Abstract
Although DNA damaging agents have revolutionized chemotherapy against solid tumors, a narrow therapeutic window combined with severe side effects has limited their broader use. Here we show that RAD001 (everolimus), a rapamycin derivative, dramatically enhances cisplatin-induced apoptosis in wild-type p53, but not mutant p53 tumor cells. The use of isogenic tumor cell lines expressing either wild-type mTOR cDNA or a mutant that does not bind RAD001 demonstrates that the effects of RAD001 are through inhibition of mTOR function. We further show that RAD001 sensitizes cells to cisplatin by inhibiting p53-induced p21 expression. Unexpectedly, this effect is attributed to a small but significant inhibition of p21 translation combined with its short half-life. These findings provide the molecular rationale for combining DNA damaging agents with RAD001, showing that a general effect on a major anabolic process may dramatically enhance the efficacy of an established drug protocol in the treatment of cancer patients with solid tumors.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antineoplastic Agents / pharmacology*
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Apoptosis / drug effects*
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Apoptosis / genetics
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Apoptosis / physiology*
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Cell Cycle Proteins / antagonists & inhibitors*
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Cell Cycle Proteins / genetics
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Cell Survival / drug effects
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Cell Survival / genetics
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Cell Survival / physiology
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Cisplatin / pharmacology*
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Cyclin-Dependent Kinase Inhibitor p21
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DNA Damage / drug effects
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DNA Damage / genetics
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DNA Damage / physiology
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Drug Synergism
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Everolimus
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Humans
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Mutation
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Polyribosomes / drug effects
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Polyribosomes / genetics
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Polyribosomes / metabolism
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Protein Biosynthesis / drug effects*
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Protein Biosynthesis / genetics
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Protein Biosynthesis / physiology
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Protein Kinases / genetics
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Protein Kinases / metabolism*
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RNA, Small Interfering / genetics
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RNA, Small Interfering / metabolism
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Sirolimus / analogs & derivatives*
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Sirolimus / pharmacology*
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TOR Serine-Threonine Kinases
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Tumor Cells, Cultured
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Tumor Suppressor Protein p53 / genetics
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Tumor Suppressor Protein p53 / metabolism
Substances
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Antineoplastic Agents
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CDKN1A protein, human
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Cell Cycle Proteins
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Cyclin-Dependent Kinase Inhibitor p21
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RNA, Small Interfering
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Tumor Suppressor Protein p53
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Everolimus
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Protein Kinases
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MTOR protein, human
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TOR Serine-Threonine Kinases
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Cisplatin
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Sirolimus