Bergamot (Citrus bergamia Risso) fruit extracts as γ-globin gene expression inducers: phytochemical and functional perspectives.
Department of Biology and Evolution, Agro-technological and Pharmaceutical Resources, Agri-Unife, University of Ferrara, Ferrara, Italy.
Epicarps of Citrus bergamia fruits from organic farming were extracted with the objective of obtaining derived products differently rich in coumarins and psoralens.
The extracts were chemically characterized by (1)H nuclear magnetic resonance (NMR), gas chromatography-flame ionization detection (GC-FID), gas chromatography-mass spectrometry (GC-MS), and high-pressure liquid chromatography (HPLC) for detecting and quantifying the main constituents.
Both bergamot extracts and chemical standards corresponding to the main constituents detected were then assayed for their capacity to increase erythroid differentiation of K562 cells and expression of γ-globin genes in human erythroid precursor cells.
Three experimental cell systems were employed:
(a) the human leukemic K562 cell line,
(b) K562 cell clones stably transfected with a pCCL construct carrying green-enhanced green fluorescence protein (EGFP) under the γ-globin gene promoter, and
(c) the two-phase liquid culture of human erythroid progenitors isolated from healthy donors.
The results suggest that citropten and bergapten are powerful inducers of differentiation and γ-globin gene expression in human erythroid cells.
These data could have practical relevance, because pharmacologically mediated regulation of human γ-globin gene expression, with the consequent induction of fetal hemoglobin, is considered to be a potential therapeutic approach in hematological disorders, including β-thalassemia and sickle cell anemia.
- J Photochem Photobiol B. 2008 Jul 24;92(1):24-8. Epub 2008 Apr 7.
Furocoumarins photolysis products induce differentiation of human erythroid cells.
Department of Pharmaceutical Sciences, University of Padova, Via Marzolo 5, University of Padova, 35131 Padova, Italy. email@example.com
Psoralens, also known as furocoumarins, are a well-known class of photosensitizers largely used in the therapy of various skin disease.
In this study we have evaluated the effects of crude pre-irradiated solutions of furocoumarins derivatives on
(a) erythroid differentiation and apoptosis of human leukemic K562 cells and (b) hemoglobin synthesis in cultures of human erythroid progenitors derived from the peripheral blood.
To prove the activity of a mixture of photoproducts generated by UVA irradiation of the three psoralen derivatives 5-methoxypsoralen (5-MOP) 8-methoxypsoralen (8-MOP), and angelicin (ANG), we employed the human leukemic K562 cell line and the two-phase liquid culture procedure for growing erythroid progenitors.
The results obtained demonstrate that pre-irradiated solutions of psoralen derivatives significantly induce erythroid differentiation of K562 cells irrespective of the type of derivative used, suggesting that the active photoproduct(s) share a common structure. Interestingly, solutions of psoralens irradiated in anaerobic conditions do not exhibits erythroid inducing ability, indicating that the effect is mostly due to photooxidized psoralen products.
In erythroid precursor cells, psoralens photolysis products stimulates at low concentrations an increase of hemoglobin A and hemoglobin F. Altogether, these data suggest that photoproducts of psoralen warrant further evaluation as potential therapeutic drugs in beta-thalassaemia and sickle cell anaemia.
- [PubMed - indexed for MEDLINE]
- Biochem Pharmacol. 2008 Feb 15;75(4):810-25. Epub 2007 Oct 13.
Induction of gamma-globin mRNA, erythroid differentiation and apoptosis in UVA-irradiated human erythroid cells in the presence of furocumarin derivatives.Viola G, Vedaldi D, Dall'Acqua F, Fortunato E, Basso G, Bianchi N, Zuccato C, Borgatti M, Lampronti I, Gambari R.
Department of Pharmaceutical Sciences, University of Padova, Via Marzolo 5, 35131 Padova, Italy. firstname.lastname@example.org
Psoralens, also known as furocoumarins, are a class of photosensitizers largely used in the therapy of various skin diseases.
In this study we have evaluated the combined effects of UVA irradiation and furocoumarins derivatives on (a) erythroid differentiation and apoptosis of human leukemia K562 cells and (b) globin gene expression in cultures of human erythroid progenitors derived from the peripheral blood.
To prove the activity of a series of linear and angular furocoumarins derivatives, we employed the human leukemia K562 cell line and the two-phase liquid culture procedure for growing erythroid progenitors. Quantitative real-time reverse transcription polymerase-chain assay (Q-RT-PCR) was employed for quantification of the accumulation of globin mRNAs.
The results obtained demonstrate that both linear and angular furocoumarins are strong inducers of erythroid differentiation of K562 cells. From a preliminary screening, we have selected two derivatives, 5-methoxypsoralen (5-MOP) and trimethylangelicin (TMA), for which we have investigated their mechanism of action.
The cell cycle analysis showed that these derivatives induce, after irradiation, a cell cycle arrest in the G2/M phase, followed by apoptosis. Mitochondrial depolarisation and caspases activation seem to be involved in the mechanism of cell death.
In erythroid precursor cells, psoralens in combination with UVA irradiation, stimulate at very low concentrations a preferential increase of gamma-globin mRNA.
Altogether, these data suggest that psoralen derivatives warrant further evaluation as potential therapeutic drugs in beta-thalassemia and sickle cell anemia.
- [PubMed - indexed for MEDLINE]