Evaluation of adjuvants that enhance the effectiveness of antisense oligodeoxynucleotides.
OBJECTIVE
A factor limiting the effectiveness of antisense (AS) deoxyoligonucleotides (ODNs) is inefficient transport to their sites of action in the cytoplasm and in the nucleus. The extent of ODN transfer from endosomes to cytosol seems to be an important determinant of ODN effects. Consequently, the development of compounds (adjuvants) that enhance endosome to cytosol transfer may be vital in AS ODN therapeutics.


METHODS
In this report, we evaluated compounds for their potential to enhance the effects of phosphorothioate ODNs. The test system used a CHO cell line expressing the enzyme chloramphenicol acetyl-transferase (CAT) under the control of an inducible promoter. Several potential endosomal disrupting adjuvants were screened, including: (a) fusogenic peptides; (b) a pH sensitive polymer; (c) polymeric dendrimers, (d) cationic liposomes and (e) a pH sensitive surfactant N-dodecyl 2-imidazole-propionate (DIP). ODN effects were evaluated at the protein level by quantitating levels of CAT.


RESULTS
The use of AS ODN in co-incubation with the GALA peptide, cationic liposomes or 5th generation dendrimers resulted in a 35-40% reduction in CAT expression. The mis-matched ODN had no effect on CAT expression. Only modest effects were observed with the other adjuvants. DIP did not increase ODN activity by itself; however, when the liposomal form was used a significant reduction (48%) in CAT activity was seen.


CONCLUSIONS
We found the fusogenic peptide GALA, dendrimers, as well as the liposomal form of DIP, could significantly enhance the effects of ODNs.
Hughes
J A
JA
School of Pharmacy, Department of Pharmaceutics, University of Florida, Gainesville 32610, USA.
Aronsohn
A I
AI
Avrutskaya
A V
AV
Juliano
R L
RL
D000277:Adjuvants, Pharmaceutic / Q000138:chemical synthesis / Q000494:pharmacology* / Q000633:toxicity; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells / Q000187:drug effects / Q000502:physiology; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D006224:Cricetinae; D004353:Drug Evaluation, Preclinical; D004357:Drug Synergism; D005069:Evaluation Studies as Topic; D017930:Genes, Reporter; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000138:chemical synthesis / Q000494:pharmacology* / Q000633:toxicity; D008081:Liposomes; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D013501:Surface-Active Agents / Q000138:chemical synthesis / Q000494:pharmacology* / Q000633:toxicity; D014162:Transfection
D000277:Adjuvants, Pharmaceutic; D007093:Imidazoles; D008081:Liposomes; C100541:N-dodecyl-2-imidazole propionate; D016376:Oligonucleotides, Antisense; D013501:Surface-Active Agents; D015500:Chloramphenicol O-Acetyltransferase