear magnetic resonance spectroscopy and infrared were used to characterize the molecular structure of the copolymer. The PTX-loaded CS-VES polymeric micelles (PTX-micelles) were characterized by dynamic light scattering, transmission electron microscopy, X-ray diffraction, and differential scanning calorimetry. Results The critical micelle concentration of CS-VES was about 12.6 ?g/mL, with the degree of amino group substitution being 20.4%. PTX-micelles were prepared by a nanoprecipitation/dispersion technique without any surfactant being involved. PTX-micelles exhibited a drug loading as high as 21.37% and an encapsulation efficiency of 81.12%, with a particle size ranging from 326.3 to 380.8 nm and a zeta potential of +20 mV. In vitro release study showed a near zero-order sustained release, with 51.06%, 50.88%, and 44.35% of the PTX in the micelles being released up to 168 hours at three drug loadings of 7.52%, 14.09%, and 21.37%, respectively. The cellular uptake experiments, conducted by confocal laser scanning microscopy, showed an enhanced cellular uptake efficiency of the CS-VES micelles in MCF-7 cells compared with Taxol. The PTX-micelles exhibited a comparable but delayed cytotoxic effect compared with Taxol against MCF-7 cells, due to the sustained-release characteristics of the nanomicelles. More interestingly, blank nanomicelles based on CS-VES copolymer demonstrated significant cytotoxicity against MCF-7 cells. Conclusion The supramolecular micellar aggregates based on CS-VES copolymer is a promising nanocarrier and efficacy enhancer when used as an anticancer drug-delivery system.

Lian, He; Sun, Jin; Yu, Yan Ping; Liu, Yan Hua; Cao, Wen; Wang, Yong Jun; Sun, Ying Hua; Wang, Si Ling; He, Zhong Gui

2011-01-01

97

Colon targeted drug delivery systems--an overview.  

PubMed

In the last two decades colon targeted drug delivery has gained increased importance not just for the deliver drugs for the treatment of various colonic diseases but also for its potential for delivery of proteins and therapeutic peptides. In the past various traditional approaches used for colon targeted delivery like prodrugs, pH, time dependent, and microflora activated systems, have achieved limited success. For successful colon targeted drug delivery, the drug needs to be protected from absorption and/or the environment of the upper gastrointestinal tract and then be abruptly released into the colon. Hence continuous efforts have been made on designing colon targeted drug delivery systems with improved site specificity and versatile drug release kinetics to fulfill different therapeutic needs. In last couple of years few new systems have been developed for colon targeted drug delivery such as pressure dependent systems, CODES technology, microsponges, pectin and galactomannan coating, microbially triggered osmotic systems, lectins and neoglyconjugated etc. which are reported to have better in-vivo site specificity and design rationale than the earlier approaches. This review article gives an overview of various approaches for colonic targeted drug delivery with emphasis on newer systems, their merits and demerits, in vitro/ in-vivo evaluation and market status of such delivery systems. PMID:18673262

Kumar, P; Mishra, B

2008-07-01

98

miR-23a Targets Interferon Regulatory Factor 1 and Modulates Cellular Proliferation and Paclitaxel-Induced Apoptosis in Gastric Adenocarcinoma Cells  

PubMed Central

MicroRNAs are a class of non-coding RNAs that function as key regulators of gene expression at the post-transcriptional level. In our previous research, we found that miR-23a was significantly up-regulated in human gastric adenocarcinoma cells. In the current study, we demonstrate that miR-23a suppresses paclitaxel-induced apoptosis and promotes the cell proliferation and colony formation ability of gastric adenocarcinoma cells. We have identified tumor suppressor interferon regulator factor 1 (IRF1) as a direct target gene of miR-23a. We performed a fluorescent reporter assay to confirm that miR-23a bound to the IRF1 mRNA 3?UTR directly and specifically. The ectopic expression of IRF1 markedly promoted paclitaxel-induced apoptosis and inhibited cell viability and colony formation ability, whereas the knockdown of IRF1 had the opposite effects. The restoration of IRF1 expression counteracted the effects of miR-23a on the paclitaxel-induced apoptosis and cell proliferation of gastric adenocarcinoma cells. Quantitative real-time PCR showed that miR-23a is frequently up-regulated in gastric adenocarcinoma tissues, whereas IRF1 is down-regulated in cancer tissues. Altogether, these results indicate that miR-23a suppresses paclitaxel-induced apoptosis and promotes cell viability and the colony formation ability of gastric adenocarcinoma cells by targeting IRF1 at the post-transcriptional level.

Zhu, Li-hua; Liu, Min; Li, Xin; Tang, Hua

2013-01-01

99

Targeted Drug Delivery to the Eye Enabled by Microneedles  

Microsoft Academic Search

\\u000a Drug delivery targeted to specific tissues within the eye represents an important advance over conventional methods of topical\\u000a and injectable delivery that have poor specificity for particular ocular tissues requiring therapy. This level of intraocular\\u000a targeting can be achieved using microneedles, which are solid and ­hollow needles of micron dimensions. Microneedles can selectively\\u000a target intraocular tissues by delivering drug formulations

Samirkumar R. Patel; Henry F. Edelhauser; Mark R. Prausnitz

100

In vitro and in vivo anticancer activity of surface modified paclitaxel attached hydroxyapatite and titanium dioxide nanoparticles.  

PubMed

Targeted drug delivery using nanocrystalline materials delivers the drug at the diseased site. This increases the efficacy of the drug in killing the cancer cells. Surface modifications were done to target the drug to a particular receptor on the cell surface. This paper reports synthesis of hydroxyapatite and titanium dioxide nanoparticles and modification of their surface with polyethylene glycol (PEG) followed by folic acid (FA). Paclitaxel, an anticancer drug, is attached to functionalized hydroxyapatite and titanium dioxide nanoparticles. The pure and functionalised nanoparticles are characterised with XRD, TEM and UV spectroscopy. Anticancer analysis was carried out in DEN induced hepatocarcinoma animals. Biochemical, hematological and histopathological analysis show that the surface modified paclitaxel attached nanoparticles have an higher anticancer activity than the pure paclitaxel and surface modified nanoparticles without paclitaxel. This is due to the targeting of the drug to the folate receptor in the cancer cells. PMID:23615724

Venkatasubbu, G Devanand; Ramasamy, S; Reddy, G Pramod; Kumar, J

2013-08-01

101

Targeted Gene Delivery to Accomplish Gene Therapy for Breast Cancer.  

National Technical Information Service (NTIS)

We are developing methods to derive gene transfer vectors capable of accomplishing targeted gene delivery to metastatic breast cancer cells. In this regard, strategies have been explored to modify adenoviral vectors by altering their binding tropism. Gene...

D. T. Curiel

1998-01-01

102

Inhibition of smooth muscle cell proliferation after local drug delivery of the antimitotic drug paclitaxel using a porous balloon catheter  

Microsoft Academic Search

Percutaneous transluminal coronary angioplasty is an accepted treatment for coronary artery disease. The major limitation,\\u000a however, is the high incidence of restenosis which limits the long-term benefit of this intervention. Paclitaxel is a new\\u000a antiproliferative agent that has generated considerable scientific interest since it was introduced in clinical trials in\\u000a the early 1980s. Recent in vitro studies have shown that

Martin Oberhoff; Wolfgang Kunert; Christian Herdeg; Axel Küttner; Alexander Kranzhöfer; Barbara Horch; Andreas Baumbach; Karl R. Karsch

2001-01-01

103

Tumor Targeting Peptides for Cytotoxic Chemotherapy Delivery.  

National Technical Information Service (NTIS)

Tumors cannot grow without a blood supply. The distinct characteristics of tumor vasculature make it possible to design therapeutic agents that specifically target the tumor, but not normal blood vessels. Identifying tools for therapeutic tumor targeting ...

K. Porkka

2001-01-01

104

Arg-Gly-Asp (RGD) peptide conjugated poly(lactic acid)-poly(ethylene oxide) micelle for targeted drug delivery.  

PubMed

In this study, a new poly(lactic acid)-poly (ethylene oxide)-Arg-Gly-Asp (PLA-PEO-RGD) derivative was synthesized, and paclitaxel-loaded PLA-PEO-RGD micelles were prepared by this derivative. The solubility assay showed that micelles mixed with Pluronic F-68 as surfactant could increase the solubility of this hydrophobic paclitaxel in aqueous solution. The cell-binding assay showed that PLA-PEO-RGD micelle (IC(50) = 11.13 +/- 1.38 nmol/L) had about 3.6-fold higher integrin avidity than PLA-PEO-RGD conjugates (IC(50) = 40.33 +/- 3.12 nmol/L). The avidity of micelle was also higher than RGD4C peptide (IC(50) = 24.44 +/- 1.21 nmol/L). The in vitro drug release profile of drug-loaded PLA-PEO-RGD micelles exhibited initial burst release to 37% +/- 2% (w/w) during the first 12 h, and then the release rate became steady in a controlled release manner. Furthermore, treatment of the MDA-MB-435 breast cancer cell line with paclitaxel-loaded PLA-PEO-RGD micelles yielded cytotoxicities, with EC(50) values of approximately 30 mumol/L. The paclitaxel-loaded PLA-PEO-RGD micelles treated group showed the most dramatic tumor reduction in MDA-MB-435 tumor-bearing nude mice, and the final mean tumor load was 31 +/- 16 mm(3) (mean +/- SD; n = 8). (125)I-labeled micelles administration resulted in significant (p < 0.001) higher tumor uptake (2.68% +/- 0.14%, ID/g) of PLA-PEO-RGD micelles compared to PLA-PEO micelles (0.84% +/- 0.09%, ID/g) after 2.5 h postinjection. Biodistribution study showed the best blood clearance of PLA-PEO-RGD micelles after 4.5 h postinjection. The results of this study suggest that paclitaxel-loaded PLA-PEO-RGD micelles based on the specific recognition of alpha(V)beta(3) integrin represent a potential and powerful target delivery technology. PMID:17896765

Hu, Zhiyuan; Luo, Fang; Pan, Yifeng; Hou, Can; Ren, Lifeng; Chen, Jiji; Wang, Jiwei; Zhang, Yangde

2008-06-01

105

Pharmacokinetics and biodistribution of lonidamine\\/paclitaxel loaded, EGFR-targeted nanoparticles in an orthotopic animal model of multi-drug resistant breast cancer  

Microsoft Academic Search

The aim of this study was to assess the biodistribution and pharmacokinetics of epidermal growth factor receptor (EGFR)–targeted polymer-blend nanoparticles loaded with the anticancer drugs lonidamine and paclitaxel. Plasma, tumor, and tissue distribution profiles were quantified in an orthotopic animal model of multidrug-resistant breast cancer and were compared to treatment with nontargeted nanoparticles and to treatment with drug solution. A

Lara Milane; Zhen-feng Duan; Mansoor Amiji

2011-01-01

106

Echogenic Lipsomes for Targeted Drug Delivery  

Microsoft Academic Search

Echogenic immunoliposomes (ELIP) are under development to enable ultrasound-controlled drug delivery. Mechanistic studies in vitro have revealed that stable cavitation is correlated with enhanced recombinant tissue Plasminogen Activator (rt-PA) thrombolysis, yet strategies to optimize the occurrence of such bubble activity and avoid potential harmful bioeffects have yet to be identified. Stable cavitation is characterized by bubbles pulsating gently in response

Christy K. Holland; David D. McPherson

2009-01-01

107

[Research progress of polyamidoamine dendrimer in targeting drug delivery system].  

PubMed

Targeting drug delivery system (TDDS) is one of the most concerned research fields in cancer treatment because it can bind selectively and react with the target diseased sites at the cellular or sub-cellular level, making distribution and release of drugs in a controlled manner, thus enhance therapeutic effects and reduce toxic and side-effects on normal cells. Polyamidoamine dendrimer (PAMAMD) is a kind of newly developed polymer in nanometer degree. Hyper-branched, monodispersity, three-dimensional structure and host-guest entrapment ability make it used as drug carrier, gene delivery system and imaging agent. Various targeting ligands, which have high affinity to specific organs, tissues or cells in human body, can be linked to surface functional groups of PAMAMD. And drugs and theoretical gene are carried by encapsulation or chemical conjugation. Finally, PAMAMD targeting drug delivery system can carry drugs and theoretical gene to diseased sites and then release them for targeted therapy. The PAMAMD-based conjugates have small size, ligh permeability and retention effect (EPR), low toxicity and so on. The research progress of PAMAMD modified by different ligands in targeting drug delivery system is reviewed, and research direction of the PAMAMD targeting delivery system in the future is also suggested. PMID:21800534

Ding, Rong-min; He, Hua; Li, Juan

2011-05-01

108

Nanocarriers targeting dendritic cells for pulmonary vaccine delivery.  

PubMed

Pulmonary vaccine delivery has gained significant attention as an alternate route for vaccination without the use of needles. Immunization through the pulmonary route induces both mucosal and systemic immunity, and the delivery of antigens in a dry powder state can overcome some challenges such as cold-chain and availability of medical personnel compared to traditional liquid-based vaccines. Antigens formulated as nanoparticles (NPs) reach the respiratory airways of the lungs providing greater chance of uptake by relevant immune cells. In addition, effective targeting of antigens to the most 'professional' antigen presenting cells (APCs), the dendritic cells (DCs) yields an enhanced immune response and the use of an adjuvant further augments the generated immune response thus requiring less antigen/dosage to achieve vaccination. This review discusses the pulmonary delivery of vaccines, methods of preparing NPs for antigen delivery and targeting, the importance of targeting DCs and different techniques involved in formulating dry powders suitable for inhalation. PMID:23054093

Kunda, Nitesh K; Somavarapu, Satyanarayana; Gordon, Stephen B; Hutcheon, Gillian A; Saleem, Imran Y

2012-10-09

109

Metronomic Activity of CD44-Targeted Hyaluronic Acid-Paclitaxel in Ovarian Carcinoma  

PubMed Central

Purpose Most primary human ovarian tumors and peritoneal implants, as well as tumor vascular endothelial cells, express the CD44 family of cell surface proteoglycans, the natural ligand for which is hyaluronic acid (HA). Metronomic (MET) dosing, the frequent administration of chemotherapeutics at substantially lower than maximum tolerated doses (MTD), has been shown to result in reduced normal tissue toxicity and to minimize “off-treatment” exposure resulting in an improved therapeutic ratio. Experimental Design We tested the hypothesis that HA conjugates of paclitaxel (TXL; HA-TXL) would exert strong anti-tumor effects with MET dosing and induce anti-angiogenic effects superior to those achieved with MTD administration or with free TXL. Female nude mice bearing SKOV3ip1 or HeyA8 ovarian cancer cells were treated intraperitoneally (ip) with MET HA-TXL regimens (or MTD administration to determine therapeutic and biological effects. Results All MET HA-TXL-treated mice and the MTD group revealed significantly reduced tumor weights and nodules compared to controls (all p values < 0.05) in the chemotherapy-sensitive models. However, the MTD HA-TXL-treated mice showed significant weight loss compared to control mice, whereas body weights were not affected in the MET groups in HeyA8-MDR model, reflecting reduced toxicity. In the taxane-resistant HeyA8-MDR model, significant reduction in tumor weight and nodule counts was noted in the MET groups, whereas the response of the MTD group did not achieve significance. While both MTD and MET regimens reduced proliferation (Ki-67) and increased apoptosis (TUNEL), only MET treatment resulted in significant reductions in angiogenesis (CD31, microvessel density). Moreover, MET treatment resulted in substantial increases in thrombospondin-1 (Tsp-1), an inhibitor of angiogenesis. Conclusions This study demonstrated that MET HA-TXL regimens have substantial antitumor activity in ovarian carcinoma, likely via a predominant anti-angiogenic mechanism.

Lee, Sun Joo; Ghosh, Sukhen C.; Han, Hee Dong; Stone, Rebecca L.; Bottsford-Miller, Justin; Shen, De Yue; Auzenne, Edmond J.; Lopez-Araujo, Alejandro; Lu, Chunhua; Nishimura, Masato; Pecot, Chad V.; Zand, Behrouz; Thanapprapasr, Duangmani; Jennings, Nicholas B; Kang, Yu; Huang, Jie; Hu, Wei; Klostergaard, Jim; Sood, Anil K.

2013-01-01

110

ECHOGENIC LIPSOMES FOR TARGETED DRUG DELIVERY.  

PubMed

Echogenic immunoliposomes (ELIP) are under development to enable ultrasound-controlled drug delivery. Mechanistic studies in vitro have revealed that stable cavitation is correlated with enhanced recombinant tissue Plasminogen Activator (rt-PA) thrombolysis, yet strategies to optimize the occurrence of such bubble activity and avoid potential harmful bioeffects have yet to be identified. Stable cavitation is characterized by bubbles pulsating gently in response to the time-varying acoustic pressure in an ultrasound field. A review of in vitro sonothrombolysis studies utilizing commercial US contrast agent or echogenic liposomes loaded with rt-PA to nucleate stable cavitation will be presented. Strategies for the development of ultrasound-enhanced thrombolysis and drug delivery will be discussed. PMID:20383294

Holland, Christy K; McPherson, David D

2009-06-28

111

Targeted Cellular Drug Delivery using Tailored Dendritic Nanostructures  

Microsoft Academic Search

Dendrimers and hyperbranched polymers possess highly branched architectures, with a large number of controllable, tailorble, `peripheral' functionalities. Since the surface chemistry of these materials can be modified with relative ease, these materials have tremendous potential in targeted drug and gene delivery. The large number of end groups can also be tailored to create special affinity to targeted cells, and can

Rangaramanujam Kannan; Parag Kolhe; Sujatha Kannan; Mary Lieh-Lai

2002-01-01

112

Subcellular targeting strategies for drug design and delivery  

Microsoft Academic Search

Many drug targets are localized to particular subcellular compartments, yet current drug design strategies are focused on bioavailability and tissue targeting and rarely address drug delivery to specific intracellular compartments. Insights into how the cell traffics its constituents to these different cellular locations could improve drug design. In this Review, we explore the fundamentals of membrane trafficking and subcellular organization,

Lawrence Rajendran; Hans-Joachim Knölker; Kai Simons

2010-01-01

113

Target delivery system for high repetition rate lasers  

Microsoft Academic Search

We present early prototype of a high repetition target delivery system, designed for nominal operation rate at 1 Hz but with possibility of running at up to 10 Hz. The system is primarily intended to deliver complex solid-state targets, such as composite foils or structured shapes, in vacuum environment into the focus of a high-repetition laser. The system in its

J. Polan; T. Havlicek; B. Rus

2007-01-01

114

Receptor-targeted nanocarriers for therapeutic delivery to cancer  

PubMed Central

Efficient and site-specific delivery of therapeutic drugs is a critical challenge in clinical treatment of cancer. Nano-sized carriers such as liposomes, micelles, and polymeric nanoparticles have been investigated for improving bioavailability and pharmacokinetic properties of therapeutics via various mechanisms, for example, the enhanced permeability and retention (EPR) effect. Further improvement can potentially be achieved by conjugation of targeting ligands onto nanocarriers to achieve selective delivery to the tumour cell or the tumour vasculature. Indeed, receptor-targeted nanocarrier delivery has been shown to improve therapeutic responses both in vitro and in vivo. A variety of ligands have been investigated including folate, transferrin, antibodies, peptides and aptamers. Multiple functionalities can be incorporated into the design of nanoparticles, e.g., to enable imaging and triggered intracellular drug release. In this review, we mainly focus on recent advances on the development of targeted nanocarriers and will introduce novel concepts such as multi-targeting and multi-functional nanoparticles.

YU, BO; TAI, HENG CHIAT; XUE, WEIMING; LEE, L. JAMES; LEE, ROBERT J.

2013-01-01

115

Targeted Therapeutics and Nanodevices for Vascular Drug Delivery: Quo Vadis?  

PubMed Central

Summary This issue of the journal is dedicated to targeted delivery of therapeutics in the vasculature, an approach that holds promise to optimize treatment of diverse pathological conditions ranging from ischemia and tumor growth to metabolic and genetic diseases. From the standpoint of drug delivery, circulation system represents the natural route to the targets, whereas its components (blood and vascular cells) represent targets, carriers or barriers for drug delivery. Diverse nanodevices and targeted therapeutic agents that are designed and tested in animal and early clinical studies to achieve optimal and precise spatiotemporal control of the pharmacokinetics, destination, metabolism and effect of pharmacological agents will be discussed in this introductory essay and subsequent critical reviews in this series.

Muzykantov, Vladimir R.

2012-01-01

116

Synthesis and Preliminary Biological Evaluation of High-drug Load Paclitaxel-Antibody Conjugates for Tumor-targeted Chemotherapy1  

PubMed Central

The goal of this study was to design paclitaxel (PTX)-monoclonal antibody (MAb) prodrug conjugates (PTXMAbs) with the ability to deliver therapeutically significant doses of the drug to the tumor while avoiding the previously observed solubility limitations of conjugates with PTX : MAb molar ratios of >3. New PTX conjugates were synthesized using the discrete poly(ethylene glycol) (dPEG) as linkers. These compounds, PTX-L-Lys[(dPEG12)3-dPEG4]-dPEG6-NHS (9a and 9b, for L=GL or SX, respectively), were then conjugated to the anti-epidermal growth factor receptor MAb, C225 at increasing PTX : C225 ratios, producing completely soluble conjugates. Unlike the earlier PTXMAbs, buffered solutions of these conjugates remained homogeneous for extended periods of time. Fluorescence-activated cell sorting (FACS) analysis indicated preserved immunogenicity of the conjugates at all 4 substitution ratios, while cytotoxicity studies in MDA-MB-468 breast cancer cells indicated preservation of drug cytotoxicity. These conjugates may have potential in the development of high-drug-load tumor-targeting taxanes.

Quiles, Sherly; Raisch, Kevin P.; Sanford, Leisa L.; Bonner, James A.; Safavy, Ahmad

2009-01-01

117

A new probe for targeting drug delivery system.  

PubMed

Recently, TDDS (Targeting drug delivery system) plays an important role in enhancing the bioavailability and targeting of anti-tumor drugs. How to transport drugs quickly and precisely to their target sites of action has not been solved fundamentally. A large number of researches have identified artemisinin and its analogs have the merit of precisely targeting to cancer cell, and low side effects to healthy tissue. Thus, if these compounds could be attached to established anti-tumor drugs with probe, a novel targeting anti-tumor drugs will be put into practice in the future. The novel drugs delivery system will be a powerful weapon against cancer disease for their unique targeting. PMID:18829175

Yu, Zhengwen; Wang, Bochu; Sui, Jing; Feng, Yingzhu; Zheng, Chao

2008-09-30

118

Targeted Delivery to Legumain-Expressing Cells.  

National Technical Information Service (NTIS)

The present invention relates to new agents and methods useful for preventing, treating and diagnosing diseases such as cancer. For example, the invention relates to prodrug agents useful for targeting and delivering cytotoxic drugs to cancerous cells.

C. Liu T. S. Edgington

2005-01-01

119

Functionalized Nanosystems for Targeted Mitochondrial Delivery  

PubMed Central

Mitochondrial dysfunction including oxidative stress and DNA mutations underlies the pathology of various diseases including Alzheimer’s disease and diabetes, necessitating the development of mitochondria targeted therapeutic agents. Nanotechnology offers unique tools and materials to target therapeutic agents to mitochondria. As discussed in this paper, a variety of functionalized nanosystems including polymeric and metallic nanoparticles as well as liposomes are more effective than plain drug and non-functionalized nanosystems in delivering therapeutic agents to mitochondria. Although the field is in its infancy, studies to date suggest the superior therapeutic activity of functionalized nanosystems for treating mitochondrial defects.

Durazo, Shelley A.; Kompella, Uday B.

2011-01-01

120

Functionalized nanosystems for targeted mitochondrial delivery.  

PubMed

Mitochondrial dysfunction including oxidative stress and DNA mutations underlies the pathology of various diseases including Alzheimer's disease and diabetes, necessitating the development of mitochondria targeted therapeutic agents. Nanotechnology offers unique tools and materials to target therapeutic agents to mitochondria. As discussed in this paper, a variety of functionalized nanosystems including polymeric and metallic nanoparticles as well as liposomes are more effective than plain drug and non-functionalized nanosystems in delivering therapeutic agents to mitochondria. Although the field is in its infancy, studies to date suggest the superior therapeutic activity of functionalized nanosystems for treating mitochondrial defects. PMID:22138492

Durazo, Shelley A; Kompella, Uday B

2011-11-23

121

Endogenous lectins as targets for drug delivery  

Microsoft Academic Search

To minimize side effects of drugs it would be ideal to target them exclusively to those cell types which require treatment. As a means to this end prototypical cellular recognition systems pique our interest to devise biomimetic strategies. Since oligosaccharides of glycoconjugates outmatch other information-carrying biomolecules (proteins, nucleic acids) in theoretical storage capacity by far, work on the sugar code

N. Yamazaki; S. Kojima; N. V. Bovin; S. André; S. Gabius; H.-J. Gabius

2000-01-01

122

Adenoviral vectors: Systemic delivery and tumor targeting  

Microsoft Academic Search

The development of a targeted adenoviral vector, which can be delivered systemically, is one of the major challenges facing cancer gene therapy. The virus is readily cleared from the bloodstream, can be neutralised by pre-existing antibodies, and has a permissive cellular tropism. Clinical studies using the ONYX virus have shown limited efficacy, but there are several hurdles to overcome to

Nicola K Green; Leonard W Seymour

2002-01-01

123

Delivery to Intracellular Targets by Nanosized Particles  

Microsoft Academic Search

\\u000a Nanosized drug carrier systems, including liposomes and nanoparticles, have the potential of delivering their contents to\\u000a the interior of cells. However, engineering of the particle size and surface properties is necessary to achieve targeting\\u000a to particular cell types. Conventional particles with hydrophobic surfaces are rapidly engulfed by phagocytic cells. Modification\\u000a of the surface with hydrophilic polymers yields so-called “Stealth” particles

Gillian Barratt

124

Colon Targeted Delivery Systems: Review of Polysaccharides for Encapsulation and Delivery  

Microsoft Academic Search

Colon-targeted delivery of bioactives has recently gained importance in addressing specific needs in the therapy of colon-based diseases. Many approaches have been attempted for the development of colon-specific delivery systems, with not much success in the past. Recent research into the utilization of the metabolic activity and the colonic microenvironment in the lower gastrointestinal tract has attained great value in

Shantha L. Kosaraju

2005-01-01

125

Targeted delivery with peptidomimetic conjugated self-assembled nanoparticles.  

PubMed

Peptides produce specific nanostructures, making them useful for targeting in biological systems but they have low bioavailability, potential immunogenicity and poor metabolic stability. Peptidomimetic self-assembled NPs can possess biological recognition motifs as well as providing desired engineering properties. Inorganic NPs, coated with self-assembled macromers for stability and anti-fouling, and conjugated with target-specific ligands, are advancing imaging from the anatomy-based level to the molecular level. Ligand conjugated NPs are attractive for cell-selective tumor drug delivery, since this process has high transport capacity as well as ligand dependent cell specificity. Peptidomimetic NPs can provide stronger interaction with surface receptors on tumor cells, resulting in higher uptake and reduced drug resistance. Self-assembled NPs conjugated with peptidomimetic antigens are ideal for sustained presentation of vaccine antigens to dendritic cells and subsequent activation of T cell mediated adaptive immune response. Self-assembled NPs are a viable alternative to encapsulation for sustained delivery of proteins in tissue engineering. Cell penetrating peptides conjugated to NPs are used as intracellular delivery vectors for gene expression and as transfection agents for plasmid delivery. In this work, synthesis, characterization, properties, immunogenicity, and medical applications of peptidomimetic NPs in imaging, tumor delivery, vaccination, tissue engineering, and intracellular delivery are reviewed. PMID:19085091

Jabbari, Esmaiel

2008-12-17

126

Targeted Delivery of Radioprotective Agents to Mitochondria  

PubMed Central

Adverse effects of ionizing radiation are mediated through reactive oxygen and nitrogen species. Mitochondria are the principal source of these species in the cell and play an important role in irradiation-induced apoptosis. The use of free radical scavengers and nitric oxide synthase inhibitors has proven to protect normal tissues and, in some cases, to sensitize tumor tissues to radiation damage. Dual molecules that combine radical-scavenging and NOS-inhibitory functions may be particularly effective. Drugging strategies that target mitochondria can enhance the effectiveness of such agents, in comparison to systemic administration, and circumvent side effects.

Zabbarova, Irina; Kanai, Anthony

2010-01-01

127

Strategies on the nuclear-targeted delivery of genes.  

PubMed

Abstract To improve the nuclear-targeted delivery of non-viral vectors, extensive effort has been carried out on the development of smart vectors which could overcome multiple barriers. The nuclear envelope presents a major barrier to transgene delivery. Viruses are capable of crossing the nuclear envelope to efficiently deliver their genome into the nucleus through the specialized protein components. However, non-viral vectors are preferred over viral ones because of the safety concerns associated with the latter. Non-viral delivery systems have been designed to include various types of components to enable nuclear translocation at the periphery of the nucleus. This review summarizes the progress of research regarding nuclear transport mechanisms. "Smart" non-viral vectors that have been modified by peptides and other small molecules are able to facilitate the nuclear translocation and enhance the efficacy of gene expression. The resulting technology may also enhance delivery of other macromolecules to the nucleus. PMID:23964565

Yao, Jing; Fan, Ying; Li, Yuanke; Huang, Leaf

2013-08-22

128

Liposomes surface conjugated with human hemoglobin target delivery to macrophages  

PubMed Central

Current strategies to deliver therapeutic molecules to specific cell and tissue types rely on conjugation of antibodies and other targeting ligands directly to the therapeutic molecule itself or its carrier. This work describes a novel strategy to deliver therapeutic molecules into macrophages that takes advantage of the native hemoglobin (Hb) scavenging activity of plasma haptoglobin (Hp) and the subsequent uptake of the Hb-Hp complex into macrophages via CD163 receptor mediated endocytosis. The drug delivery system described in this work consists of hemoglobin decorated liposomes that can encapsulate any therapeutic molecule of interest, in this case the model fluorescent dye calcein was used in this study. The results of this study clearly demonstrate that this delivery system is specific towards macrophages and demonstrates the feasibility of using this approach in targeted drug delivery.

Zhang, Ning; Palmer, Andre F.

2012-01-01

129

Bacteria-responsive multifunctional nanogel for targeted antibiotic delivery.  

PubMed

Bacteria-Responsive Multifunctional Nanogel: We developed a bacteria-responsive multifunctional nanogel for targeted antibiotic delivery, in which bacterial enzymes are utilized to trigger antibiotic release by degrading the polyphosphoester core. The mannosylated nanogel preferentially delivers drugs to macrophages and leads to drug accumulation at bacterial infection sites through macrophage transport. This nanogel provides macrophage targeting and lesion site-activatable drug release properties, which enhances bacterial growth inhibition. PMID:22961974

Xiong, Meng-Hua; Li, Ya-Juan; Bao, Yan; Yang, Xian-Zhu; Hu, Bing; Wang, Jun

2012-09-10

130

Adhesion Dynamics of Functional Nanoparticles for Targeted Drug Delivery  

Microsoft Academic Search

Adhesion of micro and nanoparticles onto cardiovascular walls is a critical process in applications such as targeted drug delivery, biomedical imaging, and cancer treatment. This paper intends to develop an understanding of the dynamic interaction between particle and vessel wall through computational modeling. The ligand-receptor binding dynamics is coupled with Immersed Finite Element Method to study the adhesion process of

Yaling Liu; Samar Shah; Wenchuang Hu; Jinming Gao

131

Development of colon targeted drug delivery systems for mebendazole  

Microsoft Academic Search

The objective of the present study is to develop colon targeted drug delivery systems for mebendazole using guar gum as a carrier. Matrix tablets containing various proportions of guar gum were prepared by wet granulation technique using starch paste as a binder. The tablets were evaluated for drug content uniformity, and were subjected to in vitro drug release studies. The

Y. S. R Krishnaiah; P Veer Raju; B Dinesh Kumar; P Bhaskar; V Satyanarayana

2001-01-01

132

Targeted drug delivery and enhanced intracellular release using functionalized liposomes  

Microsoft Academic Search

The ability to target cancer cells using an appropriate drug delivery system can significantly reduce the associated side effects from cancer therapies and can help in improving the overall quality of life, post cancer survival. Integrin alpha5beta1 is expressed on several types of cancer cells, including colon cancer and plays an important role in tumor growth and metastasis. Thus, the

Ashish Garg

2009-01-01

133

Targeting the Delivery of Army Advertisements on Television.  

National Technical Information Service (NTIS)

The U.S. Army uses advertisements to affect the knowledge, attitudes, and behavioral intentions of youth to effectively recruit manpower. Both the message content and the delivery of the message are targeted to recruit soldiers who are most likely to prov...

T. Ellig

1988-01-01

134

The preparation and characterization of anti-VEGFR2 conjugated, paclitaxel-loaded PLLA or PLGA microspheres for the systemic targeting of human prostate tumors  

Microsoft Academic Search

Purpose  The objective of this study was to manufacture paclitaxel (PTX) loaded polymeric microspheres, that were surface conjugated\\u000a with antibodies to vascular endothelial growth factor receptor 2 (anti-VEGFR2), for systemic targeting to angiogenic sites\\u000a in prostate tumors.\\u000a \\u000a \\u000a \\u000a Methods  Microspheres were manufactured in the 1–3 ?m size range from poly (l-lactic acid) (PLLA) or poly (lactide-co-glycolide) (PLGA)\\u000a by a modified solvent evaporation method using

Jianjun Lu; John K. Jackson; Martin E. Gleave; Helen M. Burt

2008-01-01

135

Ex vivo investigation of magnetically targeted drug delivery system  

NASA Astrophysics Data System (ADS)

In conventional systemic drug delivery the drug is administered by intravenous injection; it then travels to the heart from where it is pumped to all regions of the body. When the drug is aimed at a small target region, this method is extremely inefficient and leads to require much larger doses than those being necessary. In order to overcome this problem a number of targeted drug delivery methods are developed. One of these, magnetically targeted drug delivery system (MT-DDS) will be a promising way, which involves binding a drug to small biocompatible magnetic particles, injecting these into the blood stream and using a high gradient magnetic field to pull them out of suspension in the target region. In the present paper, we describe an ex vivo experimental work. It is also reported that navigation and accumulation test of the magnetic particles in the Y-shaped glass tube was performed in order to examine the threshold of the magnetic force for accumulation. It is found that accumulation of the magnetic particles was succeeded in the blood vessel when a permanent magnet was placed at the vicinity of the blood vessel. This result indicates the feasibility of the magnetically drug targeting in the blood vessel.

Yoshida, Y.; Fukui, S.; Fujimoto, S.; Mishima, F.; Takeda, S.; Izumi, Y.; Ohtani, S.; Fujitani, Y.; Nishijima, S.

2007-03-01

136

Colon targeting: an emerging frontier for oral insulin delivery.  

PubMed

Subcutaneous administration of insulin is associated with several limitations such as discomfort, local pain, irritation, infections, immune reactions and lipoatrophy as well as lipohypertrophy manifestations at the injection site. To overcome these drawbacks, enormous research is currently going on worldwide for designing of an alternative noninvasive route of administration. Pulmonary and oral route seem to be the most promising ones, with respect to the market value. However, after the letdown by pulmonary delivery of insulin, oral colon targeted delivery of insulin has gained tremendous interest among researchers. Although bioavailability remains a challenge for oral colon specific delivery of insulin, the employment of protease inhibitors, permeation enhancers and polymeric delivery systems have proved to be advantageous to overcome the said problem. This Editorial article is not intended to offer a comprehensive review on drug delivery, but shall familiarize the readers with the strategies employed for attaining non-erratic bioavailability of insulin, and to highlight some of the formulation technologies that have been developed for attaining oral colon-specific delivery of insulin. PMID:23521062

Patel, Mayur Mahendrakumar

2013-03-25

137

Lipid carrier systems for targeted drug and gene delivery.  

PubMed

For effective chemotherapy, it is necessary to deliver therapeutic agents selectively to their target sites, since most drugs are associated with both beneficial effects and side effects. The use of lipid dispersion carrier systems, such as lipid emulsions and liposomes, as carriers of lipophilic drugs has attracted particular interest. A drug delivery system can be defined as a methodology for manipulating drug distribution in the body. Since drug distribution depends on the carrier, administration route, particle size of the carrier, lipid composition of the carrier, electric charge of the carrier and ligand density of the targeting carrier, these factors must be optimized. Recently, the lipid carrier system has also been applied to gene delivery systems for gene therapy. However, in both drug and gene medicine cases, a lack of cell-selectivity limits the wide application of this kind of drug and/or gene therapy. Therefore, lipid carrier systems for targeted drug and gene delivery must be developed for the rational therapy. In this review, we shall focus on the progress of research into lipid carrier systems for drug and gene delivery following systemic or local injection. PMID:16079512

Hashida, Mitsuru; Kawakami, Shigeru; Yamashita, Fumiyoshi

2005-08-01

138

Pharmacytes: an ideal vehicle for targeted drug delivery.  

PubMed

An ideal nanotechnology-based drug delivery system is a pharmacyte--a self-powered, computer-controlled medical nanorobot system capable of digitally precise transport, timing, and targeted delivery of pharmaceutical agents to specific cellular and intracellular destinations within the human body. Pharmacytes may be constructed using future molecular manufacturing technologies such as diamond mechanosynthesis which are currently being investigated theoretically using quantum ab initio and density-functional computational methods. Pharmacytes will have many applications in nanomedicine such as initiation of apoptosis in cancer cells and direct control of cell signaling processes. PMID:17048481

Freitas, Robert A

139

Bispecific digoxigenin-binding antibodies for targeted payload delivery  

PubMed Central

Bispecific antibodies that bind cell-surface targets as well as digoxigenin (Dig) were generated for targeted payload delivery. Targeting moieties are IgGs that bind the tumor antigens Her2, IGF1R, CD22, or LeY. A Dig-binding single-chain Fv was attached in disulfide-stabilized form to C termini of CH3 domains of targeting antibodies. Bispecific molecules were expressed in mammalian cells and purified in the same manner as unmodified IgGs. They are stable without aggregation propensity and retain binding specificity/affinity to cell-surface antigens and Dig. Digoxigeninylated payloads were generated that retain full functionality and can be complexed to bispecific antibodies in a defined 2?1 ratio. Payloads include small compounds (Dig-Cy5, Dig-Doxorubicin) and proteins (Dig-GFP). Complexed payloads are targeted by the bispecifics to cancer cells and because these complexes are stable in serum, they can be applied for targeted delivery. Because Dig bispecifics also effectively capture digoxigeninylated compounds under physiological conditions, separate administration of uncharged Dig bispecifics followed by application of Dig payload is sufficient to achieve antibody-mediated targeting in vitro and in vivo.

Metz, Silke; Haas, Alexander K.; Daub, Karin; Croasdale, Rebecca; Stracke, Jan; Lau, Wilma; Georges, Guy; Josel, Hans-Peter; Dziadek, Sebastian; Hopfner, Karl-Peter; Lammens, Alfred; Scheuer, Werner; Hoffmann, Eike; Mundigl, Olaf; Brinkmann, Ulrich

2011-01-01

140

Targeted Liposomal Drug Delivery to Monocytes and Macrophages  

PubMed Central

As the role of monocytes and macrophages in a range of diseases is better understood, strategies to target these cell types are of growing importance both scientifically and therapeutically. As particulate carriers, liposomes naturally target cells of the mononuclear phagocytic system (MPS), particularly macrophages. Loading drugs into liposomes can therefore offer an efficient means of drug targeting to MPS cells. Physicochemical properties including size, charge and lipid composition can have a very significant effect on the efficiency with which liposomes target MPS cells. MPS cells express a range of receptors including scavenger receptors, integrins, mannose receptors and Fc-receptors that can be targeted by the addition of ligands to liposome surfaces. These ligands include peptides, antibodies and lectins and have the advantages of increasing target specificity and avoiding the need for cationic lipids to trigger intracellular delivery. The goal for targeting monocytes/macrophages using liposomes includes not only drug delivery but also potentially a role in cell ablation and cell activation for the treatment of conditions including cancer, atherosclerosis, HIV, and chronic inflammation.

Kelly, Ciara; Jefferies, Caroline; Cryan, Sally-Ann

2011-01-01

141

Targeted drug delivery to treat pain and cerebral hypoxia.  

PubMed

Limited drug penetration is an obstacle that is often encountered in treatment of central nervous system (CNS) diseases including pain and cerebral hypoxia. Over the past several years, biochemical characteristics of the brain (i.e., tight junction protein complexes at brain barrier sites, expression of influx and efflux transporters) have been shown to be directly involved in determining CNS permeation of therapeutic agents; however, the vast majority of these studies have focused on understanding those mechanisms that prevent drugs from entering the CNS. Recently, this paradigm has shifted toward identifying and characterizing brain targets that facilitate CNS drug delivery. Such targets include the organic anion-transporting polypeptides (OATPs in humans; Oatps in rodents), a family of sodium-independent transporters that are endogenously expressed in the brain and are involved in drug uptake. OATP/Oatp substrates include drugs that are efficacious in treatment of pain and/or cerebral hypoxia (i.e., opioid analgesic peptides, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors). This clearly suggests that OATP/Oatp isoforms are viable transporter targets that can be exploited for optimization of drug delivery to the brain and, therefore, improved treatment of CNS diseases. This review summarizes recent knowledge in this area and emphasizes the potential that therapeutic targeting of OATP/Oatp isoforms may have in facilitating CNS drug delivery and distribution. Additionally, information presented in this review will point to novel strategies that can be used for treatment of pain and cerebral hypoxia. PMID:23343976

Ronaldson, Patrick T; Davis, Thomas P

2013-01-23

142

Targeted Cellular Drug Delivery using Tailored Dendritic Nanostructures  

NASA Astrophysics Data System (ADS)

Dendrimers and hyperbranched polymers possess highly branched architectures, with a large number of controllable, tailorble, ‘peripheral’ functionalities. Since the surface chemistry of these materials can be modified with relative ease, these materials have tremendous potential in targeted drug and gene delivery. The large number of end groups can also be tailored to create special affinity to targeted cells, and can also encapsulate drugs and deliver them in a controlled manner. We are developing tailor-modified dendritic systems for drug delivery. Synthesis, in-vitro drug loading, in-vitro drug delivery, and the targeting efficiency to the cell are being studied systematically using a wide variety of experimental tools. Polyamidoamine and Polyol dendrimers, with different generations and end-groups are studied, with drugs such as Ibuprofen and Methotrexate. Our results indicate that a large number of drug molecules can be encapsulated/attached to the dendrimers, depending on the end groups. The drug-encapsulated dendrimer is able to enter the cells rapidly and deliver the drug. Targeting strategies being explored

Kannan, Rangaramanujam; Kolhe, Parag; Kannan, Sujatha; Lieh-Lai, Mary

2002-03-01

143

The use of shear stress for targeted drug delivery.  

PubMed

Stenosed segments of arteries significantly alter the blood flow known from healthy vessels. In particular, the wall shear stress at critically stenosed arteries is at least an order of magnitude higher than in healthy situations. This alteration represents a change in physical force and might be used as a trigger signal for drug delivery. Mechano-sensitive drug delivery systems that preferentially release their payload under increased shear stress are discussed. Therefore, besides biological or chemical markers, physical triggers are a further principle approach for targeted drug delivery. We hypothesize that such a physical trigger is much more powerful to release drugs for vasodilation, plaque stabilization, or clot lysis at stenosed arteries than any known biological or chemical ones. PMID:23645574

Saxer, Till; Zumbuehl, Andreas; Müller, Bert

2013-05-02

144

CYCLOSTREPTIN DERIVATIVES SPECIFICALLY TARGET CELLULAR TUBULIN AND FURTHER MAP THE PACLITAXEL SITE†  

PubMed Central

Cyclostreptin is the first microtubule stabilizing agent whose mechanism of action was discovered to involve formation of a covalent bond with tubulin. Treatment of cells with cyclostreptin irreversibly stabilizes their microtubules because cyclostreptin forms a covalent bond to ?-tubulin at either the T220 or the N228 residue, located, respectively, at the microtubule pore and luminal taxoid binding sites. Due to its unique mechanism of action, cyclostreptin overcomes P-glycoprotein-mediated multidrug resistance in tumor cells. We used a series of reactive cyclostreptin analogues, 6-chloroacetyl-cyclostreptin, 8-chloroacetyl-cyclostreptin, and [14C-acetyl]-8-acetyl-cyclostreptin, to characterize the cellular target of the compound and to map the binding site. The three analogues were cytotoxic and stabilized microtubules in both sensitive and multidrug resistant tumor cells. In both types of cells, we identified ?-tubulin as the only or the predominantly labeled cellular protein, indicating that a covalent binding to microtubules is sufficient to prevent drug efflux mediated by P-glycoprotein. 6-chloroacetyl-cyclostreptin, 8-chloroacetyl-cyclostreptin, and 8-acetyl-cyclostreptin labeled both microtubules and unassembled tubulin at a single residue of the same tryptic peptide of ?-tubulin as was labeled by cyclostreptin (219-LTTPTYGDLNHLVSATMSGVTTCLR-243), but labeling with the analogues occurred at different positions of the peptide. 8-Acetyl-cyclostreptin reacted either with T220 or N228, as did the natural product, while 8-chloroacetyl-cyclostreptin formed a cross link to C241. Finally 6-chloroacetyl-cyclostreptin reacted with any one of the three residues, thus labeling the pathway for cyclostreptin-like compounds, leading from the pore where these compounds enter the microtubule to the luminal binding pocket.

Calvo, Enrique; Barasoain, Isabel; Matesanz, Ruth; Pera, Benet; Camafeita, Emilio; Pineda, Oriol; Hamel, Ernest; Vanderwal, Christopher D.; Andreu, Jose Manuel; Lopez, Juan A.; Diaz, Jose Fernando

2012-01-01

145

Paclitaxel-loaded microparticles for intratumoral administration via the TMT technique: preparation, characterization, and preliminary antitumoral evaluation.  

PubMed

In our pursuit to develop suitable therapeutic particulate systems for intratumoral delivery by the targeted multi-therapy (TMT) technique, we describe the preparation of paclitaxel-loaded poly(D,L-lactic-co-glycolic) acid (PLGA) microparticles (MPs) (drug loading 35-38%, wt/wt; size 0.7-5 microm). Magnetite (15%, wt/wt) was also incorporated in some preparations for a future magnetic resonance imaging (MRI)-guided delivery. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) experiments showed that paclitaxel was not encapsulated in its initial crystalline form. The paclitaxel in vitro release pattern showed a biphasic tendency with a burst effect followed by a sustained release (28% released amount after 1 month), which was accompanied with MP erosion and degradation signs as confirmed by scanning electronic microscopy (SEM) micrographs. The paclitaxel-loaded MPs demonstrated a dose-dependent antitumor effect on human uterine cancer cells, with an IC(50) value relatively close to that of commercial Taxol. This paclitaxel delivery system represents a potent antiprofilerative and radiosensitizer agent for intratumoral administration via the TMT technique. PMID:18612910

Hamoudeh, Misara; Diab, Roudayna; Fessi, Hatem; Dumontet, Charles; Cuchet, Delphine

2008-07-01

146

Hydrotropic polymeric mixed micelles based on functional hyperbranched polyglycerol copolymers as hepatoma-targeting drug delivery system.  

PubMed

Mixed copolymer nanoparticles (NPs) self-assembled from ?-cyclodextrin-grafted hyperbranched polyglycerol (HPG-g-CD) and lactobionic acid (LA)-grafted hyperbranched polyglycerol (HPG-g-LA) were applied as carriers for a hydrophobic antitumor drug, paclitaxel (PTX), achieving hepatocellular carcinoma-targeted delivery. The resulting NPs exhibited high drug loading capacity and substantial stability in aqueous solution. In vitro drug release studies demonstrated a controlled drug release profile with increased release at acidic pH. Remarkably, tumor proliferation assays showed that PTX-loaded mixed copolymer NPs inhibited asialoglycoprotein (ASGP) receptor positive HepG2 cell proliferation in a concentration-dependent manner in comparison with ASGP receptor negative BGC-823 cells. Moreover, the competition assay demonstrated that the small molecular LA inhibited the cellular uptake of the PTX-loaded mixed copolymer NPs, indicating the ASGP receptor-mediated endocytosis in HepG2 cells. In addition, the intracellular uptake tests by confocal laser scanning microscopy showed that the mixed copolymer NPs were more efficiently taken up by HepG2 cells compared with HPG-g-CD NPs. These results suggest a feasible application of the mixed copolymer NPs as nanocarriers for hepatoma-targeted delivery of potent antitumor drugs. PMID:23132353

Zhang, Xuejiao; Zhang, Xinge; Yu, Peien; Han, Yucai; Li, Yangguang; Li, Chaoxing

2012-11-06

147

Nanostructured lipid carriers (NLCs) for drug delivery and targeting.  

PubMed

Nanostructured lipid carriers (NLCs) are drug-delivery systems composed of both solid and liquid lipids as a core matrix. It was shown that NLCs reveal some advantages for drug therapy over conventional carriers, including increased solubility, the ability to enhance storage stability, improved permeability and bioavailability, reduced adverse effect, prolonged half-life, and tissue-targeted delivery. NLCs have attracted increasing attention in recent years. This review describes recent developments in drug delivery using NLCs strategies. The structures, preparation techniques, and physicochemical characterization of NLCs are systematically elucidated in this review. The potential of NLCs to be used for different administration routes is highlighted. Special attention is paid to parenteral injection and topical delivery since these are the most common routes for investigating NLCs. Relevant issues for the introduction of NLCs to market, including pharmaceutical and cosmetic applications, are discussed. The related patents of NLCs for drug delivery are also reviewed. Finally, the future development and current obstacles needing to be resolved are elucidated. PMID:22946628

Fang, Chia-Lang; Al-Suwayeh, Saleh A; Fang, Jia-You

2013-01-01

148

Targeted gene knockout by direct delivery of ZFN proteins  

PubMed Central

Zinc-finger nucleases (ZFNs) are versatile reagents that have redefined genome engineering. Realizing the full potential of this technology requires the development of safe and effective methods for delivering ZFNs into cells. We demonstrate the intrinsic cell-penetrating capabilities of the standard ZFN architecture and show that direct delivery of ZFNs as proteins leads to efficient endogenous gene disruption in a variety of mammalian cell types with minimal off-target effects.

Gaj, Thomas; Guo, Jing; Kato, Yoshio; Sirk, Shannon J.; Barbas, Carlos F.

2012-01-01

149

Nanofabricated biomimetic structures for smart targeting and drug delivery  

Microsoft Academic Search

We present a new approach to hybrid artificial cells (AC) designed for specific targeting and active drug delivery by combining\\u000a an impermeable non-biological scaffold with an artificial bilayer lipid membrane (BLM) that supports the functioning bio-molecules\\u000a required to provide AC functionality. We report on the fabrication of the scaffold using nanotechnology, as well as on loading\\u000a of the scaffold and

Alma Dudia; Johannes S. Kanger; Vinod Subramaniam

2005-01-01

150

Carbon nanotube lipid drug approach for targeted delivery of a chemotherapy drug in a human breast cancer xenograft animal model.  

PubMed

Carbon nanotube (CNT) possesses excellent properties as a drug carrier. To overcome the challenge of drug functionalization with CNT, we have developed a lipid-drug approach for efficient drug loading onto CNT, in which a long chain lipid molecule is conjugated to the drug molecule so that the lipid-drug can be loaded directly onto CNT through binding of the lipid 'tail' in the drug molecule to CNT surfaces via hydrophobic interactions. In a proof-of-concept study, drug paclitaxel (PTX) was conjugated with a non-toxic lipid molecule docosanol for functionalization with CNT. Folic acid was also conjugated to CNT for targeted drug delivery. High level of drug loading onto SWNT could be achieved by lipid-drug approach. Conjugation of FA to SWNT-lipid-PTX led to an increase in cell penetration capacity, and the targeted SWNT-lipid-PTX showed much improved drug efficacy in vitro in comparison to free drug Taxol and non-targeted SWNT-lipid-PTX at 48 h (78.5% vs. 31.6% and 59.1% in cytotoxicity respectively, p < 0.01). In vivo analysis using a human breast cancer xenograft mice model also confirmed the improved drug efficacy. The targeted SWNT-lipid-PTX was found non-toxic as evaluated by biochemical analysis using blood samples, and by histological analysis of major organs. PMID:24060420

Shao, Wei; Paul, Arghya; Zhao, Bin; Lee, Crystal; Rodes, Laetitia; Prakash, Satya

2013-09-20

151

Magnetic lymphatic targeting drug delivery system using carbon nanotubes.  

PubMed

By controlling size, nanoparticles can be effectively taken up into lymphatics. On this basis, various nanoparticles have been investigated for transporters of chemotherapeutic pharmaceuticals, but only a few were retained in the draining lymph node. Here, we present a technology using a magnetic carbon nanotubes (MNTs) delivery system, and it may be possible to facilitate the targeted delivery of drugs in the lymphatic tissue more effectively. Chemotherapeutic agents were incorporated into the pores of functionalized MNTs synthesized with a layer of magnetite nanoparticles on the inner surface of the nanotubes. To improve drug delivery to cancer cells in the lymph nodes, individualized MNTs were noncovalently functionalized by folic acid (FA). By using an externally placed magnet to guide the drug matrix to the regional targeted lymph nodes, the MNTs can be retained in the draining targeted lymph nodes for several days and continuously release chemotherapeutic drugs. Selective killing of tumor cells overexpressing the folate receptors (FRs) in the lymph nodes can be achieved, as FR is overexpressed across a broad spectrum of human tumors. PMID:17910909

Yang, Feng; Fu, De Liang; Long, Jiang; Ni, Quan Xing

2007-10-01

152

Multifunctional inorganic nanoparticles for imaging, targeting, and drug delivery  

NASA Astrophysics Data System (ADS)

Multifunctional silica nanoparticles provide a framework for the attachment of imaging and targeting agents for applications in spectroscopy, microscopy, and biology while simultaneously serving as supports for molecular machines for the controlled release of cargo. The deliberate placing of molecules or other nanoparticles within specific regions of the mesostructure or the surface of the nanoparticles allows for multiple modes of characterization and application. This review focuses on research related to fluorescence and spectroscopic imaging techniques, targeting strategies to increase particle uptake efficiency in cells, and on demand drug delivery regulated by molecular machines.

Pecorelli, Travis A.; Dibrell, Marcelle M.; Li, Zongxi; Thomas, Courtney R.; Zink, Jeffrey I.

2010-02-01

153

In vivo targeted delivery of nanoparticles for theranosis.  

PubMed

Therapy and diagnosis are two major categories in the clinical treatment of disease. Recently, the word "theranosis" has been created, combining the words to describe the implementation of these two distinct pursuits simultaneously. For successful theranosis, the efficient delivery of imaging agents and drugs is critical to provide sufficient imaging signal or drug concentration in the targeted disease site. To achieve this purpose, biomedical researchers have developed various nanoparticles composed of organic or inorganic materials. However, the targeted delivery of these nanoparticles in animal models and patients remains a difficult hurdle for many researchers, even if they show useful properties in cell culture condition. In this Account, we review our strategies for developing theranostic nanoparticles to accomplish in vivo targeted delivery of imaging agents and drugs. By applying these rational strategies, we achieved fine multimodal imaging and successful therapy. Our first strategy involves physicochemical optimization of nanoparticles for long circulation and an enhanced permeation and retention (EPR) effect. We accomplished this result by testing various materials in mouse models and optimizing the physical properties of the materials with imaging techniques. Through these experiments, we developed a glycol chitosan nanoparticle (CNP), which is suitable for angiogenic diseases, such as cancers, even without an additional targeting moiety. The in vivo mechanism of this particle was examined through rationally designed experiments. In addition, we evaluated and compared the biodistribution and target-site accumulation of bare and drug-loaded nanoparticles. We then focus on the targeting moieties that bind to cell surface receptors. Small peptides were selected as targeting moieties because of their stability, low cost, size, and activity per unit mass. Through phage display screening, the interleukin-4 receptor binding peptide was discovered, and we combined it with our nanoparticles. This product accumulated efficiently in atherosclerotic regions or tumors during both imaging and therapy. We also developed hyaluronic acid nanoparticles that can bind efficiently to the CD44 antigen receptors abundant in many tumor cells. Their delivery mechanism is based on both physicochemical optimization for the EPR effect and receptor-mediated endocytosis by their hyaluronic acid backbone. Finally, we introduce the stimuli-responsive system related to the chemical and biological changes in the target disease site. Considering the relatively low pH in tumors and ischemic sites, we applied pH-sensitive micelle to optical imaging, magnetic resonance imaging, anticancer drug delivery, and photodynamic therapy. In addition, we successfully evaluated the in vivo imaging of enzyme activity at the target site with an enzyme-specific peptide sequence and CNPs. On the basis of these strategies, we were able to develop self-assembled nanoparticles for in vivo targeted delivery, and successful results were obtained with them in animal models for both imaging and therapy. We anticipate that these rational strategies, as well as our nanoparticles, will be applied in both the diagnosis and therapy of many human diseases. These theranostic nanoparticles are expected to greatly contribute to optimized therapy for individual patients as personalized medicine, in the near future. PMID:21851104

Koo, Heebeom; Huh, Myung Sook; Sun, In-Cheol; Yuk, Soon Hong; Choi, Kuiwon; Kim, Kwangmeyung; Kwon, Ick Chan

2011-08-18

154

Multiscale Modeling of Functionalized Nanocarriers in Targeted Drug Delivery  

PubMed Central

Targeted drug delivery using functionalized nanocarriers (NCs) is a strategy in therapeutic and diagnostic applications. In this paper we review the recent development of models at multiple length and time scales and their applications to targeting of antibody functionalized nanocarriers to antigens (receptors) on the endothelial cell (EC) surface. Our mesoscale (100 nm-1 ?m) model is based on phenomenological interaction potentials for receptor-ligand interactions, receptor-flexure and resistance offered by glycocalyx. All free parameters are either directly determined from independent biophysical and cell biology experiments or estimated using molecular dynamics simulations. We employ a Metropolis Monte Carlo (MC) strategy in conjunction with the weighted histogram analysis method (WHAM) to compute the free energy landscape (potential of mean force or PMF) associated with the multivalent antigen-antibody interactions mediating the NC binding to EC. The binding affinities (association constants) are then derived from the PMF by computing absolute binding free energy of binding of NC to EC, taking into account the relevant translational and rotational entropy losses of NC and the receptors. We validate our model predictions by comparing the computed binding affinities and PMF to a wide range of experimental measurements, including in vitro cell culture, in vivo endothelial targeting, atomic force microscopy (AFM), and flow chamber experiments. The model predictions agree closely and quantitatively with all types experimental measurements. On this basis, we conclude that our computational protocol represents a quantitative and predictive approach for model driven design and optimization of functionalized NCs in targeted vascular drug delivery.

Liu, Jin; Bradley, Ryan; Eckmann, David M.; Ayyaswamy, Portonovo S.; Radhakrishnan, Ravi

2011-01-01

155

Magnetic nanoparticles as targeted delivery systems in oncology  

PubMed Central

Background Many different types of nanoparticles, magnetic nanoparticles being just a category among them, offer exciting opportunities for technologies at the interfaces between chemistry, physics and biology. Some magnetic nanoparticles have already been utilized in clinical practice as contrast enhancing agents for magnetic resonance imaging (MRI). However, their physicochemical properties are constantly being improved upon also for other biological applications, such as magnetically-guided delivery systems for different therapeutics. By exposure of magnetic nanoparticles with attached therapeutics to an external magnetic field with appropriate characteristics, they are concentrated and retained at the preferred site which enables the targeted delivery of therapeutics to the desired spot. Conclusions The idea of binding chemotherapeutics to magnetic nanoparticles has been around for 30 years, however, no magnetic nanoparticles as delivery systems have yet been approved for clinical practice. Recently, binding of nucleic acids to magnetic nanoparticles has been demonstrated as a successful non-viral transfection method of different cell lines in vitro. With the optimization of this method called magnetofection, it will hopefully become another form of gene delivery for the treatment of cancer.

Prijic, Sara; Sersa, Gregor

2011-01-01

156

Chlorotoxin labeled magnetic nanovectors for targeted gene delivery to glioma.  

PubMed

Glioma accounts for 80% of brain tumors and currently remains one of the most lethal forms of cancers. Gene therapy could potentially improve the dismal prognosis of patients with glioma, but this treatment modality has not yet reached the bedside from the laboratory due to the lack of safe and effective gene delivery vehicles. In this study we investigate targeted gene delivery to C6 glioma cells in a xenograft mouse model using chlorotoxin (CTX) labeled nanoparticles. The developed nanovector consists of an iron oxide nanoparticle core, coated with a copolymer of chitosan, polyethylene glycol (PEG), and polyethylenimine (PEI). Green fluorescent protein (GFP) encoding DNA was bound to these nanoparticles, and CTX was then attached using a short PEG linker. Nanoparticles without CTX were also prepared as a control. Mice bearing C6 xenograft tumors were injected intravenously with the DNA-bound nanoparticles. Nanoparticle accumulation in the tumor site was monitored using magnetic resonance imaging and analyzed by histology, and GFP gene expression was monitored through Xenogen IVIS fluorescence imaging and confocal fluorescence microscopy. Interestingly, the CTX did not affect the accumulation of nanoparticles at the tumor site but specifically enhanced their uptake into cancer cells as evidenced by higher gene expression. These results indicate that this targeted gene delivery system may potentially improve treatment outcome of gene therapy for glioma and other deadly cancers. PMID:20731441

Kievit, Forrest M; Veiseh, Omid; Fang, Chen; Bhattarai, Narayan; Lee, Donghoon; Ellenbogen, Richard G; Zhang, Miqin

2010-08-24

157

Multifunctional Particles for Melanoma-Targeted Drug Delivery  

PubMed Central

New magnetic-based core-shell particles (MBCSP) were developed to target skin cancer cells while delivering chemotherapeutic drugs in a controlled fashion. MBCSP consist of a thermo-responsive shell of poly(N-isopropylacrylamide-acrylamide-allylamine) and a core of poly(lactic-co-glycolic acid) (PLGA) embedded with magnetite nanoparticles. To target melanoma cancer cells, MBCSP were conjugated with Gly-Arg-Gly-Asp-Ser (GRGDS) peptides that specifically bind to the ?5?3+ receptor of melanoma cell. MBCSP consist of unique multifunctional and controlled drug delivery characteristics. Specially, they can provide dual drug release mechanisms (a sustained release of drugs through degradation of PLGA core and a controlled release in response to changes in temperature via thermo-responsive polymer shell), and dual targeting mechanisms (magnetic localization and receptor-mediated targeting). Results from in vitro studies indicate that GRGDS-conjugated MBCSP has an average diameter of 296 nm and exhibit no cytotoxicity towards human dermal fibroblasts up to 500 ?g ml?1. Further, a sustained release of curcumin from the core and a temperature-dependent release of doxorubicin from the shell of MBCSP were observed. The particles also produced a dark contrast signal in magnetic resonance imaging. Finally, the particles were accumulated at the tumor site in a B16F10 melanoma orthotopic mouse model, especially in presence of a magnet. Results indicate great potential of MBCSP as a platform technology to target, treat, and monitor melanoma for targeted drug delivery to reduce side effects of chemotherapeutic reagents.

Wadajkar, Aniket S.; Bhavsar, Zarna; Ko, Cheng-Yu; Koppolu, Bhanuprasanth; Cui, Weina; Tang, Liping; Nguyen, Kytai T.

2012-01-01

158

"Nanotheranostics" for tumor imaging and targeted drug delivery  

NASA Astrophysics Data System (ADS)

The magnetic resonance imaging (MRI) technique is a promising tool that improves cancer detection, facilitates diagnosis and monitors therapeutic effects. Superparamagnetic iron oxide nanoparticles (SPIOs) have emerged as MRI contrast agents for tumor imaging and as potential vectors for targeted anti-cancer drug delivery; nevertheless, the application of SPIOs has been hampered due to a lack of specificity to tumor tissues and premature drug release. This project aims at developing multifunctional SPIOs for both cancer imaging and targeted drug delivery via conjugation of tumor specific antibodies with SPIOs. The application of anti-TAG-72 antibodies as tumor targeting modalities was evaluated in cultured colorectal cancer cells and in xenograft models by using fluorescent imaging and positron emission tomography (PET) imaging. It was demonstrated that antibody-labeled SPIOs were superior imaging agents and drug carriers for increased tumor specificity. The regulation and kinetics of intracellular drug release from SPIOs were explored by means of fluorescence imaging. In vitro and in vivo fluorescence resonance energy transfer (FRET) imaging was employed to investigate the mechanisms of premature drug release from nanocarriers. The large volume and high hydrophobicity of cell membranes were found to play an important role in premature drug release. The encapsulation of SPIOs into nanocarriers decreased drug release in a dose-dependent mode. This study provided future opportunities to improve the efficiency of nanocarriers by exploring the mechanism of drug release and disassembly of SPIO-loaded polymeric nanoparticles.

Zou, Peng

159

Development of magnetically targeted drug delivery system using superconducting magnet  

NASA Astrophysics Data System (ADS)

Development of a novel drug delivery system was made to accumulate/navigate magnetic drugs with the help of a superconducting magnet in order to control the drugs in blood vessels located deep inside the body. In the present paper, we tested the feasibility of a novel navigation system, made by applying a strong external (magnetic) field through SmBaCuO and YBaCuO bulk superconductors in order to realize the practice of using externally applied magnetic fields for targeting the magnetic particles to a circumscribed body region.

Takeda, Shin-Ichi; Mishima, Fumihito; Fujimoto, Suketaka; Izumi, Yoshinobu; Nishijima, Shigehiro

2007-04-01

160

Angiopep-conjugated poly(ethylene glycol)-co-poly(?-caprolactone) nanoparticles as dual-targeting drug delivery system for brain glioma.  

PubMed

Dual-targeting nanoparticle drug delivery system was developed by conjugating Angiopep with PEG-PCL nanoparticles (ANG-NP) through bifunctional PEG to overcome the limitations of low transport of chemotherapeutics across the Blood-brain barrier (BBB) and poor penetration into tumor tissue. ANG-NP can target the low-density lipoprotein receptor-related protein (LRP) which is over-expressed on the BBB and glioma cells. Compared with non-targeting nanoparticles, a significantly higher amount of rhodamine isothiocyanate-labeled dual-targeting nanoparticles were endocytosed by U87 MG cells. The antiproliferative and cell apoptosis assay of paclitaxel-loaded ANG-NP (ANG-NP-PTX) demonstrated that ANG-NP-PTX resulted in enhanced inhibitory effects to U87 MG glioma cells. The transport ratios across the BBB model in vitro were significantly increased and the cell viability of U87 MG glioma cells after crossing the BBB was obviously decreased by ANG-NP-PTX. Enhanced accumulation of ANG-NP in the glioma bed and infiltrating margin of intracranial U87 MG glioma tumor-bearing in vivo model were observed by real time fluorescence image. In conclusion, Angiopep-conjugated PEG-PCL nanoparticles were prospective in dual-targeting drug delivery system for targeting therapy of brain glioma. PMID:21427009

Xin, Hongliang; Jiang, Xinyi; Gu, Jijin; Sha, Xianyi; Chen, Liangcen; Law, Kitki; Chen, Yanzuo; Wang, Xiao; Jiang, Ye; Fang, Xiaoling

2011-03-21

161

Tumor Regression by Targeted Gene Delivery to the Neovasculature  

NASA Astrophysics Data System (ADS)

Efforts to influence the biology of blood vessels by gene delivery have been hampered by a lack of targeting vectors specific for endothelial cells in diseased tissues. Here we show that a cationic nanoparticle (NP) coupled to an integrin ?v?3-targeting ligand can deliver genes selectively to angiogenic blood vessels in tumor-bearing mice. The therapeutic efficacy of this approach was tested by generating NPs conjugated to a mutant Raf gene, ATP?-Raf, which blocks endothelial signaling and angiogenesis in response to multiple growth factors. Systemic injection of the NP into mice resulted in apoptosis of the tumor-associated endothelium, ultimately leading to tumor cell apoptosis and sustained regression of established primary and metastatic tumors.

Hood, John D.; Bednarski, Mark; Frausto, Ricardo; Guccione, Samira; Reisfeld, Ralph A.; Xiang, Rong; Cheresh, David A.

2002-06-01

162

Nanostructured porous Si-based nanoparticles for targeted drug delivery.  

PubMed

One of the backbones in nanomedicine is to deliver drugs specifically to unhealthy cells. Drug nanocarriers can cross physiological barriers and access different tissues, which after proper surface biofunctionalization can enhance cell specificity for cancer therapy. Recent developments have highlighted the potential of mesoporous silica (PSiO(2)) and silicon (PSi) nanoparticles for targeted drug delivery. In this review, we outline and discuss the most recent advances on the applications and developments of cancer therapies by means of PSiO(2) and PSi nanomaterials. Bio-engineering and fine tuning of anti-cancer drug vehicles, high flexibility and potential for sophisticated release mechanisms make these nanostructures promising candidates for "smart" cancer therapies. As a result of their physicochemical properties they can be controllably loaded with large amounts of drugs and coupled to homing molecules to facilitate active targeting. The main emphasis of this review will be on the in vitro and in vivo studies. PMID:23507894

Shahbazi, Mohammad-Ali; Herranz, Barbara; Santos, Hélder A

163

Hypertension control through the design of targeted delivery models.  

PubMed Central

If we discard some of the assumptions upon which curatively oriented medical care is based, we can design models to deliver more effective services for those with chronic diseases. Assumptions to be discarded are--that disease processes can be cured through the delivery of a "magic bullet" rather than controlled through continuous surveillance, -that the physician must be an active decision maker and thus act as gatekeeper and monitor for all disease victims, and -that care for a family of consumers must be provided together. Models for the delivery of services can then be designed to provide continuity of care for those with a specific chronic disease, and paraprofessionals can be used as gatekeepers and monitors, in combination with physicians, rather than physicians alone, to give services. Models can be targeted to reach specific high-risk groups within the population at the workplace, the school, unemployment office, or wherever groups routinely congregate for purposes other than health care. Building targeted models requires extensive knowledge of the specific geographic area and its population as well as knowledge of the natural history of the disease and its treatment. For hypertension programs, goals can be set in terms of numbers of persons whose disease is controlled and the number of new programs initiated as the result of the control efforts.

Bloom, J R

1978-01-01

164

Multiparticulate System for Colon Targeted Delivery of Ondansetron  

PubMed Central

Targeted delivery of drugs to colon has the potential for local treatment of a variety of colonic diseases. The main objective of the study was to develop a multiparticulate system containing chitosan microspheres for the colon targeted delivery of ondansetron for the treatment of irritable bowel syndrome. This work combines pH-dependent solubility of eudragit S-100 polymers and microbial degradability of chitosan polymers. Chitosan microspheres containing ondansetron were prepared by emulsion cross linking method. The effect of process variables like chitosan concentration, drug-polymer ratio, emulsifier concentration and stirring speed were studied on particle size and entrapment efficiency of chitosan microspheres. In vitro drug release studies in simulated gastro intestinal fluids showed a burst drug release pattern in the initial hour necessitating microencapsulation around the chitosan microspheres. The optimized formulation was then subjected to microencapsulation with eudragit S-100 by solvent evaporation technique. The effect of different coat/core ratio on particle size, drug entrapment efficiency and in vitro drug release were studied. Formulation which contain 1:10 core/coat ratio released lesser amount of drug in the upper gastro intestinal conditions and so selected as best formulation and then subjected to in vitro drug release studies in presence of rat ceacal contents to assess biodegradability of chitosan microspheres in colon. In order to study the drug release mechanism in vitro drug release data was fitted into various kinetic models. Analysis of regression values suggested that the possible drug release mechanism was Peppas model.

Jose, S.; Dhanya, K.; Cinu, T. A.; Aleykutty, N. A.

2010-01-01

165

Multiparticulate system for colon targeted delivery of ondansetron.  

PubMed

Targeted delivery of drugs to colon has the potential for local treatment of a variety of colonic diseases. The main objective of the study was to develop a multiparticulate system containing chitosan microspheres for the colon targeted delivery of ondansetron for the treatment of irritable bowel syndrome. This work combines pH-dependent solubility of eudragit S-100 polymers and microbial degradability of chitosan polymers. Chitosan microspheres containing ondansetron were prepared by emulsion cross linking method. The effect of process variables like chitosan concentration, drug-polymer ratio, emulsifier concentration and stirring speed were studied on particle size and entrapment efficiency of chitosan microspheres. In vitro drug release studies in simulated gastro intestinal fluids showed a burst drug release pattern in the initial hour necessitating microencapsulation around the chitosan microspheres. The optimized formulation was then subjected to microencapsulation with eudragit S-100 by solvent evaporation technique. The effect of different coat/core ratio on particle size, drug entrapment efficiency and in vitro drug release were studied. Formulation which contain 1:10 core/coat ratio released lesser amount of drug in the upper gastro intestinal conditions and so selected as best formulation and then subjected to in vitro drug release studies in presence of rat ceacal contents to assess biodegradability of chitosan microspheres in colon. In order to study the drug release mechanism in vitro drug release data was fitted into various kinetic models. Analysis of regression values suggested that the possible drug release mechanism was Peppas model. PMID:20582191

Jose, S; Dhanya, K; Cinu, T A; Aleykutty, N A

2010-01-01

166

Polyelectrolyte Nanogels Decorated with Monoclonal Antibody for Targeted Drug Delivery  

PubMed Central

Novel surface-functionalized cross-linked nanogels were developed as a platform to allow conjugation of monoclonal antibodies (mAb) for targeted drug delivery. Well-defined diblock copolymers of poly(ethylene glycol)-b-poly(methacrylic acid) (PEG-b-PMA) with PEG terminal aldehyde functionality were synthesized by atom transfer radical polymerization (ATRP) and characterized by GPC and 1H NMR. These copolymers were used to prepare nanogels via condensation of PEG-b-PMA with Ca2+ ions into micelle-like aggregates, cross-linking of the PMA/Ca2+ cores and removal of Ca2+ ions. The resulting nanogels represent highly swollen spherical polyelectrolyte particles with free terminal aldehyde functionalities at the nonionic PEG chains. A reductive amination reaction between aldehyde groups and amino groups of mAb resulted in effective conjugation to the nanogels of mAb CC49 against tumor-associated glycoprotein 72 (TAG-72). The mAb retained the binding affinity to bovine submaxillary mucin after conjugation as shown by surface plasmon resonance (SPR). Therefore, aldehyde functionalized nanogels can be linked to mAb using a simple, one-step approach. They may have potential for targeted delivery of diagnostic and therapeutic agents to tumors.

Nukolova, Nataliya V.; Yang, Zigang; Kim, Jong Oh; Kabanov, Alexander V.; Bronich, Tatiana K.

2010-01-01

167

PLGA Nanoparticles Stabilized with Cationic Surfactant: Safety Studies and Application in Oral Delivery of Paclitaxel to Treat Chemical-Induced Breast Cancer in Rat  

Microsoft Academic Search

Purpose  This study was carried out to formulate poly(lactide-co-glycolide) (PLGA) nanoparticles using a quaternary ammonium salt didodecyl\\u000a dimethylammonium bromide (DMAB) and checking their utility to deliver paclitaxel by oral route.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Particles were prepared by emulsion solvent diffusion evaporation method. DMAB and particles stabilized with it were evaluated\\u000a by MTT and LDH cytotoxicity assays. Paclitaxel was encapsulated in these nanoparticles and evaluated

V. Bhardwaj; D. D. Ankola; S. C. Gupta; M. Schneider; C.-M. Lehr; M. N. V. Ravi Kumar

2009-01-01

168

Delivery of Retinoid-Based Therapies To Target Tissues†  

PubMed Central

Through its various metabolites, vitamin A controls essential physiological functions. Both naturally occurring metabolites and novel retinoid analogues have shown effectiveness in many clinical settings that include skin diseases and cancer, and in animal models of human conditions affecting vision. In this review, we analyze several potential retinoid-based therapies from the point of view of drug metabolism and transport to target tissues. We focus on the endogenous factors that affect the absorption, transport, and metabolism of retinoids by taking into account data obtained from the analysis of animal models that lack the enzymes or proteins involved in the storage and absorption of retinoids. We also discuss findings of toxicity associated with retinoids in an effort to improve the outcome of retinoid-based therapies. In this context, we review evidence that esterification of retinol and retinol-based drugs within target tissues provides one of the most efficient means to improve the absorption and to reduce the toxicity associated with pharmacological doses of retinoids. Future retinoid-based therapeutic strategies could involve targeted delivery mechanisms leading to lower toxicity and improved effectiveness of retinoids.

Moise, Alexander R.; Noy, Noa; Palczewski, Krzysztof; Blaner, William S.

2008-01-01

169

Lactosylated liposomes for targeted delivery of doxorubicin to hepatocellular carcinoma  

PubMed Central

Background N-lactosyl-dioleoylphosphatidylethanolamine (Lac-DOPE) was synthesized and evaluated as a liver-specific targeting ligand via asialoglycoprotein receptors for liposomal delivery of doxorubicin. Methods Lactosylated liposomes encapsulating calcein (Lac-L-calcein) or doxorubicin (Lac-L-DOX) composed of egg phosphatidylcholine, cholesterol, monomethoxy polyethylene glycol 2000-distearoyl phosphatidylethanolamine, and Lac-DOPE at 50:35:5:10 (mol/mol) were prepared by polycarbonate membrane extrusion and evaluated in human hepatocellular carcinoma HepG2 cells. Cellular uptake of Lac-L-calcein was monitored by confocal microscopy and by flow cytometry. The cytotoxicity of Lac-L-DOX was evaluated by MTT assay. The pharmacokinetic properties of Lac-L-DOX were studied in normal mice, and its biodistribution and antitumor activity were studied in nude mice with HepG2 xenografts. Results The size of Lac-L-DOX was less than 100 nm and the liposomes demonstrated excellent colloidal stability. In vitro uptake of Lac-L-calcein by HepG2 cells was four times greater than that of non-targeted L-calcein. In the presence of 20 mM lactose, the uptake of Lac-L-calcein was inhibited, suggesting that asialoglycoprotein receptors mediated the observed cellular uptake. Lac-L-DOX exhibited enhanced in vivo cytotoxicity compared with the nontargeted liposomal doxorubicin (L-DOX), and its pharmacokinetic parameters indicate that Lac-L-DOX has a long blood circulation time (t1/2 8.73 hours). Tissue distribution and therapeutic efficacy studies in nude mice bearing HepG2 xenografts show that Lac-L-DOX had significantly stronger tumor inhibitory activity compared with L-DOX and free doxorubicin, along with a higher accumulation of drug within the tumor site and greater cellular uptake by tumor cells. Conclusion These data suggest that lactosylated liposomes are promising drug delivery vehicles for hepatocellular carcinoma.

Zhou, Xiaoju; Zhang, Mengzi; Yung, Bryant; Li, Hong; Zhou, Chenguang; Lee, L James; Lee, Robert J

2012-01-01

170

Tumor-targeted delivery of biologically active TRAIL protein  

PubMed Central

The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a potent inducer of tumor cell apoptosis, but concerns of considerable liver toxicity limit its uses in human cancer therapy. Here, we show that i.v. injected Escherichia coli DH5? (E. coli DH5?) specifically replicates in solid tumors and metastases in live animals. E. coli DH5? does not enter tumor cells and suits for being the vector for soluble TRAIL (sTRAIL), which induces apoptosis by activating cell-surface death receptors. With the high ‘tumor-targeting' nature, we demonstrate that intratumoral (i.t.) and intravenous injection of sTRAIL-expressing E. coli DH5? results in the tumor-targeted release of biologically active molecules, which leads to a dramatic reduction in the tumor growth rate and the prolonged survival of tumor-bearing mice. TRAIL delivery by E. coli DH5? did not cause any detectable toxicity to any organs, suggesting that E. coli DH5?-delivered sTRAIL protein therapy may provide a feasible and effective form of treatment for solid tumors.

Zhang, H-Y; Man, J-H; Liang, B; Zhou, T; Wang, C-H; Li, T; Li, H-Y; Li, W-H; Jin, B-F; Zhang, P-J; Zhao, J; Pan, X; He, K; Gong, W-L; Zhang, X-M; Li, A-L

2010-01-01

171

Development of colon targeted drug delivery systems for mebendazole.  

PubMed

The objective of the present study is to develop colon targeted drug delivery systems for mebendazole using guar gum as a carrier. Matrix tablets containing various proportions of guar gum were prepared by wet granulation technique using starch paste as a binder. The tablets were evaluated for drug content uniformity, and were subjected to in vitro drug release studies. The amount of mebendazole released from the matrix tablets at different time intervals was estimated by a high-performance liquid chromatography method. Guar gum matrix tablets released 8-15% of the mebendazole in the physiological environment of stomach and small intestine depending on the proportion of guar gum used in the formulation. When the dissolution study was continued in simulated colonic fluids the matrix tablets containing 20% of guar gum released another 83% of mebendazole after degradation into 2-3 pieces. The matrix tablets containing 30% of guar gum also released about 50% of mebendazole in simulated colonic fluids indicating the susceptibility of the guar gum formulations to the rat caecal contents. The results of the study show that matrix tablets containing either 20% or 30% of guar gum are most likely to provide targeting of mebendazole for local action in the colon. The mebendazole matrix tablets containing either 20% or 30% of guar gum showed no change either in physical appearance, drug content or dissolution pattern after storage at 45 degrees C/75% relative humidity for 3 months. Differential scanning calorimetry indicated no possibility of interaction between mebendazole and guar gum. PMID:11689262

Krishnaiah, Y S; Veer Raju, P; Dinesh Kumar, B; Bhaskar, P; Satyanarayana, V

2001-11-01

172

Transcranial Route of Brain Targeted Delivery of Methadone in Oil  

PubMed Central

The unique anatomical arrangement of blood vessels and sinuses in the human skull and the brain, the prevalence of a high density of skin appendages in the scalp, extracranial vessels of the scalp communicating with the brain via emissary veins and most importantly, the way that the scalp is used in Ayurvedic medical system in treating diseases associated with the brain show that a drug could be transcranially delivered and targeted to the brain through the scalp. The present study was to investigate by measuring the antinociceptive effect on rats whether the opioid analgesic methadone could be delivered and targeted to the brain by transcranial delivery route. A non aqueous solution of methadone base in sesame oil was used for the application on the scalp. Animal studies were carried out using six groups of male rats consisting of group 1, the oral control treated with distilled water 1 ml; group 2, the oral positive control treated with methadone hydrochloride solution 316.5 ?g/ml; group 3, the negative control treated transcranially with the blank sesame oil 0.2 ml and three test groups 4, 5 and 6 treated with three different dose levels of the transcranial oil formulation of methadone base, 41.6 ?g/0.2 ml, 104 ?g/0.2 ml and 208 ?g/0.2 ml, respectively. The antinociceptive effects were examined by subjecting the rats to the hot plate and tail flick tests. The two higher concentrations of the three transcranial methadone formulations yielded response vs time curves showing nearly equal maximum antinociceptive effects similar to that of the oral positive control. Maximum analgesic effect after transcranial administration was observed between 1st and 2nd h and declined up to 6th hour. The results indicate that the transcranial brain targeted delivery of methadone base in the form of an oil based non aqueous solution results in statistically significant antinociceptive effects under experimental conditions. Therefore, it is possible to deliver central nervous system drugs through the proposed transcranial route when suitably formulated.

Pathirana, W.; Abhayawardhana, P.; Kariyawasam, H.; Ratnasooriya, W. D.

2009-01-01

173

Transcranial route of brain targeted delivery of methadone in oil.  

PubMed

The unique anatomical arrangement of blood vessels and sinuses in the human skull and the brain, the prevalence of a high density of skin appendages in the scalp, extracranial vessels of the scalp communicating with the brain via emissary veins and most importantly, the way that the scalp is used in Ayurvedic medical system in treating diseases associated with the brain show that a drug could be transcranially delivered and targeted to the brain through the scalp. The present study was to investigate by measuring the antinociceptive effect on rats whether the opioid analgesic methadone could be delivered and targeted to the brain by transcranial delivery route. A non aqueous solution of methadone base in sesame oil was used for the application on the scalp. Animal studies were carried out using six groups of male rats consisting of group 1, the oral control treated with distilled water 1 ml; group 2, the oral positive control treated with methadone hydrochloride solution 316.5 mug/ml; group 3, the negative control treated transcranially with the blank sesame oil 0.2 ml and three test groups 4, 5 and 6 treated with three different dose levels of the transcranial oil formulation of methadone base, 41.6 mug/0.2 ml, 104 mug/0.2 ml and 208 mug/0.2 ml, respectively. The antinociceptive effects were examined by subjecting the rats to the hot plate and tail flick tests. The two higher concentrations of the three transcranial methadone formulations yielded response vs time curves showing nearly equal maximum antinociceptive effects similar to that of the oral positive control. Maximum analgesic effect after transcranial administration was observed between 1st and 2nd h and declined up to 6th hour. The results indicate that the transcranial brain targeted delivery of methadone base in the form of an oil based non aqueous solution results in statistically significant antinociceptive effects under experimental conditions. Therefore, it is possible to deliver central nervous system drugs through the proposed transcranial route when suitably formulated. PMID:20490292

Pathirana, W; Abhayawardhana, P; Kariyawasam, H; Ratnasooriya, W D

2009-05-01

174

Magnetically responsive microparticles for targeted drug and radionuclide delivery.  

SciTech Connect

We are currently investigating the use of magnetic particles--polymeric-based spheres containing dispersed magnetic nanocrystalline phases--for the precise delivery of drugs via the human vasculature. According to this review, meticulously prepared magnetic drug targeting holds promise as a safe and effective method of delivering drugs to specific organ, tissue or cellular targets. We have critically examined the wide range of approaches in the design and implementation of magnetic-particle-based drug delivery systems to date, including magnetic particle preparation, drug encapsulation, biostability, biocompatibility, toxicity, magnetic field designs, and clinical trials. However, we strongly believe that there are several limitations with past developments that need to be addressed to enable significant strides in the field. First, particle size has to be carefully chosen. Micrometer-sized magnetic particles are better attracted over a distance than nanometer sized magnetic particles by a constant magnetic field gradient, and particle sizes up to 1 {micro}m show a much better accumulation with no apparent side effects in small animal models, since the smallest blood vessels have an inner diameter of 5-7 {micro}m. Nanometer-sized particles <70 nm will accumulate in organ fenestrations despite an effective surface stabilizer. To be suitable for future human applications, our experimental approach synthesizes the magnetic drug carrier according to specific predefined outcome metrics: monodisperse population in a size range of 100 nm to 1.0 {micro}m, non-toxic, with appropriate magnetic properties, and demonstrating successful in vitro and in vivo tests. Another important variable offering possible improvement is surface polarity, which is expected to prolong particle half-life in circulation and modify biodistribution and stability of drugs in the body. The molecules in the blood that are responsible for enhancing the uptake of particles by the reticuloendothelial system (RES) prefer to associate with hydrophobic surfaces. Accordingly, we will tackle this challenge by modifying the particles with hydrophilic coatings such as PEG or poloxamer (co-polymers containing hydrophobic polyoxypropylene segments and repetitive polyoxyethylene hydrophilic groups), which have a proven ability to mask recognition by the RES. Modeling is needed to help optimize the performance of targeted magnetic-particle delivery, enhance its medicinal value, and expedite its medical application. To this end, scientists at Argonne National Laboratory, working with The University of Chicago and Cleveland Clinic Hospital, are working on an effective magnetic drug targeting system based on custom magnetic field designs coupled to a three-dimensional imaging platform that addresses all associated physical and theoretical problems. Furthermore, while our clinical trial results are encouraging with regard to the tolerance and applicability of the system, more improvements must be made with respect to future study designs and systems being used. Given the technical hurdles in developing this potentially important technology, we believe we have made great progress and that we have a strong developmental plan.

Kaminski, M. D.; Ghebremeskel, A. N.; Nunez, L.; Kasza, K. E.; Chang, F.; Chien, T.-H.; Fisher, P. F.; Eastman, J. A.; Rosengart, A. J.; McDonald, L.; Xie, Y.; Johns, L.; Pytel, P.; Hafeli, U. O.

2004-02-16

175

Targeted Spinal Cord Therapeutics Delivery: Stabilized Platform and Microelectrode Recording Guidance Validation  

Microsoft Academic Search

Background\\/Aims: No validated delivery technique exists for accurate, reproducible delivery of biological therapies to discrete spinal cord targets. To address this unmet need, we have constructed a stabilized platform capable of supporting physiologic mapping, through microelectrode recording, and cellular or viral payload delivery to the ventral horn. Methods: A porcine animal model (n = 7) has been chosen based upon

Jonathan Riley; John Butler; Kenneth B. Baker; Shearwood McClelland III; Qingshan Teng; Jun Yang; Mary Garrity-Moses; Thais Federici; Nicholas M. Boulis

2008-01-01

176

Physical blends of starch graft copolymers as matrices for colon targeting drug delivery systems  

Microsoft Academic Search

Colon targeting drug delivery systems have attracted many researchers due to the distinct advantages they present such as near neutral pH, longer transit time and reduced enzymatic activity. Moreover, in recent studies, colon specific drug delivery systems are gaining importance for use in the treatment of local pathologies of the colon and also for the systemic delivery of protein and

I. Silva; M. Gurruchaga; I. Goñi

2009-01-01

177

Colon Targeted Drug Delivery Systems: A Review on Primary and Novel Approaches  

Microsoft Academic Search

The colon is a site where both local and systemic delivery of drugs can take place. Local delivery allows topical treatment of inflammatory bowel disease. However, treatment can be made effective if the drugs can be targeted directly into the colon, thereby reducing the systemic side effects. This review, mainly compares the primary approaches for CDDS (Colon Specific Drug Delivery)

Anil K. Philip; Betty Philip

2010-01-01

178

Advances in lipid nanodispersions for parenteral drug delivery and targeting.  

PubMed

Parenteral formulations, particularly intravascular ones, offer a unique opportunity for direct access to the bloodstream and rapid onset of drug action as well as targeting to specific organ and tissue sites. Triglyceride emulsions, liposomes and micellar solutions have been traditionally used to accomplish these tasks and there are several products on the market using these lipid formulations. The broader application of these lipid systems in parenteral drug delivery, however, particularly with new chemical entities, has been limited due primarily to the following reasons: a) only a small number of parenteral lipid excipients are approved, b) there is increasing number of drugs that are partially or not soluble in conventional oils and other lipid solvents, and c) the ongoing requirement for site-specific targeting and controlled drug release. Thus, there is growing need to expand the array of targetable lipid-based systems to deliver a wide variety of drugs and produce stable formulations which can be easily manufactured in a sterile form, are cost-effective and at least as safe and efficacious as the earlier developed systems. These advanced parenteral lipid-based systems are at various stages of preclinical and clinical development which include nanoemulsions, nanosuspensions and polymeric phospholipid micelles. This review article will showcase these parenteral lipid nanosystems and discuss advances in relation to formulation development, processing and manufacturing, and stability assessment. Factors controlling drug encapsulation and release and in vivo biodistribution will be emphasized along with in vitro/in vivo toxicity and efficacy case studies. Emerging lipid excipients and increasing applications of injectable lipid nanocarriers in cancer chemotherapy and other disease indications will be highlighted and in vitro/in vivo case studies will be presented. As these new parenteral lipid systems advance through the clinic and product launch, their therapeutic utility and value will certainly expand. PMID:18096269

Constantinides, Panayiotis P; Chaubal, Mahesh V; Shorr, Robert

2007-11-06

179

Chimeric aptamers in cancer cell-targeted drug delivery  

PubMed Central

Aptamers are single-stranded structured oligonucleotides (DNA or RNA) that can bind to a wide range of targets ("apatopes") with high affinity and specificity. These nucleic acid ligands, generated from pools of random-sequence by an in vitro selection process referred to as systematic evolution of ligands by exponential enrichment (SELEX), have now been identified as excellent tools for chemical biology, therapeutic delivery, diagnosis, research, and monitoring therapy in real-time imaging. Today, aptamers represent an interesting class of modern Pharmaceuticals which with their low immunogenic potential mimic extend many of the properties of monoclonal antibodies in diagnostics, research, and therapeutics. More recently, chimeric aptamer approach employing many different possible types of chimerization strategies has generated more stable and efficient chimeric aptamers with aptamer-aptamer, aptamer-nonaptamer biomacromolecules (siRNAs, proteins) and aptamer-nanoparticle chimeras. These chimeric aptamers when conjugated with various biomacromolecules like locked nucleic acid (LNA) to potentiate their stability, biodistribution, and targeting efficiency, have facilitated the accurate targeting in preclinical trials. We developed LNA-aptamer (anti-nucleolin and EpCAM) complexes which were loaded in iron-saturated bovine lactofeerin (Fe-blf)-coated dopamine modified surface of superparamagnetic iron oxide (Fe3O4) nanoparticles (SPIONs). This complex was used to deliver the specific aptamers in tumor cells in a co-culture model of normal and cancer cells. This review focuses on the chimeric aptamers, currently in development that are likely to find future practical applications in concert with other therapeutic molecules and modalities.

Kanwar, Jagat R; Roy, Kislay; Kanwar, Rupinder K

2011-01-01

180

Mannosylated biodegradable polyethyleneimine for targeted DNA delivery to dendritic cells  

PubMed Central

Background To establish a potential gene-delivery system with the ability to deliver plasmid DNA to dendritic cells (DCs) more efficiently and specifically, we designed and synthesized a low-molecular-weight polyethyleneimine and triethyleneglycol polymer (PEI–TEG) and a series of its mannosylated derivatives. Methods PEI–TEG was synthesized from PEI2000 and PEI600 with TEG as the cross-linker. PEI–TEG was then linked to mannose via a phenylisothiocyanate bridge to obtain man-PEI–TEG conjugates. The DNA conveyance abilities of PEI–TEG, man-PEI–TEG, as well as control PEI25k were evaluated by measuring their zeta potential, particle size, and DNA-binding abilities. The in vitro cytotoxicity, cell uptake, and transfection efficiency of these PEI/DNA complexes were examined on the DC2.4 cell line. Finally, a maturation experiment evaluated the effect of costimulatory molecules CD40, CD80, and CD86 on murine bone marrow-derived DCs (BMDCs) using flow cytometry. Results PEI–TEG and man-PEI–TEG were successfully synthesized and were shown to retain the excellent properties of PEI25k for condensing DNA. Compared with PEI–TEG as well as PEI25k, the man-PEI–TEG had less cytotoxicity and performed better in both cellular uptake and transfection assays in vitro. The results of the maturation experiment showed that all the PEI/DNA complexes induced an adequate upregulation of surface markers for DC maturation. Conclusion These results demonstrated that man-PEI–TEG can be employed as a DC-targeting gene-delivery system.

Sun, Xun; Chen, Simu; Han, Jianfeng; Zhang, Zhirong

2012-01-01

181

A DNA nanocapsule with aptamer-controlled open-closure function for targeted delivery  

PubMed Central

A DNA capsule fitted with aptamer controlled target sensing has been “woven” using a 7308-base single-stranded DNA “thread” and 196 staple oligonucleotides. The capsule enables logic-gated molecular cargo delivery to targeted cell surfaces.

2012-01-01

182

Electrospun Nanofibers of Guar Galactomannan for Targeted Drug Delivery  

NASA Astrophysics Data System (ADS)

Guar galactomannan is a biodegradable polysaccharide used widely in the food industry but also in the cosmetics, pharmaceutical, oil drilling, textile and paper industries. Guar consists of a mannose backbone and galactose side groups that are both susceptible to enzyme degradation, a unique property that can be explored for targeted drug delivery especially since those enzymes are naturally secreted by the microflora in human colon. The present study can be divided into three parts. In the first part, we discuss ways to modify guar to produce nanofibers by electrospinning, a process that involves the application of an electric field to a polymer solution or melt to facilitate production of fibers in the sub-micron range. Nanofibers are currently being explored as the next generation of drug carriers due to its many advantages, none more important than the fact that nanofibers are on a size scale that is a fraction of a hair's width and have large surface-to-volume ratio. The incorporation and controlled release of nano-sized drugs is one way in which nanofibers are being utilized in drug delivery. In the second part of the study, we explore various methods to crosslink guar nanofibers as a means to promote water-resistance in a potential drug carrier. The scope and utility of water-resistant guar nanofibers can only be fully appreciated when subsequent drug release studies are carried out. To that end, the third part of our study focuses on understanding the kinetics and diffusion mechanisms of a model drug, Rhodamine B, through moderately-swelling (crosslinked) hydrogel nanofibers in comparison to rapidly-swelling (non-crosslinked) nanofibers. Along the way, our investigations led us to a novel electrospinning set-up that has a unique collector designed to capture aligned nanofibers. These aligned nanofiber bundles can then be twisted to hold them together like yarn. From a practical standpoint, these yarns are advantageous because they come freely suspended and without any attached support. As composites of aligned nanofibers, yarns potentially combine the inherent advantages of nanofibers with the strength and pliability of larger sized fibers. As such, we became interested in exploring the potential of nanofiber yarns as drug carriers. Our study evolved to accommodate comparative studies between the behavior of traditional nonwoven mats and nanofiber yarns. Throughout the process, we sought to answer the bigger question: Can guar galactomannan nanofibers be used as a new biodegradable platform for drug delivery?

Chu, Hsiao Mei Annie

183

Targeting blood-brain barrier sphingolipid signaling reduces basal P-glycoprotein activity and improves drug delivery to the brain.  

PubMed

P-glycoprotein, an ATP-driven drug efflux pump, is a major obstacle to the delivery of small-molecule drugs across the blood-brain barrier and into the CNS. Here we test a unique signaling-based strategy to overcome this obstacle. We used a confocal microscopy-based assay with isolated rat brain capillaries to map a signaling pathway that within minutes abolishes P-glycoprotein transport activity without altering transporter protein expression or tight junction permeability. This pathway encompasses elements of proinflammatory- (TNF-?) and sphingolipid-based signaling. Critical to this pathway was signaling through sphingosine-1-phosphate receptor 1 (S1PR1). In brain capillaries, S1P acted through S1PR1 to rapidly and reversibly reduce P-glycoprotein transport activity. Sphingosine reduced transport by a sphingosine kinase-dependent mechanism. Importantly, fingolimod (FTY720), a S1P analog recently approved for treatment of multiple sclerosis, also rapidly reduced P-glycoprotein activity; similar effects were found with the active, phosphorylated metabolite (FTY720P). We validated these findings in vivo using in situ brain perfusion in rats. Administration of S1P, FTY720, or FTY729P increased brain uptake of three radiolabeled P-glycoprotein substrates, (3)H-verapamil (threefold increase), (3)H-loperamide (fivefold increase), and (3)H-paclitaxel (fivefold increase); blocking S1PR1 abolished this effect. Tight junctional permeability, measured as brain (14)C-sucrose accumulation, was not altered. Therefore, targeting signaling through S1PR1 at the blood-brain barrier with the sphingolipid-based drugs, FTY720 or FTY720P, can rapidly and reversibly reduce basal P-glycoprotein activity and thus improve delivery of small-molecule therapeutics to the brain. PMID:22949658

Cannon, Ronald E; Peart, John C; Hawkins, Brian T; Campos, Christopher R; Miller, David S

2012-09-04

184

Targeted nonviral delivery vehicles to neural progenitor cells in the mouse subventricular zone  

Microsoft Academic Search

Targeted gene therapy can potentially minimize undesirable off-target toxicity due to specific delivery. Neuron-specific gene delivery in the central nervous system is challenging because neurons are non-dividing and also outnumbered by glial cells. One approach is to transfect dividing neural stem and progenitor cells (NSCs and NPCs, respectively). In this work, we demonstrate cell-specific gene delivery to NPCs in the

Ester J. Kwon; Jurate Lasiene; Berit E. Jacobson; In-Kyu Park; Philip J. Horner; Suzie H. Pun

2010-01-01

185

Recent developments in carbohydrate-decorated targeted drug/gene delivery.  

PubMed

Targeted delivery of a drug or gene to its site of action has clear therapeutic advantages by maximizing its therapeutic efficiency and minimizing its systemic toxicity. Generally, targeted drug or gene delivery is performed by loading a macromolecular carrier with an appropriate drug or gene, and by targeting the drug/gene carrier to specific cell or tissue with the help of specific targeting ligand. The emergence of glycobiology, glycotechnology, and glycomics and their continual adaptation by pharmaceutical scientists have opened exciting avenue of medicinal applications of carbohydrates. Among them, the biocompatibility and specific receptor recognition ability confer the ability of carbohydrates as potential targeting ligands for targeted drug and gene delivery applications. This review summarizes recent progress of carbohydrate-decorated targeted drug/gene delivery applications. PMID:19626595

Zhang, Hailong; Ma, Yong; Sun, Xue-Long

2010-03-01

186

Mucoadhesive platforms for targeted delivery to the colon.  

PubMed

A novel platform system, comprising a mucoadhesive core and a rapid release carrier, was designed for targeted drug delivery to the colon. Prednisolone pellets containing different carbomers, including Carbopol 971P, Carbopol 974P and Polycarbophil AA-1, with or without organic acids, were produced by extrusion-spheronization. Mucoadhesive pellets were coated with a new enteric double-coating system, which dissolves at pH 7. This system comprises an inner layer of partially neutralized Eudragit S and buffer salt and an outer coating of standard Eudragit S. A single layer of standard Eudragit S was also applied for comparison purposes. Dissolution of the coated pellets was assessed in USP II apparatus in 0.1N HCl followed by Krebs bicarbonate buffer pH 7.4. Visualization of the coating dissolution process was performed by confocal laser scanning microscopy using fluorescent markers in both layers. The mucoadhesive properties of uncoated, single-coated and-double coated pellets were evaluated ex vivo on porcine colonic mucosa. Mucoadhesive pellets coated with a single layer of Eudragit S release its cargo after a lag time of 120 min in Krebs buffer. In contrast, drug release from the double-coated mucoadhesive pellets was significantly accelerated, starting at 75 min. In addition, the mucoadhesive properties of the core of the double coated pellets were higher than those from single-coated pellets after the core had been exposed to the buffer medium. This novel platform technology has the potential to target the colon and overcome the variability in transit and harmonize drug release and bioavailability. PMID:21856393

Varum, Felipe J O; Veiga, Francisco; Sousa, João S; Basit, Abdul W

2011-08-11

187

Targeting Drug Delivery to the Lungs by Inhalation  

PubMed Central

Most drugs targeted to the respiratory tract are used for their local action. For example, ephidrine for nasal decongestion, beta-2 agonists for bronchodilatation, and inhaled steroids to suppress the inflammation seen in asthmatic airways. Since the drug is delivered directly to its required site, only a small quantity is needed for an adequate therapeutic response, and consequently there is a low incidence of systemic side effects compared with oral or intravenous administration. More recently, it has become apparent that the lining of the respiratory tract, from nasal mucosa to airways and alveoli, may be used for the absorption of a drug for its systemic effect. This route of administration may be particularly attractive if it avoids the metabolic destruction encountered when some drugs are administered by alternative routes (for instance, peptides and proteins are rapidly destroyed by peptidases when Oven by the oral route). If there is a lack ofclinical response to an aerosolized drug, it is important to question whether the drug has failed or whether delivery to the site of action is inadequate. To deliver therapeutic agents by inhalation to the lower respiratory tract, inhaled drug particles must have appropriate aerodynamic characteristics. In addition, the anatomy and pathophysiology of the patient's respiratory tract, mode of inhalation through the inhaler, and the characteristics of the inhalational device itself, may significantly affect drug deposition.

O'Callaghan, C.

1994-01-01

188

Intranasal nanoemulsion based brain targeting drug delivery system of risperidone.  

PubMed

The objective of investigation was to prepare nanoemulsion containing risperidone (RSP) to accomplish the delivery of drug to the brain via nose. Risperidone nanoemulsion (RNE) and mucoadhesive nanoemulsion (RMNE) were characterized for drug content, pH, percentage transmittance, globule size and zeta potential. Biodistribution of RNE, RMNE, and risperidone solution (RS) in the brain and blood of Swiss albino rats following intranasal (i.n.) and intravenous (i.v.) administration was examined using optimized technetium labeled ((99m)Tc-labeled) RSP formulations. Gamma scintigraphy imaging of rat brain following i.v. and i.n. administrations were performed to ascertain the localization of drug in brain. The brain/blood uptake ratio of 0.617, 0.754, 0.948, and 0.054 for RS (i.n.), RNE (i.n.), RMNE (i.n.), and RNE (i.v.), respectively, at 0.5h are indicative of direct nose to brain transport bypassing the blood-brain barrier. Higher drug transport efficiency (DTE%) and direct nose to brain drug transport (direct transport percentage, DTP%) for mucoadhesive nanoemulsions indicated more effective and best brain targeting of RSP amongst the prepared nanoemulsions. Studies conclusively demonstrated rapid and larger extent of transport of RSP by RMNE (i.n.) when compared to RS (i.n.), RNE (i.n.) and RNE (i.v.) into the rat brain. PMID:18455333

Kumar, Mukesh; Misra, Ambikanandan; Babbar, A K; Mishra, A K; Mishra, Puspa; Pathak, Kamla

2008-03-27

189

(-)-Epigallocatechin gallate sensitizes breast cancer cells to paclitaxel in a murine model of breast carcinoma  

Microsoft Academic Search

INTRODUCTION: Paclitaxel (Taxol®) is a microtubule-targeted agent that is widely used for cancer treatment. However, resistance to paclitaxel is frequently encountered in the clinic. There is increasing interest in identifying compounds that may increase the sensitivity to conventional chemotherapeutic agents. In this study, we investigated whether green tea polyphenol (-)-epigallocatechin gallate (EGCG) could sensitize breast carcinoma to paclitaxel in vivo.

Ting Luo; Jiao Wang; Yancun Yin; Hui Hua; Jing Jing; Xiangming Sun; Minjing Li; You Zhang; Yangfu Jiang

2010-01-01

190

Characterization, pharmacokinetics and disposition of novel nanoscale preparations of paclitaxel.  

PubMed

Polymeric nanoparticles (NPs) have great potential application in achieving targeted delivery of anticancer drugs. Paclitaxel (PTX) loaded NPs were developed using biodegradable methoxy poly (ethylene glycol)-poly (?-caprolactone) (MPEG-PCL) diblock copolymer by solid dispersion technique without toxic organic solvent. The lyophilized powder has been stored at room temperature for more than six months and still unchanged. PTX-loaded MPEG-PCL nanoparticles (PTX-NPs) displayed that the highest drug loading of PTX was about 25.6% and entrapment efficiency was over 98%, and the optimized average diameter and polydispersity index (PDI) were about 27.6 ± 0.1 nm and 0.05, respectively. Moreover, experimental results shown PTX-NPs had sustained-release effects and its curve fitting followed the Higuchi model. The maximum tolerated dose (MTD) of PTX-NPs after single dose in Balb/c mice was above 80 mg PTX/kg body weight (b.w), which was 2.6-fold higher than that of Taxol(®) (30 mg PTX/kg b.w). The levels of PTX administrated PTX-NPs had obvious distinction to Taxol(®) in plasma, liver, spleen, kidneys, lungs, heart and tumor. Especially, the concentration of PTX in tumor administrated PTX-NPs was higher than administration of Taxol(®). All results suggested that we had contrived a simple, biodegradable, effective and controllable drug delivery system for paclitaxel. PMID:21596124

Wang, Cheng; Wang, Yingjing; Wang, Yujun; Fan, Min; Luo, Feng; Qian, Zhiyong

2011-05-10

191

Targeted inhibition of phosphatidyl inositol-3-kinase p110?, but not p110?, enhances apoptosis and sensitivity to paclitaxel in chemoresistant ovarian cancers.  

PubMed

The phosphatidylinositol 3-kinase (PI3K) pathway is one of the critical signaling cascades playing important roles in the chemoresistance of human cancer cells, including ovarian cancer. In this study, we investigated the potential of targeting the PI3K p110?-isoform as a novel approach to overcome the chemoresistance in ovarian cancer. The effects on apoptosis, cell viability, proliferation and migration in chemoresistant ovarian cancer cell were determined following targeted p110? inhibition by small interfering RNA (siRNA). Seven paclitaxel (PTX)-resistant sublines (SKpacs and A2780pac) were produced from SKOV3 and A2780 ovarian cancer cell lines. We, first, evaluated the expression of PI3K p110 isoforms in chemosensitive and chemoresistant ovarian cancer cell lines and patient specimens, and found that p110?-isoform was significantly overexpressed both in a panel of ovarian cancer samples, and in PTX-resistant sublines compared with their parent cell lines. RNA interference-mediated p110? silencing augmented PTX-mediated apoptosis (31.15 ± 13.88 %) and reduced cell viability (67 %) in PTX-resistant cells, whereas targeting p110? did not show a significant change in cell viability and apoptosis. In addition, p110? silencing impaired cell proliferation (60 %) in PTX-resistant SKpac cells. We also found the combined treatment group with p110? siRNA and PTX showed a significant inhibition of tumor growth of SKpac cells compared to the PTX-only treated group in a xenograft nude mouse model. Thus, the siRNA-mediated silencing of PI3K p110? resensitizes PTX-resistant ovarian cancer cells, and may be a useful therapeutic strategy for PTX-resistant ovarian cancers. PMID:23371322

Jeong, Ju-yeon; Kim, Kyung-Sul; Moon, Ji-Sook; Song, Ji-ae; Choi, Sung-ho; Kim, Kwang-il; Kim, Tae-Heon; An, Hee-Jung

2013-04-01

192

Construction of paclitaxel-loaded poly (2-hydroxyethyl methacrylate)-g-poly (lactide)-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine copolymer nanoparticle delivery system and evaluation of its anticancer activity  

PubMed Central

Background There is an urgent need to develop drug-loaded biocompatible nanoscale packages with improved therapeutic efficacy for effective clinical treatment. To address this need, a novel poly (2-hydroxyethyl methacrylate)-poly (lactide)-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine [PHEMA-g-(PLA-DPPE)] copolymer was designed and synthesized to enable these nanoparticles to be pH responsive under pathological conditions. Methods The structural properties and thermal stability of the copolymer was measured and confirmed by Fourier transform infrared spectroscopy, nuclear magnetic resonance, and thermogravimetric analysis. In order to evaluate its feasibility as a drug carrier, paclitaxel-loaded PHEMA-g-(PLA-DPPE) nanoparticles were prepared using the emulsion-solvent evaporation method. Results The PHEMA-g-(PLA-DPPE) nanoparticles could be efficiently loaded with paclitaxel and controlled to release the drug gradually and effectively. In vitro release experiments demonstrated that drug release was faster at pH 5.0 than at pH 7.4. The anticancer activity of the PHEMA-g-(PLA-DPPE) nanoparticles was measured in breast cancer MCF-7 cells in vivo and in vitro. In comparison with the free drug, the paclitaxel-loaded PHEMA-g-(PLA-DPPE) nanoparticles could induce more significant tumor regression. Conclusion This study indicates that PHEMA-g-(PLA-DPPE) nanoparticles are promising carriers for hydrophobic drugs. This system can passively target cancer tissue and release drugs in a controllable manner, as determined by the pH value of the area in which the drug accumulates.

Ma, Xiaowei; Wang, Huan; Jin, Shubin; Wu, Yan; Liang, Xing-Jie

2012-01-01

193

Colon Targeted Drug Delivery Systems: A Review on Primary and Novel Approaches  

PubMed Central

The colon is a site where both local and systemic delivery of drugs can take place. Local delivery allows topical treatment of inflammatory bowel disease. However, treatment can be made effective if the drugs can be targeted directly into the colon, thereby reducing the systemic side effects. This review, mainly compares the primary approaches for CDDS (Colon Specific Drug Delivery) namely prodrugs, pH and time dependent systems, and microbially triggered systems, which achieved limited success and had limitations as compared with newer CDDS namely pressure controlled colonic delivery capsules, CODESTM, and osmotic controlled drug delivery which are unique in terms of achieving in vivo site specificity, and feasibility of manufacturing process.

Philip, Anil K.; Philip, Betty

2010-01-01

194

Src family kinases and paclitaxel sensitivity  

PubMed Central

Src-family Kinases (SFKs) participate in the regulation of proliferation, differentiation, apoptosis, autophagy, adhesion, migration, invasion and angiogenesis in normal and cancer cells. Abnormal expression of SFKs has been documented in cancers that arise in breast, colon, ovary, melanocyte, gastric mucosa, head and neck, pancreas, lung and brain. Targeting SFKs in cancer cells has been shown to be a promising therapeutic strategy in solid tumors, particularly in ovarian, colon and breast cancers. Paclitaxel is one of most widely used chemotherapeutic agents for the management of ovarian, breast, lung and head and neck cancers. As a microtubule-stabilizing agent, paclitaxel possesses both mitosis-dependent and mitosis-independent activities against cancer cells. A variety of mechanisms such as deregulation of P-glycoprotein, alteration of tubulin isotypes, alteration of microtubule-regulatory proteins, deregulation of apoptotic signaling pathways, mutation of tubulins and overexpression of copper transporters have been implicated in the development of primary or secondary resistance to paclitaxel. By affecting cancer cell survival, proliferation, autophagy, microtubule stability, motility, and/or angiogenesis, SFKs interact with mechanisms that regulate paclitaxel sensitivity. Inhibition of SFKs can potentiate the anti-tumor activity of paclitaxel by enhancing apoptosis, autophagy and microtubule stability. Based on pre-clinical observations, administration of SFK inhibitors in combination with paclitaxel could improve treatment for ovarian, breast, lung and head and neck cancers. Identification and validation of predictive biomarkers could also permit personalization of the therapy.

2011-01-01

195

Src family kinases and paclitaxel sensitivity.  

PubMed

Src-family Kinases (SFKs) participate in the regulation of proliferation, differentiation, apoptosis, autophagy, adhesion, migration, invasion and angiogenesis in normal and cancer cells. Abnormal expression of SFKs has been documented in cancers that arise in breast, colon, ovary, melanocyte, gastric mucosa, head and neck, pancreas, lung, and brain. Targeting SFKs in cancer cells has been shown to be a promising therapeutic strategy in solid tumors, particularly in ovarian, colon and breast cancers. Paclitaxel is one of most widely used chemotherapeutic agents for the management of ovarian, breast, lung and head/neck cancers. As a microtubule-stabilizing agent, paclitaxel possesses both mitosis-dependent and mitosis-independent activities against cancer cells. A variety of mechanisms such as deregulation of P-glycoprotein, alteration of tubulin isotypes, alteration of microtubule-regulatory proteins, deregulation of apoptotic signaling pathways, mutation of tubulins and overexpression of copper transporters have been implicated in the development of primary or secondary resistance to paclitaxel. By affecting cancer cell survival, proliferation, autophagy, microtubule stability, motility, and/or angiogenesis, SFKs interact with mechanisms that regulate paclitaxel sensitivity. Inhibition of SFKs can potentiate the anti-tumor activity of paclitaxel by enhancing apoptosis, autophagy and microtubule stability. Based on pre-clinical observations, administration of SFK inhibitors in combination with paclitaxel could improve treatment for ovarian, breast, lung and head/neck cancers. Identification and validation of predictive biomarkers could also permit personalization of the therapy. PMID:21646863

Le, Xiao-Feng; Bast, Robert C

2011-08-15

196

Targeted drug delivery using immunoconjugates: principles and applications.  

PubMed

Antibody-drug conjugates (also known as "immunoconjugates") have only recently entered the arsenal of anticancer drugs, but the number of undergoing clinical trials including them is ever increasing and most therapeutic antibodies are now patented including their potential immunoconjugate derivatives. They typically consist of three components: antibody, linker, and cytotoxin. An antibody or antibody fragment targeted to a tumor-associated antigen acts as a carrier for drug delivery and can be conjugated by cleavable or uncleavable linkers to a variety of effector molecules, either a drug, toxin, radioisotope, enzyme (the latter also used in Antibody-Directed Enzyme Prodrug Therapy), or to drug-containing liposomes or nanoparticles. In this review, we propose a general outline of the field, starting from the diagnostic and clinical applications of this class of molecules. Special attention will be devoted to the principles and issues in molecular design (choice of tumor-associated antigen, critical milestones in antibody development, available alternatives for linkers and effector molecule, and strategies for fusion proteins building) to the importance of antibody affinity modulation to optimize therapeutic effect and the potential of emerging alternative scaffolds. Most of the power of these molecules is to reach high concentrations in the tumor, relatively unaffecting normal cells, although one drawback lies in their short half-life. In this respect, modifications of immunoconjugates, which have shown to strongly influence pharmacokinetics, like glycosylation and PEGylation, will be discussed. Undergoing clinical trials and active patents will be analyzed and problems present in clinical use will be reported. PMID:21989410

Pasquetto, Maria Valentina; Vecchia, Luca; Covini, Daniele; Digilio, Rita; Scotti, Claudia

197

Disulfiram targets cancer stem-like cells and reverses resistance and cross-resistance in acquired paclitaxel-resistant triple-negative breast cancer cells.  

PubMed

Background:Triple-negative breast cancer (TNBC) has significantly worse prognosis. Acquired chemoresistance remains the major cause of therapeutic failure of TNBC. In clinic, the relapsed TNBC is commonly pan-resistant to various drugs with completely different resistant mechanisms. Investigation of the mechanisms and development of new drugs to target pan-chemoresistance will potentially improve the therapeutic outcomes of TNBC patients.Methods:In this study, 1-(4,5-Dimethylthiazol-2-yl)-3,5-diphenylformazan (MTT), combination index (CI)-isobologram, western blot, ALDEFLUOR analysis, clonogenic assay and immunocytochemistry were used.Results:The chemoresistant MDA-MB-231PAC10 cells are highly cross-resistant to paclitaxel (PAC), cisplatin (CDDP), docetaxel and doxorubicin. The MDA-MB-231PAC10 cells are quiescent with significantly longer doubling time (64.9 vs 31.7?h). This may be caused by high expression of p21(Waf1). The MDA-MB-231PAC10 cells express high aldehyde dehydrogenase (ALDH) activity and a panel of embryonic stem cell-related proteins, for example, Oct4, Sox2, Nanog and nuclealisation of HIF2? and NF-?Bp65. We have previously reported that disulfiram (DS), an antialcoholism drug, targets cancer stem cells (CSCs) and enhances cytotoxicity of anticancer drugs. Disulfiram abolished CSC characters and completely reversed PAC and CDDP resistance in MDA-MB-231PAC10 cells.Conclusion:Cancer stem cells may be responsible for acquired pan-chemoresistance. As a drug used in clinic, DS may be repurposed as a CSC inhibitor to reverse the acquired pan-chemoresistance. PMID:24008666

Liu, P; Kumar, I S; Brown, S; Kannappan, V; Tawari, P E; Tang, J Z; Jiang, W; Armesilla, A L; Darling, J L; Wang, W

2013-09-05

198

Epidermal growth factor receptor: Target for delivery and silencing  

Microsoft Academic Search

Epidermal growth factor receptor in cancer therapy Recently, cancer research has been able to identify molecular targets that are specific for (or highly expressed by) cancer cells. These molecular targets serve as models for the development of rationally designed anticancer drugs that target important mediators of tumour development. Also, some of these molecular targets have been explored for targeted drug

S. Oliveira

2008-01-01

199

Targeting Delivery of Chemotherapeutic Agents to Mammary Tumors.  

National Technical Information Service (NTIS)

Breast cancer is the second leading cause of cancer incidence and the leading cause of cancer mortality in women. Current chemotherapeutic treatments often have adverse effects primarily caused by the inefficient delivery and/or poor specificity of the co...

S. G. Brodie

2001-01-01

200

Synthesis and evaluation of airway targeted PLGA nanoparticles for drug delivery in obstructive lung diseases.  

PubMed

Chronic airway inflammation is a hallmark of chronic obstructive airway diseases, including asthma, COPD (chronic obstructive pulmonary disease), and CF (cystic fibrosis). It is also a major challenge in delivery and therapeutic efficacy of nano-based delivery systems in these chronic airway conditions as nanoparticle (NP) need to bypass airways defense mechanisms as we recently discussed. NPs which are capable of overcoming airways defense mechanisms should allow targeted drug delivery to disease cells. Over the last decade there has been increasing interest in development of targeted NPs for cancer but relatively little effort on designing novel systems for treating chronic inflammatory and obstructive airway conditions. Here we describe methods for preparing drug loaded multifunctional nanoparticles for targeted delivery to specific cell types in airways. The formulations and methods for selective drug delivery, discussed here are currently under preclinical development in our laboratory for treating chronic airway conditions such as COPD, CF, and asthma. PMID:22791443

Vij, Neeraj

2012-01-01

201

Targeted delivery of TLR ligands to human and mouse dendritic cells strongly enhances adjuvanticity  

Microsoft Academic Search

Effective vaccines consist of 2 components: immunodominant antigens and effective adjuvants. Whereas it has been demonstrated that targeted delivery of antigens to dendritic cells (DCs) improves vaccine efficacy, we report here that co-targeting of TLR ligands (TLRLs) to DCs strongly enhances adjuvanticity and immunity. We encapsulated ligands for intracellular TLRs within biodegradable nanoparticles coated with Abs recognizing DC-specific receptors. Targeted

P. J. Tacken; I. S. Zeelenberg; L. J. Cruz; M. A. van Hout-Kuijer; G. van de Glind; R. G. Fokkink; A. J. A. Lambeck; C. G. Figdor

2011-01-01

202

Development and in vitro validation of a targeted delivery vehicle for DNA vaccines  

Microsoft Academic Search

Usage of DNA vaccination has been limited by inefficient cellular expression of plasmid constructs used in DNA vaccines. We describe a novel system for enhancing delivery of DNA vaccine plasmids into cells and their nuclei. This delivery system uses recombinant reovirus type 3 ?1 attachment protein genetically modified with a nuclear localization sequence (?1-NLS) as a targeting ligand. Purified ?1-NLS

Silke S. Talsma; Julia E. Babensee; Niren Murthy; Ifor R. Williams

2006-01-01

203

Inhibitory Effect of Paclitaxel on Endothelial Cell Adhesion and Migration  

Microsoft Academic Search

The long-term success of percutaneous coronary interventions has been limited by restenosis. Therefore, local delivery of paclitaxel, an antiproliferative agent, using drug-eluting stents has been applied to prevent in-stent restenosis. However, paclitaxel not only inhibits smooth muscle cell proliferation, but also delays re-endothelialization of the damaged site, which may cause potentially life-threatening cardiovascular adverse events, especially late and very late

Hua Li; Li-jun Zhang; Bai-hua Chen; Xuan Zhou; Ke Su; Wen-tao Shi; Jun-zhu Wu; Hong Yu; Lei Wei

2010-01-01

204

Mesenchymal Stem Cell as Targeted-Delivery Vehicle in Breast Cancer.  

National Technical Information Service (NTIS)

Mesenchymal stem cells (MSCs) have been proposed to be cellular vehicles for the targeted delivery and local production of biological agents in tumors. In this proposal we will stably transfect mesenchymal stem cells with a lentiviral vector containing a ...

Z. Cheng

2010-01-01

205

Synergistic antitumor activity from two-stage delivery of targeted toxins and endosome-disrupting nanoparticles.  

PubMed

Plant-derived Type I toxins are candidate anticancer therapeutics requiring cytosolic delivery into tumor cells. We tested a concept for two-stage delivery, whereby tumor cells precoated with an antibody-targeted gelonin toxin were killed by exposure to endosome-disrupting polymer nanoparticles. Co-internalization of particles and tumor cell-bound gelonin led to cytosolic delivery and >50-fold enhancement of toxin efficacy. This approach allows the extreme potency of gelonin to be focused on tumors with significantly reduced potential for off-target toxicity. PMID:23444913

Su, Xingfang; Yang, Nicole; Wittrup, K Dane; Irvine, Darrell J

2013-03-11

206

Coupled Particulate and Continuum Model for Nanoparticle Targeted Delivery.  

PubMed

Prediction of nanoparticle (NP) distribution in a vasculature involves transport phenomena at various scales and is crucial for the evaluation of NP delivery efficiency. A combined particulate and continuum model is developed to model NP transport and delivery processes. In the particulate model ligand-receptor binding kinetics is coupled with Brownian dynamics to study NP binding on a microscale. An analytical formula is derived to link molecular level binding parameters to particulate level adhesion and detachment rates. The obtained NP adhesion rates are then coupled with a convection-diffusion-reaction model to study NP transport and delivery at macroscale. The binding results of the continuum model agree well with those from the particulate model. The effects of shear rate, particle size and vascular geometry on NP adhesion are investigated. Attachment rates predicted by the analytical formula also agree reasonably well with the experimental data reported in literature. The developed coupled model that links ligand-receptor binding dynamics to NP adhesion rate along with macroscale transport and delivery processes may serve as a faster evaluation and prediction tool to determine NP distribution in complex vascular networks. PMID:23729869

Tan, Jifu; Wang, Shunqiang; Yang, Jie; Liu, Yaling

2013-06-01

207

Long Circulating Lectin Conjugated Paclitaxel Loaded Magnetic Nanoparticles: A New Theranostic Avenue for Leukemia Therapy  

PubMed Central

Amongst all leukemias, Bcr-Abl positive chronic myelogenous leukemia (CML) confers resistance to native drug due to multi drug resistance and also resistance to p53 and fas ligand pathways. In the present study, we have investigated the efficacy of microtubule stabilizing paclitaxel loaded magnetic nanoparticles (pac-MNPs) to ascertain its cytotoxic effect on Bcr-Abl positive K562 cells. For active targeted therapy, pac-MNPs were functionalized with lectin glycoprotein which resulted in higher cellular uptake and lower IC50 value suggesting the efficacy of targeted delivery of paclitaxel. Both pac-MNPs and lectin conjugated pac-MNPs have a prolonged circulation time in serum suggesting increased bioavailability and therapeutics index of paclitaxel in vivo. Further, the molecular mechanism pertaining to pac-induced cytotoxicity was analyzed by studying the involvement of different apoptotic pathway proteins by immunoblotting and quantitative PCR. Our study revealed simultaneous activation of JNK pathway leading to Bcr-Abl instability and the extrinsic apoptotic pathway after pac-MNPs treatment in two Bcr-Abl positive cell lines. In addition, the MRI data suggested the potential application of MNPs as imaging agent. Thus our in vitro and in vivo results strongly suggested the pac-MNPs as a future prospective theranostic tool for leukemia therapy.

Singh, Abhalaxmi; Dilnawaz, Fahima; Sahoo, Sanjeeb Kumar

2011-01-01

208

Targeted nanoparticles with novel non-peptidic ligands for oral delivery.  

PubMed

Orally administered targeted nanoparticles have a large number of potential biomedical applications and display several putative advantages for oral drug delivery, such as the protection of fragile drugs or modification of drug pharmacokinetics. These advantages notwithstanding, oral drug delivery by nanoparticles remains challenging. The optimization of particle size and surface properties and targeting by ligand grafting have been shown to enhance nanoparticle transport across the intestinal epithelium. Here, different grafting strategies for non-peptidic ligands, e.g., peptidomimetics, lectin mimetics, sugars and vitamins, that are stable in the gastrointestinal tract are discussed. We demonstrate that the grafting of these non-peptidic ligands allows nanoparticles to be targeted to M cells, enterocytes, immune cells or L cells. We show that these grafted nanoparticles could be promising vehicles for oral vaccination by targeting M cells or for the delivery of therapeutic proteins. We suggest that targeting L cells could be useful for the treatment of type 2 diabetes or obesity. PMID:23454185

des Rieux, Anne; Pourcelle, Vincent; Cani, Patrice D; Marchand-Brynaert, Jacqueline; Préat, Véronique

2013-02-20

209

Battling with environments: drug delivery to target tissues with particles and functional biomaterials  

PubMed Central

Recent years have seen a growing interest in drug-delivery technology as an enabling tool for complicated pharmacological activities. At the same time, this field has faced as many ideas into clinical benefits. The Laboratory for Therapeutic Particles and Biomaterials Engineering at Purdue University (IN, USA) has striven to identify the current challenges in drug delivery and find solutions through the design of new drug-delivery systems. We develop new inhalable formulations for drug and gene delivery for cystic fibrosis patients, simple particle platforms for inhalable drug delivery, anion-resistant nonviral gene vectors, tumor-targeted nanoparticle systems, and hydrogel-based therapeutics. Through expanded collaborations with researchers in medicine and related disciplines, we strive to contribute to advancing the drug delivery field in a clinically relevant manner.

Yeo, Yoon

2011-01-01

210

A two-component drug delivery system using Her-2-targeting thermosensitive liposomes.  

PubMed

We report on a new method for enhancing the specificity of drug delivery for tumor cells, using thermosensitive immunoliposomes. The liposomes are conjugated to the antibody trastuzumab (Herceptin), which targets the human epidermal growth factor receptor 2 (Her-2), a cell membrane receptor overexpressed in many human cancers. Being thermosensitive, the liposomes only release their contents when heated slightly above body temperature, allowing for the possibility of tissue targeting through localized hyperthermia. Using self-quenching calcein, we demonstrate the release of liposome contents into cell endosomes after brief heating to 42 degrees C. To further increase targeting specificity, we incorporate the concept of a two-component delivery system that requires the interaction of two different liposomes within the same endosome for cytoplasmic delivery. Experimental evaluation of the technique using fluorescently labeled liposomes shows that a two-component delivery system, combined with intracellular disruption of liposomes by hyperthermia, significantly increases specificity for Her-2-overexpressing tumor cells. PMID:19089689

Kullberg, Max; Mann, Kristine; Owens, Jesse Lee

2009-02-01

211

Clusterin Interacts with Paclitaxel and Confer Paclitaxel Resistance in Ovarian Cancer12  

PubMed Central

Optimal debulking followed by chemotherapy is the standard treatment of managing late-stage ovarian cancer, but chemoresistance is still a major problem. In this study, we compared expression profiles of primary tumor tissue from five long-term (>8 years) and five short-term (<2 years) ovarian cancer survivors and identified clusterin as one of the genes that were significantly up-regulated in short-term survivors. We then evaluated the prognostic significance of clusterin and its possible correlation with chemoresistance in ovarian cancer by immunohistostaining of clusterin in 62 tumor samples from patients with stage III, high-grade serous ovarian cancer. After adjusting for debulking status and age, Cox regression analyses showed that high levels of clusterin expression correlate with poor survival (hazard ratio, 1.07; 95% confidence interval, 1.002–1.443; P = .04). We also investigated clusterin in paclitaxel resistance by modulating the endogenous clusterin expression in ovarian cancer cells and treating the cells with purified clusterin. Results indicate that high-clusterin-expressing ovarian cancer cells are more resistant to paclitaxel. Moreover, exposing ovarian cancer cells to exogenous clusterin increases cells' resistance to paclitaxel. Finally, using size exclusion chromatography and fluorescently labeled paclitaxel, we demonstrated that clusterin binds to paclitaxel. In summary, our findings suggest that high levels of clusterin expression increase paclitaxel resistance in ovarian cancer cells by physically binding to paclitaxel, which may prevent paclitaxel from interacting with microtubules to induce apoptosis. Thus, clusterin is a potential therapeutic target for enhancing chemoresponsiveness in patients with a high-level clusterin expression.

Park, Dong Choon; Yeo, Seung Geun; Wilson, Mark R; Yerbury, Justin J; Kwong, Joseph; Welch, William R; Choi, Yang Kyu; Birrer, Michael J; Mok, Samuel C; Wong, Kwong-Kwok

2008-01-01

212

A combinatorial approach for targeted delivery using small molecules and reversible masking to bypass nonspecific uptake in vivo  

Microsoft Academic Search

We have developed a multi-disciplinary approach combining molecular biology, delivery technology, combinatorial chemistry and reversible masking to create improved systemic, targeted delivery of plasmid DNA while avoiding nonspecific uptake in vivo. We initially used a well-characterized model targeting the asialolglycoprotein receptor in the liver. Using our bilamellar invaginated vesicle (BIV) liposomal delivery system with reversible masking, we increased expression in

Q Shi; A T Nguyen; Y Angell; D Deng; C-R Na; K Burgess; D D Roberts; F C Brunicardi; N S Templeton

2010-01-01

213

The use of microbubbles to target drug delivery  

Microsoft Academic Search

Ultrasound-mediated microbubbles destruction has been proposed as an innovative method for noninvasive delivering of drugs and genes to different tissues. Microbubbles are used to carry a drug or gene until a specific area of interest is reached, and then ultrasound is used to burst the microbubbles, causing site-specific delivery of the bioactive materials. Furthermore, the ability of albumin-coated microbubbles to

Jeane M Tsutsui; Feng Xie; Richard Thomas Porter

2004-01-01

214

Local delivery of nitric oxide: targeted delivery of therapeutics to bone and connective tissues  

PubMed Central

Non-invasive treatment of injuries and disorders affecting bones and connective tissue is a significant challenge facing the medical community. A treatment route that has recently been proposed is nitric oxide (NO) therapy. Nitric oxide plays several roles in physiology with many conditions lacking adequate levels of NO. As NO is a radical, localized delivery via NO donors is essential to promoting biological activity. Herein, we review current literature related to therapeutic NO delivery in the treatment of bone, skin and tendon repair.

Nichols, Scott P.; Storm, Wesley L.; Koh, Ahyeon; Schoenfisch, Mark H.

2012-01-01

215

Synthesis and characterization of cisplatin-loaded, EGFR-targeted biopolymer and in vitro evaluation for targeted delivery.  

PubMed

The design of smart targeted drug delivery systems that deliver drugs to specific cancer cells will give rise to cancer treatments with better efficacy and lower toxicity levels. We report the development and characterizations of maleimide-functionalized biopolymer (Mal-PGA-Asp) as an effective targeted drug delivery carrier synthesized from an amidation reaction between aspartylated PGA (PGA-Asp) and N-(maleimidohexanoyl)-ethylenediamine (NME). The epidermal growth factor receptor (EGFR) targeting peptide (TP13) was conjugated to Mal-PGA-Asp to obtain the targeting carrier (TP13-Mal-PGA-Asp). Cisplatin was finally loaded by complexation to form a biocompatible and tumor targeted therapeutic drug (TP13-Mal-PGA-Asp3-Pt). The resultant biopolymer with an average size 87 ± 28 nm showed a sustainable release profile with a half-maximal release time (t(1/2)) of approximately 15 h in physiological saline. Fluorescence imaging and flow cytometry analysis revealed that TP13 significantly enhanced the cellular uptake of TP13-Mal-PGA-Asp3-Pt in the human hepatoma cell line SMMC-7721. The IC(50) value demonstrated the superior anticancer activity of TP13-Mal-PGA-Asp3-Pt over PGA-Asp-Pt. Therefore, the newly developed drug carrier (TP13-Mal-PGA-Asp) obtained in this study may provide an efficient and targeted delivery of anticancer drugs, presenting a promising targeted chemotherapy in EGFR-positive cancers. PMID:22678850

Geng, Xu; Ye, Haifeng; Feng, Zhen; Lao, Xun; Zhang, Li; Huang, Jing; Wu, Zi-Rong

2012-06-07

216

Development of paclitaxel-TyroSpheres for topical skin treatment  

PubMed Central

A potential topical psoriasis therapy has been developed consisting of tyrosine-derived nanospheres (TyroSpheres) with encapsulated anti-proliferative paclitaxel. TyroSpheres provide enhancement of paclitaxel solubility (almost 4,000 times greater than PBS) by effective encapsulation and enable sustained, dose-controlled release over 72 hours under conditions mimicking skin permeation. TyroSpheres offer potential in the treatment of psoriasis, a disease resulting from over-proliferation of keratinocytes in the basal layer of the epidermis, by (a) enabling delivery of paclitaxel into the epidermis at concentrations >100 ng/cm2 of skin surface area and (b) enhancing the cytotoxicity of loaded paclitaxel to human keratinocytes (IC50 of paclitaxel-TyroSpheres was approximately 45% lower than that of free paclitaxel). TyroSpheres were incorporated into a gel-like viscous formulation to improve their flow characteristics with no impact on homogeneity, release or skin distribution of the payload. The findings reported here confirm that the TyroSpheres provide a platform for paclitaxel topical administration allowing skin drug localization and minimal systemic escape.

Kilfoyle, Brian E.; Sheihet, Larisa; Zhang, Zheng; Laohoo, Marissa; Kohn, Joachim; Michniak-Kohn, Bozena B.

2012-01-01

217

Laser-induced disruption of systemically administered liposomes for targeted drug delivery  

Microsoft Academic Search

Liposomal formulations of drugs have been shown to enhance drug efficacy by prolonging circulation time, increasing local concentration and reducing off-target effects. Controlled release from these formulations would increase their utility, and hyperthermia has been explored as a stimulus for targeted delivery of encapsulated drugs. Use of lasers as a thermal source could provide improved control over the release of

Mark A. Mackanos; Malika Larabi; Rajesh Shinde; Dmitrii M. Simanovskii; Samira Guccione; Christopher H. Contag

2009-01-01

218

Targeted drug delivery to ischemic heart with use of nanoparticulate carriers : Concepts, pitfalls and perspectives  

Microsoft Academic Search

Purpose – Clinical outcome in patients with ischemic heart disease can be significantly improved with the implementation of targeted drug delivery into the ischemic myocardium. The purpose of this paper is to review the data of recent literature and present original findings relevant to the problem of therapeutic heart targeting with use of nanoparticles. Design\\/methodology\\/approach – For literature review, a

Michael Galagudza; Dmitry Korolev; Dmitry Sonin; Viktor Postnov; Garry Papayan; Ivan Uskov; Anastasia Belozertseva; Eugene Shlyakhto

2010-01-01

219

Why I believe nanoparticles are crucial as a carrier for targeted drug delivery.  

PubMed

Nanoparticles are the only materials small enough to target cells in the body, and therefore are crucial to targeted drug delivery. Issues with the synthesis, consistency, and bioactivity of these molecules are still being addressed, but base on current proof of concept studies there is a reason to believe that the 'holy grail' of targeted drug delivery might someday be achieved using nanoparticle-based systems. WIREs Nanomed Nanobiotechnol 2013. doi: 10.1002/wnan.1226 Conflict of interest: The author has declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website. PMID:23633301

Baker, James R

2013-04-30

220

Synthesis of folate-functionalized RAFT polymers for targeted siRNA delivery  

PubMed Central

Receptor-mediated, cell-specific delivery of siRNA enables silencing of target genes in specific tissues, opening the door to powerful therapeutic options for a multitude of diseases. However, development of delivery systems capable of targeted and effective siRNA delivery typically requires multiple steps and use of sophisticated, orthogonal chemistries. Previously, we developed diblock copolymers consisting of dimethaminoethyl methacrylate-b-dimethylaminoethyl methacrylate-co-butyl methacrylate-copropylacrylic acid as potent siRNA delivery systems that protect siRNA from enzymatic degradation and enable its cytosolic delivery through pH-responsive, endosomolytic behavior.1,2 These architectures were polymerized using a living radical polymerization method, specifically reversible addition-fragmentation chain transfer (RAFT) polymerization, which employs a chain transfer agent (CTA) to modulate the rate of reaction, resulting in polymers with low polydispersity and telechelic chain ends reflecting the chemistry of the CTA. Here, we describe the straightforward, facile synthesis of a folate receptor-targeted diblock copolymer siRNA delivery system, as the folate receptor is an attractive target for tumor-selective therapies due to its overexpression in a number of cancers. Specifically, we detail the de novo synthesis of a folate-functionalized CTA, use the folate-CTA for controlled polymerizations of diblock copolymers, and demonstrate efficient, specific cellular folate receptor interaction and in vitro gene knockdown using the folate-functionalized polymer.

Srinivasan, Selvi; Shubin, Andrew D.; Stayton, Patrick S.

2011-01-01

221

Stent healing response following delivery of paclitaxel via durable polymeric matrix versus iopromide-based balloon coating in the familial hypercholesterolaemic swine model of coronary injury.  

PubMed

Aims: The routine use of paclitaxel-coated balloons (PCB) in combination with bare metal stents (BMS) in de novo coronary lesions has been questioned. In this study, we aimed to compare the vascular response of BMS implanted using a second-generation PCB (BMS+PCB) with the TAXUS stent (PES) and a BMS control (BMS) in the familial hypercholesterolaemic swine (FHS) model of coronary injury. Methods and results: A total of 17 stents (PES=6, BMS+PCB=6, and BMS=5) were implanted in the coronary territory of 10 FHS using a 20% overstretch injury ratio. Imaging evaluation (QCA and IVUS) was conducted in all animals at baseline and 28 days following stent implantation. Following terminal imaging all animals were euthanised and stented coronary segments harvested for histological evaluation. At 28 days, the lowest degree of percentage diameter stenosis by QCA was achieved by the PES (2.9±9%) followed by the BMS+PCB (9.5±16.4%) and the BMS group (25.65±18.7%, p<0.05). In histology, percentage area of stenosis (BMS+PCB=29.6±6.4% vs. PES=21.5±3.3% vs. BMS=55.2±12.9%; p<0.01) and neointimal thickness (BMS+PCB=0.26±0.1 mm vs. PES=0.21±0.1 mm vs. BMS=0.59±0.2 mm; p<0.01) were significantly reduced in both paclitaxel groups in comparison to BMS controls. Both BMS+PCB and BMS groups had higher endothelialisation scores (PES=1.50±0.9 vs. BMS+PCB=2.73±0.4 vs. BMS=3.00; p<0.05) and lower peri-strut inflammatory scores (PES=0.83±0.4 vs. BMS+PCB=0.20±0.2 vs. BMS=0.43±0.6, p<0.05) when compared to PES. Neointima maturity (PCB+BMS: 2.00 [2-2.4] vs. PES: 1.00 [0.3-1] vs. BMS: 3.00, p<0.05) and fibrin deposition (PCB+BMS: 1.40±0.3 vs. PES: 2.17±0.7 vs. BMS: 0.27±0.3, p<0.05) scores in PCB+BMS appeared to fall between the PES and the BMS ranges. Conclusions: In the FHS coronary injury model, BMS implantation using a PCB yields a degree of neointimal inhibition comparable to the PES. The BMS+PCB combination presented lower degrees of inflammation and fibrin deposition; however, signs of delayed healing were still present. PMID:23965356

Buszman, Piotr P; Tellez, Armando; Afari, Maxwell; Cheng, Yanping; Conditt, Gerard B; McGregor, Jennifer C; Milewski, Krzysztof; Stenoien, Mark; Kaluza, Greg L; Granada, Juan F

2013-08-22

222

Design of novel bioconjugates for targeted drug delivery  

Microsoft Academic Search

This paper summarizes recent work on the design and development of targeted polymeric bioconjugates based on N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers. Polymerizable antibody Fab’ fragment (MA-Fab’) has been developed and used in the preparation of targeted HPMA copolymer–mesochlorin e6 conjugates for the treatment of human ovarian carcinomas. The reactivity of the MA-Fab’ in copolymerization with HPMA depended on the length of the

Zheng-Rong Lu; Jane-Guo Shiah; Shinji Sakuma; Pavla Kope?ková; Jind?ich Kope?ek

2002-01-01

223

Conceptual design report for the University of Rochester cryogenic target delivery system  

SciTech Connect

The upgrade of the Omega laser at the University of Rochester's Laboratory for Laser Energetics (UR/LLE) will result in a need for large targets filled with D[sub 2] or Dt and maintained at cryogenic temperatures. This mandates a cryogenic target delivery system capable of filling, layering, characterizing and delivering cryogenic targets to the Omega Upgrade target chamber. The program goal is to design, construct, and test the entire target delivery system by June 1996. When completed (including an operational demonstration), the system will be shipped to Rochester for reassembly and commissioning in time for the Omega Upgrade cryogenic campaign, scheduled to start in 1998. General Atomics has been assigned the task of developing the conceptual design for the cryogenic target delivery system. Design and fabrication activities will be closely coordinated with the University of Rochester, Lawrence Livermore National laboratory (LLNL) and Los Alamos National Laboratory (LANL), drawing upon their knowledge base in fuel layering and cryogenic characterization. The development of a target delivery system for Omega could also benefit experiments at Lawrence Livermore National Laboratory and the other ICF Laboratories in that the same technologies could be applied to NOVA, the National Ignition Facility or the future Laboratory Microfusion Facility.

Fagaly, R.L.; Alexander, N.B.; Bourque, R.F.; Dahms, C.F.; Lindgren, J.R.; Miller, W.J. (General Atomics, San Diego, CA (United States)); Bittner, D.N.; Hendricks, C.D. (W.J. Schafer Associates, Livermore, CA (United States))

1993-05-01

224

Dendritic polymer-based nanodevices for targeted drug delivery applications  

NASA Astrophysics Data System (ADS)

Dendrimers and hyperbranched polymers are unimolecular micellar nanostructures, characterized by globular shape ( ˜ 20 nm) and large density of functional groups at periphery. The tailorable end groups make them ideal for conjugation with drugs, ligands, and imagining agents, making them an attractive molecular nanodevices for drug delivery. Compared to linear polymers and nanoparticles, these nanodevices enter cells rapidly, carrying drugs and delivering them inside cells. Performance of nanodevices prepared for asthma and cancer drug delivery will be discussed. Our conjugation procedure produced very high drug payloads. Dendritic polymer-drug conjugates were very effective in transporting methotrexate (a chemotherapy drug) into both sensitive (CCRF-CEM cell line) and resistant cell line (CEM-MTX). The conjugate nanodevice was 3 times more effective than free drug in the sensitive line, and 9 times more effective in the resistant cell line (based on IC50). The physics of cell entry and drug release from these nanodevices are being investigated. The conjugates appear to enter cells through endocytosis, with the rate of entry dependent on end-group, molecular weight, the pH of the medium, and the cancerous nature of the cells.

Kannan, R. M.; Kolhe, Parag; Gurdag, Sezen; Khandare, Jayant; Lieh-Lai, Mary

2004-03-01

225

Colon targeted drug delivery systems: a review on primary and novel approaches.  

PubMed

The colon is a site where both local and systemic delivery of drugs can take place. Local delivery allows topical treatment of inflammatory bowel disease. However, treatment can be made effective if the drugs can be targeted directly into the colon, thereby reducing the systemic side effects. This review, mainly compares the primary approaches for CDDS (Colon Specific Drug Delivery) namely prodrugs, pH and time dependent systems, and microbially triggered systems, which achieved limited success and had limitations as compared with newer CDDS namely pressure controlled colonic delivery capsules, CODESTM, and osmotic controlled drug delivery which are unique in terms of achieving in vivo site specificity, and feasibility of manufacturing process. PMID:22125706

Philip, Anil K; Philip, Betty

2010-04-01

226

Inhibition of neointimal proliferation after bare metal stent implantation with low-pressure drug delivery using a paclitaxel-coated balloon in porcine coronary arteries.  

PubMed

A variety of mechanical and laser-based methods remove or shift atherosclerotic plaques and reopen the artery to its original lumen. Subsequent treatment with drug-coated balloons (DCB) may smooth the vessel wall but does not require high-pressure inflation. We investigated the efficacy of paclitaxel-coated balloons inflated with only 2 atm after bare metal stent implantation in coronary arteries of 24 pigs. Angiography and histomorphometry was performed on day 28. DCB inflated with 2 atm caused similar reduction of late lumen loss (LLL) as high-pressure inflation with 12 atm (0.89 ± 0.58 vs. 0.72 ± 0.39 mm, p = 0.34). Both DCB treatments significantly (p < 0.01) reduced LLL versus uncoated balloons (1.50 ± 0.51 mm). Treatment with low-pressure DCB resulted in less maximal intimal thickness (0.45 ± 0.15 vs. 0.67 ± 0.25 mm) and neointimal area (2.93 ± 0.73 vs. 3.82 ± 1.27 mm(2)) than treatment with uncoated balloons (p < 0.05). In conclusion, low-pressure treatment with DCB was similarly effective as high-pressure treatment justifying clinical trials in vessels which will benefit from inhibition of neointimal proliferation but may not tolerate high inflation pressure. PMID:22237489

Cremers, Bodo; Kelsch, Bettina; Clever, Yvonne P; Hattangadi, Neil; Mahnkopf, Dirk; Speck, Ulrich; Taupitz, Matthias; Scheller, Bruno

2012-01-12

227

Primary cardiomyocyte-targeted bioreducible polymer for efficient gene delivery to the myocardium  

Microsoft Academic Search

A cardiomyocyte-targeted Fas siRNA delivery system was developed using primary cardiomyocyte (PCM) specific peptide-modified polymers with high transfection efficiency and low cytotoxicity. Primary cardiomyocyte (PCM) specific peptide, selected by phage display, was conjugated to bioreducible poly(cystamine bisacrylamide-diaminohexane, CBA-DAH) (PCD). The specificity of the PCM-modified polymer to cardiomyocytes was confirmed by competition study with free PCM ligand and by delivery to

Hye Y. Nam; Arlo McGinn; Pyung-Hwan Kim; Sung W. Kim; David A. Bull

2010-01-01

228

New development and application of ultrasound targeted microbubble destruction in gene therapy and drug delivery.  

PubMed

Ultrasound is a common used technique for clinical imaging. In recent years, with the advances in preparation technology of microbubbles and the innovations in ultrasound imaging, ultrasound is no longer confined to detection of tissue perfusion, but extends to specific ultrasound molecular imaging and target therapy gradually. With the development of research, ultrasound molecular imaging and target therapy have made great progresses. Targeted microbubbles for molecular imaging are achieved by binding target molecules, specific antibody or ligand to the surface of microbubbles to obtain specific imaging by attaching to target tissues. Meanwhile, it can also achieve targeting gene therapy or drug delivery by ultrasound targeted microbubble destruction (UTMD) mediating genes or drugs to specific target sites. UTMD has a number of advantages, such as target-specific, highly effective, non-invasivity, relatively low-cost and no radiation, and has broad application prospects, which is regarded as one hot spot in medical studies. We reviewed the new development and application of UTMD in gene therapy and drug delivery in this paper. With further development of technology and research, the gene or drug delivery system and related methods will be widely used in application and researches. PMID:23721204

Chen, Zhi-Yi; Yang, Feng; Lin, Yan; Zhang, Jin-Shan; Qiu, Ri-Xiang; Jiang, Lan; Zhou, Xing-Xing; Yu, Jiang-Xiu

2013-08-01

229

Preparation, characterization and in vitro cytotoxicity of paclitaxel-loaded sterically stabilized solid lipid nanoparticles.  

PubMed

In an effort to develop an alternative formulation of paclitaxel suitable for parenteral administration, paclitaxel-loaded sterically stabilized solid lipid nanoparticles (SLNs) were prepared, characterized and examined for in vitro cytotoxicity. The SLNs, comprising trimyristin (TM) as a solid lipid core and egg phosphatidylcholine and pegylated phospholipid as stabilizers, were prepared using a hot homogenization method. Regardless of paclitaxel loading, the particle sizes and zeta potentials of the prepared SLNs were around 200nm and -38mV, respectively, suggesting that they would be suitable as a parenteral formulation. Cryo-scanning electron microscopy showed that the SLNs were homogeneous and spherical in shape, while differential scanning calorimetry measurement of the melting peak revealed that the TM exists as a solid in our formulation. Paclitaxel was loaded to the solid cores at a w/w ratio of 6%. Gel column chromatography showed that paclitaxel co-eluted with the phospholipids, indicating that paclitaxel was incorporated in the SLNs. An in vitro drug release study showed that paclitaxel was released from the SLNs in a slow but time-dependent manner. Furthermore, treatment of the OVCAR-3 human ovarian cancer cell line and the MCF-7 breast cancer cell line with paclitaxel-loaded SLNs yielded cytotoxicities comparable to those of a commercially available Cremophor EL-based paclitaxel formulation. These results collectively suggest that our optimized SLN formulation may have a potential as alternative delivery system for parenteral administration of paclitaxel. PMID:17257668

Lee, Mi-Kyung; Lim, Soo-Jeong; Kim, Chong-Kook

2007-01-10

230

Choline transporter-targeting and co-delivery system for glioma therapy.  

PubMed

Combination of gene therapy and chemotherapy is a promising approach for glioma therapy. In this study, a co-delivery system of plasmid encoding human tumor necrosis factor-related apoptosis-inducing ligand (pORF-hTRAIL, Trail) and doxorubicin (DOX) has been simply constructed in two steps. Firstly, DOX was intercalated into Trail to form a stable complex. Secondly, DOX-Trail complex was condensed by Dendrigraft poly-l-lysine (DGL) to form a nanoscaled co-delivery system. Choline transporters are both expressed on blood-brain barrier (BBB) and glioma, Herein, a choline derivate with high choline transporter affinity was chosen as BBB and glioma dual targeting ligand. Choline-derivate modified co-delivery system showed higher cellular uptake efficiency and cytotoxicity than unmodified co-delivery system in U87 MG cells. In comparison with single medication or unmodified delivery system, Choline-derivate modified co-delivery system induced more apoptosis both in vitro and in vivo. The therapeutic efficacy on U87 MG bearing xenografts further confirmed the predominance of this dual targeting and co-delivery system. PMID:23993342

Li, Jianfeng; Guo, Yubo; Kuang, Yuyang; An, Sai; Ma, Haojun; Jiang, Chen

2013-08-28

231

Carboxymethyl starch and lecithin complex as matrix for targeted drug delivery: I. Monolithic Mesalamine forms for colon delivery.  

PubMed

For drugs expected to act locally in the colon, and for successful treatment, a delivery device is necessary, in order to limit the systemic absorption which decreases effectiveness and causes important side effects. Various delayed release systems are currently commercialized; most of them based on pH-dependent release which is sensitive to gastrointestinal pH variation. This study proposes a novel excipient for colon delivery. This new preparation consists in the complexation between carboxymethyl starch (CMS) and Lecithin (L). As opposed to existing excipients, the new complex is pH-independent, inexpensive, and easy to manufacture and allows a high drug loading. FTIR, X-ray, and SEM structural analysis all support the hypothesis of the formation of a complex. By minor variation of the excipient content within the tablet, it is possible to modulate the release time and delivery at specific sites of the gastrointestinal tract. This study opens the door to a new pH-independent delivery system for mesalamine targeted administration. Our novel formulation fits well with the posology of mesalamine, used in the treatment of Inflammatory Bowel Disease (IBD), which requires repeated administrations (1g orally four times a day) to maintain a good quality of life. PMID:23562535

Mihaela Friciu, Maria; Canh Le, Tien; Ispas-Szabo, Pompilia; Mateescu, Mircea Alexandru

2013-04-01

232

A polyvalent aptamer system for targeted drug delivery.  

PubMed

Poor efficacy and off-target systemic toxicity are major problems associated with current chemotherapeutic approaches to treat cancer. We developed a new form of polyvalent therapeutics that is composed of multiple aptamer units synthesized by rolling circle amplification and physically intercalated chemotherapy agents (termed as "Poly-Aptamer-Drug"). Using a leukemia cell-binding aptamer and doxorubicin as a model system, we have successfully constructed Poly-Aptamer-Drug systems and demonstrated that the Poly-Aptamer-Drug is significantly more effective than its monovalent counterpart in targeting and killing leukemia cells due to enhanced binding affinity (?40 fold greater) and cell internalization via multivalent effects. We anticipate that our Poly-Aptamer-Drug approach will yield new classes of tunable therapeutics that can be utilized to effectively target and treat cancers while minimizing the side effects of chemotherapy. PMID:24044994

Zhang, Zhiqing; Ali, M Monsur; Eckert, Mark A; Kang, Dong-Ku; Chen, Yih Yang; Sender, Leonard S; Fruman, David A; Zhao, Weian

2013-09-14

233

Transcriptional Profiling of Targets for Combination Therapy of Lung Carcinoma with Paclitaxel and Mitogen-activated Protein\\/Extracellular Signal-regulated Kinase Kinase Inhibitor1  

Microsoft Academic Search

A combination of paclitaxel (Taxol) and mitogen-activated protein\\/ extracellular signal-regulated kinase kinase (MEK\\/Erk) inhibitor repre- sents a rational new approach to chemotherapy. We performed Af- fymetrix microarray analysis to understand the global effects of this combination in lung carcinoma. Genes involved in cell cycle control, apoptosis, adhesion, proliferation, invasion, and metastasis were modu- lated. We observed similar patterns of gene

Debra J. Taxman; Jeffrey P. MacKeigan; Casey Clements; Daniel T. Bergstralh

2003-01-01

234

Targeted delivery of Tet1 peptide functionalized polymersomes to the rat cochlear nerve.  

PubMed

Polymersomes are nanosized vesicles formed from amphiphilic block copolymers, and have been identified as potential drug delivery vehicles to the inner ear. The aim of this study was to provide targeting to specific cells within the inner ear by functionalizing the polymersome surface with Tet1 peptide sequence. Tet1 peptide specifically binds to the trisialoganglioside clostridial toxin receptor on neurons and was expected to target the polymersomes toward the cochlear nerve. The Tet1 functionalized PEG-b-PCL polymersomes were administered using routine drug delivery routes: transtympanic injection and cochleostomy. Delivery via cochleostomy of Tet1 functionalized polymersomes resulted in cochlear nerve targeting; in contrast this was not seen after transtympanic injection. PMID:22403485

Zhang, Ya; Zhang, Weikai; Johnston, Alexander H; Newman, Tracey A; Pyykkö, Ilmari; Zou, Jing

2012-02-23

235

Exploring cell type-specific internalizing antibodies for targeted delivery of siRNA.  

PubMed

A major challenge to the development of therapeutic small interfering RNAs (siRNAs) is specific and efficient in vivo delivery to target cells. Recent studies suggest that cell type-specific gene silencing in vivo can be achieved by combining siRNAs with cell type-specific affinity ligands such as monoclonal antibodies. The antibody-directed siRNA complex enters target cells through receptor endocytosis and is subsequently released to the cytosol to specifically silence target gene expression through biologically conserved RNA interference (RNAi) pathways. Antibody fragments fused with a small basic nucleic-acid-binding protein and antibody fragment-directed nanoimmunoliposomes are two examples of effective delivery vehicles in vivo. The demonstrated specificity of in vivo gene silencing and the lack of nonspecific immune activation and systemic toxicity encourage further development of therapies based on cell type-specific delivery of siRNA. PMID:17670766

Liu, Bin

2007-07-31

236

Azo polymeric hydrogels for colon targeted drug delivery  

Microsoft Academic Search

Azo polymeric hydrogels were developed for colon specific targeting. Methacryloyloxy azobenzene was synthesized and hydrogels were prepared by copolymerizing with hydroxyethyl methacrylate. These hydrogels were characterized by various spectral techniques such as Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. Equilibrium swelling measurements of the hydrogels were carried out in distilled water and also in simulated gastric and

K. L. Shantha; P. Ravichandran; K. Panduranga Rao

1995-01-01

237

Toward targeted retinal drug delivery with wireless magnetic microrobots  

Microsoft Academic Search

Retinal vein occlusion is an obstruction of blood flow due to clot formation in the retinal vasculature, and is among the most common causes of vision loss. Currently, the most promising therapy involves injection of t-PA directly into small and delicate retinal vessels. This procedure requires surgical skills at the limits of human performance. In this paper, targeted retinal drug

Gorkem Dogangil; Olgaç Ergeneman; Jake J. Abbott; Salvador Pane; Heike Hall; Simon Muntwyler; Bradley J. Nelson

2008-01-01

238

An Efficient Targeted Drug Delivery through Apotransferrin Loaded Nanoparticles  

Microsoft Academic Search

BackgroundCancerous state is a highly stimulated environment of metabolically active cells. The cells under these conditions over express selective receptors for assimilation of factors essential for growth and transformation. Such receptors would serve as potential targets for the specific ligand mediated transport of pharmaceutically active molecules. The present study demonstrates the specificity and efficacy of protein nanoparticle of apotransferrin for

Athuluri Divakar Sai Krishna; Raj Kumar Mandraju; Golla Kishore; Anand Kumar Kondapi

2009-01-01

239

[Progress in the study of acid-sensitive micelles for the targeting drug delivery system].  

PubMed

As a novel targeting drug delivery system, acid-sensitive micelles have many advantages, such as increasing solubility of lipophilic drugs, acid-sensitive release, high drug loading, etc. They can load drugs though non-covalent encapsulation and covalent conjugation methods. In tumor tissues, drugs are released quickly from the depolymerized micelles with lipophilic copolymer protonation or lypohydrophilic copolymer hydrolysis and covalent conjugated drugs are released when the acid-sensitive covalent linkage breaks. This review mainly advances acid-sensitive micelles for the tumor targeting drug delivery systems from drug-loaded methods and release mechanisms. PMID:22799024

Huang, Rong-Bin; Tang, Guo-Tao

2012-04-01

240

Thermoreversible Pluronic® F127-based hydrogel containing liposomes for the controlled delivery of paclitaxel: in vitro drug release, cell cytotoxicity, and uptake studies  

PubMed Central

Purpose To develop an in situ gel system comprising liposome-containing paclitaxel (PTX) dispersed within the thermoreversible gel (Pluronic® F127 gel) for controlled release and improved antitumor drug efficiency. Methods The dialysis membrane and membrane-less diffusion method were used to investigate the in vitro drug release behavior. Differential scanning calorimetry (DSC) thermal analysis was used to investigate the “micellization” and “sol/gel transition” process of in situ gel systems. In vitro cytotoxicity and drug uptake in KB cancer cells were determined by MTT, intercellular drug concentration, and fluorescence intensity assay. Results The in vitro release experiment performed with a dialysis membrane model showed that the liposomal gel exhibited the longest drug-release period compared with liposome, general gel, and commercial formulation Taxol®. This effect is presumably due to the increased viscosity of liposomal gel, which has the effect of creating a drug reservoir. Both drug and gel release from the in situ gel system operated under zero-order kinetics and showed a correlation of release of PTX with gel, indicating a predominating release mechanism of the erosion type. Dispersing liposomes into the gel replaced larger gel itself for achieving the same gel dissolution rate. Both the critical micelle temperature and the sol/gel temperature, detected by DSC thermal analysis, were shifted to lower temperatures by adding liposomes. The extent of the shifts depended on the amount of embedded liposomes. MTT assay and drug uptake studies showed that the treatment with PTX-loaded liposomal 18% Pluronic F127 yielded cytotoxicities, intercellular fluorescence intensity, and drug concentration in KB cells much higher than that of conventional liposome, while blank liposomal 18% Pluronic F127 gel was far less than the Cremophor EL® vehicle and empty liposomes. Conclusions A thermosensitive hydrogel with embedded liposome is a promising carrier for hydrophobic anticancer agents, to be used in parenteral formulations for treating local cancers.

Nie, Shufang; Hsiao, WL Wendy; Pan, Weisan; Yang, Zhijun

2011-01-01

241

Azo polymeric hydrogels for colon targeted drug delivery.  

PubMed

Azo polymeric hydrogels were developed for colon specific targeting. Methacryloyloxy azobenzene was synthesized and hydrogels were prepared by copolymerizing with hydroxyethyl methacrylate. These hydrogels were characterized by various spectral techniques such as Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. Equilibrium swelling measurements of the hydrogels were carried out in distilled water and also in simulated gastric and intestinal fluids. The in vitro release studies of the incorporated 5-flurouracil were carried out in simulated gastric and intestinal fluids. The in vitro release profiles of the drug were also obtained in the presence of azoreductase in the culture of intestinal flora. The release was faster and almost followed a zero order pattern. This can be attributed to the cleavage of the azo crosslinks in the hydrogel by the azoreductase and the release of the entrapped drug at the site of targeting i.e., colon. PMID:8573669

Shantha, K L; Ravichandran, P; Rao, K P

1995-11-01

242

Novel colon targeted drug delivery system using natural polymers.  

PubMed

A novel colon targeted tablet formulation was developed using pectin as carrier and diltiazem HCl and indomethacin as model drugs. The tablets were coated with inulin followed by shellac and were evaluated for average weight, hardness and coat thickness. In vitro release studies for prepared tablets were carried out for 2 h in pH 1.2 HCl buffer, 3 h in pH 7.4 phosphate buffer and 6 h in simulated colonic fluid. The drug release from the coated systems was monitored using UV/Vis spectroscopy. In vitro studies revealed that the tablets coated with inulin and shellac have limited the drug release in stomach and small intestinal environment and released maximum amount of drug in the colonic environment. The study revealed that polysaccharides as carriers and inulin and shellac as a coating material can be used effectively for colon targeting of both water soluble and insoluble drugs. PMID:20390095

Ravi, V; Pramod Kumar, T M; Siddaramaiah

2008-01-01

243

Novel Colon Targeted Drug Delivery System Using Natural Polymers  

PubMed Central

A novel colon targeted tablet formulation was developed using pectin as carrier and diltiazem HCl and indomethacin as model drugs. The tablets were coated with inulin followed by shellac and were evaluated for average weight, hardness and coat thickness. In vitro release studies for prepared tablets were carried out for 2 h in pH 1.2 HCl buffer, 3 h in pH 7.4 phosphate buffer and 6 h in simulated colonic fluid. The drug release from the coated systems was monitored using UV/Vis spectroscopy. In vitro studies revealed that the tablets coated with inulin and shellac have limited the drug release in stomach and small intestinal environment and released maximum amount of drug in the colonic environment. The study revealed that polysaccharides as carriers and inulin and shellac as a coating material can be used effectively for colon targeting of both water soluble and insoluble drugs.

Ravi, V.; Pramod Kumar, T. M.; Siddaramaiah

2008-01-01

244

Targeted brain delivery of itraconazole via RVG29 anchored nanoparticles.  

PubMed

The blood-brain barrier is a major barrier in the neurological diseases treatment and precludes the entry of drugs from blood to brain. Here, we developed 29-amino-acid peptide derived from rabies virus glycoprotein (RVG29) peptide conjugated itraconazole-loaded albumin nanoparticles (RVG29-ITZ-NPs). The RVG29 peptide was conjugated to the albumin NPs using biotin-binding streptavidin as crosslinker. The NPs were characterized in terms of particle size, zeta potential, drug loading and release behavior in vitro. Cellular uptake of RVG29-ITZ-NPs was investigated by flow cytometry. Pharmacokinetics and brain distribution of RVG29-ITZ-NPs were investigated after intravenous administration of NPs. The particle size of RVG29-ITZ-NPs was 89.3?±?1.9?nm as determined by dynamic light scattering. The zeta potential of RVG29-ITZ-NPs was -33.1?±?0.9 mV. RVG29-ITZ-NPs exhibited a sustained release profile within 24?h. In vitro cellular uptake studies demonstrated that RVG29 significantly facilitated the intracellular delivery of NPs. A significant (P?

Chen, Wei; Zhan, Changyou; Gu, Bing; Meng, Qinggang; Wang, Hao; Lu, Weiyue; Hou, Huimin

2010-06-14

245

An orthopedic tissue adhesive for targeted delivery of intraoperative biologics.  

PubMed

Tissue adhesives can bind together damaged tissues and serve as tools to deliver and localize therapeutics to facilitate regeneration. One emerging therapeutic trend in orthopedics is the use of intraoperative biologics (IOB), such as bone marrow (BM) and platelet-rich plasma (PRP), to stimulate healing. Here, we introduce the application of the biomaterial chondroitin sulfate succinimidyl succinate (CS-NHS) to deliver IOB in a hydrogel adhesive. We demonstrate the biomaterial's ability to bind various tissue types and its cellular biocompatibility with encapsulated human mesenchymal stem cells (hMSCs). Further, we examine in detail the CS-NHS adhesive combined with BM aspirate for use in bone applications. hMSCs were encapsulated in CS-BM and cultured for 5 weeks in osteogenic medium. Quantitative RT-PCR demonstrated osteogenesis via upregulation of the osteogenic transcription factor Runx2 and bone markers alkaline phosphatase and osteocalcin. Significant deposition of calcium and osteocalcin was detected using biochemical, histological, and immunohistochemical techniques. Shear testing demonstrated that the CS-BM adhesive exhibited an adhesive strength approximately an order of magnitude stronger than fibrin glue and approaching that of a cyanoacrylate adhesive. These results indicate that CS-NHS is a promising delivery tool for IOB in orthopedic applications requiring a strong, degradable, and biocompatible adhesive that supports bone growth. PMID:23097279

Simson, Jacob; Crist, Joshua; Strehin, Iossif; Lu, Qiaozhi; Elisseeff, Jennifer H

2012-10-23

246

Microbial paclitaxel: advances and perspectives  

Microsoft Academic Search

Paclitaxel is a potent and widely used antitumor agent. Considerable worldwide research efforts have been carried out on different production alternatives. Since the description of the first paclitaxel-producing fungi, more than 15 years ago, microorganisms have been investigated as potential alternatives for an environmentally acceptable, relatively simple and inexpensive method to produce paclitaxel. However, in spite of significant research on

Zoila R Flores-Bustamante; Flor N Rivera-Orduña; Anahí Martínez-Cárdenas; Luis B Flores-Cotera

2010-01-01

247

A Folate Receptor-Targeting Nanoparticle Minimizes Drug Resistance in a Human Cancer Model  

PubMed Central

Resistance to chemotherapy is a major obstacle in cancer therapy. The main purpose of this study is to evaluate the potential of a folate receptor-targeting nanoparticle to overcome/minimize drug resistance and to explore the underlying mechanisms. This is accomplished with enhanced cellular accumulation and retention of paclitaxel (one of the most effective anticancer drugs in use today and a well-known P-glycoprotein (P-gp) substrate) in a P-gp-overexpressing cancer model. The folate receptor-targeted nanoparticle, HFT-T, consists of a heparin-folate-paclitaxel (HFT) backbone with an additional paclitaxel (T) loaded in its hydrophobic core. In vitro analyses demonstrated that the HFT-T nanoparticle was superior to free paclitaxel or non-targeted nanoparticle (HT-T) in inhibiting proliferation of P-gp-overexpressing cancer cells (KB-8-5), partially due to its enhanced uptake and prolonged intracellular retention. In a subcutaneous KB-8-5 xenograft model, HFT-T administration enhanced the specific delivery of paclitaxel into tumor tissues and remarkably prolonged retention within tumor tissues. Importantly, HFT-T treatment markedly retarded tumor growth in a xenograft model of resistant human squamous cancer. Immunohistochemical analysis further indicated that increased in vivo efficacy of HFT-T nanoparticles was associated with a higher degree of microtubule stabilization, mitotic arrest, antiangiogenic activity, and inhibition of cell proliferation. These findings suggest that when the paclitaxel delivered as an HFT-T nanoparticle, the drug is better retained within the P-gp-overexpressing cells than the free form of paclitaxel. These results indicated that the targeted HFT-T nanoparticle may be promising in minimizing P-gp related drug resistance and enhancing therapeutic efficacy compared with the free form of paclitaxel.

Wang, Xu; Li, Jun; Wang, Yuxiang; Koenig, Lydia; Gjyrezi, Ada; Giannakakou, Paraskevi; Shin, Edwin H.; Tighiouart, Mourad; Chen, Zhuo (Georgia); Nie, Shuming; Shin, Dong M.

2013-01-01

248

The application of carbon nanotubes in target drug delivery systems for cancer therapies  

PubMed Central

Among all cancer treatment options, chemotherapy continues to play a major role in killing free cancer cells and removing undetectable tumor micro-focuses. Although chemotherapies are successful in some cases, systemic toxicity may develop at the same time due to lack of selectivity of the drugs for cancer tissues and cells, which often leads to the failure of chemotherapies. Obviously, the therapeutic effects will be revolutionarily improved if human can deliver the anticancer drugs with high selectivity to cancer cells or cancer tissues. This selective delivery of the drugs has been called target treatment. To realize target treatment, the first step of the strategies is to build up effective target drug delivery systems. Generally speaking, such a system is often made up of the carriers and drugs, of which the carriers play the roles of target delivery. An ideal carrier for target drug delivery systems should have three pre-requisites for their functions: (1) they themselves have target effects; (2) they have sufficiently strong adsorptive effects for anticancer drugs to ensure they can transport the drugs to the effect-relevant sites; and (3) they can release the drugs from them in the effect-relevant sites, and only in this way can the treatment effects develop. The transporting capabilities of carbon nanotubes combined with appropriate surface modifications and their unique physicochemical properties show great promise to meet the three pre-requisites. Here, we review the progress in the study on the application of carbon nanotubes as target carriers in drug delivery systems for cancer therapies.

2011-01-01

249

The application of carbon nanotubes in target drug delivery systems for cancer therapies  

NASA Astrophysics Data System (ADS)

Among all cancer treatment options, chemotherapy continues to play a major role in killing free cancer cells and removing undetectable tumor micro-focuses. Although chemotherapies are successful in some cases, systemic toxicity may develop at the same time due to lack of selectivity of the drugs for cancer tissues and cells, which often leads to the failure of chemotherapies. Obviously, the therapeutic effects will be revolutionarily improved if human can deliver the anticancer drugs with high selectivity to cancer cells or cancer tissues. This selective delivery of the drugs has been called target treatment. To realize target treatment, the first step of the strategies is to build up effective target drug delivery systems. Generally speaking, such a system is often made up of the carriers and drugs, of which the carriers play the roles of target delivery. An ideal carrier for target drug delivery systems should have three pre-requisites for their functions: (1) they themselves have target effects; (2) they have sufficiently strong adsorptive effects for anticancer drugs to ensure they can transport the drugs to the effect-relevant sites; and (3) they can release the drugs from them in the effect-relevant sites, and only in this way can the treatment effects develop. The transporting capabilities of carbon nanotubes combined with appropriate surface modifications and their unique physicochemical properties show great promise to meet the three pre-requisites. Here, we review the progress in the study on the application of carbon nanotubes as target carriers in drug delivery systems for cancer therapies.

Zhang, Wuxu; Zhang, Zhenzhong; Zhang, Yingge

2011-10-01

250

Delivery of Small Interfering RNA by Peptide-Targeted Mesoporous Silica Nanoparticle-Supported Lipid Bilayers  

PubMed Central

The therapeutic potential of small interfering RNAs (siRNAs) is severely limited by the availability of delivery platforms that protect siRNA from degradation, deliver it to the target cell with high specificity and efficiency, and promote its endosomal escape and cytosolic dispersion. Here we report that mesoporous silica nanoparticle-supported lipid bilayers (or ‘protocells’), exhibit multiple properties that overcome many of the limitations of existing delivery platforms. Protocells have a 10- to 100-fold greater capacity for siRNA than corresponding lipid nanoparticles and are markedly more stable when incubated under physiological conditions. Protocells loaded with a cocktail of siRNAs bind to cells in a manner dependent on the presence of an appropriate targeting peptide and, through an endocytic pathway followed by endosomal disruption, promote delivery of the silencing nucleotides to the cytoplasm. The expression of each of the genes targeted by the siRNAs was shown to be repressed at the protein level, resulting in a potent induction of growth arrest and apoptosis. Incubation of control cells that lack expression of the antigen recognized by the targeting peptide with siRNA-loaded protocells induced neither repression of protein expression nor apoptosis, indicating the precise specificity of cytotoxic activity. In terms of loading capacity, targeting capabilities, and potency of action, protocells provide unique attributes as a delivery platform for therapeutic oligonucleotides.

Ashley, Carlee E.; Carnes, Eric C.; Epler, Katharine E.; Padilla, David P.; Phillips, Genevieve K.; Castillo, Robert E.; Wilkinson, Dan C.; Wilkinson, Brian S.; Burgard, Cameron A.; Sewell, Robin M.; Townson, Jason L.; Chackerian, Bryce; Willman, Cheryl L.; Peabody, David S.; Wharton, Walker; Brinker, C. Jeffrey

2012-01-01

251

Bacteria and pH-sensitive polysaccharide-polymer films for colon targeted delivery.  

PubMed

The colon provides drug delivery opportunities for colon-specific and systemic delivery of various therapeutic agents. Different strategies have been utilized in targeting drugs to the colon. Recently, integrated systems which incorporate dual mechanisms in colon targeted delivery have received a lot of attention. Of particular interest is bacteria-aided biomaterials and pH-sensitive polymeric film (BPSF) coating for colon targeted drug delivery. The major constituents of these films are polysaccharides and pH-sensitive polymers. The pH-sensitive polymer retards drug release in the stomach and small intestine, while the polysaccharide is digested by colonic enzymes. Digestion of the polysaccharides by bacterial glycosidic enzymes increases the pore density in the film to facilitate drug release. Generally, bacteria-aided biomaterials and pH-sensitive films can be applied to the delivery of most small organic molecules to the colon. The review encompasses the pharmaceutical design parameters such as film digestibility, swelling index and dry mass loss (that provide molecular mechanistic analysis of film permeability) as well as tensile strength, elastic modulus, and elongation at break (that describe the desirable mechanical properties of the films). A critical analysis of formulation, techniques for characterization of film properties and drug-release kinetics from these systems are emphasized. PMID:22077200

Esseku, Fredrick; Adeyeye, Moji Christianah

2011-01-01

252

Near-infrared-controlled, targeted hydrophobic drug-delivery system for synergistic cancer therapy.  

PubMed

Hydrophobicity has been an obstacle that hinders the use of many anticancer drugs. A critical challenge for cancer therapy concerns the limited availability of effective biocompatible delivery systems for most hydrophobic therapeutic anticancer drugs. In this study, we have developed a targeted near-infrared (NIR)-regulated hydrophobic drug-delivery platform based on gold nanorods incorporated within a mesoporous silica framework (AuMPs). Upon application of NIR light, the photothermal effect of the gold nanorods leads to a rapid rise in the local temperature, thus resulting in the release of the entrapped drug molecules. By integrating chemotherapy and photothermotherapy into one system, we have studied the therapeutic effects of camptothecin-loaded AuMP-polyethylene glycol-folic acid nanocarrier. Results revealed a synergistic effect in vitro and in vivo, which would make it possible to enhance the therapeutic effect of hydrophobic drugs and decrease drug side effects. Studies have shown the feasibility of using this nanocarrier as a targeted and noninvasive remote-controlled hydrophobic drug-delivery system with high spatial/temperal resolution. Owing to these advantages, we envision that this NIR-controlled, targeted drug-delivery method would promote the development of high-performance hydrophobic anticancer drug-delivery system in future clinical applications. PMID:23765904

Yang, Xinjian; Liu, Zhen; Li, Zhenhua; Pu, Fang; Ren, Jinsong; Qu, Xiaogang

2013-06-13

253

Laser-induced disruption of systemically administered liposomes for targeted drug delivery  

NASA Astrophysics Data System (ADS)

Liposomal formulations of drugs have been shown to enhance drug efficacy by prolonging circulation time, increasing local concentration and reducing off-target effects. Controlled release from these formulations would increase their utility, and hyperthermia has been explored as a stimulus for targeted delivery of encapsulated drugs. Use of lasers as a thermal source could provide improved control over the release of the drug from the liposomes with minimal collateral tissue damage. Appropriate methods for assessing local release after systemic delivery would aid in testing and development of better formulations. We use in vivo bioluminescence imaging to investigate the spatiotemporal distribution of luciferin, used as a model small molecule, and demonstrate laser-induced release from liposomes in animal models after systemic delivery. These liposomes were tested for luciferin release between 37 and 45 °C in PBS and serum using bioluminescence measurements. In vivo studies were performed on transgenic reporter mice that express luciferase constitutively throughout the body, thus providing a noninvasive readout for controlled release following systemic delivery. An Nd:YLF laser was used (527 nm) to heat tissues and induce rupture of the intravenously delivered liposomes in target tissues. These data demonstrate laser-mediated control of small molecule delivery using thermally sensitive liposomal formulations.

Mackanos, Mark A.; Larabi, Malika; Shinde, Rajesh; Simanovskii, Dmitrii M.; Guccione, Samira; Contag, Christopher H.

2009-07-01

254

Targeted drug delivery to renal proximal tubule epithelial cells mediated by 2-glucosamine.  

PubMed

In order to develop a novel kidney-targeted drug delivery system, we synthesized prednisolone carbamate-glucosamine conjugate (PCG) using 2-glucosamine as a ligand, and investigated its potential targeting efficacy. In vitro studies demonstrated that PCG could remarkably improve the uptake of drug by kidney cells. And the specific uptake of PCG could be largely reduced by the inhibitors of megalin receptor. More importantly, PCG showed an excellent kidney targeting property in vivo, and the concentration of the conjugate in the kidney was 8.1-fold higher than that of prednisolone group at 60 min after intravenous injection. Besides, PCG could significantly reverse the disease progression in renal ischemia-reperfusion (I/R) injury animal models. Furthermore, PCG presented no adverse effect on bone density while prednisolone resulted in severe osteoporosis. Thus, it indicated that 2-glucosamine could be a potential ligand for kidney-targeted delivery of prednisolone. PMID:23415893

Lin, Yan; Li, Yanping; Wang, Xiaohong; Gong, Tao; Zhang, Ling; Sun, Xun

2013-02-13

255

Anisamide-targeted cyclodextrin nanoparticles for siRNA delivery to prostate tumours in mice.  

PubMed

A hepta-guanidino-?-cyclodextrin (G-CD), its hepta-PEG conjugate (G-CD-PEG), and the corresponding anisamide-terminated PEG conjugate (G-CD-PEG-AA) have been synthesised and compared as delivery vectors for siRNA to prostate cancer cells and tumours in vivo. The G-CD-PEG-AA.siRNA formulations (in which anisamide targets the sigma receptor), but not the non-targeted formulations, induced prostate cell-specific internalisation of siRNA resulting in approximately 80% knockdown in vitro of the reporter gene, luciferase. Following intravenous administration of the anisamide-targeted formulation in a mouse prostate tumour model significant tumour inactivation with corresponding reductions in the level of vascular endothelial growth factor (VEGF) mRNA were achieved, without demonstrating enhanced toxicity. This data imply significant potential for anisamide-conjugated cyclodextrin vectors for targeted delivery of therapeutic siRNAs in the treatment of prostate cancer. PMID:22828585

Guo, Jianfeng; Ogier, Julien R; Desgranges, Stephane; Darcy, Raphael; O'Driscoll, Caitriona

2012-07-22

256

Enhancement of the efficiency of magnetic targeting for drug delivery: Development and evaluation of magnet system  

NASA Astrophysics Data System (ADS)

Deep magnetic capture and clinical application are the current trends for magnetic targeted drug delivery system. More promising and possible strategies are needed to overcome the current limitations and further improve the magnetic targeting technique. Recent advances in the development of targeting magnet system show promise in progressing this technology from the laboratory to the clinic. Starting from well-known basic concepts, current limitations of magnetic targeted drug delivery system are analyzed. Meanwhile, the design concepts and evaluations of some effective improvements in magnet system are discussed and reviewed with reference to (i) reasonable design of magnet system; (ii) control modes of magnet system used to generate dynamical magnetic fields; and (iii) magnetic field driving types.

Cao, Quanliang; Han, Xiaotao; Li, Liang

2011-08-01

257

Overcoming the stromal barrier for targeted delivery of HPMA copolymers to pancreatic tumors.  

PubMed

Delivery of macromolecules to pancreatic cancer is inhibited by a dense extracellular matrix composed of hyaluronic acid, smooth muscle actin and collagen fibers. Hyaluronic acid causes a high intratumoral fluidic pressure which prevents diffusion and penetration into the pancreatic tumor. This study involves the breaking down of hyaluronic acid by treating CAPAN-1 xenograft tumors in athymic nu/nu mice with targeted N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers radiolabeled with (111)In for single photon emission computerized tomography (SPECT) imaging. Two targeting strategies were investigated including ?v?3 integrin and HER2 receptors. HPMA copolymers were targeted to these receptors by conjugating short peptide ligands cRGDfK and KCCYSL to the side chains of the copolymer. Results demonstrate that tumor targeting can be achieved in vivo after treatment with hyaluronidase. This approach shows promise for enhanced delivery of polymer-peptide conjugates to solid tumors. PMID:23933441

Buckway, Brandon; Wang, Yongjian; Ray, Abhijit; Ghandehari, Hamidreza

2013-08-08

258

Colon-targeted quercetin delivery using natural polymer to enhance its bioavailability  

PubMed Central

The aim of the present study is to develop a polymer (Guar Gum)-based matrix tablet (using quercetin as a model drug) with sufficient mechanical strength, and promising in vitro mouth-to-colon release profile. By definition, an oral colonic delivery system should retard drug release in the stomach and small intestine, and allow complete release in the colon. By drug delivery to the colon would therefore ensure direct treatment at the disease site, lower dosing, and fewer systemic side effects. Quercetin is antioxidant in nature and used to treat colon cancer, but they have poor absorption in the upper part of the gastrointestinal tract (GIT). As a site for drug delivery, the colon offers a near neutral pH, reduced digestive enzymatic activity, a long transit time, and an increased responsiveness to absorption enhancers. By achieving a colon-targeted drug delivery system, the absorption of quercetin may be increased, which leads to better bioactivity in fewer doses.

Singhal, Anil; Jain, H.; Singhal, Vipin; Elias, Edwin J.; Showkat, Ahmad

2011-01-01

259

Actively targeting solid tumours with thermoresponsive drug delivery systems that respond to mild hyperthermia.  

PubMed

Abstract A diverse range of drug delivery vehicles have been developed to specifically target chemotherapeutics to solid tumours while avoiding systemic dose-limiting toxicity. Many of these active targeting strategies display limited efficacy because they rely on subtle differences in expression patterns between pathogenic tissue and healthy tissue. In contrast, drug delivery systems that exploit thermoresponsive behaviour allow a clinician to spatially and temporally control the accumulation and/or release of the toxic agents within tumour tissue by simply applying mild hyperthermia (defined as 39-43?°C) to the desired site. Although thermally sensitive materials comprise a significant portion of the literature on novel drug delivery systems, only a few systems have been methodically tuned to respond within this narrowly defined physiological temperature range in an in vivo environment. This review discusses the materials and strategies developed to control the primary tumour through the combined application of hyperthermia and chemotherapy. PMID:23924317

McDaniel, Jonathan R; Dewhirst, Mark W; Chilkoti, Ashutosh

2013-08-07

260

Colon-targeted delivery of live bacterial cell biotherapeutics including microencapsulated live bacterial cells  

PubMed Central

There has been an ample interest in delivery of therapeutic molecules using live cells. Oral delivery has been stipulated as best way to deliver live cells to humans for therapy. Colon, in particular, is a part of gastrointestinal (GI) tract that has been proposed to be an oral targeted site. The main objective of these oral therapy procedures is to deliver live cells not only to treat diseases like colorectal cancer, inflammatory bowel disease, and other GI tract diseases like intestinal obstruction and gastritis, but also to deliver therapeutic molecules for overall therapy in various diseases such as renal failure, coronary heart disease, hypertension, and others. This review provides a comprehensive summary of recent advancement in colon targeted live bacterial cell biotherapeutics. Current status of bacterial cell therapy, principles of artificial cells and its potentials in oral delivery of live bacterial cell biotherapeutics for clinical applications as well as biotherapeutic future perspectives are also discussed in our review.

Prakash, Satya; Malgorzata Urbanska, Aleksandra

2008-01-01

261

Molecular targeting of drug delivery systems to ovarian cancer by BH3 and LHRH peptides  

Microsoft Academic Search

Novel targeted proapoptotic anticancer drug delivery systems were developed and evaluated. Poly(ethyleneglycol) (PEG) conjugates were used as carriers. Camptothecin (CPT) was used as an anticancer agent–apoptosis inductor. Two types of molecular targets were investigated: (1) an extracellular membrane receptor specific to ovarian cancer and (2) intracellular controlling mechanisms of apoptosis. Synthetic peptides similar to luteinizing hormone-releasing hormone (LHRH) and BCL-2

S. S Dharap; B Qiu; G. C Williams; P Sinko; S Stein; T Minko

2003-01-01

262

Gene delivery targeted to the brain using an Angiopep-conjugated polyethyleneglycol-modified polyamidoamine dendrimer  

Microsoft Academic Search

Angiopep targeting to the low-density lipoprotein receptor-related protein-1 (LRP1) was identified to exhibit high transcytosis capacity and parenchymal accumulation. In this study, it was exploited as a ligand for effective brain-targeting gene delivery. Polyamidoamine dendrimers (PAMAM) were modified with angiopep through bifunctional PEG, then complexed with DNA, yielding PAMAM–PEG–Angiopep\\/DNA nanoparticles (NPs). The angiopep-modified NPs were observed to be internalized by

Weilun Ke; Kun Shao; Rongqin Huang; Liang Han; Yang Liu; Jianfeng Li; Yuyang Kuang; Liya Ye; Jinning Lou; Chen Jiang

2009-01-01

263

Exploring cell type-specific internalizing antibodies for targeted delivery of siRNA  

Microsoft Academic Search

A major challenge to the development of therapeutic small interfering RNAs (siRNAs) is specific and efficient in vivo delivery to target cells. Recent studies suggest that cell type-specific gene silencing in vivo can be achieved by combining siRNAs with cell type-specific affinity ligands such as monoclonal antibodies. The antibody-directed siRNA complex enters target cells through receptor endocytosis and is subsequently

Bin Liu

2007-01-01

264

Tumor-specific targeting of an anticancer drug delivery system by LHRH peptide  

Microsoft Academic Search

The central problem in cancer chemotherapy is the severe toxic side effects of anticancer drugs on healthy tissues. Invariably the side effects impose dose reduction, treatment delay, or discontinuance of therapy. To limit the adverse side effects of cancer chemotherapy on healthy organs, we proposed a drug delivery system (DDS) with specific targeting ligands for cancer cells. The proposed DDS

S. S. Dharap; Y. Wang; P. Chandna; J. J. Khandare; B. Qiu; S. Gunaseelan; P. J. Sinko; S. Stein; A. Farmanfarmaian; T. Minko

2005-01-01

265

A multi-scale stochastic drug release model for polymer-coated targeted drug delivery systems  

Microsoft Academic Search

A multi-scale mathematical model for drug release of oral targeted drug delivery systems was developed and applied to a commercially available delayed release tablet (Asacol®) that delivers 5-aminosalicyclic acid (5-ASA) to the colon. Underlying physical and biochemical principles governing the involved processes (diffusion and dissolution) were employed to develop the mathematical description. Finite element formulation was used to numerically solve

Nahor Haddish-Berhane; Chell Nyquist; Kamyar Haghighi; Carlos Corvalan; Ali Keshavarzian; Osvaldo Campanella; Jenna Rickus; Ashkan Farhadi

2006-01-01

266

Magnetofection: enhancing and targeting gene delivery by magnetic force in vitro and in vivo  

Microsoft Academic Search

Low efficiencies of nonviral gene vectors, the receptor-dependent host tropism of adenoviral or low titers of retroviral vectors limit their utility in gene therapy. To overcome these deficiencies, we associated gene vectors with superparamagnetic nanoparticles and targeted gene delivery by application of a magnetic field. This potentiated the efficacy of any vector up to several hundred-fold, allowed reduction of the

F. Scherer; M. Anton; U. Schillinger; J. Henkel; C. Bergemann; A. Kruger; B. Gansbacher; C. Plank

2002-01-01

267

Feasibility of targeted drug delivery to selective areas of the retina  

Microsoft Academic Search

A new method was developed to deliver locally a bolus dose of a drug to the retinal vasculature. The targeted delivery system was based on encapsulating the drug in heat-sensitive liposomes, which are injected intravenously and lysed in the retinal vessels by a heat pulse generated by a laser. To test if substances delivered in the vessels could also penetrate

Y. Ogura; T. Guran; M. Shahidi; M. T. Mori; R. C. Zeimer

1991-01-01

268

Targeted delivery of chlorotoxin-modified DNA-loaded nanoparticles to glioma via intravenous administration  

Microsoft Academic Search

Gene therapy offers great potential for brain glioma. However, therapeutic genes could not reach glioma spontaneously. A glioma-targeting gene delivery system is highly desired to transfer exogenous genes throughout the tumor focus. In this study, the nanoscopic high-branching dendrimer, polyamidoamine (PAMAM), was selected as the main vector. Chlorotoxin (CTX), which has been demonstrated to bind specifically to receptor expressed in

Rongqin Huang; Weilun Ke; Liang Han; Jianfeng Li; Shuhuan Liu; Chen Jiang

2011-01-01

269

In vitro studies on guar gum based formulation for the colon targeted delivery of Sennosides  

Microsoft Academic Search

PURPOSE: The objective of the present study is to develop colon targeted drug delivery sys- tems for sennosides using guar gum as a carrier. METHODS: Matrix tablets containing various pro- portions of guar gum were prepared by wet granula- tion technique using starch paste as a binder. The tablets were evaluated for content uniformity and in vitro drug release study

Munira Momin; K. Pundarikakshudu

270

Drug targeting to hypoxic tissue using self-inactivating bioreductive delivery systems  

Microsoft Academic Search

Hypoxia is a characteristic feature of a number of diseases including some cancers, rheumatoid arthritis and diabetes. Hypoxic tissue facilitates the use of bioreductive drug targeting systems as oxygen suppresses the release of the active drug. This review focuses on bioreductive delivery where accompanying intramolecular cyclisation negates adduct formation between the bioreductive and macromolecules such as DNA. To date, three

D. P Naughton

2001-01-01

271

Towards multifunctional, targeted drug delivery systems using mesoporous silica nanoparticles - opportunities & challenges  

NASA Astrophysics Data System (ADS)

One of the big challenges of medicine today is to deliver drugs specifically to defected cells. Nanoparticulate drug carriers have the potential to answer to this call, as nanoparticles can cross physiological barriers and access different tissues, and also be provided in a targetable form aimed at enhancing cell specificity of the carrier. Recent developments within material science and strong collaborative efforts crossing disciplinary borders have highlighted the potential of mesoporous silica nanoparticles (MSNs) for such targeted drug delivery. Here we outline recent advances which in this sense push MSNs to the forefront of drug delivery development. Relatively straightforward inside-out tuning of the vehicles, high flexibility, and potential for sophisticated release mechanisms make these nanostructures promising candidates for targeted drug delivery such as `smart' cancer therapies. Moreover, due to the large surface area and the controllable surface functionality of MSNs, they can be controllably loaded with large amounts of drugs and coupled to homing molecules to facilitate active targeting, simultaneously carrying traceable (fluorescent or magnetically active) modalities, also making them highly interesting as theragnostic agents. However, the increased relative surface area and small size, and flexible surface functionalization which is beneficially exploited in nanomedicine, consequently also includes potential risks in their interactions with biological systems. Therefore, we also discuss some safety issues regarding MSNs and highlight how different features of the drug delivery platform influence their behaviour in a biological setting. Addressing these burning questions will facilitate the application of MSNs in nanomedicine.

Rosenholm, Jessica M.; Sahlgren, Cecilia; Lindén, Mika

2010-10-01

272

Targeted nanoparticles for drug delivery through the blood–brain barrier for Alzheimer's disease  

Microsoft Academic Search

Alzheimer's disease (AD) is the most common cause of dementia among the elderly, affecting 5% of Americans over age 65, and 20% over age 80. An excess of senile plaques (?-amyloid protein) and neurofibrillary tangles (tau protein), ventricular enlargement, and cortical atrophy characterizes it. Unfortunately, targeted drug delivery to the central nervous system (CNS), for the therapeutic advancement of neurodegenerative

Celeste Roney; Padmakar Kulkarni; Veera Arora; Peter Antich; Frederick Bonte; Aimei Wu; N. N. Mallikarjuana; Sanjeev Manohar; Hsiang-Fa Liang; Anandrao R. Kulkarni; Hsing-Wen Sung; Malladi Sairam; Tejraj M. Aminabhavi

2005-01-01

273

Synthesis of Biomolecule-Modified Mesoporous Silica Nanoparticles for Targeted Hydrophobic Drug Delivery to Cancer Cells  

PubMed Central

Synthetic methodologies integrating hydrophobic drug delivery and biomolecular targeting with mesoporous silica nanoparticles are described. Transferrin and cyclic-RGD peptides are covalently attached to the nanoparticles utilizing different techniques and provide selectivity between primary and metastatic cancer cells. The increase in cellular uptake of the targeted particles is examined using fluorescence microscopy and flow cytometry. Transferrin-modified silica nanoparticles display enhancement in particle uptake by Panc-1 cancer cells over that of normal HFF cells. The endocytotic pathway for these particles is further investigated through plasmid transfection of the transferrin receptor into the normal HFF cell line, which results in an increase in particle endocytosis as compared to unmodified HFF cells. By designing and attaching a synthetic cyclic-RGD, selectivity between primary cancer cells (BT-549) and metastatic cancer cells (MDA-MB 435) is achieved with enhanced particle uptake by the metastatic cancer cell line. Incorporation of the hydrophobic drug Camptothecin into these two types of biomolecular-targeted nanoparticles causes an increase in mortality of the targeted cancer cells compared to that caused by both the free drug and nontargeted particles. These results demonstrate successful biomolecular-targeted hydrophobic drug delivery carriers that selectively target specific cancer cells and result in enhanced drug delivery and cell mortality.

Ferris, Daniel P.; Lu, Jie; Gothard, Chris; Yanes, Rolando; Thomas, Courtney R.; Olsen, John-Carl; Stoddart, J. Fraser; Tamanoi, Fuyuhiko; Zink, Jeffrey I.

2011-01-01

274

Depth-targeted transvascular drug delivery by using annular-shaped photomechanical waves  

NASA Astrophysics Data System (ADS)

Laser-based drug delivery is attractive for the targeting capability due to high spatial controllability of laser energy. Recently, we found that photomechanical waves (PMWs) can transiently increase the permeability of blood vessels in skin, muscle and brain of rats. In this study, we examined the use of annular-shaped PMWs to increase pressure at target depths due to superposition effect of pressure waves. This can increase the permeability of blood vessels located in the specific depth regions, enabling depth-targeted transvascular drug delivery. Annular PMWs were produced by irradiating a laser-absorbing material with annular-shaped pulsed laser beams that were produced by using an axicon lens. We first examined propagation and pressure characteristics of annular PMWs in tissue phantoms and confirmed an increased pressure at a target depth, which can be controlled by changing laser parameters. We injected Evans blue (EB) into a rat tail vein, and annular PMWs (inner diameter, 3 mm; outer diameter, 5 mm) were applied from the myofascial surface of the anterior tibialis muscle. After perfusion fixation, we observed fluorescence originating from EB in the tissue. We observed intense fluorescence at a target depth region of around 5 mm. These results demonstrate the capability of annular PMWs for depth-targeted transvascular drug delivery.

Akiyama, Takuya; Sato, Shunichi; Ashida, Hiroshi; Terakawa, Mitsuhiro

2011-02-01

275

Alveolar targeting of aerosol pentamidine. Toward a rational delivery system  

SciTech Connect

Nebulizer systems that deposit a high proportion of aerosolized pentamidine on large airways are likely to be associated with marked adverse side effects, which may lead to premature cessation of treatment. We have measured alveolar deposition and large airway-related side effects (e.g., cough, breathlessness, and effect on pulmonary function) after aerosolization of 150 mg pentamidine isethionate labeled with {sup 99m}Tc-Sn-colloid. Nine patients with AIDS were studied using three nebulizer systems producing different droplet size profiles: the Acorn System 22, Respirgard II, and Respirgard II with the inspiratory baffle removed. Alveolar deposition was greatest and side effects least with the nebulizer producing the smallest droplet size profile (Respirgard II), whereas large airway-related side effects were prominent and alveolar deposition lowest with the nebulizer producing the largest droplet size (Acorn System 22). Values for alveolar deposition and adverse airway effects were intermediate using the Respirgard with inspiratory baffle removed, thus indicating the importance of the baffle valve in determining droplet size. Addition of a similar baffle valve to the Acorn System 22 produced a marked improvement in droplet size profile. Selection of a nebulizer that produces an optimal droplet size range offers the advantage of enhancing alveolar targeting of aerosolized pentamidine while reducing large airway-related side effects.

Simonds, A.K.; Newman, S.P.; Johnson, M.A.; Talaee, N.; Lee, C.A.; Clarke, S.W. (Royal Free Hospital, London (England))

1990-04-01

276

A folate receptor-targeting nanoparticle minimizes drug resistance in a human cancer model.  

PubMed

Resistance to chemotherapy is a major obstacle in cancer therapy. The main purpose of this study is to evaluate the potential of a folate receptor-targeting nanoparticle to overcome/minimize drug resistance and to explore the underlying mechanisms. This is accomplished with enhanced cellular accumulation and retention of paclitaxel (one of the most effective anticancer drugs in use today and a well-known P-glycoprotein (P-gp) substrate) in a P-gp-overexpressing cancer model. The folate receptor-targeted nanoparticle, HFT-T, consists of a heparin-folate-paclitaxel (HFT) backbone with an additional paclitaxel (T) loaded in its hydrophobic core. In vitro analyses demonstrated that the HFT-T nanoparticle was superior to free paclitaxel or nontargeted nanoparticle (HT-T) in inhibiting proliferation of P-gp-overexpressing cancer cells (KB-8-5), partially due to its enhanced uptake and prolonged intracellular retention. In a subcutaneous KB-8-5 xenograft model, HFT-T administration enhanced the specific delivery of paclitaxel into tumor tissues and remarkably prolonged retention within tumor tissues. Importantly, HFT-T treatment markedly retarded tumor growth in a xenograft model of resistant human squamous cancer. Immunohistochemical analysis further indicated that increased in vivo efficacy of HFT-T nanoparticles was associated with a higher degree of microtubule stabilization, mitotic arrest, antiangiogenic activity, and inhibition of cell proliferation. These findings suggest that when the paclitaxel was delivered as an HFT-T nanoparticle, the drug is better retained within the P-gp-overexpressing cells than the free form of paclitaxel. These results indicated that the targeted HFT-T nanoparticle may be promising in minimizing P-gp related drug resistance and enhancing therapeutic efficacy compared with the free form of paclitaxel. PMID:21728341

Wang, Xu; Li, Jun; Wang, Yuxiang; Koenig, Lydia; Gjyrezi, Ada; Giannakakou, Paraskevi; Shin, Edwin H; Tighiouart, Mourad; Chen, Zhuo Georgia; Nie, Shuming; Shin, Dong M

2011-07-11

277

Nanoparticles of 2-deoxy-d-glucose functionalized poly(ethylene glycol)-co-poly(trimethylene carbonate) for dual-targeted drug delivery in glioma treatment.  

PubMed

Based on the facilitative glucose transporter (GLUT) over-expression on both blood-brain barrier (BBB) and glioma cells, 2-deoxy-d-glucose modified poly(ethylene glycol)-co-poly(trimethylene carbonate) nanoparticles (dGlu-NP) were developed as a potential dual-targeted drug delivery system for enhancing the BBB penetration via GLUT-mediated transcytosis and improving the drug accumulation in the glioma via GLUT-mediated endocytosis. In vitro physicochemical characterization of the dual-targeted nanoparticulate system presented satisfactory size of 71 nm with uniform distribution, high encapsulation efficiency and adequate loading capacity of paclitaxel (PTX). Compared with non-glucosylated nanoparticles (NP), a significantly higher amount of dGlu-NP was internalized by RG-2 glioma cells through caveolae-mediated and clathrin-mediated endocytosis. Both of the transport ratios across the in vitro BBB model and the cytotoxicity of RG-2 cells after crossing the BBB were significantly greater of dGlu-NP/PTX than that of NP/PTX. In vivo fluorescent image indicated that dGlu-NP had high specificity and efficiency in intracranial tumor accumulation. The anti-glioblastoma efficacy of dGlu-NP/PTX was significantly enhanced in comparison with that of Taxol and NP/PTX. Preliminary safety tests showed no acute toxicity to hematological system, liver, kidney, heart, lung and spleen in mice after intravenous administration at a dose of 100 mg/kg blank dGlu-NP per day for a week. Therefore, these results indicated that dGlu-NP developed in this study could be a potential dual-targeted vehicle for brain glioma therapy. PMID:24125772

Jiang, Xinyi; Xin, Hongliang; Ren, Qiuyue; Gu, Jijin; Zhu, Lingjun; Du, Fengyi; Feng, Chunlai; Xie, Yike; Sha, Xianyi; Fang, Xiaoling

2013-10-11

278

Iron Oxide Nanoparticles as a Drug Delivery Vehicle for MRI Monitored Magnetic Targeting of Brain Tumors  

PubMed Central

This study explored the possibility of utilizing iron oxide nanoparticles as a drug delivery vehicle for minimally invasive, MRI-monitored magnetic targeting of brain tumors. In vitro determined hydrodynamic diameter of ~100nm, saturation magnetization of 94 emu/g Fe and T2 relaxivity of 43 s?1mM?1 of the nanoparticles suggested their applicability for this purpose. In vivo effect of magnetic targeting on the extent and selectivity of nanoparticle accumulation in tumors of rats harboring orthotopic 9L-gliosarcomas was quantified with MRI. Animals were intravenously injected with nanoparticles (12 mg Fe/kg) under a magnetic field density of 0 T (control) or 0.4 T (experimental) applied for 30 minutes. MR images were acquired prior to administration of nanoparticles and immediately after magnetic targeting at 1 hour intervals for 4 hours. Image analysis revealed that magnetic targeting induced a 5-fold increase in the total glioma exposure to magnetic nanoparticles over non-targeted tumors (p=0.005) and a 3.6-fold enhancement in the target selectivity index of nanoparticle accumulation in glioma over the normal brain (p=0.025). In conclusion, accumulation of iron oxide nanoparticles in gliosarcomas can be significantly enhanced by magnetic targeting and successfully quantified by MR imaging. Hence, these nanoparticles appear to be a promising vehicle for glioma-targeted drug delivery.

Chertok, Beata; Moffat, Bradford A.; David, Allan E.; Yu, Faquan; Bergemann, Christian; Ross, Brian D.; Yang, Victor C.

2009-01-01

279

Cutting-edge technologies in colon-targeted drug delivery systems.  

PubMed

Oral colon-targeted drug delivery systems have gained enormous attention among researchers in the last two decades. The significance of this site-specific drug delivery system can be measured by its usefulness for delivering a variety of therapeutic agents, both for the treatment of local diseases or for systemic therapies. With the arrival of newer innovations, a large number of breakthrough technologies have emerged for targeting a drug molecule to the colon. Researchers have attempted various approaches in the development of these formulation technologies, such as pH-dependent, time-dependent and microflora-activated systems. Recently, a number of approaches have been proposed that utilize a novel concept of di-dependent drug delivery systems, that is, the systems in which the drug release is controlled by two factors: pH and time, and pH and microflora of the colon. This Editorial article is not intended to offer a comprehensive review on drug delivery, but shall familiarize the readers with the formulation technologies that have been developed for attaining colon-specific drug delivery. PMID:21933030

Patel, Mayur M

2011-10-01

280

Bioresponsive hyaluronic acid-capped mesoporous silica nanoparticles for targeted drug delivery.  

PubMed

In this paper, we present a facile strategy to synthesize hyaluronic acid (HA) conjugated mesoporous silica nanoparticles (MSP) for targeted enzyme responsive drug delivery, in which the anchored HA polysaccharides not only act as capping agents but also as targeting ligands without the need of additional modification. The nanoconjugates possess many attractive features including chemical simplicity, high colloidal stability, good biocompatibility, cell-targeting ability, and precise cargo release, making them promising agents for biomedical applications. As a proof-of-concept demonstration, the nanoconjugates are shown to release cargoes from the interior pores of MSPs upon HA degradation in response to hyaluronidase-1 (Hyal-1). Moreover, after receptor-mediated endocytosis into cancer cells, the anchored HA was degraded into small fragments, facilitating the release of drugs to kill the cancer cells. Overall, we envision that this system might open the door to a new generation of carrier system for site-selective, controlled-release delivery of anticancer drugs. PMID:23303570

Chen, Zhaowei; Li, Zhenhua; Lin, Youhui; Yin, Meili; Ren, Jinsong; Qu, Xiaogang

2013-01-09

281

Targeted delivery of nano-therapeutics for major disorders of the central nervous system.  

PubMed

Major central nervous system (CNS) disorders, including brain tumors, Alzheimer’s disease, Parkinson’s disease, and stroke, are significant threats to human health. Although impressive advances in the treatment of CNS disorders have been made during the past few decades, the success rates are still moderate if not poor. The blood–brain barrier (BBB) hampers the access of systemically administered drugs to the brain. The development of nanotechnology provides powerful tools to deliver therapeutics to target sites. Anchoring them with specific ligands can endow the nano-therapeutics with the appropriate properties to circumvent the BBB. In this review, the potential nanotechnology-based targeted drug delivery strategies for different CNS disorders are described. The limitations and future directions of brain-targeted delivery systems are also discussed. PMID:23797465

Gao, Huile; Pang, Zhiqing; Jiang, Xinguo

2013-10-01

282

Influence of Red Blood Cells on Nanoparticle Targeted Delivery in Microcirculation  

PubMed Central

Multifunctional nanomedicine holds considerable promise as the next generation of medicine that allows for targeted therapy with minimal toxicity. Most current studies on Nanoparticle (NP) drug delivery consider a Newtonian fluid with suspending NPs. However, blood is a complex biological fluid composed of deformable cells, proteins, platelets, and plasma. For blood flow in capillaries, arterioles and venules, the particulate nature of the blood needs to be considered in the delivery process. The existence of the cell-free-layer and NP-cell interaction will largely influence both the dispersion and binding rates, thus impact targeted delivery efficacy. In this paper, a particle-cell hybrid model is developed to model NP transport, dispersion, and binding dynamics in blood suspension. The motion and deformation of red blood cells is captured through the Immersed Finite Element Method. The motion and adhesion of individual NPs are tracked through Brownian adhesion dynamics. A mapping algorithm and an interaction potential function are introduced to consider the cell-particle collision. NP dispersion and binding rates are derived from the developed model under various rheology conditions. The influence of red blood cells, vascular flow rate, and particle size on NP distribution and delivery efficacy is characterized. A non-uniform NP distribution profile with higher particle concentration near the vessel wall is observed. Such distribution leads to over 50% higher particle binding rate compared to the case without RBC considered. The tumbling motion of RBCs in the core region of the capillary is found to enhance NP dispersion, with dispersion rate increases as shear rate increases. Results from this study contribute to the fundamental understanding and knowledge on how the particulate nature of blood influences NP delivery, which will provide mechanistic insights on the nanomedicine design for targeted drug delivery applications.

Tan, Jifu; Thomas, Antony; Liu, Yaling

2012-01-01

283

Influence of Red Blood Cells on Nanoparticle Targeted Delivery in Microcirculation.  

PubMed

Multifunctional nanomedicine holds considerable promise as the next generation of medicine that allows for targeted therapy with minimal toxicity. Most current studies on Nanoparticle (NP) drug delivery consider a Newtonian fluid with suspending NPs. However, blood is a complex biological fluid composed of deformable cells, proteins, platelets, and plasma. For blood flow in capillaries, arterioles and venules, the particulate nature of the blood needs to be considered in the delivery process. The existence of the cell-free-layer and NP-cell interaction will largely influence both the dispersion and binding rates, thus impact targeted delivery efficacy. In this paper, a particle-cell hybrid model is developed to model NP transport, dispersion, and binding dynamics in blood suspension. The motion and deformation of red blood cells is captured through the Immersed Finite Element Method. The motion and adhesion of individual NPs are tracked through Brownian adhesion dynamics. A mapping algorithm and an interaction potential function are introduced to consider the cell-particle collision. NP dispersion and binding rates are derived from the developed model under various rheology conditions. The influence of red blood cells, vascular flow rate, and particle size on NP distribution and delivery efficacy is characterized. A non-uniform NP distribution profile with higher particle concentration near the vessel wall is observed. Such distribution leads to over 50% higher particle binding rate compared to the case without RBC considered. The tumbling motion of RBCs in the core region of the capillary is found to enhance NP dispersion, with dispersion rate increases as shear rate increases. Results from this study contribute to the fundamental understanding and knowledge on how the particulate nature of blood influences NP delivery, which will provide mechanistic insights on the nanomedicine design for targeted drug delivery applications. PMID:22375153

Tan, Jifu; Thomas, Antony; Liu, Yaling

2011-12-22

284

Targeted Delivery of Nanoparticles to Ischemic Muscle for Imaging and Therapeutic Angiogenesis  

PubMed Central

Targeting of nanoparticles to ischemic tissues was studied in a murine ischemic hindlimb model. Intravenously injected fluorescent nanoparticles allowed ischemia-targeted imaging of ischemic muscles due to increased permeability of blood vessels in hypoxic tissues. Targeting efficiency correlated with blood perfusion after induction of ischemia and was enhanced in early stage of ischemia (<7 days). Therapeutic delivery of vascular endothelial growth factor (VEGF) was achieved by VEGF-conjugated nanoparticles and resulted in a 1.7-fold increase in blood perfusion, as compared to control mice. This work supports the application of nanoparticles as imaging and therapeutic modalities for ischemia treatment.

Kim, Jaeyun; Cao, Lan; Shvartsman, Dmitry; Silva, Eduardo A.; Mooney, David J.

2010-01-01

285

Targeted Delivery of Cisplatin to Lung Cancer Using ScFvEGFR-Heparin-Cisplatin Nanoparticles  

PubMed Central

The clinical application of cis-diamminedichloroplatinum(II) (DDP, cisplatin) for cancer therapy is limited by its non-specific biodistribution and severe side effects. Here, we have developed EGFR-targeted heparin-DDP (EHDDP) nanoparticles for tumor targeted delivery of DDP. This nanoparticle delivery system possesses the following unique properties: i) the succinic anhydride-modified heparin is biocompatible and biodegradable with no anticoagulant activity; ii) the single chain variable fragment anti-EGFR antibody (ScFvEGFR) was conjugated to the nanoparticles as an EGFR-targeting ligand. Our results showed that EHDDP nanoparticles can significantly increase the intracellular concentrations of DDP and Pt-DNA adducts in EGFR-expressing non-small cell lung cancer H292 cells via an EGFR-mediated pathway. Compared to the free DDP, significantly prolonged blood circulation time and improved pharmacokinetics and biodistribution of Pt were observed after systemic delivery of the EHDDP nanoparticles. The new EHDDP nanoparticle delivery system significantly enhanced antitumor activity of DDP without weight loss or damage to the kidney and spleen in nude mice bearing H292 cell tumors.

Peng, Xiang-Hong; Wang, Yiqing; Huang, Donghai; Wang, Yuxiang; Shin, Hyung Juc.; Chen, Zhengjia; Spewak, Micheal B; Mao, Hui; Wang, Xu; Wang, Ying; Chen, Zhuo (Georgia); Nie, Shuming; Shin, Dong M.

2011-01-01

286

MSCs: Delivery Routes and Engraftment, Cell-Targeting Strategies, and Immune Modulation.  

PubMed

Mesenchymal stem cells (MSCs) are currently being widely investigated both in the lab and in clinical trials for multiple disease states. The differentiation, trophic, and immunomodulatory characteristics of MSCs contribute to their therapeutic effects. Another often overlooked factor related to efficacy is the degree of engraftment. When reported, engraftment is generally low and transient in nature. MSC delivery methods should be tailored to the lesion being treated, which may be local or systemic, and customized to the mechanism of action of the MSCs, which can also be local or systemic. Engraftment efficiency is enhanced by using intra-arterial delivery instead of intravenous delivery, thus avoiding the "first-pass" accumulation of MSCs in the lung. Several methodologies to target MSCs to specific organs are being developed. These cell targeting methodologies focus on the modification of cell surface molecules through chemical, genetic, and coating techniques to promote selective adherence to particular organs or tissues. Future improvements in targeting and delivery methodologies to improve engraftment are expected to improve therapeutic results, extend the duration of efficacy, and reduce the effective (MSC) therapeutic dose. PMID:24000286

Kean, Thomas J; Lin, Paul; Caplan, Arnold I; Dennis, James E

2013-08-13

287

Peptide- and saccharide-conjugated dendrimers for targeted drug delivery: a concise review  

PubMed Central

Dendrimers comprise a category of branched materials with diverse functions that can be constructed with defined architectural and chemical structures. When decorated with bioactive ligands made of peptides and saccharides through peripheral chemical groups, dendrimer conjugates are turned into nanomaterials possessing attractive binding properties with the cognate receptors. At the cellular level, bioactive dendrimer conjugates can interact with cells with avidity and selectivity, and this function has particularly stimulated interests in investigating the targeting potential of dendrimer materials for the design of drug delivery systems. In addition, bioactive dendrimer conjugates have so far been studied for their versatile capabilities to enhance stability, solubility and absorption of various types of therapeutics. This review presents a brief discussion on three aspects of the recent studies to use peptide- and saccharide-conjugated dendrimers for drug delivery: (i) synthesis methods, (ii) cell- and tissue-targeting properties and (iii) applications of conjugated dendrimers in drug delivery nanodevices. With more studies to elucidate the structure–function relationship of ligand–dendrimer conjugates in transporting drugs, the conjugated dendrimers hold promise to facilitate targeted delivery and improve drug efficacy for discovery and development of modern pharmaceutics.

Liu, Jie; Gray, Warren D.; Davis, Michael E.; Luo, Ying

2012-01-01

288

Image-guided, targeted and triggered drug delivery to tumors using polymer-based microbubbles.  

PubMed

Microbubbles (MB) are routinely used contrast agents for functional and molecular ultrasound (US) imaging. In addition, they have been attracting more and more attention for drug delivery purposes, enabling e.g. US-mediated drug delivery across biological barriers and US-induced triggered drug release from the MB shell. The vast majority of efforts in this regard have thus far focused on phospholipid-based soft-shell MB, which are suboptimal for stably incorporating large amounts of drug molecules because of their relatively thin shell. Using poly(butyl cyanoacrylate) (PBCA)-based hard-shell MB, we show here that both hydrophilic (Rhodamine-B) and hydrophobic (Coumarin-6) model drugs can be efficiently and stably entrapped within the ~50 nm shell of PBCA MB. In addition, we demonstrate that model drug loading does not negatively affect the acoustic properties of the MB, and that functionalizing the surface of fluorophore-loaded MB with anti-VEGFR2 antibodies enables image-guided and targeted model drug delivery to tumor blood vessels. Finally, we show both in vitro and in vivo that disintegrating VEGFR2-targeted MB with high-mechanical index US pulses leads to high levels of model drug release. Consequently, these findings indicate that polymer-based MB are highly suitable systems for image-guided, targeted and triggered drug delivery to tumors and tumor blood vessels. PMID:22580225

Fokong, Stanley; Theek, Benjamin; Wu, Zhuojun; Koczera, Patrick; Appold, Lia; Jorge, Samuel; Resch-Genger, Ute; van Zandvoort, Marc; Storm, Gert; Kiessling, Fabian; Lammers, Twan

2012-05-09

289

Targeted drug-delivery approaches by nanoparticulate carriers in the therapy of inflammatory diseases  

PubMed Central

Limitations in therapy induced by adverse effects due to unselective drug availability and therefore the use of potentially too high doses are a common problem. One prominent example for this dilemma are inflammatory diseases. Colloidal carriers allow one to improve delivery of drugs to the site of action and appear promising to overcome this general therapeutic drawback. Specific uptake of nanoparticles by immune-related cells in inflamed barriers offers selective drug targeting to the inflamed tissue. Here we focus on nanocarrier-based drug delivery strategies for the treatment of common inflammatory disorders like rheumatoid arthritis, multiple sclerosis, uveitis or inflammatory bowel disease.

Ulbrich, Wiebke; Lamprecht, Alf

2010-01-01

290

Surface proteomic analysis of osteosarcoma identifies EPHA2 as receptor for targeted drug delivery.  

PubMed

Background:Osteosarcoma (OS) is the most common bone tumour in children and adolescents. Despite aggressive therapy regimens, treatment outcomes are unsatisfactory. Targeted delivery of drugs can provide higher effective doses at the site of the tumour, ultimately improving the efficacy of existing therapy. Identification of suitable receptors for drug targeting is an essential step in the design of targeted therapy for OS.Methods:We conducted a comparative analysis of the surface proteome of human OS cells and osteoblasts using cell surface biotinylation combined with nano-liquid chromatography - tandem mass spectrometry-based proteomics to identify surface proteins specifically upregulated on OS cells. This approach generated an extensive data set from which we selected a candidate to study for its suitability as receptor for targeted treatment delivery to OS. First, surface expression of the ephrin type-A receptor 2 (EPHA2) receptor was confirmed using FACS analysis. Ephrin type-A receptor 2 expression in human tumour tissue was tested using immunohistochemistry. Receptor targeting and internalisation studies were conducted to assess intracellular uptake of targeted modalities via EPHA2. Finally, tissue micro arrays containing cores of human OS tissue were stained using immunohistochemistry and EPHA2 staining was correlated to clinical outcome measures.Results:Using mass spectrometry, a total of 2841 proteins were identified of which 156 were surface proteins significantly upregulated on OS cells compared with human primary osteoblasts. Ephrin type-A receptor 2 was highly upregulated and the most abundant surface protein on OS cells. In addition, EPHA2 was expressed in a vast majority of human OS samples. Ephrin type-A receptor 2 effectively mediates internalisation of targeted adenoviral vectors into OS cells. Patients with EPHA2-positive tumours showed a trend toward inferior overall survival.Conclusion:The results presented here suggest that the EPHA2 receptor can be considered an attractive candidate receptor for targeted delivery of therapeutics to OS. PMID:24064975

Posthumadeboer, J; Piersma, S R; Pham, T V; van Egmond, P W; Knol, J C; Cleton-Jansen, A M; van Geer, M A; van Beusechem, V W; Kaspers, G J L; van Royen, B J; Jiménez, C R; Helder, M N

2013-09-24

291

Nanoparticles-mediated drug delivery approaches for cancer targeting: a review.  

PubMed

Cancer has become the leading cause of death among different populations of the world. The treatment is limited to chemotherapy, radiation, and surgery. Selective targeting to the tumor cells is possible by nanoparticles-based drug delivery system. It maximizes the drug concentration at the desired target and protects the surrounding healthy tissues at the same time. To improve the targeting potential of the anticancer drugs, nanoparticles were optimized for the size and surface characteristics to enhance their circulation time and targeting efficiency. Passive targeting involves surface modification with polyethylene glycol to avoid its elimination by natural body defense mechanism. Active targeting involves chemical interaction with certain antigen, receptors, and genes which are over expressed during progression of disease. In addition, the article highlights recent developments in "smart"-stimulus-responsive-drug carriers designed to enhance the localization and efficacy of therapeutic payloads as compared with free drug. Enhanced targeting potential, imaging, and controlled release of drugs or therapeutic molecules could be possible through multi-functional nanocarrier. Such multi-faceted, versatile nanocarriers and drug delivery systems promise a substantial increase in the efficacy of diagnostic and therapeutic applications in pharmaceutical sciences. PMID:22873288

Sultana, Shaheen; Khan, Mohd Rashid; Kumar, Mukesh; Kumar, Sokindra; Ali, Mohammed

2012-08-09

292

Molecular design and nanoparticle-mediated intracellular delivery of functional proteins to target cellular pathways  

NASA Astrophysics Data System (ADS)

Intracellular delivery of specific proteins and peptides represents a novel method to influence stem cells for gain-of-function and loss-of-function. Signaling control is vital in stem cells, wherein intricate control of and interplay among critical pathways directs the fate of these cells into either self-renewal or differentiation. The most common route to manipulate cellular function involves the introduction of genetic material such as full-length genes and shRNA into the cell to generate (or prevent formation of) the target protein, and thereby ultimately alter cell function. However, viral-mediated gene delivery may result in relatively slow expression of proteins and prevalence of oncogene insertion into the cell, which can alter cell function in an unpredictable fashion, and non-viral delivery may lead to low efficiency of genetic delivery. For example, the latter case plagues the generation of induced pluripotent stem cells (iPSCs) and hinders their use for in vivo applications. Alternatively, introducing proteins into cells that specifically recognize and influence target proteins, can result in immediate deactivation or activation of key signaling pathways within the cell. In this work, we demonstrate the cellular delivery of functional proteins attached to hydrophobically modified silica (SiNP) nanoparticles to manipulate specifically targeted cell signaling proteins. In the Wnt signaling pathway, we have targeted the phosphorylation activity of glycogen synthase kinase-3beta (GSK-3beta) by designing a chimeric protein and delivering it in neural stem cells. Confocal imaging indicates that the SiNP-chimeric protein conjugates were efficiently delivered to the cytosol of human embryonic kidney cells and rat neural stem cells, presumably via endocytosis. This uptake impacted the Wnt signaling cascade, indicated by the elevation of beta-catenin levels, and increased transcription of Wnt target genes, such as c-MYC. The results presented here suggest that functional proteins can be delivered intracellularly in vitro using nanoparticles and used to target key signaling proteins and regulate cell signaling pathways. The same concept of naturally occurring protein-protein interactions can also be implemented to selectively bring intracellular protein targets in close proximity to proteasomal degradation machinery in cells and effect their depletion from the cellular compartments. This approach will be able to not only target entire pool of proteins to ubiquitination-mediated degradation, but also to specific sub-pools of posttranslationally modified proteins in the cell, provided peptides having distinct binding affinities are identified for posttranslational modifications. This system can then be tested for intracellular protein delivery using nanoparticle carriers to identify roles of different posttranslational modifications on the protein's activity. In future work, we propose to develop a cellular detection system, based on GFP complementation, which can be used to evaluate the efficiency of different protein delivery carriers to internalize proteins into the cell cytosol. We envision the application of nanoscale materials as intracellular protein delivery vehicles to target diverse cell signaling pathways at the posttranslational level, and subsequent metabolic manipulation, which may have interesting therapeutic properties and can potentially target stem cell fate.

Shah, Dhiral Ashwin

293

A ligand-mediated nanovector for targeted gene delivery and transfection in cancer cells  

PubMed Central

As conventional cancer therapies struggle with toxicity issues and irregular remedial efficacy, the preparation of novel gene therapy vectors could offer clinicians the tools for addressing the genetic errors of diseased tissue. The transfer of gene therapy to the clinic has proven difficult due to safety, target specificity, and transfection efficiency concerns. Polyethylenimine (PEI) nanoparticles have been identified as promising gene carriers that induce gene transfection with high efficiency. However, the inherent toxicity of the material and non-selective delivery are the major concerns in applying these particles clinically. Here, a non-viral nanovector has been developed by PEGylation of DNA-complexing PEI in nanoparticles functionalized with an Alexa Fluor 647 near infrared fluorophore, and the chlorotoxin (CTX) peptide which binds specifically to many forms of cancer. With this nanovector, the potential toxicity to healthy cells is minimized by both the reduction of the toxicity of PEI with the biocompatible copolymer and the targeted delivery of the nanovector to cancer cells, as evaluated by viability studies. The nanovector demonstrated high levels of targeting specificity and gene transfection efficiency with both C6 glioma and DAOY medulloblastoma tumor cells. Significantly, with the CTX as the targeting ligand, the nanovector may serve as a widely applicable gene delivery system for a broad array of cancer types.

Veiseh, Omid; Kievit, Forrest; Gunn, Jonathan; Ratner, Buddy; Zhang, Miqin

2009-01-01

294

LIPOSOMAL MODULAR COMPLEXES FOR SIMULTANEOUS TARGETED DELIVERY OF BIOACTIVE GASES AND THERAPEUTICS  

PubMed Central

Intrinsically echogenic liposomes (ELIP) can be adapted to encapsulate nitric oxide to facilitate ultrasound-enhanced delivery of therapeutic agents to atherosclerotic plaques. However, the NO loading of targeted ELIP caused a 93% decrease of antibody (Ab) immunoreactivity. The following hypothesis was tested: biotin/avidin-mediated coupling of NO-ELIP and Ab-conjugated ELIP will enable co-delivery of bioactive gases and ELIP that can encapsulate other agents without loss of targeting efficiency. Complex formation was initiated by addition of excess streptavidin to equal proportions of biotinylated Ab-ELIP and NO-ELIP. Fluorescence deconvolution microscopy, Coulter Multisizer 3 analysis and flow cytometry demonstrated that the ELIP coupling procedure formed mixed aggregates of ?10 liposomes within 1 minute. Intravascular ultrasound imaging and ELISA showed that echogenicity and targeting efficiency were completely and 69–99% retained, respectively. When complexed to NO-ELIP, ELIP bifunctionally targeted to both CD34 and ICAM-1 (BF-ELIP) increased human mononuclear cell migration through human coronary artery endothelial cell monolayers in transwell plates 4-fold relative to a nonspecific IgG-ELIP control and 2-fold relative to BF-ELIP alone. It was concluded that this novel multi-functional conjugation methodology provides a platform technology for site-specific co-delivery of bioactive gases and other agents.

Klegerman, Melvin E.; Wassler, Michael; Huang, Shao-Ling; Zou, Yuejiao; Kim, Hyunggun; Shelat, Harnath S.; Holland, Christy K.; Geng, Yong-Jian; McPherson, David D.

2010-01-01

295

Targeted Delivery of VEGF after a Myocardial Infarction Reduces Collagen Deposition and Improves Cardiac Function  

PubMed Central

The development of adjunctive therapies which attenuate adverse remodeling and improve LV function post myocardial infarction (MI) is of significant clinical interest. Previously, we have shown that targeted delivery of therapeutic vascular endothelial growth factor (VEGF) to the infarct border zone significantly increases vascular perfusion and results in improvements in LV function. In this study, we tested the hypothesis that improvements in cardiac function observed with this novel targeted drug delivery system strongly correlate with reductions in collagen deposition in the scar tissue after an MI. Rats received anti-P-selectin conjugated immunoliposomes containing VEGF immediately post-MI. Over 4 weeks, evolutionary changes in LV geometry and function were correlated with collagen deposition and infarct size quantified by Gomori's trichrome and picrosirius red staining. Targeted VEGF treated hearts showed a 37% decrease in collagen deposition in the anterior wall, as well as significant improvements in LV filling pressures. Multi-regression analysis showed that the extent of collagen deposition post MI can be predicted by a linear combination of normalized LV mass and ejection fraction. Targeted delivery of VEGF post-MI results in significant decreases in collagen deposition and adverse remodeling. Improvements in cardiac function in this model are related to degree of collagen deposition and extent of scar formation.

Rosano, Jenna M.; Cheheltani, Rabee; Wang, Bin; Vora, Hardik; Kiani, Mohammad F.; Crabbe, Deborah L.

2012-01-01

296

Targeted drug delivery for cancer therapy: the other side of antibodies  

PubMed Central

Therapeutic monoclonal antibody (TMA) based therapies for cancer have advanced significantly over the past two decades both in their molecular sophistication and clinical efficacy. Initial development efforts focused mainly on humanizing the antibody protein to overcome problems of immunogenicity and on expanding of the target antigen repertoire. In parallel to naked TMAs, antibody-drug conjugates (ADCs) have been developed for targeted delivery of potent anti-cancer drugs with the aim of bypassing the morbidity common to conventional chemotherapy. This paper first presents a review of TMAs and ADCs approved for clinical use by the FDA and those in development, focusing on hematological malignancies. Despite advances in these areas, both TMAs and ADCs still carry limitations and we highlight the more important ones including cancer cell specificity, conjugation chemistry, tumor penetration, product heterogeneity and manufacturing issues. In view of the recognized importance of targeted drug delivery strategies for cancer therapy, we discuss the advantages of alternative drug carriers and where these should be applied, focusing on peptide-drug conjugates (PDCs), particularly those discovered through combinatorial peptide libraries. By defining the advantages and disadvantages of naked TMAs, ADCs and PDCs it should be possible to develop a more rational approach to the application of targeted drug delivery strategies in different situations and ultimately, to a broader basket of more effective therapies for cancer patients.

2012-01-01

297

Intrapericardial Delivery of Gelfoam Enables the Targeted Delivery of Periostin Peptide after Myocardial Infarction by Inducing Fibrin Clot Formation  

PubMed Central

Background Administration of a recombinant peptide of Periostin (rPN) has recently been shown to stimulate cardiomyocyte proliferation and angiogensis after myocardial infarction (MI) [1]. However, strategies for targeting the delivery of rPN to the heart are lacking. Intrapericardial administration of drug-eluting hydrogels may provide a clinically viable strategy for increasing myocardial retention, therapeutic efficacy, and bioactivity of rPN and to decrease systemic re-circulation. Methods and Results We investigated the ability of intrapericardial injections of drug-eluting hydrogels to deliver and prolong the release of rPN to the myocardium in a large animal model of myocardial infarction. Gelfoam is an FDA-approved hemostatic material commonly used in surgery, and is known to stimulate fibrin clot formation. We show that Gelfoam disks loaded with rPN, when implanted within the pericardium or peritoneum of mammals becomes encapsulated within a non-fibrotic fibrin-rich hydrogel, prolonging the in vitro and in vivo release of rPN. Administration into the pericardial cavity of pigs, following a complete occlusion of the left anterior descending artery, leads to greater induction of cardiomyocyte mitosis, increased cardiomyocyte cell cycle activity, and enhanced angiogenesis compared to direct injection of rPN alone. Conclusions The results of this study suggest that intrapericardial drug delivery of Gelfoam, enhanced by triggered clot formation, can be used to effectively deliver rPN to the myocardium in a clinically relevant model of myocardial infarction. The work presented here should enhance the translational potential of pharmaceutical-based strategies that must be targeted to the myocardium.

Polizzotti, Brian D.; Arab, Shima; Kuhn, Bernhard

2012-01-01

298

LHRH-Targeted Nanogels as a Delivery System for Cisplatin to Ovarian Cancer.  

PubMed

Targeted drug delivery using multifunctional polymeric nanocarriers is a modern approach for cancer therapy. Our purpose was to prepare targeted nanogels for selective delivery of chemotherapeutic agent cisplatin to luteinizing hormone-releasing hormone (LHRH) receptor overexpressing tumor in vivo. Building blocks of such delivery systems consisted of innovative soft block copolymer nanogels with ionic cores serving as a reservoir for cisplatin (loading 35%) and a synthetic analogue of LHRH conjugated to the nanogels via poly(ethylene glycol) spacer. Covalent attachment of (d-Lys6)-LHRH to nanogels was shown to be possible without loss in either the ligand binding affinity or the nanogel drug incorporation ability. LHRH-nanogel accumulation was specific to the LHRH-receptor positive A2780 ovarian cancer cells and not toward LHRH-receptor negative SKOV-3 cells. The LHRH-nanogel cisplatin formulation was more effective and less toxic than equimolar doses of free cisplatin or untargeted nanogels in the treatment of receptor-positive ovarian cancer xenografts in mice. Collectively, the study indicates that LHRH mediated nanogel-cisplatin delivery is a promising formulation strategy for therapy of tumors that express the LHRH receptor. PMID:23957812

Nukolova, Natalia V; Oberoi, Hardeep S; Zhao, Yi; Chekhonin, Vladimir P; Kabanov, Alexander V; Bronich, Tatiana K

2013-08-30

299

A fullerene-paclitaxel chemotherapeutic: synthesis, characterization, and study of biological activity in tissue culture.  

PubMed

A fullerene-paclitaxel conjugate has been synthesized as a slow-release drug for aerosol liposome delivery of paclitaxel for lung cancer therapy. The conjugate was designed to release paclitaxel via enzymatic hydrolysis and subsequently has shown a half-life of release of 80 min in bovine plasma. A liposome formulation of the conjugate has been prepared using dilauroylphosphatidylcholine (DLPC), and its IC50 is virtually identical to the IC50 for a paclitaxel-DLPC formulation in human epithelial lung carcinoma A549 cells. With both clinically relevant kinetics of hydrolysis and significant cytotoxicity in tissue culture, the conjugate holds promise for enhanced therapeutic efficacy of paclitaxel in vivo. PMID:16144396

Zakharian, Tatiana Y; Seryshev, Alexander; Sitharaman, Balaji; Gilbert, Brian E; Knight, Vernon; Wilson, Lon J

2005-09-14

300

Development of multiple-layer polymeric particles for targeted and controlled drug delivery  

PubMed Central

The purpose of this work was to develop multilayered particles consisting of a magnetic core and two encompassing shells made up of poly (N-isopropylacrylamide) (PNIPAAm) and poly(d,l-lactide-co-glycolide) (PLGA) for targeted and controlled drug delivery. Transmission electron microscopy confirmed that multilayered particles were obtained with PNIPAAm magnetic nanoparticles embedded within the PLGA shell. Factorial analysis studies also showed that the particle size was inversely proportional to the surfactant concentration and sonication power and directly proportional to the PLGA concentration. Drug-release results demonstrated that these multilayer particles produced an initial burst release and a subsequent sustained release of both bovine serum albumin (BSA) and curcumin loaded into the core and shell of the particle, respectively. BSA release was also affected by changes in temperature. In conclusion, our results indicate that the multilayered magnetic particles could be synthesized and used for targeted and controlled delivery of multiple drugs with different release mechanisms.

Koppolu, Bhanuprasanth; Rahimi, Maham; Nattama, Sivaniarvindpriya; Wadajkar, Aniket; Nguyen, Kytai Truong

2010-01-01

301

Nanotechnology in the targeted drug delivery for bone diseases and bone regeneration  

PubMed Central

Nanotechnology is a vigorous research area and one of its important applications is in biomedical sciences. Among biomedical applications, targeted drug delivery is one of the most extensively studied subjects. Nanostructured particles and scaffolds have been widely studied for increasing treatment efficacy and specificity of present treatment approaches. Similarly, this technique has been used for treating bone diseases including bone regeneration. In this review, we have summarized and highlighted the recent advancement of nanostructured particles and scaffolds for the treatment of cancer bone metastasis, osteosarcoma, bone infections and inflammatory diseases, osteoarthritis, as well as for bone regeneration. Nanoparticles used to deliver deoxyribonucleic acid and ribonucleic acid molecules to specific bone sites for gene therapies are also included. The investigation of the implications of nanoparticles in bone diseases have just begun, and has already shown some promising potential. Further studies have to be conducted, aimed specifically at assessing targeted delivery and bioactive scaffolds to further improve their efficacy before they can be used clinically.

Gu, Wenyi; Wu, Chengtie; Chen, Jiezhong; Xiao, Yin

2013-01-01

302

Near-Infrared Light-Responsive Core-Shell Nanogels for Targeted Drug Delivery  

PubMed Central

A near-infrared light-responsive drug delivery platform based on Au-Ag-nanorods (Au-Ag NRs) coated with DNA-crosslinked polymeric shells was constructed. DNA complementarity has been applied to develop a polyacrylamide-based sol-gel transition system to encapsulate anticancer drugs into the gel scaffold. The Au-Ag NR based nanogels can also be readily functionalized with targeting moieties, such as aptamers, for specific recognition of tumor cells. When exposed to NIR irradiation, the photothermal effect of the Au-Ag NRs leads to a rapid rise in the temperature of the surrounding gel, resulting in the fast release of the encapsulated payload with high controllability. In vitro study confirmed that aptamer functionalized nanogels can be used as drug carriers feasible for targeted drug delivery with remote control capability by NIR light with high spatial/temporal resolution.

Kang, Huaizhi; Trondoli, Anna Carolina; Zhu, Guizhi; Chen, Yan; Chang, Ya-Jen; Liu, Haipeng; Huang, Yu-Fen; Zhang, Xiaoling; Tan, Weihong

2011-01-01

303

Hyaluronic acid–polyethyleneimine conjugate for target specific intracellular delivery of siRNA  

Microsoft Academic Search

A novel target specific small interfering RNA (siRNA) delivery system was successfully developed using polyethyleneimine (PEI)-hyaluronic acid (HA) conjugate. Anti-PGL3-Luc siRNA was used as a model system suppressing the PGL3-Luc gene expression. The siRNA\\/ PEI-HA complex with an average size of ca. 21 nm appeared to be formed by electrostatic interaction between the negatively charged siRNA and the positively charged

Ge Jiang; Jiseok Kim; Ki Su Kim; Eun Ju Oh; Hyungu Kang; Su-Eun Han; Yu-Kyoung Oh; Tae Gwan Park; Sei Kwang Hahn

2008-01-01

304

Gene therapy for heart disease: molecular targets, vectors and modes of delivery to myocardium.  

PubMed

Despite the numerous hurdles that gene therapy has encountered along the way, clinical trials over the last few years are showing promising results in many fields of medicine, including cardiology, where many targets are moving toward clinical development. In this review, the authors discuss the current state of the art in terms of clinical and preclinical development. They also examine vector technology and available vector-delivery strategies. PMID:23984926

Scimia, Maria Cecilia; Cannavo, Alessandro; Koch, Walter J

2013-08-01

305

Attempt for liver-targeted delivery of antisense oligonucleotides by cholesterol modification and oral administration  

Microsoft Academic Search

Antisense oligonucleotides (ODNs) are promising anti-viral and anti-tumor therapeutical agents. Liver-targeted delivery of ODNs was studied by oral administration of cholesterol-modified phosphorothioate ODNs (Chol-S-ODNs). Cholesterol modification predominantly accelerated the uptake of ODNs by the rat intestine epithelial cell line IEC-6 and the human hepatoma cell line PLC\\/PRF\\/5. Pravastatin and chylomicron enhanced the uptake by PLC\\/PRF\\/5 cells. Antisense Chol-S-ODNs complementary to

Yasuyuki Okamoto; Hiroshi Nakano

1999-01-01

306

A novel HBV antisense RNA gene delivery system targeting hepatocellular carcinoma  

Microsoft Academic Search

AIM: To construct a novel HBV antisense RNA delivery system targeting hapatocellular carcinoma and study its inhibitory effect in vitro and in vivo. METHODS: GE7,a 16-peptide specific to EGFR, and HA20, a homologue of N-terminus of haemagglutinin of influenza viral envelope protein, were synthesized and conjugated with polylysin. The above conjugates were organized into the pEBAF-as-preS2, a hepatocarcinoma specific HBV

Chun-Hong Ma; Wen-Sheng Sun; Pei-Kun Tian; Li-Fen Gao; Su-Xia Liu; Xiao-Yan Wang; Li-Ning Zhang; Ying-Lin Cao; Li-Hui Han; Xiao-Hong Liang

307

In Vivo PEG-Modification of Vascular Surfaces for Targeted Delivery  

PubMed Central

Objective Thrombosis and restenosis remain problematic for many intravascular procedures. Previously, it has been demonstrated that modifying an injured vascular surface with a protein-reactive polymer could block undesirable platelet deposition. As an added benefit, it would be advantageous if one could target therapeutics to the injured site. This study investigates a site-specific delivery system to target microspheres to vascular surfaces modified with a reactive polyethylene glycol tagged with biotin. Methods Rabbit femoral arteries were injured with a 2F embolectomy catheter. Modification of the vascular surface was achieved using a channeled balloon catheter or small diameter tube. Microspheres were injected intravenously through catheterization of the ear vein. Polymer modification on the injured surface and delivery of microspheres was quantified using epi-fluorescence microscopy at 0, 24, 48, and 72 h. Results Polymer modification of the vascular surface could be achieved using a channeled drug delivery catheter or small diameter tube with similar results. Maximum polymer coverage occurred at 0 h and decreased to 85% maximal at 24 h, 72% at 48 h, and 67% at 72 h. The initial number of microspheres per mm2 binding to modified, injured arteries was 304 versus 141 for the unmodified, damaged control (P < .01). At subsequent times, the number of adherent microspheres to modified, injured arteries decreased by 50%, 70%, and 84% at 24, 48, and 72 h, respectively; while non-specific binding to unmodified, injured arteries quickly decreased by 93%. Initial microsphere binding to modified, healthy arteries was 153 microspheres/mm2 as opposed to 26 for the unmodified, healthy controls (P < .01). Conclusions Chemical modification of injured vessels following intravascular procedures can be readily accomplished in vivo to create a substrate for targeted delivery systems. As a proof of concept, targeted microspheres preferentially adhered to polymer-modified surfaces as opposed to injured, unmodified or healthy vascular surfaces.

Deglau, Timothy E.; Maul, Timothy M.; Villanueva, Flordeliza S.; Wagner, William R.

2011-01-01

308

Enhanced Prospects for Drug Delivery and Brain Targeting by the Choroid Plexus–CSF Route  

Microsoft Academic Search

The choroid plexus (CP), i.e., the blood–cerebrospinal fluid barrier (BCSFB) interface, is an epithelial boundary exploitable for drug delivery to brain. Agents transported from blood to lateral ventricles are convected by CSF volume transmission (bulk flow) to many periventricular targets. These include the caudate, hippocampus, specialized circumventricular organs, hypothalamus, and the downstream pia–glia and arachnoid membranes. The CSF circulatory system

Conrad E. Johanson; John A. Duncan; Edward G. Stopa; Andrew Baird

2005-01-01

309

Design and development of hydrogel beads for targeted drug delivery to the colon  

Microsoft Academic Search

The purpose of this research was to develop and evaluate a multiparticulate system of chitosan hydrogel beads exploiting pH-sensitive\\u000a property and specific biodegradability for colon-targeted delivery of satranidazole. Chitosan hydrogel beads were prepared\\u000a by the cross-linking method followed by enteric coating with Eudragit S100. All formulations were evaluated for particle size,\\u000a encapsulation efficiency, swellability, and in vitro drug release. The

Sanjay K. Jain; Anekant Jain; Yashwant Gupta; Manisha Ahirwar

2007-01-01

310

Paclitaxel uptake and transport in Taxus cell suspension cultures  

PubMed Central

The transport of paclitaxel in Taxus canadensis suspension cultures was studied with a fluorescence analogue of paclitaxel (Flutax-2®) in combination with flow cytometry detection. Experiments were carried out using both isolated protoplasts and aggregated suspension cell cultures. Flutax-2® was shown to be greater than 90% stable in Taxus suspension cultures over the required incubation time (24 hours). Unlabeled paclitaxel was shown to inhibit the cellular uptake of Flutax-2®, although structurally similar taxanes such as cephalomannine, baccatin III, and 10-deacetylbaccatin III did not inhibit Flutax-2® uptake. Saturation kinetics of Flutax-2® uptake was demonstrated. These results indicate the presence of a specific transport system for paclitaxel. Suspension cells elicited with methyl jasmonate accumulated 60% more Flutax-2® than unelicited cells, possibly due to an increased cellular storage capacity following methyl jasmonate elicitation. The presence of a specific mechanism for paclitaxel transport is an important first result that will provide the basis of more detailed studies as well as the development of targeted strategies for increased paclitaxel secretion to the extracellular medium.

Naill, Michael C.; Kolewe, Martin E.; Roberts, Susan C.

2012-01-01

311

Nucleolin Targeting AS1411 Modified Protein Nanoparticle for Antitumor Drugs Delivery.  

PubMed

Over recent years, cell surface nucleolin as an anticancer target has attracted many researchers' attentions. To improve the antitumor efficacy, we developed a nucleolin targeted protein nanoparticle (NTPN) delivery system in which human serum albumin (HSA) was used as drug carrier and a DNA aptamer named AS1411, which had high affinity to nucleolin, was used as a bullet. The HSA nanoparticles (NPs-PTX) were fabricated by a novel self-assembly method and then modified with AS1411 (Apt-NPs-PTX). The resulted Apt-NPs-PTX were spherical. Compared with NPs-PTX, the uptake of Apt-NPs-PTX displayed a significant increase in MCF-7 cells while there was a decrease in nontumor cell lines such as MCF-10A and 3T3 cells. In a cytotoxic study, Apt-NPs-PTX displayed an enhanced cytotoxicity in MCF-7 tumor cells while there was almost no cytotoxicity in MCF-10A cells. Endostatin, a nucleolin inhibitor, could significantly decrease the internalization of Apt-NPs-PTX, suggesting nucleolin mediates the transmembrane process of Apt-NPs-PTX. Therefore, the AS1411 modified NTPN delivery system might be a promising targeted drug delivery system. PMID:23679916

Wu, Jinhui; Song, Chenchen; Jiang, Chenxiao; Shen, Xin; Qiao, Qian; Hu, Yiqiao

2013-08-28

312

N-acetylgalactosamine functionalized mixed micellar nanoparticles for targeted delivery of siRNA to liver.  

PubMed

Due to its efficient and specific gene silencing ability, RNA interference has shown great potential in the treatment of liver diseases. However, achieving in vivo delivery of siRNA to critical liver cells remains the biggest obstacle for this technique to be a real clinic therapeutic modality. Here, we describe a promising liver targeting siRNA delivery system based on N-acetylgalactosamine functionalized mixed micellar nanoparticles (Gal-MNP), which can efficiently deliver siRNA to hepatocytes and silence the target gene expression after systemic administration. The Gal-MNP were assembled in aqueous solution from mixed N-acetylgalactosamine functionalized poly(ethylene glycol)-b-poly(?-caprolactone) and cationic poly(?-caprolactone)-b-poly(2-aminoethyl ethylene phosphate) (PCL-b-PPEEA); the properties of nanoparticles, including particle size, zeta potential and the density of poly(ethylene glycol) could be easily regulated. The hepatocyte-targeting effect of Gal-MNP was demonstrated by significant enriching of fluorescent siRNA in primary hepatocytes in vitro and in vivo. Successful down-regulation of liver-specific apolipoprotein B (apoB) expression was achieved in mouse liver, at both the transcriptional and protein level, following intravenous injection of Gal-MNP/siapoB to BALB/c mice. Systemic delivery of Gal-MNP/siRNA did not induce the innate immune response or positive hepatotoxicity. The results of this study suggested therapeutic potential for the Gal-MNP/siRNA system in liver disease. PMID:23266452

Wang, Hong-Xia; Xiong, Meng-Hua; Wang, Yu-Cai; Zhu, Jing; Wang, Jun

2012-12-20

313

Tumor Delivery of Chemotherapy Combined with Inhibitors of Angiogenesis and Vascular Targeting Agents  

PubMed Central

Numerous angiogenesis-vascular targeting agents have been admitted to the ranks of cancer therapeutics; most are used in polytherapy regimens. This review looks at recent progress and our own preclinical experience in combining angiogenesis inhibitors, mainly acting on VEGF/VEGFR pathways, and vascular targeting agents with conventional chemotherapy, discussing the factors that determine the outcome of these treatments. Molecular and morphological modifications of the tumor microenvironment associated with drug distribution and activity are reviewed. Modalities to improve drug delivery and strategies for optimizing combination therapy are examined.

Cesca, Marta; Bizzaro, Francesca; Zucchetti, Massimo; Giavazzi, Raffaella

2013-01-01

314

Development of Multifunctional Nanoparticles for Targeted Drug Delivery and Non-invasive Imaging of Therapeutic Effect  

PubMed Central

Nanotechnology is a multidisciplinary scientific field undergoing explosive development. Nanometer-sized particles offer novel structural, optical and electronic properties that are not attainable with individual molecules or bulk solids. Advances in nanomedicine can be made by engineering biodegradable nanoparticles such as magnetic iron oxide nanoparticles, polymers, dendrimers and liposomes that are capable of targeted delivery of both imaging agents and anticancer drugs. This leads toward the concept and possibility of personalized medicine for the potential of early detection of cancer lesions, determination of molecular signatures of the tumor by non-invasive imaging and, most importantly, molecular targeted cancer therapy. Increasing evidence suggests that the nanoparticles, whose surface contains a targeting molecule that binds to receptors highly expressed in tumor cells, can serve as cancer image contrast agents to increase sensitivity and specificity in tumor detection. In comparison with other small molecule contrast agents, the advantage of using nanoparticles is their large surface area and the possibility of surface modifications for further conjugation or encapsulation of large amounts of therapeutic agents. Targeted nanoparticles ferry large doses of therapeutic agents into malignant cells while sparing the normal healthy cells. Such multifunctional nanodevices hold the promise of significant improvement of current clinical management of cancer patients. This review explores the development of nanoparticles for enabling and improving the targeted delivery of therapeutic agents, the potential of nanomedicine, and the development of novel and more effective diagnostic and screening techniques to extend the limits of molecular diagnostics providing point-of-care diagnosis and more personalized medicine.

Sajja, Hari Krishna; East, Michael P.; Mao, Hui; Wang, Andrew Y.; Nie, Shuming; Yang, Lily

2011-01-01

315

Bifunctional Coupling Agents for Radiolabeling of Biomolecules and Target-Specific Delivery of Metallic Radionuclides  

PubMed Central

Receptor-based radiopharmaceuticals are of great current interest in early molecular imaging and radiotherapy of cancers, and provide a unique tool for target-specific delivery of radionuclides to the diseased tissues. In general, a target-specific radiopharmaceutical can be divided into four parts: targeting biomolecule (BM), pharmacokinetic modifying (PKM) linker, bifunctional coupling or chelating agent (BFC), and radionuclide. The targeting biomolecule serves as a “carrier” for specific delivery of the radionuclide. PKM linkers are used to modify radiotracer excretion kinetics. BFC is needed for radiolabeling of biomolecules with a metallic radionuclide. Different radiometals have significant difference in their coordination chemistry, and require BFCs with different donor atoms and chelator frameworks. Since the radiometal chelate can have a significant impact on physical and biological properties of the target-specific radiopharmaceutical, its excretion kinetics can be altered by modifying the coordination environment with various chelators or coligand, if needed. This review will focus on the design of BFCs and their coordination chemistry with technetium, copper, gallium, indium, yttrium and lanthanide radiometals.

Liu, Shuang

2008-01-01

316

AS1411 aptamer tagged PLGA-lecithin-PEG nanoparticles for tumor cell targeting and drug delivery.  

PubMed

Liposomes and polymers are widely used drug carriers for controlled release since they offer many advantages like increased treatment effectiveness, reduced toxicity and are of biodegradable nature. In this work, anticancer drug-loaded PLGA-lecithin-PEG nanoparticles (NPs) were synthesized and were functionalized with AS1411 anti-nucleolin aptamers for site-specific targeting against tumor cells which over expresses nucleolin receptors. The particles were characterized by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The drug-loading efficiency, encapsulation efficiency and in vitro drug release studies were conducted using UV spectroscopy. Cytotoxicity studies were carried out in two different cancer cell lines, MCF-7 and GI-1 cells and two different normal cells, L929 cells and HMEC cells. Confocal microscopy and flowcytometry confirmed the cellular uptake of particles and targeted drug delivery. The morphology analysis of the NPs proved that the particles were smooth and spherical in shape with a size ranging from 60 to 110?nm. Drug-loading studies indicated that under the same drug loading, the aptamer-targeted NPs show enhanced cancer killing effect compared to the corresponding non-targeted NPs. In addition, the PLGA-lecithin-PEG NPs exhibited high encapsulation efficiency and superior sustained drug release than the drug loaded in plain PLGA NPs. The results confirmed that AS1411 aptamer-PLGA-lecithin-PEG NPs are potential carrier candidates for differential targeted drug delivery. PMID:22615073

Aravind, Athulya; Jeyamohan, Prashanti; Nair, Remya; Veeranarayanan, Srivani; Nagaoka, Yutaka; Yoshida, Yasuhiko; Maekawa, Toru; Kumar, D Sakthi

2012-06-01

317

Preparation, characterization, cytotoxicity and drug release behavior of liposome-enveloped paclitaxel/Fe3O4 nanoparticles.  

PubMed

Phospholipid vesicles encapsulating magnetic nanoparticles (liposome complexes) have been prepared for targeting a drug to a specific organ using a magnetic force, as well as for local hyperthermia therapy. Liposome complexes are also an ideal platform for use as contrast agents of magnetic resonance imaging (MRI). We describe the preparation and characterization of liposomes containing magnetite. These liposomes were obtained by thin film hydration method and Fe3O4 nanoparticles were synthesized by coprecipitation method. They were characterized by an electrophoretic light scattering spectrophotometer, the liposome complexes were subsequently coated using chitosan. We have further investigated the ability of the above formulation for drug delivery and MRI applications. We are specifically interested in evaluating our liposome complexes for drug therapy; hence, we selected paclitaxel for the combination study. The amount of paclitaxel was measured at 227 nm using a UV-Vis spectrophotometer. Cytotoxicity of liposome complexes was treated with the various concentrations of paclitaxel in PC3 cell lines. The structure and properties of liposome complexes were analyzed by FT-IR, XRD and VSM. The particle size was analyzed by TEM and DLS. PMID:21446568

Kim, Min-Jung; Jang, Dae-Hwan; Lee, Young-In; Jung, Hyun Sook; Lee, Hak-Jong; Choa, Yong-Ho

2011-01-01

318

Pathotropic targeting advances clinical oncology: tumor-targeted localization of therapeutic gene delivery.  

PubMed

The advent of pathotropic (disease-seeking) targeting has transported genetic medicine across the threshold of history with the progressive clinical validation of Rexin-G, a tumor-targeted nanosized anti-cancer agent. Achieving noteworthy single-agent efficacy and survival benefits in otherwise intractable cancers, the molecular biotechnology platform has stimulated intense interest in the underlying mechanisms-of-action. This report exhibits the effective localization of Rexin-G nanoparticles within a metastatic liver lesion, as observed upon its surgical excision. PMID:20811660

Hall, Frederick L; Levy, John P; Reed, Rebecca A; Petchpud, Wasinee N; Chua, Victoria S; Chawla, Sant P; Gordon, Erlinda M

2010-10-01

319

Mixed micelles of PEG(2000)-DSPE and vitamin-E TPGS for concurrent delivery of paclitaxel and parthenolide: enhanced chemosenstization and antitumor efficacy against non-small cell lung cancer (NSCLC) cell lines.  

PubMed

Concurrent combination of chemotherapeutic drugs is a promising alternative to single-agent therapies in cancer. In the present study, paclitaxel and parthenolide were loaded into mixed micelles and tested against taxol sensitive (A549) and resistant (A549-T24) NSCLC cell lines. Combination chemotherapy was further evaluated by isobologram analyses and combination index calculations. Drugs were loaded into micelles by the film casting method using PEG(2000)-DSPE and vitamin E-TPGS. Micelle characterization studies included the determination of particle size, encapsulation efficiency, in vitro release kinetics, as well as 1H NMR analysis. The in vitro release of both drugs was slower from the mixed micelles, which maintained an encapsulation efficiency >95% and chemical stability over a storage period of 45 days. The IC50 of paclitaxel and parthenolide determined by MTT assay were 108.6nM and 21?M, respectively, while the combination had an IC50 of 64.15nM in A549 cells. In the taxol resistant cell lines, the IC50 values of paclitaxel and parthenolide were 233nM and 32?M, respectively, while the combination had an IC(50) of 128nM. The efficacy of paclitaxel and parthenolide against both cell lines significantly increased when the drugs were coencapsulted in mixed micelles. Mixed micelles caused 79% cell death, which was significantly higher than the 46% cell death caused by the drugs in solution against taxol sensitive cell lines. In taxol resistant cell lines, the cell death caused by mixed micelles was 70% as compared to 45% cell death caused by un-encapsulated drugs. Co-encapsulation of parthenolide with paclitaxel in mixed micelles increased the anticancer activity of paclitaxel against resistant and sensitive lung cancer cell lines. PMID:22369858

Gill, Kanwaldeep K; Kaddoumi, Amal; Nazzal, Sami

2012-02-21

320

Enhanced Affinity Bifunctional Bisphosphonates for Targeted Delivery of Therapeutic Agents to Bone  

PubMed Central

Skeletal diseases have a major impact on the worldwide population and economy. Although several therapeutic agents and treatments are available for addressing bone diseases, they are not being fully utilized because of their uptake in non-targeted sites and related side effects. Active targeting with controlled delivery is an ideal approach for treatment of such diseases. Because bisphosphonates are known to have high affinity to bone and are being widely used in treatment of osteoporosis, they are well-suited for drug targeting to bone. In this study, a targeted delivery of therapeutic agent to resorption sites and wound healing sites of bone was explored. Towards this goal, bifunctional hydrazine-bisphosphonates (HBPs), with spacers of various lengths, were synthesized and studied for their enhanced affinity to bone. Crystal growth inhibition studies showed that these HBPs have high affinity to hydroxyapatite, and HBPs with shorter spacers bind stronger than alendronate to hydroxyapatite. The HBPs did not affect proliferation of MC3T3-E1 pre-osteoblasts, did not induce apoptosis, and were not cytotoxic at the concentration range tested (10?6 - 10?4 M). Furthermore, drugs can be linked to the HBPs through a hydrazone linkage that is cleavable at the low pH of bone resorption and wound healing sites, leading to release of the drug. This was demonstrated using hydroxyapatite as a model material of bone and 4-nitrobenzaldehyde as a model drug. This study suggests that these HBPs could be used for targeted delivery of therapeutic agents to bone.

Yewle, Jivan N.; Puleo, David A.; Bachas, Leonidas G.

2011-01-01

321

Evaluation of biosafety and intracellular uptake of Cremophor EL free paclitaxel elastic liposomal formulation.  

PubMed

The present study examines the acute, sub-acute toxicity, and cytotoxicity of paclitaxel elastic liposomal formulation in comparison to a marketed Cremophor EL (polyoxyethylated castor oil):ethanol (1:1, v/v) based formulation. In the previous study, Cremophor EL free paclitaxel elastic liposomal formulation was developed and characterized. Cytotoxicity of formulation was evaluated by MTT assay using A549 cell lines. Percentage intracellular uptake of paclitaxel elastic liposomal and marketed formulation was determined using a fluorescence activating cell sorting assay (FACS) and fluorescence microscopy techniques. Single and repeated dose toxicity measurement showed no mortality, hematological, biochemical, or histopathological changes up to a dose of 120?mg/kg for paclitaxel elastic liposomal formulation, in comparison the marketed formulation showed toxicity at a dose of 40?mg/kg. Maximum tolerated dose (MTD) for paclitaxel elastic liposomal and marketed formulation was found to be 160?mg/kg and 40?mg/kg, respectively. Results of FACS analysis showed a 94.6?±?2.5% intracellular uptake of fluorescence marker acridine orange (AO) loaded in elastic liposomes; in comparison the AO solution showed only a 19.8?±?1.1% uptake. Paclitaxel elastic liposomal formulation seems to be a better alternative for safe and effective delivery of paclitaxel. This study proves the safety and higher intracellular uptake of paclitaxel elastic liposomal formulation. PMID:22074176

Utreja, Puneet; Jain, Subheet; Tiwary, A K

2011-11-10

322

Paclitaxel-incorporated nanoparticles of hydrophobized polysaccharide and their antitumor activity.  

PubMed

The aim of this study was to characterize paclitaxel-incorporated polysaccharide nanoparticles and evaluate their antitumor activity in vitro and in vivo. Pullulan was hydrophobically modified using acetic anhydride to make the paclitaxel-incorporated nanoparticles. Pullulan acetate (PA) was used to encapsulate paclitaxel using the nanoprecipitation method. The particles had spherical shapes under electron microscopy with sizes <100 nm. The sizes of paclitaxel-incorporated nanoparticles increased to >100 nm, and higher drug feeding induced higher particle size and drug content. Initial drug burst release was observed until 2 days and then the drug was continuously released over 1 week. Intrinsic cytotoxicity of empty PA nanoparticles was tested with RAW264.7 macrophage cells for biocompatibilty. The viability of RAW264.7 cells was >93% at all concentrations of empty PA nanoparticles, indicating that the PA nanoparticles are not acutely cytotoxic to normal human cells. The nanoparticles showed lower antitumor activity in vitro against HCT116 human colon carcinoma cells than that of paclitaxel itself, indicating the sustained release properties of nanoparticles. An in vivo study using HCT116 human colon carcinoma-bearing mice showed that paclitaxel-incorporated PA nanoparticles reduced tumor growth more than that of paclitaxel itself. These results indicate that PA paclitaxel-incorporated nanoparticles are a promising candidate for antitumor drug delivery. PMID:22561793

Lee, Sang Joon; Hong, Gun-Young; Jeong, Young-Il; Kang, Mi-Sun; Oh, Jong-Suk; Song, Chae-Eun; Lee, Hyun Chul

2012-04-23

323

Targeted doxorubicin delivery by chitosan-galactosylated modified polymer microbubbles to hepatocarcinoma cells.  

PubMed

Targeted drug delivery is a main issue in cancer treatment. Taking advantage of recently developed polyvinyl alcohol (PVA)-based microbubbles, which are characterized by chemical versatility of the polymeric surface thereby allowing coating with different ligands, we set up a strategy for the targeted delivery of the anticancer agent doxorubicin to hepatocarcinoma cells. Such microbubbles are exceptionally efficient ultrasound scatterers and thus represent also an option as potential ultrasound contrast agents. Moreover, the oscillation of microbubbles induced by ultrasound could contribute to favor the release of drugs allocated on shell. Specifically, PVA-based microbubbles were reacted with a galactosylated chitosan complex and loaded with doxorubicin to enable the localization and drug delivery to HepG2 hepatocarcinoma cells overexpressing asialoglycoprotein receptors. We demonstrated selectivity and greater bioadhesive properties of the functionalized microbubbles for tumor cells than to normal fibroblasts, which were influenced by the degree of galactosylation. The presence of galactosylated chitosan did not modify the rate of doxorubicin release from microbubbles, whichwas almost complete within 48h. Cellular uptake of doxorubicin loaded on functionalized microbubbles was higher in HepG2 than in normal fibroblasts, which do not over express the asialoglycoprotein receptors. In addition, doxorubicin loaded onto functionalized microbubbles fully retained its cytotoxic activity. Cells were also irradiated with ultrasound, immediately after exposure to microbubbles. An early enhancement of doxorubicin release and cellular drug uptake associated to a concomitant increase in cytotoxicity was observed in HepG2 cells. Overall, results of the study indicate that galactosylated chitosan microbubbles represent promising devices for the targeted delivery of antitumor agents to liver cancer cells. PMID:23759384

Villa, Raffaella; Cerroni, Barbara; Viganò, Lucia; Margheritelli, Silvia; Abolafio, Gabriella; Oddo, Letizia; Paradossi, Gaio; Zaffaroni, Nadia

2013-05-13

324

Dynamic PolyConjugates for targeted in vivo delivery of siRNA to hepatocytes  

PubMed Central

Achieving efficient in vivo delivery of siRNA to the appropriate target cell would be a major advance in the use of RNAi in gene function studies and as a therapeutic modality. Hepatocytes, the key parenchymal cells of the liver, are a particularly attractive target cell type for siRNA delivery given their central role in several infectious and metabolic disorders. We have developed a vehicle for the delivery of siRNA to hepatocytes both in vitro and in vivo, which we have named siRNA Dynamic PolyConjugates. Key features of the Dynamic PolyConjugate technology include a membrane-active polymer, the ability to reversibly mask the activity of this polymer until it reaches the acidic environment of endosomes, and the ability to target this modified polymer and its siRNA cargo specifically to hepatocytes in vivo after simple, low-pressure i.v. injection. Using this delivery technology, we demonstrate effective knockdown of two endogenous genes in mouse liver: apolipoprotein B (apoB) and peroxisome proliferator-activated receptor alpha (ppara). Knockdown of apoB resulted in clear phenotypic changes that included a significant reduction in serum cholesterol and increased fat accumulation in the liver, consistent with the known functions of apoB. Knockdown of ppara also resulted in a phenotype consistent with its known function, although with less penetrance than observed in apoB knockdown mice. Analyses of serum liver enzyme and cytokine levels in treated mice indicated that the siRNA Dynamic PolyConjugate was nontoxic and well tolerated.

Rozema, David B.; Lewis, David L.; Wakefield, Darren H.; Wong, So C.; Klein, Jason J.; Roesch, Paula L.; Bertin, Stephanie L.; Reppen, Tom W.; Chu, Qili; Blokhin, Andrei V.; Hagstrom, James E.; Wolff, Jon A.

2007-01-01

325

Real-time PCR targeting the sip gene for detection of group B streptococcus colonization in pregnant women at delivery  

Microsoft Academic Search

Group B streptococcus (GBS) is an important aetiological agent of serious neonatal infections. A rapid and sensitive method for the detection of GBS colonization in pregnant women at delivery could make intrapartum screening for GBS possible. A real-time PCR method targeting the sip gene of GBS in pregnant women at delivery has been evaluated. The performance of the real-time PCR

Hakon Bergseng; Lars Bevanger; Marite Rygg; Kare Bergh

2007-01-01

326

Dendrimer-triglycine-EGF nanoparticles for tumor imaging and targeted nucleic acid and drug delivery.  

PubMed

We designed an epidermal growth factor (EGF)-containing polyamidoamine (PAMAM) Generation 4 dendrimer vector labeled with quantum dots for targeted imaging and nucleic acid delivery. (1)H NMR, SDS-PAGE, and Western blotting were applied to characterize the synthesized G4.0-GGG-EGF nanoparticles. Targeting efficiency, cell viability, proliferation, and intracellular signal transduction were evaluated using HN12, NIH3T3, and NIH3T3/EGFR cells. We found that EGF-conjugated dendrimers did not stimulate growth of EGFR-expressing cells at the selected concentration. Consistent with this, minimal stimulation of post-receptor signaling pathways was observed. These nanoparticles can localize within cells that express the EGFR in a receptor-dependent manner, whereas uptake into cells lacking the receptor was low. A well characterized vimentin shRNA (shVIM) and yellow fluorescent protein (YFP) siRNA were used to test the delivery and transfection efficiency of the constructed targeted vector. Significant knockdown of expression was observed, indicating that this vector is useful for introduction of nucleic acids or drugs into cells by a receptor-targeted mechanism. PMID:20729136

Yuan, Quan; Lee, Eunmee; Yeudall, W Andrew; Yang, Hu

2010-08-21

327

The Targeted Intracellular Delivery of Cytochrome-C Protein to Tumors Using Lipid-Apolipoprotein Nanoparticles  

PubMed Central

Intracellular-acting therapeutic proteins offer a promising clinical alternative to extracellular-acting agents, but are limited in efficacy by their low permeability into the cell cytoplasm. We have developed a nanoparticle (NP) composed of lipid (DOTAP/DOPE) and apolipoprotein (APO A-I) to mediate the targeted delivery of intracellular-acting protein drugs to non-small cell lung tumors. NPs were produced with either GFP, a fluorescent model protein, or cytochrome C (cytC), an inducer of apoptosis in cancer cells. GFP and cytC were separately conjugated with a membrane permeable sequence (MPS) peptide and were admixed with DOPE/DOTAP nanoparticle formulations (NPs) to enable successful protein loading. Protein-loaded NPs were modified with DSPE-PEG-Anisamide to enable specific NP targeting to the tumor site in a xenograft model. The resulting particle was 20–30 nm in size and exhibited a 64–75% loading efficiency. H460 cells treated with the PEGylated MPS-cytC-NPs exhibited massive apoptosis. When MPS-GFP-NPs or MPS-cytC-NPs were intravenously administered in H460 tumor bearing mice, a specific tumor targeting effect with low NP accumulation in the liver was observed. In addition, MPS-cytC-NP treatment provoked a tumor growth retardation effect in H460 xenograft mice. We conclude that our NP enables targeted, efficacious therapeutic protein delivery for the treatment of lung cancer.

Kim, Sang Kyoon; Foote, Michael B.; Huang, Leaf

2012-01-01

328

Carrier-free, functionalized pure drug nanorods as a novel cancer-targeted drug delivery platform.  

PubMed

A one-dimensional drug delivery system (1D DDS) is highly attractive since it has distinct advantages such as enhanced drug efficiency and better pharmacokinetics. However, drugs in 1D DDSs are all encapsulated in inert carriers, and problems such as low drug loading content and possible undesirable side effects caused by the carriers remain a serious challenge. In this paper, a novel, carrier-free, pure drug nanorod-based, tumor-targeted 1D DDS has been developed. Drugs are first prepared as nanorods and then surface functionalized to achieve excellent water dispersity and stability. The resulting drug nanorods show enhanced internalization rates mainly through energy-dependent endocytosis, with the shape-mediated nanorod (NR) diffusion process as a secondary pathway. The multiple endocytotic mechanisms lead to significantly improved drug efficiency of functionalized NRs with nearly ten times higher cytotoxicity than those of free molecules and unfunctionalized NRs. A targeted drug delivery system can be readily achieved through surface functionalization with targeting group linked amphipathic surfactant, which exhibits significantly enhanced drug efficacy and discriminates between cell lines with high selectivity. These results clearly show that this tumor-targeting DDS demonstrates high potential toward specific cancer cell lines. PMID:23221098

Li, Yanan; Yang, Yinlong; An, Feifei; Liu, Zhuang; Zhang, Xiujuan; Zhang, Xiaohong

2012-12-05

329

Targeted delivery of antibiotics to intracellular chlamydial infections using PLGA nanoparticles.  

PubMed

Chlamydia trachomatis and Chlamydia pneumoniae are intracellular bacterial pathogens that have been shown to cause, or are strongly associated with, diverse chronic diseases. Persistent infections by both organisms are refractory to antibiotic therapy. The lack of therapeutic efficacy results from the attenuated metabolic rate of persistently infecting chlamydiae in combination with the modest intracellular drug concentrations achievable by normal delivery of antibiotics to the inclusions within which chlamydiae reside in the host cell cytoplasm. In this research, we evaluated whether nanoparticles formulated using the biodegradable poly(d-L-lactide-co-glycolide) (PLGA) polymer can enhance the delivery of antibiotics to the chlamydial inclusion complexes. We initially studied the trafficking of PLGA nanoparticles in Chlamydia-infected cells. We then evaluated nanoparticles for the delivery of antibiotics to the inclusions. Intracellular trafficking studies show that PLGA nanoparticles efficiently concentrate in inclusions in both acutely and persistently infected cells. Further, encapsulation of rifampin and azithromycin antibiotics in PLGA nanoparticles enhanced the effectiveness of the antibiotics in reducing microbial burden. Combination of rifampin and azithromycin was more effective than the individual drugs. Overall, our studies show that PLGA nanoparticles can be effective carriers for targeted delivery of antibiotics to intracellular chlamydial infections. PMID:21652065

Toti, Udaya S; Guru, Bharath R; Hali, Mirabela; McPharlin, Christopher M; Wykes, Susan M; Panyam, Jayanth; Whittum-Hudson, Judith A

2011-06-08

330

Cargo-towing fuel-free magnetic nanoswimmers for targeted drug delivery.  

PubMed

Fuel-free nanomotors are essential for future in-vivo biomedical transport and drug-delivery applications. Herein, the first example of directed delivery of drug-loaded magnetic polymeric particles using magnetically driven flexible nanoswimmers is described. It is demonstrated that flexible magnetic nickel-silver nanoswimmers (5-6 ?m in length and 200 nm in diameter) are able to transport micrometer particles at high speeds of more than 10 ?m s(-1) (more than 0.2 body lengths per revolution in dimensionless speed). The fundamental mechanism of the cargo-towing ability of these magnetic (fuel-free) nanowire motors is modelled, and the hydrodynamic features of these cargo-loaded motors discussed. The effect of the cargo size on swimming performance is evaluated experimentally and compared to a theoretical model, emphasizing the interplay between hydrodynamic drag forces and boundary actuation. The latter leads to an unusual increase of the propulsion speed at an intermediate particle size. Potential applications of these cargo-towing nanoswimmers are demonstrated by using the directed delivery of drug-loaded microparticles to HeLa cancer cells in biological media. Transport of the drug carriers through a microchannel from the pick-up zone to the release microwell is further illustrated. It is expected that magnetically driven nanoswimmers will provide a new approach for the rapid delivery of target-specific drug carriers to predetermined destinations. PMID:22174121

Gao, Wei; Kagan, Daniel; Pak, On Shun; Clawson, Corbin; Campuzano, Susana; Chuluun-Erdene, Erdembileg; Shipton, Erik; Fullerton, Eric E; Zhang, Liangfang; Lauga, Eric; Wang, Joseph

2011-12-15

331

Targeted Delivery of Antibiotics to Intracellular Chlamydial Infections using PLGA Nanoparticles  

PubMed Central

Chlamydia trachomatis and C pneumoniae are intracellular bacterial pathogens that have been shown to cause, or are strongly associated with, diverse chronic diseases. Persistent infections by both organisms are refractory to antibiotic therapy. The lack of therapeutic efficacy results from the attenuated metabolic rate of persistently infecting chlamydiae in combination with the modest intracellular drug concentrations achievable by normal delivery of antibiotics to the inclusions within which chlamydiae reside in the host cell cytoplasm. In this research, we evaluated whether nanoparticles formulated using the biodegradable poly(d-L-lactide-co-glycolide) (PLGA) polymer can enhance the delivery of antibiotics to the chlamydial inclusion complexes. We initially studied the trafficking of PLGA nanoparticles in Chlamydia-infected cells. We then evaluated nanoparticles for the delivery of antibiotics to the inclusions. Intracellular trafficking studies show that PLGA nanoparticles efficiently concentrate in inclusions in both acutely and persistently infected cells. Further, encapsulation of rifampin and azithromycin antibiotics in PLGA nanoparticles enhanced the effectiveness of the antibiotics in reducing microbial burden. Combination of rifampin and azithromycin was more effective than the individual drugs. Overall, our studies show that PLGA nanoparticles can be effective carriers for targeted delivery of antibiotics to intracellular chlamydial infections.

Toti, Udaya S.; Guru, Bharath R.; Hali, Mirabela; McPharlin, Christopher; Wykes, Susan M.; Panyam, Jayanth; Whittum-Hudson, Judith A.

2011-01-01

332

Colon-targeted quercetin delivery using natural polymer to enhance its bioavailability.  

PubMed

The aim of the present study is to develop a polymer (Guar Gum)-based matrix tablet (using quercetin as a model drug) with sufficient mechanical strength, and promising in vitro mouth-to-colon release profile. By definition, an oral colonic delivery system should retard drug release in the stomach and small intestine, and allow complete release in the colon. By drug delivery to the colon would therefore ensure direct treatment at the disease site, lower dosing, and fewer systemic side effects. Quercetin is antioxidant in nature and used to treat colon cancer, but they have poor absorption in the upper part of the gastrointestinal tract (GIT). As a site for drug delivery, the colon offers a near neutral pH, reduced digestive enzymatic activity, a long transit time, and an increased responsiveness to absorption enhancers. By achieving a colon-targeted drug delivery system, the absorption of quercetin may be increased, which leads to better bioactivity in fewer doses. PMID:21731393

Singhal, Anil; Jain, H; Singhal, Vipin; Elias, Edwin J; Showkat, Ahmad

2011-01-01

333

Cell-specific targeting strategies for electroporation-mediated gene delivery in cells and animals.  

PubMed

The use of electroporation to facilitate gene transfer is an extremely powerful and useful method for both in vitro and in vivo applications. One of its great strengths is that it induces functional destabilization and permeabilization of cell membranes throughout a tissue leading to widespread gene transfer to multiple cells and cell types within the electric field. While this is a strength, it can also be a limitation in terms of cell-specific gene delivery. The ability to restrict gene delivery and expression to particular cell types is of paramount importance for many types of gene therapy, since ectopic expression of a transgene could lead to deleterious host inflammatory responses or dysregulation of normal cellular functions. At present, there are relatively few ways to obtain cell-specific targeting of nonviral vectors, molecular probes, small molecules, and imaging agents. We have developed a novel means of restricting gene delivery to desired cell types based on the ability to control the transport of plasmids into the nuclei of desired cell types. In this article, we discuss the mechanisms of this approach and several applications in living animals to demonstrate the benefits of the combination of electroporation and selective nuclear import of plasmids for cell-specific gene delivery. PMID:23525583

Dean, David A

2013-03-24

334

Ultrasound-enhanced delivery of targeted echogenic liposomes in a novel ex vivo mouse aorta model  

PubMed Central

The goal of this study was to determine whether targeted, Rhodamine-labeled echogenic liposomes (Rh-ELIP) containing nanobubbles could be delivered to the arterial wall, and whether 1 MHz continuous wave ultrasound would enhance this delivery profile. Aortae excised from apolipoprotein-E-deficient (n = 8) and wild-type (n = 8) mice were mounted in a pulsatile flow system through which Rh-ELIP were delivered in a stream of bovine serum albumin. Half the aortae from each group were treated with 1-MHz continuous wave ultrasound at 0.49 MPa peak-to-peak pressure, and half underwent sham exposure. Ultrasound parameters were chosen to promote stable cavitation and avoid inertial cavitation. A broadband hydrophone was used to monitor cavitation activity. After treatment, aortic sections were prepared for histology and analyzed by an individual blinded to treatment conditions. Delivery of Rh-ELIP to the vascular endothelium was observed, and subendothelial penetration of Rh-ELIP was present in five of five ultrasound-treated aortae and was absent in those not exposed to ultrasound. However, the degree of penetration in the ultrasound-exposed aortae was variable. There was no evidence of ultrasound-mediated tissue damage in any specimen. Ultrasound-enhanced delivery within the arterial wall was demonstrated in this novel model, which allows quantitative evaluation of therapeutic delivery.

Hitchcock, Kathryn E.; Caudell, Danielle N.; Sutton, Jonathan T.; Klegerman, Melvin E.; Vela, Deborah; Pyne-Geithman, Gail J.; Abruzzo, Todd; Cyr, Peppar E. P.; Geng, Yong-Jian; McPherson, David D.; Holland, Christy K.

2010-01-01

335

Hyaluronic acid modified mesoporous silica nanoparticles for targeted drug delivery to CD44-overexpressing cancer cells.  

PubMed

In this paper, a targeted drug delivery system has been developed based on hyaluronic acid (HA) modified mesoporous silica nanoparticles (MSNs). HA-MSNs possess a specific affinity to CD44 over-expressed on the surface of a specific cancer cell line, HCT-116 (human colon cancer cells). The cellular uptake performance of fluorescently labelled MSNs with and without HA modification has been evaluated by confocal microscopy and fluorescence-activated cell sorter (FACS) analysis. Compared to bare MSNs, HA-MSNs exhibit a higher cellular uptake via HA receptor mediated endocytosis. An anticancer drug, doxorubicin hydrochloride (Dox), has been loaded into MSNs and HA-MSNs as drug delivery vehicles. Dox loaded HA-MSNs show greater cytotoxicity to HCT-116 cells than free Dox and Dox-MSNs due to the enhanced cell internalization behavior of HA-MSNs. It is expected that HA-MSNs have a great potential in targeted delivery of anticancer drugs to CD44 over-expressing tumors. PMID:23076766

Yu, Meihua; Jambhrunkar, Siddharth; Thorn, Peter; Chen, Jiezhong; Gu, Wenyi; Yu, Chengzhong

2012-10-18

336

Targeted delivery of oligonucleotides into tumor-associated macrophages for cancer immunotherapy.  

PubMed

Tumor-associated macrophages (TAMs) have been proven to be a driving force in the initiation, proliferation, metastasis and angiogenesis of various tumors. Specifically, alterations in the functions of TAMs exhibited inhibitory effects on tumor growth. However, there is currently no research being conducted on the targeting delivery of drugs into TAMs for cell-specific tumor immunotherapy. In the present study, we developed a TAMs targeted delivery system that is triggered by the acidic microenvironment in the tumor to release a TAMs-recognizing nano-complex loaded with oligonucleotides. By using this system, we demonstrated a significant anti-tumor effect of an oligonucleotide combination of CpG oligonucleotide, anti-IL-10 and anti-IL-10 receptor oligonucleotides. These nucleic acid drugs delivered by the delivery system accumulated in the TAMs of an allograft hepatoma murine model by intravenous injection, suppressed the pro-tumor functions and stimulated the anti-tumor activities of TAMs. More importantly, the nucleic acid drug-based immune-regulation was restricted to the tumor microenvironment and did not cause an upregulation of serum inflammatory cytokines. Our present study provides an effective therapeutic strategy for regulating cell-specific functions using nucleic acid drugs. PMID:22119956

Huang, Zhen; Zhang, Zhengping; Jiang, Yucui; Zhang, Dachuan; Chen, Jiangning; Dong, Lei; Zhang, Junfeng

2011-11-18

337

Mechanistic study of IR-780 dye as a potential tumor targeting and drug delivery agent.  

PubMed

IR-780 iodide, a near-infrared fluorescent heptamethine dye, has been recently characterized to exhibit preferential accumulation property in the mitochondria of tumor cells. In this study, we investigated the possible mechanisms for its tumor selective activity and its potential as a drug delivery carrier. Results showed that the energy-dependent uptake of IR-780 iodide into the mitochondria of tumor cells was affected by glycolysis and plasma membrane potential. Moreover, OATP1B3 subtype of organic anion transporter peptides (OATPs) may play a dominant role in the transportation of IR-780 iodide into tumor cells, while cellular endocytosis, mitochondrial membrane potential and the ATP-binding cassette transporters did not show significant influence to its accumulation. We further evaluated the potential of IR-780 iodide as a drug delivery carrier by covalent conjugation of IR-780 with nitrogen mustard (IR-780NM). In vivo imaging showed that IR-780NM remained the tumor targeting property, indicating that IR-780 iodide could be potentially applied as a drug delivery agent for cancer targeted imaging and therapy. PMID:24148240

Zhang, Erlong; Luo, Shenglin; Tan, Xu; Shi, Chunmeng

2013-10-20

338

Peptide-conjugated PAMAM for targeted doxorubicin delivery to transferrin receptor overexpressed tumors.  

PubMed

The purpose of this work was to evaluate the potential of HAIYPRH (T7) peptide as a ligand for constructing tumor-targeting drug delivery systems. T7 could target to transferrin-receptor (TfR) through a cavity on the surface of TfR and then transport into cells via endocytosis with the help of transferrin (Tf). In this study, T7-conjugated poly(ethylene glycol) (PEG)-modified polyamidoamine dendrimer (PAMAM) (PAMAM-PEG-T7) was successfully synthesized and further loaded with doxorubicin (DOX), formulating PAMAM-PEG-T7/DOX nanoparticles (NPs). In vitro, almost 100% of DOX was released during 2 h in pH 5.5, while only 55% of DOX was released over 48 h in pH 7.4. The cellular uptake of DOX could be significantly enhanced when treated with T7-modified NPs in the presence of Tf. Also, the in vitro antitumor effect was enhanced markedly. The IC(50) of PAMAM-PEG-T7/DOX NPs with Tf was 231.5 nM, while that of NPs without Tf was 676.7 nM. T7-modified NPs could significantly enhance DOX accumulation in the tumor by approximately 1.7-fold compared to that of unmodified ones and by approximately 5.3-fold compared to that of free DOX. For in vivo antitumor studies, tumor growth of mice treated with PAMAM-PEG-T7/DOX NPs was significantly inhibited compared to that of mice treated with PAMAM-PEG/DOX NPs and saline. The study provides evidence that PAMAM-PEG-T7 can be applied as a potential tumor-targeting drug delivery system. T7 may be a promising ligand for targeted drug delivery to the tumor. PMID:20857964

Han, Liang; Huang, Rongqin; Liu, Shuhuan; Huang, Shixian; Jiang, Chen

2010-10-14

339

Design and fabrication of magnetic nanoparticles for targeted drug delivery and imaging  

PubMed Central

Magnetic nanoparticles (MNPs) represent a class of non-invasive imaging agents that have been developed for magnetic resonance (MR) imaging. These MNPs have traditionally been used for disease imaging via passive targeting, but recent advances have opened the door to cellular-specific targeting, drug delivery, and multi-modal imaging by these nanoparticles. As more elaborate MNPs are envisioned, adherence to proper design criteria (e.g. size, coating, molecular functionalization) becomes even more essential. This review summarizes the design parameters that affect MNP performance in vivo, including the physicochemical properties and nanoparticle surface modifications, such as MNP coating and targeting ligand functionalizations that can enhance MNP management of biological barriers. A careful review of the chemistries used to modify the surfaces of MNPs is also given, with attention paid to optimizing the activity of bound ligands while maintaining favorable physicochemical properties.

Veiseh, Omid; Gunn, Jonathan; Zhang, Miqin

2009-01-01

340

Improving oncology outcomes through targeted therapeutics will require electronic delivery systems.  

PubMed

Typically, chemotherapy selection takes into account patient demographic data, including disease symptoms, family history, environmental factors and concurrent medications. Although validated and approved genomics tests are available for targeted therapeutics, a major challenge facing healthcare is the ability to process the genomic data in the patient's context and to return clinically interpretable dosing guidance to the physician in a realistic time frame. Delivery of these targeted therapeutics, made possible by clinical decision support systems connected to an electronic health record may help drive both the acceptance and adaptation of an electronic health record system, as well as provide personalized information at point-of-care, as part of the routine workflow. The realization of targeted therapeutics will depend on the concerted efforts of stakeholder groups as they address political, ethical, socioeconomical and technical challenges to achieve personalized medicine adoption through real-world implementation. PMID:21568680

van Rooij, Tibor; Marsh, Sharon

2011-05-01

341

Comparison of two kinds of nanomedicine for targeted gene therapy: premodified or postmodified gene delivery systems  

PubMed Central

Background The applications of ligand-polyethylene glycol (PEG)-modified nanocarriers have now emerged, as well as recognized strategies to provide the vectors with active targeting properties. In this research, premodification and postmodification were compared using the same ligand, ie, a novel conjugated mannan-containing PEG and L-?-phosphatidylethanolamine (PE). Methods Premodified and postmodified solid lipid nanoparticles were prepared and the characteristics of the two kinds of vehicles were evaluated. The modified vectors were then administered intravenously to rats and the in vivo targeting behavior of the complexes was investigated in liver macrophages. Results By carefully formulating the carriers with an optimal ratio of mannan-containing PEG-PE, postmodified vehicles displayed more efficient gene expression in rat Kupffer cells both in vitro and in vivo. Conclusion Postmodified gene carriers are superior to premodified gene vectors, although the latter is also promising for targeted gene delivery. This discovery could guide our future research.

Jiang, Zhaoshun; Sun, Cong; Yin, Zhaohui; Zhou, Fang; Ge, Linfu; Liu, Ximin; Kong, Fansheng

2012-01-01

342

Mathematical Modeling and Optimization of Drug Delivery from Intratumorally Injected Microspheres  

Microsoft Academic Search

Purpose: Paclitaxel is a highly promising phase-sensitive antitumor drug that could conceivably be improved by extended lower dosing as opposed to intermittent higher dosing. Although intratumoral delivery of paclitaxel to the whole tumor at different loads and rates has already been achieved, determining an optimal release mode of paclitaxel for tumor eradication remains difficult. This study set out to rationally

Abraham Rami Tzafriri; Elyakum Itzhak Lerner; Moshe Flashner-Barak; Michael Hinchcliffe; Eli Ratner; Hanna Parnas

2005-01-01

343

A peptide-mediated targeting gene delivery system for malignant glioma cells  

PubMed Central

Glioblastoma multiforme (GBM) is the most common and malignant glioma. Although there has been considerable progress in treatment strategies, the prognosis of many patients with GBM remains poor. In this work, polyethylenimine (PEI) and the VTWTPQAWFQWV (VTW) peptide were modified and synthesized into GBM-targeting nanoparticles. The transfection efficiency of U-87 (human glioblastoma) cells was evaluated using fluorescence microscopy and flow cytometry. Cell internalization was investigated to verify the nanoparticle delivery into the cytoplasm. Results showed that the methods of polymer conjugation and the amount of VTW peptide were important factors to polymer synthesis and transfection. The PEI-VTW20 nanoparticles increased the transfection efficiency significantly. This report describes the use of VTW peptide-based PEI nanoparticles for intracellular gene delivery in a GBM cell-specific manner.

Wang, Chuanwei; Ning, Liping; Wang, Hongwei; Lu, Zaijun; Li, Xingang; Fan, Xiaoyong; Wang, Xuping; Liu, Yuguang

2013-01-01

344

Catalytic Janus motors on microfluidic chip: deterministic motion for targeted cargo delivery.  

PubMed

We fabricated self-powered colloidal Janus motors combining catalytic and magnetic cap structures, and demonstrated their performance for manipulation (uploading, transportation, delivery) and sorting of microobjects on microfluidic chips. The specific magnetic properties of the Janus motors are provided by ultrathin multilayer films that are designed to align the magnetic moment along the main symmetry axis of the cap. This unique property allows a deterministic motion of the Janus particles at a large scale when guided in an external magnetic field. The observed directional control of the motion combined with extensive functionality of the colloidal Janus motors conceptually opens a straightforward route for targeted delivery of species, which are relevant in the field of chemistry, biology, and medicine. PMID:22424213

Baraban, Larysa; Makarov, Denys; Streubel, Robert; Mönch, Ingolf; Grimm, Daniel; Sanchez, Samuel; Schmidt, Oliver G

2012-03-22

345

Tumor-targeted liposomal drug delivery mediated by a diseleno bond-stabilized cyclic peptide  

PubMed Central

Peptide ligands have played an important role in tumor-targeted drug delivery as targeting moieties. The in vivo fate of peptide-mediated drug delivery systems and the following antitumor effects may greatly depend on the stability of the peptide ligand. In the current study, a tumor-targeting cyclic peptide screened by phage display, Lyp-1 (a peptide that specifically binds to tumor and endothelial cells of tumor lymphatics in certain tumors), was structurally modified by replacement of the original intramolecular disulfide bond with a diseleno bond. The produced analog Syp-1 (seleno derivative of Lyp-1) maintained specific binding ability to the target protein p32 (Kd = 18.54 nM), which is similar to that of Lyp-1 (Kd = 10.59 nM), indicated by surface plasmon resonance assay. Compared with Lyp-1, Syp-1 showed significantly improved stability against serum. After the peptide attached onto the surface of fluorophore-encapsulating liposomes, the more efficient tumor uptake of liposomal fluorophore mediated by Syp-1 was observed. Furthermore, Syp-1 modified liposomal doxorubicin presented the most potent tumor growth inhibitory ability among all the therapeutic groups, with a low half maximal inhibitory concentration of 588 nM against MDA-MB-435 cells in vitro and a high tumor inhibition rate of 73.5% in vivo. These findings clearly indicated that Syp-1 was a stable and effective tumor targeting ligand and suggest that the sulfur-to-selenium replacement strategy may help stabilize the phage-displayed cyclic peptide containing disulfide-bond under physiological conditions and strongly support the validity of peptide-mediated drug targeting.

Li, Chong; Wang, Yixin; Zhang, Xiaolin; Deng, Li; Zhang, Yan; Chen, Zhangbao

2013-01-01

346

Poly (vinyl alcohol) hydrogels for pH dependent colon targeted drug delivery.  

PubMed

Oral drug administration is convenient with pH dependent drug delivery system since the drug has to pass through different pH environments in gastro intestinal (GI) tract. The pH dependent swelling/shrinking behavior of hydrogel drug carrier controls the drug release without affecting the function of drug. pH dependent hydrogels of poly (vinyl alcohol) (PVA) were prepared by cross linking with maleic acid (MA). The hydrogels were characterized by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, DSC, porosimetry, SEM, TEM, biocompatibility study and by measuring their swelling behavior in water, simulated gastric fluid (SGF) and intestinal fluid (SIF). Swelling of the hydrogels was found to be highest in SIF (pH: 7.5) and lowest in SGF (pH: 1.2) resembling that required in colon targeted drug delivery systems. Since the swelling behavior of the gel is pH dependent, these hydrogels were studied for colon targeted drug delivery in an in-vitro set-up resembling the condition of GI tract. The ratio of PVA and MA in the hydrogel was varied to study the effect on the drug diffusion rate. For drug delivery study, vitamin B12 and salicylic acid were used as model drugs. The hydrogel, loaded with model drugs vitamin B12 and salicylic acid also demonstrated colon specific drug release with a relatively higher drug release in SIF (pH: 7.5) than that in SGF (pH: 1.2). PMID:18592350

Basak, Piyali; Adhikari, Basudam

2008-07-01

347

A double-targeted magnetic nanocarrier with potential application in hydrophobic drug delivery.  

PubMed

A double-targeted magnetic nanocarrier based with potential applications in the delivery of hydrophobic drugs has been developed. It consists of magnetite (Fe(3)O(4)) nanoparticles encapsulated in self-assembled micelles of the amphiphilic copolymer MPEG-PLGA [methoxy poly (ethylene glycol)-poly (d,l-lactide-co-glycolide)], and was fabricated using the solvent-evaporation technique. The magnetic nanocarrier has a very stable core-shell structure and is superparamagnetic. Its cytotoxicity was evaluated using the MTT assay with three cell lines-HeLa, MCF-7, and HT1080; it exhibited no cytotoxicity against any tested line at concentrations of up to 400 ?g/mL after incubation for 24 h. Its cellular uptake was studied by Prussian blue staining and by fluorescence microscopy after encapsulating a fluorescent probe (hydrophobic quantum dots) into the nanocarrier. Finally, the magnetic targeting property of the magnetic nanocarrier was confirmed by an in vitro test. Overall, the results obtained demonstrate the potential of the double-targeted nanocarrier for the intracellular delivery of hydrophobic drugs. PMID:22088760

Ding, Guobin; Guo, Yi; Lv, Yanyun; Liu, Xiaofeng; Xu, Li; Zhang, Xuezhong

2011-10-25

348

A dual-functionally modified chitosan derivative for efficient liver-targeted gene delivery.  

PubMed

Galactosylated chitosan-hydroxypropyltrimethylammonium (gal-HTCC) was synthesized by galactosylating and quaternizing chitosan to endue chitosan with targeting specificity for potential applications as gene vectors. The composition and physicochemical properties of gal-HTCC were characterized by FT-IR, (1) H NMR, elemental analysis, X-ray diffraction, and turbidity measurement. It was found that water-soluble gal-HTCC showed a more amorphous structure than chitosan, and it also had a much better plasmid condensation capability than galactosylated chitosan. Cytotoxicity measurements revealed that gal-HTCC showed significantly lower cytotoxicity in HepG2 and HeLa cell lines compared to branched polyethylenimine (bPEI, 25 kDa) which was used as a positive control. The nanoparticles (NPs) consisted of gal-HTCC and plasmid DNA had desirable particle size (around 250 nm) with a narrow size distribution. Confocal laser scanning microscopy confirmed that NPs could be internalized and transported to the nucleus efficiently within 6 h. In vitro gene transfection results indicated that gal-HTCC had significantly higher transfection efficiency (7- to 32-fold) compared to chitosan and gal-chitosan for targetable delivery of pGL3 luciferase plasmid to HepG2, and its transfection efficiency was highly inhibited in the presence of galactose (20 mM). All these results suggest that gal-HTCC can function as a promising nonviral gene vector for efficient liver-targeted gene delivery. PMID:23203540

Xiao, Bo; Wang, Xiaoyu; Qiu, Zhiye; Ma, Jun; Zhou, Lei; Wan, Ying; Zhang, Shengmin

2012-12-03

349

Wireless capsule endoscope for targeted drug delivery: mechanics and design considerations.  

PubMed

This paper describes a platform to achieve targeted drug delivery in the next-generation wireless capsule endoscopy. The platform consists of two highly novel subsystems: one is a micropositioning mechanism which can deliver 1 ml of targeted medication and the other is a holding mechanism, which gives the functionality of resisting peristalsis. The micropositioning mechanism allows a needle to be positioned within a 22.5 ° segment of a cylindrical capsule and be extendible by up to 1.5 mm outside the capsule body. The mechanism achieves both these functions using only a single micromotor and occupying a total volume of just 200 mm (3). The holding mechanism can be deployed diametrically opposite the needle in 1.8 s and occupies a volume of just 270 mm (3). An in-depth analysis of the mechanics is presented and an overview of the requirements necessary to realize a total system integration is discussed. It is envisaged that the targeted drug delivery platform will empower a new breed of capsule microrobots for therapy in addition to diagnostics for pathologies such as ulcerative colitis and small intestinal Crohn's disease. PMID:23192476

Woods, Stephen P; Constandinou, Timothy G

2012-11-21

350

Pluronic F127 nanomicelles engineered with nuclear localized functionality for targeted drug delivery.  

PubMed

PKKKRKV (Pro-Lys-Lys-Lys-Arg-Lys-Val, PV7), a seven amino acid peptide, has emerged as one of the primary nuclear localization signals that can be targeted into cell nucleus via the nuclear import machinery. Taking advantage of chemical diversity and biological activities of this short peptide sequence, in this study, Pluronic F127 nanomicelles engineered with nuclear localized functionality were successfully developed for intracellular drug delivery. These nanomicelles with the size ~100 nm were self-assembled from F127 polymer that was flanked with two PV7 sequences at its both terminal ends. Hydrophobic anticancer drug doxorubicin (DOX) with inherent fluorescence was chosen as the model drug, which was found to be efficiently encapsulated into nanomicelles with the encapsulation efficiency at 72.68%. In comparison with the non-functionalized namomicelles, the microscopic observation reveals that PV7 functionalized nanomicelles display a higher cellular uptake, especially into the nucleus of HepG2 cells, due to the nuclear localization signal effects. Both cytotoxicity and apoptosis studies show that the DOX-loaded nanomicelles were more potent than drug nanomicelles without nuclear targeting functionality. It was thus concluded that PV7 functionalized nanomicelles could be a potentially alternative vehicle for nuclear targeting drug delivery. PMID:23623086

Li, Yong-Yong; Li, Lan; Dong, Hai-Qing; Cai, Xiao-Jun; Ren, Tian-Bin

2013-02-27

351

Phototriggerable 2?,7-Caged Paclitaxel  

PubMed Central

Three different variants of photoactivatable caged paclitaxel (PTX) have been synthesized and their bioactivity was characterized in in vitro assays and in living cells. The caged PTXs contain the photoremovable chromophore 4,5-dimethoxy-2-nitrobenzyloxycarbonyl (Nvoc) attached to position C7, C2' and to both of these positions via a carbonate bond. Single caged PTXs remained biologically active even at low dosages. Double caging was necessary in order to fully inhibit its activity and to obtain a phototriggerable PTX that can be applied successfully at commonly used concentrations. Irradiation of solutions containing the double caged PTX allowed dose-dependent delivery of functional PTX. Light-triggered stabilization of microtubule assemblies in vitro and in vivo by controlled light exposure of tubulin solutions or cell cultures containing caged PTX was demonstrated. Short light exposure under a fluorescence microscope allowed controlled delivery of free PTX during imaging.

Gropeanu, Radu A.; Baumann, Hella; Ritz, Sandra; Mailander, Volker; Surrey, Thomas; del Campo, Aranzazu

2012-01-01

352

Control of Endothelial Targeting and Intracellular Delivery of Therapeutic Enzymes by Modulating the Size and Shape of ICAM-1-targeted Carriers  

Microsoft Academic Search

Endocytosis in endothelial cells (ECs) is important for many biomedical applications, including drug delivery by nano- and microscale carriers. However, little is known about how carrier geometry influences endothelial drug targeting, intracellular trafficking, and effects. We studied this using prototype polymer carriers of various sizes (0.1–10 ?m) and shapes (spheres versus elliptical disks). Carriers were targeted to intercellular adhesion molecule

Silvia Muro; Carmen Garnacho; Julie A Champion; John Leferovich; Christine Gajewski; Edward H Schuchman; Samir Mitragotri; Vladimir R Muzykantov

2008-01-01

353

Synthetic Nano-Low Density Lipoprotein as Targeted Drug DeliveryVehicle for Glioblastoma Multiforme  

SciTech Connect

This paper discribes a synthetic low density lipoprotein(LDL) made by complexing a 29 amino acid that consists of a lipid bindingdomain and the LDL receptor binding domain with a lipid microemulsion.The nano-LDL particles were intermdiate in size between LDL and HDL andbound to LDL receptors on GBM brain tumor cells. Synthetic nano-LDLuptake by GBM cells was LDL receptor specific and dependent on cellreceptor number. It is suggested that these synthetic particles can serveas a delivery vehicle for hydophobic anti-tumor drugs by targeting theLDL receptor.

Nikanjam, Mina; Blakely, Eleanor A.; Bjornstad, Kathleen A.; Shu,Xiao; Budinger, Thomas F.; Forte, Trudy M.

2006-06-14

354

Design of an integrated hardware interface for AOSLO image capture and cone-targeted stimulus delivery  

PubMed Central

We demonstrate an integrated FPGA solution to project highly stabilized, aberration-corrected stimuli directly onto the retina by means of real-time retinal image motion signals in combination with high speed modulation of a scanning laser. By reducing the latency between target location prediction and stimulus delivery, the stimulus location accuracy, in a subject with good fixation, is improved to 0.15 arcminutes from 0.26 arcminutes in our earlier solution. We also demonstrate the new FPGA solution is capable of delivering stabilized large stimulus pattern (up to 256x256 pixels) to the retina.

Yang, Qiang; Arathorn, David W.; Tiruveedhula, Pavan; Vogel, Curtis R.; Roorda, Austin

2010-01-01

355

A pH-dependent colon targeted oral drug delivery system using methacrylic acid copolymers  

Microsoft Academic Search

Lactose-based placebo tablets were coated using various combinations of two methacrylic acid copolymers, Eudragit® L100-55 and Eudragit® S100, by spraying from aqueous systems. The Eudragit® L100-55–Eudragit® S100 combinations (w\\/w) studied were 1:0, 4:1, 3:2, 1:1, 2:3, 1:4, 1:5 and 0:1. The coated tablets were tested in vitro for their suitability for pH dependent colon targeted oral drug delivery. The same

M. Zahirul I Khan; Željko Prebeg; Nevenka Kurjakovi?

1999-01-01

356

Targeted delivery of cytokine therapy to rheumatoid tissue by a synovial targeting peptide  

PubMed Central

Objectives The synovial endothelium targeting peptide (SyETP) CKSTHDRLC has been identified previously and was shown to preferentially localise to synovial xenografts in the human/severe combined immunodeficient (SCID) mouse chimera model of rheumatoid arthritis (RA). The objective of the current work was to generate SyETP-anti-inflammatory-cytokine fusion proteins that would deliver bioactive cytokines specifically to human synovial tissue. Methods Fusion proteins consisting of human interleukin (IL)-4 linked via a matrix metalloproteinase (MMP)-cleavable sequence to multiple copies of either SyETP or scrambled control peptide were expressed in insect cells, purified by Ni-chelate chromatography and bioactivity tested in vitro. The ability of SyETP to retain bioactive cytokine in synovial but not control skin xenografts in SCID mice was determined by in vivo imaging using nano-single-photon emission computed tomography-computed tomography (nano-SPECT-CT) and measuring signal transducer and activator of transcription 6 (STAT6) phosphorylation in synovial grafts following intravenous administration of the fusion protein. Results In vitro assays confirmed that IL-4 and the MMP-cleavable sequence were functional. IL-4-SyETP augmented production of IL-1 receptor antagonist (IL-1ra) by fibroblast-like synoviocytes (FLS) stimulated with IL-1?  in a dose-dependent manner. In vivo imaging showed that IL-4-SyETP was retained in synovial but not in skin tissue grafts and the period of retention was significantly enhanced through increasing the number of SyETP copies from one to three. Finally, retention correlated with increased bioactivity of the cytokine as quantified by STAT6 phosphorylation in synovial grafts. Conclusions The present work demonstrates that SyETP specifically delivers fused IL-4 to human rheumatoid synovium transplanted into SCID mice, thus providing a proof of concept for peptide-targeted tissue-specific immunotherapy in RA. This technology is potentially applicable to other biological treatments providing enhanced potency to inflammatory sites and reducing systemic toxicity.

Wythe, Sarah E; DiCara, Danielle; Taher, Taher E I; Finucane, Ciara M; Jones, Rita; Bombardieri, Michele; Man, Y K Stella; Nissim, Ahuva; Mather, Stephen J; Chernajovsky, Yuti; Pitzalis, Costantino

2013-01-01

357

Transferrin and the transferrin receptor for the targeted delivery of therapeutic agents to the brain and cancer cells.  

PubMed

The potential use of many promising novel drugs is limited by their inability to specifically reach their site of action after intravenous administration, without secondary effects on healthy tissues. In order to remediate this problem, the protein transferrin (Tf) has been extensively studied as a targeting molecule for the transport of drug and gene delivery systems to the brain and cancer cells. A wide range of delivery approaches have been developed to target the Tf receptor and they have already improved the specific delivery of Tf-bearing therapeutic agents to their site of action. This review provides a summary of the numerous delivery strategies used to target the Tf receptor and focuses on recent therapeutic advances. PMID:23647279

Dufès, Christine; Al Robaian, Majed; Somani, Sukrut

2013-05-01

358

Paclitaxel-induced apoptosis is BAK-dependent, but BAX and BIM-independent in breast tumor.  

PubMed

Paclitaxel (Taxol)-induced cell death requires the intrinsic cell death pathway, but the specific participants and the precise mechanisms are poorly understood. Previous studies indicate that a BH3-only protein BIM (BCL-2 Interacting Mediator of cell death) plays a role in paclitaxel-induced apoptosis. We show here that BIM is dispensable in apoptosis with paclitaxel treatment using bim(-/-) MEFs (mouse embryonic fibroblasts), the bim(-/-) mouse breast tumor model, and shRNA-mediated down-regulation of BIM in human breast cancer cells. In contrast, both bak (-/-) MEFs and human breast cancer cells in which BAK was down-regulated by shRNA were more resistant to paclitaxel. However, paclitaxel sensitivity was not affected in bax(-/-) MEFs or in human breast cancer cells in which BAX was down-regulated, suggesting that paclitaxel-induced apoptosis is BAK-dependent, but BAX-independent. In human breast cancer cells, paclitaxel treatment resulted in MCL-1 degradation which was prevented by a proteasome inhibitor, MG132. A Cdk inhibitor, roscovitine, blocked paclitaxel-induced MCL-1 degradation and apoptosis, suggesting that Cdk activation at mitotic arrest could induce subsequent MCL-1 degradation in a proteasome-dependent manner. BAK was associated with MCL-1 in untreated cells and became activated in concert with loss of MCL-1 expression and its release from the complex. Our data suggest that BAK is the mediator of paclitaxel-induced apoptosis and could be an alternative target for overcoming paclitaxel resistance. PMID:23577147

Miller, Anna V; Hicks, Mark A; Nakajima, Wataru; Richardson, Amanda C; Windle, Jolene J; Harada, Hisashi

2013-04-05

359

Double-coated poly (butylcynanoacrylate) nanoparticulate delivery systems for brain targeting of dalargin via oral administration.  

PubMed

The aim of this study is to evaluate oral administration of poly (butylcyanoacrylate) nanoparticulate delivery systems (PBCA-NDSs), double-coated with Tween 80 and poly (ethylene) glycol (PEG) 20000 for brain delivery of hexapeptide dalargin, an anti-nociceptive peptide that does not cross blood-brain barrier (BBB) by itself. Studies have proven the brain uptake of Tween 80 overcoated nanoparticles after intravenous administration, but studies for brain delivery of nanoparticles after oral administration had been limited due to reduced bioavailability of nanoparticles and extensive degradation of the peptide and/or nanoparticles by gastrointestinal enzymes. To address this problem, dalargin-loaded PBCA-NDS were successively double-coated with Tween 80 and PEG 20000 in varied concentrations of up to 2% each. Measurement of in vivo central anti-nociceptive effect of dalargin along with a dose response curve was obtained by the tail flick test following the oral administration of PBCA-NDSs to mice. Results from the tail flick test indicated that significant dalargin-induced analgesia was observed from PBCA-NDSs with double-coating of Tween and PEG in comparison with single-coating of either Tween or PEG. Hence, it could be concluded that surface coated PBCA-NDS can be used successfully for brain targeting of dalargin or other peptides administered orally. However, further studies are required to elucidate the exact transport mechanism of PBCA-NDSs from gastrointestinal tract to brain. PMID:15858853

Das, Debanjan; Lin, Senshang

2005-06-01

360

Targeted Delivery of GDNF through the Blood-Brain Barrier by MRI-Guided Focused Ultrasound  

PubMed Central

Neurotrophic factors, such as glial cell line-derived neurotrophic factor (GDNF), are promising therapeutic agents for neurodegenerative diseases. However, the application of GDNF to treat these diseases effectively is limited because the blood–brain barrier (BBB) prevents the local delivery of macromolecular therapeutic agents from entering the central nervous system (CNS). Focused ultrasound combined with microbubbles (MBs) using appropriate parameters has been previously demonstrated to be able to open the BBB locally and noninvasively. This study investigated the targeted delivery of GDNF MBs through the BBB by magnetic resonance imaging (MRI)-guided focused ultrasound. Evans Blue extravasation and histological examination were used to determine the optimum focused ultrasound parameters. Enzyme-linked immunosorbent assay was performed to verify the effects of GDNF bound on MBs using a biotin–avidin bridging chemistry method to promote GDNF delivery into the brain. The results showed that GDNF can be delivered locally and noninvasively into the CNS through the BBB using MRI-guided focused ultrasound combined with MBs under optimum parameters. MBs that bind GDNF combined with MRI-guided focused ultrasound may be an effective way of delivering neurotrophic factors directly into the CNS. The method described herein provides a potential means of treating patients with CNS diseases.

Lu, Lin; Liu, Li; Cai, Youli; Zheng, Hairong; Liu, Xin; Yan, Fei; Zou, Chao; Sun, Chengyu; Shi, Jie; Lu, Shukun; Chen, Yun

2012-01-01

361

Ultrasound Targeted Microbubble Destruction Stimulates Cellular Endocytosis in Facilitation of Adeno-Associated Virus Delivery  

PubMed Central

The generally accepted mechanism for ultrasound targeted microbubble destruction (UTMD) to enhance drug and gene delivery is through sonoporation. However, passive uptake of adeno-associated virus (AAV) into cells following sonoporation does not adequately explain observations of enhanced transduction by UTMD. This study investigated alternative mechanisms of UTMD enhancement in AAV delivery. UTMD significantly enhanced transduction efficiency of AAV in a dose-dependent manner. UTMD stimulated a persistent uptake of AAV into the cytoplasm and nucleus. This phenomenon occurred over several hours, suggesting that some viral particles are endocytosed by cells rather than exclusively passing through pores created by sonoporation. Additionally, UTMD enhanced clathrin expression and accumulation at the plasma membrane suggesting greater clathrin-mediated endocytosis following UTMD. Transmission electron microscopy (TEM) revealed that UTMD stimulated formation of clathrin-coated pits (CPs) and uncoated pits (nCPs). Furthermore, inhibition of clathrin-mediated endocytosis partially blocked the enhancement of AAV uptake following UTMD. The results of this study implicate endocytosis as a mechanism that contributes to UTMD-enhanced AAV delivery.

Jin, Li-Fang; Li, Fan; Wang, Hui-Ping; Wei, Fang; Qin, Peng; Du, Lian-Fang

2013-01-01

362

Targeted drug delivery to the peripheral nervous system using gene therapy.  

PubMed

Gene transfer to target delivery of neurotrophic factors to the primary sensory afferent for treatment of polyneuropathy, or of inhibitory neurotransmitters for relief of chronic pain, offers the possibility of a highly selective targeted release of bioactive molecules within the nervous system. Preclinical studies with non-replicating herpes simplex virus (HSV)-based vectors injected into the skin to transduce neurons in the dorsal root ganglion have demonstrated efficacy in reducing-pain related behaviors in animal models of inflammatory pain, neuropathic pain, and pain caused by cancer, and in preventing progression of sensory neuropathy caused by toxins, chemotherapeutic drugs or resulting from diabetes. Successful completion of the first phase 1 clinical trial of HSV-mediated gene transfer in patients with intractable pain from cancer has set the stage for further clinical trials of this approach. PMID:22565023

Wolfe, Darren; Mata, Marina; Fink, David J

2012-04-27

363

A combinatorial approach for targeted delivery using small molecules and reversible masking to bypass nonspecific uptake in vivo.  

PubMed

We have developed a multi-disciplinary approach combining molecular biology, delivery technology, combinatorial chemistry and reversible masking to create improved systemic, targeted delivery of plasmid DNA while avoiding nonspecific uptake in vivo. We initially used a well-characterized model targeting the asialolglycoprotein receptor in the liver. Using our bilamellar invaginated vesicle (BIV) liposomal delivery system with reversible masking, we increased expression in the liver by 76-fold, nearly equaling expression in first-pass organs using non-targeted complexes, with no expression in other organs. The same technology was then applied to efficiently target delivery to a human tumor microenvironment model. We achieved efficient, targeted delivery by attachment of specific targeting ligands to the surface of our BIV complexes in conjunction with reversible masking to bypass nonspecific tissues and organs. We identified ligands that target a human tumor microenvironment created in vitro by co-culturing primary human endothelial cells with human lung or pancreatic cancer cells. The model was confirmed by increased expression of tumor endothelial phenotypes including CD31 and vascular endothelial growth factor-A, and prolonged survival of endothelial capillary-like structures. The co-cultures were used for high-throughput screening of a specialized small molecule library to identify ligands specific for human tumor-associated endothelial cells in vitro. We identified small molecules that enhanced the transfection efficiency of tumor-associated endothelial cells, but not normal human endothelial cells or cancer cells. Intravenous (i.v.) injection of our targeted, reversibly masked complexes into mice, bearing human pancreatic tumor and endothelial cells, specifically increased transfection to this tumor microenvironment approximately 200-fold. Efficacy studies using our optimized targeted delivery of a plasmid encoding thrombospondin-1 eliminated tumors completely after five i.v. injections administered once every week. PMID:20463761

Shi, Q; Nguyen, A T; Angell, Y; Deng, D; Na, C-R; Burgess, K; Roberts, D D; Brunicardi, F C; Templeton, N S

2010-05-13

364

Mammaglobin as a potential molecular target for breast cancer drug delivery  

PubMed Central

Background Mammaglobin (MAM) has been used as a specific molecular marker for breast cancer diagnosis. Recently, several groups of researchers proposed a number of therapeutic strategies targeting this molecule. Some of the strategies are based upon an essential but not demonstrated hypothesis – mammaglobin is associated with the surface of breast cancer cells, which strongly disputes the therapeutic strategies. Results We conducted a computer-based predictive analysis and identified a small fragment at the N-end of MAM as a potential transmembrane domain. We provided several evidences to demonstrate the presence of the membrane-associated MAM. We isolated the membrane protein components from known MAM positive breast cancer cells (MDA-MB361 and MDA-MB415). We showed that about 22–64% of MAM proteins, depending upon the types of the cancer cells, directly attached on the membrane of breast cancer cells, by Western blotting assays. To directly visualize the presence of the membrane-bound MAM protein, we incubated the MAM positive cancer cells with FITC labeled anti-MAM antibody, and observed clear fluorescent signals on the surface of the cells. In studying the MAM protein distribution in human breast cancer tissues, we first identified two immunostain patterns that are associated with the membrane-bound MAM: the membrane stain pattern and luminary surface stain pattern. To test whether the membrane-associated MAM can serve as a molecular target for drug delivery, we conjugated anti-MAM antibody to human low-density lipoprotein (LDL) and loaded doxorubicin (Dox) in the core of LDL. Specific binding and cytotoxicity of the MAM targeted and Dox loaded LDL was tested in the MAM positive breast cancer cells in vitro. Conclusion We first showed that some of MAM protein directly associated with the surface of breast cancer cells. The membrane-associated MAM protein may be utilized as a useful molecular marker for breast cancer targeted drug delivery.

Zuo, Lian; Li, Ly; Wang, Qian; Fleming, Timothy P; You, Shaojin

2009-01-01

365

Intranasal delivery of human beta-amyloid peptide in rats: effective brain targeting.  

PubMed

(1) Intranasal administration is a non-invasive and effective way for the delivery of drugs to brain that circumvents the blood-brain barrier. The aims of the study were to test a nasal delivery system for human beta-amyloid (A beta) peptides, to measure the delivery of the peptides to brain regions, and to test their biological activity in rats. (2) A beta(1-42), in the form of a mixture of oligomers, protofibrils, and fibrils was dissolved in a nasal formulation containing hydrophobic, hydrophylic, and mucoadhesive components. The peptide solution was administered intranasally to rats as a single dose or in repeated doses. (3) Nasally injected A beta labeled with the blue fluorescent dye amino-methyl coumarinyl acetic acid (AMCA) could be detected by fluorescent microscopy in the olfactory bulb and frontal cortex. The concentration of the peptide was quantified by fluorescent spectroscopy, and a significant amount of AMCA-A beta peptide could be detected in the olfactory bulb. Unlabeled A beta also reached the olfactory bulb and frontal cortex of rats as evidenced by intense immunostaining. (4) In behavioral experiments, nasal A beta treatment did not affect anxiety levels (open-field test) and short-term memory (Y-maze test), but significantly impaired long-term spatial memory in the Morris water maze. The treatments did not result in A beta immunization. (5) The tested intranasal delivery system could successfully target a bioactive peptide into the central nervous system and provides a basis for developing a non-invasive and cost effective, new model to study amyloid-induced dysfunctions in the brain. PMID:19806448

Sipos, Eszter; Kurunczi, Anita; Fehér, András; Penke, Zsuzsa; Fülöp, Lívia; Kasza, Agnes; Horváth, János; Horvát, Sándor; Veszelka, Szilvia; Balogh, Gábor; Kürti, Levente; Eros, István; Szabó-Révész, Piroska; Párducz, Arpád; Penke, Botond; Deli, Mária A

2009-10-06

366

Delivery of molecularly targeted therapy to malignant glioma, a disease of the whole brain.  

PubMed

Glioblastoma multiforme, because of its invasive nature, can be considered a disease of the entire brain. Despite recent advances in surgery, radiotherapy and chemotherapy, current treatment regimens have only a marginal impact on patient survival. A crucial challenge is to deliver drugs effectively to invasive glioma cells residing in a sanctuary within the central nervous system. The blood-brain barrier (BBB) restricts the delivery of many small and large molecules into the brain. Drug delivery to the brain is further restricted by active efflux transporters present at the BBB. Current clinical assessment of drug delivery and hence efficacy is based on the measured drug levels in the bulk tumour mass that is usually removed by surgery. Mounting evidence suggests that the inevitable relapse and lethality of glioblastoma multiforme is due to a failure to effectively treat invasive glioma cells. These invasive cells hide in areas of the brain that are shielded by an intact BBB, where they continue to grow and give rise to the recurrent tumour. Effective delivery of chemotherapeutics to the invasive glioma cells is therefore critical, and long-term efficacy will depend on the ability of a molecularly targeted agent to penetrate an intact and functional BBB throughout the entire brain. This review highlights the various aspects of the BBB, and also the brain-tumour-cell barrier (a barrier due to expression of efflux transporters in tumour cells), that together can significantly influence drug response. It then discusses the challenge of glioma as a disease of the whole brain, which lends emphasis to the need to deliver drugs effectively across the BBB to reach both the central tumour and the invasive glioma cells. PMID:21676290

Agarwal, Sagar; Sane, Ramola; Oberoi, Rajneet; Ohlfest, John R; Elmquist, William F

2011-05-13

367

Water-soluble polymers for targeted drug delivery to human squamous carcinoma of head and neck.  

PubMed

Human squamous cell carcinoma of the head and neck (SCCHN) is characterized by over expression of a tumor cell surface-specific receptor namely Hsp47/CBP2 that makes it a favorable candidate for targeted delivery of anticancer drugs. Several synthetic peptides have been identified as effective ligands for binding to CBP2. The purpose of this study is to investigate the potential of water-soluble N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-doxorubicin (Dox) conjugates containing a Hsp47/CBP2 binding peptide sequence, namely WHYPWFQNWAMA for targeted delivery to SCCHN. An HPMA copolymer containing Dox and CBP2 targeting peptide conjugated via lysosomally degradable glycylphenylalanylleucylglycine (GFLG) spacer was synthesized by free radical precipitation copolymerization. A control polymer without targeting moiety was also synthesized. The conjugates were characterized for drug content, peptide content, molecular weight and molecular weight distribution. The uptake of polymeric conjugates by both drug resistant and drug sensitive SCCHN cells were determined in vitro by flow cytometry using FACS scan analysis. Cytotoxicity of the conjugates towards drug sensitive as well as multidrug resistant SCCHN cells were evaluated by a clonal survival assay and compared to free Dox. The cytotoxicity of the free peptide was similarly evaluated. The internalization and subcellular fate of the conjugates in drug sensitive SCCHN cells was monitored using confocal microscopy. The new targetable copolymer contained 0.16 mmole peptide/g polymer. Studies on drug sensitive SCCHN cells demonstrated lesser uptake of both targeted and non-targeted conjugates compared to free Dox suggesting a slower endocytic mechanism of uptake for the conjugates as opposed to rapid diffusion of free Dox. At higher Dox equivalent concentrations (>20 microM) the targeted conjugate showed significantly higher uptake (p < or = 0.028) than the non-targeted conjugate. The uptake of the targeted conjugate was inhibited in the presence of an anti Hsp47 antibody suggesting the involvement of active receptor mediated endocytosis in cell entry of the conjugate. Compared to free Dox, the targeted and non-targeted conjugates caused marginally lower inhibition (p < or = 0.01) of the drug sensitive SCCHN cells. In contrast, the same conjugates showed significantly higher uptake (p < or = 0.004) by drug resistant SCCHN cells and caused significantly higher inhibition (p < or = 0.02) of drug resistant SCCHN cells when compared to free Dox. Results suggest that the polymeric conjugates were able to overcome drug resistance. Confocal microscopy studies demonstrated the uptake of the polymeric conjugates, followed by internalization, intralysosomal localization and subsequent release of Dox. HPMA copolymer-Dox-peptide conjugates targeted to SCCHN cells were able to overcome drug resistance and increase efficacy in vitro. The results suggest that targetable polymeric conjugates have potential to improve systemic head and neck cancer chemotherapy by increasing tumor localization and reducing dose-limiting toxicity. PMID:16036307

Nan, Anjan; Ghandehari, Hamidreza; Hebert, Carla; Siavash, Hessam; Nikitakis, Nikolaos; Reynolds, Mark; Sauk, John J

2005-04-01

368

Benzamide analogue-conjugated polyethylenimine for brain-targeting and gene delivery.  

PubMed

In this study, a small molecule, benzamide analogue, p-hydroxybenzoic acid (p-HA), was used as a novel ligand for brain-targeting gene delivery. p-HA was conjugated to polyethylenimine and further labeled with a near infrared dye, IR820, for in vivo and ex vivo imaging study. Significant fluorescent signal was detected in brain from 0.5 to 24 h after injection compared with unmodified PEI. Then nanoparticles were prepared with p-HA-PEI to encapsulate pEGFP and pGL2 as reporter genes and characterized on the cell level. In 5 y cells green fluorescent protein expression could be observed by fluorescent microscopy and significant higher expression of firefly luciferase was detected in p-HA-PEI/pGL2 group than in PEI/pGL2 group. For in vivo gene expression study, comparable high expression of green fluorescent protein in brain sections was confirmed using both confocal fluorescent microscopy and in vivo fluorescent imaging. All these results suggested that p-HA-PEI could be potentially used for brain targeted gene delivery. PMID:21999822

Li, Jin; Meng, Qinggang; Lei, Yang; Gu, Bing; Liu, Yu; Lu, Weiyue

2011-11-01

369

Targeted delivery of antiprotease to the epithelial surface of human tracheal xenografts.  

PubMed

The cystic fibrosis (CF) lung is uniquely susceptible to Pseudomonas aeruginosa, and infection with this organism incites an intense, compartmentalized inflammatory response that leads to chronic airway obstruction and bronchiectasis. Neutrophils migrate into the airway, and released neutrophil elastase contributes to the progression of the lung disease characteristic of CF. We have developed a strategy that permits the delivery of antiproteases to the inaccessible CF airways by targeting the respiratory epithelium via the human polymeric immunoglobulin receptor (hpIgR). A fusion protein consisting of a single-chain Fv directed against secretory component, the extracellular portion of the pIgR, linked to human alpha1-antitrypsin is effectively ferried across human tracheal xenografts and delivers the antiprotease to the apical surface to a much greater extent than occurs by passive diffusion of human alpha1-antitrypsin alone. Targeted antiprotease delivery paralleled hpIgR expression in the respiratory epithelium in vivo and was not increased by escalating dose, so airway penetration was receptor-dependent, not dose-dependent. Thus, this approach provides us with the ability to deliver therapeutics, like antiproteases, specifically to the lumenal surface of the respiratory epithelium, within the airway surface fluid, where it will be in highest concentration at this site. PMID:12615618

Ferkol, Thomas; Cohn, Leah A; Phillips, Thomas E; Smith, Arnold; Davis, Pamela B

2003-02-25

370

Use of Microsphere Technology for Targeted Delivery of Rifampin to Mycobacterium tuberculosis-Infected Macrophages  

PubMed Central

Microsphere technology was used to develop formulations of rifampin for targeted delivery to host macrophages. These formulations were prepared by using biocompatible polymeric excipients of lactide and glycolide copolymers. Release characteristics were examined in vitro and also in two monocytic cell lines, the murine J774 and the human Mono Mac 6 cell lines. Bioassay assessment of cell culture supernatants from monocyte cell lines showed release of bioactive rifampin during a 7-day experimental period. Treatment of Mycobacterium tuberculosis H37Rv-infected monocyte cell lines with rifampin-loaded microspheres resulted in a significant decrease in numbers of CFU at 7 days following initial infection, even though only 8% of the microsphere-loaded rifampin was released. The levels of rifampin released from microsphere formulations within monocytes were more effective at reducing M. tuberculosis intracellular growth than equivalent doses of rifampin given as a free drug. These results demonstrate that rifampin-loaded microspheres can be formulated for effective sustained and targeted delivery to host macrophages.

Barrow, Esther L. W.; Winchester, Gary A.; Staas, Jay K.; Quenelle, Debra C.; Barrow, William W.

1998-01-01

371

Bolaamphiphilic vesicles encapsulating iron oxide nanoparticles: new vehicles for magnetically targeted drug delivery.  

PubMed

Bolaamphiphiles - amphiphilic molecules consisting of two hydrophilic headgroups linked by a hydrophobic chain - form highly stable vesicles consisting of a monolayer membrane that can be used as vehicles to deliver drugs across biological membranes, particularly the blood-brain barrier (BBB). We prepared new vesicles comprising bolaamphiphiles (bolavesicles) that encapsulate iron oxide nanoparticles (IONPs) and investigated their suitability for targeted drug delivery. Bolavesicles displaying different headgroups were studied, and the effect of IONP encapsulation upon membrane interactions and cell uptake were examined. Experiments revealed more pronounced membrane interactions of the bolavesicles assembled with IONPs. Furthermore, enhanced internalization and stability of the IONP-bolavesicles were observed in b.End3 brain microvessel endothelial cells - an in vitro model of the blood-brain barrier. Our findings indicate that embedded IONPs modulate bolavesicles' physicochemical properties, endow higher vesicle stability, and enhance their membrane permeability and cellular uptake. IONP-bolavesicles thus constitute a promising drug delivery platform, potentially targeted to the desired location using external magnetic field. PMID:23623794

Philosof-Mazor, Liron; Dakwar, George R; Popov, Mary; Kolusheva, Sofiya; Shames, Alexander; Linder, Charles; Greenberg, Sarina; Heldman, Eliahu; Stepensky, David; Jelinek, Raz

2013-04-24

372

Effect of Glycocalyx on Drug Delivery Carriers Targeted to Endothelial Cells  

PubMed Central

Animal models have shown that coupling ligands, targeted to endothelium surface receptors, with drug delivery carriers (DDC) can optimize the treatment of diseases by specific vascular delivery. The endothelium is exposed to hydrodynamic forces that modulate the expression of these cellular adhesion molecules (CAMs) and affect the structural and biological activity of endothelial cells (ECs). In order to investigate how delivery of targeted DDC can be optimized, we investigated carriers binding to flow adapted ECs under flow conditions. Comparison of live ECs to fixed cells from our previous experiments give insight into the effect of receptor motility on the cell surface as well as the effect of other factors such as glycocalyx (a protective layer of carbohydrates on the surface of cells) and actin remodeling. A flow chamber model is used to investigate how DDC size variation alters binding under flow conditions. Binding experiments were done with and without glycocalyx in order to elucidate its protective effect. Using fluorescence microscopy we determined the real time binding and rolling speeds of DDC under flow conditions. We also demonstrate the presence of glycocalyx and image actin filament remodeling. The binding of 1 µm carriers to ECs decreased after flow adaptation, in both non-activated and TNF-? activated ECs compared to non-flow adapted live cells. After removal of the glycocalyx by degrading enzymes binding increased in quiescent ECs, but only increased in activated cells after 2 hr of perfusion with particles. The binding with 100 nm carriers also decreased after flow adaptation but to a lesser extent and partially increased after enzyme degradation. These experiments give insight as to how tunable affinity parameters can be optimized to enhance therapeutic capabilities.

Calderon, Andres J.; Baig, Madiha; Pichette, Ben; Muzykantov, Vladimir; Muro, Silvia; Eckmann, David M.

2010-01-01

373

Self-assembly of morphology-tunable architectures from tetraarylmethane derivatives for targeted drug delivery.  

PubMed

Tetraarylmethane compounds consisting of two pyrogallol and two aniline units, namely, Ar2CAr'2 {Ar = 3,4,5-C6H2(OH)3 and Ar' = 3,5-R2-4-C6H2NH2 [R = Me (1), iPr (2)]} exhibit excellent self-assembly behavior. Compound 1 yields size-tunable hollow nanospheres (HNSs) with a narrow size distribution, and 2 yields various morphologies ranging from microtubules to microrods via self-assembly induced by hydrogen bonding and ?-? stacking interactions. On the basis of the experimental results, a plausible mechanism for morphology tunability was proposed. As a means of utilizing the self-assembled HNSs for targeting controlled drug delivery, folic acid (FA) and rhodamine 6G (Rh6G) were grafted onto compound 1 to yield the FA-Rh6G-1 complex. The HNSs fabricated with FA-Rh6G-1 showed low cytotoxicity against human embryonic kidney 293T cells and CT26 colon carcinoma cells and good doxorubicin (DOX) loading capacity (9.6 wt %). The FA receptor-mediated endocytosis of FA-Rh6G-1 HNSs examined by using a confocal laser scanning microscope and a flow cytometer revealed that the uptake of FA-Rh6G-1 HNSs into CT26 cells was induced by FA receptor-mediated endocytosis. In vitro drug delivery tests showed that the DOX molecules were released from the resulting HNSs in a sustainable and pH-dependent manner, demonstrating a potential application for HNSs in targeted drug delivery for cancer therapy. PMID:23425332

Huang, Xinhua; Jeong, Young-Il; Moon, Byeong Kyu; Zhang, Lidong; Kang, Dae Hwan; Kim, Il

2013-03-01

374

A novel folate-modified self-microemulsifying drug delivery system of curcumin for colon targeting  

PubMed Central

Background The objective of this study was to prepare, characterize, and evaluate a folate-modified self-microemulsifying drug delivery system (FSMEDDS) with the aim to improve the solubility of curcumin and its delivery to the colon, facilitating endocytosis of FSMEDDS mediated by folate receptors on colon cancer cells. Methods Ternary phase diagrams were constructed in order to obtain the most efficient self-emulsification region, and the formulation of curcumin-loaded SMEDDS was optimized by a simplex lattice experiment design. Then, three lipophilic folate derivatives (folate-polyethylene glycol-distearoylphosphatidylethanolamine, folate-polyethylene glycol-cholesteryl hemisuccinate, and folate-polyethylene glycol-cholesterol) used as a surfactant were added to curcumin-loaded SMEDDS formulations. An in situ colon perfusion method in rats was used to optimize the formulation of FSMEDDS. Curcumin-loaded FSMEDDS was then filled into colon-targeted capsules and the in vitro release was investigated. Cytotoxicity studies and cellular uptake studies was used in this research. Results The optimal formulation of FSMEDDS obtained with the established in situ colon perfusion method in rats was comprised of 57.5% Cremophor® EL, 32.5% Transcutol® HP, 10% Capryol™ 90, and a small amount of folate-polyethylene glycol-cholesteryl hemisuccinate (the weight ratio of folate materials to Cremophor EL was 1:100). The in vitro release results indicated that the obtained formulation of curcumin could reach the colon efficiently and release the drug immediately. Cellular uptake studies analyzed with fluorescence microscopy and flow cytometry indicated that the FSMEDDS formulation could efficiently bind with the folate receptors on the surface of positive folate receptors cell lines. In addition, FSMEDDS showed greater cytotoxicity than SMEDDS in the above two cells. Conclusion FSMEDDS-filled colon-targeted capsules are a potential carrier for colon delivery of curcumin.

Zhang, Lin; Zhu, Weiwei; Yang, Chunfen; Guo, Hongxia; Yu, Aihua; Ji, Jianbo; Gao, Yan; Sun, Min; Zhai, Guangxi

2012-01-01

375

Feasibility of targeted drug delivery to selective areas of the retina  

SciTech Connect

A new method was developed to deliver locally a bolus dose of a drug to the retinal vasculature. The targeted delivery system was based on encapsulating the drug in heat-sensitive liposomes, which are injected intravenously and lysed in the retinal vessels by a heat pulse generated by a laser. To test if substances delivered in the vessels could also penetrate into the surrounding tissue, 6-carboxyfluorescein was encapsulated in liposomes and used as a marker for drug penetration. Moderate argon laser pulses were applied to the retinal vessels of Dutch pigmented rabbits to induce breakdown of the blood-retinal barrier (BRB). A suspension of liposomes at a dose of 2 ml/kg body weight, corresponding to a carboxyfluorescein dose of 12 mg/kg, was injected into the ear vein. The dye was released from the liposomes proximal to the damaged portion of the vessel. Fundus fluorescein angiograms were recorded with a video camera and digitized for subsequent image analysis. The penetration of carboxyfluorescein into the retinal tissue was evaluated by comparing the fluorescence intensity of the area around the damaged vessel with that of an adjacent control area. The dye penetration increased with the numbers of laser applications (P less than 0.001). The leakage was localized distally to the released site and was restricted to areas with a disrupted BRB. The mass of carboxyfluorescein that penetrated gradually spread with time. Both veins and arteries could be used for the targeted delivery. These results indicated that this delivery system, which is fully controllable by laser through the pupil, can deliver drugs inside the vasculature and into the retinal tissue wherever the BRB is disrupted.

Ogura, Y.; Guran, T.; Shahidi, M.; Mori, M.T.; Zeimer, R.C. (Department of Ophthalmology, UIC Eye Center, University of Illinois, College of Medicine, Chicago (USA))

1991-07-01

376

Targeting the neonatal Fc receptor for antigen delivery using engineered Fc fragments1  

PubMed Central

The development of approaches for antigen delivery to the appropriate subcellular compartments of APCs and the optimization of antigen persistence are both of central relevance for the induction of protective immunity or tolerance. The expression of the Fc receptor, FcRn, in APCs and its localization to the endosomal system suggest that it might serve as a target for antigen delivery using engineered Fc fragment-epitope fusions. The impact of FcRn binding characteristics of an Fc fragment on in vivo persistence allows this property to also be modulated. We have therefore generated recombinant Fc (mouse IgG1-derived) fusions containing the N-terminal epitope of myelin basic protein that is associated with EAE in H-2u mice. The Fc fragments have distinct binding properties for FcRn that result in differences in intracellular trafficking and in vivo half-lives, allowing the impact of these characteristics on CD4+ T cell responses to be evaluated. To dissect the relative roles of FcRn and the ‘classical’ Fc?Rs in antigen delivery, analogous aglycosylated Fc-MBP fusions have been generated. We show that engineered Fc fragments with increased affinities for FcRn at pH 6.0–7.4 are more effective in delivering antigen to FcRn-expressing APCs in vitro relative to their lower affinity counterparts. However, higher affinity of the FcRn-Fc interaction at near neutral pH results in decreased in vivo persistence. The trade-off between improved FcRn targeting efficiency and lower half-life becomes apparent during analyses of T cell proliferative responses in mice, particularly when Fc-MBP fusions with both FcRn and Fc?R binding activity are used.

Mi, Wentao; Wanjie, Sylvia; Lo, Su-Tang; Gan, Zhuo; Pickl-Herk, Beatrix; Ober, Raimund J.; Ward, E. Sally

2009-01-01

377

Plasmid pORF-hTRAIL and doxorubicin co-delivery targeting to tumor using peptide-conjugated polyamidoamine dendrimer.  

PubMed

A combination cancer therapy was investigated via co-delivery of therapeutic gene encoding human tumor necrosis factor-related apoptosis-inducing ligand (pORF-hTRAIL) and doxorubicin (DOX) using a tumor-targeting carrier, peptide HAIYPRH (T7)-conjugated polyethylene glycol-modified polyamidoamine dendrimer (PAMAM-PEG-T7). T7, a transferrin receptor-specific peptide, was chosen as the ligand to target the co-delivery system to the tumor cells expressing transferrin receptors. The result of fluorescence scanning showed that about 375 DOX molecules were bound to one pORF-hTRAIL molecule. The co-delivery system was constructed based on the electrostatic interactions between pORF-hTRAIL-DOX complex and cationic PAMAM-PEG-T7. T7-modified co-delivery system showed higher efficiency in cellular uptake and gene expression than unmodified co-delivery system in human liver cancer Bel-7402 cells, and accumulated in tumor more efficiently in vivo. In comparison with single DOX or pORF-hTRAIL delivery system, co-delivery system induced apoptosis of tumor cells in vitro and inhibited tumor growth in vivo more efficiently. In mice bearing Bel-7402 xenografts, lower doses of co-delivery system (4 ?g DOX/mouse, about 0.16 mg/kg) effectively inhibited tumor growth comparable to high doses (5 mg/kg) of free doxorubicin (77% versus 69%). These results suggested that T7-mediated co-delivery system of DOX and pORF-hTRAIL was a simply prepared, combined delivery platform which can significantly improve the anti-tumor effect. This co-delivery system might widen the therapeutic window and allow for the selective destruction of cancer cells. PMID:20971503

Han, Liang; Huang, Rongqin; Li, Jianfeng; Liu, Shuhuan; Huang, Shixian; Jiang, Chen

2010-10-23

378

Targeted drug delivery to tumor vasculature by a carbohydrate mimetic peptide.  

PubMed

Although numerous carbohydrates play significant roles in mammalian cells, carbohydrate-based drug discovery has not been explored due to the technical difficulty of chemically synthesizing complex carbohydrate structures. Previously, we identified a series of carbohydrate mimetic peptides and found that a 7-mer peptide, designated I-peptide, inhibits hematogenous carbohydrate-dependent cancer cell colonization. During analysis of the endothelial surface receptor for I-peptide, we found that I-peptide bound to annexin 1 (Anxa1). Because Anxa1 is a highly specific tumor vasculature surface marker, we hypothesized that an I-peptide-like peptide could target anticancer drugs to the tumor vasculature. This study identifies IFLLWQR peptide, designated IF7, as homing to tumors. When synthetic IF7 peptide was conjugated to fluorescent Alexa 488 (A488) and injected intravenously into tumor-bearing mice, IF7-A488 targeted tumors within minutes. IF7 conjugated to the potent anticancer drug SN-38 and injected intravenously into nude mice carrying human colon HCT116 tumors efficiently suppressed tumor growth at low dosages with no apparent side effects. These results suggest that IF7 serves as an efficient drug delivery vehicle by targeting Anxa1 expressed on the surface of tumor vasculature. Given its extremely specific tumor-targeting activity, IF7 may represent a clinically relevant vehicle for anticancer drugs. PMID:22114188

Hatakeyama, Shingo; Sugihara, Kazuhiro; Shibata, Toshiaki K; Nakayama, Jun; Akama, Tomoya O; Tamura, Naoaki; Wong, Shuk-Man; Bobkov, Andrey A; Takano, Yutaka; Ohyama, Chikara; Fukuda, Minoru; Fukuda, Michiko N

2011-11-23

379

The targeted delivery of multicomponent cargos to cancer cells by nanoporous particle-supported lipid bilayers  

NASA Astrophysics Data System (ADS)

Encapsulation of drugs within nanocarriers that selectively target malignant cells promises to mitigate side effects of conventional chemotherapy and to enable delivery of the unique drug combinations needed for personalized medicine. To realize this potential, however, targeted nanocarriers must simultaneously overcome multiple challenges, including specificity, stability and a high capacity for disparate cargos. Here we report porous nanoparticle-supported lipid bilayers (protocells) that synergistically combine properties of liposomes and nanoporous particles. Protocells modified with a targeting peptide that binds to human hepatocellular carcinoma exhibit a 10,000-fold greater affinity for human hepatocellular carcinoma than for hepatocytes, endothelial cells or immune cells. Furthermore, protocells can be loaded with combinations of therapeutic (drugs, small interfering RNA and toxins) and diagnostic (quantum dots) agents and modified to promote endosomal escape and nuclear accumulation of selected cargos. The enormous capacity of the high-surface-area nanoporous core combined with the enhanced targeting efficacy enabled by the fluid supported lipid bilayer enable a single protocell loaded with a drug cocktail to kill a drug-resistant human hepatocellular carcinoma cell, representing a 106-fold improvement over comparable liposomes.

Ashley, Carlee E.; Carnes, Eric C.; Phillips, Genevieve K.; Padilla, David; Durfee, Paul N.; Brown, Page A.; Hanna, Tracey N.; Liu, Juewen; Phillips, Brandy; Carter, Mark B.; Carroll, Nick J.; Jiang, Xingmao; Dunphy, Darren R.; Willman, Cheryl L.; Petsev, Dimiter N.; Evans, Deborah G.; Parikh, Atul N.; Chackerian, Bryce; Wharton, Walker; Peabody, David S.; Brinker, C. Jeffrey

2011-05-01

380

In vivo tumor targeting and image-guided drug delivery with antibody-conjugated, radiolabeled mesoporous silica nanoparticles.  

PubMed

Since the first use of biocompatible mesoporous silica (mSiO2) nanoparticles as drug delivery vehicles, in vivo tumor targeted imaging and enhanced anticancer drug delivery has remained a major challenge. In this work, we describe the development of functionalized mSiO2 nanoparticles for actively targeted positron emission tomography (PET) imaging and drug delivery in 4T1 murine breast tumor-bearing mice. Our structural design involves the synthesis, surface functionalization with thiol groups, PEGylation, TRC105 antibody (specific for CD105/endoglin) conjugation, and (64)Cu-labeling of uniform 80 nm sized mSiO2 nanoparticles. Systematic in vivo tumor targeting studies clearly demonstrated that (64)Cu-NOTA-mSiO2-PEG-TRC105 could accumulate prominently at the 4T1 tumor site via both the enhanced permeability and retention effect and TRC105-mediated binding to tumor vasculature CD105. As a proof-of-concept, we also demonstrated successful enhanced tumor targeted delivery of doxorubicin (DOX) in 4T1 tumor-bearing mice after intravenous injection of DOX-loaded NOTA-mSiO2-PEG-TRC105, which holds great potential for future image-guided drug delivery and targeted cancer therapy. PMID:24083623

Chen, Feng; Hong, Hao; Zhang, Yin; Valdovinos, Hector F; Shi, Sixiang; Kwon, Glen S; Theuer, Charles P; Barnhart, Todd E; Cai, Weibo

2013-10-01

381

Targeted delivery of chlorotoxin-modified DNA-loaded nanoparticles to glioma via intravenous administration.  

PubMed

Gene therapy offers great potential for brain glioma. However, therapeutic genes could not reach glioma spontaneously. A glioma-targeting gene delivery system is highly desired to transfer exogenous genes throughout the tumor focus. In this study, the nanoscopic high-branching dendrimer, polyamidoamine (PAMAM), was selected as the main vector. Chlorotoxin (CTX), which has been demonstrated to bind specifically to receptor expressed in glioma, was exploited as the targeting ligand to conjugate PAMAM via bifunctional polyethyleneglycol (PEG), yielding PAMAM-PEG-CTX. The cellular uptake of CTX itself was observed apparently in C6 glioma cells, almost not in 293 cells. The modification of CTX could significantly increase the cellular uptake of vectors and the DNA-loaded nanoparticles (NPs) in C6 cells. The in vivo distribution of PAMAM-PEG-CTX/DNA NPs in the brain was higher than that of PAMAM/DNA NPs and PAMAM-PEG/DNA NPs. Furthermore, the gene expression of PAMAM-PEG-CTX/DNA NPs was higher and broader in glioma than that of unmodified and PEG-modified counterparts. The TUNEL analysis showed a more wide-extended apoptosis in the CTX-modified group, compared to other groups including commercial temozolomide group. The median survival time of CTX-modified group and temozolomide group was 59.5 and 49 days, respectively, significantly longer than that of other groups. The results suggested that CTX could be exploited as a special glioma-targeting ligand, and PAMAM-PEG-CTX/DNA NPs is a potential non-viral delivery system for gene therapy of glioma via intravenous administration. PMID:21185076

Huang, Rongqin; Ke, Weilun; Han, Liang; Li, Jianfeng; Liu, Shuhuan; Jiang, Chen

2010-12-24

382

An in vitro assay to measure targeted drug delivery to bone mineral.  

PubMed

Targeted delivery of drugs to their site of action is a promising strategy to decrease adverse effects and enhance efficacy, but successful applications of this strategy have been scarce. Human bone is a tissue with unique properties due to its high hydroxyapatite mineral content. However, with the exception of bisphosphonates, bone mineral has not been targeted in a successful clinical application of drugs that act on bone, such as anti-resorptive or bone anabolic agents. Herein we present an NMR-based in vitro assay to measure binding affinities of small molecules to hydroxyapatite (HAP) or bone powder. Binding was shown to be specific and competitive, and the assay can be carried out in a direct binding format or in competition mode. A selection of clinically relevant bisphosphonates was ranked by their binding affinity for HAP. The binding affinity decreases in the order: pamidronate > alendronate > zoledronate > risedronate > ibandronate. The differences in binding affinities span a factor of 2.1 between pamidronate and ibandronate, consistent with previous studies. The rank order is very similar with bone powder, although the binding capacity of bone powder is smaller and binding kinetics are slower. A zoledronate derivative that lacks the central hydroxy group bi