NF-kappa B-independent suppression of HIV expression
by ascorbic acid.
AIDS Res Hum Retroviruses 1997 Feb 10;13(3):235-9 (ISSN: 0889-2229)
Harakeh S; Jariwalla RJ
Linus Pauling Institute of Science and Medicine, Palo Alto, California
Ascorbic acid (ascorbate or vitamin C) has been shown to suppress the induction
of HIV in latently infected T lymphocytic cells following stimulation with
a tumor promoter (PMA) and inflammatory cytokine (TNF-alpha). To assess
whether this inhibition was mediated via modulation of the cellular transcription
factor, NF-kappa B, we carried out gel shift analysis on nuclear extracts
prepared under different conditions of cell stimulation in the presence
or absence of ascorbate, N-acetylcysteine (NAC), or zidovudine (AZT). Pretreatment
of ACH-2 T cells by NAC followed by stimulation with PMA, TNF-alpha, or
hydrogen peroxide (H2O2) resulted in strong suppression of NF-kappa B activation.
In contrast, neither ascorbate nor AZT affected NF-kappa B activity under
all three induction conditions in the ACH-2 cell line. Ascorbate and AZT
also had no effect on NF-kappa B activation following TNF-alpha- or PMA-induced
stimulation of U1 promonocytic cells. These results suggest that the molecular
mechanism of HIV inhibition by ascorbate is not mediated via NF-kappa B
inhibition, unlike that seen with other antioxidants.