2.3. Mode of action
The mode of action of PPT is to polymerize tubulin, thus destabilize
mitotic-spindles microtubules and prevent cell division. Various
semi-synthetic products of PPT, such as etoposide and, teniposide act
directly on the enzyme topoisomerase II and form an irreversible
enzyme-DNA complex resulting n DNA double-strand breaks
(Hartmann and Lipp, 2006). Both
inhibitory effects of PPT on microtubulin formation and topoisomerase II
are depicted in Fig. 3 .