Antisense therapy:a potential breakthrough in the treatment of neurodegenerative diseases

Neurodegenerative diseases are a group of disorders characterized by the progressive degeneration of neurons in the central or peripheral nervous system.Currently,there is no cure for neurodegenerative diseases and this means a heavy burden for patients and the health system worldwide.Therefore,it is necessary to find new therapeutic approaches,and antisense therapies offer this possibility,having the great advantage of not modifying cellular genome and potentially being safer.Many preclinical and clinical studies aim to test the safety and effectiveness of antisense therapies in the treatment of neurodegenerative diseases.The objective of this review is to summarize the recent advances in the development of these new technologies to treat the most common neurodegenerative diseases,with a focus on those antisense therapies that have already received the approval of the U.S.Food and Drug Administration.

Targeting LncRNA LLNLR-299G3.1 with antisense oligonucleotide inhibits malignancy of esophageal squamous cell carcinoma cells in vitro and in vivo

Accumulating evidence has indicated that long non-coding RNAs(lncRNAs)play critical roles in the development and progression of cancers,including esophageal squamous cell carcinoma(ESCC).However,the mechanisms of lncRNAs in ESCC are still incompletely understood and therapeutic attempts for in vivo targeting cancer-associated lncRNA remain a challenge.By RNA-sequencing analysis,we identified that LLNLR-299G3.1 was a novel ESCC-associated lncRNA.LLNLR-299G3.1 was up-regulated in ESCC tissues and cells and promoted ESCC cell proliferation and invasion.Silencing of LLNLR-299G3.1 with ASO(antisense oligonucleotide)resulted in opposite effects.Mechanistically,LLNLR-299G3.1 bound to cancerassociated RNA binding proteins and regulated the expression of cancer-related genes,including OSM,TNFRSF4,HRH3,and SSTR3.ChIRP-seq(chromatin isolation by RNA purification and sequencing)revealed that these genes contained enriched chromatin binding sites for LLNLR-299G3.1.Rescue experiments confirmed that the effects of LLNLR-299G3.1 on ESCC cell proliferation were dependent on interaction with HRH3 and TNFRSF4.Therapeutically,intravenous delivery of placental chondroitin sulfate A binding peptide-coated nanoparticles containing antisense oligonucleotide(pICSA-BP-ANPs)strongly inhibited ESCC tumor growth and significantly improved animal survival in vivo.Overall,our results suggest that LLNLR-299G3.1 promotes ESCC malignancy through regulating gene-chromatin interactions and targeting ESCC by pICSA-BP-ANPs may be an effective strategy for the treatment of lncRNA-associated ESCC.

Effect of Dexamethasone and Aquaporin-1 Antisense Oligonucleotides on the Aquaporin-1 Expression in Cultured Human Trabecular Meshwork Cells

The changes in the expression of aquaporin-1 （AQP1） mRNA and protein in cultured human trabecular meshwork （HTM） cells treated with dexamethasone and transfected with antisense oligonucleotides （AS-ODN） were studied, and the implication of AQP1 regulation in corticosteroid-glaucoma and the possibility of AS-ODN inhibiting the AQP1 expression were evaluated. The cultured HTM cells in vitro were treated with different concentrations of dexamethasone and transfected with oligonucleotides for 5 days respectively. Then, total RNA and protein of HTM cells were extracted. The changes of AQP1 mRNA and protein were demonstrated qualitatively and quantitatively by RT-PCR and Western blot. Band intensities were detected by imaging analysis. There was a parallel relationship between the results of RT-PCR and those of Western blot. The expression levels of AQP1 mRNA and protein in dexamethasone-treated groups were increased initially and decreased later as dexamethasone concentration was stepped up. In the 0.04 μg/mL and 0.4 μg/mL groups, the levels of AQP1 were higher than in control group （0 μg/mL）. In the 4 μg/ mL and 40 μg/mL groups, the AQP1 expression levels were lower than in control group. AS-ODN could down-regulate the expression of AQP1 mRNA and protein in a dose-dependent manner. At 5 μg/mL, down-regulation efficiency reached the maximum. There was no statistically significant difference in the expression of AQP1 mRNA and protein between all sense oligonucleotides groups and control group. It was suggested that dexamethasone may induce the changes of the AQP1 expression in HTM cells to be involved in the occurrence of corticosteroid-glaucoma. AS-ODN can down-regulate the AQP1 expression in HTM cells to some extent.

Enhanced therapeutic effects of combined chemotherapeutic drugs and midkine antisense oligonucleotides for hepatocellular carcinoma

AIM: To evaluate the effect of combined antisense oligonucleotides targeting midkine (MK-AS) and chemotherapeutic drugs [cisplatin(DDP), 5-fluorouracil (5-FU) and adriamycin (ADM)] on inhibition of HepG2 cell proliferation, and to analyze the efficacy of MK-AS used in combined ADM in in situ human hepatocellular carcinoma (HCC) model. METHODS: HepG2 cells were treated with MK-AS and/or chemotherapeutic drugs mediated by Lipofectin, and cell growth activity was determined by MTS assay. An in situ HCC model was used in this experiment. MK- AS, ADM and MK-AS + ADM were given intravenously for 20 d, respectively. The animal body weight and their tumor weight were measured to assess the effect of the combined therapy in vivo. RESULTS: Combined treatment with MK-AS reduced the IC50 of DDP, 5-FU and ADM in HepG2 cells. MK-AS significantly increased the inhibition rate of DDP, 5-FU and ADM. Additionally, synergism (Q 1.15) occurred at a lower concentration of ADM, 5-FU and DDP with combined MK-AS. Combined treatment with MK-AS and ADM resulted in the more growth inhibition on in situ human HCC model compared with treatment with chemotherapeutic drugs alone. CONCLUSION: MK-AS increases the chemosensitivity in HepG2 cells and in situ human HCC model, and thecombination of MK-AS and ADM has a much better in vitro and in vivo synergism.

Combination of telomerase antisense oligonucleotides simultaneously targeting hTR and hTERT produces synergism of inhibition of telomerase activity and growth in human colon cancer cell line

AIM: To investigate synergism of inhibition of telomerase activity and proliferation of human colon cancer cells by combination of telomerase antisense oligonucleotides (ASODNs) simultaneously targeting human telomerase RNA (hTR) and human telomerase reverse transcriptase (hTERT) in vitro. METHODS: ASODN of hTR and ASODN of hTERT were transfected into human colon cancer SW480 cells by liposomal transfection reagents. Telomerase activity of SW480 cells was examined using telomeric repeat amplification protocol (TRAP)-enzyme-linked immunosorbent assay (PCR-ELISA). Proliferation activity of SW480 cells was tested by methyl thiazolyl tetrazolium assay. Apoptosis and cell cycle were analyzed by flow cytometry. RESULTS: The telomerase activity and cell survival rate in SW480 cells transfected with 0.2 μmol/L of ASODN of hTR or ASODN of hTERT for 24-72 h were significantly decreased in a time-dependent manner compared with those after treatment with sense oligonucleotides and untreated (telomerase activity: 24 h, 73%, 74% vs99%, 98%; 48 h, 61%, 55% vs98%, 99%; 72 h, 41%, 37% vs 99%, 97%; P<0.01; cell survival rate: 24 h, 88%, 86% vs594%, 98%; 48 h, 49%, 47% vs94%, 97%; 72 h, 44%, 42% vs92%, 96%; P<0.01). Moreover, the telomerase activity and the cell survival rate in SW480 cells treated by the combination of telomerase anti-hTR and anti-hTERT were more significantly suppressed than single anti-hTR or anti-hTERT (telomerase activity: 24 h, 59% vs 73%, 74%; 48 h, 43% vs61%, 55%; 72 h, 18% vs41%, 37%; P<0.01; cell survival rate: 24 h, 64% vs88%, 86%; 48 h, 37% vs49%, 47%; 72 h, 25% vs44%, 42%; P<0.01). Meanwhile, the apoptosis rates in the combination group were markedly increased compared with those in the single group (24 h, 18.0% vs7.2%, 7.4%; 48 h, 23.0% vs13.0%, 14.0%; 72 h, 28.6% vs 13.2%, 13.75; P<0.01). Cells in combination group were arrested at G0/G1 phase. CONCLUSION: Telomerase anti-hRT and anti-hTERT suppress telomerase activity, and inhibit growth of human colon cancer cells probably via induction of apoptosis and retardation of cell cycle. Additionally, combined use of telomerase ASODNs targeting both hTR and hTERT yields synergistic action selective for human colon cancer.

Inhibition of PCNA Antisense Oligonucleotides Mediated by Liposome on mRNA Expression and Proliferation of h-RPE Cells

Summary： The proliferating cell nuclear antigen （PCNA） gene expression was blocked and retinal pigment epithelium （RPE） proliferation was inhibited by using antisense oligonucleotides （AS-ODN） mediated by liposome, to find a new genetic therapy of proliferative vitreoretinopathy （PVR）. RPE cells cultured in vitro were transfected with synthetic fluorescence labled AS-ODN mediated by liposome-Lipofectamine, and the intracellular distribution and persistence time of AS-ODN were dynamically observed. AS-ODN （0.07, 0.28 and 1.12 μ mol/L and sense oligonucleotides （S-ODN with the same concentrations as AS-ODN） mediated by liposome were delivered to the RPE cells cultured in vitro, and CPM values were measured by ^3H-TdR incorporation assay and analyzed statistically by variance by comparison with blank control group. Expression ofPCNA mRNA in RPE cells was detected by in situ hybridization after the treatment of different concentrations of PCNA AS-ODN and S-ODN, and the average optic density （AOD） was measured by image analysis system and was subjected to q-test and correlation analysis with CPM. Our results showed that AS-ODN mediated by liposome could quickly aggregate in cellular plasma and nuclei in 30 min and 6 h, and stayed for as long as 6 days. AS-ODN （0.28 and 1.12 μmol/L） markedly suppressed proliferation of RPE cells in a dose-dependent manner with the difference being statistically significant （P〈0.05 and P〈0.01, repectively） as compared with blank control group. AOD was well correlated with CPM （r=0.975）. It is concluded that liposome could increase transfection efficiency of AS-ODN in RPE cells, and AS-ODN could sequence-specifically suppress PCNA mRNA expression and proliferation of human RPE cells.

Inhibiting effect of antisense oligonucleotides phosphorthioate on gene expression of TIMP-1 in rat liver fibrosis

AIM: To observe the inhibition of antisense oligonucleotides (asON) phosphorthioate to the tissue inhibitors metalloproteinase-1 (TIMP-1) gene and protein expression in the liver tissue of immunologically induced hepatic fibrosis rats. The possibility of reversing hepatic fibrosis through gene therapy was observed. METHODS: Human serum albumin (HSA) was used to attack rats, as hepatic fibrosis model, in which asONs were used to block the gene and protein expressing TIMP-1. According to the analysis of modulator, structure protein, coding series of TIMP-1 genome, we designed four different asONs. These asONs were injected into the hepatic fibrosis models through coccygeal vein. The results was observed by RT-PCR for measuring TIMP-1 mRNA expression, immunohistochemistry and in situ hybridization for collagen I, II, special staining of collagen fiber, and electron microscopic examination. RESULTS: Hepatic fibrosis could last within 363 days in our modified model. The expressing level of TIMP-1 was high during hepatic fibrosis process. It has been proved by the immunohistochemical and the electron microscopic examination that the asON phosphorthioate of TIMP-1 could exactly express in vivo. The effect of colchicine was demonstrated to inhibit the expressing level of mRNA and the content of collagen I, III in the liver of experimental hepatic fibrosis rats. However, the electron microscopy research and the pathologic grading of hepatic fibrosis showed that there was no significant difference between the treatment group and the model group (P】 0.05). CONCLUSION: The experimental rat model of hepatic fibrosis is one of the preferable models to estimate the curative effect of anti-hepatic fibrosis drugs. The asON phosphorthioate of TIMP-1 could block the gene and protein expression of TIMP-1 in the liver of experimental hepatic fibrosis rats at the mRNA level. It is possible to reverse hepatic fibrosis, and it is expected to study a new drug of antihepatic fibrosis on the genetic level. Colchicine has very limited therapeutic effect on hepatic fibrosis, furthermore, its toxicity and side effects are obvious.

Obstructive Effects of Ultrasonic Microbubble Intensifier on CHG-5 Cell with Survivin Antisense Oligonucleotides Transfection

Objective： To study the effects on human glioma cell line CHG-5 by ultrasonic microbubble intensifier with survivin antisense oligonucleotides （ASODN） transfection. Methods： Antisense oligonucleotides targeting survivin mRNA was designed and synthesized. Four regimen groups were designed, group A： survivin antisense oligonucleotides transfected with ultrasonic microbubble intensifier combined with ultrasound irradiation, group B： survivin antisense oligonucleotides transfected with lipofectamine combined with ultrasound irradiation, group C： survivin antisense oligonucelotides with lipofectamine transfection, group D： blank control. The expression changes of surviving protein were measured by immunohistochemical staining and Western blotting, and MTT assay was used to measure the changes of proliferation. Results： Survivin protein expression in group A was decreased significantly in human glioma cell line CHG-5 than other groups（P〈0.05）, and the proliferating rate of CHG-5 in group A was also significantly inhibited（P〈0.05）. Conclusion： Ultrasonic microbubble intensifier transfection combined with ultrasound irradiation is a promising method in gene transfection effectively and noninvasively.

Following Inhibition of BCL-2 by Antisense Oligonucleotides Compensatory Suppression of Apoptosis Involves the Direct Signal Transduction Pathway of LNCaP Cells

Previously we have shown that when LNCaP cells are treated with antisense oligonucleotides (oligos) directed against BCL-2, compensatory changes in non-targeted genes take place in attempts to restore apoptosis and promote tumor aggressiveness. In addition to the inhibition of BCL-2, we find that the apoptosis promoter caspase-3 activity is suppressed, the transcription activity of STAT-3 is enhanced, while other regulators (bax, clusterin, AKT-1) associated with mitochondrial regulated apoptosis and caspase cascade are either unchanged or undetectable. We now evaluate proteins associated with the second pathway of apoptosis activation mediated by direct signal transduction involving fas, fas-ligand (a tumor necrosis factor-like cell surface receptor aka CD95), as well as the similar programmed death cell surface receptor (PD-1) and its respective ligand (PD-1L). This study evaluates the growth inhibition of in vitro propagating LNCaP cells employing mono- and bispecific oligos directed against BCL-2 [the second binding site was directed against the epidermal growth factor receptor (EGFR)];and employing RT-PCR. The expression of these four proteins was evaluated. Expression of fas-ligand, PD-1 and PD-L1 were all significantly enhanced, whereas fas itself was undetectable. This suggests that in addition to pathways associated with the mitochondrial pathway of apoptosis, compensatory changes occur in the direct signal transduction pathway of this process. In addition to alterations in androgen sensitivity, growth factor expression and oncogene expression, these data suggest that suppressive BCL-2 therapy involves multiple pathways, including those involved with immune targeting and cytotoxicity and must be taken into account to make gene therapy more efficacious.

SELECTION AND THEIR ANTITUMOR ACTIVITY OF ANTISENSE OLIGONUCLEOTIDES TARGETING MESSENGER RNA OF VASCULAR ENDOTHELIAL GROWTH FACTOR RECEPTOR 2

Objective： To select the antisense oligonucleotides （asONs） which hybridize with the mRNA of vascular endothelial growth factor receptor2 （VEGFR2, also named as kinase insert domain-containing receptor：KDR） in an effective and specific way, and to investigate their antitumor activity in MCF-7 cells. Methods： The effective antisense oligonucleotides were chosen by computer prediction combined with oligonucleotide microarrays. The inhibition effect on MCF-7 cells proliferation was measured by MTT; and VEGFR2 expression was surveyed by Western-blotting and RT- PCR. Results： Using predicting secondary structure of VEGFR2 mRNA with RNA folding program, computer prediction designed 30 antisense oligonucleotide probes that were directed to local loose regions of RNA structure. In 30 probes, 4（4/30, 13.33%） antisense oligonucleotides showed strong hybridization intensities in oligonucleotide microarrays test and were selected. All these antisense oligonucleotides targeting 4 different sites of VEGFR2 mRNA lowered the level of VEGFR2 mRNA and protein present in MCF-7 cells. Proliferation of MCF-7 cells was reduced by 4 antisense oligonucleotides, respectively, in which asON1 was the most effective, with the inhibitory rates being 53.06% at 0.8 I.tmol/L. Conclusion： Combination of computer prediction with oligonucleotide microarrays is an effective way in selecting optimal antisense oligonucleotides. The antisense oligonucleotides showed good correlation between their antitumor activity and the hybridization intensities. The antisense oligonucleotides targeting VEGFR2 mRNA demonstrated prominent antitumor role in vitro.

P53 Regulation of Leukemia Cells with the Blockage of MDM2 by Antisense Oligonucleotides

Summary： The changes of expression and function of MDM2 and P53 by MDM2 specific antisense oligonucleotides were investigated in HL60 cells. Cells were divided into control group, AS group （MDM2 specific antisense oligonucleotides group）, cisplatin group, and combined treatment group. FCM analysis and Western blot and RT-PCR were used to estimate apoptosis and the expression of MDM2 and P53. Our results showed that the transfection of MDM2 specific antisense oligonucleotides obviously inhibited MDM2 expression （P〈0.01） and increased the expression of P53 （P〈0.05）. Apoptosis rate were reduced by MDM2 specific antisense oligonucletides and cisplatin （P〈0.01）. It is concluded that MDM2 specific antisense oligonucletides can inhibit the expression of MDM2, induce the expression of P53 and increase the apoptosis of leukemia cells after chemotherapy.

Effects of human papillomavirus type-specific antisense oligonucleotides on the proliferation of cervical cancer cells containing papillomavirus type 16

Objective: To investigate the effects of antisense phosphorothioate oligonucleotides (S--ODNs ) on theproliferation of cervical cancer cell line SiHa, which harbor HPV16. Methods: Three different antisenseoligodeoxynucleotides were used in this study. Two of them, S--ODN1 (AE6 ) and S--ODN2 (AE7 ), arecomplementary to sequences flanking the start codons of HPV16 E6 and E7 open reading frames,respectively. SODN3 is a nonsense sequence. SiHa cells were treated with various concentrations of oligos. Growth assay and 3HTdR incorporation were used. Results: Both AE6 and AE7 markedly inhibited the proliferation and DNA synthesisof SiHa cells which harbor HPV16 but had little effects on HeLa cells that do not. S--ODN3 had none of theseeffects. Conclusion: Antisense oligodeoxynucleotides can inhibit the proliferation and DNA synthesis of HPV16positive human cervical cancer cells.

Effects of connective tissue growth factor antisense oligonucleotides on the proliferation and collagen synthesis of the cultured human keloid fibroblasts in vitro

Objective: To explore the effects of connective tissue growth factor (CTGF) on the pathogenesis of human keloid. Methods: CTGF antisense oligonucleotides (ASODN) conjugated with isothiocyananate fluorescence was encapsulated by liposome, and then added into the human keloid fibroblasts (HKFs) culture media. The intracellular distribution of CTGF ASODN was observed by fluorescence microscopy in the fixed HKFs. The proliferation of HKFs was measured by MTT test. The collagen synthesis of HKFs was measured by 3H-proline incorporation method. Results: Compared with control group, the CTGF ASODN can inhibit the proliferation and collagen synthesis of the HKFs (P<0.01). Conclusion: CTGF ASODN has anti-fibrotic effects on keloid in vitro, and CTGF play an important role in promoting the fibrosis of keloid.

Study on Apoptosis-Inducing Effect of XIAP Antisense Oligonucleotides on Glioblastoma Cells in Vitro

OBJECTIVE To investigate the apoptosis-inducing effect of XIAP antisense oligonucleotides on glioblastoma cells in vitro. METHODS There were 4 groups in our experiment. Group A, as a cell control group, had normal cell culture and no treatment applied. Group B, as a blank control group, had normal cell culture and no liposome control of ASODN. Group C was N-ODN. Group D was the ASODN group. RT-PCR and Western blot assay were conducted to detect the expression of XIAP in all A-172 ceil groups after treatment with XIAP antisense oligonucleotides （ASODN）. MTT assay and flow-cytometry （FCM） detection were used to detect the ability of cell anchoring growth and apoptotic rates of all groups. The processing time was 72 h. RESULTS The expression of XIAP in the A-172 cells was greatly down-regulated, after treated with XIAP-ASODN. Among different concentrations of ASODN, the 300nM was the most optimal one. The down-regulation of XIAP obviously inhibited the succinate dehydrogenase （SDH） activity of the A-172 cells and the increased apoptotic rate of A-172 cells （87.45%） was significantly higher than that of the A-172 in the control groups. There was a statistically significant difference between the treatment and control groups （P 〈 0.01）. CONCLUSION The XIAP-ASODN can effectively regulate the expression of the XIAP down, as a result, inhibit the growth of the glioblastoma cells （A-172） and obviously increase the apoptotic rate of the A-172 cells. The results killing role of XIAP-ASODN to the of the study manifest an overt glioblastoma cells.

Depressive Effect of the Antisense Oligonucleotides of C-myc and PCNA on the Proliferation of VSMC

Objectives To study the depressive effect of the antisense oligonuceotides （ASODN） of c-myc and proliferating cell nuclear antigen （PCNA） on the proliferation of VSMC. Methods Taking the VSMC obtained from rat aorta tho- racalis cultured 4 - 8 generation as research object. The objects were divided into three groups to carry out control study： control group, PCNA ASODN group and c-myc ASODN group. The ASODNs＇ working concentration all were 1 ： 50. The depressive effect of ASODN on VSMC proliferation was investigated by cell counting, MTT and ^3H-TdR incorporation assay; PCNA and c-myc expression were detected by immunohistochemical method after transferring PCNA and c-myc ASODN into VSMC. Results ① PCNA and c-myc ASODN could inhibit the proliferation of VSMC significantly, compared with control group （ P 〈 0. 05）. ②Transferring PCNA and c-myc ASODN into VSMC obtained successfully ; the corresponding gene was inhibited obviously ; compared with control group （ P 〈 0. 05 ）. Conclusions PCNA and c-myc might play a considerable role in the VSMC proliferation process. The corresponding gene could be depressed successfully after transferring PCNA and c-myc ASODN into VSMC, and then the proliferation of VSMC was slowed down. This study presented a beneficial proposal and theoretical fundament for atherosclerotic treatment.

Effects of antisense oligonucleotides on theexpression of macrophage migration inhibitoryfactor on macrophages

To investigate the effects of antisense oligonucleotides on the expression of macrophage migration inhibitory factor (MIF) on macrophages, the mouse phosphorothioate oligonucleotides were designed and synthesized with the sequences of antisense, 5′-TACGGATACAAGTAGCAC-3′; Sense, 5′-ATGCCTATGTTCATCGTG-3′; Missense, 5′-CTCTCAGACTCGATCTGT-3′. These phosphorothioate oligonucleotides were then transfected into cultured macrophages ( RAW264.7 ) by luciferase vector, and the transfected macrophages were incubated with Lipopolysaccharide (LPS) (1?ng/ml) for various periods of times and collected afterwards. The content of MIF protein in the cultural supernatants was determined by ELISA, cellular RNA extracted and the expression of MIF mRNA was examined by RT-PCR analysis. The experimental results showed that LPS could induce a time-dependent specific expression of MIF on macrophages, in which the MIF mRNA in cells and the MIF protein in cultural supernatants appeared after 3 h and reached their highest concentration at 9-12?h after LPS stimulation. The levels of mRNA and proteins in the macrophages treated with antisense olignucleotides were decreased significantly after stimulation with LPS in comparison with that of stimulation with LPS alone or with that with LPS plus sense or missense oligonucleotides. There were no differences among those without LPS stimulation. It is concluded that macrophages stimulated with LPS express MIF, and the antisense olignucleotides of MIF inhibit the expression of MIF mRNA as well as the secretion of MIF proteins in macrophages.

Sequencing of PCR amplified HBV DNA pre-c and c regions in 2.2.15 cells and antiviral action by targeted antisense oligonucleotide directed against sequence

AIM To study the specific inhibition of HBV gene expression by liver-targeting antisense oligonucleotide (ASON) directed against pre-c and c regious in a sequence-specific manner.METHODS According to the result of direct sequencing of PCR amplified products, a 16-mer phosphorothioate analogue of the antisense oligonucleotide (PS-ASOn) directed against the HBV U5-like region was synthesized and then linked with one live-targeting ligand, the galactosylated poly-L-lysine. Their effect on the expression of HBV gene was observed using the 2.2.15 cells.RESULTS HBV DNA in the 2.2.15 cells was from HBV with surface antigen subtype ayw1 by sequencing so that antisense oligonucleotides could bind specifically to the target sequence through base piring. Under the same experimental conditions, the inhibitory rates of PS-ASON to HBsAg and HBeAg were 70% and 58% at a concentration of 10μmol/L, while by ligand-PS-ASON they were 96% and 82%, the amount of HBV DNA in cultured supernatant and cells was reduced significantly. An unrelated sequence oligonucleotide showed no effectiveness. All the oligonucleotides had no cytotoxicity.CONCLUSION Antisense oligonucleotides complexed by the liver-targeting ligand can be targeted to cells via asialoglycoprotein receptors, resulting in supecific inhibition of HBV gene expression and replication.

Heat shock protein 70 antisense oligonucleotide inhibits cell growth and induces apoptosis in human gastric cancer cell line SGC-7901

AIM: Heat shock protein (HSP)70 is over-expressed in human gastric cancer and plays an important role in the progression of this cancer. We investigated the effects of antisense HSP70 oligomer on human gastric cancer cell line SGC-7901, and its potential role in gene therapy for this cancer.METHODS: Human gastric cancer cell line SGC-7901 was treated in vitro with various concentrations of antisense HSP70 oligonucleotides at different intervals. Growth inhibition was determined as percentage by trypan blue dye exclusion test. Extracted DNA was electrophoresed on agarose gel, and distribution of cell cycle and kinetics of apoptosis induction were analyzed by propidium iodide DNA incorporation using flow cytometry, which was also used to detect the effects of antisense oligomer pretreatment on the subsequent apoptosis induced by heat shock in SGC-7901 cells. Proteins were extracted for simultaneous measurement of HSP70 expression level by SDS-PAGE Western blotting.RESULTS: The number of viable cells decreased in a doseand time-dependent manner, and ladder-like patterns of DNA fragments were observed in SGC-7901 cells treated with antisense HSP70 oligomers at a concentration of 10 μmol/L for 48 h or 8 μmol/L for 72 h, which were consistent with inter-nucleosomal DNA fragmentation. Flow cytometric analysis showed a dose- and time-dependent increase in apoptotic rate by HSP70 antisense oligomers. This response was accompanied with a decrease in the percentage of cells in the G1 and S phases of the cell cycle, suggesting inhibition of cell proliferation. In addition, flow cytometry also showed that pretreatment of SGC-7901 cells with HSP70 antisense oligomers enhanced the subsequent apoptosis induced by heat shock treatment. Western blotting demonstrated that HSP70 antisense oligomers inhibited HSP70 expression, which preceded apoptosis, and HSP70 was undetectable at the concentration of 10 μmol/L for 48 h or 8 μmol/L for 72 h.CONCLUSION: Antisense HSP70 oligomers can abrogate HSP70 expression in SGC-7901 cells, which may in turn induce apoptosis and inhibit cell proliferation, conversely suggesting that HSP70 is required for the proliferation and survival of human gastric cancer cells under normal conditions.

Antisense oligonucleotide targeting midkine suppresses in vivo angiogenesis

AIM: To evaluate the effect of antisense oligonucleotide targeting midkine (MK-AS) on angiogenesis in chick chorioallantoic membrane (CAM) and in situ human hepatocellular carcinoma (HCC). METHODS: An in situ human hepatocellular carcinoma (HCC) model and CAM assay were used in this experiment. The effect of MK-AS on angiogenesis was evaluated by cell proliferation assay and hematoxylin- eosin (HE) staining. RESULTS: MK-AS significantly inhibited human umbilical vein endothelial cells (HUVEC) and in situ human HCC growth. At the same time, MK-AS suppressed the angiogenesis both in human hepatocellular carcinoma cell line (HEPG2)-induced CAM and in situ human HCC tissues. CONCLUSION: MK-AS is an effective antiangiogenesis agent in vivo.

Multi?targeted Antisense Oligonucleotide Delivery by a Framework Nucleic Acid for Inhibiting Biofilm Formation and Virulence

Biofilm formation is responsible for numerous chronic infections and represents a serious health challenge.Bacteria and the extracellular polysaccharides(EPS)cause biofilms to become adherent,toxic,resistant to antibiotics,and ultimately difficult to remove.Inhibition of EPS synthesis can prevent the formation of bacterial biofilms,reduce their robustness,and promote removal.Here,we have developed a framework nucleic acid delivery system with a tetrahedral configuration.It can easily access bacterial cells and functions by delivering antisense oligonucleotides that target specific genes.We designed antisense oligonucleotide sequences with multiple targets based on conserved regions of the VicK protein-binding site.Once delivered to bacterial cells,they significantly decreased EPS synthesis and biofilm thickness.Compared to existing approaches,this system is highly efficacious because it simultaneously reduces the expression of all targeted genes(gtfBCD,gbpB,ftf).We demonstrate a novel nucleic acid-based nanomaterial with multi-targeted inhibition that has great potential for the treatment of chronic infections caused by biofilms.