β-Carotene Inhibits Growth of Human Colon Carcinoma Cells in Vitro by Induction of Apoptosis
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Abstract
Epidemiological studies suggest that βcarotene is able to modulate the risk of cancer. A number of in vitro studies reported that βcarotene inhibits the growth of cancer cells; however, so far little is known about the molecular mechanisms of the antiproliferative effect of βcarotene. Here we have investigated the effects of two βcarotene preparations, (i) βcarotene dissolved in tetrahydrofuran (final concentration in cell culture medium: 0.5%) and (ii) βcarotene incorporated in a water dispersible bead form, on cultured human colon carcinoma cells HT29. The treatment of cells with βcarotene up to 30 M for 72 h led to a significant increase in the cellular βcarotene concentration and formation of retinol. βCarotene showed only low cytotoxicity for confluent cells tested up to 30 M, but at dietary relevant concentrations for the intestinal tract (10, 30 M) βcarotene was strongly cytotoxic for growing cells and induced apoptosis in HT29 cells as assessed by the AnnexinV assay (the maximal effect was observed 15 h after treatment with βcarotene). Exposure of cells to retinol at concentrations yielding cellular retinol levels similar to those observed by βcarotene treatment had no antiproliferative or cytotoxic effect. Furthermore, βcarotene did not affect the activation of the extracellular signalregulated kinases (ERK1 and ERK2) that are essential for cellular growth. In summary, βcarotene can inhibit growth of human colon carcinoma cells in vitro by induction of apoptosis in proliferating cells.
Copyright © 2001 by Walter de Gruyter GmbH & Co. KG
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- Erratum
- Acknowledgement
- Content Index
- Author Index
- Subject Index
Articles in the same Issue
- New Control of Mitochondrial Membrane Potential and ROS Formation A Hypothesis
- Brix from Xenopus laevis and Brx1p From Yeast Define a New Family of Proteins Involved in the Biogenesis of Large Ribosomal Subunits
- Mig-6 Is a Negative Regulator of the Epidermal Growth Factor Receptor Signal
- β-Carotene Inhibits Growth of Human Colon Carcinoma Cells in Vitro by Induction of Apoptosis
- Ligand-Mediated Protection against Phage Lysis as a Positive Selection Strategy for the Enrichment of Epitopes Displayed on the Surface of E. coli Cells
- Structural and Redox Properties of the Leaderless DsbE (CcmG) Protein: Both Active-Site Cysteines of the Reduced Form Are Involved in Its Function in the Escherichia coli Periplasm
- Polyphenols of Cocoa: Inhibition of Mammalian 15-Lipoxygenase
- Total Antioxidant Capacity and Nuclear DNA Damage in Keratinocytes after Exposure to H2 O2
- Recombinant Cryptic Human Fibronectinase Cleaves Actin and Myosin: Substrate Specificity and Possible Role in Muscular Dystrophy
- Rat Tripeptidyl Peptidase I: Molecular Cloning, Functional Expression, Tissue Localization and Enzymatic Characterization
- Determination of NADH in Frozen Rat Brain Sections by Laser-Induced Fluorescence
- Human -Calpain: Simple Isolation from Erythrocytes and Characterization of Autolysis Fragments
- Erratum
- Acknowledgement
- Content Index
- Author Index
- Subject Index
