Anti-sense phosphorothioate oligonucleotides have both specific and non-specific effects on cells containing human papillomavirus type 16.

A range of specific nuclease resistant phosphorothioate oligodeoxynucleotides (S-oligos) complementary to mRNA of human papillomavirus type 16 (HPV16), were tested for their ability to inhibit cell proliferation and to alter the level of HPV-specific mRNA and proteins in CaSki cells, a human cervical carcinoma cell line containing HPV16 DNA. Only certain of the S-oligos to the viral upstream regulatory region (URR) and the early viral open reading frames (ORF), E6 and E7, were found to display any activity on the cells. These S-oligos were found to exhibit potent anti-proliferative activity at concentrations between 0.25 microM and 20 microM, inhibiting the uptake of [3H]-thymidine into CaSki cells by up to 90% at higher concentrations. The rate of synthesis of E6 and E7 proteins and the steady state level of the E7 protein however remained largely unchanged. E7 protein exhibited a greater decrease in phosphorylation in the presence of only one of the antisense oligos. Other S-oligos including a random sequence, unmodified sequences or O-methylphosphonate modified oligos, had no specific effect on the cells. The results imply that the anti-sense S-oligonucleotides had both specific anti-HPV16 and other non-specific effects on cell proliferation and synthesis of virally encoded proteins.