In the present study the in vitro antiviral activity of dehydroepiandrosterone (DHEA) and 17 synthetic
derivatives against herpes simplex type 1 (HSV-1) was determined. DHEA, epiandrosterone (EA), two
synthetic DHEA analogs and three synthetic EA analogs showed a selective inhibitory effect on HSV
in vitro multiplication. DHEA and E2, a synthetic derivative of EA, were not found to be virucidal to
cell-free HSV-1 and did not impair virus adsorption or penetration. We determined that treatment with
both compounds decreased viral protein synthesis. Moreover, inhibitory effect of DHEA and E2 on extracellular
viral titer was stronger than the inhibition found on total viral infectivity, suggesting that the
antiherpetic activity of these compounds may also be in part due to an inhibition in virus formation
and release.
Since DHEA is a known Raf/MEK/ERK signaling pathway activator, we studied the role of this pathway
on HSV-1 infection. ERK1/2 phosphorylation was stimulated in HSV-1 infected cultures. UO126, a Raf/
MEK/ERK signaling pathway inhibitor, impaired viral multiplication, while anisomycin, an activator of
this pathway, enhanced it.
Treatment with DHEA 6 h before infection enhanced HSV-1 multiplication. On the contrary, pre-treatment
with E2, which does not modulate Raf/MEK/ERK signaling pathway, did not produce an increase of
viral replication. Taking together these results, the antiviral activity of DHEA seems to occur via a mechanism
independent of its ability to modulate ERK phosphorylation.