With the aim to develop novel antiproliferative agents, a new series of eighteen dihydroxylated 2,6-diphenyl-4-chlorophenylpyridines were systematically designed, prepared, and investigated for their topoisomerase (
topo) I and IIα inhibitory properties and antiproliferative effect in three different human
cancer cell lines (HCT15, T47D, and HeLa). Compounds 22-30 which possess a meta- or para-
phenol on 2-, or 6-position of central
pyridine ring showed significant dual
topo I and
topo IIα inhibitory activities with strong antiproliferative activities against all the tested human
cancer cell lines. However, compounds 13-21 which possess an ortho-
phenol on 2-, or 6-position of central
pyridine ring did not show significant
topo I and
topo IIα inhibitory activities but displayed moderate antiproliferative activities against all the tested human
cancer cell lines. Compound 23 exhibited the highest antiproliferative potency as much as 348.5 and 105 times compared to
etoposide and
camptothecin, respectively, in T47D
cancer cell line. The structure-activity relationship study revealed that the para position of a
hydroxyl group at 2-and 6-phenyl ring and
chlorine atom at the para position of 4-phenyl ring of the central
pyridine exhibited the most significant
topo I and
topo IIα inhibition, which might indicate introduction of the
chlorine atom at the phenyl ring of 4-pyridine have an important role as dual inhibitors of
topo I and
topo IIα.
Compound 30 which showed the most potent dual
topo I and
topo IIα inhibition with strong antiproliferative activity in T47D cell line was selected to perform further study on the mechanism of action, which revealed that
compound 30 functions as a potent
DNA non-intercalative catalytic
topo I and IIα dual inhibitor.