Transferrin-Bearing, Zein-Based Hybrid Lipid Nanoparticles for Drug and Gene Delivery to Prostate Cancer Cells.

Gene therapy holds great promise for treating prostate cancer unresponsive to conventional therapies. However, the lack of delivery systems that can transport therapeutic DNA and drugs while targeting tumors without harming healthy tissues presents a significant challenge. This study aimed to explore the potential of novel hybrid lipid nanoparticles, composed of biocompatible zein and conjugated to the cancer-targeting ligand transferrin. These nanoparticles were designed to entrap the anti-cancer drug docetaxel and carry plasmid DNA, with the objective of improving the delivery of therapeutic payloads to prostate cancer cells, thereby enhancing their anti-proliferative efficacy and gene expression levels. These transferrin-bearing, zein-based hybrid lipid nanoparticles efficiently entrapped docetaxel, leading to increased uptake by PC-3 and LNCaP cancer cells and significantly enhancing anti-proliferative efficacy at docetaxel concentrations exceeding 1 µg/mL. Furthermore, they demonstrated proficient DNA condensation, exceeding 80% at polymer-DNA weight ratios of 1500:1 and 2000:1. This resulted in increased gene expression across all tested cell lines, with the highest transfection levels up to 11-fold higher than those observed with controls, in LNCaP cells. These novel transferrin-bearing, zein-based hybrid lipid nanoparticles therefore exhibit promising potential as drug and gene delivery systems for prostate cancer therapy.

Preparation of Zein-Based Nanoparticles: Nanoprecipitation versus Microfluidic-Assisted Manufacture, Effects of PEGylation on Nanoparticle Characteristics and Cellular Uptake by Melanoma Cells.

Background: The manufacture of nanoparticles using manual methods is hampered by its challenging scale-up and poor reproducibility. To overcome this issue, the production of zein nanoparticles entrapping a lipophilic drug model, coumarin-6, by using a microfluidic system was assessed in this study. The influence of PEG density and chain length on zein nanoparticle characteristics, as well as their uptake efficacy in melanoma cancer cells, was also evaluated. Methods: Zein nanoparticles were prepared by both manual and microfluidic approaches to allow comparison between the two processes. PEGylated zein nanoparticles with various PEG densities and chain lengths were produced by nanoprecipitation and characterized. Their cellular uptake was evaluated on B16F10 melanoma cancer cells in vitro. Results: Zein nanoparticles have successfully been produced by both manual and microfluidic approaches. Parameters such as total flow rate and flow rate ratio of the aqueous and organic phases in microfluidic process, as well as the method preparation and aqueous to organic phase volume ratio during nanoprecipitation, have been shown to strongly influence the characteristics of the resulting nanoparticles. Continuous microfluidics led to the production of nanoparticles with low yield and drug entrapment, unlike nanoprecipitation, which resulted in zein nanoparticles with an appropriate size and an optimal drug entrapment efficiency of 64%. The surface modification of the nanoparticles produced by nanoprecipitation, with lower PEG density and shorter PEG chain length made mPEG5K-zein (0.5:1) the most favorable formulation in our study, resulting in enhanced stability and higher coumarin-6 uptake by melanoma cancer cells. Conclusion: mPEG5K-zein (0.5:1) nanoparticles prepared by nanoprecipitation were the most promising formulation in our study, exhibiting increased stability and enhancing coumarin-6 uptake by melanoma cancer cells.

Lactoferrin- and Dendrimer-Bearing Gold Nanocages for Stimulus-Free DNA Delivery to Prostate Cancer Cells.

Background: The use of gene therapy to treat prostate cancer is hampered by the lack of effective nanocarriers that can selectively deliver therapeutic genes to cancer cells. To overcome this, we hypothesize that conjugating lactoferrin, a tumor-targeting ligand, and the diaminobutyric polypropylenimine dendrimer into gold nanocages, followed by complexation with a plasmid DNA, would enhance gene expression and anti-proliferation activity in prostate cancer cells without the use of external stimuli. Methods: Novel gold nanocages bearing lactoferrin and conjugated to diaminobutyric polypropylenimine dendrimer (AuNCs-DAB-Lf) were synthesized and characterized. Following complexation with a plasmid DNA, their gene expression, cellular uptake and anti-proliferative efficacies were evaluated on PC-3 prostate cancer cells. Results: AuNCs-DAB-Lf was able to complex DNA at conjugate: DNA weight ratios 5:1 onwards. Gene expression was at its highest after treatment with AuNCs-DAB-Lf at a weight ratio of 10:1, as a result of a significant increase in DNA uptake mediated by the conjugate at that ratio in PC-3 cells. Consequently, the anti-proliferative activity of AuNCs-DAB-Lf-DNA encoding TNFα was significantly improved by up to 9-fold compared with DAB dendriplex encoding TNFα. Conclusion: Lactoferrin-bearing dendrimer-conjugated gold nanocages are highly promising gene delivery systems for the treatment of prostate cancer.

Limited Impact of the Protein Corona on the Cellular Uptake of PEGylated Zein Micelles by Melanoma Cancer Cells.

The formation of a protein layer "corona" on the nanoparticle surface upon entry into a biological environment was shown to strongly influence the interactions with cells, especially affecting the uptake of nanomedicines. In this work, we present the impact of the protein corona on the uptake of PEGylated zein micelles by cancer cells, macrophages, and dendritic cells. Zein was successfully conjugated with poly(ethylene glycol) (PEG) of varying chain lengths (5K and 10K) and assembled into micelles. Our results demonstrate that PEGylation conferred stealth effects to the zein micelles. The presence of human plasma did not impact the uptake levels of the micelles by melanoma cancer cells, regardless of the PEG chain length used. In contrast, it decreased the uptake by macrophages and dendritic cells. These results therefore make PEGylated zein micelles promising as potential drug delivery systems for cancer therapy.

Lactoferrin-Bearing Gold Nanocages for Gene Delivery in Prostate Cancer Cells in vitro.

BACKGROUND: Gold nanocages have been widely used as multifunctional platforms for drug and gene delivery, as well as photothermal agents for cancer therapy. However, their potential as gene delivery systems for cancer treatment has been reported in combination with chemotherapeutics and photothermal therapy, but not in isolation so far. The purpose of this work was to investigate whether the conjugation of gold nanocages with the cancer targeting ligand lactoferrin, polyethylene glycol and polyethylenimine could lead to enhanced transfection efficiency on prostate cancer cells in vitro, without assistance of external stimulation. METHODS: Novel lactoferrin-bearing gold nanocages conjugated to polyethylenimine and polyethylene glycol have been synthesized and characterized. Their transfection efficacy and cytotoxicity were assessed on PC-3 prostate cancer cell line following complexation with a plasmid DNA. RESULTS: Lactoferrin-bearing gold nanocages, alone or conjugated with polyethylenimine and polyethylene glycol, were able to condense DNA at conjugate:DNA weight ratios 5:1 and higher. Among all gold conjugates, the highest gene expression was obtained following treatment with gold complex conjugated with polyethylenimine and lactoferrin, at weight ratio 40:1, which was 1.71-fold higher than with polyethylenimine. This might be due to the increased DNA cellular uptake observed with this conjugate, by up to 8.65-fold in comparison with naked DNA. CONCLUSION: Lactoferrin-bearing gold nanocages conjugates are highly promising gene delivery systems to prostate cancer cells.

Regression of Melanoma Following Intravenous Injection of Plumbagin Entrapped in Transferrin-Conjugated, Lipid-Polymer Hybrid Nanoparticles.

BACKGROUND: Plumbagin, a naphthoquinone extracted from the officinal leadwort presenting promising anti-cancer properties, has its therapeutic potential limited by its inability to reach tumors in a specific way at a therapeutic concentration following systemic injection. The purpose of this study is to assess whether a novel tumor-targeted, lipid-polymer hybrid nanoparticle formulation of plumbagin would suppress the growth of B16-F10 melanoma in vitro and in vivo. METHODS: Novel lipid-polymer hybrid nanoparticles entrapping plumbagin and conjugated with transferrin, whose receptors are present in abundance on many cancer cells, have been developed. Their cellular uptake, anti-proliferative and apoptosis efficacy were assessed on various cancer cell lines in vitro. Their therapeutic efficacy was evaluated in vivo after tail vein injection to mice bearing B16-F10 melanoma tumors. RESULTS: The transferrin-bearing lipid-polymer hybrid nanoparticles loaded with plumbagin resulted in the disappearance of 40% of B16-F10 tumors and regression of 10% of the tumors following intravenous administration. They were well tolerated by the mice. CONCLUSION: These therapeutic effects, therefore, make transferrin-bearing lipid-polymer hybrid nanoparticles entrapping plumbagin a highly promising anti-cancer nanomedicine.

Octadecyl chain-bearing PEGylated poly(propyleneimine)-based dendrimersomes: physicochemical studies, redox-responsiveness, DNA condensation, cytotoxicity and gene delivery to cancer cells.

Stimuli-responsive nanocarriers have become increasingly important for nucleic acid and drug delivery in cancer therapy. Here, we report the synthesis, characterization and evaluation of disulphide-linked, octadecyl (C18 alkyl) chain-bearing PEGylated generation 3-diaminobutyric polypropylenimine dendrimer-based vesicles (or dendrimersomes) for gene delivery. The lipid-bearing PEGylated dendrimer was successfully synthesized through in situ two-step reaction. It was able to spontaneously self-assemble into stable, cationic, nanosized vesicles, with low critical aggregation concentration value, and also showed redox-responsiveness in presence of a glutathione concentration similar to that of the cytosolic reducing environment. In addition, it was able to condense more than 70% of DNA at dendrimer: DNA weight ratios of 5 : 1 and higher. This dendriplex resulted in an enhanced cellular uptake of DNA at dendrimer: DNA weight ratios of 10 : 1 and 20 : 1, by up to 16-fold and by up to 28-fold compared with naked DNA in PC-3 and DU145 prostate cancer cell lines respectively. At a dendrimer: DNA weight ratio of 20 : 1, it led to an increase in gene expression in PC-3 and DU145 cells, compared with DAB dendriplex. These octadecyl chain-bearing, PEGylated dendrimer-based vesicles are therefore promising redox-sensitive drug and gene delivery systems for potential applications in combination cancer therapy.

Anti-Tumor Activity of Intravenously Administered Plumbagin Entrapped in Targeted Nanoparticles.

Plumbagin, a natural naphthoquinone from the officinal leadwort, has recently been shown to exert promising anti-cancer effects. However, its therapeutic use is hampered by its failure to specifically reach tumors after intravenous administration, without secondary effects on normal tissues. Its poor solubility in water and rapid elimination following in vivo administration further limit its potential use. We hypothesize that the entrapment of plumbagin within PEGylated PLGA nanoparticles conjugated with transferrin, whose receptors are overexpressed on many types of cancer cells, could lead to a selective delivery of the drug to tumors following intravenous administration and enhance its chemotherapeutic effects. The objectives of this study were therefore to prepare and characterize transferrin-conjugated, PEGylated PLGA nanoparticles entrapping plumbagin, and to assess their anti-cancer efficacy in vitro as well as in tumor-bearing mice. The intravenous administration of transferrin-conjugated PEGylated PLGA nanoparticles resulted in the complete suppression of 10% of B16-F10 tumors and regression of 30% of the tumors, with improvement of the animal survival compared to controls. The treatment was well tolerated by the animals. Transferrin-bearing PEGylated PLGA nanoparticles entrapping plumbagin are therefore highly promising therapeutic systems, able to lead to tumor regression and even suppression after intravenous administration without visible toxicity.

Development of transferrin-bearing vesicles encapsulating aspirin for cancer therapy.

Originally developed for the treatment of inflammatory disorders, the non-steroidal anti-inflammatory drug aspirin was shown to have a preventive effect against cancer in the past decades. Most importantly, recent studies suggested that it might also provide a therapeutic benefit in the treatment of cancer in vitro. However, this drug failed to specifically reach tumors at a therapeutic concentration following intravenous administration, thus resulting in lack of efficacy on tumors. In this work, we demonstrated that aspirin could be formulated in transferrin-bearing vesicles and that this tumor-targeted formulation could lead to an increase in the anti-proliferative efficacy of the drug in three cancer cell lines in vitro. The in vitro therapeutic efficacy of aspirin was significantly improved when formulated in transferrin-bearing vesicles, by about 2-fold compared to that of drug solution. These results are promising and support the optimization of this delivery system to further improve its potential as a therapeutic tool in combination with other anti-cancer therapies.

Repurposing screen identifies mebendazole as a clinical candidate to synergise with docetaxel for prostate cancer treatment.

BACKGROUND: Docetaxel chemotherapy in prostate cancer has a modest impact on survival. To date, efforts to develop combination therapies have not translated into new treatments. We sought to develop a novel therapeutic strategy to tackle chemoresistant prostate cancer by enhancing the efficacy of docetaxel. METHODS: We performed a drug-repurposing screen by using murine-derived prostate cancer cell lines driven by clinically relevant genotypes. Cells were treated with docetaxel alone, or in combination with drugs (n = 857) from repurposing libraries, with cytotoxicity quantified using High Content Imaging Analysis. RESULTS: Mebendazole (an anthelmintic drug that inhibits microtubule assembly) was selected as the lead drug and shown to potently synergise docetaxel-mediated cell killing in vitro and in vivo. Dual targeting of the microtubule structure was associated with increased G2/M mitotic block and enhanced cell death. Strikingly, following combined docetaxel and mebendazole treatment, no cells divided correctly, forming multipolar spindles that resulted in aneuploid daughter cells. Liposomes entrapping docetaxel and mebendazole suppressed in vivo prostate tumour growth and extended progression-free survival. CONCLUSIONS: Docetaxel and mebendazole target distinct aspects of the microtubule dynamics, leading to increased apoptosis and reduced tumour growth. Our data support a new concept of combined mebendazole/docetaxel treatment that warrants further clinical evaluation.

Camptothecin-based dendrimersomes for gene delivery and redox-responsive drug delivery to cancer cells.

Combination therapy involving chemotherapeutic drugs and genes is emerging as a promising strategy to provide a synergistic therapeutic effect, to overcome drug resistance while reducing the severe side effects associated with conventional chemotherapeutic drugs. However, the lack of nanomedicines able to simultaneously carry anti-cancer drugs and nucleic acids limits the application of this therapeutic strategy. To overcome this issue, we proposed to synthesize a pro-drug dendrimer by conjugating the PEGylated, positively charged generation 3-diaminobutyric polypropylenimine dendrimer to the anti-cancer drug camptothecin with a redox-sensitive disulphide linkage, and evaluate its efficacy to co-deliver the complexed DNA and camptothecin to cancer cells. This PEGylated pro-drug dendrimer was found to spontaneously self-assemble into cationic (∼3-5 mV) vesicles at pH 7.4, at a critical aggregation concentration of about 200 µg mL-1. These vesicles (dendrimersomes) became smaller (150-200 nm) with increasing dendrimer concentration and remained stable over 7 days. They were able to release about 70% of the conjugated camptothecin in presence of 50 mM glutathione (equivalent to the intracellular environment of tumor tissue). They could also condense more than 85% of the DNA at dendrimer : DNA weight ratios of 5 : 1 and higher. DNA condensation occurred instantly and was found to be stable for at least 24 h. This led to an enhanced cellular uptake of DNA (by up to 1.6-fold) and increased gene transfection (by up to 2.4-fold) in prostate cancer cells in comparison with the unmodified dendrimer. These novel dendrimersomes are therefore promising for single carrier-based combination cancer therapy.

Transferrin-bearing liposomes entrapping plumbagin for targeted cancer therapy.

The therapeutic potential of plumbagin, a naphthoquinone extracted from the officinal leadwort with anticancer properties, is hampered by its failure to specifically reach tumours at a therapeutic concentration after intravenous administration, without secondary effects on normal tissues. Its use in clinic is further limited by its poor aqueous solubility, its spontaneous sublimation, and its rapid elimination in vivo. We hypothesize that the entrapment of plumbagin within liposomes grafted with transferrin, whose receptors are overexpressed on many cancer cells, could result in a selective delivery to tumours after intravenous administration. The objectives of this study were therefore to prepare and characterize transferrin-targeted liposomes entrapping plumbagin and to evaluate their therapeutic efficacy in vitro and in vivo. The entrapment of plumbagin in transferrin-bearing liposomes led to an increase in plumbagin uptake by cancer cells and improved antiproliferative efficacy and apoptosis activity in B16-F10, A431, and T98G cell lines compared with that observed with the drug solution. In vivo, the intravenous injection of transferrin-bearing liposomes entrapping plumbagin led to tumour suppression for 10% of B16-F10 tumours and tumour regression for a further 10% of the tumours. By contrast, all the tumours treated with plumbagin solution or left untreated were progressive. The animals did not show any signs of toxicity. Transferrin-bearing liposomes entrapping plumbagin are therefore highly promising therapeutic systems that should be further optimized as a therapeutic tool for cancer treatment.

Proof of concept studies for siRNA delivery by nonionic surfactant vesicles: in vitro and in vivo evaluation of protein knockdown.

RNA interference is an effective and naturally occurring post-transcriptional gene regulatory mechanism. This mechanism involves the degradation of a target messenger RNA (mRNA) through the introduction of short interfering RNA (siRNA) that is complementary to the target mRNA. The application of siRNA-based therapeutics is limited by the development of an effective delivery system, as naked siRNA is unstable and cannot penetrate the cell membrane. In this study, we investigated the use of cationic niosomes (CN) prepared by microfluidic mixing for siRNA delivery. In an in vitro model, these vesicles were able to deliver anti-luciferase siRNA and effectively suppress luciferase expression in B16-F10 mouse melanoma cells. More importantly, in an in vivo mouse model, intratumoral administration of CN-carrying anti-luciferase siRNA led to significant suppression of luciferase expression compared with naked siRNA. Thus, we have established a novel and effective system for the delivery of siRNA both in vitro and in vivo, which shows high potential for future application of gene therapeutics.

Redox-sensitive, cholesterol-bearing PEGylated poly(propylene imine)-based dendrimersomes for drug and gene delivery to cancer cells.

Stimuli-responsive nanocarriers have attracted increased attention as materials that can facilitate drug and gene delivery in cancer therapy. The present study reports the development of redox-sensitive dendrimersomes comprising disulfide-linked cholesterol-bearing PEGylated dendrimers, which can be used as drug and gene delivery systems. Two disulfide-linked cholesterol-bearing PEGylated generation 3 diaminobutyric polypropylenimine dendrimers have been successfully synthesized via an in situ two-step reaction. They were able to spontaneously self-assemble into stable, cationic, nanosized vesicles (or dendrimersomes) with lower critical aggregation concentration values for high-cholesterol-bearing vesicles. These dendrimersomes were able to entrap both hydrophilic and hydrophobic dyes, and they also showed a redox-responsive sustained release of the entrapped guests in the presence of a glutathione concentration similar to that of a cytosolic reducing environment. The high-cholesterol-bearing dendrimersomes were found to have a higher melting enthalpy, increased adsorption tendency on mica surface, entrapping ability for a larger amount of hydrophobic drugs, and increased resistance to redox-responsive environments in comparison with their low-cholesterol counterpart. In addition, both dendrimersomes were able to condense more than 85% of the DNA at all the tested ratios for the low-cholesterol vesicles, and at dendrimer : DNA weight ratios of 1 : 1 and higher for the high-cholesterol vesicles. These vesicles resulted in an enhanced cellular uptake of DNA, by up to 15-fold when compared with naked DNA with low-cholesterol vesicles. As a result, they increased the gene transfection on the PC-3 prostate cancer cell line, with the highest transfection being obtained with low-cholesterol vesicle complexes at a dendrimer : DNA weight ratio of 5 : 1 and high-cholesterol vesicle complexes at a dendrimer : DNA weight ratio of 10 : 1. These transfection levels were about 5-fold higher than those observed when treated with naked DNA. These cholesterol-bearing PEGylated dendrimer-based vesicles are, therefore, promising as redox-sensitive drugs and gene delivery systems for potential applications in combination cancer therapies.

Targeted nonviral gene therapy in prostate cancer.

Prostate cancer is the second-most widespread cancer in men worldwide. Treatment choices are limited to prostatectomy, hormonal therapy, and radiotherapy, which commonly have deleterious side effects and vary in their efficacy, depending on the stage of the disease. Among novel experimental strategies, gene therapy holds great promise for the treatment of prostate cancer. However, its use is currently limited by the lack of delivery systems able to selectively deliver the therapeutic genes to the tumors after intravenous administration without major drawbacks. To remediate this problem, a wide range of nonviral delivery approaches have been developed to specifically deliver DNA-based therapeutic agents to their site of action. This review provides an overview of the various nonviral delivery strategies and gene therapy concepts used to deliver therapeutic DNA to prostate cancer cells, and focuses on recent therapeutic advances made so far.

PEGylation of polypropylenimine dendrimers: effects on cytotoxicity, DNA condensation, gene delivery and expression in cancer cells.

Diaminobutyric polypropylenimine (DAB) dendrimers have been shown to be highly efficient non-viral gene delivery systems for cancer therapy. However, their cytotoxicity currently limits their applications. To overcome this issue, PEGylation of DAB dendrimer, using various PEG molecular weights and dendrimer generations, has been attempted to decrease the cytotoxicity and enhance the DNA condensation, size and zeta potential, cellular uptake and transfection efficacy of these dendriplexes. Among all the PEGylated dendrimers synthesized, generation 3- and generation 4-DAB conjugated to low molecular weight PEG (2 kDa) at a dendrimer: DNA ratio of 20:1 and 10:1 resulted in an increase in gene expression on almost all tested cancer cells lines (by up to 3.2-fold compared to unmodified dendrimer in A431 cells). The highest level of ß-galactosidase gene expression (10.07 × 10-3 ± 0.09 × 10-3 U/mL) was obtained following treatment of B16F10-Luc cells with G4-dendrimer PEGylated with PEG2K at a dendrimer: DNA ratio of 20:1. These delivery systems significantly decreased cytotoxicity on B16F10-Luc cells, by more than 3.4-fold compared to unmodified dendrimer. PEGylated generations 3- and 4-DAB dendrimers are therefore promising gene delivery systems for cancer therapy, combining low cytotoxicity and high transfection efficacy.

Regression of prostate tumors after intravenous administration of lactoferrin-bearing polypropylenimine dendriplexes encoding TNF-α, TRAIL, and interleukin-12.

The possibility of using gene therapy for the treatment of prostate cancer is limited by the lack of intravenously administered delivery systems able to safely and selectively deliver therapeutic genes to tumors. Given that lactoferrin (Lf) receptors are overexpressed on prostate cancer cells, we hypothesized that the conjugation of Lf to generation 3-diaminobutyric polypropylenimine dendrimer would improve its transfection and therapeutic efficacy in prostate cancer cells. In this study, we demonstrated that the intravenous administration of Lf-bearing DAB dendriplexes encoding TNFα resulted in the complete suppression of 70% of PC-3 and 50% of DU145 tumors over one month. Treatment with DAB-Lf dendriplex encoding TRAIL led to tumor suppression of 40% of PC-3 tumors and 20% of DU145 tumors. The treatment was well tolerated by the animals. Lf-bearing generation 3-polypropylenimine dendrimer is therefore a highly promising delivery system for non-viral gene therapy of prostate cancer.

Tumor regression after intravenous administration of targeted vesicles entrapping the vitamin E α-tocotrienol.

The therapeutic potential of tocotrienol, a member of the vitamin E family of compounds with potent in vitro anti-cancer properties, is limited by its inability to specifically reach tumors following intravenous administration. The purpose of this study is to determine whether a novel tumor-targeted vesicular formulation of tocotrienol would suppress the growth of A431 epidermoid carcinoma and B16-F10 melanoma in vitro and in vivo. In this work, we demonstrated that novel transferrin-bearing multilamellar vesicles entrapping α-T3 resulted in a dramatically improved (by at least 52-fold) therapeutic efficacy in vitro on A431 cell line, compared to the free drug. In addition, the intravenous administration of tocotrienol entrapped in transferrin-bearing vesicles resulted in tumor suppression for 30% of A431 and 60% of B16-F10 tumors, without visible toxicity. Mouse survival was enhanced by >13days compared to controls administered with the drug solution only. This tumor-targeted, tocotrienol-based nanomedicine therefore significantly improved the therapeutic response in cancer treatment.

Enhanced gene expression in the brain following intravenous administration of lactoferrin-bearing polypropylenimine dendriplex.

The possibility of using gene therapy for the treatment of brain diseases such as brain cancer, Alzheimer's and Parkinson's diseases, is currently hampered by the lack of gene delivery systems able to cross the blood-brain barrier and deliver DNA to the brain following intravenous administration. On the basis that lactoferrin can effectively reach the brain by using specific receptors for crossing the blood-brain barrier, we propose to investigate if a lactoferrin-bearing generation 3-diaminobutyric polypropylenimine (DAB) dendrimer would allow the transport of plasmid DNA to the brain after intravenous administration. In this work, we demonstrated that the conjugation of lactoferrin to the dendrimer led to an enhanced DNA uptake by 2.1-fold in bEnd.3 murine brain capillary endothelial cells compared to the unmodified dendriplex in vitro. In vivo, the intravenous administration of lactoferrin-bearing DAB dendriplex resulted in a significantly increased gene expression in the brain, by more than 6.4-fold compared to that of DAB dendriplex, while decreasing gene expression in the lung and the kidneys. Gene expression in the brain was significantly higher than in any other major organs of the body. Lactoferrin-bearing generation 3 polypropylenimine dendrimer is therefore a highly promising delivery system for systemic gene delivery to the brain.