Anti-gene peptide nucleic acid targeted to proviral HIV-1 DNA inhibits in vitro HIV-1 replication

Highly active antiretroviral therapy (HAART) is unlikely to affect reservoirs of HIV in latently infected cells. Anti-gene compounds, such as peptide nucleic acids (PNAs), which block transcriptional activity via sequence-specific invasion of double-stranded DNA may be an effective strategy to target cells harbouring proviral HIV DNA. Here we show that a PNA oligomer (PNA(HIV)), 15 bases in length, linked to a nuclear localization signal (NLS), substantially suppressed HIV-1 replication in chronically infected lymphocytes and macrophages and efficiently prevented mitogen-induced HIV-1 reactivation in lymphocytes, as determined by HIV-p24 antigen production in supernatants and FACS analysis for intracellular HIV accumulation. In contrast, a mismatched PNA did not show any effect on HIV expression. Semi-quantitative RT-PCR and quantitative real-time RT-PCR demonstrated a decrease of HIV RNA expression in infected cells treated by PNA(HIV) indicating that inhibition of HIV-1 replication occurred at the transcription step. In conclusion, the use of anti-gene PNA to target the HIV-1 proviral DNA in the quest for new antiretroviral agents appears quite promising.