Maternal and fetal distribution of a phosphorothioate oligonucleotide in rats after intravenous infusion

BACKGROUND: Fetal uptake of an antisense oligonucleotide was evaluated after intravenous (i.v.) dosing of ISIS 2105, a 20-base phosphorothioate oligonucleotide, in timed-pregnant Sprague-Dawley rats. METHODS: To maximize the potential for fetal exposure, ISIS 2105 was administered as a 3-hr infusion at 6.6 mg/kg/hr with a total dose of 20 mg/kg, or as a continuous 7-day infusion at 0.35 mg/kg/hr with a total dose of 59 mg/kg. This dosing regime is higher than a patient would be expected to receive in the clinical use of oligonucleotides. Infusions were delivered through a jugular vein cannula by syringe pump on gestation day (GD) 19 (3-hr exposure) or by osmotic pumps implanted subcutaneously (s.c.) starting on GD 12 (7-day exposures). RESULTS: After a 3-hr infusion, maternal and fetal plasma concentrations of ISIS 2105 were >100 microg/ml and <0.07 microg/ml, respectively with a maternal fetal ratio of >1,000. Maternal regions of the placenta had twice the oligonucleotide concentration compared to fetal regions of the placenta (6 microg/g vs. 3 microg/g). After this acute exposure the concentrations in fetal kidney and liver were approximately 140- and 500-fold less than the maternal kidney and liver respectively. After 7-day infusion maternal plasma concentrations were 0.82 microg/ml and fetal concentrations were <0.22 microg/ml. By capillary gel electrophoresis (CGE) only the fetal liver consistently had quantifiable oligonucleotide concentrations (range=1.01-4.95 microg/g) compared to a mean concentration of 50.11+/-1.71 microg/g in the maternal liver a maternal to fetal ratio of approximately 10:50 after 7 days of infusion. CONCLUSIONS: There was a low level of transfer from dam to fetus, consistent with a slow equilibrium but the permeability of placenta to this 6 kDa polyanionic compound seemed to be limited even at supraclinical doses.     

Antisense Knockdown of PKC-α Using LNA-Oligos

Abstract

Full-length and 4 nucleotides truncated Locked Nucleic Acid (LNA) modifications of ISIS 3521 were compared for antisense properties in a cellular assay. ISIS 3521 is a 20-mer phosphorothioate designed to hybridise to human protein kinase C-α (PKC-α) mRNA and is currently submitted to clinical trials against cancer. We report that LNA can potentate this antisense oligo and retain the antisense potential with shorter oligos.     

Cholesterol Conjugated Uniform and Gapmer Phosphorothioate Oligonucleotides Targeted Against PKC-α and C-raf Gene Expression

Abstract

In vitra and in vivo antitumor activity of phosphorothioate antisense oligonucleotides targeted against two protein kinases within the mitogen-activated protein (MAP) kinase signaling cascade has been well documented by ISIS 3521/CGP 6412XA (targeted against PKC-α protein) and ISIS 5132KGP69846A (targeted against C-rwfl kinase). For both of these compounds, cationic lipid formulations are necessary to observe any pharmacological activity in cell culture. In contrast, in vivo functional delivery of phosphorothioate oligonucleotides to cells in tissues does not appear to be a prohlem. These oligonucleotides have demonstrated reduction in either PKC-α or C-raf gene expression in tissues or human tumor xenografts following systemic administration.     

Heterogeneity of biologically active deadenylated protamine mRNA components isolated from rainbow trout testes.

Poly(A)+ protamine mRNA's were isolated from rainbow trout testes and deadenylated by treatment with calf thymus RNase H. Four subcomponents of deadenylated PmRNA (PmRNA1-4) were purified by electrophoresis on a 6% polyacrylamide gel in 8 M urea. Translation of each PmRNA subcomponent in the wheat germ S-30 cell-free system showed that all subcomponents are biologically active but each codes for two or more protamine polypeptides suggesting molecular heterogeneity. However, the deadenylated mRNA's can be categorized into two groups based on the spectrum of protamines whose synthesis they stimulate.     

Oligonucleotide therapy

Rapid progress in oligonucleotide therapeutics has continued over the past year as major programs established in the past four years have grown and begun to be productive. Important advances were reported in the medicinal chemistry of oligonucleotides and in understanding their pharmacodynamic properties. Significant progress was made in understanding the pharmacokinetic and toxicologic properties of first generation analogs, particularly phosphorothioates and one oligonucleotide, ISIS 2105, entered clinical trials. Additionally, combinatorial approaches designed to identify oligonucleotides that may bind to a variety of targets were reported.     

Solution Phase Synthesis of Dithymidine Phosphorodithioate Using New S-Protecting Groups in Combination with a Chemoselective Coupling Reagent (PyNOP)

Abstract

ABSTRACT

A method for the synthesis of O-thymidin-3′-yl S-alkyl dithiophosphate monomers 1 with different S-protecting groups has been developed. These have been used for solution phase synthesis of dithymidine phosphorodithioate by a new phosphotriester method. Coupling reactions are fast (15 min.) and the products are free from phosphorothioate contaminations.     

Embryo Deadenylation Element-Dependent Deadenylation Is Enhanced by a cis Element Containing AUU Repeats

The deadenylation of maternal mRNAs in the Xenopus embryo is a sequence-specific process. One cis element that targets maternal mRNAs for deadenylation after fertilization is the embryo deadenylation element (EDEN). This element, composed of U/R repeats, is specifically bound by a protein, EDEN-BP. In the present study we show that the rate at which an RNA containing an EDEN is deadenylated can be increased by the presence of an additional cis element composed of three AUU repeats. This effect was observed for a natural EDEN (c-mos) and two synthetic EDENs. Hence, the enhancement of EDEN-dependent deadenylation conferred by the (AUU)₃ motif is not due to an interaction with a particular EDEN sequence. Mutation of the (AUU)₃ motif abrogated the enhancement of EDEN-dependent deadenylation. These data indicate that the rate at which a specific maternal mRNA is deadenylated in Xenopus embryos is probably defined by a cross talk between multiple cis elements.     

Base-Labile Group Protected Biotinphosphoramidite Reagents for Solid Phase Biotinylation of Oligonucleotides

Abstract

A general and rapid method is described for the synthesis of N¹ -base labile group protected biotinphosphoramidite reagents, useful for the synthesis of biotinylated oligonucleotides in automated DNA synthesizer.     

Changes in state of adenylation and time course of degradation of maternal mRNAs during oocyte maturation and early embryonic development in the mouse

Previous work has shown that more than 50% or about 50 pg of polyadenylated RNA found in the full-grown mouse oocyte is deadenylated or degraded during meiotic maturation. Here we show that rRNA declines by 60 pg during this period, accounting for most of the 80-pg decline in total RNA and indicating that a significant amount of mRNA is deadenylated but not degraded during maturation. Actin mRNA is deadenylated at about 7 hr of in vitro maturation, following the decline in its translation. The poly(A) tail on hypoxanthine phosphoribosyltransferase (HPRT) mRNA is elongated at 7 hr of maturation, preceding an increase in HPRT activity. Actin mRNA is partially degraded in the one-cell embryo and falls to near the limit of detection in the late two-cell stage, while HPRT mRNA shows no change in early two-cell embryos, but is deadenylated and declines greatly during the two-cell stage. In aging unfertilized eggs, most of these changes occur on a delayed schedule. The various species of alpha-tubulin mRNA are largely deadenylated and more than half are degraded during maturation. Taken together with other published results, we conclude that each mRNA has its own pattern of changes in the length of the poly(A) tail (correlated with translation) and degradation during the period of maternal control of protein synthesis, and, for those examined, the maternal mRNAs remaining in the early two-cell embryo are degraded to low levels by the late two-cell stage.     

ISIS database: An evaluation of records essential for captive management

Species databases are essential for the scientific management of species and specimens in captive wildlife populations. Population managers in North America base their decisions on information in two databases:the International Species Information System (ISIS) and American Zoo and Aquarium Association (AZA) approved regional studbooks. Genetic and demographic management of species relies on studbooks, whereas regional collection planning and management by Taxon Advisory Groups (TAGs) may use a combination of studbooks, direct surveys, and data from ISIS. Use of ISIS data as the primary basis for population management and collection planning is increasing, yet there has been no assessment of how ISIS data differ from studbooks. Thus these databases were compared to determine if they are interchangeable for the purposes of regional collection planning or species management. Population sizes of living individuals in 68 SSP^© taxa were compared to assess the magnitude of differences between the databases. Differences in population size were considerable and highly variable; ISIS on average underestimated the number of living animals in SSP^© taxa populations. Ten studbooks were also analyzed in detail to identify specific types of discrepancies between the two databases. On average, 19.2 ± 2.2% of the information in the ISIS database differed from that in the studbook. Most discrepancies derived from data that were either missing from, or incorrect in, the ISIS database. The most common discrepancies involve parents who were either unidentified or misidentified in the ISIS database (x? = 37.5 ± 5.7% of all records). No single type of discrepancy, however, was prevalent across all 10 species; the overall rate of discrepancies per species was attributable to a combination of discrepancies peculiar to each species. Protocols concerning data entry standards, data collection, and the scope of data collected are likely causes of most discrepancies. In its present form, the ISIS database is not appropriate for single species management; if used cautiously, it can be of assistance in the development of regional collection plans. Development of an ISIS database that is suitable for population management will require an increased commitment to data quality by records keepers, zoological institutions, and ISIS. © 1995 Wiley-Liss, Inc.     

A Convenient and Efficient Method for the Synthesis of Nucleoside H-Phosphonates Using a Novel Phosphonylating Agent

Abstract

In the present paper we describe the preparation of a novel crystalline phosphonylating agent 9-fluorenemethyl phosphonic acid 2 and a convenient and efficient method for the synthesis of nucleoside H-phosphonates 5.     

Express Protocol for Functionalization of Polymer Supports for Oligonucleotide Synthesis

Abstract

A rapid and general one-pot method is described for the attachment of the leader nucleoside onto the polymer supports, suitable for polymer supported oligonucleotide synthesis following oxidation-reduction condensation. The method can also be used for support functionalisation in fully automated DNA synthesizer prior to oligonucleotide synthesis.     

The H-Phosphonate Method for Constructing Phosphodiester Linkages. A Progress Report

Abstract

Ongoing research into the potential of the H-phosphonate method for synthesising oligonucleotides is discussed. Examples include the synthesis of an artificial Haemophilus influenzae antigen and also efforts to extend the method into the automated solid support synthesis of long RNA oligomers.     

INTRACELLULAR Ca2+-MOBILIZING ADENINE NUCLEOTIDES. SYNTHESIS AND BIOLOGICAL ACTIVITY OF CYCLIC ADP-CARBOCYCLIC-RIBOSE AND C-GLYCOSIDIC ANALOG OF ADENOPHOSTIN A

We designed novel Ca²⁺-mobilizing purine nucleotides, cyclic ADP-carbocycl-icribose 4, and its inosine congener 5, and C-glycosidic adenophostin A 6. In the synthesis of cADPR analogs, the intramolecular condensation to form the pyrophosphate linkage should be the key step. We developed an efficient method for forming such an intramolecular pyrophosphate linkage by the activation of the phenylthiophosphate group with I₂ or AgNO₃. Using this method, we achieved to synthesize the target compounds 4 and 5. The synthesis of C-glycosidic analog 6 of adenophostin A was achieved using a temporary silicon-tethered radical coupling reaction for constructing (3′α, 1″α)-C-glycosi-dic structure as the key step.     

MICROWAVE ASSISTED HIGH YIELDING PREPARATION OF N-PROTECTED 2′-DEOXYRIBONUCLEOSIDES USEFUL FOR OLIGONUCLEOTIDE SYNTHESIS

ABSTRACT

A rapid and high yielding method for the synthesis of precursors of synthons for DNA synthesis, N-protected 2′-deoxyribonucleosides is described, which occur under mild conditions using microwave irradiation. The desired material, N-protected nucleosides, was obtained in 93–96% yield in few minutes. The final products were then characterized by ¹H-NMR and MALDI-TOF and compared with the standard samples. The method is amenable to small to moderate scale of synthesis.     

A General Synthetic Method for 2′,3′-Dideoxynucleosldes: Total Synthetic Approach

Abstract

A general method for the total synthesis of 2′,3′dideoxynucleosides is described.     

Oligonucleotide Phosphonates—Solid Phase Synthesis and Biochemical Characterization

Abstract

A novel method for the automated synthesis of oligonucleotide-3′-phosphonates is described. Oligonucleotide analogs synthesized by this method exhibited appreciable stability to exonuclease digestion.     

A Rapid Solid Phase Method for the Synthesis of 3′-Thiol Group Containing Oligonucleotides

Abstract

A rapid solid phase method for the synthesis of 3′-thiol group containing oligonucleotides is described.     

A New Solid Phase Method for the Synthesis of Oligonucleotides with Terminal -3′-Phosphate

Abstract

A novel method for the synthesis of oligonucleotides with terminal-3′-phosphate using universal CPG polymer support is described.