Role Of S-adenosylmethionine Research Articles

The role of S-adenosyl methionine in preventing FOLFOX-induced liver toxicity: a retrospective analysis in patients affected by resected colorectal cancer treated with adjuvant FOLFOX regimen

Background: Hepatic toxicity is often related to chemotherapy agent administration, and it represents one of the principal causes of dose reduction and chemotherapy delays or discontinuation. S-Adenosyl methionine (AdoMet) supplementation is effective in the treatment of a variety of liver injuries, but it has never been evaluated in the prevention of chemotherapy-induced liver damage.Patients and methods: A total of 105 patients affected by resected colorectal cancer (CRC) were enrolled. Forty-five were treated with FOLFOX IV adjuvant regimen without administering AdoMet, 60 were treated with the same regimen plus supplementation with AdoMet. Liver enzyme levels were assessed before starting the treatment and every therapy cycle. Liver toxicity, chemotherapy course delays, discontinuations and dose reductions due to liver toxicity were recorded.Results: Aspartate aminotransferase (AST) (p < 0.001), alanine transaminase (ALT) (p = 0.003), bilirubin (p = 0.04) and gamma-glutamyltransferase (γ-GT) (p = 0.002) median level at the end of adjuvant therapy were significantly lower in patients treated with Adome. Patients supplemented with AdoMet experimented a lower grade of liver toxicity (p = 0.002) and had a reduced need of course delay (p < 0.0001) and dose reduction (p = 0.031).Conclusions: The results of our study demonstrate a protective effect of AdoMet supplementation in patients affected by resected CRC treated with FOLFOX IV adjuvant regimen.

Effect of S-adenosylmethionine on neointimal formation after balloon injury in obese diabetic rats

The association between hyperhomocysteinaemia and cardiovascular disease has been attributed to low levels of S-adenosylmethionine (SAM), a metabolic intermediate of homocysteine. However, the role of SAM in the development of restenosis has not been explored. Therefore, we investigated the effects of SAM on neointimal formation after balloon injury in obese diabetic rats and cultured cells. Otsuka Long-Evans Tokushima fatty rats were divided into the following three groups: control (normal saline); SAM15; and SAM30 (15 and 30 mg/kg per day, respectively; n = 10 per group). SAM was administered orally from 1 week before carotid injury to 2 weeks thereafter. SAM treatment for 3 weeks caused a significant dose-dependent reduction in the intima-to-media ratio. SAM treatment significantly reduced the proliferation of vascular smooth muscle cells (VSMCs) and induced more apoptosis than was observed in the control group. This effect was accompanied by reduced circulating levels of high-sensitivity C-reactive protein and monocyte chemoattractant protein-1, reduced urine 8-hydroxy-2'-deoxyguanosine (8-OHdG), and increased adiponectin. Intima-to-media ratio correlated significantly with the levels of inflammatory markers, adiponectin, and 8-OHdG. In vitro experiments demonstrated that VSMC proliferation and migration and the adhesion of monocytes decreased in response to SAM. SAM treatment also reduced tumour necrosis factor-α-induced reactive oxygen species and tunicamycin-induced GRP78 expression in VSMCs. These findings suggest that SAM exerts protective effects against restenosis after balloon injury in a rat model of type 2 diabetes by reducing the proliferation and inducing the apoptosis of VSMCs, modifying the inflammatory processes and reducing oxidative and endoplasmic reticulum stresses.

The role of S-adenosylmethionine in preventing oxaliplatin-induced liver toxicity: a retrospective analysis in metastatic colorectal cancer patients treated with bevacizumab plus oxaliplatin-based regimen

Hepatotoxicity represents a frequent chemotherapy-related side effect, often associated with course delays, discontinuations, and dose reductions. S-adenosylmethionine (AdoMet) administration is effective in the treatment of a variety of liver injuries, but it has never been evaluated in the prevention of chemotherapy-induced damage. Seventy-eight patients affected by metastatic colorectal cancer were enrolled. Forty-two patients were treated with bevacizumab and XELOX without administering AdoMet, 32 were treated with the same regimen plus supplementation with AdoMet. Liver enzymes levels were assessed before starting the treatment, and then every therapy cycle, liver toxicity, chemotherapy course delays, discontinuations, and dose reductions due to liver toxicity were recorded. Aspartate aminotransferase (P = 0.02), alanine transaminase (P < 0.001), lactate dehydrogenase (P = 0.008), total bilirubin (P = 0.03), and gamma-glutamyltransferase (P < 0.001) were found to be significantly lower in patients treated with AdoMet than in those who were not. Patients supplemented with AdoMet experimented a lower grade of liver toxicity (P = 0.009) and had a reduced need of course delay (P = 0.042) and dose reduction (P = 0.051). AdoMet supplementation in patients affected by metastatic colorectal cancer treated with oxaliplatin-based regimen seems to be effective in the prevention of chemotherapy-induced liver injury.

S-adenosylmethionine stimulates fatty acid metabolism-linked gene expression in porcine muscle satellite cells

Evidence indicates that both S-adenosylmethionine (SAMe) metabolism and intramuscular fat are associated with insulin resistance and type II diabetes. However, it is still unknown whether SAMe have effects on intramuscular adipogenesis. The present study investigated the roles of SAMe in the adipogenic differentiation of porcine muscle satellite cells. Cells isolated from neonatal pig muscle were treated with different concentrations of SAMe (0, 0.5 and 1.0 mM) for 24 h, induced for a 9-day adipogenic differentiation and were finally stained by oil red O staining. The adipocyte determination and differentiation factor-1 (ADD1) and peroxisome proliferator-activated receptor gamma (PPARγ) mRNA and protein were stimulated by SAMe treatment in a dose-dependent manner. Lipoprotein lipase (LPL) mRNA and protein were enhanced in 1.0 mM treatment group, compared with the control. No significant difference was observed in the intracellular lipid content among treatments. These results provide evidence that SAMe may be associated with intramuscular adipogenesis and indicate a novel action of SAMe in fat metabolism.

Role of S-adenosylmethionine as carcinogenic and/or co-carcinogenic factor in epigenetic silencing of tumour related genes in human lung

Role of S-adenosylmethionine as carcinogenic and/or co-carcinogenic factor in epigenetic silencing of tumour related genes in human lung

Possible Role of S-Adenosylmethionine, S-Adenosylhomocysteine, and Polyunsaturated Fatty Acids in Predementia Syndromes and Alzheimer's Disease

Very recent findings confirmed that S-adenosylmethionine (SAM) can exert a direct effect on glutathione S-transferase (GST) activity. Alzheimer's disease (AD) is accompanied by reduced GST activity, diminished SAM, and increased S-adenosyl homocysteine (SAH), the downstream metabolic product resulting from SAM-mediated transmethylation reactions, when deprived of folate. Therefore, these findings underscored the critical role of SAM in maintenance of neuronal health, suggesting a possible role of SAM as a neuroprotective dietary supplement in AD. Given recent findings from clinical trials in which omega-3 polyunsturated fatty acids (PUFA) supplementation was effective only in very mild AD subgroups or mild cognitive impairment (MCI), we suggest intervention trials using measures of dietary supplementation (dietary omega-3 PUFA and SAM plus B vitamin supplementation) to determine if such supplements will reduce the risk for cognitive decline in very mild AD and MCI. Therefore, key supplements are not necessarily working in isolation, and the most profound impact, or in some cases the only impact, is noted very early in the course of AD, suggesting that nutriceutical supplements may bolster pharmacological approaches well past the window where supplements can work on their own.

Potentiation of arsenic neurotoxicity by folate deprivation: Protective role of S-adenosyl methionine

Folate deficiency contributes to a variety of age-related neurological and psychological disorders including amyotrophic lateral sclerosis (ALS). The environmental neurotoxin arsenic has recently been linked with decreased neurofilament (NF) content in peripheral nerve. We examined herein, whether or not folate deprivation potentiated the impact of arsenic on NF dynamics. Arsenic inhibited translocation of NFs into axonal neurites in culture and increased perikaryal NF phosphoepitopes. Folate deprivation potentiated the impact of arsenic on these phenomena. Supplementation with S-adenosyl methionine (SAM) attenuated the impact of folate deprivation on arsenic neurotoxicity, consistent with the decrease in SAM following folate deprivation and the requirement for SAM-mediated methylation for arsenic bioelimination. These findings demonstrate how key nutritional deficiencies can potentiate the impact of enrivonmental neurotoxins.

Impaired liver regeneration in mice lacking methionine adenosyltransferase 1A.

Methionine adenosyltransferase (MAT) is an essential enzyme because it catalyzes the formation of S-adenosylmethionine (SAMe), the principal biological methyl donor. Of the two genes that encode MAT, MAT1A is mainly expressed in adult liver and MAT2A is expressed in all extrahepatic tissues. Mice lacking MAT1A have reduced hepatic SAMe content and spontaneously develop hepatocellular carcinoma. The current study examined the influence of chronic hepatic SAMe deficiency on liver regeneration. Despite having higher baseline hepatic staining for proliferating cell nuclear antigen, MAT1A knockout mice had impaired liver regeneration after partial hepatectomy (PH) as determined by bromodeoxyuridine incorporation. This can be explained by an inability to up-regulate cyclin D1 after PH in the knockout mice. Upstream signaling pathways involved in cyclin D1 activation include nuclear factor kappaB (NFkappaB), the c-Jun-N-terminal kinase (JNK), extracellular signal-regulated kinases (ERKs), and signal transducer and activator of transcription-3 (STAT-3). At baseline, JNK and ERK are more activated in the knockouts whereas NFkappaB and STAT-3 are similar to wild-type mice. Following PH, early activation of these pathways occurred, but although they remained increased in wild-type mice, c-jun and ERK phosphorylation fell progressively in the knockouts. Hepatic SAMe levels fell progressively following PH in wild-type mice but remained unchanged in the knockouts. In culture, MAT1A knockout hepatocytes have higher baseline DNA synthesis but failed to respond to the mitogenic effect of hepatocyte growth factor. Taken together, our findings define a critical role for SAMe in ERK signaling and cyclin D1 regulation during regeneration and suggest chronic hepatic SAMe depletion results in loss of responsiveness to mitogenic signals.

The mechanism of 7,8-diaminopelargonate synthase; the role of S-adenosylmethionine as the amino donor.

The product of the first transamination step in the reaction catalysed by diaminopelargonate (DAPA) synthase has been shown to be 4-(S-adenosyl)-2-oxobutanoate, which has been trapped as the corresponding alcohol.

The role of S-adenosylmethionine in the choline-deficient, ethionine supplemented diet model of pancreatitis

The role of S-adenosylmethionine in the choline-deficient, ethionine supplemented diet model of pancreatitis

The role of S-adenosylmethionine in the choline-deficient, ethionine supplemented diet model of pancreatitis

The role of S-adenosylmethionine in the choline-deficient, ethionine supplemented diet model of pancreatitis

Reduced mRNA abundance of the main enzymes involved in methionine metabolism in human liver cirrhosis and hepatocellular carcinoma: A novel role for S-adenosylmethionine

Reduced mRNA abundance of the main enzymes involved in methionine metabolism in human liver cirrhosis and hepatocellular carcinoma: A novel role for S-adenosylmethionine

Role of SAM-dependent thiol methylation in the renal toxicity of several solvents in mice.

The role of S-adenosylmethionine (SAM)-dependent thiol methylation in the nephrotoxicity of seven industrial solvents was studied in mice. The seven following solvents were utilized: bromobenzene (BB), styrene (STY), tetrachloroethylene (TTCE), trichloroethylene (TCE), 1,1-dichloroethylene (DCE), 1,2-dichloroethane (DCA) and hexachlorobutadiene (HCB). The experimental model comprised mice pretreated with periodate oxidized adenosine (ADOX) (100 micromol kg(-1) i.p.) 30 min before injection of solvents. In the first 4 h after ADOX treatment, the SAM levels were about fourfold higher than controls for the liver and kidney. The S-adenosylhomocysteine (SAH) levels were increased by factors of 11 and 14 and the SAM/SAH ratios were decreased by factors of 3 and 10 for the liver and kidney, respectively. These results show that ADOX treatment probably induces an inhibition of methyltransferase SAM-dependent in the liver and kidney and thus decreases the methylation capabilities. A single oral administration of BB (500 or 800 mg kg(-1)), TTCE (3500 or 4000 mg kg(-1)), TCE (3000 or 3500 mg kg(-1)) or STY (400 or 600 mg kg(-1)) did not induce renal toxicity, evaluated by the percentage of damaged tubules compared to controls. On the other hand, the three solvents DCE, HCB and DCA were nephrotoxic and the percentage of damaged tubules observed for each solvent was significantly different from the value of <1.8% for controls: 19% and 40% for DCE (130 and 200 mg kg(-1)), 50% and 46% for HCB (80 and 100 mg kg(-1)) and 5.1% and 7.6% for DCA (1000 and 1500 mg kg(-1)). The ADOX treatment in the mice did not modify the renal toxicity of the seven solvents. Thus, their renal toxicity, when it existed, was probably independent of the SAM-dependent thiolmethyltransferase activity in the mice. The results of this study are discussed from two viewpoints. The first concerns the general considerations on inhibition of thiol methyltransferase activities in mice and the second is related to the different solvents that are evoked individually.

The role and source of 5′-deoxyadenosyl radical in a carbon skeleton rearrangement catalyzed by a plant enzyme

The last step in the biosynthesis of tropane alkaloids is the carbon skeleton rearrangement of littorine to hyoscyamine. The reaction is catalyzed by a cell-free extract prepared from cultured hairy roots of Datura stramonium. Adenosylmethionine stimulated the rearrangement 10–20-fold and showed saturation kinetics with an apparent K m of 25 μM. It is proposed that S-adenosylmethionine is the source of a 5′-deoxyadenosyl radical which initiates the rearrangement in a similar manner as it does in analogous rearrangements catalyzed by coenzyme B 12-dependent enzymes. Possible roles of S-adenosylmethionine as a radical source in higher plants are discussed.

The role of S-adenosylmethionine in the lysine 2,3-aminomutase reaction.

The interconversion of L-lysine and L-3,6-diamino-hexanoate (L-beta-lysine) catalyzed by lysine 2,3-aminomutase is known to be stimulated by added S-adenosylmethionine (Chirpich, T. P., Zappia, V., Costilow, R. N., and Barker, H. A. (1970) J. Biol. Chem. 245, 1778-1789). In this paper we show that enzyme activated by S-[2,8,5'-3H]adenosylmethionine catalyzes the conversion of L-lysine to the equilibrium mixture of L-lysine and L-beta-lysine with incorporation of high levels of tritium into both isomers. The tritium levels in the isomers reflect the equilibrium constant for their interconversion, 84% in the L-beta-lysine and 16% in L-lysine compared with Keq = 5.3 +/- 0.3 in the direction of the formation of L-beta-lysine at pH 7.7 and 30 degrees C. No significant tritium is incorporated into lysine from S-[2,8-3H]adenosylmethionine or S-adenosyl[methyl-3H] methionine under comparable conditions. Therefore, the tritium incorporated into lysine in the former reaction arises from the 5'-position of the 5'-deoxyadenosyl group in S-adenosylmethionine. These experiments implicate the 5'-deoxyadenosyl portion of S-adenosylmethionine in the hydrogen transfer mechanism of this reaction, perhaps in a role analogous to that played by the 5'-deoxyadenosyl moiety of deoxyadenosyl cobalamin in coenzyme B12-dependent rearrangements.

S-adenosylmethionine inhibits collagen synthesis by human fibroblasts in vitro

Previous studies have indicated that S-adenosylmethionine (SAMe), the precursor of methyl groups and thiols, exerts an anti-inflammatory activity. In order to clarify whether this molecule also has antifibrotic properties, we evaluated its pharmacological effects on human fibroblasts in vitro. Accordingly, fibroblasts between 5 and 10 subcultures were incubated for 24 h with different SAMe concentrations (from 0.005 to 626 microM). Fibroblast proliferation measured by incorporation of labeled thymidine was not affected by SAMe in the range of the tested concentrations. Moreover, cell viability assessed by trypan-blue exclusion test was greater than 98% in all cultures, without any difference between SAMe and control cultures. Collagen synthesis estimated by HPLC measurement of hydroxyproline in both media and cells was not modified by SAMe concentrations lower than 0.05 microM. On the other hand, SAMe concentrations higher than 0.05 microM significantly (p less than 0.01) reduced collagen synthesis as compared with untreated controls. This effect was not dose-dependent. In conclusion, this study indicates that SAMe addition to fibroblasts in the range of concentrations which can be found in vivo induces a marked decrease (about 50% of control value) in collagen synthesis with no adverse effects on cell proliferation and viability. These findings suggest further investigation of the potential antifibrotic role of SAMe.

Role of S-adenosylmethionine in DNA synthesis and haemopoiesis.

In man, exposure to nitrous oxide (N2O) can produce neurological damage and megaloblastic change in the bone marrow due to inactivation of vitamin B12. Methionine metabolism is interrelated with that of vitamin B12 and folate; the effect of methionine on the impaired DNA synthesis produced by N2O was therefore studied in 17 patients undergoing surgery. 14 were anaesthetised with 50% N2O in oxygen for 3-24 h. The remaining 3 had been exposed to N2O for less than 3 h. All patients developed megaloblastic bone marrow change except 2 of the latter patients whose bone marrows remained normoblastic. The bone marrow was studied biochemically using the deoxyuridine (dU) suppression test. The in vitro addition of small doses of methionine was as effective as vitamin B12 itself in correcting the defective DNA synthesis produced by N2O. It is suggested that N2O impairs methionine biosynthesis, methionine, in the form of S-adenosylmethionine (SAM), being required for DNA synthesis and the prevention of the development of megaloblastic anaemia in man.

Determination of the metabolic origins of the sulfur and 3'-nitrogen atoms in biotin of Escherichia coli by mass spectrometry.

Two steps in the biosynthesis of biotin in Escherichia coli, incorporation of the nitrogen atom of methionine into 7-keto-8-aminopelargonic acid and of the sulfur atom into dethiobiotin, were examined. Sulfur and nitrogen metabolism were monitored by gas chromatography-mass spectrometry of volatile derivatives of internal (protein-bound) amino acids and excreted biotin. We were able to show that internal cysteine and excreted biotin were labeled to the same extent with 34S from either of two exogenous sulfur sources, 34SO4(2)-or L-[sulfane-34S]thiocystine. Internal methionine was eliminated from consideration, while cysteine, or possibly a closely related intermediate, was implicated as providing the sulfur atom for biotin biosynthesis. Also, in experiments designed to follow the metabolism of the nitrogen atom of methionine, it was found that biotin excreted into the culture medium by this organism grown with 95 atom % [15N]methionine contained greater than 70 atom % excess 15N in one of the nitrogens over that obtained from cultures grown with methionine of natural abundance 15N. These results provide evidence for the direct transfer of the methionine nitrogen as the role of S-adenosylmethionine in the conversion of 7-keto-8-aminopelargonic acid to 7,8-diaminopelargonic acid.

The role of S-adenosylmethionine in the cleavage of deoxyribonucleic acid by the restriction endonuclease from Escherichia coli K

The restriction endonuclease from Escherichia coli K specifically cleaves foreign DNA in the presence of S-adenosylmethionine, ATP, and Mg2+. The role of S-adenosylmethionine in this reaction has been studied by following the specific binding of the enzyme to unmodified DNA. The results indicate that S-adenosylmethionine acts as an allosteric effector. However, the rate-limiting step in the activation of the enzyme is not the binding of the effector itself, but an event subsequent to it. The interaction of the S-adenosylmethionine with two mutant K restriction endonucleases isolated previously has also been investigated. One of them, which is defective in restriction, can be activated in a manner similar to the wild type enzyme, while the other one, which lacks both restriction and modification activities (due to a mutation in the subunit responsible for DNA recognition), shows no such effect.

Fermentation production of L-methionine and regulation of L-methionine biosynthesis in Corynebacterium glutamicum. IV. Isolation and characterization of S-adenosylmethionine-requiring mutants and role of S-adenosylmethionine in the regulation of methionine biosynthesis in Corynebacterium glutamic

Using a minimal medium containing a methionine analog together with a small amount of S-adenosylmethionine (SAM), many SAM requiring mutants which responded only to SAM and not to methionine, S-adenosylhomocysteine, or homocysteine were efficiently isolated from Corynebacterium glutamicum TLD-140 after mutagenesis. Among them, SAM-14 and SAM-19 selected from selenomethionine resistant mutants were subjected to further investigation. Both mutants were unable to grow in a minimal medium and had no detectable activity of SAM synthetase. Both mutants acquired higher resistance to methionine hydroxamate and ethionine as well as to selenomethionine than TLD-140 and produced l-methionine in a medium.Homoserine-O-transacetylase in SAM-19 was subject to full repression by the addition of excess SAM to the growth medium and was not repressed under SAM limitation, whereas addition of excess l-methionine under SAM limitation caused a partial repression of the enzyme. SAM synthetase as well as l-methionine biosyntheti...