Beta-carotene is accumulated, metabolized, and possibly converted to retinol in human breast carcinoma cells (MCF-7).
The aims of the present study were to investigate the uptake, accumulation, and metabolism of beta-carotene by the human breast carcinoma cell line MCF-7. Beta-carotene uptake was time- and dose-dependent, and independent of cell polarity. Beta-carotene accumulation in cells was linear as a function of its concentration in medium (1.3-4.1 micromol/L). It was accompanied by increasing amounts of retinol, which accumulated in cells following a sigmoid pattern, and by other four putative metabolites. Beta-apocarotenals, epoxides, endoperoxides, retinal, retinoic acid, and retinyl esters were not detected in cell extracts. Beta-carotene and its metabolites did not induce alterations in cell morphology or subcellular localization of epithelial mucins. Beta-carotene and retinol were released from cells that had previously accumulated beta-carotene, and were further incubated in beta-carotene- and retinol-free medium, but intracellular retinol content remained constant whereas beta-carotene decreased. In conclusion, beta-carotene added to culture medium in physiological concentrations (1-6 micromol/L) is taken up and metabolized in MCF-7 cells, and is possibly converted to retinol.
Laboratorio de Bioquimica Nutricional e de Alimentos, Instituto de Química, Universidade Federal do Rio de Janeiro, 21949-900 Rio de Janeiro, Brazil.
Alexandre G
AG
Torres
Radovan
R
Borojevic
Nadia M F
NM
Trugo
D001940:Breast / Q000378:metabolism*; D001943:Breast Neoplasms; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D004847:Epithelial Cells / Q000378:metabolism; D006801:Humans; D014407:Tumor Cells, Cultured; D014801:Vitamin A / Q000378:metabolism*; D019207:beta Carotene / Q000008:administration & dosage / Q000378:metabolism*
D003470:Culture Media; D019207:beta Carotene; D014801:Vitamin A