The role of polyamine catabolism in polyamine analogue-induced programmed cell death

Abstract

N 1 -ethyl-N 11 -[(cyclopropyl)methyl]-4,8,-diazaundecane (CPENSpm) is a polyamine analogue that represents a new class of antitumor agents that demonstrate phenotype-specific cytotoxic activity. However, the precise mechanism of its selective cytotoxic activity is not known. CPENSpm treatment results in the superinduction of the polyamine catabolic enzyme spermidine͞spermine N 1 -acetyltransferase (SSAT) in sensitive cell types and has been demonstrated to induce programmed cell death (PCD). The catalysis of polyamines by the SSAT͞polyamine oxidase (PAO) pathway produces H 2 O 2 as one product, suggesting that PCD produced by CPENSpm may be, in part, due to oxidative stress as a result of H 2 O 2 production. In the sensitive human nonsmall cell line H157, the coaddition of catalase significantly reduces high molecular weight (HMW) DNA (>50 kb) and nuclear fragmentation. Important to note, specific inhibition of PAO by N,N-bis(2,3-butadienyl)-1,4-butane-diamine results in a significant reduction of the formation of HMW DNA and nuclear fragmentation. In contrast, the coaddition of catalase or PAO inhibitor has no effect on reducing HMW DNA fragmentation induced by N 1 -ethyl-N 11 -[(cycloheptyl)methyl]-4,8,-diazaundecane, which does not induce SSAT and does not deplete intracellular polyamines. These results strongly suggest that H 2 O 2 production by PAO has a role in CPENSpm cytotoxicity in sensitive cells via PCD and demonstrate a potential basis for differential sensitivity to this promising new class of antineoplastic agents. Furthermore, the data suggest a general mechanism by which, under certain stimuli, cells can commit suicide through catabolism of the ubiquitous intracellular polyamines.Programmed cell death (PCD) is a fundamental biological regulatory mechanism involving selective cell deletion. It is an active and irreversible process in which cells activate the intrinsic death program for their own demise. PCD is absolutely required for the natural development and homeostasis of tissues in complex multicellular organisms (1-4). Morphological characteristics of PCD include cell shrinkage, nuclear condensation and fragmentation, plasma and nuclear membrane budding, and apoptotic bodies (3). PCD is biochemically characterized by activation of nucleases that cleave chromosomal DNA into high molecular weight (HMW) and͞or low molecular weight oligonucleosomal DNA fragments (5). PCD can be induced by normal physiological processes and by multiple nonphysiological stimuli, including oxidative stress and chemotherapeutic agents (4-7).The polyamines spermidine and spermine and their diamine precursor putrescine are intracellular cationic molecules that are essential for cell proliferation and differentiation (8, 9). The intracellular concentration of these ubiquitous molecules is highly regulated by the polyamine metabolic pathway, which influences the synthesis, degradation, uptake, and excretion of the cations (9). High ornithine decarboxylase (ODC) activity, the first rate-limiting step of polyami...

Polyamine-mediated Apoptosis of Alveolar Macrophages during Pneumocystis Pneumonia

“…This apoptosis is also characterized by mitochondrial damage and activation of caspase-9 (31,66), similar to what is seen in alveolar macrophages during Pcp. Polyamines can stimulate apoptosis of cells directly (32,34,35) or through the generation of ROS (67,68). Data of the current study suggest that polyamines induce apoptosis of alveolar macrophages via ROS during Pcp (Table 6).…”

Regulation of estrogenic and nuclear factor κB functions by polyamines and their role in polyamine analog-induced apoptosis of breast cancer cells

“…In our studies, polyamine analogs inhibited NRE-mediated transactivation. Polyamine analog treatment is also known to inhibit the polyamine biosynthetic enzyme, ornithine decarboxylase (ODC) (Porter et al, 1990), and induce the polyamine catabolic enzyme, SSAT (Casero and Pegg, 1993;Ha et al, 1997), thereby reducing the levels of the natural polyamines in the cells. Thus, it is possible that polyamine analogs, by decreasing intracellular spermine levels, inhibit the stimulus for sustained NF-kB activation.…”

“…Synthetic polyamine analogs, such as bis(ethyl)polyamines, have been shown to disrupt the natural polyamine pathway and lead to cell/tumor growth inhibition and apoptosis (Porter and Bergeron, 1988;Faaland et al, 2000;Marton and Pegg, 1995;McCloskey et al, 1996). In certain cell types, polyamine analogs cause a superinduction of spermidine/spermine N 1 -acetyltransferase (SSAT), a polyamine catabolizing enzyme Casero and Pegg, 1993;Ha et al, 1997). However, SSAT was not superinduced in MCF-7 breast cancer cells (Davidson et al, 1993;Faaland et al, 2000).…”

In vitro and in vivo effects of the conformationally restricted polyamine analogue CGC-11047 on small cell and non-small cell lung cancer cells

“…In addition to having the expected results of down-regulating biosynthesis, several analogues of spermine were found to have the unusual property of super-inducing the polyamine catabolic enzyme spermidine/spermine N 1 -acetyltransferase (SSAT) which results in the depletion of intracellular polyamines, inhibits cell growth, and in a tumor typespecific manner, induces apoptotic cell death [11,15,23,29,35,41]. N 1 .N 12 -Bisethylspermine (BESpm), a symmetrically substituted spermine analogue has been previously shown to induce SSAT to very high levels in numerous tumor cell types, leading to a rapid cytotoxic response of the cells.…”