Verrucarin A reduces the transcriptional activities of SRCs in HeLa cells.

(A) Chemical structure of verrucarin A. (B) Verrucarin A inhibits pBIND-SRC luciferase activity. HeLa cells were transiently cotransfected with expression vectors for pBIND-SRC-1, pBIND-SRC-2 or pBIND-SRC-3 and the GAL4-responsive pGL5 reporter plasmid before incubation with verrucarin A at different concentrations (0, 1, 2, 5, and 10 nM) for 24 h, followed by luciferase assay. Empty pBIND vector was transfected as a negative control. (C) Verrucarin A inhibits SRC coactivation of ERα. Luciferase assays were performed in HeLa cells transiently transfected with an ERE-luc reporter vector and expression vectors for ERα, and pCR3.1-SRC before incubation with 10 nM E2 and verrucarin A at different concentrations (0, 2, 5, and 10 nM) for 24 h.