MP55-11 SYNTHETIC LETHAL METABOLIC TARGETING OF CELLULAR SENESCENCE IN PROSTATE CANCER WITH METFORMIN

Abstract

You have accessJournal of UrologyProstate Cancer: Basic Research III1 Apr 2015MP55-11 SYNTHETIC LETHAL METABOLIC TARGETING OF CELLULAR SENESCENCE IN PROSTATE CANCER WITH METFORMIN Michael L. Blute, Bing Yang, Nathan Damaschke, Dudley Lamming, F. Michael Hoffman, and David F. Jarrard Michael L. BluteMichael L. Blute More articles by this author , Bing YangBing Yang More articles by this author , Nathan DamaschkeNathan Damaschke More articles by this author , Dudley LammingDudley Lamming More articles by this author , F. Michael HoffmanF. Michael Hoffman More articles by this author , and David F. JarrardDavid F. Jarrard More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.2054AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Cellular senescence occurs in response to sub-lethal stress after androgen deprivation therapy, radiation and chemotherapy whereby cells exit the cell cycle and develop distinct morphologic and biochemical characteristics. Senescence is a therapeutic approach, however potentially deleterious consequences make elimination of these cells important. The objective of this study was to determine whether the increased gluconeogenesis induced during senescence could be exploited to synergistically eliminate PCa cells using metformin (Met), an oral biguanide hyperglycemic approved for type II diabetes. METHODS High throughput screening of small molecule collections identified two novel robust senescence inducing agents, AZQ (diaziquone) a quinone and AZD5438 a novel CDK inhibitor. Senescence was confirmed using beta-galactosidase staining, cell arrest and increased size by flow cytometry. mTOR a serine-threonine protein kinase activity was evaluated using western. PCa cells were seeded on 96-well plates, low(L) and high(H) AZQ (0.1 and 0.25 microM) or AZD 5438 (0.1 and 0.4 microM) concentrations administered and after 3 days of senescence induction Met (1 and 5mM) added. Cells were collected 24 and 72h later and stained with Hoechts to evaluate the cell number. CalcuSyn software (Biosoft, Cambridge, UK) modeled synergism. RESULTS AZQ and AZD robustly increased beta-galactosidase staining, cell size and p27 and p16 induction in Du145, PC3, PPC1 cell lines. mTOR signaling through mTOR complex 1 significantly increased in AZQ-induced senescent cells. Used alone, AZD(L) and AZQ(L) demonstrate a 30% reduction in cell number and Met(L) alone 18%. Met after senescence induction (72h) decreased cell number 70% and 55% (AZD and AZQ respectively). CalcuSyn calculations revealed moderate synergistic effects with combinations of either AZD(H) or AZQ (L and H) and Met(L and H) at 24hr. A strong synergistic decrease in cell viability was demonstrated at 72h with AZQ(H) and Met(L) (CI= 0.267). CONCLUSIONS Senescent cells targeted by metformin may offer an alternative treatment strategy for removing castrate-resistant PCa cells. Increased gluconeogenesis during senescence represents a novel ‘Achilles heel’ for these dormant/arrested cancer cells. mTOR activity is activated during the conversion of cells to senescence, and Met inhibition of this pathway is a putative mechanism. Our results suggest that combination treatment with a senescence-inducing drug and metformin may be a feasible targeted therapeutic approach. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e677 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Michael L. Blute More articles by this author Bing Yang More articles by this author Nathan Damaschke More articles by this author Dudley Lamming More articles by this author F. Michael Hoffman More articles by this author David F. Jarrard More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...