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PRIMA-1MET induces nucleolar translocation of Epstein-Barr virus-encoded EBNA-5 protein

By György Stuber, Emilie Flaberg, Gabor Petranyi, Rita Ötvös, Nina Rökaeus, Elena Kashuba, Klas G Wiman, George Klein and Laszlo Szekely


The low molecular weight compound, PRIMA-1MET restores the transcriptional transactivation function of certain p53 mutants in tumor cells. We have previously shown that PRIMA-1MET induces nucleolar translocation of p53, PML, CBP and Hsp70. The Epstein-Barr virus encoded, latency associated antigen EBNA-5 (also known as EBNA-LP) is required for the efficient transformation of human B lymphocytes by EBV. EBNA-5 associates with p53-hMDM2-p14ARF complexes. EBNA-5 is a nuclear protein that translocates to the nucleolus upon heat shock or inhibition of proteasomes along with p53, hMDM2, Hsp70, PML and proteasome subunits. Here we show that PRIMA-1MET induces the nucleolar translocation of EBNA-5 in EBV transformed B lymphoblasts and in transfected tumor cells. The PRIMA-1MET induced translocation of EBNA-5 is not dependent on the presence of mutant p53. It also occurs in p53 null cells or in cells that express wild type p53. Both the native and the EGFP or DSRed conjugated EBNA-5 respond to PRIMA-1MET treatment in the same way. Image analysis of DSRed-EBNA-5 expressing cells, using confocal fluorescence time-lapse microscopy showed that the nucleolar translocation requires several hours to complete. FRAP (fluorescence recovery after photobleaching) and FLIP (fluorescence loss in photobleaching) measurements on live cells showed that the nucleolar translocation was accompanied by the formation of EBNA-5 aggregates. The process is reversible since the aggregates are dissolved upon removal of PRIMA-1MET. Our results suggest that mutant p53 is not the sole target of PRIMA-1MET. We propose that PRIMA-1MET may reversibly inhibit cellular chaperons that prevent the aggregation of misfolded proteins, and that EBNA-5 may serve as a surrogate drug target for elucidating the precise molecular action of PRIMA-1MET

Topics: Research
Publisher: BioMed Central
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Provided by: PubMed Central

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  1. (1991). A: Co-localization of the retinoblastoma protein and the Epstein-Barr virus-encoded nuclear antigen EBNA-5. Exp Cell Res
  2. (2008). Caron de Fromentel C: In vitro and in vivo cytotoxic effects of PRIMA-1 on Hepatocellular Carcinoma cells expressing mutant p53ser249. Carcinogenesis
  3. (1998). Current perspectives on the molecular pathogenesis of virus-induced cancers in human immunodeficiency virus infection and acquired immunodeficiency syndrome.
  4. (1995). E: The Epstein-Barr virus nuclear antigen leader protein associates with hsp72/hsc73. J Virol
  5. (1991). E: The Epstein-Barr virus nuclear protein encoded by the leader of the EBNA RNAs is important in B-lymphocyte transformation.
  6. (1991). Early events in Epstein-Barr virus infection of human B lymphocytes. Virology
  7. (2002). Epstein-Barr virus. Virus Res
  8. (2007). Hsp72 up-regulates Epstein-Barr virus EBNALP coactivation with EBNA2. Blood
  9. (2007). K: PRIMA1(MET) induces nucleolar accumulation of mutant p53 and PML nuclear body-associated proteins. Oncogene
  10. (1993). KG: EBNA5, an Epstein-Barr virus-encoded nuclear antigen, binds to the retinoblastoma and p53 proteins.
  11. (2002). KG: Mutant p53-dependent growth suppression distinguishes PRIMA-1 from known anticancer drugs: a statistical analysis of information in the National Cancer Institute database. Carcinogenesis
  12. (2003). KG: Small molecules that reactivate mutant p53.
  13. (1997). Kieff E: Epstein-Barr virus nuclear protein LP stimulates EBNA-2 acidic domain-mediated transcriptional activation.
  14. (2003). L: EBV-encoded EBNA-5 associates with P14ARF in extranucleolar inclusions and prolongs the survival of P14ARF-expressing cells.
  15. (2003). L: p14ARF induces the relocation of HDM2 and p53 to extranucleolar sites that are targeted by PML bodies and proteasomes. Mol Cancer
  16. (2001). L: Proteasome inhibitor induces nucleolar translocation of EpsteinBarr virus-encoded EBNA-5. J Gen Virol
  17. (2001). L: Proteins associated with the promyelocytic leukemia gene product (PML)-containing nuclear body move to the nucleolus upon inhibition of proteasome-dependent protein degradation. Proc Natl Acad Sci USA
  18. (1987). Monoclonal and polyclonal antibodies against Epstein-Barr virus nuclear antigen 5 (EBNA-5) detect multiple protein species in Burkitt's lymphoma and lymphoblastoid cell lines.
  19. (2006). Mougin C: Modulation of p53 transcriptional activity by PRIMA-1 and Pifithrin-alpha on staurosporine-induced apoptosis of wild-type and mutated p53 epithelial cells. Apoptosis
  20. (1992). PJ: Cell growth effects of Epstein-Barr virus leader protein.
  21. (1994). PJ: EBNA-2 and EBNA-LP cooperate to cause G0 to G1 transition during immortalization of resting human B lymphocytes by Epstein-Barr virus.
  22. (1995). Resting B-cells, EBV-infected Bblasts and established lymphoblastoid cell lines differ in their Rb, p53 and EBNA-5 expression patterns. Oncogene
  23. (2007). Restoration of Wild-Type p53 Function in Human Tumors: Strategies for Efficient Cancer Therapy. Adv Cancer Res
  24. (2008). RG: PRIMA-1(met) radiosensitizes prostate cancer cells independent of their MTp53-status. Radiother Oncol
  25. (1995). Ringertz N: Reversible nucleolar translocation of Epstein-Barr virusencoded EBNA-5 and hsp70 proteins after exposure to heat shock or cell density congestion.
  26. (2000). Selective depletion of heat shock protein 70 (Hsp70) activates a tumor-specific death program that is independent of caspases and bypasses Bcl-2. Proc Natl Acad Sci USA
  27. (2002). Selivanova G: Restoration of the tumor suppressor function to mutant p53 by a low-molecularweight compound. Nat Med
  28. (2005). SS: Proteomic identification of heat shock protein 90 as a candidate target for p53 mutation reactivation by PRIMA-1 in breast cancer cells. Breast Cancer Res
  29. (2006). Strategies for therapeutic targeting of the p53 pathway in cancer. Cell Death Differ
  30. (1996). The Epstein-Barr virus-encoded nuclear antigen EBNA-5 accumulates in PML-containing bodies.
  31. (2008). Vojtesek B: Chaperonedependent stabilization and degradation of p53 mutants. Oncogene
  32. (2001). Wawrzynow A: Hsp70 interactions with the p53 tumour suppressor protein. Embo J
  33. (2003). Wiman KG: Novel cancer therapy by reactivation of the p53 apoptosis pathway. Ann Med
  34. (2007). Wiman KG: Reactivation of mutant p53: molecular mechanisms and therapeutic potential. Oncogene

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