A Novel Peptide-Equipped Exosomes Platform for Delivery of Antisense Oligonucleotides

Exosomes are natural delivery vehicles because of their original feature such as low immunogenicity, excellent biocompatibility, and migration capability. Engineering exosomes with appropriate ligands are effective approaches to improve the low cellular uptake efficiency of exosomes. However, current strategies face considerable challenges due to the tedious and labor-intensive operational process. Here, we designed a novel peptides-equipped exosomes platform which can be assembled under convenient and mild reaction condition. Cell-penetrating peptides (CPPs) was conjugated on HepG2 cells-derived exosomes surface which can not only enhance the penetrating capacity of exosomes but also assist exosomes in loading antisense oligonucleotides (ASOs). The cellular uptake mechanism was investigated and we compared the difference between natural exosomes and modified exosomes. The resulting nanosystem demonstrated a preferential tropism for cells that are parented to their source tumor cells and could remarkably increase the cellular delivery of G3139 with efficient downregulation of antiapoptotic Bcl-2. This work developed a rapid strategy for intracellular delivery of nucleic acids, thus providing more possibilities toward personalized cancer medicine.

Targeting Listeria monocytogenes consensus sequence of internalin genes using an antisense molecule

As an intracellular pathogen, Listeria monocytogenes can enter host cells where it can replicate and escape detection and eradication by the host immune response making the clearance of infection very challenging. Furthermore, with the advent of antimicrobial resistance, the need for alternative targets is inevitable. Internalin proteins are crucial to this bacterium as they contribute to bacterial entry to the systemic circulation. In this study, we targeted a highly conserved region of these proteins by an antisense sequence that was covalently conjugated to the cell penetrating peptides (CPP) to overcome the challenging delivery barriers. Then, we evaluated the efficiency of this construct in vitro. We also assessed the antigenicity, cytotoxicity, and probability of apoptosis induction by this construct. The studied CPP-PNA inhibited bacterial growth and suppressed the mRNA expression of internalins in a dose-dependent manner. In addition, at all studied concentrations, CPP-PNA significantly reduced the invasion rate of L. monocytogenes in the examined cell lines. Moreover, different concentrations of CPP-PNA did not have a significant antigenic, cytotoxic, and apoptotic properties compared to the control. These results suggest the effectiveness of CPP-antisense in targeting the mRNAs of internalins for various research, therapeutic and preventive purposes. However, additional research is required to evaluate the potency, safety, and pharmacokinetics of this compound for the prevention and treatment of listeriosis.

Antisense Oligodeoxynucleotide-Mediated Gene Knockdown in Pollen Tubes

Specific gene knockdown mediated by the antisense oligodeoxynucleotides (AODNs) strategy emerged as a rapid and effective tool for probing gene role in plant cells, particularly tip-growing pollen tubes. Here, we describe the protocol for the successful employment of AODN technique in growing tobacco pollen tubes, covering AODN design, application, and analysis of the results. We also discuss the advantages and drawbacks of this method.

Characterizing the interaction between insulin-like growth factor 2 mRNA-binding protein 1 (IMP1) and KRAS expression

Insulin-like growth factor 2 mRNA-binding protein-1 (IMP1) has high affinity for KRAS mRNA, and it can regulate KRAS expression in cells. We first characterized the molecular interaction between IMP1 and KRAS mRNA. Using IMP1 variants with a point mutation in the GXXG motif at each KH domain, we showed that all KH domains play a critical role in the binding of KRAS RNA. We mapped the IMP1-binding sites on KRAS mRNA and show that IMP1 has the highest affinity for nts 1-185. Although it has lower affinity, IMP1 does bind to other coding regions and the 3'-UTR of KRAS mRNA. Eight antisense oligonucleotides (AONs) were designed against KRAS RNA in the nts 1-185 region, but only two, SM6 and SM7, show potent inhibition of the IMP1-KRAS RNA interaction in vitro To test the activity of these two AONs in SW480 human colon cancer cells, we used 2'-O-methyl-modified versions of SM6 and SM7 in an attempt to down-regulate KRAS expression. To our surprise, both SM6 and SM7 had no effect on KRAS mRNA and protein expression, but significantly inhibited IMP1 protein expression without altering IMP1 mRNA level. On the other hand, knockdown of IMP1 using siRNA lowered the expression of KRAS. Using Renilla luciferase as a reporter, we found that IMP1 translation is significantly reduced in SM7-treated cells with no change in let-7a levels. The present study shows that the regulation of KRAS expression by IMP1 is complex and may involve both the IMP1 protein and its mRNA transcript.

Novel lipid modifying drugs to lower LDL cholesterol

PURPOSE OF REVIEW

Statins have long been the cornerstone for the prevention of cardiovascular disease (CVD). However, because of perceived adverse effects and insufficient efficacy in certain groups of patients, considerable interest exists in the search for alternatives to lower LDL-cholesterol (LDL-C), and the recent approvals of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors underlines the success of this quest. Here, we give an updated overview on the most recent developments in the area of LDL-C lowering agents.

RECENT FINDINGS

The clinical effects of the PCSK9 inhibitors are promising, especially now that the FOURIER and SPIRE programmes are published. Most cholesterylester-transfer protein inhibitors, however, except anacetrapib, have been discontinued because of either toxicity or lack of efficacy in large cardiovascular outcome trials. Other agents - like mipomersen, lomitapide, ETC-1002, and gemcabene - aim to lower LDL-C in different ways than solely through the LDL receptor, opening up possibilities for treating patients not responding to conventional therapies. New discoveries are also being made at the DNA and RNA level, with mipomersen being the first approved therapy based on RNA intervention in the United States for homozygous familial hypercholesterolemia.

SUMMARY

Recent years have witnessed a new beginning for cholesterol-lowering compounds. With increased knowledge of lipid metabolism a score of new therapeutic targets has been identified. Mechanisms for modulation of those targets are also becoming more diverse while statins remain the backbone of CVD prevention, the new alternatives, such as PCSK9 monoclonals will probably play an important additional role in treatment of patients at risk for CVD.

Targeting noncoding RNAs in disease

Many RNA species have been identified as important players in the development of chronic diseases, including cancer. Over the past decade, numerous studies have highlighted how regulatory RNAs such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) play crucial roles in the development of a disease state. It is clear that the aberrant expression of miRNAs promotes tumor initiation and progression, is linked with cardiac dysfunction, allows for the improper physiological response in maintaining glucose and insulin levels, and can prevent the appropriate integration of neuronal networks, resulting in neurodegenerative disorders. Because of this, there has been a major effort to therapeutically target these noncoding RNAs. In just the past 5 years, over 100 antisense oligonucleotide-based therapies have been tested in phase I clinical trials, a quarter of which have reached phase II/III. Most notable are fomivirsen and mipomersen, which have received FDA approval to treat cytomegalovirus retinitis and high blood cholesterol, respectively. The continued improvement of innovative RNA modifications and delivery entities, such as nanoparticles, will aid in the development of future RNA-based therapeutics for a broader range of chronic diseases. Here we summarize the latest promises and challenges of targeting noncoding RNAs in disease.

Antihyperalgesic effect of CB1 receptor activation involves the modulation of P2X3 receptor in the primary afferent neuron

Cannabinoid system is a potential target for pain control. Cannabinoid receptor 1 (CB₁) activation play a role in the analgesic effect of cannabinoids once it is expressed in primary afferent neurons. This study investigates whether the anti-hyperalgesic effect of CB₁ receptor activation involves P2X₃ receptor in primary afferent neurons. Mechanical hyperalgesia was evaluated by electronic von Frey test. Cannabinoid effect was evaluated using anandamide or ACEA, a non-selective or a selective CB₁ receptor agonists, respectively; AM251, a CB₁ receptor antagonist, and antisense ODN for CB₁ receptor. Calcium imaging assay was performed to evaluated α,β-meATP-responsive cultured DRG neurons pretreated with ACEA. Anandamide or ACEA administered in peripheral tissue reduced the carrageenan-induced mechanical hyperalgesia. The reduction in the carrageenan-induced hyperalgesia induced by ACEA was completely reversed by administration of AM251 as well as by the intrathecal treatment with antisense ODN for CB₁ receptor. Also, ACEA reduced the mechanical hyperalgesia induced by bradykinin and by α,β-meATP, a P2X₃ receptor non-selective agonist, but not by tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β) and chemokine-induced chemoattractant-1 (CINC-1). Finally, CB₁ receptors are co-localized with P2X₃ receptors in DRG small-diameter neurons and the treatment with ACEA reduced the number of α,β-meATP-responsive cultured DRG neurons. Our data suggest that the analgesic effect of CB₁ receptor activation is mediated by a negative modulation of the P2X₃ receptor in the primary afferent neurons.

Modulation of LMNA splicing as a strategy to treat prelamin A diseases

The alternatively spliced products of LMNA, lamin C and prelamin A (the precursor to lamin A), are produced in similar amounts in most tissues and have largely redundant functions. This redundancy suggests that diseases, such as Hutchinson-Gilford progeria syndrome (HGPS), that are caused by prelamin A-specific mutations could be treated by shifting the output of LMNA more toward lamin C. Here, we investigated mechanisms that regulate LMNA mRNA alternative splicing and assessed the feasibility of reducing prelamin A expression in vivo. We identified an exon 11 antisense oligonucleotide (ASO) that increased lamin C production at the expense of prelamin A when transfected into mouse and human fibroblasts. The same ASO also reduced the expression of progerin, the mutant prelamin A protein in HGPS, in fibroblasts derived from patients with HGPS. Mechanistic studies revealed that the exon 11 sequences contain binding sites for serine/arginine-rich splicing factor 2 (SRSF2), and SRSF2 knockdown lowered lamin A production in cells and in murine tissues. Moreover, administration of the exon 11 ASO reduced lamin A expression in wild-type mice and progerin expression in an HGPS mouse model. Together, these studies identify ASO-mediated reduction of prelamin A as a potential strategy to treat prelamin A-specific diseases.

Enhancement of glioma-specific immunity in mice by "NOBEL", an insulin-like growth factor 1 receptor antisense oligodeoxynucleotide

Autologous glioblastoma multiforme tumor cells treated with an antisense oligodeoxynucleotide (AS-ODN) targeting insulin-like growth factor receptor-1 (IGF-1R) are the basis of a vaccine with therapeutic effects on tumor recurrence in a pilot clinical trial. As a preface to continued clinical investigation of this vaccination strategy, we have studied the contribution of an optimized IGF-1R AS-ODN, designated "NOBEL", to the induction of immunity to mouse GL261 glioma cells. The impact of NOBEL on mechanisms contributing to the development of GL261 immunity was first examined in the periphery. GL261 cells are naturally immunogenic when implanted into the flanks of congenic C57BL/6 mice, immunizing rather than forming tumors in around 50 % of these animals but causing tumors in the majority of mice lacking T and B lymphocytes. Overnight treatment with NOBEL in vitro reduces IGF-1R expression by GL261 cells but has minimal effect on cell viability and does not reduce the capacity of the cells to form tumors upon implantation. In contrast, tumors are extremely rare when GL261 cells are mixed with NOBEL at inoculation into the flanks of C57BL/6, and the recipient mice become immune to subcutaneous and intracranial challenge with untreated GL261. Adaptive immune mechanisms contribute to this effect, as immunocompromised mice fail to either fully control tumor formation or develop immunity following flank administration of the GL261/NOBEL mix. NOBEL's structure has known immunostimulatory motifs that likely contribute to the immunogenicity of the mix, but its specificity for IGF-1R mRNA is also important as a similarly structured sense molecule is not effective.

Glioblastoma exosomes and IGF-1R/AS-ODN are immunogenic stimuli in a translational research immunotherapy paradigm

Glioblastomas are primary intracranial tumors for which there is no cure. Patients receiving standard of care, chemotherapy and irradiation, survive approximately 15 months prompting studies of alternative therapies including vaccination. In a pilot study, a vaccine consisting of Lucite diffusion chambers containing irradiated autologous tumor cells pre-treated with an antisense oligodeoxynucleotide (AS-ODN) directed against the insulin-like growth factor type 1 receptor was found to elicit positive clinical responses in 8/12 patients when implanted in the rectus sheath for 24 h. Our preliminary observations supported an immune response, and we have since reopened a second Phase 1 trial to assess this possibility among other exploratory objectives. The current study makes use of a murine glioma model and samples from glioblastoma patients in this second Phase 1 trial to investigate this novel therapeutic intervention more thoroughly. Implantation of the chamber-based vaccine protected mice from tumor challenge, and we posit this occurred through the release of immunostimulatory AS-ODN and antigen-bearing exosomes. Exosomes secreted by glioblastoma cultures are immunogenic, eliciting and binding antibodies present in the sera of immunized mice. Similarly, exosomes released by human glioblastoma cells bear antigens recognized by the sera of 6/12 patients with recurrent glioblastomas. These results suggest that the release of AS-ODN together with selective release of exosomes from glioblastoma cells implanted in chambers may drive the therapeutic effect seen in the pilot vaccine trial.

A selection strategy in plant transformation based on antisense oligodeoxynucleotide inhibition

Antisense oligodeoxynucleotide (asODN) inhibition was developed in the 1970s, and since then has been widely used in animal research. However, in plant biology, the method has had limited application because plant cell walls significantly block efficient uptake of asODN to plant cells. Recently, we have found that asODN uptake is enhanced in a sugar solution. The method has promise for many applications, such as a rapid alternative to time-consuming transgenic studies, and high potential for studying gene functionality in intact plants and multiple plant species, with particular advantages in evaluating the roles of multiple gene family members. Generation of transgenic plants relies on the ability to select transformed cells. This screening process is based on co-introduction of marker genes into the plant cell together with a gene of interest. Currently, the most common marker genes are those that confer antibiotic or herbicide resistance. The possibility that traits introduced by selectable marker genes in transgenic field crops may be transferred horizontally is of major public concern. Marker genes that increase use of antibiotics and herbicides may increase development of antibiotic-resistant bacterial strains or contribute to weed resistance. Here, we describe a method for selection of transformed plant cells based on asODN inhibition. The method enables selective and high-throughput screening for transformed cells without conferring new traits or functions to the transgenic plants. Due to their high binding specificity, asODNs may also find applications as plant-specific DNA herbicides.

Protein interactions in Xenopus germ plasm RNP particles

Hermes is an RNA-binding protein that we have previously reported to be found in the ribonucleoprotein (RNP) particles of Xenopus germ plasm, where it is associated with various RNAs, including that encoding the germ line determinant Nanos1. To further define the composition of these RNPs, we performed a screen for Hermes-binding partners using the yeast two-hybrid system. We have identified and validated four proteins that interact with Hermes in germ plasm: two isoforms of Xvelo1 (a homologue of zebrafish Bucky ball) and Rbm24b and Rbm42b, both RNA-binding proteins containing the RRM motif. GFP-Xvelo fusion proteins and their endogenous counterparts, identified with antisera, were found to localize with Hermes in the germ plasm particles of large oocytes and eggs. Only the larger Xvelo isoform was naturally found in the Balbiani body of previtellogenic oocytes. Bimolecular fluorescence complementation (BiFC) experiments confirmed that Hermes and the Xvelo variants interact in germ plasm, as do Rbm24b and 42b. Depletion of the shorter Xvelo variant with antisense oligonucleotides caused a decrease in the size of germ plasm aggregates and loosening of associated mitochondria from these structures. This suggests that the short Xvelo variant, or less likely its RNA, has a role in organizing and maintaining the integrity of germ plasm in Xenopus oocytes. While GFP fusion proteins for Rbm24b and 42b did not localize into germ plasm as specifically as Hermes or Xvelo, BiFC analysis indicated that both interact with Hermes in germ plasm RNPs. They are very stable in the face of RNA depletion, but additive effects of combinations of antisense oligos suggest they may have a role in germ plasm structure and may influence the ability of Hermes protein to effectively enter RNP particles.

[The apoptosis effect of antisense oligodeoxynucleotides targeting ATM on the laryngeal squamous cell carcinoma treated with radiation]

OBJECTIVE

To designed antisense oligodeoxynucleotides (AS-ODNs) to reduce the expression of ATM and to study its effect on the apoptosis of Hep-2 (human epidermoid laryngeal carcinoma) cells treated with radiation in vitro.

METHODS

Experiment was divided into AS-Lipo, Sen-Lipo, Mis-Lipo, Lipo and Hep-2 group. The expression of ATM mRNA in Hep-2 cells was examined by real-time quantitative PCR. About 18 hours after transfection, they were irradiated simultaneously with different doses of X-ray radiation (0, 2, 4, 6, and 8 Gy) respectively. Clonogenic survival assay was carried out to detect the survival ability of Hep-2 cells after irradiation. After exposed to 4 Gy radiation, flow cytometry was carried out to analyze the cell apoptosis.

RESULTS

The relative ATM mRNA expression in Hep-2 cells treated with ATM AS-ODNs was decreased to (11.03 +/- 2.51)% which was much lower than that of untreated cells (P < 0.05). After irradiation, the survival fraction (SF) of cells treated with ATM AS-ODNs was lower than that of other groups at the same dose of radiation. There was statistical significance between the group treated with ATM AS-ODNs and other groups (P < 0.05). The apoptotic rate for the group irradiated with ATM AS-ODNs was (30.7 +/- 1.31)%, which was significantly higher than that of others (P < 0.05).

CONCLUSION

AS-ODNs of ATM reduce ATM mRNA expression and enhance Hep-2 cells apoptosis to radiation in vitro.

Antisense oligodeoxynucleotide inhibition as an alternative and convenient method for gene function analysis in pollen tubes

Antisense oligodeoxynucleotide (A-ODN) inhibition works well in animal cells. However, there have been few successful examples to date of its application in plants, and more specifically whether the technique can be used in pollen tubes as a model of plant cell growth. NtGNL1 plays an important role in pollen tube development and was thus selected as an indicator to assess the biological effects of A-ODN. An A-ODN inhibition technique was used to down-regulate NtGNL1 expression in tobacco pollen tubes and showed that A-ODNs could quickly enter pollen tubes through the thick wall and cell membrane and effectively block NtGNL1 expression. Phenotype analysis revealed that the down-regulation of NtGNL1 by A-ODNs resulted in abnormalities in endocytosis and subsequent vesicle trafficking, similar to the phenotypes of pollen tubes treated with NtGNL1 RNAi. This investigation confirmed that A-ODNs could specifically inhibit target gene expression, and furthermore demonstrated that A-ODN functioned in a concentration- and duration-dependent manner, because A-ODNs could be degraded when incubated with pollen tubes. Thus, the A-ODN technique was successfully used for gene function analysis in pollen tubes and appears to be an alternative and convenient technique when the in vitro pollen tube is used as the study model. This technique will greatly facilitate investigations on the molecular mechanism(s) underlying pollen tube growth.

Gene silencing by gold nanoshell-mediated delivery and laser-triggered release of antisense oligonucleotide and siRNA

RNA interference (RNAi)--using antisense DNA or RNA oligonucleotides to silence activity of a specific pathogenic gene transcript and reduce expression of the encoded protein--is very useful in dissecting genetic function and holds significant promise as a molecular therapeutic. A major obstacle in achieving gene silencing with RNAi technology is the systemic delivery of therapeutic oligonucleotides. Here we demonstrate an engineered gold nanoshell (NS)-based therapeutic oligonucleotide delivery vehicle, designed to release its cargo on demand upon illumination with a near-infrared (NIR) laser. A poly-L-lysine peptide (PLL) epilayer covalently attached to the NS surface (NS-PLL) is used to capture intact, single-stranded antisense DNA oligonucleotides, or alternatively, double-stranded short-interfering RNA (siRNA) molecules. Controlled release of the captured therapeutic oligonucleotides in each case is accomplished by continuous wave NIR laser irradiation at 800 nm, near the resonance wavelength of the nanoshell. Fluorescently tagged oligonucleotides were used to monitor the time-dependent release process and light-triggered endosomal release. A green fluorescent protein (GFP)-expressing human lung cancer H1299 cell line was used to determine cellular uptake and gene silencing mediated by the NS-PLL carrying GFP gene-specific single-stranded DNA antisense oligonucleotide (AON-GFP), or a double-stranded siRNA (siRNA-GFP), in vitro. Light-triggered delivery resulted in ~47% and ~49% downregulation of the targeted GFP expression by AON-GFP and siRNA-GFP, respectively. Cytotoxicity induced by both the NS-PLL delivery vector and by laser irradiation is minimal, as demonstrated by a XTT cell proliferation assay.

Single-stranded RNAs use RNAi to potently and allele-selectively inhibit mutant huntingtin expression

Mutant huntingtin (HTT) protein causes Huntington disease (HD), an incurable neurological disorder. Silencing mutant HTT using nucleic acids would eliminate the root cause of HD. Developing nucleic acid drugs is challenging, and an ideal clinical approach to gene silencing would combine the simplicity of single-stranded antisense oligonucleotides with the efficiency of RNAi. Here, we describe RNAi by single-stranded siRNAs (ss-siRNAs). ss-siRNAs are potent (>100-fold more than unmodified RNA) and allele-selective (>30-fold) inhibitors of mutant HTT expression in cells derived from HD patients. Strategic placement of mismatched bases mimics micro-RNA recognition and optimizes discrimination between mutant and wild-type alleles. ss-siRNAs require Argonaute protein and function through the RNAi pathway. Intraventricular infusion of ss-siRNA produced selective silencing of the mutant HTT allele throughout the brain in a mouse HD model. These data demonstrate that chemically modified ss-siRNAs function through the RNAi pathway and provide allele-selective compounds for clinical development.

Sexual responses of the male rat medial preoptic area and medial amygdala to estrogen I: site specific suppression of estrogen receptor alpha

Male rat copulation is mediated by estrogen-sensitive neurons in the medial preoptic area (MPO) and medial amygdala (MEA); however, the mechanisms through which estradiol (E(2)) acts are not fully understood. We hypothesized that E(2) acts through estrogen receptor α (ERα) in the MPO and MEA to promote male mating behavior. Antisense oligodeoxynucleotides (AS-ODN) complementary to ERα mRNA were bilaterally infused via minipumps into either brain area to block the synthesis of ERα, which we predicted would reduce mating. Western blot analysis and immunocytochemistry revealed a knockdown of ERα expression in each brain region; however, compared to saline controls, males receiving AS-ODN to the MPO showed significant reductions in all components of mating, whereas males receiving AS-ODN to the MEA continued to mate normally. These results suggest that E(2) acts differently in these brain regions to promote the expression of male rat sexual behavior and that ERα in the MPO, but not in the MEA, promotes mating.

Novel basic protein, PfN23, functions as key macromolecule during nacre formation

The fine microstructure of nacre (mother of pearl) illustrates the beauty of nature. Proteins found in nacre were believed to be "natural hands" that control nacre formation. In the classical view of nacre formation, nucleation of the main minerals, calcium carbonate, is induced on and by the acidic proteins in nacre. However, the basic proteins were not expected to be components of nacre. Here, we reported that a novel basic protein, PfN23, was a key accelerator in the control over crystal growth in nacre. The expression profile, in situ immunostaining, and in vitro immunodetection assays showed that PfN23 was localized within calcium carbonate crystals in the nacre. Knocking down the expression of PfN23 in adults via double-stranded RNA injection led to a disordered nacre surface in adults. Blocking the translation of PfN23 in embryos using morpholino oligomers led to the arrest of larval development. The in vitro crystallization assay showed that PfN23 increases the rate of calcium carbonate deposition and induced the formation of aragonite crystals with characteristics close to nacre. In addition, we constructed the peptides and truncations of different regions of this protein and found that the positively charged C-terminal region was a key region for the function of PfN23 Taken together, the basic protein PfN23 may be a key accelerator in the control of crystal growth in nacre. This provides a valuable balance to the classic view that acidic proteins control calcium carbonate deposition in nacre.

[Mitochondrial mechanisms of antisense oligodeoxynucleotide Stat3 induced apoptosis in laryngeal carcinoma cell]

OBJECTIVE

To investigate the changes of mitochondrion by transferring antisense oligodeoxynucleotide Stat3 into laryngeal carcinoma Hep-2 cell, for elucidating the mechanism of laryngeal carcinoma Hep-2 cell apoptosis, for developing more effective treatment for laryngeal cancer.

METHOD

The designed Stat3 ASODN was transferred into laryngeal carcinoma Hep-2 cell by lipofection. Mitochondrion membrane potential, VDAC and Cyt-c were detected for determining the changes of mitochondrion.

RESULT

MMP was fell, Cyt-c and VDAC were increased with the heighten concentration of ASODN.

CONCLUSION

Mitochondria approach play an important role in the apoptosis mechanism of human Hep-2 cell by Stat3. This research elucidated the regulating mechanism of Hep-2 cell proliferation by Stat3, provided a new research focus for clinical therapy.

Silencing of gene expression by gymnotic delivery of antisense oligonucleotides

Antisense oligodeoxyribonucleotides have been used for decades to achieve sequence-specific silencing of gene expression. However, all early generation oligonucleotides (e.g., those with no other modifications than the phosphorothioate backbone) are inactive in vitro unless administered using a delivery vehicle. These delivery vehicles are usually lipidic but can also be polyamines or some other particulate reagent. We have found that by employing locked nucleic acid (LNA) phosphorothioate gap-mer nucleic acids of 16 mer or less in length, and by carefully controlling the plating conditions of the target cells and duration of the experiment, sequence-specific gene silencing can be achieved at low micromolar concentrations in vitro in the absence of any delivery vehicle. This process of naked oligonucleotide delivery to achieve gene silencing in vivo, which we have termed gymnosis, has been observed in many both adherent and nonadherent cell lines against several different targets genes.

Characterization of a scavenger receptor cysteine-rich-domain-containing protein of the starfish, Asterina pectinifera: ApSRCR1 acts as an opsonin in the larval and adult innate immune systems

Proteins containing a scavenger receptor cysteine-rich (SRCR) domain (SRCR proteins) play an important role in the innate immune system of various metazoan animals. In the starfish Asterina pectinifera, mesenchyme cells and coelomocytes govern the two distinct innate immune systems of the larvae and adults, respectively. Here we identify a cDNA encoding a protein containing nine SRCR domains termed ApSRCR1, and present characterization of the molecular structure, expression, subcellular localization and function of ApSRCR1 protein during ontogenesis of this animal. ApSRCR1 protein is a membrane-type protein with a predicted molecular mass of approximately 120 kDa. During ontogenesis, ApSRCR1 protein is de novo synthesized and localizes to cytoplasmic vesicles in both mesenchyme cells and coelomocytes without translation of maternal mRNA; however, the net production and modification by N-glycosylation of ApSRCR1 protein differs in each cell type. In both types of cell, functional inhibition of ApSRCR1 protein leads to incompetent bacterial clearance and failure of aggregate formation. However, this inhibitory effect is weaker in the mesenchyme cells than in the coelomocytes. In the bacteria-sensitized adult, ApSRCR1 protein is up-regulated and digested to enable its secretion into the coelomic fluid. This secreted form of ApSRCR1 protein can apparently bind to bacteria. Overall, we show that ApSRCR1 protein is finely regulated for expression not only during development but also in a sensitive innate immunological situation, and thereupon acts as an opsonin for bacteria to different extents in the larvae and adults of A. pectinifera.

Nucleolin antisense oligodeoxynucleotides induce apoptosis and may be used as a potential drug for nasopharyngeal carcinoma therapy

Nucleolin (C23, NCL) mRNA was up-regulated in nasopharyngeal carcinoma (NPC) cells compared to that of normal nasomucosal (NNM) cells using a cDNA microarray approach. The level of nucleolin protein was also up-regulated in 13 NPC cell lines, 30 biopsy specimens and nine other cancer cell lines compared to five NNM cells or normal stromal cells, which were analyzed using immunoblotting or immunohistochemistry. We transfected nucleolin antisense oligodeoxynucleotides (phosphorothioate-modified oligodeoxynucleotides; S-ODNs) into NPC-TW01 cells to knockdown nucleolin expression to evaluate the function of nucleolin in cancer cells. Nucleolin knockdown induced NPC cells but not NNM cells to undergo apoptosis. Furthermore, treatment of NPC-TW01 xenograft tumors with nucleolin antisense oligodeoxynucleotides suppressed the growth of xenograft tumors without obvious side effects. Therefore, we suggest that nucleolin may be a potential cancer therapeutic target and that nucleolin antisense oligodeoxynucleotides may be used as a potential drug for therapy in NPC.

Low concentrations of bisphenol A induce mouse spermatogonial cell proliferation by G protein-coupled receptor 30 and estrogen receptor-α

BACKGROUND

Bisphenol A (BPA) is one of the most prevalent chemicals in daily-use materials; therefore, human exposure to BPA is ubiquitous. The estrogenicity of BPA is generally mediated by nuclear estrogen receptors (ERs). However, low concentrations of BPA stimulate seminoma cell proliferation by an uncertain mechanism that does not involve activation of ERs.

OBJECTIVE

We investigated the possible promoting effects of low-concentration BPA and the possible mechanism(s) using the murine ER-β negative spermatogonial GC-1 cell line.

METHODS AND RESULTS

Using the specific signaling inhibitor, BPA at test concentrations ranging from 10-10 to 10-8 M markedly induced proliferation of GC-1 cells by activating both cGMP-dependent protein kinase (PKG) and epidermal growth factor receptor (EGFR) extracellular regulated kinase (ERK) pathways. BPA stimulated a rapid (15-min) phosphorylation of the transcription factor cAMP response element binding protein (CREB) and the cell cycle regulator retinoblastoma protein (Rb). Interestingly, ER-α phosphorylation is involved in the proliferation, whereas BPA does not directly transactivate ER-α in gene reporter assays. Using specific agonists and gene silencing, we further observed that BPA mediates the proliferation and fos gene expression of GC-1 cells by G protein-coupled receptor 30 (GPR30) and ER-α.

CONCLUSIONS

Our data suggest that low concentrations of BPA activate the PKG and EGFR/ERK/c-fos pathways through a cross-talk between GPR30 and ER-α, which in turn stimulates GC-1 cell proliferation. The present study provides a novel insight regarding the potential role of GPR30 and ER-α in mediating the proliferative effects of BPA in male germ cells.

Neph3 associates with regulation of glomerular and neural development in zebrafish

Neph3 (filtrin) is a membrane protein expressed in the glomerular epithelial cells (podocytes), but its role in the glomerulus is still largely unknown. To characterize the function of Neph3 in the glomerulus, we employed the zebrafish as a model system. Here we show that the expression of neph3 in pronephros starts before the onset of nephrin and podocin expression, peaks when the nephron primordium differentiates into glomerulus and tubulus, and is then downregulated upon glomerular maturation. By histology, we found that neph3 is specifically expressed in pronephric podocytes at 36hpf. Furthermore, disruption of neph3 expression by antisense morpholino oligonucleotides results in distorted body curvature and transient pericardial edema, the latter likely reflecting perturbation of glomerular osmoregulatory function. Histological analysis of neph3 morphants reveals altered glomerular morphology and dilated pronephric tubules. The phenotype of neph3 morphants, curved body and pericardial edema, is rescued by wild-type zebrafish neph3 mRNA. In addition to glomerulus, neph3 is highly expressed in the developing brain and specific regions of mature midbrain and hindbrain. In line with this, neph3 morphants show aberrant brain morphology. Collectively, the expression of neph3 in glomerulus and brain together with the morphant phenotype imply that neph3 is a pleiotropic gene active during distinct stages of tissue differentiation and associates directly in the regulation of both glomerular and neural development.

Expression and function of osteopontin in vascular adventitial fibroblasts and pathological vascular remodeling

Osteopontin is known to play important roles in various diseases including vascular disorders. However, little is known about its expression and function in vascular adventitial fibroblasts. Adventitial fibroblasts have been shown to play a key role in pathological vascular remodeling associating with various vascular disorders. In this study, we measured activation of Osteopontin and its biological functions in cultured adventitial fibroblasts and injured rat carotid injury arteries induced by balloon angioplasty. Our results showed that angiotensin II and aldosterone increased Osteopontin expression in adventitial fibroblasts in a time- and concentration-dependent manner. MAPKs and AP-1 pathways were involved in Osteopontin upregulation. In addition, Adventitial fibroblast migration stimulated by Angiotensin II and aldosterone required OPN expression. Perivascular delivery of antisense oligonucleotide for Osteopontin suppressed neointimal formation post-injury. We concluded that upregulation of Osteopontin expression in adventitial fibroblasts might be important in the pathogenesis of vascular remodeling after arterial injury.

[Regulating action of iron regulatory protein-2 in iron metabolism of lung cancer]

OBJECTIVE

To discuss the regulating mechanism of iron regulatory protein-2 (IRP2) in the iron metabolism of lung cancer.

METHODS

The cultured A549 cells were divided into 3 groups: liposome group (including liposomes 20 mg/L), random oligonucleotide group (SCODN group) and antisense oligonucleotide group (ASODN group). And the liposome-mediated transfection was employed with the liposome and SCODN groups as controls. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to examine the mRNA and protein expressions of iron metabolism-related transferring (Tf), transferrin receptor (TfR) and ferritin (Fn) genes, etc.

RESULTS

After a 48-hour transfection, the mRNA expression of Tf had no statistically significant difference among three groups (F = 2.18, P = 0.078); the mRNA expression of TfR in the ASODN group was significantly lower than that in the liposome and SCODN groups (P < 0.05). The expression of Fn mRNA in the ASODN group (0.56 ± 0.06) was higher than that in the liposome (0.36 ± 0.05) and SCODN groups (0.39 ± 0.03) (P < 0.05). After a 48-hour transfection, the IRP2 protein expression of the ASODN group was significantly lower than those of the liposome and SCODN groups (P < 0.05). The Tf protein expression was not statistically different in three groups (F = 2.67, P = 0.088). The TfR protein expression of the ASODN group was lower than those of the liposome and SCODN groups (P < 0.05). And the Fn protein expression of the ASODN group was higher than those of the liposome and SCODN groups (P < 0.05).

CONCLUSION

IRP2 may affect the expressions of TfR and Fn in lung adenocarcinoma A549 cells by changing the amount of protein and regulating the iron metabolism.

[Effect of antisurvivin oligodeoxynucleotides on proliferation and apoptosis in gastric cancer cell line BGC-823 and the molecular mechanism]

OBJECTIVE

To explore the effects of antisense oligodeoxynucleotides (ASODN) on proliferation and apoptosis in gastric cancer cell line BGC-823 cells and the molecular mechanisms induced by ASODN.

METHODS

survivin ASODN-1, survivin ASODN-2 and survivin ASODN-3 were transfected into BGC-823 cells by Lipofectamine(TM) 2000 transfection reagent. The growth activity of BGC-823 cells was detected by MTT assay. Apoptosis index (AI), proliferation index (PI), cell cycle and expressions of survivin, VEGF and Smac/DIABLO proteins were detected by flow cytometry (FCM). The changes of survivin mRNA, VEGF mRNA and Smac/DIABLO mRNA were detected by RT-PCR.

RESULTS

The expression of survivin was down-regulated by the three ASODN sequences, especially the ASODN-2 was best. At 48 hours after transfection with 600 nmol/L survivin ASODN-2, the cells in G(1)/G(0) phase were significantly increased [(72.25 ± 2.95)%], apoptotic index increased [(11.31 ± 0.38)%], proliferation index decreased [(27.77 ± 2.97)%], compared with those in the control group [(56.25 ± 0.75)%, (1.62 ± 0.36)%, (43.80 ± 0.80)%, all P < 0.05]. The survivin mRNA and protein levels (0.523 ± 0.091, 0.733 ± 0.009) were down-regulated compared with those in the control group (0.861 ± 0.047, 0.997 ± 0.233), VEGF (0.519 ± 0.076, 0.75 ± 0.006) were down-regulated compared with those in the control group (0.779 ± 0.059, 1.000 ± 0.01), while those of Smac/DIABLO(0.899 ± 0.113, 1.637 ± 0.023)were up-regulated compared with those in the control group (0.558 ± 0.041, 1.000 ± 0.049, all P < 0.05).

CONCLUSIONS

Survivin ASODN can induce apoptosis and inhibit the proliferation of gastric cancer cell line BGC-823 cells. Those effects are induced through up-regulation of Smac/DIABLO and down-regulation of survivin and VEGF expression simultaneously.

Interfering with perirhinal brain-derived neurotrophic factor expression impairs recognition memory in rats

The role of brain-derived neurotrophic factor (BDNF) in recognition memory was investigated by locally infusing oligodeoxynucleotides (ODNs) into perirhinal cortex, a region of the temporal lobe essential for familiarity discrimination. Antisense but not sense BDNF ODN impaired consolidation of long-term (24 h) but not shorter-term (20 min) recognition memory.

[Knock-down of apollon gene by antisense oligodeoxynucleotide inhibits the proliferation of Lovo cells and enhances chemo-sensitivity]

In this study, the effects of apollon antisense oligodeoxynucleotide (ASODN) on the proliferation and apoptosis of human Lovo cells in vitro were investigated. Apollon ASODN was incubated with human colorectal Lovo cells for 48 h, the proliferation inhibition and the clone forming rates were detected by WST method and clone formation assay, respectively. The expression of apollon mRNA was analyzed by real time fluorescent quantitative reverse transcription polymerase chain reaction. The percentage of apoptotic cells and cell cycle distribution were determined by flow cytometry. The morphology of apoptotic cells was examined by fluorescence microscope. Lovo cells incubated with apollon ASODN combined with 5-fluorouracil (5-FU), cisplatin (DDP) or epirubicin (EPI) of different concentrations, cell proliferation inhibition rates were detected with WST method and IC50 was calculated. It was found that ASODN targeting apollon gene could all suppress the growth of Lovo cells and induce apoptosis of these cells significantly (P < 0.05). After Lovo cells treated with apollon ASODN for 48 hours, the expression of the apollon mRNA level was suppressed significantly. And a marked concentration-dependent decline of cell proliferation and clone forming, increasing of cell apoptosis levels were observed. The percentage of G0/G1 phage cells was abated and that of S phage cells was increased and the Lovo cells arrested at S phage of the cell cycle detected with flow cytometry. Many Lovo cells stained with Hoechst 33258 exhibited apoptotic morphology such as cell shrinkage, nuclear condensation and nuclear fragmentation. Cell proliferation inhibition was detected and their chemo-therapeutic effects of 5-FU, DDP and EPI on Lovo cells combined with apollon ASODN (0.08 micromol x L(-1)) were enhanced independently compared with single 5-FU, DDP and EPI groups, and the sensitivity enhanced about 2.58, 4.47, and 5.33 times respectively. It can be concluded that ASODN targeting apollon can suppress the expression of apollon mRNA, and inhibit the proliferation, induce apoptosis, arrest cell cycle at S phase of colorectal cancer Lovo cells in vitro and enhance the chemo-sensitivity to 5-FU, DDP and EPI.

Photothermal release of single-stranded DNA from the surface of gold nanoparticles through controlled denaturating and Au-S bond breaking

Photothermal release of DNA from gold nanoparticles either by thermolysis of the Au-S bonds used to anchor the oligonucleotides to the nanoparticle or by thermal denaturation has great therapeutic potential, however, both processes have limitations (a decreased particle stability for the former process and a prohibitively slow rate of release for the latter). Here we show that these two mechanisms are not mutually exclusive and can be controlled by adjusting laser power and ionic strength. We show this using two different double-stranded (ds)DNA-nanoparticle conjugates, in which either the anchored sense strand or the complementary antisense strand was labeled with a fluorescent marker. The amounts of release due to the two mechanisms were evaluated using fluorescence spectroscopy and capillary electrophoresis, which showed that irradiation of the decorated particles in 200 mM NaOAc containing 10 mM Mg(OAc)(2) with a pulsed 532 nm laser operating at 100 mW favors denaturation over Au-S cleavage to an extent of more than six-to-one. Due to the use of a pulsed laser, the process occurs on the order of minutes rather than hours, which is typical for continuous wave lasers. These findings encourage continued research toward developing photothermal gene therapeutics.

Therapeutic potential of antisense oligodeoxynucleotides in downregulating p53 oncogenic mutations in cancers

PURPOSE OF WORK

mutation of the p53 gene is the most common genetic alteration in human cancers. Our study proposes to rationally design a p53 antisense oligonucleotide (ASO) repository, which contains a series of ASOs containing single nucleotide differences to discriminate between each mutant and wild type (WT) p53. The Sfold software was used to predict target-accessibility and we designed an initial series of antisense oligonucleotides (ASO) that target the p53 mutants A161T, R175H and R249S. Western-blot analysis indicated that ASOs strongly inhibited the expression of p53 mutants in a panel of human tumor cell lines (SNU-449, SK-BR-3 and PLC/PRF/5) while having little effect on the expression of WT p53 (HepG2 cells). In three cancer lines harboring each of the p53 mutations, mutant-specific ASO treatment led to a dose-dependent inhibition of cell growth, cell viability, colony formation and invasion, and expression of mutant p53-dependent survival proteins. Our preliminary results indicate that a single nucleotide difference in ASOs can discriminate between mutant and WT p53. These observations support the hypothesis that a p53 ASO repository can be a potentially valuable tool to knock down oncogenic mutant p53 and warrant the testing of a p53 ASO repository in in vivo settings.

Zebrafish type XVII collagen: gene structures, expression profiles, and morpholino "knock-down" phenotypes

The human COL17A1 gene encodes type XVII collagen (also known as the 180-kDa bullous pemphigoid antigen), an integral component of hemidesmosomes, attachment complexes providing integrity to the dermal-epidermal junction. Zebrafish, a useful model system to study skin development, displays fully developed hemidesmosomes at approximately 5 days post-fertilization (dpf). We have identified two COL17A1 orthologues in the zebrafish genome, col17a1a and col17a1b, which are expressed in the skin and the neural system, respectively. The proteins coded by these genes have structural module organizations homologous to the human type XVII collagen. "Knock-down" of the expression of col17a1a with a specific morpholino targeting the 5' UTR of the gene resulted in a blistering phenotype and in perturbations in the basement membrane zone. "Knock-down" of col17a1b expression resulted in ablation or in marked reduction of neuromasts in the lateral line. Thus, zebrafish has two COL17A1 orthologues which may have evolved tissue-specific functions during vertebrate development. Collectively, zebrafish provides a model system to study the molecular aspects of skin development and offers insights into the corresponding human diseases.

Notch signaling, wt1 and foxc2 are key regulators of the podocyte gene regulatory network in Xenopus

Podocytes are highly specialized cells in the vertebrate kidney. They participate in the formation of the size-exclusion barrier of the glomerulus/glomus and recruit mesangial and endothelial cells to form a mature glomerulus. At least six transcription factors (wt1, foxc2, hey1, tcf21, lmx1b and mafb) are known to be involved in podocyte specification, but how they interact to drive the differentiation program is unknown. The Xenopus pronephros was used as a paradigm to address this question. All six podocyte transcription factors were systematically eliminated by antisense morpholino oligomers. Changes in the expression of the podocyte transcription factors and of four selected markers of terminal differentiation (nphs1, kirrel, ptpru and nphs2) were analyzed by in situ hybridization. The data were assembled into a transcriptional regulatory network for podocyte development. Although eliminating the six transcription factors individually interfered with aspects of podocyte development, no single gene regulated the entire differentiation program. Only the combined knockdown of wt1 and foxc2 resulted in a loss of all podocyte marker gene expression. Gain-of-function studies showed that wt1 and foxc2 were sufficient to increase podocyte gene expression within the glomus proper. However, the combination of wt1, foxc2 and Notch signaling was required for ectopic expression in ventral marginal zone explants. Together, this approach demonstrates how complex interactions are required for the correct spatiotemporal execution of the podocyte gene expression program.

[Stat3 antisense oligodeoxynucleotide induces apoptosis in laryngeal carcinoma cells by regulating apoptosis-related factors]

OBJECTIVE

To study the mechanism of apoptosis in laryngeal carcinoma cell induced by Stat3 antisense oligodeoxynucleotide (ASODN).

METHOD

The designed Stat3 ASODN was transferred into laryngeal carcinoma Hep-2 cell by lipofection. Expression of Bcl-2, Bax and C-Myc were detected by Western blot and PCR.

RESULT

Western blot and PCR results demonstrated that Stat3 ASODN could significantly increased the expression of Bax and decreased the expression of Bcl-2 and C-Myc when the concentration of antisense oligodeoxynucleotide were heightened.

CONCLUSION

Stat3 ASODN participate in apoptosis by enhancing the expression of Bax and reducing the expression of Bcl-2 and C-Myc.

Disulfide-linked liposomes: effective delivery vehicle for Bcl-2 antisense oligodeoxyribonucleotide G3139

BACKGROUND

Disulfide-linked oligodeoxyribonucleotide (ODN) liposomes were formulated and evaluated for the delivery of antisense ODN G3139 in KB human oral carcinoma cells.

MATERIALS AND METHODS

Liposomes composed of 1,2-di-(9Z-octadecenoyl)-3-trimethylammo-nium-propane (DOTAP)/egg phosphatidylcholine/alpha-tocopheryl polyethylene glycol 1000 succinate were incorporated with hydrophobized disulfide-linked ODN. Disulfide-linked ODN liposomes were characterized for their size, ODN intracellular delivery, Bcl-2 mRNA and protein expression, growth inhibition, and chemosensitization.

RESULTS

Intracellular delivery of ODN with disulfide-linked ODN liposomes was more efficient than that with non-liposomal hydrophobized disulfide-linked ODN. Treatment of the cells with disulfide-linked ODN liposomes resulted in efficient Bcl-2 down-regulation greater than that with hydrophobized disulfide-linked ODN and consistent with that of cellular growth inhibition and the sensitization to daunorubicin in KB cells. Disulfide-linked ODN liposomes exhibited superior colloidal stability during 5-week storage.

CONCLUSION

Disulfide-linked liposomes are effective delivery vehicles for antisense ODN.

Antisense inhibition of enolase strongly limits the metabolism of aromatic amino acids, but has only minor effects on respiration in leaves of transgenic tobacco plants

Enolase catalyses the reversible conversion of 2-phosphoglycerate and phosphoenolpyruvate in glycolysis. Phosphoenolpyruvate constitutes an important branch point in plant metabolism. It is converted to pyruvate by pyruvate kinase and organic acids by phosphoenolpyruvate carboxylase. Phosphoenolpyruvate also acts as a precursor for the synthesis of aromatic amino acids in plastids. Tobacco (Nicotiana tabacum) enolase antisense plants were analysed for changes in metabolite composition, respiration and photosynthetic parameters. Antisense repression resulted in up to a 95% reduction in total enolase activity. It also resulted in fundamental changes in foliar metabolism. Although 2-phosphoglycerate remained largely unaltered, there was a substantial decrease in phosphoenolpyruvate. The levels of aromatic amino acids and secondary phenylpropanoid metabolites that are derived from these compounds decreased strongly, as did branched chain amino acids. The level of pyruvate was unaltered, as was the rate of respiration. There were substantial increases in tricarboxylic acid cycle intermediates, including a 16-fold increase in isocitrate, an increase in the total free amino acid content, including a 14-fold increase in asparagine and glutamine, and a 50% decrease in free sugars. We conclude that a decrease in enolase activity affects secondary pathways, such as the shikimate branch of amino acid biosynthesis, but does not inhibit the rate of respiration.

[Prospects of antisense therapy technologies]

Up-to now three variants of antisense technologies are known, namely antisense oligonucleotides, RNA interference, and ribozymes. In spite of different mechanisms of action, all of them are united by the common principle: an antisense preparation works after binding with RNA-target by forming a duplex. Today all three variants are intensively used in vivo. Present posture of affairs in use of antisense technologies for treating various diseases is considered in the review.

[Preparation and in vitro and in vivo study of antisense oligodeoxynucleotides-loaded cationic liposomes]

The aim of the paper is to prepare stable antisense oligodeoxynucleotides-loaded cationic liposomes and evaluate the transfection efficiency of asODN to MCF-7 oophoroma cells and study their distribution to different tissues in mice. Antisense oligodeoxynucleotides (asODN)-loaded cationic liposomes were prepared by a thin film-adsorption-lyophilization method which is simple and can overcome crucial pharmaceutical defects (e.g. instability) of liposomes during storage. The morphology was investigated by transmission electron microscope. The size and surface charge of the liposomes were determined by laser particle analyter. The dissociated ligodeoxynucleotides were separated from the liposomes by sephadex column and the entrapment efficiency was determined by using an ultraviolet photometer. Trehalose, mannitol, and glycine were suitable for lyophilization especially trehalose. The resulting liposomes were global microcapsule in a narrow particle size with a mean diameter of 175 nm and 320 nm before and after lyophilization, and a high zeta potentials of +32 mV. The dissociated asODN were separated from the liposomes by sephadex G-50 column and the entrapment coefficient of asODN was 88.4% pre and 83.2% post-lyophilization separately for trehalose. The growth of MCF-7 oophoroma cells were inhibited in vitro obviously (P < 0.05) and transfection efficiency of asODN was 18%, 26%, 44% after 2 h, 4 h and 8 h, respectively. The formulation and method can be used to prepare stable cationic liposomes which can effectively inhibit the growth of MCF-7 oophoroma cells and obtain a high transfection efficiency. This system can improve distribution amount of asODN to tissues especially tumors in mice.

Efficient oligonucleotide-mediated degradation of nuclear noncoding RNAs in mammalian cultured cells

Recent large-scale transcriptome analyses have revealed that large numbers of noncoding RNAs (ncRNAs) are transcribed from mammalian genomes. They include small nuclear RNAs (snRNAs), small nucleolar RNAs (snoRNAs), and longer ncRNAs, many of which are localized to the nucleus, but which have remained functionally elusive. Since ncRNAs are only known to exist in mammalian species, established experimental systems, including the Xenopus oocyte system and yeast genetics, are not available for functional analysis. RNA interference (RNAi), commonly used for analysis of protein-coding genes, is effective in eliminating cytoplasmic mRNAs, but not nuclear RNAs. To circumvent this problem, we have refined the system for knockdown of nuclear ncRNAs with chemically modified chimeric antisense oligonucleotides (ASO) that were efficiently introduced into the nucleus by nucleofection. Under optimized conditions, our system appeared to degrade at least 20 different nuclear ncRNA species in multiple mammalian cell lines with high efficiency and specificity. We also confirmed that our method had greatly improved knockdown efficiency compared with that of the previously reported method in which ASOs are introduced with transfection reagents. Furthermore, we have confirmed the expected phenotypic alterations following knockdown of HBII295 snoRNA and U7 snRNA, which resulted in a loss of site-specific methylation of the artificial RNA and the appearance of abnormal polyadenylated histone mRNA species with a concomitant delay of the cell cycle S phase, respectively. In summary, we believe that our system is a powerful tool to explore the biological functions of the large number of nuclear ncRNAs with unknown function.

[Effect of signal transducer and activator of transcription 1 antisense oligodeoxynucleotides on inflammatory mediators, type I and type III collagen mRNA of rat pulmonary fibrosis]

AIM

To investigate the effect of aerosolized signal transducer and activator of transcription 1 (STAT1) antisense oligodeoxynucleotides (ASON) on the expression of inflammatory mediators in bronchoalveolar lavage fluid (BALF) and typeI and typeIII collagen mRNA of the bleomycin-induced rat pulmonary fibrosis.

METHODS

45 adult female Wistar rats were randomly divided into 3 groups: normal saline (NS) group, bleomycin (BLM) group and ASON group. BLM group and ASON group were intratracheally instilled with bleomycin (BLM) while NS group was instilled with NS. NS group and BLM group were aerosolized with NS while ASON group was aerosolized with STAT1 ASON on day 0, 2, 4 and 6 after intratracheal administration. Then each group was divided into 3 subgroups and the rats were sacrificed on day 7, 14 and 28. The concentration of IFN-gamma, TNF-alpha, TGF-beta1 and PDGF-BB in BALF was detected. The lung tissues were removed and HE and Masson staining was performed to observe the extent of alveolitis and fibrosis. The mRNA levels of typeI and typeIII collagen in the lung tissues were measured.

RESULTS

Compared with BLM group, the scores of alveolitis and fibrosis in ASON group were remarkably meliorated (P<0.05). Compared with NS group, the concentration of TNF-alpha, TGF-beta1 and PDGF-BB in BALF in BLM group was significantly increased, but it was lower in ASON group than in BLMA group (P<0.05). The concentration of IFN-gamma in BALF was lower in BLM group than in NS group (P<0.05), but it was higher in ASON group than in BLM group (P<0.05). The mRNA levels of typeI and typeIII collagen at various time points in ASON group were significantly lower than those in BLM group (P<0.05).

CONCLUSION

The aerosolized STAT1 ASON has anti-fibrosis effect, which may result from the lessened production of typeI and typeIII collagen through reducing the concentration of cytokines in BALF such as TNF-alpha, PDGF-BB and TGF-beta1 and inhibiting the decline of IFN-gamma in BALF.

The efficiency of CD40 down regulation by siRNA and antisense ODN: comparison of lipofectamine and FuGENE6

BACKGROUND

Dendritic cells (DCs) are ideal accessory cells in the field of gene therapy. Delivery of DNA and siRNA into mammalian cells is a useful technique in treating various diseases caused by single gene defects. Selective gene silencing by small interfering RNAs (siRNAs) and antisense oligodeoxynucleotides (ODN)s is an efficient method for the manipulation of cellular functions. An efficient, functional delivery system with no toxicity problems would be attractive.

OBJECTIVE

We compared two commercially available cationic lipids, Lipofectamine and FuGENE6, in the delivery of both siRNA and antisense ODNs into mice spleen-derived DCs.

METHODS

Cellular uptake was measured by the means of fluorescein-labelled non-silencing siRNA and antisense ODNs as a model system using flow cytometry. Cytotoxicity of the two delivery systems was compared with propidium iodide and annexin-V staining, and quantified with flow cytometry. The efficiency of our oligonucleotide delivery systems was compared by measuring CD40 expression by flow cytometry.

RESULTS

CD40 expression in DCs was 38%. After siRNA transfection by Lipofectamine, CD40 expression decreased to 13%, and after transfection by FuGENE6, it decreased to 18%. The difference was statistically significant. CD40 down regulation in DCs transfected with the two different antisense sequences by Lipofectamine was 21% and 23%, and down regulation after transfection by FuGENE6 was 19% and 18%, respectively. The differences were not statistically significant. The effects of siRNA and antisense ODNs were specific.

CONCLUSION

Lipofectamine was a more potent delivery system in siRNA effect, followed by FuGENE6. There was no significant difference between Lipofectamine and FuGENE6 as a delivery system of antisense ODNs.

[Down-regulation of Chk1/Chk2 gene expression increases apoptosis in irradiated HeLa cells and its mechanism]

OBJECTIVE

To explore the increasing effect of blocking Chk1 and /or Chk2 gene by Chk1 or Chk2-specific antisense oligodeoxynucleotides (AsODN) on apoptosis in HeLa cell line after irradiation and its mechanism of action.

METHODS

Asynchronized HeLa cells were exposed to (60)Co-irradiation at different dosage to activate G(2)/M checkpoint arrest. The cell cycle profiles were observed in HeLa cells after irradiation at a range of various doses and different time points by flow cytometry. In the experimental groups, Chk1/2 sODN and AsODN alone or in combination were transfected into HeLa cells, and the cells were exposed to (60)Co-irradiation at 24 h after transfection. The changes of Chk1/2 protein expression were assayed by Western blot and confocal laser scanning microscopy (Confocal), and the cell cycles, apoptosis rates and cell cycle specific apoptosis were detected by annexin V-PI labeling and flow cytometry.

RESULTS

Apoptotic response was significantly increased in the Hela cells after G(2)/M arrest and was inversed to activation of G(2)/M checkpoint. Either Chk1 or Chk2-specific AsODN consistently enhanced DNA damage-induced apoptosis by 90% approximately 120%, compared to corresponding sODN control (P < 0.05). Unexpectedly, combined use of Chk1- and Chk2-specific AsODN did not produce synergistic effect as compared to treatment with Chk1- or Chk2-specific AsODN alone (P > 0.05). While irradiated HeLa cells underwent apoptosis preferentially in G(1)-phase, apoptosis occurred in either of G(1)-, S- or G(2)/M -phase in the presence of Chk1 and/or Chk2 AsODN.

CONCLUSION

The radioresistance is mainly induced by activating the cell cycle checkpoint signal transduction pathway after irradiation, and abrogating of the key effector Chk1 and Chk2 may increase the apoptotic sensitivity to irradiation due to changes of the pattern of cell cycle specific apoptosis.

Antisense phenotypes reveal a functional expression of OsARF1, an auxin response factor, in transgenic rice

OsARF1 is the first full-length member of auxin response factor (ARF) gene family to be cloned from monocot plant. Using quantitative RT-PCR this study found that, the transcript abundance of OsARF1 was significantly higher in embryonic tissues than in vegetative tissues. To investigate the effect of OsARF1 on the phenotype of rice, a cDNA fragment of OsARF1 was inserted in inverse orientation to the 35S promoter in vector pBin438 to produce an antisense (AS) construction. The AS-OsARF1 construct was transferred into rice (Oryza sativa L. japonica) calli via Agrobacterium tumefaciens-mediated transformation. Molecular analysis of transgenic plants showed that the functional expression of OsARF1 was inhibited at mRNA level efficiently. The AS-OsARF1 plants showed extremely low growth, poor vigor, short curled leaves and tillered but were sterile. Therefore, the OsARF1 was shown to be essential for growth in vegetative organs and seed development.

[Effect of HBx antisense oligodeoxynucleotide on formation of transplanted hepatocellular carcinoma in nude mice]

OBJECTIVES

To study the inhibitory effect of HBx antisense oligodeoxynucleotide on the formation of transplanted hepatocellular carcinoma in nude mice.

METHOD

50 nude mice were randomly divided into 5 groups: 1 control group and 4 experimental groups. Log-phase Hep3B cells endogenously expressing HBX were injected subcutaneously in nude mice. From the second day, the PAGE purified AS1, AS2, AS3 and AS4 HBx antisense oligodeoxynucleotides were injected intraperitoneally into the 4 experimental groups, respectively, on alternate days for 5 times, and distilled water was injected into the control group. Growth information of subcutaneous transplantation tumor in nude mice was recorded for 30 days. Incidence rate of transplanted tumor in different groups was compared and analyzed by survival analysis. Statistics software SPSS12.0 was used to analyze the data.

RESULTS

Incidence rate of transplanted tumor was 100% in AS1, AS2, AS3 and control groups, and 90% in AS4 group (x2 = 3.995, P = 1.0). The median latency period for transplanted tumor formation was 19 days (17.48-20.52), 12 days (9.93-14.07), 11 days (9.45 to 12.55), 21 days (19.48 to 22.52), and 10 days (8.99 to 11.01) in AS1, AS2, AS3, AS4 and control group, respectively. The latency period for tumor formation was prolonged by treatment of mice with AS1 and AS4 antisense oligodeoxynucleotide (P less than 0.01).

CONCLUSION

Antisense oligodeoxynucleotide targeting to the appropriate sites of HBx gene can prolong the latency period of subcutaneously transplanted tumor in nude mice, however, the formation of transplanted tumor can not be completely blocked by limited treatment with these antisense oligos. In addition, our results suggest that peritoneal injection may be an effective way to deliver antisense oligodeoxynucleotide to living organisms.

[Effects of survivin antisense oligodeoxynucleotide on drug resistance in K562 cells]

OBJECTIVE

To study the effect of Survivin antisense oligodeoxgnucleotide (ASODN) on drug resistance and its mechanism in K562 cells.

METHODS

Cells were divided into four groups: ASODN group, SODN group, Lip group and blank group. Survivin ASODN was transfered into K562 cells by liposomal reagent. The expression of Survivin mRNA was detected by RT-PCR. The sensitivity of K562 cells to adriamycin (ADM) and daunorubicin (DAM) was detected by MTT assay, while the intracellular concentration of ADM and DAM was measured by flowcytometry.

RESULTS

Compared to control group Survivin mRNA expression in ASODN group decreased obviously. IC50(s) of ADM and ASODN+ADM were 0.5457 mg/L and 0.1933 mg/L respectively, IC50 (s) of DAM and ASODN+DAM were 0.5408 mg/L and 0.2027 mg/L respectively. Expression of Survivin mRNA decreased by 25.8% after the transfection of ASODN. Fluorescence intensity of ADM and ASODN+ADM in K562 cells were 51.64 and 89.92, Fluorescence intensity of DAM and ASODN+DAM in K562 cells were 63.71 and 88.47.

CONCLUSION

Expression of Survivin mRNA in k562 cells was down-regulated by ASODN. Survivin ASODN is able to reverse the drug resistance via inhibition of Survivin expression and inducement of apoptosis.

[The effect of antisense oligonucleoties specific to the harakiri mRNA on spontaneous and induced defects of mouse preimplantation embryo development]

The effect of antisense oligonucleotides specific to mRNA of the proapoptotic gene harakiri (Hrk) on the development of mouse SAMP1 (senescence-accelerated mouse prone) and (C57BL/6J x DBA/2J)F1 preimplantation embryos cultured in vitro was investigated. The SAMP1 mice are characterized by genetically determined decrease of fertility along with the highly frequent perturbations of embryonic development. Reproduction indices of the (C57BL/6J x DBA/2J) hybrids lie within the normal range. Because of this, preimplantation abnormalities in this line were induced by the action of proapoptotic agent bleomycine. It was demonstrated that antisense inhibition of the Hrk expression had no effect on the frequency of genetically determined abnormalities of early embryonic development in SAMP1 mice. In case of induced abnormalities, addition of oligonucleotides specific to mRNA of proapoptotic Hrk gene influenced the number of abnormalities, and at the same time, improved the quality of survived embryos via increasing the blastocyst hatching.

[Effect of nanosize delivery system for ASODN against hTERT on the expression of telomerase in the esophageal cancer EC9706 cells]

OBJECTIVE

To investigate the inhibitory effect of nanoparticle-mediated antisense oligodeoxynucleotide (ASODN) of human telomerase reverse transcriptase (hTERT) on telomerase in the esophageal cancer EC9706 cells.

METHODS

Line-polyethylenimine (L-PEI) was used to condense ASODN into nanoparticle and to couple NGR peptides into targeting nanoparticle, and the prepared L-PEI/ASODN complexes were transfected into the EC9706 cells. Cellular uptake of L-PEI/ASODN complexes was detected by laser confocal scanning microscopy. MTT assay was used to detect the inhibitory rate of EC9706 cell growth. The level of hTERT mRNA and its protein expression were measured by RT-PCR and immunohistochemistry, respectively. Annexin V FITC/PI double labeling was used to detect cell apoptosis. The distribution of drug in nude mice was observed by laser confocal scanning microscopy, and the growth and morphology of the tumor was examined.

RESULTS

The L-PEI-mediated ASODN uptake was enhanced. After transfection, the inhibitory rate of EC9706 cells was time-dependant and there was a significant difference between control cell group and L-PEI/ASODN group (P < 0.05). At 48 h after transfection, the level of hTERT mRNA was decreased significantly compared with that of control cell group (P < 0.05), and the expression of hTERT protein was negative. There was apparent apoptosis in EC9706 cells after transfection with L-PEI/ASODN complexes. For the two NGR/L-PEI/ASODN groups, fluorescence was observed in the liver, kidney, lung and tumor tissues of nude mice, and their uptake intensity was time-dependent. The mean volume of tumors in the two NGR/L-PEI/ASODN groups was significantly smaller than those in blank control group and SODN group (P < 0.05). Apoptotic bodies were detected in the tumors of L-PEI/ASODN group.

CONCLUSION

The NGR/L-PEI/ASODN nanoparticles can effectively reach into the human esophageal cancer xenograft and inhibit the tumor growth in nude mice, and this may provide a theoretical and experimental basis for gene therapy for human esophageal squamous cell carcinoma.

[Combinational effects of K-ras and IGF-IR antisense oligodeoxynucleotide on proliferation and apoptosis of human pancreatic cancer Patu8988 cells]

BACKGROUND & OBJECTIVE

Point mutation of K-ras gene and overexpression of insulin-like growth factor receptor type 1 (IGF-IR) may contribute to the progression and aggressiveness of pancreatic cancer. Antisense oligodeoxynucleotide (ASODN) against K-ras mRNA and IGF-IR mRNA may inhibit the proliferation of pancreatic cancer cells. This study was to investigate the combinational effects of K-ras ASODN and IGF-IR ASODN on proliferation and apoptosis of human pancreatic cancer Patu8988 cells in vitro and in vivo.

METHODS

K-ras gene point mutation in Patu8988 cells was detected by polymerase chain reaction using special sequence primers (PCR-SSP) and sequence analysis. According to the mutation style, K-ras ASODN was designed and composed. K-ras ASODN and IGF-IR ASODN were transfected into Patu8988 cells alone or in combination. Cell proliferation was analyzed by MTT and colony forming assay. The morphologic changes of Patu8988 cells were assessed under transmission electron microscope. The expression of K-ras and IGF-IR mRNA and protein in Patu8988 cells was measured by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry (FCM). Cell apoptosis was determined by FCM. The combinational antitumor activity of K-ras ASODN and IGF-IR ASODN was evaluated in BALB/c nude mice bearing human pancreatic cancer inoculated with Patu8988 cells.

RESULTS

The point mutation of K-ras gene at codon 12 was detected in Patu8988 cells, and the mutation style was GGT-->GTT. Either 2-32 microg/mL K-ras ASODN or IGF-IR ASODN inhibited proliferation and induced apoptosis of Patu8988 cells. This effect was more obvious when K-ras ASODN and IGF-IR ASODN were used in combination than used alone (P<0.01). In tumor-bearing mice, the inhibitory effect on the growth of transplanted pancreatic cancer was more obvious when K-ras ASODN and IGF-IR ASODN were used in combination than used alone (P<0.01).

CONCLUSION

K-ras ASODN combined with IGF-IR ASODN could cooperatively inhibit the proliferation of Patu8988 cells and induce their apoptosis via down-regulating K-ras and IGF-IR expression.

[Effect of Skp2 antisense oligodeoxynucleotide on growth and proliferation of gastric carcinoma SGC-7901 cells]

OBJECTIVE

To investigate the effect of S-phase kinase-associated protein 2 antisense oligodeoxynucleotide (Skp2 ASODN) on the growth and proliferation of gastric carcinoma SGC-7901 cells and its mechanism.

METHODS

The Skp2 oligodeoxynucleotides (ODNs) were embedded in cationic liposome Lipofectamine 2000 reagent and transfected into SGC-7901 cells. The cell growth and proliferation were observed with light microscopy and MTT assay. Cell cycle was measured by flow cytometry. The expression levels of Skp2 and p27 mRNA were detected by reverse transcription-polymerase chain reaction. The expression levels of Skp2 protein and its substrate p27 protein were detected by Western blot.

RESULT

After treatment with Skp2 ASODN, the growth and proliferation of SGC-7901 cells were inhibited in a dose-dependent manner with a peak value at 48 h. The inhibition rate of 200 nmol/L group at 48 h was 42.4 % (P<0.01). In cell cycle study the percentage of S phase cells in 200 nmol/L group was significantly higher than that in normal control group (P<0.05). Both Skp2 mRNA and its protein levels in 200 nmol/L group were significantly lower than those in control group and in Skp2 nonsense oligodeoxynucleotide (Skp2 NSODN) group (P<0.05). However, p27 mRNA level remained unchanged although its protein level was significantly higher than that in control group and NSODN group (P<0.05).

CONCLUSION

Skp2 ASODN can inhibit the growth and proliferation of SGC-7901 cells, which may be mediated by interfering with ubiquitin-proteosome pathway and cell cycle regulation.