Metabolic Stability of α-Methylated Polyamine Derivatives and Their Use as Substitutes for the Natural Polyamines

Abstract

Metabolically stable polyamine derivatives may serve as useful surrogates for the natural polyamines in studies aimed to elucidate the functions of individual polyamines. Here we studied the metabolic stability of ␣-methylspermidine, ␣-methylspermine, and bis-␣-methylspermine, which all have been reported to fulfill many of the putative physiological functions of the natural polyamines. In vivo studies were performed with the transgenic rats overexpressing spermidine/spermine N 1 -acetyltransferase. ␣-Methylspermidine effectively accumulated in the liver and did not appear to undergo any further metabolism. On the other hand, ␣-methylspermine was readily converted to ␣-methylspermidine and spermidine; similarly, bis-␣-methylspermine was converted to ␣-methylspermidine to some extent, both conversions being inhibited by the polyamine oxidase inhibitor N 1 ,N 2 -bis(2,3-butadienyl)-1,4-butanediamine. Furthermore, we used recombinant polyamine oxidase, spermidine/spermine N 1 -acetyltransferase, and the recently discovered spermine oxidase in the kinetic studies. In vitro studies confirmed that methylation did not protect spermine analogs from degradation, whereas the spermidine analog was stable. Both ␣-methylspermidine and bis-␣-methylspermine overcame the proliferative block of early liver regeneration in transgenic rats and reversed the cytostasis induced by an inhibition of ornithine decarboxylase in cultured fetal fibroblasts.Although the requirement of the natural polyamines spermidine, spermine, and their precursor putrescine for the growth of mammalian cells is extremely well documented, their specific functions in proliferative processes are largely unknown (1). Some of the published data appear to assign a central role to spermidine, whereas putrescine is supposed to serve as its precursor and spermine as a storage pool convertible back to spermidine. For the elucidation of the physiological roles of individual polyamines, metabolically stable derivatives of polyamines fulfilling their specific cellular functions would be extremely valuable. Methyl derivatives of spermidine and spermine have been used as substitutes for the natural polyamines both in vitro and in vivo. ␣-Methylspermidine (MeSpd), 1 ␣-methylspermine (MeSpm), and bis-␣-methylspermine (1,12-dimethylspermine, Me 2 Spm) are equally effective as the natural polyamines in inducing the conversion of right-handed B-DNA to left-handed Z-DNA (2). In addition to spermidine and spermine, cytostasis that resulted from the inhibition of the S-adenosylmethionine decarboxylase can be reversed by MeSpd but not by Me 2 Spm (3). Spermidine, spermine (because of its conversion to spermidine), and MeSpd serve as substrates for the synthesis of deoxyhypusine (an integral part of eukaryotic initiation factor 5A), whereas Me 2 Spm does not (3). Interestingly, all of the mentioned methylated derivatives of spermidine and spermine have been reported to reverse the cytostasis induced by difluoromethylornithine, a specific inhibitor of mammalian ornithine decarboxyl...

Detection and Adaptation in Parasitic Angiosperm Host Selection

“…Production is tightly regulated by the presence of xenognostic quinines [9], which may be due to a reduction in the expression of a ROS-producing catalyst. Likely candidates for this catalyst in plants include xanthine oxidases [25], peroxidases [26], lipoxygenases [27], polyamine oxidases [28], mitochondrial NADH dehydrogenases [29], oxalate oxidases [30], and NADPH oxidases [31]- [33]. The SSH library identified two peroxidases (13 and 15) and one NADPH oxidase (10) down regulated by DMBQ exposure during pre-commitment (0.5 h, stages I) and transition (2 -6 h, stage II).…”

Polyamine-regulated unproductive splicing and translation of spermidine/spermine N1-acetyltransferase

“…Me 2 Spm is a metabolically stable analog of spermine being capable to fulfill most of the putative functions of natural spermine. Moreover, it is resistant toward serum amine oxidase and thus may be used without aminoguanidine supplement (Lakanen et al 1992;Yang et al 1995;Järvinen et al 2005).…”

Guide Molecule-driven Stereospecific Degradation of α-Methylpolyamines by Polyamine Oxidase

“…Syntheses of (R)-AcMeSpd, (S)-AcMeSpd, both isomers of MeSpm, and all diastereomers of Me 2 Spm were performed using the same (R)-and (S)-N 1 -(o-nitrophenylsulfonyl)-N 3 -(tert-butyloxycarbonyl)-1,3-diaminobutane as the key chiral intermediates, which, after alkylation with appropriate halides and removal of the protecting groups, afforded the target isomers of ␣-methylated analogs. Both racemic ␣-methylated polyamine analogs and their isomers showed purity of Ͼ99.5% according to 1 H/ 13 C NMR data and HPLC analysis. A preformed adduct of spermine with PL (PLϭSpm) was prepared as described in Ref.…”

“…The interaction of racemic MeSpd with recombinant human PAO (hPAO) in the presence of benzaldehyde (BA), which allows the enzyme to oxidize nonacetylated Spd, led to the formation of putrescine (13). This prompted us to study the effect of aldehydes on this reaction using recently synthesized isomers of MeSpd and ␣-methylspermine (MeSpm) as well as the three diastereomers of Me 2 Spm (Fig.…”

“…Both MeSpd and Me 2 Spm are capable of preventing acute pancreatitis and restoring early liver regeneration after partial hepatectomy under the condition of severe depletion of the natural polyamines in transgenic rats (12,13).…”