HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 282, Issue 48, 34700-34706, November 30, 2007

This Article Abstract Full Text (PDF) All Versions of this Article: 282/48/34700    most recent M704282200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hyvönen, M. T. Articles by Jänne, J. Search for Related Content PubMed PubMed Citation Articles by Hyvönen, M. T. Articles by Jänne, J. Social Bookmarking                      What's this?

Role of Hypusinated Eukaryotic Translation Initiation Factor 5A in Polyamine Depletion-induced Cytostasis^*

Mervi T. Hyvönen¹, Tuomo A. Keinänen¹, Marc Cerrada-Gimenez, Riitta Sinervirta, Nikolay Grigorenko², Alex R. Khomutov, Jouko Vepsäläinen^¶, Leena Alhonen, and Juhani Jänne³

From the A. I. Virtanen Institute for Molecular Sciences and the ^¶Department of Chemistry, University of Kuopio, P. O. Box 1627, FI-70211 Kuopio, Finland and the Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 117984, Russia

Received for publication, May 24, 2007 , and in revised form, September 27, 2007.

	ABSTRACT

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS DISCUSSION REFERENCES

 
We have earlier shown that -methylated spermidine and spermine analogues rescue cells from polyamine depletion-induced growth inhibition and maintain pancreatic integrity under severe polyamine deprivation. However, because -methylspermidine can serve as a precursor of hypusine, an integral part of functional eukaryotic translation initiation factor 5A required for cell proliferation, and because , -bismethylspermine can be converted to methylspermidine, it is not entirely clear whether the restoration of cell growth is actually attributable to hypusine formed from these polyamine analogues. Here, we have used optically active isomers of methylated spermidine and spermine and show that polyamine depletion-induced acute cytostasis in cultured cells could be reversed by all the isomers of the methylpolyamines irrespective of whether they served or not as precursors of hypusine. In transgenic rats with activated polyamine catabolism, all the isomers similarly restored liver regeneration and reduced plasma -amylase activity associated with induced pancreatitis. Under the above experimental conditions, the (S, S)- but not the (R, R)-isomer of bismethylspermine was converted to methylspermidine apparently through the action of spermine oxidase strongly preferring the (S, S)-isomer. Of the analogues, however, only (S)-methylspermidine sustained cell growth during prolonged (more than 1 week) inhibition of polyamine biosynthesis. It was also the only isomer efficiently converted to hypusine, indicating that deoxyhypusine synthase likewise possesses hidden stereospecificity. Taken together, the results show that growth inhibition in response to polyamine depletion involves two phases, an acute and a late hypusine-dependent phase.

	INTRODUCTION

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS DISCUSSION REFERENCES

 
A large number of studies have indicated that a continuous supply of the polyamines (spermidine and spermine) is required for animal cell proliferation to occur as polyamine depletion resulted either from a specific inhibition of their biosynthesis (1) or from an activation of their catabolism (2) invariably leads to growth inhibition. The molecular mechanisms involved in the requirement of polyamines for animal cell growth are largely unknown besides the fact that spermidine, but not spermine, serves as the sole biosynthetic precursor for hypusine, an unusual amino acid that is an integral component of eukaryotic translation initiation factor 5A (eIF5A)⁴ (3). Because functional (hypusinated) eIF5A is required for animal cell growth (4, 5), it is often difficult to judge whether spermidine depletion-induced growth inhibition is secondary to hypusine deprivation. The finding that cytostasis resulting from an inhibition of S-adenosylmethionine decarboxylase in cultured cells is reversed by -methylspermidine (MeSpd) but not by , -bismethylspermine (Me₂Spm) indicates that growth inhibition was attributable to hypusine depletion as MeSpd, but not Me₂Spm, can serve as the biosynthetic precursor for hypusine formation (6). On the other hand, MeSpd and both singly and doubly methylated spermine derivatives appear to reverse growth inhibition by 2-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase, in cultured cells (6, 7). In support of the notion that spermidine and spermine are exchangeable in maintaining cell growth, we found that Me₂Spm, as effectively as MeSpd, reversed DFMO-induced cytostasis in cultured cells under conditions where the oxidation of spermine was totally blocked (7). Moreover, we obtained evidence indicating that Me₂Spm can overcome the proliferative block of early liver regeneration and prevent the development of polyamine depletion-induced acute pancreatitis in transgenic rats overexpressing spermidine/spermine N¹-acetyltransferase (SSAT) (7, 8). However, because racemic Me₂Spm is converted to MeSpd, at least in some cell types (like hepatocytes) (7), it is not clear whether the growth inhibition is actually due to hypusine depletion.

We have now synthesized and used pure stereoisomers of MeSpd and especially of Me₂Spm as surrogates for the natural polyamines under experimental conditions where the pools of spermidine and/or spermine were profoundly depleted. The application of these analogues allowed the discrimination of hypusine-independent and hypusine-dependent phases of polyamine depletion-induced cytostasis. Hence, the optical isomers of -methylated polyamines turned out to be useful tools to investigate cellular effects of spermidine and spermine.

	EXPERIMENTAL PROCEDURES

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS DISCUSSION REFERENCES

 
Chemicals—The synthesis of optically active (R)- and (S)-isomers of MeSpd and all stereoisomers (R,R, S,S, and R,S) of Me₂Spm has been described recently (9). The -methylated polyamine analogues and their isomers showed purity greater than 99.5% according to ¹H/¹³C NMR data and high performance liquid chromatography analysis. [methyl-³H]Thymidine (specific radioactivity 71.2 Ci/mmol) was purchased from PerkinElmer Life Sciences. [¹⁴C]Spm (110 mCi/mmol) was from Amersham Biosciences.

Animals and Cell Cultures—The generation of transgenic rats harboring mouse metallothionein I promoter-driven SSAT transgene has been described earlier (10). Partial hepatectomy of the rats was performed according to the original method of Higgins and Anderson (11). Acute pancreatitis in the SSAT transgenic rats was induced with zinc as described in Alhonen et al. (10). The animal experiments were approved by the Animal Care and Use Committee of the University of Kuopio and the provincial government. The prostate carcinoma cell lines, DU145 and LNCaP, were obtained from ATCC. The cells were grown in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum and 50 µg/ml gentamycin under conditions of +37 °C and 10% CO₂. To determine the ability of the stereoisomers of MeSpd and Me₂Spm to reverse DFMO-induced growth inhibition, the cells were plated (1 x 10⁶ cells/10 cm plate) and incubated overnight, after which the medium was replaced with fresh medium containing DFMO (5 mM) and polyamine analogue (100 µM). The cells were then harvested by trypsinization, electronically counted (Coulter Counter model Z1), and passaged (2 x 10⁶ cells/10-cm plate) every 3 days until day 12. The content of DFMO and analogues was maintained with each passage.

Analytical Methods—Ornithine decarboxylase (12) and SSAT (13) activities were assayed according to published methods. High performance liquid chromatography was used to determine the natural polyamines and their methylated derivatives essentially as described earlier (14). Immunohistochemical analysis of proliferating cell nuclear antigen (PCNA) was carried out as described earlier (15). eIF5A was measured by two-dimensional gel electrophoresis followed by immunoblotting as previously described (16, 17). The antibody against eIF5A was purchased from BD Biosciences. The gels were blotted onto an Immobilon FL membrane (Millipore). The membranes were scanned with a Typhoon Variable Mode Imager (GE Healthcare). Lysates from cells treated with 400 µML-mimosine (an inhibitor of deoxyhypusine hydroxylase) or 50 µM GC7 (N¹-guanyl-1,7-diaminoheptane, an inhibitor of deoxyhypusine synthase) for 24 h were used as references. -Amylase activity was measured from rat plasma using Microlab 200 (Merck) analyzer and Ecoline S⁺ reagent based on CNP-G3 method (DiaSys Diagnostic Systems GmbH).

Enzyme Kinetic Analyses with Human Recombinant SMO—Human recombinant SMO was prepared as described earlier (7) except omitting the affinity purification step with polyamine-conjugated Sepharose. The kinetic studies were carried out twice with triplicates at five different (5–100 µM) substrate concentrations in 100 mM glycine-NaOH at pH 9.5 containing 5 mM dithiothreitol. Enzyme stock solution was diluted with 50 mM sodium phosphate buffer (pH 8.0) containing 0.1% Triton-X-100 before kinetic studies to yield 0.1–4.0 µg/10 µl of SMO for each reaction mixture. Reactions were carried out and analyzed as described earlier (7).

SMO Activity Assay—The reaction mixture (180 µl) contained 100 mM glycine-NaOH (pH 9.5), 5 mM dithiothreitol, 0.1 mM pargyline, 1.0 mM semicarbazide, cell lysate (100 µg of total protein), and 250 µM [¹⁴C]spermine (30 mCi/mmol). The reaction mixture, without [¹⁴C]spermine, was preincubated at +37 °C for 10 min, and further incubation with [¹⁴C]spermine was performed for 1 h. The reaction was terminated with 20 µl of 50% sulfosalicylic acid containing 100 µM diaminoheptane and centrifuged at 12,000 x g for 30 min. Polyamines were separated using high performance liquid chromatography, fractions were collected at 1-min intervals, and radioactivity of each fraction was measured using liquid scintillation counter. The blank (without cell lysate) and the reaction mixture containing 100 µM MDL 72527 (polyamine oxidase/SMO inhibitor) were used as controls for determining background activity and specificity of reaction.

Statistical Analyses—The data are expressed as the mean ± S.D. One-way analysis of variance with Dunnett's or Bonferroni's post hoc tests was used for multiple comparisons with the aid of a software package, GraphPad Prism 4.0 (GraphPad Software, Inc., San Diego, CA). The same software package was used for the analyses of enzyme kinetic data using Michaelis-Menten equation with nonlinear fitting.

	RESULTS

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS DISCUSSION REFERENCES

 
The Methylated Polyamine Derivatives Rescue Cells from Difluoromethylornithine-induced Growth Inhibition—As depicted in Fig. 1, A and B, all the stereoisomers of MeSpd and Me₂Spm equally effectively rescued DU145 prostate carcinoma cells from DFMO-induced growth inhibition. Similarly, all the isomers of Me₂Spm reversed the cytostasis caused by the drug in LNCaP cells with little differences between individual isomers (Fig. 1C). However, as indicated in the insets (panels B and C), an interesting difference existed between the Me₂Spm stereoisomers, as only the (S,S)-isomer, but not the (R,R) isomer, appeared to be converted to MeSpd in both cell types.

Restoration of Early Liver Regeneration in Transgenic Rats with Activated Polyamine Catabolism by the Analogues—Partial hepatectomy of transgenic rats overexpressing SSAT under the metallothionein promoter leads to delayed liver regeneration due to striking induction of the transgene in response to the operation (15). The failure to initiate regeneration is in all likelihood attributable to the profoundly reduced hepatic spermidine and spermine pools as the regeneration can be restored in the transgenic animals by a prior administration of MeSpd or Me₂Spm (7, 18). Fig. 2 depicts the results of an experiment where racemic MeSpd and (R,R)- and (S,S)-isomers of Me₂Spm were tested for their capacity to restore liver regeneration in the transgenic animals. As indicated in the figure, partial hepatectomy resulted in a marked enhancement of thymidine incorporation in the livers of wild-type animals at 24 h after the operation, whereas in the transgenic animals it remained at the low preoperative level. Racemic MeSpd and the (R,R)- and (S,S)-isomers of Me₂Spm given before the operation fully restored DNA synthesis in the transgenic animals (Fig. 2A). As in the case of the prostate cancer cell lines, only the (S,S)-isomer of Me₂Spm was converted to MeSpd in the liver (Table 1).

View larger version (19K): [in this window] [in a new window]   FIGURE 1. Rescue from DFMO-induced growth inhibition by isomers of -methylated spermidine and spermine analogues. The cells were grown for 3 days in the absence or presence of 5 mM DFMO and 100 µM analogue. A, DU145 prostate cancer cells grown in the presence of DFMO and isomers of MeSpd. B, DU145 cells grown in the presence of DFMO and isomers of Me2Spm. The inset shows the conversion of different isomers of Me2Spm to MeSpd (pmol/µg DNA). C, LNCaP prostate cancer cells grown in the presence of DFMO and isomers of Me2Spm. The inset shows the conversion of different isomers of Me2Spm to MeSpd (pmol/µg DNA). D, DFMO; Rac, racemic: **, p < 0.01 as compared with DFMO alone. Data are the means ± S.D. of triplicate cultures.

View larger version (34K): [in this window] [in a new window]   FIGURE 2. Effect of MeSpd (racemic) and (S, S)- and (R, R)-isomers of Me2Spm on thymidine incorporation and PCNA expression at 24 h after partial hepatectomy of wild-type and transgenic rats overexpressing SSAT. The animals received 50 mg/kg of racemic MeSpd or 25 mg/kg of the isomers of Me2Spm intraperitoneally at 20 h and 4 h before the operation. A, relative [3H]thymidine incorporation. B, PCNA labeling index, % of total cells. Linear (C) and nonlinear (Boltzmann sigmoidal) (D) regression analysis of the correlation between PCNA-positive cells and total polyamines in regenerating rat liver. C, control; R, regenerating; R,R and S,S refer to the isomers of Me2Spm. p < 0.01 (**) and p < 0.001 (***) as compared with control livers (wild type or transgenic). Data are the means ± S.D., three to five animals in a group.

As indicated in Fig. 2C, a close and highly significant correlation existed between PCNA-positive cells and the concentration of total polyamines (the natural and the analogues) in the regenerating liver. Interestingly, when nonlinear fitting (Boltzmann sigmoidal) (Fig. 2D) was used, it appeared that there was a sharp threshold (about 1000 pmol/mg) in the concentration of total polyamines, after which PCNA-positive cells started to appear.

View larger version (21K): [in this window] [in a new window]   FIGURE 3. Effect of MeSpd (racemic) and (S, S)- and (R, R)-isomers of Me2Spm on plasma -amylase activity at 24 h after zinc induction of acute pancreatitis in transgenic rats overexpressing SSAT. The animals received 50 mg/kg of MeSpd or 25 mg/kg of the isomers of Me2Spm intraperitoneally at 20 and 4 h before the induction of pancreatitis with zinc (10 mg of zinc/kg intraperitoneal Me2Spm). The inset shows the pancreatic conversion of the isomers of Me2Spm to MeSpd (pmol/mg tissue). *, p < 0.05 as compared with control animals. U/I, specific activity determination.

Long-term Inhibition of Polyamine Biosynthesis in Cultured Cells—We next tested the ability of the analogues to maintain cellular growth during prolonged inhibition of polyamine biosynthesis in cultured DU145 cells. As shown in Table 2, DFMO efficiently depleted intracellular putrescine and spermidine and also reduced spermine levels. As depicted in Fig. 4, treatment with DFMO resulted in growth arrest, whereas all the stereoisomers of MeSpd and Me₂Spm were able to maintain a near normal growth rate in the presence of DFMO during the first 6 days. Beyond this time point only (S)-MeSpd effectively sustained cell growth. The (S,S)-isomer supported growth better than the other Me₂Spm isomers, and it was the only isomer converted to MeSpd.

Stereoisomers of Me₂Spm as Substrates for Spermine Oxidase—As shown in Table 3, (S,S)-Me₂Spm served as an excellent substrate for human recombinant SMO (in fact, according to k_cat/K_m value, even better than the natural substrate spermine) being nearly 500-fold more efficient substrate than the (R,R)-stereoisomer. The basal spermine oxidase activity in DU145 cells was 431 ± 92 pmol/mg/h.

	DISCUSSION

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS DISCUSSION REFERENCES

The unique function of spermidine serving as the sole biosynthetic precursor of hypusine, an unusual amino acid covalently bound to eIF5A (3), has created problems in assessing the role of the polyamines in growth promotion, as hypusinated eIF5A is critically required for animal cell proliferation (5). Hypusinated eIF5A appears to have a number of vital functions such as association with translating ribosomes (22), regulation of mRNA stability, and involvement in the process called nonsense-mediated mRNA decay (23) as well as control of p53-mediated apoptosis (24). A recent report likewise indicates that hypusinated eIF5A promotes neurite outgrowth and survival (25). Some studies have suggested that growth inhibition resulting from reduced spermidine pools would be secondary to hypusine depletion (26), whereas others indicate that polyamine depletion-associated early cytostasis occurs in the absence of a depletion of hypusinated eIF5A (17). Similarly, our previous studies, based on the use of methylated spermine derivatives, have suggested that polyamine depletion-induced acute antiproliferative effect is attributable to the reduced pools of spermidine and spermine per se (7).

View larger version (24K): [in this window] [in a new window]   FIGURE 4. Support of long-term growth of DU145 prostate cancer cells cultured in the presence of DFMO by isomers of MeSpd and Me2Spm. The cells were cultured in the presence of 5 mM DFMO for 3, 6, 9, and 12 days with or without 100 µM stereoisomers of MeSpd and Me2Spm. Cells were counted and passaged at same density every 3 days. D, DFMO.

View larger version (27K): [in this window] [in a new window]   FIGURE 5. Effect of the stereoisomers of MeSpd (A) and Me2Spm (B) on the level of hypusinated eIF5A in DU145 prostate cancer cells. Treatments are as in Fig. 4. DU145 cell lysates (25 µg of total protein on each gel) were separated by two-dimensional gel electrophoresis followed by detection with immunoblotting of eIF5A. Acetylated eIF5A precursor, eIF5A precursor, and hypusinated eIF5A are shown. Samples are from 12-day cultures, except DFMO, which was from 9 days. The control in panels A and B is from the same sample. The molecular size of eIF5A is 18 kDa.

Growth inhibition achieved by DFMO, an inhibitor of ornithine decarboxylase, is more rapid than that obtained by AbeAdo, an inhibitor of S-adenosyl-L-methionine decarboxylase. DFMO depletes putrescine and spermidine but does not usually affect spermine level, whereas AbeAdo depletes spermidine and spermine, but there is also a compensatory increase in putrescine level. Byers et al. (26) suggested that the greatly elevated putrescine could support cellular functions of polyamines until hypusinated eIF5A becomes depleted. However, as shown by our present results (Table 1, Fig. 2), the increased putrescine level was not sufficient to support hepatic proliferation in rats with activated polyamine catabolism.

The mechanism of the acute growth inhibition caused by polyamine depletion is not well elucidated, but it may be related to the function of the replication machinery. Fredlund and Oredsson (28) showed that polyamine-depleted Chinese hamster ovary cells entered the S phase of cell cycle at normal rate, but the progression through the S phase was delayed. Depletion of putrescine and spermidine pools was accompanied by impaired DNA replication, whereas no changes occurred in the rate of RNA and protein synthesis. In an earlier study, polyamine supplementation at the time of S-phase initiation in synchronized HeLa cells restored DNA synthesis, with a lag of 3–6 h (29). On the other hand, some studies indicate that polyamine depletion causes G₁ arrest (30).

Interestingly, the synthesis of deoxyhypusinated eIF5A appears to be stereospecific as only the (S)-isomer of MeSpd is used as a substrate. On the contrary, S-isomers of branched-chain derivatives of 1,7-diaminoheptane seem to have less activity in comparison to their racemic forms, but their unsaturated S-isomer derivatives display higher activity in comparison to their racemic forms (31).

A further interesting feature of the present results is the finding that also the oxidation of Me₂Spm appears to be stereospecific to the (S,S)-isomer. We recently reported that mammalian polyamine oxidase, normally using achiral substrates, displays cryptic stereospecificity when -methylated polyamines are used as the substrates (32, 33). In fact, the latter results (33) indicate that polyamine oxidase has a k_cat/K_m value (efficiency of the enzyme catalysis) for the (S,S)-isomer of Me₂Spm that is nearly 30 times higher than that for the (R,R)-isomer. However, this difference may not be practically relevant as non-acetylated polyamines are poor substrates for mammalian polyamine oxidase in the absence of aldehydes. It is much more likely that the methylated spermine derivatives are oxidized in vivo by the recently discovered SMO, the natural substrate for which is spermine (34, 35). Because SMO specifically cleaves spermine to spermidine, it is tempting to speculate that it has evolved in animal cells to secure a continuous supply of spermidine for the synthesis of hypusine. This view is nicely supported by recent experiments with Saccharomyces cerevisiae cells lacking both spermidine synthase and FMS1-encoded amine oxidase (yeast counterpart of SMO oxidizing spermine to spermidine). The mutated yeast cells showed an absolute requirement for spermidine, not replaceable by spermine, for their growth, as in the absence of the amine oxidase spermine is not converted to spermidine required for hypusine biosynthesis (36).

	FOOTNOTES

 
^* This work was supported in part by grants from the Academy of Finland and from the Finnish Cancer Organizations. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ Both authors contributed equally to the work.

² Present address: Dept. of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland.

³ To whom correspondence should be addressed. Tel.: 358-17-163049; Fax: 358-17-163025; E-mail: Juhani.Janne{at}uku.fi.

⁴ The abbreviations used are: eIF5A, eukaryotic translation initiation factor 5A; DFMO, 2-difluoromethylornithine; MeSpd, -methylspermidine; Me₂Spm, , -bismethylspermine; PCNA, proliferating cell nuclear antigen; SMO, spermine oxidase; SSAT, spermidine/spermine N¹-acetyltransferase; AbeAdo, 5'-([(Z)-4-amino-2-butenyl]methylamino)-5'-deoxyadenosine (MDL 73811).

	ACKNOWLEDGMENTS

 
We thank Tuula Reponen, Anne Karppinen, and Sisko Juutinen for skilful technical assistance. The plasmid encoding human spermine oxidase was kindly provided by Dr. Carl W. Porter (Roswell Park Cancer Institute, Buffalo, NY). We also thank Dr. Anne Uimari (at this Institute) for assistance with the production of the recombinant spermine oxidase.

	REFERENCES

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS DISCUSSION REFERENCES

 

1. Thomas, T., and Thomas, T. J. (2003) J. Cell. Mol. Med. 7, 113–126[Medline] [Order article via Infotrieve]
2. Jänne, J., Alhonen, L., Pietilä, M., Keinänen, T. A., Uimari, A., Hyvönen, M. T., Pirinen, E., and Järvinen, A. (2006) J. Biochem. (Tokyo) 139, 155–160[Abstract/Free Full Text]
3. Park, M. H., Cooper, H. L., and Folk, J. E. (1981) Proc. Natl. Acad. Sci. U. S. A. 78, 2869–2873[Abstract/Free Full Text]
4. Park, M. H., Wolff, E. C., Lee, Y. B., and Folk, J. E. (1994) J. Biol. Chem. 269, 27827–27832[Abstract/Free Full Text]
5. Park, M. H., Wolff, E. C., and Folk, J. E. (1993) Trends Biochem. Sci. 18, 475–479[CrossRef][Medline] [Order article via Infotrieve]
6. Byers, T. L., Lakanen, J. R., Coward, J. K., and Pegg, A. E. (1994) Biochem. J. 303, 363–368[Medline] [Order article via Infotrieve]
7. Järvinen, A., Grigorenko, N., Khomutov, A. R., Hyvönen, M. T., Uimari, A., Vepsäläinen, J., Sinervirta, R., Keinänen, T. A., Vujcic, S., Alhonen, L., Porter, C. W., and Jänne, J. (2005) J. Biol. Chem. 280, 6595–6601[Abstract/Free Full Text]
8. Hyvönen, M. T., Herzig, K. H., Sinervirta, R., Albrecht, E., Nordback, I., Sand, J., Keinänen, T. A., Vepsäläinen, J., Grigorenko, N., Khomutov, A. R., Krüger, B., Jänne, J., and Alhonen, L. (2006) Am. J. Pathol. 168, 115–122[Abstract/Free Full Text]
9. Grigorenko, N. A., Khomutov, A. R., Keinänen, T. A., Järvinen, A., Alhonen, L., Jänne, J., and Vepsäläinen, J. (2007) Tetrahedron 63, 2257–2263[CrossRef]
10. Alhonen, L., Parkkinen, J. J., Keinänen, T., Sinervirta, R., Herzig, K. H., and Jänne, J. (2000) Proc. Natl. Acad. Sci. U. S. A. 97, 8290–8295[Abstract/Free Full Text]
11. Higgins, G. H., and Anderson, R. M. (1931) Arch. Pathol. 12, 186–202
12. Jänne, J., and Williams-Ashman, H. G. (1971) J. Biol. Chem. 246, 1725–1732[Abstract/Free Full Text]
13. Bernacki, R. J., Oberman, E. J., Seweryniak, K. E., Atwood, A., Bergeron, R. J., and Porter, C. W. (1995) Clin. Cancer Res. 1, 847–857[Abstract]
14. Hyvönen, T., Keinänen, T. A., Khomutov, A. R., Khomutov, R. M., and Eloranta, T. O. (1992) J. Chromatogr. 574, 17–21[Medline] [Order article via Infotrieve]
15. Alhonen, L., Räsänen, T. L., Sinervirta, R., Parkkinen, J. J., Korhonen, V. P., Pietilä, M., and Jänne, J. (2002) Biochem. J. 362, 149–153[CrossRef][Medline] [Order article via Infotrieve]
16. Taylor, C. A., Sun, Z., Cliche, D. O., Ming, H., Eshaque, B., Jin, S., Hopkins, M. T., Thai, B., and Thompson, J. E. (2007) Exp. Cell Res. 313, 437–449[CrossRef][Medline] [Order article via Infotrieve]
17. Nishimura, K., Murozumi, K., Shirahata, A., Park, M. H., Kashiwagi, K., and Igarashi, K. (2005) Biochem. J. 385, 779–785[CrossRef][Medline] [Order article via Infotrieve]
18. Räsänen, T. L., Alhonen, L., Sinervirta, R., Keinänen, T., Herzig, K. H., Suppola, S., Khomutov, A. R., Vepsäläinen, J., and Jänne, J. (2002) J. Biol. Chem. 277, 39867–39872[Abstract/Free Full Text]
19. Keinänen, T. A., Järvinen, A., Uimari, A., Vepsäläinen, J., Khomutov, A. R., Grigorenko, N., Hyvönen, M. T., Cerrada-Gimenez, M., Alhonen, L., and Jänne, J. (2007) Mini Rev. Med. Chem. 7, 813–820[CrossRef][Medline] [Order article via Infotrieve]
20. Lakanen, J. R., Coward, J. K., and Pegg, A. E. (1992) J. Med. Chem. 35, 724–734[CrossRef][Medline] [Order article via Infotrieve]
21. Varnado, B. L., Voci, C. J., Meyer, L. M., and Coward, J. K. (2000) Bioorg. Chem. 28, 395–408[CrossRef][Medline] [Order article via Infotrieve]
22. Jao, D. L., and Chen, K. Y. (2006) J. Cell. Biochem. 97, 583–598[CrossRef][Medline] [Order article via Infotrieve]
23. Schrader, R., Young, C., Kozian, D., Hoffmann, R., and Lottspeich, F. (2006) J. Biol. Chem. 281, 35336–35346[Abstract/Free Full Text]
24. Li, A. L., Li, H. Y., Jin, B. F., Ye, Q. N., Zhou, T., Yu, X. D., Pan, X., Man, J. H., He, K., Yu, M., Hu, M. R., Wang, J., Yang, S. C., Shen, B. F., and Zhang, X. M. (2004) J. Biol. Chem. 279, 49251–49258[Abstract/Free Full Text]
25. Huang, Y., Higginson, D. S., Hester, L., Park, M. H., and Snyder, S. H. (2007) Proc. Natl. Acad. Sci. U. S. A. 104, 4194–4199[Abstract/Free Full Text]
26. Byers, T. L., Ganem, B., and Pegg, A. E. (1992) Biochem. J. 287, 717–724[Medline] [Order article via Infotrieve]
27. Bergeron, R. J., Weimar, W. R., Muller, R., Zimmerman, C. O., McCosar, B. H., Yao, H., and Smith, R. E. (1998) J. Med. Chem. 41, 3901–3908[CrossRef][Medline] [Order article via Infotrieve]
28. Fredlund, J. O., and Oredsson, S. M. (1996) Eur. J. Biochem. 237, 539–544[Medline] [Order article via Infotrieve]
29. Gallo, C. J., Koza, R. A., and Herbst, E. J. (1986) Biochem. J. 238, 37–42[Medline] [Order article via Infotrieve]
30. Kramer, D. L., Chang, B. D., Chen, Y., Diegelman, P., Alm, K., Black, A. R., Roninson, I. B., and Porter, C. W. (2001) Cancer Res. 61, 7754–7762[Abstract/Free Full Text]
31. Lee, Y. B., and Folk, J. E. (1998) Bioorg. Med. Chem. 6, 253–270[CrossRef][Medline] [Order article via Infotrieve]
32. Järvinen, A. J., Cerrada-Gimenez, M., Grigorenko, N. A., Khomutov, A. R., Vepsäläinen, J. J., Sinervirta, R. M., Keinänen, T. A., Alhonen, L. I., and Jänne, J. (2006) J. Med. Chem. 49, 399–406[CrossRef][Medline] [Order article via Infotrieve]
33. Järvinen, A., Keinänen, T. A., Grigorenko, N. A., Khomutov, A. R., Uimari, A., Vepsäläinen, J., Alhonen, L., and Jänne, J. (2006) J. Biol. Chem. 281, 4589–4595[Abstract/Free Full Text]
34. Wang, Y., Devereux, W., Woster, P. M., Stewart, T. M., Hacker, A., and Casero, R. A., Jr. (2001) Cancer Res. 61, 5370–5373[Abstract/Free Full Text]
35. Vujcic, S., Diegelman, P., Bacchi, C. J., Kramer, D. L., and Porter, C. W. (2002) Biochem. J. 367, 665–675[CrossRef][Medline] [Order article via Infotrieve]
36. Chattopadhyay, M. K., Tabor, C. W., and Tabor, H. (2003) Proc. Natl. Acad. Sci. U. S. A. 100, 13869–13874[Abstract/Free Full Text]

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				A. E. Pegg Spermidine/spermine-N1-acetyltransferase: a key metabolic regulator Am J Physiol Endocrinol Metab, June 1, 2008; 294(6): E995 - E1010. [Abstract] [Full Text] [PDF]

				M. K. Chattopadhyay, M. H. Park, and H. Tabor Hypusine modification for growth is the major function of spermidine in Saccharomyces cerevisiae polyamine auxotrophs grown in limiting spermidine PNAS, May 6, 2008; 105(18): 6554 - 6559. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) All Versions of this Article: 282/48/34700    most recent M704282200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hyvönen, M. T. Articles by Jänne, J. Search for Related Content PubMed PubMed Citation Articles by Hyvönen, M. T. Articles by Jänne, J. Social Bookmarking                      What's this?