Various chemical
reagents containing inhibitors of mitochondrial activity,
antioxidants,
nuclear factor-kappa B (
NF-kB) inhibitor,
mammalian target of rapamycin (mTOR) inhibitor and other clinical
therapeutics were screened in order to identify those that selectively decrease the viability of senescent human lung fibroblasts. Cell viability was measured using the
CCK-8 assay. The results showed that
pravastatin, a
drug for
hyperlipidemia, decreased the viability of senescent cells but not non-senescent cells. The effect of
pravastatin on senescent cells is thought to be due to the inhibition of cell proliferation, rather than cell death. The effect of
pravastatin was further investigated using the
glucose metabolism assay, which showed that
glucose consumption was inhibited both in non-senescent and senescent cells and intracellular
nicotinamide adenine dinucleotide (
NAD) was decreased in senescent cells. Changes to the
mRNA expression levels of senescence-associated genes in response to
pravastatin treatment were quantified by real-time-qPCR. There were no significant changes in the relative
mRNA expression levels of IL-1β, p16, p21, and p53 in
pravastatin-treated non-senescent cells, whereas the expression of IL-1β and p16 were increased by
pravastatin only in senescent cells. The results of this study suggest that
pravastatin does not induce senolysis, but rather selectively inhibits the proliferation of senescent cells and that cellular senescence is enhanced by decreasing intracellular
NAD and promoting IL-1β production.