Oligonucleotide N3'-->P5' phosphoramidates as antisense agents

Area of Science:

• Biochemistry
• Molecular Biology
• Oligonucleotide Chemistry

Background:

• Antisense technology utilizes nucleic acid sequences to modulate gene expression.
• Development of chemically modified oligonucleotides is crucial for enhancing stability and efficacy.
• Oligonucleotide N3'-->P5' phosphoramidates represent a novel class of modified nucleic acids.

Purpose of the Study:

• To synthesize and characterize uniformly modified oligonucleotide N3'-->P5' phosphoramidates.
• To evaluate the stability of these compounds against enzymatic degradation.
• To assess their potential as antisense agents in cellular systems targeting specific oncogenes.

Main Methods:

• Synthesis of N3'-->P5' phosphoramidate oligonucleotides.
• Assessment of resistance to snake venom phosphodiesterase and HeLa cell nuclear extract.
• In vitro evaluation of antisense activity against c-myb, c-myc, and bcr-abl mRNAs in cancer cell lines.
• Quantification of protein and RNA levels using Western blot and RT-PCR.

Main Results:

• Oligonucleotide phosphoramidates demonstrated high resistance to nucleases and plasma hydrolysis.
• Antisense phosphoramidates targeting c-myb and c-myc induced significant inhibition of cancer cell proliferation and gene expression.
• Anti-c-myc and anti-bcr-abl phosphoramidates effectively inhibited primary CML cell colony formation without affecting normal bone marrow cells.

Conclusions:

• Uniformly modified oligonucleotide N3'-->P5' phosphoramidates are stable and exhibit potent sequence-specific antisense activity.
• These compounds show promise as efficient and specific therapeutic agents for cancer treatment.
• Further in vitro data support the potential utility of these phosphoramidates in antisense strategies.