The eef2 Kinase Confers Resistance to Nutrient Deprivation by Blocking Translation Elongation

Transcription

1 The eef2 Kinase Confers Resistance to Nutrient Deprivation by Blocking Translation Elongation Gabriel Leprivier, 1 Marc Remke, 2,3,4 Barak Rotblat, 1 Adrian Dubuc, 2,3 Abigail-Rachele F. Mateo, 3,6 Marcel Kool, 4 Sameer Agnihotri, 2 Amal El-Naggar, 1 Bin Yu, 6 Syam Prakash Somasekharan, 1 Brandon Faubert, 7 Gaëlle Bridon, 8 Cristina E. Tognon, 1 Joan Mathers, 1 Ryan Thomas, 1 Amy Li, 1 Adi Barokas, 1 Brian Kwok, 1 Mary Bowden, 9 Stephanie Smith, 9 Xiaochong Wu, 2,3 Andrey Korshunov, 10 Thomas Hielscher, 5 Paul A. Northcott, 2 Jason D. Galpin, 11 Christopher A. Ahern, 11 Ye Wang, 12 Martin G. McCabe, 13,14 V. Peter Collins, 14 Russell G. Jones, 7 Michael Pollak, 12 Olivier Delattre, 15 Martin E. Gleave, 9 Eric Jan, 16 Stefan M. Pfister, 4,17 Christopher G. Proud, 18 W. Brent Derry, 3,6 Michael D. Taylor, 2,3 and Poul H. Sorensen 1, * Cell 153, , May 23, Elsevier Inc. Nick Arndt,

2 IntroducAon - Nutrient DeprivaAon (ND) è strong physiological stress è worst consequences for cell viability Nutrient DeprivaAon - organisms evolved molecular mechanisms to respond to ND - a key mediator is the highly conserved energy sensor AMP- acavated protein kinase (AMPK) - acavated when cellular AMP:ATP or ADP:ATP raaos increase - AMPK iniduces catabolic processes such as glycolysis and fagy acid oxidaion to preserve energy - AMPK limits energy- consuming processes such as proliferaion and protein synthesis 2

3 IntroducAon - AMPK directly acavates eef2k under ND - mtorc1 and and Ras- Erk- p90rsk pathways inhibit eef2k under normal condiaons è acavity of eef2k controlled by nutrient availability B D paper demonstrate a criacal role for eef2k in protecang normal Assues from acute ND - this through inhibiaon of eef2 and how this pathway is exploited by tumor cells in adapang to metabolic stress 3

4 1.) eef2k Is CriAcal for Cell Survival under ND Mouse Embryonic Fibroblasts (MEF) - cells lacking eef2k (eef2k - / - MEFs) were highly sensiave to ND compared with WT (eef2k + / + MEFs) and underwent apoptoac cell death - eef2 knockdown (eef2k - / - ) markedly increased cell survival compared to sirna controls 4

5 1.) eef2k Is CriAcal for Cell Survival under ND - eef2k knockdown in NIH 3T3 cells with two independent eef2k sirnas strongly sensiized cells to ND - knockdown of eef2 completely rescued cells from cell death 5

6 1.) eef2k Is CriAcal for Cell Survival under ND è eef2k mediates survival under ND through its control of eef2 è eef2k is required for cell survival under acute ND 6

7 2.) AdaptaAon of Transformed Cells to Chronic ND Correlates with Increased AMPK- eef2k Pathway AcAvaAon - NIH 3T3 fibroblasts transformed by acavated K- RasV12 (RasV12) or the ETV6- NTRK3 (EN) chimeric tyrosine kinase - oncoproteins consatuavely acavate Ras- Erk and PI3K- Akt B D 7

8 2.) AdaptaAon of Transformed Cells to Chronic ND Correlates with Increased AMPK- eef2k Pathway AcAvaAon Immunoblot analysis NIH 3T3 - mtorc1 was inhibited in all three cell lines by ND - AMPK acavity lesser in transformed cells under ND, as indicated by reduced phosphorylaion of AMPK or acetyl CoA- carboxylase (ACC) - phosphorylaaon of eef2 was markedly blunted under ND in transformed cells - EEF2 is more acav in transformed cells - Thr56 is phosphorylated by eef2 kinase (eef2k), the only known kinase for eef2, to block acivity 8

9 2.) AdaptaAon of Transformed Cells to Chronic ND Correlates with Increased AMPK- eef2k Pathway AcAvaAon - transformed cells were subjected to repeated cycles of prolonged ND followed by nutrient resupplementaaon - a[er several weeks emerged stable populaaons with the capacity to survive under acute ND Intracellular levels of AMP and ATP 9

10 2.) AdaptaAon of Transformed Cells to Chronic ND Correlates with Increased AMPK- eef2k Pathway AcAvaAon Immunoblot analysis NIH 3T3 - mtorc1 was inhibited in all cell lines by ND - selected cells increased AMPK and ACC phosphorylaaon under ND, suggesing cells had reacquired ability to acavate AMPK under ND - correlated with increased eef2 phosphorylaaon and confirms a correlaion between eef2 phosphorylaion and survival capacity under ND - was not due to inhibiaon of the Ras- Erk p90rsk pathway, as eef2k Ser366 phosphorylaion was preserved in selected cells under ND 10

11 2.) AdaptaAon of Transformed Cells to Chronic ND Correlates with Increased AMPK- eef2k Pathway AcAvaAon - results confirmed in HeLa, MG63 cells and animal experiments 11

12 3.) E"1 (eef2k ortholog) promotes survival of C. elegans under nutrient deprivaaon è protecave role of eef2k seems to be highly conserved starvaaon - deleaon of e_- 1 had only a minor effect on lifespans of animals grown under nutrientrich condiaons but survival was substanaally reduced under ND 12

13 4.) eef2k expression predicts poor prognosis in aggressive brain tumors - to probe these findings in primary human tumor they focus on: - eef2k expression was significantly upregulated in glioblastoma mulaforme (GBM) compared to medulloblastoma (MB), the most common malignant brain tumor of childhood normal human brain Issue (2.5- fold) glioblastoma mulaforme (GBM), the most highly malignant adult brain tumor - eef2k expression data publically aviable for these tumors - among GBM subtypes, eef2k expression was specifically increased in classical and mesenchymal subtypes, both of which are associated with poor overall survival - eef2k expression strongly correlated with decreased overall survival across all human glioma subtypes 13

14 Summary eef2k is required for cell survival under acute nutrient deprivaion AMPK- eef2k reacivaion supports adaptaion of transformed cells to nutrient stress E"1 (eef2k ortholog) promotes survival of C. elegans under nutrient deprivaion eef2k expression predicts poor prognosis in aggressive brain tumors 14

15 Summary 15