title: Therapeutic metformin/AMPK activation blocked lymphoma cell growth via inhibition of mTOR pathway and induction of autophagy.
abstract: Adenosine monophosphate-activated protein kinase (AMPK) acts as a major sensor of cellular energy status in cancers and is critically involved in cell sensitivity to anticancer agents. Here, we showed that AMPK was inactivated in lymphoma and related to the upregulation of the mammalian target of rapamycin (mTOR) pathway. AMPK activator metformin potentially inhibited the growth of B- and T-lymphoma cells. Strong antitumor effect was also observed on primary lymphoma cells while sparing normal hematopoiesis ex vivo. Metformin-induced AMPK activation was associated with the inhibition of the mTOR signaling without involving AKT. Moreover, lymphoma cell response to the chemotherapeutic agent doxorubicin and mTOR inhibitor temsirolimus was significantly enhanced when co-treated with metformin. Pharmacologic and molecular knock-down of AMPK attenuated metformin-mediated lymphoma cell growth inhibition and drug sensitization. In vivo, metformin induced AMPK activation, mTOR inhibition and remarkably blocked tumor growth in murine lymphoma xenografts. Of note, metformin was equally effective when given orally. Combined treatment of oral metformin with doxorubicin or temsirolimus triggered lymphoma cell autophagy and functioned more efficiently than either agent alone. Taken together, these data provided first evidence for the growth-inhibitory and drug-sensitizing effect of metformin on lymphoma. Selectively targeting mTOR pathway through AMPK activation may thus represent a promising new strategy to improve treatment of lymphoma patients.
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: W-Y
authors.initials: WY
authors.lastname: Shi
authors.forename: D
authors.initials: D
authors.lastname: Xiao
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.forename: L-H
authors.initials: LH
authors.lastname: Dong
authors.forename: Z-X
authors.initials: ZX
authors.lastname: Yan
authors.forename: Z-X
authors.initials: ZX
authors.lastname: Shen
authors.forename: S-J
authors.initials: SJ
authors.lastname: Chen
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: W-L
authors.initials: WL
authors.lastname: Zhao
mesh_terms: D000091162:AMP-Activated Protein Kinase Kinases; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001343:Autophagy / Q000187:drug effects*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology; D004357:Drug Synergism; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D016393:Lymphoma, B-Cell / Q000188:drug therapy / Q000473:pathology*; D016399:Lymphoma, T-Cell / Q000473:pathology*; D008687:Metformin / Q000494:pharmacology* / Q000627:therapeutic use; D051379:Mice; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D020123:Sirolimus / Q000031:analogs & derivatives / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D047428:Protein Kinase Inhibitors; C401859:temsirolimus; D004317:Doxorubicin; D008687:Metformin; D011494:Protein Kinases; C546843:mTOR protein, mouse; D058570:TOR Serine-Threonine Kinases; D000091162:AMP-Activated Protein Kinase Kinases; D020123:Sirolimus