Regulation of protein translation initiation in response to ionizing radiation

Radiation Oncology

Justine Rudner¹  Stephan M Huber²  Laura Bornes¹  Donatella Trivigno² 

[1] Institute for Cell Biology, University Hospital Essen, Virchowstr. 173, 45147, Essen, Germany;Department of Radiation Oncology, University Hospital of Tuebingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany

关键词: Mcl-1;    Apoptosis;    mTOR;    Akt;    Eukaryotic initiation factor;    Protein translation;    lonizing radiation;   

Others  :  1154584
DOI  :  10.1186/1748-717X-8-35

 received in 2012-08-20, accepted in 2013-02-03,  发布年份 2013

【 摘 要 】

Background

Proliferating tumor cells require continuous protein synthesis. De novo synthesis of most proteins is regulated through cap-dependent translation. Cellular stress such as ionizing radiation (IR) blocks cap-dependent translation resulting in shut-down of global protein translation which saves resources and energy needed for the stress response. At the same time, levels of proteins required for stress response are maintained or even increased. The study aimed to analyze the regulation of signaling pathways controlling protein translation in response to IR and the impact on Mcl-1, an anti-apoptotic and radioprotective protein, which levels rapidly decline upon IR.

Methods

Protein levels and processing were analyzed by Western blot. The assembly of the translational pre-initiation complex was examined by Immunoprecipitation and pull-down experiments with 7-methyl GTP agarose. To analyze IR-induced cell death, dissipation of the mitochondrial membrane potential and DNA fragmentation were determined by flow cytometry. Protein levels of the different initiation factors were down-regulated using RNA interference approach.

Results

IR induced caspase-dependent cleavage of the translational initiation factors eIF4G1, eIF3A, and eIF4B resulting in disassembly of the cap-dependent initiation complex. In addition, DAP5-dependent initiation complex that regulates IRES-dependent translation was disassembled in response to IR. Moreover, IR resulted in dephosphorylation of 4EBP1, an inhibitor of cap-dependent translation upstream of caspase activation. However, knock-down of eIF4G1, eIF4B, DAP5, or 4EBP1 did not affect IR-induced decline of the anti-apoptotic protein Mcl-1.

Conclusion

Our data shows that cap-dependent translation is regulated at several levels in response to IR. However, the experiments indicate that IR-induced Mcl-1 decline is not a consequence of translational inhibition in Jurkat cells.

【 授权许可】

   
2013 Trivigno et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

【 参考文献 】

• [1]Stoneley M, Willis AE: Cellular internal ribosome entry segments: structures, trans-acting factors and regulation of gene expression. Oncogene 2004, 23:3200-3207.
• [2]Hidalgo M, Rowinsky EK: The rapamycin-sensitive signal transduction pathway as a target for cancer therapy. Oncogene 2000, 19:6680-6686.
• [3]Marcotrigiano J, Gingras AC, Sonenberg N, Burley SK: Cap-dependent translation initiation in eukaryotes is regulated by a molecular mimic of eIF4G. Mol Cell 1999, 3:707-716.
• [4]Powley IR, Kondrashov A, Young LA, Dobbyn HC, Hill K, Cannell IG, Stoneley M, Kong YW, Cotes JA, Smith GC, et al.: Translational reprogramming following UVB irradiation is mediated by DNA-PKcs and allows selective recruitment to the polysomes of mRNAs encoding DNA repair enzymes. Genes Dev 2009, 23:1207-1220.
• [5]Spriggs KA, Bushell M, Willis AE: Translational regulation of gene expression during conditions of cell stress. Mol Cell 2010, 40:228-237.
• [6]Marash L, Kimchi A: DAP5 and IRES-mediated translation during programmed cell death. Cell Death Differ 2005, 12:554-562.
• [7]Rudner J, Elsaesser SJ, Muller AC, Belka C, Jendrossek V: Differential effects of anti-apoptotic Bcl-2 family members Mcl-1, Bcl-2, and Bcl-xL on celecoxib-induced apoptosis. Biochem Pharmacol 2010, 79:10-20.
• [8]Wang R, Xia L, Gabrilove J, Waxman S, Jing Y: Downregulation of Mcl-1 through GSK-3beta activation contributes to arsenic trioxide-induced apoptosis in acute myeloid leukemia cells. In Leukemia: official journal of the Leukemia Society of America. UK: Leukemia Research Fund; 2012.
• [9]Adams KW, Cooper GM: Rapid turnover of mcl-1 couples translation to cell survival and apoptosis. J Biol Chem 2007, 282:6192-6200.
• [10]Huber S, Oelsner M, Decker T, Zum Buschenfelde CM, Wagner M, Lutzny G, Kuhnt T, Schmidt B, Oostendorp RA, Peschel C, Ringshausen I: Sorafenib induces cell death in chronic lymphocytic leukemia by translational downregulation of Mcl-1. In Leukemia: official journal of the Leukemia Society of America. UK: Leukemia Research Fund; 2011.
• [11]Trivigno D, Essmann F, Huber SM, Rudner J: Deubiquitinase USP9x confers radioresistance through stabilization of Mcl-1. Neoplasia (New York, NY) 2012, 14:893-904.
• [12]Henis-Korenblit S, Shani G, Sines T, Marash L, Shohat G, Kimchi A: The caspase-cleaved DAP5 protein supports internal ribosome entry site-mediated translation of death proteins. Proc Natl Acad Sci U S A 2002, 99:5400-5405.
• [13]She QB, Halilovic E, Ye Q, Zhen W, Shirasawa S, Sasazuki T, Solit DB, Rosen N: 4E-BP1 is a key effector of the oncogenic activation of the AKT and ERK signaling pathways that integrates their function in tumors. Cancer Cell 2010, 18:39-51.
• [14]Braunstein S, Badura ML, Xi Q, Formenti SC, Schneider RJ: Regulation of protein synthesis by ionizing radiation. Mol Cell Biol 2009, 29:5645-5656.
• [15]Lee T, Pelletier J: Eukaryotic initiation factor 4F: a vulnerability of tumor cells. Future Med Chem 2012, 4:19-31.
• [16]Shahbazian D, Parsyan A, Petroulakis E, Hershey J, Sonenberg N: eIF4B controls survival and proliferation and is regulated by proto-oncogenic signaling pathways. Cell Cycle 2010, 9:4106-4109.
• [17]Zhang L, Pan X, Hershey JW: Individual overexpression of five subunits of human translation initiation factor eIF3 promotes malignant transformation of immortal fibroblast cells. J Biol Chem 2007, 282:5790-5800.
• [18]Liu RY, Dong Z, Liu J, Yin JY, Zhou L, Wu X, Yang Y, Mo W, Huang W, Khoo SK, et al.: Role of eIF3a in regulating cisplatin sensitivity and in translational control of nucleotide excision repair of nasopharyngeal carcinoma. Oncogene 2011.
• [19]Badura M, Braunstein S, Zavadil J, Schneider RJ: DNA damage and eIF4G1 in breast cancer cells reprogram translation for survival and DNA repair mRNAs. Proc Natl Acad Sci U S A 2012, 109:18767-18772.
• [20]Marissen WE, Lloyd RE: Eukaryotic translation initiation factor 4G is targeted for proteolytic cleavage by caspase 3 during inhibition of translation in apoptotic cells. Mol Cell Biol 1998, 18:7565-7574.
• [21]Bushell M, Wood W, Carpenter G, Pain VM, Morley SJ, Clemens MJ: Disruption of the interaction of mammalian protein synthesis eukaryotic initiation factor 4B with the poly(A)-binding protein by caspase- and viral protease-mediated cleavages. J Biol Chem 2001, 276:23922-23928.
• [22]Clemens MJ, Bushell M, Jeffrey IW, Pain VM, Morley SJ: Translation initiation factor modifications and the regulation of protein synthesis in apoptotic cells. Cell Death Differ 2000, 7:603-615.
• [23]Fraser CS, Lee JY, Mayeur GL, Bushell M, Doudna JA, Hershey JW: The j-subunit of human translation initiation factor eIF3 is required for the stable binding of eIF3 and its subcomplexes to 40 S ribosomal subunits in vitro. J Biol Chem 2004, 279:8946-8956.
• [24]Marash L, Liberman N, Henis-Korenblit S, Sivan G, Reem E, Elroy-Stein O, Kimchi A: DAP5 promotes cap-independent translation of Bcl-2 and CDK1 to facilitate cell survival during mitosis. Mol Cell 2008, 30:447-459.
• [25]Rojo F, Najera L, Lirola J, Jimenez J, Guzman M, Sabadell MD, Baselga J, Ramon y Cajal S: 4E-binding protein 1, a cell signaling hallmark in breast cancer that correlates with pathologic grade and prognosis. Clin Cancer Res 2007, 13:81-89.
• [26]Rudner J, Ruiner CE, Handrick R, Eibl HJ, Belka C, Jendrossek V: The Akt-inhibitor Erufosine induces apoptotic cell death in prostate cancer cells and increases the short term effects of ionizing radiation. Radiat Oncol 2010, 5:108. BioMed Central Full Text
• [27]Elia A, Constantinou C, Clemens MJ: Effects of protein phosphorylation on ubiquitination and stability of the translational inhibitor protein 4E-BP1. Oncogene 2008, 27:811-822.
• [28]Schatz JH, Oricchio E, Wolfe AL, Jiang M, Linkov I, Maragulia J, Shi W, Zhang Z, Rajasekhar VK, Pagano NC, et al.: Targeting cap-dependent translation blocks converging survival signals by AKT and PIM kinases in lymphoma. J Exp Med 2011, 208:1799-1807.
• [29]Li Y, Yue P, Deng X, Ueda T, Fukunaga R, Khuri FR, Sun SY: Protein phosphatase 2A negatively regulates eukaryotic initiation factor 4E phosphorylation and eIF4F assembly through direct dephosphorylation of Mnk and eIF4E. Neoplasia (New York, NY) 2010, 12:848-855.
• [30]Skvara H, Thallinger C, Wacheck V, Monia BP, Pehamberger H, Jansen B, Selzer E: Mcl-1 blocks radiation-induced apoptosis and inhibits clonogenic cell death. Anticancer Res 2005, 25:2697-2703.
• [31]Snowden RT, Sun XM, Dyer MJ, Cohen GM: Bisindolylmaleimide IX is a potent inducer of apoptosis in chronic lymphocytic leukaemic cells and activates cleavage of Mcl-1. Leukemia: official journal of the Leukemia Society of America, Leukemia Research Fund, UK 2003, 17:1981-1989.
• [32]Weng C, Li Y, Xu D, Shi Y, Tang H: Specific cleavage of Mcl-1 by caspase-3 in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in Jurkat leukemia T cells. J Biol Chem 2005, 280:10491-10500.
• [33]Ding Q, He X, Hsu JM, Xia W, Chen CT, Li LY, Lee DF, Liu JC, Zhong Q, Wang X, Hung MC: Degradation of Mcl-1 by beta-TrCP mediates glycogen synthase kinase 3-induced tumor suppression and chemosensitization. Mol Cell Biol 2007, 27:4006-4017.
• [34]Inuzuka H, Shaik S, Onoyama I, Gao D, Tseng A, Maser RS, Zhai B, Wan L, Gutierrez A, Lau AW, et al.: SCF(FBW7) regulates cellular apoptosis by targeting MCL1 for ubiquitylation and destruction. Nature 2011, 471:104-109.
• [35]Wertz IE, Kusam S, Lam C, Okamoto T, Sandoval W, Anderson DJ, Helgason E, Ernst JA, Eby M, Liu J, et al.: Sensitivity to antitubulin chemotherapeutics is regulated by MCL1 and FBW7. Nature 2011, 471:110-114.
• [36]Zhong Q, Gao W, Du F, Wang X: Mule/ARF-BP1, a BH3-only E3 ubiquitin ligase, catalyzes the polyubiquitination of Mcl-1 and regulates apoptosis. Cell 2005, 121:1085-1095.
• [37]Schwickart M, Huang X, Lill JR, Liu J, Ferrando R, French DM, Maecker H, O'Rourke K, Bazan F, Eastham-Anderson J, et al.: Deubiquitinase USP9X stabilizes MCL1 and promotes tumour cell survival. Nature 2010, 463:103-107.