Journal Article

Effect of β-carotene on cell cycle progression of human fibroblasts

Lucia Anna Stivala, Monica Savio, Ornella Cazzalini, Roberto Pizzala, Laura Rehak, Livia Bianchi, Vanio Vannini and Ennio Prosperi

in Carcinogenesis

Volume 17, issue 11, pages 2395-2401
Published in print November 1996 | ISSN: 0143-3334
Published online November 1996 | e-ISSN: 1460-2180 | DOI:
Effect of β-carotene on cell cycle progression of human

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The uptake of β-carotene (BC) and its effect on the cell cycle progression of normal human fibroblasts in primary culture were investigated by using two different delivery methods: exposure to BC solubilized in the organic solvent tetrahydrofuran (THF) or to BC incorporated into dipalmitoylphosphatidylcholine (DPPC) liposomes. Cell cycle progression was evaluated by immunofluorescence detection and flow cytometric analysis of the proliferating cell nuclear antigen (PCNA). In contrast to THF, which induced a marked reduction in the number of cells in S phase and in the extent of PCNA immunolabeling, DPPC liposomes proved to be an effective delivery system that does not interfere with cell proliferation. Cellular uptake of 0.23 nmol/106 cells was found after 24 h incubation in BC-containing DPPC liposomes. This value increased to 1.2 nmol/106 cells after 72 h. After the first day of incubation, the number of cells in S phase was reduced by ∼50%, with a consequent accumulation of cells in G1 phase. This effect was maintained up to 3 days incubation, with no detectable effects on cell viability. This cell cycle delay was found to be reversible, returning the percentage of cells in S phase to the control value 24 h after removal of BC from the medium. In order to determine whether the activity of BC could be attributed to the molecule itself or to its conversion into retinoids, the production of BC metabolites was assessed. Analysis of cellular levels of retinoids failed to demonstrate the presence of retinal, retinol, retinoic acid or retinyl esters during an incubation period of 6 days. These results suggest that in normal human fibroblasts, BC induces a cell cycle delay in the G1 phase and that this effect is independent of conversion to known retinoids.

Journal Article.  0 words. 

Subjects: Clinical Cytogenetics and Molecular Genetics

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