Development of cationic liposome formulations for intratracheal gene therapy of early lung cancer

99mTc-Labeled, Colistin Encapsulated, Theranostic Liposomes for Pseudomonas aeruginosa Infection

Infectious diseases are still the major issue not only due to antibiotic resistance but also causing deaths if not diagnosed at early-stages. Different approaches including nanosized drug delivery systems and theranostics are researched to overcome antibiotic resistance, decrease the side effects of antibiotics, improve the treatment response, and early diagnose. Therefore, in the present study, nanosized, radiolabeled with ^99mTc, colistin encapsulated, neutral and cationic liposome formulations were prepared as the theranostic agent for Pseudomonas aeruginosa infections. Liposomes exhibited appropriate physicochemical properties thanks to their nano-particle size (between 173 and 217 nm), neutral zeta potential value (about - 6.5 and 2.8 mV), as well as encapsulation efficiency of about 75%. All liposome formulations were radiolabeled with over 90% efficiency, and the concentration of stannous chloride was found as 1 mg.mL^-1 to obtain maximum radiolabeling efficiency. In alamar blue analysis, neutral liposome formulations were found more biocompatible compared with the cationic formulations. Neutral colistin encapsulated liposomes were found to be more effective against P. aeruginosa strain according to their time-dependent antibacterial effect, in addition to their highest bacterial binding capacity. As conclusion, theranostic, nanosized, colistin encapsulated, neutral liposome formulations were found as promising agents for the imaging and treating of P. aeruginosa infections.

What We Need to Know about Liposomes as Drug Nanocarriers: An Updated Review

Liposomes have been attracted considerable attention as phospholipid spherical vesicles, over the past 40 years. These lipid vesicles are valued in biomedical application due to their ability to carry both hydrophobic and hydrophilic agents, high biocompatibility and biodegradability. Various methods have been used for the synthesis of liposomes, so far and numerous modifications have been performed to introduce liposomes with different characteristics like surface charge, size, number of their layers, and length of circulation in biological fluids. This article provides an overview of the significant advances in synthesis of liposomes via active or passive drug loading methods, as well as describes some strategies developed to fabricate their targeted formulations to overcome limitations of the "first-generation" liposomes.

Pulmonary delivery of cationic liposomal hydroxycamptothecin and 5-aminolevulinic acid for chemo-sonodynamic therapy of metastatic lung cancer

Sonodynamic therapy (SDT) has been tried for cancer treatment; however, sonosensitizers are usually administered by injection, leading to low distribution in the tumor tissue and compromised therapeutic effect, even serious side effect. Here, we combined cationic liposomal hydroxycamptothecin (CLH) and 5-aminolevulinic acid (5-ALA) via intratracheal (i.t.) administration for the chemo-sonodynamic (Chemo-SDT) therapy of metastatic lung cancer. CLH was prepared from HCPT and the lipid mixture of soybean lecithin/cholesterol/octadecylamine with a film method. The optimal pre-incubation time of 5-ALA with tumor cells before ultrasound exposure was 4 h, for sake of sonosensitizer accumulation, i.e., protoporphyrin IX, the metabolite of 5-ALA. In vitro studies showed the higher cytotoxicity of Chemo-SDT compared to the other treatments, including i.t. CLH, intravenous (i.v.) CLH, and SDT alone. The combination of pulmonary delivery and Chemo-SDT showed the highest anticancer effect among the treatments on the metastatic lung tumor-bearing mice, which was judged according to the tumor appearance and pathological sections. The major anticancer mechanism of Chemo-SDT included the improved apoptosis of cancer cells and the enhanced production of reactive oxygen species, and more importantly, the synergy of chemotherapy and SDT. Pulmonary delivery of chemotherapeutics and sonosensitizers is a promising strategy for the treatment of lung cancer.

Colloidally Stable Small Unilamellar Stearyl Amine Lipoplexes for Effective BMP-9 Gene Delivery to Stem Cells for Osteogenic Differentiation

The biocompatibility of cationic liposomes has led to their clinical translation in gene delivery and their application apart from cancer to cardiovascular diseases, osteoporosis, metabolic diseases, and more. We have prepared PEGylated stearyl amine (pegSA) lipoplexes meticulously considering the physicochemical properties and formulation parameters to prepare single unilamellar vesicles (SUV) of < 100 nm size which retain their SUV nature upon complexation with pDNA rather than the conventional lipoplexes which show multilamellar nature. The developed PEGylated SA lipoplexes (pegSA lipoplexes) showed a lower N/P ratio (1.5) for BMP-9 gene complexation while maintaining the SUV character with a unique shape (square and triangular lipoplexes). Colloidal and pDNA complexation stability in the presence of electrolytes and serum indicates the suitability for intravenous administration for delivery of lipoplexes to bone marrow mesenchymal stem cells through sinusoidal vessels in bone marrow. Moreover, lower charge density of lipoplexes and low oxidative stress led to lower toxicity of lipoplexes to the C2C12 cells, NIH 3T3 cells, and erythrocytes. Transfection studies showed efficient gene delivery to C2C12 cells inducing osteogenic differentiation through BMP-9 expression as shown by enhanced calcium deposition in vitro, proving the potential of lipoplexes for bone regeneration. In vivo acute toxicity studies further demonstrated safety of the developed lipoplexes. Developed pegSA lipoplexes show potential for further in vivo preclinical evaluation to establish the proof of concept.

Genetic Modification of the Lung Directed Toward Treatment of Human Disease

Genetic modification therapy is a promising therapeutic strategy for many diseases of the lung intractable to other treatments. Lung gene therapy has been the subject of numerous preclinical animal experiments and human clinical trials, for targets including genetic diseases such as cystic fibrosis and α1-antitrypsin deficiency, complex disorders such as asthma, allergy, and lung cancer, infections such as respiratory syncytial virus (RSV) and Pseudomonas, as well as pulmonary arterial hypertension, transplant rejection, and lung injury. A variety of viral and non-viral vectors have been employed to overcome the many physical barriers to gene transfer imposed by lung anatomy and natural defenses. Beyond the treatment of lung diseases, the lung has the potential to be used as a metabolic factory for generating proteins for delivery to the circulation for treatment of systemic diseases. Although much has been learned through a myriad of experiments about the development of genetic modification of the lung, more work is still needed to improve the delivery vehicles and to overcome challenges such as entry barriers, persistent expression, specific cell targeting, and circumventing host anti-vector responses.

DNA amplification in neutral liposomes for safe and efficient gene delivery

In general, traditional gene carriers contain strong cationic charges to efficiently load anionic genes, but this cationic character also leads to destabilization of plasma membranes and causes severe cytotoxicity. Here, we developed a PCR-based nanofactory as a safe gene delivery system. A few template plasmid DNA can be amplified by PCR inside liposomes about 200 nm in diameter, and the quantity of loaded genes highly increased by more than 8.8-fold. The liposome membrane was composed of neutral lipids free from cationic charges. Consequently, this system is nontoxic, unlike other traditional cationic gene carriers. Intense red fluorescent protein (RFP) expression in CHO-K1 cells showed that the amplified genes could be successfully transfected to cells. Animal experiments with the luciferase gene also showed in vivo gene expression by our system without toxicity. We think that this PCR-based nanofactory system can overcome the toxicity problem that is the critical limitation of current gene delivery to clinical application.

Stimuli-responsive polymers in gene delivery

Recent interest in clinical therapy has been directed to deliver nucleic acids (DNA, RNA or short-chain oligonucleotides) that alter gene expression within a specific cell population, thereby manipulating cellular processes and responses, which in turn stimulate immune responses or tissue regeneration, or blocks expression at the level of transcription or translation for treatment of several diseases. Both ex vivo and in vivo gene delivery can be achieved mostly by using a delivery system (vector). Viral vectors exhibit high gene expression, but also have very significant side effects. Mainly cationic polymeric systems are used as nonviral vectors, although usually with low levels of transfection. Through the use of stimuli-responsive polymers as novel vectors for gene delivery, two benefits can be obtained: high gene expression efficiency and more selective gene expression.

Therapeutic liposomal dry powder inhalation aerosols for targeted lung delivery

Therapeutic liposomal powders (i.e., lipospheres and proliposomes) for dry powder inhalation aerosol delivery, formulated with phospholipids similar to endogenous lung surfactant, offer unique opportunities in pulmonary nanomedicine while offering controlled release and enhanced stability. Many pulmonary diseases such as lung cancer, tuberculosis (TB), cystic fibrosis (CF), bacterial and fungal lung infections, asthma, and chronic obstructive pulmonary disease (COPD) could greatly benefit from this type of pulmonary nanomedicine approach that can be delivered in a targeted manner by dry powder inhalers (DPIs). These delivery systems may require smaller doses for efficacy, exhibit reduced toxicity, fewer side effects, controlled drug release over a prolonged time period, and increased formulation stability as inhaled powders. This state-of-the-art review presents these novel aspects in depth.

Liposomal formulations of Etoposide and Docetaxel for p53 mediated enhanced cytotoxicity in lung cancer cell lines

The objective of present investigation was to develop and assess comparative enhancement in cytotoxicity of liposomal Etoposide and Docetaxel in non-small cell lung cancer cell lines after pre-treatment and co-administration of p53 tumor suppressor gene and to assess direct lung targeting of optimized formulations by dry powder inhaler technology. Cationic liposomes with and without drug were prepared and allowed to form p53-lipoplex for undertaking cytotoxicity studies in H-1299 (p53 null) and A-549 (p53 wt) cell lines. The optimized lipoplexes showed average size of 200-350 nm, zeta potential of 25-32 mV and sustained drug release up to 16-24 h. The developed liposomes and lipoplexes showed significant intracellular uptake and demonstrated enhanced cytotoxicity of 13-28 % after p53-drug co-administration and 41-63 % after p53 pre-treatment. The p53 mediated enhanced cytotoxicity by increased apoptosis and necrosis was also confirmed using Annexin V - FITC assay. The increased apoptosis suggested restored p53 function and reduced anti-apoptotic drug resistance theirby causing cell sensitization and synergism towards cytotoxicity. The studies conducted above demonstrated significant cell chemo-sensitization after p53 pre-treatment followed by Etoposide/Docetaxel liposomes administration than p53-Etoposide or p53-Docetaxel lipoplex co-administration; more significantly in Docetaxel and in H 1299 cell line. All the formulations when developed as dry powder inhalers showed significant in vitro lung deposition pattern in cascade impactor with fine particle faction of 33-37%. The study opens up a new strategy to treat lung cancer especially in cases of drug resistance. Moreover direct delivery to lung may provide an important role in complete remission of the disease due to target specificity.

Protection against TNFα-dependent liver toxicity by intraperitoneal liposome delivered DsiRNA targeting TNFα in vivo

Tumor necrosis factor-alpha (TNFα) is a classic proinflammatory cytokine implicated in the pathogenesis of several autoimmune and inflammatory diseases including viral encephalitis. Macrophages being major producers of TNFα are thus attractive targets for in vivo RNA interference (RNAi) mediated down regulation of TNFα. The application of RNAi technology to in vivo models however presents obstacles, including rapid degradation of RNA duplexes in plasma, insufficient delivery to the target cell population and toxicity associated with intravenous administration of synthetic RNAs and carrier compounds. We exploited the phagocytic ability of macrophages for delivery of Dicer-substrate small interfering RNAs (DsiRNAs) targeting TNFα (DsiTNFα) by intraperitoneal administration of lipid-DsiRNA complexes that were efficiently taken up by peritoneal macrophages and other phagocytic cells. We report that DsiTNFα-lipid complexes delivered intraperitoneally altered the disease outcome in an acute sepsis model. Down-regulation of TNFα in peritoneal CD11b+ monocytes reduced liver damage in C57BL/6 mice and significantly delayed acute mortality in mice treated with low dose LPS plus d-galactosamine (D-GalN).

Liposomal nanomedicine for breast cancer therapy

Liposomes are well-established nanocarriers for improving the therapeutic index of anticancer agents. A remarkable understanding in the pathophysiology of breast cancer progression has emerged with information on the involved specific biomolecules, which may serve as molecular targets for its therapy. Hormonal and nonhormonal receptors can both be exploited for targeting to breast cancer cells. Targeted delivery of cytotoxic drugs using liposomes is a novel approach for breast cancer therapy. In the present article, we summarize molecular targets present on the breast cancer cells. Recent developments in liposome-based delivery of bioactives for selective treatments of breast cancer are discussed. In addition, utilization of bioenvironmental conditions of tumor for liposome-based targeted delivery is also summed up.

Gene therapy with recombinant adenovirus encoding endostatin encapsulated in cationic liposome in coxsackievirus and adenovirus receptor-deficient colon carcinoma murine models

Adenovirus (Ad)-based antiangiogenesis gene therapy is a promising approach for cancer treatment. Downregulation or loss of coxsackievirus and adenovirus receptor (CAR) is often detected in various human cancers, which hampers adenoviral gene therapy approaches. Cationic liposome-complexed adenoviral vectors have been proven useful in CAR-deficient cells to enhance therapeutic gene transfer in vivo. Here, we investigated the antitumor effects of recombinant adenovirus encoding endostatin (Ad-hE) encapsulated in cationic liposome (Ad-hE/Lipo) on CAR-deficient CT26 colon carcinoma murine models. In vitro, Ad-hE/Lipo enhanced adenovirus transfection in CAR-deficient cells (CT26), and endostatin gene expression was measured by both qualitative and quantitative detection. In addition, an antibody neutralizing assay indicated that neutralizing serum inhibited naked adenovirus 5 (Ad5) at rather higher dilution than the complexes of Ad5 and cationic liposomes (Ad5-CL), which demonstrated that Ad5-CL was more capable of protecting Ad5 from neutralization. In vivo, Ad-hE/Lipo treatment in the murine CT26 tumor model by intratumoral injection resulted in marked suppression of tumor growth and prolonged survival time, which was associated with a decreased number of microvessels and increased apoptosis of tumor cells. In conclusion, recombinant endostatin adenovirus encapsulated with cationic liposome effectively inhibited CAR-deficient tumor growth through an antiangiogenic mechanism in murine models without marked toxicity, thus showing a feasible strategy for clinical applications.

Intratracheally administered 5-azacytidine is effective against orthotopic human lung cancer xenograft models and devoid of important systemic toxicity

INTRODUCTION

Hypermethylation of key tumor suppressor genes plays an important role in lung carcinogenesis. The purpose of this study is to explore the therapeutic potential of regional administration (via the airways) of the demethylating agent 5-azacytidine (5-Aza) for the treatment of early lung cancer.

PATIENTS AND METHODS

We administered 5-Aza solution directly into the trachea in imprinting control region (ICR) mice (to study its toxicity) and in nude mice bearing orthotopic human lung cancer xenografts (to assess its antitumor activity).

RESULTS

In vitro, 5-Aza inhibited the growth of human lung cancer cell lines H226, H358, and H460 in a dose-dependent manner. The concentrations to inhibit cell growth by 50% (IC50) were about 0.6-4.9 µg/mL. 5-Azacytidine reversed hypermethylation in the promoter of tumor suppressor gene RASSF1a in the H226 cells at a 6000-fold lower concentration than its IC50. In animal studies, intratracheal (I.T.) administration of 90 mg/kg 5-Aza (the maximum tolerated dose of 5-Aza intravenous injection [I.V.]) resulted in moderate pulmonary toxicity and 5-fold reduced myelosuppression compared with the same dose of I.V. 5-Aza. Using an optimized multiple dose schedule, I.T. 5-Aza was about 3-fold more effective than I.V. 5-Aza in prolonging the survival of mice bearing orthotopic H460 and H358 xenografts, and did not cause any detectable toxicity.

CONCLUSION

5-Azacytidine can reverse the hypermethylation in the human lung cancer cell lines at a nontoxic dose. Regional administration to the airways enhances the therapeutic index of 5-Aza by 75-fold. The potential of regional administration of 5-Aza (including by aerosolization) for the treatment of advanced bronchial premalignancy deserves further investigation.

In vivo gene delivery by cationic tetraamino fullerene

Application of nanotechnology to medical biology has brought remarkable success. Water-soluble fullerenes are molecules with great potential for biological use because they can endow unique characteristics of amphipathic property and form a self-assembled structure by chemical modification. Effective gene delivery in vitro with tetra(piperazino)fullerene epoxide (TPFE) and its superiority to Lipofectin have been described in a previous report. For this study, we evaluated the efficacy of in vivo gene delivery by TPFE. Delivery of enhanced green fluorescent protein gene (EGFP) by TPFE on pregnant female ICR mice showed distinct organ selectivity compared with Lipofectin; moreover, higher gene expression by TPFE was found in liver and spleen, but not in the lung. No acute toxicity of TPFE was found for the liver and kidney, although Lipofectin significantly increased liver enzymes and blood urea nitrogen. In fetal tissues, neither TPFE nor Lipofectin induced EGFP gene expression. Delivery of insulin 2 gene to female C57/BL6 mice increased plasma insulin levels and reduced blood glucose concentrations, indicating the potential of TPFE-based gene delivery for clinical application. In conclusion, this study demonstrated effective gene delivery in vivo for the first time using a water-soluble fullerene.

GFP expression by intracellular gene delivery of GFP-coding fragments using nanocrystal quantum dots

Gene therapy is an attractive approach to supplement a deficient gene function. Although there has been some success with specific gene delivery using various methods including viral vectors and liposomes, most of these methods have a limited efficiency or also carry a risk for oncogenesis. We herein report that quantum dots (QDs) conjugated with nuclear localizing signal peptides (NLSP) successfully introduced gene-fragments with promoter elements, which promoted the expression of the enhanced green fluorescent protein (eGFP) gene in mammalian cells. The expression of eGFP protein was observed when the QD/gene-construct was added to the culture media. The gene-expression efficiency varied depending on multiple factors around QDs, such as (1) the reading direction of the gene-fragments, (2) the quantity of gene-fragments attached on the surface of the QD-constructs, (3) the surface electronic charges varied according to the structure of the QD/gene-constructs, and (4) the particle size of QD/gene complex varied according to the structure and amounts of gene-fragments. Using this QD/gene-construct system, eGFP protein could be detected 28 days after the gene-introduction whereas the fluorescence of QDs had disappeared. This system therefore provides another method for the intracellular delivery of gene-fragments without using either viral vectors or specific liposomes.

Biomedical nanotechnology for cancer

Nanotechnology may hold the key to controlling many devastating diseases. In the fight against the pain, suffering, and death due to cancer, nanotechnology will allow earlier diagnosis and even prevention of malignancy at premalignant stages, in addition to providing multimodality treatment not possible with current conventional techniques. This review discusses nanotechnology already used in diagnostic and therapeutic applications for cancer. Also addressed are theoretic and evolving uses of nanotechnology, including multifunctional nanoparticles for imaging and therapy, nanochannel implants for controlled release of drugs, nanoscale devices for evaluation of proteomics and genomics, and diagnostic techniques that take advantage of physical changes in diseased tissue.

p53 Aerosol Formulation with Low Toxicity and High Efficiency for Early Lung Cancer Treatment

PURPOSE

To develop an optimal nonviral aerosol formulation for locoregional treatment of early lung cancer.

EXPERIMENTAL DESIGN

The formulation was made of polylysine/protamine combination (AND) as the carrier and p53 gene (p53sm) as therapeutic agent. To estimate the aerosol deposition, the aerodynamic size of the AND-p53sm was measured with extrusion-precipitation method. To accurately determine the dose, the aerosol efficiency in mice was measured with a fluorescent dye. The transfection efficiency and DNA protection function of the aerosolized formulation in cultured cells and mouse lungs were detected with reporter gene assays and/or reverse transcription-PCR. The preclinical safety and efficacy of AND-p53sm were studied in healthy mice and mice bearing orthotopic human non-small-cell lung cancer (NSCLC) xenograft.

RESULTS

After aerosolization, AND is 3- to 17-fold more effective than commonly used PEI or cationic lipid formulations in transfecting the NSCLC cells (relative light units, 1,494 versus 534 and 86; P < 0.003). Aerodynamic size of AND-p53sm ranged 0.2 to 3 mum is the optimal aerosol droplets for deposition in the entire human respiratory tract. Significant gene expression was detected in the lungs of mice given aerosolized AND-p53sm and AND-luciferase. Aerosolized AND-p53sm significantly prolonged the life of mice bearing orthotopic human NSCLC xenografts, and it was more effective than an optimal i.v. cisplatin chemotherapy (increased life span, 93% versus 25%; P = 0.014). Inhalation of AND produced low and reversible pulmonary toxicity and no systemic toxicity.

CONCLUSIONS

This optimal formulation is suitable for delivering biological materials to human lung with aerosol administration. This therapeutic strategy is an option for patients with early lung cancer and bronchoalveolar carcinoma.

Amphiphilic triblock copolymer poly(p-dioxanone-co-L-lactide)-block-poly(ethylene glycol), enhancement of gene expression and inhibition of lung metastasis by aerosol delivery

We describe the development of an aerosol system for topical gene delivery to the lungs of C57BL/6 mice. This system is based on the combination of the commercial cationic lipid Lipofectin with a novel amphiphilic triblock copolymer, poly(p-dioxanone-co-L-lactide)-block-poly(ethylene glycol) (PPDO/PLLA-b-PEG, and abbreviated in the text as polymeric micelles). After optimizing conditions for DNA delivery to the lungs of mice using the combination of polymeric micelles with Lipofectin and LacZ DNA, we used the Lipofectin/polymeric micelle system to deliver the tumor suppressor gene PTEN to the lungs of C57BL/6 mice bearing the B16-F10 melanoma. Lipofectin/PTEN/polymeric micelles significantly improved gene expression of PTEN in the lungs of mice with no evidence of cell toxicity or acute inflammation. Importantly, lung metastasis, as measured by lung weight, was significantly reduced (P<0.001), as were total tumor foci in the lungs (P<0.001) and size of individual tumor nodules in animals treated with Lipofectin/PTEN/polymeric micelles compared with control animals. Survival time was also extended. These results suggest that the Lipofectin/polymeric micelle system is appropriate for enhancing gene delivery in vivo and that it can be applied as a non-invasive gene therapy for lung cancer.

The effect of PS content on the ability of natural membranes to fuse with positively charged liposomes and lipoplexes

Supramolecular aggregates containing cationic lipids have been widely used as transfection mediators due to their ability to interact with negatively charged DNA molecules and biological membranes. First steps of the process leading to transfection are partly electrostatic, partly hydrophobic interactions of liposomes/lipoplexes with cell and/or endosomal membrane. Negatively charged compounds of biological membranes, namely glycolipids, glycoproteins and phosphatidylserine (PS), are responsible for such events as adsorption, hemifusion, fusion, poration and destabilization of natural membranes upon contact with cationic liposomes/lipoplexes. The present communication describes the dependence of interaction of cationic liposomes with natural and artificial membranes on the negative charge of the target membrane, charges which in most cases were generated by charging the PS content or its exposure. The model for the target membranes were liposomes of variable content of PS or PG (phosphatidylglycerol) and erythrocyte membranes in which the PS and other anionic compound content/exposure was modified in several ways. Membranes of increased anionic phospholipid content displayed increased fusion with DOTAP (1,2-dioleoyl-3-trimethylammoniumpropane) liposomes, while erythrocyte membranes partly depleted of glycocalix, its sialic acid, in particular, showed a decreased fusion ability. The role of the anionic component is also supported by the fact that erythrocyte membrane inside-out vesicles fused easily with cationic liposomes. The data obtained on erythrocyte ghosts of normal and disrupted asymmetry, in particular, those obtained in the presence of Ca(2+), indicate the role of lipid flip-flop movement catalyzed by scramblase. The ATP-depletion of erythrocytes also induced an increased sensitivity to hemoglobin leakage upon interactions with DOTAP liposomes. Calcein leakage from anionic liposomes incubated with DOTAP liposomes was also dependent on surface charge of the target membranes. In all experiments with the asymmetric membranes the fusion level markedly increased with an increase of temperature, which supports the role of membrane lipid mobility. The decrease in positive charge by binding of plasmid DNA and the increase in ionic strength decreased the ability of DOTAP liposomes/lipoplexes to fuse with erythrocyte ghosts. Lower pH promotes fusion between erythrocyte ghosts and DOTAP liposomes and lipoplexes. The obtained results indicate that electrostatic interactions together with increased mobility of membrane lipids and susceptibility to form structures of negative curvature play a major role in the fusion of DOTAP liposomes with natural and artificial membranes.

Successful in vivo tumor targeting of prostate-specific membrane antigen with a highly efficient J591/PEI/DNA molecular conjugate

We have utilized a novel polyethylenimine (PEI)/DNA-betagal vector to investigate the specificity and efficiency of immuno-targeting prostate-specific membrane antigen (PSMA). Coupling of the PSMA-specific monoclonal antibody, J591, to the vector was facilitated via the high-affinity interaction between phenyl(di)boronic acid and salicylhydroxamic acid molecules. Highly efficient gene delivery by this prostate cancer (PCA)-targeted J591/polyethylene glycol (PEG)/PEI/DNA-betagal vector was demonstrated in PSMA-positive cells relative to controls, resulting in significant growth inhibition in vitro when the J591/PEG/PEI/DNA-p53 was used. Competition with free antibody resulted in about 90% reduction in both J591 internalization and betagal gene delivery, indicating specificity for PSMA-positive cells. More importantly, testing the efficiency of the J591/PEG/PEI/DNA-betagal targeting vector in an orthotopic PCA model in nude mice resulted in up to a 20-fold increase in gene delivery over the untargeted vector controls. The in vivo organ distribution profile also revealed betagal expression predominantly in the tumor, which was more than 1 log higher than the next highest level of expression in the lung. Furthermore, with the targeted vector containing the gene for yellow fluorescent protein or biotinylated J591, we further demonstrate in vivo that vector-mediated gene delivery is specific for both tumor cells and tumor-associated neovasculature in PSMA-positive tumors. These results suggest the potential for further optimization of this novel vector in the context of therapeutic gene delivery.

Identification and characterization of a novel peptide ligand of epidermal growth factor receptor for targeted delivery of therapeutics

Epidermal growth factor receptor (ErbB1, EGFR) is overexpressed in a variety of human cancer cells. It has been considered as a rational target for drug delivery. To identify novel ligands with specific binding capabilities to EGFR, we screened a phage display peptide library and found an enriched phage clone encoding the amino acid sequence YHWYGYTPQNVI (designated as GE11). Competitive binding assay and Scatchard analysis revealed that GE11 peptide bound specifically and efficiently to EGFR with a dissociation constant of approximately 22 nM, but with much lower mitogenic activity than with EGF. We showed that the peptides were internalized preferentially into EGFR highly expressing cells, and they accumulated in EGFR overexpressing tumor xenografts after i.v. delivery in vivo. In gene delivery studies, GE11-conjugated polyethylenimine (PEI) vectors were less mitogenic, but still quite efficient at transfecting genes into EGFR highly expressing cells and tumor xenografts. Taken together, GE11 is a potentially safe and efficient targeting moiety for selective drug delivery systems mediated through EGFR.

Novel cationic cardiolipin analogue-based liposome for efficient DNA and small interfering RNA delivery in vitro and in vivo

Cationic liposomes have been successfully used as an alternative approach to viral systems to deliver nucleic acids. However, high toxicity and inconsistent transfection efficiency have been associated with the currently available liposomes. Therefore, a novel cationic liposome was developed based on a synthetic cationic cardiolipin analogue (CCLA) to test the DNA transfection efficiency. This CCLA-based liposome was also used to determine the therapeutic efficacy of c-raf small interfering RNA (siRNA) in mice. In this report, we showed that the CCLA-based liposome was less toxic and effectively transfected reporter genes in vitro and in vivo. The transfection efficiency in mice was seven-fold higher than the commercially available DOTAP-based liposome. In addition, c-raf siRNA in the presence of CCLA-based liposome induced up to 62% of growth inhibition in cancer cells. Treatment of c-raf siRNA/CCLA complex in SCID mice bearing human breast xenograft tumors resulted in 73% of tumor growth suppression as compared to free c-raf siRNA group. In conclusion, a novel CCLA-based liposome showed less toxicity and broad usage both in vitro and in vivo with DNA and siRNA.

Tumor-specific gene delivery mediated by a novel peptide-polyethylenimine-DNA polyplex targeting aminopeptidase N/CD13

We have developed a novel polyethylenimine (PEI)-DNA vector formulation that is capable of efficient tumor-specific delivery after intravenous administration to nude mice. To further increase the specificity of delivery, we have attached the peptide CNGRC to the vector, which is specific for aminopeptidase N (CD13). The strategy for coupling this peptide to PEI was based on a novel method involving the strong affinity between phenyl(di)boronic acid (PDBA) and salicylhydroxamic acid (SHA) as well as a polyethylene glycol (PEG) linker to reduce steric hindrance between the vector and the peptide. In vitro assessment of targeting by the CNGRC/PEG/PEI/DNA vector carrying a beta-galactosidase (beta-Gal)-expressing plasmid showed as much as a 5-fold increase in transduction, relative to the untargeted PEG/PEI/DNA-betagal vector, of CD13-positive lung cancer, fibrosarcoma, bladder cancer, and human umbilical vein endothelial cells. Competition with free peptide resulted in up to a 90% reduction in delivery, indicating that gene delivery was specific for CD13-positive cells. Intravenous administration of the CNGRC/PEG/PEI/DNA-betagal vector to nude mice bearing subcutaneous tumors resulted in as much as a 12-fold increase in beta-Gal expression in tumors as compared with expression in either lungs or tumors from animals treated with the original PEI/DNA-betagal vector. In vivo transduction analysis using the CNGRC/PEG/PEI/DNA vector to target the intravenous delivery of a yellow fluorescence protein (YFP)-expressing plasmid to subcutaneous H1299 tumors confirmed delivery of YFP to both tumor cells and tumor endothelial cells. The use of this peptide to further increase tumor-specific delivery mediated by our novel PEI/DNA vector now provides a basis for developing tumor-targeted gene therapies for use in the clinical treatment of cancer.

Delivery systems for pulmonary gene therapy

Delivery of therapeutic genes to the lungs is an attractive strategy to correct a variety of pulmonary dysfunctions such as cystic fibrosis, alpha-1 antitrypsin deficiency, pulmonary hypertension, asthma, and lung cancer. Different delivery routes such as intratracheal instillation, aerosol and intravenous injection have been utilized with varying degrees of efficiency. Both viral and non-viral vectors, with their respective strengths and weaknesses, have achieved significant levels of transgene expression in the lungs. However, the application of gene therapy for the treatment of pulmonary disease has been handicapped by various barriers to the delivery vectors such as serum proteins during intravenous delivery, and surfactant proteins and mucus in the airway lumen during topical application of therapeutic genes. Immune and cytokine responses against the delivery vehicle are also major problems encountered in pulmonary gene therapy. Despite these shortcomings much progress has been made to enhance the efficiency, as well as lower the toxicity of gene therapy vehicles in the treatment of pulmonary disorders such as cystic fibrosis, lung cancer and asthma.

Carrier-based strategies for targeting protein and peptide drugs to the lungs

With greater interest in delivery of protein and peptide-based drugs to the lungs for topical and systemic activity, a range of new devices and formulations are being investigated. While a great deal of recent research has focused on the development of novel devices, attention must now be paid to the formulation of these macromolecular drugs. The emphasis in this review will be on targeting of protein/peptide drugs by inhalation using carriers and ligands.

An overview of current delivery systems in cancer gene therapy

The main objective in gene therapy is the development of efficient, non-toxic gene carriers that can encapsulate and deliver foreign genetic materials into specific cell types such as cancerous cells. During the past two decades, enormous research in the area of gene delivery has been conducted worldwide, in particular for cancer gene therapy application. Viral vectors are biological systems derived from naturally evolved viruses capable of transferring their genetic materials into the host cells. Many viruses including retrovirus, adenovirus, herpes simplex virus (HSV), adeno-associated virus (AAV) and pox virus have been modified to eliminate their toxicity and maintain their high gene transfer capability. The limitations associated with viral vectors, however, in terms of their safety, particularly immunogenicity, and in terms of their limited capacity of transgenic materials, have encouraged researchers to increasingly focus on non-viral vectors as an alternative to viral vectors. Non-viral vectors are generally cationic in nature. They include cationic polymers such as poly(ethylenimine) (PEI) and poly(L-lysine) (PLL), cationic peptides and cationic liposomes. The newly described liposomal preparation LPD (liposomes/protamine/DNA), for example, has shown superiority over conventional liposomes/DNA complexes (lipoplexes). Although non-viral vectors are less efficient than viral ones, they have the advantages of safety, simplicity of preparation and high gene encapsulation capability. This article reviews the most recent studies highlighting the advantages and the limitations of various types of gene delivery systems used in cancer gene therapy.

Gene transfections with p53 and p21 inhibit cell proliferation, collagen type I, leukemia inhibitory factor, and tumor necrosis factor-α expression in leiomyoma cells

OBJECTIVE

To transfect the p53 and p21 gene into the leiomyoma cells isolated from patients and observe their influence on the cell proliferation, leukemia inhibitory factor production, and gene expression of collagen type I as well as tumor necrosis factor-alpha (TNF-alpha) of cultured cells.

DESIGN

Prospective study.

SETTING

An assisted reproductive technology (ART) and genetic unit of a medical center.

PATIENT(S)

Leiomyoma cells isolated from leiomyoma tissue of 12 patients were divided into three groups: [1]. vehicle DNA, [2]. p53 gene, and [3]. p21 gene transfections.

INTERVENTION(S)

The pcDNA3.1 was used as vector to carry p53 and p21 genes for transfer. After gene transfection, RNAs of the leiomyoma cells were extracted for further analyses of gene expression.

MAIN OUTCOME MEASURE(S)

Relative cell numbers were determined by 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide (MTT) assay. The leukemia inhibitory factor (LIF) concentration was determined with ELISA. Gene expressions of collagen type I and TNF-alpha were detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Gene expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an internal control. The cell proliferation, LIF production, as well as gene expressions of collagen type I and TNF-alpha in each group were compared.

RESULTS

Relative cell numbers (%)/LIF production (in picograms per milliliter) in each group were: [1]. 100/58, [2]. 71/43, and [3]. 106/65. The ratios of gene expression of collagen type I/TNF-alpha with GAPDH in each group were: [1]. 1.64/0.335, [2]. 1.25/0.434, and [3]. 1.77/0.234.

CONCLUSION(S)

Transfection with p53 significantly inhibits proliferation of leiomyoma cells and decreases collagen type I gene expression and LIF production. The p21 transfection inhibits TNF-alpha gene expression.

Stable polyplexes based on arginine-containing oligopeptides for in vivo gene delivery

In this study, we investigated to what extent the stability and transduction capacity of polyplexed DNA can be improved by optimizing the condensing peptide sequence. We have synthesized a small library of cationic peptides, at which the lysine/arginine ratio and the cation charge were varied. All peptides were able to compact DNA, at which polyplexes of short lysine-rich sequences were considerably larger than those of elongated or arginine-rich peptides (GM102 and GM202). In addition, the arginine-rich peptides GM102 and GM202 rendered the polyplexes resistant to plasma incubation or DNase I-mediated digestion. While all peptides were found to improve the transfection efficiency in HepG2 cells, only the GM102- and GM202-derived polyplexes could be specifically targeted to HepG2 cells by incorporation of a ligand-derivatized YKAK(8)WK peptide. We propose that GM102 and GM202 combine the advantage of small condensing peptides to give small-sized polyplexes with the superior stability of condensing polymers, which makes GM102 and GM202 excellent candidates for future in vivo gene therapy studies.

Gene therapy of lung cancer

It is estimated that there will be 157,200 deaths from lung cancer in 2003. Current regimens of surgery, chemotherapy and radiation have not significantly changed overall 5-year survival rates for this disease. Thanks to intensive molecular studies over the last three decades, new targets for treatment have been identified, including replacement of tumor suppressor genes, prevention of angiogenesis and tumor growth, and regulation of programmed cell death. Promising advances have been made but obstacles still abound before effective use of these strategies at the patient bedside can occur. One area of concentration lies in developing more accurate and complete delivery of the therapeutic constructs. In the evolution of gene therapy approaches, from beginning theory to translational research, investigators in thoracic malignancies have played a leading role, utilizing a number of methods and delivery vehicles. The objective of this review is to discuss some of the major molecular targets available for manipulation in lung cancer, describe vectors and techniques currently used by thoracic researchers to deliver therapy, and provide the p53 model as an example of progression from bench research to clinical treatment.

Enhanced p53 gene transfer to human ovarian cancer cells using the cationic nonviral vector, DDC

OBJECTIVE

Previously we have formulated a new cationic liposome, DDC, composed of dioleoyltrimethylamino propane (DOTAP), 1,2-dioeoyl-3-phosphophatidylethanolamine (DOPE), and cholesterol (Chol), and it efficiently delivered plasmid DNA into ovarian cancer cells. Mutations in the p53 tumor suppressor gene are the most common molecular genetic abnormalities to be described in ovarian cancer. However, there has been so far no report of nonviral vector-mediated p53 gene deliveries in ovarian cancer. In this study, wild-type p53 DNA was transfected into the ovarian cancer cells, using the DDC as a nonviral vector and the expression and activity of p53 gene were evaluated both in vitro and in vivo.

METHOD

DDC liposomes were prepared by mixing DOTAP:DOPE:Chol in a 1:0.7:0.3 molar ratio using the extrusion method. Plasmid DNA (pp53-EGFP) and DDC complexes were transfected into ovarian carcinoma cells (OVCAR-3 cells) and gene expression was determined by reverse transcription-polymerase chain reaction and Western blot analysis. The cellular growth inhibition and apoptosis of DDC-mediated p53 transfection were assessed by trypan blue exclusion assay and annexin-V staining, respectively. The OVCAR-3 cells treated with DDC/pp53-EGFP complexes were inoculated into female balb/c nude mice and tumor growth was observed.

RESULTS

The transfection of liposome-complexed p53 gene resulted in a high level of wild-type p53 mRNA and protein expressions in OVCAR-3 cells. In vitro cell growth assay showed growth inhibition of cancer cells transfected with DDC/pp53-EGFP complexes compared with the control cells. The reestablishment of wild-type p53 function in ovarian cancer cells restored the apoptotic pathway. Following the inoculation of DDC/pp53-EGFP complexes, the volumes of tumors in nude mice were significantly reduced more than 60% compared to the control group.

CONCLUSION

The DDC-mediated p53 DNA delivery may have the potential for clinical application as nonviral vector-mediated ovarian cancer therapy due to its effective induction of apoptosis and tumor growth inhibition.

The role of new agents in the treatment of non-small cell lung cancer

Lung cancer is one of the most frequent causes of cancer deaths worldwide. Non-small cell lung cancer (NSCLC) accounts for approximately 80% of cases and no curative treatment is available for the advanced stages of disease (stages III and IV), which comprise the majority of cases. Current treatment regimens with standard chemotherapy offer only a limited survival benefit, and, therefore, the development of new therapeutic strategies is needed. Novel chemotherapeutic drugs such as the epothilones, MEN 10755 and S-1 are being studied in patients with advanced stages of disease. Furthermore, a large number of therapies targeted against critical biological abnormalities in NSCLC are being investigated in clinical trials. The latter approach includes inhibition of growth factors, interference with abnormal signal transduction, inhibition of angiogenesis and gene replacement therapy. Promising results have thus far been obtained with some of these therapies. This review describes the role of new therapeutic agents in the treatment of NSCLC.

In vivo gene transfer of leukemia inhibitory factor (LIF) into mouse endometrium

PURPOSE

Leukemia inhibitory factor (LIF) is important for embryogenesis and implantation. We aimed to transfect LIF gene into the mouse endometrium.

MATERIALS AND METHODS

Expression plasmids carried LIF and luciferase genes for transfer. After superovulation, 100 ICR mice were mated with vasectomized mice. Then LIF-liposome (Group 1) and luciferase-liposome complexes (Group 2) were injected into their uterine lumen (Day 0). Endometrial LIF and luciferase expressions were detected by reverse transcription-polymerase chain reaction on Days 0-4 post gene transfer. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an internal control to normalize the gene transfection.

RESULTS

LIF mRNA and luciferase activities reached the peak expression on Day 3. In Group 1, the ratios of LIF/GADPH on Days 1-4 were 0.414, 1.096, 1.162, and 0.782. In Group 2. LIF/GADPH on Days 1-4 were 0.24, 0.22, 0.35, and 0.32.

CONCLUSIONS

Mouse endometrium could be effectively transfected with liposome-DNA mixtures. Endometrial LIF transfer via liposome may be effective in human.

Vehicles for oligonucleotide delivery to tumours

The vasculature of a tumour provides the most effective route by which neoplastic cells may be reached and eradicated by drugs. The fact that a tumour's vasculature is relatively more permeable than healthy host tissue should enable selective delivery of drugs to tumour tissue. Such delivery is relevant to carrier-mediated delivery of genetic medicine to tumours. This review discusses the potential of delivering therapeutic oligonucleotides (ONs) to tumours using cationic liposomes and cyclodextrins (CyDs), and the major hindrances posed by the tumour itself on such delivery. Cationic liposomes are generally 100-200 nm in diameter, whereas CyDs typically span 1.5 nm across. Cationic liposomes have been used for the introduction of nucleic acids into mammalian cells for more than a decade. CyD molecules are routinely used as agents that engender cholesterol efflux from lipid-laden cells, thus having an efficacious potential in the management of atherosclerosis. A recent trend is to employ these oligosaccharide molecules for delivering nucleic acids in cells both in-vitro and in-vivo. Comparisons are made with other ON delivery agents, such as porphyrin derivatives (< 1 nm), branched chain dendrimers (approximately 10 nm), polyethylenimine polymers (approximately 10 nm), nanoparticles (20-1,000 nm) and microspheres (> 1 microm), in the context of delivery to solid tumours. A discourse on how the chemical and physical properties of these carriers may affect the uptake of ONs into cells, particularly in-vivo, forms a major basis of this review.

Gene delivery with synthetic (non viral) carriers

Non-viral gene delivery involving the use of cationic polymer and cationic lipid based carriers still continues to enjoy a high profile due to the safety advantages offered by these systems when compared with viruses. However, there are still problems associated with the use of these agents, notably their comparatively low efficiency and the inability to target gene expression to the area of pathology. On intravenous administration gene expression is found predominantly in the first capillary bed encountered-the lung endothelium. The clinical use of non-viral gene delivery systems in cystic fibrosis or cancer has involved their direct application to the site of pathology due to the targeting difficulties experienced. For gene expression to occur genes must be transported to the interior of the cell nucleus and a number of biological barriers to effective gene delivery have been identified. These may be divided into extracellular such as the targeting barrier mentioned above and intracellular such as the need for endosomal escape after endocytosis and the inefficient trafficking of genes to the nucleus. Targeting ligands have been used with moderate success to overcome the targeting barrier while endosomal escape and nuclear targeting peptides are some of the strategies, which have been employed to overcome the problems of endosomal escape and nuclear trafficking. It is hoped that the next generation of carriers will incorporate mechanisms to overcome these barriers thus improving the efficacy of such materials.

Growth suppression of established human osteosarcoma lung metastases in mice by aerosol gene therapy with PEI-p53 complexes

Lung metastases are a frequent complication of osteosarcoma and a treatment that would reduce the severity of this complication would be of great benefit to patients. We have used a formulation consisting of polyethyleneimine (PEI) and a p53 gene administered in aerosol to treat established lung micrometastases as a model of human osteosarcoma in nude mice. The SAOS-LM6 cell line, a metastatic derivative of the p53 null SAOS-2 line, expresses high levels of p53 protein after in vitro transfection with PEI-p53 complexes as determined by ELISA, and transfection with both p53wt and the p53 variant, p53-CD(1-366) in vitro, results in a marked inhibition of SAOS-LM6 cell proliferation. Aerosol delivery of plasmid DNA containing either the p53 gene or a p53-CD(1-366) variant gene formulated with PEI to mice resulted in highly significant reductions in the numbers and size of tumors (P<.001), the total number of tumor foci in the lungs (P<.001) and the size of individual tumor nodules in treated animals compared to untreated, PEI only-treated and PEI-CAT-treated control animals. The different tissues examined did not reveal any signs of toxicity or inflammation after repeated exposure to PEI-DNA. The aerosol delivery of PEI-based formulations of p53 or synthetic p53 variant genes represents a promising new strategy for the treatment of established human osteosarcoma lung metastases. The noninvasive nature of aerosol delivery coupled with low toxicity also make this therapeutic approach potentially appropriate for combination therapy with either radio- or chemotherapy.