Combined inhibition of PI3K-related DNA damage response kinases and mTORC1 induces apoptosis in MYC-driven B-cell lymphomas.

Pharmacological strategies capable of directly targeting MYC are elusive. Previous studies have shown that MYC-driven lymphomagenesis is associated with mammalian target of rapamycin (mTOR) activation and a MYC-evoked DNA damage response (DDR) transduced by phosphatidylinositol-3-kinase (PI3K)-related kinases (DNA-PK, ATM, and ATR). Here we report that BEZ235, a multitargeted pan-PI3K/dual-mTOR inhibitor, potently killed primary Myc-driven B-cell lymphomas and human cell lines bearing IG-cMYC translocations. Using pharmacologic and genetic dissection of PI3K/mTOR signaling, dual DDR/mTORC1 inhibition was identified as a key mediator of apoptosis. Moreover, apoptosis was initiated at drug concentrations insufficient to antagonize PI3K/mTORC2-regulated AKT phosphorylation. p53-independent induction of the proapoptotic BH3-only protein BMF was identified as a mechanism by which dual DDR/mTORC1 inhibition caused lymphoma cell death. BEZ235 treatment induced apoptotic tumor regressions in vivo that correlated with suppression of mTORC1-regulated substrates and reduced H2AX phosphorylation and also with feedback phosphorylation of AKT. These mechanistic studies hold important implications for the use of multitargeted PI3K inhibitors in the treatment of hematologic malignancies. In particular, the newly elucidated role of PI3K-related DDR kinases in response to PI3K inhibitors offers a novel therapeutic opportunity for the treatment of hematologic malignancies with an MYC-driven DDR.

[1]  S. Burma,et al.  The Dual PI 3 K / mTOR Inhibitor NVP-BEZ 235 Is a Potent Inhibitor of ATM-and DNA-PKCs-Mediated DNA Damage Responses 1 , 2 , 2014 .

[2]  C. Schmitt,et al.  mTORC1 induces apoptosis in MYC-driven B-cell lymphomas Combined inhibition of PI3K-related DNA damage response kinases and , 2013 .

[3]  L. Staudt,et al.  Concurrent expression of MYC and BCL2 in diffuse large B-cell lymphoma treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone. , 2012, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[4]  K. Young,et al.  Immunohistochemical double-hit score is a strong predictor of outcome in patients with diffuse large B-cell lymphoma treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone. , 2012, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[5]  S. Burma,et al.  The dual PI3K/mTOR inhibitor NVP-BEZ235 is a potent inhibitor of ATM- and DNA-PKCs-mediated DNA damage responses. , 2012, Neoplasia.

[6]  W. Sellers,et al.  Identification and Characterization of NVP-BKM120, an Orally Available Pan-Class I PI3-Kinase Inhibitor , 2011, Molecular Cancer Therapeutics.

[7]  B. Solomon,et al.  Inhibition of DNA-Dependent Protein Kinase Induces Accelerated Senescence in Irradiated Human Cancer Cells , 2011, Molecular Cancer Research.

[8]  C. Scott,et al.  Deciphering the molecular events necessary for synergistic tumor cell apoptosis mediated by the histone deacetylase inhibitor vorinostat and the BH3 mimetic ABT-737. , 2011, Cancer research.

[9]  B. Durkacz,et al.  Mitoxantrone in combination with an inhibitor of DNA‐dependent protein kinase: a potential therapy for high risk B‐cell chronic lymphocytic leukaemia , 2011, British journal of haematology.

[10]  T. Witzig,et al.  Signal transduction inhibitor therapy for lymphoma. , 2010, Hematology. American Society of Hematology. Education Program.

[11]  S. Lakhani,et al.  Harnessing the complexity of DNA-damage response pathways to improve cancer treatment outcomes , 2010, Oncogene.

[12]  J. McCubrey,et al.  Cancer esearch apeutics , Targets , and Chemical Biology ivity of the Novel Dual Phosphatidylinositol 3-Kinase / malian Target of Rapamycin Inhibitor NVP-BEZ 235 R inst T-Cell Acute Lymphoblastic Leukemia , 2010 .

[13]  L. Hengst,et al.  BH3-only protein Bmf mediates apoptosis upon inhibition of CAP-dependent protein synthesis , 2010, Cell Death and Differentiation.

[14]  D. Dittmer,et al.  Dual inhibition of PI3K and mTOR inhibits autocrine and paracrine proliferative loops in PI3K/Akt/mTOR-addicted lymphomas. , 2010, Blood.

[15]  T. Wirth,et al.  Advances in the understanding of MYC‐induced lymphomagenesis , 2010, British journal of haematology.

[16]  Da-Qing Yang,et al.  The ATM Inhibitor KU-55933 Suppresses Cell Proliferation and Induces Apoptosis by Blocking Akt In Cancer Cells with Overactivated Akt , 2010, Molecular Cancer Therapeutics.

[17]  S. Janz,et al.  NF-κB/STAT3/PI3K signaling crosstalk in iMycEμ B lymphoma , 2010, Molecular Cancer.

[18]  B. Coiffier,et al.  Phase III study to evaluate temsirolimus compared with investigator's choice therapy for the treatment of relapsed or refractory mantle cell lymphoma. , 2009, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[19]  N. Munshi,et al.  Antimyeloma activity of the orally bioavailable dual phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor NVP-BEZ235. , 2009, Cancer research.

[20]  D. Sabatini,et al.  DEPTOR Is an mTOR Inhibitor Frequently Overexpressed in Multiple Myeloma Cells and Required for Their Survival , 2009, Cell.

[21]  C. Chresta,et al.  Ku-0063794 is a specific inhibitor of the mammalian target of rapamycin (mTOR) , 2009, The Biochemical journal.

[22]  D. Sabatini,et al.  An ATP-competitive Mammalian Target of Rapamycin Inhibitor Reveals Rapamycin-resistant Functions of mTORC1* , 2009, Journal of Biological Chemistry.

[23]  M. Hall,et al.  The TSC-mTOR Pathway Mediates Translational Activation of TOP mRNAs by Insulin Largely in a Raptor- or Rictor-Independent Manner , 2009, Molecular and Cellular Biology.

[24]  Dexin Kong,et al.  Effect of ZSTK474, a novel phosphatidylinositol 3-kinase inhibitor, on DNA-dependent protein kinase. , 2009, Biological & pharmaceutical bulletin.

[25]  L. Penn,et al.  Reflecting on 25 years with MYC , 2008, Nature Reviews Cancer.

[26]  P. Pandolfi,et al.  Inhibition of mTORC1 leads to MAPK pathway activation through a PI3K-dependent feedback loop in human cancer. , 2008, The Journal of clinical investigation.

[27]  David E. Housman,et al.  mTORC1 promotes survival through translational control of Mcl-1 , 2008, Proceedings of the National Academy of Sciences.

[28]  Daniela Gabriel,et al.  Identification and characterization of NVP-BEZ235, a new orally available dual phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor with potent in vivo antitumor activity , 2008, Molecular Cancer Therapeutics.

[29]  E. Schmidt,et al.  c-myc Repression of TSC2 contributes to control of translation initiation and Myc-induced transformation. , 2007, Cancer research.

[30]  H. Stein,et al.  The Myc-evoked DNA damage response accounts for treatment resistance in primary lymphomas in vivo. , 2007, Blood.

[31]  Mark J. Smyth,et al.  Analysis of the apoptotic and therapeutic activities of histone deacetylase inhibitors by using a mouse model of B cell lymphoma , 2007, Proceedings of the National Academy of Sciences.

[32]  S. Lowe,et al.  Determinants of sensitivity and resistance to rapamycin-chemotherapy drug combinations in vivo. , 2006, Cancer research.

[33]  M. Henriksson,et al.  The Myc oncoprotein as a therapeutic target for human cancer. , 2006, Seminars in cancer biology.

[34]  Gordon B Mills,et al.  mTOR inhibition induces upstream receptor tyrosine kinase signaling and activates Akt. , 2006, Cancer research.

[35]  David M. Thomas,et al.  An in vivo tumor model exploiting metabolic response as a biomarker for targeted drug development. , 2005, Cancer research.

[36]  F. Khuri,et al.  Activation of Akt and eIF4E survival pathways by rapamycin-mediated mammalian target of rapamycin inhibition. , 2005, Cancer research.

[37]  D. Guertin,et al.  Phosphorylation and Regulation of Akt/PKB by the Rictor-mTOR Complex , 2005, Science.

[38]  T. Jacks,et al.  The Rb tumor suppressor is required for stress erythropoiesis , 2004, The EMBO journal.

[39]  P. Pandolfi,et al.  The translation factor eIF-4E promotes tumor formation and cooperates with c-Myc in lymphomagenesis , 2004, Nature Medicine.

[40]  P. Bouillet,et al.  Bim is a suppressor of Myc-induced mouse B cell leukemia. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[41]  S. Lowe,et al.  Survival signalling by Akt and eIF4E in oncogenesis and cancer therapy , 2004, Nature.

[42]  A. Borkhardt,et al.  Inactivation of the ARF–MDM-2–p53 pathway in sporadic Burkitt's lymphoma in children , 2004, Leukemia.

[43]  Andreas Villunger,et al.  p53- and Drug-Induced Apoptotic Responses Mediated by BH3-Only Proteins Puma and Noxa , 2003, Science.

[44]  M. S. Lewis,et al.  An international evaluation of CODOX-M and CODOX-M alternating with IVAC in adult Burkitt's lymphoma: results of United Kingdom Lymphoma Group LY06 study. , 2002, Annals of oncology : official journal of the European Society for Medical Oncology.

[45]  G. Wahl,et al.  c-Myc can induce DNA damage, increase reactive oxygen species, and mitigate p53 function: a mechanism for oncogene-induced genetic instability. , 2002, Molecular cell.

[46]  Andreas Villunger,et al.  Bmf: A Proapoptotic BH3-Only Protein Regulated by Interaction with the Myosin V Actin Motor Complex, Activated by Anoikis , 2001, Science.

[47]  M. Kastan,et al.  Participation of ATM in insulin signalling through phosphorylation of eIF-4E-binding protein 1 , 2000, Nature Cell Biology.

[48]  M. Roussel,et al.  Disruption of the ARF-Mdm2-p53 tumor suppressor pathway in Myc-induced lymphomagenesis. , 1999, Genes & development.

[49]  S. R. Datta,et al.  Akt Phosphorylation of BAD Couples Survival Signals to the Cell-Intrinsic Death Machinery , 1997, Cell.

[50]  K. Kohn,et al.  p53 gene mutations are associated with decreased sensitivity of human lymphoma cells to DNA damaging agents. , 1994, Cancer research.

[51]  R. Palmiter,et al.  The c-myc oncogene driven by immunoglobulin enhancers induces lymphoid malignancy in transgenic mice , 1985, Nature.

[52]  J. Corbin,et al.  Two classes of cAMP analogs which are selective for the two different cAMP-binding sites of type II protein kinase demonstrate synergism when added together to intact adipocytes. , 1984, The Journal of biological chemistry.