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.

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.

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.

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.

A Novel Substrate for in situ Synthesis of Oligonucleotides: Hydrolyzed Microporous Polyamide-6 Membrane

A novel substrate for in situ synthesis of oligonucleotide was prepared by hydrolyzing microporous polyamide-6 membranes in a 0.01mol/L NaOH/(H2O-CH3OH) mixture medium. The formation of amines (NH2) on the surface was proved by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The treated membrane was applied for in situ synthesis of oligonucleotide and a single step coupling efficiency determined by ultraviolet (UV) spectra was above 98 %.

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.

Application of Artificially Induced Double-strand Breaks (DSB) and Triplex-forming Oligonucleotides (TFO) in the Improvement of Gene Targeting Efficiency

Gene targeting technology is an important means to investigate gene functions, but its efficiency of gene targeting is very low, especially for somatic cell targeting. Artificially induced double-strand breaks （DSB） and triplex forming oligonucleotide （TFO） are currently developed methods to improve the targeting efficiency. This paper summarized the basic principles, design ideas and application in gene targeting efficiency improvement of these two methods, analyzed and com- pared their characteristics, and finally proposed prospects for their future development.

Phosphate-Methylated Oligonucleotides Past, Present and Future

At the moment, we see a great interest for application of Anti Sense Oligonucleotides (ASOs) in order to regulate the expression of genes related to certain diseases. These nucleotides obtained a number of fascinating properties by means of chemical manipulation of natural DNA and RNA under conservation of Watson-Crick base-pairing. About 35 years ago for our research in this field, we selected synthetically (short) phosphate-methylated DNA and RNA. It was concluded that there is an exclusive selection in hybridization affinity with natural DNA and RNA. These (bio)chemical and physical-chemical properties are extensively published. ASOs have found their way in public health as is clearly shown in the treatment of (progressive) neurological diseases. We focus specifically on the past, present and future of the phosphate-methylated oligonucleotides, illustrated with different research studies in chemistry and biophysics. A new field of application of modified DNAs is based on interactive improvements of sensitivity and specificity of nanowire field effect transistor gene chip by designing phosphate-methylated DNA as probe.

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.

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.

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.

The MORC2 p.S87L mutation reduces proliferation of pluripotent stem cells derived from a patient with the spinal muscular atrophy-like phenotype by inhibiting proliferation-related signaling pathways

Mutations in the microrchidia CW-type zinc finger protein 2(MORC2)gene are the causative agent of Charcot-Marie-Tooth disease type 2Z(CMT2Z),and the hotspot mutation p.S87L is associated with a more seve re spinal muscular atrophy-like clinical phenotype.The aims of this study were to determine the mechanism of the severe phenotype caused by the MORC2 p.S87L mutation and to explore potential treatment strategies.Epithelial cells were isolated from urine samples from a spinal muscular atrophy(SMA)-like patient[MORC2 p.S87L),a CMT2Z patient[MORC2 p.Q400R),and a healthy control and induced to generate pluripotent stem cells,which were then differentiated into motor neuron precursor cells.Next-generation RNA sequencing followed by KEGG pathway enrichment analysis revealed that differentially expressed genes involved in the PI3K/Akt and MAP K/ERK signaling pathways were enriched in the p.S87L SMA-like patient group and were significantly downregulated in induced pluripotent stem cells.Reduced proliferation was observed in the induced pluripotent stem cells and motor neuron precursor cells derived from the p.S87L SMA-like patient group compared with the CMT2Z patient group and the healthy control.G0/G1 phase cell cycle arrest was observed in induced pluripotent stem cells derived from the p.S87L SMA-like patient.MORC2 p.S87Lspecific antisense oligonucleotides(p.S87L-ASO-targeting)showed significant efficacy in improving cell prolife ration and activating the PI3K/Akt and MAP K/ERK pathways in induced pluripotent stem cells.Howeve r,p.S87L-ASO-ta rgeting did not rescue prolife ration of motor neuron precursor cells.These findings suggest that downregulation of the PI3K/Akt and MAP K/ERK signaling pathways leading to reduced cell proliferation and G0/G1 phase cell cycle arrest in induced pluripotent stem cells might be the underlying mechanism of the severe p.S87L SMA-like phenotype.p.S87L-ASO-targeting treatment can alleviate disordered cell proliferation in the early stage of pluripotent stem cell induction.

New insights into the therapeutic approaches for the treatment of tauopathies

Tauopathies are a group of neurological disorders,including Alzheimer’s disease and frontotemporal dementia,which involve progressive neurodegeneration,cognitive deficits,and aberrant tau protein accumulation.The development of tauopathies cannot currently be stopped or slowed down by treatment measures.Given the significant contribution of tau burden in primary tauopathies and the strong association between pathogenic tau accumulation and cognitive deficits,there has been a lot of interest in creating therapies that can alleviate tau pathology and render neuroprotective effects.Recently,small molecules,immunotherapies,and gene therapy have been used to reduce the pathological tau burden and prevent neurodegeneration in animal models of tauopathies.However,the major pitfall of the current therapeutic approach is the difficulty of drugs and gene-targeting modalities to cross the blood-brain barrier and their unintended side effects.In this review,the current therapeutic strategies used for tauopathies including the use of oligonucleotide-based gene therapy approaches that have shown a promising result for the treatment of tauopathies and Alzheimer’s disease in preclinical animal models,have been discussed.

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.

Effect of antisense oligonucleotides targeting telomerase catalytic subunit on tumor cell proliferation in vitro

To screen specific antitumor drugs targeting telomerase catalytic subunit (hEST2), 12 different hEST2 antisense oligonucleotides were designed based on hEST2 mRNA second structure and transfected into tumor cell lines by the lipofectin-mediated method. Cell growth activity was evaluated by MTT assay. HEST212 was picked out and its specificity, antitumor tree and continuous effect were analyzed. The results showed that hEST212 had promising anti-tumor activity in vitro, hEST2 can be used as a pratical target and an antisense drug candidate for cancer.

Label-free detection of hybridization of oligonucleotides by oblique-incidence reflectivity difference method

The microarrays of 20-base oligonucleotide with different concentrations are detected before and after hybridization by the oblique-incidence reflectivity difference (OI-RD) method. The experimental results prove that OI-RD is a label-free method which can not only distinguish the concentration difference of oligonucleotides before and after the hybridization but also detect the hybridization of short oligonucleotides. At present the OI-RD method can detect 0.39 μmol/L 20-base oligonucleotide or less. These results suggest that the OI-RD method is a promising and potential technique for label-free detection of biological microarrays.

Antitumor effects of mutant endostatin are enhanced by Bcl-2 antisense oligonucleotides in UM-UC-3 bladder cancer cell line

Background Endostatin is a potent inhibitor of tumor angiogenesis. In the preliminary studies, we developed a mutant endostatin containing Arg-Gly-Asp-Arg-Gly-Asp （RGDRGD） sequences. In this study, we compared the antitumor effects of mutant endostatin and Bcl-2 antisense oligonucleotides both in combination and individually. Methods The artificially synthesized Bcl-2 ASODN （antisense oligonucleotides） included a translation-initiation site and was transfected into the bladder cancer cells by Lipofectamine. Cell growth was investigated by the tumor cell growth chart, MTT assay, caspase-3 activity detection assay, AO/EB fluorescein stain, and the annexin V-FITC apoptosis detection assay. In the in vivo study, UM-UC-3 bladder cancer cells were subcutaneously implanted into nude mice and the growth of tumor was examined. The ultrastructure of the tumor tissues in the treated and control groups were observed. Results The cell growth chart showed that the cell population of the treated combination group decreased by 52.04% compared to the control group. The inhibition rate of the treated combination group was （79.66＋6.79）%, whereas those of the individual ASODN and ES groups were （53.39＋3.22）% and （50.22＋5.46）% respectively. In the caspase-3 activity detection using AO/EB fluorescein stain and annexin V-FITC apoptosis detection assay, the co-inhibitory effect was higher than the individual inhibitory effects （P〈0.05）. There were significant differences in the inhibition of the solid tumor growth in the in vivo study. Conclusions Our findings indicated that Bcl-2 antisense oligonucleotides enhance the antitumor effects of mutant endostatin both in vitro and in vivo. We noted the synergistic effects of Bcl-2 antisense oligonucleotides combined with mutant endostatin.

Fluorescence quenching of TMR by guanosine in oligonucleotides

Nucleotide-specific fluorescence quenching in fluorescently labeled DNA has many applications in biotechnology. We have studied the inter-and intra-molecular quenching of tetramethylrhodamine (TMR) by nucleotides to better understand their quenching mechanism and influencing factors. In agreement with previous work, dGMP can effectively quench TMR, while the quenching of TMR by other nucleotides is negligible. The Stern-Volmer plot between TMR and dGMP delivers a bimolecular quenching constant of Ks=52.3 M-1. The fluorescence of TMR in labeled oligonucleotides decreases efficiently through photoinduced electron transfer by guanosine. The quenching rate constant between TMR and guanosine was measured using fluorescence correlation spectroscopy (FCS). In addition, our data show that the steric hindrance by bases around guanosine has significant effect on the G-quenching. The availability of these data should be useful in designing fluorescent oligonucleotides and understanding the G-quenching process.

Apoptosis of drug-resistant human ovarian carcinoma cell line COCl/DDP induced by survivin antisense oligonucleotides

Currently, surgery-oriented treatment plays a major role in the treatment of ovarian cancer patients. But 5-year survival rate of patients is still around 30%. One of the main reasons for the low survival rate is the drug resistance of tumor cells against chemotherapy. The function of anti- apoptosis in the course of initiation and progress of cancer has a close relationship with drug resistance of tumor cells. Survivin is a new discovered anti-apoptosis gene, its expression levels correlating with more aggressive disease and poor clinical outcome in many of these tumors. It has been reported that survivin is expressed during fetal development and in cancer tissues. Furthermore, survivin overexpression, by disrupting the balance between cell proliferation/differentiation and apoptosis, may relate with the resistance to a variety of apoptotic stimuli, including chemotherapy. We designed antisense oligonucleotides of survivin to treat the drug-resistant human ovarian carcinoma cell line COC1/DDP, and studied its effects on inducing COC1/DDP apoptosis. The purpose of this study was to find a novel approach to improve the sensitivity of ovarian carcinoma chemotherapy.