title: Exogenous cell-permeable C6 ceramide sensitizes multiple cancer cell lines to Doxorubicin-induced apoptosis by promoting AMPK activation and mTORC1 inhibition.
abstract: New chemotherapy-enhancing strategies are needed for better cancer therapy. Previous studies suggest that exogenous cell-permeable C6 ceramide may be a useful adjunct to the anti-tumor effects of chemotherapeutic agents (such as Taxol) against multiple cancers. Here we demonstrate that exogenous cell-permeable C6 ceramide largely sensitizes multiple progressive cancer cell lines to Doxorubicin-induced cell death and apoptosis. We found for the first time that Doxorubicin induces AMP-activated protein kinase (AMPK) activation in a reactive oxygen species-dependent manner. Activation of AMPK contributes to Doxorubicin-induced cancer cell death and apoptosis. Inhibition of AMPK by small interfering RNA knockdown or a pharmacological inhibitor reduces Doxorubicin-induced cancer cell apoptosis, whereas AMPK activator AICAR enhances it. Importantly, we found that C6 ceramide largely enhances Doxorubicin-induced activation of AMPK, which leads to mTOR complex 1 inhibition and chemo-sensitization. Our data suggest that the combination of C6 ceramide with traditional chemotherapy drugs such as Doxorubicin may have the potential to be used as a new therapeutic intervention against multiple cancers.
authors.affiliation: Department of Dermatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China. surpassing_ji@yahoo.com.cn
authors.forename: C
authors.initials: C
authors.lastname: Ji
authors.forename: B
authors.initials: B
authors.lastname: Yang
authors.forename: Y-L
authors.initials: YL
authors.lastname: Yang
authors.forename: S-H
authors.initials: SH
authors.lastname: He
authors.forename: D-S
authors.initials: DS
authors.lastname: Miao
authors.forename: L
authors.initials: L
authors.lastname: He
authors.forename: Z-G
authors.initials: ZG
authors.lastname: Bi
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D002518:Ceramides / Q000494:pharmacology / Q000627:therapeutic use*; D004317:Doxorubicin / Q000627:therapeutic use*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D006801:Humans; D000076222:Mechanistic Target of Rapamycin Complex 1; D046912:Multiprotein Complexes; D009369:Neoplasms / Q000188:drug therapy*; D011506:Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012265:Ribonucleotides / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases
chemical_list: D000970:Antineoplastic Agents; D002518:Ceramides; D046912:Multiprotein Complexes; D011506:Proteins; D017382:Reactive Oxygen Species; D012265:Ribonucleotides; D000620:Aminoimidazole Carboxamide; D004317:Doxorubicin; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; C031143:AICA ribonucleotide; C504327:N-(alpha-hydroxyoctadecanoyl)phytosphingosine