BACKGROUND: Transformed phenotypes are common to cell lines derived from various cancers. Proteome profiling is a valuable tool that may reveal uncharacteristic cell phenotypes in transformed cells. Changes in expression of glutathione S-transferases (GSTs) and other proteins interacting with glutathione (GSH) in model cell lines could be of particular interest. METHODS: We compared the phenotypes of breast cell lines EM-G3, HCC1937, MCF7 and MDA-MB-231 using 2-D electrophoresis (2-DE). We further separated GSH-binding proteins from the cell lines using affinity chromatography with GSH-Sepharose 4B, performed 2-DE analysis and identified the main protein spots. RESULTS: Correlation coefficients among 2-DE gels from the cell lines were lower than 0.65, pointing to dissimilarity among the cell lines. Differences in primary constituents of the cytoskeleton were shown by the 2-D protein maps and western blots. The spot patterns in gels of GSH-binding fractions from primary carcinoma-derived cell lines HCC1937 and EM-G3 were similar to each other, and they differed from the spot patterns of cell lines MCF7 and MDA-MB-231 that were derived from pleural effusions of metastatic mammary carcinoma patients. Major differences in the expression of GST P1-1 and carbonyl reductase [NADPH] 1 were observed among the cell lines, indicating differential abilities of the cell lines to metabolize xenobiotics. CONCLUSIONS: Our results confirmed the applicability of targeted affinity chromatography to proteome profiling and allowed us to characterize the phenotypes of four breast cancer cell lines.

• MeSH
• Electrophoresis, Gel, Two-Dimensional MeSH
• Alcohol Oxidoreductases metabolism   MeSH
• Capecitabine MeSH
• Chromatography, Affinity MeSH
• Cisplatin administration & dosage   MeSH
• Deoxycytidine administration & dosage   analogs & derivatives   MeSH
• Adult MeSH
• Phenotype MeSH
• Fluorouracil administration & dosage   analogs & derivatives   MeSH
• Glutathione S-Transferase pi metabolism   MeSH
• Carboplatin administration & dosage   MeSH
• Colorectal Neoplasms drug therapy   metabolism   pathology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Survival Rate MeSH
• Head and Neck Neoplasms drug therapy   metabolism   pathology   MeSH
• Lung Neoplasms drug therapy   metabolism   pathology   MeSH
• Breast Neoplasms drug therapy   metabolism   pathology   MeSH
• Neurophysiology MeSH
• Organoplatinum Compounds administration & dosage   MeSH
• Oxaliplatin MeSH
• Paclitaxel administration & dosage   MeSH
• Antineoplastic Combined Chemotherapy Protocols therapeutic use   MeSH
• Aged MeSH
• Case-Control Studies MeSH
• Treatment Outcome MeSH
• Blotting, Western MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Alcohol Oxidoreductases MeSH
• Capecitabine MeSH
• CBR1 protein, human MeSH Browser
• Cisplatin MeSH
• Deoxycytidine MeSH
• Fluorouracil MeSH
• Glutathione S-Transferase pi MeSH
• GSTP1 protein, human MeSH Browser
• Carboplatin MeSH
• Organoplatinum Compounds MeSH
• Oxaliplatin MeSH
• Paclitaxel MeSH

Betaine-homocysteine S-methyltransferase (BHMT) catalyzes the transfer of a methyl group from betaine to l-homocysteine, yielding dimethylglycine and l-methionine. In this study, we prepared a new series of BHMT inhibitors. The inhibitors were designed to mimic the hypothetical transition state of BHMT substrates and consisted of analogues with NH, N(CH(3)), or N(CH(3))(2) groups separated from the homocysteine sulfur atom by a methylene, ethylene, or a propylene spacer. Only the inhibitor with the N(CH(3)) moiety and ethylene spacer gave moderate inhibition. This result led us to prepare two inhibitors lacking a nitrogen atom in the S-linked alkyl chain: (RS,RS)-5-(3-amino-3-carboxypropylthio)-3-methylpentanoic acid and (RS)-5-(3-amino-3-carboxypropylthio)-3,3-dimethylpentanoic acid. Both of these compounds were highly potent inhibitors of BHMT. The finding that BHMT does not tolerate a true betaine mimic within these inhibitors, especially the nitrogen atom, is surprising and evokes questions about putative conformational changes of BHMT upon the binding of the substrates/products and inhibitors.

• MeSH
• Betaine-Homocysteine S-Methyltransferase antagonists & inhibitors   MeSH
• Homocysteine analogs & derivatives   chemical synthesis   chemistry   pharmacology   MeSH
• Enzyme Inhibitors chemical synthesis   chemistry   pharmacology   MeSH
• Pentanoic Acids chemical synthesis   chemistry   pharmacology   MeSH
• Humans MeSH
• Molecular Structure MeSH
• Drug Design MeSH
• Stereoisomerism MeSH
• Structure-Activity Relationship MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• 5-(3-amino-3-carboxypropylthio)-3-methylpentanoic acid MeSH Browser
• 5-(3-amino-3-carboxypropylthio)-3,3-dimethylpentanoic acid MeSH Browser
• Betaine-Homocysteine S-Methyltransferase MeSH
• Homocysteine MeSH
• Enzyme Inhibitors MeSH
• Pentanoic Acids MeSH

A series of S-alkylated derivatives of homocysteine were synthesized and characterized as inhibitors of human recombinant betaine-homocysteine S-methyltransferase (BHMT). Some of these compounds inhibit BHMT with IC50 values in the nanomolar range. BHMT is very sensitive to the structure of substituents on the sulfur atom of homocysteine. The S-carboxybutyl and S-carboxypentyl derivatives make the most potent inhibitors, and an additional sulfur atom in the alkyl chain is well tolerated. The respective (R,S)-5-(3-amino-3-carboxy-propylsulfanyl)-pentanoic, (R,S)-6-(3-amino-3-carboxy-propylsulfanyl)-hexanoic, and (R,S)-2-amino-4-(2-carboxymethylsulfanyl-ethylsulfanyl)-butyric acids are very potent inhibitors and are the strongest ever reported. We determined that (R,S)-5-(3-amino-3-carboxy-propylsulfanyl)-pentanoic acid displays competitive inhibition with respect to betaine binding with a Kappi of 12 nM. Some of these compounds are currently being tested in mice to study the influence of BHMT on the metabolism of sulfur amino acids in vivo.

• MeSH
• Betaine-Homocysteine S-Methyltransferase antagonists & inhibitors   chemistry   MeSH
• Butyrates chemical synthesis   chemistry   MeSH
• Homocysteine analogs & derivatives   chemical synthesis   chemistry   MeSH
• Caproates chemical synthesis   chemistry   MeSH
• Pentanoic Acids chemical synthesis   chemistry   MeSH
• Humans MeSH
• Stereoisomerism MeSH
• Sulfides chemical synthesis   chemistry   MeSH
• Structure-Activity Relationship MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• 2-amino-4-(2-carboxymethylsulfanylethylsulfanyl)butyric acid MeSH Browser
• 5-(3-amino-3-carboxypropylsulfanyl)pentanoic acid MeSH Browser
• 6-(3-amino-3-carboxypropylsulfanyl)hexanoic acid MeSH Browser
• Betaine-Homocysteine S-Methyltransferase MeSH
• BHMT protein, human MeSH Browser
• Butyrates MeSH
• Homocysteine MeSH
• Caproates MeSH
• Pentanoic Acids MeSH
• Sulfides MeSH