Spermine oxidase SMO(PAOh1), not N1-acetylpolyamine oxidase PAO, is the primary source of cytotoxic H2O2 in polyamine analogue-treated human breast cancer cell lines
Spermine oxidase SMO(PAOh1), not N1-acetylpolyamine oxidase PAO, is the primary source of cytotoxic H2O2 in polyamine analogue-treated human breast cancer cell lines
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DOI：
10.1074/jbc.m508177200
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发表时间：
2005-12-02
影响因子：
4.8
通讯作者：
Casero, RA
中科院分区：
文献类型：
--
作者：
Pledgie, A;Huang, Y;Casero, RA
多胺催化剂的诱导及其H2 O2的产生与特异性抗肿瘤多胺类似物的反应有关。最初的假设是，类似物诱导的限速亚精胺/精胺N-1-乙酰基转移酶（SSAT）提供底物的过氧化物酶体乙酰多胺氧化酶（PAO），导致在多胺池减少，通过catalysts，氧化和排泄的乙酰化多胺和有毒的醛和H2 O2的生产。然而，最近发现的诱导型精胺氧化酶SMO（PAOh 1）建议的可能性，原来的假设可能是不完整的。为了研究分解代谢酶在乳腺癌细胞对多胺类似物N-1，N（1-）双（乙基）去甲精胺（BENSpm）的反应中的作用，使用了稳定的敲低小干扰RNA策略。BENSpm在几种乳腺癌细胞系中差异诱导SSAT和SMO（PAOh 1）mRNA和活性，而未检测到N-1-乙酰多胺氧化酶PAO mRNA或活性。BENSpm治疗抑制细胞生长，降低细胞内多胺水平，并降低鸟氨酸脱羧酶活性在所有细胞系检查。SSAT或SMO（PAOh 1）的稳定敲除降低了MDA-MB-231细胞对BENSpm的敏感性，而双敲除的MDA-MB-231细胞几乎完全抵抗类似物的生长抑制作用。此外，通过BENSpm诱导的多胺催化剂产生的H2 O2被认为是完全来自SMO（PAOh 1）的活动，而不是通过PAO活性乙酰化多胺。这些数据表明，SSAT和SMO（PAOh 1）活动是乳腺肿瘤细胞对BENSpm的细胞反应的主要介质，而PAO在这种反应中起很小或没有作用。
The induction of polyamine catabolism and its production of H2O2 have been implicated in the response to specific antitumor polyamine analogues. The original hypothesis was that analogue induction of the rate-limiting spermidine/spermine N-1-acetyltransferase (SSAT) provided substrate for the peroxisomal acetylpolyamine oxidase (PAO), resulting in a decrease in polyamine pools through catabolism, oxidation, and excretion of acetylated polyamines and the production of toxic aldehydes and H2O2. However, the recent discovery of the inducible spermine oxidase SMO(PAOh1) suggested the possibility that the original hypothesis may be incomplete. To examine the role of the catabolic enzymes in the response of breast cancer cells to the polyamine analogue N-1, N(1-)bis(ethyl) norspermine (BENSpm), a stable knockdown small interfering RNA strategy was used. BENSpm differentially induced SSAT and SMO(PAOh1) mRNA and activity in several breast cancer cell lines, whereas no N-1-acetylpolyamine oxidase PAO mRNA or activity was detected. BENSpm treatment inhibited cell growth, decreased intracellular polyamine levels, and decreased ornithine decarboxylase activity in all cell lines examined. The stable knockdown of either SSAT or SMO(PAOh1) reduced the sensitivity of MDA-MB-231cells to BENSpm, whereas double knockdown MDA-MB-231 cells were almost entirely resistant to the growth inhibitory effects of the analogue. Furthermore, the H2O2 produced through BENSpm-induced polyamine catabolism was found to be derived exclusively from SMO(PAOh1) activity and not through PAO activity on acetylated polyamines. These data suggested that SSAT and SMO(PAOh1) activities are the major mediators of the cellular response of breast tumor cells to BENSpm and that PAO plays little or no role in this response.