Effect of oligomer length and base substitutions on the cytotoxic activity and specific nuclear protein recognition of GTn oligonucleotides in the human leukemic CCRF-CEM cell line.

We have identified phosphodiester oligonucleotides composed of G and T bases, named GTn, which are able to inhibit the cellular growth of human cancer cell lines by recognising specific nuclear proteins. We demonstrated that GTn oligonucleotides require a length of at least 20 nucleotides in order to exert a significant cytotoxic effect and to retain the specific protein binding ability. In addition, we found that GTn cytotoxicity was lost when A or C bases were introduced at either 3' and 5' end or within the GTn sequences.