title: Specific HIV protease inhibitors inhibit the ability of HPV16 E6 to degrade p53 and selectively kill E6-dependent cervical carcinoma cells in vitro.
abstract: Although HIV protease inhibitor (PI) drugs predominantly target HIV proteases 1 and 2, it is also known that part of their efficacy is due to selective inhibition of the proteasome. The pathogenicity of high-risk human papilloma virus (HPV) is dependent on expression of viral E6 proteins which inappropriately activate the 26S proteasome to degrade p53 and other cellular proteins that are detrimental to viral replication. Comparison of the ability of the PIs indinavir, ritonavir, amprenavir, lopinavir, atazanavir, nelfinavir and saquinavir to inhibit E6-mediated proteasomal degradation of mutant p53 in E6-transfected C33A cells showed that 15 microM lopinavir, 1 mM indinavir or 125 microM ritonavir treatment for 24 h produced a stable increase in the level of nuclear p53 in these cells with minimal cell death. After 4 h exposure of HPV16+ve SiHa cells to 15 microM lopinavir, a transient increase in wild-type p53 expression was observed associated with a 7% reduction in the chymotryptic activity of the 205 proteasome and apoptosis after 24h. Comparison of growth rates of PI treated SiHa, CaSki, C33A, C33A-E6 and non-transformed NIH/3T3 cells showed that SiHa were the most sensitive, whereas NIH/3T3 were least affected. In conclusion, these data show that specific HIV PIs such as lopinavir and possibly indinavir, can induce selective toxicity of HPV-transformed cervical carcinoma cells expressing wild-type p53 and may form the basis of a topically applied alternative to surgery for the treatment of HPV-related premalignant lesions of the cervix.
authors.affiliation: University of Manchester Gynaecological Oncology Laboratories, Human Development, St Mary's Hospital, Manchester M13 OJH. lynne.hampson@manchester.ac.uk
authors.forename: Lynne
authors.initials: L
authors.lastname: Hampson
authors.forename: Henry C
authors.initials: HC
authors.lastname: Kitchener
authors.forename: Ian N
authors.initials: IN
authors.lastname: Hampson
mesh_terms: D000818:Animals; D002277:Carcinoma / Q000188:drug therapy / Q000821:virology; D045744:Cell Line, Tumor / Q000187:drug effects; D005260:Female; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D006801:Humans; D061466:Lopinavir; D051379:Mice; D041681:NIH 3T3 Cells; D009856:Oncogene Proteins, Viral / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011744:Pyrimidinones / Q000494:pharmacology*; D012097:Repressor Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy / Q000821:virology
chemical_list: C068651:E6 protein, Human papillomavirus type 16; D017320:HIV Protease Inhibitors; D009856:Oncogene Proteins, Viral; D011744:Pyrimidinones; D012097:Repressor Proteins; D016159:Tumor Suppressor Protein p53; D061466:Lopinavir; D046988:Proteasome Endopeptidase Complex