BIOLOGIC ACTIVITY OF OLIGONUCLEOTIDES WITH POLARITY AND ANOMERIC CENTER REVERSAL

Human papillomavirus (HPV) type 16 E6 and E7 inactivate the tumor supp ressors p53 and pRB, respectively. Both viral oncoproteins play import ant roles in maintaining the transformed phenotype of cells. In this s tudy, we examine the effects of antisense oligodeoxynucleotides with p olarity and anomeric center reversal (alpha/beta-PODNs). ODNs of the g eneral structure 5'alpha N3'3'NNN5'5'alpha N3'3'NNNN5'5'alpha N3'3'NNN N5'5'alpha N3'3'N5' were synthesized using phosphoramidite DNA chemist ry. These alpha/beta-ODNs were complementary in sequence to regions fl anking the start codons of HPV type 16 E6 and E7 genes. The anti-HPV t ype 16 alpha/beta-ODNs were able to form stable duplexes with their co mplementary RNA, which then serve as substrates for RNase H hydrolysis , Anti-HPV type 16 alpha/beta-ODNs also specifically inhibited the gro wth of two cervical carcinoma cell lines, CaSki and SiHa, both of whic h harbor HPV type 16 DNA. A decrease in E7 protein expression was also observed. Injection of nude mice with SiHa cells induces tumors. Trea tment of these tumor-bearing mice with anti-HPV type 16 alpha/beta-ODN s led to substantially smaller tumors. These results show that alpha/b eta-ODNs can exert antisense activities both in vitro and in vivo on t he E6 and E7 genes of HPV type 16.