PLGA-based gene delivering nanoparticle enhance suppression effect of miRNA in HePG2 cells

Interaction of autophagy with microRNAs and their potential therapeutic implications in human cancers

Autophagy is a tightly regulated intracellular self-digestive process involving the lysosomal degradation of cytoplasmic organelles and proteins. A number of studies have shown that autophagy is dysregulated in cancer initiation and progression, or cancer cells under various stress conditions. As a catabolic pathway conserved among eukaryotes, autophagy is regulated by the autophagy related genes and pathways. MicroRNAs (miRNAs) are small, non-coding endogenous RNAs that may regulate almost every cellular process including autophagy. And autophagy is also involved in the regulation of miRNAs expression and homeostasis. Here we reviewed some literatures on the interaction of miRNAs with autophagy and the application of miRNAs-mediated autophagic networks as a promising target in pre-clinical cancer models. Furthermore, strategies of miRNAs delivery for miRNAs-based anti-cancer therapy will also be summarized and discussed.

MicroRNAs associated with HBV infection and HBV-related HCC

Hepatitis B virus (HBV) infection is a global problem and a major risk factor for hepatocellular carcinoma (HCC). microRNAs (miRNAs) comprise a group of small noncoding RNAs regulating gene expression at the posttranslational level, thereby participating in fundamental biological processes, including cell proliferation, differentiation, and apoptosis. In this review, we summarize the roles of miRNAs in HBV infection, the recently identified mechanism underlying dysregulation of miRNAs in HBV-associated HCC, and their association with hepatocarcinogenesis. Moreover, we discuss the recent advances in the use of circulating miRNAs in the early diagnosis of HCC as well as therapies based on these aberrantly expressed miRNAs.

Nanoparticles carrying neurotrophin-3-modified Schwann cells promote repair of sciatic nerve defects

Schwann cells and neurotrophin-3 play an important role in neural regeneration, but the secretion of neurotrophin-3 from Schwann cells is limited, and exogenous neurotrophin-3 is inactived easily in vivo. In this study, we have transfected neurotrophin-3 into Schwann cells cultured in vitro using nanoparticle liposomes. Results showed that neurotrophin-3 was successfully transfected into Schwann cells, where it was expressed effectively and steadily. A composite of Schwann cells transfected with neurotrophin-3 and poly(lactic-co-glycolic acid) biodegradable conduits was transplanted into rats to repair 10-mm sciatic nerve defects. Transplantation of the composite scaffold could restore the myoelectricity and wave amplitude of the sciatic nerve by electrophysiological examination, promote nerve axonal and myelin regeneration, and delay apoptosis of spinal motor neurons. Experimental findings indicate that neurotrophin-3 transfected Schwann cells combined with bridge grafting can promote neural regeneration and functional recovery after nerve injury.

Enhanced cytotoxicity and apoptosis-induced anticancer effect of silibinin-loaded nanoparticles in oral carcinoma (KB) cells

Silibinin (SIL) is a plant derived flavonoid isolated from the fruits and seeds of the milk thistle (Silybum marianum). Silibinin possesses a wide variety of biological applications including anticancer activities but poor aqueous solubility and poor bioavailability limit its potential and efficacy at the tumor sites. In the present study, silibinin was encapsulated in Eudragit® E (EE) nanoparticles in the presence of stabilizing agent polyvinyl alcohol (PVA) and its anticancer efficacy in oral carcinoma (KB) cells was studied. Silibinin loaded nanoparticles (SILNPs) were prepared by nanoprecipitation technique and characterized in terms of size distribution, morphology, surface charge, encapsulation efficiency and in vitro drug release. MTT assay revealed higher cytotoxic efficacy of SILNPs than free SIL in KB cells. Meanwhile, reactive oxygen species (ROS) determination revealed the significantly higher intracellular ROS levels in SILNPs treated cells compared to free SIL treated cells. Therefore, the differential cytotoxicity between SILNPs and SIL may be mediated by the discrepancy of intracellular ROS levels. Moreover, acridine orange (AO) and ethidium bromide (EB) dual staining and reduced mitochondrial membrane potential (MMP) confirmed the induction of apoptosis with nanoparticle treatment. Further, the extent of DNA damage (evaluated by comet assay) was significantly increased in SILNPs than free SIL in KB cells. Taken together, the present study suggests that silibinin-loaded nanoparticles can be used as an effective drug delivery system to produce a better chemopreventive response for the treatment of cancer.

A sight on the current nanoparticle-based gene delivery vectors

Nowadays, gene delivery for therapeutic objects is considered one of the most promising strategies to cure both the genetic and acquired diseases of human. The design of efficient gene delivery vectors possessing the high transfection efficiencies and low cytotoxicity is considered the major challenge for delivering a target gene to specific tissues or cells. On this base, the investigations on non-viral gene vectors with the ability to overcome physiological barriers are increasing. Among the non-viral vectors, nanoparticles showed remarkable properties regarding gene delivery such as the ability to target the specific tissue or cells, protect target gene against nuclease degradation, improve DNA stability, and increase the transformation efficiency or safety. This review attempts to represent a current nanoparticle based on its lipid, polymer, hybrid, and inorganic properties. Among them, hybrids, as efficient vectors, are utilized in gene delivery in terms of materials (synthetic or natural), design, and in vitro/in vivo transformation efficiency.

Physicochemical features and transfection properties of chitosan/poloxamer 188/poly(D,L-lactide-co-glycolide) nanoplexes

The aim of this study was the evaluation of the effects of two emulsifiers on the physicochemical and technological properties of low molecular weight chitosan/poly (D,L-lactide-co-glycolide) (PLGA) nanoplexes and their transfection efficiency. Nanospheres were prepared using the nanoprecipitation method of the preformed polymer. The mean diameter and surface charge of the nanospheres were investigated by photocorrelation spectroscopy. The degree of binding of the plasmid with the nanoplexes was qualitatively and quantitatively determined. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) testing was performed using HeLa, RPMI8226, and SKMM1 cell lines. Flow cytometry and confocal laser scanning microscopy were used to determine the degree of cellular transfection and internalization of the nanoplexes into cells, respectively. The nanoplexes had a positive zeta potential, and low amounts of PLGA and poloxamer 188 showed a mean colloidal size of ~200 nm with a polydispersity index of ~0.14. The nanoplexes had suitable entrapment efficiency (80%). In vitro experiments showed that the colloidal nanodevices did not induce significant cytotoxicity. The nanoplexes investigated in this study could represent efficient and useful nonviral devices for gene delivery. Use of low amounts of PLGA and poloxamer 188 enabled development of a nanosphere able to transfect cells efficiently. These nanosystems are a helpful platform for delivery of genetic material while preserving therapeutic efficacy.

Aerosol-based fabrication of modified chitosans and their application for gene transfection

Modified chitosan nanoparticles were conveniently obtained by a one-step aerosol method, and their potential for gene transfection was investigated. Droplets containing modified chitosans were formed by collison atomization, dried to form solid particles, and collected and studied for potential use as nanocarriers. Modified chitosans consisted of a chitosan backbone and an additional component [covalently attached cholesterol; or blends with poly(l-lysine) (PLL), polyethyleneimine (PEI), or poly(ethylene glycol) (PEG)]. Agarose gel retardation assays confirmed that modified chitosans could associate with plasmid DNA. Even though the average cell viability of cholesterol-chitosan (Ch-Cs) showed a slightly higher cytotoxicity (∼90% viability) than that for unmodified chitosan (Cs, ∼95%), transfection (>7.5 × 10(5) in relative light units (RLU) mg(-1)) was more effective than it was for Cs (∼7.6 × 10(4) RLU mg(-1)). The blending of PEI with Cs (i.e., a Cs/PEI) to produce transfection complexes enhanced the transfection efficiency (∼1.3 × 10(6) RLU mg(-1)) more than did the addition of PLL (i.e., a Cs/PLL, ∼9.3 × 10(5) RLU mg(-1)); however, it also resulted in higher cytotoxicity (∼86% viability for Cs/PEI vs ∼94% for Cs/PLL). The average cell viability (∼92%) and transfection efficiency (∼1.9 × 10(6) RLU mg(-1)) were complemented further by addition of PEG in Cs/PEI complexes (i.e., a Cs/PEI-PEG). This work concludes that gene transfection of Cs can be significantly enhanced by adding cationic polymers during aerosol fabrication without wet chemical modification processes of Cs.

Polymer nanoparticles for drug and small silencing RNA delivery to treat cancers of different phenotypes

Advances in nanotechnology have provided powerful and efficient tools in the development of cancer diagnosis and therapy. There are numerous nanocarriers that are currently approved for clinical use in cancer therapy. In recent years, biodegradable polymer nanoparticles have attracted a considerable attention for their ability to function as a possible carrier for target-specific delivery of various drugs, genes, proteins, peptides, vaccines, and other biomolecules in humans without much toxicity. This review will specifically focus on the recent advances in polymer-based nanocarriers for various drugs and small silencing RNA's loading and delivery to treat different types of cancer.

Nanoparticles as Drug Delivery Systems in Cancer Medicine: Emphasis on RNAi-Containing Nanoliposomes

Nanomedicine is a growing research field dealing with the creation and manipulation of materials at a nanometer scale for the better treatment, diagnosis and imaging of diseases. In cancer medicine, the use of nanoparticles as drug delivery systems has advanced the bioavailability, in vivo stability, intestinal absorption, solubility, sustained and targeted delivery, and therapeutic effectiveness of several anticancer agents. The expansion of novel nanoparticles for drug delivery is an exciting and challenging research filed, in particular for the delivery of emerging cancer therapies, including small interference RNA (siRNA) and microRNA (miRNAs)-based molecules. In this review, we focus on the currently available drug delivery systems for anticancer agents. In addition, we will discuss the promising use of nanoparticles for novel cancer treatment strategies.

Efficient production of retroviruses using PLGA/bPEI-DNA nanoparticles and application for reprogramming somatic cells

Reprogramming of somatic cells to pluripotent cells requires the introduction of factors driving fate switches. Viral delivery has been the most efficient method for generation of induced pluripotent stem cells. Transfection, which precedes virus production, is a commonly-used process for delivery of nucleic acids into cells. The aim of this study is to evaluate the efficiency of PLGA/ bPEI nanoparticles in transfection and virus production. Using a modified method of producing PLGA nanoparticles, PLGA/bPEI-DNA nanoparticles were examined for transfection efficiency and virus production yield in comparison with PLGA-DNA, bPEI-DNA nanoparticles or liposome-DNA complexes. After testing various ratios of PLGA, bPEI, and DNA, the ratio of 6:3:1 (PLGA:bPEI:DNA, w/w/w) was determined to be optimal, with acceptable cellular toxicity. PLGA/bPEI-DNA (6:3:1) nanoparticles showed superior transfection efficiency, especially in multiple gene transfection, and viral yield when compared with liposome-DNA complexes. The culture supernatants of HEK293FT cells transfected with PLGA/bPEI-DNA of viral constructs containing reprogramming factors (Oct4, Sox2, Klf4, or c-Myc) successfully and more efficiently generated induced pluripotent stem cell colonies from mouse embryonic fibroblasts. These results strongly suggest that PLGA/bPEI-DNA nanoparticles can provide significant advantages in studying the effect of multiple factor delivery such as in reprogramming or direct conversion of cell fate.

N-lauroyl chitosan surface-modified PLGA nanoparticles as carrier for adriamycin to overcome cancer drug resistance

N-lauroyl chitosan (NLCS) conjugates with different degrees of substitution (DS) of lauroyl group were synthesized and used to prepare surface modified poly(lactic-co-glycolic) acid (NLCS-PLGA) nanoparticles via hydrophobic interaction and ionic bond force. NLCS-PLGA nanoparticles had spherical shape with shell-core structure and exhibited the smallest size and narrowest size distribution when DS of lauroyl group of NLCS was 8.5%. Adriamycin (ADR), as a model antitumor drug, was loaded into NLCS-PLGA nanoaprticles and its initial burst release from PLGA nanoparticles was significantly reduced. MTT assay showed that NLCS-2-PLGA nanoaprticles evidently enhanced cytotoxicity of ADR against drug-resistant breast cancer MCF-7/ADR cells, both compared to free ADR and ADR-loaded PLGA nanoparticles. Moreover, cell-live images showed that the cellular uptake and nuclear location of ADR in MCF-7/ADR cells were significantly enhanced by loading of NLCS-2-PLGA nanoparticles. In conclusion, this novel carrier of anticancer drugs has the potential to overcome drug resistance in cancer cells.

Tumor imaging and interferon-γ-inducible protein-10 gene transfer using a highly efficient transferrin-conjugated liposome system in mice

PURPOSE

We have developed a PEGylated transferrin-conjugated liposomes (PTf-Ls) system for the combined tumor imaging and targeted delivery of the IFN-γ-inducible protein-10 (IP-10) gene in a single macromolecular construct. Here, we characterize and analyze the use of this system in a mouse model of breast cancer.

EXPERIMENTAL DESIGN

The biophysical and cell transfection properties of PTf-Ls were determined through a series of in vitro experiments. A nude mouse/breast cancer cell line xenograft model (mouse xenograft model) was used to image the tumor internalization of fluorescently labeled PTf-Ls. The clinical use of the system was tested by treating tumor-bearing mice with PTf-Ls loaded with IP-10 plasmid DNA or fluorescent lipoplexes.

RESULTS

The resulting 165-nm liposomes (zeta potential = -10.6 mV) displayed serum resistance, low cytotoxicity (<5%), and high transfection efficiency (≤82.8%) in cultured cells. Systemic intravenous administration of fluorescent PTf-Ls in the mouse xenograft model resulted in nanoparticle circulation for 72 hours, as well as selective and efficient internalization in tumor cells, according to in vivo fluorescence and bioluminescence analyses. Tumor fluorescence increased gradually up to 26 hours, whereas background fluorescence decreased to near-baseline levels. Treatment of mice with PTf-Ls entrapped pcDNA3.1-IP-10 suppressed tumor growth in mice by 79% on day 50 and increased the mean survival time of mice. Fluorescent pcDNA-IP-10-entrapped PTf-Ls showed good properties for simultaneous tumor-targeted imaging and gene-specific delivery in an animal tumor model.

CONCLUSIONS

Our developed transferrin-conjugated liposome system possesses promising characteristics for tumor-targeting, imaging, and gene therapy applications.

Strategies to deliver microRNAs as potential therapeutics in the treatment of cardiovascular pathology

CONTEXT

MicroRNAs (miRNAs) are important and powerful mediators in a variety of diseases including cardiovascular pathology. Thus, they emerged as interesting new drug targets. However, it is important to develop efficient transfer tools to successfully deliver miRNAs or antisense oligonucleotides (antagomirs) to the target tissue.

OBJECTIVE

The aim of this study was to review the scientific literature on delivery techniques currently used for transfer of miRNAs and antagomirs to animal models of cardiovascular disease and those that are likely to be used for therapeutic miRNA transport in the nearest future.

METHODS

The research was carried out by consulting the following medical websites: Medicus Medline Index, PubMed (National Library of Medicine), and a registry database of clinical trials conducted in USA ( www.clinicaltrials.gov). The selection gathers articles written in English, published from January 2012.

RESULTS

A current delivery technique includes chemical modification of antagomirs with 2-O-methyl-group or 2-O-methyoxyethyl or using locked nucleic acids to increase drug stability and affinity. Development of miRNA sponges/decoys aims to target all members of a miRNA seed family of interest. A further strategy to augment miRNA levels is to use miRNA delivery through viral-based vectors including adenoviruses, adeno-associated viruses, and lentiviruses. To date, a variety of nanocarriers is available for efficient delivery of miRNAs. Microvesicles, and apoptotic bodies that contain circulating miRNAs could be also used as therapeutic transport systems in the nearest future.

CONCLUSION

Development of new miRNA carrier systems with advanced properties and large animal data in the cardiovascular field is highly recommended.

MicroRNA in carcinogenesis & cancer diagnostics: a new paradigm

MicroRNAs (miRNAs) are small 22-25 nucleotides long non-coding RNAs, that are conserved during evolution, and control gene expression in metazoan animals, plants, viruses, and bacteria primarily at post-transcriptional and transcriptional levels. MiRNAs ultimately regulate target gene expression by degrading the corresponding mRNA and/or inhibiting their translation. Currently, the critical functions of miRNAs have been established in regulating immune system, cell proliferation, differentiation and development, cancer and cell cycle by as yet unknown control mechanism. MiRNAs play an essential role in malignancy, and as tumour suppressors and oncogenes. Thus, discovery of new miRNAs will probably change the landscape of cancer genetics. Significantly different miRNA profiles can be assigned to various types of tumours, which could serve as phenotypic signatures for different cancers for their exploitation in cancer diagnostics, prognostics and therapeutics. If miRNA profiles can accurately predict malignancies, this technology could be exploited as a tool to surmount the diagnostic challenges. This review provides comprehensive and systematic information on miRNA biogenesis and their implications in human health.

Formulation approaches to short interfering RNA and MicroRNA: challenges and implications

RNA interference has emerged as a potentially powerful tool in the treatment of genetic and acquired diseases by delivering short interfering RNA (siRNA) or microRNA (miRNA) to target genes, resulting in their silencing. However, many physicochemical and biological barriers have to be overcome to obtain efficient in vivo delivery of siRNA and miRNA molecules to the organ/tissue of interest, thereby enabling their effective clinical therapy. This review discusses the challenges associated with the use of siRNA and miRNA and describes the nonviral delivery strategies used in overcoming these barriers. More specifically, emphasis has been placed on those technologies that have progressed to clinical trials for both local and systemic siRNA and miRNA delivery.

Treating colon cancer with a suicide gene delivered by self-assembled cationic MPEG-PCL micelles

Biodegradable cationic micelles show promise for applications in gene delivery. In this article, we used DOTAP to modify monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL, MP) micelles in one step, creating novel cationic self-assembled DOTAP and MPEG-PCL hybrid micelles (DMP). These micelles had a mean particle size of 46 ± 5.6 nm and a zeta potential of 41.8 ± 0.5 mV, and had the capacity to bind DNA. Compared with PEI25K (the gold standard), DMP micelles had higher transfection efficiency and lower cytotoxicity. Moreover, we used DMP to deliver the Survivin-T34A gene (S-T34A, a suicide gene) to treat colon cancer. DMP delivered the Survivin-T34A gene (DMP/S-T34A) and could induce apoptosis in cancer cells, resulting in inhibition of the growth of C-26 colon cancer cells in vitro. An in vivo study indicated that intraperitoneal administration of DMP micelles delivered the Survivin-T34A gene and efficiently inhibited the growth of abdominal metastatic C-26 colon cancer and the malignant ascites. These data suggest that DMP may be a novel gene carrier, and its delivery of the S-T34A gene may have promising applications in the treatment of colon cancer.