[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.