This study was performed to explore the feasibility of antisense imaging with radiolabeled
antisense oligonucleotides DNA in tumored nude mice in vivo. Two different tumor cell lines, KB-G2 and KB-31,were used; both antisense and control sense DNAs were administrated intratumorally. The hybridization activities analysis of MAG3 conjugated DNAs
oligonucleotides was demonstrated by
Polyacrylamide Gel Electrophoresis. The whole body imaging was performed 22 h after administration of radiolabeled antisense and control sense DNAs at 1.0 microg DNAs (100 microCi) in 100 microl per animal. Then the animals were sacrificed at 24 h after administration and the organs and tissues were dissected and weighed; the radioactivity of each sample was detected by r-counter; injection dose percentage per gram tissue (%ID/g) was calculated and the biodistribution obtained. Both MAGS conjugated
oligonucleotides DNAs and natural
oligonucleotides DNAs have the same hybridization activities. The whole body images demonstrate improved targeting of antisense DNAs vs sense DNAs in the KB-G2 but not the KB-31 animals.
Tumor levels in the KB-G2 animals were significantly higher for the antisense DNAs vs sense DNAs (14.7 vs 8.5% ID/g) while this difference (8.6 vs 4.3% ID/g) was insignificant in the KB-31 animals. Evidence for
tumor targeting in vivo by an antisense in that mechanism has been obtained; statistically higher
tumor accumulations of the 99mTc-antisense
DNA were observed when compared to the control 99mTc-sense
DNA. The successful localization of
antisense DNA in
tumor demonstrates that antisense
tumor targeting in vivo is feasible even though improvement in
tumor delivery and normal tissue clearance are needed for practical antisense imaging.