β-Carotene Uptake and Bioconversion to Retinol Differ Between Human Melanocytes and Keratinocytes

Division of Dermatology, Department of Biomedicine and Surgery, Clinical Research Center, Faculty of Health Sciences, Linköping University, Linköping, Sweden.
Nutrition and Cancer (Impact Factor: 2.32). 02/2001; 39(2):300-6. DOI: 10.1207/S15327914nc392_21
Source: PubMed


beta-Carotene is one of the carotenoids that has been considered to play a role in the natural defense against ultraviolet-induced skin cancer. It is not known whether epidermal cells are able to accumulate beta-carotene and, subsequently, convert it to vitamin A. We used normal cultured human keratinocytes and melanocytes to study the uptake, and possible bioconversion to retinol, of authentic or [14C]beta-carotene. The uptake was much higher in melanocytes than in keratinocytes, corresponding to a fivefold difference in the intracellular fraction after two days of incubation. An increased level of cellular retinol was noted after one day of beta-carotene incubation. The conversion of [14C]beta-carotene to [14C]retinol peaked at 24 hours of incubation in keratinocytes and melanocytes. The results suggest that beta-carotene can function as a local supply of vitamin A in the skin and that melanocytes are especially likely to store beta-carotene.

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    • "( 94030304 ; Sigma - Aldrich , St . Louis , MO , USA ) were cultured in Eagle ' s minimum essential medium ( EMEM ) GlutaMAX , supplemented with 50 IU / ml penicillin - G , 50 µg / ml streptomycin , and 10% fetal bovine serum ( all from Gibco , Paisley , UK ) . Melanocytes were kindly provided by Petra Wäster and cultured as described previously ( Andersson et al . , 2001 ) . Human cervical cancer cells HeLa ( CCL - 2 ; ATCC ) , breast cancer cells MDA - MB - 231 ( HTB - 26 ; ATCC ) and human colon cancer HCT - 116 ( CCL - 247 ; ATCC ) were cultured in Dulbecco ' s modified eagle medium GlutaMAX supplemented with 50 IU / ml penicillin - G , 50 µg / ml streptomycin and 10% fetal bovine serum . Cells were "
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    Frontiers in Chemistry 10/2015; 3. DOI:10.3389/fchem.2015.00058
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    • "All experiments were performed according to the ethical principles of the Helsinki declaration and approved by the Ethical Committee at Linkö ping University, Linkö ping, Sweden. Melanocytes were obtained from Caucasian donors (0–3 years of age) by means of foreskin circumcisions and pure cultures were established as described previously (Andersson et al., 2001). The melanocytes were cultured in Medium 199 with 2% fetal bovine serum and supplemented with 50 U/ml penicillin, 50 mg/ml streptomycin, 50 mg/ ml fungizone, 10 ng/ml basic fibroblast growth factor, 10 mg/ml inositol (all from Invitrogen, Paisley, Scotland, UK), 10 mg/ml insulin, 0.1 nM cholera toxin, 0.4 mg/ml hydrocortisone, 1 nM triiodothyronine , 10 mg/ml transferrin (all from Sigma Aldrich, St Louis, MO), and 10 ng/ml epidermal growth factor (Roche Diagnostics, Mannheim, Germany) (Gilchrest et al., 1984). "
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    ABSTRACT: L'épiderme humain contient des rétinoides endogènes et des caroténoïdes. Nous présentons une méthode d'évaluation de la pénétration et du métabolisme des rétinoïdes (acide rétinoïque, rétinaldéhyde, rétinol, palmitate-de-rétinyle) dans la peau humaine "ex-vivo" à partir de peau totale incubée dans des cellules de Franz. Les résultats montrent qu'il n'y a pas de métabolisme pour l'acide rétinoïque, forme active de la vitamine A qui lie les récepteurs nucléaires, alors qu'on observe un métabolisme d'oxydation et de réduction pour le rétinaldehyde, ainsi qu'une augmentation des rétinoïdes endogènes pour le rétinol et ses esters. Nous mettons en évidence pour la première fois que le β-carotène est un précurseur de la vitamine A dans l'épiderme humain. Nous montrons un effet filtre de la vitamine A (palmitate-de-rétinyle) "in vivo" chez l'homme qui contribue potentiellement à la protection de l'ADN contre les effets des UVB.
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