Abstract
Abstract. Ferroptosis is a novel non-apoptotic form of cell
death characterized by iron-dependent reactive oxygen species
(ROS)-mediated lipid peroxidation. In several different cell systems,
the tumor suppressor p53 can enhance sensitivity to ferroptotic
inducers. At least half of all human cancers show loss of function of
p53. Furthermore, many of those tumors express mutant forms of p53 that
has lost its wild-type function. Several groups have designed small
molecules that can reactivate the wild-type function of these missense
p53 mutants. We reasoned that p53 reactivators may also enhances
sensitivity of certain cancer cells to ferroptosis stimuli. To test this
idea we combined a number of different p53 reactivators with small
molecule inducers of ferroptosis. In contrast, we observed that several
p53 reactivators protected cells from cell death induced by ferroptotic
inducers. Suprisingly, this protection still occurred in p53-null cell
lines. We observed that these reactivators were neither free radical
scavengers nor ion chelators. One of these p53 reactivator molecules,
NSC 59984, reduced expression of GPX4, which is unlikely to explain the
ability to reduced sensitivity to ferroptosis. We suggested that these
p53 reactivators function via an unknown, p53-independent manner to
suppress ferroptosis.