Binding of f-PIP, a pyrrole- and imidazole-containing triamide, to the inverted CCAAT box-2 of the topoisomerase IIα promoter and modulation of gene expression in cells

An N-formamido pyrrole- and imidazole-containing triamide (f-PIP) has been shown by DNase I footprinting, SPR, and CD studies to bind as a stacked dimer to its cognate sequences: 5′-TACGAT-3′ (5′-flank of the inverted CCAAT box-2 of the human topoisomerase IIα promoter) and 5′-ATCGAT-3′. A gel shift experiment provided evidence for f-PIP to inhibit protein–DNA interaction at the ICB2 site. Western blot studies showed that expression of the topoisomerase IIα gene in confluent NIH 3T3 cells was induced by treatment with f-PIP. The results suggested that the triamide was able to enter the nucleus, interacted with the target site within ICB2, inhibited NF-Y binding, and activated gene expression.