SERPINE1 and neoplasm: While PAI-1 is strongly induced in discodermolide-induced accelerated cell senescence, knockdown of PAI-1 in human tumor cells does not prevent senescence, but rather decelerates senescence induction, suggesting that in this context, PAI-1 acts as a modulator of senescence onset, an observation that is consistent with the redundant nature of senescence (Laura Klein, unpublished data).