The Journal of nutrition
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The Journal of nutrition · Feb 2003
Beta-carotene regulates NF-kappaB DNA-binding activity by a redox mechanism in human leukemia and colon adenocarcinoma cells.
We demonstrated previously that beta-carotene may affect cell growth by a redox mechanism. The purpose of this study was to determine whether the redox-sensitive transcription factor nuclear factor (NF)-kappaB may be involved in the growth-inhibitory and proapoptotic effects of the carotenoid. To test this hypothesis, human leukemic cells (HL-60) and colon adenocarcinoma cells (LS-174 and WiDr) were treated with beta-carotene, alone or in combination with alpha-tocopherol or N-acetylcysteine, and changes in 1) cell oxidative status, 2) cell growth and apoptosis, 3) DNA-binding activity of NF-kappaB and 4) expression of c-myc, a NF-kappaB target gene involved in apoptosis, were evaluated. ⋯ Colon adenocarcinoma cells displayed substantial differences in their sensitivity to beta-carotene, exhibiting increased ROS levels and activation of NF-kappaB at concentrations much lower in LS-174 cells (2.5-5.0 micro mol/L) than in WiDr cells (50-100 micro mol/L). In all cell lines studied, alpha-tocopherol and N-acetylcysteine inhibited the effects of beta-carotene on NF-kappaB, cell growth and apoptosis, and normalized the increased expression of c-myc induced by the carotenoid. These data suggest that the redox regulation of NF-kappaB induced by beta-carotene is involved in the growth-inhibitory and proapoptotic effects of the carotenoid in tumor cells.
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The National Nutrition Monitoring and Related Research Program (NNMRRP) arose from Congressional concern about lack of information regarding the occurrence in the American population of undernutrition and diet-related risk factors for chronic diseases. Congressional appropriations and executive branch decisions about budget priorities have been the major determinants of the scope and number of nutrition monitoring surveys and surveillance activities fielded and therefore the information available for policy and research uses. ⋯ The NNMRRP-derived dietary and nutritional status data are essential information for quantitative risk assessments increasingly relied on by regulatory agencies as the basis for programmatic decisions and regulations development. Users of NNMRRP data in government agencies, academic institutions and the private sector have come to recognize the value of data from the surveys and surveillance systems for a wide variety of programmatic and research purposes.