Browsing by Author "Matos, Elisabete Cristina Conceição de"
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- Natural compounds with the capacity to reactivate the gene of gamma-globin and induction of fetal hemoglobin - In vitro testPublication . Matos, Elisabete Cristina Conceição de; Brito, Miguel; Ribeiro, Edna Soraia Gregórioβ-hemoglobinopathies are the most common recessive genetic diseases worldwide. Currently available treatments for these disorders are expensive and associated with severe side effects. Pharmacological reactivation of Fetal Hemoglobin (HbF) is seen as a promising therapeutic strategy. Hydroxyurea (HU), a potent ribonucleotide reductase inhibitor, is the only Food and Drug Administration (FDA) approved HbF inducing agent. However, its cytotoxicity, potential carcinogenicity and variable clinical effects limit severely its use. Identification of novel agents, with higher HbF inducing activity, lower cytotoxicity and available in low-income countries, such as natural compounds, has become a great challenge today. Here, we performed an assessment of potential transcriptional effects induced by two natural bioactive compounds, namely Genistein (GN) a naturally occurring flavonoid found in soybean and soy derivates and Epigallocatechin-3-gallate (EGCG) the major polyphenol component of green tea, in globin and HbF regulators/silencer genes. K562 cell line was exposed for 72 and 96 hours to three different concentrations of GN and EGCG that mimic cellular exposure in vivo after supplementation (100 ƞg/ml, 250 ƞg/ml and 500 ƞg/ml), and 25 μg/ml HU was used as a positive control. Cell viability and proliferation were measured and the transcriptional effects of GN and EGCG on α, β and γ-globin genes, as well as the HbF regulators genes BCL11A and KLF1, were evaluated by qRT-PCR using specific primers. Our results demonstrated that both compounds impact cellular metabolism and proliferation with no cytotoxic effects and have a potential specific molecular target for BCL11A with associated downregulation, without altering KLF1 levels. GN and EGCG also affected globin expression levels in a dose and time-dependent manner. Interestingly, transcriptional analysis of both compounds revealed non-monotonic dose-responses (NMDRs). Overall, our preliminary study sustains the potential of these compounds for γ-globin reactivation and consequently HbF induction, which indicates that GN and EGCG may be potential candidates for new therapeutic strategies. Further research must be performed in order to assess the effectiveness of HbF induction and the underlying molecular mechanisms.
- Natural compounds with the capacity to reactivate the gene of gamma-globin and induction of fetal hemoglobin: in vitro testPublication . Matos, Elisabete Cristina Conceição de; Brito, Miguel; Ribeiro, EdnaABSTRACT - β-hemoglobinopathies are the most common recessive genetic diseases worldwide. Currently available treatments for these disorders are expensive and associated with severe side effects. Pharmacological reactivation of Fetal Hemoglobin (HbF) is seen as a promising therapeutic strategy. Hydroxyurea (HU), a potent ribonucleotide reductase inhibitor, is the only Food and Drug Administration (FDA) approved HbF inducing agent. However, its cytotoxicity, potential carcinogenicity, and variable clinical effects limit severely its use. Identification of novel agents, with higher HbF inducing activity, lower cytotoxicity, and availability in low-income countries, such as natural compounds, has become a great challenge today. Here, we performed an assessment of potential transcriptional effects induced by two natural bioactive compounds, namely Genistein (GN) a naturally occurring flavonoid found in soybean and soy derivates, and Epigallocatechin-3-gallate (EGCG) the major polyphenol component of green tea, in globin and HbF regulators/silencer genes. K562 cell line was exposed for 72 and 96 hours to three different concentrations of GN and EGCG that mimic cellular exposure in vivo after supplementation (100 ƞg/ml, 250 ƞg/ml and 500 ƞg/ml), and 25 μg/ml HU was used as a positive control. Cell viability and proliferation were measured and the transcriptional effects of GN and EGCG on α, β, and γ-globin genes, as well as the HbF regulators genes BCL11A and KLF1, were evaluated by qRT-PCR using specific primers. Our results demonstrated that both compounds impact cellular metabolism and proliferation with no cytotoxic effects and have a potential specific molecular target for BCL11A with associated downregulation, without altering KLF1 levels. GN and EGCG also affected globin expression levels in a dose and time-dependent manner. Interestingly, transcriptional analysis of both compounds revealed non-monotonic dose-responses (NMDRs). Overall, our preliminary study sustains the potential of these compounds for γ-globin reactivation and consequently HbF induction, which indicates that GN and EGCG may be potential candidates for new therapeutic strategies. Further research must be performed in order to assess the effectiveness of HbF induction and the underlying molecular mechanisms.