Validation of a Novel Collection Device for Non-Invasive Urine Sampling from Free-Ranging Animals

Recent advances in non-invasively collected samples have opened up new and exciting opportunities for wildlife research. Different types of samples, however, involve different limitations and certain physiological markers (e.g., C-peptide, oxytocin) can only be reliably measured from urine. Common collection methods for urine to date work best for arboreal animals and large volumes of urine. Sufficient recovery of urine is thus still difficult for wildlife biologists, particularly for terrestrial and small bodied animals. We tested three collection devices (two commercially available saliva swabs, Salivette synthetic and cotton, and cotton First aid swabs) against a control to permit the collection of small volumes of urine from the ground. We collected urine samples from captive and wild macaques, and humans, measured volume recovery, and analyzed concentrates of selected physiological markers (creatinine, C-peptide, and neopterin). The Salivette synthetic device was superior to the two alternative devices. Concentrations of creatinine, absolute C-peptide, C-peptide per creatinine, absolute neopterin, and neopterin per creatinine measured in samples collected with this device did not differ significantly from the control and were also strongly correlated to it. Fluid recovery was also best for this device. The least suitable device is the First aid collection device; we found that while absolute C-peptide and C-peptide per creatinine concentrations did not differ significantly from the control, creatinine concentrations were significantly lower than the control. In addition, these concentrations were either not or weakly correlated to the control. The Salivette cotton device provided intermediate results, although these concentrations were strongly correlated to the control. Salivette synthetic swabs seem to be useful devices for the collection of small amounts of urine from the ground destined for the assessment of physiological parameters. They thus provide new opportunities for field studies to incorporate physiological markers, particularly on smaller bodied and terrestrial animals and where urine collection is difficult.     

Making Contact: Rooting Out the Potential for Exposure of Commercial Production Swine Facilities to Feral Swine in North Carolina

Despite North Carolina’s long history with feral swine, populations were low or absent in eastern counties until the 1990s. Feral swine populations have since grown in these counties which also contain a high density of commercial production swine (CPS) facilities. Sixteen of the highest swine producing U.S. counties also populated with feral swine are in North Carolina. Disconcertingly, since 2009, positive tests for exposure to swine brucellosis or pseudorabies virus have been found for feral swine. We surveyed 120 CSP facilities across four eastern counties to document the level and perception of feral swine activity around CSP facilities and to identify disease transmission potential to commercial stock. Nearly all facility operators (97%) recognized feral swine were in their counties. Far fewer said they had feral swine activity nearby (18%). Our inspections found higher presence than perceived with feral swine sign at 19% of facilities where operators said they had never observed feral swine or their sign. Nearly 90% expressed concern about feral to domestic disease transmission, yet only two facilities had grain bins or feeders fenced against wildlife access. Due to increasing feral swine populations, recent evidence of disease in feral populations, the importance of swine production to North Carolina’s economy and the national pork industry, and potential for feral-domestic contact, we believe feral swine pose an increasing disease transmission threat warranting a stringent look at biosecurity and feral swine management at North Carolina CPS facilities.     

Novel Delivery Systems for Interferons

ABSTRACT

Interferons, IFNs, are among the most widely studied and clinically used biopharmaceuticals. Despite their invaluable therapeutic roles, the widespread use of IFNs suffers from some inherent limitations, mainly their relatively short circulation lifespan and their unwanted effects on some non-target tissues. Therefore, both these constraints have become the central focus points for the research efforts on the development of a variety of novel delivery systems for these therapeutic agents with the ultimate goal of improving their therapeutic end-points. Generally, the delivery systems currently under investigation for IFNs can be classified as particulate delivery systems, including micro- and nano-particles, liposomes, minipellets, cellular carriers, and non-particulate delivery systems, including PEGylated IFNs, other chemically conjugated IFNs, immunoconjugated IFNs, and genetically conjugated IFNs. All these strategies and techniques have their own possibilities and limitations, which should be taken into account when considering their clinical application. In this article, currently studied delivery systems/techniques for IFN delivery have been reviewed extensively, with the main focus on the pharmacokinetic consequences of each procedure.     

Novel Acoustic Technology for Studying Free-Ranging Shark Social Behaviour by Recording Individuals' Interactions

Group behaviours are widespread among fish but comparatively little is known about the interactions between free-ranging individuals and how these might change across different spatio-temporal scales. This is largely due to the difficulty of observing wild fish groups directly underwater over long enough time periods to quantify group structure and individual associations. Here we describe the use of a novel technology, an animal-borne acoustic proximity receiver that records close-spatial associations between free-ranging fish by detection of acoustic signals emitted from transmitters on other individuals. Validation trials, held within enclosures in the natural environment, on juvenile lemon sharks Negaprion brevirostris fitted with external receivers and transmitters, showed receivers logged interactions between individuals regularly when sharks were within 4 m (∼4 body lengths) of each other, but rarely when at 10 m distance. A field trial lasting 17 days with 5 juvenile lemon sharks implanted with proximity receivers showed one receiver successfully recorded association data, demonstrating this shark associated with 9 other juvenile lemon sharks on 128 occasions. This study describes the use of acoustic underwater proximity receivers to quantify interactions among wild sharks, setting the scene for new advances in understanding the social behaviours of marine animals.     

A Novel Aminopeptidase with Highest Preference for Lysine

Neuropeptides are formed from sedentary precursors to smaller, active peptides by processing enzymes cleaving at paired basic residues. The process generates peptide intermediates with additional Lys or Arg residues at their NH(2) and COOH termini; the N-terminal basic amino acids are later removed by specific aminopeptidases. We report here a novel lysine-specific aminopeptidase (KAP) of ubiquitous distribution. The enzyme was resolved from puromycin-sensitive aminopeptidase (PSA), aminopeptidase B (APB), and neuron-specific aminopeptidase (NAP). It was purified by FPLC after (NH(4))(2)SO(4) precipitation. The purified KAP had a K(m) of 333 microM with a V(max) of 0.7 nmol Lys ssNA/min/mg protein. N-terminal basic amino acids, Lys in particular, were its favorable substrates. KAP was inhibited by chelating agents and by serine protease inhibitors. It was highly sensitive to aminopeptidase inhibitor bestatin, but insensitive to puromycin and amastatin, showing that KAP is distinct from PSA, NAP, and aminopeptidase A (APA). The 62,000-Da enzyme had a pH optimum at 7.5 and NaCl was its strongest activator. However, metals could not restore KAP's activity after it was dialyzed against EGTA. Our data indicated that rat KAP did not resemble any aminopeptidases as well as the microbial lysine aminopeptidases.     

Fat-free Albumin as a Novel Drug Delivery System

The search for effective drug delivery systems is one of the major challenges in drug formulation especially for biopharmaceuticals such as proteins, and peptide-based drugs and vaccines. A procedure has been developed whereby human serum albumin (HSA) can be used as a delivery vehicle for these biomolecules using its role as main fatty acid carrier. Using essentially fatty acid free HSA (HSAff) it is possible to form stable complexes with lipidic chain compounds (lipo-compounds). Two lipo-compounds have been used to develop this system, a novel antimicrobial lipopeptide and γ-amino-n-butyric acid, GABA, conjugated with an alkyl chain, lipo-GABA, in both cases C8 and C14 alkyl chain lengths were evaluated. The HAS–lipo compound complex had a mutual stabilizing effect on both the HSA and the lipo-compound. The protease enzyme study showed that the alkyl chains of these lipo-compounds bound to HSAff confer a similar if not greater biostability than caprylic acid shown by CD and importantly, the bound lipopeptide was stabilized by the HSA shown by mass spectrometry. Heat stability studies at 60°C over 10 h also confirmed that the lipo-HSA complexes confer stability and provide a method of preparing sterile formulation for therapeutic use. No further increased in stability of the lipo-compounds when HSA containing fatty acid (HSAfa) was used. With the antimicrobial lipopeptide, there was enhanced activity with HSAff formulation suggesting increased biostability and bioavailability of compounds. These finding allowed us to develop a simple and effective way of delivering lipo-compounds using fatty acid free HSA as the carrier.Australian Peptide Conference Issue.     

A Novel Nanoparticle Formulation for Sustained Paclitaxel Delivery

Purpose  To develop a novel nanoparticle drug delivery system consisting of chitosan and glyceryl monooleate (GMO) for the delivery of a wide variety of therapeutics including paclitaxel. Methods  Chitosan/GMO nanoparticles were prepared by multiple emulsion (o/w/o) solvent evaporation methods. Particle size and surface charge were determined. The morphological characteristics and cellular adhesion were evaluated with surface or transmission electron microscopy methods. The drug loading, encapsulation efficiency, in vitro release and cellular uptake were determined using HPLC methods. The safety and efficacy were evaluated by MTT cytotoxicity assay in human breast cancer cells (MDA-MB-231). Results  These studies provide conceptual proof that chitosan/GMO can form polycationic nano-sized particles (400 to 700 nm). The formulation demonstrates high yields (98 to 100%) and similar entrapment efficiencies. The lyophilized powder can be stored and easily be resuspended in an aqueous matrix. The nanoparticles have a hydrophobic inner-core with a hydrophilic coating that exhibits a significant positive charge and sustained release characteristics. This novel nanoparticle formulation shows evidence of mucoadhesive properties; a fourfold increased cellular uptake and a 1000-fold reduction in the IC₅₀ of PTX. Conclusion  These advantages allow lower doses of PTX to achieve a therapeutic effect, thus presumably minimizing the adverse side effects.     

Neural Stem Cells as a Novel Platform for Tumor-Specific Delivery of Therapeutic Antibodies

Background

Recombinant monoclonal antibodies have emerged as important tools for cancer therapy. Despite the promise shown by antibody-based therapies, the large molecular size of antibodies limits their ability to efficiently penetrate solid tumors and precludes efficient crossing of the blood-brain-barrier into the central nervous system (CNS). Consequently, poorly vascularized solid tumors and CNS metastases cannot be effectively treated by intravenously-injected antibodies. The inherent tumor-tropic properties of human neural stem cells (NSCs) can potentially be harnessed to overcome these obstacles and significantly improve cancer immunotherapy. Intravenously-delivered NSCs preferentially migrate to primary and metastatic tumor sites within and outside the CNS. Therefore, we hypothesized that NSCs could serve as an ideal cellular delivery platform for targeting antibodies to malignant tumors.

Methods and Findings

As proof-of-concept, we selected Herceptin™ (trastuzumab), a monoclonal antibody widely used to treat HER2-overexpressing breast cancer. HER2 overexpression in breast cancer is highly correlated with CNS metastases, which are inaccessible to trastuzumab therapy. Therefore, NSC-mediated delivery of trastuzumab may improve its therapeutic efficacy. Here we report, for the first time, that human NSCs can be genetically modified to secrete anti-HER2 immunoglobulin molecules. These NSC-secreted antibodies assemble properly, possess tumor cell-binding affinity and specificity, and can effectively inhibit the proliferation of HER2-overexpressing breast cancer cells in vitro. We also demonstrate that immunoglobulin-secreting NSCs exhibit preferential tropism to tumor cells in vivo, and can deliver antibodies to human breast cancer xenografts in mice.

Conclusions

Taken together, these results suggest that NSCs modified to secrete HER2-targeting antibodies constitute a promising novel platform for targeted cancer immunotherapy. Specifically, this NSC-mediated antibody delivery system has the potential to significantly improve clinical outcome for patients with HER2-overexpressing breast cancer.     

Novel Jojoba Oil-Based Emulsion Gel Formulations for Clotrimazole Delivery

Jojoba oil-based emulgel formulations were prepared using different concentrations of various gelling agents, such as hydroxypropyl methylcellulose (HPMC) and Carbopol 934 P and combination of both. The prepared emulgels were physically evaluated for their stability after temperature cycle test, centrifugation and long-term shelf storage for 1 year at room temperature. The in vitro release at 37°C was studied to define the effect of the concentration and type of the gelling agent. A comparison between the formulated emulgels and two commercially available products, Candistan® and Canesten® creams, was carried out to judge their efficacy and stability. The prepared emulgels exhibited non-Newtonian shear thinning behavior with little or no thixotropy. Four emulgels showed excellent stability as they demonstrated consistent rheological model under different treatment conditions. The in vitro release test showed variation in the extent of percent drug released. The drug release from the commercial preparation was lower than some of the prepared emulgel formulae. One formula containing combination of the two gelling agents (HPMC and Carbopol 934 P), showed excellent stability and high extent of clotrimazole release was microbiologically evaluated against Candida albicans using cylinder and plate method. The selected formula showed superior antimycotic activity compared to the commercially available formulation. Further in vivo animal studies for the obtained stable formula is recommended.     

Development and Evaluation of a Novel Delivery System Containing Phytophospholipid Complex for Skin Aging

Citrus auranticum and Glycyrrhiza glabra are rich in anti-oxidant polyphenols helpful in prevention of skin aging. Polyphenols have high polarity and lower skin penetration resulting in lower cutaneous delivery. The present work is attempted to develop a novel polyherbal phospholipid complex cream to improve cutaneous delivery of polyphenols for sustained anti-oxidant action. Phytochemical and in vitro anti-oxidant evaluation was done on methanolic extracts of orange peel and liquorice powder. Total phenolic content, total flavonoid content, and anti-oxidant assays were done on different ratios of orange peel and liquorice extract. Ratio 1:2 gave highest total phenolic content (TPC) (530.00?±?1.56 mg gallic acid equivalent (GAE)?g^?1 extract), total flavonoid content (TFC) (246.25?±?1.03 mg rutin equivalent (RUE)?g^?1 extract), 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity (87.99?±?0.64%), and H₂O₂ scavenging activity (72.47?±?0.86%) and hence was used for formulation. Solvent evaporation method using methanol with 1:1 extract to phospholipid ratio was found to have entrapment efficiency of 93.22?±?0.26%. Evaluation parameters like scanning electron microscopy (SEM), Fourier transform infrared spectrophotometry (FT-IR), and differential scanning calorimetry (DSC) confirmed formation of complex. The complex was formulated as oil-in-water cream and evaluated for various parameters. The optimized cream containing 1% complex was non-irritant and was found to be stable for 3-month period under conditions of stability study. Ex vivo diffusion studies showed that extract phospholipid complex cream had better retention of polyphenols in the skin when compared to conventional extract cream giving prolonged and stronger topical action. The cream had an anti-elastase activity of 28.02?±?0.95% at concentration of 3000 μg ml^?1 (w/v). Thus, the developed safe and stable polyherbal phytophospholipid complex cream exhibited good potential as anti-aging cosmeceutical.     

Targeted Delivery of Antisense Oligodeoxynucleotides Formulated in a Novel Lipidic Vector

Abstract

A novel lipidic system has been developed to selectively deliver oligo-deoxynucleotides (ODN) to target cells. It involves the complexation of ODN with polylysine, followed by the addition of pH-sensitive liposomes that contain a targeting ligand, folate. The resulting particles, named LPDII, efficiently and selectively deliver ODN to human KB cells which overexpress folate-binding proteins (FBP). When an ODN against epidermal growth factor receptors (EGFR) was formulated in LPDII, delivery of these particles to KB cells resulted in down-regulation of EGFR and also cell growth inhibition. Free ODN exhibited no inhibitory effect on the growth of KB cells in the same concentration range. An ODN of scrambled sequence, free or formulated in LPDII, also failed to inhibit the growth of KB cells. Finally, the antisense effect of ODN on KB cells was inhibited by an excess amount of free folate, suggesting that the sequence-dependent effect of the ODN was mediated by folate binding protein.     

穿膜肽介导的新型基因转运载体的功能研究

目的：借助穿膜肽TAT高效跨膜的特性和LacI前头肽突变体（LacI HPM）高亲和力结合DNA的特性,建立-种安全高效、无基因插入片段大小限制的基因转导系统。方法：在TAT-LacI HPM片段C端和N端分别添加GST标签,构建pET-28a（＋）-TAT-LacI HPM-GST和pGEX-GST-TAT-LacI HPM重组表达载体,可溶性表达TAT-LacI HPM-GST及GST-TAT-LacI HPM融合蛋白并纯化,获得TAT-LacI HPM二聚体,免疫荧光检测TAT-LacI HPM融合蛋白穿过HeLa细胞膜的情况,观察EGFP的表达,用免疫印迹检测TAT-LacI HPM融合蛋白介导质粒DNA进入细胞的能力。结果：表达、纯化并获得二聚体融合蛋白,体内实验表明其具有跨膜能力,能介导带有LacI结合序列的DNA质粒进入细胞,并在转染细胞里检测到了目的蛋白。结论：初步证实TAT-LacI HPM融合蛋白作为-种新型通用性非病毒DNA转运载体的可行性,为评价这种新型DNA疫苗载体在提高免疫效果方面的可行性奠定了前期实验基础。     

Novel inhibition of porcine pepsin by a substituted piperidine. Preference for one of the enzyme conformers

Pepsin inhibition by 3-alkoxy-4-arylpiperidine (substituted piperidine; (3R,4R)-3-(4-bromobenzyloxy)-4-[4-(2-naphthalen-1-yl-2-oxo-ethoxy)phenyl]piperidine) has been studied using steady-state kinetic and pre-equilibrium binding methods. Data were compared with pepstatin A, a well known competitive inhibitor of pepsin. Steady-state analysis reveals that the substituted piperidine likewise behaves as a competitive inhibitor. Pre-equilibrium binding studies indicate that the substituted piperidine can displace a fluorescently labeled statine inhibitor from the enzyme active site. Simulation of the stopped-flow fluorescence transients provided estimates of the K(d) values of 1.4 +/- 0.2 microm and 39 +/- 2 nm for the piperidine and the fluorescently labeled statine, respectively. The effects of combinations of these two inhibitors resulted in a series of parallel lines when plotted by the method of Yonetani and Theorell (Yonetani, T., and Theorell, H. (1964) Arch. Biochem. Biophys. 106, 234-251), suggesting that the two inhibitors bind in a mutually exclusive fashion to pepsin. Fitting of the entire data set to the appropriate equation yielded an alpha factor of 8 +/- 1. The magnitude of this factor ( infinity > alpha > 1) can be explained by a conformational distinction between the enzyme species that bind each inhibitor. The effects of pH on the inhibition constants for pepstatin A and the substituted piperidine also suggest that the inhibitors bind to distinct conformational forms of the enzyme. No inhibition by the piperidine was observed at acidic pH, while pepstatin A inhibition is maximal at low pH values. Inhibition by the piperidine was maximal when a group with pK 4.8 +/- 0.2 was deprotonated and another group with pK 5.9 +/- 0.2 was protonated. Most likely these two groups are the catalytic aspartates with perturbed ionization properties as a result of a significant and unique conformational change. Taken together, these data suggest that the enzyme can readily interconvert between two conformers, one capable of binding substrate and pepstatin A and the other capable of binding the substituted piperidine.     

Novel Drug Delivery System for Age-related Macular Degeneration Using Nanotechnology

Age-related macular degeneration (AMD) is a leading cause of legal blindness in developed countries. Even with the recent advent of several treatment options such as photodynamic therapy (PDT) and anti-vascular endothelial growth factor (VEGF) therapy for the treatment of exudative AMD, characterized by choroidal neovascularization (CNV), their efficacy is still limited. Thus, in this review article, we investigated novel drug delivery system for AMD using nanotechnology. Polyion complex (PIC) micelle has a size range of several tens of nanometers formed through electrostatic interaction, and accumulates in solid tumors through enhanced permeability and retention (EPR) effect. The distribution of the PIC micelle encapsulating fluorescein isothiocyanate-labeled poly-l-lysine (FITC-P(Lys)) in experimental CNV in rats was investigated. PIC micelle accumulates in the CNV lesions and is retained in the lesion for as long as 168 h after intravenous administration. PIC micelles can be used for achieving effective drug delivery system to CNV. Although PDT is a main treatment option for CNV, most patients require repeated treatments. For effective PDT against AMD, the selective delivery of photosensitizer to the CNV lesions and an effective photochemical reaction at the CNV site are necessary. The characteristic dendritic structure of the photosensitizer prevents aggregation of its core sensitizer, thereby inducing a highly effective photochemical reaction. A supramolecular nanomedical device, i.e., a novel dendritic photosensitizer encapsulated by a polymeric micelle formulation was employed for an effective PDT for AMD. With its highly selective accumulation on CNV lesions, this treatment resulted in a remarkably efficacious CNV occlusion with minimal unfavorable phototoxicity. Our results will provide a basis for an effective approach to PDT for AMD.     

Novel Vitamin and Gold-Loaded Nanofiber Facial Mask for Topical Delivery

l-ascorbic acid has been widely used in cosmetic and dermatological products because of its ability to scavenge free radicals and destroy oxidizing agents. However, it is chemically unstable and can easily be oxidized. The current cosmetic facial masks available in the market are pre-moistened, which means that the aqueous fluid content of the mask may oxidize some of the unstable active ingredients such as ascorbic acid. This work presents an anti-wrinkle nanofiber face mask containing ascorbic acid, retinoic acid, gold nanoparticles, and collagen. This novel face mask will only be wetted when applied to the skin, thus enhancing product stability. Once moistened, the content of the mask will gradually dissolve and release the active ingredients and ensure maximum skin penetration. The high surface area-to-volume ratio of the nanofiber mask will ensure maximum contact with the skin surface and help to enhance the skin permeation to restore its healthy appearance. Electrospun fiber mats may provide an attractive alternative to the commercial facial cotton masks.     

Design and Evaluation of Novel Solid Self-Nanodispersion Delivery System for Andrographolide

Poorly water-soluble drugs offer challenges in developing a formulation product with adequate bioavailability. This study took advantage of the features of nanocrystals and direct compression technologies to develop a novel solid self-nanodispersion delivery system for andrographolide (Andro) in order to increase its dissolution rate for enhancing bioavailability. Andro nanosuspensions (Andro-NS) with a particle size of about 500 nm were prepared by homogenization technology and further converted into dried nanocrystal particles (Andro-NP) via spray-drying. The solid self-nanodispersion delivery system (Andro-SNDS)-loaded Andro-NP was prepared via direct compression technology. The DSC and PXRD results demonstrated that the Andro nanocrystals retained its original crystallinity. The dissolution of the Andro-SNDS formulation was 85.87% in pure water over 30 min, better than those of the coarse Andro and physical mixture of Andro and stabilizer. And the C _max (299.32?±?78.54 ng/mL) and AUC_0-∞ (4440.55?±?764.13 mg/L?·?h) of the Andro-SNDS formulation were significantly higher (p?<?0.05) than those of the crude Andro (77.52?±?31.73 ng/mL and 1437.79?±?354.25 mg/L?·?h). The AUC of the Andro-SNDS was 3.09 times as high as that of the crude Andro. This study illustrated a novel approach to combine the features of nanocrystals and composite particles used to improve oral bioavailability of poorly soluble drug.     

Interactive Drivers of Activity in a Free-Ranging Estuarine Predator

Animal activity patterns evolve as an optimal balance between energy use, energy acquisition, and predation risk, so understanding how animals partition activity relative to extrinsic environmental fluctuations is central to understanding their ecology, biology and physiology. Here we use accelerometry to examine the degree to which activity patterns of an estuarine teleost predator are driven by a series of rhythmic and arrhythmic environmental fluctuations. We implanted free-ranging bream Acanthopagrus australis with acoustic transmitters that measured bi-axial acceleration and pressure (depth), and simultaneously monitored a series of environmental variables (photosynthetically active radiation, tidal height, temperature, turbidity, and lunar phase) for a period of approximately four months. Linear modeling showed an interaction between fish activity, light level and tidal height; with activity rates also negatively correlated with fish depth. These patterns highlight the relatively-complex trade-offs that are required to persist in highly variable environments. This study demonstrates how novel acoustic sensor tags can reveal interactive links between environmental cycles and animal behavior.     

Novel Therapeutic Approaches for Various Cancer Types Using a Modified Sleeping Beauty-Based Gene Delivery System

Successful gene therapy largely depends on the selective introduction of therapeutic genes into the appropriate target cancer cells. One of the most effective and promising approaches for targeting tumor tissue during gene delivery is the use of viral vectors, which allow for high efficiency gene delivery. However, the use of viral vectors is not without risks and safety concerns, such as toxicities, a host immune response towards the viral antigens or potential viral recombination into the host''s chromosome; these risks limit the clinical application of viral vectors. The Sleeping Beauty (SB) transposon-based system is an attractive, non-viral alternative to viral delivery systems. SB may be less immunogenic than the viral vector system due to its lack of viral sequences. The SB-based gene delivery system can stably integrate into the host cell genome to produce the therapeutic gene product over the lifetime of a cell. However, when compared to viral vectors, the non-viral SB-based gene delivery system still has limited therapeutic efficacy due to the lack of long-lasting gene expression potential and tumor cell specific gene transfer ability. These limitations could be overcome by modifying the SB system through the introduction of the hTERT promoter and the SV40 enhancer. In this study, a modified SB delivery system, under control of the hTERT promoter in conjunction with the SV40 enhancer, was able to successfully transfer the suicide gene (HSV-TK) into multiple types of cancer cells. The modified SB transfected cancer cells exhibited a significantly increased cancer cell specific death rate. These data suggest that our modified SB-based gene delivery system can be used as a safe and efficient tool for cancer cell specific therapeutic gene transfer and stable long-term expression.