p8/nupr1 regulates DNA-repair activity after double-strand gamma irradiation-induced DNA damage

INSERM U.624, Stress Cellulaire, Case 915, Parc Scientifique et Technologique de Luminy, Marseille Cedex 9, France.
Journal of Cellular Physiology (Impact Factor: 3.87). 12/2009; 221(3):594-602. DOI: 10.1002/jcp.21889
Source: PubMed

ABSTRACT The stress protein p8 is a small, highly basic, unfolded, and multifunctional protein. We have previously shown that most of its functions are exerted through interactions with other proteins, whose activities are thereby enhanced or repressed. In this work we describe another example of such mechanism, by which p8 binds and negatively regulates MSL1, a histone acetyl transferase (HAT)-associated protein, which in turn binds the DNA-damage-associated 53BP1 protein to facilitate DNA repair following DNA gamma-irradiation. Contrary to the HAT-associated activity, MSL1-dependent DNA-repair activity is almost completely dependent on 53BP1 expression. The picture that has emerged from our findings is that 53BP1 could be a scaffold that gets the HAT MSL1-dependent DNA-repair activity to the sites of DNA damage. Finally, we also found that, although p8 expression is transiently activated after gamma-irradiation, it is eventually submitted to sustained down-regulation, presumably to allow development of MSL1-associated DNA-repair activity. We conclude that interaction of MSL1 with 53BP1 brings MSL1-dependent HAT activity to the vicinity of damaged DNA. MSL1-dependent HAT activity, which is negatively regulated by the stress protein p8, induces chromatin remodeling and relaxation allowing access to DNA of the repair machinery.

Download full-text


Available from: Meritxell Gironella, Apr 10, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: NUPR1 (nuclear protein 1) was found to play a key role in the development of several malignancies including pancreas, breast, and prostate cancers. However, the functional role of NUPR1 in nonsmall cell lung cancer (NSCLC) progression and development is little known. Here, lentivirus-mediated small interfering RNA (siRNA) was employed to downregulate endogenous NUPR1 expression to study the function of NUPR1 in growth of nonsmall cell lung cancer. A lentivirus-mediated RNAi technology was used to specifically knock down the expression of NUPR1 in H1299 cells. Quantitative real-time reverse transcriptase polymerase chain reaction, flow cytometry, western blot and cell count assays were studied to characterize NUPR1 expression in vitro. Furthermore, nonsmall cell lung cancer xenograft models in nude mice were established to investigate whether knockdown of NUPR1 reduces the tumor growth in vivo. We found that downregulation of NUPR1 expression significantly inhibited nonsmall cell lung cancer H1299 cells proliferation and colony formation in vitro. Moreover, the specific downregulation of NUPR1 arrested cells in G0 phase of cell cycle and increased apoptosis rate. Silencing of NUPR1 also suppressed tumor growth by tail vein injection of lentivirus encoded shRNA against NUPR1 in vivo. Our findings revealed that the NUPR1 gene represents a promising target for gene silencing therapy in nonsmall cell lung cancer. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
    The Anatomical Record Advances in Integrative Anatomy and Evolutionary Biology 12/2012; 295(12). DOI:10.1002/ar.22571 · 1.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: p8 (NUPR1 (nuclear protein-1), Com1 (candidate of metastasis-1)) is a protein related to the high mobility group of transcriptional regulators. It is a key player in the cellular stress response and is involved in metastasis. p8 was first identified as a gene induced in pancreatitis but has been since found overexpressed in several cancers and pathological conditions. Despite its small size and apparently simple structure, p8 functions in several biochemical and genetic pathways, and its expression is crucial for in vivo metastasis in mice, for cytokine induction of metalloproteases, and for stress-induced cardiomyocyte hypertrophy. Understanding p8 functions will provide new opportunities for developing more effective therapeutic approaches to cancer and cardiovascular diseases.
    Journal of Biological Chemistry 11/2009; 285(3):1577-81. DOI:10.1074/jbc.R109.080887 · 4.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In spite of the great advances made on the knowledge of cancer etiology and the significant breakthroughs in terms of treatment, complete remission is obtained in only around half of cancer patients. In fact, therapies that appear successful for some cancers are totally unfruitful for others, and some cancer types still remain incurables. In order to develop new therapies suitable to these tenacious cancers, we need to renew our view on cancer and to revise some old paradigms and "false friends" that can hide unexpected new therapeutic targets. A good example of these paradigms is the role of the cell stress response in tumor progression. Indeed, a number of studies has been devoted to the pivotal tumor suppressor function of some players of this response, of which the p53 protein is the best example. Nevertheless, during tumor progression and metastasis, the cancer cell faces many stresses imposed by tumor microenvironment and its survival will be conditioned by an efficient cell stress response. This review is consecrated to the role played by a pivotal actor of the cell stress response, the p8 protein, during carcinogenesis. We will recapitulate the data available on its different cell functions and the assets p8 confer to the cancer cell in terms of growth, drugs resistance and metastasis formations.
    Pathologie Biologie 11/2009; 59(6):303-8. DOI:10.1016/j.patbio.2009.10.001 · 1.07 Impact Factor