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  • Title: PUMA overexpression induces reactive oxygen species generation and proteasome-mediated stathmin degradation in colorectal cancer cells.
    Author: Liu Z, Lu H, Shi H, Du Y, Yu J, Gu S, Chen X, Liu KJ, Hu CA.
    Journal: Cancer Res; 2005 Mar 01; 65(5):1647-54. PubMed ID: 15753358.
    Abstract:
    Increased amounts of reactive oxygen species (ROS) induce apoptosis in mammalian cells. PUMA (P53 up-regulated modulator of apoptosis), a mitochondrial proapoptotic BH3-only protein, induces rapid apoptosis through a Bax- and mitochondria-dependent pathway. However, the molecular basis of PUMA-induced apoptosis is largely not understood. Using a combination of biophysical and biochemical methods and PUMA-inducible colorectal cells, DLD-1.PUMA, we showed that (a) PUMA-induced apoptosis is dose and time dependent; (b) PUMA-induced apoptosis is directly associated with ROS generation; (c) diphenyleneiodonium chloride, a ROS blocker, or BAX-inhibiting peptide, a suppressor of BAX translocation, decreased ROS generation and apoptosis in DLD-1.PUMA cells; (d) overexpression of PUMA induced up-regulation (>1.34-fold) of peroxiredoxin 1 and down-regulation (by 25%) of stathmin through proteasome-mediated degradation; and (e) hydrogen peroxide down-regulated stathmin and disrupted the cellular microtubule network. Our findings indicate that PUMA induces apoptosis, in part, through the BAX-dependent generation of superoxide and hydrogen peroxide. ROS overproduction and oxidative stress induce proteome-wise alterations, such as stathmin degradation and disorganization of the cell microtubule network, in apoptotic cells.
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