Original ArticleVincristine Attenuates N-methyl-N′-nitro-N-nitrosoguanidine-Induced Poly-(ADP) Ribose Polymerase Activity in CardiomyocytesZhang, Jianqing PhD*; Chatterjee, Kanu MB, FRCP†‡‖; Alano, Conrad C PhD¶; Kalinowski, Mikaila A**; Honbo, Norman MA*; Karliner, Joel S MD*†‡§Author Information From the *Cardiology Section, VA Medical Center, San Francisco, CA; †Cardiology Division, ‡Department of Medicine, §Cardiovascular Research Institute, ‖Chatterjee Center for Cardiac Research, University of California, San Francisco, CA; ¶Department of Neurology, University of California, San Francisco and VA Medical Center; and **Lewis & Clark College, Portland, OR. Received for publication September 23, 2009; accepted October 20, 2009. Supported by the Foundation for Cardiac Research, University of California San Francisco (K.C.); POI HL68738 and 1R01 HL090606 (J.S.K.) from the National Heart, Lung, and Blood Institute, National Institutes of Health; and a VA Merit Award from the Research Service, Department of Veterans Affairs (C.C.A.). J.Z. and K.C. contributed equally to this work. The authors report no conflicts of interest. Reprints: Joel S. Karliner, MD, Cardiology Section (111C5), VA Medical Center, 4150 Clement Street, San Francisco, CA 94121 (e-mail: [email protected]). Journal of Cardiovascular Pharmacology: March 2010 - Volume 55 - Issue 3 - p 219-226 doi: 10.1097/FJC.0b013e3181c87e6c Buy Metrics Abstract The DNA-damaging agent N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) causes cardiomyocyte death as a result of energy loss from excessive activation of poly-(ADP) ribose polymerase-1 (PARP-1) resulting in depletion of its substrates nicotinamide adenine dinucleotide (NAD+) and ATP. Previously we showed that the chemotherapeutic agent vincristine (VCR) is cardioprotective. Here we tested the hypothesis that VCR inhibits MNNG-induced PARP activation. Adult mouse cardiomyocytes were incubated with 100 μmol/L MNNG with or without concurrent VCR (20 μmol/L) for 2 to 4 hours. Cardiomyocyte survival was measured using the trypan blue exclusion assay. Western blots were used to measure signaling responses. MNNG-induced cardiomyocyte damage was time- and concentration-dependent. MNNG activated PARP-1 and depleted NAD+ and ATP. VCR completely protected cardiomyocytes from MNNG-induced cell damage and maintained intracellular levels of NAD+ and ATP. VCR increased phosphorylation of the prosurvival signals Akt, GSK-3β, Erk1/2, and p70S6 kinase. VCR delayed PARP activation as evidenced by Western blot and by immunofluorescence staining of poly (ADP)-ribose, but without directly inhibiting PARP-1 itself. Known PARP-1 inhibitors also protected cardiomyocytes from MNNG-induced death. Repletion of ATP, NAD, pyruvate, and glutamine had effects similar to PARP-1 inhibitors. We conclude that VCR protects cardiomyocytes from MNNG toxicity by regulating PARP-1 activation, intracellular energy metabolism, and prosurvival signaling. © 2010 Lippincott Williams & Wilkins, Inc.