In vivo studies with antisense oligonucleotides

Potential roles of hyaluronic acid in in vivo CAR T cell reprogramming for cancer immunotherapy

Chimeric antigen receptor (CAR) T cell therapy has recently shown unprecedented clinical efficacy for cancer treatment, particularly of hematological malignancies. However, the complex manufacturing processes that involve ex vivo genetic modification of autologous T cells limits its therapeutic application. CAR T cells generated in vivo provide a valid alternative immunotherapy, "off-the-shelf", for cancer treatment. This approach requires carriers for the delivery of CAR-encoding constructs, which are plasmid DNA or messenger RNA, to T cells for CAR expression to help eradicate the tumor. As such, there are a growing number of studies reporting gene delivery systems for in vivo CAR T cell therapy based on viral vectors and polymeric nanoparticles. Hyaluronic acid (HA) is a natural biopolymer that can serve for gene delivery, because of its inherent properties of cell recognition and internalization, as well as its biodegradability, biocompatibility, and presence of functional groups for the chemical conjugation of targeting ligands. In this review, the potential of HA in the delivery of CAR constructs is discussed on the basis of previous experience of HA-based nanoparticles for gene therapy. Furthermore, current studies on CAR carriers for in vivo-generated CAR T cells are included, giving an idea of a rational design of HA-based systems for the more efficient delivery of CAR to circulating T cells.

TGF-β2 silencing to target biliary-derived liver diseases

OBJECTIVE

TGF-β2 (TGF-β, transforming growth factor beta), the less-investigated sibling of TGF-β1, is deregulated in rodent and human liver diseases. Former data from bile duct ligated and MDR2 knockout (KO) mouse models for human cholestatic liver disease suggested an involvement of TGF-β2 in biliary-derived liver diseases.

DESIGN

As we also found upregulated TGFB2 in liver tissue of patients with primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC), we now fathomed the positive prospects of targeting TGF-β2 in early stage biliary liver disease using the MDR2-KO mice. Specifically, the influence of TgfB2 silencing on the fibrotic and inflammatory niche was analysed on molecular, cellular and tissue levels.

RESULTS

TgfB2-induced expression of fibrotic genes in cholangiocytes and hepatic stellate cellswas detected. TgfB2 expression in MDR2-KO mice was blunted using TgfB2-directed antisense oligonucleotides (AON). Upon AON treatment, reduced collagen deposition, hydroxyproline content and αSMA expression as well as induced PparG expression reflected a significant reduction of fibrogenesis without adverse effects on healthy livers. Expression analyses of fibrotic and inflammatory genes revealed AON-specific regulatory effects on Ccl3, Ccl4, Ccl5, Mki67 and Notch3 expression. Further, AON treatment of MDR2-KO mice increased tissue infiltration by F4/80-positive cells including eosinophils, whereas the number of CD45-positive inflammatory cells decreased. In line, TGFB2 and CD45 expression correlated positively in PSC/PBC patients and localised in similar areas of the diseased liver tissue.

CONCLUSIONS

Taken together, our data suggest a new mechanistic explanation for amelioration of fibrogenesis by TGF-β2 silencing and provide a direct rationale for TGF-β2-directed drug development.

Nucleic acid-based therapy for coronavirus disease 2019

The coronavirus disease 2019 (COVID-19), the pandemic that originated in China has already spread into more than 190 countries, resulting in huge loss of human life and many more are at the stake of losing it; if not intervened with the best therapeutics to contain the disease. For that aspect, various scientific groups are continuously involved in the development of an effective line of treatment to control the novel coronavirus from spreading rapidly. Worldwide scientists are evaluating various biomolecules and synthetic inhibitors against COVID-19; where the nucleic acid-based molecules may be considered as potential drug candidates. These molecules have been proved potentially effective against SARS-CoV, which shares high sequence similarity with SARS-CoV-2. Recent advancements in nucleic acid-based therapeutics are helpful in targeted drug delivery, safely and effectively. The use of nucleic acid-based molecules also known to regulate the level of gene expression inside the target cells. This review mainly focuses on various nucleic acid-based biologically active molecules and their therapeutic potentials in developing vaccines for SARS-CoV-2.

Transferrin-conjugated SNALPs encapsulating 2'-O-methylated miR-34a for the treatment of multiple myeloma

Stable nucleic acid lipid vesicles (SNALPs) encapsulating miR-34a to treat multiple myeloma (MM) were developed. Wild type or completely 2'-O-methylated (OMet) MiR-34a was used in this study. Moreover, SNALPs were conjugated with transferrin (Tf) in order to target MM cells overexpressing transferrin receptors (TfRs). The type of miR-34a chemical backbone did not significantly affect the characteristics of SNALPs in terms of mean size, polydispersity index, and zeta potential, while the encapsulation of an OMet miR-34a resulted in a significant increase of miRNA encapsulation into the SNALPs. On the other hand, the chemical conjugation of SNALPs with Tf resulted in a significant decrease of the zeta potential, while size characteristics and miR-34a encapsulation into SNALPs were not significantly affected. In an experimental model of MM, all the animals treated with SNALPs encapsulating miR-34a showed a significant inhibition of the tumor growth. However, the use of SNALPs conjugated with Tf and encapsulating OMet miR-34a resulted in the highest increase of mice survival. These results may represent the proof of concept for the use of SNALPs encapsulating miR-34a for the treatment of MM.

Multi-compartmental oral delivery systems for nucleic acid therapy in the gastrointestinal tract

Gene and RNA interference therapies have significant potential for alleviating countless diseases, including many associated with the gastro-intestinal (GI) tract. Unfortunately, oral delivery of genes and small interfering RNA (siRNA) is very challenging due to the extracellular and intracellular barriers. In this review, we discuss the utilization of multi-compartmental delivery systems for oral administration of nucleic acid therapies. Some of the illustrative examples of multi-compartmental systems include solid nanoparticles-in-microsphere, solid nanoparticles-in-emulsion, and liquid nanoparticles-in-emulsion. Using type B gelatin nanoparticles encapsulated in poly(ε-caprolactone) microspheres, we have prepared nanoparticles-in-microsphere oral system (NiMOS) for gene and siRNA delivery for the treatment of inflammatory bowel disease (IBD). The results of these studies show that the multi-compartmental formulations can overcome many of the barriers for effective oral gene and siRNA delivery.

Lipid conjugated oligonucleotides: a useful strategy for delivery

Oligonucleotides, including antisense oligonucleotides and siRNA, are promising therapeutic agents against a variety of diseases. Effective delivery of these molecules is critical in view of their clinical application. Therefore, cation-based nanoplexes have been developed to improve the stability as well as the intracellular penetration of these short fragments of nucleic acids. However, this approach is clearly limited by the strong interaction with proteins after administration and by the inherent toxicity of these positively charged transfection materials. Neutral lipid-oligonucleotide conjugates have become a subject of considerable interest to improve the safe delivery of oligonucleotides. These molecules have been chemically conjugated to hydrophobic moieties such as cholesterol, squalene, or fatty acids to enhance their pharmacokinetic behavior and trans-membrane delivery. The present review gives an account of the main synthetic methods available to conjugate lipids to oligonucleotides and will discuss the pharmacological efficacy of this approach.

Involvement of spinal neurotrophin-3 in electroacupuncture analgesia and inhibition of spinal glial activation in rat model of monoarthritis

Although electroacupuncture (EA) has been proven to effectively relieve pain associated with arthritis, the underlying mechanism of EA analgesia requires further investigation. Here, the involvement of spinal neurotrophin-3 (NT-3) in EA's analgesic effects on complete Freund's adjuvant (CFA)-induced inflammatory pain was examined. The present study demonstrated that: 1) repeated EA stimulation of ipsilateral GB30 and GB34 acupoints remarkably suppressed CFA-induced hyperalgesia; 2) EA treatment markedly enhanced the upregulation of spinal NT-3 mRNA and protein levels following CFA injection; 3) antisense oligodeoxynucleotides (ODN) specifically against NT-3 intrathecally administered during EA treatment for 7 days significantly attenuated the EA analgesia; and 4) the suppressed expression of spinal GFAP (astrocytic marker), OX-42 (microglial marker) as well as proinflammatory cytokines, interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α by EA treatment was significantly attenuated following NT-3 antisense ODN delivery. These results suggested that endogenous NT-3 may be involved in the analgesic effect of EA on inflammatory pain in rats, mediated through the inhibition of spinal glial activity as well as proinflammatory cytokine production.

PERSPECTIVE

The present study may initiate a discussion on the possible roles of NT-3/glia/cytokines in the therapeutic effects of acupuncture and provide insight on the mechanism underlie the analgesic effects of acupuncture on pain associated with arthritis.

Evaluation of osteoclastogenesis via NFκB decoy/mannosylated cationic liposome-mediated inhibition of pro-inflammatory cytokine production from primary cultured macrophages

PURPOSE

To explore the effect of NFκB activation in macrophages on osteoclastogenesis of bone marrow cells for potential application as a new type of therapy for preventing bone loss.

METHODS

Primary cultured macrophages and bone marrow cells were prepared from mice. As macrophage-targeted carriers, Mannosylated cationic liposomes (Man-liposomes) were prepared and were allowed to form complexes with NFκB decoy (a double-stranded oligonucleotide). Cellular uptake, inhibition of NFκB activation, and cytokine production were evaluated using macrophages. Osteoclastogenesis was investigated using bone marrow cells, which were cultured in the conditioned medium prepared from macrophages with or without Man-liposome/NFκB decoy complexes treatment.

RESULTS

Cellular accumulation of NFκB decoy was enhanced by Man-liposome. NFκB activation in macrophages and TNF-α production were suppressed in macrophages by Man-liposome/NFκB decoy complexes but not by the naked NFκB decoy, Gal-liposome/NFκB decoy complexes, or Man-liposome/random decoy complexes. Osteoclastogenesis of bone marrow cells was induced in the conditioned medium prepared from activated macrophages but not by activated macrophages treated with Man-liposome/NFκB decoy complexes.

CONCLUSION

Osteoclastogenesis induced by activated macrophages could be suppressed by the treatment macrophages with Man-liposome/NFκB decoy complexes. Macrophage-targeted delivery of NFκB decoys using Man-liposomes may be promising in its use for the remediation of bone loss.

Cationic nanosystems for the delivery of small interfering ribonucleic acid therapeutics: a focus on toxicogenomics

IMPORTANCE OF THE FIELD

siRNAs may serve as novel nanomedicines for sequence-specific gene silencing in the clinic. However, delivering siRNA to targeted tissue or cells remains a challenge. An appropriate delivery nanosystem such as cationic polymers or liposomes is required for effective gene silencing with siRNA in vivo but the available drug delivery vectors are not all biologically inert.

AREAS COVERED IN THIS REVIEW

A combination of highly focused and comprehensive literature searches to identify any relevant reports using Medline (from 1950 to 7 April 2010) through the OVID system.

WHAT THE READER WILL GAIN

Using cationic delivery nanosystems as examples, this review article highlights the importance of undertaking toxicogenomics studies - the application of transcription profiling to toxicology - to acquire gene expression signatures of siRNA delivery systems so as to determine and/or predict their impact on gene silencing activity and specificity. Such nanotoxicological information will be important for the optimal selection of siRNA-delivery system combinations in the many proposed clinical applications of RNA interference.

TAKE HOME MESSAGE

Cationic delivery nanosystems can elicit multiple gene expression changes in cells that may contribute to the 'off-target' effects of siRNAs and/or modulate their pharmacological activity. Thus, selection of delivery systems for siRNA applications should be based on both their delivery enhancing capability and toxicogenomics.

Murine neurofibroma reversion by antisense RNA for HTLV-I tax

Neurofibroma cell lines derived from mice transgenic for HTLV-I LTR tax express high levels of HTLV-I tax mRNA and protein and exhibit a transformed phenotype. A retrovirus vector carrying HTLV-I tax cDNA in reversed transcriptional orientation was stably transfected into the neurofibroma cells. Antisense RNA inhibited expression of the tax gene with a decrease of more than 40% in both tax mRNA and protein. Tax antisense RNA reversed the transformed phenotype as exhibited by dramatic changes in cell morphology and growth characteristics. Expression of several cellular genes which are activated by Tax protein including GM-CSF, IL-6, LT/TNF, c-myc and LIF was down-regulated, while M-CSF and c-src proto-oncogene expressions were up-regulated. Accumulation of beta-actin mRNA was not affected. The changes that occurred in the tax antisense expressing neurofibroma cells could be the consequence of the decreased concentration of Tax protein. These results also indicate that HTLV-I Tax protein is crucial for maintaining the transformed cell morphology, growth and proliferation of murine neurofibroma cells and suggest that deregulation of endogenous cellular genes by Tax protein is the mechanism through which neurofibromas occur in tax mice.

Nonviral approaches for targeted delivery of plasmid DNA and oligonucleotide

Successful gene therapy depends on the development of efficient delivery systems. Although pDNA and ODN are novel candidates for nonviral gene therapy, their clinical applications are generally limited owing to their rapid degradation by nucleases in serum and rapid clearance. A great deal of effort had been devoted to developing gene delivery systems, including physical methods and carrier-mediated methods. Both methods could improve transfection efficacy and achieve high gene expression in vitro and in vivo. As for carrier-mediated delivery in vivo, since gene expression depends on the particle size, charge ratio, and interaction with blood components, these factors must be optimized. Furthermore, a lack of cell-selectivity limits the wide application to gene therapy; therefore, the use of ligand-modified carriers is a promising strategy to achieve well-controlled gene expression in target cells. In this review, we will focus on the in vivo targeted delivery of pDNA and ODN using nonviral carriers.

An efficient RNA-cleaving DNA enzyme can specifically target the 5'-untranslated region of severe acute respiratory syndrome associated coronavirus (SARS-CoV)

Background

The worldwide epidemic of severe acute respiratory syndrome (SARS) in 2003 was caused by a novel coronavirus called SARS‐CoV. We report the use of DNAzyme (catalytic DNA) to target the 5′‐untranslated region (5′UTR) of a highly conserved fragment in the SARS genome as an approach to suppression of SARS‐CoV replication. A mono‐DNA enzyme (Dz‐104) possessing the 10–23 catalytic motif was synthesized and tested both in vitro and in cell culture.

Materials and methods

SARS‐CoV total RNA was isolated, extracted from the SARS‐CoV‐WHU strain and converted into cDNA. We designed a RNA‐cleaving 10–23 DNAzyme targeting at the loop region of the 5′UTR of SARS‐CoV. The designed DNAzyme, Dz‐104, and its mutant version, Dz‐104 (mut), as a control consist of 9 + 9 arm sequences with a 10–23 catalytic core. In vitro cleavage was performed using an in vitro transcribed 5′UTR RNA substrate. A vector containing a fused 5′UTR and enhanced green fluorescent protein (eGFP) was co‐transfected with the DNAzyme into E6 cells and the cells expressing eGFP were visualized with fluorescence microscopy and analyzed by fluorescence‐activated cell sorting (FACS).

Results and conclusions

Our results demonstrated that this DNAzyme could efficiently cleave the SARS‐CoV RNA substrate in vitro and inhibit the expression of the SARS‐CoV 5′UTR‐eGFP fusion RNA in mammalian cells. This work presents a model system to rapidly screen effective DNAzymes targeting SARS and provides a basis for potential therapeutic use of DNA enzymes to combat the SARS infection. Copyright © 2007 John Wiley & Sons, Ltd.

Nonviral delivery of synthetic siRNAs in vivo

Sequence-specific gene silencing using small interfering RNA (siRNA) is a Nobel prize-winning technology that is now being evaluated in clinical trials as a potentially novel therapeutic strategy. This article provides an overview of the major pharmaceutical challenges facing siRNA therapeutics, focusing on the delivery strategies for synthetic siRNA duplexes in vivo, as this remains one of the most important issues to be resolved. This article also highlights the importance of understanding the genocompatibility/toxicogenomics of siRNA delivery reagents in terms of their impact on gene-silencing activity and specificity. Collectively, this information is essential for the selection of optimally acting siRNA delivery system combinations for the many proposed applications of RNA interference.

Antisense therapeutics for tumor treatment: the TGF-beta2 inhibitor AP 12009 in clinical development against malignant tumors

Overexpression of the cytokine transforming growth factor-beta 2 (TGF-beta2) is a hallmark of various malignant tumors including pancreatic carcinoma, malignant glioma, metastasizing melanoma, and metastatic colorectal carcinoma. This is due to the pivotal role of TGF-beta2 as it regulates key mechanisms of tumor development, namely immunosuppression, metastasis, angiogenesis, and proliferation. The antisense technology is an innovative technique offering a targeted approach for the treatment of different highly aggressive tumors and other diseases. Antisense oligonucleotides are being developed to inhibit the production of disease-causing proteins at the molecular level. The immunotherapeutic approach with the phosphorothioate oligodeoxynucleotide AP 12009 for the treatment of malignant tumors is based on the specific inhibition of TGF-beta2. After providing preclinical proof of concept, the safety and efficacy of AP 12009 were assessed in clinical phase I/II open-label dose-escalation studies in recurrent or refractory high-grade glioma patients. Median survival time after recurrence exceeded the current literature data for chemotherapy. Currently, phase I/II study in advanced pancreatic carcinoma, metastatic melanoma, and metastatic colorectal carcinoma and a phase IIb study in recurrent or refractory high-grade glioma are ongoing. The preclinical as well as the clinical results implicate targeted TGF-beta2 suppression as a promising therapeutic approach for malignant tumor therapy.

Combinatorial selection and delivery of thioaptamers

Oligonucleotide-based agents are emerging as potential therapeutic agents that can be attractive alternatives for the small-molecule chemical drugs. Monothiophosphate-backbone-modified DNA aptamers (thioaptamers) that specifically and tightly bind to the RNase H domain of the HIV RT (reverse transcriptase) have been isolated from nucleic acid libraries using combinatorial selection methods. The selected thioaptamer inhibited RNase H activity of the HIV RT in in vitro studies. In cell cultures, the transfected thioaptamer markedly reduced HIV production in a dose-dependent manner. Gel electrophoretic mobility-shift assays and NMR spectroscopy showed that the selected thioaptamer binds to the isolated RNase H domain, but did not bind to a structurally similar RNase H from Escherichia coli. In cell cultures, the transfected thioaptamer showed a dose-dependent inhibition of HIV replication, with a maximal inhibition of 83%. Using various liposome-delivery agents, the DNA thioaptamer was transfected into HIV-infected astrocytoma adherent cells with greater than 70% efficiency.

Syntheses of 4'-thioribonucleosides and thermodynamic stability and crystal structure of RNA oligomers with incorporated 4'-thiocytosine

A facile synthetic route for the 4'-thioribonucleoside building block (4'S)N (N = U, C, A and G) with the ribose O4' replaced by sulfur is presented. Conversion of l-lyxose to 1,5-di-O-acetyl-2,3-di-O-benzoyl-4-thio-d-ribofuranose was achieved via an efficient four-step synthesis with high yield. Conversion of the thiosugar into the four ribonucleoside phosphoramidite building blocks was accomplished with additional four steps in each case. Incorporation of 4'-thiocytidines into oligoribonucleotides improved the thermal stability of the corresponding duplexes by approximately 1 degrees C per modification, irrespective of whether the strand contained a single modification or a consecutive stretch of (4'S)C residues. The gain in thermodynamic stability is comparable to that observed with oligoribonucleotides containing 2'-O-methylated residues. To establish potential conformational changes in RNA as a result of the 4'-thio modification and to better understand the origins of the observed stability changes, the crystal structure of the oligonucleotide 5'-r(CC(4'S)CCGGGG) was determined and analyzed using the previously solved structure of the native RNA octamer as a reference. The two 4'-thioriboses adopt conformations that are very similar to the C3'-endo pucker observed for the corresponding sugars in the native duplex. Subtle changes in the local geometry of the modified duplex are mostly due to the larger radius of sulfur compared to oxygen or appear to be lattice-induced. The significantly increased RNA affinity of 4'-thio-modified RNA relative to RNA, and the relatively minor conformational changes caused by the modification render this nucleic acid analog an interesting candidate for in vitro and in vivo applications, including use in RNA interference (RNAi), antisense, ribozyme, decoy and aptamer technologies.

Pharmacokinetics and biodistribution of novel aptamer compositions

PURPOSE

Aptamers are highly selective nucleic acid-based drugs that are currently being developed for numerous therapeutic indications. Here, we determine plasma pharmacokinetics and tissue distribution in rat of several novel aptamer compositions, including fully 2'-O-methylated oligonucleotides and conjugates bearing high-molecular weight polyethylene glycol (PEG) polymers, cell-permeating peptides, and cholesterol.

METHODS

Levels of aptamer conjugates in biological samples were quantified radiometrically and by a hybridization-based dual probe capture assay with enzyme-linked fluorescent readout. Intact aptamer in urine was detected by capillary gel electrophoresis and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF).

RESULTS

Aptamer compositions examined exhibited a wide range of mean residence times in circulation (0.6-16 h) and significant variation in distribution levels among organs and tissues. Among the conjugates tested, in vivo properties of aptamers were altered most profoundly by conjugation with PEG groups. Complexation with a 20 kDa PEG polymer proved nearly as effective as a 40 kDa PEG polymer in preventing renal clearance of aptamers. Conjugation with 20 kDa PEG prolonged aptamer circulatory half-life, while reducing both the extent of aptamer distribution to the kidneys and the rate of urinary elimination. In contrast, the fully 2'-O-Me aptamer composition showed rapid clearance from circulation, and elimination with intact aptamer detectable in urine at 48 h post-administration.

CONCLUSIONS

We find that conjugation and chemical composition can alter fundamental aspects of aptamer residence in circulation and distribution to tissues. Though the primary effect of PEGylation was on aptamer clearance, the prolonged systemic exposure afforded by presence of the 20 kDa moiety appeared to facilitate distribution of aptamer to tissues, particularly those of highly perfused organs.

The design and exogenous delivery of siRNA for post-transcriptional gene silencing

RNA interference (RNAi) is a natural cellular process that effects post-transcriptional gene silencing in eukaryotic systems. Small interfering RNA (siRNA) molecules are the key intermediaries in this process which when exogenously administered can inhibit or "silence" the expression of any given target gene. Thus, siRNA molecules hold great promise as biological tools and as potential therapeutic agents for targeted inhibition of disease-causing genes. However, key challenges to the effective and widespread use of these polyanionic, macromolecular duplexes of RNA are their appropriate design and efficient delivery to cells in vitro and in vivo. This review highlights the current strategies used in the design of effective siRNA molecules and also summarises the main strategies being considered for the exogenous delivery of siRNA for both in vitro and in vivo applications.

Core-shell nanospheres for oligonucleotide delivery. V: adsorption/release behavior of 'stealth' nanospheres

The adsorption/release behavior of oligodeoxynucleotides (ODNs) on new PEGylated core-shell polymethylmethacrylate nanospheres is described. The outer shell consists of alkyl chains containing quaternary ammonium groups and of poly(ethylene glycol) chains, both covalently bound to the inner core. Ion pair formation between negatively charged ODN phosphate groups and positively charged groups on the nanosphere surface is the main interaction mechanism. No cellular toxicity in HL60 cells is observed at nanosphere concentrations required for biologically active ODN delivery. These results indicate that these novel cationic polymeric nanoparticles are safe and represent promising vectors for oligonucleotide delivery.

Targeted inhibition of gene expression of pancreatitis-associated proteins exacerbates the severity of acute pancreatitis in rats

BACKGROUND

Pancreatitis-associated protein (PAP) is a secretory protein not normally expressed in healthy pancreas but highly induced during acute pancreatitis. While PAP has been shown to be anti-bacterial and anti-apoptotic in vitro, its definitive biological function in vivo is not clear.

METHODS

To elucidate the function of PAP, antisense oligodeoxyribonucleotides (AS-PAP) targeting all three isoforms of PAP were administered via intrapancreatic injections (5 mg kg day, 2 days) to rats prior to induction of pancreatitis.

RESULTS

Severity of pancreatitis and cytokine gene expression in peripheral blood mononuclear cells (PBMC) were evaluated. Administration of AS-PAP, but not the scrambled oligodeoxyribonucleotide (SC-PAP) control, reduced pancreatitis-induced PAP expression by 55.2 +/- 6.4%, 44.0 +/- 8.9%, and 38.9 +/- 10.7% for PAP isoforms I, II, and III, respectively, compared to saline-treated controls (P < 0.05 for all). Inhibition of PAP expression significantly worsened pancreatitis: serum amylase activity, pancreas wet weight (reflecting edema), and serum C-reactive protein levels all increased in AS-PAP-treated animals compared to SC-PAP-treated controls (by 3.5-, 1.7-, and 1.7-fold, respectively; P < 0.05 for all). Histopathologic evaluation of pancreas revealed worsened edema, elevated leukocyte infiltration, and fat necrosis after AS-PAP treatment. Gene expressions of IL-1 microm and IL-4 were significantly higher in PBMC isolated from AS-PAP-treated rats compared to SC-PAP controls.

CONCLUSION

This is the first in vivo evidence indicating that PAP mediates significant protection against pancreatic injury. Our data suggest that PAP may exert its protective function by suppressing local pancreatic as well as systemic inflammation during acute pancreatitis.

Antisense Noggin oligodeoxynucleotide administration decreases cell proliferation in the dentate gyrus of adult rats

The dentate gyrus of the hippocampus is one of few regions in the adult mammalian brain characterized by ongoing neurogenesis. It has been demonstrated that Noggin antagonizes bone morphogenetic protein-4 (BMP4) to create a niche for subventricular zone neurogenesis. We previously demonstrated that Noggin and BMP4 showed strong expression in the proliferative subgranular layer of the dentate gyrus in adult rats. To examine the action of Noggin on cell proliferation in the dentate gyrus of adult rats, we administered antisense oligodeoxynucleotide (ASODN) to Noggin by continuous infusion into the lateral ventricle of rats. Antisense-infused rats displayed significant reduction in number of bromodeoxyuridine (BrdU) labeled cells in the dentate gyrus. This indicated that endogenous Noggin activity is important for naturally occurring cell proliferation in the dentate gyrus, and perhaps neurogenesis, and is one of the many factors involved in its regulation.

Antisense protein kinase A RI alpha-induced tumor reversion: portrait of a microarray

Antisense oligonucleotides can selectively block disease-causing genes due to the specificity of the Watson-Crick base-pairing mechanism of action. A genome-wide view of antisense technology is illustrated via protein kinase A RI alpha antisense. Complementary DNA microarray analysis of the RI alpha antisense-induced expression profile shows the up- and down-regulation of clusters of coordinately expressed genes that define the molecular portrait of a reverted tumor cell phenotype. This global view broadens the horizons of antisense technology; it advances the promise of antisense beyond a single target gene to the whole cell and the whole organism. Along with recent rapid advances in oligonucleotide technologies-including new chemical and biological understanding of more sophisticated nucleic acid drugs-oligonucleotide-based gene silencing offers not only an exquisitely specific genetic tool for exploring basic science but also an exciting possibility for treating and preventing cancer and other diseases.

Antisense targeting protein kinase A type I as a drug for integrated strategies of cancer therapy

We have studied the role of protein kinase A (PKA) and its type I isoform (PKAI) in the transduction of mitogenic signaling, apoptosis, and angiogenesis. We have contributed to the development of selective inhibitors of PKAI, including a hybrid DNA/RNA mixed backbone oligonucleotide (AS-PKAI). We, and others, have demonstrated that AS-PKAI has a cooperative antitumor effect with a selected class of cytotoxic drugs and with radiotherapy in vitro and in vivo and that these effects can also be obtained following oral adinistration. Previously, we developed a series of therapeutic models based on the pleiotropic role played by PKAI in cell proliferation, apoptosis, and angiogenesis. On the basis of our former demonstration of functional and structural interactions of PKAI and the activated epidermal growth factor receptor (EGFR), we have shown that the combined blockade of both signaling molecules by AS-PKAI and either the monoclonal antibody C225 (erbitux) or the small molecule ZD1839 (gefitinib), results in a marked cooperative antitumor effect in a variety of human tumor models. A further cooperative antitumor effect can be obtained when AS-PKAI is used in combination with both EGFR inhibitors and either cytotoxic drugs or radiotherapy. The antitumor activity is associated with inhibition of growth factors and angiogenic factors production and to induction of apoptosis. In light of the recently demonstrated role of PKAI on the bcl-2-dependent apoptotic pathway, we have recently shown a synergistic antitumor, antiangiogenic, and proapoptotic effect of AS-PKAI in combination with antisense bcl-2 (oblimersen) or with a bispecific bcl-2/bcl-xL second generation antisense. A connection between COX-2, EGFR and PKAI was established, and we demonstrated that the combination of AS-PKAI with gefitinib and a COX-2 inhibitor, all adminstered orally, can result in a potent antitumor and antiangiogenic activity. These studies support the development of AS-PKAI as a novel anticancer agent and suggest its potentially relevant role when integrated with conventional treatments and/or other signaling inhibitors in novel therapeutic strategies.

A new approach to stereospecific synthesis of P-chiral phosphorothioates. Preparation of diastereomeric dithymidyl-(3'-5') phosphorothioates

A new method for stereospecific synthesis of P-chiral phosphorothioates based on intramolecular nucleophile catalysis was developed.

Tailor-made core-shell nanospheres for antisense oligonucleotide delivery: IV. Adsorption/release behaviour

The adsorption/release behaviour of oligodeoxynucleotides (ODNs) on double functional core-shell polymethylmethacrylate nanospheres, with a narrow size distribution, is described. The outer shell consists of alkyl or glycolic chains containing permanently-charged quaternary ammonium groups. Ion pair formation between negatively-charged ODN phosphate groups and positively-charged groups, present on the nanosphere surface, is the main mechanism of interaction. The amount of adsorbed ODN depends on both the ODN concentration and the nanosphere surface charge density. An adsorption-induced swelling mechanism is proposed in which a modification of the charged diffuse layer around the nanospheres increases the ODN binding site accessibility with increasing ODN concentration. Adsorption on the nanosphere surface prevents serum degradation of the ODNs. ODN release is negligible in the presence of culture medium but occurs gradually in the presence of serum. No significant cytotoxicity of the free nanoparticles was found in PBMC and CEM cells after 24 h at ODN concentrations required for antisense activity.

An efficient oxidizing reagent for the synthesis of mixed backbone oligonucleotides via the H-phosphonate approach

The mixture of carbon tetrachloride, N-methyl morpholine (NMM), pyridine and water in acetonitrile has been exploited for the oxidation of dinucleoside H-phosphonate diesters to the corresponding phosphates. The system is found to be inert to the phosphoramidate (P-N) and the phosphorothioate (P-S) linkages and has successfully been applied to the solid phase synthesis of mixed-backbone oligonucleotides (MBOs).

Photocrosslinking in ruthenium-labelled duplex oligonucleotides

The formation of a photoadduct between a [Ru(1,4,5,8-tetraazaphenanthrene)(2)4,7-diphenylphenanthroline](2+) complex chemically attached to a synthetic oligonucleotide, and a guanine moiety in a complementary targeted single-stranded DNA molecule was studied for ten 17-mer duplexes by denaturing gel electrophoresis. This photoadduct formation leads to photocrosslinking of the two strands. The percentage quenching of luminescence of the complex by electron transfer was compared to the resulting yield of photocrosslinked product. This yield does not only depend on the ionisation potential of the guanine bases, which are electron donors, but also on other factors, such as the position of the guanine bases as compared to the site of attachment of the complex. The photocrosslinking yield is higher when the guanine moieties are towards the 3' end on the complementary strand as compared to the tethering site. Computer modelling results are in agreement with this preference for the 3' side for the photoreaction. Interestingly, the photocrosslink is not alkali labile. Moreover, a type III exonuclease enzyme is blocked at the position of photocrosslinking.

Antisense DNAs as targeted genetic medicine to treat cancer

Nucleic acid therapies represent a direct genetic approach for cancer treatment. Such an approach takes advantage of mechanisms that activate genes known to confer a growth advantage to neoplastic cells. The ability to block the expression of these genes allows exploration of normal growth regulation. Progress in antisense technology has been rapid, and the traditional antisense inhibition of gene expression is now viewed on a genomic scale. This global view has led to a new vision in antisense technology, the elimination of nonspecific and undesirable side effects, and ultimately, the generation of more effective and less toxic nucleic acid medicines. Several antisense oligonucleotides are in clinical trials, are well tolerated, and are potentially active therapeutically. Antisense oligonucleotides are promising molecular medicines for treating human cancer in the near future.

Efficient RNase H-directed cleavage of RNA promoted by antisense DNA or 2'F-ANA constructs containing acyclic nucleotide inserts

The ability of modified antisense oligonucleotides (AONs) containing acyclic interresidue units to support RNase H-promoted cleavage of complementary RNA is described. Manipulation of the backbone and sugar geometries in these conformationally labile monomers shows great benefits in the enzymatic recognition of the nucleic acid hybrids, while highlighting the importance of local strand conformation on the hydrolytic efficiency of the enzyme more conclusively. Our results demonstrate that the duplexes support remarkably high levels of enzymatic degradation when treated with human RNase HII, making them efficient mimics of the native substrates. Furthermore, interesting linker-dependent modulation of enzymatic activity is observed during in vitro assays, suggesting a potential role for this AON class in an RNase H-dependent pathway of controlling RNA expression. Additionally, the butyl-modified 2'F-ANA AONs described in this work constitute the first examples of a nucleic acid species capable of eliciting high RNase H activity while possessing a highly flexible molecular architecture at predetermined sites along the AON.

The antisense approach in amyloid light chain amyloidosis: identification of monoclonal Ig and inhibition of its production by antisense oligonucleotides in in vitro and in vivo models

Primary amyloid L chain (AL) amyloidosis is a plasma cell disorder in which depositions of AL cause progressive organ failure. The lack of effective therapies for this fatal disease prompts exploration of newer treatment avenues. We have investigated the application of antisense oligonucleotides (AS) for the inhibition of monoclonal Ig production. The monoclonal L chain was identified by using primers designed for amplifying the human lambda Ig V (Vlambda) region. We demonstrated that AS against L chain complementarity-determining regions inhibited the production of L chain in vitro. RPMI 8226 myeloma cells injected in SCID mice developed s.c. tumors. RT-PCR analysis showed Vlambda mRNA expression in the tumors. In addition, the presence of human Ig in the sera of mice given injection of RPMI 8226 cells was confirmed by ELISA. Administration of AS inhibited the expression of Vlambda mRNA in the s.c. tumors and decreased the concentration of L chain in serum. Therefore, we have shown that it is possible to determine the sequence of Vlambda mRNA and design specific complementary oligonucleotides, suggesting that treatment with Vlambda antisense could represent a rational novel approach to improve treatment outcome in AL amyloidosis.

Intracellular inhibition of hepatitis B virus S gene expression by chimeric DNA-RNA phosphorothioate minimized ribozyme

Chronic hepatitis B virus (HBV) infection is a major problem in Asia. Current therapies for chronic hepatitis B have limited efficacy. The successful use of ribozymes for intracellular inhibition of HBV gene expression was recently reported. As an alternative to ribozymes, the use of DNA-containing, phosphorothioate-modified, minimized hammerhead ribozymes (minizymes) to inhibit hepatitis B surface antigen (HBsAg) expression and viral replication was investigated. Such molecules can be synthesized and supplied exogenously. Two conserved sites within the HBsAg open reading frame (ORF) were targeted. PLC/PRF5 cells or 2.2.15 cells were treated with minizymes or antisense oligomers to assess the effects on cell viability, HBsAg expression, and viral DNA production. Treatment with the minizyme, MZPS1, resulted in >80% inhibition of HBsAg expression in PLC/PRF5 cells. MZPS1 had more inhibitory effect than the antisense oligonucletoide target at the same region, whereas the control minizyme had little effect. Another gene-specific minizyme, MZPS2, did not show any effect. Treated cells remained fully viable. Treatment of 2.2.15 cells with MZPS1 also led to decreased HBsAg expression. In addition, a 2.3-fold decrease in viral production was observed. Our data showed that minizymes can inhibit HBV gene expression and may potentially be useful for clinical therapy against chronic HBV infection.

Sequence and chemistry requirements for a novel aptameric oligonucleotide inhibitor of EGF receptor tyrosine kinase activity

We have previously identified a phosphorothioate oligonucleotide (PS-ODN) that inhibited epidermal growth factor receptor tyrosine kinase (TK) activity both in cell fractions and in intact A431 cells. Since ODN-based TK inhibitors may have anti-cancer applications and may also help understand the non-antisense mediated effects of PS-ODNs, we have further studied the sequence and chemistry requirements of the parent PS-ODN (sequence: 5'-GGA GGG TCG CAT CGC-3') as a sequence-dependent TK inhibitor. Sequence deletion and substitution studies revealed that the 5'-terminal GGA GGG hexamer sequence in the parent compound was essential for anti-TK activity in A431 cells. Site-specific substitution of any G with a T in this 5'-terminal motif within the parent compound caused a significant loss in anti-TK activity. The fully PS-modified hexameric motif alone exhibited equipotent activity as the parent 15-mer whereas phosphodiester (PO) or 2'-O-methyl-modified versions of this motif had significantly reduced anti-TK activity. Further, T substitutions within the two 5'-terminal G residues of the hexameric PS-ODN to produce a sequence, TTA GGG, representing the telomeric repeats in human chromosomes, also did not exhibit a significant anti-TK activity. Multiple repeats of the active hexameric motif in PS-ODNs resulted in more potent inhibitors of TK activity than the parent ODN. These results suggested that PS-ODNs, but not PO or 2'-O-methyl modified ODNs, containing the GGA GGG motif can exert potent anti-TK activity which may be desirable in some anti-tumor applications. Additionally, the presence of this previously unidentified motif in antisense PS-ODN constructs may contribute to their biological effects in vitro and in vivo and should be accounted for in the design of the PS-modified antisense ODNs.

Protein kinase A as target for novel integrated strategies of cancer therapy

We have studied the role of protein kinase A (PKA) in neoplastic transformation, apoptosis, and angiogenesis and its relationship with other signaling molecules, as a basis for developing novel therapeutic strategies. We demonstrated the involvement of PKA type I (PKA-I) in the transduction of mitogenic signals from different sources and demonstrated functional and structural interactions between PKA-I and the activated epidermal growth factor receptor (EGFR). We contributed to the identification and development of several selective inhibitors of PKA-I, such as 8-Cl-cAMP and a hybrid DNA/RNA antisense oligonucleotide of a novel class (AS-PKA-I) and of EGFR, including mAbC225 and ZD1839 (Iressa). All these agents have been investigated in cancer patients. We demonstrated the therapeutic potential of the combined blockade of PKA-I and EGFR, reporting a synergistic antitumor effect when their inhibitors are used in combination. We have also shown that PKA-I and EGFR inhibitors are able to cooperate with selected class of cytotoxic drugs and with ionizing radiation, causing a synergistic inhibition of tumor growth in vitro and in vivo, accompanied by inhibition of expression of growth and angiogenic factors and by suppression of vessel production. Moreover, PKA-I is implicated in a bcl-2-dependent apoptotic pathway, and we have recently reported a cooperative antitumor and proapoptotic effect of AS-PKA-I in combination with an AS-bcl-2. Finally, we have shown that AS-PKA-I also has antitumor and antiangiogenic effects following oral administration and that they can be greatly enhanced in combination with oral ZD1839 and oral taxanes.

Inhibition of proliferation of human small cell lung cancer cells expressing an autocrine system for gastrin releasing peptide by antisense oligodeoxynucleotides to gastrin releasing peptide receptor

The objectives of this study were to investigate the effect of antisense (AS) oligodeoxynucleotides (ODNs) directed against gastrin releasing peptide (GRP) receptor mRNA on proliferation of human small cell lung cancer (SCLC) NCI-H345 cells which express the autocrine system for GRP. The methods used were to expose human SCLC cell lines to antisense ODNs or sense ODNs and to measure their proliferation by spectrophotometric assay or viable cell counts. Our results demonstrated that the single or combined AS ODNs against GRP receptor inhibited proliferation of human SCLC NCI-H345 cells significantly by 37% (P<0.01), but did not inhibit proliferation of either human bronchial epithelial BEAS 2B cells or human SCLC NCI-N417 cells, neither of which express the GRP autocrine system. The sense controls did not significantly inhibit proliferation compared with no treatment controls. Specificity was also demonstrated by the observation that cells exposed to AS ODNs had a decrease in GRP receptor expression as measured by specific binding of 34% (P<0.01), and when all three AS ODNs were used, binding was decreased by 60% (P<0.03). Furthermore, AS ODNs decreased by 75% the maximum percentage of cells responding to GRP in an intracellular calcium release assay. Our conclusions are that antisense ODNs directed against a GRP receptor which is involved in an autocrine loop in human SCLC cells inhibited proliferation of these cells by their impact on reducing GRP receptor expression. Further development of means of increasing AS ODN specificity and effectiveness in human SCLC cell is warranted.

Advantages of antisense drugs for the treatment of oral diseases

For almost two decades, antisense oligonucleotides (AS-ON) have been used successfully to suppress and regulate gene expression in vitro and in vivo. They are, meanwhile, well established to serve as molecular tools for several biologic applications, from the study of single gene functions up to complex target gene validations. Based on an at least theoretically simple mode of action, the sequence-specific inhibition of mRNA functions after complex formation by Watson-Crick base pairing and presumably enzymatic degradation of the target mRNA, they obviously carry a high therapeutic potential for the treatment of human diseases. In recent years, a remarkable number of clinical trials have been initiated and performed to evaluate the therapeutic usefulness of antisense technology. However, after the successful development of the first antisense-based drug Vitravene (Isis Pharmaceutical Inc., Carlsbad, CA) in 1998, no second product has appeared on the market to date. Here, we describe substantial advantages for the development of antisense-based drugs against less severe oral diseases that represent novel but highly promising application fields of the technology.

Utilization of antisense oligonucleotides to study the role of 5-cytosine DNA methyltransferase in cellular transformation and oncogenesis

A large body of data point toward 5-cytosine DNA methyltransferase 1 (DNMT1) as a critical component of oncogenic programs. The study of the role of DNMT1 in cancer has been hindered by the lack of specific inhibitors. A different approach to study the role of DNMT1 in cancer is to use sequence-specific antisense oligonucleotides against DNMT1 mRNA. This paper discusses methods used to identify sequence-specific antisense oligonucleotides and to assess their DNA methylation inhibitory properties. Antisense oligonucleotides are applied to determine whether DNMT1 plays a causal role in specific cancer models ex vivo as well as in vivo.

Acridine-modified, clamp-forming antisense oligonucleotides synergize with cisplatin to inhibit c-Myc expression and B16-F0 tumor progression

The c-myc protooncogene plays a key role in the abnormal growth regulation of melanoma cells. We have targeted three polypurine sequences within the mouse myc mRNA with acridine-modified, clamp-forming antisense oligonucleotides (AS ODNs) in an effort to inhibit growth of murine melanoma cells. These ODNs are unique in that they hybridize to the target mRNA by both Watson-Crick and Hoogsteen hydrogen bond interactions, forming a triple-stranded structure. At a concentration of 3 microM E1C, E2C and E3C inhibit B16-F0 proliferation by 76, 66 and 78%, respectively. Both immunofluorescent staining and western blot analysis corroborate a proportional reduction in c-Myc expression by all three ODNs. There were clear distinctions in the ability of these ODNs to inhibit tumor progression in C57BL/6 mice as a function of Myc expression. There was no synergy demonstrated between ODN E1C with cisplatin (DDP), which inhibited tumor growth by 77% alone and 82% in combination. Although E2C inhibited growth by 54%, its effect was decreased to 32% with DDP, when compared with controls. E3C, on the other hand, demonstrated a synergistic effect with DDP, inhibiting growth by 72% in combination, but only by 1% as a single agent. Immunofluorescence analysis of tumors for each group revealed a concomitant reduction in c-Myc expression in tumors from mice treated with the most active clamp ODN alone (E1C) or clamp ODN + DDP (E1C/E3C + DDP). Western blot analysis confirmed this decrease in target protein expression. Our results document the growth-inhibitory activity of two myc-targeting antisense clamp ODNs; E1C, which has activity as a single agent, and E3C, which has in vivo synergy with DDP pretreatment. These data confirm the antiproliferative effects of these novel ODNs and document an interesting synergy with the chemotherapeutic agent DDP.

Co-delivery of an antisense oligonucleotide and 5-fluorouracil using sustained release poly (lactide-co-glycolide) microsphere formulations for potential combination therapy in cancer

Antisense oligonucleotides (AODNs) can selectively inhibit oncogene expression by Watson-Crick hybridisation to target mRNA and are being increasingly considered for use in combination with conventional drugs for potential anticancer therapy. Combination therapy of AODNs and cytotoxic agents using biodegradable polymeric delivery systems potentially offers several advantages including site-specific or organ-directed targeting, protection from digesting enzymes, and improved pharmacokinetics/pharmacodynamics resulting from sustained delivery of the entrapped drugs. Using a model AODN targeting the epidermal growth factor receptor (that is over-expressed in several cancers including breast and brain cancer) and the commonly used cytotoxic agent, 5-fluorouracil (5-FU), we have examined the use of poly (lactide-co-glycolide) (P(LA-GA)) microsphere formulations for co-delivery of these agents. Both agents were either co-entrapped in a single microsphere formulation or individually entrapped in two separate microsphere formulations and release profiles determined in vitro. Using a double emulsion method for preparing the P(LA-GA) microspheres suitable entrapment and sustained release over 35 days was observed in both types of formulation. Release of AODN and 5-FU from all formulations appeared to be biphasic. However, the release rates of the two agents were significantly slower when co-entrapped as a single microsphere formulation compared to those obtained with the separate formulations. Electrophoretic mobility shift assays suggested that this might be, in part, due to an interaction of 5-FU with the oligodeoxynucleotide (ODN). Further, our data suggest that by mixing individual formulations of 5-FU and ODNs at different mass ratios allowed greater flexibility in achieving the desired release profile as well as avoiding potential drug-drug interactions. Thus, co-administration of individual P(LA-GA) microsphere formulations of AODNs and 5-FU, at appropriate mass ratios, appears worthy of further investigation for the potential co-delivery of these anti-cancer agents in vivo.

Nucleic acid biotechnology

Driven by advances in the acquisition of genetic sequence information and the ability to manipulate small quantities of nucleic acid, a number of technologies are emerging that exploit nucleic acids for research, diagnostic, and therapeutic utility. In this review, we cover three technologies based on nucleic acids--DNA microarrays, antisense technology, and gene therapy--that are especially promising and may make a substantial impact in the laboratory and in the clinic during the coming years. For each of these areas, an overview of the current status and applications is provided, followed by a discussion of critical issues and challenges to be faced for further advancement of the technology; an emphasis is placed on quantitative and engineering aspects.

Thermal stress-induced HSP70 mediates protection against intrapancreatic trypsinogen activation and acute pancreatitis in rats

BACKGROUND & AIMS

Prior thermal stress induces heat shock protein 70 (HSP70) expression in the pancreas and protects against secretagogue-induced pancreatitis, but it is not clear that this thermal stress-induced protection is actually mediated by HSP70 since thermal stress may have other, non-HSP related, effects.

METHODS

In the present study, we have administered antisense (AS) oligonucleotides, which prevent pancreatic expression of HSP70 to rats, in vivo, to evaluate this issue. In a separate series of experiments, designed to examine the role of pancreatitis-induced HSP70 expression in modulating the severity of pancreatitis, rats not subjected to prior thermal stress were given AS-HSP70 before cerulein administration, and trypsinogen activation as well as the severity of pancreatitis were evaluated.

RESULTS

Hyperthermia induced HSP70 expression, prevented intrapancreatic trypsinogen activation, and protected against cerulein-induced pancreatitis. Administration of AS-HSP70 but not sense-HSP70 reduced the thermal stress-induced HSP70 expression, restored the ability of supramaximal cerulein stimulation to cause intrapancreatic trypsinogen activation, and abolished the protective effect of prior thermal stress against pancreatitis. In non-thermally stressed animals, pretreatment with AS-HSP70 before the induction of pancreatitis exacerbated all the parameters associated with pancreatitis.

CONCLUSIONS

These findings lead us to conclude that HSP70 induction, rather than some other thermal stress-related phenomenon, mediates the thermal stress-induced protection against pancreatitis and that it protects against pancreatitis by preventing intrapancreatic activation of trypsinogen. The worsening of pancreatitis, which occurs when non-thermally stressed animals are given AS-HSP70 before cerulein, suggests that cerulein-induced HSP70 expression in nontreated animals acts to limit the severity of pancreatitis.

Estrogen receptor-alpha antisense decreases brain estrogen receptor levels and affects ventilation in male and female rats

We hypothesized that administration of an antisense oligodeoxynucleotide (ODN) to estrogen receptor (ER)-alpha mRNA decreases the ER protein in the neonatal rat brain, alters the sex-specific ventilatory responses to aspartic acid in rats, and counteracts the effects of testosterone proportionate (TP) in females. One-day-old rat pups were injected intraventricularly with vehicle, antisense ER ODN, or scrambled ODN control. Additional groups of females received TP or vehicle and one of the three treatments. Brain ER protein levels were decreased by 65% at 6 h and 35% at 24 h after antisense ODN. Aspartic acid decreased ventilation in all groups of weanling males and females except ER ODN-treated females and TP-vehicle-treated females. Aspartic acid decreased ventilation in all groups of adult females except those given TP and in males. Weanling ER ODN-treated rats were shorter and weighed less than controls. Only adult ER ODN-treated males exhibited these traits. Thus neonatal ER affects aspartic acid modulation of breathing and body growth in a sex-specific and developmental manner.

Delivery of cholesteryl-conjugated phosphorothioate oligodeoxynucleotides to Kupffer cells by lactosylated low-density lipoprotein

The efficacy of antisense oligonucleotides depends on the ability to reach in vivo their target cells. We aim to develop strategies to enhance uptake of phosphorothioate oligodeoxynucleotides by Kupffer cells. To this end, we conjugated cholesterol to ISIS-3082, a phosphorothioate oligodeoxynucleotide specific for intercellular adhesion molecule-1. The cholesterol-conjugated oligonucleotide, denoted ISIS-9388, associated readily with lactosylated low-density lipoprotein (LacLDL), a lipidic carrier that is taken up by galactose receptors on Kupffer cells. Association of up to 10 molecules of ISIS-9388 per LacLDL particle did not induce aggregation. LacLDL-associated [3H]ISIS-9388 was rapidly taken up by the liver after injection into rats (52.9+/-1.8% of the dose within 2 min versus 18.6+/-2.8% for ISIS-3082). N-acetylgalactosamine inhibited hepatic uptake, indicating involvement of galactose-specific receptors. Liver cells were isolated at 60 min after injection of LacLDL-associated [3H]ISIS-9388. Kupffer cells displayed the highest uptake: 88.1+/-24.7 ng of oligonucleotide/mg of cell protein, which is 6-14 times higher than after injection of free ISIS-9388 or ISIS-3082 (15.0+/-3.8 ng and 6.3+/-1.4 ng, respectively). It can be calculated that Kupffer cells contribute 43.9+/-5.4% to the liver uptake (free ISIS-9388 and ISIS-3083 14.5+/-3.1% and 8.3+/-3.2%, respectively). In conclusion, conjugation of a phosphorothioate oligodeoxynucleotide with cholesterol and its subsequent association with LacLDL results in a substantially increased Kupffer cell uptake of the oligonucleotide. As Kupffer cells play a key role in inflammation, our approach may be utilized to improve antisense-based therapeutic intervention during inflammation.

Site-specific administration of antisense oligonucleotides using biodegradable polymer microspheres provides sustained delivery and improved subcellular biodistribution in the neostriatum of the rat brain

Antisense oligonucleotides (ODNs) are being increasingly used in the central nervous system as biological tools, as drug-target validation agents and as potential therapeutic agents. Although the local delivery of naked ODNs to the brain can result in the desired biological effects, the duration of efficacy is relatively short lived due to the combined effects of rapid ODN degradation and elimination half-lives in vivo. In this study, we have examined the use of biodegradable polymer microspheres as a site-specific delivery system for targeting ODNs to the neostriatum of the rat brain. Model phosphorothioate backbone-modified ODNs were entrapped within poly(D,L-lactide-co-glycolide) (PLAGA) microspheres using a double emulsion-deposition method and the formulations characterised in terms of particle size, surface morphology, percent encapsulation efficiency, ODN loading and in vitro release profiles. For in vivo evaluation, PLAGA microspheres containing fluorescently-labelled ODNs were stereo-taxically administered to the neostriatum of the rat brain and biodistribution of ODNs monitored after 48 h. Administration of free fluorescently-labelled ODNs to the neostriatum resulted in a punctate cellular distribution of ODNs after 24 h with little or no ODN remaining in the neostriatum after 48 h. In comparison, fluorescently-labelled ODNs delivered using polymer microspheres were intensely visible in cells after 48 h post-administration and the fluorescence appeared to be diffuse covering both cytosolic and nuclear regions. Dual-label immunohistochemical analyses suggested that ODNs were mainly distributed to neuronal cells. These data indicate that site-specific administration of ODNs using biodegradable polymer microspheres will not only provide sustained delivery of nucleic acids but can also improve the cellular distribution of ODNs to brain cells. Sustained or controlled-release biodegradable polymer formulations, therefore, represent an attractive strategy for improved local delivery of ODNs to the CNS.

Encapsulation of c-myc antisense oligodeoxynucleotides in lipid particles improves antitumoral efficacy in vivo in a human melanoma line

Phosphorothioate c-myc antisense oligodeoxynucleotides [S]ODNs (free INX-6295) were encapsulated in a new liposome formulation and the antitumor activity was compared to the unencapsulated antisense in a human melanoma xenograft. The systemic administration of INX-6295 encapsulated in stabilized antisense lipid particles (SALP INX-6295) improved plasma AUC (area under the plasma concentration-time curve) and initial half-life of free INX-6295, resulting in a significant enhancement in tumor accumulation and improvement in tumor distribution of antisense oligodeoxynucleotides. Animals treated with SALP INX-6295 exhibited a prolonged reduction of c-myc expression, reduced tumor growth and increased mice survival. When administered in combination with cisplatin (DDP), SALP INX-6295 produced a complete tumor regression in approximately 30% of treated mice, which persisted for at least 60 days following the first cycle of treatment. Finally, the median survival of mice treated with DDP/SALP INX-6295 increased by 105% compared to 84% for animals treated with the combination DDP/free INX-6295. These data indicate that the biological activity and the therapeutic efficacy of c-myc antisense therapy may be improved when these agents are administered in lipid-based delivery systems.

Use of antisense oligonucleotides to verify the role of the alpha(1A)-adrenergic receptor in the contractility of the rat uterus post partum

The adrenergic system plays a major role in the regulation of the contractility of the uterus during pregnancy. This study investigated the role of the alpha(1A)-adrenergic receptor (AR) in this regulation. The use of partial phosphorothioate antisense oligodeoxynucleotides (AONs) permitted the sequence-selective inhibition of AR gene expression. AONs were injected together with a cationic liposomal carrier agent into the post partum rat uterus. Incubation for 12 or 24 h with the most effective AON (480-AON) caused a 58.7 or 53.0% inhibition, respectively, of the expression of the alpha(1A)-AR density, whereas incubation for 36 or 48 h resulted in only a 38.8 or 26.7% inhibition, respectively. The decrease of the alpha(1A)-AR density by 480-AON was demonstrated by Western blot analysis and a radioreceptor binding assay on rat uterus preparations 24 h after delivery. The changes in the contractility of the uterus after AON treatment were measured on isolated rat uterine tissue by electric field stimulation. The significant decrease in the ability of the uterus to contract was indicated by the area under the curve method. The electric field studies revealed that the specific alpha(1A)-blockers 5-methylurapidil and WB 4101 inhibited the rhythmic contraction by about 74 and 70% in the control uteri and by 25 and 20% in 480-AON-treated uteri, respectively. The curves for the beta-mimetic (terbutaline) and alpha(1D)-antagonist (BMY7370) inhibitors were unchanged after 480-AON treatment of the uteri. These results suggest the importance of the alpha(1A)-AR in the tocolytic effect exerted by the alpha(1)-antagonist, although high concentrations of antagonists can not exclude the role of alpha(1D)-ARs, too. Additionally, these prove that the knockdown transformation by AONs offers a useful animal model for the investigation of receptors controlling the function of uterine tissue.