Novel short oligonucleotide conjugates as inhibitors of human telomerase.

A series of oligonucleotide conjugates were designed and synthesized as novel inhibitors of human telomerase. These compounds contain a relatively short (6-7-mer) oligonucleotide domain, with an N3'-->P5' phosphoramidate (np) or thio-phosphoramidate (nps) backbone, targeted to the template region of the RNA component of the enzyme and various pendant groups attached to either their 5'- or preferably to the 3'-termini. The most potent compounds in the series inhibited telomerase with low nM IC50 values in biochemical assays whereas the cognate oligonucleotides without the pendant groups were significantly less active having IC50 values 100-1000-fold higher.