The relation between blood taurine (2-aminoethanesulfonic acid) concentrations and obesity was investigated. Taurine is supplied to the body by dietary ingestion as well as by de novo synthesis; it is anabolized by cysteine dioxygenase (CDO), which is abundantly expressed in liver and white adipose tissue. Overexpression of CDO in 3T3-L1 preadipocytes caused a decrease in the level of cysteine (precursor of taurine) and an increase in the level of taurine in the culture medium, suggesting that CDO is involved in biosynthesis and secretion of taurine in white adipose tissue. In high-fat diet-induced and/or genetically obese mice, a decrease in the blood taurine concentration was observed along with a decrease in CDO expression in adipose tissue but not in liver. Dietary taurine supplementation prevented high-fat diet-induced obesity with increased resting energy expenditure. Thus, taurine deficiency observed in association with obesity may create a vicious circle promoting obesity. Dietary taurine supplementation interrupts this vicious circle and may prevent obesity.

Keywords: flavonoids/heat shock proteins/human cancer cell lines ABSTRACT. Cells exposed to several forms of stress, such as heat shock, transiently synthesize a group of proteins called heat shock proteins (hsps). Although many stressors other than heat shock are known to induce hsps, inhibitors of hsp expression have never been reported. Here we show that quercetiri and several other flavonoids inhibit the synthesis of hsps induced by heat shock in two human cell lines, Hela cells and COLO320 DMcells. Quercetin inhibited the induction of hsp70 at the level of mRNAaccumulation. This is the first report to describe the inhibition of hsp expression by reagents.Whencells or organisms are exposed to heat shock,

BACKGROUNDAmplification of DNA in certain chromosomal regions plays a crucial role in the development and progression of human malignancies, specifically when protooncogenic target genes within those amplicons are overexpressed. Comparative genomic hybridization studies have revealed frequent amplification at 20q in primary breast tumors. The aim of the current study was to identify specific genes in the 20q amplicon that were likely to have clinical significance.METHODSThe authors examined 38 primary breast tumors by using a quantitative real‐time reverse transcription–polymerase chain reaction assay to determine expression levels of 18 potential targets for amplification events involving 20q. Potential correlations between elevated expression of the genes in question and clinicopathologic parameters or clinical outcomes were analyzed.RESULTSElevated expression of NABC1 was significantly associated with positive estrogen (P < 0.001) and progesterone (P = 0.027) receptors in breast tumors, and high expression of PTK6 was significantly correlated with positive estrogen receptor status (P = 0.022) and postmenopausal status (P = 0.008). Patients whose tumors showed elevated expression of NCOA3 (AIB1) had significantly shorter disease‐free (P = 0.017) and overall (P = 0.0021) survival times after surgery than did other patients with breast tumors. Reduced disease‐free survival, but not reduced overall survival, was associated with high expression of TOP1 (P = 0.035) and TFAP2C (P = 0.035).CONCLUSIONSTOP1, TFAP2C, and (particularly) NCOA3 may be prognostic indicators for patients with breast tumors. Cancer 2003;98:18–23. © 2003 American Cancer Society.DOI 10.1002/cncr.11482

Little is known about mechanisms of regulation of cysteine dioxygenase (CDO), γ-glutamylcysteine synthetase (GCS), and cysteine-sulfinate decarboxylase (CSDC) in response to diet. Enzyme activity and Western and Northern or dot blot analyses were conducted on liver samples from rats fed a basal low-protein diet or diets with graded levels of protein or methionine for 2 wk. Higher levels of CDO activity and CDO protein but not of CDO mRNA were observed in liver of rats fed methionine or protein-supplemented diets, indicating that CDO activity is regulated by changes in enzyme concentration. Lower concentrations of the heavy or catalytic subunit of GCS (GCS-HS) mRNA and protein, as well as a lower activity state of GCS-HS in rats fed methionine- or protein-supplemented diets, indicated that dietary regulation of GCS occurs by both pretranslational and posttranslational mechanisms. Lower CSDC activity, CSDC protein concentration, and CSDC mRNA concentration were found in rats fed the highest level of protein, and regulation appeared to involve changes in mRNA concentration. Regulation of key enzymes of cysteine metabolism in response to diet determines the use of cysteine for synthesis of its essential metabolites.

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