@article{6e825f1e94914725b0d2b4b1d7f82a6d,
title = "Potent and orally active purine-based fetal hemoglobin inducers for treating β-thalassemia and sickle cell disease",
abstract = "Reactivation of fetal hemoglobin (HbF) expression by therapeutic agents has been suggested as an alternative treatment to modulate anemia and the related symptoms of severe β-thalassemia and sickle cell disease (SCD). Hydroxyurea (HU) is the first US FDA-approved HbF inducer for treating SCD. However, approximately 25% of the patients with SCD do not respond to HU. A previous study identified TN1 (1) as a small-molecule HbF inducer. However, this study found that the poor potency and oral bioavailability of compound 1 limits the development of this inducer for clinical use. To develop drug-like compounds, further structure-activity relationship studies on the purine-based structure of 1 were conducted. Herein, we report our discovery of a more potent inducer, compound 13a, that can efficiently induce γ-globin gene expression at non-cytotoxic concentrations. The molecular mechanism of 13a, for the regulation HbF expression, was also investigated. In addition, we demonstrated that oral administration of 13a can ameliorate anemia and the related symptoms in SCD mice. The results of this study suggest that 13a can be further developed as a novel agent for treating hemoglobinopathies, such as β-thalassemia and SCD.",
keywords = "Fetal hemoglobin, Inducer, Sickle cell disease, β-Thalassemia",
author = "Lai, {Zheng Sheng} and Yeh, {Teng Kuang} and Chou, {Yu Chi} and Tsu Hsu and Lu, {Cheng Tai} and Kung, {Fang Chun} and Hsieh, {Ming Yen} and Lin, {Chun Hung} and Chen, {Chiung Tong} and Che-Kun Shen and Jiaang, {Weir Torn}",
note = "Funding Information: We evaluated the efficacy of ?-globin gene induction by 13a treatment using a primary human erythroid cell culture system. After 2 weeks of in vitro erythroid cell differentiation, cells were treated with 13a for 3 days and then harvested for reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis, cell viability assay, and western blot analysis. Fold change of ?-globin mRNA expression in primary human erythroid cell cultures was significantly increased by 13a treatment in a dose-dependent manner (working concentrations ranging from 0.06 ?M to 2 ?M, Fig. 2a). The maximal induction (4.8-fold) of the ?-globin gene by 13a was observed at the concentration of 2.0 ?M. Higher concentrations (4.0 ?M) of 13a treatment resulted in cell cytotoxicity, which reduced ?-globin induction. Importantly, primary human erythroid cells treated with 1.0 ?M 13a activated ?-globin mRNA expression by 3.8-fold without inducing significant cytotoxicity. In addition, the dose-dependent effects of HU and NaB were also evaluated (Supporting material, Fig. S1). HU (100 ?M) and NaB (250 ?M) provided maximal ?-globin inducing activities of 2.5- and 1.3-fold, respectively, in primary human erythroid cells. The CC50 values of HU and NaB (CC50 = 147 and 222 ?M, respectively) were determined for the next studies. We further evaluated the protein level of ?-globin. We found the ?-globin protein levels in 13a-treated cells were higher than those in the mock control (Fig. 2b and c). In contrast, we verified the specificity of 13a for inducing the ?-globin and ?-globin genes. We found that after 0.5 ?M 13a treatment, it can specifically induce ?-globin gene expression but not that of ?-globin (Fig. 2d). However, HU induced similar levels of ?-globin and ?-globin. Specificity is important for treating patients with SCD. The increase in the expression of the mutant ?-globin gene is not helpful for this disease. The RNA and protein results show that 13a can induce ?-globin gene expression without cytotoxicity and demonstrate the specificity to induce higher expression of the ?-globin gene than that of the ?-globin gene. These results indicate the dosing range and safety of 13a could be better than that of HU.Academia Sinica and The National Health Research Institutes financially supported the study. FACS core facility in Institute of Molecular Biology, Academia Sinica helped for flow cytometry analysis. Bioinformatics core in Institute of Molecular Biology, Academia Sinica helped for RNA-seq result analysis. Funding Information: Academia Sinica and The National Health Research Institutes financially supported the study. FACS core facility in Institute of Molecular Biology, Academia Sinica helped for flow cytometry analysis. Bioinformatics core in Institute of Molecular Biology, Academia Sinica helped for RNA-seq result analysis. Publisher Copyright: {\textcopyright} 2020 Elsevier Masson SAS",
year = "2021",
month = jan,
doi = "10.1016/j.ejmech.2020.112938",
language = "English",
volume = "209",
journal = "European Journal of Medicinal Chemistry",
issn = "0223-5234",
publisher = "Elsevier Masson SAS",
}