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

Abstract

Therapeutic intervention designed to block expression of human immunodeficiency virus (HIV) at a cellular level may slow the clinical progression of HIV-1 disease. 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. The benzothiophene derivatives were effective at micromolar concentrations in preventing tumor necrosis factor alpha (TNF alpha)-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 TNF alpha-induced response, the transcription of autocrine TNF alpha, was unaffected. Constitutive HIV-1 expression by chronically infected 8E5 cells was also significantly reduced when treated with these experimental compounds. In TNF alpha-treated OM-10.1 cultures, the inhibition of HIV-1 transcription by these compounds was not due to a block of nuclear factor-kappa B 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 TNF alpha stimulation. The benzothiophene derivatives did not inhibit the activity of the HIV-1 trans-activator, Tat, when evaluated in transient transfection assays. The benzothiophene derivatives appear to inhibit a critical cellular component, distinct from nuclear factor-kappa B, involved in HIV transcription and may serve to identify new therapeutic targets to restrict HIV expression.