Compounds That Target Novel Cellular Components Involved in HIV-1 Transcription

Abstract

Background: Therapeutic intervention designed to block expression of human immunodeficiency virus (HIV) at a cellular level may slow the clinical progression of HIV-1 disease. Materials and Methods: Cellular models of latent (OM-10.1 and U1) and chronic (8E5) HIV infection were used to evaluate two benzothiophene derivatives, PD 121871 and PD 144795, for an ability to inhibit HIV activation and expression. Results: The benzothiophene derivatives were effective at micromolar concentrations in preventing tumor necrosis factor α (TNFα)-induced HIV-1 expression in OM-10.1 and U1 cultures. These compounds inhibited the activation of HIV-1 transcription; however, this inhibition was selective in that another TNFα-induced response, the transcription of autocrine TNFα, was unaffected. Constitutive HIV-1 expression by chronically infected 8E5 cells was also significantly reduced when treated with these experimental compounds. In TNFα-treated OM-10.1 cultures, the inhibition of HIV-1 transcription by these compounds was not due to a block of nuclear factor-κB induction. The benzothiophene derivatives also inhibited HIV-1 activation by phorbol ester treatment of OM-10.1 promyelocytes, although no inhibition of cellular differentiation toward a macrophage-like phenotype was observed. Furthermore, these experimental compounds induced a state of HIV-1 latency in cytokine-activated OM-10.1 cultures even when maintained under constant TNFα stimulation. The benzothiophene derivatives did not inhibit the activity of the HIV-1 trans-activator. Tat, when evaluated in transient transfection assays. Conclusions: The benzothiophene derivatives appear to inhibit a critical cellular component, distinct from nuclear factor-κB, involved in HIV transcription and may serve to identify new therapeutic targets to restrict HIV expression.