Current Pharmaceutical Biotechnology - Volume 15, Issue 9, 2014

Toll-like receptor 9 (TLR9) can sense pathogen DNA and CpG ODN or even self-DNA by trafficking assisted by Unc93B1, an endoplasmic reticulum (ER) transmembrane protein, from ER to endolysosomes or cell surface. In previous study, we found that an oligodeoxynucleotide with CCT repeats (SAT05f) could selectively inhibit TLR7/9 activation. However, the mechanism for the inhibitory activity of SAT05f is still unknown. In present research, it was found that SAT05f could inhibit CpG ODN-induced the intracellular trafficking of TLR9 and Unc93B1 with feedback the responses of decreased surface TLR9 and enhanced TLR9 mRNA expression but not influence TLR9 protein level by using human plasmacytoid dendritic cell line CAL-1 cells, suggesting that SAT05f inhibits TLR9 activation by restraining TLR9 trafficking. Since the mitochondrial DNA released from injured tissue can cause systemic inflammatory response syndrome (SIRS), this study may provide valuable data for prevention and treatment of SIRS and rescue severe trauma patients.

This study aimed to evaluate the co-delivery of cationic liposome/plasmid DNA complexes and cationic liposome/antisense oligodeoxyribonucleotide (AS ODN) complexes in HeLa human cervical carcinoma cells. Dimethyldioctadecyl ammonium bromide (DDAB): dioleoyl phosphatidylethanolamine (DOPE) liposome/plasmid DNA complexes, and DDAB:DOPE liposome/AS ODN complexes were formulated and characterized in terms of agarose gel electrophoretic mobility, particle size and zeta potential. The complexes were evaluated for delivery of pEGFP plasmid DNA and AS ODN in HeLa cells. Cell growth inhibition was evaluated using p53 plasmid DNA and bcl-2 AS ODN, by codelivery of DDAB:DOPE liposome/p53 plasmid DNA and DDAB:DOPE liposome/bcl-2 AS ODN complexes. The particle size of DDAB:DOPE liposome/plasmid DNA complexes, and DDAB:DOPE liposome/AS ODN complexes were 180.6±2.0 to 372.3±2.4 nm, and zeta potentials were -26.7±1.2 to +6.8±0.4 mV, respectively. The AS ODN uptake and green fluorescent protein (GFP) expression upon their co-delivery by DDAB:DOPE liposomes were both high. Treatment of the cells with the co-delivery of DDAB:DOPE liposome/p53 plasmid DNA complexes and DDAB:DOPE liposome/ bcl-2 AS ODN complexes inhibited cell growth to a greater degree than that with either DDAB:DOPE liposome/p53 plasmid DNA complexes or DDAB:DOPE liposome/bcl-2 AS ODN complexes alone. These data suggest that co-delivery of cationic liposome/p53 plasmid DNA and cationic liposome/bcl-2 AS ODN complexes is an effective strategy to achieve enhanced therapeutic activities.

Antisense oligonucleotides (ASOs) have promising therapeutic potential in oncotherapy. However, low stability and efficacy limit their application in the clinic. Cationic liposomes have been investigated as delivery vehicles for ASOs. Here, we report the synthesis and evaluation of an ASO delivery vehicle comprising cationic liposomes incorporating fatty acid-modified polyethylenimine. An oleic acid derivative of branched polyethylenimine (PEI-OA) and a linoleic acid derivative of branched polyethylenimine (PEI-LA) were synthesized and incorporated into liposomes. The PEImodified liposomes were synthesized by an ethanol injection method with composition of PEI-modified lipid/Chol/TPGS. The properties of these liposomes, including cytotoxicity, cellular uptake, ASO target silencing activity, based on mRNA and protein downregulation, were investigated. LOR-2501, an ASOs targeting ribonucleotide reductase R1 subunit (R1) was used as the therapeutic cargo. The PEI-modified liposomes showed relatively compact particle size and excellent colloidal stability for at least 25 days. PEI-modified liposomes effectively delivered LOR-2501 into KB cells and efficiently induced down-regulation of R1 mRNA and protein. Compared with regular cationic liposomes, PEI-modified liposomes was more effective, reducing R1 mRNA and protein by ~10%.

The development of nucleic acid-based drugs has attracted considerable interest in the past two decades as a new category of biologics. A key challenge in successfully achieving the full potential of nucleotide therapeutics is their efficient delivery. Synthetic cationic lipids are currently the most extensively used non-viral nucleotide carriers because of their ability to form complexes with the nucleic acids. Here we examine the properties of oligonucleotide lipoplexes with a particularly noteworthy cationic lipid class, the cationic phosphatidylcholines (PCs) which exhibit low toxicity and good nucleotide delivery efficacy. Studies on a set of cationic PCs reveal the existence of a strong, systematic dependence of their carrier efficiency on the lipid hydrocarbon chain structure. Their activity rises with the increase in chain unsaturation and declines with the increase in chain length. Maximum transfection is detected for ethyl-PC (ePC) with monounsaturated 14:1 chains. The same lipid exhibits maximum activity also in intracellular delivery of siRNA. As the lipid phase behavior is known to depend substantially on the hydrocarbon chain structure, the above relationships validate a view that cationic PC phase properties are an important factor for their activity. Indeed, time-resolved X-ray diffraction studies showed that the rate of the nucleotide release from the lipoplexes, as well as their transfection activity, correlate with the non-lamellar phase progressions detected in mixtures of cationic PCs with biomembrane lipids. These findings emphasize the role of the non-lamellar lipid mesophases in the nucleic acid transport across the cellular membranes and their intracellular release.

Membrane insertion peptides have been developed in recent years and serve as cargos to deliver small molecules into cells. A class of membrane insertion peptides is the so called pH-induced peptides (pHLIPs), which are able to insert into membrane when the environment pH is acidic. Despite a number of experimental studies, the insertion process as well as the penetration mechanism is still worth study with computational methods. Thus, we performed molecular dynamics simulations in this study to elucidate the detailed penetration process and mechanism. Both protonated and unprotonated peptides are employed to interact with a POPCs bilayer. By analyzing the trajectory of the simulation, the peptide travelling across membrane is expected to take milliseconds or seconds. While the peptide penetrating through the POPC bilayer boundary is much faster (several nanoseconds). More importantly, the elaborate energies between a peptide and water molecules, the energies between a peptide and POPCs have been analyzed throughout the simulation time correspondingly. A constant decrease of interaction energies have been observed for peptide-water interaction in the protonated condition. At last, we employ the statistics of hydrogen bonds to explain the penetration mechanism tentatively. For the protonated system, the decrease of hydrogen bonds of peptide-water and the increase of hydrogen bonds of peptide- POPCs have been considered as the main driven force for the peptide insertion.

Microfluidically (MF) synthesized lipid nanoparticles (LNPs) for antisense oligonucleotides (ODN) delivery have been shown to be superior to those prepared by bulk mixing (BM). In this study, a 5-inlet MF chip was used to synthesize LNPs loaded with LOR-2501, an antisense ODN targeting the ribonucleotide reductase R1 subunit. The size distribution of ODN- LNPs was measured by dynamic light scattering. The cytotoxicity of ODN- LNPs was determined by MTS assay. Gene silencing activity of ODN- LNPs was investigated by qRT-PCR and by Western blot. Results showed that MF synthesis produced ODN-LNPs that have lower average size and polydispersity values. The highest antisense activity was shown by LNs synthesized by the MF T2 chip, with downregulation of R1 mRNA by 32.5%. In conclusion, given their simplicity, affordability and reproducibility, MF is an attractive method for synthesis of LNs for ODN delivery.

Nanoparticles have shown great promise for improving the efficacy of nucleic acid drugs that lack permeability and bioavailability needed for reaching their intracellular site of action. The pharmacokinetics of the nucleic acid nanomedicines contributes greatly to their pharmacodynamic and toxicity characteristics. The pharmacokinetics of nanomedicines is determined by their physiochemical properties, such as particle size, shape, surface charge, and surface modifications. This review presented the pharmacokinetic and pharmacodynamic perspectives of nucleic acid nanomedicines. The cellular trafficking of the nucleic acid nanomedicines after cellular uptake is also discussed. In addition, the review puts forward potential strategies for circumventing biological barriers to delivering and releasing nucleic acid drugs into their intracellular site of action, and perspectives in this rapidly evolving field.

Objective: Among heterogeneous glioblastoma multiforme (GBM) cells, glioblastoma stem cells (GSCs) is a subpopulation having a critical role in tumor initiation and therapy resistance. Thus targeting GSCs would be an essential step to completely eradicate this lethal disease. MicroRNA-1 (miR-1) expression is deregulated in GBM patients and restoration of miR-1 by viral-vector in GBM cells has been demonstrated to inhibit tumor initiation and attenuate cell migration. Here, we show that a transferrin-targeting non-invasive nanoparticle delivery system (Tf-NP) can efficiently deliver miR-1 to GBM patient-derived GSC-enriched sphere cultures (GBM spheres). Methods: Delivery efficiency of the transferrin- targeting non-invasive nanoparticle was investigated by flow cytometry and further confirmed by confocal microscopy. The levels of miR-1 and its target molecules in GBM spheres were measured by qRT-PCR and immunoblotting. Migration capacity of Tf-NP-miR-1 treated GBM spheres were evaluated by transwell migration assay. Results: Tf-NPmiR- 1 treatment resulted in an over 200-fold increase of mature miR-1 compared to free miR-1 and Tf-NP-miR negative control (Tf-NP-miR-NC). Transferrin-mediated NP delivery resulted in a 3-fold higher delivery efficiency compared to NP without transferrin modification. Tf-NP-miR-1 treatment on GBM spheres significantly inhibited migration of GBM spheres by 30–50% with associated decline of MET and EGFR expression. Our data supported that Tf-NP could be used as an efficient and effective delivery system which has high potential to benefit the development of miR-based therapeutics for GBM treatment.

Antisense oligonucleotides (AS-ODNs) are short, single-stranded DNA molecules designed to bind specifically to a target messenger RNA (mRNA) and down-regulate gene expression. Despite being a promising class of therapeutics for a variety of diseases, they face major hurdles limiting their clinical application, including low intracellular delivery and poor in vivo stability. Among strategies available to enhance delivery, lipid nanoparticles have gained considerable attention. Active targeting of carriers of AS-ODNs is likely to further enhance delivery efficiency. For that, ligands for overexpressed receptors on the cell surface can be linked to the lipid nanoparticle, facilitating intracellular uptake, resulting in improved efficacy and reduced systemic toxicity. These include cell penetrating peptides (CPPs), transferrin, folate, oligosaccharides, polysaccharides and antibodies. Although targeted-lipid nanoparticles have been shown to enhance intracellular delivery and therapeutic effect of AS-ODNs, no clinical evaluation has been conducted yet. Therefore, more efforts are needed to turn these promising tools into clinical products.

Human brain natriuretic peptide (BNP) is utilized in the treatment of acute decompensated congestive heart failure. However, BNP has limited clinical use owing to its rapid clearance and the need for continuous intravenous infusion. Thus, we generated human serum albumin (HSA)-BNP fusion constructs to produce long-acting fusion proteins in Pichia pastoris. Four fusion proteins, BNP–HSA, (BNP)2–HSA, (BNP)4–HSA, and HSA–(BNP)2, were constructed, with different numbers of BNP molecules and fusion orientations. BNP–HSA was most abundantly expressed in Pichia pastoris and (BNP)4–HSA had the lowest yield, probably because of the high copy number of BNP. Western blot analysis confirmed the immunogenicity of both BNP and HSA for the four fusion proteins. A cGMP activity assay was used to measure the ability of fusion proteins to stimulate intracellular cGMP expression. Results showed that the fusion protein HSA–(BNP)2 activated human natriuretic peptide receptor A (hNPR-A) with potency similar to that of BNP, despite using a 10-fold higher dosage than BNP. The other three fusion proteins (BNP–HSA, (BNP)2–HSA, and (BNP)4–HSA), only slightly increased NPR-A activity. In addition, fusion with HSA successfully prolonged BNP bioactivity, stimulating intracellular cGMP expression over 24 h. In conclusion, HSA–(BNP)2, with two BNP molecules fused at the C-terminus of HSA, has the highest and most prolonged BNP bioactivity in activating human NPR-A.

Recent advances in nanotechnology and nanobiotechnology have contributed to the development of nanomaterials, able to be used as drug carriers, probes, targets or cytostatic drugs by itself. Nanomedicine is now the leading area in nanotechnology where a large number and types of nanoparticles (NPs) has been developed and several are already in the clinical practice. Chemotherapy is one of the most widely used strategies to treat cancer. Most chemotherapeutic agents have poor solubility, low bioavailability, and are formulated with toxic solvents. NPs have been designed to overcome the lack of specificity of chemotherapeutic agents as well to improve circulation time in blood, taking advantages on tumor cells characteristics. In immunology, recent advances regarding the activation of the innate immune system artificially enhanced by NPs functionalized with immune-stimulators open a new window as novel methods in vaccines. Also, viruses and virus-like particles (VLPs) engineered to stimulate immune response against their similar virus or as molecular platforms for the presentation of foreign epitopes have been described. In this review we focused in the use of different types of NPs in oncology and immunology, pinpointing the main novelties regarding their development and use of nanotechnology in a broad array of applications, ranging from tumor diagnostics, immune-modulation up to cancer therapeutics.

Demonstrating comparability of secondary structure composition as part of higher order structure (HOS) in therapeutic proteins is a significant challenge. Previously, we showed that the variability of second derivative amide I Fourier transform infrared (FTIR) spectra were small enough that significant differences in secondary structures could be seen for a variety of model proteins. Those comparisons used spectral overlap and spectral correlation coefficients to quantify spectral differences. However, many of the excipients used in downstream purification process, drug substance, and drug product formulation, such as free amino acids and sugars, can interfere with the absorbance in the amide I region. In this study, analysis of amide II FTIR spectra is shown as an alternative to using spectral data from the amide I region to analyze protein secondary structure to assess their HOS. This research provided spectral overlap and spectral correlation coefficient mathematical approaches for analysis of amide II FTIR spectra to demonstrate comparability of protein secondary structure. Spectral overlap and spectral correlation coefficients results show strong correlations between changes in the second derivative of amide II and amide I FTIR spectra for various model proteins under different conditions, which demonstrate the applicability of using amide II FTIR spectra for the comparability of protein secondary structure. These results indicate that the analysis of the second derivative of amide II FTIR spectra may be used to monitor and demonstrate comparability of protein secondary structure during downstream process and formulation development of protein therapeutics.