Polyamines are essential metabolites present in all living organisms, and this subject has attracted the attention of researchers worldwide interested in defining their mode of action in the variable cell functions in which they are involved, from growth to development and differentiation. Although the mechanism of polyamine synthesis is almost universal, different biological groups show intere...

The growth-promoting polyamines are polybasic compounds that efficiently enter cancer cells by as yet incompletely defined mechanisms. Strategies to inhibit their internalization may have important implications in the management of tumor disease. Here, we show that cellular binding and uptake of polyamines are inhibited by a single chain variable fragment anti-heparan sulfate (HS) antibody. Pol...

Human promyelogenous leukaemic cells (HL-60) were treated with novel spermine analogue, ( S )- N (1)-(2-methyl-1-butyl)- N (11)-ethyl-4,8-diazaundecane (IPENSpm), and the effects on growth and intracellular polyamine metabolism were measured. IPENSpm was cytotoxic to these cells at concentrations greater than 2.5 microM. It induced apoptosis in a caspase-dependent manner and its toxicity profil...

To elucidate endogenous mechanisms underlying cerebral damage during ischemia, brain polyamine oxidase activity was measured in rats subjected to permanent occlusion of the middle cerebral artery. Brain polyamine oxidase activity was increased significantly within 2 h after the onset of ischemia in brain homogenates (15.8 +/- 0.9 nmol/h/mg protein) as compared with homogenates prepared from the...

The antizyme protein, Oaz1, regulates synthesis of the polyamines putrescine, spermidine and spermine by controlling stability of the polyamine biosynthetic enzyme, ornithine decarboxylase. Antizyme mRNA translation depends upon a polyamine-stimulated +1 ribosomal frameshift, forming a complex negative feedback system in which the translational frameshifting event may be viewed in engineering t...

Pneumocystis pneumonia (PcP) is the most common opportunistic disease in immunocompromised patients. Alveolar macrophages are responsible for the clearance of Pneumocystis organisms; however, they undergo a high rate of apoptosis during PcP due to increased intracellular polyamine levels. In this study, the sources of polyamines and mechanisms of polyamine increase and polyamine-induced apoptos...

The mechanism of transmembrane polyamine internalization in mammalian cells remains unknown. A novel fluorescent spermidine conjugate [Spd-C(2)-BODIPY; N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-propionyl)-N'-(S -[spermidine-(N(4)-ethyl)]thioacetyl)ethylenediamine] was synthesized from N(4)-(mercaptoethyl)spermidine by a simple, one-step coupling procedure. In Chinese-hamster ...

The polyamines (putrescine, spermidine, and spermine) are synthesized by almost all organisms and are universally required for normal growth. Ornithine decarboxylase (ODC), an initial enzyme of polyamine synthesis, is one of the most highly regulated enzymes of eucaryotic organisms. Unusual mechanisms have evolved to control ODC, including rapid, polyamine-mediated turnover of the enzyme and co...

Most tumors maintain elevated levels of polyamines to support their growth and survival. This study explores the anti-tumor effect of polyamine starvation via both inhibiting polyamine biosynthesis and blocking the upregulated import of polyamines into the tumor. We demonstrate that polyamine blockade therapy (PBT) co-treatment with both DFMO and a novel polyamine transport inhibitor, Trimer PT...

N1,N11-diethylnorspermine (DENSPM) is a polyamine analog that down-regulates polyamine biosynthesis and potently upregulates the polyamine catabolic enzyme spermidine/spermine N1-acetyltransferase (SSAT). In certain cells, such as SKMEL-28 human melanoma cells, induction of SSAT is associated with rapid apoptosis. In this study, we used small interfering RNA (siRNA) to examine the role of SSAT ...